# US 9,753,070 B2 · Evaluation method and evaluation device for a capacitive contact sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,753,070 B2 - Document ID: US9753070B2 - Status: Granted - Kind: B2 - Application number: 14/129,419 - Filed: 2012-06-28 - Published: 2015-01-15 - Granted: 2017-09-05 - Earliest claimed: 2011-07-01 - Assignees: Microchip Technology Incorporated - Applicants: Stefan Burger; Holger Steffens - Inventors: Stefan Burger; Holger Steffens - Web page: https://patentgrep.com/patent/US9753070B2 ## CPC - H03K 17/962: {Capacitive touch switches} - G01D 5/24: by varying capacitance - G01R 27/2605: {Measuring capacitance (capacitive sensors G01D5/24)} - H03K 2217/96054: Double function: touch detection combined with detection of a movable element - H03K 2217/960775: Emitter-receiver or "fringe" type detection, i.e. one or more field emitting electrodes and corresponding one or more receiving electrodes - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract In an evaluation method for a capacitive contact sensor with at least one transmitting and at least one receiving electrode, which are able to be brought into a capacitive coupling, —at the at least one receiving or sensor electrode a measurement signal is tapped, which represents the temporal course of the coupling capacitance between the at least one transmitting electrode and the at least one receiving electrode and the temporal course of the capacitive load of the sensor electrode, respectively, —a reference signal is created from the measurement signal, and —at least one detection signal is created, when the reference signal meets at least one detection criterion. An evaluation device may be coupled with at least one transmitting electrode and at least one receiving electrode or with at least one sensor electrode of the capacitive contact sensor and is adapted to carry out the above evaluation method. ## Claims ### Claim 1 An evaluation method for a capacitive contact sensor, which comprises at least one transmitting electrode and at least one receiving electrode, which are able to be brought into a capacitive coupling, wherein at the at least one receiving electrode a measurement signal is tapped, which represents the temporal course of the coupling capacitance between the at least one transmitting electrode and the at least one receiving electrode, from the measurement signal a reference signal is formed, and at least one detection signal is generated when the reference signal meets at least one detection criterion; wherein the measurement signal is low-pass filtered and wherein following the low-pass filtering of the measurement signal a difference signal between the measurement signal and the low-pass filtered measurement signal is formed, wherein the difference signal constitutes the reference signal. ### Claim 2 (depends on 1) The method of claim 1, wherein the generation of the reference signal comprises one of differentiation of the measurement signal and high-pass filtering of the measurement signal. ### Claim 3 (depends on 1) The method of claim 1, wherein the detection criterion comprises an upper threshold value and/or a lower threshold value. ### Claim 4 (depends on 3) The method of claim 3, wherein the detection criterion comprises an upper limiting value and/or a lower limiting value, wherein the upper limiting value lies above the upper threshold value and the lower limiting value lies below the lower threshold value. ### Claim 5 (depends on 4) The method of claim 4, wherein a first detection signal is created, when the reference signal lies below the lower threshold value and above the lower limiting value. ### Claim 6 (depends on 4) The method of claim 4, wherein a second detection signal is created, when the reference signal lies above the upper threshold value and below the upper limiting value. ### Claim 7 (depends on 3) The method of claim 3, wherein a first detection signal is created, when the reference signal lies below the lower threshold value. ### Claim 8 (depends on 7) The method of claim 7, wherein the first detection signal and a second detection signal are digital signals and wherein an information signal is created, when the detection signals meet at least one information criterion. ### Claim 9 (depends on 8) The method of claim 8, wherein the information criterion comprises at least one of the temporal interval between the rising edges of two pulses of the first detection signal, or between the rising edges of two pulses of the second detection signal, or between the rising edge of a pulse of the first detection signal and of the rising edge of a pulse of the second detection signal exceeds or falls below a predefined value, the pulse duration of a pulse of the first detection signal or of a pulse of the second detection signal exceeds or falls below a predefined value, within a predefined time period the first detection signal or the second detection signal or the first detection signal and the second detection signal comprise a predefined number of pulses, and the sequence of pulses of the first detection signal and of the second detection signal comprises a certain pattern. ### Claim 10 (depends on 3) The method of claim 3, wherein a second detection signal is created, when the reference signal lies above the upper threshold value. ### Claim 11 (depends on 1) The method of claim 1, wherein the coupling capacitance is measured by means of a transmission method or by means of an absorption method. ### Claim 12 (depends on 1) The method of claim 1, wherein the measurement signal is sampled using a predefined first sampling rate, when the signal level of the measurement signal lies below a predefined reference level, and wherein the measurement signal is sampled using a predefined second sampling rate, when the signal level of the measurement signal lies above the predefined reference level. ### Claim 13 (depends on 12) The method of claim 12, wherein the first sampling rate is lower than the second sampling rate. ### Claim 14 (depends on 1) The method of claim 1, wherein the measurement signal is amplified using a predefined first amplification, when the signal level of the measurement signal lies below a predefined reference level, and wherein the measurement signal is amplified using a predefined second amplification, when the signal level of the measurement signal lies above the predefined reference level, wherein the second amplification