The invention relates to Eu.sup.2+-activated phosphors, to a process of its preparation, the use of these phosphors in electronic and electro optical devices, such as light emitting diodes (LEDs) and solar cells and especially to illumination units comprising said magnesium alumosilicate-based phosphors.

The present invention relates to a light emitting device comprising a red-emitting Eu.sup.3+ material and green emitting Ce.sup.3+ material which are matched so that the resulting white light has an increased lumen equivalent of radiation for a given color rendering index than with the prior art.

The present invention relates to a light emitting device comprising a red-emitting Eu.sup.3+ material and green emitting Ce.sup.3+ material which are matched so that the resulting white light has an increased lumen equivalent of radiation for a given color rendering index than with the prior art.

A lighting apparatus for emitting white light including a semiconductor light source emitting radiation with a peak emission between from about 250 nm to about 500 nm and a first phosphor having a peak emission between about 550 and 615 nm, wherein an overall emission spectrum of the lighting apparatus has a depression between about 550 and 615 nm, whereby the red-green color contrast is increased versus a reference illuminant.

Direct synthesis methods are generally provided that include reacting Na.sub.2(WO.sub.4).Math.2H.sub.2O (and/or Na.sub.2(GeO.sub.4).Math.2H.sub.2O) with NaF in an inert atmosphere at a reaction tion temperature of about 950 C. to about 1400 C., along with the resulting structures and compositions.

The present invention relates to a luminescent ink having a composition in % by weight comprising 20-55% of solvent, 5-55% of diluent; 2-15% of dispersant additive; 5-35% of solid particles with fluorescent properties, and 0.5-15% of solid dopant particles. The invention also relates to a process for obtaining a ceramic product with a printed luminescent label which incorporates a step in which digital printing is performed with said luminescent ink, this printing being applied on the surface substrate of the unfired ceramic part; and wherein the printing is performed with a digital printing machine; subjecting the ceramic part to a subsequent heat treatment in a conventional ceramic furnace at a temperature comprised between 650 and 1400 C.; and obtaining a fired ceramic product comprising a luminescent label visible with ultraviolet light. The invention also relates to a ceramic product obtainable by means of said process for obtaining a ceramic product, as well as to the use of the ink for printing luminescent labels that glow under ultraviolet light on ceramic products.