Light fixture for an LED-based aircraft lighting system

• US 7,198,387 B1
• Filed: 12/17/2004
• Issued: 04/03/2007
• Est. Priority Date: 12/18/2003
• Status: Expired due to Fees

• Current Assignee: B/E Aerospace, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: B/E Aerospace, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Gloisten, Jennifer L., Pawelko, Tolek
• Primary Examiner(s): Ward; John Anthony
• Assistant Examiner(s): MAKIYA, DAVID J
• Application Number:
  US11/016,449
• Time in Patent Office: 837 Days
• Field of Search: 362/249, 362/219, 362/294, 362/800, 362/218, 362/227, 362/231, 362/240, 362235-238, 362/457, 362/545, 362/555
• US Class Current: 362/294
• CPC Class Codes: B60Q 3/43 General lighting
• CPC Class Codes: B60Q 3/47 Circuits; Control arrangements
• CPC Class Codes: F21S 4/20 with light sources held by or within elongate supports
• 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 23/006 the substrate being distinct from the light source holder
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 29/767 the planes containing the fins or blades having directions perpendicular to the light emitting axis
• 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]
• CPC Class Codes: H05K 1/0204 using means for thermal conduction connection in the thickness direction of the substrate H05K1/0207 takes precedence

Abstract

A light fixture for housing LED units is provided. The light fixture has a housing that has a substantially H-shaped cross section. The housing has a crossbar with a series of mesas defined on its upper surface. A group of LED units is attached to each of the series of mesas, each LED unit being attached with a thin layer of adhesive. The LED units are electrically insulated from the housing by either the adhesive, which may be electrically insulating, or by an electrically insulating coating on the housing.

Claims

1. A light fixture comprising:

a housing made of thermally conductive material, wherein the housing includes a first side, a second side, and a crossbar connecting the first side to the second side, wherein the second side is displaced from the first side,

wherein the crossbar has an upper surface and a lower surface, and the printed circuit board is attached to the upper surface of the crossbar,

a printed circuit board supported by the housing; and

a light emitting diode unit that is mounted on the housing with a layer of adhesive, the light emitting diode having leads that are electrically connected to the printed circuit board, wherein an electrically insulating material is disposed between the light emitting diode unit and the housing,

wherein at least one mesa extends along the upper surface of the crossbar,

the printed circuit board includes an opening that accommodates a metal back surface of the light emitting diode unit, and

a thermal path extends from back surface of the light emitting diode unit to the at least one mesa.

2. The light fixture of claim 1, wherein the light emitting diode unit is part of a group of light emitting diode units, wherein the group of light emitting diode units includes light emitted diode units that each emit light whose color is different than the light of the other light emitting diode units of the group.

3. The light fixture of claim 1, wherein the layer of adhesive has a low thermal conductivity.

4. The light fixture of claim 1, wherein the layer of adhesive material is electrically insulating.

5. The light fixture of claim 1, wherein the housing is made of aluminum.

6. The light fixture of claim 1, wherein the electrically insulating material is the layer of adhesive.

7. The light fixture of claim 1, wherein the layer of adhesive is electrically conductive.

8. The light fixture of claim 1, wherein the metal back surface of the light emitting diode unit is attached to the mesa through the opening.

9. The light fixture of claim 1, wherein the housing comprises a thermally conductive material that is coated with a finish that inhibits the flow of electric current.

10. The light fixture of claim 1, wherein the layer of adhesive has a low thermal conductivity, the layer being sufficiently thin to permit head to dissipate into the housing from the light-emitting diode unit.

