Method of making a light emitting device having a molded encapsulant
Disclosed herein is a method of making a light emitting device having an LED die and a molded encapsulant made by polymerizing at least two polymerizable compositions. The method includes: (a) providing an LED package having an LED die disposed in a reflecting cup, the reflecting cup filled with a first polymerizable composition such that the LED die is encapsulated; (b) providing a mold having a cavity filled with a second polymerizable composition; (c) contacting the first and second polymerizable compositions; (d) polymerizing the first and second polymerizable compositions to form first and second polymerized compositions, respectively, wherein the first and second polymerized compositions are bonded together; and (e) optionally separating the mold from the second polymerized composition. Light emitting devices prepared according to the method are also described.
1. A method of making a light emitting device, the method comprising:
(a) providing an LED package comprising an LED die disposed in a reflecting cup, the reflecting cup filled with a first photopolymerizable composition such that the LED die is encapsulated, and partially polymerizing the first photopolymerizable composition to form a first partially photopolymerized composition, wherein partially polymerizing comprises applying actinic radiation having a wavelength of 700 nm or less;
(b) providing a mold having a cavity filled with a second polymerizable composition;
(c) contacting the first partially photopolymerized composition and the second polymerizable composition;
(d) polymerizing the first partially photopolymerized composition and the second polymerizable composition to form first and second polymerized compositions, respectively, wherein the first and second polymerized compositions are bonded together; and
(e) optionally separating the mold from the second polymerized composition.
2. The method of claim 1 , wherein contacting the first partially photopolymerized composition and the second polymerizable composition comprises inverting the LED package.
3. The method of claim 1 , wherein contacting the first partially photopolymerized composition and the second polymerizable compositions comprises inverting the mold.
4. The method of claim 1 , wherein the second polymerizable composition comprises a second partially polymerized composition.
5. The method of claim 1 , wherein the first photopolymerizable composition and/or the second polymerizable compositions are thixotropic.
6. The method of claim 1 , wherein the first photopolymerizable composition comprises a resin selected from the group consisting of silicon-containing resins comprising silicon-bonded hydrogen and aliphatic unsaturation, epoxy silicones, and (meth)acrylated silicones.
7. The method of claim 1 , wherein the second polymerizable composition comprises a resin selected from the group consisting of silicon-containing resins comprising silicon-bonded hydrogen and aliphatic unsaturation, epoxy silicones, and (meth)acrylated silicones.
8. The method of claim 1 , wherein the second polymerizable composition comprises a multi-functional (meth)acrylate.
9. The method of claim 1 , wherein the first photopolymerizable composition and the second polymerizable compositions are the same.
10. The method of claim 1 , wherein the second polymerized composition is harder than the first.
11. The method of claim 1 , wherein the first polymerized composition has a refractive index greater than that of the second.
12. The method of claim 1 , wherein the second polymerized composition is harder than the first, and the first polymerized composition has a refractive index greater than that of the second.
13. The method of claim 1 , wherein the first photopolymerizable composition comprises two layers having the same or different composition.
14. The method of claim 1 , wherein the second polymerizable composition comprises two layers having the same or different composition.
15. The method of claim 1 , the mold comprising a mold material and being shaped to impart a positive or negative lens on a substantial portion of the surface of the second polymerizable composition.
16. The method of claim 1 , the mold comprising a mold material and being shaped to impart macrostructures, each macrostructure having a dimension of from 10 um to 1 mm.
17. The method of claim 1 , the mold comprising a mold material and being shaped to impart microstructures, each microstructure having a dimension of from 100 nm to less than 10 um.
18. The method of claim 1 , wherein polymerizing the first partially photopolymerized composition and the second polymerizable composition comprises applying actinic radiation having a wavelength of 700 nm or less.
19. The method of claim 1 , wherein polymerizing the first partially photopolymerized composition and the second polymerizable composition comprises simultaneously applying actinic radiation having a wavelength of 700 nm or less and heating at less than 150° C.
20. The method of claim 1 , comprising separating the mold from the second polymerized composition to form a molded second polymerized composition, and the method further comprising heating the molded second polymerized composition at less than 150° C.
21. The method of claim 1 , the LED die comprising a plurality of LED dice.
22. The method of claim 21 , wherein each LED die of the LED dice emits light of substantially the same wavelength.
23. The method of claim 21 , wherein the LED dice emit light of different wavelengths.
24. The method of claim 1 , wherein providing an LED package comprising an LED die disposed in a reflecting cup comprises providing a plurality of LED packages disposed on a lead frame, each LED package comprising an LED die disposed in a reflecting cup.