STN TFT_LCD knowledge training

1、 STN、TFT_LCD工作原理講解LCD技術(shù)支援部 沈文全2005/11/03Technology for Easy Living !Page23、TFTLCD認(rèn)識2、STN-LCD工作原理1、SUNPLUS Driver認(rèn)識STN工作原理STN產(chǎn)品的驅(qū)動波形STN常見應(yīng)用問題CSTN知識灰度顯示原理Technology for Easy Living !Page3SUNPLUS Driver IC： SPLC780A/B/C/D SPLC100A SPLC063A SPLC783ACharacterFAXCordless PhoneGraphicMobile PhonePDA/DC SPL

2、C560C SPLC562C SPLC563A SPLC564A SPLD803B SPLD804ACOBCOGCOBCOGCOGPDA/dic. SPLC782A SPLC093C/D SPLC095A SPLC701B SPLC501C SPLC502A SPLC506B SPLC550A SPLC086A SPLD1080A SPLD1120ATechnology for Easy Living !Page4LCDLCD的基本結(jié)構(gòu)：的基本結(jié)構(gòu)：液晶盒中間會均勻撒布間隙物質(zhì)spacer, 支撐兩片玻璃，使之間間隙均勻。Glass Substrate Liquid Crystal Glass

3、 Substrate Polarizer/Diffusive Reflector Polarizer spacerspacerTechnology for Easy Living !Page5 偏光片的功能：偏光片的功能：Technology for Easy Living !Page6定向?qū)拥淖饔茫憾ㄏ驅(qū)拥淖饔茫嚎墒挂壕Х肿映尸F(xiàn)規(guī)則的排列 達(dá)到扭轉(zhuǎn)的功能；不同型態(tài)之LCD有不同的扭轉(zhuǎn)角。 Technology for Easy Living !Page7LCDLCD的工作原理：的工作原理： 液晶與偏光片的效應(yīng)組合 未加電壓未加電壓 : : 當(dāng)光線通過上層偏光片, 以一特定的方向進(jìn)入LCD后,

4、 藉由液 晶的扭轉(zhuǎn)將光路徑旋轉(zhuǎn)至特定之角度, 而得以穿透下層偏光片的軸向。 施加電壓施加電壓 : : 原有液晶分子排列的狀態(tài)經(jīng)過施加電壓后, 已失去了旋轉(zhuǎn)光 路徑的功能,因此光線無法透過直交的偏光片。Technology for Easy Living !Page8100%90%10%TNTNTechnology for Easy Living !Page9STNSTN驅(qū)動波形（驅(qū)動波形（分為三大類）分為三大類）：1.1.B BTYPETYPE（還有還有A A、C CTYPETYPE兩種兩種）2.Hi2.HiFAS FAS (high frequency amplitude selection

5、)(high frequency amplitude selection)3.MLA 3.MLA （multi-line addressing)multi-line addressing)Technology for Easy Living !Page10 BIAS的波形算法： A type、 B type波形1/a從COM算出： (Vlcd V1)/(Vlcd V5)=1/aA typeB typeTechnology for Easy Living !Page11B BTYPETYPE：comcomsegseg1 framev0v0v1v1v2v2v3v3v4v4v5v5Technolog

6、y for Easy Living !Page12HiHiFAS FAS (high frequency amplitude selection)(high frequency amplitude selection)1 frameVHVHVLVLV0V0V1V1VMVMTechnology for Easy Living !Page13MLA MLA （multi-line addressing)multi-line addressing)Technology for Easy Living !Page14液晶盒等效電路負(fù)載SegcomLCTechnology for Easy Living

7、 !Page15LCD Bias Circuit StructureVLCDV1V2V3V4OPOPOPOPRRRRNRV0OPBias AdjustV1V2V3V4V5VLCDThe Optimum LCD Bias Voltage equation :(V12 - V22 ) + (V52 - V42) = 0VSSTechnology for Easy Living !Page16升壓電容ITO阻值S1S2S1S2所以：當(dāng)回路中阻抗過大時，RC效應(yīng)明顯，升壓的效能下降。 VOUTV0=VLCDTechnology for Easy Living !Page17GNDV DDVSSVDDS

