Method of forming LED-based light and resulting LED-based light

• US 7,976,196 B2
• Filed: 07/09/2008
• Issued: 07/12/2011
• Est. Priority Date: 07/09/2008
• Status: Active Grant

• Current Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Original Assignee: Altair Engineering Incorporated
• Inventors: Simon, David L, Ivey, John
• Primary Examiner(s): Sember; Thomas M
• Application Number:
  US12/169,918
• Publication Number:
  US 20100008085A1
• Time in Patent Office: 1,098 Days
• Field of Search: 362/218, 362/294, 362/373, 362/249.02, 362/249.06, 362/249.14
• US Class Current: 362/294
• CPC Class Codes: F21K 9/27 Retrofit light sources for lighting devices with two fittings for each light source, e.g. for substitution of fluorescent tubes
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21V 29/507 of means for protecting lighting devices from damage, e.g. housings
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 29/85 characterised by the material liquid coolants F21V29/56
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A method of forming a LED-based light for replacing a conventional fluorescent bulb in a fluorescent light fixture includes shaping an elongate sheet of highly thermally conductive material to fashion a heat sink. Shaping the heat sink allows fashioning the heat sink to define cover and end cap attachment structures, surfaces for mounting LEDs at various angles, and a high surface area to width ratio for dissipating heat.

Claims

1. A method of forming a LED-based light for replacing a conventional fluorescent bulb in a fluorescent light fixture and including a plurality of LEDs, an elongate heat sink, an elongate light transmitting cover, the method comprising:

providing the heat sink by shaping an elongate sheet of highly thermally conductive material to include a plurality of longitudinally extending surfaces;

wherein at least one longitudinal vertex is formed between two adjacent longitudinally extending surfaces;

mounting the plurality of LEDs in thermally conductive relation with and substantially along a length of at least one of the plurality of longitudinally extending surfaces; and

enclosing the plurality of LEDs within the light transmitting cover such that the at least one longitudinal vertex engages an interior of the cover.

2. The method of claim 1, wherein at the least one of the plurality of longitudinally extending surfaces is a planar surface, and further comprising:

mounting the LEDs to a circuit board; and

attaching the circuit board to the planar surface.

3. The method of claim 2, further comprising:

shaping at least one longitudinally extending open fin into the planar surface for dividing the planar surface into two parallel planar surfaces separated by a depression; and

mounting the circuit board on the two parallel planar surfaces such that it spans the depression.

4. The method of claim 1, further comprising:

securing a circuit board to each of at least some of the plurality of longitudinally extending surfaces and

mounting a first group of LEDs on the circuit board secured to a first of the plurality of longitudinally extending surfaces and mounting a second group of LEDs on the circuit board secured to a second of the plurality of longitudinally extending surfaces.

5. The method of claim 4, wherein the first longitudinally extending surface and the second longitudinally extending surface are angled relative to one another by approximately one of 60°

, 90° and

180°

.

6. The method of claim 4, wherein the plurality of longitudinally extending surfaces form least one at least one of a rectangular and a triangular cross-section, further comprising:

mounting LEDs on each of the plurality of longitudinally extending surfaces for emitting light through an entire circumference of the cover.

7. The method of claim 1 wherein the LED-based light includes at least one electrical connector, further comprising:

shaping the heat sink to have a high surface area to width ratio and a substantially constant thickness; and

attaching the at least one electrical connector adjacent to a longitudinal end of the heat sink.

8. An LED-based light for replacing a conventional fluorescent bulb in a fluorescent light fixture formed according to the method of claim 1, wherein:

the light transmitting cover at least partially defines a tubular housing;

the heat sink has a high surface area to width ratio;

the at least one longitudinal vertex engages an interior of the cover; and

the plurality of LEDs are enclosed within the tubular housing and mounted in thermally conductive relation with and substantially along a length of at least one of the plurality of longitudinally extending surfaces for emitting light through the cover.

9. The LED-based light of claim 8, wherein the heat sink has a substantially constant thickness.

10. The LED-based light of claim 8, wherein the at least one of the plurality of longitudinally extending surfaces is a planar surface, and wherein at least one LED of the plurality of LEDs is mounted to an elongate circuit board secured to the planar surface.

11. The LED-based light of claim 8, wherein the heat sink includes multiple longitudinally extending planar surfaces angled relative to one another for securing a plurality of circuit boards in different orientations onto the heat sink;

and

a first group of LEDs mounted on a first of the multiple planar surfaces and a second group of LEDs on a second of the multiple planar surfaces.

12. The LED-based light of claim 8, wherein the LED-based light includes at least one electrical connector at a longitudinal end of the tubular housing in electrical connection with the plurality of LEDs.

13. The LED-based light of claim 8, wherein the heat sink defines at least one open fin.

14. The LED-based light of claim 8, wherein the plurality of longitudinally extending surfaces includes two surfaces spaced apart in a direction perpendicular to the length the heat sink by a distance substantially equal to a width of a fastener for securing an electrical connector to the heat sink by engaging the fastener between the two surfaces.

15. The method of claim 1, wherein the shaping provides fins.

16. The method of claim 15, wherein the fins are open.

17. The method of claim 15, wherein the fins are closed.

18. The method of claim 1 wherein the plurality of longitudinally extending surfaces includes two surfaces spaced apart in a direction perpendicular to a longitudinal axis of the heat sink by a distance substantially equal to a width of a fastener, further comprising:

securing the fastener between the two surfaces for attaching an end cap to the heat sink.

19. An LED-based light for replacing a conventional fluorescent light bulb in a fluorescent light fixture, the LED-based light comprising:

a hollow, cylindrical light transmitting tube;

a heat sink shaped from a sheet of highly thermally conductive material having a width greater than a maximal width of the tube, the heat sink having a central planar portion and two side portions extending perpendicularly to the planar portion from opposing ends of the planar portion, the heat sink positioned within the tube with the side portions in contact with an interior of the tube;

a printed circuit board mounted on the central planar portion;

multiple LEDs longitudinally spaced along the length of the circuit board; and

two end caps coupled to opposing ends of the tube, the end caps carrying bi-pin connectors in electrical communication with the circuit board.

20. The LED-based light of claim 19, wherein the heat sink has a substantially constant thickness.

21. The LED-based light of claim 19, further comprising:

at least one other circuit board mounted on at least one of the two side portions, wherein multiple LEDs are longitudinally spaced along the length of the at least one other circuit board.

22. The LED-based light of claim 19, wherein the at least one other circuit board is mounted on at least one of the two side portions, wherein multiple LEDs are longitudinally spaced along the length of the at least one other circuit board.