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Origin of LCD light guide plates
Release time：2021-08-08
The core of LCD light guide plate lighting technology is the total internal reflection of light in PMMA. When light passes between two transparent media, reflection and refraction occur. When light travels from a medium with higher refractive index into air at an angle greater than the critical angle, total internal reflection occurs at the interface with no light escaping. Transmission loss only comes from material absorption, unlike metal reflection which loses 10%–15%. This is the principle of PMMA light guide plates.
The light guide plate was first invented by Japan’s Mito in 1986 as EDGE LIGHT, now the mainstream backlight for laptop LCDs. It uses a PMMA light guide plate to conduct and spread light from CCFL tubes. Light reflects off printed dots and emits vertically. This design achieves high brightness, small size, high efficiency and low power consumption, widely used in laptops, digital cameras and other large‑area LCD products.