液晶屏知识简介.ppt
液晶屏知识简介The Brief Introduction For LCD Panel,培训目的Targets,1、熟悉液晶显示屏的基本结构 To know the basic configuration of LCD panel2、掌握液晶显示屏各接口的意义 To handle the meanings of each port3、掌握液晶显示屏工作条件 To handle the working conditions of LCD panel4、熟悉液晶屏的常见故障 To know the general fault on LCD panel,目录Contents,1、液晶屏的基本组成The basic configuration of LCD panel2、液晶屏接口的意义The meanings of LCD panels ports 3、液晶屏的工作条件The working conditions of LCD panel4、液晶屏的常见故障The general fault on LCD panel,一、液晶屏的基本组成Basic configuration,所有的液晶屏（TFT-LCD）都包括：All TFT-LCD panel includes:显示屏单元 Panel unit TFT驱动板 TFT driving board 背光板 Backlight board,冷镜,色轮,光源,屏幕,投影镜头,处理器,存储器,光学,1、显示屏单元Panel unit,液晶基片：主要由液晶、TFT、TFT电极、彩色滤光片、玻璃基板和偏光片等组成。Liquid Crystal Module:Consist of Liquid crystal,Thin Film Transistor,TFT electrode sheets,Color filter sheet,Glass sheets and Polarizing filter.,光源模组：主要由灯管、反射板、导光板、散射板、棱镜片和保护膜等组成。Light source module:consist of CCFL,Reflection sheet,Light Guide Plate(LGP),Diffuser sheet,Prism sheets and Protection sheet.,2、TFT驱动板TFT Driving board主要包括：输入信号连接器、时序控制器、帧缓冲器、DC-DC转换及基准电压、扫描驱动IC和数据驱动IC等。Including:Input connector,Timing controller,Frame buffer,DC-DC converter&reference voltage,Scan driver IC and Data driver IC.,3、背光板Backlight board主要包括：输入连接器、背光控制IC、N沟道双MOSFET、变压器、输出连接器和检测保护电路等。Including:Input connector,Inverter controller,N-channel dual MOSFET,Transformer,Output connector,Over current&voltage detection and protection.,4、液晶屏的拆解Disassemble the panel unit（以奇美27寸屏为例take example for 27-inche CHIMEI panel）,拆去背光板屏蔽罩后轻轻拔掉7个灯管插头和一个公共插头，拿开背光板。Disassemble the backlight shield and put off the plugs,then remove the backlight board.,拆去TFT驱动板屏蔽罩Disassemble the TFT driving board shield.,拆去TFT驱动板排线Disassemble the TFT driving board cables.,拿开TFT驱动板Take away the TFT driving board.,将液晶屏翻转过来，拆去屏框上的10颗螺钉Overturn the panel unit,disassemble the 10 screws on the frame.,将屏框拆掉后After disassembled the frame.,拆去接口板上的螺钉Remove the screws on the circuit board.,将液晶板翻起，并拿开Put up the panel unit and remove it.,背光源组件Backlight source module.,将背光源组件翻转过来，撕开黑胶纸。Overturn the backlight module,rive off the black tape.,用一字起轻轻撬开卡扣Lightly prize up the fasteners with a screwdriver.,翻起反射板，可以看到灯管CCFLPut up the reflection sheet,the CCFLs appear.,完整的灯管排列All the CCFLs.,CCFL简介,CCFL是Cold Cathode Fluorescent Lamp的简称，意思是冷阴极荧光灯。是采用冷阴极代替钨丝等热阴极的低气压汞-稀有气体放电灯，在强电场的作用下，依靠离子轰击由镍钽和锆等金属组成的电极来发射电子，使汞原子激发和电离，形成丰富的253.7nm紫外线和足够的电流，紫外线辐射再激发管壁上的荧光粉涂层而发光。,CCFL的工作电压：500V1000V（通常为800V）CCFL的工作频率：40Kz80Kz（通常为60Kz）CCFL的特性：1、高亮度，高效率，低能耗，长寿命 2、防震性能好，重复亮灯熄灭的性能卓越 3、使用特殊气体，可以在低温下自如启动 4、发热量低且管径细小,用一字起轻轻撬开灯管排座上的卡扣Prize up the fasteners on the CCFL socket with a screwdriver.,拿开灯管排，散射板就可以翻起来Remove the CCFLs carefully,the diffuser sheet can be put up。