Scanning endoscope

• US 20050020926A1
• Filed: 06/21/2004
• Published: 01/27/2005
• Est. Priority Date: 06/23/2003
• Status: Active Grant

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Tegreene, Clarence T., Wiklof, Christopher A., Lewis, John R., Xu, Jianhua, Reyerson, Christian S. L., Metting, Frank B. III, Amjad, Malik I.
• Granted Patent: US 7,448,995 B2
• Time in Patent Office: Days
• US Class Current: 600/476
• CPC Class Codes: A61B 1/00165 with light-conductive means, e.g. fibre optics A61B1/07 takes precedence
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00193 adapted for stereoscopic vision
• CPC Class Codes: A61B 1/045 Control thereof
• CPC Class Codes: A61B 1/0638 providing two or more wavelengths
• CPC Class Codes: A61B 1/0655 Control therefor
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: G02B 23/24 Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
• CPC Class Codes: G02B 23/2469 using optical fibres
• CPC Class Codes: G02B 23/26 using light guides for illumination G02B23/2469
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 27/0994 Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: H04N 23/17 using opto-mechanical scanning means only
• CPC Class Codes: H04N 23/555 for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• CPC Class Codes: H04N 23/56 provided with illuminating means

Abstract

A scanning endoscope, amenable to both rigid and flexible forms, scans a beam of light across a field-of-view, collects light scattered from the scanned beam, detects the scattered light, and produces an image. The endoscope may comprise one or more bodies housing a controller, light sources, and detectors; and a separable tip housing the scanning mechanism. The light sources may include laser emitters that combine their outputs into a polychromatic beam. Light may be emitted in ultraviolet or infrared wavelengths to produce a hyperspectral image. The detectors may be housed distally or at a proximal location with gathered light being transmitted thereto via optical fibers. A plurality of scanning elements may be combined to produce a stereoscopic image or other imaging modalities. The endoscope may include a lubricant delivery system to ease passage through body cavities and reduce trauma to the patient. The imaging components are especially compact, being comprised in some embodiments of a MEMS scanner and optical fibers, lending themselves to interstitial placement between other tip features such as working channels, irrigation ports, etc.

Claims

1. A scanned beam imager, comprising:

an illuminator operable to produce polarized light;

an illumination optical fiber having a proximal end and a distal end, the proximal end aligned to receive light from said illuminator, said illumination optical fiber being operable to transmit light from its proximal end to its distal end;

a scanner operable to direct light from the distal end of said illumination optical fiber across a field-of-view;

a polarizer cross-polarized to light from said illuminator;

at least one detection optical fiber, separate from said illumination optical fiber, said at least one detection fiber having distal and proximal ends, the distal end of said at least one detection fiber being positioned to receive at least a portion of the directed light from the field-of-view through said polarizer; and

at least one light detector positioned to receive light from the proximal end of said at least one detection optical fiber.

2. The scanned beam imager of claim 1, further comprising;

a beam shaping optical element operatively interposed between the distal end of said illumination optical fiber and said beam director.

3. The scanned beam imager of claim 2, wherein the characteristics of said beam shaping optical element are adjustable to vary the shape of the scanned light beam.

4. The scanned beam imager of claim 3, wherein the characteristics of said beam shaping optical element that are adjustable include a variable position of said beam shaping optical element.

5. The scanned beam imager of claim 3, wherein the characteristics of said beam shaping optical element that are adjustable include a variable shape of said beam shaping optical element.

6. The scanned beam imager of claim 1, further comprising;

at least one light gathering optical member positioned to gather light from the field-of-view and couple the gathered light into said at least one detection optical fiber.

7. The scanned beam imager of claim 6, wherein said at least one light gathering optical member comprises a substantially transparent plastic material.

8. The scanned beam imager of claim 1, wherein;

said at least one detection optical fiber comprises a plurality of detection optical fibers, and

said at least one light detector comprises a plurality of light detectors.

9. The scanned beam imager of claim 8, further comprising;

a plurality of filters coupled to said plurality of detection optical fibers, wherein each of said plurality of filters substantially prevents transmission of certain wavelengths of light to each of said plurality of light detectors.

10. The scanned beam imager of claim 1, wherein said at least one light detector comprises a plurality of light detectors, and wherein said scanned beam imager further comprises;

at least one wavelength separator for removing a portion of the light carried by said at least one detector optical fiber and directing the removed portion of light toward one of said plurality of light detectors.

11. The scanned beam imager of claim 10, wherein said wavelength separator comprises a dielectric mirror.

12. The scanned beam imager of claim 10, wherein said at least one wavelength separator is interposed between the proximal end of said at least one detector optical fiber and one of said plurality of light detectors.

13. The scanned beam imager of claim 1, wherein said beam director includes a mechanism operable to move the distal end of said illumination optical fiber.

14. The scanned beam imager of claim 1, wherein said beam director includes a moveable mirror aligned to receive light from the distal end of said illumination optical fiber and operable to deflect the light.

15. The scanned beam imager of claim 14, wherein said beam director includes a MEMS scanner.

16. A scanned beam endoscope, comprising:

a light emitter operable to produce polarized light;

an optical fiber operatively coupled to said light emitter for transmitting the light from a proximal to a distal location;

a scanner positioned to receive a light beam from the distal end of said optical fiber, said scanner being operatively coupled to scan the light beam over a field-of-view;

a polarizer cross-polarized to the light from said emitter and positioned to receive light from said field-of-view; and

at least one light detector positioned to receive light from the field-of-view through said polarizer.

17. The scanned beam endoscope of claim 16, wherein;

said at least one light detector comprises a plurality of light detectors.

