A value document system, a method for identifying a value document of a value document system, and a luminescent substance set, wherein the value document system includes at least a first value document and a second value document. The first value document has a security feature composed of a combination of at least a first and a second luminescent substance of a first or a second substance class. The second value document has a security feature with at least a first luminescent substance of the first or second substance class. The security feature of the first value document has at least a different intensity ratio of the emission, a different decay time ratio and/or a different decay time sum in two adjacent spectral ranges compared with the security feature of the second value document.

A UV excitation light source comprises a phosphor. The phosphor contains Sc.sub.xY.sub.1-xPO.sub.4 crystals (wherein 0<x<1), and, upon receiving UV light of a first wavelength, generates UV light of a second wavelength that is longer than the first wavelength. A method for producing the phosphor includes: a first step for producing a mixture that includes an oxide of Y, an oxide of Sc, phosphoric acid, and a liquid; a second step for vaporizing the liquid; and a third step for baking the mixture.

There is provided a paint including a pigment, a carrier liquid, a binder, one or more additives, and a taggant corresponding to the one or more additives. The taggant is provided in an amount up to substantially 0.1% by weight of the paint. The taggant is excitable by infra-red or UV light at one wavelength to emit light at one or more other wavelengths, the emission wavelength or spectrum of the taggant being indicative of the additive(s) in the paint. A method of authenticating the paint on a substrate is also provided.

An ultraviolet light generation target includes a light emitting layer. The light emitting layer contains a YPO.sub.4 crystal to which at least scandium (Sc) is added, and receives an electron beam to generate ultraviolet light. Further, a method of manufacturing the ultraviolet light generation target includes a first step of preparing a mixture containing yttrium (Y) oxide, Sc oxide, phosphoric acid, and a liquid, a second step of evaporating the liquid, and a third step of firing the mixture.

The invention relates to a converter system, for instance for a light emitting device, comprising: —a first material, which comprises, preferably essentially consists of an emitting material, emitting a color of interest, and is essentially free of sensitizer material, —a second sensitizer material, which is essentially free of the first material and absorbs light (is excitable) in the wavelength range of interest and its emission spectrum overlaps at least partly with one or more excitation bands of the first material.

The invention provides Y.sub.2O.sub.3:RE nanoparticles having a cubic crystal structure, wherein RE is a trivalent rare earth metal ion. The invention further provides a method of preparing Y.sub.2O.sub.3:RE nanoparticles, comprising: a) providing a mixture comprising (i) an yttrium salt and/or yttrium alkoxide, (ii) a rare earth metal salt and/or rare earth metal alkoxide, and (iii) an organic solvent; b) optionally, subjecting the mixture to a pre-treatment step which comprises heating the mixture at a temperature of at least 80° C. and/or at a temperature such that crystal water and/or organic impurities are removed, c) heating the mixture at a temperature between 220° C. and 320° C. and/or at a temperature such that a precursor complex forms; d) subjecting the mixture to a precipitation stage, wherein a precipitate forms, said precipitation stage preferably comprising allowing the mixture to cool and/or adding an antisolvent to the mixture; and e) heating the precipitate at a temperature between 600° C. and 900° C. and/or at a temperature such that a cubic Y.sub.2O.sub.3 crystal structure forms, preferably for at least 10 minutes.

The manufacturing method is a method for manufacturing a light emitter that generates ultraviolet light. The light emitter contains a YPO.sub.4 crystal to which at least scandium (Sc) is added, and receives an electron beam or excitation light having a shorter wavelength than a wavelength of the ultraviolet light, to generate the ultraviolet light. The manufacturing method includes: producing a first mixture; producing a second mixture; producing a third mixture; and sintering the third mixture. The first mixture containing a compound of yttrium (Y), a compound of scandium (Sc), phosphoric acid or a phosphate compound, and a liquid is produced. In the producing the second mixture, the second mixture in a powder form is produced by evaporating the liquid. In the producing the third mixture, the third mixture is produced by mixing either one or both of an alkali metal halide and an alkali metal carbonate with the second mixture.

A light fixture includes a first phosphor-converted light-emitting diode (“PCLED”) emitting light in a first PCLED wavelength range having first PCLED upper and lower bounds, a first direct light-emitting diode (“DLED”) emitting light in a first DLED wavelength range having first DLED upper and lower bounds, a second PCLED emitting light in a second PCLED wavelength range having second PCLED upper and lower bounds, and a second DLED emitting light in a second DLED wavelength range having second DLED upper and lower bounds. The first PCLED upper bound has a higher wavelength value than the first DLED upper bound. The first PCLED lower bound has a lower wavelength value than the first DLED lower bound. The second PCLED upper bound has a higher wavelength value than the second DLED upper bound. The second PCLED lower bound has a lower wavelength value than the second DLED lower bound.

An optical storage phosphor, a method for checking an authenticity feature, and an apparatus for carrying out a method, relate to an authenticity feature and to a value document. An inorganic optical storage phosphor is provided having a garnet structure and predetermined composition.

Examples of a monolithic phosphor composite for measuring a parameter of an object are disclosed. The ceramic metal oxide phosphor composite is used in an optical device for measuring the parameter of the measuring object. The device comprises a fiber optic probe with a light guide, a light source operatively coupled to the fiber optic probe to provide excitation light into the light guide, a monolithic ceramic metal oxide phosphor composite functionally coupled to a tip of the fiber optic probe, a sensor operatively coupled to the fiber optic probe to detect the emitted light and a processing unit functionally coupled to the sensor to process the emitted light. The monolithic ceramic metal oxide phosphor composite can be embedded in a notch made into the object or can be adhered to a surface of the object with a binder. When the monolithic ceramic metal oxide phosphor composite is illuminated with the excitation light it emits light in a wavelength different from the excitation light and a change in emission intensity at a single wavelength or the change in intensity ratio of two or more wavelengths, a shift in emission wavelength peak or a decay time of the phosphor luminescence is a function of the measuring parameter.