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按一下以編輯母片標題樣式,按一下以編輯母片文字樣式,第二層,第三層,第四層,第五層,P.,34,TFT-LCD,模组,結構組成,TFT-LCD,工作原理,TFT-LCD,製作流程簡介,TFT-LCD,光學規格介紹,TFT-LCD,簡介及光學規格介紹,T,hin,F,ilm,T,ransistor,L,iquid,C,rystal,D,isplay,薄膜電晶體液晶顯示器,Whats TFT-LCD,The thin-film transistor liquid crystal display (TFT-LCD) is a cutting-edge display, which screens picture information by adjusting the amount of light permitted. TFT is a circuit formed with semiconductor films on a thin glass substrate to control liquid crystals. This circuit plays a vital role in controlling each pixel, the basic unit of a picture image. The color filter displays a color image by coating the pixel (red, green and blue) on a glass substrate.,Driver IC,Cell,TFT-LCD,panel,Backlight,Front view,Back view,X-PCB,Lamp Connector,Driver IC,Timing Controller,Signal Interface,Y-PCB,LVDS receiver,TFT-LCD,模组,結構組成,关于液晶,1888,年，澳大利亚植物学者莱尼茨尔（,Reinitzer,）研究胆甾醇在植物中的作用时，用胆甾基苯进行试验，无意间发现了液晶，但液晶的实际应用直到二十世纪五十年代才开始。 顾名思义，液晶是固液态之间的一种中间类状态。 液晶是一种有机化合物，在一定的温度范围内，它既具有液体的流动性、粘度、形变等机械性质，又具有晶体的热（热效应）、光（光学各向异性）、电（电光效应）、磁（磁光效应）等物理性质。 光线穿透液晶的路径由构成它的分子排列所决定。人们发现给液晶充电会改变它的分子排列，继而造成光线的扭曲或折射。 液晶按照分子结构排列的不同，分为三种：晶体颗粒粘土状的称为近晶相（,Smectic,）液晶、类似细火柴棒的称为向列相（,Nematic,）液晶、类似胆固醇状的称为胆甾相（,Cholestic,）液晶。这三种液晶的物理特性都不尽相同，用于液晶显示器的是第二类的向列相（,Nematic,）液晶,TFT-LCD,工作原理,A pixel, the smallest unit to indicate a picture image, is formed by three sub-pixels consisting of red, green, and blue. The number of pixels arranged in a display determines the resolution of the TFT-LCD. TFT is composed of the data line (image signal transfer) and gate line (TFT on/off signal transfer).,TFT existing in each sub-pixel controls the voltage difference between the TFT glass electrode and the color filter glass electrode in order to adjust the molecular array of liquid crystals. Such a change in the molecule direction of liquid crystals alters the amount of light penetrating the liquid crystal layer. Consequently, the TFT-LCD display shows picture image information.,TFT-LCD,工作原理,液晶是一种有机复合物，由长棒状的分子构成。在自然状态下，这些棒状分子的长轴大致平行。,LCD,第一个特点是必须将液晶灌入两个列有细槽的平面之间才能正常工作。这两个平面上的槽互相垂直,(90,度相交,),，也就是说，若一个平面上的分子南北向排列，则另一平面上的分子东西向排列，而位于两个平面之间的分子被强迫进入一种,90,度扭转的状态。由于光线顺着分子的排列方向传播，所以光线经过液晶时也被扭转,90,度。但当液晶上加一个电压时，分子便会重新垂直排列，使光线能直射出去，而不发生任何扭转。,LCD,的第二个特点是它依赖极化滤光片和光线本身，自然光线是朝四面八方随机发散的，极化滤光片实际是一系列越来越细的平行线。这些线形成一张网，阻断不与这些线平行的所有光线，极化滤光片的线正好与第一个垂直，所以能完全阻断那些已经极化的光线。 只有两个滤光片的线完全平行，或者光线本身已扭转到与第二个极化滤光片相匹配，光线才得以穿透。,LCD,正是由这样两个相互垂直的极化滤光片构成，所以在正常情况下应该阻断所有试图穿透的光线。但是，由于两个滤光片之间充满了扭曲液晶，所以在光线穿出第一个滤光片后，会被液晶分子扭转,90,度，最后从第二个滤光片中穿出。另一方面，若为液晶加一个电压，分子又会重新排列并完全平行，使光线不再扭转，所以正好被第二个滤光片挡住。总之，加电将光线阻断，不加电则使光线射出。当然，也可以改变,LCD,中的液晶排列，使光线在加电时射出，而不加电时被阻断。但由于液晶屏幕几乎总是亮着的，所以只有,加电将光线阻断,的方案才能达到最省电的目的。,TFT-LCD,工作原理,TFT-LCD,工作原理,TFT-LCD,製作流程,TFT-LCD,製作流程,TFT Process,TFT-LCD,製作流程,TFT Process,TFT-LCD,製作流程,TFT Process,process and processing steps are quite similar to that of the semiconductor industry. Deposition, photolithography and etching steps are common to both industries. The key differences are that the TFT is built on a glass substrate instead of a silicon wafer. In addition, the TFT requires a processing temperature ranging from approximately 300 to 500? compared to about 1,000?required for semiconductor fabrication.,1. PECVD (Plasma Enhanced Chemical Vapor Deposition) Process,Before gas enters the chamber, the state of the vacuum is maintained and the glass plate is heated to a specific temperature. When gas flows into the chamber, the RF voltage is applied from electrodes inside the chamber, which