Light guide, illuminating device having the light guide, and image reading device and information processing apparatus having the illuminating device

摘要

An illumination unit comprises an elongated light guide (3); a light source (8) that injects light into an end surface of said light guide (3), in a longitudinal direction of said light guide (3); a light output surface, formed on a side of said light guide (3) along the longitudinal direction thereof, that outputs in a line shape light injected from said light source (8) into the end surface of said light guide (3); and an elongated reflector (5) formed along the longitudinal direction on another side of said light guide (3) different than the side of said light guide (3) on which said light output surface is formed, wherein the reflector (5) is arranged so that a normal line passing through a center of a width of said reflector (5) is offset from a center of said light source (8).