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:
Jun. 24, 2003
Filed:
Jan. 29, 2001
Ingrid Josef Maria Snijkers-Hendrickx, Eindhoven, NL;
Remy Cyrille Broersma, Eindhoven, NL;
Rene Jan Hendriks, Eindhoven, NL;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
The present invention relates to an improved maintenance, low-pressure mercury vapor discharge lamp having a discharge vessel enclosing a discharge space provided with a filling of mercury and a rare gas in a gastight manner. The discharge vessel is made from a glass of essentially 60-80% by weight SiO and 10-20% by weight Na O. Preferably, the composition of this so-called sodium-rich glass is made of 70-75% by weight SiO , 15-18% by weight Na O and 0.25-2% by weight K O. At least a part of the inner surface of the discharge vessel is provided with a transparent layer having a borate or a phosphate of an alkaline-earth metal and/or of scandium, yttrium or another rare earth metal. Preferably, the alkaline-earth metal is calcium, strontium and/or barium. In a particularly preferred embodiment, the transparent layer is made of yttrium borate and strontium borate. Additionally, the transparent layer preferably has a thickness between 5 and 200 nm and has provided on it a luminescent layer.