Patent ID: 9256203
Filing Date: 2016-02-09
CPC Classification: F21V,G02B,G03H

Claim Text:
1. A surface light source device comprising: a light source; a beam splitter configured to split a light irradiated from the light source into a plurality of light beams each having a different path; a diffusion unit configured to diffuse the plurality of light beams split by the beam splitter into a surface light; a collimating unit configured to arrange the plurality of light beams diffused from the diffusion unit in one direction; and an optical mask configured to change a beam intensity distribution of a beam collimated by the collimating unit, at a cross-section of the beam, wherein the optical mask has a non-uniform light transmittance distribution, and the light transmittance distribution is determined so that a relatively low light transmittance occurs in an area that corresponds to an area where beam intensity is relatively high in comparison to other areas.