Capacitive sensor device and method for operating a capacitive sensor device

Abstract

Capacitive sensor device (100, 200, 300, 400) for an operating device of a vehicle for detecting an approach and / or contact, comprising: - a first electrically conductive sensor electrode (E1) for capacitively detecting the presence of an input means in a detection area of ​​the sensor device (100, 200, 300, 400), wherein the sensor electrode (E1) has a sensor capacitance (C ex-1 ) trains, - a control and evaluation device (8) with a first connection contact (9, 9A), - a first connecting line (11, 11A), - a first reference capacity (C Ref-1 ), - a first electrical resistance (R1, R1A), and - one with a defined reference potential (V Ref1 , V Ref2) loadable first reference connection contact (15A), wherein the first sensor electrode (E1) is connected via the first connection line (11, 11A) and via the first electrical resistor (R1, R1A) to the first connection contact (9, 9A) of the control and evaluation device (8), and where the first reference capacity (C Ref-1 ) is connected to the first connecting line (11, 11A) between the first connection contact (9, 9A) and the first electrical resistor (R1, R1A) and is connected to a base potential (V Basis ) is connected, characterized in that the sensor device (100, 200, 300, 400) further comprises at least one first Schottky diode (D1), via which the first sensor electrode (E1) is further connected to the first reference terminal contact (15A), wherein the first reference connection contact (15A) is optionally connected to a first defined reference potential (V Ref1) or a second defined reference potential (V Ref2 ) can be loaded, where the first reference potential (V Ref1 ) is greater than the threshold voltage of the first Schottky diode (D1) and the first sensor electrode (E1) is connected to the first reference terminal (15A) via the first Schottky diode (D1) in such a way that the first Schottky diode (D1) is blocked when the first reference potential (V Ref1 ) is applied to the first reference terminal (15A), and where the second reference potential (V Ref2 ) is smaller than the threshold voltage of the first Schottky diode (D1) and the first sensor electrode (E1) is connected to the first reference terminal (15A) via the first Schottky diode (D1) in such a way that the first Schottky diode (D1) opens when the second reference potential (V Ref2 ) is applied to the first reference connection contact (15A).

Description

[0001] The invention relates to a capacitive sensor device for an operating device of a vehicle for detecting an approach and / or contact, wherein the sensor device has at least one first electrically conductive sensor electrode for capacitively detecting the presence of an input means in a detection area of ​​the sensor device, which forms a sensor capacitance with the environment that changes when an input means is present in the detection area of ​​the sensor device, as well as a control and evaluation device with a first connection contact, at least one first connection line, at least one first reference capacitance, at least one first electrical resistance, and a first reference connection contact that can be supplied with a defined reference potential.The first sensor electrode is connected or connectable to the first connection contact of the control and evaluation device via the first connection line and the first electrical resistor. The first reference capacitance is connected or connectable to the first connection line between the first connection contact and the first electrical resistor, and is also connected to a base potential.

[0002] Furthermore, the present invention relates to a method for operating such a capacitive sensor device.

[0003] Generic capacitive sensor devices and corresponding methods for operating such sensor devices are generally known from the prior art, for example from DE 299 24 441 U1, US 9,823,798 B2 or DE 10 2019 128 656 A1, which was not yet published at the time of filing, whereby a wide variety of designs are known which differ primarily in their structure or in relation to the method for controlling the individual components.

[0004] US 2019 / 102040 A1 discloses a touch circuit comprising a detection circuit and an emulation circuit. The detection circuit detects a detection signal. The emulation circuit contains a reference load and receives a signal. The emulation circuit generates an emulation signal according to the reference load and the signal. The touch circuit outputs a touch signal according to the detection signal and the emulation signal.

[0005] US 2017 / 0293375 A1 discloses a capacitive sensor system comprising a measuring electrode, a first switch which can couple the measuring electrode to a first supply voltage during a first mode and to an analog-to-digital converter during a second mode, a second switch which can couple a reference capacitor to a second supply voltage during the first mode and to an open circuit during the second mode, and a resistance element which is connected, on the one hand, between the measuring electrode and the first switch, and, on the other hand, between the reference capacitor and the second switch. DE 10 2007 059 702 A1 discloses a capacitive sensor with at least one reference impedance and at least one measuring capacitor, with at least one electrical alternating signal source, with a current-carrying network, and with an evaluation unit. The reference impedance and the measuring capacitor are connected to the alternating signal source and the evaluation unit via the current-carrying network in such a way that the charging and discharging currents of the reference impedance and the measuring capacitor can be evaluated—at least partially—by the evaluation unit. The capacitive sensor according to the invention avoids—at least partially—disadvantages of the capacitive sensors known from the prior art by virtue of the fact that the reference impedance is tunable.

[0006] Against this background, it is an object of the invention to provide an alternative capacitive sensor device, in particular an improved capacitive sensor device, preferably a capacitive sensor device that has lower parasitic capacitances and / or lower leakage currents. Furthermore, an object of the invention is to provide a method for operating such a sensor device.

[0007] This object is achieved according to the invention by a capacitive sensor device and by a method for operating such a sensor device having the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0008] A capacitive sensor device designed and particularly configured according to the present invention for an operating device of a vehicle for detecting an approach and / or contact has a first electrically conductive sensor electrode for capacitively detecting the presence of an input means in a detection area of ​​the sensor device and a control and evaluation device with a first connection contact, a first connection line, in particular a measuring line, a first reference capacitance, a first electrical resistance, in particular a first ohmic resistance, and a first reference connection contact that can be supplied with a defined reference potential.The sensor electrode forms a sensor capacitance with the environment that changes in the presence of an input means in the detection range of the sensor device and is connected or connectable, in particular electrically, i.e., in particular galvanically, to the first connection contact of the control and evaluation device via the first connection line and the first electrical resistor. The first reference capacitance is connected or connectable, on the one hand, between the first connection contact and the first electrical resistor, to the first connection line, preferably via a first connection node, in particular electrically, and on the other hand, to a base potential, preferably a zero potential, in particular a ground potential.

[0009] A capacitive sensor device according to the present invention is characterized in that the sensor device further comprises a first Schottky diode, via which the first sensor electrode is further connected or connectable to the first reference terminal contact, wherein the first reference terminal contact can be selectively supplied with a first defined reference potential or a second defined reference potential, wherein the first reference potential is greater than the threshold voltage of the first Schottky diode and the first sensor electrode is connected or connectable to the first reference terminal contact via the first Schottky diode in such a way that the first Schottky diode is blocked when the first reference potential is applied to the first reference terminal contact,and wherein the second reference potential is smaller than the threshold voltage of the first Schottky diode and the first sensor electrode is connected or connectable to the first reference terminal contact via the first Schottky diode such that the first Schottky diode opens when the second reference potential is applied to the first reference terminal contact.

[0010] A sensor device according to the invention, in which the connection of the sensor electrode to the reference connection contact is realized via a Schottky diode, has the advantage, in particular compared to a connection of the sensor electrode to the reference connection contact via a transistor switching device or a transistor switching element, as proposed, for example, in DE 10 2019 128 656, that the Schottky diode has a lower parasitic capacitance than a transistor switching device, for example a MOSFET or a bipolar transistor, and there is a lower leakage current than with a transistor switching device, for example a MOSFET or a bipolar transistor, whereby a higher sensor accuracy can be achieved, since the lower parasitic capacitance and the lower leakage current lead to less undesired influence, in particular falsification, of the sensor capacitance.This advantage becomes even greater the more correspondingly interconnected sensor electrodes a corresponding sensor device has. Furthermore, a sensor device according to the invention can provide a capacitive sensor device that requires only one sensor electrode, but which nevertheless fundamentally enables a continuity test, which will be explained in more detail below.

[0011] An “input means” in the sense of the present invention is an input means that causes a change in a capacitive coupling of an environment with the sensor electrode when it enters the detection area of ​​the sensor device, such as a capacitive stylus or a human hand or parts thereof, such as a finger of a human hand or the like.

[0012] In the context of the present invention, the term “detection area” is understood to mean an area, in particular a spatial area, within which an approach and / or contact can be detected, i.e. recognized.

[0013] For the purposes of the present invention, a "control and evaluation device" is understood to mean a combined control and evaluation device which, on the one hand, is configured to control the sensor device, in particular individual components of the sensor device, in particular corresponding circuit devices, arrangements and / or the like, such that a corresponding method for operating the sensor device can be carried out, in particular steps a) to e) of a method according to the invention, and which, on the other hand, is configured to evaluate the detected voltage according to step f). Preferably, the control and evaluation device is a microcontroller or part of a microcontroller. More than one control and evaluation device can also be provided.

