Sensor arrangement with strain sensor and proximity sensor

Abstract

The invention relates to a sensor arrangement (50) comprising a strain sensor (10) and a capacitive proximity sensor. The strain sensor (10) is configured to detect deformation of a component to which it is connected. The proximity sensor is configured to detect an operator's approach to the proximity sensor based on a measurement of the intrinsic capacitance of a measuring electrode. The strain sensor (10) forms the measuring electrode of the capacitive proximity sensor. The invention also relates to the use of a strain sensor (10).

Description

Technical area

[0001] The present invention relates to a sensor arrangement. Furthermore, the invention relates to the use of a strain gauge. State of the art

[0002] Sensor arrays can be used to detect the actuation of an element. For example, sensor arrays are installed in vehicles to detect the actuation of a door handle. A door lock can then be unlocked in response to this actuation, for example, if a vehicle key is detected near a vehicle door. It is desirable for this reaction to occur without any delay noticeable to the user. Furthermore, power consumption should be low to avoid excessive strain on the vehicle's power supply.

[0003] Sensor arrays are installed in vehicles that can detect the deformation of a component. This allows such a component to be installed immobile in the vehicle and still be activated by the user, for example, by pulling or grasping. A vehicle function can then be controlled in response. This allows the component to be easily integrated into the vehicle. Wear can also be minimal, since, for example, relative movement on a hinge is eliminated.

[0004] EP 3 511 146 EP describes a method for manufacturing a strain gauge. The strain gauge manufactured in this way can, for example, be installed in a steering wheel to detect whether a driver is gripping the steering wheel or not. It also describes how the strain gauge can be combined with another sensor, such as a capacitive measuring device, for verification purposes. The capacitive measuring device is manufactured together with the strain gauge. The strain gauge can form one electrode of an electrode pair of the capacitive measuring device. However, the two sensor devices take up a considerable amount of space, and transmission and evaluation of their different sensor signals must be provided. Description of the invention

[0005] A first aspect of the present invention relates to a sensor arrangement comprising a strain sensor and a capacitive proximity sensor. The sensor arrangement can be configured to output respective strain measurement signals and / or capacitive proximity signals. The sensor arrangement can also be configured to evaluate and output respective measurement signals, and / or to generate control signals depending on the measurement signals. The sensor arrangement can have respective conductors for transmitting respective signals.

[0006] The strain sensor is designed to detect a deformation of a component to which the strain sensor is connected. The strain sensor can, for example, have one or more strain gauges. The component can be a component of a vehicle, such as a handle, button, or switch. The component can be immovably mounted. The component can be rigid, for example, made of plastic or metal. The detected deformation can therefore be very small compared to a component dimension. The component can, for example, be designed for actuation and / or generally have a rigidity necessary for deformation measurements. The deformation can, for example, occur through pulling, gripping, touching, or some other actuation of the component, in particular by a user with their hand. The strain sensor can, for example, be glued or welded to the component for connection.The strain sensor can be arranged within the component. For example, the strain sensor can be cast into a plastic part of the component. The strain sensor can also be attached to the outside of the component. The strain sensor can also be integrated into the component as a single piece for connection, for example, by means of etched conductor tracks in the component. The sensor arrangement can comprise multiple strain sensors, for example, to be able to detect deformation redundantly, for temperature compensation, and / or to detect deformation in different directions.

[0007] The proximity sensor is designed to detect the approach of an operator to the proximity sensor based on a self-capacitance measurement of the measuring electrode. For example, the proximity sensor can be designed to detect the approach of an operator's hand below a predetermined distance. A self-capacitance measurement can be a measurement of a capacitance in relation to a ground connection. Accordingly, a self-capacitance measurement can, for example, dispense with a capacitor or a second capacitance, for example in the form of a measuring electrode. The capacitance can be an electrical capacitance, which is measured, for example, in the unit farad. The capacitance can be a storage capacity for electrical charge. The capacitance of a measuring electrode of the proximity sensor can change when another electrical capacitance, such as a hand, approaches.By using self-capacitance as a measuring principle, the proximity sensor can be easily integrated and requires few components.

[0008] The sensor arrangement can also comprise multiple proximity sensors, for example, to be able to detect the operator's approach redundantly and / or to detect an approach from different directions differently. By providing multiple proximity sensors, it is also possible to determine the position of the operator or a body part of the operator, such as their hand, within a detection range of the proximity sensor.

