Back light module and light guide plate thereof

Abstract

A light guide plate adapted to a backlight module is provided. The backlight module has a plurality of point light sources providing a light beam of a predetermined wavelength. The light guide plate includes a light emitting surface, a bottom opposite to the light emitting surface, a light incident surface connecting the light emitting surface and the bottom, a plurality of grating structures, and a plurality of diffusion dots. The light incident surface is near the point light sources. The diffusion dots are disposed on the bottom. At least portions of the grating structures are disposed on the light incident surface. Each of the grating structures has a plurality of concave parts and a plurality of protruding parts. Each of the concave parts is disposed between two neighboring protruding parts. A ratio of the predetermined wavelength to a pitch between two neighboring protruding parts is ranged between 1.2 to 1.3.

Dependencies are inferred from the claim text.