Capacitive sensor device and method for calibrating a capacitive sensor device
First Claim
1. A capacitive sensor device for approach and/or contact detection, comprising at least one generator electrode, at least one measurement electrode and at least one calibration electrode, wherein the at least one calibration electrode is arranged in a predefined distance adjacent to the at least one measurement electrode, wherein the at least one measurement electrode and the at least one calibration electrode are assigned to the at least one generator electrode, wherein the at least one generator electrode receives an alternating generator voltage and the at least one calibration electrode receives an alternating calibrating voltage, and wherein the at least one calibration electrode may be operated at least in a first operating mode and a second operating mode, whereinin each of the operating modes the calibrating voltage is equal to or smaller than the generator voltage, andthe calibrating voltage is different in each operating mode;
- and further comprising an evaluation device which is configured to measure a capacitance between the measurement electrode (M) and ground while the calibration electrode is operated in the first and second operating mode, respectively and to determine a difference between the measurements, wherein the evaluation device furthermore compares the difference between the measurements with a threshold value to determine whether a calibration can be performed.
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Accused Products
Abstract
A capacitive sensor device for approach and/or contact detection has at least one generator electrode, at least one measurement electrode and at least one calibration electrode, wherein the at least one calibration electrode is arranged in a predefined distance adjacent to the at least one measurement electrode, wherein the at least one measurement electrode and the at least one calibration electrode are assigned to the generator electrode, wherein the at least one generator electrode may be loaded with a generator voltage and the at least one calibration electrode may be loaded with a calibrating voltage, and wherein the at least one calibration electrode at least may be operated in a first operating mode and a second operating mode, wherein in each of the operating modes the calibrating voltage lies between a ground voltage and the generator voltage, and the calibrating voltage is different in each operating mode.
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Citations
20 Claims
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1. A capacitive sensor device for approach and/or contact detection, comprising at least one generator electrode, at least one measurement electrode and at least one calibration electrode, wherein the at least one calibration electrode is arranged in a predefined distance adjacent to the at least one measurement electrode, wherein the at least one measurement electrode and the at least one calibration electrode are assigned to the at least one generator electrode, wherein the at least one generator electrode receives an alternating generator voltage and the at least one calibration electrode receives an alternating calibrating voltage, and wherein the at least one calibration electrode may be operated at least in a first operating mode and a second operating mode, wherein
in each of the operating modes the calibrating voltage is equal to or smaller than the generator voltage, and the calibrating voltage is different in each operating mode; and further comprising an evaluation device which is configured to measure a capacitance between the measurement electrode (M) and ground while the calibration electrode is operated in the first and second operating mode, respectively and to determine a difference between the measurements, wherein the evaluation device furthermore compares the difference between the measurements with a threshold value to determine whether a calibration can be performed. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for determining whether an instant is suitable for calibrating a capacitive sensor device, wherein the sensor device comprises at least one generator electrode, at least one measurement electrode and at least one calibration electrode, wherein the at least one measurement electrode and the at least one calibration electrode are arranged in a predefined distance adjacent to each other and are assigned to the at least one generator electrode, the method comprising:
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feeding an alternating generator voltage to the at least one generator electrode, for a first measurement, feeding a first alternating calibration voltage to the calibration electrode and measuring a capacitance between the first measurement electrode (M) and ground as a first sensor signal, for a second measurement, feeding a second alternating calibration voltage to the calibration electrode and measuring a capacitance between the first measurement electrode (M) and ground as a second sensor signal, wherein the first calibrating voltage is chosen to be different from the second calibrating voltage and both calibrating voltages are chosen such that they are equal to or less than the generator voltage; determining a difference between the first sensor signal and the second sensor signal, and carrying out the calibration of the capacitive sensor device, when the difference in its absolute value is greater than a predefined threshold value. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A handheld device, comprising a capacitive sensor device for approach and/or contact detection, comprising at least one generator electrode, at least one measurement electrode and at least one calibration electrode, wherein the at least one calibration electrode is arranged in a predefined distance adjacent to the at least one measurement electrode, wherein the at least one measurement electrode and the at least one calibration electrode are assigned to the at least one generator electrode, wherein the at least one generator electrode receives an alternating generator voltage and the at least one calibration electrode receives an alternating calibrating voltage, and wherein the at least one calibration electrode is operated at least in a first operating mode and a second operating mode, wherein
in each of the operating modes the calibrating voltage is equal to or smaller than the generator voltage, and the calibrating voltage is different in each operating mode; and further comprising an evaluation device which is configured to measure a capacitance between the measurement electrode (M) and ground while the calibration electrode is operated in the first or second operating mode, respectively and to determine a difference between the measurements, wherein the evaluation device furthermore compares the difference between the measurements with a threshold value to determine whether a calibration can be performed. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method for operating a handheld device, comprising a capacitive sensor device for approach and/or contact detection, comprising at least one generator electrode, at least one measurement electrode and at least one calibration electrode, wherein the at least one calibration electrode is arranged in a predefined distance adjacent to the at least one measurement electrode, wherein the at least one measurement electrode and the at least one calibration electrode are assigned to the generator electrode, wherein the at least one generator electrode is loaded with a generator voltage and the at least one calibration electrode is loaded with a calibrating voltage, and wherein the at least one calibration electrode is operated at least in a first operating mode and a second operating mode, wherein in each of the operating modes the calibrating voltage lies between a ground voltage and the generator voltage, and the calibrating voltage is different in each operating mode, the method comprising:
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loading the at least one generator electrode with an alternating generator voltage, for a first measurement, loading the calibration electrode with a first alternating calibration voltage and measuring a capacitance between the first measurement electrode (M) and ground as a first sensor signal, for a second measurement, loading the calibration electrode with a second alternating calibration voltage and measuring a capacitance between the first measurement electrode (M) and ground as a second sensor signal, wherein the first calibrating voltage is chosen to be different from the second calibrating voltage and both calibrating voltages are chosen such that they are equal to or less than the generator voltage; determining a difference between the first sensor signal and the second sensor signal, and carrying out the calibration of the capacitive sensor device, when the difference in its absolute value is greater than a predefined threshold value. - View Dependent Claims (20)
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Specification