Patent ID: 7690831
Filing Date: 2010-04-06
Classification: F21Y,G02B

Abstract:
1. A surface light source device comprising: two or more point light sources that are arranged linearly; a light guide plate having a side surface which is an incident surface on which light emitted from each of the point light sources shines, for outputting input light from a front surface thereof; and light diffusing means provided on a back surface of the light guide plate, for diffusing light, wherein the incident surface of the light guide plate includes a front side portion closer to the front surface than the back surface, a back side portion closer to the back surface than the front surface, and an inclination angle relative to a plane perpendicular to the front surface, wherein the back side portion of the inclined incident surface of the light guide plate is further from the point light sources than the front side portion of the inclined incident surface, wherein the inclination angle of the back side portion of the incident surface of the light guide plate is larger than the inclination angle of the front-side portion of the incident surface, and wherein the incident surface of the light guide plate includes two or more planes having different inclination angles that increase as the position goes away from the front surface of the light guide plate.