LED点阵显示屏中英文对照外文翻译文献

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LED显示屏中英文手册

LED显示屏中英文手册

LED电子显示屏用户手册LED electron display handbook for consumerLED电子显示屏硬件部分LED electron display hardware partLED电子显示屏保修证书LED electron display warranty certificate警告Warning警告:为了防止任何身体上的伤害,请在连接开关之前,读这个安装操作规则Warning:To protect any body damage ,please install the instruction before you connect the switch.1在打开开关前,检查所有的交流电源是不是连接好。

Before you open the switch .please check if all the alternating current power were connected correct.2在做任何维护工作之前要先关掉包括LED板`电脑终端`系统盒和监控器在内的所有开关.Please close the switch of LED board ,the computer terminal system box and monitor ,before you do any maintenance.3在开关未关闭时,不要触电源。

When you open the switch ,don't touch the power .警告:为了安装设备驱动程序的损失和数据的丢失,请在操作显示板之前读这个安装设置操作规则。

Warning: To avoid the damage of the driver and the data disappear ,please read the operation rule of the installation device before you operate with the led.1在连接任何电缆之前,请先关掉包括LED板`电脑终端`系统盒和监控器在内的所有开关。

关于LED的外文文献和中文译文

关于LED的外文文献和中文译文

多个LED发光装置的新型采集系统作为光源的一种,发光二极管(LED)有很多优点。

LED集成度更高,颜色种类多,使用寿命更长,而且工作电压较低。

但是,它仍有一个非常大的缺陷:一只LED的光照强度还是比较低。

这个缺点导致显示屏上的光通量不会很高。

但是无论如何,LED还是以其出色的性能在低电压装置中普遍应用。

因此,利用此系统采集多个LED的光,集成为更高强度的照明装置。

本设计提出三种采集系统,来实现增强光强的功能。

效率最好的一种采集系统可以达到96%。

同时,还分析了本系统的制造误差以及预算。

1 简介利用传统的光源来设计一个便携式探照灯,尺寸和能耗会很大。

而利用LED 来设计将会避免这些问题。

LED有很多优点:节能、体积较小、使用寿命长(约100,103小时)等,尤其是LED的光很适合环境工作。

Carel Zeiss和Philips打算用LED光源设计两种便携式探照灯。

尽管LED有诸多优点,可以让他们设计出的探照灯更加便携和小巧,但是由于光学元件的转换效率问题,导致系统有很多困难。

解决这个困难将是本文研究的重点。

通常,用一种合成非线性集中器(CPC)来减小分散度。

但是,这种传统的CPC采集效率仅为72%,必须要改善采集效率来提高光的利用率。

本文中将解决分散度和采集效率两个问题。

为实现这个目标,设计了三种不同的采集系统,以提高效率,下面逐一介绍。

2 仿真部分利用光学仿真软件和标签查找模块(BRO),来设计并分析采集系统的性能。

LED光源部分来自Osram-Opical半导体。

远程LED光源是一种Lambertian模式,LED的规格见表1。

在采集系统的底部有四个LED。

系统各个LED之间的位置关系如图1。

通光部分为2.1×2.1mm2,孔径3.26mm。

LED阵列对称的分布于系统的底部。

采集系统的第一个光学元件为均质器。

这个均质器的受光角度是12.5°。

因此,这个系统就是要把LED的受光角度的范围控制在±60°到±12.5°之间。

LED点阵的外文翻译---纳米结构InGaN发光Diodesfor固态照明

LED点阵的外文翻译---纳米结构InGaN发光Diodesfor固态照明

(要求翻译与毕业设计(论文)相关的外文文献两篇,且3000单词以上/ 篇,将译文附在原文之后)第一篇:[ 所译外文资料:①作者:Taeil Jung②书名(或论文题目):Nano-structured InGaN Light-Emitting Diodesfor Solid-State Lighting③出版社(或刊物名称或可获得地址):All Rights Reserved.④出版时间(或卷期号):2009.⑤所译起止页码:Nano-structured InGaN Light-Emitting Diodesfor Solid-State LightingSolid-state lighting can potentially reduce the electricity consumption by 25%. It requires high efficiency light-emitting diodes across the visible spectrum. GaN and related materials have direct band gap across the entire visible spectrum and are ideal for future solid-state lighting applications. However, materials defects, polarization charges, and total internal reflection have thus far limited the efficiencies of InGaN LEDs, in particular InGaN LEDs in the green/yellow wavelength range, which are critical in achieving highly efficient LED luminaries with an excellent color-rendering indexIn this Thesis, we have developed and demonstrated that novel in situ nanostructured GaN processes in MOCVD are effective in improving the efficiencies of InGaN LEDs. InGaN LEDs grown on quasi-planar semi-polar GaN templates were proven to exhibit three times higher internal quantum efficiencies and negligible quantum confined Stark effect using selective area epitaxy. InGaN LEDs grown on nanostructured semi-polar GaN templates are also effective to improve the internal quantum efficiency by 31%. The same in situ processes are also effective in reducing the defect density by an order of magnitude and increasing the photon extraction efficiency as a factor of two.The in situ processes include in situ silane treatment and high temperature overgrowth. Both processes require only standard MOCVD tools and hence are cost effective and suitable for mass-production. In situ silane treatment treatsc-plane GaN samples with silane under ammonia environment, generating nano-scale truncated cone structures with up to 200 nm scale. These truncated cone structures can be subsequently transformed into pyramidal nanostructures comprising of only (10-11) and (11-22) semipolar planes using high temperature overgrowth. These processes were applied to both InGaN active region and the LED surface to improve the internal quantum efficiency and the photon extraction efficiency, respectively. Extensive materials, device, and optical characterizations have been carried out in this research.1.1 Gallium Nitride Materials for Optoelectronic ApplicationsGallium nitride based materials, including GaN, AlN, InN, and their alloys, are excellent candidates for short-wavelength optoelectronic applications. Their direct bandgaps extend from ultraviolet to near-infrared. In addition, they exhibit high mechanical and thermal stabilities compared to other III-Vsemi-conductors, making them especially suitable for high-power andhigh-temperature operations. In recent years, breakthroughs in p-type doping and defect reduction have led to the commercialization of GaN based laser diodes, light-emitting diodes (LEDs), high electron mobility transistors (HEMT) and hydrogen detectors. Despite these advances, many technological challenges such as green gap and substrate growths still remain.Perhaps one of the most important applications for GaN based materials is solidstate lighting (SSL). Worldwide, lighting constitutes 20% of electricity consumption while its efficiency is much lower than 25%. In contrast, efficiency of space heating has exceeded 90%. To this end, the development of highly efficient and reliable LEDs for solid-state lighting has been very active in both industry and academia in the past few years. It is projected by the US Department of Energy that by 2015, if successful, solidstate lighting can reduce the overall electricity consumption by 25%.Unlike GaAs and InP based semi-conductors, GaN based materials have suffered from a high density of defects due to very limited availability of lattice-matched GaN substrates. Up to now, most GaN based optoelectronic devices have been fabricated using hetero-epitaxy on foreign substrates such as sapphire (Al2O3), silicon carbide (SiC), and aluminum nitride (AlN), and in a very small percentage on silicon. Because of large lattice mismatch, GaN grown on these substrates often exhibits a high density of threading dislocations, typically on the order of 108 – 1010 /cm2. These defects are still one of the major limiting factors for the performance of GaN based optoelectronic devices, acting as non-radiative recombination and scattering centers. Achievement of lower defect density would also improve device reliability, resulting in a longer lifetime. Various defect reduction approaches, such as epitaxial lateral over-growth (ELOG), have been demonstrated and some of the details will be discussed in Chap.1.3.1. As part of this thesis, we have explored a novel approach to using nano-structured GaN to effectively lower the threading dislocation density.Among various epitaxial techniques that have been developed for GaN based materials, metal-organic chemical vapor deposition (MOCVD) is the leading technology. The typical growth temperature for GaN materials is around 1000 to 1200°C. This high growth temperature is necessary to improve the crystal quality and is a result of low cracking efficiency of the nitrogen source, ammonia (NH3), at a low temperature. In Chapter 2, I will summarize my contributions to successfully ramp up an MOCVD tool for the epitaxial growth of GaN LEDs for this research.1.2 InGaN LEDs for Solid-State LightingThe basic component for SSL is a white-light LED. As shown in Figure 1-1, itcan be achieved by mixing various color components, which can be generated either from the direct output of individual LEDs or from color-conversion materials, such as phosphor. To date, commercially available white-light LEDs usually consist of a blue emitter and a yellow phosphor plate. It has been shown that InGaN based blue LEDs could achieve external quantum efficiency in excess of 70% [1, 2]. However, this di-chromatic configuration typically has a poor color rendering index due to the lack of green and red components. The phosphor conversion process also limits the overall luminous efficiency due to energy loss during downconversion. To achieve luminous efficiency in excess of 200 lm/W and a color rendering index (CRI) in excess of 90, which is required for general illumination, a further improvement in blue LED efficiency and the use of tetra-chromatic configuration (blue + green + yellow + red) is necessary [3].* Unfortunately, the efficiency of both InGaN and AlInGaP LEDs decreases significantly in the green-yellow (500 - 580 nm) range. This efficiency gap is also known as “green gap”. Because AlInGaP materials have indirect bandgaps in this wavelength range, to achieve high-efficiency SSL, it is crucial to significantly improve the luminousNote that a trichromatic (e.g. blue + green + red) source cannot achieve a CRI > 90. efficiency of green and yellow InGaN LEDs. In this thesis, we will address these challenges using nano-structured GaN.Figure 1-1. Illustration of various potential white-light LEDs configurations (after Ref. [4]).1.3Limiting Factors for InGaN LEDs EfficiencyTo date, the efficiencies of InGaN LEDs are still limited by materials defects, polarization charges, and photon trapping. In this Section, we will briefly review the state of theart and overview how this research helps address these limitations.1.3.1 Materials DefectsAs mentioned before, the high defect density in GaN based materials grown on foreignsubstrates increases the non-radiative recombination rate and lowers the radiative efficiency. To date, several techniques have been demonstrated to improve the crystal quality and reduce the threading dislocation (TD) density of the GaN layer. Substrate pretreatmentat the growth temperature in an ammonia environment, also known as nitridation [5-7], has been shown to be critical for high quality GaN epilayers. The TD density of a typical GaN layer grown on c-plane sapphire substrate can be reduced to 108/cm2 [8] by employing the combination of a low temperature (LT; 450 - 600 °C)nucleation layer (NL) and a short annealing at the growth temperature to change the phase of the as-grown NL from cubic to hexagonal [9-11]. As will be discussed in Chapter 2, careful optimization of these low temperature growth sequences can significantly alter the subsequent GaN template growth. To this end, a home-made optical in situ monitoring tool (reflectometry) was established and will be discussed extensively in Chapter 2.In addition low temperature buffer growth, epitaxial lateral overgrowth (ELOG) which is a variation of selective area epitaxy (SAE) has been introduced [12, 13] to further lower the TD density by an order of magnitude to below 107/cm2. Variations of ELOG including pendeo- (from the Latin : hang on or suspended from) epitaxy (PE) [14] and multi-step ELOG are also effective to further reduce the TD density. Additional techniques such as TiN nano-porous network [15] and anodic aluminum oxide nano-mask [16] have also been proposed and demonstrated. All these methods, however, require ex situ processing and hence will add complexity and cost to the manufacturing. In this thesis, we will explore and generalize an in situ silane treatment approach to effectively lowering the TD density by an order of magnitude.1.3.2 Polarization ChargesDue to the non-cubic symmetry of GaN materials, compressively-strained active regions in InGaN LEDs exhibit both spontaneous and piezoelectric polarization charges. These polarization charges induce a strong internal electric field (IEF), typically on the order of MV/cm, in the active region, resulting in both efficiency droop at a high injection current density and the decrease of radiative efficiency with an increasing emission wavelength. The IEF can separate electrons from holes and increase electron leakage, resulting in low internal quantum efficiency (IQE) and efficiency droop [17], respectively. The suppression of the IEF, which is expected to increase IQE and the current density at which efficiency droop occurs, can be achieved by reducing the lattice mismatch in hetero-structures or growing them on semi-polar (e.g. {10-11} and {11-22}) and non-polar (e.g. a-plane and m-plane) surfaces. Because indium incorporation is more difficult on non-polar planes than on semi-polar planes, it is more advantageous to fabricate long-wavelength green-yellow LEDs on semi-polar planes to suppress the IEF.At least three approaches to fabricating semi-polar InGaN LEDs have been reported thus far. These include the growth of a GaN epilayer on spinel substrates [18], on bulk GaN substrates [19-27], and on the sidewalls of pyramidal or ridge GaN structures created on planar polar GaN surfaces using SAE [28-35]. GaN grown on spinel substrates have so far exhibited a high density of threading dislocations and stacking faults, thereby compromising the potential improvement of efficiency from the lowering of IEF. The use of bulk semi-polar GaN substrates has demonstrated the advantage of a lower IEF for the enhanced efficiency of green and yellow LEDs [25, 26]. However, limitations such as prohibitively high wafer cost and small substrate size need to be resolved before this approach can become more practical. On the other hand, the SAE technique can create semi-polar planes on polar GaN surfaces.High quality polar GaN films have been fabricated from a variety of substrates including sapphire, 6H-SiC, and bulk GaN by MOCVD. Using growth rate anisotropy and three-dimensional growth, different semi-polar and non-polar GaN planes can be generated on c-plane GaN [13]. In Chapter 3, we will show that high quality InGaN multiple quantum wells (MQWs) which exhibit IQE as large as a factor of three compared to polar MQWs can be grown on pyramidal GaN microstructures. This approach, however, requires ex situ patterning processes and does not easily produce a planar structure for electrical contacts. In this thesis, a new semi-polar LED structure is investigated, which is enabled by a novel epitaxial nanostructure, namely the nanostructured semi-polar (NSSP) GaN, which can be fabricated directly on c-plane GaN but without the issues of the SAE technique mentioned above [36]. NSSP GaN also eliminates the issues of excessive defects for GaN grown on spinel substrates and lowers the cost of using bulk semi-polar GaN substrates. As we will show later, the surface of NSSP GaN consists of two different semi-polar planes: (10-11) and (11-22). Therefore it is expected that InGaN active regions fabricated on NSSP GaN can exhibit a low IEF, and hence much improved IQE.1.3.3 Photon ExtractionAfter photons are generated from the active region in LEDs, they need to escape the device in order to be useful. When light travels from a medium with a higher refractive index to a medium with a lower refractive index, total internal reflection (TIR) occurs at the interface. In InGaN LEDs, photons experiencing TIR at LED surfaces can be re-absorbed by the active region or trapped in the device due to a wave-guiding effect as shown in Figure 1-2. In a simple InGaN LED, only 4% of photons generated from the active region can escape from each device surface. It has been shown that surface textures on LED surfaces can greatly reduce TIR and improve photon extraction efficiency as illustrated in Figure 1-2. To date, many surface texturing techniques such as photonic crystal structures [37] and photo-electrochemical etching of GaN surfaces [38] have been introduced. Notably, the