阅读说明：本技术 用于车辆的电容式传感器机构的组件 (Assembly of a capacitive sensor mechanism for a vehicle ) 是由 贝特霍尔德·西格 于 2019-02-27 设计创作，主要内容包括：本发明涉及一种用于车辆(1)的电容式传感器机构(20)的组件(10),其尤其用于在电容式传感器机构(20)中的驱动和/或评估以检测车辆(1)处的激活行为,具有：至少一个用于测知车辆(1)环境变化的传感器电极(20.1)；传输机构(30),用于依据频率和/或相位传输电输入信号(E)并用于输出输出信号(A)；传输机构(30)的输出端(30.2),其电连接至传感器电极(20.1)以在传感器电极(20.1)输出该输出信号(A)用以检测；该传输机构(30)具有受控的源机构(30.3),用于根据输入信号(E)的依据频率和/或相位的传输来在传感器电极(20.1)作为被引导的电信号输出输出信号(A)。(The invention relates to an assembly (10) for a capacitive sensor system (20) of a vehicle (1), in particular for driving and/or evaluating in the capacitive sensor system (20) for detecting an activation behavior at the vehicle (1), having: at least one sensor electrode (20.1) for detecting environmental changes of the vehicle (1); -transmission means (30) for transmitting an electrical input signal (E) in terms of frequency and/or phase and for outputting an output signal (a); an output (30.2) of the transmission means (30), which is electrically connected to the sensor electrode (20.1) for outputting the output signal (a) at the sensor electrode (20.1) for detection; the transmission means (30) have controlled source means (30.3) for outputting an output signal (A) as a guided electrical signal at the sensor electrode (20.1) as a function of the frequency and/or phase-dependent transmission of the input signal (E).)

1. An assembly (10) for a capacitive sensor device (20) of a vehicle (1), in particular for driving and/or evaluating in the capacitive sensor device (20) for detecting an activation behavior at the vehicle (1), having:

-at least one sensor electrode (20.1) for sensing environmental changes of the vehicle (1),

-transmission means (30) for transmitting an electrical input signal (E) in terms of frequency and/or in terms of phase and for outputting an output signal (A),

-an output (30.2) of the transmission means (30) electrically connected to the sensor electrode (20.1) for outputting the output signal (A) at said sensor electrode (20.1),

wherein the transmission means (30) have controlled source means (30.3) for generating the output signal (A) in dependence on a frequency-dependent and/or phase-dependent transmission of the input signal (E).

2. Assembly (10) according to claim 1, characterized in that the source means (30.3) are designed as a true low-resistance controlled current and/or voltage source for outputting the generated output signal (a) as a directed electrical signal at the sensor electrode (20.1).

3. Assembly (10) according to one of the preceding claims, characterized in that the source means (30.3) are designed as active components, preferably as operational amplifiers (OP), wherein the source means (30.3) are directly connected to supply voltages (VC, VE) for actively generating the output signal (a).

4. Assembly (10) according to one of the preceding claims, characterized in that the transmission means (30) have at least one filter element (30.4,30.5) for forming an electronic filter, preferably a low-pass filter and/or an all-pass filter and/or a band-pass filter, for performing a frequency-dependent and/or phase-dependent transmission of the input signal (E), wherein the source means (30.3) are preferably connected to at least one filter element (30.4,30.5) for forming an active filter, particularly preferably a Sallen-Key filter.

5. Assembly (10) according to one of the preceding claims, characterized in that the transmission means (30) have a first filter element (30.4), in particular for forming an RC low-pass filter, preferably a first order filter, and a second filter element (30.5), in particular for forming a salen-Key filter, preferably a second order filter, wherein the filter elements (30.4,30.5) are connected to each other for jointly performing a frequency-dependent and/or phase-dependent transmission of the input signal (E) and/or for increasing the filter order of the transmission means (30).

6. Assembly (10) according to one of the preceding claims, characterized in that the output signal (a) can be generated in accordance with the frequency-dependent and/or phase-dependent transmission of the input signal (E) in the following manner: the source means (30.3) is connected to at least one filter element (30.4,30.5) such that an input signal (E) modified by the filter element (30.4,30.5) is applied to a control input of the source means (30.3) for controlling the source means (30.3) with respect to the output of an output signal (A), and an output of the source means (30.3) is connected to or corresponds with an output (30.2) of the transmission means (30).

7. Assembly (10) according to one of the preceding claims, characterized in that an input signal source (40) is connected to an input (30.1) of the transmission means (30) for providing the input signal (E) at the input (30.1), wherein the input signal source (40) has at least one drive means (50.1) for this purpose.

8. Assembly (10) according to one of the preceding claims, characterized in that the transmission means (30) are designed to perform a suppression of harmonics of the input signal (E) to at least reduce the signal emitted by the sensor electrode (20.1) in the interference frequency range.

9. Assembly (10) according to one of the preceding claims, characterized in that the source means (30.3) is electrically connected to vehicle electronics, in particular to a controller (50), to perform a switch-off of the source means (30.3) so that the assembly (10) can be switched into an energy-saving mode.

10. Assembly (10) according to one of the preceding claims, characterized in that an input signal source (40) is designed for providing the input signal (E) as follows: the input signal (E) is designed as a signal based on a rectangular signal, which is actively varied, in particular by signal shaping, preferably by smoothing of edges of the rectangular signal and/or by a variable amplitude over time, in order to assist the frequency-dependent and/or phase-dependent transmission, preferably harmonic suppression, by the transmission means (30).

11. Assembly (10) according to one of the preceding claims, characterized in that a controller (50) is provided which is electrically connected to the sensor electrode (20.1) in order to evaluate the detection of the change in the environment of the vehicle (1) by the at least one sensor electrode (20.1) in such a way that the variable Capacitance (CS) of the sensor means (20) can be evaluated by the controller (50) by means of the output signal (a).

12. Assembly (10) according to one of the preceding claims, characterized in that a control device (50) is provided for evaluating the detection of the change in the environment of the vehicle (1) by the at least one sensor electrode (20.1) in such a way that a holding means (50.4) of the control device (50) is charged in a repeatedly executed recharging phase on the basis of the variable Capacitance (CS) of the sensor means (20), so that a charge accumulation in the holding means (50.4) takes place in the recharging phase.

13. Assembly (10) according to one of the preceding claims, characterized in that the assembly (10) is adapted to be integrated in a door handle of the vehicle (1) and/or in a rear and/or side and/or front of the vehicle (1) and/or in a bumper (3) of the vehicle (1), in particular in that the sensor electrode (20.1) has an elongate extension which is adapted to the length of the door handle and/or of the bumper (3) and/or to the rear extension in the transverse direction of the vehicle.

