Light System and Method to Thermally Manage an LED Lighting System

• US 20090129087A1
• Filed: 11/17/2008
• Published: 05/21/2009
• Est. Priority Date: 11/15/2007
• Status: Abandoned Application

• Current Assignee: Engineering Innovation and Design, Inc.
• Original Assignee: Engineering Innovation and Design, Inc.
• Inventors: Starkey, Carl R., Matthews, James D., Carr, William L.
• Application Number:
  US12/272,019
• Publication Number:
  US 20090129087A1
• Time in Patent Office: Days
• US Class Current: 362/249.20
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05K 1/0206 by printed thermal vias
• CPC Class Codes: H05K 1/0272 Adaptations for fluid transport, e.g. channels, holes
• CPC Class Codes: H05K 2201/09781 Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 3/42 Plated through-holes or plated via connections

Abstract

A method of cooling light emitting diode (LED) lighting systems and associated structures are disclosed and claimed herein. The method involves determining the areas of a printed circuit board (PCB) onto which LEDs will be mounted will have the highest temperature during operation and positioning thermal vias of a certain size in or adjacent that area. The thermal vias extend from the PCB first side through the PCB substrate to the PCB second side to allow fluid flow through the PCB. The thermal vias are coated with a plating so that thermal energy is conductively transferred from the area adjacent an LED or resistor to the thermal via. From the thermal via the thermal energy may be dissipated to the atmosphere adjacent the thermal via through various modes. Novel structures according to the present invention include LED circuits, light fixtures, PCBs, and various combinations thereof employing the thermal vias.

Claims

1. A light emitting diode (LED) light fixture comprising:

a. a printed circuit board (PCB) having a first and second side;

b. at least one LED pad, said at least one LED pad mounted on either said PCB first or second side;

c. a plurality of LEDs mounted on said first side of said PCB in electrical communication with said at least one LED pad; and

d. at least one thermal via positioned adjacent at least one LED of said plurality, wherein said at least one thermal via allows a flow of air between said PCB first and second sides, wherein said at least one thermal via is coated with a plating, and wherein said plating is in conductive thermal communication with said at least one LED pad.

2. A light emitting diode (LED) light fixture comprising:

a. a housing;

b. a power supply mounted adjacent said housing, wherein said power supply is capable of connection to an electrical energy source;

c. a printed circuit board (PCB) mounted within said housing having a first and a second side, wherein said PCB is configured to be connected to said power supply, wherein said PCB comprises;

i. a PCB substrate;

ii. at least one power conductive pathway affixed to said PCB substrate;

iii. at least one ground conductive pathway affixed to said PCB substrate;

iv. at least one LED pad affixed to said PCB substrate;

v. at least one resistor pad affixed to said PCB substrate;

vi. a plurality of electrical lead apertures extending from said PCB first side through said PCB substrate to said PCB second side, wherein said electrical lead apertures a coated with a plating; and

vii. a plurality of thermal vias extending from said PCB first side through said PCB substrate to said PCB second side, wherein said thermal vias are coated with a plating;

d. at least one resistor electrically connected to said at least one power conductive pathway and said at least one resistor pad through two electrical lead apertures of said plurality;

e. at least one LED electrically connected to said at least one LED pad and said at least one resistor pad through two electrical lead apertures of said plurality; and

f. at least one LED electrically connected to at least two adjacent LED pads through two electrical lead apertures of said plurality, wherein said plurality of thermal vias and said at least one LED are configured to dissipate heat through the PCB first side, PCB second side, and said plurality of thermal vias.

3. The LED light fixture according to claim 2 wherein said PCB is further defined as having three LED board sections, wherein each said LED board section is electrically connected to said power supply through a power conductive pathway and a ground conductive pathway.

4. The LED light fixture according to claim 3 wherein each said LED board section is further defined as including a plurality of LED circuits.

5. The LED light fixture according to claim 4 wherein each LED circuit comprises:

a. a first resistor pad on said PCB first side;

b. a second resistor pad on said PCB second side;

c. a first LED pad adjacent said first resistor pad;

d. a second LED pad adjacent said second resistor pad;

e. a resistor electrically connecting said first and second resistor pads to said power conductive pathway;

f. a first LED, wherein said first LED electrically connects said first and second resistor pads to said first and second LED pads; and

g. a plurality of intermediate LED pads, wherein each intermediate LED pad is electrically connected to either an adjacent intermediate LED pad or said ground conductive pathway by at least one intermediate LED.

6. The LED light fixture according to claim 5 wherein said LED circuit is further defined as comprising a total of seven LEDs.

7. The LED light fixture according to claim 6 wherein said plurality of thermal vias is further defined as including three thermal vias for each LED.

8. The LED light fixture according to claim 7 wherein said three thermal vias are positioned on the portion of LED pad having highest amount of thermal energy in the absence of said thermal vias.

9. The LED light fixture according to claim 2 wherein the arrangement of LEDs is non-linear.

10. The LED light fixture according to claim 2 wherein the diameter of said plurality of thermal vias varies from one thermal via to the next.

11. The LED light fixture according to claim 2 wherein said PCB substrate is further defined as being constructed of an epoxy glass.

12. The LED light system according to claim 2, wherein said PCB is further defined as being constructed from a group including glass fiber mat, nonwoven material, resin, FR-2 (Phenolic cotton paper), FR-3 (Cotton paper and epoxy), FR-4 (Woven glass and epoxy), FR-5 (Woven glass and epoxy), FR-6 (Matte glass and polyester), G-10 (Woven glass and epoxy), CEM-1 (Cotton paper and epoxy), CEM-2 (Cotton paper and epoxy), CEM-3 (Woven glass and epoxy), CEM-4 (Woven glass and epoxy), CEM-5 (Woven glass and polyester), polyimide, Teflon, ceramics, and combinations thereof.