photo-electrochemical etching of nitrogen-terminated GaN surface has been successfully implemented into commercial blue LEDs [2]. However, these approaches all require additional ex situ patterning processes which add significant costs.In this thesis, we investigate an in situ process to fabricate nano-structured GaN surfaces on LEDs which effectively improves the photon extraction efficiency. Figure 1-2. Light traveling within waveguides (left) with a smooth interface and (right) with a rough interface (after [39]).1.4 Organization of the ThesisThe objective of this thesis is to investigate cost-effective nanofabrication techniques that can significantly improve the efficiency of the state-of-the-art InGaN LEDs in both blue and green/yellow ranges for high performance solid-state lighting. The organization of this thesis is as follows.In Chapter 2, a summary of the MOCVD techniques for InGaN LEDs is given. In Chapter 3, we study the dependence of InGaN LED IQE on {10-11} semi-polar planes using SAE. In Chapter 4, fabrication and characterization of novel andcost-effective nano-structured GaN templates will be described. Using in situ silane treatment (ISST) and high temperature overgrowth (HTO), the formation of nano-scale inverted cone structures and nano-structured semi-polar (NSSP) templates has been obtained. In Chapter 5, we study InGaN semi-polar LEDs based on NSSP templates. An improvement of internal quantum efficiency is demonstrated.A green semi-polar InGaN LED grown on a c-plane substrate is also demonstrated. In Chapter 6, current spreading in NSSP InGaN LEDs will be discussed. In Chapter 7, the application of ISST for theimprovement of photon extraction efficiency of an InGaN LED will be discussed. In Chapter 8, we will summarize and make suggestions for future work.2.1 Gallium Nitride GrowthAs mentioned in the Introduction, gallium nitride (GaN) and related alloys are excellent candidates for future solid-state lighting. To date, III-nitride epitaxial growth has been limited by the lack of sufficiently large single crystal substrate for homoepitaxial growth. Therefore, the growth of GaN and related materials has been largely based on hetero-epitaxy using hydride vapor phase epitaxy (HVPE), metal organic chemical vapor deposition (MOCVD), and molecular beam epitaxy (MBE). Among these techniques, MOCVD is the leading technology due to the advantages on material quality, scalability, and cost [40]. The material quality of GaN grown by MOCVD has been excellent owing to its relatively high growth temperature (1000 - 1200°C) [41, 42].To date, various substrate materials including sapphire (Al2O3), silicon carbide (SiC), and silicon have been studied for GaN growth (Table 2-1). Although GaN substrates have been recently introduced in markets through bulk material growth on foreign substrates using HVPE and laser cutting along specific crystal planes, the cost has been prohibitively high. On the other hand, GaN grown on c-plane (0001) sapphire substrate exhibits stable growth over a wide range of growth conditions despite high dislocation density at the interface between thesubstrate and epitaxial layer. In this research, I have helped ramping up an MOCVD system together with Dr. Hongbo Yu. In this Chapter, I will summarize the MOCVD technologies and defect reduction strategies for InGaN light-emitting diodes (LEDs) epitaxy that will be used throughout this Thesis.2.1.1 GaN Growth Using MOCVDDue to a large lattice mismatch between GaN and sapphire, it is important to contain the defects near the GaN/sapphire interface such that the defect density can be minimized in the device region. Such optimization is achieved using in situ reflectometry [44, 45]. A home-made reflectometry system shown in Figure 2-1 was established in our 3 x 2” Thomas-Swan Close-Coupled Showerhead (CCS) MOCVD system. White light is reflected from the sample surface and monitored by a spectrometer during the growth. The reflectivity is sensitive to both the surface morphology and the epitaxial layer structure.Figure 2-1. Illustration of a home-made in situ reflectometry system integrated into the MOCVD system.Figure 2-2. Typical growth conditions for GaN templates used in this research.Typical growth conditions for GaN templates used in this research are summarized in Figure 2-2 and Table 2-2. Unless otherwise mentioned, c-plane sapphire substrates were used. The five steps outlined in Table 2-2, including high temperature (HT) cleaning, nitridation, low temperature (LT) nucleation, annealing of LT nucleation layer, and HT GaN growth, are crucial for high quality GaN epilayer.Figure 2-3 and Table 2-3 show the corresponding in situ reflectometry signal.In the following, we will describe how the reflectometry signal can be used to optimize the GaN template growth. Unless otherwise mentioned, we will refer to the reflectometry signal shown in Figure 2-3.Figure 2-3. In situ reflectometry trace of GaN template growth (Sample ID : UM-S07- 254). The highlighted areas correspond to important sub-steps during the epitaxy.2.1.1.1 High Temperature CleaningInitially, as the sample temperature is ramped up, the reflectivity increases due to the increase of the refractive index of the sample. Kim et al. has thoroughly studied the effect of initial thermal cleaning on the sapphire substrate andexperimentally demonstrated that this thermal treatment can effectively reduce the surface roughness of the substrate [46]. Generally, the flat surface is preferred for the GaN nuclei to be formed uniformly, which is critical to the crystal quality of the final GaN epilayer. The specific condition for the HT cleaning should be optimized by examining the treatment temperature and time. In our GaN growth, the optimal treatment temperature and time were set to be 1075 °C and 5 minutes, respectively. Moreover, HT surface annealing can effectively eliminate surface moisture.2.1.1.2 NitridationNitridation [5, 7] is the process of NH3 preflow under hydrogen (H2) ambient to prepare the surface for growth. During nitridation, NH3 reacts with the surface oxygen atoms on the sapphire substrate. Due to the replacement of the oxygen atoms by the nitrogen atoms and the diffusion of the nitrogen atoms into a certain depth, the exposed surface becomes a smooth amorphous state. Because this change of surface morphology is on the order of tens of angstrom, the corresponding reflectivity change is not significant. It has been shown that with a proper nitridation condition, GaN epilayers with lower dislocation density and better electrical and optical properties can be achieved [7]. However, as mentioned above, suitable combination of reactor conditions such as temperature, treatment time, and NH3 flow rate must be considered. In our GaN growth, the nitridation was optimized at 530 °C for a total of 210 seconds under 3 slm of NH3 flow.2.1.1.3 Low Temperature NucleationAs mentioned in Section 1.3.1, several approaches have been introduced to reduce the threading dislocation (TD) density in growing the GaN template. Specifically, the use of low temperature nucleation layer (LT NL) has been shown to be simple yet effective. A threading dislocation density as low as 108/cm2 has been reported [8].As GaN is nucleated on sapphire, the cubic phase islands are first formed at a temperature of 450 - 600 °C. These islands are subsequently transformed into the wurtzite phase [8]. The increase of the reflectivity during the LT NL growth is attributed to the increase of reflection from the flat top surfaces of nuclei. Basically, we know that the reflection from GaN is about twice stronger than that from sapphire due to the difference in refractive indices. As the islands become denser (i.e. the growth time of LT NL becomes longer), total reflection from the top surface of nuclei becomes up to 200% of reflection from sapphire substrate assuming that the entire surface is covered by GaN islands. Even though the islands are not coalesced completely to form a crystalline layer, this is still possible because the distances between the adjacent islands are too small compared to the optical wavelength. Once the reflectance exceeds twice that of the sapphire (as shown in Figure 2-3), the islands continue to coalesce further, which results in larger GaN grains and a thicker NL. Here, the size of the nucleation islands and the thickness of the NL are critical to obtain high quality GaN epilayer. To show that, we have compared a series of GaN templates with different NL conditions. All conditions were kept the same† except the growth time of the LT NL was varied,resulting in different LT NL thicknesses. The thickness of the LT NL was extrapolated by analyzing the reflectometry data as the reflection ratio at the end of LT NL growth to the sapphire substrate (RLT NL / RSapphire). The qualities of the GaN templates were characterized using photoluminescence (PL) and x-ray diffraction (XRD). From these results, the best GaN template quality can be obtained when RLT NL / RSapphire is around 2.6 which corresponds to a 40nm thick NL, at the given growth conditions.† LT NL growth temperature = 530°C, V/III = 9140, LT NL annealing time = 420 seconds, HT GaN growth temperature = 1040°C, V/III = 1230, growth time = 4300 seconds.Figure 2-4. The comparison of GaN template qualities with respect to the reflection ratio between the LT NL surface and the sapphire substrate.2.1.1.4 Annealing of Low Temperature Nucleation LayerIn GaN hetero-epitaxy with a large lattice mismatch, the initial growth on the surface follows the Volmer Weber model [47], i.e. GaN island growth dominates. In order to obtain smooth GaN templates, these islands need to be transformed into the layer-by-layer growth mode using an NL annealing process. During annealing, the substrate temperature is gradually increased up to around 1030 - 1050 °C under NH3 overpressure. Temperature ramping rate, reactor pressure, and NH3 flow can control the NL decomposition rate, which determines the surface roughness at the end of the annealing process [48, 49]. In Figure 2-3, after point (h) at which LT NL annealing begins, slight increase of reflectance is normally observed. The increase continues until around 800 °C at which GaN decomposition process starts to occur. Once the reflection intensity peaks, it begins to drop due to the increase in surface roughness. Initially randomly distributed islands start to be transformed into relatively uniform islands due to the decomposition of the NL and the migration of the gallium ad-atoms.During the annealing process, the reflectivity first decreases due to the increase of surface roughness. Further annealing results in a slight increase of reflectivity because at a higher temperature, the surface morphology becomes smoother. However, if we anneal the surface even further, the surface roughness increases again, which results in the decrease of reflection intensity [48, 49]. This phenomenon can be explained by considering the volume of the GaN islands. At the transition point ((k) in Figure 2-3), the volume of the islands per unit area becomes the highest which is preferable for the subsequent HT GaN growth. As a rule of thumb, the position of this (reflectometry trace) shoulder is dominated by the highest temperature of the annealing process [50]. In summary, the goal of the low temperature nucleation and the subsequent annealing is to achieve a surface morphology with proper density and sizes of the islands for the following HT GaN growth.As shown in Figure 2-5, even a slight change of the island distribution caused by a slight difference of the NL thickness and temperature ramping rate (Table 2-4) can result in a significant difference in the following HT GaN growth under the same conditions. In general, it takes longer for an NL with a rougher surface and smaller islands to be transformed into the 2D growth mode. The conditions to achieve high crystal quality GaN on sapphire are mostly related to the growth and annealing of the LT NL.2.1.1.5 HT GaN GrowthAs soon as the sapphire surface is covered with suitable volume, uniformity, thickness, and density of GaN islands, HT GaN growth can be followed. This HT GaN itself can be divided into two parts (Figure 2-6). Part I corresponds to the initial stage of HT GaN growth when the growth mode is transitioned from 3D to 2D, which affects the crystal quality significantly. In part II, GaN epilayer becomes thicker because the growth mode as well as growth condition is stabilized for 2Dmode. Several strategies to control the GaN growth in each regime will be briefly discussed in the following.The growth in part I is a buffer step to prepare a surface suitable for HT GaN growth. During this step, the oscillation of the reflectometry signal becomes increasingly obvious. Initially, the reflectivity continues to drop due to the increase of surface roughness induced by the coagulations of the islands, i.e. 3D growth. As time goes by, the 3D growth mode is suppressed and the 2D growth mode is enhanced. Once the surface becomes flattened due to the enhanced 2D growth, layer by layer growth of GaN begins, which causes the reflectivity to increase. The duration of this part of growth can be optimized by tweaking the reactor pressure, V/III ratio, and growth rate [51, 52]. For example, in the case of a low V/III ratio, it takes longer to recover the reflection intensity, which implies that the change of the growth mode (3D 2D) occurs more slowly. The reflectivity recovery time is critical to oscillation amplitude in part II. In general, a larger oscillation amplitude corresponds to a better crystal quality.The part II of the HT GaN growth is stable in a wide range of growth conditions because the growth occurs in a mass transfer limited region. Nevertheless, several key factors will still affect the crystalline structure, including the growth temperature, trimethyl-gallium (TMG) flow, NH3 flow, V/III ratio, and reactor pressure. As shown in Figure 2-7, the growth rate increases as the group III flow increases but decreases as the V/III ratio and growth temperature increase. The。

LED显示屏中英文对照外文翻译文献

LED显示屏中英文对照外文翻译文献

LED显示屏中英文对照外文翻译文献(文档含英文原文和中文翻译)译文:大屏幕显示系统的研究LED的发展随着计算机技术的高速发展,LED屏幕显示系统作为继电视、广播、报纸、杂志之后的“第五大媒体”正快速步入社会生活的各个方面。

它集微电子技术、计算机技术、信息处理技术于一体,可以将信息通过文字、图案、动画及视频四种形式显示出来。

与电视墙、磁翻板等媒体相比,LED大屏幕显示系统具有图案美观、色彩亮丽;图案、色彩变化丰富、快速;低功耗、长寿命、使用成本低、工作稳定可靠等特点。

它显示的图文视角大、视距远,因而已广泛应用于大型广场、商业广告、体育场馆、信息传播、新闻发布、证券交易;它还应用于工业控制和工业调动系统,便于把各种参数、报警点、工艺流程显示得更加清晰完美,可以满足不同环境的需要。

LED显示屏是一种利用计算机和复杂数字信号处理的电子广告宣传屏。

它的屏体部分由微处理器(主要是单片机)和驱动电路控制运行,显示的图像或文字由计算机编辑软件编辑获得。

由于LED显示屏这种新一代信息显示设备具有显示图案稳定、功耗低、寿命长等特点,而且它综合了各种信息显示设备的长处,并且克服了自身的不足,特别是由于一幅显示屏可以显示不同的内容,显示方式丰富。

所以在公共场合,它具有强烈的广告宣传和信息传递效果,日趋在固体显示中占主导地位。

LED显示屏的发展前景极为广阔,目前正朝着更高亮度、更高耐气候性、更高的发光密度、更高的发光均匀性、可靠性、全色化方向发展。

由不同材料的半导体组成能发出不同色彩的LED晶点。

目前应用最广的是红色、绿色、黄色LED。

而蓝色和纯绿色LED的开发已经达到了实用阶段。

LED显示屏的分类LED显示屏是多种技术综合应用的产品,涉及光电子学、半导体器件、数字电子电路、大规模集成电路、单片机及微机等各个方面,既有硬件又有软件。

LED 显示屏是作为广播、电视、报纸、杂志之后的又一新传播媒体。

目前LED显示屏根据使用场所不同,可以分为室外屏和室内屏两种,其主要区别是发光管的发光亮度不同。

点阵LED外文文献+翻译

点阵LED外文文献+翻译

基于AT89C52的LED概述LED(Light Emitting Diode),发光二极管,是一种固态的半导体器件,它可以直接把电转化为光。

LED的心脏是一个半导体的晶片,晶片的一端附在一个支架上,一端是负极,另一端连接电源的正极,使整个晶片被环氧树脂封装起来。

半导体晶片由两部分组成,一部分是P型半导体,在它里面空穴占主导地位,另一端是N型半导体,在这边主要是电子。

但这两种半导体连接起来的时候,它们之间就形成一个“P-N结”。

当电流通过导线作用于这个晶片的时候,电子就会被推向P区,在P区里电子跟空穴复合,然后就会以光子的形式发出能量,这就是LED发光的原理。

而光的波长也就是光的颜色,是由形成P-N结的材料决定的。

LED历史50年前人们已经了解半导体材料可产生光线的基本知识,第一个商用二极管产生于1960年。

LED是英文light emitting diode(发光二极管)的缩写,它的基本结构是一块电致发光的半导体材料,置于一个有引线的架子上,然后四周用环氧树脂密封,即固体封装,所以能起到保护内部芯线的作用,所以LED的抗震性能好。

