Light guide plates and light guide plate assembly utilizing diffraction grating

摘要

A light guide plate is provided which utilizes the phenomenon of diffraction based on wave optics of light, and which can provide much higher and more uniform brightness over an entire illuminated surface than the brightness level achievable by the prior art and can assure longer battery life through reduced power consumption for a light source. The light guide plate consists of a transparent plate, at least on one end of which light rays from the light source fall. The light guide plate has a diffraction grating printed or worked on a bottom surface thereof such that at least one of a grating part width/non-grating part width ratio in unit-width or a sectional configuration of the diffraction grating is varied so as to enhance and uniform light intensity on a top surface of the light guide plate.