Patent ID: 6992807
Filing Date: 2006-01-31
Classification: G02B

Abstract:
1. An optical scanning apparatus provided with: light source means; deflecting means for deflecting a beam emitted from said light source means; and a scanning optical system having a plurality of scanning lenses for directing the beam deflected by said deflecting means onto a surface to be scanned; wherein of said plurality of scanning lenses, a first scanning lens nearest to the deflecting means is such that the shape thereof in a main scanning cross section is a meniscus shape having positive refractive power, and satisfies a condition that where fm is a focal length of said scanning optical system in the main scanning cross section, and d 1 is a central thickness of the first scanning lens, and a second scanning lens nearest to the surface to be scanned is such that in the main scanning cross section, the shape of a light incidence side surface thereof is an aspherical shape free of an inflection point or an arcuate shape, and satisfies a condition that where R 3 is a radius of curvature of said light incidence side surface on an optical axis thereof in the main scanning cross section, and wherein the first scanning lens is such that in a sub-scanning cross section, both surfaces thereof are of a convex shape.