Haptic device

Abstract

The invention relates to a haptic device (100) for detecting a haptic input, said haptic device comprising: a piezoelectric actuator (1) having a main body (11) comprising a piezoelectric material; a first reinforcement element (13a) on a first main surface (11a) of the piezoelectric actuator (1); and a first capacitive element (30a), wherein the first reinforcement element (13a) is attached to the piezoelectric actuator (1) and has a touch region (17a) that is positioned at a distance above the first main surface (11a), wherein the first reinforcement element (13a) forms a first electrode (31a) of the first capacitive element (30a), wherein a second electrode (32a) of the first capacitive element (30a) is arranged on a main surface (11a, 11b) or inside the main body (11).

Description

[0001] Description

[0002] Haptic device

[0003] A haptic device is specified. Such a device has an actuator that generates and / or detects a movement of a movable element. The movable element is designed, for example, as a touch-sensitive surface or tip of a pen-like device. The actuator is, for example, a piezoelectric actuator, in particular a piezoceramic actuator.

[0004] The haptic device can, for example, be designed to generate haptic feedback upon touch. The haptic device can, for example, be used in a touchscreen, trackpad, push button, or stylus (pen-like device). In particular, the haptic device can be used in the automotive sector.

[0005] Devices for generating haptic feedback are known from the publications WO 2017 / 060 011 A1, WO 2018 / 046 201 A1, and WO 2022 / 248 244 A1, in which a reinforcement element for stroke amplification is attached to a piezoelectric actuator. The reinforcement element is designed, for example, in the form of a metal sheet.

[0006] For example, such devices can also operate as sensors, perhaps by using the inverse piezoelectric effect, in which mechanical energy is converted into electrical energy. However, piezoelectric sensors are "dynamic" sensors, meaning they can only measure mechanical changes, not a static mechanical force. Thus, it is physically impossible for such known devices to detect, for example, a human finger continuously pressing a switch equipped with such a device over an extended period of time. For the same reason, it is impossible to use the known devices for a piezoelectric sensor that always triggers at exactly a certain pressure, for example 3 N, which corresponds to a typical force trigger requirement for switches in the automotive sector.This is because, due to its dynamic characteristics, the piezoelectric sensor would output a very different electrical signal depending on whether the force of 3 N was reached in, say, 10 ms or about 10 s. Due to these dynamic sensor characteristics, piezoelectric sensors can typically only be used in simple applications for non-critical functions, such as doorbells, vending machines, or consumer goods.

[0007] In recent years, the demand for user interfaces with haptic feedback has increased. Piezo-based components make excellent haptic actuators. However, haptic feedback is particularly desirable in the automotive sector, for example, for safety reasons, and in other sophisticated user interfaces where tactile feedback is essential for an improved user experience. Haptic feedback is therefore particularly in demand where a reliable and precise force sensor is also required, which, however, is usually provided by a separate, additional sensor, resulting in increased space and cost.

[0008] At least one object of certain embodiments is to provide a haptic device.

[0009] This object is achieved by an object according to the independent patent claim. Advantageous embodiments and developments of the object are characterized in the dependent claims and will further emerge from the following description and the drawings.

[0010] According to at least one embodiment, a haptic device is specified. For example, the haptic device can be designed to detect a haptic input. Furthermore, the haptic device can also be designed to output haptic feedback. In other words, the haptic device can, for example, be designed such that a haptic signal from a user can be received by the haptic device. Furthermore, the haptic device can be designed such that a haptic signal can be output to a user. In particular, the haptic device can thus be designed to generate haptic feedback. The haptic device can therefore be designed to provide tactile feedback to a user for certain actions or inputs.

[0011] The haptic device particularly preferably has a piezoelectric actuator. The piezoelectric actuator can be designed to detect a haptic input and / or to output haptic feedback. The piezoelectric actuator can be based on a piezoelectric material, in particular a piezoelectric ceramic material or a piezoelectric polymer material. The piezoelectric actuator can have a base body with the piezoelectric material. Furthermore, one or more electrodes can be provided on and / or in the base body. If no electrodes are present in the base body, i.e. the base body has no internal electrodes, the piezoelectric actuator can be designed as a monolithic actuator, for example as a disk or plate. For example, the piezoelectric actuator can have at least one or a plurality of internal electrodes.In this case, the base body of the piezoelectric actuator can be constructed in a multilayer design with a plurality of piezoelectric layers arranged one on top of the other along a stacking direction, and with the internal electrodes. Furthermore, the piezoelectric actuator can have a longitudinal direction that can be perpendicular to the stacking direction. For example, the longitudinal direction can correspond to a direction with the greatest extension of the base body.