14. Assembly (10) according to one of the preceding claims, characterized in that the transmission means (30) and/or the source means (30.3) are connected to the sensor electrode (20.1) in such a way that the electrical signal directly on the sensor electrode (20.1) and/or the signal shape of the signal corresponds at least up to 80% to the output signal (a) and/or the signal shape of the output signal (a), wherein the output signal (a) can preferably be output directly on the source means (30.3).

15. A sensor arrangement (20) for a vehicle (1), having:

-an assembly (10) according to one of the preceding claims,

-a controller (50) electrically connected to the assembly (10) to provide an input signal (E) for evaluating a variable Capacitance (CS) of the sensor mechanism (20) for the assembly (10), wherein the controller (50) is electrically connectable to vehicle electronics to activate a vehicle function depending on said evaluation.

16. An outer door handle (4) for a vehicle (1) having an assembly (10) according to one of the preceding claims.

17. Method (10) for operating a capacitive sensor system (20) of a vehicle (1), in particular for driving and/or evaluating in the capacitive sensor system (20) to detect an activation behavior at the vehicle (1), wherein the following steps are carried out:

a) An electrical input signal (E) is generated,

b) performing a frequency-dependent and/or phase-dependent transmission of the electrical input signal (E),

c) the output signal (A) is output in such a way that the guided electrical signal is output at the sensor electrode (20.1) as a function of the frequency-dependent and/or phase-dependent transmission of the input signal (E).

18. Method according to one of the preceding claims, characterized in that the assembly (10) according to one of the preceding claims can be driven.

Technical Field

The invention relates to a component of a capacitive sensor arrangement for a vehicle. The invention also relates to a sensor arrangement, an outer door handle and a method for operating a capacitive sensor arrangement of a vehicle.

Background

It is known from the prior art to use capacitive sensor arrangements with sensor elements on vehicles in order to detect changes in the sensor element environment, for example the movement or approach of a person. For evaluating the sensor element, it can be repeatedly charged and discharged, which is correspondingly accompanied by the transceiving of electrical signals within the sensor mechanism. For this purpose, periodic square signals are mostly used, which may occur due to recharging and/or due to switching between the discharge current path and the charging current path.

For evaluating the sensor element, for example, recharging methods are known, as disclosed in DE 102012102422 a1, DE 102012105266 a1, DE 102013112909 a1 or DE 102013112910 a 1.

A common problem here is that such signals for evaluation, and in particular rectangular signals, can have a frequency spectrum which contains unfavorable frequencies. It is therefore conceivable for interfering radiation to occur during the recharging of the sensor element with the signal. Accordingly, reducing the disturbing effects of the sensor mechanism on the environment is often a technical challenge and involves costly measures. Problems may arise, for example, due to interaction with radio signals in the range of 510 khz to 1.71 mhz. Such radio signals are emitted, in particular, by an external transmitter of medium-wave radio broadcasting (AM band) or the like. The measures for reducing and/or compensating the interaction are usually technically complicated and costly.

Disclosure of Invention

The object of the invention is therefore to eliminate the aforementioned disadvantages at least in part. The object of the invention is, in particular, to improve the operation of a capacitive sensor system of a vehicle.

The object is achieved by an assembly having the features of the independent device claim, a sensor arrangement having the features of the parallel device claim, an outer door handle having the features of the further parallel device claim and a method having the features of the independent method claim. Further features and details of the invention emerge from the respective dependent claims, the description and the drawings. The features and details described in connection with the inventive assembly are also obviously applicable in connection with the inventive sensor mechanism, the inventive outer door handle and the inventive method, and vice versa, so that the disclosure in connection with the various inventive aspects is always or can be mutually referred to.

This object is achieved, in particular, by a component, in particular a circuit component, of a capacitive sensor system for a vehicle, which is preferably used for driving and/or evaluating in the capacitive sensor system for detecting an activation behavior at the vehicle (for example at the front and/or the side and/or the rear of the vehicle). The activation behavior can be performed by a person in the vehicle environment, for example. Therefore, a person may wish to open the vehicle trunk lid by a posture at the rear. The gesture is, for example, a movement of a body part under the bumper, which can be detected by the sensor mechanism. A gesture within the vicinity of the vehicle door handle may also be defined as an activation action for unlocking and/or opening the vehicle door, for example.

Advantageously, the assembly of the invention has at least one of the following components:

at least one or precisely one sensor element, in particular in the form of a sensor electrode, for detecting a change in the vehicle environment, in particular in the sensor element environment, preferably in the vehicle exterior region and/or in the region below the bumper and/or in the door handle region, preferably for detecting a posture and/or an activation behavior,

a transmission means for transmitting, preferably for varying, the electrical input signal, in particular the drive signal, in dependence on frequency and/or in dependence on phase, and for outputting an (electrical) output signal, which is preferably dependent on the input signal (transmitted/varied in dependence on frequency and/or in dependence on phase) and which is preferably designed to force the transmitted sensor voltage and/or the forced transmitted sensor current,

an output of the transmission means, which is directly or indirectly electrically connected to the sensor element or sensor electrode, for outputting the output signal at the sensor element or sensor electrode,

-an input of the transmission means, where the input signal is provided.

In this case, it is provided in particular that the transmission means have a controlled source means for generating the output signal as a function of the frequency-dependent and/or phase-dependent transmission of the input signal, preferably as a function of the frequency and/or phase change (i.e. in particular controlled by the transmitted/changed input signal), and preferably as a guided electrical signal at the sensor electrode. This has the advantage that the frequency spectrum of the input signal can be adjusted by the transmission means, i.e. that (undesired) interfering frequencies of the input signal can be filtered out and/or avoided when outputting the output signal at the sensor electrode, for example. However, it is also possible to ensure very reliably by using the source means that the signal applied to the sensor electrodes also has a frequency spectrum (substantially, for example, within predetermined tolerances) that has been adjusted by the transmission means. The solution according to the invention is based in particular on the design that the use of a rectangular signal as output signal for the sensor electrodes is problematic with regard to potentially disturbing frequencies, and that passive filtering of the input signal is not particularly sufficient, since disturbing frequencies may occur when the output signal is transmitted to the sensor electrodes. In particular, it is not sufficiently ensured that: the transmission of the output signal and/or the output at the sensor electrode does not have an interfering influence on the output signal and/or the electromagnetic radiation at the sensor electrode. A particular advantage is thus obtained in that a controlled source mechanism is utilized to provide a guided signal at the sensor electrodes. In particular, the output signal output is advantageous for reducing interference, in that signal guidance at the sensor electrode can be achieved by actively generating the output signal, as a result of which the problem of the frequency of the radiated interference at the output signal of the sensor electrode can be dealt with very reliably.

Advantageously, only a single (structurally provided) sensor electrode can be provided in the assembly of the invention for forming the (variable) sensor capacitance, wherein the counter electrode is preferably formed by the vehicle ground to form the sensor capacitance and is therefore not considered as a separate (dedicated) component. Preferably, the parasitic capacitance of the sensor means is negligible in this case. This allows a particularly simple structural design.

