Illumination device

摘要

To provide an illumination device in which there is no variation in light intensity distribution of the illumination device, and in which illumination spots, particularly light intensity spots, are not prone to occur in a read image in an image reading device, by maintaining a constant gap between a light source and an end face of a light guide. The illumination device includes: a light guide having an end face for taking in light, a diffuse reflecting surface for diffusely reflecting the light taken in from the end face, and a light exit surface for emitting the light that is diffusely reflected at the diffuse reflecting surface towards an irradiation surface. The illumination device further include a reflector having a diffuse reflecting surface that reflects light from the light source toward the one end face of the light guide. The light guide has, at the one end, a flange portion that abuts the reflector, the light source is mounted to a circuit board, and the reflector is held between the flange portion of the light guide and circuit board so as to maintain a predetermined gap between the light source and light guide.

主权项

1. An illumination device comprising:
a light guide including one end face for taking in light, a diffuse reflecting surface for diffusely reflecting the light taken in from the one end face, and a light exit surface for emitting the light that is diffusely reflected at the diffuse reflecting surface towards an irradiation surface; a light source facing the one end face of the light guide; and a reflector having another diffuse reflecting surface that reflects light from the light source toward the one end face of the light guide, the light exit surface of the light guide being formed into an arc-like shape, the diffuse reflecting surface being disposed at a position at which an optical axis normal line along which light passes through a center of a circle constituting the arc and emitted from the light exit surface is formed, the light source being mounted on a circuit board formed separately from the light guide and disposed at a position which is set on the optical axis normal line of the diffuse reflecting surface and shifted to the light exit surface side with respect to the center of the circle, wherein the light guide has, at the one end face, a flange portion that abuts against the reflector, and the reflector is held between the flange portion of the light guide and the circuit board so as to maintain a predetermined gap between the light source and the one end face of the light guide.