Abstract: The invention concerns a method for marking a material characterized in that it consists in incorporating into the material: either a phosphor capable of producing, following excitation, two light emissions whereof the respective wavelengths and the emission decay times are different, or several phosphors capable of producing, following excitation, a light emission whereof the wavelength and the emission decay time are different from the wavelength and emission decay time of the other or other phosphors. The material can in particular be of the paper, board, paint, textile, ink, glass or macromolecular material type.

Abstract: The inventive white-light emitting diode is characterized in that it comprises a source emitting radiation whose wavelength band ranges from 370 to 420 nm, a first blue and red-light emitting phosphor of formula Ba3(1-x)Eu3xMg1-yMnySi2O8 (1), wherein 0 < x 0,3 and 0 < y 0,3 and a second green-light emitting phosphor. In another embodiment, said diode comprises the same source and a single phosphor whose chemical composition is Ba3(1-x)Eu3xMg1-yMnySi2O8, wherein 0 < x 0,3 et 0 < y 0,3 and which is embodied in the form of a mixture of at least Ba2SiO4, Ba2MgSi2O7 and Ba3MgSi2O8 phases. The inventive diode can be used for a lighting device.

Abstract: The invention concerns a light transforming material, in particular for greenhouse walls, comprising as additive a barium and magnesium silicate of formula Ba3(1-x)Eu3xMg1-yMnySi2O8, wherein 0<x?0.3 and 0<y?0.3and 0<y=0.3. The material is capable of transforming solar energy of UV range into a red light. The material can also be used in paints and cosmetics.

Abstract: The inventive white-light emitting diode is characterised in that it comprises a source emitting radiation whose wavelength band ranges from 370 to 420 nm, a first blue and red-light emitting phosphor of formula Ba3(1-x)Eu3xMg1-yMnySi2O8 (1), wherein 0 < x 0,3 and 0 < y 0,3 and a second green-light emitting phosphor. In another embodiment, said diode comprises the same source and a single phosphor whose chemical composition is Ba3(1-x)Eu3xMg1-yMnySi2O8, wherein 0 < x 0,3 et 0 < y 0,3 and which is embodied in the form of a mixture of at least Ba2SiO4, Ba2MgSi2O7 and Ba3MgSi2O8 phases. The inventive diode can be used for a lighting device.

Abstract: The invention concerns a method for marking a material characterized in that it consists in incorporating into the material: either a phosphor capable of producing, following excitation, two light emissions whereof the respective wavelengths and the emission decay times are different, or several phosphors capable of producing, following excitation, a light emission whereof the wavelength and the emission decay time are different from the wavelength and emission decay time of the other or other phosphors. The material can in particular be of the paper, board, paint, textile, ink, glass or macromolecular material type.

Abstract: The invention concerns a light transforming material, in particular for greenhouse walls, comprising as additive a barium and magnesium silicate of formula Ba; 3(1-x)Eu; 3xMg; 1-yMn; ySi; 2O; (1), wherein 0<x=0.3 and 0<y=0.3. Said material is capable of transforming solar energy of UV range into a red light. Said material can also be used in paints and cosmetics.

Abstract: The present invention relates to the use of a compound based on a thulium-containing lanthanum phosphate as a phosphor in a plasma or X-ray system. This phosphate may furthermore contain gadolinium. The thulium content of the compound, expressed in at % with respect to the lanthanum, is between 0.1 and 10, more particularly between 0.5 and 5. The invention also covers a lanthanum phosphate which is characterized in that it contains thulium and in that it consists of particles having a mean size of between 1 and 20 &mgr;m with a dispersion index of less than 0.6.

Abstract: Novel pigmentary colorants, well adapted for the production of electrostatic developer powders, are comprised of mineral core particulates, at least one mineral oxide and at least one dye, said at least one mineral oxide being deposited onto the surface area of the core particulates, and said at least one dye being absorbed onto the core particulates or onto the at least one mineral oxide and/or being at least partly physically confined within a matrix of the mineral oxide.

