Patent ID: 7277229

Claim:
A linear light beam generating optical system comprising a plurality of semiconductor lasers arranged in the direction of the slow axis of the laser beam emitted from each semiconductor laser, an optical means which collimates at least a component in the direction of the fast axis of each of the laser beams emitted from the plurality of the semiconductor lasers and makes at least two of the collimated laser beams parallel to each other, an optical member which is provided with a light inlet face and a light outlet face which are positioned in substantially perpendicular to the optical axis of each laser beam and a pair of total internal reflection surfaces which are opposed to each other at a space where the component in the direction of the slow axis of the laser beam entering from the light inlet face repeats total internal reflection, and emits from the light outlet face a slow axis uniform laser beam which is uniformed only in the intensity distribution of the component in the direction of the slow axis, an inlet optical means which causes the laser beams emitted from the plurality of the semiconductor lasers to enter the light inlet face of the optical member, and an imaging optical means which images the slow axis uniform laser beam on a predetermined surface to be exposed like a linear line beam extending in the direction of the slow axis.