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:
Jul. 05, 2016
Filed:
Jun. 04, 2015
Canon Kabushiki Kaisha, Tokyo, JP;
Hidefumi Iwasa, Yokohama, JP;
Hideo Ukuda, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A laminated diffractive optical element including a colorant-containing first layer having a diffraction grating surface with a grating height X and a second layer closely stacked on the diffraction grating surface of the first layer, wherein the relation of internal transmittances Tand Tof a material (a) for forming the first layer and a material (b) for forming the second layer satisfies the following (Formula 1) and the relation of the maximum and minimum internal transmittances Tand Tof the laminated diffractive optical element satisfies the following Formula (2):2.0%≦||  (Formula 1)≦8.0%  (Formula 2)This reduces shading on the image surface resulting from the difference in transmittance of the optical element to provide a laminated diffractive optical element having reduced variation in transmittance.