Method of making light emitting device with silicon-containing encapsulant
A method of making a light emitting device is disclosed. The method includes providing a light emitting diode and forming an encapsulant in contact with the light emitting diode; wherein forming the encapsulant includes contacting the light emitting diode with a photopolymerizable composition consisting of a silicon-containing resin and a metal-containing catalyst, wherein the silicon-containing resin consists of silicon-bonded hydrogen and aliphatic unsaturation, and applying actinic radiation having a wavelength of 700 nm or less to initiate hydrosilylation within the silicon-containing resin.
1. A method of making a light emitting device, the method comprising:
providing a light emitting diode; and
forming an encapsulant in contact with the light emitting diode, wherein forming the encapsulant comprises:
contacting the light emitting diode with a photopolymerizable composition comprising a silicon-containing resin and a metal-containing catalyst, wherein the silicon-containing resin comprises silicon-bonded hydrogen and aliphatic unsaturation; and
applying actinic radiation having a wavelength of 700 nm or less to initiate hydrosilylation within the silicon-containing resin.
2. The method of claim 1 wherein the silicon-bonded hydrogen and the aliphatic unsaturation are present in the same molecule.
3. The method of claim 1 wherein the silicon-bonded hydrogen and the aliphatic unsaturation are present in different molecules.
4. The method of claim 1 wherein at least 5 mole percent of the aliphatic unsaturation is consumed in a hydrosilylation reaction.
5. The method of claim 1 wherein at least 60 mole percent of the aliphatic unsaturation is consumed in a hydrosilylation reaction.
6. The method of claim 5 wherein the hydrosilylation reaction occurs in less than 30 minutes.
7. The method of claim 5 wherein the hydrosilylation reaction occurs in less than 10 minutes.
8. The method of claim 5 wherein the hydrosilylation reaction occurs in less than 5 minutes.
9. The method of claim 1 wherein applying actinic radiation comprises activating the light emitting diode.
10. The method of claim 1 wherein applying actinic radiation comprises applying actinic radiation at a temperature of less than 120° C.
11. The method of claim 1 wherein applying actinic radiation comprises applying actinic radiation at a temperature of less than 60° C.
12. The method of claim 1 wherein applying actinic radiation comprises applying actinic radiation at a temperature of 25° C. or less.
13. The method of claim 1 wherein the metal-containing catalyst comprises platinum.
14. The method of claim 13 wherein the metal-containing catalyst is selected from the group consisting of Pt(II) β-diketonate complexes, (η 5 -cyclopentadienyl)tri(σ-aliphatic)platinum complexes, and C 7-20 -aromatic substituted (η 5 -cyclopentadienyl)tri(σ-aliphatic)platinum complexes.
15. The method of claim 1 wherein the actinic radiation has a wavelength of 600 nm or less.
16. The method of claim 1 wherein the actinic radiation has a wavelength of from 200 to 600 nm.
17. The method of claim 1 wherein the actinic radiation has a wavelength of from 250 to 500 nm.
18. The method of claim 1 wherein the encapsulant is a liquid, gel, elastomer, or non-elastic solid.
19. The method of claim 1 wherein the encapsulant has a refractive index of at least 1.34.
20. The method of claim 1 wherein the encapsulant has a refractive index of at least 1.50.
21. The method of claim 1 wherein the photopolymerizable composition comprises an organosiloxane.
22. The method of claim 2 wherein the photopolymerizable composition comprises an organosiloxane.
23. The method of claim 1 wherein the photopolymerizable composition comprises a first organosiloxane having silicon-bonded hydrogen and a second organosiloxane having aliphatic unsaturation.
24. The method of claim 23 wherein the photopolymerizable material comprises an organosiloxane comprising units of the formula:
R 1 a R 2 b SiO (4-a-b)/2
wherein:
R 1 is a monovalent, straight-chained, branched or cyclic, unsubstituted or substituted, hydrocarbon group that is free of aliphatic unsaturation and has from 1 to 18 carbon atoms;
R 2 is a monovalent hydrocarbon group having aliphatic unsaturation and from 2 to 10 carbon atoms;
a is 0, 1, 2, or 3;
b is 0, 1, 2, or 3; and
the sum a+b is 0, 1, 2, or 3;
with the proviso that there is on average at least one R 2 present per molecule.
25. The method of claim 24 wherein at least 90 mole percent of the R 1 groups are methyl.
26. The method of claim 24 wherein at least 20 mole percent of the R 1 groups are aryl, aralkyl, alkaryl, or combinations thereof.
27. The method of claim 26 wherein the R 1 groups are phenyl.
28. The method of claim 24 wherein the R 2 groups are vinyl or 5-hexenyl.
29. The method of claim 23 wherein the photopolymerizable material comprises an organosiloxane comprising units of the formula:
R 1 a H c SiO (4-a-c)/2
wherein:
R 1 is a monovalent, straight-chained, branched or cyclic, unsubstituted or substituted, hydrocarbon group that is free of aliphatic unsaturation and has from 1 to 18 carbon atoms;
a is 0, 1, 2, or 3;
c is 0, 1, or 2; and
the sum of a+c is 0, 1, 2, or 3;
with the proviso that there is on average at least one silicon-bonded hydrogen present per molecule.
30. The method of claim 29 wherein at least 90 mole percent of the R 1 groups are methyl.
31. The method of claim 29 wherein at least 20 mole percent of the R 1 groups are aryl, aralkyl, alkaryl, or combinations thereof.
32. The method of claim 31 wherein the R 1 groups are phenyl.
33. The method of claim 1 wherein the photopolymerizable material comprises an organosiloxane comprising the formulae:
R 1 a R 2 b SiO (4-a-b)/2 and R 1 a H c SiO (4-a-c)/2
wherein:
R 1 is a monovalent, straight-chained, branched or cyclic, unsubstituted or substituted hydrocarbon group that is free of aliphatic unsaturation and has from 1 to 18 carbon atoms;
R 2 is a monovalent hydrocarbon group having aliphatic unsaturation and from 2 to 10 carbon atoms;
a is 0, 1, 2, or 3;
b is 0, 1, 2, or 3;
c is 0, 1, or 2;
the sum a+b is 0, 1, 2, or 3; and
the sum of a+c is 0, 1, 2, or 3;
with the proviso that there is on average at least one silicon-bonded hydrogen and at least one R 2 group present per molecule.
34. The method of claim 33 wherein at least 90 mole percent of the R 1 groups are methyl.
35. The method of claim 33 wherein at least 20 mole percent of the R 1 groups are aryl, aralkyl, alkaryl, or combinations thereof.
36. The method of claim 35 wherein the R 1 groups are phenyl.
37. The method of claim 33 wherein the R 2 groups are vinyl or 5-hexenyl.
38. The method of claim 1 wherein the silicon-bonded hydrogen and the aliphatic unsaturation are present in a molar ratio of from 0.5 to 10.0.
39. The method of claim 38 wherein the silicon-bonded hydrogen and the aliphatic unsaturation are present in a molar ratio of from 0.8 to 4.0.
40. The method of claim 39 wherein the silicon-bonded hydrogen and the aliphatic unsaturation are present in a molar ratio of from 1.0 to 3.0.
41. The method of claim 1 wherein the photopolymerizable material comprises one or more additives selected from the group consisting of nonabsorbing metal oxide particles, semiconductor particles, phosphors, sensitizers, antioxidants, pigments, photoinitiators, catalyst inhibitors, and combinations thereof.
42. A light emitting device prepared using the method of claim 1 .