Patent ID: 9360613
Filing Date: 2016-06-07
CPC Classification: G02B

Claim Text:
1. A planar light source apparatus comprising: a point light source; a housing having an opening portion; and a light guide plate arranged in said housing and having a flat plate shape, which flat plate shape is rectangular in a plan view, wherein said light guide plate includes an output surface confronting said opening portion, a non-output surface opposed to said output surface, a pair of first side surfaces opposed to each other, a pair of second side surfaces opposed to each other, and a hole opening in said non-output surface, wherein said hole is located closer to one of said first side surfaces where said point light source is to be arranged than to either of said second side surfaces, each of said pair of second side surfaces is at least partially configured as a prism in form, whose ridge line extends in a direction perpendicular to said output surface and whose cross-section, when sectioned in a direction parallel to said output surface, has a sawtooth shape in which concavity and convexity are repeated, wherein in said prism, an angle from a valley of said sawtooth shape to a peak of said sawtooth that is adjacent to said valley and located at a side farther from said point light source is defined as a first angle, and an angle from a valley of said sawtooth to a peak of said sawtooth that is adjacent to said valley and located at a side closer to said point light source is defined as a second angle, wherein said first angle and said second angle of said prism are arranged such that incident light from said point light source and guided by said light guide plate is reflected and refracted from said prism back into said light guide plate, and wherein said first angle and said second angle of said prism are arranged such that the reflected and refracted light propagates in a direction away from the one of said first side surfaces and said point light source, and such that incident light from said point light source is reflected and refracted from said prism such that an angle of the reflected and refracted light, relative to a direction parallel to said first side surfaces, is greater than an angle of the incident light.