High frequency HID lamp system
US5998939A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1998 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Jun 4, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/2988
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.