LIGHT GUIDE PLATE, SURFACE ILLUMINATION DEVICE, LIQUID CRYSTAL DISPLAY DEVICE, AND MANUFACTURING METHOD FOR THE LIGHT GUIDE PLATE

摘要

Provided are a light guide plate that can improve light use efficiency and luminance distribution characteristics and allows a decrease in thickness, a surface illumination device, a liquid crystal display device, and a method of manufacturing light guide plates. A light guide plate (4) is equipped with a light projection surface (41), a light reflection surface (42) that faces the light projection surface (41), and a light incident surface (43a) having a protrusion (43c) that continues along the edge of the light projection surface (41). The light incident on the protrusion (43c) enters the same, undergoes total reflection at the inner surface of the light incident surface (41), and is diffused inside the light guide plate (4). The protrusion (43c) can effectively shield incident light compounds projected toward the upper portion of the light incident surface (43a), which improves the light use efficiency as well as the luminance distribution characteristics. The light guide plate (4) is manufactured by means of punching press process.