Tri-color, white light LED lamps
US6686691B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1999 |
| Grant date | Feb 3, 2004 |
| Priority date | — |
| Expiry date | Sep 27, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to a tri-color lamp for generating white light. In particular, the invention relates to a phosphor mixture comprising two phosphors having host sulfide materials that can absorb radiation emitted by a light emitting diode, particularly a blue LED. This arrangement provides a mixing of three light sources—light emitted from the two phosphors and unabsorbed light emitted from the LED. The phosphors can contain the same dopant, such as a rare earth ion, to allow matching of the phosphors in relation to the LED emitted radiation. Power fractions of each of the light sources can be varied to achieve good color rendering. The present invention also relates to an alternative to a green LED comprising a single green phosphor that absorbs radiation from a blue LED. A resulting device provides green light of high absorption efficiency and high luminous equivalent values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.