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:
Jun. 21, 1988
Filed:
Feb. 26, 1986
Applicant:
Inventors:
Assignee:
Siemens Aktiengesellschaft, Munich, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
422 56 ; 436169 ;
Abstract
The present invention is directed to an optical filter that includes a mixture of at least one basic or acid color former or dye, preferably being a triphenyl methane system and at least one complementary acid or basic compound. The mixture reversibly changes color in response to a gas or vapor. The mixture may be embedded in a matrix substance and/or may be applied to a carrier. The color change may be measured photo-electrically.