LED背光技术资料

ContentsLED BLU Marketing demand in GeneralProduct, Technology issues and TrendSummary2LED Demand by application3Just about to start the large size LED BLU4WW LCD Panel Forecast0100,000200,000300,000400,000500,000600,000K p c sTV 54,14179,787105,464123,977140,243155,157 NB 79,772103,807123,106142,926164,152190,760 Monitor 140,119172,258183,968195,330204,372215,311Total274,032355,852412,538462,233508,767561,228200620072008200920102011Source: DisplaySearch Q3/2007WW LCD Panel ForecastSource : Displaybank20085WW LED BLU ApplicationSource: Coretronic/Displaybank20076LED BLU productsSpecial LED BLU application are under development:Monitor: 20.8”& 21.3”for Medical & Advertisement & Printing30”for High-End GraphicTV: 52”for High-Contrast Home Theater application56”for High-Bright PID application7WW LED TV BLU Market Forecast8Source: DisplaySearch, 2006 ----a little bit conservative But catch upSummary the Demand on LED BLUNB had started since 2005, and will be booming in 2008.¾Shooting for Ultra Thin and Power saving¾18% in 2008, (4% in 2007)¾55% in 2011Monitor had some Niche market already¾Shooting for precise and life time stable color point (with static ADC), such as Medical and Advertisement application ¾Also for High-End value-add name brand will start first by 2009¾Only 1% in 2009TV will focus at large size (>52”) premium product¾Shooting for Dynamic ADC for highest contrast and power saving¾5% in 20099ContentsLED BLU Marketing demand in GeneralProduct, Technology issues and TrendSummary10Example of a 24”BLU Optical Spec.Source: Young Lighting Inc. Q1/20081112Development Trend of BLUsNumber of Films are reducedBut LED BLU will follow the trend of CCFLWedge LGP DBEFD BEF Thin Flat V-cut LGP B diffuser LEDsCCFL Reflector13MCPCB Module with M-power 3 in 1 LTCC PKGMCPCB Module With S-power 3-in-1 PLCC PKGMCPCB Modulewith H-power white-LED and RGB LEDMCPCB Module with S/M-power RGB LED and white LEDEdge-liteFR4 Module with S-power RGB single LEDFR4 Modulewith H-power RGB single LEDFR4 Module with S-power RGB 3 in 1 LEDDirect-liteFR4 Module with S-power white LEDLED ModulesSource: Young Lighting Inc. Q1/2008Structure of LED LBUDirect-liteEdge-litePANELFILMSLGPCU CASELEDLIGHTBARSource: Young Lighting Inc. Q1/20081415Edge-Lite Light Bar for Monitor15Reflector foil with back side adhesiveMCPCBH-power White, or S-Power WhiteSource: Young Lighting Inc. Q1/2008The Advantage & Challenge of LED BLUAdvantage¾Hg free¾High color gamut by using RGB LED¾Long Life in RGB design¾Thin form factor design¾Potentially for Color Filter-Less (CFL) panel applicationChallenge¾Cost still high, compare to CCFL in 2008NB ( ~1.7X for 15.4”W)MNT ( ~4.5X for 24”W)TV ( ~5.2X for 52”)¾“Life”will be shorter on Y-White & RG-White LED¾Binning management for color uniformity¾Thermal management and color feedback control for long term color stability16Special concern of a LED BLUFor NB¾Ultra thin & Light weight¾Power saving by using the Yellow phosphor¾Yield rate of V-cut or Double V-cut LGP injectionFor Monitor¾Static Area Dimming Control (ADC) for precise color and uniformity¾RG-White solution for lower cost¾Ultra thin Edge-Lite design for large sizeHigh Thermal density at MCPCBHot spot, or mixing distance issueFor TV¾Dynamic ADC for contrast ratio enhancement and Power Saving¾Large area Color uniformity, du’v’< 0.005¾The complexity, due to thousands of LED17More challenge than CCFL (1)Chip selection¾ , Wave length ÆNTSC color gamut range & RBG color point¾Vf, Forward volt.