System for actively cooling an LED filament and associated methods

• US 9,360,202 B2
• Filed: 01/07/2015
• Issued: 06/07/2016
• Est. Priority Date: 05/13/2011
• Status: Active Grant

• Current Assignee: Lighting Science Group Corporation (Pegasus Capital Advisors, L.P.)
• Original Assignee: Lighting Science Group Corporation (Pegasus Capital Advisors, L.P.)
• Inventors: Maxik, Fredric S, Bartine, David E, Soler, Robert R, Zhou, Ran, Widjaja, Addy S, Bastien, Valerie A, Oostdyk, Mark Andrew
• Primary Examiner(s): Dzierzynski, Evan
• Assistant Examiner(s): Dunay, Christopher E
• Application Number:
  US14/591,521
• Publication Number:
  US 20150159853A1
• Time in Patent Office: 517 Days
• US Class Current: 1/1
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21V 23/009 the casing being inside the housing of the lighting device
• CPC Class Codes: F21V 29/503 of light sources cooling arrangements structurally associated with gas-discharge or vapour-discharge lamps H01J61/52; cooling arrangements structurally associated with electric incandescent lamps H01K1/58; cooling arrangements structurally associated with light-emitting diodes H01L33/64
• CPC Class Codes: F21V 29/59 with forced flow of the coolant
• CPC Class Codes: F21V 29/65 the gas flowing in a closed circuit
• CPC Class Codes: F21V 29/78 with helically or spirally arranged fins or blades
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A lighting device may include a base, a housing, a driver circuit, an optic, a thermally-conductive fluid, a LED filament structure, and a fluid flow generator. The base may have an electrical contact. The housing may be attached to the base at a first end and have an internal cavity. The driver circuit may be positioned within the internal cavity and may be in electrical communication with the electrical contact. The optic may be attached to a second end of the housing and have an inner surface which may define an optical chamber. The thermally-conductive fluid may be positioned within the optical chamber. The LED filament structure may be positioned within the optical chamber and may be in electrical communication with the driver circuit. The fluid flow generator may be positioned in fluid communication with the optical chamber and may be in electrical communication with the driver circuit.

Claims

1. A lighting device comprising:

a base having an electrical contact;

a housing attached to the base at a first end and having an internal cavity;

a driver circuit positioned within the internal cavity and in electrical communication with the electrical contact;

an optic having an inner surface defining an optical chamber, the optic being attached to a second end of the housing;

a thermally-conductive fluid positioned within the optical chamber;

a light-emitting diode (LED) filament structure positioned within the optical chamber and in electrical communication with the driver circuit,

the LED filament structure comprising;

an upper bracket defined as a polygonal frame,

a lower bracket defined as a polygonal frame,

a plurality of LED filaments formed as buttresses connecting the upper and lower frames, and

a filament support comprised of a plurality of buttresses extending distally from the housing; and

a fluid flow generator positioned in fluid communication with the optical chamber and electrical communication with the driver circuit;

wherein the fluid flow generator is adapted to generate a flow of the thermally-conductive fluid in the direction of the LED filament structure.

2. The lighting device according to claim 1 wherein the LED filament structure comprises a plurality of LED dies;

and wherein the flow of thermally conductive fluid generated by the fluid flow generator is directed towards at least one LED die of the LED filament structure.

3. The lighting device according to claim 1 wherein the LED filament structure comprises a plurality of LED dies;

wherein the plurality of LED dies are arranged so as to define a light-emitting length of the LED filament structure; and

wherein the flow of thermally-conductive fluid generated by the fluid flow generator is directed to be incident upon the entire light-emitting length of the LED filament structure.

4. The lighting device according to claim 1 wherein the LED filament structure defines a longitudinal axis;

and wherein the flow of thermally-conductive fluid is in a direction of at least one of generally perpendicular to the longitudinal axis of the LED filament structure and generally parallel to the longitudinal axis of the LED filament structure.

5. The lighting device according to claim 1 wherein the fluid flow generator is positioned generally intermediate the driver circuit and the LED filament structure.

6. The lighting device according to claim 1 further comprising a flow redirection structure configured to redirect fluid flow incident thereupon about the optical chamber;

and wherein the flow of thermally-conductive fluid generated by the fluid flow generator is in the direction of the flow redirection structure.

7. The lighting device according to claim 6 wherein the flow redirection structure is configured to redirect fluid flow incident thereupon about at least a portion of the optical chamber.