[0012] By applying a suitable electrical signal, the piezoelectric actuator can undergo a change in expansion in at least one direction, whereby this change can be part of the haptic signal. When an alternating voltage is applied, a periodic change and thus a vibration can be generated. In particular, the change in expansion of the piezoelectric actuator can be caused at least by the d31 effect and correspond at least to a change in length of the piezoelectric actuator along the longitudinal direction. Conversely, a mechanical action caused by a haptic input can cause a change in expansion of the base body in at least one direction. Due to the inverse piezoelectric effect, this change in expansion can cause an electrical voltage in the piezoelectric material, which can be detected via the internal electrodes.

[0013] The use of a piezoelectric actuator for detecting and / or generating a haptic signal offers significant advantages. A piezoelectric actuator has a short response and decay time. Accordingly, the time and period in which the haptic signal is detected or generated can be determined very precisely. Furthermore, when generating a haptic signal, the amplitude, frequency and duration at which the piezoelectric actuator vibrates can be determined by varying the control signal applied to the piezoelectric actuator, for example with regard to the frequency, the electrical voltage, the pulse sequence and the signal type. Different control signals can make it possible to generate different haptic signals.

[0014] According to a further embodiment, the haptic device has at least one first mechanical reinforcement element, which is referred to below as the first reinforcement element. The first reinforcement element is attached to the piezoelectric actuator. In particular, the first reinforcement element can be attached to the piezoelectric actuator in such a way that the change in the expansion of the piezoelectric actuator in at least one direction deforms the first reinforcement element, thus moving at least regions of the first reinforcement element.

[0015] Particularly preferably, the first reinforcement element can be attached to the piezoelectric actuator in such a way that, by changing the length of the piezoelectric actuator and in particular of the base body, at least along its longitudinal direction, a region of the first reinforcement element is moved in a direction perpendicular to the longitudinal direction. Furthermore, a direction is also possible that encloses an angle with the longitudinal direction that is greater than 0° and less than 90°. In other words, a region of the first reinforcement element can be moved in a direction oblique to the longitudinal direction.

[0016] In particular, the base body can have a first main surface and a second main surface opposite the first main surface. The first main surface and the second main surface can lie opposite one another along the stacking direction and thus particularly preferably each have a main extension direction along the longitudinal direction described above. The first reinforcing element is applied and fastened on the first main surface of the base body and thus on the first main surface of the piezoelectric actuator.

[0017] According to a further embodiment, the haptic device has at least one second mechanical reinforcement element, which is referred to below as the second reinforcement element. The second reinforcement element is fastened to the piezoelectric actuator. In particular, the second reinforcement element can be fastened to the piezoelectric actuator in such a way that the change in the extension of the piezoelectric actuator in at least one direction deforms the second reinforcement element and thus at least regions of the second reinforcement element are moved. Particularly preferably, the second reinforcement element can be fastened to the piezoelectric actuator in such a way that a change in the length of the piezoelectric actuator along its longitudinal direction moves a region of the second reinforcement element in a direction perpendicular to the longitudinal direction.The second reinforcement element can be applied and secured to the second main surface of the base body and thus to the second main surface of the piezoelectric actuator. Accordingly, the piezoelectric actuator can be arranged between the first reinforcement element and the second reinforcement element along a direction perpendicular to the main surfaces and thus along the stacking direction of the base body.

[0018] According to a further embodiment, the haptic device has a first capacitive element. The first capacitive element has in particular a first electrode and a second electrode and is designed as a capacitive sensor. This means that the first capacitive element is designed to have a variable capacitance depending on a distance between the first electrode and the second electrode. The first amplification element forms the first electrode of the first capacitive element. Furthermore, the second electrode of the first capacitive element is arranged on a main surface of the base body or within the base body. The second electrode of the first capacitive element is particularly preferably arranged on the first main surface of the base body or beneath the first main surface and thus within the base body.Furthermore, the second electrode of the first capacitive element can also be arranged on the second main surface of the base body.

[0019] By detecting the capacitance of the first capacitive element, a conclusion can be drawn about the distance between the first electrode, i.e. the first amplifying element, and the second electrode. The distance between the first electrode, i.e. the first amplifying element, and the second electrode is particularly preferably dependent on a force acting on the first electrode, i.e. the first amplifying element, so that by detecting the capacitance of the first capacitive element, a conclusion can be drawn about a force acting on the first amplifying element. The first capacitive element can thus be designed as a force sensor.