发光二极管的核心部分是由P型半导体和N型半导体组成的晶片,在P 型半导体和N型半导体之间有一个过渡层,称为P-N结。

在某些半导体材料的PN结中,注入的少数载流子与多数载流子复合时会把多余的能量以光的形式释放出来,从而把电能直接转换为光能。

PN结施加反向电压时,少数载流子难以注入,故不发光。

这种利用注入式电致发光原理制作的二极管叫发光二极管,通称LED。

当它处于正向工作状态时(即两端加上正向电压),电流从LED阳极流向阴极时,半导体晶体就发出从紫外到红外不同颜色的光线,光的强弱与电流有关。

最初LED用作仪器仪表的指示光源,后来各种光色的LED在交通信号灯和大面积显示屏中得到了广泛应用,产生了很好的经济效益和社会效益。

以12英寸的红色交通信号灯为例,在美国本来是采用长寿命、低光效的140瓦白炽灯作为光源,它产生2000流明的白光。

LED中英文常用辞汇对照表之电路相关术语

LED中英文常用辞汇对照表之电路相关术语

LED中英文常用辭彙對照表之電路相關術語LEDinside為各位關心LED產業的人士整理了LED中英文常用辭彙對照表,前次推出的是LED中英文常用辭彙對照表之PCB相關術語,這次推出的是電路相關術語的中英對照。

以下是常用的相關術語表:背板 backplane機架chassis自舉Bootstrap滯回 Hysteresis反相Inverting抖動 jittery結點 Junction批號 Lot Number密勒 Miller節點node無鉛 Lead Free掉電 power down異相 Out of Phase上電Power up下拉 pull down上拉 pull up過沖 overshoot斜降ramp down斜升 ramp up振鈴 ringing基板substrate電信 Telecom閾值Threshold壓差dropout voltage縮放 scaling帶隙電壓參考Band gap voltage reference工作臺電源 benchtop supply方塊圖Block Diagram波特圖Bode Plot桶形電容bucket capcitor恒流源constant current source鐵芯飽和 Core Sataration交叉頻率crossover frequency紋波電流current ripple逐週期Cycle by Cycle週期跳步 cycle skipping死區時間 Dead Time核心溫度 DIE Temperature非使能,無效,禁用,關斷Disable主極點 dominant pole使能,有效,啟用Enable額定值 ESD Rating ESD評估板Evaluation Board下降沿 Failling edge品質因數 figure of merit浮充電壓float charge voltage反馳式功率級flyback power stage前向壓降forward voltage drop自由運行 free-running續流二極體 Freewheel diode滿負載 Full load柵極驅動gate drive柵極驅動級gate drive stage接地層 ground plane電感單位:亨利 Henry人體模式Human Body Model湧入電流 inrush current開爾文連接 Kelvin connection引腳框架Lead Frame電平移動 level-shift電源調整率Line regulation負載調整率 load regulation低壓差 Low Dropout非反相 Non-Inverting新穎的novel關斷狀態off state電源工作電壓 Operating supply voltage 輸出驅動級out drive stage產品型號 Part Number溝道MOSFETP-channel MOSFET P相位裕度 Phase margin開關節點 Phase Node可擕式電子設備 portable electronics電源正常 Power Good功率地Power Groud節電模式Power Save Mode逐脈衝(Pulse by Pulse) Pulse by Pulse冗餘二極體 redundant diode電阻分壓器 resistive divider紋波電流 ripple current上升沿 rising edge檢測電阻 sense resistor序列電源 Sequenced Power Supplys直通,同時導通 shoot-through雜散電感 stray inductances.子電路sub-circuit熱性能資訊 Thermal Information散熱片 thermal slug振盪電阻timing resistor線路,走線,引線Trace傳遞函數 Transfer function跳變點 Trip Point匝數比,=Np / Ns。

LED英文资料及中文翻译

LED英文资料及中文翻译

First LED SummaryLED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be directly converted into electricity to light. LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts, part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here is mainly electronic. But linking the two semiconductors, among them the formation of a "PN junction." When the current through the wires role in this chip, will be pushing e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon energy, and this is the principle of LED luminescence. The wavelength of light that is the color of light, is formed by the PN junction of the decisions of the material.Second LED history and development50 years ago, people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic performance LED good.LED is the core of the P-type semiconductor and components of the N-type semiconductor chips, the P-type semiconductor and N-type semiconductor between a transition layer, called the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it is not luminous. This use of injection electroluminescent diodes is produced by the principle of light-emitting diodes, commonly known as LED. When it in a positive state of the work (that is, at both ends with forward voltage), the current flows from the LED anode, cathode, semiconductor crystals on the issue from the ultraviolet to infrared light of different colors, light and the strength of the currents.Instruments used for the first LED light source instructions, but all kinds of light colored LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumileds companies have 18 red LED light source, including the loss of circuit, atotal power consumption of 14 watts to generate the same optical effect. Automotive LED lights is also the source of important areas.For general lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed, can be a white. Now, the InGaN / YAG white LED, YAG phosphor by changing the chemical composition of the phosphor layer and adjust the thickness of the3500-10000 K color temperature can be colored white. This blue LED through the method by white, constructed simple, low-cost, high technology is mature, so use the most.The development of LED display can be divided into the following phases: first phase 1990 to 1995, mainly monochrome and 16 color graphics screen. Used to display text and simple images, mainly used in railway stations, financial securities, banks, post offices and other public places, as public information display tools. The second stage is from 1995 to 1999, there have been 64, 256 level gray-scale two-color video screen. Video control technology, image processing, optical fiber communication technology applications will enhance the LED display to a new level. LED display control LSI chips special at this time developed by domestic companies, and can be applied. The third stage, from 1999, red, pure green, blue LED in bulk into China, while domestic enterprises in-depth research and development work, using red, green, and blue LED production of full-color display has been widely used , poured into sports stadiums, convention centers, squares and other public places, which will bring the domestic large-screen full-color era. With the rapid development of LED materials market, surface mount device is available from 2001, mainly used in indoor full color, and its high brightness, colorful, low temperature characteristics, the point spacing can be adjusted by different price Requirements were accepted, in just two years time, product sales have more than 300 million yuan, surface mount full-color LED display application market entered the new century. To meet the 2008 Olympic Games, "downsizing" plan, Liard developed a surface mount dual color displays, a lot of time for the training center and game scoring. Full color in Olympic venues, in order to tighten investment, full color way is mostly detachable, live during the Olympic Games as a tool can be used for rental after the event, as the performance of national policies such as public places, tools released by In this way cost recovery as soon as possible. On the market, China's accession to WTO, Beijing's successful Olympic bid and so on, into the development of LED display industry, a new opportunity. Domestic LED display market continues to grow, currently in the domestic market, domestic LED display market share of nearly 95%. LED display theinternational market capacity is expected to 30% a year growth rate. Currently, LED display manufacturers concentrated primarily in Japan, North America, China LED manufacturers in which the insignificant share of exports. According to incomplete statistics, the world, there are at least 150 manufacturers full color, in which products are complete, the larger company has some 30 or so.Third LED advantagesConductor light-emitting diode (LED) as a third-generation semiconductor lighting source. This fantastic product has a lot of advantages: (1) efficient light: spectra of almost all concentrated in the visible light frequency, the efficiency can reach 80% -90%. The luminous efficiency of incandescent visible light efficiency of almost 10% -20% only. (2) high quality of light: not as a result of spectrum UV and infrared, there is no heat, no radiation, is typically a green light illumination. (3) energy consumption of the small: single power generally 0.05-1w, through the cluster can be tailored to meet different needs, and waste very little. As a light source, under the brightness in the same power consumption of only ordinary incandescent 1/8-10.(4) long life: flux attenuation to 70% of the standard life expectancy is 100,000 hours.A semiconductor light can be used under normal circumstances 50 years, even if the long life of the people, life will be used up to two lights. (5) durable and reliable: No tungsten wire, glass and other easily damaged components, non-normal retirement rate is very small, very low maintenance costs. (6) the application of flexibility: small size, can flat pack, easy to develop into a short thin products, make point, line, face various forms of specific applications. (7) Security: working voltage 1.5-5v or less in between the current 20-70mA in between. (8) green: recyclable waste, no pollution, unlike fluorescent lamps containing mercury as ingredients. (9) response time is short: to adapt to frequent and high-frequency switching operation of occasions.Fourth Classification of LED display1, color by color can be divided intoSingle-color display: Single color (red or green).Two-color display: red and green dual-color, 256 gray scale levels, can display 65,536 colors.Full-color screen: red, green, blue color, 256 grayscale full color display can display more than 16 million kinds of colors.2, according to display device classificationLED Digital Display: 7 segment display devices for the digital control code, suitable for production of the clock screen, the interest rate screens, showing the number of electronic display.LED dot-matrix graphic display: display device is arranged by a number of uniform composition of the dot-matrix LED display modules, suitable for broadcast text, image information.LED video display: display devices are formed by a number of light-emitting diodes that can display video, animation and other video files.3, by using the occasion categoriesIndoor Display: LED spots smaller, general Φ3mm - Φ8mm, shows the general area of a few to more than ten square meters.Outdoor Display: dozens of square meters in size to several hundred square meters, high brightness, can work in the sun, with wind, rain, water resistant.4, classified according to light spot diameterIndoor screen: Φ3mm, Φ3.75mm, Φ5mm,Room external screen: Φ10mm, Φ12mm, Φ16mm, Φ19mm, Φ20mm, Φ21mm, Φ22mm, Φ26mmRoom external screen as the basic unit of light emitting tube, LED tube principle is a set of red, green, and blue light-emitting diode sealed in a plastic barrel and jointly develop5, Display a static, horizontal scroll, vertical scroll and flip display. One block module control drive 12 (up to control 24) 8X8 Dot Matrix, a total of 16X48 dot matrix (or 32X48 dot matrix), is a single block of MAX7219 (or PS7219, HD7279, ZLG7289 and 8279, and the like LED display driver module) 12 times (or 24 times)! Can use "cascade" approach the composition of any large dot matrix display. Effects, good power consumption, and the MAX7219 circuit than the use of lower cost.Fifth LED applicationsIt is a semiconductor light-emitting diode by controlling the display, which probably look like that from lots of small red lights are usually formed by the bright lights off to show character. Used to display text, graphics, images, animations, quotes, video, video signals and other information on the display screen.Graphic display and LED display into the video display by the LED matrix blocks. Graphic displays can be synchronized with the computer display Chinese characters, English text and graphics; video display using micro-computer control, graphics, images, and Mao, real-time, synchronization, clear message to the broadcast of a variety of information dissemination, but also shows two dimensional, three-dimensional animation, video, TV, VCD programs and live on. LED display shows the screen brightly colored, three-dimensional sense of strong, static, such as painting, moving as the film is widely used in finance, tax, business, telecommunications, sports, advertising, industrial enterprises, transport, education systems, stations, docks, airports, shopping malls, hospitals, hotels, banks, securities markets, construction market, auction houses, industrial enterprises in management and other public places.LED display can show changes in the numbers, text, graphics and video; not only can be used in the indoor environment can also be used for outdoor environment, with a projector, TV wall, LCD screen can not match advantage.Sixth LED screen test methodA look at Screen size, appearance, smoothness, with the screen connection and so onSecond look after the dead pixel screen light up, not in not within the scope of (in general the screen is basically gone now)Color consistency, display text is normal, display pictures, play full screen full color to white, red, green, and blue.一 LED概述LED(Light Emitting Diode),发光二极管,是一种固态的半导体器件,它可以直接把电转化为光。

