TFT LCD screen display

Photoelectric properties of liquid crystals

Due to the structure of the liquid crystal molecules for different parties (Anisotropic), so caused by the photoelectric effect will vary because of different direction, in short, that is, the liquid crystal molecules in the dielectric coefficient and refractive index, and so on photoelectric properties have different sex, so we can use these properties to change the intensity of the incident light, so that the formation of gray-scale, to apply on the display component. The most important characteristic of liquid crystal is its dielectric coefficient and refraction coefficient. The dielectric coefficient is the property of liquid crystal to be influenced by electric field, and the refraction coefficient is an important parameter to influence the path of light when it passes through liquid crystal. And liquid crystal display is to use these characteristics of liquid crystal itself, the appropriate use of voltage, to control the rotation of liquid crystal molecules, and then affect the direction of light travel, to form different gray scales, as a display tool.

TFT LCD screen display principle

TFT LCD is also known as thin-film transistor liquid crystal displays (TFT), and we mention that liquid crystal displays require voltage control to produce gray scales. Displays that use thin-film transistors to generate voltage to control the liquid crystal steering are called TFT LCDS. In the section structure, the liquid crystal is inserted between the upper and lower layers of glass, providing a parallel plate capacitor, called CLC(capacitor of liquid Crystal). It is about 0.1pf in size, but in practice, the capacitor does not hold the voltage until the next screen data update. This means that when the TFT charges the capacitor, it does not hold the voltage until the next TFT charges it (at a normal 60Hz screen update frequency, it takes about 16ms to hold it). As a result, the voltage changes and the grey scale displayed is incorrect. Therefore, in the design of the plate, another storage capacitor, CS(approximately 0.5PF), is added, allowing the charged voltage to remain in the screen until the next update. But correctly, the TFT itself, which grows on glass, is just a switch made from a transistor. Its main job is to determine whether the voltage on the LCD Source driver should be charged to this point. The voltage to be charged at this point is determined by the external LCD source driver.