Magnetic sensor array

• US 20070163367A1
• Filed: 12/30/2005
• Published: 07/19/2007
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Inventors: Sherman, Jason, Popovic, Radivoje, DiSilvestro, Mark
• Granted Patent: US 7,525,309 B2
• Time in Patent Office: Days
• US Class Current: 73/866
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2068 using pointers, e.g. pointers having reference marks for determining coordinates of body points
• CPC Class Codes: A61B 2034/252 indicating steps of a surgical procedure
• CPC Class Codes: A61B 2034/256 having a database of accessory information, e.g. including context sensitive help or scientific articles
• CPC Class Codes: A61B 2090/3916 Bone tissue
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/4504 Bones A61B5/4547 takes precedence
• CPC Class Codes: A61B 5/4533 Ligaments
• CPC Class Codes: A61B 5/745 using a holographic display
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: G01R 33/0206 Three-component magnetometers
• CPC Class Codes: G01R 33/0354 SQUIDS

Abstract

A magnetic sensor array includes a first three-dimensional magnetic sensor secured to a substrate in a central location of the substrate. A number of second three-dimensional magnetic sensors are secured to the substrate at a first distance from the first magnetic sensor. Additionally, a number of one-dimensional magnetic sensors are secured to the substrate at a second distance from the first magnetic sensor greater than the first distance. Additional magnetic sensors of any dimension may also be included. The magnetic field sensitivity of the first and second three-dimensional magnetic sensors may be less than the magnetic field sensitivity of the one-dimensional magnetic sensors. The sensing range of the first and second three-dimensional magnetic sensors may be greater than the sensing range of the one-dimensional magnetic sensors. The magnetic sensor array may also include a processing circuit coupled to the magnetic sensors.

Claims

1. A magnetic sensor array for measuring a magnetic field generated by a magnetic source, the magnetic sensor array comprising:

a substrate,

a first three-dimensional magnetic sensor secured to the substrate at a central location;

a plurality of second three-dimensional magnetic sensors each secured to the substrate at a first distance from the first three-dimensional magnetic sensor; and

a plurality of first one-dimensional magnetic sensors each secured to the substrate at a second distance from the first magnetic sensor, the second distance being greater than the first distance.

2. The magnetic sensor array of claim 1, wherein each of the first one-dimensional magnetic sensors is configured to measure a Z-component of the three-dimensional magnetic flux density of the magnetic field at a point in space.

3. The magnetic sensor array of claim 2, further comprising a plurality of second one-dimensional magnetic sensors each secured to the substrate at a third distance from the first magnetic sensor and configured to measure a Z-component of the three-dimensional magnetic flux density of the magnetic field at a point in space, the third distance being greater than the second distance.

4. The magnetic sensor array of claim 3, further comprising a plurality of third one-dimensional magnetic sensors each secured to the substrate at a fourth distance from the first magnetic sensor, a first number of the plurality of third one-dimensional magnetic sensors are configured to measure an X-component of the three-dimensional magnetic flux density of the magnetic field at a point in space and a second number of the plurality of the third one-dimensional magnetic sensors are configured to measure a Y-component of the three-dimensional magnetic flux density of the magnetic field at a point in space, the fourth distance being greater than the third distance.

5. The magnetic sensor array of claim 4, wherein each of the first and second magnetic sensors has a lower magnetic field sensitivity and a greater sensing range than each of the third, fourth, and fifth magnetic sensors.

6. The magnetic sensor array of claim 1, wherein a first number of the plurality of first one-dimensional magnetic sensors are configured to measure an X-component of the three-dimensional magnetic flux density of the magnetic field at a point in space and a second number of the plurality of the third magnetic sensors are configured to measure a Y-component of the three-dimensional magnetic flux density of the magnetic field at a point in space.

7. The magnetic sensor array of claim 1, wherein the first three-dimensional magnetic sensor has a lower magnetic field sensitivity and a greater sensing range than each of the first one-dimensional magnetic sensors.

8. The magnetic sensor array of claim 7, wherein each of second three-dimensional magnetic sensors has a lower magnetic field sensitivity and a greater sensing range than each of the first one-dimensional magnetic sensors.

9. The magnetic sensor array of claim 1, wherein the substrate is formed from an FR4 material.

10. The magnetic sensor array of claim 1, further comprising a processing circuit electrically coupled to each of the first three-dimensional magnetic sensor, the second three-dimensional magnetic sensors, and the third one-dimensional magnetic sensors.

