LCD TV backlight module structure
Nov 29, 2021
1. Introduction to Backlight Module
Back light module is one of the key components of LCD panel. Since the liquid crystal itself does not emit light, the function of the backlight module is to supply sufficient brightness and uniformly distributed light sources to make it normal Display images. LCD panels are now widely used in electronic products with growth potential such as monitors, notebook computers, digital cameras, and projectors. As a result, the demand for backlight modules and related components continues to grow, stimulated by lower panel prices. , And the largest demand for large-size panels such as notebook computers and LCD monitors is the main source of driving force for the growth of demand for backlight modules. It is also the second key component of LCD panels.
Backlight module is the second key component of LCD panel
2. Backlight module category:
Generally speaking, the backlight module can be divided into two types: front light and back light. The backlight module can be classified according to the requirements of its scale and the position of the lamp, and the following three types have been developed. structure:
(1) Edge lighting structure: The light source is a single light source placed on the side, and the light guide plate is designed for injection molding without printing. It is generally used for small and medium-sized backlight modules below 18 inches. The incident light source design has the characteristics of light weight, thinness, narrow frame and low power consumption. It is also the light source for mobile phones, personal digital assistants (PDA), and notebook computers. At present, there are also large-size backlight modules that adopt edge-light type. structure.
(2) Bottom lighting structure: the ultra-large backlight module, the side-light structure has no advantages in weight, power consumption and brightness, so it does not contain a light guide plate and the light source is placed directly below the direct type structure Was developed. The light source consists of spontaneous light sources (such as lamps, light-emitting diodes)
Etc.) After being reflected by the reflector, it is emitted on the front surface after being evenly dispersed upwards through the diffuser. As the installation space becomes larger, the lamp can be used with up to 2 lamps depending on the size of the TFT panel, but at the same time, the thickness of the module is increased. , Weight, power consumption, and its advantages are high brightness, good light viewing angle, high light utilization efficiency, simple structure, etc., so it is suitable for LCD monitors and LCD TVs that have less demanding portability and space requirements. Problems such as high power consumption (using cold cathode tubes), poor uniformity and causing LCD heating still need to be improved.
(3) Hollow structure: As the size of images required increases, LCDs are also developing in the direction of larger sizes. Now such ultra-large LCDs are used as monitors and wall-mounted TVs, which not only require large screens , High brightness and light weight, electrical appliances also require low thermal effect under high power. In recent years, the hollow structure backlight module developed uses hot cathode tubes as the light source. This structure uses air as the light source transmission medium. After the light source is adjusted and reflected downward by the direction of the prism sheet and the reflecting plate, one part passes through the light guide plate upward and exits the surface, and the other part enters the hollow cavity again due to total reflection until it undergoes reflection. After acting, it exits through the light guide plate, and the upward light source either directly enters the light guide plate and exits, or exits after a series of philosophical reflections: the shape of the light guide plate is a wedge-shaped structure, and the purpose is to achieve a uniform effect.
Introduction to the key optical components of the backlight module:
The backlight module mainly provides a uniform and high-brightness light source for the liquid crystal panel. The basic principle is to transform a common point or line light source into a high-brightness and uniform brightness surface light source product through a simple and effective light mechanism. The general structure is to use the linear light source of the cold cathode tube to enter the light guide plate through the reflector, transform the linear light source into a uniform surface light source, and then use the light homogenization effect of the diffuser sheet and the light collection effect of the prism sheet to improve the brightness and uniformity of the light source. Evenness. Here we will introduce some basic components of the backlight module.
3. Backlight module composition: Light source, light guide plate, housing, reflector, diffuser, brightness enhancement film (BEF, prism film), black and white Glue (Curtain Tape) and so on. As the backlight requirements are getting thinner and thinner, some parts need to be added with a metal frame (METAL FRAME).
Glossary
Back light
Backlight is a form of lighting, often used for LCD displays. The difference between the backlight type and the front light type is that the backlight is illuminated from the side or the back, while the front light is illuminated from the front as the name implies. They are used to increase the illuminance in a low-light environment and the brightness of computer monitors and liquid crystal screens to generate light in a similar way to CRT displays. The backlight can be any color. Monochrome liquid crystals usually have backlights such as yellow, green, blue, and white. The color display uses white light because it covers the most shades.
Module
QTW module refers to the general name of devices that can realize linear motion in the field of automation industry, also known as positioning module. Linear modules can be considered as mechanical engineers through the transformation of machinery and the development of machinery, sharing experience and exchanging knowledge with each other, and finally come to a commonly used knowledge product.
light source
The light source refers to the self-brightness of the object itself. Some objects in the universe are luminous and some are non-luminous. We call the objects that can emit light by themselves and are luminous as the light source. The sun, electric lights, burning candles, etc. are all light sources.
