Phosphor mixture and light emitting device
US7514860B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Feb 22, 2005 |
| Grant date | Apr 7, 2009 |
| Priority date | — |
| Expiry date | Apr 20, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
To provide a light emitting device having a phosphor mixture and a light emitting part, the phosphor mixture including a red phosphor and more than one kind of phosphor having an emission spectrum with a peak in a wavelength range from 500 nm to 630 nm, and emitting light having a sufficient luminance and excellent in color rendering properties not only in a white light with high correlated color temperature, but also in a warm white light with low correlated color temperature. CaAlSiN3:Eu manufactured as a red phosphor and and CaAl2Si4N8:Eu manufactured as an orange phosphor, and for example, commercial YAG:Ce as a yellow-green phosphor, are prepared, and emission spectra of these phosphors are measured when excited by excitation light in the wavelength range from 430 nm to 500 nm. Further, the emission spectrum of the light used as an excitation light are measured, by simulation using their emission spectra, a mixing ratio of each phosphor, by which the correlated color temperature of the phosphor mixture becomes a target color temperature, is obtained. And based on the result of the simulation, each phosphor is measured and mixed, thus obtaining the phosphor mixture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.