[0014] A "connection contact" within the meaning of the present invention can be, for example, a connection pin of a corresponding plug contact or a connection contact of a printed circuit board. However, a connection contact does not have to be a pin or the like, but can fundamentally be any electrical contact, for example, any electrical connection contact on a printed circuit board, such as a solder contact or the like. This means that a connection contact does not necessarily have to represent an input or output.

[0015] A "sensor electrode" of a sensor device according to the invention is in particular an electrically conductive element or an electrically conductive structure for capacitively detecting an approach and / or contact of an input means, for example to a user interface and / or for detecting a contact of a user interface of an operating device with the input means, wherein the sensor electrode can preferably form a sensor surface, in particular the user interface of the operating device, or can be arranged below a user interface in an associated operating device, optionally with a dielectric in between.

[0016] The term “reference potential” in the sense of the invention is understood to mean a defined electrical potential which is used in particular to establish a defined (reference) state of the sensor device during operation of a sensor device according to the invention and / or in preparation for operation.

[0017] In an advantageous embodiment of a sensor device according to the invention, the first electrical resistor is connected or connectable in series between a connection node, via which the reference capacitance is connected to the first connecting line, and the sensor electrode. This allows for a particularly simple and advantageous arrangement of the individual components of the sensor device.

[0018] In a particularly advantageous embodiment of a sensor device designed according to the present invention, the sensor device is designed and configured to be operated based on the so-called “capacitive voltage divider method” (CVD method), which is basically known from the prior art, for example from the aforementioned US 9,823,798 B2, and in particular from the company “Microchip”, as well as from DE 10 2019 129 802, which was not yet published at the time of this application and to which reference is hereby expressly made for further details.

[0019] The first reference capacitance serves in particular to provide a defined charging potential for charge equalization, whereby a particularly advantageous, in particular accurate, sensor device can be provided, wherein the first reference capacitance can be charged in particular with a defined charging potential, in particular via the associated first connecting line.

[0020] For the purposes of the invention, the term "charging potential" refers to a defined electrical potential, which can be selected as needed, for example, and can be set to +5V or -5V. In a particularly simple embodiment, the charging potential can be the potential of a supply voltage of the control and evaluation device, for example, the potential of the positive supply voltage VDD or VCC, as it is sometimes also called, which in a vehicle is preferably between +10V and +14V, in particular approximately +12V.

[0021] The first electrical resistance enables, in particular, a decoupling of the first reference capacitance from the first sensor electrode in the charging cycle and thus the defined charging of the reference capacitance, in particular quickly and precisely, whereby a particularly good detection accuracy of the sensor device can be achieved, in particular a high resolution or short sampling cycles.

[0022] In a preferred embodiment of a sensor device according to the present invention, the sensor device is in particular further designed and configured such that the first reference connection contact can be subjected to a first reference potential which is preferably greater than +3V, +5V or +10V or even further above, in particular if the first Schottky diode is selected such that its parasitic capacitance decreases with increasing level of the applied reference potential, which is particularly preferably the case.

[0023] Preferably, the first Schottky diode is selected such that its parasitic capacitance decreases hyperbolically with increasing reference potential, for example as in Fig. 4 shown.

[0024] In a preferred embodiment of a sensor device according to the present invention, the sensor device is particularly designed and configured such that the second reference potential, to which the first reference connection contact can be applied, is a zero potential (0V), in particular a ground potential (GND). Such a potential is, on the one hand, always below the threshold voltage of a Schottky diode and, on the other hand, can be provided particularly easily, especially in a vehicle. This enables a particularly easy-to-implement method for operating a sensor device according to the invention, in particular a particularly advantageous implementation of an operation of the sensor device, in particular according to a method according to the invention.

[0025] In a further advantageous embodiment of a sensor device according to the present invention, the sensor device further comprises an electronic switching device which is designed and configured to be switched between a first switching state and a second switching state, wherein, when the electronic switching device is in the first switching state, the first reference potential is applied to the first reference connection contact, so that the first Schottky diode is blocked, ie has a high-resistance effect, and when the electronic switching device is in the second switching state, the second reference potential is applied to the first reference connection contact, so that the first Schottky diode opens, ie has a low-resistance effect.By means of such an electronic switching device, it is possible in a particularly simple manner to selectively apply the first reference connection contact, especially in a targeted manner, to the first reference potential or the second reference potential.

[0026] In a further advantageous embodiment of a sensor device according to the present invention, in particular in a further development, the electronic switching device has a control switching device which can be switched from a first switching state to a second switching state, wherein switching of the control switching device to the first switching state causes the first reference potential to be established at the first reference connection contact, and switching of the control switching device to the second switching state causes the second reference potential to be established at the first reference connection contact. The control switching device can be an assembly comprising several switching elements or just a single switching element, for example a transistor switching element or the like, such as a MOSFET (metal oxide semiconductor field-effect transistor) or a bipolar transistor.

[0027] In a further advantageous embodiment of a sensor device according to the present invention, the sensor device further comprises a first terminal to which the first reference potential is applied, and a second terminal to which the second reference potential is applied, wherein the first reference terminal contact is connected or connectable to the first terminal and to the second terminal, in particular via a reference line. This allows a particularly advantageous embodiment or configuration of a sensor device according to the invention to be achieved, in particular a particularly advantageous spatial arrangement of the individual components and a particularly simple arrangement.

[0028] Particularly preferably, the first reference terminal contact is connected or connectable to the first terminal and the second terminal via the reference line in such a way that it is located between the first terminal and the second terminal, so that the first Schottky diode is connected or connectable to the reference line between the first terminal and the second terminal via the reference terminal node. This allows a particularly advantageous spatial arrangement of the individual components of the sensor device to be achieved.

[0029] Preferably, the first terminal is directly connected or connectable to the first reference potential, in particular electrically, preferably to a first pole of a reference voltage source, and the second terminal is connected to the second reference potential, in particular to a second pole of the reference voltage source. This allows the first reference potential and the second reference potential to be provided in a simple manner. In this way, the reference line makes it particularly easy to apply the corresponding reference potential to the first reference terminal contact, in particular in conjunction with an electronic switching device.

[0030] In a further advantageous embodiment of a sensor device according to the present invention, the sensor device, in particular the electronic switching device, has at least one further electrical resistor, preferably an ohmic resistor, in particular a pull-up resistor, wherein the first reference connection contact is connected or connectable to the first connection via this further electrical resistor, preferably electrically, ie galvanically, in particular by means of the reference line.A further electrical resistor connected in this way, in conjunction with a correspondingly designed and connected control switching device, enables the provision of a particularly simply constructed electronic switching device which is designed and configured to be switched between a first switching state and a second switching state in such a way that, when the electronic switching device is in the first switching state, the first reference potential is applied to the first reference connection contact, so that the first Schottky diode is blocked, and when the electronic switching device is in the second switching state, the second reference potential is applied to the first reference connection contact, so that the first Schottky diode opens.

[0031] In a further advantageous embodiment of a sensor device according to the present invention, the first reference connection contact is furthermore connected or connectable to the second connection via the control switching device, in particular by means of the reference line, preferably via another line section of the reference line, in particular such that the further electrical resistor and the control switching device are connected in series between the first connection and the second connection, in particular along the reference line, wherein the first reference connection contact is preferably located between the further electrical resistor and the control switching device. This makes it possible to provide a particularly simply constructed electronic switching device and thus a particularly advantageous sensor device.

[0032] In another possible, particularly preferred embodiment of a sensor device according to the invention, the additional electrical resistor, particularly if it is a pull-up resistor, and / or the electronic control switching device, particularly also, can be part of the electronic switching device. This enables a particularly simple modular design.

[0033] Alternatively, the further resistor may also be a pull-down resistor, whereby this requires a correspondingly different arrangement of the further electrical resistor and of the control switching device relative to the first and second terminals, in particular an arrangement as is fundamentally known from the prior art in order to apply a first or second reference potential to an electrical line or a connection contact selectively and depending on the switching state of the control switching device.

[0034] The electronic switching device or parts or components thereof, for example the control switching device and / or the further electrical resistor, can in principle be arranged outside of the control and evaluation device, or alternatively also be integrated into the control and evaluation device, in which case the design and arrangement of the associated connection contacts and any necessary connection cables are preferably adapted accordingly.If the electronic control device is integrated, for example, into the control and evaluation device, the control and evaluation device preferably has corresponding connection contacts for connecting the electronic control device to a corresponding voltage source and / or a correspondingly suitable voltage source integrated into the control and evaluation device, to which the electronic control device is connected or connectable.

[0035] In a further advantageous embodiment of a sensor device according to the present invention, in particular in a further development, the sensor device further comprises a second connecting line, in particular a control line, and the control and evaluation device further comprises a second connecting contact, wherein the control switching device is preferably connected or connectable via the second connecting line to the second connecting contact of the control and evaluation device.Particularly preferably, the control and evaluation device is further designed and configured to switch the control switching device, in particular via the second connecting line, at least between a first switching state and a second switching state, in particular with the aid of a control signal that can be output by the control and evaluation device via the second connecting contact and transmitted via the second connecting line, which control signal can also be generated by the control and evaluation device. The control and evaluation device is particularly preferably designed and configured to output a control signal to the control switching device via the second connecting contact and the second connecting line.This allows for particularly simple control of the sensor device, in particular particularly simple synchronization with the detection or measurement of the sensor capacitance. In particular, no additional control device is required. Alternatively or additionally, the control switching device can also be controlled by another control device, in particular one designed separately from the control and evaluation device of the sensor device.

[0036] In a particularly advantageous embodiment of a sensor device according to the present invention, the first connection contact and / or the second connection contact can each be switchable as an input and / or as an output and in particular can each be designed as a so-called GPIO contact, ie in particular as a so-called “General Purpose Input Output” contact, which can optionally be assigned different functions or outputs depending on the switching state.Signals can be assigned, wherein the sensor device, in particular the control and evaluation device of the sensor device, preferably has at least one input and / or output port, in particular a switchable input and / or output port, to which the first connection contact and / or the second connection contact is assigned, wherein at least one input and / or output port is preferably designed and configured to output a, in particular defined, voltage, to detect a voltage, to set a respective associated connection contact to a, in particular defined, potential and / or to switch the respective connection contact to high resistance or low resistance.

[0037] The first connection contact and the second connection contact can be assigned to a common input and / or output port, i.e. a common channel or different input and output ports.

[0038] Both connection contacts can preferably be switched as outputs, in particular by switching them to a low impedance, ie to “LOW”, and more preferably alternatively optionally as inputs by switching them to a high impedance, ie to “HIGH”.

[0039] A charging potential, in particular a defined charging potential, can preferably be applied to at least one connection contact, in particular to at least one connection pin of an input and / or output port, in particular at least to the first connection contact, for example a charging potential of +5V, in particular a supply voltage, preferably the positive supply voltage of the control and evaluation device, and a control potential can be applied to another connection contact, preferably to the second connection contact, in particular to at least one other connection pin of the port.

[0040] In a further advantageous embodiment of a sensor device according to the invention, in particular in a further development, the sensor device has at least one analog-to-digital converter, preferably for detecting at least one voltage applied to at least one connection contact, in particular at the first connection contact, wherein the at least one analog-to-digital converter can be coupled, in particular electrically connected, to at least one input and / or output port, wherein preferably at least one analog-to-digital converter can be electrically connected, in particular switchably contacted, to the associated connection contact via an input and / or output port, so that in particular at least one input of an analog-to-digital converter can be connected to at least one connection contact. A sensor device according to the invention can also have a plurality of analog-to-digital converters.

[0041] In a further advantageous embodiment of a sensor device according to the present invention, the control switching device can, as already mentioned above, comprise or be a field-effect transistor. This makes it possible to provide a particularly simply constructed electronic switching device and thus a particularly advantageous sensor device. In conjunction with the additional electrical resistor, which is particularly preferably connected in series with the field-effect transistor along a reference line, this allows for a particularly simple switching between the first reference potential and the second reference potential at the first reference terminal contact.

[0042] For a particularly simple electronic switching device, the further electrical resistor and the control switching device, in particular an associated field-effect transistor, are therefore preferably connected in series along a reference line, wherein preferably a first end of the reference line is connected or connectable to the first terminal, to which in particular the first reference potential is applied, and more preferably a second end of the reference line is connected or connectable to the second terminal, to which in particular the second reference potential is applied.

[0043] In a further advantageous embodiment of a sensor device according to the present invention, in particular in a further development, the field-effect transistor is a metal-oxide-semiconductor field-effect transistor (MOSFET), wherein the second connection contact of the control and evaluation device is preferably connected or connectable to the gate terminal of the field-effect transistor via the second connection line. However, a bipolar transistor is also possible as an alternative.

[0044] However, in most cases, a MOSFET is more advantageous than a comparable bipolar transistor because, compared to a bipolar transistor with comparable other properties, it generally results in a lower voltage drop in the through state, i.e., in the conducting state, compared to a bipolar transistor with comparable other properties. In particular, a lower voltage drop in the conducting state between the drain and source terminals than a bipolar transistor in the through state, i.e., in the conducting state, between the collector and emitter. Due to the lower voltage drop of the MOSFET, the sensor capacitance can be more effectively discharged, i.e., pulled down to a lower voltage level, before establishing potential equalization with the potential applied to the associated reference capacitance after charging.As a result, a larger potential difference between the reference capacitance and the sensor capacitance can be achieved before the potential equalization and thus a higher accuracy of the sensor device, in particular as a result of an improved sensitivity or improved resolution of the sensor device caused by the above effects.

[0045] In a particularly preferred embodiment of a sensor device according to the invention, the drain terminal of the MOSFET is preferably connected or connectable to the first terminal, in particular electrically, ie galvanically, wherein the first reference potential is particularly preferably applied to the first terminal, and the source terminal of the MOSFET is particularly connected to the second terminal, to which a zero potential (0V), in particular ground (GND), is particularly preferably applied.

[0046] If the field effect transistor of the control switching device is a bipolar transistor, the collector terminal of the bipolar transistor is preferably connected or connectable to the first terminal, in particular electrically, ie galvanically, wherein the first reference potential is particularly preferably applied to the first terminal, and the source terminal of the bipolar transistor is particularly connected to the second terminal, to which a zero potential (0V), in particular ground (GND), is particularly preferably applied.

[0047] In a further advantageous embodiment of a sensor device according to the present invention, the sensor device has, in addition to the first electrically conductive sensor electrode, at least one further electrically conductive sensor electrode for capacitively detecting the presence of an input means in a detection area of ​​the sensor device, which likewise forms a sensor capacitance with the environment, in particular a further sensor capacitance in each case, wherein the further sensor capacitance also changes in each case when an input means is present in the detection area of ​​the sensor device, wherein the sensor device preferably further has, for each further sensor electrode, a further first connecting line assigned to the further sensor electrode, a further reference capacitance assigned to the further sensor electrode and a further first electrical resistance assigned to the further sensor electrode.Particularly preferably, the control and evaluation device preferably has, for at least one further sensor electrode, in particular for each further sensor electrode, a further first connection contact assigned to the further sensor electrode, wherein in particular at least one further sensor electrode is connected to the associated, iethis further sensor electrode associated, further first connecting line and via the associated, further first electrical resistor is connected or connectable to the associated further first connecting contact of the control and evaluation device, and wherein the further reference capacitance associated with the at least one further sensor electrode is connected or connectable, on the one hand, between the associated, further first connecting contact and the associated, further first electrical resistor, to the associated, further first connecting line, preferably via a corresponding further first connecting node, and on the other hand is connected or connectable, in particular electrically, ie galvanically, to a or the base potential, preferably a zero potential, in particular a ground potential.

[0048] Particularly preferably, a sensor device configured in this way with a plurality of sensor electrodes further comprises a plurality of analog-to-digital converters for detecting a voltage applied to the connection contact assigned to a respective sensor electrode, in particular to the first connection contact assigned to the respective sensor electrode. This allows the sensor capacitances or their changes to be detected separately for each individual sensor electrode. In a further development, a sensor device according to the present invention is particularly preferably configured such that the sensor capacitances or their changes for all sensor electrodes can be detected separately, in particular simultaneously.

[0049] Using such a sensor device, separate detection of a capacitive approach and / or contact in different areas of a user interface, i.e., spatially resolved, is particularly easy. The multiple sensor electrodes required for this can be integrated into the sensor device particularly easily, particularly with minimal additional effort. In particular, in addition to the respective sensor electrode, only a few additional components or only minor changes / adaptations to the components generally present in a sensor device according to the invention are required.

[0050] In a further, particularly advantageous embodiment of a sensor device according to the present invention, the sensor device further comprises at least one further Schottky diode assigned to a further sensor electrode, wherein the at least one further sensor electrode is connected or connectable via the associated further Schottky diode to a reference connection contact, in particular an associated further reference connection contact, in particular analogous to the first Schottky diode and preferably via at least one associated further reference connection contact, in particular such that the reference potential applied to the further reference connection contact is applied to the further Schottky diode.

[0051] In this case, the respective reference connection contact, in particular the respectively associated further reference connection contact, in particular likewise, can be selectively supplied with a first defined reference potential or a second defined reference potential, wherein the first reference potential is in each case greater than the threshold voltage of the associated further Schottky diode, the second reference potential is in each case smaller than the threshold voltage and the further sensor electrode is connected or connectable via the associated further Schottky diode to the reference connection contact, in particular to the respectively associated further reference connection contact, in such a way that the associated further Schottky diode blocks when the respective first reference potential is applied to the reference connection contact, in particular to the respectively associated further reference connection contact, and opens when the respective second reference potential is applied to the reference connection contact,in particular on the respective additional reference connection contact.

[0052] For this purpose, at least one associated, further reference connection contact is preferably connected or connectable to the first connection and to the second connection, in particular all further, associated reference connection contacts, in particular each via a further or a common reference line. This allows one or more further reference connection contacts to be supplied with a respective first reference potential and a respective second reference potential in a particularly simple manner, wherein the reference potentials and / or the at least one further Schottky diode are each selected such that the respective Schottky diode opens or blocks in a manner analogous to the first Schottky diode depending on the reference potential applied to the respective reference connection contact.

[0053] Like the first Schottky diode, each subsequent Schottky diode has the advantage of having a lower parasitic capacitance than a transistor switching device, such as a MOSFET or a bipolar transistor, and a lower leakage current flowing through the Schottky diode than with a transistor switching device, such as a MOSFET or a bipolar transistor. This allows for higher sensor accuracy, as the lower parasitic capacitance and lower leakage current result in less unwanted influence, particularly distortion, on the sensor capacitance. This advantage increases the more appropriately connected sensor electrodes the sensor device has.

[0054] In principle, however, it is also possible to connect one or more additional sensor electrodes to the reference potential via another switching device, for example via a tri-state switch or a transistor, as proposed in DE 10 2019 128 656, instead of via another Schottky diode, but with the disadvantages of larger parasitic capacitances and larger leakage currents described above.

[0055] For a particularly simple construction of a sensor device according to the invention with more than one sensor electrode, two or more of the reference connection contacts, in particular all reference connection contacts, are particularly preferably connected or connectable to one another, in particular electrically, via a common reference line. This makes it particularly easy to apply the same first reference potential to the respective reference connection contacts simultaneously in a first cycle and / or to the same second reference potential in a second cycle. Separate synchronization is no longer necessary.

[0056] Particularly preferably, a further electrical resistor and a control switching device are connected in series along a reference line and the reference connection contacts are connected or connectable, preferably electrically, to the reference line, in particular between the respective further electrical resistor and the control switching device.

[0057] In a particularly advantageous embodiment of a sensor device according to the present invention, only one common reference line is provided and thus only one further electrical resistor and only one control switching device.

[0058] In a further advantageous embodiment of a sensor device according to the present invention, the sensor device further comprises at least one second electrical resistor associated with a sensor electrode, in particular an ohmic resistor, which is connected in series with the first electrical resistor associated with the respective sensor electrode, so that the sensor electrode is connected or connectable to the associated first connection contact of the control and evaluation device via the associated first connection line, via the associated first electrical resistor and the associated second electrical resistor, wherein preferably the first electrical resistor and the second electrical resistor are selected such that the first electrical resistor is much greater than the second electrical resistor, wherein the first electrical resistor is in particular approximately at least ten times as great,as the second electrical resistor. This allows for improved decoupling of the sensor electrode, particularly stabilizing the discharge of the sensor capacitance.

[0059] Particularly preferably, the first electrical resistance and the second electrical resistance as well as the associated reference capacitance of at least one sensor electrode are selected in particular in such a way, and the sensor electrode is designed in such a way, that the mathematical product of the associated reference capacitance and the associated first electrical resistance is very much greater than the mathematical product of a nominal capacitance of the sensor electrode and the associated second electrical resistance, wherein the product of the associated reference capacitance and the associated first electrical resistance is in particular at least 10 times the product of the nominal capacitance of the sensor electrode and the second electrical resistance. It has been shown that such coordination is particularly advantageous with regard to the achievable detection accuracy of a sensor device according to the invention.

[0060] In a further advantageous embodiment of a sensor device according to the present invention, the first sensor electrode and / or at least one further sensor electrode has a first electrode connection, wherein at least one sensor electrode is connected or connectable via this first electrode connection to the associated first connection line, i.e. the first connection line assigned to this sensor electrode, and via this and via the associated first electrical resistor to the associated first connection contact of the control and evaluation device, and wherein at least one sensor electrode is also connected or connectable via this first electrode connection and via the associated Schottky diode to the associated reference connection contact, preferably in each case with the aid of an associated third connection node and a further connection line and in particular in each case via the second connection node.This allows a particularly simple construction of a sensor device according to the invention to be realized.

[0061] Alternatively, at least one sensor electrode can also have two electrode terminals, as described in more detail, for example, in DE 10 2019 129 802, already mentioned above. This enables, provided the sensor device is suitably designed, a continuity test of the sensor electrode and thus the provision of a sensor device with improved diagnostic properties.

[0062] In a further advantageous embodiment of a sensor device according to the invention, in particular in a further development, the sensor device can further comprise an electrically conductive shielding electrode, in particular a shielding electrode arranged between the first connecting line and the second connecting line, wherein the shielding electrode can preferably and preferably be subjected to a defined electrical potential at least temporarily, in particular permanently, during operation of the sensor device, in particular to a potential that tracks the detected voltage curve over time, and wherein in particular the control and evaluation device is designed to apply a defined potential to the shielding electrode at least temporarily, in particular permanently, during execution of a method according to the invention, in particular to a potential that tracks the detected voltage curve over time.This reduces unwanted interference that could distort the capacitive coupling of the sensor electrode with the environment and / or lead to unwanted interference from other components of the sensor device. As a result, greater accuracy can be achieved with the sensor device.

[0063] In a particularly advantageous embodiment of a sensor device designed according to the present invention, the sensor device is designed and configured to be operated according to a method according to the invention described in more detail below.

[0064] A method according to the invention for operating a sensor device designed according to the present invention is characterized by the steps: a) providing a sensor device according to the invention, b) charging at least one reference capacity, in particular all reference capacities, by applying a defined charging potential to the associated first connection contact of the control and evaluation device, c) discharging at least one sensor capacitance formed with the environment of at least one sensor electrode, in particular all sensor capacitances formed with the environment, by applying a defined reference potential to the associated reference connection contact, preferably a second reference potential, in particular a zero potential, which causes the respective Schottky diode to open, via which the associated sensor electrode is or can be electrically connected to the associated reference connection contact, d) bringing about a potential equalization between at least one reference capacitance and the associated sensor capacitance of the associated sensor electrode, in particular between all reference capacitances and the respectively associated sensor capacitance, wherein for this purpose in particular the associated first connection contact of the control and evaluation device is switched to high impedance and a defined reference potential is applied to the associated reference connection contact, preferably a first reference potential which causes the respective Schottky diode to be blocked, via which the associated sensor electrode is or can be electrically connected to the associated reference connection contact, e) detecting at least one voltage applied to at least one first connection contact of the control and evaluation device, in particular to all first connection contacts, and f) Evaluate the measured voltage.

[0065] Steps b) and c) can be carried out simultaneously or one after the other, with step c) preferably being carried out only after step b), while steps d), e) and f) are carried out one after the other, in particular in the order mentioned, and in particular are only carried out when steps b) and c) have been completed.

[0066] After the potential equalization has been achieved, the voltage established by the potential equalization and subsequently applied, which is also referred to in particular as the equivalent reference voltage, changes when an input device enters the detection area. The resulting voltage change is proportional to the distance of the input device from the sensor electrode, so that the detected voltage can be used to detect whether or not an input device is located in the detection area of ​​the sensor device, in particular at what distance, so that in particular a contact can be distinguished from an approach. Accordingly, by evaluating the voltage, it can be determined whether or not an input device, for example a human hand, is located in the detection area of ​​the sensor device.

[0067] In an advantageous embodiment of a method according to the present invention, in order to apply the charging potential to the first connection contact or to the first connection contacts of the control and evaluation device in step b), the connection contact is switched as an output, in particular by switching it to a low resistance, i.e., to "LOW." This enables particularly efficient charging of the associated reference capacitance(s).

