Method of capacitive measurement between an object and an electrode plane by partial synchronous demodulation
AssigneeNanotec Solution
InventorsChristian Neel, Christophe Blondin
Life of this patent
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Abstract
A method of capacitive measurement between an object and an electrode plane is provided, in which method use is made of a processing unit so as to:—apply an excitation signal to the resistive electrode plane, and—determine a value of capacitance on the basis of a measurement of a measurement signal originating from the electrode plane. The excitation signal is a nonsinusoidal signal having at least one discontinuity, and to determine the value of capacitance, the measurement signal is attenuated over a time window, this time window being the duration for which the resistivity of the electrode plane is manifested on the measurement signal in response to the at least one discontinuity.
Claims10
A method of capacitive measurement between an object and an electrode plane, in which method a processor unit operates as follows:
- applying an excitation signal to the resistive electrode plane;
- and
- determining a capacitance value based on a measurement from a measurement signal originating from the electrode plane,
- wherein the excitation signal is a non-sinusoidal signal comprising at least one discontinuity, and in order to determine the capacitance value, the measurement signal is attenuated within a time-lapse window, this time-lapse window being the time period during which the resistivity of the electrode plane is reflected on the measurement signal in response to said at least one discontinuity.
An electronic device comprising:
- a display screen associated with a capacitive detection device, this capacitive detection device comprising an electrode plane;
- a processor unit for detecting the position of an object with respect to the display screen by measuring the capacitance between said object and the electrode plane, the processor unit being configured for carrying out at least the following steps:
- applying an excitation signal to the electrode plane;
- this excitation signal being a non sinusoidal signal comprising at least one discontinuity;
- and
- determining a capacitance value based on a measurement from a measurement signal originating from the electrode plane, and attenuating the measurement signal within a time-lapse window, this time-lapse window being the time period during which the resistivity of the electrode plane is reflected on the measurement signal in response to said at least one discontinuity.
Dependencies are inferred from the claim text.