PLANE LIGHT SOURCE

PROBLEM TO BE SOLVED: To provide a plane light source to be used for a liquid crystal display device or the like in which leaked light or partially bright portion do not occur even if a device is miniaturized and a panel brightness does not become uneven. SOLUTION: The plane light source is provided with a light source 2 and a light guide plate 3 which is of a mostly plane shape in an entire view and in which light incident form a side of a base end surface 3a is reflected at a rear surface 3d and/or a far end surface 3b and is discharged from a light emitting surface 3c. A light collecting structure 4 having a light collecting function is provided near the base end surface 3a, or there is provided a light collecting structure 4 in which a mirror structure 5 is arranged near the base end surface 3a and which has a light collecting function near an end edge of a side of the base end surface of the light emitting surface 3c or a rear surface 3d, and an angle of a corner made by the light emitting surface 3c of the light guide plate 3 and the base end surface 3a is within a specific range, and the light source 2 is arranged above or below the base end surface 3a. COPYRIGHT: (C)2009,JPO&INPIT