[0068] In a further advantageous embodiment of a sensor device according to the present invention, the sensor device is therefore particularly designed and configured such that, in order to apply the charging potential to one of the first connection contacts of the control and evaluation device in step b), the first connection contact can be switched as an output, wherein for this purpose, in particular, the first connection contact can be switched to a low-resistance state.

[0069] The switching of the two connection contacts can be implemented particularly easily by means of a control and evaluation device in which the first connection contact and the second connection contact are each part of a so-called GPIO connection (“General Purpose Input / Output connection”), i.e. as a general, switchable connection contact, which can be achieved particularly easily by assigning the respective connection contact to an input and / or output port, in particular a switchable input and / or output port.

[0070] Preferably, particularly in a further development, the first connection contact and the second connection contact are assigned to a common input and / or output port, i.e. a common channel which preferably allows different assignments, e.g. with different potentials etc., but in particular can logically only be controlled together. If the first connection contact and the second connection contact are each assigned to one and the same input and / or output port, synchronization of the two connection contacts can be achieved in a particularly simple manner, whereby short sampling cycles and thus high resolution can be achieved. Furthermore, high sensor sensitivity can be achieved in this way, since the synchronization allows a defined initial state to be set reliably and precisely before the start of each measurement.Alternatively, it is also conceivable to assign the two connection contacts to different input and / or output ports.

[0071] In a particularly advantageous embodiment of a sensor device according to the invention, the sensor device has a first analog-digital converter and at least one second analog-digital converter formed separately from the first analog-digital converter, wherein each of the two analog-digital converters can preferably be coupled, in particular electrically connected, to at least one input and / or output port.

[0072] If two or more analog-to-digital converters are provided, these can be assigned either to the same input and / or output port, to different input and / or output ports and / or to different control and evaluation devices, wherein for the latter, the sensor device preferably has more than one control and evaluation device.

[0073] In a further step of a method according to the invention, in particular in an advantageous embodiment of a method according to the invention, a sensor signal can be generated and output depending on the evaluation result, which sensor signal in particular contains at least one piece of signal information as to whether an input means is located in the detection range of the sensor device or not.

[0074] In a particularly advantageous embodiment of a method according to the present invention, in order to apply the defined reference potential in steps c) and d) to the associated reference connection contact, the control switching device is preferably controlled via the second connection contact of the control and evaluation device and the second connection line from the control and evaluation device, wherein in order to apply a reference potential which causes the respective Schottky diode to block, via which the associated sensor electrode is or can be electrically connected to the associated reference connection contact, in particular for applying a first reference potential, and thus for bringing about the potential equalization in step d), the control switching device is preferably switched to a first switching state, in particular to a high-resistance and thus non-conductive, blocked switching state, or is held in this,and wherein, for applying a reference potential which causes the respective Schottky diode to open, via which the associated sensor electrode is or can be electrically connected to the associated reference connection contact, in particular for applying a second reference potential, and thus for discharging at least one sensor capacitance formed with the environment of at least one sensor electrode in step b), the control switching device is preferably switched to a second switching state, in particular to a low-resistance and thus conductive, open switching state, or is held in this state.

[0075] This allows the respective reference connection contact to be applied to the respective desired reference potential in a particularly simple manner. If the reference connection contacts are each connected to one another via a common reference line, only a second connection contact, a second control line, and only one control switching device are required to switch between the first reference potential and the second reference potential at the reference connection contacts. This makes it possible to provide a particularly simple and advantageous sensor device, in particular one comprising only a few components and thus particularly cost-effective.

[0076] The preferred embodiments presented with reference to a capacitive sensor device according to the invention and their advantages also apply accordingly to a method according to the invention for operating such a sensor device and vice versa, even if this is not explicitly explained in the present application, in particular to avoid repetition.

[0077] Further features of the invention emerge from the claims, the figures, and the description of the figures. All features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combination, but also in other combinations or even on their own, provided that this combination is technically feasible.

[0078] The invention will now be explained in more detail using several non-limiting embodiments and with reference to the accompanying drawings, wherein functionally identical components are each provided with the same reference numerals. Showing: Fig. 1 is a block diagram of a capacitive sensor device known from the prior art, Fig. 2 a block diagram of a first embodiment of a capacitive sensor device according to the invention, Fig. 3 a block diagram of a second embodiment of a capacitive sensor device according to the invention, Fig. 4 is a diagram in which, for an embodiment of a Schottky diode, a curve of an internal, parasitic capacitance of the Schottky diode is shown as a function of a voltage applied to the Schottky diode, Fig. 5 is a block diagram of a third embodiment of a capacitive sensor device according to the invention, and Fig. 6 a block diagram of a fourth embodiment of a capacitive sensor device according to the invention.

[0079] Fig. 1 shows a block diagram of a sensor device 1 of the type known from the prior art, as described, for example, in DE 10 2019 128 656, wherein the sensor device 1 has two electrically conductive sensor electrodes 3 for capacitively detecting the presence of an input device in a detection area of ​​the sensor device 1, wherein the sensor electrodes 3 each form a sensor capacitance 4 with the environment that changes when an input device is present in the detection area of ​​the sensor device 1. Furthermore, the capacitive sensor device 1 has a control and evaluation device 8, which has two first connection contacts 9 and a second connection contact 10, and which is connected both to a zero potential, in this case to ground (GND), in particular electrically, iegalvanic, and which is further connected or connectable to a supply voltage, for example a supply voltage in a vehicle of in particular +12V or the like, which, however, is not specified in . Fig. 1 is not shown.

[0080] The Fig. The sensor device 1 shown in Fig. 1 has a plurality of first connecting lines 11, each of which is connected to the first connecting contact 9 and in particular serves as a measuring line 11, wherein the sensor electrodes 3 are each connected to the respectively associated first connecting contact 9 of the control and evaluation device 8 via these first connecting lines 11 and an electrical resistor 7, which is in particular an ohmic resistor and is connected along these lines.

[0081] Furthermore, a reference capacitance 5 is connected via a first connection node 14 on the one hand to the first connection line 11 and on the other hand to a base potential, in this case to a ground potential GND, ie to a zero potential (0V).

[0082] The sensor electrodes 3 can also each be connected to a ground potential via a second connection node 12 and an electronic switching device 6.

[0083] At the Fig. 1, the two electronic switching devices 6 can each be controlled by means of a common second connecting line 13, which serves in particular as a control line, wherein the associated control signal can be generated by the control and evaluation device 8 and can be output via a second connecting contact 10 to the second connecting line 13, ie the control line 13.

[0084] The Fig. The sensor device 1 shown in Figure 1 can in particular be operated according to the CVD method, which is also basically known from the prior art, wherein for this purpose, in a first step, the reference capacitors 5 can each be charged in a defined manner via the first connection contacts 9 and the first connection line 11 with a defined charging potential, and the sensor electrodes 3 or the sensor capacitors 4 formed by them with the environment are each discharged by connecting them to a ground potential (GND), wherein for this purpose the associated electronic switching devices 6 can each be controlled by the control and evaluation device 8 via the second connection contact 10 and the common control line 13 in such a way that the switches of the electronic switching devices 6 close, wherein the electronic switching devices 6 each have, in particular, a transistor or a tri-state switch as the corresponding switching element.

[0085] In a next step, in particular after the reference capacitances 5 have been fully and definedly charged and the sensor electrodes 3 or the sensor capacitances 4 formed by them with the environment have been discharged in a defined manner, in particular almost completely, the connections of the sensor electrodes 3 to the ground potential are separated, wherein for this purpose the electronic switching devices 6 can be controlled accordingly by the control and evaluation device 8, in particular can be switched over in such a way that the connection between the second connection node 12 and the ground potential is separated.

[0086] Furthermore, the first connection lines 11 or the first connection contacts 9 can be separated from the charging potential, which can be easily achieved, for example, using corresponding GPIO inputs and outputs by switching them to high impedance.

[0087] As a result, a potential equalization occurs between the respective reference capacitance 5 and the associated sensor capacitance 4 of a sensor electrode 3 and an equivalent reference voltage is established.

[0088] If a corresponding input means is now brought into the environment of one of the sensor electrodes 3, in particular into its detection range, the capacitive coupling of the sensor electrode 3 with the environment changes and, as a result, the reference voltage set by the potential equalization changes, which can be measured by the control and evaluation device 8 via the associated first connecting line 11, which serves as the measuring line 11.

[0089] For this purpose, the control and evaluation device 8 can, for example, have corresponding devices (not shown here) for detecting the change in the capacitive coupling of the sensor electrode 3 with the environment, for example one or more analog-digital converters, which can be connected to the corresponding first connecting lines 11 or the associated first connecting contacts 9, in particular after the potential equalization has been effected.