[0009] The strain sensor forms a measuring electrode of the capacitive proximity sensor. For example, a strain gauge and / or a Wheatstone bridge can form the measuring electrode. The measuring electrode of the proximity sensor can be an electrode whose capacitance is measured to detect the approach of the operator. This allows the sensor arrangement to be particularly compact and cost-effective. Furthermore, additional conductor tracks for integrating the proximity sensor can be omitted if necessary. The strain sensor can, for example, be used simultaneously or selectively to detect approach and deformation. For example, one capacitive proximity sensor can be formed per strain sensor, with each strain sensor then forming a measuring electrode. However, only some of a plurality of strain sensors can each form a measuring electrode of the capacitive proximity sensor.The strain sensor can have multiple sensor elements, one or more of which can form the measuring electrode. For example, several strain gauges or electrical resistors of a Wheatstone bridge can jointly form the measuring electrode. Several strain sensors can also jointly form the measuring electrode of a capacitive proximity sensor.

[0010] In a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement has an actuating element. The actuating element can, for example, be designed as a stationary door handle of a vehicle. The sensor arrangement can, for example, be arranged on or in the actuating element. The sensor arrangement can thus be provided as a module that can be easily installed. For example, the component can thus form a door handle with integrated actuating sensors. The strain sensor can be designed to detect a deformation of the actuating element. The proximity sensor can be designed to detect an approach of the operator to the actuating element. The actuating element can be designed to be immovable relative to another component to which the actuating element is attached.

[0011] Additionally, the sensor arrangement can comprise a vehicle door and / or parts of a vehicle body. A further aspect relates to a vehicle door arrangement or vehicle handle arrangement with the sensor arrangement according to the first aspect. Respective advantages and further features can be found in the description of the first aspect, with embodiments of the first aspect also forming embodiments of these further aspects, and vice versa.

[0012] In a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement has a shielding element. The shielding element can be designed, for example, as a metallic shielding element. The shielding element can be designed as a grounded electrode. The grounding can be formed, for example, by a connection to a vehicle. The shielding element can influence and, in particular, shield a field of the measuring electrode. This allows for directed detection of the operator's approach. The shielding element is designed to shield a change in capacitance of the proximity sensor caused by the operator approaching from at least one side. For example, this only allows the operator's hand to approach the door handle to be detected if it is pushed into a recess behind the door handle from above or below. The approach can also occur by changing your grip.However, a mere frontal approach to the door handle from the outside is no longer detected by the proximity sensor due to the shielding element. This can prevent unintentional detection and / or triggering of an actuation reaction. Furthermore, specific areas can be specified in which the approach is detected. The sensor arrangement can therefore be particularly well-suited to controlling a function. The shielding element can be arranged, for example, on the actuating element, the vehicle door, or the vehicle body. The shielding element can, for example, be a trim part on the actuating element, be cast into the actuating element, or be formed by the actuating element itself. The shielding element can also, for example, be formed by the vehicle door or be designed as part of the vehicle body. The shielding element can be grounded together with the strain sensor.A plurality of shielding elements may also be provided to define a detection range of the proximity sensor or the plurality of proximity sensors.

[0013] In a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement is designed to detect either the deformation or the approach of the operator. The sensor arrangement can, for example, be operated selectively with one of two sensor modes. A first mode can be a proximity detection mode and a second mode a deformation detection mode. For example, the sensor arrangement can be operated alternately, in particular periodically alternating, with one of the two modes. This allows the sensor arrangement to be operated in a particularly power-efficient manner. For example, the detection can take place alternately at a high frequency. For example, in response to a detected approach of the operator below a predetermined minimum distance, a switch can be made from the proximity detection mode to the deformation detection mode.This makes it possible, for example, to avoid with a high degree of probability detecting a deformation that was not caused by the operator and thus an actuation.

[0014] In a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement is designed to simultaneously detect the deformation and the approach of the operator. For this purpose, for example, an evaluation channel for deformation detection and an evaluation channel for approach detection can be provided. For example, two sensor signals can be output simultaneously by the sensor arrangement. This allows a sensor signal to be verified. The sensor arrangement can then, for example, simultaneously detect approach and deformation. Optionally, the sensor arrangement can be designed to be operated either with simultaneous detection or only for detecting deformation or approach.

