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:
May. 04, 2010
Filed:
Oct. 05, 2007
Hiroto Yasui, Utsunomiya, JP;
Hiroto Yasui, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
The diffractive optical element includes two diffraction gratings made of different materials and being in contact with each other at their grating surfaces. The materials satisfy the following conditions, and the second material is obtained by mixing a resin material with a particulate material satisfying the following conditions: nd1≧1.48, νd1≧40, (−1.665E−07×νd1+5.213E−05×νd1−5.656E−03×νd1+0.675)≦θg,F1≦(−1.665E−07×νd1+5.213E−05×νd1−5.656E−03×νd1+0.825), (−1.687E−07×νd1+5.702E−05×νd1−6.603E−03×νd1+1.400)≦θg,d1≦(−1.687E−07×νd1+5.702E−05×νd1−6.603E−03×νd1+1.580), nd2≦1.6, νd2≦30, θg,F2≦(−1.665E−07×νd2+5.213E−05×νd2−5.656E−03×νd2+0.675), θg,d2≦(−1.687E−07×νd2+5.702E−05×νd2−6.603E−03×νd2+1.400), nd1−nd2>0, ndb2≧1.70, νdb2≦20. The element achieves a high diffraction efficiency in a specific diffraction order over a wide wavelength range.