The part of a TFT LCD that produces the white light required to illuminate the screen is called the backlight unit. A light guide plate, a diffuser sheet, and a reflector are some of the layers that make up the backlight unit, which is situated behind the TFT array.
The light guide plate, the major component of the backlight unit, is in charge of distributing light uniformly across the screen. The translucent plastic light guide plate’s surface has optical patterns that aid in distributing the light evenly.
How it works:
The white light required to illuminate the screen is produced by the backlight unit using one or more cold cathode fluorescent lamps (CCFLs) or light-emitting diodes (LEDs). The light produced by the LEDs or CCFLs passes through the light guide plate, illuminating the screen uniformly.
In order to further diffuse the light and lessen the appearance of hotspots and bright spots on the screen, the diffuser sheet is placed on top of the light guide plate. The back of the backlight unit has a reflector that directs any stray light back towards the light guide plate to increase the effectiveness of the backlight unit.
Types of backlight units:
There are two main types of backlight units used in TFT LCD manufacturing:
- CCFL backlight units: These backlight units generate the white light required to illuminate the screen using one or more CCFLs. Although they are less expensive to produce than LED backlight units, CCFL backlight units are less energy-efficient.
- LED backlight units: These backlight units generate the white light required to illuminate the screen using an array of LEDs. Although they are more expensive to produce, LED backlight units are more energy-efficient than CCFL backlight units and offer better colour accuracy.
In conclusion, a TFT LCD’s backlight unit, which produces the white light required to illuminate the screen, is an essential part of the device. The light is generated by one or more CCFLs or LEDs in the backlight unit and is distributed evenly across the screen by way of a series of layers, including a light guide plate, diffuser sheet, and reflector. Depending on the particular needs of the application, various backlight unit types are used in TFT LCD manufacturing.
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