LIGHT CONTROL PLATE, SURFACE LIGHT SOURCE DEVICE AND TRANSMISSIVE IMAGE DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a light control plate, a surface light source device and a transmissive image display device that allow parallel light having a uniform luminance distribution to be spread within a prescribed angle range and to be emitted as light having a substantially uniform luminance angular distribution within the angle range.

SOLUTION: A light control plate 30A is disposed in front of a surface light source 20 that emits, in a prescribed direction, parallel light Fihaving a substantially uniform luminance distribution. The light control plate 30A has a light incidence surface 30a, at which there are provided optical path control sections 31A of a concave and/or convex cross-sectional shape, and a planar light exit surface 30b. The surface of the optical path control sections 31A comprises M of planar portions 32A1to 32AM. The inclination angles α1to αMand pitch ratios L1to LMof the respective planar portions are specified in such a manner that the parallel light Fican be spread within an exit angle range from -θmax to θmax relative to the prescribed direction, to exit as light having a substantially uniform luminance angular distribution within the exit angle range.

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