Encapsulated light emitting diodes and methods of making

• US 20060105483A1
• Filed: 11/18/2004
• Published: 05/18/2006
• Est. Priority Date: 11/18/2004
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Thompson, David Scott, Leatherdale, Catherine A., Kalgutkar, Rajdeep S., Boardman, Larry D.
• Application Number:
  US10/993,549
• Publication Number:
  US 20060105483A1
• Time in Patent Office: Days
• US Class Current: 438/26
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin

Abstract

Methods for making encapsulated light emitting diodes, and light emitting articles prepared thereby are disclosed. The methods include activating a light emitting diode to emit light to at least partially polymerize a photopolymerizable encapsulant.

Claims

1. A method of making a light emitting article, the method comprising:

providing an LED in a volume of a photopolymerizable encapsulant having a thickness; and

activating the light emitting diode to emit light to at least partially polymerize the entire thickness of the photopolymerizable encapsulant.

2. The method of claim 1, wherein the LED is provided in a mold, and the volume of the photopolymerizable encapsulant fills the mold.

3. The method of claim 2, wherein the mold is a reflector cup.

4. The method of claim 1, wherein the LED is provided on a substrate.

5. The method of claim 1, further comprising heating, irradiating with an external light source, or a combination thereof, to further polymerize the photopolymerizable encapsulant.

6. The method of claim 1, wherein the photopolymerizable encapsulant comprises a photoinitiator system.

7. The method of claim 6, wherein the photoinitiator system initially absorbs light of a wavelength emitted by the LED and subsequently bleaches.

8. The method of claim 1, wherein the photopolymerizable encapsulant comprises a polymerizable component and a non-polymerizable component.

9. The method of claim 8, wherein activating the LED to at least partially polymerize the photopolymerizable encapsulant provides at least partial phase separation of the polymerizable and non-polymerizable components.

10. The method of claim 8, wherein the polymerizable component is selected from the group consisting of epoxy functional materials, (meth)acrylate functional materials, organosiloxanes, and combinations thereof.

11. A method of making a light-emitting article, the method comprising:

providing an LED in a photopolymerizable encapsulant, wherein the photopolymerizable encapsulant comprises a polymerizable component and nanoparticles, and wherein the polymerizable component has a refractive index different than the refractive index of the nanoparticles; and

activating the LED to emit light to at least partially polymerize the photopolymerizable encapsulant.

12. The method of claim 11, wherein activating the LED to at least partially polymerize the photopolymerizable encapsulant allows the polymerizable component and the nanoparticles to at least partially phase separate, providing the encapsulant with a graded refractive index.

13. A method of making a light-emitting article, the method comprising:

providing an LED in a photopolymerizable encapsulant, wherein the photopolymerizable encapsulant comprises a polymerizable component and a polymer, and wherein the polymerizable component has a refractive index different than the refractive index of the polymer; and

activating the LED to emit light to at least partially polymerize the photopolymerizable encapsulant.

14. The method of claim 13, wherein activating the LED to at least partially polymerize the photopolymerizable encapsulant causes the polymerizable component and the polymer to phase separate at least partially, providing the encapsulant with a graded refractive index.

15. A method of making a light emitting article, the method comprising:

providing an LED in a photopolymerizable encapsulant wherein the photopolymerizable encapsulant comprises a polymerizable component and a non-polymerizable component, wherein the polymerizable component has a refractive index different than the refractive index of the non-polymerizable component, and wherein one of the components migrates upon polymerization of the photopolymerizable component; and

activating the LED to emit light to at least partially polymerize the photopolymerizable encapsulant.

16. The method of claim 15, wherein activating the LED to at least partially polymerize the photopolymerizable encapsulant allows the polymerizable component and the non-polymerizable component to phase separate at least partially, providing the encapsulant with a graded refractive index.

17. The method of claim 15, wherein the refractive index of the component that migrates is larger than the refractive index of the other component.

18. A method of bonding an encapsulated LED to a waveguide, the method comprising:

providing an LED in a photopolymerizable encapsulant;

contacting the waveguide with the photopolymerizable encapsulant; and

activating the LED to emit light to at least partially polymerize the photopolymerizable encapsulant.

19. A light emitting article comprising:

an LED; and

a self-aligned graded refractive index lens that substantially corresponds to the emission profile of the LED.

20. The light emitting article of claim 19 wherein the self-aligned graded refractive index lens comprises:

a polymerized component; and

nanoparticles having a refractive index different than the refractive index of the polymerized component.

21. The light emitting article of claim 19 wherein the self-aligned graded refractive index lens comprises:

a polymerized component; and

a polymer having a refractive index different than the refractive index of the polymerized component.