Patent ID: 8081355
Filing Date: 2011-12-20
Classification: G03B

Abstract:
1. An illumination unit for use in an image read apparatus which illuminates a surface of an original document with illumination light, reads an image of the original document by a light receiving element, and adjusts an amount of specular light reflection from the surface of the original document on a light receiving plane of the light receiving element by adjusting at least one of an incident angle of the illumination light and a divergence thereof, the illumination unit, comprising a plurality of light source units arranged in a direction and emitting light as the illumination light, wherein the light source units are arranged so as to satisfy the following expression: where θa is a half-value angle of intensity of the light emitted from the light source units, and D is a length of an exit plane of the light in the direction of arrangement of the light source units.