SENSOR ARRANGEMENT AND METHOD FOR OPERATION OF A SENSOR ARRANGEMENT

• US 20130278277A1
• Filed: 10/25/2011
• Published: 10/24/2013
• Est. Priority Date: 10/28/2010
• Status: Active Grant

• Current Assignee: ams AG (Ams-Osram AG)
• Original Assignee: ams AG (Ams-Osram AG)
• Inventors: Trattler, Peter
• Granted Patent: US 9,442,142 B2
• Time in Patent Office: Days
• US Class Current: 324/679
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/960725 Charge-transfer
• CPC Class Codes: H03K 2217/960775 Emitter-receiver or "fringe" type detection, i.e. one or more field emitting electrodes and corresponding one or more receiving electrodes

Abstract

A sensor arrangement, in particular for a non-contacting measurement, comprises a signal generator (SRC) which is connected to a first electrode (EL1). A first detector (Det1) is connected to the first electrode (EL1), and is designed for a capacitive measurement by means of the first electrode (EL1). A second detector (Det2) is connected to a second electrode (EL2) and is designed to use the first and the second electrodes (EL1, EL2) to carry out a capacitive measurement. A method for operation of the sensor arrangement is likewise specified.

Claims

1. A sensor arrangement, in particular for contactless measurement, comprising:

a signal generator, which is connected to a first electrodes;

a first detector, which is connected to the first electrode and which is designed for a capacitive measurement by means of the first electrode; and

a second detector, which is connected to a second electrode and is designed to perform a capacitive measurement by means of the first and second electrodes.

2. The sensor arrangement according to claim 1, wherein the first detector is designed to measure a first signal at the first electrode,

wherein the first signal is indicative of a capacitive coupling of an object to the first electrode, and

wherein the second detector is designed to measure a second signal at the second electrode, wherein the second signal is indicative of a capacitive coupling of an object to the first and second electrodes.

3. The sensor arrangement according to claim 1 or 2, wherein the first detector is designed to measure, by means of a reference signal, whether the signal generator is connected to a ground potential.

4. The sensor arrangement according to claim 1, wherein the first and second detectors each comprise at least one detection amplifier,

wherein the first signal and a first reference signal can be supplied at the at least one detection amplifier of the first detector, and which detection amplifier provides a first detection signal depending on the first signal and the first reference signal, and

wherein the second signal and a second reference can be supplied at the at least one detection amplifier of the second detector, and which detection amplifier provides a second detection signal depending on the second signal and the second reference signal.

5. The sensor arrangement according to claim 1, wherein the first electrode is connected to the first detector and the signal generator by means of a first switch,

wherein the signal generator is connected to the second detector by means of a second switch, and

wherein the second detector has a further detection amplifier, to which the second signal and a third reference signal can be supplied, and which detection amplifier provides a third detection signal depending on the second signal and the third reference signal.

6. The sensor arrangement according to claim 1, wherein the first or second detector is/are coupled to a charge measurement apparatus, and

wherein the charge measurement apparatus provides the first or second signal.

7. The sensor arrangement according to claim 6, wherein the charge measurement apparatus has an integrator, at which a first measurement reference is present and which supplies the first or second signal to the first or second detector by means of an output, and

wherein a first measurement switch couples either an input of the integrator or a second measurement reference to the first or second electrode.

8. The sensor arrangement according to claim 6, wherein the charge measurement apparatus comprises:

a flipflop, which is connected on the input side to a first and a second auxiliary amplifier, wherein the first measurement reference is present at the first auxiliary amplifier and the second measurement reference is present at the second auxiliary amplifier, and the flipflop provides an output signal on the output side, which output signal can be supplied to the first or second detector; and

a second measurement switch, which is controllable by means of the output signal in such a way that the second measurement switch connects either a first or second constant current source electrically conductively to inputs of the first and second auxiliary amplifier and couples to the first or second electrode.

9. The sensor arrangement according to claim 8, wherein the charge measurement apparatus comprises:

the flipflop, which is connected on the input side to the first and second auxiliary amplifiers, wherein the first measurement reference is present at the first auxiliary amplifier and the second measurement reference is present at the second auxiliary amplifier, and the flipflop provides an output signal on the output side;

a phase-locked loop, to which the output signal and a control reference can be supplied and which provides a closed-loop control signal, which can be supplied to the first or second detector; and

first and second adjustable current sources whose respective current intensity can be adjusted by means of the closed-loop control signal.

10. The sensor arrangement according to claim 1, wherein the first or second electrode is surrounded by a capacitive shield.

11. The sensor arrangement according to claim 10, wherein the capacitive shield has voltage tracking.

12. The sensor arrangement according to claim 1, wherein at least one further electrode is provided, and

wherein the at least one further electrode has an associated fourth detector for capacitive measurement.

13. A method for operating a sensor arrangement, in particular for contactless measurement, comprising:

providing a signal current;

implementing a first capacitive measurement by means of a first electrode with respect to a ground potential; and

implementing a second capacitive measurement by means of the first electrode and a second electrode.

14. The method according to claim 13, wherein a first signal is measured by means of a first detection path, which first signal is indicative of a capacitive coupling of an object to the first electrode, and

wherein a second signal is measured by means of a second detection path, which second signal is indicative of a capacitive coupling of the object to the first and second electrode.

15. The method according to claim 13 or 14, wherein the results of the first and second capacitive measurement are used for mutual calibration.