The sensor electrodes may be sensor elements composed of an electrically conductive material. For example, the sensor electrodes are designed as long-strip-shaped (elongated) electrical conductors, for example in the form of cables, and are optionally connected to the vehicle electronics only by a single direct electrical connection.

In this case, an electrical connection can be understood to mean not only a direct connection but also an indirect connection, i.e. also via further electrical components, but preferably only if the connection is made only electrically. For example, the electric field between the sensor electrode and the vehicle ground cannot be regarded as a direct electrical connection, so that the sensor electrode preferably has only one direct electrical connection to the vehicle electronics. Optionally, vehicle electronics may also refer to at least the sensor device and/or the controller and/or the transmission device.

The vehicle is preferably designed as a motor vehicle, preferably as a passenger car and/or an electric vehicle and/or as a hybrid vehicle and/or as an autonomous vehicle.

It is also conceivable for the at least one sensor element, preferably the at least one sensor electrode, to be arranged in the front and/or in the side and/or in the rear of the vehicle, in order in particular to detect changes in the environment and/or corresponding activation actions in the peripheral region, i.e. in the front and/or in the side and/or in the rear of the vehicle. In this way, the activation behavior in the peripheral region can be reliably detected by the sensor arrangement. For example, vehicle components and/or functions in this peripheral region can be moved or activated intuitively as a function of the detection. Such functions are, for example, the lighting of the vehicle and/or the unlocking of the vehicle locks and/or the like. This component can be designed, for example, as a trunk lid and/or a side door and/or a sliding door and/or a hood, which is moved and/or opened and/or closed in dependence on the detection. It is also optionally possible for the sensor element to be arranged at and/or in the region of a door sill in order to open a side door or a sliding door of the vehicle, for example, as a function of the detection. In order to be able to reliably detect the movement and/or the movement pattern as a function of the detection, at least two sensor elements, preferably sensor electrodes, may also be provided as an alternative or in addition to the aforementioned features. They are for example arranged jointly in at least one of the aforementioned peripheral regions, for example in the bumper or in the door sill or door handle or the like.

The controlled source mechanism, in particular the current source mechanism and/or the voltage source mechanism, may refer to a real electrical element or circuit, which functions as an approximation to an ideal controlled source (i.e. a "dependent source"), in particular an ideal controlled current source and/or voltage source. The source mechanism can therefore be understood as a real controlled source, in particular a real current source or a real voltage source (CVS). Such a source mechanism is, for example, an operational amplifier (OP), in particular a controlled, preferably voltage-controlled OP amp. It is particularly advantageous that the source mechanism is designed as a (true) low-resistance controlled (voltage) source. The source means can be designed to be low-resistive, for example, in such a way that the internal resistance (output resistance) and/or the input resistance of the source means are designed to be low-resistive, preferably always less than 1 kiloohm or less than 500 ohms or less than or equal to 100 ohms, wherein the internal resistance and the input resistance can also have different values. For this purpose, the reaction of the downstream circuit to the source mechanism is significantly reduced, so that the behavior of the output signal and in particular also the signal applied to the sensor electrodes can be determined very precisely. In other words, the output signal can be output as a guided signal, i.e. in particular the signal is actively generated by the source mechanism and/or the signal profile at the sensor electrode is actively controlled (i.e. guided or regulated). The source means is advantageously designed to produce a coupling between the control input and the output of the source means that is as reaction-free as possible. At the source mechanism, at the output of the source mechanism, a signal (e.g. a current or a voltage) may be controlled, in particular by a control signal (control current or control voltage) at the control input of the source mechanism. According to the invention, additional steps and expenditure for integrating the source mechanism are tolerable, in order to advantageously obtain an improved and reliably controllable signal output at the sensor electrode by comparatively simple circuit-technical measures.

It is also advantageous if the source mechanism is designed as a true low-resistance controlled current source and/or voltage source in order to output the generated output signal as a directed electrical signal, preferably at the sensor electrode. This has the advantage that the influence occurring between the transmission means and the sensor electrode has only a weak influence on the signal.

In a further possible embodiment, it can be provided that the source means is designed as an active element, preferably as an operational amplifier, wherein the source means is preferably connected (in particular directly) to a (separate) supply voltage in order to preferably actively generate the output signal and in particular to actively load the output signal via the output at the sensor electrode. In other words, the output of the output signal can be effected by the source means in order to apply the output signal to the sensor electrode, wherein the output signal is actively generated by means of the supply voltage. Thereby, it is possible to reduce the deviation of the signal shape when the signal is applied.

Furthermore, it is possible in the assembly according to the invention that the assembly and/or the transmission means and/or the filter element are dimensioned such that at least (-)20dB, in particular (-)30dB, harmonic suppression is performed, preferably from the second or third harmonic. In other words, attenuation may be achieved from the second or third harmonic, where the signal is attenuated from the second or third harmonic (e.g., by at least 20 dB). This results in the output signal being attenuated by at least 20dB compared to the input signal with respect to the frequency corresponding to the second or third harmonic.

Preferably, it can be provided that the transmission means have at least one filter element for forming an electronic filter, preferably an all-pass filter and/or a low-pass filter and/or a band-pass filter, for carrying out a frequency-dependent and/or phase-dependent transmission, preferably a frequency-dependent and/or phase-dependent change, of the input signal. Simple measures can be provided for this purpose to suppress interfering frequencies. The source mechanism is preferably connected to at least one of the at least one filter element, thereby forming an active filter, particularly preferably a Sallen-Key filter. The active filter can be formed, for example, such that an operational amplifier is used as the source mechanism. This results in particular in a signal guidance.

It is also possible within the scope of the invention to provide that the transmission means have a first filter element, in particular for forming an RC low-pass filter, preferably a first-order filter, and/or a second filter element, in particular for forming a Sallen-Key filter, preferably a second-order filter. Optionally, the filter elements can be connected to each other to jointly perform a frequency-dependent and/or phase-dependent transmission of the input signal, preferably a frequency-dependent and/or phase-dependent change and/or to increase the filter order of the transmission means. It is also conceivable to provide further filter elements which are connected to one another, for example, in order to further increase the filter order of the transmission means. In particular, the filter element can have only passive components to reduce the cost and/or the structural expenditure.

According to a further advantage, it can be provided that the output signal can be generated as a function of the frequency-dependent and/or phase-dependent transmission of the input signal, preferably as a function of the frequency and/or phase, in the following manner: the source means is connected to at least one filter element, whereby the input signal transmitted/modified by the filter element is preferably applied to a control input of the source means for controlling the source means with respect to the output of the output signal, preferably by connecting the output of the source means to the output of the transmission means, or in correspondence therewith. In other words, the transport mechanism may have two regions: i.e. an input area with at least one filter element via which an input signal is transmitted or changed (i.e. filtered) in dependence on frequency and/or in dependence on phase, and an output area with said active means, which can provide an output signal directly at the output of the transmission means and which is connected to the filter element, in particular via a control input. This has the advantage that the output signal can be generated as a directed signal by the source mechanism under the control of the input signal.

