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. 17, 2023
Filed:
Nov. 17, 2021
Canon Kabushiki Kaisha, Tokyo, JP;
Hiroki Yoshida, Tochigi, JP;
Kazumi Kimura, Saitama, JP;
Genichiro Kudo, Tochigi, JP;
Hiroto Kano, Tochigi, JP;
CANON KABUSHIKI KAISHA, Tokyo, JP;
Abstract
An optical systemincludes a front group, a light shielding member, and a rear groupdisposed in order from a side of an object to a side of an image. The light shielding memberhas an opening. The rear grouphas a diffraction surfaceand an aspherical surface. The aspherical surfacein a first section has a non-circular-arc shape. The grating spacing of the diffraction surfacein the first section changes from a center portion toward a peripheral portion to include an extremum value at the center portion. In the first section, the shape of at least one of a base surface of the diffraction surfaceand an optical surface disposed closer than the diffraction surfaceto the side of the object is asymmetric with respect to a normal line at a vertex thereof.