Patent ID: 8704973

Claim:
An optical sheet disposed above a light guide plate, the optical sheet comprising: a first layer having a larger refractivity than air; a second layer having a larger refractivity than the first layer; a refractive pattern disposed at a boundary surface between the first layer and the second layer, the refractive pattern having one or more ridges that change a traveling path of light; a third layer having a lower refractivity than the first layer; and a diffusion layer that diffuses light on the second layer, wherein the third layer is disposed at the lower surface of the first layer and facing the light guide plate, wherein the upper surface and the lower surface of the third layer is formed in a plate shape, wherein the optical sheet is operable to refract light from the light guide at least three times in a direction of the upper area of the optical sheet to a light-exiting surface, wherein the diffusion layer includes a plurality of beads, wherein the optical sheet includes the first, second and third layers for condensing light and the diffusion layer for diffusing light, wherein a boundary surface between the first layer and the third layer is not formed as a refractive pattern, and wherein the lower surface of the third layer is not formed as a refractive pattern.