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:
Dec. 07, 1999
Filed:
Jun. 04, 1998
Mark Fellows, New Fairfield, CT (US);
Gregory Nelson, Painted Post, NY (US);
Robertus A Keyser, Veldhoven, NL;
Dale E Work, Flemington, NJ (US);
Josephus C Hendricx, Heresveld, NL;
Oscar J Deurloo, Veldhoven, NL;
Aswin J Linden, Weert, NL;
Peter A Seinen, Veldhoven, NL;
Andrew Jackson, Hammondsport, NY (US);
Philips Electronics North America Corporation, New York, NY (US);
Abstract
A high pressure gas discharge lamp system includes a high pressure discharge lamp selected to have a lowest lamp resonant frequency above the audible, on a current basis above about 19 kHz and on a power basis of above about 38 kHz. The ballast circuit energizes the discharge device so as to have a fundamental frequency below the lowest lamp resonant frequency and above the audible, while keeping the magnitude of any harmonics above the lowest lamp resonant frequency sufficiently small so as to avoid acoustic resonance. By operating below the lowest lamp resonant frequency, greatly simplifying ballast construction and cost. According to one embodiment, the discharge vessel encloses a discharge space which is circular cylindrical and having a L:ID ratio of about 1:1 to maximize the lowest lamp resonant frequency. According to another embodiment, two or more discharge devices are operated concurrently by the ballast, each having a lowest lamp resonant frequency of above the audible, and the ballast operating frequency so as to increase light output while still avoiding acoustic resonance.