液晶显示器驱动方式复习过程.ppt

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1、液晶显示器驱动方式液晶分子的排列CrystallineLiquid CrystallineLiquid K SmC SmA N LBiaxialUnaxialIsotropicTemperature液晶的分類液晶的電光特性異向性(Anisotropic)排列因數()折射率()黏滯係數()介電係數()電導係數 磁化率彈性係數()液晶的光學特性Optical PositiveOptical NegativeHelical AxisOptical AxisOptical Axis液晶驅動原理電極電極液晶Field OFFField ON液晶顯示器主要優缺點優點低電壓驅動。低消耗電流。體積薄，重量輕。

2、可實現大面積化。彩色化容易。缺點視角限制。外加被光源或投射光源。溫度操作範圍限制。液晶顯示器的種類 液晶顯示器扭轉型(Twinst Nematic,TN)1971超扭轉型(Super Twinst Nematic,STN)1984 雙層雙扭轉型(Double Layer STN,DSTN)1987 光相位補償超扭轉型(Film STN,FSTN)1988 主動驅動超扭轉型(AASTN or MLS STN)1992強介電型(Ferroelectric Liquid Crystal:FLC)1980PDLC(Polymer Dispersive LC)1988 PSCT(Polymer Stab

3、ilized Cholesteric Texture)1993Other DS(Dynamic Scattering)1968 PC(Phase Change)1968 GH(Guest Host)1968 ECB(Elcetrical Control Birefregency)1971BTN(Bistable Twist Nematic)1995IPS(In Plane Switch)1995VA(Vertical Alignment)1996TN 型 LCDs 顯示原理Twist 90液晶分子Field OFFField ON利用液晶的旋光特性調變穿透光線液晶的旋光特性消失STN LCDs

4、 顯示原理Twist 270液晶分子Field OFFField ON利用液晶的雙折射特性調變穿透光線TN&STN 電光轉移曲線V-T Curve100%90%10%VnsSTN VsSTNVsTNVnsTNTVTN 與 STN 的電壓漂移T100%VTN ModeT100%VSTN ModeLCDs 驅動方式直接驅動法(Direction Addressing)靜態驅動法(Static Addressing)多工驅動法(Multiplex Addressing)主動驅動法(Active Addressing/Multi-Line Selection)主動矩陣驅動法(Active Matrix

5、 Addressing)兩端元件(MIM,Diode.)三端元件(A-Si:H TFT,Ploy-Si TFT.)Plasma Addressing(PALC)熱掃描驅動法(雷射掃描)光掃描驅動法(電子速掃描LCDs 靜態驅動法LC CellXORVsVcVsigVcVsigVcVsVc-VsONOFF多工驅動法(振幅選擇驅動法,APT)1 2 3 4N 1 2 3Frame 1Frame 2F0DT水平掃描訊號+D-D0垂直影像訊號Row 1Row 2Row 3Row NColumn 1ONOFFONOFFF+DF-DF+DF-D+D-D0+D-D0+D-D0+D-D01 2 3 4NFra

6、me 1液晶畫素電壓T多工驅動法的限制1.01.11.21.3100200APT 驅動波形IAPT 驅動波形APT AddressingIAPT AddressingAPT 與 IAPT 方式比較APT AddressingLow Voltage Segment Driver:2DHigh Voltage Common Driver:2FIAPT AddressingOffset+D for Positive PolarityOffset+F for Negative PolarityVoltage Range of Segment Driver:F+DVoltage Range of Com

7、mon Driver:F+D高容量多工驅動的對策(a)(b)(c)(d)(e)STN LCDs 規格Operation Voltage Vop:Bias Ratio:Steepness:Selection Ratio:STN LCDs 驅動電壓計算If Voff=2V,N=240 rows,Then:APT:Segment Driver:2.96V,Common Driver:44.40VIAPT:Segment&Common Drivers:23.68VSTN LCDs Drivers 架構.移位暫存器(Shifter Register)DCLK串列輸入訊號.閂鎖暫存器(Latch Regi

8、ster)LPF+D 0F-D 2D偏壓位準.DF(HLHL.H).HLHH並列輸出垂直訊號電極2D 02D2DIAPT 參考電壓IAPT 驅動 IC灰階顯示 FRCFrame Rate Control,FRC:灰階顯示 PWMPulse Width Modulation,PWM:灰階顯示 PHMPulse High Modulation,PHM:液晶的頻率響應Vertical Crosstalk of STN LCDsVertical Crosstalk 的抑制(一)每兩條水平線變換一次驅動電壓極性Vertical Crosstalk 的抑制(二)採用補償驅動週期Vertical Cross

