To provide an optical sheet which improves the brightness and reduces the color separation on the front surface.
The optical sheet 1 is used in the edge lighting back light device. On the main surface 10 of the optical sheet 1, a number of pillar-shaped lenses 20 are formed in parallel. Each pillar-shaped lens has a main ridge 30, a sub-ridge 40, and a plurarity of grooves GR arranged in the longitudinal direction. The two slopes forming the sub-ridge refract the emission light from the light guide plate in the directions opposite each other to cancel the color separation. Further, the main ridge 30 and the sub ridge 40 converge the light running in the crossing direction of the pillar-shaped lens 20 (in the X direction). Also, the grooves GR converge the light running in the longitudinal direction of the pillar-shaped lens 20 (the Y direction). Thus, the optical sheet 1 improves the brightness on the front surface by converging the light running in two directions.
COPYRIGHT: (C)2010,JPO&INPIT
SATO NOBUTAKA
ISHIHARA NOBUYASU
Tadashi Takezoe
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