Contactless Sensor

Patent metadata

Field	Value
Publication number	US-2016290833-A1
Application number	US-201514677287-A
Country	US
Kind code	A1
Filing date	Apr 2, 2015
Priority date	Apr 2, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

A sensor includes a source including an electromagnetic structure generating an electromagnetic near-filed upon receiving energy and a detecting unit including at least one coil arranged in proximity to the source such that the electromagnetic near-filed induces, via an inductive coupling, a current passing through the coil. The sensor also includes a measuring unit for measuring a voltage across the coil and a processor for detecting a presence of a target structure in proximity to the source upon detecting a change in a value of the voltage. The target structure is an electromagnetic structure moving at a distance from the source.

First claim

We claim:

1 . A sensor, comprising:
a source including an electromagnetic structure generating an electromagnetic near-filed upon receiving energy; a detecting unit including at least one coil arranged in proximity to the source such that the electromagnetic near-filed induces, via an inductive coupling, a current passing through the coil; a measuring unit for measuring a voltage across the coil; and a processor for detecting a presence of a target structure in proximity to the source upon detecting a change in a value of the voltage, wherein the target structure is an electromagnetic structure moving at a distance from the source.

2 . The sensor of claim 1 , further comprising:
a power source for supplying the energy to the source via a power signal having a resonance frequency, wherein the target structure is a resonant electromagnetic structure with the resonant frequency.

3 . The sensor of claim 1 , wherein the detecting unit includes a pair of connected coils including a first coil and a second coil, wherein the value of the voltage measured by the measurement unit represents a difference between a first voltage across the first coils and a second voltage across the second coil, and wherein the processor determines a relative position of the target structure with respect to the source based on the value of the voltage.

4 . The sensor of claim 3 , wherein the resonant structure moves according to a trajectory in a plane parallel to the electromagnetic structure of the source, further comprising:
a memory storing a mapping between a set of positions of the target structure on the trajectory and a set of values of the voltages, wherein the processor determines the relative position of the target structure using the mapping.

5 . The sensor of claim 1 , wherein the detecting unit includes a pair of connected coils including a first coil and a second coil, wherein the measurement unit measures the voltage across each connected coils including a first voltage measured across the first coils and a second voltage measured across the second coil, and wherein the processor compares the first voltage and the second voltage to determine a relative position of the target structure with respect to the source.

6 . The sensor of claim 4 , wherein the resonant structure moves according to a trajectory in a plane parallel to the electromagnetic structure of the source, further comprising:
a memory storing a mapping between a set of positions of the target structure on the trajectory and a set of corresponding differences between the first and the second voltages, wherein the processor determines the relative position of the target structure using the mapping.

7 . The sensor of claim 1 , wherein the detecting unit includes a pair of connected coils including a first coil and a second coil, wherein the measurement unit measures the voltage across each connected coils including a first voltage measured across the first coils and a second voltage measured across the second coil, and wherein the processor determines a relative position of the target structure with respect to the source based on the first voltage and the second voltage.

8 . The sensor of claim 7 , further comprising:
a memory storing a mapping between a set of different relative positions of the target structure and a set of corresponding pairs of values of the first and the second voltages, wherein the processor determines the relative position of the target structure using the mapping.

9 . The sensor of claim 3 , wherein the connected coils have identical shape and are centered with respect to the electromagnetic structure of the source such that a difference between the first and the second voltages is below a threshold when the target structure is outside the electromagnetic near-field.

10 . The sensor of claim 3 , wherein the processor determines the relative position of the target structure to be aligned with the connected coils if the difference between the first and the second voltages during the presence of the target structure within the electromagnetic near field equals a difference between the first and the second voltages when the target structure is outside the electromagnetic near-field.

11 . The sensor of claim 3 , wherein the processor compares magnitudes of the first and the second voltages with reference voltages to detect a presence of the target structure within the electromagnetic near field.

12 . The sensor of claim 3 , wherein the detecting unit includes a plurality of connected coils, and wherein the processor determines the relative position of the target structure based on a combination of values of voltages determined across each coil of the detecting unit.

13 . The sensor of claim 3 , wherein the detecting unit includes a set of groups of connected coils, and wherein the processor determines the relative position of the target structure based on a combination of values of voltages determined across each coil of the detecting unit.

14 . The sensor of claim 1 , wherein the coil of the detecting unit is an 8-shaped coil.

15 . The sensor of claim 1 , wherein the coil of the detecting unit and the electromagnetic structure of the source are arranged on a printed circuit board.

16 . The sensor of claim 1 , wherein the target structure includes multiple resonant structures.

17 . A sensor, comprising:
a source including an electromagnetic structure; a power source for supplying a power signal with the resonance frequency to the electromagnetic structure to generate a magnetic near-filed around the electromagnetic structure; a detecting unit including connected coils arranged in proximity to the source such that the magnetic near-filed induces a current passing through the connected coils via an inductive coupling, wherein connected coils includes a first coil and a second coil; a measurement unit for measuring voltages across each connected coils including a first voltage measured across the first coils and a second voltage measured across the second coil; and a processor for comparing the first voltage and the second voltage and for determining a relative position of a target structure with respect to the source or with respect to the pair of connected coils based on a difference between the first and the second voltages.

18 . The sensor of claim 17 , wherein the target structure moves according to a trajectory, and wherein the sensor further comprising:
a memory storing a mapping between a set of positions of the target structure on the trajectory and a set of pairs of the first and the second voltages.

19 . The sensor of claim 17 , wherein the processor determines the position of the target structure to be aligned with connected coils if the difference between the first and the second voltages during the presence of the target structure within the magnetic near field is equal to the difference between the first and the second voltages when the target structure outside the magnetic near-field.

20 . The sensor of claim 17 , wherein the processor compares magnitudes of the first and the second voltages with reference voltages to detect a presence of the target structure within the magnetic near field.

Assignees

• Mitsubishi Electric Res Laboratories Inc

Inventors

• Wang Bingnan
• Teo Koon Hoo

Classifications

• G01D5/2225 Primary

  by a movable non-ferromagnetic conductive element · CPC title

• G01D2204/14

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• G01D2204/24

  Identification of individual loads, e.g. by analysing current/voltage waveforms · CPC title

• G01B7/004 Primary

  for measuring coordinates of points · CPC title

• Y02B90/20

  Smart grids as enabling technology in buildings sector (smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00) · CPC title