Patent ID: 6133935
Filing Date: 2000-10-17
Classification: G02B

Abstract:
An optical scanning apparatus comprising:light source means;a deflecting device for deflecting a luminous flux emitted from said light source means;optical means for guiding the luminous flux emitted from said light source means to a deflecting surface of said deflecting device; andan optical device for forming the luminous flux which has been deflected by said deflecting device into a spot-shaped image on a plane to be scanned;wherein said optical device has a first toric lens and a second toric lens disposed in the mentioned order from said deflecting device;in a main scanning cross section said first toric lens has both lens surfaces thereof formed to aspherical shapes and has a meniscus shape which provides a concave surface facing said deflecting device in a vicinity of a center of scanning and which provides a positive refractive power;in the main scanning cross section said second toric lens has both lens surfaces thereof formed into aspherical shapes and has a meniscus which provides a convex surface facing said deflecting device in the vicinity of the center of scanning and which provides a positive refractive power; andlens sections of said first toric lens and said second toric lens perpendicular to a generating line, in a sub-scanning cross section, both have meniscus shapes which provide concave surfaces facing said deflecting device and which provide a positive refractive power.