| 摘要 |
The present invention relates to alkaline earth metal silicate luminophores having improved long-term stability and to a corresponding method for improving the long-term stability of alkaline earth metal silicate luminophores. The luminophore according to the invention is a luminophore comprising a base lattice according to the general chemical formula EAxSiyOz, where x, y, z>0. The component EA is formed by one or more alkaline earth metals. An activator, for example Eu2+ or Mn2+, is doped into the base lattice. The luminophore has the fundamental property to absorb radiation in a first wavelength range and emit radiation in a second wavelength range that is different from the first wavelength range. The luminophore is designed in the form of crystals. According to the invention, the surfaces of the crystals of the luminophore are chemically modified such that at least portions of the surfaces thereof are formed by a chemical compound of the general formula EauZ2. The component Z is formed by anions, which can be chemically combined with the EA cations of the luminophore. The variable u is equal to an ion charge of the anions Z. The chemical modification is therefore not a coating. |
| 主权项 |
1. A luminophore having an improved long-term stability, which absorbs radiation in a first wavelength range, and emits radiation in a second wavelength range that is different from the first wavelength range, wherein the luminophore is designed in the form of grains, and comprises an alkaline earth metal silicate of the general chemical formula EAxSiyOz as a base lattice, which is doped with an activator, wherein EA is formed by one or more alkaline earth metals, and the condition x, y, z>0 applies, wherein said base lattice is described by one of the following chemical formulas:
(BaaSrbCac)2SiO4, wherein at least one of the variables a, b and c is greater than zero, and a+b+c=1; EA′3MgSi2O8, EA′2MgSi2O7, EA′2MgSiO5, where EA′ is formed by one or more alkaline earth metals excluding magnesium; and EA3SiO5,and wherein the grains are chemically modified on their surface such that at least portions of their surface are formed by a chemical compound of the general formula EAuZ2, wherein the general formula can be represented by a formula in which the coefficients are mathematically abbreviated if the variable u is even; and wherein Z is formed by anions which can be chemically combined with cations of EA, and which are described by one or more of the following chemical formulas: SO42−, PO43−, CO32−, C2O42−, SiO32−, and SiF62−; wherein u is equal to an ion charge of the anions Z. |