[0020] According to a further embodiment, the haptic device has a second capacitive element. The second capacitive element has in particular a first electrode and a second electrode and is designed as a capacitive sensor. This means that the second capacitive element is designed to have a variable capacitance depending on a distance between the first electrode and the second electrode. The second amplification element forms the first electrode of the second capacitive element. Furthermore, the second electrode of the second capacitive element is arranged on a main surface of the base body or within the base body. The second electrode of the second capacitive element is particularly preferably arranged on the second main surface of the base body or beneath the second main surface and thus within the base body.Furthermore, the second electrode of the second capacitive element can also be arranged on the first main surface of the base body.

[0021] According to a further embodiment, the first capacitive element has a first electrical contact element, with which the first electrode of the first capacitive element can be electrically contacted from the outside. Furthermore, the first capacitive element has a second electrical contact element, with which the second electrode of the first capacitive element can be electrically contacted from the outside. If a second capacitive element is present, it accordingly has a first and second electrical contact element for electrically contacting the first and second electrode of the second capacitive element.

[0022] The following description is limited to the first capacitive element and the first reinforcement element, but applies accordingly to the second capacitive element and the second reinforcement element, if present in the haptic device. The features and properties described above and below for the first reinforcement element can therefore apply accordingly to the second reinforcement element, if present in the haptic device. The first reinforcement element and, if present, the second reinforcement element are particularly preferably designed identically and can therefore have the same features and properties. Furthermore, the features and properties described above and below for the first capacitive element can therefore apply accordingly to the second capacitive element, if present in the haptic device.For example, features and properties described for the first and second electrodes of the first capacitive element can also apply to the first and second electrodes of the second capacitive element. The same applies to all other components described in connection with the first capacitive element.

[0023] For example, the first capacitive element and, if present, the second capacitive element are of identical design and can thus have the same features and properties, so that when a force is applied to the haptic device, at least substantially identical capacitive signals can be detected at the two capacitive elements. This can, for example, achieve redundancy. Alternatively, the first capacitive element and the second capacitive element can be of different design and, for example, have different capacitances which depend on a distance between the respective first and second electrodes, so that when a force is applied to the haptic device, different capacitive signals can be detected at the two capacitive elements.

[0024] The haptic device described here goes beyond a purely haptic piezoelectric component in that at least the first capacitive element is integrated into the haptic device. The integration of the first capacitive element is achieved in particular by the first amplification element having a dual function, namely a mechanical function in cooperation with the piezoelectric actuator and an electrical function in connection with the first capacitive element.

[0025] The first reinforcing element can comprise or be made of metal, for example steel and / or titanium. For example, the first reinforcing element can be plate-shaped. Furthermore, the first reinforcing element can be flat, i.e. as a flat plate, which is fastened to the piezoelectric actuator by at least one edge region or over its entire surface. For example, the first reinforcing element can also be a metal bracket which is fastened, for example, by at least one or preferably two edge regions to one or two end regions along the longitudinal direction of the piezoelectric actuator and which has a central region adjacent to one edge region or between the two edge regions and which is spaced apart from the piezoelectric actuator and is referred to below as the sensing region.Furthermore, the first reinforcing element can be a circular, curved disc, for example based on the shape of a truncated cone or in the manner of a cymbal or a cymbal, which has an edge region which preferably surrounds the sensing region spaced apart from the piezoelectric actuator and which is fastened to the base body.

[0026] The first reinforcement element can be attached to the piezoelectric actuator, for example, by an adhesive bond. If the first reinforcement element is made of titanium, this can have the advantage that its thermal expansion coefficient is very similar to the thermal expansion coefficient of the piezoelectric actuator, so that little or no mechanical stress occurs when temperatures change. As a result, the adhesive bond is subjected to little or no mechanical stress when temperatures change. A dielectric material can be arranged between the sensing region of the first reinforcement element and the first main surface.The dielectric material, by means of which, for example, an adjustment of the capacitance of the first capacitive element and / or electrical insulation between the first and second electrodes can be achieved, can for example comprise one or more materials selected from: air, plastic film, plastic foam. Furthermore, the dielectric material can, for example, achieve fastening of the first reinforcing element to the first main surface. In this case, the dielectric material can enable an adhesive connection and, for example, comprise an adhesive or can be an adhesive that is arranged partially or over the entire area between the first reinforcing element and the first main surface.

[0027] As already described above, the first reinforcing element can convert a change in expansion and particularly preferably a change in length of the piezoelectric actuator into a change in expansion and / or a lifting movement perpendicular or oblique to the change in expansion and preferably the change in length. Conversely, a mechanically induced change in expansion and / or lifting movement, for example by a user, can be converted into a change in expansion and particularly preferably a change in length of the piezoelectric actuator directed perpendicular or obliquely thereto, wherein the direction of the lifting movement in the case of a piezoelectric actuator with a multi-layer construction can preferably correspond to the stacking direction. The lifting movement can have a significantly greater amplitude than the change in length. For example, the amplitude of the lifting movement can be 5 to 40 times the amplitude of the change in length.By combining the piezoelectric actuator with at least the first amplification element, amplification can be achieved.

