Patent ID: 7530720
Filing Date: 2009-05-12
Classification: G02B

Abstract:
1. A backlight unit comprising: a planar light source member having a light-emitting surface, the planar light source member being configured to emit from the light-emitting surface light having a single directivity perpendicular to the light-emitting surface; and an optical member having a light-receiving surface facing the light-emitting surface of the planar light source member and a light-emitting surface opposite to the light-receiving surface, the light-receiving surface and light-emitting surface of the optical member being parallel to the light-emitting surface of the planar light source member, the light-receiving surface of the optical member having a multiplicity of prisms extending parallel to each other and perpendicular to the directivity direction of the light from the planar light source, so that the light from the planar light source having the single directivity and incident perpendicularly upon the light-receiving surface of the optical member is transformed by the prisms into light having at least two different directivities and emitted from the light-emitting surface of the optical member in directivity directions each angled around a perpendicular to the light-emitting surface of the optical member.