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. 07, 2013
Filed:
Jul. 24, 2012
Koji Miyasaka, Fukushima, JP;
Hiromasa Sato, Fukushima, JP;
Koji Miyasaka, Fukushima, JP;
Hiromasa Sato, Fukushima, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
There is provided a diffraction grating including a convex portion and a concave portion which are used for lights having different wavelengths λ, λand λand are alternately disposed on at least one surface of a substrate with a predetermined pitch. An average refractive index of the convex portion is smaller than an average refractive index of the concave portion. A phase difference in the lights having the wavelength λwhich transmit the convex portion and the concave portion and a phase difference in the lights having the wavelength λwhich transmit the convex portion and the concave portion are both substantially the integral multiple of 2π, and a phase difference in the lights having the wavelength λwhich transmit the convex portion and the concave portion is substantially the non-integral multiple of 2π.