Magnetically coupled lens actuator

• US 5,056,902 A
• Filed: 04/25/1990
• Issued: 10/15/1991
• Est. Priority Date: 04/25/1990
• Status: Expired due to Term

• Current Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith and Nephew Dyonics Inc (Smith & Nephew PLC)
• Inventors: Chinnock, Randal B., Dionne, Norman J.
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US07/514,119
• Time in Patent Office: 538 Days
• Field of Search: 350/574, 350/255, 350/582, 350/589, 350/518, 350/564, 350/DIG. 3, 128/4
• US Class Current: 359/503
• CPC Class Codes: A61B 1/00066 Proximal part of endoscope body, e.g. handles A61B1/0052 takes precedence
• CPC Class Codes: A61B 1/00188 with focusing or zooming features
• CPC Class Codes: A61B 34/73 Manipulators for magnetic surgery
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: Y10S 359/903 with magnet

Abstract

A lens surrounded by a protective chamber is focused by utilizing a magnetic field to adjust the position of the lens within the chamber. By using a magnetic field to adjust the lens position, it is not necessary to pass a mechanical device through the surface of the chamber, thereby allowing the chamber to be completely sealed to prevent contaminants from contacting the lens.

Claims

1. An apparatus for adjusting the position of a lens, comprising:

a sealed chamber surrounding said lens, said chamber including a window to permit light to enter said chamber and said lens;

an actuator held inside said chamber, said actuator being movable with respect to said chamber, said actuator being arranged to cause motion of said lens when said actuator is moved, said actuator having a plurality of projections that extend radially toward an inner surface of said chamber to provide a spacing between said actuator and said inner surface that is less at said projections than in a region of said actuator disposed between said projections; and

an element held outside said chamber and ferromagnetically coupled to at least some of said projections of said actuator through a surface of said chamber, said element being movable relative to said chamber to cause movement of said actuator to thereby adjust the position of said lens.

2. The apparatus of claim 1 wherein said actuator or said element comprises a magnet.

3. The apparatus of claim 1 wherein said actuator or said element define a closed flux path.

4. The apparatus of claim 3 wherein said projections define part of said flux path and are in sliding contact with said inner surface of said chamber.

7. The apparatus of claim 1 wherein said element comprises a magnet and a magnet support secured to said magnet, said magnet support including a stabilization member to restrict movement of said magnet.

8. The apparatus of claim 1 wherein said chamber is cylindrical.

9. The apparatus of claim 8 wherein said cylindrical chamber is sealed at each of its ends by a window through which said light may pass.

10. The apparatus of claim 8 wherein the curved surface of said cylindrical chamber is continuous and free of apertures through which debris or other contaminants could pass.

11. The apparatus of claim 1 wherein said apparatus further comprises a medical device.

12. The apparatus of claim 1 wherein said chamber is sealed such that motion cannot be transmitted mechanically through the wall of said chamber.

13. The apparatus of claim 1 wherein the surface of said chamber is continuous and free of apertures through which debris or other contaminants could pass.

14. The apparatus of claim 2 wherein said element is configured to be moved in a direction parallel to an axis of said chamber.

16. The apparatus of claim 2 wherein said magnet comprises a permanent magnet.

17. The apparatus of claim 1 wherein said chamber is non-magnetic.

18. The apparatus of claim 2 wherein said actuator is ferromagnetic.

19. The apparatus of claim 1 wherein said actuator comprises a magnet.

20. The apparatus of claim 1 wherein said lens is configured to move along an optical axis on which said lens lies.

62. The method of claim 1 wherein said actuator further comprises second radially extending projections each one of which is axially spaced from one of the first mentioned projections, said second projections being in sliding contact with said inner surface of said chamber.

63. The method of claim 62 wherein said second projections each has an axial extent that exceeds an axial extent of each of said first mentioned projections.

64. The method of claim 62 wherein said second projections provide a spacing between said actuator and said inner surface of said chamber that is less at said second projections than in regions of said actuator disposed between said second projections and said first mentioned projections.