[0015] In a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement has an evaluation device which is designed to evaluate respective sensor signals from the strain sensor and the proximity sensor. For example, the evaluation device can have a microcontroller or consist of a microcontroller. The evaluation device can, for example, convert electrical signals from the strain sensor and the proximity sensor into measured values. The evaluation device can also be designed to switch between different sensor modes. The evaluation device can be connected to the measuring electrode or the strain sensor, for example with at least one electrical line. The evaluation device can, for example, be designed to convert electrical signals from the strain sensor and the proximity sensor into control signals.

[0016] In a further embodiment of the sensor arrangement, it can be provided that the evaluation device has at least one data input, which is connected to the strain sensor and is designed to receive both deformation measurement signals and capacitance change measurement signals. This makes the evaluation device particularly simple and cost-effective. For example, separate data inputs for the capacitive proximity measurement and the deformation measurement can be dispensed with. A data input can, for example, be designed as a connection for an electrical line. The measurement signals can, for example, be voltage changes and / or current flow changes at the data input. The evaluation device can have a further data input, which is used for measuring the deformation. Both data inputs can be electrically connected to the strain sensor.

[0017] In a further embodiment of the sensor arrangement, it can be provided that the evaluation device has a first data input, which is designed to receive deformation measurement signals. The first data input can, for example, receive exclusively deformation measurement signals. The evaluation device can have a second data input, separate from the first data input, which is designed to receive capacitance change measurement signals. The second data input can, for example, receive exclusively capacitance change measurement signals. The separate data inputs make it easy to simultaneously detect the deformation and the approach of the operator. The second data input can be coupled to the strain sensor via a capacitor for signal transmission. The electrical current flow to the second data input can thus be interrupted.This prevents the capacitive proximity measurement from influencing the deformation measurement. For example, the capacitor may have a capacitance that is significantly larger than the capacitance to be measured. For example, the capacitor's capacitance may be an order of magnitude or more larger. For example, the capacitor may have a capacitance of 2.2 nF, and the measured capacitance, for example, in the case of a proximity measurement of an operator's hand, may be less than 10 pF. The evaluation device may have an additional data input used for measuring the deformation. The first and the additional data input may be electrically connected to the strain sensor.

[0018] In a further embodiment of the sensor arrangement, the sensor arrangement may include a power source configured to supply the strain sensor with power. For example, the power source may be configured as a voltage source. The power source may be a vehicle's electrical system. The power source may, for example, be configured to provide a direct current.

[0019] The sensor arrangement can have a switching device which is designed to electrically separate the strain sensor from the energy source in a disconnected state. This can, for example, separate the strain sensor from the energy source in order to function as a measuring electrode of the capacitive proximity sensor. Alternatively or additionally, the sensor arrangement can, for example, be switched off. The switching device can be designed to be switched between a connected state and a disconnected state. In the disconnected state, the sensor arrangement functions, for example, only as a proximity sensor and no deformation is detected. In the connected state, the sensor arrangement functions, for example, only as a strain sensor and no operator approach is detected. In the disconnected state, the energy source can be separated from the strain sensor and thus also from the measuring electrode.In the connected state, the energy source can be connected to the strain sensor and thus also to the measuring electrode. In the disconnected state, for example, one or more electrical connections between the strain sensor and the energy source can be interrupted.

[0020] For example, the strain sensor has a first contact and a second contact. The switching device can, for example, have a first switching element, by means of which the first contact can be connected to the energy source. If the switching device has only one switching element, the evaluation device can, for example, have a separate data input for the proximity sensor, coupled via a capacitor. The switching device then switches the strain sensor on and off, for example. The switching device can, for example, have a second switching element, by means of which the second contact can be connected to ground and / or by means of which the second contact can be connected to the energy source.By disconnecting both contacts from the power source, the proximity detection mode can be switched on, for example, if the same data input is configured to receive both deformation measurement signals and capacitance change measurement signals. The two switching elements can each be configured as MOSFETs, for example. Both switching elements can be controlled by the evaluation device or the microcontroller.

[0021] In a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement has a control device which is designed to output control signals in response to the detected deformation of the component and / or to the detected approach of the operator. The control device can have a microcontroller. The control device and the evaluation device can be jointly formed by the same microcontroller. The control device can form part of the evaluation device. For example, a first control signal can be output when a predetermined minimum deformation is exceeded. For example, a second control signal can be output when a predetermined maximum distance is undershot by the operator's hand. For example, only one control signal can be output depending on the detected approach of the operator and the detected deformation of the actuating element.This makes it easy to implement sensor fusion for control.

