Patent ID: 6400486
Filing Date: 2002-06-04
Classification: G02B

Abstract:
A scanning optical system, comprising:a light source that emits a light beam; a deflector that deflects the light beam emitted by said light source to scan, in a main scanning direction, within a predetermined angular range; a scanning lens system that converges the light beam deflected by said deflector on a surface to be scanned; said scanning lens system having positive power, said scanning lens system having a plurality of lens surfaces, a diffractive lens structure being formed on at least one of said plurality of lens surfaces, said diffractive lens structure compensating for aberration in the main scanning direction caused by characteristics of a refractive lens structure of said scanning optical system, an axis that connects a front focal point and a rear focal point of said diffractive lens structure being shifted in an auxiliary scanning direction that is perpendicular to the main scanning direction with respect to an optical axis of the refractive lens structure of said scanning lens system.