Lighting module assembly and method for a compact lighting device

• US 20070159819A1
• Filed: 01/10/2006
• Published: 07/12/2007
• Est. Priority Date: 01/10/2006
• Status: Active Grant

• Current Assignee: Bayco Products Incorporated
• Original Assignee: Bayco Products Ltd
• Inventors: Bayat, Bijan, Newton, James
• Granted Patent: US 7,281,820 B2
• Time in Patent Office: Days
• US Class Current: 362/236
• CPC Class Codes: F21L 4/02 characterised by the provision of two or more light sources
• CPC Class Codes: F21V 13/045 for portable lighting devices
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/75 with fins or blades having different shapes, thicknesses or spacing
• CPC Class Codes: F21V 29/76 with essentially identical parallel planar fins or blades, e.g. with comb-like cross-section
• CPC Class Codes: F21W 2111/02 for roads, paths or the like
• CPC Class Codes: F21W 2111/04 for waterways
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A plurality of compact light emitting assemblies is mounted on a frame configured as a heat sink that provides a structural platform and a thermal management component. The frame further ensures proper alignment of the light emitting devices to aim the individual light emitting assemblies in a direction that provides a predetermined overlap of the individual light beams resulting in a uniform, high brightness pattern on a target surface. The source of current connected to the light emitting devices may also be mounted on the frame. The compact light emitting module thus provided is readily adaptable to a variety of compact, high performance lighting product configurations.

Claims

1. A light emitting module, comprising:

a frame configured as a heat sink having first and second opposite sides, and a forward axis normal to the first side thereof; and

an array of a plurality N of light emitting assemblies connected to a source of current, wherein each light emitting assembly (LEA) is aligned at an optical axis and mounted on the first side of the frame configured as a heat sink such that the optical axes of each LEA diverge from one another and are disposed at a non-zero first predetermined angle relative to the forward axis.

2. The light emitting module (LEM) of claim 1, wherein:

each LEA comprises a light emitting device (LED) and a unitary lens-and-reflector having an optical axis oriented in a forward direction and configured for emitting light within a predetermined beam width angle in the direction of the forward axis.

3. The LEM of claim 1, wherein the first predetermined angle is in the range of 5+/−

3 degrees.

4. The LEM of claim 2, wherein the predetermined beam width angle is in the range of 40+/−

10 degrees.

5. The LEM of claim 2, wherein the ratio of twice the first predetermined angle to the second predetermined angle is approximately one-to-four.

6. The LEM of claim 1, comprising:

a light emitting drive circuit assembly attached to the second side of the frame configured as a heat sink for providing the source of current to the plurality N of LEAs.

7. The LEM of claim 1, wherein:

the first and second sides of the frame configured as a heat sink are substantially parallel and flat, irrespective of heat radiating surfaces disposed thereon, and perpendicular to the forward axis.

8. The LEM of claim 1, wherein:

the first and second sides of the frame configured as a heat sink are substantially parallel and perpendicular to the forward axis

9. The LEM of claim 8, wherein the shape of the curved frame configured as a heat sink is selected from the group consisting of cylindrical, spherical, and aspherical.

10. The LEM of claim 1, wherein at least one of the LEAs is mounted on the first side of the frame configured as a heat sink such that the optical axis of emission of the at least one of the LEAs is disposed at the same angle as the forward axis.

11. LEM of claim 10, wherein the optical axis of emission of the at least one of the LEAs is coincident with the forward axis.

12. The LEM of claim 1, wherein N is greater than or equal to two.

13. The LEM of claim 1, wherein N equals four.

14. The LEM of claim 3, wherein each LEA is mounted on and received by a seat formed in the first side of the frame configured as a heat sink to align the optical axis of the respective LEA at the first predetermined angle.

15. The LEM of claim 1, wherein the optical axes of emission of the plurality N of the LEAs diverge from each other.

16. The LEM of claim 3, wherein the optical axes of emission of the plurality N of the LEAs diverge from the forward axis and in a different direction from each other.

