Phosphors include a CaAlSiN.sub.3 family crystal phase, wherein the CaAlSiN.sub.3 family crystal phase comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb.

Phosphors include a CaAlSiN.sub.3 family crystal phase, wherein the CaAlSiN.sub.3 family crystal phase comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb.

Phosphors include a CaAlSiN.sub.3 family crystal phase, wherein the CaAlSiN.sub.3 family crystal phase comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb.

Provided a method for producing a nitride phosphor. The method includes preparing a mixture that comprises a first nitride and a cerium source, the first nitride comprising, as a host crystal, a crystal having the same crystal structure as CaAlSiN.sub.3; and performing a heat treatment of the mixture at a temperature of 1,300° C. to 1,900° C. to obtain a second nitride. The first nitride comprises aluminum, silicon, nitrogen, and at least one selected from the group consisting of lithium, calcium, and strontium.

Phosphors include a CaAlSiN.sub.3 family crystal phase, wherein the CaAlSiN.sub.3 family crystal phase comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb.

A phosphor powder including phosphor particles of a phosphor which is represented by a general formula M.sub.x(Si, Al).sub.2(N, O).sub.3y (where M is Li and one or more alkaline earth metal elements and 0.52x0.9 and 0.06y0.36 are satisfied) and in which a part of M is substituted with a Ce element, the phosphor powder includes phosphor particles in which a Si/Al atomic ratio is equal to or more than 1.5 and equal to or less than 6, an O/N atomic ratio is equal to or more than 0 and equal to or less than 0.1, 5 to 50 mol % of M is Li, and 0.5 to 10 mol % of M is Ce. A light absorption A.sub.700 of this phosphor powder at a wavelength of 700 nm is equal to or less than 10%.

A phosphor powder including phosphor particles which are a phosphor represented by a general formula M.sub.x(Si, Al).sub.2(N, O).sub.3y (where M is Li and one or more alkaline earth metal elements and 0.52x0.9 and 0.06y0.36 are satisfied) and in which a part of M is substituted with a Ce element, wherein a Si/Al atomic ratio is equal to or more than 1.5 and equal to or less than 6, an O/N atomic ratio is equal to or more than 0 and equal to or less than 0.1, 5 to 50 mol % of M is Li, and 0.5 to 10 mol % of M is Ce, and a total content of a Cr element, a Fe element, and a Ni element in the phosphor powder is equal to or less than 20.0 ppm.

A phosphor powder including phosphor particles of a phosphor represented by a general formula M.sub.x(Si, Al).sub.2(N, O).sub.3y and in which a part of M is substituted with a Ce element, the phosphor powder includes phosphor particles in which a Si/AI atomic ratio is equal to or more than 1.5 and equal to or less than 6, an O/N atomic ratio is equal to or more than 0 and equal to or less than 0.1, 5 to 50 mol % of M is Li, and 0.5 to 10 mol % of M is Ce. In a case where a volume-based cumulative 10% particle size, a volume-based cumulative 50% particle size, and a volume-based cumulative 90% particle size of this phosphor powder measured by a laser diffraction scattering method are defined as D.sub.10, D.sub.50, and D.sub.90, respectively, (D.sub.90-D.sub.10)/D.sub.50 is equal to or more than 0.7 and equal to or less than 1.1.

Provided is a light source device including: at least one light emitting element of at least one type; at least one far-red phosphor that, when excited by output light from the light emitting element, emits light having a peak in a wavelength range of 680 nm or more to less than 780 nm; and at least one phosphor that, when excited by the output light from the light emitting element, emits light having a peak in a wavelength range different from the wavelength range of the light emitted from the far-red phosphor. The spectrum of light emitted from the light source device has characteristic A below. This light source device has sufficient emission intensity over the entire visible range, i.e., over a wavelength range of from 400 nm to 750 nm inclusive. Characteristic A: The ratio of a minimum emission intensity to a maximum emission intensity in a wavelength range of from 400 nm to 750 nm inclusive is 20% or more.

Provided a method for producing a nitride phosphor. The method includes preparing a mixture that comprises a first nitride and a cerium source, the first nitride comprising, as a host crystal, a crystal having the same crystal structure as CaAlSiN.sub.3; and performing a heat treatment of the mixture at a temperature of 1,300? C. to 1,900? C. to obtain a second nitride. The first nitride comprises aluminum, silicon, nitrogen, and at least one selected from the group consisting of lithium, calcium, and strontium.