Discharge lamp device having a light distribution compound lens
US6007210A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1996 |
| Grant date | Dec 28, 1999 |
| Priority date | — |
| Expiry date | Sep 12, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/388
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a discharge lamp device, the electric power supplied to a discharge lamp is controlled in order of first to fourth control regions from the start of lighting of the discharge lamp. In the first control region, the lamp current is held constant until the lamp voltage reaches a first voltage value. In the second control region, the lamp current is reduced so as to have a correlation with a first time constant curve for a constant time after the lamp voltage reaches the first voltage value. In the third control region, the lamp current is reduced so as to have a correlation with a second time constant curve after a lapse of the constant time. The second time constant curve differs from the first time constant curve. In the fourth control region, a control value of the electric power supplied to the discharge lamp is free of a function of a lapse of time from the start of lighting of the discharge lamp, but is a function of at least the lamp voltage and the lamp current, and the electric power supplied to the discharge lamp is controlled by that control value. Through such a control, luminous flux is built up in a short time from the start of the lighting and an occurrence of oversh…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.