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:
Nov. 27, 1990
Filed:
May. 25, 1989
Toshiba Lighting & Technology Corporation, Tokyo, JP;
Abstract
An arc tube bulb comprises a sealed portion formed at one end of the bulb and an enclosure portion formed at the other end to surround a discharge space. A pair of metal foils are buried in the sealed portion. A rare gas for start-up, mercury and a metal halide are charged in the discharged space. A pair of electrodes comprise a pair of electrode rods connected to the metal foils and coils disposed at the tips of the rods. These coils are positioned within the discharge space apart from each other and facing each other. The lamp is lit when the value of the input power WL (watt) divided by the inner surface area S (cm.sup.2) of the discharge space falls within the range of between 20 and 70, i.e., 20.ltoreq.WL/S.ltoreq.70. The surface region of the electrode rods is formed of a pure rhenium metal or a rhenium-tungsten alloy. Since the pure rhenium metal or rhenium-tungsten alloy has a low thermal conductivity, the temperature elevation of the electrode rod can be suppressed in the single end-sealed metal halide lamp of the particular construction.