Light guide optical system, document illuminating device using same, and image reading apparatus using same

摘要

A light guide optical system guides a plurality of light beams emitted from a plurality of point light sources arranged linearly to a predetermined surface. The light guide optical system has a plurality of optical surfaces arranged periodically in the arrangement direction of the plurality of point light sources. Each of the plurality of optical surfaces has power in the arrangement direction of the plurality of point light sources.