[0090] Fig. 2 shows a block diagram of a first exemplary embodiment of a capacitive sensor device 100 according to the invention, wherein the sensor device 100 is provided for an operating device of a vehicle (not shown here), for example for a steering wheel operating device, which can be actuated in particular at least partially by an approach of an input means to a user interface and / or by a touch of a user interface with an input means, wherein the detection of an approach and / or a touch of the user interface takes place capacitively.

[0091] According to the invention, the sensor device 100 has a first electrically conductive sensor electrode E1 for capacitively detecting the presence of an input means, such as a human hand or a finger of a human hand, in a detection area of ​​the sensor device 100, wherein the sensor electrode E1 has a sensor capacitance Cex-1 which changes in the presence of a suitable input means in the detection area of ​​the sensor device 100, for example in the presence of a human hand.

[0092] Furthermore, the sensor device 100 has a control and evaluation device 8 with a first connection contact 9 and a first connection line 11, which serves in particular as a measuring line 11, wherein the control and evaluation device 8 in this case is in particular a microcontroller and the first sensor electrode E1 is connected via the first connection line 11 to the first connection contact 9 of the control and evaluation device 8.

[0093] This embodiment of a sensor device 100 according to the invention further comprises a second connection contact 10 and a second connection line 13, which serves in particular as a control line 13.

[0094] According to the invention, the sensor device 100 further comprises a first reference capacitance C Ref-1 which is connected by a capacitor C Ref-1 with a defined capacitance, and which is electrically connected on the one hand to the first connecting line 11, in particular between the first connection contact 9 of the control and evaluation device 8 and the sensor electrode E1, in particular via a first connection node 14, and on the other hand to a base potential V BASIS , which in this case is preferably a ground potential (GND), ie a zero potential (0V).

[0095] Between the first reference capacity C Ref-1 and the sensor electrode E1, a first electrical resistor R1, in this case an ohmic resistor R1, is further connected in series according to the present invention, in particular between the first connection node 14, via which the first reference capacitance C Ref-1is electrically connected to the first connecting line 11, and the sensor electrode E1.

[0096] For its electrical contacting, the sensor electrode E1 has a first electrical electrode connection 17, via which the first sensor electrode E1 is connected to the first connecting line 11 and the first connecting contact 9 of the control and evaluation device 8.

[0097] According to the present invention, the sensor device 100 further comprises at least one first Schottky diode D1, via which the first sensor electrode E1 is further connected to a first reference connection contact 15A, wherein the first reference connection contact 15A is optionally connected to a first defined reference potential V Ref1 or a second defined reference potential V Ref2 can be applied.

[0098] In this exemplary embodiment of a sensor device 100 according to the invention, the sensor electrode E1 is connected to the associated reference connection contact 15A via its first electrode connection 17, a section of the first connection line 11, a second connection node 12 and a further electrical line 16 and the first Schottky diode D1.

[0099] This first Schottky diode D1 is connected to the first reference terminal contact 15A in such a way that it blocks when the reference potential applied to this reference terminal contact 15A is greater than the threshold voltage of this Schottky diode D1, and that it opens when the reference potential applied to this first reference terminal contact 15A is less than the threshold voltage of this Schottky diode D1. This can be used, comparable to the electronic switching device 6 of Fig. 1, discharging the sensor capacitance C ex-1the sensor electrode E1.

[0100] To control the reference potential V applied to the first reference connection contact 15A Ref1 or V Ref2 , in this embodiment of a sensor device 100 according to the invention, an electronic switching device 6 is also provided, which is designed and configured to be switched between a first switching state and a second switching state, wherein, when the electronic switching device 6 is in the first switching state, the first reference potential V Ref1 at the first reference terminal contact 15A, so that the first Schottky diode D1 is blocked, and when the electronic switching device 6 is in the second switching state, the second reference potential V Ref2 at the first reference terminal 15A, so that the first Schottky diode D1 opens.

[0101] In this case, the electronic switching device 6 has a control switching device S0 in the form of a MOSFET S0, the drain terminal of which is connected via a first section of a reference line 15 and a further electrical resistor R0, in particular an ohmic resistor R0, which in the present case serves as a pull-up resistor R0, to a first terminal at which the first reference potential V Ref1 which in this example is +5V. The source terminal of the MOSFET S0 is connected via a second section of the reference line 15 to a second terminal at which the second reference potential V Ref2 which in this example is a ground potential GND.

[0102] The control switching device S0, in this case the MOSFET S0, in particular its gate terminal, is connected via the second connecting line 13, which serves in particular as a control line, to the second connection contact 10 of the control and evaluation device 8, wherein the control and evaluation device 8 is designed and configured to switch the control switching device S0 between a first switching state and a second switching state, wherein a switchover to the first switching state, in which the MOSFET S0 is blocked, causes the first reference potential V Ref1 and switching to the second switching state, in which the MOSFET S0 is in a through state, ie a conductive state, that the second reference potential V Ref2 sets.

[0103] This exemplary embodiment of a sensor device 100 according to the invention is further designed to carry out a method according to the invention, which will be described in more detail below, wherein the sensor device 100, in particular the control and evaluation device 8, is also designed and configured to detect and evaluate a voltage at the first connection contact 9, wherein the control and evaluation device 8 in this exemplary embodiment has a switchable input and output for this purpose, in particular a GPIO connection contact 9, which can be switched optionally as an input or output, which is to be symbolized by the switch S1, and an analog-digital converter ADC1, which can be connected to the first connection contact 9.

[0104] To operate the Fig. 2 according to a method according to the invention, the following steps are carried out: a) Providing the sensor device 100, b) Charging the first reference capacity C Ref-1 by applying a defined charging potential to the associated first connection contact 9 of the control and evaluation device 8, in particular by means of the switching device S1, c) Discharge of the first sensor capacitance C formed with the environment ex-1 , the first sensor electrode E1, by the second defined reference potential V Ref2 , which in this case is a ground potential GND, is applied to the associated first reference terminal contact 15A, which causes the first Schottky diode D1 to open, via which the associated sensor electrode E1 is electrically connected to the associated reference terminal contact 15A, d) Bringing about a potential equalization between at least the first reference capacitance C Ref-1 and the first sensor capacitance C ex-1the first sensor electrode E1, wherein for this purpose in particular the associated first connection contact 9 of the control and evaluation device 8 is switched to high resistance and the defined first reference potential V Ref1 , which in this case is +5V, is applied to the first reference terminal 15A, which causes the first Schottky diode D1 to block, e) detecting the voltage applied to the first connection contact 9 of the control and evaluation device 8 by means of the first analog-digital converter ADC1, and f) Evaluate the measured voltage.

[0105] To apply the defined reference potential V Ref1 , V Ref2in steps c) and d) at the associated first reference connection contact 15A, the control switching device S0 is controlled accordingly via the second connection contact 10 of the control and evaluation device 8 and the second connection line 13 by the control and evaluation device 8, wherein for applying the first reference potential V Ref1 , which causes the first Schottky diode D1 to block and thus, to bring about the potential equalization in step d), the control switching device S0 is switched into a first switching state or is kept in this state, and to apply the second reference potential V Ref2 , which causes the first Schottky diode D1 to open and thus to discharge the first sensor capacitance C ex-1 the first sensor electrode E1 in step c), the control switching device S0 is switched into a second switching state or is held in this state.

[0106] Fig. 3 shows a block diagram of a second embodiment 200 of a sensor device according to the invention, in which the first sensor electrode E1 has, in addition to the first electrode terminal 17, a second electrode terminal 18, via which the sensor electrode E1 is connected in this case to the associated Schottky diode D1 and via this to the associated reference connection node 15A. This enables at least a partial continuity test of the sensor electrode E1, in some cases a complete continuity test, depending on the design of the sensor electrode E1, wherein the sensor electrode E1 is particularly preferably as shown in the Fig. 4a and Fig. 4b of DE 10 2019 129 802.

[0107] Fig. 4 shows a diagram in which an embodiment of a Schottky diode D1, D2, D3, (cf. Fig. 1 to 3 and 5 and 6) a curve of an internal, parasitic capacitance of the Schottky diode D1, D2, D3 is shown as a function of a voltage applied to the Schottky diode D1, D2, D3, in order to illustrate that it is advantageous for high measurement accuracy if the highest possible voltage is applied to the Schottky diode D1, D2, D3 at the time of measurement in order to have the lowest possible parasitic capacitance that negatively influences the measurement accuracy.

