Fiber optic laser illuminators

• US 4,011,403 A
• Filed: 03/30/1976
• Issued: 03/08/1977
• Est. Priority Date: 03/30/1976
• Status: Expired due to Term

• Current Assignee: Northwestern University
• Original Assignee: Northwestern University
• Inventors: Marhic, Michel E., Epstein, Max
• Primary Examiner(s): Richardson, Robert L.
• Application Number:
  US05/671,750
• Time in Patent Office: 343 Days
• Field of Search: 354/126, 178/7.1, 178/7.2, 178/DIG. 2, 350/96 R, 331/94.5 R, 331/94.5, 331/DIG. 1
• US Class Current: 348/370
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/4296 coupling with sources of high radiant energy, e.g. high power lasers, high temperature light sources
• 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: Y10S 385/901 Illuminating or display apparatus

Abstract

An object-illuminating and imaging system utilizing, in combination, a laser beam as a light source and an optical fiber as a light transmitter. Light-focusing means are provided and the focused laser beam is, in a preferred embodiment of the invention, directed to impinge upon a single, small-diameter optical fiber. Sensing means such as film or a television-type camera may be used visually to reproduce and/or display the illuminated object. A light-flow-disruptive means such as a vibrator, acting upon a collimated line of illumination, serves to reduce objectionable speckle effects ordinarily present in coherent light beams, thus providing enhanced clarity as viewed and in imaged reproductions.

Claims

1. Apparatus for providing laser illumination transmitting through an optical fiber for direct visualization of illuminated objects and for photographic recordation, said apparatus comprising

a highly concentrated light source including a laser beam having coherent light characteristics,

an optical fiber

focusing means for directing said laser beam to impinge on said fiber for transmission therealong, and

sensing means for visually reproducing objects illuminated by said laser beam.

2. The apparatus as set forth in claim 1 and further comprising light diffuser means interposed between said light source and objects illuminated thereby,

said diffuser means being operative to reduce speckle effects normally associated with coherent light characteristics of said laser beam.

3. The apparatus as set forth in claim 1 and further comprising vibrator means, and means operatively coupling said vibrator means to a light-carrying component of said apparatus whereby said vibrator means causes vibration of said light-carrying component so as effectively to reduce speckle effects normally associated with coherent light characteristics of said laser beam.

4. The apparatus as set forth in claim 1 wherein said sensing means is light-sensitive film.

5. The apparatus as set forth in claim 1 wherein said sensing means is a television type camera.

6. The apparatus as set forth in claim 1 wherein said laser beam constitutes a monochromatic light source.

7. Apparatus for providing white light laser illumination through an optical fiber for direct visualization of illuminated objects and for photographic recordation, said apparatus comprising

a highly concentrated light source including an ion laser,

mirror means in the laser,

means for balancing an output of said mirror means to provide simultaneous lasing at three different selectable wavelengths, thereby to produce a beam of coherent white light,

an optical fiber,

focusing means for directing said laser beam to impinge on said optical fiber for transmission therealong,

thereby to provide white light illumination for object visualization directly, for photographic recordation including recordation in color, and for visualization through imaging fiber optical systems.

8. The apparatus as set forth in claim 7 and further comprising gas pressure adjustment means for regulating gas pressure in said light source, a discharge current adjustment means, thereby to provide a balanced output of three colors to produce white light.

9. The apparatus as set forth in claim 7 wherein said optical fiber is a single fiber.

10. The apparatus as set forth in claim 7 and further comprising diffuser means interposed between said light source and objects illuminated thereby, said diffuser means being operative to reduce speckle effect associated with coherent white light, said diffuser means consisting essentially of a polytetrafluoroethylene disc.

11. The apparatus as set forth in claim 10 wherein said polytetrafluoroethylene disc has a thickness of about 0.25 mm.

12. The apparatus as set forth in claim 7 wherein said optical fiber is a fiber of about 85 μ

m in diameter and is constituted of an F-2 flint glass core and R6 soda lime cladding.

13. The apparatus as set forth in claim 7 and further comprising interference means for disrupting light emanating from said light source, thereby to reduce speckle effects ordinarily associated with a beam of coherent white light,

said interference means comprising vibrating means operatively coupled to said apparatus to effect vibrations in a collimating line of illumination projected from said ion laser through said optical fiber.

14. The apparatus as set forth in claim 13 and further comprising means coupling said vibrating means to said optical fiber for vibration thereof.

15. The apparatus as set forth in claim 13 wherein said vibration means is coupled to said focusing means to act thereon.

16. The apparatus as set forth in claim 13 wherein said vibrating means comprises an electro-mechanical device.

17. The apparatus as set forth in claim 13 wherein said vibrating means is a piezo electric device.

20. The apparatus as set forth in claim 9 wherein said fiber is a single fiber having a tapered configuration and decreasing continuously along a segment of its length from a larger to a smaller diameter.

21. The apparatus as set forth in claim 20 wherein the larger diameter is about 5 mm and the smaller diameter is about 50 μ

m.

18. The apparatus as set forth in calim 1 wherein said fiber is a single fiber having a tapered configuration and decreasing continuously along a segment of its length from a larger to a smaller diameter.

19. The apparatus as set forth in claim 18 wherein the larger diameter is about 5 mm and the smaller diameter is about 50 μ

m.