Patent ID: 8042983

Claim:
A light guide plate comprising: opposite surfaces, a peripheral surface between the opposite surfaces; an incident plane formed at the peripheral surface and configured to receive light emitted from a light source; a plurality of prisms formed on one of the opposite surfaces, and each of the plurality of prisms having a reflection plane having a tilt angle that reflects the light entering the incident plane, and a back plane adjacent to the reflection plane, the plurality of prisms including at least one prism disposed adjacent to the incident plane; and wherein the reflection planes of the plurality of prisms are extended in a direction that crosses a traveling direction of the light that is emitted from the light source and traveling in the light guide plate, wherein the prism that is disposed adjacent the incident plane includes a valley line between the reflection plane and back plane of the prism disposed adjacent the incident plane, the valley line being part of an arc curving away from the incident plane decreasing the tilt angle along the valley line in a direction from the side of the light guide plate towards the center.