[0108] Fig. Fig. 5 shows a block diagram of a third embodiment of a capacitive sensor device 300 according to the invention, wherein this sensor device 300 has, in addition to the first electrically conductive sensor electrode E1, two further electrically conductive sensor electrodes E2, E3 for capacitively detecting the presence of an input means in a detection area of ​​the sensor device 300, which also each have a further sensor capacitance Cex-2 , C ex-3 form, wherein the sensor device 300 further comprises for each further sensor electrode E2, E3 a further first connecting line 11B, 11C assigned to the respective further sensor electrode E2, E3, a further reference capacitance C assigned to the respective further sensor electrode E2, E3 Ref-2 , C Ref-3 , and each has a further first electrical resistor R2, R3 assigned to the respective further sensor electrode E2, E3. The control and evaluation device 8 further comprises, for each further sensor electrode E2, E3, a further first connection contact 9B, 9C assigned to the respective further sensor electrode E2, E3, and each further sensor electrode E2, E3 is connected to the associated further first connection contact 9B, 9C of the control and evaluation device 8 via the associated, respective further first connection line 11B, 11C and via the associated, further first electrical resistor R2, R3; R1B, R1C.

[0109] The further reference capacitances C belonging to the further sensor electrodes E2, E3 are Ref-2 , C Ref-3 on the one hand, each connected between the associated, further first connection contact 9B, 9C and the associated, further first electrical resistor R2, R3 with the associated, further first connection line 11B, 11C and on the other hand with the base potential V Basis .

[0110] Each of the further sensor electrodes E2, E3 is further connected via a further Schottky diode D2, D3 to an associated reference connection contact 15B, 15C, wherein in this embodiment the individual reference connection contacts 15A, 15B and 15C are each connected via a common reference line 15 and are each simultaneously connected to the first reference potential V Ref1 or the second reference potential V Ref2 can be applied, whereby a particularly simple sensor device 300 can be provided which simultaneously enables spatially resolved capacitive detection, wherein for this purpose a separate analog-digital converter ADC1 is assigned to each first connection contact 9A, 9B, 9C.

[0111] Fig.6 shows a block diagram of a fourth exemplary embodiment of a capacitive sensor device 400 according to the invention, wherein this sensor device 400 further comprises, for each sensor electrode E1, E2, E3, a second electrical resistor R2A, R2B, R2C assigned thereto, which is connected in series with the first electrical resistor R1A, R1B, R1C assigned to the respective sensor electrode E1, E2, E3, so that the sensor electrodes E1, E2, E3 are each connected to the associated first connection contact 9A, 9B, 9C of the control and evaluation device 8 via the associated first connection line 11A, 11B, 11C, via the associated first electrical resistor R1A, R1B, R1C and the associated second electrical resistor R2A, R2B, R2C. The first electrical resistance R1A, R1B, R1C and the second electrical resistance R2A, R2B, R2C are selected in this case such that the first electrical resistance R1A, R1B, R1C is in each case approximately at least ten times as large as the associated second electrical resistance R2A, R2B, R2C, in particular so that the condition C Refx * R1x >> C ex-x * R2x is fulfilled.

[0112] If steps b) and d) of a method according to the invention are carried out simultaneously, a switching state of the sensor device 400 required for this purpose is particularly preferably maintained at least for a time t1 = C ex·x * Maintain R2x.

[0113] The switching state for bringing about the potential equalization in step d) is preferably at least for a time t2 = C Refx * (R1x+R2x) must be maintained before starting the actual measurement.

[0114] This makes it easy to ensure that the reference capacities C Ref-1 , C Ref-2 , C Ref-3 , sufficient discharging of the sensor capacitances C ex-1 , C ex-2 , C ex-3 and sufficient potential equalization must take place.

[0115] The following applies to the voltage Vx, which is measured depending on the capacitive coupling of a sensor electrode Ex with the environment: Vx=(CRefx*VRef1+Cex−x*VRef2) / (CRefx+Cex−x)

[0116] If VRef2 = 0V, ie selected as GND, as in the described embodiments, the result is: Cex−x=CRefx*(VRef1−Vx) / Vx, and thus a particularly simple determination of the respective capacitive coupling of a sensor electrode Ex with the environment. List of reference symbols: 1 capacitive sensor device from the state of the art 100, 200, 300, 400 capacitive sensor device according to the invention 3 Sensor electrode 4 Sensor capacitance (capacitance of the sensor electrode with the environment) 5 Reference capacity 6 electronic switching device 7 electrical resistance, especially pull-up resistance 8 Control and evaluation device 9, 9A, 9B, 9C first connection contact 10 second connection contact 11, 11A, 11B, 11C first connecting cable (measuring cable) 12, 12A, 12B, 12C second connection node 13 second connection cable (control cable) 14, 14A, 14B, 14C first connection node 15 Reference line 15A, 15B, 15C Reference connection nodes 16, 16A, 16B, 16C additional connection cable 17 first electrode connection 18 second electrode connection Cex -1, C ex-2 , C ex-3Sensor capacitance (capacitance of the first sensor electrode with the environment) C Ref-1 , C Ref-2 , C Ref-3 Reference capacity ADC1, ADC2, ADC3 analog-to-digital converters D1, D2, D3 Schottky diode E1, E2, E3 sensor electrode GND ground potential R0 additional electrical resistance (especially pull-up resistor) R1, R2, R3, first electrical resistance R1A, R1B, R1C R2A, R2B, R2C second electrical resistance S0 control switching element S1, S2, S3 electronic switching device for controlling a GPIO output on the respective first connection contact V Basis Base potential V Ref1 first reference potential V Ref2 second reference potential

