Composite material for lighting filtering, lighting apparatus, and method for determining doping concentration or thickness of composite material

1. A composite material for light filtering, comprising: a polymeric matrix material and particles of neodymium compound doped in the polymeric matrix material, wherein a weight percentage of the particles of neodymium compound in the composite material is from 0.4% to 8%.

2. The composite material of claim 1 , wherein the weight percentage of the particles of neodymium compound in the composite material is from 2% to 8%.

3. The composite material of claim 2 , wherein the weight percentage of the particles of neodymium compound in the composite material is from 4% to 6%.

4. The composite material of claim 1 , further comprising: particles of additive doped in the polymeric matrix material for light diffusion.

5. The composite material of claim 4 , wherein the particles of additive doped in the polymeric matrix material comprise rutile titania TiO 2 , Al 2 O 3 , or neodymium-containing metal oxides.

6. The composite material of claim 4 , wherein the particles of additive doped in the polymeric matrix material comprise Nd-containing perovskite structure materials.

7. The composite material of claim 1 , wherein the difference of refractive indices of the polymeric matrix material and the particles of neodymium compound is less than 0.1 in the visible light region.

8. The composite material of claim 7 , wherein the source for the Nd 3 + ions are materials comprising an Nd—F compound.

9. The composite material of claim 8 , wherein the Nd—F compound comprises neodymium fluoride, neodymium oxyfluoride, neodymium fluoride comprising adventitious water and/or oxygen, a neodymium hydroxide fluoride, or other compounds containing Nd—F.

10. The composite material of claim 9 , wherein the neodymium oxyfluoride has a formula NdO x F y where 2x+y=3.

11. The composite material of claim 9 , wherein the neodymium hydroxide fluoride has a formula Nd(OH) a F b where a+b=3.

12. The composite material of claim 9 , wherein the other compounds containing Nd—F has a formula Nd—X—F where X is at least one element that forms a compound with neodymium, the at least one element selected from oxygen, nitrogen, sulfur, and chlorine or at least one metallic element, other than Nd, that forms a compound with fluorine.

13. The composite material of claim 12 , wherein the metallic element comprises Na, K, Al, Mg, Li, Ca, Sr, Ba, and Y, or combinations of such elements.

14. The composite material of claim 12 , wherein the X of the Nd—X—F compound is Mg and Ca or Mg, Ca and O.

15. The composite material of claim 1 , wherein the polymeric matrix material comprises polycarbonate, polystyrene, polyacrylate, silicone, or any combination thereof.

16. The composite material of claim 1 , wherein the particles of neodymium compound doped in the polymeric matrix material comprise Nd 3 + ions.

17. The composite material of claim 1 , wherein the polymeric matrix material comprises silicone and the particles of neodymium compound doped in the polymeric matrix material comprise NdF 3 .

18. The composite material of claim 1 , wherein the polymeric matrix material comprises polycarbonate and the particles of neodymium compound doped in the polymeric matrix material comprise NdFO.

19. The composite material of claim 1 , wherein the polymeric matrix material comprises polycarbonate and the particles of neodymium compound doped in the polymeric matrix material comprise NdF 3 .

20. The composite material of claim 1 , wherein the composite materials have different doping concentrations of the particles of neodymium compound.