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. 09, 2006
Filed:
Dec. 23, 2003
Yasunori Murata, Tokyo, JP;
Susumu Abe, Kanagawa, JP;
Daisuke Ito, Tochigi, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
To provide an ND filter and a light amount adjusting device, in which a deterioration of optical performance of an optical system is small, and in addition, an optical system having the light amount adjusting device, and an optical device having the optical system. More specifically, an ND filter according to the present invention includes: a base that transmits light having a predetermined wavelength λ; and a filter member selectively formed on the base, in which: a transmittance of the filter member gradually changes in a region in a predetermined direction; and a phase difference which is produced between light transmitting through the filter member and light transmitting through a region on the base in which the filter member is not formed is λ/5 or less in a boundary of the filter member.