Conformally coated light emitting devices and methods for providing the same

• US 9,166,126 B2
• Filed: 01/31/2011
• Issued: 10/20/2015
• Est. Priority Date: 01/31/2011
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Donofrio, Matthew, Nordby, Howard, Andrews, Peter S.
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US13/017,845
• Publication Number:
  US 20120193648A1
• Time in Patent Office: 1,723 Days
• Field of Search: 257/98
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

Methods are disclosed including applying a conformal coating to multiple light emitters. The conformal coating forms in gap areas between adjacent ones of the light emitters. The plurality of light emitters are separated into individual light emitters. The individual light emitters include the conformal coating that extends to a space corresponding to respective gap areas. Light emitting structures are disclosed including a semiconductor light emitting diode (LED) having an active region and a conformal coating including a first portion and a second portion, the first portion corresponding to at least one surface of the LED and the second portion extending from the first portion.

Claims

1. A light emitting structure, comprising:

a semiconductor light emitting diode (LED) comprising an active region; and

a conformal phosphor coating comprising a first portion and a second portion, the first portion corresponding to at least one surface of the LED and the second portion extending from the first portion to form a conformal phosphor wing arranged around an edge of the LED, wherein the conformal phosphor wing coating includes a thickness in a range of about 30 μ

m to about 100 μ

m;

wherein the conformal phosphor coating comprises a first conformal coating that is applied to the LED and a second conformal coating that is applied to the first conformal coating.

2. The light emitting structure according to claim 1,

wherein the LED includes a first surface, at least one side surface, and a second surface that is substantially opposite the first surface, and

wherein the conformal phosphor wing includes at least one surface that is substantially parallel to the second surface.

3. The light emitting structure according to claim 1, wherein the LED comprises a transitional surface that defines a transition between the first surface and the at least one side surface.

4. The light emitting structure of claim 1,

wherein the first and second conformal coatings each comprise light conversion particles that are configured to convert a portion of light received from the LED.

5. The light emitting structure according to claim 1,

wherein the first conformal coating comprises first light conversion particles having first light conversion properties, and

wherein the second conformal coating comprises second light conversion particles having second light conversion properties that are different from the first light conversion properties.

6. A light emitting structure, comprising:

a semiconductor light emitting diode (LED) comprising an active region; and

a conformal coating comprising a first portion and a second portion, the first portion corresponding to at least one surface of the LED and the second portion extending from the first portion to form a conformal coating ledge,

wherein the second portion of the conformal coating includes a thickness in a range of about 30 μ

m to about 100 μ

m;

wherein the LED comprises a conductive portion on a first surface of the LED.

7. The light emitting structure according to claim 6, wherein the conformal coating ledge is substantially circumferential around the LED.

8. The light emitting structure according to claim 6,

wherein the LED includes at least one side surface, and a second surface that is substantially opposite the first surface,

wherein the conformal coating includes a first side and a second side that is opposite the first side;

wherein the first side of the first portion of the conformal coating is adjacent the first surface and the at least one side surface.

9. The light emitting structure according to claim 8, wherein the first side corresponding to the second portion of the conformal coating is substantially parallel to the second surface of the LED.

10. The light emitting structure according to claim 8,

wherein the conductive portion is free of the conformal coating.

11. The light emitting structure according to claim 10, wherein the conductive portion comprises at least one of a solder bump bond and a wirebond conductor.

12. The light emitting structure according to claim 8, wherein the LED comprises a transitional surface that defines a transition between the first surface and the at least one side surface.

13. The light emitting structure according to claim 6,

wherein the LED is one of a plurality of LEDs, and

wherein the second portion of the conformal coating corresponds to conformal coating that was formed in at least one gap between adjacent conformally coated ones of the plurality of LEDs.

14. The light emitting structure according to claim 6,

wherein the conformal coating comprises a first conformal coating that is applied to the LED and a second conformal coating that is applied to the first conformal coating, and

wherein the first and second conformal coatings each comprise light conversion particles that are configured to convert a portion of light received from the LED.

15. The light emitting structure according to claim 6,

wherein the conformal coating comprises a first conformal coating that is applied to the LED and a second conformal coating that is applied to the first conformal coating,

wherein the first conformal coating comprises first light conversion particles having first light conversion properties, and

wherein the second conformal coating comprises second light conversion particles having second light conversion properties that are different from the first light conversion properties.

16. A light emitting structure, comprising:

a semiconductor light emitting diode (LED) comprising;

an active region including an n-type layer and a p-type layer;

a light emitting surface;

a bonding surface that is opposite the light emitting surface; and

an n-type pad and a p-type pad that are configured to be bonded to a bonding surface of a package that provides electrical connection to the n-type layer via the n-type pad and the p-type layer via the p-type pad; and

a conformal phosphor coating on at least the light emitting surface,

wherein the conformal phosphor coating includes a phosphor coating ledge extending from around an edge of the LED;

wherein the conformal phosphor coating comprises a first conformal coating that is applied to the LED and a second conformal coating that is applied to the first conformal coating.

17. The light emitting structure according to claim 16, wherein the n-type pad and the p-type pad are coplanar with the bonding surface.

18. The light emitting structure according to claim 16, wherein the LED is wirebond free.

19. The light emitting structure according to claim 16, LED comprises a plurality of LEDS that each include the conformal phosphor coating.

20. The light emitting structure according to claim 16, wherein the LED is vertically oriented and wherein the p-type layer is below the n-type layer.

21. The light emitting structure according to claim 16, wherein the phosphor coating ledge includes at least one surface that is substantially parallel to the bonding surface of the LED.

22. The light emitting structure according to claim 16, wherein the phosphor coating ledge includes a thickness of less than or equal to about 100 μ

m.

23. The light emitting structure according to claim 16, wherein the LED comprises a side surface and a transitional surface that defines a transition between the light emitting surface and the at least one side surface, and

wherein the conformal phosphor coating is formed on the side surface and the transitional surface.

24. The light emitting structure according to claim 16,

wherein the first and second conformal coatings each comprise light conversion particles that are configured to convert a portion of light received from the LED.

25. The light emitting structure according to claim 16,

wherein the first conformal coating comprises first light conversion particles having first light conversion properties, and

wherein the second conformal coating comprises second light conversion particles having second light conversion properties that are different from the first light conversion properties.

26. A light emitting structure, comprising:

one or more semiconductor light emitting diodes (LEDs); and

a conformal phosphor coating comprising a first portion and a second portion, the first portion corresponding to at least one surface of each of said LEDs and the second portion extending from the first portion to form a conformal phosphor wing around an edge of each of said LEDs;

wherein said conformal phosphor wing is supported by each of said LEDs.