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:
Jan. 08, 1991
Filed:
Apr. 11, 1988
Simon N Balderson, Reading, GB;
Thorn EMI plc, London, GB;
Abstract
A heating unit includes a heatable surface. At least a region of the heatable surface is coated or otherwise provided with a layer incorporating a thermochromic material in sufficient quantity to influence the perceived color of the layer. The thermochromic material exhibits an absorption edge wavelength which changes reversibly with temperature in the range of from 20.degree. C. to at least 400.degree. C. The absorption edge wavelength is at least 540 nm at 20.degree. C. and progressively increases to at most 700 nm at 400.degree. C. Such a heating unit is able to provide a visual indication of whether or not the heatable surface is still hot once the power has been switched off. Useful thermochromic materials include Cd(S.sub.1-x Se.sub.x) and (Zn.sub.1-y Mn.sub.y)O.