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. 02, 2004
Filed:
Aug. 23, 2002
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A discharge lamp is disclosed comprising an enclosed discharge vessel for the generation of an electrical discharge and a casing made of glass which surrounds the discharge vessel. In order to achieve as constant properties as possible over the service life of the lamp, it is proposed that the glass material of the casing be doped with sodium in a concentration of at least 10 ppm, and preferably at least 30 ppm. According to a further embodiment, it is proposed that other alkali metals (except for sodium) be contained in a maximum concentration of 25 ppm. Surprisingly, by the appropriate choice of the outer bulb, not in direct contact with the actual discharge, the diffusion of sodium from the discharge vessel is reduced. In addition to this, the material of the outer bulb has a reduced inclination to crystallization.