Light guide plate having high utilization of light energy and backlight module adopting the same

摘要

A light guide plate includes an incident surface, an emission surface, and a bottom surface. The emission surface intersects with the incident surface and is substantially perpendicular to the incident surface. The bottom surface intersects with the incident surface and is opposite to the emission surface. The light guide plate is birefringent and has internal stresses/strains therein, causing the light guide plate to exhibit a light-polarizing phase delay. An angle between a direction of one of the main stresses/strains and the light incident surface is bigger than 0 degree and smaller than 90 degrees. A plurality of sub-wavelength gratings can be further formed on the emission surface of the light guide plate. A backlight module, adopting the above-mentioned light guide plate, further includes a corresponding light source positioned beside the incident surface of the light guide plate.