In a further possible embodiment, it can be provided that an input signal source (for example, electrically or optically and/or galvanically isolated) is connected to the input of the transmission means in order to provide the input signal preferably at the input, wherein the input signal source preferably has at least one drive means, in particular with a digital-analog converter and/or a microcontroller, for this purpose. For example, the software of the microcontroller may directly generate the input signal (and output it, for example, by a digital-to-analog converter), so perhaps also perform further signal shaping of the input signal. It is also conceivable that the drive mechanism is designed for driving an electronic switching element or the like to generate an input signal in the form of a rectangular signal. Thus, a simple signal generation may be achieved for evaluating the sensor electrode.

According to another possibility, it can be provided that the transmission means are designed to perform a suppression of input signal harmonics, in order to preferably at least reduce the signal emitted by the sensor electrodes in the interference frequency range. Here, the emission means, in particular, that the sensor electrode emits an electromagnetic wave as a function of the output signal. In other words, the frequency-dependent and/or phase-dependent transmission, preferably a change in frequency and/or phase, effected by the transmission means can influence the frequency range from which the transmission originates. For this purpose, the emission can be controlled in order to reliably comply with, for example, limit values.

It is optionally conceivable for the source mechanism to be electrically connected to the vehicle electronics, in particular to a control unit, in order to preferably perform a switch-off of the source mechanism, so that the assembly can be switched into the energy-saving mode. The switch-off can be triggered, for example, in such a way that a certain time has elapsed during which no activity (for example, no activation action) has taken place. The use of a source mechanism has the advantage that it can be switched off in a simple manner, which in turn can contribute to a reduction in energy consumption.

It is also conceivable to design the input signal source for providing the input signal as follows: the input signal is designed as a signal based on a rectangular signal, which is actively varied, in particular by signal shaping, for example by smoothing of edges of the rectangular signal and/or by time-varying amplitude, in order to preferably assist the transmission and/or variation, preferably harmonic suppression, by the transmission means in terms of frequency and/or in terms of phase. In other words, prior to the transmission or change by the transmission means as a function of frequency and/or as a function of phase, signal shaping is carried out beforehand to improve the change by the transmission means. In this case, it has proven to be particularly advantageous if the input signal is generated by means of a signal shaping having a step shape and is combined with a "smoothing" in the sense of a time-dependent amplitude. This signal shaping shall be referred to simply as "sinusoidal step shape". In accordance with the input signal thus shaped, an output signal which is as sinusoidal as possible can be generated very reliably by the transmission means and which therefore has a small frequency bandwidth and accordingly only a few interfering frequencies outside the operating frequency.

Smoothing means, in particular, that the amplitude is caused to vary over time and/or the slew rate of the input signal is reduced, for example by low-pass filtering or by corresponding operation of the drive means and/or digital-to-analog converter and/or the like.

Preferably, it is provided that the frequency-dependent and/or phase-dependent transmission and/or change is a harmonic suppression, in particular from the second or third harmonic of the input signal. Alternatively or additionally, it can be provided that the frequency-dependent and/or phase-dependent transmission and/or variation is designed to be transmitted in the sense of an all-pass filter, i.e. for example with an equivalent frequency characteristic that is (substantially) constant for all (fundamental) input signal frequencies, while the phase shift is possibly frequency-dependent. The transmission means may provide an output signal, for example also in the form of a rectangular signal or the like. It is also conceivable that the transmission mechanism is designed as a wire or the like, so that the input signal (with respect to the signal shape) is transmitted substantially unchanged and is output as an output signal, for example in the form of a signal based on a rectangular signal. Accordingly, the frequency-dependent and/or phase-dependent transmission and/or change may have a constant equivalent frequency characteristic and/or phase variation. Alternatively, the transmission mechanism may have a non-constant equivalent frequency characteristic and/or phase variation. It is particularly advantageous here to provide the output signal as a sinusoidal signal, which can be achieved, for example, by a frequency-dependent input signal change in the case of low-pass and/or band-pass filtering, in particular for harmonic suppression.

The use of a controlled source mechanism can lead to significant advantages not only when rectangular signals are used as output signals, but also when sinusoidal signals are used, and also when other desired signal forms are used. It is thereby ensured that the output signal always has the desired signal shape at the sensor electrode. The inventive assembly can therefore be used in principle for all conceivable signal types or signal shapes of input signals and/or output signals, and is claimed here.

In a further possible embodiment, a control unit can be provided which is electrically connected to the sensor electrodes in order to evaluate the detection of a change in the vehicle environment by at least one sensor electrode, preferably in such a way that the variable capacitance of the sensor arrangement, which variable capacitance is associated with the sensor electrodes and the environment, can be evaluated by the control unit using the output signal, wherein the electrical connection is particularly preferably such that the charge of the sensor electrodes can be transferred to the control unit for determining the variable capacitance. For this purpose, the output signal can be used, for example, for charging the variable capacitance in the transmission phase and preferably for charging the holding means in dependence on the variable capacitance in the recharging phase. The change in capacitance of the sensor means is then evaluated by charging the holding means, whereby the activation behavior may be detected by the controller.

According to another possibility, a control unit can be provided for evaluating the detection of a change in the vehicle environment by at least one sensor electrode in such a way that the holding means of the control unit is charged in a repeatedly executed recharging phase as a function of the variable capacitance of the sensor means, so that preferably a charge accumulation at the holding means takes place in the recharging phase, for which purpose the sensor electrodes are electrically connected to the holding means, in particular in the respective recharging phase. The input signal can preferably also be generated and/or shaped by the controller and supplied to the transmission means at the input.

It is also conceivable to provide an electronic switching element which is actuated by the control unit in such a way that it repeatedly connects the at least one sensor electrode alternately to the receiving path and to the transmitting path. In this case, the receiving path can lead to the holding means for carrying out the recharging phase, while the transmitting path leads to the transmitting means for carrying out the transmitting phase.

It is also possible within the scope of the invention for the assembly to be suitable for integration into a vehicle door handle and/or into the rear and/or side and/or front of a vehicle and/or into a bumper of a vehicle, in particular for the sensor electrode to have an elongate extension which is adapted to the length of the door handle and/or of the bumper and/or to the rear extension in the transverse direction of the vehicle. It may be possible in this case for the sensor electrodes to be designed as wires having a length which corresponds to at least 50% or at least 80% of the length of the door handle or bumper. Thus allowing a wide detection range. At least one sensor electrode in the bumper can be used as a so-called kick sensor, so that the invention is also directed to a kick sensor having the inventive sensor arrangement. It is also conceivable that the sensor electrode has an extension shape different from the elongated extension shape, for example substantially circular or rectangular or point-like, etc.

