Phosphor, light-emitting device, illumination device, image display device, and indicator lamp for vehicle
View Patent ↗A phosphor having a favorable emission peak wavelength, narrow full width at half maximum, and/or high emission intensity is provided. Additionally, a light-emitting device, an illumination device, an image display device, and/or an indicator lamp for a vehicle having favorable color rendering, color reproducibility and/or favorable conversion efficiency are provided. The present invention relates to a phosphor including a crystal phase having a composition represented by a specific formula, and having a minimum reflectance of 20% or more in a specific wavelength region, in which the specific wavelength region is from the emission peak wavelength of the phosphor to 800 nm, and a light-emitting device comprising the phosphor.
1. An illumination device, comprising a light-emitting device as a light source,
wherein the light-emitting device comprises a first light emitter and a second light emitter that emits visible light due to irradiation with light from the first light emitter, and the second light emitter includes a phosphor that includes a crystal phase having a composition represented by formula [1] below,
Re x MA a MB b MC c N d X e [1]
wherein in formula [1] above,
MA includes one or more elements selected from the group consisting of Sr, Ca, Ba, Na, K, Y, Gd, and La,
MB includes one or more elements selected from the group consisting of Li, Mg, and Zn,
MC includes one or more elements selected from the group consisting of Al, Si, Ga, In, and Sc,
X includes one or more elements selected from the group consisting of F, Cl, Br, and I,
Re includes one or more elements selected from the group consisting of Eu, Ce, Pr, Tb, and Dy, and
a, b, c, d, e, and x satisfy the following expressions, respectively,
0.7≤a≤1.3
0.7≤b≤1.3
2.4≤c≤3.6
3.2≤d≤4.8
0.0≤e≤0.2
0.0<x≤0.2,
wherein a minimum reflectance of the phosphor in a prescribed wavelength region is 20% or more, and the prescribed wavelength region is a region from the emission peak wavelength of the phosphor to 800 nm, and
wherein the phosphor has a short emission peak wavelength of from 620 to 648 nm in an emission spectrum.
2. The illumination device according to claim 1 wherein, in formula [1], 80 mol % or more of MA is one or more elements selected from the group consisting of Sr, Ca, and Ba.
3. The illumination device according to claim 1 wherein, in formula [1], 80 mol % or more of MB is Li.
4. The illumination device according to claim 1 wherein, in formula [1], 80 mol % or more of MC is at least one selected from the group consisting of Al and Ga.
5. The illumination device according to claim 1 wherein a space group of the crystal phase having the composition represented by formula [1] is P−1.
6. The illumination device according to claim 1 wherein a full width at half maximum (FWHM) in an emission spectrum of the phosphor is 70 nm or less.
7. The illumination device according to claim 1 , further comprising a yellow phosphor and/or a green phosphor.
8. The illumination device according to claim 7 wherein the yellow phosphor and/or green phosphor include at least one phosphor selected from the group consisting of a garnet type phosphor, a silicate type phosphor, a nitride phosphor, and an oxynitride phosphor.