MICROMAGNETOMETER OF THE FLUXGATE TYPE WITH IMPROVED EXCITATION COIL

• US 20070257669A1
• Filed: 04/30/2007
• Published: 11/08/2007
• Est. Priority Date: 05/04/2006
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: DELEVOYE, Elisabeth, JEANDEY, Christian
• Granted Patent: US 7,414,399 B2
• Time in Patent Office: Days
• US Class Current: 324/253
• CPC Class Codes: G01R 33/04 using the flux-gate principle

Abstract

The invention relates to a fluxgate micromagnetometer implemented in thin layers, fitted with at least one excitation coil with an arrangement and a structure that bring improvements particularly in terms of the magnetometer footprint, reduction in the “offsets” of measurements taken by the magnetometer, common mode rejection.

Claims

1. Micromagnetometer of the fluxgate type implemented in thin layers, including:

a support (100-101) having a given main plane,

a magnetic circuit fitted with at least one first magnetic core (102) of given main direction and at least one second magnetic core (104) parallel to the first core,

at least one excitation coil (110, 410) formed of a succession of conductive elements connected in series,

means for applying an excitation signal to said series of conductive elements,

the excitation coil comprising;

flat conductive zones (411, 412, 413, 414) parallel to each other extending in a direction that forms a non-zero angle with said given main direction and located respectively in a plane parallel to the main plane of the support, a first plurality of flat conductive zones (411, 413) being located opposite the first core, a second plurality of flat conductive zones (412, 414) being located opposite the second core, at least several conductive elements of the excitation coil being formed respectively;

of at least one first flat conductive zone (411) belonging to said second plurality of conductive zones connected to a second flat conductive zone (412) belonging to said first plurality of flat conductive zones and located in the same plane orthogonal to the main plane of the support as said second flat conductive zone, the conductive elements of the excitation coil being formed respectively;

of a conductive part implementing a closed contour surrounding the cores (102, 104), and including said first flat conductive zone (411) and said second flat conductive zone (412).

2. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, the conductive elements of the excitation coil being formed moreover respectively:

of a first conductive link (418) connected to said conductive part and intended to route a current coming from a previous conductive element of said series of conductive elements or means for applying the excitation signal,

of a second conductive link connected to said conductive part and intended to transmit a current to a next conductive element of said series of conductive elements or to the means for applying the excitation signal.

3. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, said flat conductive zones of said first plurality of flat conductive zones, and of said second plurality of flat conductive zones, being orientated along a direction orthogonal to said given main direction.

4. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, wherein said first flat conductive zone (411) and said second flat conductive zone (412) are located in a first plane parallel to the main plane of the support, said second flat conductive zone being connected and aligned with said first flat conductive zone.

5. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, said closed conductive contour additionally including:

a third flat conductive zone (413) and a fourth flat conductive zone (414) connected to, and aligned with, the third flat conductive zone, the third flat conductive zone and the fourth flat conductive zone being connected respectively to said first flat conductive zone (411) and to said second flat conductive zone (414) and being located in a second plane, parallel to the main plane of the support and such that the cores are placed between said first plane and said second plane.

6. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 5, said third flat conductive zone (413) and fourth flat conductive zone (414) being located in the same plane orthogonal to the main plane of the support as said first flat conductive zone (411) and second flat conductive zone (412).

7. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, said conductive part implementing a closed contour being formed of a first conductive portion partially surrounding the first core and a second conductive portion partially surrounding the second core, the first conductive portion and the second conductive portion being identical.

8. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, wherein the first conductive link (418) and the second conductive link (419) are located between the cores (102, 104) and orientated in a direction parallel to the given main direction, the second link and the first link being located respectively in a first plane parallel to the main plane of the support, and in a second plane, parallel to the main plane of the support and such that the cores are placed between the first plane and the second plane.

9. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, wherein the magnetic circuit additionally includes one or more other juxtaposed cores parallel to each other and to the first and second cores, several conductive elements of the excitation coil being formed moreover respectively:

of a plurality of flat conductive zones extending in a direction forming a non-zero angle with said given main direction and located in the same plane orthogonal to the main plane of the support as said first flat conductive zone and second flat conductive zone.

10. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, wherein the magnetic circuit additionally includes one or more other juxtaposed cores parallel to each other and to the first and second cores, said conductive part also surrounding said other cores.

11. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 1, additionally including at least one detection coil (420) wound around the cores (102, 104).

12. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 11, the detection coil (120, 520) and the excitation coil (110, 510) being interlaced.

13. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 11, the detection coil being formed of a succession of turns passing respectively alternately, opposite all the cores (102, 104) in a first plane parallel to the main plane of the support and opposite all the cores (102, 104) in a second plane parallel to the main plane of the support and such that the cores are located between the first plane and the second plane.

14. Micromagnetometer of the fluxgate type implemented in thin layers according to claim 11, wherein the detection coil is formed of a succession of conductive turns connected in series, a plurality of turns of the detection coil comprising respectively:

a plurality of flat conductive zones parallel to each other, located respectively opposite the cores of the magnetic circuit in a plane parallel to the main plane of the support and extending respectively in a direction forming a non-zero angle with said given main direction, the flat conductive zones of the detection coil (420) having a width (l′

c) larger than the width (1c) of the flat conductive zones of the excitation coil (410).

15. Device implemented in thin layers that includes:

a first micromagnetometer of the fluxgate type according to claim 1, fitted with cores orientated along a first main direction,

at least one second micromagnetometer of the fluxgate type according to claim 1, fitted with cores orientated along a second main direction orthogonal to said first main direction.