9、talk 的抑制(三)一條水平掃描線的掃描週期分割成兩部份，一半的掃描時間是採用正極性的驅動訊號，另一半的時間是採用負極性的驅動訊號。Horizontal Crosstalk of STN LCDs垂直驅動訊號L Line水平掃描波形液晶畫素波形(a)(b)(c)(d)ABABLHorizontal Crosstalk 的抑制垂直驅動訊號L Line水平掃描波形液晶畫素波形(a)(b)(c)(d)傳統驅動方式水平掃描補償波形補償之液晶畫素波形(e)(f)GVLABFrame Response of STN LCDsActive Addressing for STN LCDsActive Add

10、ressing 驅動電壓If Voff=2V,N=240 rows,Then:F =0.730 X 2V=1.460V|G|=0.954 X 2V=21.909VOutput Range of Segment Driver is about 44V.Common Driver of Common Driver is about 3V.Segment Voltage of Active AddressingActive Addressing 的矩陣運算列向量（Column）時間（Time）行向量（Row）Bit-Map Image MatrixRow Function Matrix時間（Time

11、）列（Column）Column Voltage Matrix矩陣運算方式行（Row）行向量（Row）列向量（Column）Bit-Map Image MatrixRow Vector時間（Time）列（Column）Time=Dtk行向量（Row）列向量（Column）第j列Row Function Matrix時間（Time）列（Column）Column Vector垂直序列運算Column Sequential時間序列運算Time SequentialColumn Sequential 硬體架構 NM圖框記憶體 NM圖框記憶體影像資訊 輸入IjNXOR陣列N加法邏輯陣列NM STN L

12、CDs液晶層間隙4.5um液晶材料：低黏滯係數水平驅動函數唯讀記憶體Row Function ROMNSTN LCDs垂直驅動晶片TFT LCDs 垂直驅動晶片1轉2多工器2轉1解多工器Time Sequential 硬體架構 NM圖框記憶體 NM圖框記憶體影像資訊 輸入IjNXOR陣列N加法邏輯陣列水平驅動函數唯讀記憶體Row Function ROMN1轉2多工器2轉1解多工器NM圖框緩衝記憶體NM圖框緩衝記憶體NM STN LCDs液晶層間隙4.5um液晶材料：低黏滯係數STN LCDs垂直驅動晶片TFT LCDs 垂直驅動晶片N主動矩陣式液晶顯示器AM-LCDsTFT LCDs 等效電

13、路Row DriversColumn DriverArrangement of Color Filter R G B R G BR G B R G BR G B R G BRBG RGBRBGRBG RGBRBGRBG RGBRBGRGGBRGGBRGGBRGGBRGW BRGW BRGW BRGW BStripe Triangle Pixel Structure of TFT LCDsCs on Common 與 Cs on Gate 架構液晶畫素TFTGate LineData LineCsCs液晶畫素TFTCommonCommonGate LineData LineCsCs Cs on

14、CommonCs on GateTiming Chart of TFT LCDsFrame TimeGate123NTimeTFT LCDs Driving MethodColumn InversionDot InversionRow InversionFrame InversionDirect Driving of TFT LCDs DC Bias of CommonGrayScale Voltage V0V1V2V3V4V5V6V7V7V6V5V4V3V2V1V01 Frame/1 LineAC Modulation Addressing of TFT LCDsV0V1V2V3V4V5V6

15、V7V7V6V5V4V3V2V1V0Common WaveformGraylevel Voltage1Frame/1 LineTFT LCDs 的電光效應Direct AddressingTFT LCDs 的電光效應AC AddressingTFT LCDs Driving Waveform Cs on Common(一)TFT LCD 驅動波形(Cs on Common,Common=DC Bias)TFT LCDs Driving Waveform Cs on Common(二)TFT LCDs Driving Waveform Cs on Gate TFT 電容效應的影響PixelCgd

16、CgsCsdCsdbCsdb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：二階驅動方式的效應CsClcCgdCsdCgsVctCh(N-1)Ch(N)Vs垂直影像訊號水平掃描訊號Vg水平掃描訊號VgVshVslVstVthVth正極性驅動負極性驅動負極性驅動正極性驅動資料驅動晶片輸出訊號電位液晶畫素電位Vct=Vst-VpVpBlack(+)White(+)White

