摘要 |
<p>An illumination system, comprising a radiation source and a luminescent material comprising at least one phosphor capable of absorbing a part of the light emitted by the radiation source and emitting light having a wavelength different from that of the absorbed light; wherein said at least one phosphor is a yellow to red-emitting europium(II)-activated ortho-phosphosilicate of general formula EA2-x-yAxPxSi1-xO4:Euy, wherein EA is at least one bivalent metal selected from the group comprising calcium, magnesium, strontium, barium, zinc and manganese, A is at least one monovalent metal chosen from the group of lithium, sodium, potassium, rubidium, cesium, copper and silver, and wherein 0.01<=x<=1 and 0.0025<=y<=0.1 can provide light sources having high luminosity and color-rendering index, especially in conjunction with a light emitting diode as a radiation source. The red to yellow emitting europium(II)-activated ortho-phosphosilicate of general formula EA2-x-yAxPxSi1-xO4:Euy, wherein EA is at least one bivalent metal selected from the group comprising calcium, magnesium, strontium, barium, zinc and manganese, A is at least one monovalent metal chosen from the group of lithium, sodium, potassium, rubidium, cesium, copper and silver, and wherein 0.01<=x<=1 and 0.0025<=y<=0.1 is efficiently excitable by primary radiation in the near UV-to-blue range of the electromagnetic spectrum.</p> |