11. A light fixture comprising:

a housing comprising;

a first side and a second side, the first side comprising an inner surface having a substantially straight portion, the second side comprising an inner surface having a substantially straight portion,

wherein the inner surface of the first side of the housing has an angled portion, and the inner surface of the second side of the housing has an angled portion, wherein the angled portions of the inner surfaces of each of the first and second sides are covered in a reflective material, the effect of which is to approximate a parabolic reflector;

a crossbar attached to the substantially straight portion of the first side and to the substantially straight portion of the second side, the cross bar comprising an upper surface and a lower surface, wherein a mesa is defined on the upper surface, the mesa being substantially parallel to the straight portions of the first and second sides of the housing;

a light emitting diode unit having a lens, a base portion, a first lead, and a second lead, wherein the base portion is attached to the mesa with a non-conductive adhesive,

a circuit board disposed on the upper surface of the crossbar; and

a first conductor run and a second conductor run disposed on the circuit board, wherein the first lead of the light emitting diode unit is electrically connected to the first conductor run and the second lead of the light emitting diode unit is electrically connected to the second conductor run.

12. The light fixture of claim 11, the housing comprises a thermally conductive material that is coated with a finish that inhibits the flow of electric current.

13. The light fixture of claim 11, wherein the reflective material is reflective tape.

14. The light fixture of claim 11, further comprising a copper ground plane disposed on top of the circuit board.

15. A light fixture comprising:

a housing having a top, and a bottom, the housing comprising;

a first side and a second side, the first side comprising an inner surface having a substantially straight portion, the second side comprising an inner surface having a substantially straight portion;

a crossbar attached to the substantially straight portion of the first side and to the substantially straight portion of the second side, the cross bar comprising an upper surface and a lower surface, wherein a mesa is defined on the upper surface, the mesa being substantially parallel to the straight portions of the first and second sides of the housing, wherein the upper surface of the crossbar faces the top of the housing and the lower surface of the crossbar faces the bottom of the housing;

a lens including a first end and a second end, the lens being formed with a downward fold at the first end and a downward fold at the second end, the lens being disposed on the top of the housing such that it acts as an end closure;

a cover disposed on the bottom of the housing, wherein the edges of the cover fold upward such that they are oriented in substantially the same direction as the first and second sides of the housing,

wherein the downward end folds of the lens of the housing are constrained by the upwardly folded edges of the cover;

a light emitting diode unit having a lens, a base portion, a first lead, and a second lead, wherein the base portion is attached to the mesa with a non-conductive adhesive;

a circuit board disposed on the upper surface of the crossbar; and

a first conductor run and a second conductor run disposed on the circuit board, wherein the first lead of the light emitting diode unit is electrically connected to the first conductor run and the second lead of the light emitting diode unit is electrically connected to the second conductor run.

16. The light fixture of claim 15, wherein the housing comprises a thermally conductive material that is coated with a finish that inhibits the flow of electric current.

17. A light fixture comprising:

a housing comprising;

a first side and a second side, the first side comprising an inner surface having a substantially straight portion, the second side comprising an inner surface having a substantially straight portion;

a crossbar attached to the substantially straight portion of the first side and to the substantially straight portion of the second side, the cross bar comprising an upper surface and a lower surface, wherein a mesa is defined on the upper surface, the mesa being substantially parallel to the straight portions of the first and second sides of the housing;

a light emitting diode unit having a lens, a base portion, a first lead, and a second lead, wherein the base portion is attached to the mesa with a non-conductive adhesive;

a circuit board disposed on the upper surface of the crossbar; and

a first conductor run and a second conductor run disposed on the circuit board, wherein the first lead of the light emitting diode unit is electrically connected to the first conductor run and the second lead of the light emitting diode unit is electrically connected to the second conductor run,

wherein the light emitting diode unit is one of a plurality of light emitting diode units, each of which has a base portion that is attached to the mesa with a non-conductive adhesive, each of which has respective first and second leads that are electrically connected to conductor runs.