17. The light emitting module of claim 1, wherein the light emitted by each of the plurality of light emitting assemblies projects a substantially uniform beam of light for illuminating a target surface.

18. The light emitting module of claim 1, wherein the light emitted by the plurality of light emitting assemblies together project a composite beam of light that provides a substantially uniform pattern of light on a target surface.

19. The light emitting module of claim 18, wherein the pattern of light is generally circular upon a substantially flat surface oriented perpendicular to the forward axis of the light emitting module.

20. The light emitting module of claim 17, wherein the light emitted by the plurality of light emitting assemblies together project a composite beam of light comprised of individual beams, substantially circular in cross section, that overlap according to a predetermined configuration to provide the predetermined configuration as a pattern of light on a target surface.

21. The light emitting module of claim 1, wherein the frame comprises:

for each light emitting assembly, a mounting surface provided on the first side of the frame that is disposed at a 5+/−

3 degree angle relative to a plane coincident with the first side of the frame and perpendicular to the forward axis;

wherein

each such mounting surface is disposed in a direction facing away from any other mounting surface such that the optical axes of light emission of the light emitting assemblies mounted on the mounting surfaces diverge from each other.

22. The light emitting module of claim 1, wherein the frame comprises:

for each light emitting assembly, a mounting surface provided on the first side of the frame that is disposed at a 5+/−

3 degree angle relative to a plane perpendicular to the forward axis;

wherein

one or more of such mounting surfaces is disposed in a direction facing away from any other mounting surface such that the optical axis of light emission of the light emitting assembly mounted on the mounting surface does not diverge from at least one other light emitting assembly.

23. The light emitting module of claim 1, wherein a light emitting assembly comprises:

a unitary lens-and-reflector; and

a light emitting device (LED) situated at a radial center of a substantially hemispherical and transparent cap, the LED mounted on a substrate having a heat sink surface on a side opposite the LED;

wherein

the unitary lens-and-reflector includes a cylindrical, recessed port for receiving the substantially hemispherical and transparent cap therein such that the LED is located approximately at a focal point of the reflector portion of the unitary lens-and reflector.

24. The light emitting module of claim 23, wherein the unitary lens-and-reflector comprises:

an optical axis extending from an emission surface of an LED defining a forward direction of light emission and a plurality of refracting and reflecting elements disposed in sequence along the central axis for forming and directing a beam of light having a circular cross section and substantially uniform intensity throughout the cross section, into a predetermined angle of emission;

wherein

the unitary lens-and-reflector is formed of a solid, optical quality thermoplastic material.

25. The light emitting module of claim 24, wherein the unitary lens-and-reflector comprises:

an aspherical, cup-shaped reflecting surface providing total internal reflection of light emitted from a light source located at a focal point thereof along the optical axis and outside a critical angle relative to the optical axis; and

further enclosing

a spherical refracting surface disposed in the path of the reflected light, centered on and normal to the optical axis, concave in the forward direction of the reflected light and intersecting the aspherical reflecting surface equidistant from the optical axis around a perimeter of the spherical refracting surface; and

an aspherical refracting surface open toward the forward direction, disposed within the space enclosed within the aspherical reflecting surface and centered along the optical axis between the light source and the spherical refracting surface, for projecting light rays, emitted within the critical angle, in a diverging beam.

26. The light emitting module of claim 2, wherein the LED is a light emitting diode.

27. The light emitting module of claim 1, wherein first and second LEAs having a beam width angle of Q degrees are disposed at the first predetermined angle relative to the forward axis such that the total angle between the respective optical axes of the first and second LEAs is approximately one-fourth of the beam width angle Q of each first and second LEA when the respective first and second optical axes are disposed in a common plane with and diverging from the forward axis.

28. The light emitting module of claim 27, wherein:

each LEA comprises a light emitting device (LED) and a unitary lens-and-reflector having a optical axis oriented in a forward direction and configured for emitting light within the beam width angle Q.

29. The light emitting module of claim 27, wherein the beam width angle Q is approximately 40 degrees and the first predetermined angle is approximately 5 degrees.