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:
Aug. 03, 2004
Filed:
Jun. 16, 2003
Motonobu Kawabata, Kyoto, JP;
Masahiko Kokubo, Kyoto, JP;
Dainippon Screen Mfg. Co., Ltd., Kyoto, JP;
Abstract
An optical scanner according to the present invention comprises a first imaging optical system consisting of a collimator lens and a cylindrical lens, a light deflector reflecting/deflecting a light beam for scanning, and a second imaging optical system consisting of an f-&thgr; lens and an anamorphic lens. The f-&thgr; lens has three groups of lenses, i.e., a first lens having negative refracting power, a second lens having positive refracting power and a third lens having positive refracting power. The f-&thgr; lens is formed to satisfy relational expressions L/f<0.100 and 0.10≦r1/r3≦0.26, where L represents the total length of the f-&thgr; lens, f represents the focal distance of the f-&thgr; lens, r1 represents the radius of curvature of a light beam entrance-side refracting interface of the first lens and r3 represents the radius of curvature of a light beam entrance-side refracting interface of the second lens. Thus, a compact optical scanner comprising an f-&thgr; lens having a small total length L and high optical performance is provided also when increasing a focal length f as well as a scanning line length W.