Patent ID: 8491154
Filing Date: 2013-07-23
Classification: G02F,H01L

Abstract:
1. An illumination system comprising: a semiconductor light-emitting device configured to emit light of a first color, the semiconductor device comprising a first luminescent layer configured to absorb part of the light of the first color and to pass part of the light of the first color, the absorbed part of the light of the first color exciting the first luminescent layer causing emission of light of a second color; and a second luminescent layer separated from the semiconductor light-emitting device by the first luminescent layer and configured to absorb part of the light of the first color and to pass part of the light of the first color and part of the light of the second color, the absorbed part of the light of the first color exciting the second luminescent layer causing emission of light of a third color, the second luminescent layer being formed of the same material as the first luminescent layer and having a thickness different from a thickness of the first luminescent layer, wherein the illumination system is configured to combine light of the first, second and third colors to form output light of the illumination system, the thickness of the second luminescent layer being selected for correcting a color point of the output light to attain a desired target point of the output light, and wherein the first luminescent layer is configured to provide a greater degree of light conversion than the second luminescent layer, the degree of light conversion being measurable by the shift in color point on a 1976 CIE chromaticity diagram away from the color point of the color.