Patent ID: 7646521
Filing Date: 2010-01-12
Classification: G02B,G03G,H04N

Abstract:
1. An optical scanning device comprising: a light source; a first optical element that converts light emitted from the light source to parallel light; a deflection element that deflects the light in a fast scanning direction to scan a surface of an object to be scanned with the light at a constant speed; a second optical element that guides the light to the deflection element; and a third optical element that focuses the light deflected by the deflection element onto the surface of the object to be scanned, at least one surface among surfaces of the third optical element that intersect the light including a surface form which affects only one of fast scanning direction characteristics or slow scanning direction characteristics at an image plane, wherein the at least one surface among the surfaces of the third optical element that intersect the light includes a surface form that corrects, in the slow scanning direction, a scanning line form and a focusing characteristic along the surface to be scanned, and that does not have lens power in the fast scanning direction, and the at least one surface is described by the following equation, with coordinates being represented by (x,y,z), coordinate in the slow scanning direction being x, coordinate in the fast scanning direction being y, and coordinate in an optical axis direction being z, C the at least one surface being a surface which is made by linking circular arcs which have curvature radii R(y) determined for positions y in the fast scanning direction with a generatrix produced by x1(y) in the x-y plane serving as peak points,