,棱镜片,棱镜组和保护膜Prism sheets and protection sheet.,二、液晶屏外部接口的意义The meanings of LCD panels external ports（一）、液晶屏的外部接口 LCD Panel external ports背光板接口 Backlight board portsTFT驱动板接口 TFT driving board ports,1、背光板接口 Backlight board ports,背光板供电Power Supply 由电源板提供，电压一般5V24V，目前用得较多的为24V。Provided by power board,voltage from 5V to 24V,now the 24V is popular.背光开关控制Backlight on/off control从数字板送来，一般高电平开，低电平关。Sent from digital board,usually high level is ON,low is OFF.亮度控制Bright control亮度控制信号为数字PWM信号，从数字板送来，频率一般为30Hz200Hz。The bright control signal is a digital PWM waveform from digital board,its frequency is 30Hz to 200Hz.,2、TFT驱动板接口TFT driving board ports电源和地Power and Ground 由数字板提供，通过数据线向TFT驱动板供电。目前常用的液晶屏电压有两种，一种是5V，如奇美屏；一种是12V，如LG屏。Provided by digital board with a data cable,supply to TFT driving board.now there are two kinds of voltages used by the panel,one is 5V,such as CHI MEI,another one is 12V,such as LG.,TFT驱动板数据接口TFT driving board data ports,（1）、TFT-LCD的数据接口种类Types of data port：单TTL6位（8位）Single TTL 6-bit(8-bit)双TTL6位（8位）Dual TTL 6-bit(8-bit)单LVDS6位（8位）Single LVDS 6-bit(8-bit)双LVDS6位（8位）Dual LVDS 6-bit(8-bit)单TMDS6位（8位）Single TMDS 6-bit(8-bit)双TMDS6位（8位）Dual TMDS 6-bit(8-bit)还有最新出来的标准RSDS 目前液晶电视采用的接口是：双TTL8位、单LVDS8位和双LVDS8位。Now the popular ports are Dual TTL 8-bit,Single LVDS 8-bit and Dual LVDS 8-bit.,（2）、位数的含义The meanings of Bits6位和8位是用来表示屏能显示颜色多少。6位屏可以显示颜色为 2的6次方X2的6次方X2的6次方分别代表R G B 三基色，算下来6位屏最多可以显示的颜色为262144种颜色，8位屏为16777216种颜色。8-bit panel can show 16.777216 million kinds of color.,（3）、TTL接口TTL PortTTL信号是TFT-LCD惟一能识别的标准信号，早期的数字处理芯片输出的都是TTL信号，可以直接驳接到TFT-LCD。,（4）、TTL接口的缺陷The failing of TTL由于TTL信号电平有3V左右，对于高速率的长距离传输影响很大，且抗干扰能力也比较差，所以只适用于显示分辨率较低的TFT-LCD，如640*480、800*600。要显示更高分辨率，则采用了LVDS。As TTL signal is around 3V,transmission is difficult for high speed and long distance,and its anti-interference ability is poor,so TTL port only used in low definition TFT-LCD,for example,640*480,800*600,higher definition TFT-LCD used LVDS port.,（5）、什么是LVDS？Whats the LVDS?LVDS是Low Voltage Differential Signaling的缩写，意思是低压差分信号。工作原理是用一颗专门的IC，把输入的TTL信号编码成LVDS 信号，单6位为4组差分，单8位为5组差分，数据线名称为D0-D0+D1-D1+D2-D2+CK-CK+D3-D3+，其中如果是6位屏就没有D3-D3+这一组信号，这个编码过程是在数字板上完成的，新的数字处理IC已经把编码IC集成在内部了。在屏的另一边，也有一颗相同功能的解码IC，把LVDS信号变成TTL信号，屏最终用的还是TTL信号。因为LVDS信号电平为1V左右，而且-线和+线之间的干扰还能相互抵消，所以抗干扰能力非常强，很适合用在高分辩率所带来高码率的屏上。,数字处理IC Digital IC,LVDS编码IC LVDS Encoder,LVDS解码IC LVDS Decoder,TFT-LCD,数据线Cable,TTL,LVDS,TTL,LVDS传输 LVDS Transmission,TCL高清屏（1366*768）均为单8位LVDS传输，包括8位数据，2位时钟共10条数据线。D0-D0+D1-D1+D2-D2+CK-CK+D3-D3+,（6）、单LVDS传输的不足 The failing of single LVDS单LVDS能传输分辨率较高的数据信号，抗干扰能力也较强，但要显示1400X1050（SXGA+）、1600X1200（UXGA）、1920X1080或更高分辩率，由于信号的码率相应提高，单路LVDS传输已不堪重负，所以目前都用双路LVDS接口，一路奇数LVDS，一路偶数LVDS，以降低每一路LVDS的速率，保证信号的稳定度。