LIGHT GUIDE PLATE

摘要

A light guide plate (1) formed in a plate shape having a plane of incidence (5) on its side face and a plane of outgoing (3) on its upper or lower face. Polarizing pattern elements (17) of roughly quadrangular pyramid shape formed in a direction for reducing their wall thickness more than the wall thickness of the general wall thickness of the light guide plate (1) are arranged, adjacent to each other, on the surface thereof facing the plane of outgoing (3). The shape of the quadrangular pyramid is such that four faces thereof other than the bottom face are formed integrally with the light guide plate (1). The areas of the first and second faces of the four faces other than the bottom face are 20 times the areas of the other third or fourth face or larger, the ridge lines of the first and second faces perpendicularly crosses the plane of incidence (5), and the inclination angles of the first and second faces relative to the plane of outgoing (3) are within the range of 0.5 to 3°. The areas of the first and second faces are approximately the same and the areas of the third and fourth faces are approximately the same to prevent the brightness of the areas thereof near the plane of incidence from increasing or decreasing.