Patent ID: 7597469

Claim:
A backlight unit comprising: at least one point-shaped light source unit having point-shaped light sources arranged in a single direction in a predetermined order, the light sources emitting monochromatic light of different colors; a first light guide plate, which has a light incident surface and a light exiting surface, for receiving monochrome light emitted from respective light sources of the light source unit at the light incident surface and guiding said light to the light exiting surface; a reflector for reflecting the light exiting from the light exiting surface of the first light guide plate; a second light guide plate, which has a light incident surface and a light exiting surface, for receiving the light reflected by the reflector at the light incident surface of the second light guide plate and guiding said light to the light exiting surface of the second light guide plate; a diffusing plate for receiving the light exiting from the light exiting surface of the second light guide plate, diffusing said light, and emitting said light diffused; a first optical filter for limiting or controlling transmission of the monochromatic light emitted from one of the light sources disposed at one end of the light source unit; and a second optical filter for limiting or controlling transmission of the monochromatic light emitted from another of the light sources disposed at the other end of the light source unit, wherein the first optical filter and the second optical filter are selectively formed on one of the first light guide plate, the second light guide plate, and the diffusing plate, and wherein a base of said point-shaped light source unit is parallel to said light incident surface of the first light guide plate.