Claims

[1] Capacitive sensor device (100, 200, 300, 400) for an operating device of a vehicle for detecting an approach and / or contact, comprising: - a first electrically conductive sensor electrode (E1) for capacitively detecting the presence of an input means in a detection area of ​​the sensor device (100, 200, 300, 400), wherein the sensor electrode (E1) has a sensor capacitance (C ex-1 ) trains, - a control and evaluation device (8) with a first connection contact (9, 9A), - a first connecting line (11, 11A), - a first reference capacity (C Ref-1 ), - a first electrical resistance (R1, R1A), and - one with a defined reference potential (V Ref1 , V Ref2) loadable first reference connection contact (15A), wherein the first sensor electrode (E1) is connected via the first connection line (11, 11A) and via the first electrical resistor (R1, R1A) to the first connection contact (9, 9A) of the control and evaluation device (8), and where the first reference capacity (C Ref-1 ) is connected to the first connecting line (11, 11A) between the first connection contact (9, 9A) and the first electrical resistor (R1, R1A) and is connected to a base potential (V Basis ) is connected, characterized by that the sensor device (100, 200, 300, 400) further comprises at least one first Schottky diode (D1), via which the first sensor electrode (E1) is further connected to the first reference terminal contact (15A), wherein the first reference connection contact (15A) is optionally connected to a first defined reference potential (V Ref1) or a second defined reference potential (V Ref2 ) can be loaded, where the first reference potential (V Ref1 ) is greater than the threshold voltage of the first Schottky diode (D1) and the first sensor electrode (E1) is connected to the first reference terminal (15A) via the first Schottky diode (D1) in such a way that the first Schottky diode (D1) is blocked when the first reference potential (V Ref1 ) is applied to the first reference terminal (15A), and where the second reference potential (V Ref2 ) is smaller than the threshold voltage of the first Schottky diode (D1) and the first sensor electrode (E1) is connected to the first reference terminal (15A) via the first Schottky diode (D1) in such a way that the first Schottky diode (D1) opens when the second reference potential (V Ref2 ) is applied to the first reference connection contact (15A). [2] Sensor device (100, 200, 300, 400) according to claim 1, characterized by that the sensor device (100, 200, 300, 400) further comprises an electronic switching device (6) which is designed and configured to be switched between a first switching state and a second switching state, wherein, when the electronic switching device (6) is in the first switching state, the first reference potential (V Ref1 ) is applied to the first reference terminal contact (15A), so that the first Schottky diode (D1) is blocked, and when the electronic switching device (6) is in the second switching state, the second reference potential (V Ref2 ) is applied to the first reference terminal (15A), so that the first Schottky diode (D1) opens. [3] Sensor device (100, 200, 300, 400) according to claim 1 or 2, characterized bythat the electronic switching device (6) has a control switching device (S0) which can be switched from a first switching state to a second switching state, wherein switching to the first switching state causes the first reference potential (V Ref1 ) and switching to the second switching state causes the second reference potential (V Ref2 ) is set. [4] Sensor device (100, 200, 300, 400) according to claim 3, characterized by that the sensor device (100, 200, 300, 400) further comprises a first terminal to which the first reference potential (V Ref1 ) is applied, and a second terminal to which the second reference potential (V Ref2 ), wherein the first reference terminal contact (15A) is connectable to the first terminal and to the second terminal. [5] Sensor device (100, 200, 300, 400) according to claim 4, characterized by that the sensor device (100, 200, 300, 400) has at least one further electrical resistor (R0), wherein the first reference connection contact (15A) is connected to the first terminal via this further electrical resistor (R0). [6] Sensor device (100, 200, 300, 400) according to claim 3 and one of claims 4 or 5, characterized by that the first reference terminal contact (15A) is connected to the second terminal via the control switching device (S0). [7] Sensor device (100, 200, 300, 400) according to one of claims 3 to 6, characterized bythat the sensor device (100, 200, 300, 400) further comprises a second connecting line (13) and the control and evaluation device (8) further comprises a second connecting contact (10), wherein the control switching device (S0) is connected to the second connecting contact (10) of the control and evaluation device (8) via the second connecting line (13), and wherein the control and evaluation device (8) is designed and configured to switch the control switching device (S0) at least between a first switching state and a second switching state. [8] Sensor device (100, 200, 300, 400) according to one of claims 3 to 7, characterized by that the control switching device (S0) has or is a field effect transistor (S0). [9] Sensor device (100, 200, 300, 400) according to claim 8, characterized bythat the field-effect transistor (S0) is a metal-oxide-semiconductor field-effect transistor, wherein the second connection contact (10) of the control and evaluation device (8) is connected to the gate connection of the field-effect transistor (S0) via the second connection line (13). [10] Sensor device (300, 400) according to one of the preceding claims, characterized by that the sensor device (300, 400) has, in addition to the first electrically conductive sensor electrode (E1), at least one further electrically conductive sensor electrode (E2, E3) for capacitively detecting the presence of an input means in a detection area of ​​the sensor device (300, 400), which also has a further sensor capacitance (C ex-2 , C ex-3 ) trains, wherein the sensor device (300, 400) for each further sensor electrode (E2, E3), further - a further first connecting line (11B, 11C) associated with the further sensor electrode (E2, E3), - a further reference capacitance (C Ref-2 , C Ref-3 ), and - a further first electrical resistor (R2, R3) associated with the further sensor electrode (E2, E3), has, wherein the control and evaluation device (8) further comprises, for each further sensor electrode (E2, E3), a further first connection contact (9B, 9C) associated with the further sensor electrode (E2, E3), wherein at least one further sensor electrode (E2, E3) is connected to the associated further first connection contact (9B, 9C) of the control and evaluation device via the associated further first connection line (11B, 11C) and via the associated further first electrical resistor (R2, R3; R1B, R1C), wherein the further reference capacitance (C Ref-2 , C Ref-3 ) is connected, on the one hand, between the associated, further first connection contact (9B, 9C) and the associated, further first electrical resistor (R2, R3; R1B, R1C) to the associated, further first connection line (11B, 11C) and, on the other hand, to a or the base potential (V Basls ) is connected. [11] Sensor device (300, 400) according to claim 10, characterized by that the sensor device (300, 400) further comprises at least one further Schottky diode (D2, D3) associated with a further sensor electrode (E2, E3), wherein the at least one further sensor electrode (E2, E3) is connected to a reference connection contact (15B, 15C) via the associated further Schottky diode (D2, D3), wherein the reference connection contact (15A, 15B, 15C) is optionally connected to a respective first defined reference potential (VRef1 ) or a respective second defined reference potential (V Ref2 ) can be loaded, where the respective first reference potential (V Ref1 ) is greater than the threshold voltage of the corresponding further Schottky diode (D2, D3), the respective second reference potential (V Ref2 ) is smaller than the threshold voltage, and the further sensor electrode (E2, E3) is connected to the reference connection contact (15A, 15B, 15C) via the associated further Schottky diode (D2, D3) in such a way that the associated further Schottky diode (D1) blocks when the respective first reference potential (V Ref1 ) is applied to the reference connection contact (15A,15B, 15C) and opens when the respective second reference potential (V Ref2 ) is applied to the reference connection contact (15A,15B, 15C). [12] Sensor device (300, 400) according to one of the preceding claims, characterized bythat the sensor device (400) further comprises a second electrical resistor (R2A, R2B, R2C) associated with at least one sensor electrode (E1, E2, E3), which is connected in series with the first electrical resistor (R1A, R1B, R1C) associated with the respective sensor electrode (E1, E2, E3), so that the sensor electrode (E1, E2, E3) is connected via the associated first connecting line (11A, 11B, 11C), via the associated first electrical resistor (R1A, R1B, R1C) and the associated second electrical resistor (R2A, R2B, R2C) to the associated first connection contact (9A, 9B, 9C) of the control and evaluation device (8), wherein the first electrical resistor (R1A, R1B, R1C) and the second electrical resistor (R2A, R2B, R2C) are selected such are that the first electrical resistance (R1A, R1B, R1C) is approximately at least ten times as large as the second electrical resistance (R2A, R2B, R2C). [13] Sensor device (100, 300, 400) according to one of the preceding claims, characterized by that the first sensor electrode (E1) or at least one further sensor electrode (E2, E3) has a first electrode terminal (17), wherein at least one sensor electrode (E1, E2, E3) is connected via this first electrode connection (17) to the associated first connecting line (11, 11A, 11B, 11C) and via this and via the associated first electrical resistor (R1, R2, R3; R1A, R1B, R1C) to the associated first connecting contact (9, 9A, 9B, 9C) of the control and evaluation device (8), and wherein at least one sensor electrode (E1, E2, E3) is also connected to the associated reference terminal contact (15A) via this first electrode terminal (17) and via the associated Schottky diode (D1, D2, D3). [14] Method for operating a capacitive sensor device (100, 200, 300, 400) designed according to one of claims 1 to 13, characterized by the steps: a) providing a sensor device designed according to one of claims 1 to 13, b) Charging at least one reference capacity (C Ref-1 , C Ref-2 , C Ref-3 ) by applying a defined charging potential to the associated first connection contact (9, 9A, 9B, 9C) of the control and evaluation device (8), c) discharging at least one sensor capacitance formed with the environment (C ex-1 , C ex-2 , C ex-3 ) at least one sensor electrode (E1, E2, E3), by applying a defined reference potential (V Ref2) is applied to the associated reference connection contact (15A), which causes the respective Schottky diode (D1, D2, D3) to open, via which the associated sensor electrode (E1, E2, E3) can be electrically connected to the associated reference connection contact (15A, 15B, 15C), d) bringing about a potential equalization between at least one reference capacitance (C Ref-1 , C Ref-2 , C Ref-3 ) and the corresponding sensor capacitance (C ex -1, C ex-2 , C ex-3 ) of the associated sensor electrode (E1, E2, E3), wherein for this purpose the associated first connection contact (9, 9A, 9B, 9C) of the control and evaluation device (8) is switched to high resistance and a defined reference potential (V Ref1) is applied to the associated reference connection contact (15A, 15B, 15C), which causes the respective Schottky diode (D1, D2, D3) to block, via which the associated sensor electrode (E1, E2, E3) can be electrically connected to the associated reference connection contact (15A, 15B, 15C), e) detecting at least one voltage applied to at least one first connection contact (9, 9A, 9B, 9C) of the control and evaluation device (8), and f) Evaluate the measured voltage. [15] Method according to claim 14, wherein the sensor device (100, 200, 300, 400) is designed according to one of claims 7 to 13, characterized by that to apply the defined reference potential (V Ref1 , V Ref2) in steps c) and d) at the associated reference connection contact (15A, 15B, 15C), the control switching device (S0) is controlled accordingly via the second connection contact (10) of the control and evaluation device (8) and the second connection line (13) of the control and evaluation device (8), where to apply a reference potential (V Ref1 ), which causes the respective Schottky diode (D1, D2, D3) to be blocked, via which the associated sensor electrode (E1, E2, E3) is electrically connectable to the associated reference connection contact (15A, 15B, 15C), and thus to bring about the potential equalization in step d), the control switching device (S0) is switched into a first switching state or is held in this state, and where to apply a reference potential (V Ref2), which causes the respective Schottky diode (D1, D2, D3) to open, via which the associated sensor electrode (E1, E2, E3) can be electrically connected to the associated reference connection contact (15A, 15B, 15C) and thus to discharge at least one sensor capacitance (C ex-1 , C ex-2 , C ex-3 ) at least one sensor electrode (E1, E2, E3) in step c), the control switching device (S0) is switched into a second switching state or is held in this.

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