Fiber bundle combiner and led illumination system and method

• US 6,290,382 B1
• Filed: 08/17/1998
• Issued: 09/18/2001
• Est. Priority Date: 08/17/1998
• Status: Expired due to Term

• Current Assignee: Datalogic Automation Incorporated (Datalogic S.p.A.)
• Original Assignee: PPT Vision, Inc. (Datalogic S.p.A.)
• Inventors: Lemaire, Charles A., Bourn, Charles T.
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Alavi, Ali
• Application Number:
  US09/135,394
• Time in Patent Office: 1,128 Days
• Field of Search: 362/551, 362/554, 362/555, 362/581, 362/11, 362/560, 362/580, 362/297, 362/294, 348/131, 356/394, 385/115
• US Class Current: 362/554
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G02B 6/40 having fibre bundle mating means
• CPC Class Codes: G02B 6/4201 Packages, e.g. shape, construction, internal or external details
• CPC Class Codes: G02B 6/4202 for coupling an active element with fibres without intermediate optical elements, e.g. fibres with plane ends, fibres with shaped ends, bundles
• CPC Class Codes: G02B 6/4203 Optical features
• CPC Class Codes: G02B 6/4212 the intermediate optical element being a coupling medium interposed therebetween, e.g. epoxy resin, refractive index matching material, index grease, matching liquid or gel
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball

Abstract

A fiber bundle combiner and LED illumination system and method. In one embodiment, an illumination fixture includes a plurality of light-emitting diode (LED) light sources, and a fiber-optic assembly having a common first bundle end and plurality of second ends. Each of the second ends is optically coupled to receive light from an LED. Ths fibers transmit light from the second ends to the common first end such that light from the LEDs is output at the first end. Optionally, pipe cells couple the light, wherein each LED is associated with a respective pipe cell that serves to focus light from the LED into one or more of the fibers. In one embodiment, each of the pipe cells includes a concave substantially spherical focussing reflective surface. Yet another aspect provides a method for making an LED and fiber-optic combiner assembly comprising: providing pipe cells, each pipe cell having an opening having a constriction for locating a fiber at a desired location within the pipe cell; inserting into each of the pipe cells one more more optical fibers; severing each of the optical fibers to form end at a desired position relative to the pipe cells; and assembling the plurality of pipe cells to a corresponding plurality of LEDs. In one embodiment, the severing operation includes melting the fibers to form a ball end on each fiber. In another embodiment, the assembling operation includes filling each of the pipe cells with liquid light-transmitting plastic.

Claims

1. An illumination fixture for illuminating an object at a machine-vision station comprising:

a plurality of light-emitting diode (LED) light sources;

a fiber-optic assembly having a common first bundle end and plurality of second ends, wherein the common first end comprises a bundled arrangement of first ends of individual optical fibers, and the second ends are optically coupled to receive light from the plurality of LEDs, and the second ends are in fiber-optic communication with the common first bundle end such that substantially all light in the fiber-optic assembly from the LEDs is output and leaves the fixture at the bundled first ends of individual fibers; and

a plurality of pipe cells, wherein each one of the plurality of LED light sources is associated with a respective pipe cell that serves to focus light from its LED light source into one or more of the fibers.

2. The illumination fixture according to claim 1, wherein each of the pipe cells includes a focussing reflective surface.

3. The illumination fixture according to claim 1, wherein each of the pipe cells includes a concave substantially spherical focussing reflective surface.

4. The illumination fixture according to claim 1, wherein each of the pipe cells includes a focussing lens that focusses light emitted from its LED on a fiber end.

6. The illumination fixture according to claim 1, wherein each of the pipe cells includes a substantially cylindrical interior reflective surface.

7. The illumination fixture according to claim 1, wherein each of the pipe cells includes an hourglass-shaped interior reflective surface.

8. The illumination fixture according to claim 1, wherein each of the pipe cells includes a substantially spherical interior reflective surface.

9. The illumination fixture according to claim 8, wherein each of the second fiber ends in the pipe cells includes a substantially spherical fiber-end surface.

10. The illumination fixture according to claim 1, wherein each of the pipe cells is filled with a light-transmissive material.

11. The illumination fixture according to claim 1, wherein each of the pipe cells is filled with a light-transmissive plastic.