Abstract: The invention relates to new diazotype materials of which the sensitive layer contains, as a base generator, a compound comprising a basic part and an acid part, the acid part being a 2-carboxycarboxamide group and the basic part consisting of an alkali metal cation or alkaline earth metal cation or a tetraalkylammonium cation.These diazotype materials develop rapidly and possess an excellent resistance to ageing.

Abstract: Phenylurethane compounds formed by the reaction between a phenolic coupler compound and an organic isocyanate compound are utilized to form phenolic coupler compounds in situ in order to react with chromogenic compounds present in the sensitive layer of recording or reproducing materials.The phenolic coupler compounds can also be stabilized by blocking the phenolic hydroxyl with carbonate, an alkyl ether, organosilylated ether or organophosphoric acid ester, some of which are novel compounds. These stabilized derivatives of the stabilized phenolic coupler compound will decompose by application to sufficient thermal energy or suitable liquid or gaseous fluid to form the phenolic coupler compound in situ. The phenolic coupler compound is formed in situ by applying thermal energy to the sensitive layer or by applying to the sensitive layer a liquid or gaseous fluid which is able to decompose the stabilized phenolic coupler compound and release the phenolic coupler compound.

Abstract: A tamperproof identification card such as a passport or credit card is provided. A diazo photosensitive composition is intimately mixed with a thermo-adhesive resin and is carefully deposited as a uniformly thin layer in one or more zones on a plastic support material. The zones of the photosensitive compositions are developed to reproduce identifying information such as a photograph, identification number, etc. A plastic protective film is then laminated to the support to protect the identifying information. Since the adhesive resin material is intimately mixed throughout the photosensitive composition, the protective plastic film cannot be removed without destroying the information.

Abstract: A writing liquid is formed from a solvent for an organic styrene resin pigment in combination with a chlorofluoroalkane of from 1 to 3 carbon atoms. The potential toxicity of the solvent (or solvent vapors) is eliminated and writing speeds of the writing liquid are improved by the addition of the chlorofluoroalkane. The writing liquid is used for transparentizing an opaque layer of an organic styrene resin pigment, uniformly distributed as fine particles in a film-forming binder carried on a transparent or opaque support. When the writing liquid is applied to the opaque layer using a suitable writing instrument, such as a pen, the opaque layer immediately becomes transparent where it is contacted with the solvent.

Abstract: An opaque recording material has an opaque sensitive layer which can be transparentized by application of heat or a suitable solvent for the opacifying styrene resin pigment which is dispersed in a polyvinylidene chloride film-forming resin binder. In a particular application, useful for overhead transparencies or for making photographic negatives for reproduction, heat and solvent are both applied to the opaque layer in selected different areas to transparentize the opaque layer. The opaque layer may be deposited on a transparent clear or colored support such as transparent polyester.

Abstract: Transparencies for overhead projection are formed in which the information to be displayed is in the form of transparent lines, or other geometric patterns, on an opaque background. The transparent lines are formed on an opaque layer of a recording material formed from a clear or colored transparency on which the opaque layer is firmly adhered. The opaque layer is formed from finely divided organic styrene resin pigment uniformly distributed in a film-forming binder resin. The writing liquid is formed from a solvent for the organic styrene resin pigment. When the writing liquid is applied to the opaque layer using a suitable writing instrument, such as a pen, the opaque layer immediately becomes transparent where it is contacted with the solvent. The potential toxicity of the solvent (or solvent vapors) is eliminated and writing speeds may be increased by mixing a chlorofluoroalkane of from 1 to 3 carbon atoms with the solvent.

Abstract: The photochromic activity of triphenylmethane paraamino leuco salts is reversibly inactivated in compositions containing the leuco salt with certain metallic oxides or sulfides. The photochromic properties of the leuco salts are restored by the application of energy, e.g. heat, mechanical pressure, etc. The sensitive compositions containing the leuco salt and metal oxide or sulfide are useful in a process for recording information according to a predetermined pattern by applying a local heat source or local pressure source to a recording material containing a layer of the sensitive composition, the application of energy resulting in the formation of colored marks corresponding to the information to be recorded.