LCD light guide plate manufacturer: The origin of LCD light guide plate
Release time:2025-09-29
The key to LCD light guide panel lighting technology is the total reflection effect of light in PMMA. We know that light undergoes reflection and refraction when passing through two transparent media. When light is emitted from a transparent medium with a refractive index greater than air to air, due to the difference in refractive index, when the incident angle θ is greater than a certain angle, it will undergo total reflection at the interface and no longer emit light from the medium. In other words, the transmission loss of light inside the medium depends only on the absorption of light by the medium, and there is no loss when reflected at the interface (light usually loses 10% to 15% when reflected on a metal surface). PMMA light guide panel utilizes this characteristic.
The LCD light guide plate lighting technology was first invented by Japan's Mingtuo Company in 1986, called EDGE LIGHT. It is currently the mainstream method for backlighting LCD displays in laptops, and its working principle is to use PMMA The transparent light guide plate will emit pure white light from the cold cathode fluorescent tube (line light source), which is introduced and diffused from the end face of the transparent plate to the entire surface. When the light shines on the white reflective dots printed on the back of the light guide plate, diffuse reflection occurs, and it is emitted from the surface (working surface) perpendicular to the light source incident surface. The illumination of the light guide plate cleverly uses the principle of total reflection of light at the interface of the transparent plate, deflects the light incident on the end face by 90 °, and emits it from the front, thus playing the role of illumination. This illumination method has high surface brightness and compact lighting system volume, high light utilization efficiency, and low power consumption. It has been widely used in products such as laptops and digital cameras that require large-area LCDs.
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