18. The scanned beam endoscope of claim 17, further comprising;

a plurality of optical filters, each optical filter being optically coupled to one of said plurality of light detectors to substantially prevent transmission of one or more wavelengths of light from the field-of-view.

19. The scanned beam endoscope of claim 16, wherein;

said at least one light detector comprises a photodiode mounted near the distal end of said optical fiber, said photodiode modulating electrical signals responsive to light from the field-of-view incident thereon.

20. The scanned beam endoscope of claim 19, further comprising;

an analog-to-digital converter mounted near said photodiode, said analog-to-digital converter being operatively coupled to convert analog electrical signals produced by said photodiode to digital electrical signals for transmission to near the proximal end of said optical fiber.

21. A method for capturing and image, comprising:

creating a beam of light;

scanning the beam of light across a two-dimensional field-of-view at a rate non-constant in both axes;

collecting scattered light with one or more optical fibers; and

detecting light from the field-of-view.

22. The method for capturing an image of claim 21, further comprising sampling data at a substantially constant rate.

23. The method for capturing an image of claim 22, further comprising interpolating between the sampled data points to produce an image having substantially equal spacing between pixels.

24. The method for capturing an image of claim 21, wherein said step of scanning the beam of light, further comprises:

scanning along a first scan axis scanned at a first scan frequency; and

scanning along a second scan axis scanned at a second scan frequency;

wherein the second scan frequency is lower than the first scan frequency; and

wherein at least one of said axes is scanned at a sinusoidally varying scan speed.

25. The method for capturing an image of claim 24, wherein data is sampled at an instantaneous rate substantially inversely proportional to the instantaneous scan speed axis that is scanned at a sinusoidally varying scan speed.

26. The method for capturing an image of claim 24, wherein the instantaneous scan speed varies sinusoidally in both scan axes.

27. The method for capturing an image of claim 25, wherein both of said first and second scan axes are scanned at frequencies higher than the frame rate.

28. The method of claim 27, wherein the beam is scanned in a Lissajous scan pattern.

29. A scanned beam endoscope, comprising:

an illuminator that outputs a plurality of wavelengths;

an illumination optical fiber, coupled to said illuminator, having a proximal and a distal end;

a scanner resonant in two axes that receives light from the distal end of said illumination optical fiber and scans it across a field-of-view; and

a detector that receives light scattered by the field-of-view.

30. The scanned beam endoscope of claim 29, wherein said light having a plurality of wavelengths is broadband light.

31. The scanned beam endoscope of claim 29, wherein said light having a plurality of wavelengths is further comprised of a plurality of separate narrow band colors.

32. The scanned beam endoscope of claim 31, wherein there are three separate narrow band colors corresponding to red, green, and blue.

33. The scanned beam endoscope of claim 31, wherein at least one of the separate narrow band colors is in a region of the electromagnetic spectrum not readily distinguishable to the human eye.

34. A scanning endoscope tip, comprising:

an illumination optical fiber for receiving illumination light from a proximal separable body and transmitting the illumination light to a distal tip;

a scanner driven resonantly in at least two axes in said distal tip, positioned to receive the illumination light from the distal end of said illumination fiber and scan the illumination light across a field-of-view; and

one or more detection optical fibers positioned in said distal tip to receive light from the field-of-view and transmit the received light to a proximal end for transmission to the proximal separable body.

35. The scanning endoscope tip of claim 34, further comprising;

an outer sheath extending from a proximal to a distal position and carrying said optical fibers therein.

36. The scanning endoscope tip of claim 35, further comprising;

a plurality of electrical leads carried within said outer sheath having proximal ends for receiving electrical signals from the proximal separable body and transmitting the electrical signals to said scanner.

37. The scanning endoscope tip of claim 36, wherein one or more of said electrical leads further transmits signals from said distal end to said proximal end for transmission to the proximal separable body.

38. The scanning endoscope tip of claim 34, further comprising;

a tip connector attached to said proximal end of said optical fibers, said tip connector being removably coupleable to a body connector located on the separable body.

39. A scanned beam imager, comprising:

a plurality of beam scanners for scanning beams of light across a field-of-view; and

one or more non-imaging detector elements positioned to receive light from the field-of-view.

40. The scanned beam imager of claim 39, further comprising:

a separate source of illumination coupled to each of said plurality of beam scanners; and

one or more demultiplexers coupled to said one or more non-imaging detector elements for distinguishing between signals corresponding to said received light corresponding to each of the plurality of beam scanners.

41. The scanned beam imager of claim 40, wherein:

each of said separate sources of illumination outputs light modulated at a characteristic frequency; and

wherein said one or more demultiplexers separates the signals based upon frequency modulation.

42. The scanned beam imager of claim 40, wherein each of said separate sources of illumination outputs light at one or more characteristic wavelengths, and

wherein said one or more demultiplexers separates the signals based upon wavelength.

43. The scanned beam imager of claim 40, wherein there are two beam scanners;

and

the field-of-view of each beam scanner is substantially identical;

whereby said scanned beam imager produces a stereoscopic image.

44. An endoscope having a distal tip, comprising:

one or more lubricant dispensing orifices positioned near the distal tip, whereby lubricant may be dispensed to aid passage of the endoscope through body cavities.

49. The endoscope of claim 44, further comprising a coating on at least a portion of the distal tip that sheds lubricant, thus preserving a clear view and maximizing image quality.

45. The endoscope of claim 45, wherein the lubricant may be dispensed manually by a clinician.

46. The endoscope of claim 45, wherein the lubricant may be dispensed automatically.

47. The endoscope of claim 46, wherein the automatic lubricant dispensing may be triggered by image data.

48. The endoscope of claim 46, wherein the automatic lubricant dispensing may be triggered by tip angle.