Greenblum & Bernstein, P.L.C.
Multi-beam scanning optical system
A multi-beam scanning optical system is provided with a light source unit, polygonal mirror, and an f&thgr; lens. The f&thgr; lens includes first, second and third lenses. The beams emitted by the light source unit are incident on the first, second and third lenses in this order. The first lens consists of two lens elements, the first lens element converges the plurality of beams in an auxiliary scanning direction. The second lens element converges the plurality of beams in a main scanning direction. A plurality of convex surfaces, which correspond to the plurality of beams and converge the plurality of beams in the auxiliary scanning direction, respectively, are formed on one of surfaces of the first and second lens elements. Further, a diffraction lens structure for compensating for lateral chromatic aberration caused by a refraction lens structure of the f&thgr; lens system is formed on each of the plurality of convex surfaces.
Asahi Kogaku Kogyo Kabushiki Kaisha
G B H
G02B B41J H04N
inventional inventional inventional
Susumu Taminori Yoshihiro Yasushi
Mikajiri Odano Hama Suzuki