PLANAR LIGHT SOURCE DEVICE

摘要

A light guide plate (63) is provided with a light introducing section (65) having a thickness larger than that of a light guide plate main body (64) at an end of the light guide main body (64).  A spot light source (62) is permitted to face an end surface (light incoming end surface (66)) of the light introducing section (65).  The light introducing section (65) has a large thickness with a protruding section which has a shape of a half circular truncated cone and protrudes from a surface of the light guide plate (63), and the outer circumferential surface of the protruding section is an inclined surface (67).  On the inclined surface (67), a directivity conversion pattern (68) is configured by arranging V-groove structures (68a) along the outer circumferential surface of the protruding section.  Furthermore, on an inner circumferential section of the directivity conversion pattern (68), an auxiliary inclined surface (71) having an inclination angle smaller than that of the inclined surface (67) is formed along the inner circumferential edge of the directivity conversion pattern (68).