14. The LED circuit according to claim 12 wherein said LED circuit is further defined as including one resistor pad and twelve LED pads.

13. A light emitting diode (LED) circuit comprising:

a. a printed circuit board (PCB), wherein said PCB has a first and a second side, said PCB comprising;

i. a PCB substrate;

ii. at least one power conductive pathway positioned on either said PCB first or second side configured for electrical connection to a power supply;

iii. at least one ground conductive pathway positioned on either said PCB first or second side configured for electrical connection to a power supply;

iv. at least one resistor pad positioned on either said PCB first or second side;

v. at least one LED pad positioned on either said PCB first or second side;

vi. a plurality of electrical lead apertures, wherein said lead apertures extend from said PCB first side through said PCB substrate to said PCB second side; and

vii. a plurality of thermal vias, wherein each said thermal via extends from said PCB first side through said PCB substrate to said PCB second side, wherein each said thermal via is positioned either in said at least one LED pad or said at least one resistor pad, wherein each said thermal via is coated with a plating, and wherein each said thermal via is in thermal communication with either said at least one LED pad or said at least one resistor pad;

b. at least one resistor, wherein said resistor electrically connects two lead apertures of said plurality of lead apertures;

c. at least one LED, wherein said at least one LED electrically connects two electrical lead apertures of said plurality of electrical lead apertures, wherein said at least one power conductive pathway, at least one ground conductive pathway, at least one resistor pad, at least one LED pad, plurality of electrical lead apertures, at least one resistor, and at least one LED are configured so that a plurality of LEDs may be electrically connected in series.

15. The LED circuit according to claim 13 wherein said LED circuit is further defined as including seven LEDs electrically connected in series.

17. The PCB according to claim 15 further comprising:

a. a plurality of intermediate LED pads positioned between said first LED pad and said ground conductive pathway on said PCB first side;

b. a plurality of intermediate LED pads positioned on said PCB second side mirroring the position of said plurality of intermediate LEDpas on said PCB first side;

c. a plurality of intermediate LEDs electrically connecting said plurality of intermediate LED pads in series.

16. A printed circuit board (PCB) for a light emitting diode (LED) light fixture, wherein said PCB has a first and second side, said printed circuit board comprising:

a. a PCB substrate;

b. at least one power conductive pathway positioned on at least said PCB first side, wherein said power conductive pathway is configured to be connected to an electrical energy source at a power connection;

c. at least one ground conductive pathway positioned on at least said PCB first side, wherein said power conductive pathway is configured to be connected to an electrical energy source at a ground connection;

d. a first and a second resistor pad, wherein said first resistor pad is positioned on said PCB first side, and wherein said second resistor pad is positioned on said PCB second side;

e. a first and a second LED pad, wherein said first LED pad is positioned on said printed circuit board first side adjacent said first resistor pad, and wherein said second LED pad is positioned on said PCB first side adjacent said second resistor pad;

f. a first, a second, a third, a fourth, a fifth, and a sixth electrical lead aperture, wherein said lead apertures extend from said PCB first side through said PCB substrate to said PCB second side, wherein said first electrical lead aperture is positioned in said power conductive pathway, wherein said second and third electrical lead apertures are positioned in said first and second resistor pads, wherein said fourth and fifth electrical lead apertures are positioned in said first and second LED pads, and wherein said sixth electrical lead aperture is positioned in said ground conductive pathway;

g. at least one resistor, wherein said resistor electrically connects said first electrical lead aperture to said second electrical lead aperture;

h. a first and a second LED, wherein said first and second LEDs have a first and a second LED lead, respectively, wherein said first LED lead of said first LED is positioned within said third electrical lead aperture, wherein said second LED lead of said first LED is positioned within said fourth electrical lead aperture, wherein said first LED lead of said second LED is positioned within said fifth electrical lead aperture, and wherein said second LED lead of said second LED is positioned within said sixth electrical lead aperture; and

i. a plurality of thermal vias, wherein each said thermal via extends from said PCB first side through said PCB substrate to said PCB second side, wherein each said thermal via is positioned either in said first and second LED pads or said first and second resistor pads, and wherein each said thermal via is in thermal communication with either said first and second LED pads or said first and second resistor pads.

18. A method of dissipating heat generated by a light emitting diode (LED) light fixture comprising:

a. placing a plurality of LED pads on a printed circuit board (PCB), wherein said PCB is configured to be connected to a power supply;

b. placing at least one resistor pad on said PCB;

c. attaching at least one resistor to said at least one resistor pad and said power supply;

d. attaching at least one LED to said at least one LED pad of said plurality and to said at least one resistor pad;

e. attaching at least one LED to two adjacent LED pads of said plurality; and

f. positioning at least one thermal via in at least one LED pad of said plurality adjacent said at least one LED such that said at least one thermal via is in thermal communication with said at least one LED pad of said plurality.

19. The method of dissipating heat generated by an LED light fixture according to claim 18 wherein said method further comprises analytically determining what area on said LED pad will possess the most thermal energy during use, and subsequently positioning said at least one thermal via adjacent that area.

20. The method of dissipating heat generated by an LED light fixture according to claim 18 wherein said method further comprises optimizing the number and diameter of said at least one thermal via for cost and heat dissipation efficiency.

21. The method of dissipating heat generated by an LED light fixture according to claim 18 further comprising determining the quantity and magnitude of ambient air flow required to dissipate sufficient heat so that said at least one LED performs optimally.