5. An apparatus for adjusting the position of a lens, comprising:

a sealed chamber surrounding said lens, said chamber including a window to permit light to enter said chamber and said lens;

an actuator held inside said chamber, said actuator being movable with respect to said chamber, said actuator being arranged to cause motion of said lens when said actuator is moved;

an element comprising a magnet held outside said chamber and ferromagnetically coupled to said actuator through a surface of said chamber, said element being movable relative to said chamber to cause movement of said actuator to thereby adjust the position of said lens;

said actuator comprising projections which define part of a closed flux path between said actuator and said element, said projections being in sliding contact with an inner surface of said chamber; and

two ferromagnetic washers, respectively positioned adjacent the poles of said magnet and respectively aligned with said projections.

6. The apparatus of claim 5 wherein said washers are configured to conduct flux radially.

15. The apparatus of claim 5 wherein said magnet is ring-shaped.

21. An apparatus for adjusting the position of a lens along an optical axis on which the lens lies, comprising:

a cylindrical chamber surrounding said lens, said chamber being sealed in a manner that prevents motion from being transmitted mechanically through the wall of said chamber, said chamber including a window to permit light to enter said chamber and pass through said lens;

a ferromagnetic actuator held inside said chamber and supporting said lens, said actuator being movable with respect to said chamber to thereby cause motion of said lens, said actuator having a plurality of projections that extend radially toward an inner surface of said chamber to provide a spacing between said actuator and said inner surface that is less at said projections than in a region of said actuator disposed between said projections; and

a ring-shaped magnet surrounding said chamber and ferromagnetically coupled to at least some of said projections of said actuator via a surface of said chamber, said magnet being movable relative to said chamber to cause movement of said ferromagnetic actuator to thereby adjust the focus of said light passing through said lens.

24. The apparatus of claim 21 wherein said actuator defines a closed flux path.

25. The apparatus of claim 24 wherein said projections define part of said flux path and are in sliding contact with said inner surface of said chamber.

22. An endoscope coupler for coupling an endoscope to a viewing device, said coupler comprising:

a lens;

a sealed chamber surrounding said lens, said chamber including a window to permit light to enter said chamber and said lens;

an actuator held inside said chamber, said actuator being movable with respect to said chamber, said actuator being arranged to cause motion of said lens when said actuator is moved, said actuator having a plurality of projections that extend radially toward an inner surface of said chamber to provide a spacing between said actuator and said inner surface that is less at said projections than in a region of said actuator disposed between said projections; and

an element held outside said chamber and ferromagnetically coupled to at least some of said projections of said actuator through a surface of said chamber, said element being movable relative to said chamber to cause movement of said actuator to thereby adjust the position of said lens.

23. The apparatus of claim 22 wherein said actuator or said element comprises a magnet.

28. The apparatus of claim 22 wherein said element comprises a magnet and a magnet support secured to said magnet, said magnet support including a stabilization member to restrict movement of said magnet.

29. The apparatus of claim 22 wherein said chamber is cylindrical.

30. The apparatus of claim 29 wherein said cylindrical chamber is sealed at each of its ends by a window through which said light may pass.

31. The apparatus of claim 29 wherein the curved surface of said cylindrical chamber is continuous and free of apertures through which debris or other contaminants could pass.

32. The apparatus of claim 22 wherein said chamber is sealed such that motion cannot be transmitted mechanically through the wall of said chamber.

33. The apparatus of claim 22 wherein the surface of said chamber is continuous and free of apertures through which debris or other contaminants could pass.

34. The apparatus of claim 22 wherein said element is configured to be moved in a direction parallel to an axis of said chamber.

36. The apparatus of claim 23 wherein said magnet comprises a permanent magnet.

37. The apparatus of claim 22 wherein said chamber is non-magnetic.

38. The apparatus of claim 23 wherein said actuator is ferromagnetic.

39. The apparatus of claim 22 wherein said actuator comprises a magnet.

40. The apparatus of claim 22 wherein said lens is configured to move along an optical axis on which said lens lies.

26. An endoscope coupler for coupling an endoscope to a viewing device, said coupler comprising:

a lens;

a sealed chamber surrounding said lens, said chamber including a window to permit light to enter said chamber and said lens;

an actuator held inside said chamber, said actuator being movable with respect to said chamber, said actuator being arranged to cause motion of said lens when said actuator is moved;

an element comprising a magnet held outside said chamber and ferromagnetically coupled to said actuator through a surface of said chamber, said element being movable relative to said chamber to cause movement of said actuator to thereby adjust the position of said lens;

said actuator comprising projections which define part of a closed flux path between said actuator and said element, said projections being in sliding contact with an inner surface of said chamber; and

two ferromagnetic washers, respectively positioned adjacent to the poles of said magnet and respectively aligned with said projections.