is chosen such that the measurement signal always is in the operating range of the capacitive contact sensor. ### Claim 15 (depends on 1) The method of claim 1, wherein at the receiving electrode at least one second measurement signal is tapped, wherein prior to creating the reference signal the measurement signal and the at least one second measurement signal are combined with each another, and wherein the reference signal is created from the combined measurement signal. ### Claim 16 (depends on 15) The method of claim 15, wherein the measurement signals are subjected to a signal pre-processing prior to combining. ### Claim 17 (depends on 1) An evaluation device for a capacitive contact sensor, coupled with at least one transmitting electrode and at least one receiving electrode of the capacitive contact sensor and which is adapted to carry out an evaluation method of claim 1. ### Claim 18 (depends on 1) A device, at which at least one transmitting electrode and at least one receiving electrode are arranged, which are coupled with an evaluation device, wherein the evaluation device is adapted to carry out an evaluation method according to claim 1. ### Claim 19 (depends on 18) The device of claim 18, which comprises at least one of a mobile radio unit, a remote control, input means for gaming consoles, portable mini computers, a smart phone, a computer mouse and input means for computer. ### Claim 20 (depends on 18) The device of claim 18, wherein the device is designed in a deformable manner, wherein a deformation of a handheld device causes a variation of the coupling capacitance between the at least one transmitting electrode and the at least one receiving electrode. ### Claim 21 An evaluation method for a capacitive contact sensor, wherein the capacitive contact sensor is configured to evaluate an alternating electric field generated by the capacitive contact sensor, wherein a sensor electrode generates a measurement signal, and wherein from the measurement signal a reference signal is formed, and at least one detection signal is generated, when the reference signal meets at least one detection criterion; wherein the measurement signal is low-pass filtered and wherein following the low-pass filtering of the measurement signal a difference signal between the measurement signal and the low-pass filtered measurement signal is formed, wherein the difference signal constitutes the reference signal. ### Claim 22 (depends on 21) The method of claim 21, wherein the generation of the reference signal comprises one of differentiation of the measurement signal and high-pass filtering of the measurement signal. ### Claim 23 (depends on 21) The method of claim 21, wherein the detection criterion comprises an upper threshold value and/or a lower threshold value. ### Claim 24 (depends on 23) The method of claim 23, wherein the detection criterion comprises an upper limiting value and/or a lower limiting value, wherein the upper limiting value lies above the upper threshold value and the lower limiting value lies below the lower threshold value. ### Claim 25 (depends on 24) The method of claim 24, wherein a first detection signal is created, when the reference signal lies below the lower threshold value and above the lower limiting value. ### Claim 26 (depends on 24) The method of claim 24, wherein a second detection signal is created, when the reference signal lies above the upper threshold value and below the upper limiting value. ### Claim 27 (depends on 23) The method of claim 23, wherein a first detection signal is created, when the reference signal lies below the lower threshold value. ### Claim 28 (depends on 27) The method of claim 27, wherein the first detection signal and a second detection signal are digital signals and wherein an information signal is created, when the detection signals meet at least one information criterion. ### Claim 29 (depends on 28) The method of claim 28, wherein the information criterion comprises at least one of the temporal interval between the rising edges of two pulses of the first detection signal, or between the rising edges of two pulses of the second detection signal, or between the rising edge of a pulse of the first detection signal and of the rising edge of a pulse of the second detection signal exceeds or falls below a predefined value, the pulse duration of a pulse of the first detection signal or of a pulse of the second detection signal exceeds or falls below a predefined value, within a predefined time period the first detection signal or the second detection signal or the first detection signal and the second detection signal comprise a predefined number of pulses, and the sequence of pulses of the first detection signal and of the second detection signal comprises a certain pattern. ### Claim 30 (depends on 23) The method of claim 23, wherein a second detection signal is created, when the reference signal lies above the upper threshold value. ### Claim 31 (depends on 21) The method of claim 21, wherein the measurement signal is sampled using a predefined first sampling rate, when the signal level of the measurement signal lies below a predefined reference level, and wherein the measurement signal is sampled using a predefined second sampling rate, when the signal level of the measurement signal lies above the predefined reference level. ### Claim 32 (depends on 31) The method of claim 31, wherein the first sampling rate is lower than the second sampling rate. ### Claim 33 (depends on 21) The method of claim 21, wherein the measurement signal is amplified using a predefined first amplification, when the signal level of the measurement signal lies below a predefined reference level, and wherein the measurement signal is amplified using a predefined second amplification, when the signal level of the measurement signal lies above the predefined reference level, wherein the second amplification is chosen such that the measurement signal always is in the operating range of the capacitive contact sensor. ### Claim 34 (depends on 21) The method of claim 21, wherein prior to creating the reference signal the measurement signal and at least one second measurement signal are combined with each another, and wherein the reference signal is created from the combined measurement signal. ### Claim 35 (depends on 34) The method of claim 34, wherein the measurement signals are subjected to a signal pre-processing prior to combining.