Patent ID: 7452118
Filing Date: 2008-11-18
Classification: G02B

Abstract:
1. An area light source comprising: a light guide having a plurality of light receiving portions, each of the light receiving portions being arranged side-by-side along a longitudinal direction, a prism group arranged at an irradiation area of each of the light receiving portions, the prism group including a plurality of prisms, each of the prisms being arranged side-by-side along the longitudinal direction; and a plurality of light emitting diode devices, each of the light emitting diode devices being arranged so that an optical center axis of each the light emitting diode device corresponds to a center axis of each of the irradiation areas, the light emitting diode devices facing the irradiation areas at a predetermined distance, wherein an apex angle of each of the prisms in the prism group changes symmetrically to the center axis, in both directions away from the center axis, along the longitudinal direction of the irradiation area.