27. The apparatus of claim 26 wherein said washers are configured to conduct flux radially.

35. The apparatus of claim 26 wherein said magnet is ring-shaped.

41. A method for moving a focusing lens having a chamber surrounding said lens, said chamber including a window to permit light to enter said chamber and said lens, said method comprising

providing an actuator positioned inside said chamber and arranged to cause motion of said lens when said actuator is moved, said actuator having a plurality of projections that extend radially toward an inner surface of said chamber to provide a spacing between said actuator and said inner surface that is less at said projections than in a region of said actuator disposed between said projection, and

moving an element that is ferromagnetically coupled to at least some of said projections of said actuator and positioned outside said chamber to cause said actuator to move thereby adjusting the position of said lens to adjust the focus of the light.

42. The method of claim 41 wherein said actuator or said element comprises a magnet.

43. The method of claim 41 wherein said actuator and said element define a closed flux path.

44. The method of claim 43 wherein said projections define part of said flux path and are in sliding contact with said inner surface of said chamber.

47. The method of claim 41 wherein said element comprises a magnet and a magnet support secured to said magnet, said magnet support including a stabilization member to restrict movement of said magnet.

48. The method of claim 41 wherein said chamber is cylindrical.

49. The method of claim 48 wherein said cylindrical chamber is sealed at each of its ends by a window through which said light may pass.

50. The method of claim 48 wherein the curved surface of said cylindrical chamber is continuous and free of apertures through which debris or other contaminants could pass.

51. The method of claim 41 wherein said lens is used to focus light from an endoscope.

52. The method of claim 41 wherein said chamber is sealed such that motion cannot be transmitted mechanically through the wall of said chamber.

53. The method of claim 41 wherein the surface of said chamber is continuous and free of apertures through which debris or other contaminants could pass.

54. The method of claim 42 wherein said element can be moved in a direction parallel to an axis of said chamber.

56. The method of claim 42 wherein said magnet comprises a permanent magnet.

57. The method of claim 41 wherein said chamber is non-magnetic.

58. The method of claim 42 wherein said actuator is ferromagnetic.

59. The method of claim 41 wherein said actuator comprises a magnet.

60. The method of claim 41 wherein said lens moves along an optical axis on which said lens lies.

45. A method for focusing a lens having a chamber surrounding said lens, said chamber including a window to permit light to enter said chamber and said lens, said method comprising

providing an actuator positioned outside said chamber and arranged to cause motion of said lens when said actuator is moved, said actuator comprising projections that are in sliding contact with an inner surface of said chamber, and

moving an element that is ferromagnetically coupled to said actuator through a closed flux path that includes said projections and positioned outside said chamber to cause said actuator to move thereby adjusting the position of said lens to adjust the focus of the light, said element comprising a magnet and wherein a ferromagnetic washer is positioned adjacent to each of the poles of said magnet, such that said washers are aligned with said projections.

46. The method of claim 45 wherein said washers conduct flux radially.

55. The method of claim 45 wherein said magnet is ring-shaped.

61. A method for focusing light transmitted from an endoscope to a viewing apparatus such as a camera, the light passing through a lens having a chamber surrounding said lens, said chamber including a window to permit light to enter said chamber and said lens, said method comprising

providing an actuator positioned inside said chamber and arranged to cause motion of said lens when said actuator is moved, said actuator having a plurality of projections that extend radially toward an inner surface of said chamber to provide a spacing between said actuator and said inner surface that is less at said projections than in a region of said actuator disposed between said projections, and

moving an element that is ferromagnetically coupled to at least some of said projections of said actuator and positioned outside said chamber to cause said actuator to move thereby adjusting the position of said lens to adjust the focus of the light.