led照明毕业论文中英文资料外文翻译文献

led照明毕业论文中英文资料外文翻译文献

led照明毕业论文中英文资料外文翻译文献Renewable and Sustainable Energy ReviewsHigh-brightness LEDs—Energy efficient lighting sources and their potential in indoor plant cultivation ABSTRACTThe rapid development of optoelectronic technology since mid-1980 has significantly enhanced the brightness and efficiency of light-emitting diodes (LEDs). LEDs have long been proposed as a primary light source for space-based plant research chamber or bioregenerative life support systems. The raising cost of energy also makes the use of LEDs in commercial crop culture imminent. With their energy efficiency, LEDs have opened new perspectives for optimizing the energy conversion and the nutrient supply both on and off Earth. The potentials of LED as an effective light source for indoor agriculturalproduction have been explored to a great extent. There are many researches that use LEDs to support plant growth in controlled environments such as plant tissue culture room and growth chamber. This paper provides a brief development history of LEDs and a broad base review on LED applications in indoor plant cultivation since 1990.Contents1. Introduction2. LED development.3. Color ratios and photosynthesis4. LEDs and indoor plant cultivation.4.1. Plant tissue culture and growth4.2. Space agriculture84.3. Algaculture4.4. Plant disease reduction5. Intermittent and photoperiod lighting and energy saving6. Conclusion1. IntroductionWith impacts of climate change, issues such as more frequent and seriousdroughts, floods, and storms as well as pest and diseases are becoming more serious threats to agriculture. These threats along with shortage of food supply make people turn to indoor and urban farming (such as vertical farming) for help. With proper lighting, indoor agriculture eliminates weather-related crop failures due to droughts and floods to provide year-round crop production, which assist in supplying food in cities with surging populations and in areas of severe environmental conditions.The use of light-emitting diodes marks great advancements over existing indoor agricultural lighting. LEDs allow the control of spectral composition and the adjustment of light intensity to simulate the changes of sunlight intensity during the day. They have the ability to produce high light levels with low radiant heat output and maintain useful light output for years. LEDs do not contain electrodes and thus do not burn out like incandescent or fluorescent bulbs that must be periodically replaced. Not to mention that incandescent and fluorescent lamps consume a lot of electrical power while generating heat, which must be dispelled from closed environments such as spaceships and space stations.2. LED developmentLED is a unique type of semiconductor diode. It consists of a chip of semiconductor material doped with impurities to create a p–n junction. Current flows easily from the p-side (anode), to the n-side (cathode), but not in the reverse direction.Electrons and holes flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon. The color (wavelength) of the light emitted depends on the band gap energy of the materials forming the p–n junction. The materials used for an LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.The key structure of an LED consists of the die (or light-emitting semiconductor material), a lead frame where the die is placed, and the encapsulation which protects the die (Fig. 1).Fig.1LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have made possible the production of devices with ever-shorter wavelengths, producing light in a variety of colors. J.Margolin reported that the first known light-emitting solid state diode was made in 1907 by H. J. Round. No practical use of Round’s diode was made for several decades until the invention of the first practical LED by Nick Holonyak, Jr in 1962. His LEDs became commercially available inlate 1960s. These GaAsP LEDs combine three primary elements: gallium, arsenic and phosphorus to provide a 655nm red light with brightness levels of approximately 1–10 mcd at 20mA. As the luminous intensity was low, these LEDs were only used in a few applications, primarily as indicators. Following GaAsP, GaP (gallium phosphide) red LEDs were developed. These device sex hibit very high quantum efficiencies at low currents. As LED technology progressed through the 1970s, additional colors and wavelengths became available. The most common materials were GaP green and red, GaAsP orange, and high efficiency red and GaAsP yellow. The trend towards more practical applications (such as in calculators, digital watches, and test equipment) also began to develop. As the LED materials technology became more advanced, the light output was increased, and LEDs became bright enough to be used for illumination.In 1980s a new material, GaAlAs (gallium aluminum arsenide) was developed followed by a rapid growth in the use of LEDs. GaAlAs technology provides superiorperformance over previously available LEDs. The voltage requirement is lower, which results in a total power savings. LEDs could be easily pulsed or multiplexed and thus are suitable for variable message and outdoor signs. Along this development period, LEDs were also designed into bar code scanners, fiber optic data transmission systems, and medicalequipment. During this time, the improvements in crystal growth and optics design allow yellow, green and orange LEDs only a minor improvement in brightness and efficiency. The basic structure of the material remained relatively unchanged.As laser diodes with output in the visible spectrum started to commercialize in late 1980s, LED designers used similar techniques to produce high-brightness and high reliability LEDs. This led to the development of InGaAlP (indium gallium aluminum phosphide) visible light LEDs. Via adjusting the energy band gap InGaAlP material can have different color output. Thus, green, yellow, orange and red LEDs could all be produced using the same basic technology. Also, light output degradation of InGaAlP material is significantly improved.Shuji Nakamura at Nichia Chemical Industries of Japan introduced blue LEDs in 1993. Blue LEDs have always been difficult to manufacture because of their high photon energies (>2.5 eV) and relatively low eye sensitivity. Also, the technology to fabricate these LEDs is very different and less advanced than standard LED materials. But blue is one of the primary colors (the other two being red and green). Properly combining the red, green, and blue light is essential to produce white and full-color. This process requires sophisticated software and hardware design to implement. In addition, the brightness level is low and the overall light output of each RGB die being used degrades at a different rate resulting in an eventual color unbalance. The blue LEDs available today consist of GaN (gallium nitride) and SiC (silicon carbide) construction. The blue LED that becomes available in production quantities has result in an entire generation of new applications that include telecommunications products, automotive applications, traffic control devices, and full-color message boards. Even LED TVs can soon become commercially available.Compare to incandescent light’s 1000-h and fluorescent light’s 8000-h life span, LEDs have a very significantly longer life of 100,000 h. In addition to their long life, LEDs have many advantages over conventional light source. These advantages include small size, specific wavelength, low thermal output, adjustable light intensity and quality, as well as high photoelectric conversion efficiency. Such advantages make LEDs perfect for supporting plant growth in controlled environment such as plant tissue culture room and growth chamber. Table 1 is a list of some common types of LEDs as compiled from .The chlorophyll molecules in plants initiate photosynthesis bycapturing light energy and converting it into chemical energy to help transforming water and carbon dioxide into the primary nutrient for living beings. The generalized equation for the photosynthetic process is given as:CO2 + H2O—light—>(CH2O)+ O2where (CH2O) is the chemical energy building block for thesynthesis of plant components.Chlorophyll molecules absorb blue and red wavelengths most efficiently. The green and yellow wavelengths are reflected or transmitted and thus are not as important in the photosyntheticprocess. That means limit the amount of color given to the plants and still have them grow as well as with white light. So, there is no need to devote energy to green light when energy costs are aconcern, which is usually the case in space travel.The LEDs enable researchers to eliminate other wavelengths found within normal white light, thus reducing the amount of energy required to power the plant growth lamps. The plants grow normally and taste the same as those raised in white light.Red and blue light best drive photosynthetic metabolism. These light qualities are particularly efficient in improving the developmental characteristics associated with autotrophic growth habits. Nevertheless, photosynthetically inefficient light qualities also convey important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses. In addition, photoperiod (the adjustment of light and dark periods) and light quality (the adjustment of red, blue and far-red light ratio) also have decisive impacts on photomorphogenesis.The superimposed pattern of luminescence spectrum of blue LED (450–470 nm) and that of red LED (650–665 nm) corresponds well to light absorption spectrum of carotenoids and chlorophyll. Various plant cultivation experiments are possible when these twokinds of LED are used with the addition of far-red radiation (730–735 nm) as the light source. Along the line of the LED technology advancement, LEDs become a prominent light source for intensive plant culture systems and photobiological researches. The cultivation experiments which use such light sources are becoming increasingly active. Plant physiology and plant cultivation researches using LEDs started to peak in 1990s and become inevitable in the new millennium. Those researches have confirmed that LEDs are suitable for cultivation of a variety of algae,crop, flower, fruit, and vegetable.Some of the pioneering researches are reviewed in the followings.Bula et al. have shown that growing lettuce with red LEDs in combination with blue tubular fluorescent lamp (TFL) is possible. Hoenecke et al. have verified the necessity of blue photons for lettuce seedlings production by using red LEDs with blue TFL. As the price of both blue and red LEDs have dropped and the brightness increased significantly, the research findings have been able to be applied in commercial production. As reported by Agence France Press, Cosmo Plant Co., in Fukuroi, Japan has developed a red LED-based growth process that uses only 60% of electricity than a fluorescent lighting based one.Tennessen et al. have compared photosynthesis from leaves of kudzu (Pueraria lobata) enclosed in a leaf chamber illuminated by LEDs versus by a xenon arc lamp. The responses of photosynthesis to CO2 are similar under the LED and xenon arc lamps at equal photosynthetic irradiance. There is no statistical significant difference between the white light and red light measurements in high CO2. Some leaves exhibited feedback inhibition of photosynthesis which is equally evident under irradiation of either lamp type. The results suggest that photosynthesis research including electron transport, carbon metabolismand trace gas emission studies should benefit greatly from the increased reliability, repeatability and portability of a photosynthesis lamp based on LEDs.Okamoto et al. have investigated the effects of different ratios of red and blue (red/blue) photosynthetic photon flux density (PPFD) levels on the growth and morphogenesis of lettuce seedlings. They have found that the lettuce stem length decreases significantly with an increase in the blue PPFD. The research has also identified the respective PPFD ratio that (1) accelerates lettuce seedlings’stem elongation, (2) maximizes the whole plant dry weight, (3) accelerates the growth of whole plants, and (4) maximizes the dry weights of roots and stems. Photosynthesis does not need to take place in continuous light. The solid state nature allows LEDs to produce sufficient photon fluxes and can be turned fully on and off rapidly (200 ns), which is not easily achievable with other light sources. This rapid on–off feature has made LEDs an excellent light source for photosynthesis research such as pulsed lighting for the study of photosynthetic electron transport details. The off/dark period means additional energy saving on top of the LEDs’low power consumption.4. LEDs and indoor plant cultivation4.1. Plant tissue culture and growthTissue culture (TC), used widely in plant science and a number of commercial applications, is the growth of plant tissues or cells within a controlled environment, an ideal growth environment that is free from the contamination of microorganisms and other contaminants. A controlled environment for PTC usually means filtered air, steady temperature, stable light sources, and specially formulated growth media (such as broth or agar). Micropropagation, a form of plant tissue culture (PTC), is used widely in forestry and floriculture. It is also used for conserving rare or endangered plant species. Other uses of PTC include:1short-term testing of genetic constructions or regeneration oftrans genic plants,2 cross breeding distantly related species and regeneration of the novel hybrid,3 screening cells for advantageous characters (e.g. herbicidere sistance/tolerance),4embryo rescue (i.e. to cross-pollinate distantly related specie sand then tissue culture there sulting embryo which would normally die),5 large-scale growth of plant cells in liquid culture inside bioreactors as a source of secondary products (like recombinant proteins used as biopharmaceuticals).6production of doubled monoploid plants from haploid cultures to achieve homozygous lines more rapidly in breeding programs (usually by treatment with colchicine which causes doubling of the chromosome number).Tissue culture and growth room industries have long been using artificial light sources for production. These light sources include TFL, high pressure sodium lamp (HPS), metal halide lamp (MHL) and incandescent lamp, etc. Among them, TFL has been the most popular in tissue culture and growth room industries. However, the use of TFL consumes 65% of the total electricity in a tissue culture lab. That is the highest non-labor costs. As a result, these industries continuously seek for more efficient light sources. The development of high-brightness LED has made LED a promising light source for plant growth in controlled environments.Nhut et al. have cultured strawberry plantlets under different blue to red LED ratios as well as irradiation levels and compared its growth to that under plant growth fluorescent. The results suggest that a culture system using LED is advantageous for the micropropagation of strawberry plantlets. The study also demonstrates that the LED light source for in vitro culture of plantlets contributes to an improved growth of the plants in acclimatization.Brown et al. have measured the growth and dry matter partitioning of ‘Hungarian Wax’pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation. Pepper biomass reduces when grown under red LEDs without blue wavelengths compared to plants grown under supplemental blue fluorescent lamps. The addition of far-red radiation results in taller plants with greater stem mass than red LEDs alone. Fewer leaves developed under red or red plus far-red radiation than with lamps producing blue wavelengths. The results of their research indicate that with proper combination of other wavelengths, red LEDs may be suitable for the culture of plants in tightly controlled environments.4.2. Space agricultureBecause re-supply is not an option, plants are the only options to generate enough food, water and oxygen to help make future explorers self-sufficient at space colonies on the moon, Mars or beyond. In order to use plants, there must be a light source. Standard light sources that used in homes and in greenhouses and in growth chambers for controlled agriculture here on Earth are not efficient enough for space travel. While a human expedition outside Earth orbit still might be years away, the space farming efforts are aimed at developing promising artificial light sources. LEDs, because of their safety, small mass and volume, wavelength specificity, and longevity, have long been proposed as a primary light source for space-base plant research chamber or bioregenerative life support systems .Infrared LEDs that are used in remote controls devices have other uses. Johnson et al. have irradiated oat (Avena sativa cv Seger) seedlings with infrared (IR) LED radiation passed through a visible-light-blocking filter. The irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. This suggests that the oat seedlings are able to detect IR LED radiation. These findings also expand the defined range of wavelengths involved in radiation–gravity (light–gravity) interactions to include wavelengths in the IR region of the spectrum.Goins et al. grow wheat under red LEDs and compare them to the wheat grown under (1) white fluorescent lamps and (2) red LEDs supplemented with blue light from blue fluorescent lamps. The results show that wheat grown under red LEDs alone displayed fewer subtillers and a lower seed yield compared to those grown under white light. Wheat grown under red LEDs + 10% BF light had comparable shoot dry matter accumulation and seed yield relative to those grown under white light. These results indicate that wheat can complete its life cycle under red LEDs alone, but larger plants and greater amounts of seed are produced in the presence of red LEDs supplemented with a quantity of blue light.The research of Goins and his team continues in plant growth chambers the size of walk-in refrigerators with blue and red LEDs to grow salad plants such as lettuce and radishes. They hope the plant growth chamber would enable space station staff to grow and harvest salad greens, herbs and vegetables during typical fourmonth tours on the outpost .4.3. AlgacultureAlgaculture, refers to the farming of species of algae, has been a great source for feedstock, bioplastics, pharmaceuticals, algae fuel, pollution control, as well as dyes and colorants. Algaculture also provides hopeful future food sources.Algae can be grown in a photobioreactor (PBR), a bioreactor which incorporates some type of light source. A PBR is a closed system, as opposed to an open tank or pond. All essential nutrients must be introduced into the system to allow algae to grow and be cultivated. A PBR extends the growing season and allows growing more species. The device also allows the chosen species to stay dominant. A PBR can either be operated in ‘‘batch mode’’or ‘‘continuous mode’’in which a continuous stream of sterilized water that contains air, nutrients, and carbon dioxide is introduced. As the algae grows, excess culture overflows and is harvested.When the algae grow and multiply, they become so dense that they block light from reaching deeper into the water. As a result, light only penetrates the top 7–10 cm of the water in most algalcultivation systems. Algae only need about 1/10 the amount of direct sunlight. So, direct sunlight is often too strong for algae. A means of supplying light to algae at the right concentration is to place the light source in the system directly.Matthijs et al. have used LEDs as the sole light source in continuous culture of the green alga (Chlorella pyrenoidosa). The research found the light output of the LED panel in continuous operation sufficient to support maximal growth. Flash operation at 5-ps pulse ‘‘on’’ duration between dark periods of up to 45 ps would stillsustain near maximum growth. While longer dark periods tend to cut the growth rate, the light flux decrease resulting from such operation does not reduce the growth as much as that of the similar flux decrease in continuous operation. Their research concludes that the use of flashing LEDs (which means intermittent light) in indoor algal culture yielded a major gain in energy economy comparing to fluorescent light sources. An additional advantage is that heat waste losses are much smaller. The most interesting discovery of this study may be that adding blue light to the red LED light did not change the growth properties.In order to take advantage of the biotechnological potential of algae, Lee and Palsson have calculated theoretical values of gas mass transfer requirements and light intensity requirements to support high-density algal cultures for the 680 nm monochromatic red light from LED as a light source. They have also designed a prototype PBR based on these calculations. Using on-line ultra filtration to periodically provide fresh medium, these researchers have achieved a cell concentration of more than 2×109cells/ml (more than 6.6%, vol/vol), cell doubling times as low as 12 h, and an oxygen production rate as high as 10 mmol oxygen/l culture/h. This research indicates that the development of a small LED-based algal photobioreactors is economically achievable.Another research of algae via LEDs is conducted by Nedbal et al. Their research is a study of light fluctuation effects on a variety of algae in dilute cultures using arrays of red LEDs to provide intermittent and equivalent continuous light in small-size (30 ml) bioreactors. The results endorse that the algae growth rates in certain calculated intermittent light can be higher than the growth rate in the equivalent continuous light. Yanagi and Okamoto has grown five spinach plants under the red LEDs and another five under 40W plant growth fluorescent lamps at the same light intensity of 125 mmol/m2/s. The dry matter production under the LEDs is slightly less than that under the fluorescent lamps. The plant leaf area under the red LEDs is also smaller than that under the fluorescent lamps. Nevertheless, they reach a conclusion that LEDs can qualify as an artificial light source for plant growth.4.4.Plant disease reductionSchuerger and Brown have used LED arrays with different spectral qualities to determine the effects of light on the development of tomato mosaic virus (ToMV) in peppers and powdery mildew on cucumbers. Their research concludes that spectral quality may alter plant disease development. Latter research regarding bacterial wilt on tomato has confirmed this conclusion and demonstrates that spectral quality may be useful as a component of an integrated pest management program for space-based ecological life support systems. Schuerger et al. have shown that the spectral quality effects on peppers’ anatomical changes in stem and leaf tissues are corr elated to the amount of blue light in primary light source.Miyashita et al. use red LEDs (peak wavelength: 660 nm) and white fluorescent lamps as light sources for potato plantlets growth in vitro. They found that shoot length and chlorophyll concentration of the plantlets increases with increasing 630–690 nm red photon flux (R-PF) while there are no significant differences in dry weight and leaf area of the plantlets with different R-PF levels. This means red lightaffects the morphology rather than the growth rate of potato plantlets in vitro. As a result, they suggest that red LEDs can be used for controlling plantlet morphology in micropropagation.5. Intermittent and photoperiod lighting and energy savingTime constants for photosynthetic processes can be divided into three ranges: primary photochemistry, electron shuttling, and carbon metabolism. These three photosynthetic processes can be uncoupled by providing pulses of light within the appropriate range for each process. At high frequencies, pulsing light treatments can be used to separate the light reactions (light harvesting and charge separation) from the dark reactions (electron shuttling) of photosynthetic electron transport. LEDs’ flexible pulsating ability can be coupled with such characteristics of photosynthesis and lead to additional energy saving.Tennessen et al. use LEDs to study the effects of light pulses (micro- to milli-second) of intact tomato leaves. They found that when the equivalent of 50 mmol photons mp -2s-1 is provided during 1.5 ms pulses of 5000 mmol photons mp -2s-1 followed by 148.5 ms dark periods, photosynthesis is the same as in continuous 50 mmol photons mp -2s-1 . Data support the theory that photons in pulses of 100 ps or shorter are absorbed and stored in the reaction centers to be used in electron transport during the dark period. Pigments of the xanthophyll cycle were not affected by pulsed light treatments. This research suggests that, instead of continuous light, using effectively calculated intermittent light (which means less energy consumption) might not affect the plant production.Jao and Fang have investigated the effects of intermittent light on growth of potato plantlets in vitro. They also use conventional TFLs for the experiment to explore the electrical savings realized by adjusting the frequency and duty ratio of LEDs. TFLs provide continuous fluctuating light at 60 Hz while LEDs provide nonfluctuating light and pulse light of the preset frequency and duty ratio. When the growth rate is the only concern, LEDs at 720 Hz (1.4 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod stimulated plant growth the most. When energy consumption is the major concern, using LEDs at 180 Hz (5.5 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod would not significantly sacrifice plant growth, especially when energy for heat removal is also taken into account.6. ConclusionsThe first sustained work with LEDs as a source of plant lighting occurred in the mid-1980s when a lighting system for plant growth was designed for space shuttles and space stations for it is realized that people cannot go to the Moon, Mars, or beyond without first mastering the art of indoor farming on Earth. As the performance of LED continues to improve, these lighting systems progress from red only LED arrays using the limited components available to high-density, multi-color LED chip-on-board technologies. Today, space age gardeners who have been testing high-efficiency light sources for future space colonists have identified energy efficient LEDs as the major light source not only to grow food but also to generate and purify oxygen and water—key sustainers of human life. The removal of carbon dioxide from a closed environment is another added benefit.LEDs are the first light source to provide the capability of true spectral composition control, allowing wavelengths to match to plant photoreceptors to optimize production as well as to influence plant morphology and composition. They are easily integrated into digital control systems, facilitating complex lighting programs like varying spectral composition over the course of a photoperiod or with plant development stage. LEDs do not contain mercury. They are safer to operate than current lamps since they do not have glass envelopes or high touch temperatures.While the process of photosynthesis does not require continuous light of full spectrum, LEDs can produce sufficient photon fluxes of specific wavelength on and off rapidly. Such mechanism of photosynthesis coupled with the solid state characteristics of LEDs constitute two ways of energy saving (cutting out unnecessary spectrum segment and turning off the light periodically) on top of the LEDs’ low power consumption. These are not easily achievable with other light sources.This paper provides a broad base review on LED applications in horticulture industry since 1990. These researches pave the way for the researches of similar types using different species and lead to comparable conclusion that LEDs are well qualified to replace its more energy demanding counterparts as controlled environment light source for agricultural research such as providing tissue culture lighting as well as supplemental and photoperiod lighting for greenhouses.With the energy it can save, LED’s becoming ec onomically feasible in large-scale indoor farming lighting applications is just around the corner.再生可持续能源评论高亮高效节能LED灯的来源及其在室内植物栽培中的潜力摘要自1980年中期以来,光电子技术的迅猛发展,显著调高了发光二极管(LED)的亮度和效率。

