TFT LCD screen Light Guide Plate (LGP) is a material that works based on the principles of light reflection and light scattering. This article mainly introduces the installation of TFT LCD screen: including manufacturing method, installation structure, effective light-emitting installation area and gap, position fixation, warpage control, etc.
1. Manufacturing method.
Light guide plates are usually formed by injection and cutting. Injection molding uses an injection molding process to inject plastic particles into light guides that are smooth on one side and optical spots on the other, such as ultra-thin light guides and small light guides. Cutting and making a light guide plate is to use a large light guide plate to cut a light guide plate of the desired shape, and then use a material with high reflectivity and no light absorption on one side of the cut light guide plate, and use a screen printing process on the bottom surface of the light guide plate. Print round or square dots to spread the light. When the light hits the dot, the light will be reflected in all directions, then break the reflection conditions and be emitted from the front of the light guide. In order to ensure that the reflection probability of light in all directions is approximately the same, and to make the light-emitting surface of the light guide plate emit light uniformly, it is necessary to use various densities and different sizes of dots. As a complement, a reflective film is also arranged under the light guide plate to reflect the light leaking from the bottom back to the light guide plate, so as to improve the utilization rate of light and increase the brightness.
2. Installation structure.
The assembly structure of the light guide plate can be divided into reverse assembly and forward assembly. The reverse installation is to design a fitting structure on the plastic frame and the light guide plate, so that the light guide plate and the plastic frame form a whole. The light utilization rate of the reverse-mounted light guide plate is low, and it is generally limited to small-sized products. Formal assembly is assembled one by one from the back panel. It's easy to assemble. Mainly used for large and medium-sized products. Formal structures are easy to disassemble and rework all parts, but have the disadvantage of increasing the assembly process. Although the cost is increased due to the increase of the formal installation process, this structure is very helpful to improve the light utilization rate of the light guide plate.
3. Effective lighting installation area and clearance.
In the viewing angle specification, the corresponding display screen needs to be illuminated with light, so the design of the light guide plate needs to fully consider the effective light emitting area. The material of the light guide plate will expand or contract with changes in ambient humidity or temperature, so the design of the gap between the light guide plate and the adjacent components should not only consider the tolerance, but also consider the expansion and contraction. If the light guide plate interferes with the connected structure, noise will be generated when it vibrates. Pay special attention to the design of the gap between the light guide plate and the rubber frame.
4. Fixed position.
The fixed position of the light guide plate is designed to prevent the light guide plate from loosening in the gap after being subjected to external force. The position is fixed by bump fit. The convex part is designed on the light guide plate, and the concave part is designed on the rubber frame. The convex part of the light guide plate needs to ensure that there is no stress concentration problem after being impacted by external force.
5. Warpage control. Warpage is the main defect of the light guide plate. After a reliability test at high temperature and high humidity, swelling and warpage occur due to high water absorption. When the light guide plate is warped, it will wrinkle the adjacent aperture or interfere with the display screen, resulting in abnormal display. As a countermeasure, the allowable warpage of the light guide plate should be specified in the design of the light guide plate. When making the light guide plate, the molding conditions should be adjusted, and the gap between the light guide plate and the rubber frame should be appropriately increased in the structural design.
This is the correct TFT LCD screen. Briefly how to install the light guide plate.
How is the light guide plate of the TFT LCD screen installed?
2022 06/02