Patent ID: 9239420
Filing Date: 2016-01-19
CPC Classification: G02B

Claim Text:
1. A light guide plate configured to allow light to enter through a light entrance surface, and allow the light to exit through a light exit surface while guiding the light in a light guide direction, comprising: a light entrance surface through which light enters; a light exit surface extending in a direction intersecting the light entrance surface and through which light exits; and a back surface that opposes the light exit surface, wherein a plurality of back surface-side unit optical structures are arranged in the back surface along the light guide direction, wherein each back surface-side unit optical structure is tapered in a direction away from the light exit surface, and has a first inclined surface lying on the light entrance surface side, a second inclined surface lying opposite the first inclined surface and which totally reflects at least part of incident light, and a top surface region lying between the first inclined surface and the second inclined surface, and located farthest from the light exit surface, and wherein in at least part of the back surface-side unit optical structures, the top surface regions each include a plurality of surfaces which are parallel to the light exit surface and have different heights in the direction away from the light exit surface, wherein the plurality of surfaces of each top surface region are arranged in the arrangement direction of the back surface-side unit optical structures, and wherein the surface, located closest to the first inclined surface, has the smallest height in the direction away from the light exit surface, and the height of each surface increases with distance of the surface from the first inclined surface.