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. 08, 2014
Filed:
Nov. 18, 2010
Mikio Kobayashi, Utsunomiya, JP;
Mikio Kobayashi, Utsunomiya, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
A diffractive optical element includes multiple diffraction gratings laminated and made of at least three material types, wherein the multiple diffraction gratings include: a first combination part including two diffraction gratings of materials different from each other in which grating side surfaces of grating parts contact with each other or are disposed close to each other in a grating pitch direction; and a second combination part including two diffraction gratings of materials different from each other in which at least one material is different from the materials of the first combination part; and when N1Aw and N1Bw denote refractive indices of the first combination part at a wavelength (w), ν1A and ν1B denote Abbe numbers, N2Ad and N2Bd denote refractive indices of the second combination part on a d-line, ν2A and ν2B denote Abbe numbers, the wavelength (w) is 370<w<730 (nm). The followings are satisfied:11=0;16<(ν1−ν1)<75;0.03<|22|<0.5; and16<(ν2−ν2)<75.