transform gas into a plasma state. From this plasma, precursors are formed and deposited on the glass substrate.,2. Sputtering Process,Sputtering is the process wherein the gas ion, which is the high energy inside the plasma created by RF power or DC power collides with the target surface, resulting in the deposition of the target material on the plate. Generally, the target materials are mounted on the negative electrode surface. Then, the sputtered target materials are deposited on the plate, which is put on the positive electrode. For sputtering, inactive gases are used, such as helium and argon, so that deposition material chemistry is not affected.,3. Photolithography Process,Photolithography is the transfer of a pattern from the photo mask onto a substrate. The photolithography process begins when the substrate is coated with an extremely thin liquid film of photosensitive material, called,photoresis,. The light then exposes the,photoresist, some of which is destroyed when exposed to the light. The unnecessary portion of the material is then cleaned from the surface through another process, leaving an extremely fine pattern behind. Another layer of the,photoresist,is then deposited to the substrate, exposed, cleaned, until all the layers have been printed or imaged onto the surface. The photolithography process is a critical step within the LCD manufacturing process because panel quality depends on the entire pattern formation. As such, it is extremely sensitive to particles and other forms of contamination. Thus, this process requires a special clean environment, commonly referred to as a clean room, and precise control of equipment, chemicals and materials. In the future, this will prove increasingly important as advanced displays that offer greater functionality and higher performance will require increasingly complex and stringent manufacturing capabilities.,4. Dry etch Process,The dry etch process uses reactive species, such as atoms or radicals from the gas plasma, to etch away a portion of the object material. When these species react with the material located on the plate, the open region of material transforms into a volatile state and is removed from the matrix. In this process, the reaction velocity is fast and fine patterns can be formed uniformly.,TFT-LCD,製作流程,Color Filter Process,TFT-LCD,製作流程,Cell Process,LCD production process can be described as follows:(1) the orientation layer on the lower and upper plate is formed;(2) the layer is properly positioned so that the liquid crystal can properly align; (3) the spacer is dispensed, the seal is printed, and the two plates are assembled; (4) the liquid crystal is injected into the cell through the capillary effect; and (5) the injection hole is sealed.,1. Printing the Orientation Layer,The orientation layer is evenly spread on the pixel area of the upper and lower plate. The polyimide is spread on the drum thinly and evenly and is coated on the rubber plate, which has been patterned in advance. In turn, the polyimide is printed on the upper color filter or the lower TFT-array plate. After printing, the polyimide is hardened through the process of annealing.,2. Rubbing,Rubbing,is the process that forms the straight groove on the hardened polyimide in a fixed direction in order to make the liquid crystal orient in a fixed direction. The straight groove can be formed by rubbing the panel in a certain direction with the rubbing velvet attached to the rotating