18. A light fixture comprising:

a housing comprising;

a first side and a second side, the first side comprising an inner surface having a substantially straight portion, the second side comprising an inner surface having a substantially straight portion;

a crossbar attached to the substantially straight portion of the first side and to the substantially straight portion of the second side, the cross bar comprising an upper surface and a lower surface, wherein a mesa is defined on the upper surface, the mesa being substantially parallel to the straight portions of the first and second sides of the housing;

a light emitting diode unit having a lens, a base portion, a first lead, and a second lead, wherein the base portion is attached to the mesa with a non-conductive adhesive;

a first circuit board disposed on the upper surface of the crossbar;

a second circuit board disposed on the lower surface of the crossbar, the second circuit board having disposed thereon circuitry; and

a first conductor run and a second conductor run disposed on the circuit board, wherein the first lead of the light emitting diode unit is electrically connected to the first conductor run and the second lead of the light emitting diode unit is electrically connected to the second conductor run, wherein the first and second conductors are electrically connected to the circuitry, the circuitry controlling the intensity of the light emitted by the light emitting diode unit.

19. A light fixture comprising:

a housing comprising;

a first side and a second side, the first side comprising an inner surface having a substantially straight portion, the second side comprising an inner surface having a substantially straight portion;

a crossbar attached to the substantially straight portion of the first side and to the substantially straight portion of the second side, the cross bar comprising an upper surface and a lower surface, wherein a mesa is defined on the upper surface, the mesa being substantially parallel to the straight portions of the first and second sides of the housing;

a light emitting diode unit having a lens, a base portion, a first lead, and a second lead, wherein the base portion is attached to the mesa with a non-conductive adhesive;

a circuit board disposed on the upper surface of the crossbar; and

a first conductor run and a second conductor run disposed on the circuit board, wherein the first lead of the light emitting diode unit is electrically connected to the first conductor run and the second lead of the light emitting diode unit is electrically connected to the second conductor run,

wherein the inner surface of the first side of the housing has an upper angled portion and a lower angled portion, the substantially straight portion being located between the upper angled portion and the lower angled portion,

wherein the inner surface of the second side of the housing has an upper angled portion and a lower angled portion, the substantially straight portion being located between the upper angled portion and the lower angled portion, and

wherein the housing has a substantially H-shaped cross-section.

20. A light fixture comprising:

a housing comprising;

a first side, the first side comprising an inner surface and an outer surface, the inner surface of the first side having an upper angled portion, a lower angled portion, and a substantially straight portion disposed between the upper and lower angled portions, the outer surface having a plurality of fins,

a second side, the second side comprising an inner surface and an outer surface, the inner surface of the second side having an upper angled portion, a lower angled portion, and a substantially straight portion disposed between the upper and lower angled portions, the outer surface having a plurality of fins, wherein the first and second sides are oriented so that their respective inner surfaces face one another and are spaced apart at a distance,

a crossbar attached to the straight portion of the inner surface of the first side and to the straight portion of the inner surface of the second side such that the crossbar spans the distance, the crossbar having an upper surface with a mesa defined thereon, and a lower surface;

a lens formed with downward folds at its ends, the lens being disposed on the top of the housing such that it acts as an end closure;

a cover disposed on the bottom of the housing, wherein the edges of the cover fold upward such that they are oriented in substantially the same direction as the first and second sides of the housing, wherein the downward end folds of the lens of the housing are constrained by the upward end folds of the cover;

a first circuit board disposed on the upper surface of the crossbar, the first circuit board having a first conductor run and a second conductor run, wherein a ground plane disposed on an upper surface of the first circuit board, wherein mounting hardware connects the ground plane to a chassis, and wherein the first and second conductor runs are at least partly shielded from electromagnetic interference by the ground plane;

a light emitting diode unit that is attached to the mesa with a thin layer of adhesive material, the light emitting diode unit having a first lead and a second lead, the first lead being electrically connected to the first conductor run, the second lead being electrically connected to the second conductor run; and

a second circuit board disposed on the lower surface of the crossbar, the second circuit board having control circuitry that controls the intensity of the light emitting diode unit, wherein the first and second conductor runs are electrically connected to the control circuitry.