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:
Apr. 25, 1978
Filed:
Jun. 16, 1976
Kazuo Ishikawa, Yokohama, JA;
Keiichi Sakaguchi, Yokohama, JA;
Tomoshi Takigawa, Machida, JA;
Noritsugu Hirata, Yokohama, JA;
Akira Tajima, Kawasaki, JA;
Sadahiko Tsuji, Yokohama, JA;
Canon Kabushiki Kaisha, Tokyo, JA;
Abstract
In a diaphragm device for use in an optical instrument such as a camera and having two or more diaphragm blades movable across an imaging path of rays and arranged in axially displaced relation from each other to define a common aperture of variable size, there is provided means formed in a portion of at least one of the diaphragm blades to substantially either eliminate or reduce the axial displacement between the diaphragm blades at a relatively small aperture region, whereby the distribution of light energy is made uniform over the entire area of the image.