Patent ID: 7554708
Filing Date: 2009-06-30
Classification: G02B

Abstract:
1. An optical scanning device comprising: a first optical element that converts a cross-section shape of a light beam from a semiconductor laser to a desired shape; a second optical element that guides the light beam output from the first optical element to an optical deflector that deflects the light beam; and a third optical element that gathers the light beam deflected by the optical deflector onto a surface to be scanned to form a light spot thereby optically scanning the surface, wherein at least one of lenses forming the first optical element and the second optical element includes a resin-made lens, at least one of resin-made lenses satisfies conditions (1) to (4): (1) only one surface of the resin-made lens has a diffracting surface where P1 is a power in any of a main scanning direction and a sub-scanning direction of a diffracting portion on a diffracting surface of the resin-made lens, P2 is a power of a refractive portion on the diffracting surface in the direction defined in P1, and P3 is a power on a surface other than the diffracting surface of the resin-made lens in the direction defined in P1.