LED英文资料及中文翻译

LED英文资料及中文翻译

First LED SummaryLED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be directly converted into electricity to light. LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts, part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here is mainly electronic. But linking the two semiconductors, among them the formation of a "PN junction." When the current through the wires role in this chip, will be pushing e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon energy, and this is the principle of LED luminescence. The wavelength of light that is the color of light, is formed by the PN junction of the decisions of the material.Second LED history and development50 years ago, people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic performance LED good.LED is the core of the P-type semiconductor and components of the N-type semiconductor chips, the P-type semiconductor and N-type semiconductor between a transition layer, called the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it is not luminous. This use of injection electroluminescent diodes is produced by the principle of light-emitting diodes, commonly known as LED. When it in a positive state of the work (that is, at both ends with forward voltage), the current flows from the LED anode, cathode, semiconductor crystals on the issue from the ultraviolet to infrared light of different colors, light and the strength of the currents.Instruments used for the first LED light source instructions, but all kinds of light colored LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumileds companies have 18 red LED light source, including the loss of circuit, atotal power consumption of 14 watts to generate the same optical effect. Automotive LED lights is also the source of important areas.For general lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed, can be a white. Now, the InGaN / YAG white LED, YAG phosphor by changing the chemical composition of the phosphor layer and adjust the thickness of the3500-10000 K color temperature can be colored white. This blue LED through the method by white, constructed simple, low-cost, high technology is mature, so use the most.The development of LED display can be divided into the following phases: first phase 1990 to 1995, mainly monochrome and 16 color graphics screen. Used to display text and simple images, mainly used in railway stations, financial securities, banks, post offices and other public places, as public information display tools. The second stage is from 1995 to 1999, there have been 64, 256 level gray-scale two-color video screen. Video control technology, image processing, optical fiber communication technology applications will enhance the LED display to a new level. LED display control LSI chips special at this time developed by domestic companies, and can be applied. The third stage, from 1999, red, pure green, blue LED in bulk into China, while domestic enterprises in-depth research and development work, using red, green, and blue LED production of full-color display has been widely used , poured into sports stadiums, convention centers, squares and other public places, which will bring the domestic large-screen full-color era. With the rapid development of LED materials market, surface mount device is available from 2001, mainly used in indoor full color, and its high brightness, colorful, low temperature characteristics, the point spacing can be adjusted by different price Requirements were accepted, in just two years time, product sales have more than 300 million yuan, surface mount full-color LED display application market entered the new century. To meet the 2008 Olympic Games, "downsizing" plan, Liard developed a surface mount dual color displays, a lot of time for the training center and game scoring. Full color in Olympic venues, in order to tighten investment, full color way is mostly detachable, live during the Olympic Games as a tool can be used for rental after the event, as the performance of national policies such as public places, tools released by In this way cost recovery as soon as possible. On the market, China's accession to WTO, Beijing's successful Olympic bid and so on, into the development of LED display industry, a new opportunity. Domestic LED display market continues to grow, currently in the domestic market, domestic LED display market share of nearly 95%. LED display theinternational market capacity is expected to 30% a year growth rate. Currently, LED display manufacturers concentrated primarily in Japan, North America, China LED manufacturers in which the insignificant share of exports. According to incomplete statistics, the world, there are at least 150 manufacturers full color, in which products are complete, the larger company has some 30 or so.Third LED advantagesConductor light-emitting diode (LED) as a third-generation semiconductor lighting source. This fantastic product has a lot of advantages: (1) efficient light: spectra of almost all concentrated in the visible light frequency, the efficiency can reach 80% -90%. The luminous efficiency of incandescent visible light efficiency of almost 10% -20% only. (2) high quality of light: not as a result of spectrum UV and infrared, there is no heat, no radiation, is typically a green light illumination. (3) energy consumption of the small: single power generally 0.05-1w, through the cluster can be tailored to meet different needs, and waste very little. As a light source, under the brightness in the same power consumption of only ordinary incandescent 1/8-10.(4) long life: flux attenuation to 70% of the standard life expectancy is 100,000 hours.A semiconductor light can be used under normal circumstances 50 years, even if the long life of the people, life will be used up to two lights. (5) durable and reliable: No tungsten wire, glass and other easily damaged components, non-normal retirement rate is very small, very low maintenance costs. (6) the application of flexibility: small size, can flat pack, easy to develop into a short thin products, make point, line, face various forms of specific applications. (7) Security: working voltage 1.5-5v or less in between the current 20-70mA in between. (8) green: recyclable waste, no pollution, unlike fluorescent lamps containing mercury as ingredients. (9) response time is short: to adapt to frequent and high-frequency switching operation of occasions.Fourth Classification of LED display1, color by color can be divided intoSingle-color display: Single color (red or green).Two-color display: red and green dual-color, 256 gray scale levels, can display 65,536 colors.Full-color screen: red, green, blue color, 256 grayscale full color display can display more than 16 million kinds of colors.2, according to display device classificationLED Digital Display: 7 segment display devices for the digital control code, suitable for production of the clock screen, the interest rate screens, showing the number of electronic display.LED dot-matrix graphic display: display device is arranged by a number of uniform composition of the dot-matrix LED display modules, suitable for broadcast text, image information.LED video display: display devices are formed by a number of light-emitting diodes that can display video, animation and other video files.3, by using the occasion categoriesIndoor Display: LED spots smaller, general Φ3mm - Φ8mm, shows the general area of a few to more than ten square meters.Outdoor Display: dozens of square meters in size to several hundred square meters, high brightness, can work in the sun, with wind, rain, water resistant.4, classified according to light spot diameterIndoor screen: Φ3mm, Φ3.75mm, Φ5mm,Room external screen: Φ10mm, Φ12mm, Φ16mm, Φ19mm, Φ20mm, Φ21mm, Φ22mm, Φ26mmRoom external screen as the basic unit of light emitting tube, LED tube principle is a set of red, green, and blue light-emitting diode sealed in a plastic barrel and jointly develop5, Display a static, horizontal scroll, vertical scroll and flip display. One block module control drive 12 (up to control 24) 8X8 Dot Matrix, a total of 16X48 dot matrix (or 32X48 dot matrix), is a single block of MAX7219 (or PS7219, HD7279, ZLG7289 and 8279, and the like LED display driver module) 12 times (or 24 times)! Can use "cascade" approach the composition of any large dot matrix display. Effects, good power consumption, and the MAX7219 circuit than the use of lower cost.Fifth LED applicationsIt is a semiconductor light-emitting diode by controlling the display, which probably look like that from lots of small red lights are usually formed by the bright lights off to show character. Used to display text, graphics, images, animations, quotes, video, video signals and other information on the display screen.Graphic display and LED display into the video display by the LED matrix blocks. Graphic displays can be synchronized with the computer display Chinese characters, English text and graphics; video display using micro-computer control, graphics, images, and Mao, real-time, synchronization, clear message to the broadcast of a variety of information dissemination, but also shows two dimensional, three-dimensional animation, video, TV, VCD programs and live on. LED display shows the screen brightly colored, three-dimensional sense of strong, static, such as painting, moving as the film is widely used in finance, tax, business, telecommunications, sports, advertising, industrial enterprises, transport, education systems, stations, docks, airports, shopping malls, hospitals, hotels, banks, securities markets, construction market, auction houses, industrial enterprises in management and other public places.LED display can show changes in the numbers, text, graphics and video; not only can be used in the indoor environment can also be used for outdoor environment, with a projector, TV wall, LCD screen can not match advantage.Sixth LED screen test methodA look at Screen size, appearance, smoothness, with the screen connection and so onSecond look after the dead pixel screen light up, not in not within the scope of (in general the screen is basically gone now)Color consistency, display text is normal, display pictures, play full screen full color to white, red, green, and blue.一 LED概述LED(Light Emitting Diode),发光二极管,是一种固态的半导体器件,它可以直接把电转化为光。