[0022] In a further embodiment of the sensor arrangement, the control device can be configured to switch from a proximity detection mode to a deformation detection mode in response to the detected approach of the operator. This can avoid a delay in the detection of deformation for actuation. For example, a lock actuator can be energized at a certain maximum distance from the operator, access authorization can be checked, and / or the deformation detection mode can be activated to open the door without delay when a door handle is grasped.

[0023] In a further embodiment of the sensor arrangement, the strain sensor can have at least a first sensor element and a second sensor element. More sensor elements can also be provided. The sensor elements can be designed, for example, as resistors of a Wheatstone bridge or as strain gauges. The first sensor element and the second sensor element can together form the measuring electrode of the capacitive proximity sensor. With more sensor elements, some or all of the sensor elements can form the measuring electrode of the capacitive proximity sensor. For example, the sensor elements are electrically connected to one another at least when detecting the approach of an operator or even permanently. In this way, the sensor elements can together form a larger measuring electrode, which can be particularly sensitive.In addition, the sensor elements can be spaced apart from each other, which allows the approach to be detected over a larger area.

[0024] In a further embodiment of the sensor arrangement, it can be provided that the sensor arrangement has a reinforcement element which is capacitively coupled to the measuring electrode of the capacitive proximity sensor and which is galvanically decoupled. The reinforcement element can be designed, for example, as a metal plate or metal foil. The reinforcement element can also be designed to press the respective sensor elements, such as strain gauges or resistors, against the component whose deformation is to be detected. For this purpose, the reinforcement element can be designed, for example, as a type of spring. The reinforcement element can also be designed to attach the sensor elements to the component. For example, the component whose deformation is to be detected has two plastic shells in which the reinforcement element presses the sensor elements against an inner wall. The reinforcement element is, for example, potential-free.The reinforcement element is, for example, not electrically connected to a vehicle body. The reinforcement element is, for example, not grounded. The reinforcement element is, for example, galvanically decoupled from ground, the remaining sensor arrangement, in particular the sensor elements, the component, and / or a vehicle body. For example, the reinforcement element is not galvanically connected to any other part. The reinforcement element, together with the sensor elements, can form a capacitor whose capacitance is influenced by the approach of an operator. This makes it possible, for example, to provide a capacitive sensor in almost the entire component. Furthermore, very high sensitivity can be achieved. The reinforcement element is, for example, 0.1 mm to 2 mm thick, in particular 0.5 mm to 1 mm. The reinforcement element can be designed as a flat plate or can have a curved shape.

[0025] The sensor elements are embodied, for example, in a printed circuit board (PCB), also known as a printed circuit board (FPC). The printed circuit board can be designed as a flexible printed circuit board (FPC). The flexible printed circuit board can, for example, have a conductive foil. This allows the strain sensor to be designed to be particularly space-saving and easy to integrate even in uneven areas. The printed circuit board can electrically insulate the sensor elements from the reinforcement element. For example, a substrate of the printed circuit board is designed as a dielectric.

[0026] The sensor elements can be attached to the reinforcement element, for example, by bonding. For example, the flexible circuit board can be glued to a reinforcement element formed as a metal plate or printed directly onto the metal plate. This allows for particularly good capacitive coupling. The sensor elements can thus be positioned close to the reinforcement element and essentially maintain their spacing and relative position even when deformed. The sensor elements can be galvanically decoupled from the reinforcement element, for example.

[0027] In a further embodiment of the sensor arrangement, the proximity sensor can be provided with the strain sensor as the only measuring electrode. This makes the sensor arrangement compact, cost-effective, and easy to integrate. For example, no second measuring electrode can be provided for the proximity sensor. The proximity sensor can be free of additional measuring electrodes and, optionally, also of shielding electrodes.

[0028] In a further embodiment of the sensor arrangement, the strain sensor can be designed as a Wheatstone bridge. The Wheatstone bridge can, for example, comprise four resistors connected together to form a closed ring or square. The voltage source can then be connected in one diagonal, and a voltmeter or evaluation device can be connected in another diagonal.