[0028] The first reinforcing element can be free of notches and have a constant wall thickness. By omitting notches in the first reinforcing element, simple production of the first reinforcing element can be enabled. Furthermore, the first reinforcing element can have at least one notch which reduces mechanical resistance to deformation of the first reinforcing element. In particular, in the case of a reinforcing element with a thickness at which deformation of the reinforcing element would require a great deal of force, the use of notches in the reinforcing element can be useful, since the notches can facilitate deformation of the reinforcing element.

[0029] In addition, the sensing region of the first reinforcing element can have at least one raised region on a bottom side facing the first main surface, which extends towards the first main surface. As a result, a distance between the first electrode of the first capacitive element, formed by the first reinforcing element, and the second electrode of the first capacitive element can be reduced, as a result of which the capacitive signal of the first capacitive element can be improved. For example, the at least one raised region can be formed by an embossed structure introduced from a top side facing away from the first main surface. In other words, the at least one raised region on the bottom side can correspond to a depressed region on the top side of the sensing region, which has been introduced by embossing from the top side of the sensing region.Furthermore, the at least one raised region can be formed by a thickening of the touch region, in particular a thickening which extends to the first main surface.

[0030] According to a further embodiment, the first electrical contact element of the first capacitive element has a first connection region that is electrically conductively connected to the first electrode of the first capacitive element, i.e., the first reinforcement element. The first connection region can particularly preferably be arranged on the first main surface. For example, the first electrical contact element can be formed entirely or partially by an electrically conductive coating on the first main surface.

[0031] The first reinforcing element can be connected to the first connection region of the first electrical contact element, for example via a flexible electrically conductive connecting element, for example an electrically conductive adhesive tape.

[0032] Furthermore, the first electrical contact element can have a fastening region on the first main surface. The fastening region is in particular provided and configured such that the first reinforcing element is at least partially arranged and mounted on the first fastening region. In particular, an edge region of the first reinforcing element can be at least partially electrically conductively fastened to the fastening region of the first electrical contact element. In other words, the entire edge region or only a part of the edge region of the first reinforcing element can be arranged and fastened to the fastening region of the first electrical contact element.The fastening region and the first connection region can be directly adjacent to one another or merge into one another or are connected to one another by means of a conductor track on the main surface or via a conductor track integrated into the base body together with at least one electrical via.

[0033] For example, an edge region or at least part of an edge region of the first reinforcing element can be adhesively bonded to the fastening region by means of an adhesive which forms the adhesive bond described above. The adhesive can be an electrically conductive adhesive, also referred to as a conductive adhesive, for example an adhesive material such as a curable polymer which is filled with electrically conductive particles. Furthermore, the adhesive can be an electrically insulating adhesive which is formed in a layer which is sufficiently thin to nevertheless create electrically conductive contact between the edge region and the fastening region. For this purpose, a thickness of less than or equal to 20 pm can be suitable for the adhesive layer.

[0034] For example, an edge region of the first reinforcing element can be fastened exclusively to the fastening region. In this case, the region of the first main surface covered by the edge region can be provided with the fastening region. Alternatively, the edge region can be fastened partly to the fastening region and partly to the first main surface. This can mean, in particular, that the fastening region is not provided in the entire region of the first main surface covered by the edge region, but rather the adhesive is arranged not only between a part of the edge region and the fastening region, but also between another part of the edge region and a region of the first main surface not covered by the fastening region.For example, the fastening area can run in a serpentine or meandering manner on the first main surface, so that the edge area also covers areas that are free of the material of the fastening area.

[0035] According to a further embodiment, the second electrical contact element of the first capacitive element has a second connection region which is electrically conductively connected to the second electrode of the first capacitive element. The second connection region can particularly preferably be arranged on the first main surface. For example, the second electrical contact element can be formed entirely or partially by an electrically conductive coating on the first main surface. For example, the second contact element can have a conductor track on the first main surface, by means of which the second electrode is connected to the second connection region. Furthermore, an electrically insulating layer can be applied to the conductor track.The electrically insulating layer, for example a plastic film or a plastic coating, can electrically insulate, in particular, the conductor track of the second electrical contact element from the first electrode, i.e., the first reinforcement element. Alternatively, it may also be possible for the second contact element to have at least one electrical via and a conductor track arranged within the base body, through which the second electrode is connected to the second connection region.

