Optical scanning device, image forming apparatus and liquid crystal device driving method

摘要

An optical scanning device includes: a light source; a deflector deflecting light beam from the light source; a coupling lens carrying out coupling of the light beam from the light source; a first optical system leading the light beam from the coupling lens to the deflector; a scanning optical system leading the light beam deflected by the deflector to a to-be-scanned surface; and a phase-modulatable liquid crystal device disposed on a light path lying from the light source through the to-be-scanned surface and driven by an electric signal, wherein: the first optical system at least comprises an optical device having: a surface having power positive in a sub-scanning direction; and a surface having power positive in a main scanning direction.