Hangzhou Xuhong Technology Co.,Ltd
EN
中文
The backlight of the TFT-LCD is mainly composed of light sources, optical membranes, and light guide plates.
1. light source
The light source used in the backlight determines the optoelectronics parameters such as energy consumption, brightness, and color of the backlight, and also determines the characteristics of their use conditions and service life. The light source is divided into three categories: linear light sources, dot -shaped light sources and facial light sources according to the luminous shape. The specific light sources and its characteristics are shown in the table. In TFT-LCD, CCFL wire-shaped light sources or LED dot-shaped light sources are mainly used.
Specific light sources and their characteristics
Light shape | Light source | Characteristics |
Linear light source | CCFL | High brightness&inverter driver voltage,long longevity, |
HCFL | overheat | |
Dot light source | LED | Long life,low heating,slightly low brightness |
Facial light source | VFD | Thin, uniformity, short life, low brightness |
ELD | Ultra -thin and flat, uniform brightness, long life, bendable | |
OELD | Thin, uniformity, high brightness, short life | |
FED | high brightness |
2. Optical membrane
Backlight sources should provide TFT-LCD with a high-brightness, high uniform facial light source for TFT-LCD. The optical film used in the backlight is mainly divided into two categories:
One is the diffusion film and reflex sheet. The main function is to strengthen the luminous uniformity of the surface light source; the other is the bright film, and the main function is to improve the light brightness of the backlight.
The diffusion film is divided into diffusion pieces and diffusion plates, and the diffuser is divided into two types: lower diffusion sheet and upper diffusion tablets. The basic composition of the diffuse film is the diffusion layer+substrate+protective layer. The diffusion board is placed above the straight backlit source. The purpose is to spread the light emitted by the light source to keep the uniformity of the brightness inside the surface, thereby preventing the shadow of CCFL or LED on the surface. Another function of the diffusion board is to support the various optical membranes above to prevent optical membrane drooping and affect the optical effect.
The brighter membrane includes BEF (Brightness Enhanced Film) and DBEF (DBEF (DOUBLE BRIGHTNES ENHANCED FILM). BEF gathers the divergent light within a smaller range through the principle of concentration to enhance the light within this range. DBEF uses reflection and reuse to improve the brightness of the light source as a whole.
3. Light guide plate
The light guide plate used in the side optical backlight can turn the linear light emitted by CCFL, LED and other light sources into a facial light with good luminous efficiency. From the light of the light guide plate, the brightness is large from the side perspective. By configured the optical membrane on the light guide plate, the brightness of the front perspective can be maximized.
AUO LCD:https://www.auo-lcd.com/products/auo-lcd-screen/
Innolux lcd:https://www.auo-lcd.com/products/innolux/
