Thermal management system for solid state automotive lighting

• US 7,575,354 B2
• Filed: 09/16/2005
• Issued: 08/18/2009
• Est. Priority Date: 09/16/2004
• Status: Active Grant

• Current Assignee: Magna International Incorporated
• Original Assignee: Magna International Incorporated
• Inventors: Woodward, Ronald Owen
• Primary Examiner(s): Choi; Jacob Y
• Application Number:
  US11/575,086
• Publication Number:
  US 20080094850A1
• Time in Patent Office: 1,432 Days
• Field of Search: 362/459, 362/507, 362/543, 362/544, 362/545, 362/547, 362/294, 362/800, 362/296, 362/284
• US Class Current: 362/547
• CPC Class Codes: F21S 41/148 the main emission direction of the LED being perpendicular to the optical axis
• CPC Class Codes: F21S 41/151 arranged in one or more lines
• CPC Class Codes: F21S 45/42 Forced cooling
• CPC Class Codes: F21S 45/48 with means for conducting heat from the inside to the outside of the lighting devices, e.g. with fins on the outer surface of the lighting device
• CPC Class Codes: F21V 23/006 the substrate being distinct from the light source holder
• CPC Class Codes: F21V 29/51 using condensation or evaporation of a fluid, e.g. heat pipes
• CPC Class Codes: F21V 29/54 using thermoelectric means, e.g. Peltier elements
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/717 using split or remote units thermally interconnected, e.g. by thermally conductive bars or heat pipes
• CPC Class Codes: F21V 29/76 with essentially identical parallel planar fins or blades, e.g. with comb-like cross-section
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

An automotive lighting system employing semiconductor light sources includes LED light sources (52) which are mounted to an edge of a heat pipe (44) such that emitted light from the LED light sources travels toward a reflector (32) at the back of the housing (24) of the system, where it is reflected and/or focused forward through the lens (40) of the system. The heat pipe is thermally connected to a heat sink (35) which extends outside of the housing and which operates to remove heat from the LED light sources. The thickness of the heat pipe is significantly less than the size of the reflector, so that only a small amount of reflected light from the LED light sources is obscured.

Claims

1. An automotive lighting system comprising:

a housing having a rearward wall and an opposite forward face;

a lens enclosing said forward face of said housing;

a heat sink including at least one surface outside said housing to radiate heat;

a light source assembly mounted to said housing between said rearward wall and said forward face, said light source assembly including a heat pipe thermally connected to said heat sink and having opposing first and second sides extending between a forward edge facing said forward face and a rearward edge facing said rearward wall of said housing;

at least one semiconductor light source mounted to said rearward edge of said heat pipe and facing said rearward wall of said housing;

an electronic circuit electrically connected to said at least one semiconductor light source for operating said at least one semiconductor light source to emit light; and

a reflector mounted within said housing between the rearward wall and the light source assembly, said reflector being located opposite said lens and facing said rearward edge of said heat pipe such that light emitted by said at least one semiconductor light source is reflected off of said reflector, around said light source assembly and through said lens.

2. The automotive lighting system as claimed in claim 1 wherein the height of said forward and rearward edge is substantially less than the size of said reflector.

3. The automotive lighting system as claimed in claim 1 wherein the at least one semiconductor light source is an LED.

4. The automotive lighting system as claimed in claim 1 wherein the heat pipe serves as one conductor in a circuit to power said at least one semiconductor light source.

5. The automotive lighting system as claimed in claim 4 wherein the electrical connection between said at least one semiconductor light source and said heat pipe further serves as a thermal connection therebetween.

6. The automotive lighting system as claimed in claim 1 including at least two light source assemblies.

7. The automotive lighting system as claimed in claim 1 wherein said electronic circuit is mounted on said heat pipe of said light source assembly.

8. The automotive lighting system as claimed in claim 1 including at least two semiconductor light sources.

9. The automotive lighting system as claimed in claim 1 further comprising a thermal engine between said heat sink and said light source assembly.

10. The automotive lighting system as claimed in claim 9 wherein said thermal engine is a Peltier device.

11. The automotive lighting system as claimed in claim 1 further comprising a thermal engine between said at least one semiconductor light source and said light source assembly.

12. The automotive lighting system as claimed in claim 11 wherein said thermal engine is a Peltier device.

13. The automotive lighting system as claimed in claim 1 further comprising a thermal spreader between said at least one semiconductor light source and said light source assembly, said thermal spreader acting to transfer heat from said at least one semiconductor light source to an area of said light source assembly larger than the area of said at least one semiconductor light source.

14. The automotive lighting system as claimed in claim 13 wherein said thermal spreader further acts as at least one of the electrical conductors between said at least one semiconductor light source and said electronic circuit.