Sensor using the capacitive measuring principle
First Claim
1. A sensor using a capacitive measuring principle for detecting an approaching dielectric medium, said sensor being adapted for use in an anti-pinching system, and comprising:
- a capacitor and an evaluation electronic system, wherein a variation of a capacitance of the capacitor caused by the dielectric medium can be measured, and wherein the capacitor can be operated in succession using at least two different frequencies or at least two different pulse duty factors, wherein a group of measurements comprising at least two measurements is performed using a different frequency or different pulse duty factors of the charging voltage for each of said two measurements, and wherein a conclusion about water entering into a field of the capacitor is drawn, if the variation of the capacitance caused by the dielectric medium takes up different values in the case of all the measurements within a group, or a conclusion about a dielectric medium differing from water entering into a field of the capacitor is drawn, if the variation of the capacitance caused by the dielectric medium is substantially constant in the case of all the measurements within a group.
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Accused Products
Abstract
The invention relates to a sensor which uses the capacitive measuring principle which is used to detect the proximity of a dielectric medium, preferably for detecting a human body part, which is used in an anti-pinching system. The sensor includes a capacitor and an evaluation electronic system. The variation of the capacity of the capacitor, which is caused by the medium, can be measured. The capacitor, which can establish a distinction between a human body part or a solid and water and/or humidity, is characterized in that the capacitor can be operated in a successive manner by at least two different frequencies and/or at least two different pulse duty factors by using the different ratio of said elements in a variable electric field. The invention also relates to a corresponding method.
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Citations
19 Claims
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1. A sensor using a capacitive measuring principle for detecting an approaching dielectric medium, said sensor being adapted for use in an anti-pinching system, and comprising:
a capacitor and an evaluation electronic system, wherein a variation of a capacitance of the capacitor caused by the dielectric medium can be measured, and wherein the capacitor can be operated in succession using at least two different frequencies or at least two different pulse duty factors, wherein a group of measurements comprising at least two measurements is performed using a different frequency or different pulse duty factors of the charging voltage for each of said two measurements, and wherein a conclusion about water entering into a field of the capacitor is drawn, if the variation of the capacitance caused by the dielectric medium takes up different values in the case of all the measurements within a group, or a conclusion about a dielectric medium differing from water entering into a field of the capacitor is drawn, if the variation of the capacitance caused by the dielectric medium is substantially constant in the case of all the measurements within a group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for detecting an approaching dielectric medium, said method being adapted for use in an anti-pinching system, and comprising:
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providing a capacitor and an evaluation electronic system; and measuring with a sensor a variation of a capacitance of the capacitor caused by the dielectric medium, wherein the capacitor is operated in succession using at least two different frequencies or at least two different pulse duty factors, wherein a group of measurements comprising at least two measurements is performed using a different frequency or different pulse duty factors of the charging voltage for each of said two measurements, and wherein a conclusion about water entering into a field of the capacitor is drawn, if the variation of the capacitance caused by the dielectric medium takes up different values in the case of all the measurements within a group, or a conclusion about a dielectric medium differing from water entering into a field of the capacitor is drawn, if the variation of the capacitance caused by the dielectric medium is substantially constant in the case of all the measurements within a group. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification