Patent application number | Description | Published |
20090256115 | COLLOIDAL DISPERSIONS OF RARE-EARTH BORATES, PREPARATION THEREOF AND LUMINOPHORES PRODUCED THEREFROM - Colloidal dispersions of rare-earth borates include a liquid phase and borate colloids dispersed therein, these colloids having a mean hydrodynamic diameter of at most 200 nm and consisting essentially of elementary particles having a mean size of less than 100 nm; such dispersions are prepared by: (a) reacting a rare-earth oxide with a controlled amount of a water-soluble monovalent acid, having a pKa of from 2.5 to 5.0; (b) heating the medium thus obtained; (c) adding boric acid to the medium obtained and heating the resulting mixture; and (d) separating the solid product from the liquid medium thus obtained, and redispersing same in a liquid phase (the subject borates are useful luminophores, especially for the manufacture of luminescent transparent materials). | 10-15-2009 |
20100051868 | LUMINOPHORES AND CORE-SHELL LUMINOPHORE PRECURSORS - A novel type of green luminophore containing mixed rare-earth phosphates is produced from precursor particles having a mean diameter ranging from 1.5 to 15 microns; such particles have an inorganic core and a shell of a mixed lanthanum and/or cerium phosphate, optionally doped with terbium, evenly covering the inorganic core with a thickness greater than or equal to 300 nm. | 03-04-2010 |
20100065780 | SUBMICRON RARE-EARTH BORATES AND PREPARATION/LUMINOSHORS THEREOF - Liquid phase suspensions of substantially monocrystalline rare-earth borate particles, the mean size thereof ranging from 100 to 400 nm, are prepared by roasting a rare earth borocarbonate or hydroxyborocarbonate at a temperature which is sufficient for forming a borate and obtaining a product whose specific surface area is equal to or greater than 3 m | 03-18-2010 |
20110068303 | SUBMICRONIC BARIUM AND MAGNESIUM ALUMINATE PHOSPHORS - Submicronic barium and magnesium aluminates, useful as phosphors, are in the form of a liquid-phase suspension of substantially monocrystalline particles having an average particle size ranging from 80 to 400 nm; such aluminates are prepared by a process that includes: providing a liquid mixture containing compounds of aluminum and of other elements that are part of the aluminate composition; drying the mixture by atomization; calcining the dried product in a reducing atmosphere and wet-grinding this product. | 03-24-2011 |
20110272632 | CERIUM AND/OR TERBIUM PHOSPHATE OPTIONALLY WITH LANTHANUM, PHOSPHOR RESULTING FROM SAID PHOSPHATE AND METHODS FOR PREPARING SAME - A rare earth (Ln) phosphate is described, wherein Ln is either: (1) at least one rare earth selected from cerium and terbium, or (2) lanthanum in combination with at least one of the two above-mentioned rare earths, and wherein the phosphate has a crystalline structure of the monazite type with a potassium content of at most 6000 ppm. The phosphate can be obtained by the precipitation of a rare earth chloride at a constant pH lower than 2, by calcination at a temperature of at least 700° C. and by redispersion in hot water. A phosphor obtained by calcination of said phosphate at at least 1000° C. is also described. | 11-10-2011 |
20110272633 | CERIUM AND/OR TERBIUM PHOSPHATE OPTIONALLY WITH LANTHANUM, PHOSPHOR RESULTING FROM SAID PHOSPHATE AND METHODS FOR PREPARING SAME - A rare earth (Ln) phosphate is described, wherein Ln is either: ( | 11-10-2011 |
20130099161 | CORE/SHELL LANTHANUM CERIUM TERBIUM PHOSPHATE, AND PHOSPHOR HAVING IMPROVED THERMAL STABILITY AND INCLUDING SAID PHOSPHATE - A phosphate particle with a mean diameter of from 1.5 μm to 15 μm, which has an inorganic core and a shell that covers the inorganic core uniformly over a thickness of no less than 300 nm, is described. The shell can have a lanthanum cerium terbium phosphate of formula La | 04-25-2013 |
20130187093 | CORE-SHELL PHOSPHOR PRODUCED BY HEAT-TREATING A PRECURSOR IN THE PRESENCE OF LITHIUM TETRABORATE - A method of producing a phosphor is described in which a precursor including particles having an average diameter from 1.5 micrometers to 15 micrometers is heat-treated under a reducing atmosphere. The method can produce particles including a mineral core and a shell including a composite phosphate of lanthanum and/or cerium, optionally doped with terbium. The composite phosphate of lanthanum and/or cerium covers the mineral core uniformly over a thickness greater than or equal to 300 nm. The aforementioned heat treatment at a temperature of 1050° C. to 1150° C. and for a time period of 2 hours to 4 hours can involve the use of lithium tetraborate (Li | 07-25-2013 |
20130313479 | COMPOSITION CONTAINING A CORE-SHELL ALUMINATE, PHOSPHOR OBTAINED FROM SAID COMPOSITION, AND PREPARATION METHODS - A composition comprising an inorganic core and an aluminate shell is described. The aluminate can have the formula (1): | 11-28-2013 |
20140048743 | LUMINOPHORES AND CORE-SHELL LUMINOPHORE PRECURSORS - A novel type of green luminophore containing mixed rare-earth phosphates is produced from precursor particles having a mean diameter ranging from 1.5 to 15 microns; such particles have an inorganic core and a shell of a mixed lanthanum and/or cerium phosphate, optionally doped with terbium, evenly covering the inorganic core with a thickness greater than or equal to 300 nm. | 02-20-2014 |
20140295153 | PHOSPHOR BASED ON A LANTHANUM CERIUM TERBIUM PHOSPHATE WITH STABILIZED BRIGHTNESS, PREPARATION PROCESS AND USE IN A LUMINESCENT DEVICE - The phosphor of the invention is based on a lanthunum cerium terbium phosphate, and it is characterized in that the phosphate consists of particles having a mean size of at most 4 μm, in that it has a lithium content of at most 30 ppm, a boton content of at most 30 ppm and in that it has a variation of brightness between the brightness measured on the phosphor at 25° C. and that measured on the same phosphor at 200° C. of at most 4%. | 10-02-2014 |