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:
Oct. 06, 1992
Filed:
Oct. 07, 1991
Yasuo Matsumoto, Shizuoka, JP;
Kazunori Murakami, Shizuoka, JP;
Tomonori Ikumi, Shizuoka, JP;
Yasuo Iwafune, Tokyo, JP;
Tokyo Electric Co., Ltd., Tokyo, JP;
Abstract
A postobjective optical scanner comprising a polygonal optical deflector having a plurality of reflecting surfaces each being a curved surface varying in curvature from position to position thereon; and a correcting lens disposed between the polygonal optical deflector and the objective surface on an optical path, and having a rotationally symmetric curved surface of incidence having a cross section having the shape of an arc of a circle with its center on the axis of rotational symmetry, rotationally symmetric with respect to a plane including the axis of rotation of the polygonal optical deflector and perpendicular to the axis of rotational symmetry and having its power in both the feed direction and the scanning direction, and a surface of departure symmetrical with respect to a plane perpendicular to the scanning direction and having its power in the scanning direction. The combined performance of the correcting effects of the polygonal optical deflector and the correcting lens corrects the curvature of image surfaces and f-.theta. characteristics at a high accuracy.