平板显示技术C3 TFTLCD driver.ppt

1、平板显示技术TFT LCD driver,第3章 TFT LCD,TFT-LCD主要组成及关键技术 TFT LCD驱动技术 TFT LCD Design Backlight Design 液晶显示最新发展(器件结构、驱动方式等）,LCD,Physics,Electronics Driver,Ergonomics Human Factors,Production Process,Chemistry Material Science,The Block Diagram of the TFT LCD Module,The TFT LCD Module Type,Classified into two

2、 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,The Analog Interface,The ADC Interface,The LVDS/PanelLink Interface,Analog/ADC/LVDS/Pan

3、elLink,Analog Interface True Color Sampling Error Low Edge Sharpness Noise in the Analog Signal Transmission,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

4、 Format Low Image Quality and High Cost,Analog/ADC/LVDS/PanelLink,LVDS 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,PanelLink Interface Applicati

5、on in the Desktop LCD Monitor Interface High Edge Sharpness Reducing EMI & Number of Cable Line High Image Quality and Low Cost Second Supply Source Issue,Analog/ADC/LVDS/PanelLink,驱动 IC Scan Driver,Bidirectional Shift Register,Level Shift Circuit,Output Buffer,G1 G2 G3 .,STVR,STVL,CPV,R/L,VDDD,VSSD

6、,VDDA,VSSA,STVR,STVL,G1,G2,Gx,Row driver,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 clock) / N, N Phases. Video Phase : N,Variation on Multiplexer Pro:Video In

7、put. 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,Serial In Parallel Out Analog Data Driver (一),Serial In Parallel Out Analog Data Driver (二),Double Sample and Hold / Multi-Phase,Por :

8、Reduced operation frequency . System Note : Video In : N Video Phase : N Shift Clock : (Dot Clock) / N.,Digital Data Driver (一),Digital-to-analog Converters,Por : Digital input. Con : Complex. Requires sufficient precision to correct for LC response variation.,Ramp In,Sampled Ramp,Por : Digital inpu

9、t. Programmable ramp. Con : Complex circuit. High speed digital circuits. Reduced pixel charging time.,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.,Digital Da

10、ta Driver (三),All Digital Circuit,Typical column driver block diagram,Column driver block diagram,Gamma correction,Gamma reference,Gamma and column driver,Gate Pulse 的传输延迟,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。,Row pulse delay,Signal propagation,Reduced row pulse delay r

11、equired,CPU,Signal,On the Glass Substrate,Integration,【a-Si LCD】,Driver IC,Controller IC,RAM,Power supply IC,【System LCD】 Poly-Si,Peripheral Function Parts,1.Color TFT LCD PANEL Configuration a) Panel Configuration and Resolution,Resolution,Pixel Arrangement,Sub-Pixel,Screen Ratio,Screen Size (for c

12、ommercial products),640 480,800 600,VGA,SVGA,XGA,SXGA,UXGA,QXGA,1024 768,1280 1024,1600 1200,1920 1080,2048 1536,921,600,1,440,000,2,359,296,3,932,160,5,760,000,6,220,800,9,437,184,4 : 3,4 : 3,4 : 3,5 : 4,4 : 3,16 : 9,9.5”, 10.4”,10.4”, 11.3”, 12.1”,12.1”, 13.3”, 14.1”, 15.1”,14.1”, 15.7”, 18.1”, et

13、c.,20.1”, etc.,DCLK (60Hz),25MHz,40MHz,65MHz,93/112MHz,133/160MHz,Remarks,Pixel,R,G,B,R,G,B,R,R,G,B,R,G,B,R,R,G,B,R,G,B,R, Arrangement of Vertical Stripe, Resolution,Figure 3 Configuration diagram 1,HDTV,4 : 3,Unfinished VESA Standard,133/160MHz,211/265MHz,2. Understanding How to Drive TFT-LCD The L

