1、TFT-LCD基本原理与设计 课程大纲vTFT-LCD 簡介 液晶的光电特性 TFT LCDs A/C 架构 TFT LCDs 模組架构v TFT-LCD 驱动原理 Driving method Driving waveform 电容效应v TFT-LCD 设计主动矩阵式液晶显示器AM-LCDs Monitor SystemLCD TimingControllerLCDPanelData DriverScan DriverRGB Digital DataGMA1GMA181818PowerSupplyCircuitBacklightPowerSupplyBacklightR5:0G5:0B5:
2、0HsVsCLKDE+5VGNDData&Scan Driver Power SupplyData DriversControl SignalsPC InterfacePCRGBHsVsTFT-LCD ModulePCGMA1GMA184A/DInterfaceorDigitalInterfaceScan Control Signals主动矩阵式液晶显示器AM-LCDs Panel Structure主动矩阵式液晶显示器AM-LCDs Panel Structure主动矩阵式液晶显示器AM-LCDs Panel Structure主动矩阵式液晶显示器AM-LCDs Panel Structur
3、eClcTFT SubstrateColor Filter SubstrateRGBClcClcRBG主动矩阵式液晶显示器AM-LCDs Panel Structure图一：沒有加入电压，光线透出 图二：加入电压，光线遮蔽 TN 型 LCDs 显示原理TN Mode LCDs Field ON入射光偏光板液晶分子玻璃基板出射光之极化状态解偏板出射光未加电场OFF 状态TN&STN 电光转移曲线V-T Curve100%90%10%VnsSTN VsSTNVsTNVnsTNVIn-Plane-Switch Mode LCDs偏光板解偏板液晶分子作用电极玻璃基板入射光作用电场方向出射光之极化状态
4、未加电场“OFF”状态 施加电场“ON”状态出射光Vertical Alignment Mode LCDs未加电场OFF 状态施加电场ON 状态入射光偏光板液晶分子玻璃基板出射光之极化狀态解偏板出射光Comparison of LC ModesStrongly dependent on viewing angle低驱动电压視角窄小Off(White)On(Black)Slightly dependent on viewing angle广视角液晶反应速度慢Off(Black)On(White)画面对比低画面品质差Slightly dependent on viewing angle画面对比高广
5、視角Off(Black)On(White)液晶反应速度快彩色画面显像佳TNIPSVA主动矩阵式液晶显示器AM-LCDs Panel StructureTFT-LCD ModuleTTLLVDSPanel LinkSingalControllerDC/DCDirver ICinvertorTFT-LCDBLX-PCDYPCBGammaGen.ComponentEMITFT CharacteristicId1020Vg10E-610E-1110E-12-5-10TFT LCDs 等效电路Row DriversColumn Driver1H1HClcCsCsCsCsCsCsCsCsCsClcClcC
6、lcClcClcClcClcClcTiming Chart of TFT LCDsFrame TimeGate123N1HL1L2L3DATATFT LCDs Driving Method1 2 3 4 512345Frame NColumnsLines+1 2 3 4 512345Frame N+1 ColumnsLines 1 2 3 4 512345Frame NColumnsLines+1 2 3 4 512345Frame N+1 ColumnsLines +1 2 3 4 512345Frame NColumnsLines+1 2 3 4 512345Frame N+1 Colum
7、nsLines +1 2 3 4 512345Frame NColumnsLines+1 2 3 4 512345Frame N+1 ColumnsLines+Column InversionDot InversionRow InversionFrame InversionDirect Driving of TFT LCDs DC Bias of CommonGrayScale Voltage V0V1V2V62V63V63V62V2V1V01 Frame/1 LineAC Modulation Addressing of TFT LCDsV0V1V2V62V63V63V62V2V1V0Com
8、mon WaveformGraylevel Voltage1Frame/1 LineTFT LCDs 的电光效应Direct AddressingT100%VVthVth:液晶的操作臨界電壓共通電極訊號位準正極性訊號時光電轉移曲線負極性訊號時光電轉移曲線Vth負極性時臨界電壓正極性時臨界電壓5V3.5V6.5VTFT LCDs 的电光效应AC AddressingT100%V5V-1.5VVthVth:液晶的操作臨界電壓 正極性訊號時共通電極訊號位準 負極性訊號時共通電極訊號位準正極性訊號時光電轉移曲線負極性訊號時光電轉移曲線VthPixel Structure of TFT LCDsClcC
9、sClcCsCommonCommon (N-1)thScan Line (N-1)thScan LineNth Scan LineNth Scan LineCs on Common Mode Cs on Gate ModeCgdCgd液晶电容儲存电容扫描电极资料电极共通电極Mth Data LineMth Data Line资料电极扫描电极:Clc:Cs:Common:Cgd寄生电容液晶画素电容:Clc+CsCs on Common 与 Cs on Gate 液晶画素TFTGate LineData LineCsCs液晶画素TFTCommonCommonGate LineData LineCs
10、Cs Cs on CommonCs on GateTFT LCDs Driving Waveform Cs on Common(一)SourceDrainGateVgppVsppVgon-minVgoff-minVshVdhVslVdlVgdVghVglVgdCommonVstVst:影像訊號的直流位準TgTFT LCD 驱动波形(Cs on Common,Common=DC Bias)TFT LCDs Driving Waveform Cs on Gate SourceDrainGateVgppVsppVgon-minVgoff-minVshVdhVslVdlVgdVghVglVgdComm
11、onVstVst:影像訊號的直流位準VdVdTgVc:TFT 电容效应的响应PixelCgdCgsCsdCsdbCsdbVVVVVVpFCpFCpFCExCCCVCCCCCVCVgdglghghlgdsLCLCsgdghlgdsdLCsgdghlgdgd43.13005.08.02.005.030102005.0,8.0,2.0:二階驱动方式的效应CsClcCgdCsdCgsVctCh(N-1)Ch(N)Vs垂直影像讯号水平扫描讯号 Vg水平扫描讯号 VgVshVslVstVthVth正极性驱动负极性驱动负极性驱动正极性驱动资料驱动晶片输出讯号电位液晶画素电位Vct=Vst-VpVpBlack
12、(+)White(+)White(+)Black(+)Black(-)Black(-)White(-)White(-)TFT 补偿驱动法Ch(N-1)Ch(N)Vst=Vct影像讯号波形 Vs水平脉波扫描波形VgeVgeVghlsghlgdgeCVCV3 Level AddressingTFT-LCD Module 设计(一)v订定TFT-LCD Module Spec-Resolution/Power/Dimension.vVideo Signal Format/Scan Line Period(Hs)/Frame Period(Vs)vTFT的 ION/IOFF 电流 ION必须于一条水平
13、扫描线时间将影像电压充入液晶电容(Clc)IOFF必须使充入液晶电容中的影像电容维持一个Frame的时间v直流漂移(DC Offset)当Scan Line上Gate Pule关闭时,透过离散电容(Cgd,Cgs,Cds),对画素电极(Pixel Electrode)所造成的Feed through效应.TFT-LCD Module 设计(二)v水平扫描脉线的RC时间常数高解析度时,必须降低RC时间常数,以利液晶电容之充放电.v液晶的电光转移特性曲线(V-T Curve)必须量测LCD Panel正确之V-T Curve,以利Gamma Correctionv选择适合的驱动方式(Cs on Gate or COM)考虑Feed Through效应的补偿及VCOM电压的调整.v驱动IC(Scan&Data)的选取针对LCM的解析度及LCD Panel的元件参数选用Driver IC.vControl PCB的设计 针对所选定的Driver IC,Control PCB提供其所须之控制讯号.33谢谢！谢谢！
