Brightness enhancement with directional wavelength conversion
US7726861B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 31, 2007 |
| Grant date | Jun 1, 2010 |
| Priority date | — |
| Expiry date | Jul 25, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133614
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An LED based illumination system with enhanced brightness is described. The system includes one or more light sources such as LEDs, one or more light couplers for efficiently collecting and collimating the light from the light sources, one or more wavelength selective filters, one or more light concentrators that focus the collimated light, and a cavity made of a layer of wavelength converting material such as a phosphorescent material located at the focus planes of the light concentrators. Each light coupler includes a light tunnel portion and a compound parabolic reflecting portion, and effectively collects and collimates light emitted by the LED in all directions. The wavelength selective filters pass the collimated light from the light sources and reflect light of a second wavelength generated by the phosphorescent material. The lights of both wavelengths exit the light cycling cavity through an aperture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.