The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 21, 2002
Filed:
Oct. 31, 2000
Yoshihiro Hama, Saitama-ken, JP;
Yasushi Suzuki, Saitama-ken, JP;
Taminori Odano, Saitama-ken, JP;
Susumu Mikajiri, Chiba-ken, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
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.