Application Of Backlight Module in Liquid Crystal Display

In general product applications, in order to reduce costs and improve efficiency, the backlight source and its driving circuit, optical films for improving optical performance, and other ancillary components are usually integrated into a component that can be used directly with the liquid crystal panel, that is, a backlight module. The backlight module is an important component that constitutes a liquid crystal display, and it is also an important component that affects the display quality and performance of the liquid crystal display.

There are three main types of backlight sources for backlight modules: Cold Cathode Fluorescent Lamps (CCFL), Electroluminescence (EL), and Light Emitting Diode (LED). Before 2008, CCFL was the mainstream light source for backlight modules. CCFL had the advantages of high brightness, long service life and low cost. However, CCFL also has shortcomings such as low color gamut coverage, poor color reproducibility, and high power consumption. Moreover, CCFL itself contains mercury, which is not conducive to environmental protection, thus restricting the further development of LCD to a certain extent. After 2008, with the maturity of white light LED technology, LED backlight source with high light efficiency, high color rendering ability, long life, wide color gamut, lead-free and mercury-free, low voltage drive, high response speed, similar point light source, The advantages of being compact and unbreakable have begun to emerge, and have become the preferred technical solution for the next generation of green display technology.

According to the different setting positions of the backlight source in the module, the LED backlight module can be divided into two types: direct-type (Direct-Type) and edge-type (Edge-Type). In the edge-lit backlight module, a plurality of LED light sources are arranged on the side of the module, and a uniform light-emitting surface is formed through a light guide plate, a reflective film, and a diffuser film. In the direct type LED backlight module, the LED array is evenly distributed under the LCD display panel, and the combined effect of the reflective cavity and the diffusion film, etc., can obtain a flat luminous effect with uniform brightness.

Compared with the two technologies, the edge-lit type can save more LED particles, and since the LEDs in the edge-lit scheme are arranged on the side, the overall thickness of the LCD can be very thin, but the edge-lit structure is not very suitable for super-sized LEDs. Backlight module, and it is difficult to implement block brightness adjustment in the edge-lit solution, resulting in the sacrifice of the contrast and color saturation of the picture; while the direct-lit LED backlight module does not need to use a light guide plate, and is directly uniformly arranged at the bottom of the module. The LED light source of the LED is free to mix light in a certain space, and then exits to the surface of the module, which can well solve the shortcomings of the edge-type LED backlight module in the large size.