Alkaline earth metal silicate luminophores and method for improving the long term stability thereof

US8815120B2 · kind B2 · utility

Assignee

• LEUCHTSTOFFWERK BREITUNGEN GMBH · DE

Inventors

• Wolfgang Kempfert · Bad Liebenstein, DE
• Sylke Rösler · Eisenach, DE
• Sven Rösler · Eisenach, DE
• Cheng-Jun Duan · Barchfeld-Immelborn, DE
• Rudolf Dennstedt · Barchfeld, DE

Key dates

• Filing date: Oct 14, 2010
• Grant date: Aug 26, 2014
• Expiry date: Mar 28, 2031

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2993
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

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…