US2010163061A1PendingUtilityA1

Magnets with varying magnetization direction and method of making such magnets

56
Individually held — no corporate assignee on recordPriority: Apr 11, 2000Filed: Sep 28, 2009Published: Jul 1, 2010
Est. expiryApr 11, 2020(expired)· nominal 20-yr term from priority
Inventors:Francis M. Creighton
A61N 2/00Y10T29/4902H01F 41/028A61B 34/73H01F 13/003H01F 7/0294H01F 7/0278A61B 2034/731H01F 7/0273A61B 17/00
56
PatentIndex Score
0
Cited by
0
References
0
Claims

Abstract

A permanent magnet in which the magnetization direction varies with location to optimize or restrict a magnetic field property in a selected direction at a selected point. The magnetic field property may be, for example, the transverse magnetic field, axial magnetic field, axial gradient of the transverse magnetic field, transverse gradient of the transverse magnetic field, axis gradient of the axial magnetic field, transverse gradient of the axial magnetic field, the product of the transverse magnetic field and the transverse gradient of the transverse magnetic field, the product of the transverse magnetic field and the axial gradient of the transverse magnetic field, the product of the axial magnetic field and the transverse gradient of the axial magnetic field, or the product of the axial magnetic field and the axial gradient of the axial magnetic field. The magnet may be formed of one or more segments in which the magnetization direction varies smoothly and continuously, or the magnet may be formed of a plurality of segments in which the magnetization direction is constant. A method of making and using such magnets is also disclosed.

Claims

exact text as granted — not AI-modified
1 - 2 . (canceled) 
     
     
         3 . A permanent magnet in which the magnetization direction varies in three dimensions to restrict an undesired magnetic field property in a selected direction at a selected point. 
     
     
         4 . The permanent magnet in accordance with  claim 3  wherein the undesired magnetic field property is selected from transverse magnetic field, axial magnetic field, axial gradient of the transverse magnetic field, transverse gradient of the transverse magnetic field, axis gradient of the axial magnetic field, transverse gradient of the axial magnetic field, the product of the transverse magnetic field and the transverse gradient of the transverse magnetic field, the product of the transverse magnetic field and the axial gradient of the transverse magnetic field, the product of the axial magnetic field and the transverse gradient of the axial magnetic field, or the product of the axial magnetic field and the axial gradient of the axial magnetic field. 
     
     
         5 - 6 . (canceled) 
     
     
         7 . A permanent magnet in which the magnetization direction varies in three dimensions to restrict an undesired magnetic field property in a selected direction at a selected point. 
     
     
         8 . The permanent magnet in accordance with  claim 7  wherein the undesired magnetic field property is selected from transverse magnetic field, axial magnetic field, axial gradient of the transverse magnetic field, transverse gradient of the transverse magnetic field, axis gradient of the axial magnetic field, transverse gradient of the axial magnetic field, the product of the transverse magnetic field and the transverse gradient of the transverse magnetic field, the product of the transverse magnetic field and the axial gradient of the transverse magnetic field, the product of the axial magnetic field and the transverse gradient of the axial magnetic field, or the product of the axial magnetic field and the axial gradient of the axial magnetic field. 
     
     
         9 . (canceled) 
     
     
         10 . A method of performing a medical procedure using the magnet of  claim 3  to project a magnetic field into a patient to control a magnetic medical element inside the patient. 
     
     
         11 . (canceled) 
     
     
         12 . A method of making a permanent magnet in which the magnetization direction varies with location to restrict an undesired magnetic field property at a selected point in a selected direction, the method comprising: determining the desired shape, providing a blank of permanent magnetic material in the desired shape, and magnetizing the magnet to have a magnetization direction that varies in three dimensions so that the magnetization at each location in the magnet is in the direction that substantially restricts the undesired magnetic field property at a selected point in the selected direction. 
     
     
         13 . (canceled) 
     
     
         14 . A method of making a permanent magnet in which the magnetization direction varies with location to restrict an undesired magnetic field property at a selected point in a selected direction, the method comprising: determining the desired shape, providing a blank of permanent magnetic material in the desired shape, and magnetizing the magnet to have a magnetization direction that varies in two dimensions so that the magnetization at each location in the magnet is in the direction that substantially restricts the undesired magnetic field property at a selected point in the selected direction. 
     
     
         15 . (canceled) 
     
     
         16 . A method of making a permanent magnet in which the magnetization direction varies with location to restrict an undesired magnetic field property at a selected point in a selected direction, the method comprising determining the desired shape, assembling a plurality of permanent magnet segments into a shape substantially conforming to the desired shape, the magnetization direction of each permanent magnet segment varying in three dimensions so that the magnetization direction of each permanent magnet segment is in the direction that substantially restricts the undesired magnetic field property at a selected point in the selected direction. 
     
     
         17 . (canceled) 
     
     
         18 . A method of making a permanent magnet in which the magnetization direction varies with location to restrict an undesired magnetic field property at a selected point in a selected direction, the method comprising determining the desired shape, assembling a plurality of permanent magnet segments into a shape substantially conforming to the desired shape, the magnetization direction of each permanent magnet segment varying in two dimensions so that the magnetization direction of each permanent magnet segment is in the direction that substantially restricts the undesired magnetic field property at a selected point in the selected direction. 
     
     
         19 . The method according to  claim 18  wherein at least a portion of the surface of the magnet conforms to a surface of constant contribution to the desired magnetic field property at the selected location. 
     
     
         20 . The method according to  claim 18  wherein the direction of magnetization throughout each permanent magnet segment is constant. 
     
     
         21 . The method according to  claim 20  wherein the direction of magnetization throughout each permanent magnet segment is the direction which, at the center of mass of the segment, provides the maximum contribution to the desired property. 
     
     
         22 . The method according to  claim 20  wherein the direction of magnetization throughout each permanent magnet segment is the direction which, at the effective magnet center, provides the maximum contribution to the desired property. 
     
     
         23 . The method according to  claim 20  wherein the size and position of the permanent magnet segments is selected so that the difference in the direction of magnetization direction between adjacent magnet segments is less than about 45°. 
     
     
         24 . The method according to  claim 23  wherein the size and position of the permanent magnet segments is selected so that the difference in the direction of magnetization direction between adjacent magnet segments is less than about 30°. 
     
     
         25 . The method according to  claim 20  wherein the magnetization direction throughout each permanent magnet segment is not constant. 
     
     
         26 . The method according to  claim 20  wherein the desired magnetic field property is selected from transverse magnetic field, axial magnetic field, axial gradient of the transverse magnetic field, transverse gradient of the transverse magnetic field, axis gradient of the axial magnetic field, transverse gradient of the axial magnetic field, the product of the transverse magnetic field and the transverse gradient of the transverse magnetic field, the product of the transverse magnetic field and the axial gradient of the transverse magnetic field, the product of the axial magnetic field and the transverse gradient of the axial magnetic field, or the product of the axial magnetic field and the axial gradient of the axial magnetic field. 
     
     
         27 . The method according to  claim 20  wherein the desired property is transverse magnetic field is transverse magnetic field, and the relationship between the magnetization and angle the angular position is given by equation (3). 
     
     
         28 - 30 . (canceled)

Join the waitlist — get patent alerts

Track US2010163061A1 — get alerts on status changes and closely related new filings.

We store only your email — no account needed. See our privacy policy.