8、PLC093CSPLC093CITO LAYOUT NG ExampleITO LAYOUT NG Example（SPLC093CSPLC093C） : :Technology for Easy Living !Page18 設(shè)VDD=3V，RVDD=RVSS=500ohm；產(chǎn)品全黑畫面耗電流為100uA，在 雪花畫面為150uA,等效圖為：ICVDDVSSRRVDD2此時實際加在IC上的電壓： VDD2=(VDD-VSS)- IDD*2R=3-0.1= 2.9V當(dāng)顯示耗電流大的雪花畫面時： VDD2 = 2.85V (前章節(jié)有介紹雪花畫面耗電流大的問題)故當(dāng)Vout=3*VDD=9.0V(

9、3倍壓)時，以雪花畫面來測Vout=3* VDD2 =7.55V (若VLCD電壓為8.0V，故此時會顯示淡)ITO LAYOUT NG ExampleITO LAYOUT NG Example（SPLC093CSPLC093C）說明說明 : :Technology for Easy Living !Page19CSTNCSTN相關(guān)知識：相關(guān)知識：Glass Substrate (0.40.7 mm)Liquid Crystal (6 mm)Glass Substrate (0.4 0.7mm)ITO 電極PI 配向膜Polarizer/Diffusive Reflector (0.3 mm)

10、ColorFilterPolarizer (0.3 mm)內(nèi)部結(jié)構(gòu): FSTN + Color Filter: FSTN + Color FilterTechnology for Easy Living !Page20Technology for Easy Living !Page21Technology for Easy Living !Page22CSTN就是: 灰度顯示 +color-filter灰度顯示有兩種方式：FRCFRC: Frame Rate Control（具有FRC調(diào)制灰度的 controller+一般的mono pure driver)PWMPWM: Pulse Widt

11、h Modulation(一般的controller具有PWM調(diào)制灰度的pure driver.FRC & PWM can be combinedFRC & PWM can be combined. Technology for Easy Living !Page23 1stFrame 2ndFrame 3rdFrame 4thFramePixel 1Pixel 2Pixel 3Pixel 4Pixel 55/5 ON4/5 gray3/5 gray2/5 gray1/5 OFFResultTimeTechnology for Easy Living !Page241/32/3

12、3/3Vnon_sVselect我們看到的效果Technology for Easy Living !Page25RMS voltageRMS voltageTransmissionVoffbackgrounddark stateVonV1V2gray 1gray 2灰度與V_T的關(guān)系：Technology for Easy Living !Page26Technology for Easy Living !Page27TFT-LCD認(rèn)識：TFT-TFT-薄膜薄膜電晶體電晶體( (Thin Film Thin Film Transistor)Transistor)非晶硅非晶硅a-a-SiSi:

13、 :目前產(chǎn)品的主流，但目前產(chǎn)品的主流，但遷移率低；多晶硅多晶硅p-p-SiSi ：由于a-Si TFT的主要缺點是遷移率低，原因是薄膜中硅粒很小，并且晶粒結(jié)構(gòu)是隨時機(jī)的，如果使a-Si薄膜 中的硅粒在高溫下再結(jié)晶，使用權(quán)晶粒長在到微米量級，允許電子更加自由地流動，稱為多晶硅，遷移率增大100倍。高溫多晶硅（高溫多晶硅（HTPSHTPS）：制程溫度達(dá)1000度。所以必須采用昂貴的石英玻璃，故未能獲得廣泛應(yīng)用。低溫多晶硅（低溫多晶硅（LTPSLTPS）Low Temperature Ploy SiliconLow Temperature Ploy Silicon ：首先是在玻璃基板上形成一層a-S

