Magnetic field sensor

• US 6,317,048 B1
• Filed: 09/15/2000
• Issued: 11/13/2001
• Est. Priority Date: 09/16/1999
• Status: Expired due to Fees

• Current Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Bomya, Timothy J., Riggs, Alan J.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): LA, ANH V
• Application Number:
  US09/662,742
• Time in Patent Office: 424 Days
• Field of Search: 340/540, 340/547, 340/667, 340/436, 340/435, 340/438, 340/545.1, 340/545.2, 340/430, 340/573.1, 340/551, 340/941, 340/933, 340/686.2, 340/686.6, 340/686.5, 180/274, 180/282, 280/735, 307/10.71, 324/212, 324/252, 73/351.2
• US Class Current: 340/573.1
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: B60R 21/0134 responsive to imminent contact with an obstacle , e.g. using radar systems
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558
• CPC Class Codes: B60R 21/01534 using electromagneticwaves, e.g. infrared
• CPC Class Codes: B60R 21/01538 for image processing, e.g. cameras or sensor arrays
• CPC Class Codes: G01R 33/10 Plotting field distribution ; Measuring field distribution
• CPC Class Codes: G01V 3/081 the magnetic field is produced by the objects or geological structures characterised by the method of magnetic field measurement G01R33/00
• CPC Class Codes: G08G 1/042 using inductive or magnetic detectors

Abstract

A magnetic field sensor comprising a plurality of magnetic sensing elements and a means for generating an image signal from the plurality of the signals generated thereby is used i) to sense a magnetic field proximate to a body portion of a vehicle for adjusting a magnetic circuit thereof, ii) to sense an occupant in a seat of a vehicle, or iii) to sense from within a body portion of a vehicle magnetic-field-influencing objects proximate thereto. In another aspect, the magnetic field sensor further comprises a plurality of magnetic focusing elements proximate to the magnetic sensing elements for improving the clarity of the magnetic image.

Claims

1. A method of forming and using a magnetic image of a body portion of a vehicle, comprising:

a. sensing a magnetic field at a plurality of locations proximate to said body portion so as to generate a plurality of signals, wherein each signal of said plurality of signals is responsive to a magnetic field strength at one of said plurality of locations;

b. generating an image signal from said plurality of signals; and

c. using a magnetic image from said image signal to adjust a magnetic circuit containing said body portion.

2. A method of forming and using a magnetic image of a body portion of a vehicle as recited in claim 1, wherein said plurality of locations comprise a one-dimensional array of locations, further comprising:

a. translating said one-dimensional array of locations in a direction that is transverse to said one-dimensional array;

b. repeating said operation of sensing a magnetic field at a resulting plurality of locations after said operation of translating; and

c. performing said operations of translating and repeating at least once.

3. A method of forming and using a magnetic image of a body portion of a vehicle as recited in claim 1, wherein said plurality of locations comprise a two-dimensional array of locations.

4. A method of forming and using a magnetic image of a body portion of a vehicle as recited in claim 1, wherein the operation of using said magnetic image to adjust a magnetic circuit comprises locating an element within said body portion, wherein said element is part of a magnetic sensor incorporating said body portion of said vehicle and said element is selected from a magnetic sensing element, a coil, and a ferromagnetic element.

5. A method of forming and using a magnetic image from a body portion of a vehicle, comprising:

a. sensing a magnetic field at a plurality of locations from within said body portion so as to generate a plurality of signals, wherein each signal of said plurality of signals is responsive to a magnetic field strength at one of said plurality of locations;

b. generating an image signal from said plurality of signals; and

c. detecting from said image signal an object proximate to said body portion.

6. A method of forming and using a magnetic image from a body portion of a vehicle as recited in claim 5, wherein said plurality of locations comprise a two-dimensional array of locations.

7. A method of forming and using a magnetic image from a body portion of a vehicle as recited in claim 5, further comprising controlling a safety restraint actuator responsive to the operation of detecting from said image signal an object proximate to said body portion.

