DOCUMENT ILLUMINATING METHOD, DOCUMENT ILLUMINATING DEVICE, AND IMAGE READER

摘要

A document illuminating method and device for illuminating a document with higher efficiency with light emitted from a light source. The method for illuminating a document with light emitted from a light source includes a step of illuminating a document with light produced by combining lights emitted from light sources arranged at least in a first direction and a step of diffusing the light beams emitted from the light sources so that each light beam is diffused to a light bema having a width two or more times the interval between adjacent light sources of the light sources in the first direction. The document illuminating device for illuminating a document with light emitted from a light source comprises light sources arranged at least in a first direction, and an optical system for combining lights emitted from the light sources, illuminating the document with the combined light, and diffusing each of the light beams emitted from the light sources to a light beam having a width two or more times the interval between adjacent light sources of the light sources in the first direction.