Light emitting diode assembly and method of fabrication

• US 20080111141A1
• Filed: 05/07/2007
• Published: 05/15/2008
• Est. Priority Date: 11/09/2006
• Status: Active Grant

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Dong, Yi, Li, Yi-Qun, Shan, Wei
• Granted Patent: US 7,737,636 B2
• Time in Patent Office: Days
• US Class Current: 257/88
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

An LED assembly comprises an LED and a lens disposed adjacent to a light emitting surface of the LED. The area of cross-section of the lens projected onto the light emitting surface of the LED is substantially equal to or less than the area of the LED'"'"'s light emitting surface. The light emitting device can comprise an array of LEDs and an array of lenses, in which at least one lens is associated with each member of the LED array and wherein the area of a cross-section of each lens projected onto the light emitting surface of its associated LED is substantially equal to or less than the area of the LED'"'"'s light emitting surface.

Claims

1. An LED assembly comprising:

an LED and a lens disposed adjacent to a light emitting surface of the LED;

wherein the area of a cross-section of the lens projected onto the light emitting surface of the LED is substantially equal to or less than the area of the LED'"'"'s light emitting surface.

2. The LED assembly of claim 1, and further comprising a phosphor encapsulated within a transparent material, the transparent material surrounding at least a portion of the light emitting surface of the LED.

3. The LED assembly of claim 1, and further comprising a phosphor layer disposed between the lens and at least a portion of the LED'"'"'s light emitting surface.

4. An LED assembly comprising:

at least two lenses disposed adjacent to a light emitting surface of an LED;

wherein the sum of the areas of the cross-sections of the at least two lenses projected onto the light emitting surface of the LED is substantially equal to or less than the area of the LED'"'"'s light emitting surface.

5. The LED assembly of claim 4, and further comprising a phosphor encapsulated within a transparent material, the transparent material surrounding at least a portion of the light emitting surface of the LED.

6. The LED assembly of claim 4, and further comprising a phosphor layer disposed between the at least two lenses and at least a portion of the LED'"'"'s light emitting surface.

7. A light emitting device comprising:

an array of LEDs and an array of lenses, wherein there is at least one lens associated with each member of the LED array and wherein the area of a cross-section of each lens projected onto the light emitting surface of the its associated LED is substantially equal to or less than the area of the LED'"'"'s light emitting surface.

8. The light emitting device of claim 7, and further comprising a phosphor encapsulated within a transparent material, the transparent material surrounding at least a portion of the lens array.

9. The light emitting device of claim 7, and further comprising a phosphor layer disposed between at least one of the lenses of the lens array and at least one of the LEDs of the LED array.

10. A photonic device comprising:

an LED configured to emit radiation at a first wavelength from a light emitting surface;

a lens configured to optically focus radiation from the LED;

a phosphor positioned adjacent to the LED, the phosphor configured to absorb at least a portion of the radiation emitted by the LED and emit radiation at a second wavelength, wherein the area of a cross-section of the lens projected onto the light emitting surface of the LED is substantially equal to or less than the area of the LED'"'"'s light emitting surface.

11. The photonic device of claim 10, wherein the phosphor is encapsulated within a transparent material, the transparent material surrounding at least a portion of a light emitting surface of the LED.

12. The photonic device of claim 11, wherein the phosphor is disposed as a layer between the lens and at least a portion of the LED'"'"'s light emitting surface.

13. A method of fabricating an LED assembly, the method comprising:

a) dispensing a transparent lens material onto a substrate containing an LED array; and

b) molding the transparent lens material into a desired pattern of lenses to match the pattern of the LED array.

14. The method of claim 13, and further comprising a step of curing the transparent lens material, the step selected from the group consisting of a UV curing step and a thermal heat curing step.

15. The method of claim 13, and further comprising removing selected regions of the transparent lens material to provide electrical access to electrodes of the LED array.

16. The method of claim 15, and comprising removing the selected regions of the transparent lens material by the process selected from the group consisting of:

etching, an oxygen plasma etching and wet etching.

17. The method of claim 13, and further comprising depositing a phosphor layer over substantially the entire surface of the LED array substrate prior the dispensing the transparent lens material on the LED array substrate.

18. The method of claim 17, and further comprising providing a release agent overlying electrode regions of the LED array prior to depositing the phosphor.

19. The method of claim 18, and further comprising processing the release agent and using a lift-off process to remove selected regions of the phosphor layer and transparent lens material to provide electrical access to electrode regions of the LED array.

20. The method of claim 13, and further comprising further comprising embedding the molded lens material and LED array into a transparent matrix containing a phosphor.