Gregory G Nelson

US Patent:

59989394, Dec 7, 1999

Filed:

Jun 4, 1998

Appl. No.:

9/090596

Inventors:

Mark Fellows - New Fairfield CT
Gregory Nelson - Painted Post NY
Robertus A. J. Keyser - Veldhoven, NL
Dale E. Work - Flemington NJ
Josephus C. M. Hendricx - Heresveld, NL
Oscar J. Deurloo - Veldhoven, NL
Aswin J. G. Linden - Weert, NL
Peter A. Seinen - Veldhoven, NL
Andrew Jackson - Hammondsport NY

Assignee:

Philips Electronics North America Corporation - New York NY

International Classification:

H05B 3702

US Classification:

315246

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.

US Patent:

58281851, Oct 27, 1998

Filed:

May 9, 1996

Appl. No.:

8/647384

Inventors:

Mark Fellows - New Fairfield CT
Gregory Nelson - Painted Post NY
Robertus A. J. Keyser - Veldhoven, NL
Dale E. Work - Flemington NJ
Josephus C. M. Hendricx - Herersveld, NL
Oscar J. Deurloo - Veldhoven, NL
Aswin J. G. Linden - Weert, NL
Peter A. Seinen - Veldhoven, NL
Andrew Jackson - Hammondsport NY

Assignee:

Philips Electronics North America Corporation - New York NY

International Classification:

H05B 3702

US Classification:

315246

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.