How to select backlight source

The backlight source is mainly composed of light source, light guide plate, optical module and structural parts.

1. Selection of light source

Electroluminescence (EL) backlight is light and thin, providing uniform light. It has a very low power consumption and requires a working voltage of 80-100VAC. The inverter providing the working voltage can transform the 5/12/24Vdc input into ac output. However, the service time of EL backlight is limited, so an ideal inverter for EL backlighting allows the output voltage and frequency to increase with the aging of EL bulbs, thus extending the effective service time of displays using EL backlight sources.

2. Selection of light guide plate

The role of the light guide is to guide the direction of light scattering, used to enhance the Brightness of the panel, and ensure the uniformity of the panel brightness. The quality of the light guide plate has a great influence on the back light plate. Therefore, the design and manufacture of the light guide plate in the side light back plate is one of the key technologies. Is the method of using injection molding of light guide plate out smooth surface of the acrylic plate, and then use high reflection and not material suction light, in the bottom, use of the guide plate diffusion point on the way of printing, screen printing CCFL or LED light bar is located at the side of light guide plate, the light emitted by using the reflection import guide plate inside, when the light beam to spread, the reflected light will spread to different perspectives, and then will damage reflection conditions by positive injection of light guide plate. Diffuser points of different density and different size can be used to make the light guide plate shine uniformly. The purpose of the reflector is to reflect the light exposed from the bottom back to the light guide plate to improve the efficiency of the use of light. The light guide plate can be divided into printing and non-printing (injection molding) according to the different process flow. The printing type is the material with high reflectivity and no light absorption on the acrylic plate, and the circular or square diffusion points are printed on the bottom surface of the light guide plate with screen printing. The non-printing type USES a fine mold to make the light guide plate in the injection molding, adding a small amount of granular material with different refractive index into the propylene material, directly forming dense tiny bumps, which act like dots. The printing method is not as effective as the non-printing method. The non-printing method has excellent effect, small number of users, fast speed and high efficiency, but the technical threshold is very high, which requires mastery of fine injection molding, fine mold, optics and other technologies.

3. Selection of optical diaphragm

Under certain light source output, the frontal brightness, or axial brightness, of the liquid crystal module will be enhanced by prism film, reflective polarizer and high reflectivity reflector. Without increasing the number of light sources, there are two ways to improve the axial brightness: first, improve the angular distribution of the light and focus the light on the facing Angle; Second, reduce the loss and increase the total luminous flux.