点阵LED外文翻译3000字文献

点阵LED外文翻译3000字文献

Based on AT89C52 LED overviewLED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be directly converted into electricity to light. LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts, part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here is mainly electronic. But linking the two semiconductors, among them the formation of a "PN junction." When the current through the wires role in this chip, will be pushing e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon energy, and this is the principle of LED luminescence. The wavelength of light that is the color of light, is formed by the PN junction of the decisions of the material.LED history 50 years ago, people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic performance LED good.LED is the core of the P-type semiconductor and components of the N-type semiconductor chips, the P-type semiconductor and N-type semiconductor between a transition layer, called the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it is not luminous. This use of injection electroluminescent diodes is produced by the principle of light-emitting diodes, commonly known as LED. When it in a positive state of the work (that is, at both ends with forward voltage), the current flows from the LED anode, cathode, semiconductor crystals on the issue from the ultraviolet to infrared light of different colors, light and the strength of the currents.Instruments used for the first LED light source instructions, but all kinds of light colored LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumileds companies have 18 red LED light source, including the loss of circuit, a total power consumption of 14 watts to generate the same optical effect. Automotive LED lights is also the source of important areas.For general lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed, can be a white. Now, the InGaN / YAG white LED, YAG phosphor by changing the chemical composition of the phosphor layer and adjust the thickness of the 3500-10000 K color temperature can be colored white. This blue LED through the method by white, constructed simple, low-cost, high technology is mature, so use the most.In the 1960s, the use of science and technology workers semiconductor PN junction of The principle of developing a LED light-emitting diodes. At that time, the development of LED, the materials used are GaASP, its luminous color is red. After nearly 30 years of development, and now we are very familiar with the LED, has been sent to red, orange, yellow, green, blue, and other shade. However lighting necessary for white LED light only in recent years to develop, readers here to tell us about lighting with white LED.The LED display screen and video display into the text by LED matrix blocks. Graphic display can be displayed with computer, English, Chinese text and graphics, Video screen using microcomputer control, graphic, image, with real-time, synchronization, clear information dissemination way play all kinds of information, but also shows 2d, 3d animation, videos, TV, VCD programs and live. The LED display screen display bright colors, stereo sense is strong, such as oil, such as films, widely used in finance, taxation, industry and commerce, telecommunications, sports, advertising, corporations, transportation, education system, station, port, airport, hospital, shopping malls, hotels, Banks, securities market, market, and construction management of industrial enterprises, Christie's and other public places.The LED display can display the change of digital image; text, graphics, Not only can be used for indoor environment can also be used in outdoor environment, projectors, LCD TV wall, and the incomparable advantages.LED by the wide attention and rapid development, and it is the advantages of itself. These advantages in is: high brightness, working voltage, low consumption, miniaturization, impact resistance and long service life and stable performance. LED the development prospect, is currently towards a higher brightness, higher resistance to climate, higher and higher light shine density evenness, reliability, the direction of development. Full-colorThe classification of the LED display1, the color can be divided into gezerThe single color display: single colors (red or green).Double colors: red and green screen, double colors gray, can show 256 levels 65536 colors.Full-color display: red, green, and blue, gray level 256 gezer full-color display screen can show more than 1,600 colors.2, according to the classification of display devicesLED digital display: display device for seven yards, suitable for making the clock display screen, interest rates, digital electronic display screen.Pictures of LED dot matrix LCD display device is composed of many: evenly composed of light emitting diode matrix display module, suitable for broadcast text, images of information.LED video display: display device is composed by many light-emitting diodes, video, animation shows various video files.3, by using occasions classificationIndoor display: light point is lesser, general Φ 3mm - Φ 8mm, display area of general several ten square meters to.Outdoor screen area to several hundred square meters general dozens, high brightness, can work under the sun, in the wind, rain, waterproof function.4 points, according to the classification of light in diameterIndoor screens: Φ 3mm, Φ 3.75 mm, Φ 5mm,Outdoor screen: Φ 10mm, Φ 12mm and Φ 16mm Φ, 19mm, Φ 20mm, Φ 21mm, Φ 22mm, Φ 26mmThe basic unit of the light outdoor screen for led light cone tube, the principle is a group of red, green, and blue light emitting diode sealed in a plastic tube in common5. Display horizontally scrolling, static, vertical scroll and flip shows, etc. Single block module control drive 12 (maximum control and block), 16X48 matrix 8X8 matrix (or 32X48 matrix), is a single block of MAX7219 (or PS7219, HD7279, ZLG7289 8279 and other similar LED display driver module) 12 times (or 24 times)! Can use "cascade" means any bitmap big screen composed. Show good effect, low consumption, and the cost of using MAX7219 circuit is lower.The LED display inspection method,See appearance, specifications, screen body flatness, screen the attachment within2 look bad, after the light screen is not in scope, the screen (generally now basically no)Color consistency, displays text display is normal, the picture to screen, full-color play white, red, green and blue.Technical advantageExisting common indoor full-color scheme comparison:1 the matrix modules: design, color dot matrix LCD by indoor artifactsAdvantage: the cost of raw materials, production and processing of the most advantage of simple process, quality is stable.Faults: color consistency, Mosaic phenomenon, serious effect.2. Single lamp schemes for solving the bitmap screen color: for outdoor screen technology,a scheme of pixels, outdoor multiplexing technique (also called pixel sharing technology, virtual pixels to indoor display technology) transplantation.Advantage: color consistency than bitmap module of good way.Weakness: the effect not beautiful, color mixing, horizontal Angle and have off color. Process is relatively complex, anti-static high. Actual pixel resolution do 10,000 more difficult.Features• Compatible with MCS-51® Products• 8K Bytes of In-System Programmable (ISP) Flash Memory• 1000 Write/Erase Cycles• Fully Static Operation: 0 Hz to 33 MHz• Three-level Program Memory Lock• 256 x 8-bit Internal RAM• 32 Programmable I/O Lines• Three 16-bit Timer/Counters• Eigh t Interrupt Sources• Full Duplex UART Serial Channel• Low-power Idle and Power-down Modes• Interrupt Recovery from Power-down Mode• Watchdog Timer• Dual Data Pointer• Power-off FlagDescriptionThe AT89C52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pinout. The on-chip Flash allows the programmemory to be reprogrammed in-system or by a conventional nonvolatile memory programmer.By combining a versatile 8-bit CPU with in system programmable Flash on a monolithicchip, the Atmel AT89C52 is a powerful icrocontroller which provides a highly-flexible and cost-effective solution to many embedded control applications.The AT89C52 provides the following tandard features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator,and clock circuitry. In addition, the AT89C52 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes.The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset.In the Counter function, the register is incremented in response to a 1-to-0 transition at its corresponding external input pin, T2. In this function, the external input is sampled during S5P2 of every machine cycle. When the samples show a high in one cycle and a low in the next cycle, the count is incremented. The new count value appears in the register during S3P1 of the cycle following the one in which the transition was detected. Since two machine cycles (24 oscillator periods) are required to recognize a 1-to-0 transition, the maximum count rate is 1/24 of the oscillator frequency. To nsure that a given level is sampled at least once before it changes, the level should be held for at least one full machine cycle.InterruptsThe AT89C52 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all shown in Figure 10. Each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit in Special Function Register IE. IE also contains a global disable bit, EA, whichdisables all interrupts at once. Note that Table 5 shows that bit position IE.6 is unimplemented. In the AT89C52, bit position IE.5 is also unimplemented.User software should not write 1s to these bit positions, since they may be used in future AT89 products. Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON. Neither of these flags is cleared by hardware when the service routine is vectored to. In fact, the service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt, and that bit will have to be cleared in software. The Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the cycle in which the timers overflow. The values are then polled by the circuitry in the next cycle. However, the Timer 2 flag, TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows.Reference data:1. the ATMEL company AT89S52 technical manuals2.Shenzhen Development Co., Ltd. AT89C523.Fudan University Press, single-chip microprocessor theory, application and test ZHANG You-de, etc.基于AT89C52的LED概述LED(Light Emitting Diode),发光二极管,是一种固态的半导体器件,它可以直接把电转化为光。

LED显示屏专业术语中英对照

LED显示屏专业术语中英对照

LED显示屏专业术语SMT车间(SMT workshop)印刷机printer锡膏solder paste单元板PCB(printed circuit board)元器件component电容capacitance电阻resistance集成电路IC(integrated circuit)过炉wilding回流焊reflow welding表贴三合一SMD 3in1表贴三并一SMD 1in1亚表贴plug-lamp real pixel交流电AC(Alternating current)直流电DC(Direct current)箱体(cabinet)像素点pixel点间距pitch模组module网线进口the entrance of the network cable 航空头connector定位柱located beam排气扇radiator fan提手handle箱体锁lock of the cabinet进气孔air inlet箱体尺寸cabinet dimension密封箱体sealed cabinet简易箱体simple cabinet面罩mask网卡lAN card 排针pin底座base plate装箱体assemble cabinets灌胶gluing电源power supply亮度brightness/luminanceLED 显示屏操作系统(LED display control system)播放系统display system远程控制电脑remote control PC主要控制电脑main control PC磁带录音机video tape recorder调制解调器Moderm网卡net card视频卡video card扫描仪scan machine功率放大器power amplifier激光影碟laser disc插件(DIP)切灯角cut lamp leg后焊check soldering电缆线cable wire电源线power wire接线头connector护线套covered connector排线flat cable光纤fiber cable传输transmit信号signalO型护线套O-type covered connectorU型护线套U-type covered connector显示屏相关参数(LED display’s parameter)同步synchronization异步asynchronization实像素real pixel虚拟像素virtual pixel一致性uniformity净重net weight毛重gross weight相关单位(Units)毫米mm millimeter厘米cm centimeter英寸inch英尺feet长*高length by height铝aluminum铁iron钢steel集装箱container防水测试waterproof test防震测试vibrating testLED显示屏安装方式摆臂式swing arm type吊挂式hang type活动式movable type墙挂式wall-mounted type侧挂式side mounting type坐立式sit type支撑式support type图片类文字翻译1 室内全彩屏P7.62三合一: 10平方米/天P7.62Indoor SMD 3in1 Display: 10m2 /day2 室外全彩屏P20: 15平方米/天P20 Outdoor Full Color Display:15m2 /day3 贴片机产能示例The SMT machine example of daily output3 回流焊机Reflow Soldering Machine3 制造中心Manufacturing Center4 制程能力Manufacturing Ability4 高速贴片机High Speed SMT Machine5 波峰焊机Wave-peak Soldering Machine6 防静电车间Antistatic Workshop7 模组装配车间Modules Assembling Workshop9 品质保证Quality Assurance10整屏老化架Whole Screen Aging Structure11 单灯老化试验Aging Test for Single LED Lamp12光强测试仪Light Intensity Tester13 防水测试Waterproof Test14 模组老化Modules Aging15 振动测试仪Vibration Tester16 冷热冲击测试Thermal Shock Tester17 高低温交变湿热试验箱High-Low Temperature& Humidity Test Chest18 盐雾实验仪Salt Spraying Tester 20 包装运输Packing and Transportation21 环保纸箱Eco-friendly Carton22 航空箱Flight Case23 免熏蒸木箱Fumigation-free Wooden Case24 紫外线潮湿测试仪Accelerated Weather Tester25 自动灌胶机Automatic Dispenser Machine26 全自动插件机Automatic Insert Machine27 高温烤箱High-temperature Oven28 锡膏印刷机Paste Printing Press29 贴片机SMT Machine30 全自动编带机Tape-speed Automatic MoldingMachine31 高低温测试仪Temp&Humi ProgrammableChamberPhotometric Colorimetric Electric Tester for LEDHigh Power MicroscopeLED Aging ProcessLED Attenuation TestingLuminance Intensity TesterKT2811 LCR Digital Bridge TesterHigh Voltage TesterEarth Resistance TesterSalt Spraying TesterThermal Shock TestVibration TesterWaterproof TestingComplete Products Aging Testing盐雾试验箱Salt-fog spray test box老化Aging冷热冲击实验箱Cold and hot shock test box可程式恒温恒湿试验箱Programmable constanttemperature and humidity chamber积分球Integrating sphere烙铁Soldering iron功率计Power meter放大镜megaloscope/magnifier显微镜microscopeLCR数字电桥LCR digibridge灌胶机glue-pouring machine焊锡solder锡炉Solder pot/furnace阴极射线管CRT abbr. cathode ray tube防护等级IP = Ingress Protection相对湿度RH = Relative Humidity脉冲宽度调制PWM = Pulse Width ModulationDOOH = Digital Out-of-home高清串联数字分量HD-SDI = High Definition SerialDigital Interface超高清UHD Ultra High Definition磊晶片Epitaxy Wafer晶粒Chip。

LED照明常用英文翻译对照

LED照明常用英文翻译对照

LED照明常用英文翻译对照1backplane背板2Bandgapvoltagereference带隙电压参考3benchtopsupply工作台电源4BlockDiagram方块图5BodePlot波特图6Bootstrap自举7BottomFETBottomFET8bucketcapcitor桶形电容9chassis机架10Combi-senseCombi-sense11constantcurrentsource恒流源12CoreSataration铁芯饱和13crossoverfrequency交叉频率14currentripple纹波电流15CyclebyCycle逐周期16cycleskipping周期跳步17DeadTime死区时间18DIETemperature核心温度19Disable非使能,无效,禁用,关断20dominantpole主极点21Enable使能,有效,启用22ESDRatingESD额定值23EvaluationBoard评估板24Exceedingthespecificationsbelowmayresultinpermanent damagetothedevice,ordevicemalfunction.Operationoutsideofthe parametersspecifiedintheElectricalCharacteristicssectionisnotimplied.超过下面的规格使用可能引起永久的设备损害或设备故障。

建议不要工作在电特性表规定的参数范围以外。

25Faillingedge下降沿26figureofmerit品质因数27floatchargevoltage浮充电压28flybackpowerstage反驰式功率级29forwardvoltagedrop前向压降30free-running自由运行31Freewheeldiode续流二极管32Fullload满负载33gatedrive栅极驱动34gatedrivestage栅极驱动级35gerberplotGerber图36groundplane接地层37Henry电感单位:亨利38HumanBodyModel人体模式39Hysteresis滞回40inrushcurrent涌入电流41Inverting反相42jittery抖动43Junction结点44Kelvinconnection开尔文连接45LeadFrame引脚框架46LeadFree无铅47level-shift电平移动48Lineregulation电源调整率49loadregulation负载调整率50LotNumber批号51LowDropout低压差52Miller密勒53node节点54Non-Inverting非反相55novel新颖的56offstate关断状态57Operatingsupplyvoltage电源工作电压58outdrivestage输出驱动级59OutofPhase异相60PartNumber产品型号61passtransistorpasstransistor62P-channelMOSFETP沟道MOSFET 63Phasemargin相位裕度64PhaseNode开关节点65portableelectronics便携式电子设备66powerdown掉电67PowerGood电源正常68PowerGroud功率地69PowerSaveMode节电模式70Powerup上电71pulldown下拉72pullup上拉73PulsebyPulse逐脉冲(PulsebyPulse)74pushpullconverter推挽转换器75rampdown斜降76rampup斜升77redundantdiode冗余二极管78resistivedivider电阻分压器79ringing振铃80ripplecurrent纹波电流81risingedge上升沿82senseresistor检测电阻83SequencedPowerSupplys序列电源84shoot-through直通,同时导通85strayinductances.杂散电感86sub-circuit子电路87substrate基板88Telecom电信89ThermalInformation热性能信息90thermalslug散热片91Threshold阈值92timingresistor振荡电阻93TopFETTopFET94Trace线路,走线,引线95Transferfunction传递函数96TripPoint跳变点97turnsratio匝数比,=Np/Ns。

LED显示屏中英文手册

LED显示屏中英文手册

LED电子显示屏用户手册LED electron display handbook for consumerLED电子显示屏硬件部分LED electron display hardware partLED电子显示屏保修证书LED electron display warranty certificate警告Warning警告:为了防止任何身体上的伤害,请在连接开关之前,读这个安装操作规则Warning:To protect any body damage ,please install the instruction before you connect the switch.1在打开开关前,检查所有的交流电源是不是连接好。

Before you open the switch .please check if all the alternating current power were connected correct.2在做任何维护工作之前要先关掉包括LED板'电脑终端'系统盒和监控器在内的所有开关.Please close the switch of LED board ,the computer terminal system box and monitor ,before you do any maintenance.3在开关未关闭时,不要触电源。

When you open the switch ,don't touch the power .警告:为了安装设备驱动程序的损失和数据的丢失,请在操作显示板之前读这个安装设置操作规则。

Warning: To avoid the damage of the driver and the data disappear ,please read the operation rule of the installation device before you operate with the led.1在连接任何电缆之前,请先关掉包括LED板、电脑终端、系统盒和监控器在内的所有开关。

LED显示屏中英文手册

LED显示屏中英文手册

L E D显示屏中英文手册公司标准化编码 [QQX96QT-XQQB89Q8-NQQJ6Q8-MQM9N]LED电子显示屏用户手册LED electron display handbook for consumerLED电子显示屏硬件部分LED electron display hardware partLED电子显示屏保修证书LED electron display warranty certificate警告Warning警告:为了防止任何身体上的伤害,请在连接开关之前,读这个安装操作规则Warning:To protect any body damage ,please install the instruction before you connect the switch.1在打开开关前,检查所有的交流电源是不是连接好。

Before you open the switch .please check if all the alternating current power were connected correct.2在做任何维护工作之前要先关掉包括LED板`电脑终端`系统盒和监控器在内的所有开关. Please close the switch of LED board ,the computer terminal system box and monitor ,before you do any maintenance.3在开关未关闭时,不要触电源。

When you open the switch ,don't touch the power .警告:为了安装设备驱动程序的损失和数据的丢失,请在操作显示板之前读这个安装设置操作规则。

Warning: To avoid the damage of the driver and the data disappear ,please read the operation rule of the installation device before you operate withthe led.1在连接任何电缆之前,请先关掉包括LED板`电脑终端`系统盒和监控器在内的所有开关。

