Lamp assembly utilizing light emitting diodes

• US 8,277,092 B2
• Filed: 10/12/2007
• Issued: 10/02/2012
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: Truck-Lite Company LLC (Truck-Lite Holdings 2 Corp.)
• Original Assignee: Truck-Lite Company LLC (Truck-Lite Holdings 2 Corp.)
• Inventors: Dunn, Timothy
• Primary Examiner(s): Ward, John A
• Application Number:
  US11/974,255
• Publication Number:
  US 20090097264A1
• Time in Patent Office: 1,817 Days
• Field of Search: 362/265, 362/264, 362/373
• US Class Current: 362/373
• 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 15/01 Housings, e.g. material or assembling of housing parts F21V15/02 takes precedence housings forming signs or letters G09F13/04
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 29/763 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 29/85 characterised by the material liquid coolants F21V29/56
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/35 Balancing circuits
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/397 Current mirror circuits
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines
• CPC Class Codes: H05B 45/56 involving measures to prevent abnormal temperature of the LEDs
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A lamp assembly is provided. The lamp assembly has a housing that functions as a heat sink for the dissipation of heat therefrom. A circuit board assembly is carried by the housing and has a drive circuit that has a current regulator. A plurality of light emitting diodes are also present and are configured to be driven by a current source regulated by the current regulator so as to decrease the amount of heat generated through driving the plurality of light emitting diodes such that the housing is optimally sized to still function effectively as a heat sink.

Claims

1. A lamp assembly, comprising:

a housing having an exterior side surface with a lens abutting edge at one end and a back wall abutting edge at a second end, a back wall with an interior surface and an exterior surface, at least one fin for use in dissipating heat from said housing, wherein the at least one fin extends from the exterior surface of the back wall by a length approximately equal to or less than the length of the exterior side surface from the lens abutting edge to the back wall abutting edge, wherein said housing functions as a heat sink;

circuit board assembly positioned adjacent to the interior surface of the back wall of the housing, wherein said circuit board assembly has a drive circuit including at least one current regulator for use in driving a plurality of light emitting diodes;

said plurality of light emitting diodes coupled to the circuit board assembly, wherein said light emitting diodes are configured to be driven by a current source regulated the at least one current regulator so as to reduce the amount of heat needed to be dissipated from said housing such that the at least one fin of a length approximately equal to or less than the length of the exterior side surface is sufficient for dissipating heat from the lamp assembly.

2. The lamp assembly as set forth in claim 1, wherein said plurality of light emitting diodes are arranged into a plurality of light emitting diode banks that each have a plurality of said of light emitting diodes connected in series;

and

wherein said circuit board assembly has a plurality of linear current regulators, wherein each one of said linear current regulators is associated with a different one of said plurality of light emitting diode banks, wherein each one of said linear current regulators is configured for regulating the current flowing through said plurality of light emitting diodes in said light emitting diode bank to which said linear current regulator is associated.

3. The lamp assembly as set forth in claim 1, wherein said plurality of light emitting diodes are arranged into a plurality of light emitting diode banks that each have a plurality of said light emitting diodes connected in series, wherein each said light emitting diode bank has a ballasting resistor configured for limiting the flow of current through said light emitting diode bank;

and

wherein said circuit board assembly has a switch mode current regulator for regulating the flow of current through said plurality of light emitting diode banks, wherein said switch mode current regulator has an inductor, and wherein said switch mode current regulator is configured for regulating current by varying the duty cycle of power applied to said inductor.

4. The lamp assembly as set forth in claim 1, wherein said plurality of light emitting diodes are arranged into a plurality of light emitting diode banks that each have a plurality of said light emitting diodes connected in series, wherein said plurality of light emitting diode banks are connected in parallel to one another;

wherein said circuit board assembly has a switch mode current regulator for regulating the flow of current through said plurality of light emitting diode banks, wherein said switch mode current regulator has an inductor, and wherein said switch mode current regulator is configured for regulating current by varying the duty cycle of power applied to said inductor; and

wherein said circuit board assembly has a current mirror configured to effect the regulated current in said plurality of light emitting diode banks such that the same amount of current flows through each one of said plurality of light emitting diode banks.

5. The lamp assembly as set forth in claim 1, wherein said plurality of light emitting diodes are arranged into a plurality of light emitting diode banks that each have a plurality of said light emitting diodes connected in series, wherein said plurality of light emitting diode banks are connected in parallel to one another;

wherein said circuit board assembly has a linear current regulator associated with a first one of said plurality of light emitting diode banks, wherein said linear current regulator is configured for regulating the current flowing through said plurality of light emitting diodes in said first light emitting diode bank; and

wherein said circuit board assembly has a current mirror configured to affect the current in additional light emitting diode banks of said plurality of fight emitting diode banks such that the same amount of current flows through each one of said additional light emitting diode banks of said plurality of light emitting diode banks as flows through said first fight emitting diode bank.

6. The lamp assembly as set forth in claim 1, wherein said circuit board assembly is made of a flame resistant material.

7. The lamp assembly as set forth in claim 1, wherein a thermal interface is not present between said circuit board assembly and said interior surface of said housing.

8. The lamp assembly as set forth in claim 1, wherein said exterior side surface is curved and includes a plurality of fins extending perpendicularly therefrom for use in dissipating heat from said housing.

9. The lamp assembly as set forth in claim 8, wherein said plurality of fins on said exterior side surface are parallel to one another.

10. The lamp assembly as set forth in claim 1, wherein a plurality of fins for use in dissipating heat from said housing are located on said exterior side surface.

11. The lamp assembly as set forth in claim 10, wherein said plurality of fins on said exterior side surface are parallel to one another along at least half of the length of said exterior side surface.

12. The lamp assembly as set forth in claim 1, wherein a thermal interface material is positioned between said circuit board assembly and said interior surface of the housing, wherein the thermal interface material is a phase change material.

13. A lamp assembly, comprising:

a housing having an exterior side surface having a lens abutting edge at one end and a back wall abutting edge at a second end, a back wall with an interior surface and an exterior surface, wherein the exterior side surface includes a first plurality of fins extending perpendicularly therefrom, and wherein a second plurality of fins extending from said exterior surface of the back wall, wherein said first plurality and second plurality of fins are for use in dissipating heat from said housing thereby functioning as a heat sink;

a circuit board assembly positioned adjacent to the interior surface of said housing, wherein said circuit board assembly has a drive circuit that has a current regulator; and

a plurality of light emitting diodes, wherein said light emitting diodes are configured to be driven by a current source regulated by said current regulator so as to reduce the amount of heat needed to be dissipated from said housing, wherein said plurality of light emitting diodes are arranged into a plurality of light emitting diode banks that each have a plurality of said of light emitting diodes connected in series,

wherein said circuit board assembly has a plurality of linear current regulators, wherein each one of said linear current regulators is associated with a different one of said plurality of light emitting diode banks, wherein said linear current regulators function as drive circuitry and are configured for regulating the current flowing through said plurality of light emitting diodes in said light emitting diode bank to which said linear current regulator is associated so as to reduce the amount of heat needed to be dissipated from said housing.

14. The lamp assembly of claim 13 wherein the second plurality of fins extends from the exterior surface of the back wall a length approximately equal to or less than the length of the exterior side surface.