US Patent 7537373 Light guide plate and backlight module using the same

A light guide plate (30) includes a light incident surface (31), a light emitting surface (32) and a bottom surface (33). The light emitting surface adjoins the light incident surface. The bottom surface faces an opposite direction of the light emitting surface. A number of first microstructure units (321) and second microstructure units (323) are interlaced and formed on the light emitting surface. Each first microstructure unit has a number of first prism lenses (3211) extending out from the light emitting surface parallel to the light incident surface, and each second microstructure unit has a number of second prism lenses (3231) extending out from the light emitting surface perpendicular to the light incident surface.