Reducing effect of magnetic and electromagnetic fields on an implant's magnet and/or electronics

• US 7,091,806 B2
• Filed: 11/22/2004
• Issued: 08/15/2006
• Est. Priority Date: 04/01/2002
• Status: Expired due to Fees

• Current Assignee: MED-EL Elektromedizinische Gerate GmbH (MED-EL Corporation)
• Original Assignee: MED-EL Elektromedizinische Gerate GmbH (MED-EL Corporation)
• Inventors: Zimmerling, Martin, Hochmair, Erwin
• Primary Examiner(s): DONOVAN, LINCOLN D
• Application Number:
  US10/994,950
• Publication Number:
  US 20050062567A1
• Time in Patent Office: 631 Days
• Field of Search: 335205-207, 200/61.45 M, 200/404, 600/12
• US Class Current: 335/207
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: H01H 36/00 Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding
• CPC Class Codes: H01H 36/0073 actuated by relative movement between two magnets
• CPC Class Codes: H04L 12/1868 Measures taken after transmission, e.g. acknowledgments
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04W 4/14 Short messaging services, e.g. short message services [SMS] or unstructured supplementary service data [USSD]
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support

Abstract

An implantable magnet that can freely turn in response to an external magnetic field, thus avoiding torque and demagnetization on the implantable magnet. The implantable magnet can be combined with an electric switching function depending on the orientation of an external magnetic field, thus protecting an implanted coil and/or implant electronics against induction of over-voltage or performing an electric switching function for other various purposes. The magnetic switch may further include, for example, a first switching contact and a second switching contact. A magnetically soft body that includes an electrically conductive surface is shiftable between a first position where the body is in simultaneous contact with the first and second switching contacts, and a second position where the body is out of contact with at least one of the first and second switching contacts. The body and the implantable magnet are positioned such that the body is shifted to one of the first position and the second position as a function of the external magnetic field resulting in a magnetic force between the magnet and the magnetically soft body.

Claims

1. A magnetic switch comprising:

a first switching contact and a second switching contact;

a magnet free to rotate such that the magnet is capable of aligning at least partially with an external magnetic field; and

a magnetically soft body shiftable between a first position where the body is in simultaneous contact with the first and second switching contacts, and a second position where the body is out of contact with at least one of the first and second switching contacts, the body including an electrically conductive surface, the body and magnet positioned such that the body is shifted to one of the first position and the second position as a function of the external magnetic field resulting in a magnetic force between the magnet and the magnetically soft body.

2. The magnetic switch according to claim 1, wherein the magnet is a sphere.

3. The magnetic switch according to claim 1, wherein the magnetically soft body includes a calotte having a curvature that follows an adjacent surface of the magnet.

4. The magnetic switch according to claim 1, wherein the magnet is cylindrical.

5. The magnetic switch according to claim 4, wherein the magnetically soft body is a cuboid with a concave side that follows an adjacent surface of the magnet.

6. The magnetic switch according to claim 1, wherein the switch is enclosed in a housing.

7. The magnetic switch according to claim 6, wherein the housing is non-magnetic.

8. The magnetic switch according to claim 1, wherein the switch is hermetically encapsulated.

9. The magnetic switch according to claim 1, wherein the switch is used to switch between operating modes in an implant.

10. A cochlear implant comprising:

a first coil adapted to be electromagnetically coupled with a second coil of an external device; and

the switch of claim 1.

11. The implant according to claim 10, wherein the switch provides overvoltage protection as a function of an orientation of the external magnetic field.

12. The implant according to claim 10, wherein the switch is used to switch between operating modes of the implant.