17、(+)Black(+)Black(-)Black(-)White(-)White(-)TFT 補償驅動法Ch(N-1)Ch(N)Vst=Vct影像訊號波形 Vs水平脈波掃描波形VgeVgeVghlCh(N-1)Ch(N)Vst影像訊號波形VsVge(+)Vge(-)VghlVghl3 Level Addressing4 Level Addressing3 Level AddressingB(+)W(-)B(-)W(+)正極性負極性Vst=VctB(+)B(-)W(+)W(-)B(+)W(-)B(-)W(+)Vp=CgdVghl/Ct正極性負極性正極性Ct=Cs+Clc+Cgd負極性CsVge/

18、CtCsVge/Ct4 Level AddressingVst=VctB(+)B(-)B(-)B(+)W(+)W(+)W(-)W(-)B(+)W(-)B(-)W(+)Vp(+)Vp(-)Vp=CgdVghl/CtCsVge(-)/CtCsVge(+)/Ct正極性負極性正極性負極性Ct=Cs+Clc+CgdCs on Gate 電壓補償方式經由 Cs 將前一條水平脈波的補償波形耦合到動作的液晶畫素,補償 Cgd 造成的電壓漂移及改善液晶畫素內的直流電電壓殘餘.經由 TFT 的 Cgd 造成的電壓漂移經由 TFT 的 Cgd 造成的電壓漂移Comparsion of Addressing Meth

19、odHorizontal Line CrosstalkABCscCscCscTFT SubstrateColor Filter SubstrateHorizontal Area CrosstalkABVertical Area CrosstalkUpLowUpLowShading CrosstalkShading Crosstalk 的抑制Gate Pulse 的傳遞延遲Gate(Scan)Line 的等效阻抗為一連串的串聯 RC 網路，因此 Gate Pulse 在傳遞時會造成波形的傳遞延遲失真。RCRCRCRCN液晶畫素邊際電場效應(一)Reverse Tilt畫素電極鄰近電極共通電極VP

20、VLVAVA VL:Disclination DisappearedVP LC Threshold VoltageReverse Tilt 液晶畫素邊際電場效應(二)TFT水平驅動電極垂直驅動電極RubbingDirectionDisclinationLineReverse TiltDomain改善方法1.增加液晶分子的 預傾角(Pretilt Angle)2.增加 Black Mask 的 遮蔽面積驅動 IC Scan DriverBidirectional Shift RegisterLevel Shift CircuitOutput BufferG1 G2 G3.STVRSTVLCPVR

21、/LVDDDVSSDVDDAVSSASTVRSTVLG1G2GxSerial In Serial Out Analog Data DriverSelectData jData j+1MultiplexerPro:Very simple.Fewer external connections.Con:Many analog inputs.Reduced pixel charging time.System Note:Sample clock:(Dot clock)/N,N Phases.Video Phase:NShift RegisterVideo InQiQi+1Variation on Mu

22、ltiplexerPro:Video Input.Con:Fast data line charging needed.Reduced pixel charging time.System Note:Shift Clock:(Dot Clock)/3 for Mono.Video Phase:3 for Mono.Sample and HoldSerial In Parallel OutAnalog Data Driver(一)Shift RegisterQiQi+1Qi+2Qi+3Video InTransferDouble Sample and Hold/Single PhaseSampl

23、e NSample N+1Sample N+2TTTNN+1N+2Out N-1Out NOut N+1Pro:Video Input.Small load on fast sample-and-holds.Full line time to charge pixel.Con:Complex analog circuit.Physical size.System Note:Shift Clock:Dot Clock.Video Phase:Single Phase.Serial In Parallel OutAnalog Data Driver(二)Shift RegisterQiQi+1Vi

24、deo InTransferDouble Sample and Hold/Multi-PhasePor:Reduced operation frequency.System Note:Video In:NVideo Phase:NShift Clock:(Dot Clock)/N.Digital Data Driver(一)Shift RegisterDACDACDACDACDAC Serial Data BusDigital-to-analog ConvertersPor:Digital input.Con:Complex.Requires sufficient precision to c

25、orrect for LC response variation.Shift RegisterCount Count Count Count CountRamp InSampled RampPor:Digital input.Programmable ramp.Con:Complex circuit.High speed digital circuits.Reduced pixel charging time.Digital Data Driver(二)Shift RegisterDecodeDecodeExternal Fixed voltages1-of-n SelectorSimple

26、DACPro:Digital input.Programmable external voltages.Con:Complex circuit.High speed digital circuits.Many pass gates per data line.Digital Data Driver(三)All Digital Circuit Gamma Correction of LCDXY取像元件取像電路顯像電路顯像元件攝像機測受像機測Analog Correction:2 3 Segment Approach.Digital Correction:External fixed voltag

