TFT(Thin Film Transistor) Technical analysis
Date:2019-08-16
The application market of LCD has great potential. In terms of LCD panel production capacity, the main LCD production bases in the world are concentrated in Taiwan, South Korea and Japan. It can be said that Asia is the center of LCD panel R & D and manufacturing, while the development of Taiwan, Japan and South Korea are different.
At present, the mainstream technology of LCD is TFT panel technology a-Si (amorphous silicon thin film transistor). TFT (thin film transistor) LCD is a kind of active matrix liquid crystal display (am-lcd).
Different from TN technology, TFT display adopts "back transparent" illumination mode - the imaginary light source path is not from top to bottom like TN liquid crystal, but from bottom to top. In this way, a special light tube is set on the back of the liquid crystal, and the light source is transmitted upward through the lower polarizing plate. Because the electrodes of the upper and lower interlayer are changed into FET electrode and common electrode, the performance of liquid crystal molecules will also change when the FET electrode is turned on. The purpose of display can be achieved by shading and transmitting light, and the response time is greatly improved to about 80ms. TFT is commonly known as "true color" because it has higher contrast and richer colors than TN-LCD and faster screen update frequency.
Compared with DSTN, the main feature of TFT-LCD is to configure a semiconductor switching device for each pixel. Each pixel can be directly controlled by point pulse. Therefore, each node is relatively independent and can be controlled continuously. This design method not only improves the response speed of the display, but also can accurately control the gray level of the display, which is the reason why TFT color is more realistic than DSTN.
At present, the vast majority of notebook computer manufacturers use TFT-LCD. The early TFT-LCD was mainly used in the manufacture of notebook computers. At that time, TFT had great advantages over DSTN, but due to technical reason
TFT liquid crystal has a semiconductor switch for each pixel, and each pixel can be directly controlled by point pulse, so each node is relatively independent and can be continuously controlled, which not only improves the reaction speed of the display screen, but also precisely controls the display color level, so the color of TFT liquid crystal is more true.
TFT LCD is characterized by good brightness, high contrast, strong sense of hierarchy and bright color, but it also has the disadvantages of high power consumption and high cost.
TFT LCD technology accelerates the development of mobile phone color screen. Many of the new generation of color screen mobile phones support 65536 color display, and some even support 160000 color display. At this time, the advantages of high contrast and rich color of TFT are very important.
