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:
Feb. 03, 1998
Filed:
May. 22, 1996
Applicant:
Inventors:
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ; G02B / ;
U.S. Cl.
CPC ...
359888 ; 359885 ; 359589 ; 359580 ;
Abstract
A thin-film-type ND filter which attenuates the amount of light transmission is formed on a transparent substrate by using two or more types of metallic oxide having a refractive index n and an attenuation coefficient k which are in the range of 1.0 to 3.0 in the wavelength region of the visible region, making it possible to obtain flat transmittance characteristics.