[0036] According to a further embodiment, the second electrode is formed by an electrode layer on the first main surface of the base body. For example, the electrode layer is arranged only below the sensing area. In this case, the second electrode can be applied directly to the first main surface and thus directly to the base body of the piezoelectric actuator. Furthermore, the electrode layer forming the second electrode can also be applied on a step and thus on a raised area that is formed on the base body. For example, the raised area can be formed in the first main surface and thus be formed from a material of the base body. Furthermore, the raised area can also have an intermediate layer or be made thereof, for example with or made of a plastic material.Due to the raised area, the second electrode can be arranged closer to the sensing area of ​​the first amplifying element and thus closer to the first electrode, which can lead to an amplification of a capacitive signal of the first capacitive element.

[0037] According to a further embodiment, the second electrode is formed by an electrode layer within the base body. In other words, the second electrode is arranged within the base body below the first main surface. In this case, the second contact element particularly preferably has at least one electrical via through which the second electrode is connected to the second connection region. For example, the electrode layer forming the second electrode can be different from the internal electrodes of the piezoelectric actuator and can be electrically insulated from them, for example by the piezoelectric material of the base body. Alternatively, the second electrode can be formed by at least one internal electrode of the piezoelectric actuator.In this case, said at least one internal electrode has a dual function, namely an electrical function associated with the piezoelectric actuator and an electrical function associated with the first capacitive element. In this case, the second connection region of the first capacitive element can simultaneously be an external electrode for internal electrodes of the piezoelectric actuator.

[0038] If the haptic device has a first capacitive element and a second capacitive element, the two capacitive elements can, for example, each have their own second electrode with one or more of the features described above. Alternatively, the first capacitive element and the second capacitive element can have a common second electrode, for example, at least one electrode layer within the base body, such as at least one internal electrode of the piezoelectric actuator.

[0039] Piezoelectric actuators such as the actuator of the haptic device described here are commonly used as actuators for haptic feedback in user interfaces (UI). In many user interfaces, it is useful to measure the force exerted on the surface by, for example, a finger or an input device, so that the inverse piezoelectric effect could be used when using piezo elements as piezoelectric sensors. However, since piezoelectric sensors measure mechanical energy, i.e., kinetic energy, and not static force, it is technically impossible to use them to measure the actual static force exerted on a piezoelectric sensor, and thus impossible to use it to produce a fully validated "force-based" button.Therefore, a piezoelectric sensor alone cannot be used as a button that triggers at a precisely defined force, for example 3 N, which is a typical requirement for buttons in the automotive sector. Instead of a usually separately used force sensor, the haptic device described here with at least the first capacitive element has an integrated force sensor, which furthermore uses at least the first reinforcement element with its mechanical functionality designed in relation to the piezoelectric actuator additionally with an electrical functionality. The haptic device described here therefore has a simple and robust design compared to usual user interfaces with combinations of piezoelectric actuators and separate force sensors, which can also make it possible to save space and costs.

[0040] Further advantages, advantageous embodiments and further developments emerge from the exemplary embodiments described below in conjunction with the figures.

[0041] Figures 1A to 2B show schematic representations of a piezoelectric actuator with reinforcement elements, Figures 3A and 3B show schematic representations of a haptic device according to an embodiment, Figures 4 to 12 show schematic representations of a

[0042] Haptic device according to further embodiments.

[0043] In the exemplary embodiments and figures, identical, similar, or similarly acting elements may be provided with the same reference numerals. The illustrated elements and their relative sizes are not to be considered true to scale; rather, individual elements, such as layers, components, structural elements, and regions, may be exaggerated for clarity and / or clarity.

[0044] Figures 1A and 1B show an exemplary embodiment of a piezoelectric actuator 1 with reinforcing elements 13a, 13b in a perspective view and a sectional view, which can be used in a haptic device described further below. The piezoelectric actuator 1 shown in Figures 1A and 1B and the reinforcing elements 13a, 13b are to be understood purely as examples in order to explain the functional principle and interaction of the piezoelectric actuator 1 with the reinforcing elements 13a, 13b. Deviations from the exemplary embodiment shown, for example with regard to geometric configurations, are not excluded by the following description.

[0045] The piezoelectric actuator 1 has a base body 11. The base body 11 has a stack of internal electrodes 21 and piezoelectric layers 22 stacked alternately one above the other in a stacking direction S. Even if a plurality of internal electrodes 21 is shown, the base body 11 can, for example, also have only one or two or a different number of internal electrodes 21. Furthermore, the base body 11 can also be free of internal electrodes, so that the base body 11 can be designed as a monolithic disk or plate which is free of internal electrodes. In this case, electrical contact is made exclusively via external electrodes.

