Abstract: Provided is a method of producing a Mn-activated complex fluoride phosphor, the method including: mixing a red phosphor as a Mn-activated complex fluoride represented by the following formula (1): K2MF6:Mn??(1) wherein M is one or two or more of tetravalent elements selected from the group consisting of Si, Ti, Zr, Hf, Ge and Sn and necessarily includes Si, with K2MnF6 in solid state and optionally with a hydrogenfluoride represented by the following formula (2): AF.nHF??(2) wherein A is one or two or more of alkali metals and/or ammonium selected from the group consisting of Li, Na, K, Rb and NH4 and necessarily includes K, and n is a number of 0.7 to 4, in solid state; and heating the resulting mixture at a temperature of 100 to 500° C. According to the present invention, it is possible to obtain a Mn-activated complex fluoride phosphor which can be used with smaller amount as compared to those according to the related art.

Abstract: Provided is a method of producing a Mn-activated complex fluoride phosphor, the method including: mixing a red phosphor as a Mn-activated complex fluoride represented by the following formula (1): K2MF6:Mn??(1) wherein M is one or two or more of tetravalent elements selected from the group consisting of Si, Ti, Zr, Hf, Ge and Sn and necessarily includes Si, with K2MnF6 in solid state and optionally with a hydrogenfluoride represented by the following formula (2): AF.nHF??(2) wherein A is one or two or more of alkali metals and/or ammonium selected from the group consisting of Li, Na, K, Rb and NH4 and necessarily includes K, and n is a number of 0.7 to 4, in solid state; and heating the resulting mixture at a temperature of 100 to 500° C. According to the present invention, it is possible to obtain a Mn-activated complex fluoride phosphor which can be used with smaller amount as compared to those according to the related art.

Abstract: Disclosed is a method for the preparation of particles of a rare earth ammonium double oxalate by mixing a first aqueous solution of ammonium oxalate and a second aqueous solution of a water-soluble rare earth salt. The double oxalate particles have a polyhedral particle configuration with a uniform particle size distribution, from which a rare earth oxide powder of a polyhedral particle configuration with good flowability can be obtained by calcination, when the first and second aqueous solutions are prepared under exact control of the concentrations of the respective ionic species and the aqueous slurry containing the precipitates of the double oxalate is subjected to an aging treatment during which changes take place in the particle morphology and in the crystallographic structure of the double oxalate particles.