[0029] A second aspect relates to the use of a strain sensor, in particular a strain gauge. The strain sensor can be used both as a strain sensor and as a measuring electrode of a capacitive proximity sensor. The proximity sensor is designed to detect an operator's approach to the proximity sensor based on a self-capacitance measurement of the measuring electrode. The use according to the second aspect can form a sensor arrangement according to the first aspect. Respective advantages and further features can be derived from the description of the first aspect, with embodiments of the first aspect also forming embodiments of these further aspects and vice versa. During use, the strain sensor can be used alternately for deformation detection and proximity detection or also simultaneously for deformation detection and proximity detection. Short description of the characters Fig. 1 schematically illustrates a strain sensor according to the prior art. Fig. 2 schematically illustrates a first embodiment of a sensor arrangement in which a strain sensor forms a measuring electrode of a capacitive proximity sensor. Fig. 3 schematically illustrates a second embodiment of a sensor arrangement in which a strain sensor forms a measuring electrode of a capacitive proximity sensor. Fig. 4 shows a schematic perspective view of a vehicle door with a fixed door handle. Fig. 5 illustrates in a schematic plan view how the sensor arrangement according to Fig. 2 or Fig. 3 can be installed in the door handle. Fig. 6 schematically illustrates parts of a third embodiment of a sensor arrangement in which several sensor elements form a measuring electrode of a capacitive proximity sensor and an amplification element is provided. Fig. 7 schematically illustrates parts of the third embodiment in a side view. Fig. 8 schematically illustrates parts of the third embodiment in a plan view. Detailed description of embodiments

[0030] Fig. 1 shows a strain sensor 10 according to the prior art. The strain sensor 10 has a Wheatstone bridge comprising four interconnected resistors 12, 14, 16, and 18. A current-carrying conductor of a 3.3 V voltage source is connected between the resistors 12 and 14, and the Wheatstone bridge is grounded between the resistors 16 and 18. A data input 22, 24 of an evaluation device 20 is connected to the Wheatstone bridge between the resistors 12 and 16, and between the resistors 14 and 18. The evaluation device 20 can thus measure a voltage in the Wheatstone bridge caused by a deformation. This allows the strain sensor 10 to detect a deformation. The evaluation device 20 is powered by another or the same 3.3 V voltage source and is also grounded.The evaluation device 20 can control a switching element 28 of a switching device, embodied as a MOSFET, via a control output 26. This allows the power supply of the strain sensor 10 to be disconnected in order to switch it off.

[0031] Fig. 2 shows a sensor arrangement 50, which has a strain sensor 10 according to Fig. 1 has a similarly constructed strain sensor 10. This strain sensor 10 also has a Wheatstone bridge, which comprises four interconnected resistors 12, 14, 16, and 18. A current-carrying conductor of a 3.3 V voltage source is connected between resistors 12 and 14, and the Wheatstone bridge is grounded between resistors 16 and 18. A data input 22, 24 of an evaluation device 20 is connected to the Wheatstone bridge between resistors 12 and 16, and between resistors 14 and 18. The evaluation device 20 can thus measure a voltage in the Wheatstone bridge caused by a deformation. In this way, the strain sensor 10 can detect a deformation of a component to which the strain sensor 10 is connected. The evaluation device 20 is supplied with power from another or the same 3.3 V voltage source and is also grounded.

[0032] The sensor arrangement 50 also has a capacitive proximity sensor, which is designed to detect an operator's contact with the proximity sensor based on a self-capacitance measurement of a measuring electrode. The measuring electrode is formed by the strain sensor 10. In order to use the sensor arrangement 50 according to Fig. 2 To detect the approach of the operator, the Wheatstone bridge or the measuring electrode formed thereby is disconnected from the voltage source and also from its ground. For this purpose, the sensor arrangement 50 has a switching device with a first switching element 28 and a second switching element 30. Both switching elements 28, 30 are designed as MOSFETs and can be switched by means of the evaluation device 20. For this purpose, the evaluation device 20 has a first control output 26 and a second control output 32. However, only one control output can also be provided, whereby both switching elements 28, 30 are always connected together. The evaluation device 20 can adjust the switching device to a connected state in which the Wheatstone bridge is connected to the voltage source and ground.The evaluation device 20 can adjust the switching device to a disconnected state in which the Wheatstone bridge is disconnected from the voltage source and ground. The first switching element 28 is designed for disconnection from the voltage source, and the second switching element 30 is designed for disconnection from ground.

[0033] In the disconnected state, the strain sensor 10 or the Wheatstone bridge acts as the measuring electrode of the capacitive proximity sensor. When an operator approaches the sensor, for example, with their hand, the capacitance of the Wheatstone bridge can change. This is detected by the evaluation device 20 via the data input 24 or, optionally, both data inputs 22, 24, using the principle of self-capacitance measurement.