Ædriver complexity & LED layout arrangement ¾Iv, Brightness Æefficiency and power consumptionBinning¾Influence the usage rate of LED¾Impact the color uniformity very muchPackage type¾The cavity wall angle, surface color & finish Æwider light pattern angle and shorter color mixing distance¾Encapsulation material ÆLight efficiency & angle for color mixing¾Heat slug or lead frame only Æthermal coefficient (Rth)1819The band pass spectrum of a Color Filter (CF) and the LED DominateWavelength (DW) have to be in-line to meet the correct color point and gamutChip selection率(nm)Color filter 帯Light of LED20⎥⎥⎥⎥⎦⎤⎢⎢⎢⎢⎣⎡⎟⎟⎟⎟⎠⎞⎜⎜⎜⎜⎝⎛=n d X )2sin(arcsin tan 2αestimation of mixing area d: distance LED center -LED center: viewing angle LED n: index lightguideColor Mixing AreaSource:OSRAMAction to improve the “d”:1.By using a 2’nd Lens, if we have space2.By special pattern on (or near) the input surface of LGPMore challenge than CCFL (2)Light bar type¾FR4, or MCPCB ÆThermal resistance and cost trade offThermal solution¾Thermal resistance calculation Æestimate the temperature before fabrication¾Thermal pad, black paint, heat pipe selection ÆBack cover temperature uniformityOptical design¾S/W design tool ÆFast design cycleWhich combines the factor of LEDs, # of Films, T-junction, Driving method and Specification ¾LED count and placement ÆColor uniformity (du’v’) and corner brightness¾Small chip or Power chip? Æcolor mixing distance, or BLU thickness¾Light Bar arrangement ÆColor MURALGP or diffuser plate pattern design¾S/W design tools & printing material Æbrightness & uniformity¾Special pattern on or near the light input surface ÆReduce the “HOT SPOT”of LEDs21Rth comparison of MCPCB and FR4FR4 MCPCB picture Vf 5.809 5.734TJ unction( )130.23113.05 TL ead( )60.377.3 TA ( )24.122.8 Rth J-L ( /W)34.3917.81FR4 MCPCBRemarks :1.Rth(J to backcover) will be 130 ~ 150, if for S-Power LED2.MCPCB will be good for Hi-Power LED Hi-Power LEDSource: Young Lighting Inc. Q1/200822More challenge than CCFL (3)Driver design¾Current balance ÆKey to color uniformityTo guarantee the same current to ALL LEDs¾Driver efficiency and PCB layout ÆTo lower and uniform thetemperature¾CMS/ADC ÆColor stability & better contrast2D and/or 3D Local dimming architectureSystem Integration ÆOptimized with System Scalar (Set maker) board and/or T-Con board (Panel maker)Pixel compensation ÆBy changing gray scale of cells, to get better details at dark schemeLife time & Reliability prediction¾Find out formula and Ea (Temperature parameter), N (current/ power parameter) To calculate the LED life time after 1200 hrs HTOL test¾Acceleration Life Test (ALT) ÆTo calculate the life time at certain LED Tj, which reflect to the back cover temperature232424”LED Driver with CMS18LED per string, 30 strings in parallelRGB Color SensorLED Driver Micro controller1 B o o s t C o n v e r t e r (R E D )1 B o o s t C o n v e r t e r (G r e e n )1 B o o s t C o n v e r t e r (B l u e )C N 2C N 2C N 2EEPROMI2C CommandVdd24V InputLED BacklightADC 10 bitVddThermal sensorColor Feed Back Control ICTcon BoardV_syncSystem boardMain BoardSyncI 2CI 2CP W M _RP W M _GP W M _BSource: Young Lighting Inc. Q1/2008LED Driver Board252D ADC Power SavingSource: Samsung SID Show 20073D LED BKL Color Gamut RepresentationSource: SONY SID Show 2007262724”Static ADCAccording to the LED binning,we grouping the same bin into same blockBIN1BIN12BIN4BIN5 BIN11BIN3ABSource: Young Lighting Inc. Q1/200828Number of LED for BLUs, for example3001980, w/ADCS, 3-in-1DL52”TV2096S, 3-in-1 RG-W EL 20.1”MNT 210300H, RGB DL 46”TV 2001560, w/ADC S, 3-in-1DL 46”TV 100120H, RG-W EL 30”MNT 55540S, 3-in-1RGB DL 24”MNT 460S, Y-W EL 15.4”NB LED Power # of LED LED Type BLU TypeSource: Young Lighting Inc. Q1/2008SummaryThe sweet size spot of LED BLU in 2008/9¾NB (12.1”~17”) will go first, than,¾TV (52”~65”), finally,¾MNT (20.1”~24”)LED Efficiency goes up¾RGB, 6 LM >>>> 45 LM/W¾Y-White, 12 LM >>>> 85 LM/W (ref. to CCFLs70%)¾RG-White, 8 LM >>>> 50 LM/W# of LED will continues reduced, for example:¾Target a 46”120 ea H-power RG-W BLU, by the end of 2008LED Cost goes down yearly, IP protected:¾ 1.8~1.5 usd for Hi-Power¾ 1.0~0.75 usd for M-Power¾0.3~0.25 usd for S-PowerRG-White will meet 85% color gamut¾Save 25% cost than RGB29Thank you for your attention30。