Rare earth phosphate particles, method for improving light scattering using same, and light scattering member and optical device including same
A rare earth phosphate particle containing a rare earth element A, where A is Sc, Y, La, Eu, Gd, Dy, Yb, or Lu, and a rare earth element B different from the element A, where B is Sc, Y, La, Eu, Gd, Dy, Yb, or Lu. The phosphate of the element A is preferably crystalline, with at least part of the element B dissolved in the phosphate of the element A in a solid state. The phosphate of the element A preferably has a xenotime or monazite crystal structure.
1. Rare earth phosphate particles comprising:
a rare earth element A; and
a rare earth element B different from the element A,
wherein the element A is Sc, Y, La, Gd, or Lu,
the element B is Sc, Y, La, Gd, or Lu,
the phosphate of the element A is crystalline, and
at least part of the element B is dissolved in the phosphate of the element A in a solid state.
2. The rare earth phosphate particles according to claim 1 , wherein the phosphate of the element A has a xenotime or monazite structure.
3. The rare earth phosphate particles according to claim 2 , having an XRD pattern wherein the position (2θ) of a peak with the maximum intensity shifts to a lower or higher angle by 0.01° to 0.70° from a reference position of a peak with the maximum intensity of a phosphate of only the element A.
4. The rare earth phosphate particles according to claim 3 , wherein
the element A is Y, Gd, or Lu, and
the element B is Y, Gd, or Lu.
5. The rare earth phosphate particles according to claim 2 , wherein
the element B is Y, Gd, or Lu.
6. The rare earth phosphate particles according to claim 2 , wherein
the element A is Y, Gd, or Lu, and
the element B is Y, Gd, or Lu.
7. The rare earth phosphate particles according to claim 1 , wherein the element B is present in an amount of 0.1 to 50 mol % based on the total number of moles of the elements A and B.
8. The rare earth phosphate particles according to claim 1 , wherein the element A is Y, Gd, or La.
9. The rare earth phosphate particles according to claim 8 , wherein
the element B is Y, Gd, or Lu.
10. The rare earth phosphate particles according to claim 1 , being placed inside or on a surface of a substrate to cause light scattering.
11. The rare earth phosphate particles according to claim 1 , wherein
the element B is Y, Gd, or Lu.
12. The rare earth phosphate particles according to claim 1 , wherein
the element A is Y, Gd, or Lu, and
the element B is Y, Gd, or Lu.
13. A method for improving light-scattering properties of a substrate, comprising:
incorporating the rare earth phosphate particles according to claim 1 into the substrate.
14. A method for improving light-scattering properties of a substrate, comprising:
placing the rare earth phosphate particles according to claim 1 on the surface of the substrate.
15. A dispersion comprising:
the rare earth phosphate particles according to claim 1 and an organic solvent.
16. A resin composition comprising:
the rare earth phosphate particles according to claim 1 and a resin.
17. A light-diffusing element comprising:
the resin composition according to claim 16 .
18. An optical device comprising the light-diffusing element according to claim 17 .
19. A light-diffusing element, having a light-diffusing layer, the light-diffusing layer comprising:
the resin composition according to claim 16 and having a thickness T (μm) and a rare earth phosphate particle concentration C (mass %), the T and C satisfying relation (I):
5≤( T×C )≤500 (I).
20. An optical device comprising the light-diffusing element according to claim 19 .