Small LED source with high brightness and high efficiency

• US 10,529,902 B2
• Filed: 09/24/2018
• Issued: 01/07/2020
• Est. Priority Date: 11/04/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Soraa, Inc.
• Inventors: David, Aurelien J. F., Aldaz, Rafael, Krames, Michael Ragan, Steranka, Frank M., Huang, Kevin, Trottier, Troy
• Primary Examiner(s): Kusumakar, Karen
• Assistant Examiner(s): Bowen, Adam S
• Application Number:
  US16/139,609
• Publication Number:
  US 20190035989A1
• Time in Patent Office: 470 Days
• Field of Search: 257 98
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• 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

Abstract

Small LED sources with high brightness and high efficiency apparatus including the small LED sources and methods of using the small LED sources are disclosed.

Claims

1. A light source comprising:

an LED die, wherein said LED die has a footprint with an area less than 300 μ

m², and wherein said LED die comprises at least,

a light-emitting region;

at least one p-contact electrode disposed on one side of said light-emitting region; and

an n-contact electrode having a first surface facing said light-emitting region and a second surface facing away from said light-emitting region, wherein said first surface is less than 20% of said area.

2. The light source of claim 1, wherein said first surface is smaller than said second surface.

3. The light source of claim 2, wherein said first surface is no more than ⅕

of said second surface.

4. The light source of claim 2, wherein said n-contact is disposed on the same side of said light-emitting region as said p-contact.

5. The light source of claim 4, wherein a portion of said n-contact underlays at least a portion of said p-contact.

6. The light source of claim 5, wherein a dielectric is disposed between said portion of said n-contact and said at least a portion of said p-contact.

7. The light source of claim 6, wherein the n-electrode extends beyond said base for contacting.

8. The light source of claim 1, wherein said LED die has a flip-chip configuration.

9. The light source of claim 1, wherein light emission occurs substantially from said light-emitting region over said at least one p-contact electrode.

10. The light source of claim 1, wherein said p-contact is disposed on one side of the light-emitting region, and said n-contact is disposed on the opposite side of said light-emitting region.

11. The light source of claim 10, wherein the second surface is wire bonded.

12. The light source of claim 10, wherein said LED die further comprises a current-blocking region substantially aligned with the n-contact electrode.

13. The light source of claim 1, wherein the LED is in a vertical chip configuration.

14. The light source of claim 13, wherein light emission occurs substantially from said light-emitting region over said at least one p-contact electrode.

15. The light source of claim 1, wherein said LED die further comprises sidewalls that are passivated.

16. The light source of claim 15, wherein said sidewalls are passivated by a dielectric layer.

17. The light source of claim 1, wherein said LED die is configured to operate at a current density higher than 100 A/cm².

18. The light source of claim 1, wherein said LED die further comprises a substrate comprising bulk GaN.

19. A light source comprising:

an LED die, said LED die having

a footprint area less than 300 μ

m² and a light-emitting region configured for emitting white light;

at least one p-contact electrode disposed on one side of said light-emitting region; and

an n-contact electrode having a first surface facing said light-emitting region and a second surface facing away from said light-emitting region, wherein said first surface is less than 20% of said area.

20. The light source of claim 19, wherein said first surface is smaller than said second surface.