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. 18, 1980
Filed:
Jan. 18, 1978
TDK Electronics Co., Ltd., Tokyo, JP;
Abstract
A thermal printing head for printing alphanumeric characters on a thermally-responsive medium, the head being faced with a pattern of heat generating 'dot' elements electrically insulated from one another and having conductive leads, with means for connecting the leads selectively to a source of electric current. The heat generating elements are formed of a film of boron phosphide. Preferably the leads are also formed of boron phosphide, integral with the elements, but 'doped' to secure a high degree of conductivity. The printing head is formed by applying a boron phosphide compound on a substrate, covering the same with a passivation film, removing the passivation film to expose a background area of the compound film defining a central 'island' of unexposed area, doping the exposed background area to increase the conductivity thereof, removing the passivation film from the island, and forming grooves in the compound film dividing the island into separate heat generating elements, with the grooves extended into the background area to form pairs of integral conductive leads for the elements.