METHOD OF FORMING LED-BASED LIGHT AND RESULTING LED-BASED LIGHT

• US 20100008085A1
• Filed: 07/09/2008
• Published: 01/14/2010
• Est. Priority Date: 07/09/2008
• Status: Active Grant

• Current Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Original Assignee: Altair Engineering Incorporated
• Inventors: Ivey, John, Simon, David L.
• Granted Patent: US 7,976,196 B2
• Time in Patent Office: Days
• US Class Current: 362/218
• 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, and at least one electrical connector, the method comprising:

providing the heat sink by shaping an elongate sheet of highly thermally conductive material to increase a surface area to width ratio thereof;

mounting the LEDs in thermally conductive relation with the heat sink along its length; and

enclosing the LEDs within the light transmitting cover.

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

3. The method of claim 2, wherein the fins are open.

4. The method of claim 2, wherein the fins are closed.

5. The method of claim 1, wherein the enclosing step includes engaging longitudinal edges of the cover with the heat sink.

6. The method of claim 1, further comprising:

shaping at least one longitudinally extending planar surface into the heat sink;

mounting the LEDs to a circuit board; and

attaching the circuit board to the planar surface.

7. The method of claim 6, further comprising:

shaping at least one longitudinally extending open fin into the at least one 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.

8. The method of claim 6, further comprising:

shaping multiple longitudinally extending planar surfaces angled relative to one another into the heat sink for securing a plurality of circuit boards in different orientations onto the heat sink; and

mounting a first group of LEDs on a first of the multiple planar surface and mounting a second group of LEDs on a second of the multiple planar surface.

9. The method of claim 8, wherein the first planar surface and second planar surface are angled apart from one another by approximately one of 60°

, 90° and

180°

.

10. The method of claim 8, further comprising:

shaping at least one of the multiple planar surfaces to include at least one additional planar surface such that the heat sink has at least one of a rectangular and a triangular cross-section by; and

mounting LEDs on each of the multiple planar surfaces and the at least one additional planar surface for emitting light through an entire circumference of the cover.

11. The method of claim 1, further comprising:

shaping the heat sink to include 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; and

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

12. The method of claim 1, further comprising:

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

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

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

a light transmitting cover at least partially defining a tubular housing;

a highly thermally conductive heat sink engaged with the cover, the heat sink having a high surface area to width ratio;

multiple LEDs enclosed within the tubular housing and mounted in thermally conductive relation at along a length of the heat sink for emitting light through the cover; and

at least one electrical connector at a longitudinal end of the tubular housing in electrical communication with the multiple LEDs.

14. The LED-based light of claim 13, wherein the heat sink has a substantially constant thickness.

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

16. The LED-based light of claim 13, wherein the longitudinal edges of the cover are engaged with the heatsink.

17. The LED-based light of claim 13, wherein the heat sink includes a longitudinally extending planar surface, and wherein the at least one LED is mounted to an elongate circuit board secured to the planar surface.

18. The LED-based light of claim 13, wherein the heat sink 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 one of the electrical connectors to the heat sink, and wherein the electrical connector is secured to the heat sink by engaging the fastener between the two surfaces.

19. The LED-based light of claim 13, 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.

20. An LED-based light for replacing a conventional fluorescent light bulb a in 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 hi contact with an interior of the tube;

a printed circuit board mounted on the central planar surface;

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.