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1、2019/1/30,Write by Wang C.W.,1,液晶顯示器驅動系統 講師 : 陳建斌 楊和興 王清桐 王智偉,課程大綱 液晶物質簡介 液晶的電光效應 液晶基本驅動原理 STN LCDs 驅動原理 TFT LCDs 驅動原理 影響TFT LCDs 畫面品質的因素 Driver IC 簡介 TFT LCDs 模組及介面技術簡介,2019/1/30,Write by Wang C.W.,2,液晶物質的相變化,固體結晶,液晶,液體,加熱,加熱,冷卻,冷卻,2019/1/30,Write by Wang C.W.,3,液晶分子的種類,2019/1/30,Write by Wang C.W.
2、,4,液晶分子的排列,Crystalline,Liquid Crystalline,Liquid,K SmC SmA N L,Biaxial,Unaxial,Isotropic,Temperature,2019/1/30,Write by Wang C.W.,5,液晶的分類,2019/1/30,Write by Wang C.W.,6,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 ( ),2019/1/30,Write by Wang C.W.,7,液晶的光學特性,Optical Posit
3、ive,Optical Negative,Helical Axis Optical Axis,Optical Axis,2019/1/30,Write by Wang C.W.,8,液晶驅動原理,電極,電極,液晶,Field OFF,Field ON,2019/1/30,Write by Wang C.W.,9,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。 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。,2019/1/30,Write by Wang C.W.,10,液晶顯示器的種類,液晶 顯示器,扭轉型 (Twinst
4、 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) 1980 PDLC (Polymer Dispersive LC) 1988 PSCT (Polymer Stabilized Cholesteric Texture) 1993 Other DS (D
5、ynamic Scattering) 1968 PC (Phase Change) 1968 GH (Guest Host) 1968 ECB (Elcetrical Control Birefregency) 1971 BTN (Bistable Twist Nematic) 1995 IPS (In Plane Switch) 1995 VA (Vertical Alignment)1996,2019/1/30,Write by Wang C.W.,11,TN 型 LCDs 顯示原理,液晶分子,Field OFF,Field 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,20
6、19/1/30,Write by Wang C.W.,12,STN LCDs 顯示原理,液晶分子,Field OFF,利用液晶的雙折射 特性調變穿透光線,2019/1/30,Write by Wang C.W.,13,TN & STN 電光轉移曲線V-T Curve,100%,90%,10%,Vns STN,Vs STN,Vs TN,Vns TN,T,V,2019/1/30,Write by Wang C.W.,14,TN 與 STN 的電壓漂移,T,100%,V,STN Mode,2019/1/30,Write by Wang C.W.,15,LCDs 驅動方式,直接驅動法 (Directi
7、on 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 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,2019/1/30,Write by Wang C.W.,16,LCDs 靜態驅動法,
8、Vsig,Vc,Vs,Vc-Vs,ON,OFF,2019/1/30,Write by Wang C.W.,17,多工驅動法 (振幅選擇驅動法, APT),2019/1/30,Write by Wang C.W.,18,多工驅動法的限制,2019/1/30,Write by Wang C.W.,19,APT 驅動波形,2019/1/30,Write by Wang C.W.,20,IAPT 驅動波形,APT Addressing,IAPT Addressing,2019/1/30,Write by Wang C.W.,21,APT 與 IAPT 方式比較,APT Addressing Low V
9、oltage Segment Driver : 2D High Voltage Common Driver : 2F IAPT Addressing Offset +D for Positive Polarity Offset +F for Negative Polarity Voltage Range of Segment Driver : F+D Voltage Range of Common Driver : F+D,2019/1/30,Write by Wang C.W.,22,高容量多工驅動的對策,2019/1/30,Write by Wang C.W.,23,STN LCDs 規格
10、,Operation Voltage Vop :,Bias Ratio :,Steepness :,Selection Ratio :,2019/1/30,Write by Wang C.W.,24,STN LCDs 驅動電壓計算,If Voff=2V, N=240 rows, Then :,APT : Segment Driver : 2.96V, Common Driver : 44.40V IAPT : Segment & Common Drivers : 23.68V,2019/1/30,Write by Wang C.W.,25,STN LCDs Drivers 架構,移位暫存器(S
11、hifter Register),DCLK,串列輸入訊號,.閂鎖暫存器(Latch Register),LP,F+D,0,F-D,2D,偏,壓,位,準,DF,(HLHL.H),H,L,H,H,並列輸出,垂直訊號電極,2D,0,2D,2D,IAPT 參考電壓,IAPT 驅動 IC,2019/1/30,Write by Wang C.W.,26,灰階顯示 FRC,Frame Rate Control, FRC :,2019/1/30,Write by Wang C.W.,27,灰階顯示 PWM,Pulse Width Modulation, PWM :,2019/1/30,Write by Wan
12、g C.W.,28,灰階顯示 PHM,Pulse High Modulation, PHM :,2019/1/30,Write by Wang C.W.,29,液晶的頻率響應,2019/1/30,Write by Wang C.W.,30,Vertical Crosstalk of STN LCDs,2019/1/30,Write by Wang C.W.,31,Vertical Crosstalk 的抑制 (一),每兩條水平線變換一次驅動電壓極性,2019/1/30,Write by Wang C.W.,32,Vertical Crosstalk 的抑制 (二),採用補償驅動週期,2019/
13、1/30,Write by Wang C.W.,33,Vertical Crosstalk 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。,2019/1/30,Write by Wang C.W.,34,Horizontal Crosstalk of STN LCDs,A,B,A,B,2019/1/30,Write by Wang C.W.,35,Horizontal Crosstalk 的抑制,A,B,2019/1/30,Write by Wang C.W.,36,Frame Response of STN
