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:
Oct. 16, 1990
Filed:
Sep. 22, 1989
Applicant:
Inventors:
Masaichi Sato, Tokyo, JP;
Hideo Imazeki, Tokyo, JP;
Assignee:
Ando Electric Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
350403 ; 350400 ;
Abstract
There is provided an optical adder for accurately and additively specifying variable optical attenuation, which comprises a quarter wave plate disposed on an optical axis for changing an incident linearly polarized light beam emanating from a light source to a circularly polarized light beam; and one or more neutral density filter plates all disposed on the optical axis next to said quarter wave plate for attenuating the incident circularly polarized light beam respectively additively by a predetermined amount.