[0046] The first reinforcing element 13a is arranged on a first main surface 11a of the base body 11 and thus of the piezoelectric actuator 1, which forms an upper side 25 of the base body 11, and the second reinforcing element 13b is arranged on a second main surface 11b of the base body 11 and thus of the piezoelectric actuator 1, which second main surface 11b lies opposite the first main surface 11a along the stacking direction S and forms an underside 26 of the base body 11. Even if two reinforcing elements 13a, 13b are always shown here and in the following, it is also possible for only the first reinforcing element 13a to be present.

[0047] The piezoelectric actuator 1 further comprises a first outer electrode 23, which may be arranged, for example, on a first end face 24 of the base body 11, and a second outer electrode 23, which may be arranged, for example, on a second end face 24 of the base body 11. Alternatively, the outer electrodes 23 may also be arranged, for example, on one or both main surfaces 11a, 11b, i.e., on the top side 25 and / or the bottom side 26. The inner electrodes 21 are alternately contacted with one of the outer electrodes 23 in the stacking direction S.

[0048] The piezoelectric layers 22 can be, for example, lead zirconate titanate ceramics (PZT ceramics). The PZT ceramic can also contain Nd and Ni. Alternatively, the PZT ceramic can also contain Nd, K and optionally Cu. Alternatively, the piezoelectric layers 22 can have a

[0049] Pb (Zr x Tii- x ) O3 + y Pb (Mni / aNb2 / 3 ) O3 . As an alternative to a piezoelectric ceramic material, a piezoelectric polymer, for example, can also be used. The internal electrodes 21 preferably comprise copper or are particularly preferably made of copper.

[0050] The base body 11 and thus the piezoelectric actuator 1 can preferably be cuboid-shaped, as shown. The base area is a surface whose surface normal points in the stacking direction S. The base area is, for example, rectangular. The longer side of the base area defines the length L of the piezoelectric actuator 11 and the shorter side of the base area defines the width B of the piezoelectric actuator 11. The base body 11 and thus the piezoelectric actuator 1 can, for example, have a length L of greater than or equal to 5 mm and less than or equal to 100 mm and a width B of greater than or equal to 2 mm and less than or equal to 8 mm. The extension of the base body 11 and thus of the piezoelectric actuator 1 in the stacking direction S defines the height H. The height H of the piezoelectric actuator 11 can, for example, be greater than or equal to 200 pm and less than or equal to 3 mm.

[0051] The base body 11 has two insulation regions 12. Each of the insulation regions 12 forms an end region of the base body 11 in the region of the end faces 24. In the insulation regions 12, only internal electrodes 21 of one polarity extend to the respective end face 24 of the base body 11, so that the insulation regions are preferably used for contacting the piezoelectric actuator 1.

[0052] The piezoelectric actuator 1 is designed such that when an electrical voltage is applied to the outer electrodes 23 and thus to the inner electrodes 21, a deformation of the base body 11 takes place, in particular in the multi-layer construction shown with inner electrodes a change in length in the longitudinal direction RI indicated in Figure 1B. In particular, the piezoelectric layers 22 are therefore polarized such that the application of an electrical voltage between the inner electrodes 21 leads to a contraction of the base body 11, in which the length L of the base body 11 changes perpendicular to the stacking direction S. Consequently, an expansion of the base body 11 and thus of the piezoelectric actuator 1 occurs transversely to the polarization direction and to the electric field, which is also referred to as the d31 effect. Other changes in expansion can also be achieved by other configurations with or without inner electrodes in the base body 11.For the sake of clarity, the following description refers, without being understood as limiting, to the multi-layer design shown with the described change in length.

[0053] In order to redirect the effect of the length change in the stacking direction S, the two reinforcement elements 13a, 13b are provided. If a voltage is applied to the piezoelectric actuator 1, the reinforcement elements 13a, 13b deform at least partially as a result of the change in the expansion of the base body 11. In particular, the first and second reinforcement elements 13a, 13b are dimensioned and connected to the base body 11 of the piezoelectric actuator 1 in such a way that a respective sensing area 17a, 17b of the

[0054] Reinforcing elements 13a, 13b, as a result of a change in the length L of the base body 11, carry out a lifting movement in the lifting direction R2 indicated in Figure 1B, corresponding to the stacking direction S, wherein the amplitude of the lifting movement can preferably be greater than the amplitude of the change in the length L of the piezoelectric actuator 1.

[0055] The piezoelectric actuator 1 is, as shown, preferably arranged between the reinforcing elements 13a, 13b. Each of the reinforcing elements 13a, 13b is preferably formed in one piece and, in the exemplary embodiment shown, is strip-shaped with a rectangular basic shape. Furthermore, each of the reinforcing elements 13a, 13b is curved or bent and is bow-shaped. Alternatively, a flat design of the reinforcing elements 13a, 13b is also possible. For example, the reinforcing elements 13a, 13b each have a sheet metal strip or are made thereof, in particular with or from steel and / or titanium.

