Zoom spotlight using LED array

• US 8,979,316 B2
• Filed: 08/23/2011
• Issued: 03/17/2015
• Est. Priority Date: 05/11/2011
• Status: Active Grant

• Current Assignee: DiCon Fiber Optics Incorporated
• Original Assignee: DiCon Fiber Optics Incorporated
• Inventors: Lee, Jeffrey B., Chiang, Brian I-Yuan, Ho, Han-Kun
• Primary Examiner(s): Payne, Sharon
• Assistant Examiner(s): Sokolowski, Kenny C
• Application Number:
  US13/216,085
• Publication Number:
  US 20120287621A1
• Time in Patent Office: 1,302 Days
• Field of Search: 362/249.02, 362/311.02, 362/800, 362/268, 362/306, 362/307, 362/310, 362/372, 362/373, 362/331, 362/355
• US Class Current: 362/268
• CPC Class Codes: F21V 11/16 using sheets without apertures, e.g. fixed
• CPC Class Codes: F21V 13/14 the elements being filters or photoluminescent elements, reflectors and refractors
• CPC Class Codes: F21V 14/06 by movement of refractors in vehicle head lamps F21S41/635
• CPC Class Codes: F21V 23/04 the elements being switches safety devices F21V25/00
• CPC Class Codes: F21V 5/008 Combination of two or more successive refractors along an optical axis
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21W 2131/406 for theatres, stages or film studios
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: H05B 45/3574 Emulating the electrical or functional characteristics of incandescent lamps

Abstract

A LED array spot illuminator for providing light along an optical axis comprises a substrate and at least one array of multiple LED chips without individual packaging supported by the substrate, wherein the LED chips emit light within the same or different wavelength ranges and are distributed laterally with respect to the axis over a light-emitting area. The LED chips have light emitting surfaces for emitting light in directions transverse to the area. An optical device collects and directs light emitted by the LED chips of the at least one array along the axis. An aperture passes the light emitted by the LED chips of the at least one array along the axis, wherein light collected by the optical device and passed by the aperture forms a beam of light illuminating a spot. Electric current is supplied to the multiple LED chips, causing them to emit light. Light emitted by the multiple LED chips that passed through the optical device and the aperture form a beam of light illuminating a spot. A distance between the multiple LED chips and one or more elements of the optical device is controlled to select a size of the spot.

Claims

1. A LED array spot illuminator for providing light along an optical axis to illuminate a spot, comprising:

a substrate;

at least one array of multiple LED chips without individual packaging supported by said substrate, wherein the LED chips emit light within different wavelength ranges and are distributed laterally with respect to said axis over a light-emitting area, said LED chips having light emitting surfaces for emitting light in directions transverse to said area, wherein the dimensions of the light-emitting area do not exceed 25 mm;

an optical element adjacent to the light emitting surfaces of the LED chips in said at least one array and in the optical axis collecting light emitted by the LED chips;

an optical device that collects and directs light emitted by the LED chips of the at least one array and collected by said optical element to output light illuminating the spot in directions within a cone angle from and along said axis, said optical device including one or more lenses;

an aperture located in the optical axis between the optical element and the optical device passing the light emitted by the LED chips of the at least one array along said axis, wherein light collected by said optical element and said optical device and passed by the aperture forms a beam of light illuminating the spot, defining a boundary for and shape of the spot;

a diffusing/scattering/homogenizing element located in a path of the beam between the at least one array of multiple LED chips and the aperture so that the beam illuminating the spot is substantially spectrally uniform, across the illuminated spot; and

an instrument for adjusting a distance between the optical element and at least one of the one or more lenses to adjust said cone angle, to select the size of the illuminated spot, and to define a sharp boundary for the spot.

2. The illuminator of claim 1, wherein the light-emitting area of the array of LED chips is substantially circular in shape.

3. The illuminator of claim 1, wherein the illuminated spot is substantially uniform in intensity across the illuminated spot.

4. The illuminator of claim 1, said optical device comprising a first collector lens for collecting light from the optical element and a second lens focusing or collimating light from the collector lens to form the beam directed to the illuminated spot.

5. The illuminator of claim 4, wherein a distance between the substrate and the second lens is in a range of about 6 to 12 inches.

6. The illuminator of claim 1, said optical device comprising three lenses forming a zoom system, wherein said aperture is located at an object plane of a first lens of the three lenses that is closest to the aperture.

7. The illuminator of claim 6, said instrument adjusting one or more distances between the first lens and the remaining two of the three lenses to alter the effective focal length of the zoom system and the cone angle.

