Position detecting system

Patent metadata

Field	Value
Publication number	US-9479134-B2
Application number	US-201314139701-A
Country	US
Kind code	B2
Filing date	Dec 23, 2013
Priority date	Mar 4, 2013
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

A position detecting system detects and responds to the movement of a target through a sensing domain area of a plane. The movement causes the amount of the target that lies within a sensing domain area to change. A portion of the target always lies within at least one of the sensing domain areas of the plane.

First claim

What is claimed is:

1. A position detecting system comprising:
a sensor having a coil, the coil having a longitudinal axis, the coil to generate a time varying magnetic field, the time varying magnetic field having a plurality of magnetic field vectors that intersect a sensing domain area of a plane, the plane being substantially orthogonal to the longitudinal axis, each magnetic field vector that intersects the sensing domain area having a normal component that lies orthogonal to the plane and a tangent component that lies parallel to the plane, a magnitude of the normal component being substantially greater than a magnitude of the tangent component, an orientation of the normal component matching an orientation of the time varying magnetic field at an intersection of the longitudinal axis and the plane;
a target being movable within the plane, a portion of the target always lying within the sensing domain area of the plane; and
a support structure connected to the sensor and the target.

2. The position detecting system of claim 1 wherein the coil has a coil characteristic that changes as the target moves within the sensing domain area of the plane.

3. The position detecting system of claim 2 wherein:
the target receives an amount of magnetic flux from the time varying magnetic field;
the amount of magnetic flux received by the target changes as the target moves within the plane; and
the coil characteristic changes in response to changes in the amount of magnetic flux received by the target.

4. The position detecting system of claim 2 wherein the coil characteristic that changes in response to changes in the amount of magnetic flux received by the target is an inductance of the coil.

5. The position detecting system of claim 2 wherein the coil characteristic that changes in response to changes in the amount of magnetic flux received by the target is a quality factor of the coil.

6. The position detecting system of claim 2 and further comprising a processing circuit that determines a position of the target with respect to a position of the sensor in response to the coil characteristic.

7. The position detecting system of claim 6 wherein the processing circuit and the sensor are not co-located.

8. A position detecting system comprising:
a first sensor having a first coil, the first coil having a first longitudinal axis, the first coil to generate a first time varying magnetic field, the first time varying magnetic field having a plurality of first magnetic field vectors that intersect a first sensing domain area of a plane, each first magnetic field vector that intersects the first sensing domain area having a normal component that lies orthogonal to the plane and a tangent component that lies parallel to the plane, a magnitude of the normal component being substantially greater than a magnitude of the tangent component, an orientation of the normal component matching an orientation of the first time varying magnetic field at an intersection of the first longitudinal axis and the plane;
a second sensor having a second coil, the second coil having a second longitudinal axis, the second coil to generate a second time varying magnetic field, the second time varying magnetic field having a plurality of second magnetic field vectors that intersect a second sensing domain area of the plane, the plane being substantially orthogonal to the first and second longitudinal axes;
a target being movable within the plane, some portion of the target always lying within at least one of the first and second sensing domain areas of the plane; and
a support structure connected to the first sensor, the second sensor, and the target.

9. The position detecting system of claim 8 wherein:
the first coil has a first coil characteristic that changes as the target moves within the first sensing domain area of the plane; and
the second coil has a second coil characteristic that changes as the target moves within the second sensing domain area of the plane.

10. The position detecting system of claim 9 and further comprising an integrated circuit having:
a multiplexor that is connected to an output of the first sensor and an output of the second sensor; and
a processing circuit that is connected to the multiplexor, the processing circuit controlling the multiplexor to determine whether a response from the first sensor or a response from the second sensor is to be passed to the processing circuit, the processing circuit determining a position of the target with respect to a position of the first and second sensors in response to the first and second coil characteristics.

11. The position detecting system of claim 10 wherein the integrated circuit and the first and second sensors are not co-located.

12. The position detecting system of claim 9 and further comprising an integrated circuit having:
a first processing circuit that is connected to the first sensor, the first processing circuit determining a position of the target with respect to a position of the first sensor in response to the first coil characteristic; and
a second processing circuit that is connected to the second sensor, the second processing circuit determining a position of the target with respect to a position of the second sensor in response to the second coil characteristic.

13. The position detecting system of claim 12 wherein the integrated circuit and the first and second sensors are not co-located.

14. The position detecting system of claim 9 wherein some portion of the target always lies within the first sensing domain area of the plane, and some portion of the target always lying within the second sensing domain area of the plane.

15. A position detecting system comprising:
a first sensor having a first coil, the first coil having a first longitudinal axis, the first coil to generate a first time varying magnetic field, the first time varying magnetic field having a plurality of first magnetic field vectors that intersect a first sensing domain area of a plane, each first magnetic field vector that intersects the first sensing domain area having a normal component that lies orthogonal to the plane and a tangent component that lies parallel to the plane, a magnitude of the normal component being substantially greater than a magnitude of the tangent component, an orientation of the normal component matching an orientation of the first time varying magnetic field at an intersection of the first longitudinal axis and the plane;
a second sensor having a second coil, the second coil having a second longitudinal axis, the second coil to generate a second time varying magnetic field, the second time varying magnetic field having a plurality of second magnetic field vectors that intersect a second sensing domain area of the plane, the plane being substantially orthogonal to the first and second longitudinal axes;
a first target being movable within the plane;
a second target being movable within the plane, some portion of the first target always lying within the first sensing domain area, or some portion of the second target always lying within the second sensing domain area; and
a support structure connected to the first sensor, the first target, the second sensor, and the second target.

16. The position detecting system of claim 15 wherein:
the first coil has a first coil characteristic that changes as the first target moves within the first sensing domain area of the plane; and
the second coil has a second coil characteristic that changes as the second target moves within the second sensing domain area of the plane.

Assignees

• Texas Instruments Inc

Inventors

• Reitsma George Pieter
• Henderson Richard Dean
• Baldwin Jonathan

Classifications

• H03H2/005 Primary

  Coupling circuits between transmission lines or antennas and transmitters, receivers or amplifiers · CPC title

• G01D5/202 Primary

  by movable a non-ferromagnetic conductive element (G01D5/2033 takes precedence) · CPC title