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:
Jan. 31, 2007
Susumu Abe, Utsunomiya, JP;
Sayoko Amano, Utsunomiya, JP;
Susumu Abe, Utsunomiya, JP;
Sayoko Amano, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An ND filter including an alternating layer which is composed of two films being alternately stacked and formed on a transparent substrate, the two films having different refractive indexes, wherein the alternating layer has a substrate-side reflected light attenuating multi-layered film and a transmittance adjusting multi-layered film formed on the transparent substrate in the stated order from the transparent substrate side, and the light absorption amount of the substrate-side reflected light attenuating multi-layered film is set to be 20% or more and 30% or less. Thus, an ND filter having satisfactory front surface reflection characteristics and rear surface reflection characteristics can be stably obtained while the transmittance of 4% or more and 11% or less is maintained with respect to the entire visible region (400 nm or more and 700 nm or less).