In color reading including an infrared light source, light reflected by a document focuses on a light-receiving part of a sensor IC with different conjugate lengths, due to color aberration of the rod-lens. Since the wavelength of the infrared light is relatively long, the deterioration of the reading...http://www.google.de/patents/US7166827?utm_source=gb-gplus-sharePatent US7166827 - Contact-type image sensor module and image reading apparatus using the module
