Patent ID: 7819568

Claim:
A planar lighting device comprising: a light guide plate including: a light exit plane; a pair of first light entrance planes formed respectively adjacent a pair of sides of said light exit plane; a pair of second light entrance planes formed respectively adjacent the other pair of sides of said light exit plane; and a pair of rear planes formed opposite to said light exit plane and inclined such that a thickness of said light guide plate in a direction perpendicular to said light exit plane increases with an increasing distance from said pair of first light entrance planes, respectively, toward a central part of said light exit plane; a pair of main light sources disposed opposite said pair of first light entrance planes of said light guide plate, respectively, and emitting light to said pair of first light entrance planes, respectively; a pair of auxiliary light sources disposed opposite said pair of second light entrance planes of said light guide plate, respectively, and emitting light to said pair of second light entrance planes; and illuminance distribution control means for adjusting amount of light emitted respectively by said main light sources and said auxiliary light sources to form a designated local illuminance distribution for any position in said light exit plane of said light guide plate, wherein said main light sources and said auxiliary light sources each comprising light sources and a base on which said light sources are arrayed in a longitudinal direction of said pair of first light entrance planes and said pair of second light entrance planes, respectively.