Patent ID: 6641448
Filing Date: 2003-11-04
Classification: C09K,H01L,H05B,Y02B

Abstract:
A method for manufacturing a white light source, the method comprising the steps of:(a) synthesizing a first phosphor powder and a second phosphor powder; (b) mixing the first phosphor powder and the second phosphor powder according to a mixing ratio into a phosphor mixture, the mixing ratio determined by the steps of: (1) measuring at a first reference wavelength an emission response of the first phosphor powder to a plurality of excitation wavelengths within a first band of excitation wavelengths; (2) selecting a first excitation wavelength from the first band of excitation wavelengths based upon the emission response measured in step (1); (3) measuring a spectral response of the first phosphor powder to the first excitation wavelength over a first band of emission wavelengths, the first band of emission wavelengths including a first emission wavelength; (4) indicating on a chromaticity chart a first color corresponding to the first emission wavelength; (5) measuring at a second reference wavelength an emission response of the second phosphor powder to a plurality of excitation wavelengths within a second band of excitation wavelengths; (6) selecting a second excitation wavelength from the second band of excitation wavelengths based upon the emission response measured in step (5); (7) measuring a spectral response of the second phosphor powder to the second excitation wavelength over a second band of emission wavelengths, the second band of emission wavelengths including a second emission wavelength; (8) indicating on a chromaticity chart a second color corresponding to the second emission wavelength; (9) drawing a line on the chromaticity chart from the indication of the first color to the indication of the second color; and (10) determining the mixing ratio of the first phosphor powder and the second phosphor powder such that an emitted color thereof lies on a line on the chromaticity chart in a region of white light; (c) providing a light source of the first excitation wavelength; and (d) applying the phosphor mixture to the light source.