Patent ID: 7452119

Claim:
A lighting device comprising: a first light source; a second light source driven independently from the first light source; and an optical waveguide including: side surfaces; a first corner that is truncated with respect to portions of the side surfaces connected to the first corner, the first corner having a planar surface that is non-parallel and non-perpendicular with respect to the portions of the side surfaces connected to the first corner, the first light source being disposed to face the planar surface of the first corner; a second corner that is truncated with respect to portions of the side surfaces connected to the second corner, the second corner having a planar surface that is non-parallel and non-perpendicular with respect to the portions of the side surfaces connected to the second corner, the second light source being disposed to face the planar surface of the second corner; a main plane from which light is emitted; a first set of grooves approximately concentric around the first light source, each groove of the first set of grooves having a first tripod pillar shape and including only a first inclined plane facing the first light source, the first inclined plane having only a first effective gradient angle reflecting light from the first light source at a first angle toward the main plane, each first inclined plane of each groove of the first set of grooves having the same first effective gradient angle, the lighting device having a first viewing angle corresponding to the first effective gradient angle when the first light source is driven; and a second set of grooves approximately concentric around the second light source, each groove of the second set of grooves having a second tripod pillar shape and including only a second inclined plane facing the second light source, the second inclined plane having only a second effective gradient angle that is different from the first effective gradient angle, the second effective gradient angle reflecting light from the second light source toward the main plane at a second angle different from the first angle, each second inclined plane of each groove of the second set of grooves having the same second effective gradient angle, the lighting device having a second viewing angle corresponding to the second effective gradient angle when the second light source is driven, the second viewing angle being narrower than the first viewing angle.