Patent ID: 8164711

Claim:
A liquid crystal display device comprising: a liquid crystal display panel; and a backlight which radiates lights to the liquid crystal display panel, wherein the backlight includes a light guide plate and a light source arranged on an outer peripheral portion of the light guide plate, and a light diffusion sheet which is arranged between the light guide plate and the liquid crystal display panel, the light guide plate is made of a transparent plastic resin having a refractive index of 1.53 or less, the light guide plate has a first main surface and a second main surface which faces the first main surface in an opposed manner, the first main surface of the light guide plate is disposed at a position which is closer to the liquid crystal display panel than a position of the second main surface of the light guide plate with respect to the liquid crystal panel, the second main surface has a plurality of first inclined surfaces, and a polarization direction of the lights radiated from the light guide plate and a polarization direction of the light diffusion sheet are set equal to each other.