Patent ID: 8223418

Claim:
An optical scanning device that scans a scanning surface with a light beam in a main-scanning direction, the optical scanning device comprising: a light source that emits the light beam; a first optical system that couples the light beam from the light source, the first optical system including a first lens made of glass having a positive power and a second lens made of plastic having a negative power at least along a direction corresponding to the main-scanning direction; and a second optical system that focuses the light beam from the first optical system onto the scanning surface and moves a light spot obtained by focusing the light beam on the scanning surface in the main-scanning direction, wherein one of an incidence plane and an output plane of the first lens is spherical while other of the incidence plane and the output plane is spherical or flat, wherein a cross-sectional plane of the second lens at least along the direction corresponding to the main-scanning direction has a non-arc shape on at least one of an incidence plane and an output plane of the second lens, and wherein the power of the first lens is larger than the power of the second lens in magnitude.