System and Method for Reducing Effect of Magnetic Fields on a Magnetic Transducer

• US 20070126540A1
• Filed: 02/05/2007
• Published: 06/07/2007
• Est. Priority Date: 04/01/2002
• Status: Active Grant

• Current Assignee: Med El Elektromedizinische Geraete GmbH
• Original Assignee: Med El Elektromedizinische Geraete GmbH
• Inventors: Zimmerling, Martin
• Granted Patent: US 7,642,887 B2
• Time in Patent Office: Days
• US Class Current: 335/205
• 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 electromagnetic 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 electromagnetic transducer comprising:

a housing;

at least one coil associated with the housing; and

a plurality of magnets within the housing, the magnets aligned along an axis in an anti-parallel orientation, the magnets free to move along the axis, wherein vibration of the magnets causes vibration of the housing.

2. The electromagnetic 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 electromagnetic transducer according to claim 2, wherein the at least one biasing member is flexible and resilient.

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

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

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

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

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

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

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

11. The electromagnetic transducer according to claim 1, wherein the magnets include a first magnet having a first pole and a second magnet having a second pole, the first pole and the second pole having similar orientation, the first and second magnets aligned such that the first pole and the second pole are adjacent.

12. The electromagnetic transducer according to claim 1, wherein the magnets are cylindrical.

13. The electromagnetic 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.

14. The electromagnetic transducer according to claim 1, wherein the material is Teflon.

15. The electromagnetic transducer according to claim 1, wherein the friction of the magnet is reduced by a lubricant.

16. The electromagnetic 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.

17. The electromagnetic transducer according to claim 16, 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.

18. The electromagnetic transducer according to claim 1, wherein the housing is hermetically sealed.

19. The electromagnetic transducer according to claim 1, wherein the transducer is adapted to act as a sensor.

20. The electromagnetic transducer according to claim 19, wherein a vibration in the housing causes vibration in the magnets so as to cause a current in the at least one coil.

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

22. The electromagnetic 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.