8. A method of sensing an occupant in a vehicle, comprising:

a. generating a magnetic field from a source located in a seat base of a seat;

b. sensing a magnetic field at a plurality of locations within a seat back so as to generate an associated plurality of signals whereby each signal is responsive to a magnetic field at one of said plurality of locations;

c. generating an image signal from said plurality of signals; and

d. discriminating a property of an occupant on said seat, wherein said property is selected from a presence of said occupant, a size of said occupant, and a position of said occupant.

9. A method of sensing an occupant in a vehicle as recited in claim 8, wherein said magnetic field is oscillating.

10. A magnetic field sensor, comprising:

a. a plurality of magnetic sensing elements disposed on a first surface, wherein said first surface is located within a body portion of a vehicle, whereby each said magnetic sensing element generates a signal responsive to a magnetic field at said magnetic sensing element, said plurality of magnetic sensing elements thereby generating a corresponding plurality of said signals;

b. a means for generating an image signal from said plurality of said signals; and

c. a means for discriminating from said image signal an object proximate to said body portion.

11. A sensor for sensing a magnetic field as recited in claim 10, wherein each said magnetic sensing element comprises a Hall-effect sensor.

12. A sensor for sensing a magnetic field as recited in claim 10, wherein said means for generating an image signal comprises a scan converter, wherein said scan converter converts said plurality of said signals to a image signal selected from an RS-170 format signal, an RGB format signal, a raster display signal.

13. A sensor for sensing a magnetic field as recited in claim 10, wherein said plurality of magnetic sensing elements are disposed so as to form a two-dimensional array on said first surface.

14. A sensor for sensing a magnetic field as recited in claim 10, further comprising a means for controlling a safety restraint actuator responsive to said means for discriminating from said image signal an object proximate to said body portion.

15. A magnetic field sensor, comprising:

a. a plurality of magnetic sensing elements disposed on a first surface, whereby each said magnetic sensing element generates a signal responsive to a magnetic field at said magnetic sensing element, said plurality of magnetic sensing elements thereby generate a corresponding plurality of said signals;

b. a plurality of magnetic focusing elements disposed on a second surface proximate to said first surface, wherein each magnetic focusing element of said plurality of magnetic focusing elements comprises a material having a magnetic permeability substantially greater than air, said material is selected from a ferromagnetic material, a ferrite material and a mu-metal material, and each one of said plurality of magnetic focusing elements is proximate to one of said plurality of magnetic sensing elements and is shaped so as to concentrate at said one of said plurality of magnetic sensing elements a magnetic flux from the magnetic field; and

c. a means for generating an image signal from said plurality of said signals.

16. A sensor for sensing a magnetic field as recited in claim 15, wherein each said magnetic sensing element comprises a Hall-effect sensor.

17. A sensor for sensing a magnetic field as recited in claim 15, wherein said means for generating an image signal comprises a scan converter, wherein said scan converter converts said plurality of said signals to a image signal selected from an RS-170 format signal, an RGB format signal, a raster display signal.

18. A sensor for sensing a magnetic field as recited in claim 17, further comprising a display operatively connected to said means for generating an image signal for displaying said image signal.

19. A sensor for sensing a magnetic field as recited in claim 15, wherein said plurality of magnetic sensing elements are disposed so as to form a one-dimensional array on said first surface, further comprising a means for translating said one-dimensional array in a direction transverse to said one-dimensional array, and a means for providing a translational position of said one-dimensional array to said means for generating an image signal, wherein said image signal is responsive to said translational position.

20. A sensor for sensing a magnetic field as recited in claim 19, wherein said first surface is located proximate to a body portion of a vehicle.

21. A sensor for sensing a magnetic field as recited in claim 15, wherein said plurality of magnetic sensing elements are disposed so as to form a two-dimensional array on said first surface.

22. A sensor for sensing a magnetic field as recited in claim 21, wherein said first surface is located within a seat back of a seat, further comprising a source of a magnetic field in a seat base of said seat.