LED显示屏外文翻译

LED显示屏外文翻译

附录3 中英文翻译The led manifestation holdThe LED manifestation hold(LED panel):The LED is a light emitting diode, give out light the English abbreviation of diode, brief name LED. It is 1 kind to passThe control semi-conductor give out light diode of manifestation way, it probably of appearance be from a lot of usually is red of the small light constitute, depend light of bright put out to manifestation character list. Using to the manifestation writing, sketch, picture, animation, condition of the market, video frequency and recording image signal's etc. is various manifestation screen of information.The LED manifestation hold to is divided into a diagram text's manifestation to hold with video frequency manifestation hold, is all constitute by LED matrix piece. The diagram text's manifestation hold can with calculator synchronous manifestation Chinese characters, English The text text origin and sketch,The video frequency manifestation hold adoption microcomputer to carry on control, diagram text, picture combine luxuriant, with solid hour, synchronous, clear information dissemination the way sow Putting various information, returning can manifestation two dimensions, 3D animation, record image, television, VCD program and the spot actual condition. The LED manifestation hold a manifestation an appearance color fresh and gorgeous, Stereoscopic the feeling be strong, quiet like oil painting, move like movie, extensive application in finance, tax administration, industry and business, post and tele, athletics, advertisement, factory mineral business enterprise, transportation, Teach system station, wharf, airport, market, hospital, guest house, bank, stock market, building market, sale line, industry business enterprise management and other public place.The LED's manifestation hold can manifestation variety of numeral, writing, sketch picture,Can not only used for an indoor environment but also used for outdoors environment, have to cast shadow an instrument, television wall, LCD manifestation to hold the advantage that can't compare to.The reason that, the LED be extensively valued but get quick development, is with it have of advantage inseparable. These advantages summarize BE,Bright degree Gao, work the electric voltage be low, achievement consume small and small scaled turn, life span long, bear pound at and function stability. The LED development foreground is extremely vast, currently just toward the higher and bright degree, higher bear weather, higherly give out light density and higherly give out light even, the credibility, whole color turn a direction development.the LED manifestation hold a development process 30 year review1970's at the earliest stage of GaP, GaAsP together quality knot red, Huang, green low give out light the LED of efficiency a beginning already application at the indicator, numeral and writing manifestation .From now on the LED start get into a variety application realm and include astronautics, airplane, car, industry application, correspondence, consume type product etc., all over each section of national economy and thousand 10000.To 1996 LED is in the whole world of sale sum already arrive several USD 1,000,000,000.Though the LED has been be subjected to a color and give out light therestriction of efficiency over several years, have a longevity life because of the GaP and the GaAsP LED, Gao credibility, work the electric current be small, can and TTL, CMOS numeral electric circuit and permit many advantage of etc. as a result has been be subjected to the green Mi of user. Recent decade, Gao Liang4 Du4 turn, whole color's turn has been being LED material and spare part craft technique research of front follow a topic. The extremely high and bright degree(UHB) is that give out light strength to attain or more than 100 mcd LED, call hole again virtuous pull(cd) class LED. Gao Liang4 Du4 the A1 GaInP and InGaN LED develop to make progress very quick, now already arrive normal regulations material GaA1 As, GaAsP, GaP impossible attain of function level.1991 Toshiba in Japan company and the United States the HP company develop into the InGaA1 P 620 nm an orange and extremely high and bright degree LED, 1992 the InGaA1 p 590 nm yellow extremely high and bright degree the LED be practical to turn At the same year, Toshiba company develop the InGaA1 P 573 nm Huang green an extremely high and bright degree LED, method to light as strong as 2 cd.1994 Japan day the second company develop into InGaN450 nm blue(green) color extremely high and bright degree LED. Go to this, color manifestation three Ji colors need be red, green, blue and orange, Huang variety the LED of the color all come to a hole virtuous pull give out light of class strength, realization the extremely high and bright degree turn, the whole color turn and make to give out light tube of outdoor whole color manifestation become reality. Our country development LED start in 70's, the industry appear in 80's.There is around more than 100 business enterprise in whole country, 95% factory house all be engaged in behind way pack produce, need tube Xin almost all from the abroad import. Pass the technique of a few "five years plan" reformation, the technique offend pass and usher in abroad forerunner equipments and parts of key technique, make our country LED of produce the technique have already step forward into one step.Two, extremely high and bright degree LED function:The extremely high and bright degree red A1 GaAsLED and GaAsP-GaP LED compare, have to higherly give out light an efficiency, the flow of transparent Chen low(TS) A1 GaAs LED(640 nm) clear efficiency already close 10 lm/w, ratio the red GaAsP-GaP LED big 1000%.Color and GaAsP-GaP that the extremely high and bright degree InGaAlP LED provide LED homology include,academy blue(560 nm), shallow academy blue(570 nm), yellow(585 nm), shallow Huang(590 nm),orange(605 nm) and pink(625 nm deep red.(640 nm)The transparent Chen bottom A1 GaInP LED give out light an efficiency and the other LED structure and white Chi light source of comparison, the InGaAlP LED absorb the flow of Chen bottom(AS) clear efficiency as 101 m/w, the transparent Chen bottom(TS) want to be 10 -s in height than the GaAsP-GaP flow of LED clear efficiency within the scope of the wave-length of 590 -626 nm for the 201 m/w 2000%;In 560 -s 570 wave-length scopes ratio GaAsP-GaP LED Gao Chu's 2 -s 400%.The extremely high and bright degree InGaN LED provided an orchid color light and green light, its wave-length scope orchid color is 450 -480 nm, orchid green is 500 nm, green is 520 nm,It flow the clear efficiency as 3 -151 m/ws. Extremely high and bright degree LEDcurrently flow a clear efficiency have already exceeded to take the incandescent lamp of color filter, can replace the power incandescent lamp within 1 w, and use a LED array can replace the power incandescent lamp within 150 w. For many application, all of incandescent lamps be an adoption color filter to get red, orange, green and orchid color, but use an extremely high and bright degree LED can then get homology of color. The extremely high and bright degree of the material and InGaN material manufacturing of the recent years AlGaInP LED many extremely high and bright degree LED chip combination together, need not color filter also ability get various color. Include red, orange, Huang, green and blue, currently its giving out light an efficiency all have already exceeded an incandescent lamp, is connecting toward the fluorescent lamp near. Give out light a bright degree Gao have already canned satisfy outdoors at the 1000 mcd all-weather, whole color manifestation of demand, use LED color big screen can performance the sky and ocean, realization 3D animation. The new generation red, green and blue and extremely high and bright degree LED come to an unprecedented function.Three, extremely high and bright degree LED application:rmation indicatorCar signal designation,car indicator's exterior in car's being main be a turn signal, tail lamp and brake light,Main is various appearance in the inner part of car of illuminate and manifestation. The extremely high and bright degree LED used for car indicator and the incandescent lamp of tradition to compare to have many advantage, in the car industry have extensive of market .The LED can experience a stronger machine to pound at and vibrate. Average work life span MTBF ratio incandescent lamp bubble Gao Chu Ji3 quantity class, far far Gao Chu's car of work life span, so flow bottom work, typical model of drive electric current an incandescent lamp to only at least have 12 red, yellow, blue green signal beacon.2.great screen manifestationGreat screen manifestation is extremely high and bright degree LED application of another one huge market, include,color and whole color of the monochrome, double of the sketch, writing, numeral manifestation. Tradition of the big screen have a source manifestation general adoption incandescent lamp, fiber optic, cathode ray tube etc.,Have no source manifestation general adoption turn over the method of card .Form 3 listed a few kinds manifestation of function comparison. The LED manifestation once had been be subjected to LED function and the restriction of the color .Now the extremely high and bright degree AlGaInP, TS-AlGaAs, InGaN LED have already can provide brightness of red, Huang, various green and blue color, can complete satisfy realization whole color big screen manifestation of request. LED manifestation hold can assemble into various structure according to the pixel size, figurine vegetable diameter general small at the 5 mm, monochrome manifestation of each pixel use a LED light of T-1(3/4), double color manifestation of each pixel is double the LED light of T-1(3/4) of the color, whole color manifestation demand 3T-1 be red, green, blue light, perhaps assemble much aer LED light of T-1(3/4) of chip be a pixel. The big pixel then pass pair of many T-1(3/4) red, green, the blue LED light combination together constitute e InGaN(480 nm) blue, InGaN's(515nm) being green be three Ji colors of LED manifestation with the ALGaAS(637 nm) red LED light, can provide a lifelike whole color function, and have bigger color scope to include: blue and green and green and red etc., with international television system committee(NTSC) provision of television color the scope be basic to agree with.3.the LCD manifestation(LCD) carry on the back to illuminateHave 10% adoption to have source light as to carry on the back illuminate atleast in the LCD manifestation, the light source can make LCD manifestation hold of dark of environment bottom easy read, whole color LCD manifestation also demand light source. The LCD carry on the back to illuminate the light source need main have,incandescent lamp bubble, field with the result that give out light, cold cathode fluorescence, LED etc., they be listed on form 4 carry on comparison, among them,the LED have a competition ability most in the LCD carry on the back the lighting,the new extremely high and bright degree AlGaInP, AlGaAs, InGaN LED can provide to high-efficiencily give out light with the color of breadth scope.The LED used for LCD to carry on the back to illuminate main have three kinds of way.(1)Most simple is LED light direct install spread to shoot a film in the LCD of behind, can use many pack of LED light, they should have very breadth of light beam Cape with make stalk to light the even be better. Can also adoption don't pack of tube Xin, general use GaP LED, however use AlGaInP, TS-AlGaAs LED can then under the small electric current work, let up achievement consume.(2)Another a way are an edge light the LCD carry on the back illuminate and use a transparent or translucent rectangle plastics a piece conduct and actions lead light body, is direct it install to spread to shoot a film in the LCD of behind, plastics piece of empress surface Tu2 Shang4 white reflection material, LED light shoot from a flank of plastics piece go into, rest the flank make with white reflection material.(3)LED send out of light ducting fiber optic bunch in, fiber optic bunch of spread and shoot film behind constitute a flat of thin slice, can use dissimilarity of method's taking out from the thin slice the light be a carry on the back of LCD illuminate .Adoption LED conduct and actions carry on the back illuminate of the liquid crystal display can used for ambulation telephone, notebook, along with the small scaled liquid crystal display isin the stanza the electricity the type the correspondence the product of extensive usage, will have greater need to the extremely high and bright degree LED.4.the solid shine on a lightWhole color extremely high and bright degree LED of practical turn with commercialize, make to illuminate a technique to face a new of revolution, solid floodlight make into by many extremely high and bright degree red, blue and green three color LEDses not only can send out a wave-length continuous various adjustable color light, and also can send out a bright degree can reach several 10-100 candlelights of white become lighting light source .Recen Japan day second company make use of its InGaN be blue light LED and fluorescence technique, again released white light the solid give out light a spare part product, its color is 6500 K, the efficiency reach each tile 7.5 flow clear .For homology give out light incandescent lamp and LED solid floodlight of bright degree to say, the achievement of the latterconsume a have the former of 10% -be 20% and the life span of the incandescent lamp's being general be not over 2000 hours, but the life span of the LED light be as long as tens of thousands hours. This kind of physical volume is small, the weight be light and directive good, economy energy, life span long, bear various bad condition of solid light source necessarily will to tradition of the light source market result in pound at. Though this kind of is new to illuminate the cost of solid light source still higher, can application like mineral mountain at some special situation, dive, rob insurance, for use by the military equip of illuminate etc From farsighted see, if the LED the further extension of the production scale of the extremely high and bright degree, cost further lower, it at economy energy and longevity life of the advantage is good enough to make up its price higher bad situation .The extremely high and bright degree LED will probably become a kind of new lightning source which have much of a competition ability.LED显示屏LED显示屏:LED就是light emitting diode ,发光二极管的英文缩写,简称LED。

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LED点阵显示屏中英文对照外文翻译文献(文档含英文原文和中文翻译)译文:基于AT89C52单片机的LED显示屏控制系统的设计摘要这篇文章介绍了基于AT89C52单片机的LED点阵显示屏的软件和硬件开发过程。

使用一个简单的外部电路来控制像素是32×192的显示屏。

用动态扫描,显示屏可以显示6个32×32的点阵汉字。

显示屏也可以分为两个小的显示屏,它可以显示24个像素是16×16的汉字。

可以通过修改代码来改变显示的内容和字符的滚动功能,而且可以根据需要调整字符的滚速或者暂停滚动。

中文字符代码存储在外部存储寄存器中,内存的大小由需要显示的汉字个数决定。

这种显示屏具有体积小,硬件和电路结构简单的优点。

关键词发光二极管汉字显示AT89C52单片机1.导言随着LED显示屏不断改善和美化人们的生活环境,LED显示屏已经成为城市明亮化,现代化、信息化的一项重要标志。

在大的购物商场,火车站,码头,地铁,大量的管理窗口等,我们经常可以看到LED灯光。

LED商业已成为一个快速增长的新产业,拥有巨大的市场空间和光明前景。

文章,图片,动画和视频通过LED发光显示,并且内容可以变换。

一些显示设备的模块化结构,通常有显示模块,控制系统和电源系统。

显示模块是由LED管组成的点阵结构,进行发光显示,可以显示文章,图片,视频等。

控制系统可以控制区域里LED的亮灭,电源系统为显示屏提供电压和电流。

用电脑,取出字符字节,传送到微控制器,然后送到LED点阵显示屏上进行显示,很多室内和室外显示屏都是通过这个方法进行显示的。

按显示的内容区分,LED点阵屏的显示可分为图形显示、图片显示和视频显示三个部分。

与图片显示屏比较,不管是单色或者彩色的图形显示屏,都没有灰色色差,所以,图形显示不能反映丰富的色彩。

视频显示屏不但可以显示运动、清楚和全彩的图像,也可以显示电视和计算机信号。

虽然三者之间有一些不同,但显示的原理基本一样。

单片机具有优良的性价比,体型小,可靠性高,控制能力强,它广泛用于智能仪器、机电一体化的实时过程控制、机器人、家用电器、模糊控制和通讯系统等。

这篇文章讲诉了LED显示屏设计相关原理,以及对硬件的设计和软件流程进行了详细的介绍。

最后,我们对整体的设计进行仿真并对结果进行了分析。

2.系统总体结构的设计通过控制系统实现的目标、功能、可靠性、成本,精度和速度,选择单片机的型号。

根据问题的实况,选择单片机型号主要考虑以下两个方面:首先,单片机要有很强的抗干扰能力,二是单片机要有低成本高效益的特性。

MCS-51单片机在中国有很广的使用,有很多关于它的信息资料,而且可以兼容很多的芯片,尤其是ATMEL公司在2003年研发出的新一代微控制器,89S系列以及低成本高性能的AT89C52。

AT89C52单片机是低电压,高性能CMOS 8位微控制器,这种芯片有8 KB的只读程序存储器(PEROM),它可以反复抹擦,运用了高密度不容易失性内存技术,256字节的随机存取数据存储(RAM),能与MCS-51指令集和8052产品相兼容。

