Views: 0 Author: Site Editor Publish Time: 2021-12-03 Origin: Site
The liquid crystal display is a passive light-emitting element. The display itself does not emit light, but is illuminated by the backlight system below it. The backlight source and the liquid crystal display are combined to form a liquid crystal display module. The liquid crystal backlight is a flat, uniform lighting device. Cold cathode fluorescent tubes or LED strips as the light source are arranged on both sides or one side of the entire backlight. The cold cathode tube is a linear light source, and the LED is a point light source. The light guide plate is needed to convert this light source into a surface light source. The light guide plate is generally made of acrylic plastic with high light transmittance, and the surface is very smooth and flat, so that most of the internal light will be regularly and totally reflected on the flat surface, and will not be emitted to the outside of the light guide plate.
l What is the role of the light guide plate?
l What is the working principle of the LCD backlight?
l What are the classifications of light guide plates?
The bottom of the light guide plate of the liquid crystal display is printed with white dots. At the position where the light guide plate is printed with dots, the light will no longer be totally reflected regularly but will be emitted from the top of the light guide plate. Controlling the density of dots at each position can control how much light the light guide plate emits at this position. Precisely designed light guide plate dots can spread the incident light on both sides evenly on the entire plane. Optical films will be placed above the light guide plate. These films can uniform light and converge large-angle light for frontal observation.
The light source, the light guide plate, the reflective sheet, and the optical film constitute the backlight source of the liquid crystal display. When the light emitted by it is irradiated on the liquid crystal panel, the light will first pass through the lower polarizer and pass through upwards. At this time, different liquid crystal panels will change the polarization direction of the light according to their own mechanism. The light then touches the color filter to produce color, and finally enters the upper polarizer. After the polarization direction is changed by the liquid crystal, part of the light can be emitted, and part of it will be absorbed. Each pixel on the entire LCD panel can individually determine the intensity of the emitted light. Resulting in an image.
The light guide plate can be divided into printing type and non-printing type (injection molding type) according to the different process flow.
The printing type is to use a high-reflectivity and non-light-absorbing material on the acrylic plate, and use a screen printing to print a circular or square diffusion point on the bottom of the light guide plate.
The non-printing type uses a precision mold to add a small amount of granular materials with different refractive indexes to the acrylic material when the light guide plate is injection molded to directly form densely distributed tiny bumps.
The printing method is not as effective as the non-printing method. The non-printing method has excellent effects, a small number of users, fast speed, and high efficiency, but the technical threshold is high. It is necessary to master precision injection molding, precision molds, optics and other technologies. At present, most domestic manufacturers still use printed light guide plates as light guide components. Printed light guide plates have the advantages of low development cost and fast production, while non-printed light guide plates are more technically difficult, but have excellent brightness.
In addition, the products we provide include Acrylic sheets and so on.