System and method for reducing effect of magnetic fields on a magnetic transducer

• US 7,642,887 B2
• Filed: 02/05/2007
• Issued: 01/05/2010
• Est. Priority Date: 04/01/2002
• Status: Expired due to Term

• Current Assignee: MED-EL Elektromedizinische Gerate GmbH (MED-EL Corporation)
• Original Assignee: MED-EL Elektromedizinische Gerate GmbH (MED-EL Corporation)
• Inventors: Zimmerling, Martin
• Primary Examiner(s): Barrera; Ramon M
• Application Number:
  US11/671,132
• Publication Number:
  US 20070126540A1
• Time in Patent Office: 1,065 Days
• Field of Search: 335229-234, 335302-306, 335205-207, 335/296, 73488-551, 73570-672, 600/12, 600/25, 607 55- 57
• US Class Current: 335/296
• CPC Class Codes: B06B 1/045 using vibrating magnet, armature or coil system
• CPC Class Codes: H01H 36/0073 actuated by relative movement between two magnets
• CPC Class Codes: H02K 33/16 with polarised armatures moving in alternate directions by reversal or energisation of a single coil system
• CPC Class Codes: H02K 35/02 with moving magnets and stationary coil systems
• CPC Class Codes: H04R 11/00 Transducers of moving-armature or moving-core type acoustic diaphragm of magnetisable material directly coacting with electromagnet H04R13/00
• CPC Class Codes: H04R 25/606 acting directly on the eardrum, the ossicles or the skull, e.g. mastoid, tooth, maxillary or mandibular bone, or mechanically stimulating the cochlea, e.g. at the oval window

Abstract

An electro-magnetic driver transducer free of torque in the presence of an external magnetic field, of any direction and orientation (such as in a Magnetic Resonance Imaging environment). The transducer includes a housing. At least one coil is associated with the housing. A plurality of magnets within the housing are aligned along an axis in an anti-parallel orientation. The magnets are free to move along an axis, wherein vibration of the magnets causes vibration of the housing. The transducer may be, for example, fixed to an ossicle.

Claims

1. An electro-magnetic transducer comprising:

a housing;

at least one coil associated with the housing; and

a plurality of spherical magnets within a single, undivided space in the housing, each spherical magnet within the housing aligned along an axis of rotational symmetry, the magnets free to rotate in any direction and to move within the housing along the axis, wherein vibration of the magnets causes vibration of the housing.

2. The electro-magnetic transducer according to claim 1, further comprising at least one biasing member positioned between one of the magnets and the housing, the biasing member for biasing movement of the magnets.

3. The electro-magnetic transducer according to claim 2, wherein the at least one biasing member is flexible and resilient.

4. The electro-magnetic transducer according to claim 2, wherein the at least one biasing member includes one of a spring and a silicone material.

5. The electro-magnetic transducer according to claim 2, wherein the at least one biasing member prevents the magnets from directly contacting the housing.

6. The electro-magnetic transducer according to claim 1, wherein the transducer is substantially free of torque in the presence of an external magnetic field.

7. The electro-magnetic transducer according to claim 6, wherein the external magnetic field is caused by a Magnetic Resonance Imaging device.

8. The electro-magnetic transducer according to claim 1, wherein the housing is adapted to be fixed to an ossicle.

9. The electro-magnetic transducer according to claim 1, wherein the at least one coil is positioned within the housing.

10. The electro-magnetic transducer according to claim 1, wherein the at least one coil is positioned external to the housing.

11. The electro-magnetic transducer according to claim 1, wherein at least one of the magnets and an inner wall of the housing are coated with a material having a low coefficient of friction.

12. The electro-magnetic transducer according to claim 11, wherein the material is Teflon.

13. The electro-magnetic transducer according to claim 1, wherein the friction of the spherical magnets is reduced by a lubricant.

14. The electro-magnetic transducer according to claim 1, wherein the at least one coil includes a plurality of coils, wherein the induced voltage of the plurality of coils arising from an external RF field is zero.

15. The electro-magnetic transducer according to claim 14, wherein the at least one coil includes a first and second outer coil, and a middle coil positioned between the first and second outer coils, wherein the middle coil is winded in a direction opposite the two outer coils, and wherein the number of loops of the middle coil equals the sum of loops of the first and second outer coils.

16. The electro-magnetic transducer according to claim 1, wherein the housing is hermetically sealed.

17. The electro-magnetic transducer according to claim 1, wherein the transducer is adapted to act as a sensor.

18. The electro-magnetic transducer according to claim 17, wherein a vibration in the housing causes vibration in the magnets so as to cause a current in the at least one coil.

19. The electro-magnetic transducer according to claim 1, wherein the transducer is adapted to act as an actuator.

20. The electro-magnetic transducer according to claim 19, wherein alternating current flowing through the at least one coil causes vibration of the magnets, the vibration transferred to the housing.

21. An electro-magnetic transducer comprising:

a housing;

at least one coil associated with the housing;

a plurality of spherical magnets within the housing, each spherical magnet within the housing aligned along an axis of rotational symmetry, the magnets free to rotate in any direction and to move within the housing along the axis, wherein vibration of the magnets causes vibration of the housing; and

at least one biasing member positioned between one of the magnets and the housing, the biasing member for biasing movement of the magnets and preventing the magnets from directly contacting the housing.

22. The electro-magnetic transducer according to claim 21, wherein the at least one biasing member is flexible and resilient.

23. The electro-magnetic transducer according to claim 21, wherein the at least one biasing member includes one of a spring and a silicone material.

24. The electro-magnetic transducer according to claim 21, wherein the transducer is substantially free of torque in the presence of an external magnetic field.

25. The electro-magnetic transducer according to claim 21, wherein at least one of the magnets and an inner wall of the housing are coated with a material having a low coefficient of friction.

26. The electro-magnetic transducer according to claim 21, wherein the at least one coil includes a plurality of coils, wherein the induced voltage of the plurality of coils arising from an external RF field is zero.

27. The electro-magnetic transducer according to claim 21, wherein a vibration in the housing causes vibration in the magnets so as to cause a current in the at least one coil.

28. The electro-magnetic transducer according to claim 21, wherein alternating current flowing through the at least one coil causes vibration of the magnets, the vibration transferred to the housing.

29. An electro-magnetic transducer comprising:

a housing;

a first and second outer coil, and a middle coil positioned between the first and second outer coils, the middle coil winded in a direction opposite the two outer coils, wherein the number of loops of the middle coil equals the sum of loops of the first and second outer coils, and wherein the induced voltage of the first, second and middle coils arising from an external RF field is zero; and

a plurality of spherical magnets within the housing, each spherical magnet in the housing aligned along an axis of rotational symmetry, the magnets free to rotate in any direction and to move within the housing along the axis, wherein vibration of the magnets causes vibration of the housing.

30. The electro-magnetic transducer according to claim 29, further comprising at least one biasing member positioned between one of the magnets and the housing, the biasing member for biasing movement of the magnets.

31. The electro-magnetic transducer according to claim 29, wherein the transducer is substantially free of torque in the presence of an external magnetic field.

32. The electro-magnetic transducer according to claim 29, wherein at least one of the magnets and an inner wall of the housing are coated with a material having a low coefficient of friction.

33. The electro-magnetic transducer according to claim 30, wherein a vibration in the housing causes vibration in the magnets so as to cause a current in the first, second and middle coils.

34. The electro-magnetic transducer according to claim 29, wherein alternating current flowing through the first, second, and middle coils cause vibration of the magnets, the vibration transferred to the housing.