[0034] The sensor arrangement 50 according to Fig. 2 is thus configured to detect either the deformation or the operator's approach. The data input 24 of the evaluation device 20 is configured to receive both deformation measurement signals and capacitance change measurement signals. The sensor arrangement 50 can be switched between a proximity detection mode and a deformation detection mode using the switching device.

[0035] Optionally, the sensor assembly 50 includes a shielding element in the form of the metallic vehicle body 34, which is grounded together with the strain sensor 10. The shielding element influences a field of the measuring electrode of the proximity sensor in order to shield a change in the capacitance of the proximity sensor caused by the operator approaching from a side of the vehicle body 34 facing away from the strain sensor 10.

[0036] Fig. 3 shows a sensor arrangement 50 which corresponds to the sensor arrangement 50 according to Fig. 2 is similarly constructed and also features a strain sensor 10 and a proximity sensor operating on the basis of self-capacitance. Therefore, only the differences will be explained.

[0037] In the sensor arrangement 50 according to Fig. 3, the switching device has only the first switching element 28, by means of which the Wheatstone bridge can be separated from the voltage source. The Wheatstone bridge remains permanently grounded. For this purpose, the evaluation device 20 has an additional data input 36, which is designed to receive capacitance change measurement signals. This data input 36 is coupled to the strain sensor 10 via a capacitor 38 for signal transmission. The other two data inputs 22, 24, however, are electrically connected directly to the Wheatstone bridge. Thus, the sensor arrangement 50 can simultaneously detect the approach of the operator and the deformation of the component.

[0038] Fig. 4 and Fig. 5 show a concrete application of the sensor arrangement 50. Fig. Figure 4 illustrates a schematic perspective view of a vehicle door 60 with a door handle 62 as the actuating element. The door handle 62 is immovably attached to the rest of the vehicle door 60. The vehicle door 60 and / or the door handle 62 can also form part of the sensor arrangement 50.

[0039] In Fig. Figure 5 illustrates the arrangement of the sensor arrangement 50 on the door handle 62. The sensor arrangement 50 here has two strain sensors 10, which can also be designed as strain gauges. The strain gauges then also form a measuring electrode for each associated proximity sensor, which operates based on self-capacitance measurement. The two strain sensors 10 are molded or glued into a plastic base body 64, which is attached to a holder 66. When the user places their hand between the door handle 62 and the vehicle door 60, the operator's approach is detected. The evaluation device 20 (not shown here) can then switch to deformation detection mode and / or activate a door opening device in response. If the operator now grasps the door handle 62 and pulls on it, a slight deformation of the door handle 62 occurs, which is either imperceptible or barely noticeable to the operator.This is detected by the strain sensors 10. The evaluation device 20 can then control the door opening device in response to this to open a door lock without delay. By providing two strain sensors 10 and two corresponding proximity sensors, the detection can be verified and / or redundancy can be provided.

[0040] The Fig. 6 to 7 illustrate, as a third embodiment, a modification of the previously described embodiments of the sensor arrangement 50. In comparison, a reinforcement element 70 in the form of a metal plate is additionally provided. This reinforcement element 70 is galvanically decoupled from the remaining sensor arrangement 50 and ground. The reinforcement element 70 is capacitively coupled to the measuring electrode of the capacitive proximity sensor. The reinforcement element 70 forms a virtual capacitor with an approaching hand 74 of a user, as shown in Fig. 6. The approach of the hand 74 can thus be detected particularly sensitively over a large area.

[0041] This measuring electrode is formed by four sensor elements 12, 14, 16, 18 of the sensor arrangement 50. For example, in the third embodiment, the four sensor elements 12, 14, 16, 18 are also formed by the four resistors 12, 14, 16, 18 of the Wheatstone bridge. Alternatively, the four sensor elements 12, 14, 16, 18 are each designed as strain gauges. In principle, the remaining components of the sensor arrangement 50, which are shown in Fig. 6 to 8 are not shown, and their interconnection may be designed as in the previously described embodiments.