11. The magnetic sensor array of claim 10, further comprising a third three-dimensional magnetic sensor spaced apart from the sensor board and electrically coupled to the processing circuit.

12. The magnetic sensor array of claim 11, wherein the third three-dimensional magnetic sensor is configured to measure at least one environmental magnetic field.

13. The magnetic sensor array of claim 11, wherein the processing circuit is configured to compensate output signals of at least one of the first three-dimensional magnetic sensor, the second three-dimensional magnetic sensors, and the first one-dimensional magnetic sensors based on an output of the third three-dimensional magnetic sensor.

14. The magnetic sensor array of claim 11, wherein the processing circuit is configured to compensate output signals of at least one of the first three-dimensional magnetic sensor, the second three-dimensional magnetic sensors, and the first one-dimensional magnetic sensors based on an offset voltage produced by the at least one of the first three-dimensional magnetic sensor, the second three-dimensional magnetic sensors, and the first one-dimensional magnetic sensors.

15. The magnetic sensor array of claim 1, wherein the plurality of the second three-dimensional magnetic sensors and the plurality of the first one-dimensional magnetic sensors are circumferentially spaced around the first three-dimensional magnetic sensor.

16. An apparatus for measuring a magnetic field of a magnetic source, the magnetic field being defined by a three-dimensional magnetic flux density at a plurality of points in space, the apparatus comprising:

a housing;

a substrate coupled to the housing;

a first three-dimensional magnetic sensor coupled to the substrate and configured to measure an X-component, a Y-component, and a Z-component of the three dimensional magnetic flux at a point in space;

a plurality of second three-dimensional magnetic sensors coupled to the substrate a first distance from the first three-dimensional magnetic sensor, each of the plurality of second three-dimensional magnetic sensors being configured to measure the X-component, the Y-component, and the Z-component of the three dimensional magnetic flux at a point in space;

a plurality of first one-dimensional magnetic sensors coupled to the substrate a second distance from the first three-dimensional magnetic sensor greater than the first distance, each of the plurality of first one-dimensional magnetic sensors being configured to measure the Z-component of the three-dimensional magnetic flux density at a point in space;

a plurality of second one-dimensional magnetic sensors coupled to the substrate a third distance from the first three-dimensional magnetic sensor greater than the second distance, each of the plurality of second one-dimensional magnetic sensors being configured to measure the Z-component of the three-dimensional magnetic flux density at a point in space; and

a plurality of third one-dimensional magnetic sensors coupled to the substrate a fourth distance from the first three-dimensional magnetic sensor greater than the third distance, a first number of the plurality of third one-dimensional magnetic sensors being configured to measure the X-component of the three-dimensional magnetic flux density at a point in space and a second number of the plurality of third one-dimensional magnetic sensors being configured to measure the Y-component of the three-dimensional magnetic flux density at a point in space.

17. The apparatus of claim 16, wherein each of the first three-dimensional magnetic sensor, the second three-dimensional magnetic sensors, the first one-dimensional magnetic sensors, and the second one-dimensional magnetic sensors is coupled to a top surface of the substrate.

18. The apparatus of claim 17, wherein each of the plurality of third one-dimensional magnetic sensors is positioned substantially orthogonally to the top surface of the substrate.

19. The apparatus of claim 16, wherein (i) the magnetic field sensitivity of each of the first and second three-dimensional magnetic sensors is less than the magnetic field sensitivity of each of the first, second, and third one-dimensional magnetic sensors and (ii) the sensing range of each of the first and second three-dimensional magnetic sensors is less than the sensing range of each of the first, second, and third one-dimensional magnetic sensors.

20. A magnetic sensor array for measuring a magnetic field generated by a magnetic source coupled to a bone of a patient, the magnetic sensor array comprising a first number of magnetic sensors each secured to a substrate at a first distance from a center point of the substrate and a second number of magnetic sensors each secured to the substrate at a second distance greater than the first distance from the center point, wherein the magnetic field sensitivity of each of the first number of magnetic sensors is less than the magnetic field sensitivity of each of the second number of magnetic sensors and the sensing range of each of the first number of magnetic sensors is greater than the sensing range of each of the second number of magnetic sensors.