14、 LCDs,2019/1/30,Write by Wang C.W.,37,Active Addressing for STN LCDs,2019/1/30,Write by Wang C.W.,38,Active Addressing 驅動電壓,If Voff=2V, N=240 rows, Then : F = 0.730 X 2V = 1.460V |G| = 0.954 X 2V = 21.909V Output Range of Segment Driver is about 44V. Common Driver of Common Driver is about 3V.,2019/
15、1/30,Write by Wang C.W.,39,Segment Voltage of Active Addressing,2019/1/30,Write by Wang C.W.,40,Active Addressing 的矩陣運算,列向量(Column),時間(Time),行向量(Row),Bit-Map Image Matrix,Row Function Matrix,時間(Time),列(Column),Column Voltage Matrix,2019/1/30,Write by Wang C.W.,41,矩陣運算方式,行(Row),行向量(Row),列向量(Column),B
16、it-Map Image Matrix,Row 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 Sequential,2019/1/30,Write by Wang C.W.,42,Column Sequential 硬體架構,2019/1/30,Write by Wang C.W.,43,Time Sequential 硬體架構,2019/
17、1/30,Write by Wang C.W.,44,主動矩陣式液晶顯示器 AM-LCDs,2019/1/30,Write by Wang C.W.,45,TFT LCDs 等效電路,Row Drivers,Column Driver,2019/1/30,Write by Wang C.W.,46,Arrangement of Color Filter,Stripe,Triangle,2019/1/30,Write by Wang C.W.,47,Pixel Structure of TFT LCDs,2019/1/30,Write by Wang C.W.,48,Cs on Common 與
18、 Cs on Gate 架構,2019/1/30,Write by Wang C.W.,49,Timing Chart of TFT LCDs,Frame Time,Gate 1 2 3 N,Time,2019/1/30,Write by Wang C.W.,50,TFT LCDs Driving Method,Column Inversion,Dot Inversion,Row Inversion,Frame Inversion,2019/1/30,Write by Wang C.W.,51,Direct Driving of TFT LCDs,DC Bias of Common,GrayS
19、cale Voltage,2019/1/30,Write by Wang C.W.,52,AC Modulation Addressing of TFT LCDs,Common Waveform,Graylevel Voltage,1Frame / 1 Line,2019/1/30,Write by Wang C.W.,53,TFT LCDs 的電光效應 Direct Addressing,2019/1/30,Write by Wang C.W.,54,TFT LCDs 的電光效應 AC Addressing,2019/1/30,Write by Wang C.W.,55,TFT LCDs D
20、riving Waveform Cs on Common (一),TFT LCD 驅動波形 (Cs on Common, Common = DC Bias),2019/1/30,Write by Wang C.W.,56,TFT LCDs Driving Waveform Cs on Common (二),2019/1/30,Write by Wang C.W.,57,TFT LCDs Driving Waveform Cs on Gate,2019/1/30,Write by Wang C.W.,58,TFT 電容效應的影響,2019/1/30,Write by Wang C.W.,59,液
21、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:,2019/1/30,Write by Wang C.W.,60,二階驅動方式的效應,Cs,Clc,Cgd,Csd,Cgs,Vct,Ch(N-1),Ch(N),Vs,垂直影像訊號,水平掃描訊號,Vg,水平掃描訊號,Vg,2019/1/30,Write by Wang C.W.,61,TFT 補償驅動法,3 Leve
22、l Addressing,4 Level Addressing,2019/1/30,Write by Wang C.W.,62,3 Level Addressing,2019/1/30,Write by Wang C.W.,63,4 Level Addressing,Vst=Vct,B(+),B(-),B(-),B(+),W(+),W(+),W(-),W(-),B(+),W(-),B(-),W(+),Vp(+),Vp(-),Vp=CgdVghl/Ct,CsVge(-)/Ct,CsVge(+)/Ct,正極性,負極性,正極性,負極性,Ct=Cs+Clc+Cgd,2019/1/30,Write by
23、 Wang C.W.,64,Cs on Gate 電壓補償方式,2019/1/30,Write by Wang C.W.,65,Comparsion of Addressing Method,2019/1/30,Write by Wang C.W.,66,Horizontal Line Crosstalk,A,B,Csc,Csc,Csc,TFT Substrate,Color Filter Substrate,2019/1/30,Write by Wang C.W.,67,Horizontal Area Crosstalk,A,B,2019/1/30,Write by Wang C.W.,68
24、,Vertical Area Crosstalk,2019/1/30,Write by Wang C.W.,69,Shading Crosstalk,2019/1/30,Write by Wang C.W.,70,Shading Crosstalk 的抑制,2019/1/30,Write by Wang C.W.,71,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。,2019/1/30,Write by Wang C.W.,72,液晶畫素邊際電場效應(一),Reverse
25、Tilt,畫素電極,鄰近電極,共通電極,VP,VL,VA,VA VL : Disclination Disappeared VP LC Threshold Voltage,Reverse Tilt,2019/1/30,Write by Wang C.W.,73,液晶畫素邊際電場效應(二),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,2019/1/30,Write by Wang C.W.,74,驅動 IC Scan Driver,Bidirectional Shift Register,Level Shift Circuit