It is also conceivable within the scope of the invention for the transmission means and/or the source means to be connected to the sensor electrode in such a way that the electrical signal directly at the sensor electrode and/or the signal shape of the signal corresponds at least up to 80% to the output signal and/or the signal shape of the output signal, wherein the output signal is preferably directly outputable at the source means. Thereby it can be ensured that the interference frequency is reliably reduced.

The subject of the invention is also a sensor arrangement for a vehicle, having:

-a component, in particular a component of the invention,

a controller electrically connected to the assembly to provide an input signal to evaluate a variable capacitance of a sensor mechanism for the assembly. In this case, provision can be made for the controller to be electrically connected to the vehicle electronics in order to activate a vehicle function as a function of the evaluation (such as, for example, authentication by means of an identification device and/or unlocking and/or opening of a trunk lid and/or a door of the vehicle). For example, the verification may be initiated if the activation behavior is successfully detected, in order to cause opening and/or unlocking if the verification is successful. The sensor arrangement according to the invention thus offers the same advantages as those explicitly described in relation to the components according to the invention.

An exterior door handle for a vehicle having the assembly of the present invention is also claimed.

The subject matter of the invention is also a method for operating a capacitive sensor system of a vehicle, in particular for driving and/or evaluating in the capacitive sensor system in order to detect an activation behavior at the vehicle, for example at the front and/or the side and/or the rear of the vehicle.

Advantageously, in the method according to the invention, at least one of the following steps can be carried out, wherein the steps can preferably be carried out in the described order or one after the other in any order, and wherein individual steps may possibly also be repeated:

a) an electrical input signal is generated which is,

b) a frequency-dependent and/or phase-dependent transmission and/or variation of the electrical input signal is performed,

c) the output signal is output in such a way that the guided electrical signal is output at the sensor electrode as a function of the frequency-dependent and/or phase-dependent transmission and/or change of the input signal, in particular by controlling the source mechanism as a function of the transmitted and/or changed electrical input signal and generating the output signal and/or outputting it at the sensor electrode as a function of said control.

To this end, the method of the invention brings the same advantages as explicitly described with respect to the components of the invention. In addition, the method can be adapted to drive the assembly of the invention.

Drawings

Further advantages, features and details of the invention emerge from the following description of an embodiment of the invention with reference to the drawing. The features mentioned in the claims and the description may be of importance for the invention here in each case individually or in any combination, where:

figure 1 shows a perspective view of the rear of a vehicle with a user,

figure 2 shows a schematic circuit diagram of a sensor mechanism,

figure 3 shows a schematic view of an assembly of the invention,

figure 4 shows a schematic view of a sensor mechanism,

figure 5 shows a schematic diagram of a signal profile,

figure 6 shows another schematic of the assembly of the present invention.

Detailed Description

In the following figures, the same reference numerals are used for the same features even in different embodiments.

Fig. 1 schematically shows a perspective view of a vehicle 1. A trunk lid 2 is shown above a bumper 3 of the vehicle 1, wherein the trunk lid 2 can be opened, for example, according to a (first) vehicle function and/or can be closed again according to a (second) vehicle function. At least one sensor element 20.1, in particular a sensor electrode 20.1, of the capacitive sensor system 20 can be incorporated into the bumper 3. Alternatively or additionally, the at least one sensor element 20.1 may also be integrated into the (outer) door handle 4 of the vehicle 1 or other vehicle components. The capacitive sensor system 20 accordingly has a capacitive sensor, which is formed at least in part by the sensor element 20.1. The sensor element 20.1 is preferably designed in the form of a cable and/or has an elongated extension in order to provide the widest possible detection range for detecting the activation behavior. It is also conceivable that the sensor element 20.1 has an extension shape different from the elongated extension shape, for example substantially circular or rectangular or point-like, etc. The activation behavior is, for example, a movement of an activation medium 9 of the user 8, such as a body part 9, in particular a foot 9, in an environment outside the vehicle 1 or the sensor element 20.1. To perform the activation action, the user 8 can move the activation medium 9 under the bumper 3. This movement is then detected by a change in the sensor capacitance CS of the capacitive sensor arrangement 20 and can preferably be evaluated and detected by the controller 50 of the sensor arrangement 20. For this purpose, the controller 50 is electrically connected and/or wired to the sensor element 20.1. Accordingly, it may be expedient for the controller 50 to be designed as a control device of the vehicle 1, preferably as part of the vehicle electronics or electrically connected thereto. In this case, it is conceivable that, in order to reduce the circuit costs, only a single electrical connection, for example a single electrical line such as a cable, is routed from the controller 50 to the sensor element 20.1, i.e. it is connected only by a single electrically conductive connection. The sensor element 20 is thus a sensor electrode 20.1 for providing a sensor capacitance CS. It is also possible that the detection of the activation behavior is performed by the controller 50, the controller 50 then activating the vehicle function or at least one of the vehicle functions.

The detection principle for detecting the activation behavior and evaluating the sensor capacitance CS is illustrated in detail in fig. 2 in a schematic circuit diagram of the capacitive sensor system 20 and of the assembly 10 according to the invention, in particular of the circuit assembly 10. Only one sensor element 20.1 can be provided or perhaps a plurality of sensor elements 20.1 can also be provided. Fig. 2, for example, shows two sensor elements 20.1 in the form of sensor electrodes 20.1, each of which can provide a sensor capacitance CS. In other words, the respective sensor element 20.1 or the sensor electrode 20.1 can provide a respective capacitive sensor, which can be understood as a capacitor, respectively. In the case of a plurality of sensor elements 20.1, at least one switching mechanism 60 with at least one selective switch can be provided, by means of which the sensor elements 20.1 are selected in turn, i.e. an electrical connection is established therewith. The at least one switching means 60 in this case connects the sensor elements 20.1, for example, alternately to the prefilter assembly 80 and/or to the at least one switching element S. The use of at least two sensor elements 20.1 has the advantage that, for example, a movement and/or a movement pattern can be detected.

The respective sensor element 20.1 can have an electrically conductive material for forming the (unique) sensor electrode 20.1, respectively. At this point, it is sufficient to provide the sensor capacitance CS only with the respective sensor electrode 20.1 without a counter electrode. In this case, the counter electrode (with respect to the respective sensor element 20.1) as shown in fig. 2 is merely schematic for illustrating the principle and should not be regarded as an actual component. Alternatively, at least one counter electrode or a corresponding counter electrode for each sensor element 20.1 can also be provided in the structure.

Each sensor element 20.1 can form a sensor capacitance CS with respect to a ground potential 20.2, in particular the vehicle ground, and with respect to the vehicle 1 environment. The sensor capacitance CS can thus change as a result of the surroundings of the vehicle 1, i.e. in particular when the activation medium 9 moves into the peripheral region of the sensor element 20.1. In this way, the activation behavior can be sensed very reliably from the sensor capacitance CS.