The single LVDS will be failed when it transmission a higher definition data,such as 1920*1080,so a dual LVDS is used instead of it now.,TCL全高清屏（1920X1080）均为双路LVDS传输，包括8位奇数据，8位偶数据，2位奇时钟和2位偶时钟，共20条数据线。DA0-DA0+DA1-DA1+DA2-DA2+CKA-CKA+DA3-DA3+DB0-DB0+DB1-DB1+DB2-DB2+CKB-CKB+DB3-DB3+All TCL full definition Panels(1920*1080)have dual LVDS transmission,it includes 8-bit odd data,8-bit even data,2-bit odd clock and 2-bit even clock with 20-wire data cable.,（7）、LVDS的信号格式LVDS Format 目前用于TFT-LCD上的LVDS信号格式有两种：There are two LVDS formats being used now:VESA（Video Electronic Standard Association）格式。它是美国视频电子标准协会制定的标准。JEIDA（Japan Electronic Industry Development Association）格式。它是日本电子工业发展协会制定的标准。,（8）、LVDS格式选择端口LVDS Option目前多数厂商生产的TFT-LCD都支持这两种格式，在TFT驱动板接口上留有一个LVDS选择端，通过这个端口加上高低电平来适应数字板不同的LVDS信号格式输出，该端口开路时即为屏的默认格式。TCL所使用的屏中，除三星SS屏的默认格式是JEIDA外，其它如LG、奇美CM、友达AU、中华CH、广辉QDI等屏的默认格式是VESA。A lot of manufacturers panel supports these two formats by selecting the voltage of LVDS option port.,特性,种类,尺寸Size,工作电压Voltage,分辨率Definition,格式选择端LVDS Option,LG,SS,QDI,CH,AU,CM,26,32,37,42,23,26,32,40,46,26,32,37,37,27CM0,27CM1,30CM0,27CM2/3,32CM0,32CM1,12V,5V,12V,12V,12V,5V,5V,1366*768,1366*768,1366*768,1366*768,1366*768,1366*768,1280*720,9,21,9,27,9,3,Nil,（9）、显示旋转端口 Display Rotation有些屏具有这个端口，如奇美屏。在该端口接上选择电平，可以使显示的图像上下左右180度旋转，以适应特殊的显示场所，该端口开路时即为默认值。Some panels have got this port,such as Chi Mei panel.The picture will be rotated up/down and left/right with 180 degrees when the port has been got a option voltage.Its a default while the port open.,（10）、帧频选择端口Frame rate selection,有些屏具有这个端口，如奇美屏。在该端口接上选择电平，可以使屏的显示频率在50Hz和60Hz帧频进行选择，以适应输入信号的帧频。如果该端口的选择电平错误，屏的显示频率和输入信号的帧频不相同，则会出现无显示的故障。,三、液晶屏的工作条件The working conditions of LCD panel,（一）、背光组件Backlight module,1、必须有24V的背光电源24V backlight power supply2、必须有背光控制信号（一般为高电平点亮）Backlight control signal3、亮度控制信号（无亮度控制信号CCFL也能被点亮，但亮度不受控）Brightness control signal,（二）、TFT驱动组件TFT driving module,1、必须有5V或12V屏供电5V or 12V power supply2、TFT驱动板接口数据和时钟线必须正确，否则无图像或图像不正常Data cable should be right3、LVDS格式必须与屏相匹配，否则图像显示不正常。如JEIDA格式信号输入到LG屏（默认格式VESA）时，图像噪波很大LVDS format should be right,四、液晶屏常见故障The general fault on LCD panel,1、黑屏，背光不亮。可能的原因有：Black panel,no backlight.The possible reasons are as follows:背光板无24V供电No 24V supply to backlight board背光板无背光控制信号（高电平）No backlight control signal(high level)to backlight board背光板本身故障Backlight board failed液晶屏某支灯管故障，引起背光板保护One CCFL failed,the backlight board entries protection condition,2、黑屏，背光亮。可能的原因有：Black panel,backlight works.The possible reasons are as follows:数字板故障Digital board failedTFT驱动板无供电No power supply to TFT driving board数字板至液晶屏数据线The data cable failedTFT驱动板故障TFT driving board failed,3、图像有竖线或横线。可能的原因有：液晶片与接口板间的导电膜接触不良，引起某列或某行的TFT截止TFT驱动板故障,THANKS!,April,2007,
