Provided is a method for producing a fluoride phosphor. The method includes: providing a first solution containing an element M.sup.1 containing at least one selected from the group consisting of group 13 elements, manganese, and fluorine, a second solution containing an element M.sup.2 containing at least one selected from the group consisting of group 4 elements and group 14 elements, and a third solution containing at least one selected from the group consisting of alkali metal elements; and adding the second solution and the third solution to the first solution at substantially the same time.

Provided are a liquid dispersion of fluoride particles, which has low viscosity and excellent dispersibility, and is suitable for producing an optical film such as an antireflection film; a method for producing the same; and an optical film using the same. The liquid dispersion of fluoride particles according to the present invention is that in which particles of a fluoride represented by the chemical formula A.sub.xCF.sub.y (wherein A represents sodium or potassium, C represents silicon or boron, x is 1 or 2, and y is 4 or 6) are dispersed in an aprotic organic solvent having a relative permittivity of 5 to 40, and the optical film according to the present invention is produced by using the liquid dispersion of fluoride particles.

The present disclosure discloses a method for growing a crystal in oxygen atmosphere. The method may include compensating a weight of a reactant, introducing a flowing gas, improving a volume ratio of oxygen during a cooling process, providing a heater in a temperature field, and optimizing parameters. According to the method, problems may be solved, for example, cracking and component deviation of the crystal during a crystal growth process, and without oxygen-free vacancy. The method for growing the crystal may have excellent repeatability and crystal performance consistency.

In one aspect, a process for preparing a Mn.sup.4+ doped phosphor of Formula I is provided A.sub.x[MF.sub.y]:Mn.sup.4+ (I). The process includes combining a first aqueous solution including a source of Mn with a second solution including H.sub.2MF.sub.6 to form a third solution, and combining the third solution with a fourth solution including a source of A to form the Mn.sup.4+ doped phosphor, where A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. Methods, phosphors and devices are also provided.

Provided is a method for producing an inorganic fluoride luminescent material having excellent light emission characteristics by using a non-aqueous hydrogen fluoride-containing liquid. The method for producing an inorganic fluoride luminescent material includes: bringing a first inorganic fluoride luminescent material and a non-aqueous hydrogen fluoride-containing liquid having a hydrogen fluoride content in a range of 20% by mass or more and 100% by mass or less into contact with each other to obtain a non-aqueous solution containing ions derived from the first inorganic fluoride luminescent material, and bringing the non-aqueous solution and a non-aqueous organic liquid having a hydrogen fluoride content of less than 20% by mass into contact with each other to precipitate a second inorganic fluoride luminescent material.

Provided is a method for producing an inorganic fluoride luminescent material having excellent light emission characteristics by using a non-aqueous hydrogen fluoride-containing liquid. The method for producing an inorganic fluoride luminescent material includes: bringing a first inorganic fluoride luminescent material and a non-aqueous hydrogen fluoride-containing liquid having a hydrogen fluoride content in a range of 20% by mass or more and 100% by mass or less into contact with each other to obtain a non-aqueous solution containing ions derived from the first inorganic fluoride luminescent material, and bringing the non-aqueous solution and a non-aqueous organic liquid having a hydrogen fluoride content of less than 20% by mass into contact with each other to precipitate a second inorganic fluoride luminescent material.