Phosphor-converted white LED with low deviation of correlated color temperature and color coordinates and method of preparing the same
US9078331B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 2013 |
| Grant date | Jul 7, 2015 |
| Priority date | — |
| Expiry date | May 31, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A light emitting device is provided to produce white light with a stable correlated color temperature and stable color coordinates. The light emitting device includes a blue LED chip and a yellow phosphor. The blue LED chip has a peak wavelength X slightly smaller than the peak wavelength Y of the phosphor such that when the light emitting device is subjected to a predetermined operating current, the phosphor decays due to thermal effect, and the LED chip has its emission spectrum red-shifted to substantially match with the excitation spectrum of the phosphor. At this time, the excitation ability of the LED chip is increased and causes an increase of yellow power output from the phosphor that substantially compensates a decrease of yellow light output caused by the phosphor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.