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:
Mar. 12, 1991
Filed:
Jul. 13, 1989
Applicant:
Inventors:
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ; H04N / ;
U.S. Cl.
CPC ...
3501622 ; 350167 ; 350311 ; 358331 ;
Abstract
An optical low-pass filter formed in a trapezoid wave profile having the top and bottom sides of lengths 'a' and 'b' respectively, a height '.delta.' thereof and a length of one period thereof and made from a material having a refractive index 'n', and satisfying the following conditions: for a wavelength of .lambda..sub.M .gtoreq.1.6 .lambda.m, ##EQU1## wherein .lambda..sub.M and .lambda.m are respectively maximum and minimum wavelengths in a wavelength range in which the filter works, and MIN(x,y) represents the smaller one of values which variables x and y take.