Polarized, LED-based illumination source
US7445340B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 2005 |
| Grant date | Nov 4, 2008 |
| Priority date | — |
| Expiry date | Jul 26, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/2073
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An illumination source includes a number of light emitting diodes (LEDs) operating at a first wavelength. Light from the LEDs illuminates a phosphor material that generates light at a second wavelength. A reflective polarizer transmits light at the second wavelength in a first polarization state and reflects light at the second wavelength in a second polarization state orthogonal to the first polarization state. The light at the second wavelength reflected by the reflective polarizer is directed back towards the phosphor material without an increase in angular range. In some embodiments the LEDs, having a conformal layer of phosphor material, are attached directly to the first surface of a liquid cooled plate. A liquid coolant contacts a second surface of the plate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.