Patent ID: 9182530
Filing Date: 2015-11-10
Classification: G02B

Abstract:
1. A light guide plate having a light exit surface, a back surface opposed to the light exit surface, at least one light entrance surface consisting of a part of a side surface between the light exit surface and the back surface, and a counter surface consisting of a part of the side surface and opposing the one light entrance surface in a first direction, said light guide plate comprising: a body portion; first unit optical elements arranged on a one-side surface of the body portion in an arrangement direction intersecting the first direction, each element extending in a direction intersecting the arrangement direction; and second unit optical elements disposed between first unit optical elements on the one-side surface of the body portion; wherein when the light exit surface is viewed in a normal direction of the one-side surface of the body portion, a proportion of an area occupied by the first unit optical elements in the light exit surface is larger in a central area, the central area containing a center between the light entrance surface and the counter surface on the one-side surface of the body portion and extending between both ends of the one-side surface of the body portion in a second direction perpendicular to the first direction, than in an end area containing a light entrance surface-side end of the one-side surface of the body portion and extending between both ends of the one-side surface of the body portion in the second direction; wherein when the light exit surface is viewed in the normal direction of the one-side surface of the body portion, a proportion of an area occupied by the second unit optical elements in the light exit surface is smaller in the central area than in the end area; wherein a light exit surface angle of each first unit optical element, which is the angle of a light exit-side surface of the first unit optical element with respect to the one-side surface of the body portion in a main cross-section parallel to both the normal direction of the one-side surface of the body portion and the arrangement direction of the first unit optical elements, changes in at least one portion or region between an apex, the farthest point from the one-side surface of the body portion, and each base end, the closest portion to the one-side surface of the body portion, in the light exit-side surface of the first unit optical element such that the light exit surface angle solely increases from that at the apex to that at the base end; and wherein in a cross-sectional shape of each first unit optical element in a main cross-section parallel to both the normal direction of the one-side surface of the body portion and the arrangement direction of the first unit optical elements, and containing the center on the one-side surface, a shape of a part of each first unit optical element containing an apex, the farthest point from the one-side surface of the body portion, is identical to the cross-sectional shape of a whole of each second unit optical element in the main cross-section parallel to both the normal direction of the one-side surface of the body portion and the arrangement direction of the first unit optical elements.