Patent ID: 8821001

Claim:
A light source device comprising: a light guide plate having a first internal reflection plane and a second internal reflection plane which face each other; one or more light sources each applying illumination light through a side surface of the light guide plate into an interior thereof; and an optical device disposed to face the light guide plate, and modulating, for each of partial regions thereof, a state of light rays exiting therefrom, wherein one or both of the first internal reflection plane and the second internal reflection plane each have scattering regions each allowing the illumination light from the light sources to be scattered and exit from the first internal reflection plane of the light guide plate, and one or both of the first and second internal reflection planes, which are planes having the scattering regions, each have total-reflection regions allowing the illumination light from the light sources to be reflected in a manner of total-internal-reflection, and the optical device is disposed to face a surface corresponding to the second internal reflection plane of the light guide plate, and is allowed to switch, for each of partial regions thereof, a function performed on incident light rays between a scattering-reflection mode and a light absorption mode.