| 摘要 |
PURPOSE: A backlight unit is provided to increase a recycle ratio of a side exit light at up and down, and right and left viewing angles by differentiating refraction and total reflection conditions of light exited from a prism sheet, and increase the brightness. CONSTITUTION: A light guide plate has a plurality of engraved patterns having predetermined depths at predetermined gaps. A diffusion sheet diffuses an optical beam passing through the light guide plate. A prism sheet controls a proceeding direction of the optical beam passing through the diffusion sheet. A vertical angle of the prism sheet toward a display panel is more than 90 deg. and less than 140 deg. |
