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:
Jul. 25, 2000
Filed:
Oct. 30, 1998
Johannes H Wessels, Eindhoven, NL;
Johannes H Op Het Veld, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An illumination unit comprises a high-frequency supply (1) and a low-pressure discharge lamp (2). The high-frequency supply (1) is provided with a first and a second output (13a, 13b). The outputs each deliver a HF-varying voltage with respect to ground. The voltages have the same magnitude and are in phase opposition. The supply (1) is provided with a further output (13c) which is substantially free of high-frequency voltage variations with respect to ground. The low-pressure discharge lamp (2) is provided with a tubular discharge vessel (20) with an ionizable filling. The discharge vessel comprises a first and a second external electrode (23a, 23b), which are arranged at opposite ends (24a, 24b, respectively) of the discharge vessel and which are connected to the first and the second output (13a, 13b) of the supply (1) and a further external electrode (23c) which is arranged centrally between the ends (24a, 24b) of the discharge vessel (20), said external electrode being connected to the further output (13c) of the supply (1). The measure results in a more uniform brightness distribution of the discharge vessel (20).