Luminous flux depreciation notification system for light fixtures incorporating light emitting diode sources
US8111388B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 4, 2010 |
| Grant date | Feb 7, 2012 |
| Priority date | — |
| Expiry date | Aug 11, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2001/4252
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A LED light fixture and a luminous flux monitoring system for a light fixture. The light fixture includes a housing defining an interior space including an interior surface and a transmissive panel. A light source is coupled to the interior surface. The system includes a light sensor coupled to the interior surface and aligned to receive light from the transmissive panel, light source, and/or interior surface. The light sensor is configured to measure luminous flux in the interior space. A controller is coupled to the light source and the light sensor. The controller is configured to determine if a light sensor measurement of luminous flux in the interior space is more or less than a reference value of the luminous flux. If the measurement of luminous flux is less than the reference value, the controller is configured to activate an end-of-life indicator. The reference value equals (total flux−internal ambient flux)×depreciation factor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.