Failure mitigation in arrays of light-emitting devices

• US 9,107,272 B2
• Filed: 09/12/2014
• Issued: 08/11/2015
• Est. Priority Date: 01/04/2010
• Status: Active Grant

• Current Assignee: Cooledge Lighting Inc.
• Original Assignee: Cooledge Lighting Inc.
• Inventors: Tischler, Michael A., Schick, Philippe M., Jungwirth, Paul, Sheen, Calvin Wade
• Primary Examiner(s): PHILOGENE, HAISSA
• Application Number:
  US14/484,880
• Publication Number:
  US 20150042231A1
• Time in Patent Office: 333 Days
• Field of Search: 315/90, 315/122, 315/169.1, 315/169.3, 315/185.R, 315/185.S, 315/312, 257/81, 257/82, 257/88, 257/99, 362/249.02, 362/249.06, 362/249.11
• US Class Current: 1/1
• CPC Class Codes: F21K 9/20 Light sources comprising attachment means
• CPC Class Codes: H05B 45/40 Details of LED load circuits
• CPC Class Codes: H05B 45/54 in a series array of LEDs
• CPC Class Codes: H05K 2201/09263 Meander
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2201/10174 Diode
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

In accordance with certain embodiments, an illumination system comprising a plurality of power strings features elements facilitating compensation for failure of one or more light-emitting elements connected along each power string.

Claims

1. An illumination system comprising:

a first power string connectable to a power source, the first power string comprising (i) a first power conductor, (ii) a first plurality of light-emitting elements connected along the first power conductor, and (iii) a second plurality of light-emitting elements connected along the first power conductor, the second plurality of light-emitting elements being distinct from the first plurality of light-emitting elements;

a second power string connectable to the power source in parallel to the first power string, the second power string comprising (i) a second power conductor, (ii) a third plurality of light-emitting elements connected along the second power conductor, and (iii) a fourth plurality of light-emitting elements connected along the first power conductor, the fourth plurality of light-emitting elements being distinct from the third plurality of light-emitting elements; and

a shorting member cross-connecting a portion of the first power string between the first and second pluralities of light-emitting elements with a portion of the second power string between the third and fourth pluralities of light-emitting elements, whereby during operation, upon failure of one of the first plurality of light-emitting elements, all of the first plurality of light-emitting elements cease illumination but the second plurality of light-emitting elements remain illuminated.

2. The system of claim 1, wherein at least one light-emitting element comprises a light-emitting diode.

3. The system of claim 1, wherein at least one light-emitting element comprises an unpackaged light-emitting diode.

4. The system of claim 1, wherein (i) in the first power string, the first and second pluralities of light-emitting elements are electrically connected in series along the first power conductor, and (ii) in the second power string, the third and fourth pluralities of light-emitting elements are electrically connected in series along the second power conductor.

5. The system of claim 1, wherein at least one light-emitting element comprises a phosphorescent material for converting at least a portion of light emitted by the light-emitting element from one set of wavelengths to another.

6. The system of claim 1, wherein at least one light-emitting element is at least one of mechanically or electrically connected to the contacts of a contact pair by an adhesive.

7. The system of claim 6, wherein the adhesive comprises a conductive adhesive.

8. The system of claim 7, wherein the adhesive comprises an anisotropically conductive adhesive.

9. The system of claim 1, wherein at least one light-emitting element is at least one of mechanically or electrically connected to the contacts of a contact pair by solder.

10. The system of claim 1, further comprising a flexible substrate on which the first power string and second power string are disposed.

11. The system of claim 1, wherein at least one of the first and second power strings comprises an element for limiting the current flowing therein.

12. The system of claim 1, wherein at least one of the first or second power strings comprises an element for dividing current between the first and second power strings.

13. The system of claim 1, further comprising a power source for supplying power to the first and second power strings.

14. The system of claim 1, further comprising, disposed over the first and second power strings, at least one of a homogenizing optic or a diffuser.

15. The system of claim 1, wherein, during operation, upon failure of one of the third plurality of light-emitting elements, all of the third plurality of light-emitting elements cease illumination but the fourth plurality of light-emitting elements remain illuminated.

16. The system of claim 15, wherein the second power string comprises one or more additional light-emitting elements electrically connected to the third plurality of light-emitting elements, the third and fourth pluralities of light-emitting elements not including the one or more additional light-emitting elements.

17. The system of claim 16, wherein the one or more additional light-emitting elements are electrically connected to the third plurality of light-emitting elements in series.

18. The system of claim 1, wherein the first power string comprises one or more additional light-emitting elements electrically connected to the first plurality of light-emitting elements, the first and second pluralities of light-emitting elements not including the one or more additional light-emitting elements.

19. The system of claim 18, wherein the one or more additional light-emitting elements are electrically connected to the first plurality of light-emitting elements in series.

20. The system of claim 1, wherein the light-emitting elements of the first and second power strings occupy points on a pattern and the first and second power strings follow nonlinear paths through the pattern, such that the light-emitting elements along each of the first and second power strings are not linearly disposed within the pattern.

21. The system of claim 20, wherein the pattern is a rectilinear grid.