Magnetic field generator for a magnetic field measurement system

Patent metadata

Field	Value
Publication number	US-12007453-B2
Application number	US-202016862919-A
Country	US
Kind code	B2
Filing date	Apr 30, 2020
Priority date	May 3, 2019
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A magnetic field generator includes a plurality of conductive windings comprising a first conductive winding arranged in a first plane and a second conductive winding arranged in a second plane that is substantially parallel to the first plane. The plurality of conductive windings are configured to generate, when supplied with a drive current, a first component of a compensation magnetic field. The first component of the compensation magnetic field is configured to actively shield a magnetic field sensing region located between the first conductive winding and the second conductive winding from ambient background magnetic fields along a first axis that is substantially orthogonal to the first plane and the second plane.

First claim

What is claimed is:

1. A magnetic field generator comprising:
a plurality of conductive windings comprising:
a first conductive winding arranged in a first plane, and
a second conductive winding arranged in a second plane that is substantially parallel to the first plane,

wherein:
the plurality of conductive windings are configured to generate, when supplied with a drive current, a first component of a compensation magnetic field, the first component of the compensation magnetic field being configured to actively shield a magnetic field sensing region located between the first conductive winding and the second conductive winding from ambient background magnetic fields along a first axis that is substantially orthogonal to the first plane and the second plane;
a winding pattern of the first conductive winding includes a first counter-winding configured to reduce a spatial extent of a first fringe magnetic field generated by the first conductive winding; and
a winding pattern of the second conductive winding includes a second counter-winding configured to reduce a spatial extent of a second fringe magnetic field generated by the second conductive winding.

2. The magnetic field generator of claim 1 , wherein the first component of the compensation magnetic field is configured to actively shield the magnetic field sensing region by reducing or canceling a first component of the ambient background magnetic fields, the first component of the ambient background magnetic fields being along the first axis.

3. The magnetic field generator of claim 2 , wherein the first component of the compensation magnetic field is substantially equal and opposite to the first component of the ambient background magnetic fields.

4. The magnetic field generator of claim 1 , further comprising a planar substrate,
wherein the first conductive winding is arranged on a first surface of the planar substrate and the second conductive winding is arranged on a second surface of the planar substrate.

5. The magnetic field generator of claim 1 , further comprising a first planar substrate and a second planar substrate,
wherein the first conductive winding is arranged on a surface of the first planar substrate and the second conductive winding is arranged on a surface of the second planar substrate.

6. The magnetic field generator of claim 5 , wherein the surface of the first planar substrate and the surface of the second planar substrate both face the magnetic field sensing region.

7. The magnetic field generator of claim 5 , wherein the surface of the first planar substrate and the surface of the second planar substrate both face away from the magnetic field sensing region.

8. The magnetic field generator of claim 5 , wherein each of the first planar substrate and the second planar substrate comprises a printed circuit board.

9. The magnetic field generator of claim 1 , wherein:
the plurality of conductive windings further comprises:
a third conductive winding arranged in a third plane, and
a fourth conductive winding arranged in a fourth plane, and

the third plane and the fourth plane are substantially parallel to the first plane and the second plane.

10. The magnetic field generator of claim 9 , further comprising a first planar substrate and a second planar substrate,
wherein:
the first conductive winding is arranged on a first surface of the first planar substrate, the first surface of the first planar substrate facing away from the magnetic field sensing region,
the second conductive winding is arranged on a first surface of the second planar substrate, the first surface of the second planar substrate facing away from the magnetic field sensing region,
the third conductive winding is arranged on a second surface of the first planar substrate, the second surface of the first planar substrate facing the magnetic field sensing region, and
the fourth conductive winding is arranged on a second surface of the second planar substrate, the second surface of the second planar substrate facing the magnetic field sensing region.

11. The magnetic field generator of claim 10 , wherein winding patterns of the plurality of conductive windings are substantially identical.

12. The magnetic field generator of claim 10 , wherein:
winding patterns of the first conductive winding and the second conductive winding are substantially identical,
winding patterns of the third conductive winding and the fourth conductive winding are substantially identical, and
the winding patterns of the first conductive winding and the second conductive winding are different from the winding patterns of the third conductive winding and the fourth conductive winding.

13. The magnetic field generator of claim 10 , wherein:
a winding pattern of the first conductive winding is different from a winding pattern of the second conductive winding, and
winding patterns of the third conductive winding and the fourth conductive winding are substantially identical.

14. The magnetic field generator of claim 1 , wherein the first conductive winding and the second conductive winding are configured to be supplied with the same drive current.

15. The magnetic field generator of claim 1 , wherein the first conductive winding is configured to be supplied with a first drive current and the second conductive winding is configured to be supplied with a second drive current that is different from the first drive current.

16. The magnetic field generator of claim 15 , wherein the plurality of conductive windings are further configured to generate, when the first conductive winding is supplied with the first drive current and the second conductive winding is supplied with the second drive current, a first gradient component of the compensation magnetic field, the first gradient component of the compensation magnetic field being configured to actively shield the magnetic field sensing region from ambient background magnetic fields that linearly vary along the first axis.

17. The magnetic field generator of claim 1 , further comprising:
a first planar substrate;
a second planar substrate positioned opposite to the first planar substrate and separated from the first planar substrate by a gap, the magnetic field sensing region being located in the gap;
a first wiring set disposed on the first planar substrate;
a second wiring set disposed on the second planar substrate; and
one or more interconnects positioned between the first planar substrate and the second planar substrate and that electrically connect the first wiring set with the second wiring set to form a first continuous electrical path,
wherein the first continuous electrical path forms a third conductive winding configured to generate, when supplied with a first additional drive current, a second component of the compensation magnetic field configured to actively shield the magnetic field sensing region from the ambient background magnetic fields along a second axis that is substantially orthogonal to the first axis.

18. The magnetic field generator of claim 17 , wherein the first conductive winding is arranged on the first planar substrate and the second conductive winding is arranged on the second planar substrate.

19. The magnetic field generator of claim 17 , further comprising a third planar substrate and a fourth planar substrate,
wherein the first conductive winding is arranged on the third planar substrate and the second conductive winding is arranged on the fourth planar substrate.

20. The magnetic field

Assignees

• Hi Llc

Inventors

• Alford Jamu
• Henninger Michael
• Decker Dakota Blue
• Garber Stephen
• Gormley Jeffery Kang
• Homan Scott Michael
• Lasser Teague
• Ledbetter Micah
• Leung Jerry
• Mohseni Hooman
• Pratt Ethan
• Seidman Scott Jeremy
• Siepser Benjamin

Classifications

• H05K9/0071

  Active shielding · CPC title

• A61B5/6802

  Sensor mounted on worn items · CPC title

• G01R33/025

  Compensating stray fields {(G01R33/0017 takes precedence)} · CPC title

• H01F27/2866

  Combination of wires and sheets · CPC title

• A61B5/245

  specially adapted for magnetoencephalographic [MEG] signals · CPC title