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. 20, 2013
Filed:
Feb. 06, 2012
Hirofumi Abe, Utsunomiya, JP;
Hirofumi Abe, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A light quantity adjustment device includes: an aperture mechanism that varies an aperture opening through drive of aperture blades to restrict a quantity of light that passes through the aperture opening; and an ND filter inserted in and removed from an optical path on a light incident side or a light exit side of the aperture opening. The ND filter has a distribution of transmittance in which the transmittance differs in a direction of interposition of the ND filter in the optical path of the aperture opening, and includes a recessed portion formed by recessing a center portion of a distal-end region of the ND filter on a side of interposition in the optical path of the aperture opening in a direction opposite the direction of interposition.