Patent ID: 6831764
Filing Date: 2004-12-14
Classification: G02B

Abstract:
A light scanning device having an imaging optical system for guiding a light beam emitted from light source means to a deflecting element, and forming the light beam deflected by the deflecting element into an image on a surface to be scanned,wherein said imaging optical system is formed from a single lens, sectional shapes of an incident surface and an exit surface of said single lens in a main scanning direction are non-arc shapes, power of the exit surface in a sub scanning direction satisfies 0.9&lE;&phgr;s2/&phgr;s&lE;1.1 where &phgr;s is power of the overall imaging optical system in the sub scanning direction and &phgr;s2 is power of the exit surface in the sub scanning direction, and the non-arc shape of the exit surface in the main scanning direction satisfies 0.9Ã—LboLao&leq;Lb&it;â€ƒ&it;Î¸La&it;â€ƒ&it;Î¸&leq;1.1Ã—LboLaowhere Lao is an equivalent air distance from the deflecting means on an optical axis to the exit surface of said single lens, Lbo is a distance from the exit surface of said single lens to the surface to be scanned, La&thgr; is an equivalent air distance from the deflecting means at an off-axis position to the exit surface of said single lens, and Lb&thgr; is a distance from the exit surface of said single lens to the surface to be scanned.