12. The illumination fixture according to claim 1, wherein the plurality of LEDs are arranged in a plurality of rows, each row having a plurality of LEDs, and each of the pipe cells is part of one row of a plurality of separate rows of pipe cells, each row of pipe cells associated with one row of LEDs, such that each row of pipe cells can be assembled to a plurality of fibers, and then affixed to a row of LEDs.

5. An illumination system for illuminating an object at a machine-vision station comprising:

an illumination fixture including;

a substantially closed housing having a light-output terminal;

a plurality of light-emitting diode (LED) light sources within the housing; and

an internal fiber-optic assembly having a common first bundle end and plurality of second ends, each one of the second ends optically coupled to receive light from one of the plurality of LEDs, and all of the second ends in fiber-optic communication with the common first end, and the fiber-optic assembly held substantially within the housing such that light from the LEDs is output from the fixture at the first bundle end located at the light-output terminal, wherein each one of the second ends is a ball end formed by melting.

13. A method for illuminating an object at a machine-vision station, comprising:

(a) providing a first plurality of optical fibers each having a first end and a second end and a separate plurality of optical fibers each having a first end and a second end, wherein all of the first ends of the first plurality of optical fibers are grouped into a compact bundle end, and all of the first ends of the second plurality of optical fibers are grouped into a compact bundle end;

(b) emitting light from a plurality of LEDs onto the second ends individual ones of the first plurality of optical fibers;

(c) coupling light from the compact bundle end of the first plurality of optical fibers into the compact bundle end of the separate second plurality of optical fibers;

(d) emitting light from the second ends of the second plurality of optical fibers to the object at the machine-vision station; and

(e) imaging the light from the object into a machine-vision imaging device.

14. The method according to claim 13, further comprising optically coupling light from each one of the plurality of LEDs into one of the second ends of a corresponding one of the fibers.

15. The method according to claim 14, further comprising:

terminating each fiber at the first end of the first plurality of optical fibers at a common plane and terminating each fiber at the first end of the second plurality of optical fibers at a common plane.

16. The method according to claim 14, further comprising:

locating each fiber randomly within the bundle at the first end.

17. The method according to claim 14, further comprising focussing light from each LED into one or more of the fibers using a pipe cell, wherein each LED is associated with a respective pipe cell.

18. The method according to claim 17, wherein each of the pipe cells includes a focussing reflective surface.

19. The method according to claim 17, wherein each of the pipe cells includes a concave substantially spherical focussing reflective surface.

20. The method according to claim 17, wherein each of the pipe cells includes a focussinig lens that focusses light emitted from its LED on a fiber end.

21. The method according to claim 14, further comprising:

coupling light from the first bundle end of the first plurality of optical fibers into one of a plurality of interchangeably connected fiber-bundle head fixtures.

22. The method according to claim 14, further comprising

coupling heat from the plurality of LEDs to a heat sink.

23. A machine-vision system for obtaining information about an object at a machine-vision station, comprising:

an imaging device;

an image processor coupled to the imaging device; and

an illumination source coupled to the image processor, the illumination source comprising;

a plurality of light-emitting diode (LED) light sources;

a fiber-optic assembly having a common first bundle end and plurality of second ends, each one of the second ends optically coupled to receive light from one of the plurality of LEDs, and all of the second ends in fiber-optic communication with the common first end such that light from the LEDs is output at the first end;

a coupling unit attached to the first bundle end adapted to receive one of a plurality of interchangeably connected fiber-bundle head fixtures and to transmit light from the first bundle end output into one of the plurality of interchangeably connected fiber-bundle head fixtures; and

a fiber-bundle head fixture adapted transmit light received at the coupling unit to the object at the machine vision station.

24. The machine-vision system according to claim 23, wherein each fiber is randomly located within the bundle at the first end.

25. The machine-vision system according to claim 23, further comprising a plurality of pipe cells, wherein each LED is associated with a respective pipe cell that serves to focus light from the LED into one or more of the fibers.

26. The machine-vision system according to claim 23, wherein each of the pipe cells includes a concave focussing reflective surface.

27. The machine-vision system according to claim 26, wherein each of the pipe cells includes a focussing lens that focusses light emitted from its LED on a fiber end.