[0042] In the third embodiment, the four sensor elements 12, 14, 16, 18 are formed in a flexible printed circuit board 72. A substrate 76 of the printed circuit board 72 is a dielectric and forms a galvanic isolation between the four sensor elements 12, 14, 16, 18 and the reinforcement element 70. The printed circuit board 72 is connected to the reinforcement element 70 in a planar manner. In one embodiment, the reinforcement element 70 presses the sensor elements 12, 14, 16, 18 against a plastic half-shell of the door handle 62 in a spring-like manner, which also allows for particularly good detection of deformation. List of reference symbols 10 Strain sensor / measuring electrode 12,14,16,18 resistance 20 Evaluation device / control device 22, 24, 36 Data input 26 first control output 28 first switching element 30 second switching element 32 second control output 34 Vehicle body / shielding element 38 Capacitor 50 Sensor arrangement 60 vehicle door 62 door handle 64 plastic base bodies 66 bracket 70 Reinforcing element 72 circuit board 74 Hand of a user 76 Substrat QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 511 146

[0004]

Claims

[1] Sensor arrangement (50) with a strain sensor (10) and a capacitive proximity sensor, wherein the strain sensor (10) is designed to detect a deformation of a component to which the strain sensor (10) is connected, wherein the proximity sensor is designed to detect an approach of an operator to the proximity sensor based on a self-capacitance measurement of a measuring electrode, and wherein the strain sensor (10) forms the measuring electrode of the capacitive proximity sensor. [2] Sensor arrangement (50) according to claim 1, wherein the sensor arrangement (50) has an actuating element, in particular an actuating element designed as a stationary door handle (62) of a vehicle, and wherein the strain sensor (10) is designed to detect a deformation of the actuating element. [3] Sensor arrangement (50) according to claim 1 or 2, wherein the sensor arrangement (50) has a shielding element (34), in particular a metallic shielding element (34), wherein the shielding element (34) is designed to shield a change in capacitance of the proximity sensor due to the approach of the operator from at least one side. [4] Sensor arrangement (50) according to one of the preceding claims, wherein the sensor arrangement (50) is designed to detect either the deformation or the approach of the operator, or wherein the sensor arrangement (50) is designed to simultaneously detect the deformation and the approach of the operator. [5] Sensor arrangement (50) according to one of the preceding claims, wherein the sensor arrangement (50) has an evaluation device (20) which is designed to evaluate respective sensor signals from the strain sensor (10) and the proximity sensor. [6] Sensor arrangement (50) according to claim 5, wherein the evaluation device (20) has at least one data input (22, 24) which is connected to the strain sensor (10) and is designed to receive both deformation measurement signals and capacitance change measurement signals. [7] Sensor arrangement (50) according to claim 5, where the evaluation device a first data input (22, 24) which is designed to receive deformation measurement signals, and a second data input (36) separate from the first data input (22, 24) which is designed to receive capacitance change measurement signals, wherein the second data input (36) is coupled to the strain sensor (10) via a capacitor (38) for signal transmission. [8] Sensor arrangement (50) according to one of the preceding claims, wherein the sensor arrangement (50) has an energy source which is designed to supply the strain sensor (10) with energy, wherein the sensor arrangement (50) has a switching device (28, 30) which is designed to electrically separate the strain sensor (10) from the energy source in a disconnected state. [9] Sensor arrangement (50) according to one of the preceding claims, wherein the sensor arrangement (50) comprises a control device (20) which is designed to output control signals in response to the detected deformation of the component and / or to the detected approach of the operator. [10] Sensor arrangement (50) according to claim 9, wherein the control device (20) is configured to change from a proximity detection mode to a deformation detection mode in response to the detected approach of the operator. [11] Sensor arrangement (50) according to one of the preceding claims, wherein the strain sensor (10) has at least a first sensor element (12) and a second sensor element (14), wherein the first sensor element (12) and the second sensor element (14) together form the measuring electrode of the capacitive proximity sensor. [12] Sensor arrangement (50) according to one of the preceding claims, wherein the sensor arrangement (50) comprises a gain element (70) which is capacitively coupled to the measuring electrode of the capacitive proximity sensor and which is galvanically decoupled. [13] Sensor arrangement (50) according to one of the preceding claims, wherein the proximity sensor has the strain sensor (10) as the only measuring electrode. [14] Sensor arrangement (50) according to one of the preceding claims, the strain sensor (10) is designed as a Wheatstone measuring bridge. [15] Use of a strain sensor (10), in particular a strain gauge, both as a strain sensor (10) and as a measuring electrode of a capacitive proximity sensor, wherein the proximity sensor is configured to detect an approach of an operator to the proximity sensor based on a self-capacitance measurement of the measuring electrode.

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