Position detecting system based on inductive sensing

Patent metadata

Field	Value
Publication number	US-10036656-B2
Application number	US-201615333033-A
Country	US
Kind code	B2
Filing date	Oct 24, 2016
Priority date	Mar 4, 2013
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

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 first sensing plane;
a first differential sensor having a first coil with a first longitudinal axis substantially orthogonal to the first sensing plane, the first coil to generate a first time varying magnetic field with a plurality of first magnetic field vectors that intersect a first sensing domain area of the first sensing plane, each first magnetic field vector that intersects the first sensing domain area having a normal component that lies orthogonal to the first sensing plane and a tangent component that lies parallel to the first sensing 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 first sensing plane;
a second differential sensor having a second coil with a second longitudinal axis substantially orthogonal to the first sensing plane, the second coil to generate a second time varying magnetic field with a plurality of second magnetic field vectors that intersect a second sensing domain area of the first sensing plane, each second magnetic field vector that intersects the first sensing domain area having a normal component that lies orthogonal to the first sensing plane and a tangent component that lies parallel to the first sensing 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 second time varying magnetic field at an intersection of the second longitudinal axis and the first sensing plane;
a first target being movable within the first sensing plane, some portion of the first target always lying within the first sensing domain area of the first sensing plane; and
a second target being movable within the first sensing plane, some portion of the second target always lying within the second sensing domain area of the first sensing plane;
the first and second targets configured to move simultaneously through respectively the first and second sensing domain areas;
processing circuitry coupled to the first and second differential sensors, the processing circuit controlling the first and second differential sensors to determine a differential response of the first and second differential sensor to the first and second targets;
a support structure connected to the first sensor, the second sensor, the first target and the second target.

2. The system of claim 1 , wherein
the first target is configured with a first shape; and
the second target configured with a second shape that is a reverse inverted orientation of the first shape;
the respective responses of the first and second differential sensors to the simultaneous movement of respectively the first and second targets being differentially inverse.

3. The system of claim 2 , wherein the first and second targets are configured as right triangles, and oriented with facing hypotenuses.

4. The system of claim 1 , wherein the first and second targets are configured with respectively coarse and fine shapes to provide respectively coarse and fine responses of the first and second differential sensors to the simultaneous movement of respectively the first and second targets.

5. The system of claim 4 , wherein
the first target is configured with a first shape to provide a coarse response to movement of the first target along the first shape; and
the second target is configured with a concatenation of multiple copies of a second shape to provide a fine response to movement of the second target from one concatenated second shape to a next concatenated second shape.

6. The system of claim 1 , wherein the processing circuitry is one of:
a multiplexer coupled to the first and second differential sensors, and a processor coupled to the multiplexer; or
first and second processors coupled respectively to the first and second differential sensors.

7. The system of claim 1 , wherein at least one of the first and second targets is a negative shape configured as a slot in a sheet of conductive material.

8. A position detecting system comprising:
first and second sensing planes with a substantially parallel orientation;
a differential sensor having a first coil disposed between the first and second sensing planes, the first coil having a first longitudinal axis substantially orthogonal to the first and second sensing planes, the first coil to generate a first time varying magnetic field with a plurality of first magnetic field vectors that intersect a first sensing domain area of the first sensing plane, and a plurality of second magnetic field vectors that intersect a second sensing domain area of the second sensing plane, opposite the first sensing domain area of the first sensing plane, each of the first and second magnetic field vectors having a normal component that lies orthogonal to the respective sensing plane and a tangent component that lies parallel to the respective sensing 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 respective time varying magnetic field at an intersection of the first longitudinal axis and the oppositely disposed first and second sensing planes;
a first target being movable within the first sensing plane, some portion of the first target always lying within the first sensing domain area of the first sensing plane; and
a second target being movable within the second sensing plane, some portion of the second target always lying within the second sensing domain area of the second sensing plane;
the first and second targets configured to move simultaneously through respectively the first and second sensing domain areas;
processing circuitry coupled to the differential sensors, the processing circuit controlling the differential sensor to determine a differential response of the differential sensor to the first and second targets;
a support structure connected to the first sensor, the second sensor, the first target and the second target.

9. The system of claim 8 , wherein the first and second targets are configured with substantially identical shapes to provide the differential response of the differential sensor to the substantially simultaneous movement of the first and second targets within respective first and second sensing domain areas.

10. The system of claim 8 , wherein at least one of the first and second targets is a negative shape configured as a slot in a sheet of conductive material.

11. A position detecting system comprising:
at least one sensing plane;
a differential sensor having at least a first coil with an associated longitudinal axis substantially orthogonal to the at least one sensing plane;
the differential sensor to generate at least one time varying magnetic field that creates at least first and second sensing domain areas of the at least one sensing plane;
each of the first and second sensing domain areas defined by magnetic field vectors having a normal component that lies orthogonal to the respective sensing plane and a tangent component that lies parallel to the respective sensing 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 respective time varying magnetic field at an intersection of the associated longitudinal axis and the at least one sensing plane;
a first target being movable within th

Assignees

• Texas Instruments Inc

Inventors

• Reitsma George Pieter
• Henderson Richard Dean
• Baldwin Jonathan

Classifications

• G01D5/202 Primary

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

• H03H2/005

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