Patent ID: 8939633
Filing Date: 2015-01-27
Classification: G02B

Abstract:
1. An area light source device comprising: a light guide plate including: a light incident end face, a light guide plate main body thinner than a thickness of the light incident end face, and a light introducing unit formed in continuation with the light guide plate main body and so that thickness gradually becomes thinner from the light incident end face side towards the light guide plate main body side; a light source arranged at a position facing the light incident end face; a diffuser plate and one or more prism sheets arranged on a surface on a light emission side of the light guide plate main body; and a light shielding sheet arranged on an upper side of the diffuser plate and the prism sheet in a region excluding a light emitting region of the light guide plate main body; wherein at least one of the one or more prism sheets is extended towards a front surface of the light introducing unit, and wherein at least one extended prism sheet of the one or more prism sheets is arranged so that a prism ridge direction forms an angle of greater than or equal to 30° and smaller than or equal to 90° with respect to a direction perpendicular to the light incident end face.