Method and system for driving a plasma-based light source
US7514879B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 24, 2004 |
| Grant date | Apr 7, 2009 |
| Priority date | — |
| Expiry date | Jan 11, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/2821
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A gas discharge lamp is driven with a constant current square wave from a current transformer where the number of volt-microseconds are designed such that at the start of each square wave, the voltage rises to the required ionization potential for the lamp, while the plasma has not yet started to conduct. As soon as the lamp ionizes the gas within the lamp and current flows, the voltage drops and current flows at the desired level. The current level is set to prevent the input of excessive power pulses into the lamp, to reduce the creation of infrared photons. In addition, the plasma is driven at this current level almost continuously (with reversing polarity), which does not allow the plasma time to cool down. Consequently, the lamp becomes a more efficient light emitter, thereby requiring less energy to achieve the same light output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.