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:
Jan. 07, 2014
Filed:
Jan. 29, 2009
Makoto Hirakawa, Kanagawa, JP;
Yoshinori Hayashi, Kanagawa, JP;
Makoto Hirakawa, Kanagawa, JP;
Yoshinori Hayashi, Kanagawa, JP;
Ricoh Co., Ltd., Tokyo, JP;
Abstract
An optical scanning device that scans a scanning surface with a light beam includes a light source that emits the light beam and a pre-deflector optical system that includes at least one diffractive optical element including a diffraction surface having no power at room temperature. The diffraction surface has a multi-step shape having a plurality of zone surfaces substantially perpendicular to an optical axis and a plurality of step surfaces each adjacent to each of the zone surfaces. On a cross sectional plane of the diffraction surface including the optical axis, each of the zone surfaces and each of the step surfaces makes an obtuse angle.