The TFT-LCD panel is mainly composed of the following parts:
LCD panel
TFT panel
Backlight module
Backlight source (or backlight module)
The backlight layer is mainly composed of a backlight source and a light guide plate, usually using LED light sources. Liquid crystal molecules themselves do not emit light, so a backlight is needed to provide light, which is then deflected by the liquid crystal molecules to produce different colors. The function of a backlight is to provide light energy. After the lamp tube emits light, the light is distributed to various places through the light guide plate, and then the direction of all the light is concentrated towards the liquid crystal molecules through the reflection plate. Finally, the light is evenly emitted through a diffuser (or light guide plate) to avoid situations where the central brightness is too high and the surrounding brightness is too low.
Diffusion sheet
In the backlight structure, the diffuser mainly plays a role in correcting the diffusion angle, increasing the radiation area of light, but reducing the light intensity per unit area, that is, lowering the brightness. After being diffused by a diffusion material, the luminous light source has a larger area and better uniformity.
Brightening film
Brightening film, also known as prism film, usually has two layers on top and bottom, mainly used for brightening. It is placed between the diffuser of the backlight and the liquid crystal panel, and converges the uniformly diverging light emitted from the diffuser to the axial angle, that is, the front view angle, thereby improving the axial brightness. If the diffusion sheet or prism film is locally damaged, the exported light will have problems, resulting in white spots and other issues appearing on the screen.
Polarizing film
The function of polarizing film is to allow light to pass through in one direction. It is made by dyeing and stretching PVA film, which determines the polarizing performance and transmittance of polarizing film, and also affects the color tone and optical durability of polarizing film.
Glass substrate
A glass substrate is not just two pieces of glass, it has a groove structure on the inside and is attached with an alignment film, which allows liquid crystal molecules to be arranged neatly along the grooves. TFT thin film transistors and color filters will be affixed on both sides of the upper and lower glass layers. The liquid crystal layer is sandwiched between two layers of glass.
Thin film transistor (TFT)
The TFT thin film transistor in TFT-LCD is a key component for controlling signal voltage, similar to a switch. It can control the signal voltage on the IC control circuit and deliver it to the liquid crystal molecules, determining the angle of deflection of the liquid crystal molecules.
Liquid crystal molecular layer
The liquid crystal molecular layer is the most important element that changes the polarization state of light, and its arrangement and polarization state are determined by both electric and elastic forces.
Through the joint action of these parts, TFT-LCD panels can display rich and colorful images. I hope this article can help you better understand the structure and working principle of TFT-LCD panels!