8. The lighting device according to claim 6 wherein the flow redirection structure is positioned proximate to an apex of the optical chamber;

and wherein the fluid flow generator is positioned proximate to a nadir of the optical chamber.

9. The lighting device according to claim 6 wherein the flow redirection structure is configured to redirect at least a portion of the fluid flow incident thereupon generally in the direction of the fluid flow generator.

10. The lighting device according to claim 1 wherein the optical chamber and the internal cavity are in fluid communication with each other;

and wherein the thermally-conductive fluid is positioned within both the optical chamber and the internal cavity.

11. The lighting device of claim 1 further comprising a heat sink positioned in thermal communication with at least one of the LED filament structure and the driver circuit;

wherein the fluid flow generator is positioned to direct the flow of thermally conductive fluid towards at least one of the heat sink, the driver circuit, and the LED filament structure.

12. The lighting device of claim 1 wherein the fluid flow generator is a microblower device.

13. The lighting device of claim 1 wherein the thermally-conductive fluid is at least one of air, helium, neon, and nitrogen.

14. The lighting device of claim 1 wherein the optical chamber and the Internal cavity combine to define an interior volume;

and wherein the interior volume is fluidically sealed.

15. The lighting device of claim 1 wherein the LED filament structure has a curvature that is approximately equal to a curvature of the inner surface of the optic.

16. The lighting device of claim 15 wherein the LED filament structure is configured to generally conform to the curvature of the optic that conforms to a bulb configuration selected from the group consisting of A19, A15, A21, ST19, ST15, S21, S11, C7, G25, G20, PAR30, PAR20, BR30, BR40, and R20.

17. The lighting device of claim 2 wherein the plurality of LED dies and the LED filament structure are configured to emit light away from the lighting device at least one of semi-hemispherically, hemispherically, and spherically.

18. A lighting device comprising:

a base having an electrical contact;

a housing attached to the base at a first end and having an internal cavity;

a driver circuit positioned within the internal cavity and in electrical communication with the electrical contact;

an optic having an inner surface defining an optical chamber, the optic being attached to a second end of the housing;

a thermally-conductive fluid positioned within the optical chamber;

a light-emitting diode (LED) filament structure positioned within the optical chamber and in electrical communication with the driver circuit, comprising a plurality of LED dies, the LED filament structure comprising;

an upper bracket defined as a polygonal frame,

a lower bracket defined as a polygonal frame,

a plurality of LED filaments formed as buttresses connecting the upper and lower frames, and

a filament support comprised of a plurality of buttresses extending distally from the housing; and

a fluid flow generator positioned in fluid communication with the optical chamber and electrical communication with the driver circuit;

wherein the fluid flow generator is positioned proximate to a nadir of the optical chamber;

wherein the plurality of LED dies are arranged so as to define a light emitting length of the LED filament structure; and

wherein the fluid flow generator is adapted to generate a flow of the thermally-conductive fluid to be incident upon the entire light-emitting length of the LED filament structure.

19. The lighting device according to claim 18 further comprising a flow redirection structure adapted to redirect fluid flow incident thereupon over at least part of the inner surface of the optic;

and wherein the flow of thermally-conductive fluid generated by the fluid flow generator is in the direction of the flow redirection structure.

20. A lighting device comprising:

a base having an electrical contact;

a housing attached to the base at a first end and having an internal cavity;

a driver circuit positioned within the internal cavity and in electrical communication with the electrical contact;

an optic having an inner surface defining an optical chamber, the optic being attached to a second end of the housing;

a thermally-conductive fluid positioned within the optical chamber;

a light-emitting diode (LED) filament structure positioned within the optical chamber and in electrical communication with the driver circuit, the LED filament structure comprising;

an upper bracket defined as a circular frame,

a lower bracket defined as a circular frame,

a plurality of LED filaments formed as buttresses connecting the upper and lower frames, and

a filament support comprised of a plurality of buttresses extending distally from the housing; and

a fluid flow generator positioned in fluid communication with the optical chamber and electrical communication with the driver circuit;

wherein the fluid flow generator is positioned generally intermediate the driver circuit and the LED filament structure; and

wherein the fluid flow generator is adapted to generate a flow of the thermally-conductive fluid in the direction of at least one of the driver circuit and the LED filament structure.

21. The lighting device of claim 20 further comprising a flow redirection structure adapted to redirect fluid flow incident thereupon about at least part of the optical chamber;

and wherein the flow of thermally-conductive fluid generated by the fluid flow generator is in the direction of the flow redirection structure.