TFT-LCD的驱动原理及利用驱动改善画质

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上海交通大学工程硕士学位论文
ABSTRACT
become the one of the important research in the course of TFT-LCD’s development. Because of the limit of liquid crystal material itself, the display quality of TFT-LCD panel can not be perfect. People are making efforts to improve the structure of panel and the liquid crystal material, at the same time people are also using other means such as improving optical material and driver system to achieve the target of improving display quality. This paper’s target is to research the driving principle of TFT-LCD, and to improve the TFT-LCD’s slow response time and image sticking caused by liquid crystal material itself in order to improve display quality. TFT-LCD can not display without driving system. This paper presents the research of TFT-LCD’s driving principle, and deeply research of TFT-LCD’s each part such as power circuit, gamma circuit, data processing, timing control circuit. TFT-LCD has some dissatisfactory such as long response time, image sticking and so on. By the deeply research of TFT-LCD’s driving principle we can improve the above dissatisfactory by driving circuit’s improvement. If we want to improve response time, we will do our efforts in four aspects. ①Decrease the viscosity coefficient of the liquid crystal;②Reduce the thickness of the liquid crystal cell;③Increase the drive voltage applied to the liquid crystal cell;④Increase the dielectric coefficient of liquid crystal. Because of the characteristic of liquid crystal itself, we could not decrease the viscosity coefficient of liquid crystal, reduce the thickness of cell and increase the dielectric coefficient of liquid crystal material without limit. Under the circumstance improving response time of liquid crystal by increasing drive voltage become simpler relatively. Base on this principle the Over Driving Technology had been invented, and it efficiently improves the response time of TFT-LCD. By the mean of experiment, I will test and verify the effect of the Over Driving Technology. Image sticking happens because of the impurity irons in liquid crystal. The impurity irons come from ①liquid crystal material, ②PI material, ③ seal and spacer, ④electrodes. In the process of manufactory, it can not avoid
关键词：TFT-LCD 的驱动原理，响应速度，过驱动技术，影像残留，阶调 电压调整
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上海交通大学工程硕士学位论文
ABSTRACT
DISSERTATION TEMPLATE FOR MASTER DEGREE OF ENGINEERING IN SHANGHAI JIAO TONG UNIVERSITY
ABSTRACT
Knowledge economic time’s coming means that the people are walking into the information society. Due to The development of digital technology and multi-media technology and the popularization of information system for family use and personal use, people’ demands of information system are more and more urgent, and the requests of characteristic are stricter. FPD technology has rapidly developed since the nineties of the twentieth century, and it becomes more and more mature. Because FPD has a lot of merits such as high articulation, excellent color, low power consumption, portable type and so on, it is widely used in above area. It has a very vast prospect. Among the FPD market, Thin Film Transistor Liquid Crystal Display (TFT-LCD) occupies the important position of the whole FPD market because of its low voltage, low power consumption, big information capacity, easy to colorize, long life time, non-radiation and so on. It is estimated that the TFT-LCD will become the mainstream product and one of the mainstay of the economy product of the global economic. FPD industry in China has developed since twenty years ago, and has been provided with industry scale. With the development of FPD industry, all of the makers can do very well in output and process on the same level, so the last winner factor is the research and design of the product, display quality will be the key factor. TFT-LCD is valued by the people’s eyes because people can distinguish light and shade, resolution ratio, contrast. The key point of TFT-LCD industry recently and from now on is the technology to design and manufacture high colorful and high display quality, it is also very important for TV-use TFT-LCD industry before long. In other words, improving display quality will
上海交通大学 硕士学位论文 TFT-LCD的驱动原理及利用驱动改善画质 姓名：顾筠筠 申请学位级别：硕士 专业：电子与通信工程 指导教师：李荣玉;张徐 20081101
上海交通大学工程硕士学位论文
摘要
TFT-LCD 的驱动原理及利用驱动改善画质
摘 要
知识经济时代的到来代表着人类逐步进入信息化社会。数字技术、 多媒体技术的迅速发展以及家庭与个人电子信息系统逐步的推广，人们 对信息显示的需求越来越迫切、广泛，其要求也越来越高。其中，平板 显示（FPD）技术自 20 世纪 90 年代开始迅速发展并逐步走向成熟。由于 平板显示其具有清晰度高、图像色彩好、省电、轻薄、便于携带等优点， 已被广泛应用于上述信息显示产品中，具有广阔的市场前景。在 FPD 市 场中，薄膜晶体管液晶显示器（TFT-LCD）凭着其低压、低功耗、显示 信息量大、易于彩色化、寿命长、无辐射等优异特性占据整个平板显示 技术的主导地位，据预计，TFT-LCD 产品将是未来平板显示的主流产品 和全球重要的支柱性产业之一。 中国 FPD 产业经过 20 多年的发展已经形 成坚实的基础，具备了一定的产业规模。 随着产业的发展，最终大家在产能和工艺方面都可以做得很好，因 此最后决胜因素在于技术研发，其中显示画质将是关键。TFT-LCD 是人 们凭视觉来评价的产品， 因为人眼对明暗度、 分辨率极其敏锐。 TFT-LCD 产业目前以及今后的重点其实是要具有能设计和制造出色彩及影像品质 更好的技术，这对日后以电视为主要应用市场的 TFT-LCD 产业显得格外 重要。换句话说，提高显示画质将成为液晶显示发展过程中重要的研究 课题之一。因为由于液晶材料本身的限制，面板的显示画质无法做到完 美，所以人们在改善面板结构和液晶材料的同时，也通过其他的手段，
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上海交通大学工程硕士学位论文
Fra Baidu bibliotek摘要
如通过外部光学材料、驱动系统等方面的改善以到达提高显示画质的目 的。本课题的目标是在对 TFT-LCD 驱动原理深入研究的基础上，对在工 程中出现的由液晶自身缺点导致的响应速度慢、影像残留等问题进行对 策和改善，以达到提高产品画质的目的。 TFT-LCD 一定要有配套的驱动系统才可以显示。本课题将研究 TFT-LCD 的驱动原理，深入研究 TFT-LCD 的工作电源、阶调电压、信 号传输、时钟控制等构成驱动系统的各个模块。由于液晶自身的缺点， 在画质方面存在很多不尽如人意的缺点，如响应速度慢、影像残留等问 题。通过深入研究 TFT-LCD 的驱动原理，并通过利用驱动改善实际工程 中出现的上述问题。 提高响应速度，需要从下面四个方面进行努力：①减小液晶材料的 粘滞系数；②减小液晶单元盒厚度；③增大液晶材料的介电系数；④增 大液晶单元盒驱动电压。由于液晶材料的自身特性限制，响应时间的整 体提升通过增大液晶单元盒驱动电压的方法来实现相对容易。基于该原 理，采用 Over Driving 技术来提高响应速度。通过实验的方法，验证采用 Over Driving 技术的效果。 影像残留产生的原因是液晶中混有杂质离子，来源于：①液晶材料、 ②配向膜材料、③封框胶及垫料、④电极。在制造的过程中，不可避免 的会产生上述离子。通过调整阶调电压来减弱影像残留的严重程度。也 通过实验的方法验证采用该方法的效果。