TFT-LCD-驱动原理与系统(1)

1、.1TFT LCD 驅動原理與系統.2TFT LCD 驅動原理與系統 液晶及液晶顯示器簡介 TFT LCD 驅動原理 影響TFT LCD 畫面品質的因素 TFT LCD Driver IC LCD 數位界面簡介 背光板簡介 未來趨勢與走向.3被動式/主動矩陣式液晶顯示器Passive/Active Matrix LCDYelectrodeXelectrodePixel.4The Color Pixel of TFT LCDColor Filter SubstrateTFT SubstrateWhite LightColor LightRGBBGRClcClcClc.5Arrangement o

2、f Color FilterR G B R G BR G B R G BR G B R G BGRBGRBG RBRBG RBGRBGR G R GGBGBR G R GGBGBR G R GW B W BR G R GW B W BStripeTriangleGRBGRBG RBGRBGMosaic.6Aperture Ratioa-SiDrain electrodeGate electrodeInsulatorSource electroden+ a-SiAdjacent gate electrodeInsulator (dielectric substance)Display elect

3、rodesTFT pixelEffective area: 40.7%Capacitor.7TFT LCD 驅動基本驅動波形極性反轉(polarity inversion) - Frame, row, column, dot電容耦合驅動 - 二階,三階,四階.8Timing Chart of TFT LCDSFrame TimeTimeGate123N1H.9TFTL LCDS Driving Method 123451+2+3+4+5+ 1234512345 123451+23+45+ 1234512+34+5 123451+2+3+4+5+ 123451+2+3+4+5+ 123451+2

4、+3+4+5+ 123451+2+3+4+5+FrameNColumnsFrameN+1ColumnsFrameNColumns FrameN+1ColumnsColumnInversionDotInversionFrameNColumnsFrameN+1ColumnsFrameNColumns FrameN+1ColumnsFrameInversionRowInversion.10Direct Driving of TFT LCDsDCBiasofCommon1 Frame / 1 LineGaryScal VoltageV63V62.V1V0V0V1.V62V63.11Vcom Ac Mo

5、dulationAddressing of TFT LCDs1 Frame / 1 LineCommonWaveformGraylevelVoltageV0V0 V1V1V2V2V63V62V62V63.12Direct Driving Vs Vcom Modulation Direct Driving Frame , Row , Column & pixel inversion available Cancel crosstalk & remove flicker ：image quality Improve Power dissipation Vcom Modulation Availab

6、le Frame & Row inversion Poor Power dissipation.13影響 LCD 畫面品質的因素 Horizontal Crosstalk Vertical Crosstalk Shading Crosstalk.14液晶電容的效應 液晶電容CLC會隨液晶作用電壓的改變而變化，因此在驅動液晶時會有殘存的DC成份，其所造成的影響 Image Sticking. Picture Flicker. 液晶作用電壓大時，液晶分子趨向平行電場方向排列 液晶作用電場小時，液晶分子趨向垂直電場方向排列 Vp = Vgd Vgd Cgd VghlCgd + Cs + CCgd V

7、ghlCgd + Cs + C.15Horizontal Line CrosstalkRGBCscCscCscColor Filter SubstrateBASignal of A LineSignal of B LineCommon WaveformDifference of Effective Voltage in B LineBlack LevelGray LevelGray Level.16Horizontal Area CrosstalkBASignal of A LineSignal of B LineCommonWaveform V15m) Data-to-data skew t

8、olerance 1 clock cycle.36TMDSTMDS (Transition Minimized Differential Signaling)is an interface standard based on PanelLink Technology developed by Silicon Image, Inc.SwingControlEncoder/SerializedPLLGraphicControllerTerminationControlRecovery/Decorder/DesirializerPLLLCDPanelDataDataDEDEControlsContr

9、olsClockClockTX1(Green)TX0(Blue)TX2(Red)Clock24524/365VCCVCCParallelData(CMOS)ParallelData(CMOS)TMDSI/FHostMonitorBlock Diagram of TNDS.37DVI DVI (digital visual interface) Promoted by DDWG Intel, IBM, HP, Compaq, NEC, Fujitsu, silicon image Dual channel TMDS Support VGA to QXGA Pixel clock：25mhz 33

10、0mhz.38DVIDVI:Molex 24 + 5 pin connector pin assignmentpinSignal AssignmentpinSignal AssignmentpinSignal Assignment1TMDS Data2-9TMDS Data1-17TMDS Data0-2TMDS Data2+10TMDS Data1+18TMDS Data0+3TMDS Data2/4 Shield11TMDS Data1/3 Shield19TMDS Data0/5 Shield4TMDS Data4-12TMDS Data3-20TMDS Data5-5TMDS Data

11、4+13TMDS Data3+21TMDS Data5+6DDC Clock14+5V power22TMDS Clock Shield7DDC Data15Ground(return for +5V,Hsync,and Vsync)23TMDS Clock+8Analog Vertical Sync16Hot Plug Detect24TMDS Clock-C1Analog RedC2Analog GreenC3Analog BlueC4Analog Horizontal HyncC5Analog Ground (analog R,G,&Breturn)Pin 1Pin 24Pin 8Pin 17C1 C2C4.39GVIF GVIF(gigabit video interface) Promoted by SONY Allows using small connector and long cable(10m) Only one pair differential signal used Support 24bit/pixel, XGA Pixel clock：25mhz 65mhz 400mv voltage swing DC balancing Using 2pair, support to SXGA.