Various different methods are contemplated for evaluating the sensor capacitance CS. The method is based in particular on the fact that the charge located in the sensor element 20.1 or stored by means of the sensor capacitance CS can be transferred to the holding means 50.4 with the holding capacitance CH. The fact that the charge stored is dependent on the variable sensor capacitance CS and thus on the environment of the vehicle 1 (e.g. the activation behavior) is used in this case. The holding means 50.4 may in this case have holding capacitors for charge storage and/or charge temporary storage and for charge evaluation by the controller 50. Advantageously, the holding means 50.4 has an operational amplifier OP' which forms an integrator (see also fig. 6 for this purpose) optionally with at least one further element and/or a feedback element (optionally designed phase-dependent and/or frequency-dependent), for example by means of a capacitor. The integrator is then used to store an amount of charge, which is specific to the amount of charge received by the sensor element 20.1 via the received signal when recharging. The operational amplifier OP' may be connected via an output O, perhaps via an analog-to-digital converter 50.2, to a drive mechanism 50.1, for example in the form of a microcontroller, in order to evaluate the amount of stored charge.

For recharging, preferably a repeatedly performed receiving phase (also called recharging phase) can be used. The receiving phase may be a certain switching phase, i.e. the switching state of the at least one switching element S. For this purpose, for example, the at least one switching element S, in particular the at least one changeover switch S, is repeatedly switched, preferably at a frequency of 333 khz. In this case, the receiving phase is entered when the switching element S electrically connects the receiving path r to the sensor element 20.1. After the switching element S has been switched further to the other switching state, a transmission phase (also referred to as charging phase, for example) is entered, in which the switching element S electrically connects the transmission path t to the sensor element 20.1. The two paths r and t can be designed here as wires (for example on a printed circuit board), which thus provide an electrically conductive connection.

This transfer phase can be used to supply the sensor element 20.1 with charge, i.e. to cause charging of the capacitive sensor. In this case, the sensor element 20.1 is electrically connected to the transmission means 30, for example, in the transmission phase via the switching element S and via the transmission path t. This results in the transmission of the output signal a via the transmission path t, in particular from the transmission means 30 to the sensor element 20.1. While the receiving phase can be used to receive the charge located therein (as accumulated due to the sensor capacitance CS), i.e. cause a recharge, from the sensor element 20.1. In this case, the sensor element 20.1 is electrically connected to the holding means 50.4, for example in the receiving phase, via the switching element S and via the receiving path r. This results in a transmission of the reception signal via the reception path r, in particular from the sensor element 20.1 to the holding means 50.4. In addition, it is also possible to switch the switching mechanism 60 repeatedly in order to connect different sensor elements 20.1 alternately to the reception path and to the transmission path r, t.

In the following, the receiving phase is explored in detail, which can be used for evaluation in the sensor mechanism 20. In the receiving phase, the charge stored by means of the sensor capacitance CS can be "transferred", i.e. the holding means 50.4 with the holding capacitance CH (e.g. the holding capacitor) can be charged in dependence on the sensor capacitance CS or the charge stored thereby (e.g. in proportion thereto). In this case, recharging may take place via the low-pass filter 50.5 and/or, for example, also via a current mirror, which is not explicitly shown. The charge state of the holding means 50.4 or of the holding capacitor, which is then relevant for the detection of the activation behavior, can be determined, in particular, by the analog-digital converter 50.2, depending on the voltage via the holding capacitor or in series to the holding capacitor. For this purpose, the analog-to-digital converter 50.2 can be connected, for example, via a low-pass filter 50.5 to the holding means 50.4 on the one hand and to the drive means 50.1 on the other hand. In addition, at least one further control element 50.7 (also referred to as compensator) can optionally also be connected to the reception path r, in order to, for example, perform compensation for charge excesses during recharging. For this purpose, the control element 50.7 may comprise, for example, a regulating circuit. Thus, the control element 50.7 (possibly together with other components such as the drive mechanism 50.1) may be designed to detect an excess of charge (i.e. when the amount of transferred charge can no longer be stored by the holding capacitor CH) and/or to perform a compensation.

The drive 50.1 of the control unit 50 can be designed, for example, as a microcontroller or the like and can also (in particular repeatedly and/or periodically) switch the switching element S. The drive means 50.1 can in particular execute the switchover as a function of the at least one adjusting means 50.3, preferably a computer program, in order to determine and/or vary the phase duration of the receiving phase and/or of the transmission phase accordingly. In addition, the alternating execution of the receiving phase and/or the transmission phase can also be interrupted by the drive 50.1, i.e. a further interruption phase is introduced. For example, to suspend outputting the output signal a and/or to suspend transmitting the received signal, for example, in order to reduce power consumption.

The circuit diagram according to fig. 2 clearly shows that, in particular, the switching element S switches without further measures to generate a square-wave signal for driving and/or evaluating the sensor element 20.1. Which accordingly has a very wide frequency spectrum. Without further measures, this unfavorable spectrum may lead to: the sensor element 20.1 causes interfering electromagnetic radiation (emissions) in the vehicle 1 environment, and in particular in frequency ranges which may have an interfering effect on other radio signals or the like.

It can therefore be provided as a measure within the scope of the invention that a phase-dependent and/or frequency-dependent transmission and/or modification of the at least one signal is carried out for the purpose of driving and/or evaluation. For example, for driving (i.e. for transmission to the sensor element 20.1 and/or for charging and/or driving the sensor element 20.1), a signal, i.e. an output signal a, can be output and/or generated directly at the output 30.2 of the transmission means 30, wherein the signal spectrum width, in particular harmonics and thus interference effects, can be reduced by signal shaping and/or filtering. As a further signal, the reception signal of the sensor element 20.1 can also be influenced for evaluation by the phase-dependent and/or frequency-dependent transmission or change, for example by connecting the transmission means 30 to the holding means 50.4, in order to thereby control the reception of the reception signal.

It is also advantageous that the signal and/or the signal shaping is influenced by the drive mechanism 50.1 and/or a drive assembly 50.6 connected to the drive mechanism 50.1 and/or integrated therein. Which can be connected to an input 30.1 of the transmission means 30 for supplying an input signal E, in particular a drive signal E, to the transmission means 30 at the input 30.1. In this way, the transmission means 30 can be connected between the drive means 50.1 and the sensor element 20.1 in order to carry out a frequency-dependent and/or phase-dependent transmission or variation of the input signal E. This is particularly advantageous as a frequency filtering in that interfering frequencies in the input signal E are largely filtered out. For this purpose, input signal E can be filtered when applied to input 30.1 of transmission means 30 and output as output signal a at output 30.2. The guided output signal a can also be output by the transmission means 30 as a function of the transmitted/modified (in particular filtered) input signal E. This ensures that the shape of the transmitted or modified or filtered signal and thus the filtered frequency spectrum are also maintained at the sensor element 20.1. By "guided" can be meant, in particular, that the output signal a is actively generated as a function of the transmitted or modified or filtered input signal E and is applied to the sensor element 20.1, for example by using an operational amplifier OP.

