LIGHT GUIDE PLATE AND SURFACE LIGHT SOURCE DEVICE

摘要

PROBLEM TO BE SOLVED: To make a uniform brightness attained by adding a lenticular lens on the upper surface of the light guide plate main body and restrict a reduction of a light utilization efficiency and occurrence of bright line by arranging the lenticular lens in a surface light source device in which a pair of cylindrical surfaces are formed at an inclination surface of a light guide plate.SOLUTION: A light guide plate 43 is comprised of a light feeding part 44 and a light guide plate main body 45. The upper surface of the light feeding part 44 is provided with an inclination surface 46 inclined from a portion thicker than the light guide plate main body 45 toward the end part of the light guide plate main body 45. In addition, the inclination surface 46 is formed with a groove 51 by two cylindrical surfaces 50 arranged at the inclination surface 46 to be cut. An axial center of the cylindrical surface 50 is inclined with upper one becoming near the light incident plane, an inclination angle of the inclination surface 46 is smaller than an inclination angle that the axial center of the cylindrical surface 50 forms with the surface of the light guide plate main body 45.