Optical scanning apparatus capable of reducing variations in shading and improving light usage

摘要

An optical scanning apparatus reduces shading and variations in light intensity and significantly increases light usage during an optical scanning process using a simple construction in which a laser beam from a light source is deflected by a light deflector having a reflective surface and is focused to a spot upon a scanning surface by a scanning lens to thereby perform optical scanning. The light source is arranged to produce a laser beam which includes both P-polarized light and S-polarized light. A direction of polarization of the light source is inclined in a plane perpendicular to the optical axis with respect to both the deflecting direction (the Y-axis direction) and a direction perpendicular to the deflecting direction (Z-axis direction). The laser beam impinges upon the reflective surface as polarized light which is between P-polarized light and S-polarized light, such that shading is minimized and variations in light intensity are significantly reduced and light usage is greatly increased during the optical scanning process.