14、i ，然后采用激光熱處理，將a-Si 轉(zhuǎn)變?yōu)槎嗑Ч鑠-Si。由于太多的優(yōu)點，將是未來的主流！ TFTTFTLCDLCD分類：分類：Technology for Easy Living !Page28Advantages of LTPS TFT-LCD 較高的電子遷移率 可靠度高 消耗功率小 高解析及高開口率 較簡單的模組結(jié)構(gòu)Technology for Easy Living !Page29GDSDSG (Cr或Mo)DSG（a-Si）或（p-Si）n+a-Si:HSiO2Technology for Easy Living !Page30TFT LCDResolutionSource : S

15、ID TutorialPixel ArrangementTechnology for Easy Living !Page31Arrangement of Color FilterChoose Different Color Filter ArrangementStripe Triangle/Delta Pentile RGBW For Text DisplayFor Graphic DisplayBrightness EnhancementTechnology for Easy Living !Page32Array面板說明comITOCLCGate DriverSource DriverTe

16、chnology for Easy Living !Page33Equivalent Circuit of TFT LCDCS on Common CS on GateEquivalent CircuitClcCsClcCsCommonCommon (N-1)thScan Line (N-1)thScan LineNth Scan LineNth Scan LineCs on Common Mode Cs on Gate ModeCgdCgd液晶電容儲存電容掃描電極資料電極共通電極Mth Data LineMth Data Line資料電極掃描電極:Clc:Cs:Common:Cgd寄生電容液

17、晶畫素電容:Clc+CsClcCsCommon1 (N-1)thScan LineNth Scan LineCs on Gate ModeCgdMth Data Line資料電極Common2Technology for Easy Living !Page34液晶畫素TFTGate LineData LineCsCs液晶畫素TFTCommonCommonGate LineData LineCsCs Cs on CommonCs on GateTechnology for Easy Living !Page35TFT LCDs驅(qū)動波形Cs on CommonSourceDrainGateVgpp

18、VsppVgon-minVgoff-minVshVdhVslVdlVgdVghVglVgdCommonVstVst:影像訊號的直流位準(zhǔn)TgTFT LCD 驅(qū)動波形 (Cs on Common, Common = DC Bias)Technology for Easy Living !Page36TFT LCDs 驅(qū)動波形Cs on Gate SourceDrainGateVgppVsppVgon-minVgoff-minVshVdhVslVdlVgdVghVglVgdCommonVstVst:影像訊號的直流位準(zhǔn)VdVdTgVc:Technology for Easy Living !Page3

19、71 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 ColumnsLines

20、+ + + + + + + + + + + + + + + + + + + 1 2 3 4 512345Frame NColumnsLines+ + +1 2 3 4 512345Frame N+1 ColumnsLines+ + + + + + + + + + + + + + + + + + + +Column InversionDot InversionRow InversionFrame InversionTechnology for Easy Living !Page38Direct Driving and AC Modulation AddressingDC VCOMLarge Si

21、ze Panel : 9v15v HV Source Driver DC Bias of CommonGrayScale Voltage V0V1V2V62V63V63V62V2V1V01 Frame / 1 LineV0V1V2V62V63V63V62V2V1V0Common WaveformGraylevel Voltage1Frame / 1 LineAC VCOMSmall Size Panel : 5v LV Source DriverTechnology for Easy Living !Page39Gate DriverGate Driver Architecture: Bidi

22、rectional Shift RegisterLevel Shift CircuitOutput BufferG1 G2 G3 .STVRSTVLCPVR/LVDDDVSSDVDDAVSSASTVRSTVLG1G2GxTechnology for Easy Living !Page40Source Driver & Gamma BufferDACSDDACSDDACSDDataDataDataDACSDDACSDDACSDDataDataDataDACDACDACDataDataDataChoosing Suitable Source Driver Architecture to s

23、ave powerNeed ultra low power source driver OP designNeed to optimize the OP driving periodGamma buffer stability issueTechnology for Easy Living !Page41Gamma & Gamma BufferUse Gamma Buffer to provide Different Gamma CurveV0V1V2VnV3GSN0GSN1GSN2GSN3GSN255GSN254Technology for Easy Living !Page42Charge PumpBasic Idea of PumpTechnology for Easy L