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. 20, 1992
Filed:
Nov. 13, 1990
Applicant:
Inventors:
Alex L Halberstadt, London, GB;
John A Letchford, Middlesex, GB;
Assignee:
Thorn Emi plc, London, GB;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
392408 ; 392407 ; 313112 ; 313579 ; 313572 ; 313634 ; 313580 ; 219553 ;
Abstract
A tungsten halogen lamp producing infra red radiation, for example for cooking or heating, has an envelope of high silica content material sealed at each end by a pinch seal. A gas fill is at a room temperature pressure of 250-750 mm Hg. A portion of the envelope at each end is clear and the rest contains an opacifier which reduces transmission of visible light. A suitable opacifier is red, being produced by the reduction of copper oxide dispersed in the high silica content material. The envelope is produced by butt joining clear end sections and a tube of material containing opacifier.