Traffic signal light having ambient light detection
US7088261B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 2004 |
| Grant date | Aug 8, 2006 |
| Priority date | — |
| Expiry date | Dec 31, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A traffic signal (310) having a reflector (322, 400) having a plurality of reflective surfaces (330, 402) directing incident ambient light received from the signal lens (318) to a photodetector (322). The reflector is disposed proximate and about a plurality of LEDs (324, 406) which are pulse width modulated by an integrated controller (360) to generate light which is also transmitted through the lens. The photodetector senses the incoming ambient light when the LEDs are in the “off” mode. Incident ambient light is focused by a lens to overfill the reflector and LEDs, and the photodetector is positioned within the redirected incident ambient light from the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.