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:
Aug. 10, 1999
Filed:
Mar. 11, 1997
Koito Manufacturing Co., LTD., Tokyo, JP;
Abstract
The invention is directed to preventing occurrence of molybdenum foil breakage during a pinch sealing operation in a method of fabricating an arc tube having a pair of molybdenum foils pinch-sealed on both sides of a spherical portion of a glass tube by sequentially pinch-sealing the respective molybdenum foils. A first molybdenum foil is not pinch-sealed (first pinch seal) with an inert gas introduced into a glass tube as in a conventional embodiment, but is pinch-sealed with the internal pressure of the glass tube maintained at a vacuum of 0.5 torr or less. As a result, oxidation of the molybdenum foils causing breakage of the molybdenum foils during a pinch sealing operation is minimized. Hence, an arc tube having each of a pair of molybdenum foils made of molybdenum whose purity is 99.95% or more and with a thickness of 20 .mu.m or less can be fabricated.