[0056] Each of the reinforcing elements 13a, 13b is subdivided into several regions or sections. Thus, each reinforcing element 13a, 13b has a central region, which is the aforementioned sensing region 17a, 17b. The sensing regions 17a, 17b are connected to respective edge regions 18a, 18b via connecting regions 20a, 20b. The two edge regions 18a, 18b of each of the reinforcing elements 13a, 13b lie on one of the main surfaces 11a, 11b of the base body 11. In other words, the first and second edge regions 18a of the first reinforcing element 13a lie on a partial region of the first main surface 11a on the upper side 25 of the base body 11 and thus of the piezoelectric actuator 1. Furthermore, the first and the second edge region 18b of the second reinforcing element 13b lie on a partial region of the second main surface 11b on the underside 26 of the base body 11 and thus of the piezoelectric actuator 1.The edge regions 18a, 18b are preferably permanently connected to the respective main surface 11a, 11b. In particular, the edge regions 18a, 18b are connected to the respective main surface 11a, 11b by an adhesive bond 15. As an alternative to the following description, the reinforcing elements 13a, 13b can be attached to the base body 11 over their entire surface here and in the embodiments described below, for example, by means of an adhesive applied over the entire surface, which can simultaneously act as the dielectric described further below.

[0057] The sensing regions 17a, 17b are spaced apart from the respective main surface 11a, 11b. In particular, a free region 16 is located between the sensing region 17a of the first reinforcing element 13a and the first main surface 11a, as well as between the sensing region 17b of the second reinforcing element 13b and the second main surface 11b. The free regions 16 have a height h which is, for example, greater than or equal to 0.1 mm and less than or equal to 5.0 mm when no voltage is applied to the piezoelectric actuator 1 and no external force acts on the reinforcing elements 13a, 13b.

[0058] Preferably, the sensing regions 17a, 17b are designed such that they run substantially parallel to the main surfaces 11a, 11b. The connecting regions 20a, 20b run obliquely to the main surfaces 11a, 11b. In other words, each of the connecting regions 20a, 20b forms an angle with the main surfaces 11a, 11b. The angle is preferably less than or equal to 45°. Thus, the height h of the free region 16 decreases in the direction from the sensing region 17a, 17b toward the edge regions 18a, 18b of the respective reinforcing element 13a, 13b.

[0059] If an electrical voltage is now applied to the piezoelectric actuator 1, for example by a control device connected to the outer electrodes 23 of the piezoelectric actuator 1, the sensing regions 17a, 17b of the reinforcing elements 13a, 13b move, as described above, relative to the base body 11 in the stroke direction R2, which can be perceived as a haptic signal, for example by a user. In this case, the reinforcing elements 13a, 13b bend preferably at transitions between the sensing regions 17a, 17b and the connecting regions 20a, 20b, as well as between the connecting regions 20a, 20b and the edge regions 18a, 18b. The reinforcing elements 13a, 13b can have at least one thinning, preferably several thinnings, between said areas, which enable better deformability of the reinforcing elements 13a, 13b and easier execution of the lifting movement.Movement of the edge regions 18a, 18b in the stroke direction R2 is prevented by the adhesive connection 15 to the piezoelectric actuator 1. Rather, the edge regions 18a, 18b move with the base body 11 in the longitudinal direction RI. Thus, a relative movement occurs between the edge regions 18a, 18b and the sensing regions 17a, 17b.

[0060] If a force is exerted on the piezoelectric actuator 1 along the stroke movement R2, which can occur, for example, through a haptic input from a user, the reinforcing elements 13a, 13b are deformed such that the sensing regions 17a, 17b are pressed closer to the respective main surface 11a, 11b and the edge regions 18a, 18b are pressed away from one another in the longitudinal direction RI. By attaching the reinforcing elements 13a, 13b to the base body 11 of the piezoelectric actuator 1, the latter is also deformed in the longitudinal direction RI. This generates an electrical voltage in the piezoelectric actuator 1. This voltage can be detected at the external electrodes 23 and in this way it can be inferred that a haptic input has occurred. The piezoelectric actuator 1 can thus be used as a sensor that can detect a force exerted by a user.For this purpose, the piezoelectric actuator 1 can be connected to the outer electrodes 23 with a control device which evaluates the electrical voltages generated at the piezoelectric actuator 1.

[0061] Figures 2A and 2B show a three-dimensional representation and a two-dimensional sectional view of another exemplary embodiment of a piezoelectric actuator 1 for the haptic devices described below. Compared to the previous exemplary embodiment, the actuator 1 has a base body 11 with a square base area and thus with square main surfaces 11a, 11b. For the sake of clarity, the internal electrodes are not shown in the sectional view in Figure 2B.