As can be seen schematically from fig. 2 and further in particular also from fig. 6, the transmission means 30 can also be connected to the input of the holding means 50.4. The holding means 50.4 here comprise, for example, an integrator. For example, it can be provided that the input of the transmission means 30, in particular the non-inverting input "+" of the operational amplifier OP of the transmission means 30, is connected to the input of an integrator, preferably to the (non-inverting) input "+" of a further operational amplifier OP' of the integrator. Preferably, the connection is designed to allow the holding means 50.4 to receive the reception signal from the sensor element 20.1 via the reception path r as a function of the frequency-dependent and/or phase-dependent transmission and/or change caused by the transmission means 30. For this purpose, the signal provided by the transmission means 30, which has a frequency-dependent and/or phase-dependent change as a result of the filtering (for example at the "+" input of the operational amplifier OP in fig. 3 and 6), for example, influences the function of the holding means 50.4 or of the integrator. When connected to the integrator input, the provided signal may be understood as an integration reference (e.g. due to being connected to the non-inverting operational amplifier input of the integrator, the provided signal affects the differential voltage of another operational amplifier OP 'of the integrator and may also affect the received signal by feedback in the operational amplifier OP'). The connection of the elements shown in fig. 6 corresponds here to the connection in fig. 2 and 3, as indicated by the connecting dashed lines.

The transport mechanism 30 is shown in more detail in fig. 3. The circuit for generating the input signal E, i.e. in particular the controller 50, preferably the drive mechanism 50.1 and/or the drive assembly 50.6, is schematically represented by the input signal source 40. Which is capable of generating an electrical input signal E such as at least one input signal E substantially in the form of a rectangular signal or based thereon. The drive element 50.6 may possibly also perform further signal shaping of the input signal E, for example by means of a switchable resistor, in order to shape the input signal E. For this purpose, the drive assembly 50.6 can also be controlled by the drive mechanism 50.1, in order to perform signal shaping, for example, under the control of the adjustment mechanism 50.3. The input 30.1 is electrically connected to at least one first filter element 30.4 (in particular an RC circuit) and/or a second filter element 30.5 (in particular a further resistor R and/or a capacitor C) to form a Sallen-Key filter. The first filter element 30.4 comprises for example a (possibly only) resistor R and a (possibly only) capacitor C. Preferably, a third order filter can be provided by the transmission mechanism 30 as a whole by connecting the two filter elements 30.4, 30.5. The use of an operational amplifier OP also allows to construct an active filter, preferably a Sallen-Key filter.

In fig. 2, the drive mechanism 50.1 is schematically connected to the drive assembly 50.6 by wires. This may simply show a circuit diagram, which may also be understood here as a plurality of lines, which connect the respective outputs of the drive 50.1 to the respective resistors of the drive assembly 50.6. The drive mechanism 50.1 can thus be connected to the drive assembly 50.6, for example, by at least one or two or three or four individual lines, in particular in order to control at least one resistor of the drive assembly 50.6 in each case by means of a line. In addition, a line can, for example, connect the respective output of the drive 50.1 to at least one resistor of the drive assembly 50.6, respectively, and preferably then electrically connect the respective output to the input 30.1 via the respective resistor/resistors. For example, the drive assembly 50.6 comprises at least two or three or four resistors, which are connected to the drive mechanism 50.1 via respective leads with a first terminal and to the input 30.1 with a second terminal, respectively. In this case, it is a different conductor and output of the drive mechanism 50.1, the resistors can be driven individually and/or independently of each other to provide the shaped input signal E at the input 30.1. In other words, a programmable voltage divider is formed by the drive assembly 50.6. It allows shaping of the input signal E, as detailed in relation to fig. 5.

It can be seen that the filter elements 30.4, 30.5 can be electrically connected to the source means 30.3, in particular the current source means and/or the voltage source means 30.3. In the example shown in fig. 3, the source means 30.3 are designed as operational amplifiers OP, which are connected to the filter elements 30.4, 30.5 in the sense of a Sallen-Key filter configuration. Accordingly, the operational amplifier OP and/or the source means 30.3 may also be referred to as another filter element. The source means 30.3 cause an output signal a to be output at an output 30.2 in dependence on the input signal E filtered by the filter elements 30.4, 30.5. For the active transmission of the output signal a, the source means 30.3 are connected to a supply voltage. For example, a first voltage U1 for providing a first supply potential VE and a second voltage U2 for providing a second supply potential VC are shown, wherein the voltages are, for example, of equal value but of different polarity. U1 is, for example, -5V and U2 is, for example, + 5V. By appropriate design of the components, a transmission means 30 can be provided which has the filter properties of an active low-pass filter, in particular third-order and/or attenuates by-20 dB at 1 mhz and/or has a limit frequency of 470 khz. In other words, at least-20 dB of harmonic rejection may be provided. The filter is particularly suitable for sensor means 20 operating frequencies of (essentially) up to 333 khz, which are determined by the switching frequency between the receiving phase and/or the transmission phase. For example, the operating frequency (or also other operating frequencies) is thus determined by or corresponds to the switching frequency of the switching element S. In particular, harmonics can be effectively suppressed from the second harmonic or the third harmonic.

Alternatively, it is also possible to dispense with the filter elements 30.4, 30.5, so that the transmission means 30 have, for example, only the controlled source means 30, in order to transmit the input signal E substantially unchanged and then to output it as the output signal a (for example in the form of a rectangular signal) unfiltered. The transmission mechanism 30 may have filter performance such as all-pass filtering.

Another alternative and/or supplement to the assembly 10 of the present invention is shown in phantom in fig. 3. In this case, a connection to a further source 30.3 'can be provided at the output 30.2, preferably at the operational amplifier OP and/or the source 30.3 and/or at least one filter element 30.4, 30.5, in order to provide an alternative output 30.2'. This design is only optional here, in order to use, for example, current sources and/or converters as further source means 30.3 'in order to thus output the guided output signal a' in an alternative manner. In addition to the illustrated design with operational amplifier OP, a design with another source mechanism 30.3' may be used, or may also be used instead of source mechanism 30.3. In the latter case, the filter formed by the filter elements 30.4, 30.5 can also be designed as a passive filter and/or the further source means 30.3' can also be designed as a filter element to form an active filter. In principle, the output signal a or a' can thus be a forced sensor voltage or a forced sensor current.

