Patent ID: 7385746

Claim:
An optical scanning system, comprising: light source means; deflecting means configured to scanningly deflect a light beam from said light source means in a main scan direction; and an imaging optical system configured to image, upon a surface to be scanned, the light beam deflected by a deflecting surface of said deflecting means; wherein said deflecting surface is configured to perform reciprocating motion by which the surface to be scanned is reciprocatingly scanned in the main scan direction with the light beam deflected by said deflecting surface of said deflecting means; wherein as a result of reflection of the light beam by the deflecting surface, a first phase difference of wavefront aberration is produced in the main scan direction between a marginal ray and a principal ray of the light beam reflected by the deflecting surface at an effective deflection angle of the same corresponding to a largest scan position in an effective scan region on the surface to be scanned; wherein as a result of transmission of the light beam through said imaging optical system, a second phase difference of wavefront aberration is produced in the main scan direction between a marginal ray and a principal ray of the light beam reflected by the deflecting surface at an effective deflection angle thereof; and wherein at least one optical surface constituting said imaging optical system is non-arcuate shape in a main scan section, so that the first and second phase differences are made opposite to each other.