Light wavelength conversion medium and composition for forming light wavelength conversion medium

1. A light wavelength conversion medium comprising:

a rare earth complex comprising a rare earth ion and a nonionic ligand,

a nonionic compound substitutable for said nonionic ligand, and

a polymer or a solvent,

wherein:

the total molar amount of said nonionic compound and said nonionic ligand is larger than the stoichiometric molar amount required to achieve maximum coordination of the rare earth ion contained in said light wavelength conversion medium; and

said nonionic ligand and said nonionic compound are selected from the group consisting of phosphine oxide compounds, sulfoxide compounds, and amine compounds.

2. The light wavelength conversion medium according to claim 1 , wherein said nonionic ligand and said nonionic compound have an identical structure.

3. The light wavelength conversion medium according to claim 1 , wherein said nonionic ligand and said nonionic compound have a different structure.

4. The light wavelength conversion medium according to claim 1 , wherein said nonionic ligand and said nonionic compound are represented by formula (L-1-1), (L-1-2), (L-1-3), (L-1-4), (L-2-1), (L-2-2), (L-3-1) or (L-3-2):

wherein:

each R 1 is independently a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group provided that two R 1 s connecting to a phosphorus, sulfur or nitrogen atom may be linked with each other to form an alicyclic or aromatic ring structure, and

each R 2 is a substituted or unsubstituted alkylene or a substituted or unsubstituted arylene group.

5. The light wavelength conversion medium according to claim 4 , wherein said nonionic ligand and said nonionic compound are represented by formula (L-1-1), (L-1-2), (L-1-3), or (L-1-4).

6. The light wavelength conversion medium according to claim 4 , wherein R 1 is selected from the group consisting of an alkyl group having 3 to 10 carbon atoms, a fluoroalkyl group having 3 to 10 carbon atoms, an aryl group having 5 to 20 carbon atoms, an fluoroaryl group having 5 to 20 carbon atoms, an alkylaryl group having 6 to 20 carbon atoms, an alkoxylaryl group having 6 to 20 carbon atoms, a heteroaryl group having 5 to 20 carbon atoms and a fluoroaryl group having 6 to 20 carbon atoms.

7. The light wavelength conversion medium according to claim 4 , wherein at least one R 1 is a substituted phenyl having a substituent in ortho-position.

8. The light wavelength conversion medium according to claim 1 , wherein said nonionic ligand and said nonionic compound are diphosphine dioxides.

9. The light wavelength conversion medium according to claim 1 , wherein said nonionic ligand and said nonionic compound are tetraphosphine tetra-oxides.

10. The light wavelength conversion medium according to claim 1 , wherein said rare earth ion is europium (III) ion or terbium (III) ion.

11. The light wavelength conversion medium according to claim 1 , wherein said rare earth complex comprises a ß-diketonate ligand.

12. The light wavelength conversion medium according to claim 11 , wherein said ß-diketonate ligand contains a halogenated hydrocarbon group.

13. The light wavelength conversion medium according to claim 1 , wherein said polymer is selected from the group consisting of polyacrylic acid, polymethacrylic acid, polystyrene, polycarbonate, polyester, polyolefin, polyvinyl chloride, polyvinyl acetate, and copolymers thereof.

14. The light wavelength conversion medium according to claim 1 , wherein said polymer is selected from the group consisting of polymethylmethacrylate, polycarbonate, polystyrene, acrylic resin, diethyleneglycol bisarylcarbonate, poly-4-methylpentene-1, alicyclic polyolefin resin, alicyclic acrylic resin, and copolymers thereof.

15. The light wavelength conversion medium according to claim 1 , wherein said solvent is selected from the group consisting of esters, alcohols, glycols, ketones, sulfoxides, alkanes, halogenated alkanes, and mixtures thereof.

16. The light wavelength conversion medium according to claim 1 , wherein said nonionic compound is contained in an amount of 0.01 to 100 molar equivalent based on said rare earth ion.

17. The light wavelength conversion medium according to claim 1 , wherein said rare earth ion is contained in an amount of 1×10 −7 to 1 mol/l.

18. The light wavelength conversion medium according to claim 1 , said rare earth complex is represented by the following formula (1):

wherein

each Ar is independently an aryl group,

each R is independently an alkyl group,

each R F is independently a halogenated hydrocarbon group,

n is an integer of 3 to 5,

p is an integer of 1 or 2,

q is an integer of 1 to 3,

M is a rare earth ion, and

X is absent when q is 3 but is an anion having a valence of 3-q when q is 1 or 2.

19. The light wavelength conversion medium according to claim 18 , wherein p is 1 and said light wavelength conversion medium comprises the nonionic ligand and the nonionic compound in a total amount of 1.01 to 101 equivalent based on said rare earth ion.

20. A light wavelength conversion medium-forming composition comprising:

a rare earth complex comprising a rare earth ion and a nonionic ligand,

a nonionic compound substitutable for said nonionic ligand, and

a polymer or a solvent,

wherein:

the total molar amount of said nonionic compound and said nonionic ligand is larger than the stoichiometric molar amount required to achieve maximum coordination of the rare earth ion contained in said light wavelength conversion medium; and

said nonionic ligand and said nonionic compound are selected from the group consisting of phosphine oxide compounds, sulfoxide compounds, and amine compounds.