14、CD is the display element using the liquid crystal and is improved by varied technologies for high video quality and applied technologies are described. 1) Polarity Inversion Method The Polarity of Applied voltage should be periodically inverted in order to prevent the specific heat, which is genera

15、ted if DC voltage is applied to the liquid crystal for a long time. It is called the Polarity Inversion Method. a) Frame Inversion It is the method that allows the polarity of data voltage, which is permitted to the liquid crystal for common electrode voltage, to be identified by frame unit. As figu

16、re 10 shows, if the data voltage of positive polarity is permitted to the Even Frame, the data voltage of negative polarity is permitted to the Odd Frame. - The consumption of current generated by switching is small. - It is sensitive to the Flicker phenomenon by permeability dissymmetry of positive

17、 polarity and negative polarity. - It is weak to Crosstalk by interference among data. b) Line Inversion It is the Polarity Inversion Method generally used for low resolution (VGA, SVGA, etc.) and allows data voltage to vary the pixel polarity by horizontal line unit. As figure 11 shows, if the posi

18、tive polarity and negative polarity are respectively permitted to the odd line and even line, the polarity of voltage is permitted by contraries on the next frame. - The flicker of luminance deflection between lines by spatial averaging is small compared with Frame Inversion because the voltage of o

19、pposite polarity is permitted between closed lines - Coupling phenomenon generated among data is offset because the voltage of opposite polarity is distributed to the vertical direction. So Vertical Crosstalk is small compared with Frame Inversion. - The voltage of same polarity is distributed to th

20、e horizontal direction, so Horizontal Crosstalk is generated. - The number of repeated switching increases compared with Frame Inversion, so consumed current also increases.,c) Column Inversion It is the method that the polarity of permitted data voltage is identified to the vertical direction as fi

21、gure 11 shows and the voltage of opposite polarity is permitted to the horizontal direction. - As Line Inversion, Flicker phenomenon is small by spatial averaging compared with Frame Inversion. - Horizontal Crosstalk is small compared with Frame Inversion. - Column Drive IC for high voltage should b

22、e used because the data voltage of opposite polarity should be permitted between closed lines to the vertical direction compared with common electrode voltage. d) Dot Inversion It is the method that realizes the most excellent video quality and is applied to high resolution (XGA, SXGA, UXGA, etc.).

23、As figure 12 shows, the polarity of data voltage between closed pixel is the reverse in all directions. - Flicker phenomenon can be minimized by spatial averaging. - Column Drive IC for high voltage should be used. - Current is consumed so much.,Odd Frame,Even Frame, Dot Inversion, Column Inversion,

24、 Line Inversion, Frame Inversion,2) Pixel Driving Method High voltage driving method and low voltage driving method among methods for driving unit pixel are described as follows. a) High Voltage Driving It is the method generally used for Dot Inversion and the same data line, that is, Output Channel

25、 of Column Drive IC drives positive and negative polarity respectively. Polarity is divided into positive polarity area of high voltage and negative polarity area of low voltage with Vcom of voltage. Then Column Drive IC drives with high voltage.Refer to Vcom section of Chart 1.14 and Gamma section

26、of Chart 1.15. b) Low Voltage Driving It is the method generally used for Line Inversion and drives common electrode voltage and data permitted voltage to the opposite phase each other by AC. Refer to Vcom section of Chart 1.14 and Gamma section of Chart 1.15. 3) Panel Driving Method a) Analog Drive

27、 Method It is the method that directly uses analog voltage, which is the form video data entered, for liquid crystal driving voltage. The serial analog signals display all natural colors and simple circuit configuration is possible because just 3 signal lines are used. However, velocity is very slow

28、 (about 5MHz20MHz) and Chip die is large, so it is too expensive to develop IC for compact OA and applicability is not so good. b) Digital Drive Method The form of video data entered is digital voltage and Column Drive IC passes the digital-to-analog converter in order to drive the panel. The number of colors which can be displayed depends on the number of digital bit. Now this method is generally appl