Light emitting diode (LED) arrays including direct die attach and related assemblies

Patent metadata

Field	Value
Publication number	US-9831220-B2
Application number	US-201213424699-A
Country	US
Kind code	B2
Filing date	Mar 20, 2012
Priority date	Jan 31, 2011
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

An electronic device may include a packaging substrate having a packaging face, and the packaging substrate may include positive and negative electrically conductive pads on the packaging face. A plurality of light emitting diodes may be electrically and mechanically coupled to the packaging face of the packaging substrate, with the plurality of light emitting diodes being electrically coupled between the positive and negative electrically conductive pads on the packaging face. A continuous optical coating may be provided on the plurality of light emitting diodes and on the packaging face of the packaging substrate so that the plurality of light emitting diodes are between the optical coating and the packaging substrate.

First claim

That which is claimed is:

1. An electronic device comprising:
a packaging substrate having a packaging face, the packaging substrate including positive and negative electrically conductive pads on the packaging face, wherein the packaging substrate comprises a thermally conductive and electrically insulating material, and wherein the packaging substrate has a backside face opposite the packaging face, the packaging substrate further comprising,
a first backside contact electrically coupled to the positive electrically conductive pad through a first electrically conductive via,
a second backside contact electrically coupled to the negative electrically conductive pad through a second electrically conductive via, and
a metal heat conducting structure on the backside face of the packaging substrate wherein the metal heat conducting structure is electrically isolated from the first and second backside contacts, and wherein the metal heat conducting structure is between the first and second backside contacts on the backside face;

a plurality of light emitting diodes electrically and mechanically coupled to the packaging face of the packaging substrate, wherein the plurality of light emitting diodes are electrically coupled between the positive and negative electrically conductive pads on the packaging face;
a continuous optical coating on the plurality of light emitting diodes and on the packaging face of the packaging substrate so that the plurality of light emitting diodes are between the optical coating and the packaging substrate, wherein the continuous optical coating comprises a layer of a transparent and/or translucent material including a phosphor material therein, wherein an optic area is defined by an area of the packaging face covered by the continuous optical coating; and
wherein each of the plurality of light emitting diodes comprises,
a diode region having first and second opposing faces including therein an n-type layer and a p-type layer,
an anode contact that ohmically contacts the p-type layer and extends on the first face,
a cathode contact that ohmically contacts the n-type layer and extends on the first face, and
a support substrate on the second face of the diode region, wherein the diode region is between the support substrate and the anode and cathode contacts, wherein the anode and cathode contacts are between the n-type layer and the packaging substrate in a direction that is orthogonal with respect to the packaging face of the packaging substrate, wherein the anode and cathode contacts are between the p-type layer and the packaging substrate in the direction that is orthogonal with respect to the packaging face of the packaging substrate, and wherein the support substrate has a thickness of at least about 50 micrometers.

2. The electronic device of claim 1 wherein the plurality of light emitting diodes are configured to generate at least 25 lumens per square millimeter of the optic area while delivering at least 100 lumens per watt of power consumed.

3. The electronic device of claim 1 wherein the plurality of light emitting diodes comprises at least 16 light emitting diodes between the continuous optical coating and the packaging substrate.

4. The electronic device of claim 3 wherein the plurality of light emitting diodes comprises at least 72 light emitting diodes.

5. The electronic device of claim 1 wherein at least one of the light emitting diodes is free of wirebonds.

6. The electronic device of claim 1 wherein for each of the light emitting diodes the anode contact is electrically and mechanically coupled to the packaging substrate using a first metallic bond physically located between the anode contact and the packaging substrate and the cathode contact is electrically and mechanically coupled to the packaging substrate using a second metallic bond physically located between the cathode contact and the packaging substrate.

7. The electronic device of claim 6 wherein a first planar interface is defined between the first backside contact and a first area of the backside face, and wherein a second planar interface is defined between the second backside contact and a second area of the backside face.

8. The electronic device of claim 7 wherein the metal heat conducting structure is aligned with the plurality of light emitting diodes in a direction perpendicular with respect to the packaging face of the packaging substrate, and wherein a third planar interface is defined between the metal heat conducting structure and a third area of the backside face of the packaging substrate.

9. The electronic device of claim 1 wherein for each of the plurality of light emitting diodes, the diode region is between the support substrate and the packaging substrate, the continuous optical coating is coated on the support substrate, and the packaging substrate is free of wirebonds electrically coupled between the packaging substrate and the light emitting diode.

10. The electronic device of claim 1 wherein a thickness of the continuous optical coating relative to the packaging face of the packaging substrate is greater than a thickness of each of the plurality of light emitting diodes relative to the packaging face of the packaging substrate, and wherein a surface of the continuous optical coating opposite the packaging substrate is substantially planar over an area including the plurality of light emitting diodes.

11. The electronic device of claim 1 wherein the optic area is in the range of about 20 square millimeters to about 200 square millimeters.

12. The electronic device of claim 1 wherein the plurality of light emitting diodes comprises a first string of light emitting diodes electrically coupled in series between the positive and negative electrically conductive pads, and a second string of light emitting diodes electrically coupled in series between the positive and negative electrically conductive pads, wherein a node between two light emitting diodes of the first string is electrically coupled to a node between two light emitting diodes of the second string, and wherein at least one of the plurality of light emitting diodes is electrically coupled to the packaging substrate using no more than one wirebond.

13. The electronic device of claim 1 wherein the layer of the transparent and/or translucent material includes multiple different phosphor materials therein, wherein each of the different phosphor materials is configured to emit a respective different wavelength of light responsive to light generated by the plurality of light emitting diodes.

14. The electronic device of claim 1 wherein the plurality of light emitting diodes are configured to generate at least 20 lumens per square millimeter of the optic area while delivering at least 100 lumens per watt of power consumed by the plurality of light emitting diodes between the continuous optical coating and the packaging substrate and while delivering at least 600 absolute lumens from the plurality of light emitting diodes between the continuous optical coating and the packaging substrate.

15. The electronic device of claim 1 wherein the plurality of light emitting diodes comprises first and second light emitting diodes between the continuous optical coating and the packaging substrate wherein the first and second light emitting diodes are spaced apart by a distance in the range of about 20 micrometers to about 500 micrometers.

16. The electronic device of claim 1 wherein a first planar interface is defined between the first backside contact and a first area of the backside face, and wherein a second planar interface i

Assignees

• Donofrio Matthew
• Hussell Christopher P
• Edmond John Adam
• Cree Inc

Inventors

• Donofrio Matthew
• Hussell Christopher P
• Edmond John Adam

Classifications

• H10W90/00 Primary

  Package configurations · CPC title

• H01L33/20

  Electricity · mapped topic

• H01L33/505

  Electricity · mapped topic

• H01L33/62

  Electricity · mapped topic

• H01L25/0753 Primary

  Electricity · mapped topic