Patent ID: 7344291

Claim:
A backlight device including a light guide plate guiding the light rays incident thereon from a light incident surface thereof as said light rays undergo total reflection on a light radiating surface and a light reflecting surface as one and the other of the major surfaces of the light guide plate, said light guide surface radiating the light rays by in-plane light radiation from said light radiating surface, said backlight device comprising a plurality of illuminating devices provided at a preset interval on the light incident surface side of said light guide plate, said illuminating devices each including a first light source for radiating light rays of a first prime color; a second light source for radiating light rays of a second prime color and a third light source for radiating light rays of a third prime color, said first, second and third light sources being arrayed in the same plane; respective optical means for collimating divergent light rays, contained in said light rays of the first prime color, radiated from said first light source, said light rays of the second prime color, radiated from said second light source and in said light rays of the third prime color, radiated from said third light source; and color mixing means for color mixing said light rays of the first prime color, said light rays of the second prime color and said light rays of the third prime color, radiated from said optical means, by selective transmission and reflection, based on optical properties of the light rays of the respective prime colors, and for radiating the mixed light rays as white light.