Light degradation sensing LED signal with light pipe collector
US6717526B2 · kind B2 · utility
113Cited by
14References
50Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 6, 2001 |
| Grant date | Apr 6, 2004 |
| Priority date | — |
| Expiry date | May 7, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S362/80
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An LED signal with an LED light pipe collector and intelligent light degradation sensor. The light pipe collector captures LED light normally lost in a generally horizontal direction and redirects it into a generally vertical direction through use of total internal reflection. The light degradation sensor monitors LED signal light output. When light output degrades to a preset level, an electrical circuit triggers a disabling short circuit to deactivate the LED signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.