drum.,3. Dispensing Spacers,The spacers are dispensed evenly in order to secure the fixed cell gap when assembling the upper and lower plate. After the spacers are mixed in the liquid with the proper concentration, they are then transported to the spray nozzle through the pump, and subsequently sprayed on the surface of the plate from the nozzle with high pressure. Heating dries the liquid, and the density of the spacer is adjusted between 100 ea/ and 200 ea/ according to the display size. The spacer shape is like a ball with a diameter size between 4 and 5 which determines the cell gap between the plates.,4. Injecting the Liquid Crystal,The liquid crystal is injected between the upper and lower plate using capillary action and pressure differences after the upper and lower plate are assembled. The process system consists of a vacuum pump, vacuum chamber, an up/down moving device, a jig, which contains the liquid crystal, and, an N system. At first, the internal cell vacuum level is maintained at about 10-3,Torr,from the original vacuum state. The liquid crystal is then pulled into the cell by the capillary effect. When the cell is filled with liquid crystal up to about 80 percent ,N?s,then purged into the vacuum chamber slowly and the liquid crystal fills the remaining space in the cell as a result of the difference in pressure from inside and outside the cell.,TFT-LCD,製作流程,Module Process,The module process is the step that determines the final quality of the product to be delivered to the customer. The step is completed once the polarizer, the drive IC, PCB, backlight unit and the frame are assembled.,亮度,Luminance(cd/m,2,),TFT-LCD,重要光學規格,10mm,10mm,10mm,10mm,1/4 H,1/2 H,3/4 H,1/4 V,1/2 V,3/4 V,Y,1,Y,11,Y,5,Y,4,Y,2,Y,12,Y,13,Y,8,Y,7,Y,6,Y,3,Y,9,Y,10,a.,規格條件,：,(1),中心點,(2),五點平均,b.,影響亮度的因素,(1) Cell,穿透率,(,开口率,),(2) Gamma Curve,(3) BL,發光效率,(4),燈管電流,2.,對比,度,Contrast Ratio,(CR),TFT-LCD,重要光學規格,Luminance of all pixels White(L255),Luminance of all pixels Dark(L0),L255(or L63),L0,CR=,3.,分辨率,TFT-LCD,重要光學規格,LCD,的最大分辨率就是它的真实分辨率，也就是最佳分辨率。,4. Viewing Angle,(,可视角,),TFT-LCD,重要光學規格,CR10 (W/B),液晶显示器的可视角度包括水平可视角度和垂直可视角度两个指标,：,水平可视角度表示以显示器的垂直法线,(,即显示器正中间的垂直假想线,),为准，在垂直于法线左方或右方一定角度的位置上仍然能够正常的看见显示图像，这个角度范围就是液晶显示器的水平可视角度；同样如果以水平法线为准，上下的可视角度就称为垂直可视角度。一般而言，可视角度是以对比度变化为参照标准的。当观察角度加大时，该位置看到的显示图像的对比度会下降，而当角度加大到一定程度，对比度下降到,101,时，这个角度就是该液晶显示器的最大可视角。一般主流,LCD,的可视角度为,120160,度。比较理想的可视角度应在,1,75,度以上（水平,).,TFT-LCD,重要光學規格,带宽是指每秒钟扫描过的图像点的个数，以,MHz(,兆赫兹,),为单位，表明了显示器电路可以处理的频率范围。,让我们举例说明。比如，在标准,VGA,方式下，如果刷新频率为,60Hz,，则需要的带宽为,64048060,18.4MHz,；在,1024768,的分辨率下，若刷新频率为,70Hz,，则需要的带宽为,55.1MHz,。以上的数据是理论值，实际所需的带宽要高一些。,早期的显示器是固定频率的，现在的多频显示器采用自动跟踪技术，使显示器的扫描频率自动与显示卡的输出同步，从而实现了较宽的适用范围。,带宽的值越大，显示器性能越好。,带宽,6.,Response Time,(,响应时间,),响应速度的时间单位是毫秒（,ms,），指的是象素由亮转暗并由暗转亮所需的时间。这个数值越小越好，数值越小，说明反应速度越快。,Tr,= 90% 10% (Luminance),Tf,= 10% 90% (Luminance),TFT-LCD,重要光學規格,Time,7.,色彩,肉眼分辨的色彩为,65000,色,.,称之为全彩,.,显示色彩的多少同驱动,IC,的处理能力直接相关,.,色彩值,=2,的,n,次方,(R),* 2,的,n,次方,(G)* 2,的,n,次方,(B),如,:,26,万色,=,2,的,5,次方,(R),* 2,的,5,次方,(G)* 2,的,5,次方,(B),1677,万色,=,2,的,8,次方,(R),* 2,的,8,次方,(G)* 2,的,8,次方,(B),TFT-LCD,重要光學規格,8. Saturation,TFT-LCD,重要光學規格,在,CIE,色座標圖上,RGB,三個座標值可構成一個三角形,此三角形面積與標準定義之三角形面積做比較,此三角形面積越大,(,佔標準定義之三角形面積,百分比越高,),可以說,RGB,的色彩表現越飽和,9. Cross Talk,TFT-LCD,重要光學規格,L31 or L127,L0,L,Lb,只有當,TFT,是在開啟（,ON,）,的狀態下，液晶畫素才可以被資料驅動線上的影像電壓訊號影響，經由,TFT,對液晶畫素充放電；若是,TFT,在關閉（,OFF,）,的狀態下，理論上液晶畫素是與外部其他的電極或是液晶畫素隔絕，所以不會受到其他部分訊號變化的影響。但是，,TFT,並不是一個優良的電子開關，在,TFT,關閉的狀態下仍然會有漏電流的產生。,Q&A,End,Thanks,
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