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. 23, 1999
Filed:
Feb. 13, 1998
Jean J Heuvelmans, Eindhoven, NL;
Abraham L De Smit, Terneuzen, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A lighting unit according to the invention comprises a supply unit (1) and a low-pressure mercury discharge lamp (2). The low-pressure mercury discharge lamp has a light-transmitting discharge vessel (3) which is provided with a luminescent layer (3) on an inner surface and which encloses in a gastight manner a discharge space (4) which is provided with a filling comprising mercury and one or several rare gases. A first (5a) and a second electrode (5b) are arranged in the discharge space, each comprising a coiling of a metal wire coated with one or several electron-emitting metal oxides. Each electrode is electrically connected to a respective current supply conductor (6a, 6b) which extends to outside the discharge vessel (3). The current supply conductors are electrically connected to the supply unit outside the discharge vessel, the unit ignites the low-pressure mercury discharge lamp in the state upon switching-on. During nominal operation, at least a portion (5a*) of each electrode (5a, 5b) passes an electrode current Iel having an effective value Iel which is at least 1.8 times the minimum electrode current Ip4 required for thermal emission. The lighting unit according to the invention has a long switching life.