8. The illuminator of claim 7, the instrument adjusting the one or more distances between the remaining two of the three lenses and the first lens synchronously, or a position of only one of the remaining two of the three lenses relative to the light emitting surfaces of the LED chips.

9. The illuminator of claim 1, further comprising an index matching material between the light emitting surfaces of the LED chips in said at least one array and the optical element.

10. The illuminator of claim 1, the LED chips emitting light within the different wavelength ranges emit light at substantially uniform brightness levels across the spot.

11. The illuminator of claim 1, wherein the optical element comprises a half-ball lens.

12. The illuminator of claim 1, further comprising a reflective surface located between the optical element and the aperture reflecting light emitted by the plurality of LED chips towards the aperture, wherein the aperture passes only a central portion of the beam from the LED chips and the reflector to enhance spectral uniformity of the beam at the spot.

13. The illuminator of claim 1, wherein said at least one array of multiple LED chips comprises multiple strings of LED chips, each string emitting light in a wavelength range different from the wavelength range of light emitted by a different string in the at least one array.

14. The illuminator of claim 13, wherein a spacing between adjacent LED chips in said at least one array is about 0.1 mm.

15. The illuminator of claim 1, further comprising an electronic control circuit for supplying separate electric currents to the multiple strings of LED chips, and at least one interface for receiving computer or user commands for controlling the electric currents supplied by the circuit to control light emission by the multiple LED chips, for varying either the color or color temperature of the substantially spectrally uniform illuminated spot, as well as the overall intensity of the spot.

16. The illuminator of claim 1, further comprising a heat sink in thermal communication with the multiple LED chips.

17. The illuminator of claim 1, wherein a spacing between adjacent LED chips in said at least one array is in a range of about 0.05 to 0.2 mm.

18. The illuminator of claim 1, wherein the multiple LED chips without individual packaging in said at least one array have dimensions in a range of about 0.5 to 2 mm.

19. The illuminator of claim 18, wherein the multiple LED chips without individual packaging in said at least one array have dimensions of about 1 mm by 1 mm.

20. The illuminator of claim 1, wherein light of substantially uniform brightness is provided within said cone angle set by factors including size of said aperture and an optical arrangement including said optical element.

21. The illuminator of claim 1, wherein the diffusing/scattering/homogenizing element is located at or near an object plane of the optical device.

22. The illuminator of claim 1, wherein the array contains at least 9 LED chips and the LED chips of the array are arranged to occupy an area substantially circular in shape with a diameter from approximately 8 to 25 mm.

23. The illuminator of claim 1, further comprising phosphor on some or all of the LED chips.

24. The illuminator of claim 1, said array including LED chips that emit red, blue and green light, so that the LED chips emit mixed/blended light of any color, including white light of varying color temperatures.

25. The illuminator of claim 1, wherein a shape of the aperture is chosen to define the shape of the illuminated spot.

26. The illuminator of claim 1, further comprising a rotatable wheel with filter(s) or different shaped apertures for selecting a color or shape or size of the beam of light.

27. The illuminator of claim 1, said different wavelength ranges including red, blue and green wavelengths, and wherein the relative blend of red, blue and green wavelengths is substantially the same within the beam of light.

28. The illuminator of claim 1, wherein the relative blend of the different wavelengths is substantially the same within the beam of light.

29. A method for providing light that forms a beam along an optical axis for illuminating a spot, comprising:

providing a LED array illuminator that includes a substrate, at least one array of multiple LED chips without individual packaging supported by said substrate, wherein the LED chips emit light within different wavelength ranges and are distributed laterally with respect to said axis, said at least one array occupying a light-emitting area whose dimensions do not exceed 25 mm;

supplying electric current to the multiple LED chips, causing them to emit light;

collecting light emitted by the LED chips using an optical element adjacent to the light emitting surfaces of the LED chips in said at least one array;

passing the collected light emitted by the multiple LED chips through an aperture;

passing light emitted by the multiple LED chips to an optical device, so that light emitted by the multiple LED chips that passed through the optical device and the aperture are in directions within a cone angle from and along said axis, forming a beam of light illuminating a the spot and defining a boundary for and shape of the spot;

causing light in the beam to be modified before the beam passes through the aperture by a diffusing/scattering/homogenizing element so that the beam illuminating the spot is substantially spectrally uniform across the illuminated spot; and

controlling a distance between the optical element and one or more elements of the optical device to adjust said cone angle, to select a size of the spot and to define a sharp boundary for-the spot.

30. The method of claim 29, said different wavelength ranges including red, blue and green wavelengths, and wherein the relative blend of red, blue and green wavelengths is substantially the same within the beam of light.

31. The method of claim 29, wherein the relative blend of the different wavelengths is substantially the same within the beam of light.