26、,Output Buffer,G1 G2 G3 .,STVR,STVL,CPV,R/L,VDDD,VSSD,VDDA,VSSA,STVR,STVL,G1,G2,Gx,2019/1/30,Write by Wang C.W.,75,Serial In Serial Out Analog Data Driver,Multiplexer,Pro:Very simple. Fewer external connections. Con:Many analog inputs. Reduced pixel charging time. System Note : Sample clock : (Dot c
27、lock) / N, N Phases. Video Phase : N,Variation on Multiplexer Pro: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 Hold,2019/1/30,Write by Wang C.W.,76,Serial In Parallel Out Analog
28、 Data Driver (一),2019/1/30,Write by Wang C.W.,77,Serial In Parallel Out Analog Data Driver (二),Double Sample and Hold / Multi-Phase,Por : Reduced operation frequency . System Note : Video In : N Video Phase : N Shift Clock : (Dot Clock) / N.,2019/1/30,Write by Wang C.W.,78,Digital Data Driver (一),Di
29、gital-to-analog Converters,Por : Digital input. Con : Complex. Requires sufficient precision to correct for LC response variation.,Ramp In,Sampled Ramp,Por : Digital input. Programmable ramp. Con : Complex circuit. High speed digital circuits. Reduced pixel charging time.,2019/1/30,Write by Wang C.W
30、.,79,Digital Data Driver (二),1-of-n Selector,Simple DAC Pro : Digital input. Programmable external voltages. Con : Complex circuit. High speed digital circuits. Many pass gates per data line.,2019/1/30,Write by Wang C.W.,80,Digital Data Driver (三),All Digital Circuit,2019/1/30,Write by Wang C.W.,81,
31、Gamma Correction of LCD,Analog Correction : 2 3 Segment Approach. Digital Correction : External fixed voltage.,2019/1/30,Write by Wang C.W.,82,Gamma Correction Simple Case,Transmission,Voltage,2019/1/30,Write by Wang C.W.,83,The Block Diagram of the TFT LCD Module,2019/1/30,Write by Wang C.W.,84,The
32、 TFT LCD Module Type,Classified into two kinds by data driver Analog type TFT-LCD module The analog data drivers The analog interface to PC Only NEC Digital type TFT-LCD module The digital data drivers The ADC/ LVDS/PanelLink interface to PC Mainstream,2019/1/30,Write by Wang C.W.,85,The Analog Inte
33、rface,2019/1/30,Write by Wang C.W.,86,The ADC Interface,2019/1/30,Write by Wang C.W.,87,The LVDS/PanelLink Interface,2019/1/30,Write by Wang C.W.,88,Analog/ADC/LVDS/PanelLink,Analog Interface True Color Sampling Error Low Edge Sharpness Noise in the Analog Signal Transmission,2019/1/30,Write by Wang
34、 C.W.,89,Analog/ADC/LVDS/PanelLink,ADC Interface Mainstream in the Desktop LCD Monitor Interface Sampling Error Low Edge Sharpness Noise in the Analog Signal Transmission EMI Issue for High Resolution Format Low Image Quality and High Cost,2019/1/30,Write by Wang C.W.,90,Analog/ADC/LVDS/PanelLink,LV
35、DS Interface Mainstream in the Notebook PC Interface High Edge Sharpness Reducing EMI & Number of Cable Line High Image Quality and Low Cost Short Transmission Length & Low Noise Margin Compatible Issue,2019/1/30,Write by Wang C.W.,91,PanelLink Interface Application in the Desktop LCD Monitor Interf
36、ace High Edge Sharpness Reducing EMI & Number of Cable Line High Image Quality and Low Cost Second Supply Source Issue,Analog/ADC/LVDS/PanelLink,2019/1/30,Write by Wang C.W.,92,TFT 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,2019/1/3
37、0,Write by Wang C.W.,93,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,2019/1/30,Write by Wang C.W.,94,大面積高解析度 TFT LCDs 的開口率影響因素,2019/1/30,Write by Wang C.W.,95,Plasma Addressing LCDs,2019/1/30,Write by Wang C.W.,96,In-Plane-Switch Mode LCDs,2019/1/30,Write by Wang C.W.,97,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,2019/1/30,Write by Wang C.W.,98,Comparison of Liquid Crystal Modes,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,TN,IPS,VA,
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