Vehicle headlamp system and dimming-type vehicle headlamp
US7112925B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 2004 |
| Grant date | Sep 26, 2006 |
| Priority date | — |
| Expiry date | Apr 14, 2024 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60Q2300/142
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
Lamp units for radiating a beam ahead of a vehicle in a light distribution pattern are housed in a lamp body. Illumination of the auxiliary lamp units is controlled based on driving conditions. Illumination control means extinguish light through dimming by gradually decreasing voltage applied to the light sources. When the applied voltage has dropped to a threshold value, the applied voltage is controlled to zero immediately. Compared to when the lamps remaining in an illuminated state are suddenly extinguished, a change in quantity of light is mild, and no uncertainty arises. Below a threshold value where the applied voltage gradually drops to the threshold value and a change may arise in the filament crystalline structure due to annealing at a transition temperature, the applied voltage approaches zero. Hence, the filament does not pass from the transition temperature while being rapidly cooled, thus avoiding filament crystalline structure change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.