芯片的内置运用了8位中央处理器(CPU)的闪存存储单元,可以在更复杂的控制中使用。

总体的系统电路结构是由AT89C52芯片,时钟电路,复位电路,列、行扫描驱动电路和6个32× 32 LED点阵屏组成。

LED显示屏的整体设计结构如图1所示。

单个显示单元由点阵模块和两个74HC154组成。

行的数据信号分为两部分,是由两个8255A所决定的。

而8255A中数据来自AT89C52的P0口。

两个74HC154芯片输入字符的列扫描信号,12个74HC154共分为六组。

AT89C52的P1.0〜P1.3口提供74HC154输入信号。

外部数据存储器6264和AT89C52 的P0口相连。

图1 LED字符显示的整体结构3.单片机控制系统电路设计汉字的大小是32×32,然而单片机只有32个I/ O口,它不能满足这种设计的需要,所以I / O端口必须要扩展,数据口的扩展要用两个8255A。

数据端口扩展如图2所示,74HC373是锁存八位低地址的锁存器,它为6264的低8位地址提供信号。

6224高八位地址则由端口P2.0〜P2.4所提供。

A0和A1决定8255A内部端口地址。

74HC139是2-4的译码器,它的输入信号是单片机的P2.6和P2.7口,为外部端口设备提供选通信号。

系统中有很多个外部设备,要保证它们的选通,并使它们的地址是唯一、不重复的。

图2 单片机控制系统电路AT89C52单片机的时钟电路是由单片机18,19号引脚(XTALI和XTAL2),12MHz的晶体振荡器,电容C1、C2所组成。

它运用了内部时钟模式。

复位电路与AT89C52的复位输入引脚端相连,它主要由电阻R1,电容C3构成,用了简单的上电复位电路。

4.显示器存储器单元电路的设计在设计中汉字大小是32×32,每个汉字的字符由四个部分(a),(b),(c)和(d)组成,每部分又有四个8×8点阵。

图3是显示模块的电路分解。

(a)〜(b)的行信号由两个8255A输入的,1PA0〜1PA7和1PB0〜1PB7分别为8255A- 1的PA和PB口,2PA0〜2PA7和2PB0〜2PB7分别为8255A- 2的PA和PB口,右边的数字代表由74HC154提供的列扫描信号。

74HC154输入16列选通信号,因为(a)〜(d)要八个信号,因此(a)和(b)用同一个74HC154,(c)和(d)用同一个74HC154。

两个74HC154提供的列扫描信号可以显示一个字符。

在电路工作时,(a)〜(d)扫描相应选通信号,一次只有一个处在选通状态,而别的列处于关闭状态。

显示的数据是由两片8255A同时提供,由于人眼有暂留效应,眼睛只会看到一个稳定字符。

另外,显示每个中文字符要128个字节的空间,然而AT89C52单片机芯片内只有256字节数据存储器,远达不到设计所要求的,所以扩展了6264这个8×8K外部数据存储器。

图3 显示单元电路分解图5.数据单元电路的设计Intel 8255A是一种可编程通用并行输入/输出接口芯片。

可以通过软件设置功能,有很强的通用性。

它可通过CPU数据总线直接连接外部设备,使用很灵活方便。

Intel 8255A接口芯片有三个8位的并行输入和输出端,运用编程方法可以设置这三个端口作为输入端或者输出端。

芯片有基本输入和输出的工作方式,即选通输入/输出和双向输入/输出。

数据在CPU数据总线传输时,它可进行选择性无条件移动,查询或者中断传输。

Intel 8255A芯片的第三端口,就是端口C可以用作数据端,也可以作为控制端。

当端口C作为一个数据端口时,它可用作8位数据端口,但也分别作为两个4位数据端口,每位都可以进行操作,可以设置一个特定的位进行输入或输出,这样对位的控制提供了方便。

在显示单元电路的设计中,两个8255A提供行数据信号,如图4所示。

设计运用了动态扫描的方式,通过控制行或者列扫描来显示汉字。

系统用列扫描方式控制屏的显示,如图5所示为列扫描电路。

12片74HC154组成列扫描电路。

由2片74HC154控制一个字符并显示一个字符32列。

74HC154的输入信号传入显示屏的AT89C52的P1.0的〜P1.3口,第二片的输入信号是P1.7〜P1.4口,12片74HC154根据这种指令工作。

图4 行数据单元电路6.串行通信接口电路的设计PC机和单片机通过串行通讯接口链接。

这个系统为了实现PC 机与单片机的串行通讯功能,把单片机串行接口的电平转换成RS–232C电平标准[11],其中PC机的RS232 口输出电压为±12V。

照顾到单片机与PC 机的通信长度短,而且单片机只能接收命令和数据,所以选择最简单接法:PC机与单片机直接相连,PC机TXD端发出的信号传送到通信电路中再转化为电流信号,当有信号送进来时就有电流流过光耦合器中的红外发光二极管,二极管发出光信号投射到光敏三极管,再转换成电信号输到单片机的RXD 端,实现了以光为媒介的电到光到电信号转换传输过程,而且在电气上是完全阻隔的,减除了输出端对输入端可能产生的干扰和反馈。

它的原理如图6所示。

图6 串行通行接口电路7.软件的设计整体软件设计可分为两大功能块:显示功能和通信功能。

显示部分运用了动态扫描的方式,显示屏可以显示的汉字、字符等数据信息进行传输控制以及显示等功能。

与PC 机的实时通信部分主要用了单片机串口中断接收数据信息,实现了与计算机的实时数据信息传输。

通信部分的主机软件运用了Visual Basic 编程,使用VB 在标准串口通信方面提供的具有强大功能的通信控件MSCOMM,该控件可设置串行通信的数据发送和接收,对串口状态及串口通信的信息格式和协议进行设置,直接用PC机的RS-232/RS-485 串口发送数据。

为了实现单片机与PC 机的可靠通信,必须要双方具有相同的数据格式和波特率,这个设计采用RS-232 通信,一帧10 位的数据格式,9600bit/s 的波特率。

外文原件:Design of LED Display Control System BasedOn AT89C52 Single Chip Microcomputer Abstract—This paper introduces display design process about hardware and software based on AT89C52 single chip microcomputer. We use a simple external circuit to control the display screen, which size is 32 × 192. The display screen also can display the size of the six 32 × 32 dot matrix Chinese characters by a dynamic scan mode, and can be divided into two small display screen, which can display twenty-four Chinese characters whose size is 16×16. We can modify the code to change the content of the display, subtitles can achieve scrolling function and the scroll speed can be adjusted according to requirements, subtitles can also achieve pause function. The Chinese character code stored in external data memory, the capacity of data memory is expanded according to the requirements of Chinese characters we want to show. This display screen has advantages of small volume, few hardware and simple circuit structure.Index Terms—LED, Chinese Character Display, AT89C52I. INTRODUCTIONLED display has become an important symbol of the city lighting, modernization and information society with continuous improvement and beautification of people's living environment [6]. LED lights can be seen in the large shopping malls, railway station, docks, underground station, a variety of management window and so on. LED business has become a fast-growing new industry, a huge market space and bright prospects [9]. The text, pictures, animation a nd video are displayed by LED’s light, and content can be changed. Some components are the display devices of the modular structure, and which usually consists of a display module, control system and power system. The display module is constituted by the lattice structure which consists of LED, and is responsible for light-emitting display; the screen can display text, pictures, video and so on by control system which can control light or dark of LED in the corresponding region; Power system is responsible for transforming input voltage an d current into voltage and current which the screen needs. LED dot matrix display extracted display character font through PC, and sent to the microcontroller, then displayed in the dot matrix screen, which mainly used for display of indoor and outdoor characters. LED dot matrix display can be divided into graphic display, image display and video display by displayed content. Compared with the image display, the characteristics of graphic display is no difference in gray color whether it is monochrome or color display. Therefore, graphic display also fails to reflect the richness of color, and video display can not only show exercise, clear and full-color images, but also show television and computer signals. Although there are somedifferences between the three, but the most basic principles are similar [6].SCM has excellent cost performance, small size, high reliability, strong control, and widely used in smart instruments, mechanical and electrical integration, real-time process control, robotics, domestic appliances, fuzzy control, communications systems and so on.This article described the design by the LED display relevant principle, and the design of hardware and software structure are described in detail, finally, we simulate for the overall design and analyze the results.II. System Overall Structure DesignSingle Chip Microcomputer (SCM) models were selected according to the target, function, reliability, cost, accuracy and speed of the control system. According to the actual situation of the subject, the choice of SCM models mainly considered from the following two aspects: First, SCM has strong anti-interference ability; Second,SCM has a higher cost-effective. Due to MCS-51 is widely used in China, has more information and can compatible with the more peripheral chips too, in particular, ATMEL Corporation, introduced a new generation microcontroller in 2003, that is 89S series, and its typical products with high performance and low cost microcontroller is AT89C52. AT89C52 is a low voltage, high-performance CMOS 8-bit microcontroller, the chip includes 8 KB read-only program memory (PEROM) which erase can be repeated, 256byte random access data memory (RAM), devices adopt high-density nonvolatile memory technology to produce, compatible with the standard MCS-51 instruction set and the 8052 products, while the chip built-in general-purpose 8-bit central processing (CPU) , Flash storage unit, can be applied to the more complex control applications[10].The system was realized by the circuitry which is made up of AT89C52 chip, Clock circuit, reset circuit, column scan driver circuit, line drive circuit and the six32 × 32 LED dot matrix, the overall structure of LED characters display is shown in Fig.1. A display unit is composed of dot matrix and two 74HC154. Line data signal is divided into two parts, which is given by the two 8255A respectively, but the 8255A data are from the P0 port the master controller AT89C52. The column scanning signal of each character was given by the two 74HC154, the 74HC154 12 pieces and was divided into six groups. The input signal of 74HC154 was given by the P1.0~P1.3 of AT89C52. External data memory 6264 connected with the AT89C52 the P0 port.III. SYSTEM HARDWARE CIRCUIT DESIGNA.Circuit Design of MCU Control SystemThe size of Chinese characters is 32 × 32, but microcontroller has 32 I/O port, and can’t meet design requirements, so the I/O port must expand, the data port expansion was implemented by two 8255A. The data port expansion is shown in Fig.2, 74HC373 is the address latch, and latch low eight address, the low eight address signals of 6264 provided by it, but the high eight address signals of 6264 provided by P2.0~P2.4, Internal port of 8255A was chosen by A0 and A1. 74HC139 is 2-4 decoder, whose input signals are provided by P2.6 and P2.7 of SCM, and provided strobe forthe external I / O devices, because the system has more than one external device, make sure that they can not be gated, so that their addresses is the only and do not repeat.The clock circuit of AT89C52 composed of 18, 19 feet from the clock side (XTALI and XTAL2), and 12MHz crystal X, capacitor C1 and C2, and uses on-chip oscillator mode.Reset circuit uses a simple power-on reset circuit, and mainly constitute of resistor R1, capacitor C3, connected to the AT89C52's reset input pin.B.The Circuit Design of Display Memory UnitThe size of Chinese characters is 32×32 in the design, each character composed of four parts which are (a), (b), (c), and (d), and each part composed of four LED matrix which the size is 8 × 8, circuit decomposition map of display unit is shown in Fig.3. The line signals of (a) ~ (b) are given by two 8255A, 1PA0 ~1PA7 and 1PB0 ~1PB7 are PA and PB port of 8255A-1, 2PA0 ~ 2PA7 and 2PB0 ~ 2PB7 are PA and PB port of 8255A-2, the right figures represent column scan signals which is given by 74HC154. 16 column strobes are provided by 74HC154, (a) ~ (d) requires eight signal, respectively, so (a) and (b) share a 74HC154, (c) and (d) shared a 74HC154. Display a character need two 74HC154 which provide column scan signals. When the circuit works, the (a) ~ (d) is gated by scanning signal in proper order, only one was gated at a time, and other columns are extinguished, the displayed data is given by two pieces of 8255A simultaneously, the human eye will see a stable character because of the human eye's persistence of vision. In addition, because the Chinese character for each display needs 128 bytes storage space, but AT89C52 microcontroller chip is only 256 bytes data memory, it is far less than the design requirements, so we the expanded storage space by 8K × 8 external data memory 6264.C.The Design of Ranks Data Unit CircuitInte1 8255A is a universal programmable parallel input/output interface chip. Its function can be set through the software program, and has a strong versatility. It can be directly through the CPU data bus connected to external devices, easy to use and flexible. Inte18255A interface chip has three 8-bit parallel input and output ports, programming methods can be used to set three ports as input ports or output ports. Chips work have the basic input and output, strobe input/output and bidirectional input / output. When the data were transmitted by data bus of CPU, its can choose to unconditionally transfer, query transmission or interrupt transmission. During Inte1 8255A chip three-port, the port C can be used as not only the data port, but also the control port. When the port C is taken as a data port, it can be used as not only 8-bit data port, but also separately as two 4-bit data port, and each bit of the port C can be operated, can set a particular bit to input or output, so provide convenient conditions for bits control.In design of the display unit circuit, the lines data are given by two 8255A, as is shown in Figure 4. This design uses dynamic display means to display Chinese characters, which can be controlled the by the means of line or column scanning, Thesystem uses the method of column scanning to control screen, Specific column scanning circuit is shown in Figure 5. Column scanning circuit composed of 12 pieces of 74HC154.Two pieces of 74HC154 provided 32 strobes to display a character. The input signal of 74HC154 is P1.0 ~ P1.3 which is provided by AT89C52 to control screen, but 12 pieces of 74HC154 were used in the design, they work according to the order, the input of another piece of 74HC154 is P1.4 ~ P1.7 which is provided by AT89C52 to control screen.D.Serial Communication Interface CircuitPC and SCM are linked via a serial communication interface. In order to implement serial communication function between MCU and PC, and serial interface level of SCM will be changed into standard RS-232C level [11]. Where the output voltage of PC’s RS-232C port is ±12V. MCU and PC, taking into account the short distance communication, and microcontroller is mainly responsible for receiving commands and data, so the PC is directly connected with the microcontroller, this is the simplest connection method. the signals which is from PC’s T XD-side were changed into a current signal through the communication circuit, the infrared light-emitting diodes of optocouper have current when a signal occurs, the light signals which is emitted by diode projected onto the phototransistor, and converted to electric signal, then input to the microcontroller RXD side, so photoelectric conversion is implemented, and electrical is completely isolated to avoid the feedback and interference which is produced by output side. as is shown in Figure 6 IV. SOFTWARE DESIGNThe entire software design mainly composes of display program and communication program. The Chinese characters to be displayed on the screen, character and other data for transmission control and display functions were achieved by dynamic scan. Real-time communication parts which communicate with PC receive data information by SCM serial disruption, so real-time data information transmission with PC was implemented.The host computer software was implemented by Visual Basic. In the standard serial communication, MSCOMM which is the power communication control is provided by VB, it can set the serial communication of data sent and received, and the serial communication port status, message formats and protocols are set, directly send data by PC’s RS -232/RS-485 serial port. In order to realized to PC reliable communication with SCM, and ensure that both sides have the same data format and baud rate [11], this design uses RS-232 communications, a 10 bits data format, 9600bit / s baud rate.。

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