Surface light source, method for manufacturing the same and apparatus using it

摘要

The light emitted from a spot light source ( 45 ) is emitted at a linearly extending region by a wedge-like light conductor ( 47 ) and deflected by a prism sheet ( 50 ). This light is emitted in a direction perpendicular to a light incident surface ( 44 a) of the light conductor plate ( 44 ) and has a directivity narrow in a widthwise direction of the light conductor plate ( 44 ). The light conductor plate ( 44 ) is formed, at its bottom surface, with a multiplicity of diffusion patterns ( 46 ) in a rectangular triangular form. The light reflected upon the diffusion pattern ( 46 ) is emitted perpendicularly to alight emitting surface ( 44 b) of the light conductor plate ( 44 ). At this time, part of the light incident on the diffusion pattern ( 46 ) transmits through the diffusion pattern ( 46 ) whereby the directivity of emission light is narrowed in a lengthwise direction of the light conductor plate.