27、e.Gamma Correction Simple CaseXY取像元件取像電路顯像電路顯像元件攝像機測受像機測TransmissionVoltageThe Block Diagram of the TFT LCD ModuleCCFL BacklightTFT-LCDPANELTiming ControllerScan DriverData DriverRGBCLKHsxVsxTFTLCD ModuleThe TFT LCD Module TypeClassified into two kinds by data driverAnalog type TFT-LCD moduleThe ana

28、log data driversThe analog interface to PCOnly NECDigital type TFT-LCD moduleThe digital data driversThe ADC/LVDS/PanelLink interface to PCMainstreamThe Analog InterfaceGraphicsControllerTFT-LCDPANELTiming ControllerScan DriverAnalog Data DriverHsVsAnalogRGBAnalogRGBCLKHsxVsxPreAmpLevelShifterContro

29、llerPLLPCAnalog ModuleTFTLCD ModuleOSDCCFL BacklightThe ADC InterfaceGraphicsControllerTFT-LCDPANELTiming ControllerScan DriverDigital Data DriverHsVsAnalogRGBDigitalRGBCLKHsxVsxADCBufferControllerPLLPCADC ModuleTFTLCD ModuleOSDCCFL BacklightThe LVDS/PanelLink InterfaceGraphicsControllerLVDS/PanelLi

30、nkTxLVDS/PanelLinkRxTFT-LCDPANELTiming ControllerScan DriverCABLEClockHsVsDigitalRGBDigitalRGBClockHsVsPCTFT-LCD ModuleDigital Data DriverCCFL BacklightAnalog/ADC/LVDS/PanelLinkAnalog InterfaceTrue ColorSampling Error Low Edge SharpnessNoise in the Analog Signal TransmissionAnalog/ADC/LVDS/PanelLink

31、ADC InterfaceMainstream in the Desktop LCD Monitor InterfaceSampling Error Low Edge SharpnessNoise in the Analog Signal TransmissionEMI Issue for High Resolution FormatLow Image Quality and High CostAnalog/ADC/LVDS/PanelLinkLVDS InterfaceMainstream in the Notebook PC InterfaceHigh Edge SharpnessRedu

32、cing EMI&Number of Cable LineHigh Image Quality and Low CostShort Transmission Length&Low Noise MarginCompatible IssuePanelLink InterfaceApplication in the Desktop LCD Monitor InterfaceHigh Edge SharpnessReducing EMI&Number of Cable LineHigh Image Quality and Low CostSecond Supply Source IssueAnalog

33、/ADC/LVDS/PanelLinkTFT Module 設計考慮(一)顯示的影像訊號時序規格(Image Format)圖框重複率(Frame Rate)水平掃描線掃描時間TFT 的 ION/IOFF 電流水平掃描脈線的RC時間常數灰階誤差直流漂移TFT Module 設計考慮(二)選擇適合的驅動方式(Cs on Gate or COM)選擇適合的極性轉換方式驅動IC(Scan&Source)的選取TFT LCDs 模組介面技術的選擇大面積高解析度 TFT LCDs 的開口率影響因素大尺寸面積增加水平驅動電極阻值增加水平驅動波形的時間常數增加水平掃描線減少液晶畫素的有效充放電時間增加解析度

34、增加 Cgd/CLC的比值增加 Vgd 增加 Reverse Tilt Domain 與畫素面積的比例增加 Black Matrix 的遮蔽面積降低畫面品質增加水平驅動電極的寬度增加 TFT 的尺寸增加儲存電容 CS 的面積降低開口率Plasma Addressing LCDsCathode-200VAnode0-200Negative ClowPositive ColumnFaraday DarkCathodeAnode-200V VirtualConnectionSamplingCapacitorAnalogSignalIn-Plane-Switch Mode LCDs偏光版解偏版液晶分子

35、作用電極玻璃基板入射光作用電場方向出射光之極化狀態 未加電場OFF 狀態 施加電場ON 狀態出射光Vertical Alignment Mode LCDs未加電場OFF 狀態施加電場ON 狀態入射光偏光板液晶分子玻璃基板出射光之極化狀態解偏板出射光Comparison of Liquid Crystal ModesStrongly dependent on viewing angle低驅動電壓視角窄小Off(White)On(Black)Slightly dependent on viewing angle廣視角液晶反應速度慢Off(Black)On(White)畫面對比低畫面品質差Slightly dependent on viewing angle畫面對比高廣視角Off(Black)On(White)液晶反應速度快彩色畫面顯像佳TNIPSVA此课件下载可自行编辑修改，仅供参考！此课件下载可自行编辑修改，仅供参考！感谢您的支持，我们努力做得更好！谢谢感谢您的支持，我们努力做得更好！谢谢