Color image reading apparatus

摘要

In a color image reading apparatus, a plurality of line sensors are arranged on a same substrate and an image of an object is formed on the sensors by an imaging optical system. A blazed diffraction grating is disposed in an optical path between the imaging optical system and the sensors so as to color-separate a light beam from the object into a plurality of color light beams. A correction element such as a plane-parallel glass, prism or the like is disposed in an optical path between the blazed diffraction grating and the sensors so as to correct different imaging positions on the surfaces of the sensors caused by different wavelengths of the plurality of color light beams color-separated by the blazed diffraction grating. By the correction element, respective optical paths of the color light beams are changed utilizing different refractive indices due to different wavelengths upon being transmitted through the correction element so as to make spacing between adjacent color light beams color-separated in a sub scanning direction equal to each other on the surfaces of the sensors.