NEWS

What is the LCD panel made of?

09.27.2023

The LCD panel is mainly composed of glass substrates, polarizers, color filters, liquid crystal materials, alignment films, casings, optical diaphragms, drive circuits, and other components.

 

1. Glass Substrate

A glass substrate is actually a thin glass sheet with a flat surface. A layer of In2O3 or SnO2 transparent conductive layer evaporated on the surface is the ITO film layer, which is made into a transparent conductive pattern after photolithography and processing. These graphics are composed of the minimum image unit of all chromaticity and brightness of an image, pixel graphics and external lead graphics. Therefore, the outer leads must not be soldered in the traditional way, and can only be connected through conductive rubber strips or conductive tape. If it is scratched, cut or corroded, the device will be scrapped.

2. Color Filter

The reason why the LCD panel can display color is because the light passes through the color filter. Then the liquid crystal panel is changed by driving the voltage of the chip, so that the liquid crystal molecules stand in a row or appear in a twisted state, forming a gate, and then selecting whether the light of the backlight penetrates or not, and finally produces a picture. But this is only a difference in the degree of light transmission, and the colors produced are only black and white. If you want to form a colorful picture, you need to rely on the combination of red, green, and blue light sources.

3. Alignment Layer

Alignment Layer is the most critical material to control the LCD display quality. In order to achieve a good rotation effect of the liquid crystal material, it is necessary to coat a layer of alignment film on the inner side of the upper and lower electrode substrates of the LCD display. After coating the alignment film, the rubbing process will be carried out. The surface of the alignment film will form a groove arranged in a certain direction due to friction, and the liquid crystal material on the alignment film will also be due to the interaction between molecules. Force to achieve a directional effect, resulting in alignment (Align) effect. In this way, we can control the predetermined direction and predetermined tilt angle arrangement of the liquid crystal molecules, which is very beneficial to the movement of the LCD display.

4. Liquid Crystal Material

The liquid crystal material is the main material of the LCD display. The liquid crystal materials selected for different devices are different, and most of the liquid crystal materials are mixed from several or even more than a dozen monomer liquid crystal materials. Each liquid crystal material has its own fixed clearing point TL and crystallization point TS. Therefore, it is necessary to require each LCD display to be used or stored within a certain temperature range between TS and TL. If the temperature of use or storage is too low, the crystallization will destroy the alignment layer of the LCD display; and If the temperature is too high, the liquid crystal will lose its liquid crystal state, and all the functions of the LCD display will be lost.

5. Polarizer

The main purpose of the polarizer is to make the light passing through the dichroic medium of the polarizing film produce polarization. The polarizer is made of plastic film material, coated with a layer of optical pressure-sensitive adhesive, which can be attached to the surface of the liquid crystal cell. So far, most of the most commonly used polarizers on LCD displays use polyvinyl alcohol (PVA) as the base material. There is also a protective film on the surface of the front polarizer, which should be removed when using it. The polarizer is very afraid of high temperature and high humidity, and it will depolarize or bubble under high temperature and high humidity conditions.

6. Drive Circuit

The biggest function of the driving circuit is to build on the driving circuit by adjusting a series of parameters such as voltage, phase, peak value, frequency, timing, effective value, and duty cycle applied to the pixel electrode.