Fig. 4 shows the transmission path of the signal S' between the switching element S and the at least one sensor element 20.1. Within this transmission route, further electronic components can also be arranged along the transmission path u, which is indicated by the dashed line of the transmission path u. Other elements may for example cause further filtering of the signal S'. The switching element S connects the transmission path to the reception path r for evaluation or to the transmission path t for driving according to the switch position (switching state). In the first switching position of the switching element S, the signal S' can therefore correspond to the output signal a, which is transmitted from the output 30.2 of the transmission means 30 to the sensor element 20.1. In a second switching position of the switching element S, the signal S' can correspond to the reception signal and be transmitted to the holding means 50.4 via the reception path r. In the latter case, the signal S is dedicated to said detection and may be evaluated, for example, by the controller 50 to detect the activation behavior.

As also shown in fig. 4, a pre-filtering assembly 80, preferably in the form of a notch circuit and/or a band pass filter or band stop filter (band stop filter arrangement), and in particular a pre-selector 80, may be employed. This allows the interference frequencies of the signal S' that may occur due to the sensor element 20.1 (in the incident or intrusion sense) to be filtered out. From this it is clear that: the sensor element 20.1 can also be designed as an antenna, via which radiation emission (from the sensor unit 20 to the surroundings of the vehicle 1) and radiation intrusion (from the surroundings to the sensor unit 20) can take place. The expressions "transmission" and "intrusion" are used in this case in the sense of interfering radio signals or electromagnetic radiation. The pre-filtering assembly 80 may be designed, for example, as an LC tank circuit and/or a trap circuit, for example, comprising a capacitor C and a coil L connected in parallel with each other. The pre-filter assembly 80 is for example connected to first and second terminals 80.1, 80.2. Advantageously, the first terminal 80.1 may connect the pre-filter assembly 80 to a supply potential and/or the second terminal 80.2 may connect the pre-filter assembly 80 to a ground potential. This has the advantage that signal components of the signal S' in undesired frequency ranges can be conducted, i.e. led away, through at least one of the terminals. For this reason, the pre-filtering assembly 80 is low impedance for the frequency range that may be undesirable. While for the desired frequency, the pre-filtering component 80 may be high-impedance, so for this frequency the signal S' is not conducted through the pre-filtering component 80 (the pre-filtering component 80 thus acts as a band-pass filter for the desired frequency in such a way that the pre-filtering component 80 does not drain away the desired frequency). In the ideal case, i.e. when driven only with a signal S' having the desired frequency, no losses due to filtering occur. The power loss can be correspondingly significantly reduced by the structure. It is also possible to add a resistor and/or a resistor component for the pre-filtering component 80 in the receiving path r and in the transmitting path t, respectively, which resistor and/or resistor component is preferably designed to be (substantially) identical (with the same resistance value and/or the same size and/or the same impedance). The resistors and/or resistor assemblies may be designed to adjust the transmission function of the pre-filter assembly 80.

Fig. 5 shows different possibilities II to V for signal shaping of the input signal E (solid line) and the output signal a (dashed line) resulting therefrom, respectively. For the purpose of illustration, a diagram I is shown, in which no frequency-dependent and/or phase-dependent change of the input signal E and/or only a frequency-dependent and/or phase-dependent transmission of the input signal E takes place by means of the transmission means 30. In contrast, in the illustration II, the filtering of the input signal E is carried out by the transmission means 30, i.e. in particular by means of a filter element. The filter element here preferably provides an analog low-pass filter, which changes the rectangular shape of the input signal E. In this way a sinusoidal output signal a can be provided. Fig. III shows an example of further signal shaping, in which, in addition to filtering by means of the filter elements of the transmission means 30, modulation (in particular as "smoothing") is also caused by the drive means 50.1 and/or the drive component 50.6. In this case, the input signal E is different from the initial rectangular shape and shows a rising-then-falling amplitude of the individual pulses over time as a result of the modulation. Further signal shaping can be achieved, for example, directly by the drive mechanism 50.1 when the input signal E is generated. Diagram IV shows a further development, in which, in addition to the modulation according to III, a further modulation is used. The input signal E has a staircase shape, which may facilitate filtering by means of the transmission means 30. In other words, according to diagram III, the drive assembly 50.6 and/or the drive mechanism 50.1 may be designed to perform the shaping of the input signal E by generating a rectangular signal with temporally successive pulses, where the pulse amplitudes of the different pulses vary with time, preferably with increasing amplitude followed by decreasing amplitude with time (in particular within a pulse train), where the pulse amplitude of each pulse preferably remains (substantially) constant over the pulse width. In the diagram IV, the pulse amplitude of each pulse may additionally vary with time within the pulse width, and preferably has a step shape. In this way, a sinusoidal output signal a can be generated very reliably.

A particularly advantageous example of an input signal E is shown in diagram V. This signal can be obtained, for example, by shaping the signal, which is provided by the drive mechanism 50.1 and/or the drive assembly 50.6. For this purpose, the drive assembly 50.6 is designed, for example, as a programmable voltage divider. The shape shown has a plurality of temporally successive rectangular pulses which differ from one another in terms of pulse amplitude. For this purpose, the drive unit 50.6 can output drive signals from the drive means 50.1 via different lines, which are each connected to at least one resistor of the drive unit 50.6. It is designed, for example, in the form of pulse width modulation or the like and is different for different lines. The resistances of the different wires are for example of different magnitudes. In this way, the input signal E can be generated very precisely in the desired shape. Particularly advantageous frequency spectra can be generated by means of shape symmetry, in particular with identical rising-falling pulse sequences and/or with constant absolute values of the amplitude differences for the different pulses. In particular, third harmonics in the spectrum of the input signal E can thereby be (perhaps completely) cancelled.

The above description of embodiments describes the invention by way of example only. It is clear that the individual features of the embodiments can be freely combined with one another as far as technically expedient without departing from the scope of the invention.

List of reference numerals

1 vehicle

2 trunk cover

3 Bumper

8 user

9 body part, activation Medium

10 assembly, circuit assembly

20 sensor mechanism

20.1 sensor electrode, sensor element

20.2 ground potential

30 conveying mechanism

30.1 input terminal

30.2 output terminal

30.3 Source mechanism, Current Source mechanism and/or Voltage Source mechanism

30.4 first Filter element, RC Circuit for 1 st order Low pass Filtering

30.5 second filter element for other components of 2 nd order low pass filtering

40 input Signal Source, digital Signal Generation

50 controller

50.1 drive mechanism, microcontroller

50.2 analog-to-digital converter

50.3 adjustment mechanism, software

50.4 holding mechanism

50.5 Low pass Filter

50.6 drive assembly

50.7 other controls

60 switch mechanism

80 prefilter assembly, preselector

80.1 first terminal, supply terminal

80.2 second, ground terminal

r receiving path

t sending path

A output signal

C capacitor

CH holding capacitance

CS sensor capacitance

E input signal

O output terminal

OP operational amplifier

OP' other operational amplifiers

L coil

R resistance

S-switch element

u transmission path

First voltage of U1

U2 second voltage

VC supply voltage, second potential

VE supply voltage, first potential