Patent ID: 7973879

Claim:
A backlight unit for a liquid crystal display device, comprising: a reflection sheet; at least one lamp arranged over the reflection sheet; a diffuser plate over the at least one lamp, the diffuser plate including a base plate of a transparent material, a diffusion layer directly on and contacting a first surface of the base plate facing the at least one lamp, and a light concentrating layer directly on and contacting a second surface of the base plate opposite to the first surface; and optical sheets over the diffuser plate, the optical sheets including a reflective polarizing sheet, wherein the reflective polarizing sheet includes a reflective polarizing layer having a predetermined polarization axis and first and second diffusion layers, wherein the first diffusion layer is directly on and contacts an upper surface of the reflective polarizing layer, and the second diffusion layer is directly on and contacts a lower surface of the reflective polarizing layer opposite to the upper surface, wherein the lower surface of the reflective polarizing layer faces the diffuser plate, wherein the second diffusion layer has a haze value of 60% to 70% and the first diffusion layer has a haze value of 70% to 90%.