[0062] The reinforcing elements 13, 13b are each designed as a circular, curved disc, for example based on the shape of a truncated cone or in the manner of a cymbal or a cymbal, which has an edge region 18a which surrounds the sensing region 17a which is spaced from the piezoelectric actuator 1 and which is fastened to the base body 11. For air exchange during a movement of the sensing regions 17a, 17b, these can each have an opening, as indicated in Figures 2A and 2B. The base body 11 and thus the piezoelectric actuator 1 can, for example, have a side length of greater than or equal to 5 mm and less than or equal to 100 mm.

[0063] In the embodiment shown, the external electrodes 23 are applied to the first main surface 11a of the base body 11 and can extend to at least one end face for contacting the internal electrodes.

[0064] Furthermore, the embodiment shown in Figures 2A and 2B may have features like the embodiment shown in Figures 1A and 1B.

[0065] As an alternative to the geometries shown, other geometries for the piezoelectric actuator 1 and the reinforcing elements 13a, 13b are also possible, as described, for example, in the documents WO 2017 / 060 011 A1, WO 2018 / 046 201 A1 and WO 2022 / 248 244 A1, the respective disclosure content of which is incorporated by reference in this regard.

[0066] In conjunction with the figures described below, haptic devices 100 are explained which have a piezoelectric actuator 1, which can be designed according to the previous exemplary embodiments. Furthermore, the haptic devices 100 described below have, purely by way of example, a first reinforcing element 13a in the form of a curved circular disk on the first main surface 11a of the base body 11 of the piezoelectric actuator 1 and a second reinforcing element 13b in the form of a curved circular disk on the second main surface 11b of the base body 11 of the piezoelectric actuator 1, as described in conjunction with Figures 2A and 2B.Alternatively, the haptic devices 100 described below may, for example, also comprise only the first reinforcing element 13a and be free of a reinforcing element on the second main surface 11b and / or have other geometries, for example as described in connection with Figures 1A and 1B. The following description relates primarily to the differences from the exemplary embodiments of the previous figures. Elements and components not described may therefore preferably be designed as explained in connection with Figures 1A to 2B.

[0067] Figure 3A shows an exemplary embodiment of the haptic device 100 in a sectional view as shown in Figure 2B. Figure 3B shows the haptic device in a three-dimensional view without the first reinforcement element 13a in order to provide a clear view of the top side 25 of the piezoelectric actuator 1.

[0068] The haptic device 100 has a first capacitive element 30a. The first capacitive element 30a has, in particular, a first electrode 31a and a second electrode 32a and is designed as a capacitive sensor. The first amplification element 13a forms the first electrode 31a of the first capacitive element 30a. Furthermore, the second electrode 32a of the first capacitive element 30a is arranged on the first main surface 11a of the base body 11 of the piezoelectric actuator 1. Alternatively, the second electrode 32a can also be arranged on the second main surface 11b, wherein the following description applies equally.

[0069] The second electrode 32a is preferably formed by a coating in the form of a single-layer or multi-layer electrode layer on the first main surface 11a. For example, the second electrode 32a can have a first layer with or made of copper and a second layer with or made of silver. Alternatively, the second electrode 32a can be formed, for example, only by a copper layer or only by a silver layer or by one or more layers with or made of other metals. Particularly preferably, all electrically conductive structures applied to the first main surface 11a are identical or similar, so that they can preferably be produced in common work steps, for example by screen printing. This can apply in particular to the electrical contact elements 311a, 321a described further below.

[0070] As indicated in Figure 3A, the second electrode 32a is arranged at least below the sensing region 17a. This can mean that the second electrode 32a is only indicated below the sensing region 17a. Alternatively, the second electrode 32a can also have a greater extent along the main extension direction of the first main surface 11a than the sensing region 17a of the first reinforcing element 13a. As described in connection with the previous figures, the action of a force, for example by a user, on the sensing region 17a of the first reinforcing element 13a can result in the sensing region 17a being pressed in the direction of the first main surface 11a, which then brings about a change in the length of the base body 11 of the piezoelectric actuator 1.In particular, in the haptic device 100, the distance between the first electrode 31a of the first capacitive element 30a, i.e., in particular, the sensing region 17a of the first amplification element 13a, and the second electrode 32a is also reduced, thereby changing the electrical capacitance of the first capacitive element 30a. By detecting the capacitance of the first capacitive element 30a, a distance between the first electrode 31a, i.e., the first amplification element 13a, and the second electrode 32a can be deduced. Since the distance between the first electrode 31a, i.e., the first amplification element 13a, and the second electrode 32a depends on the force acting on the first electrode 31a, i.e., the sensing area 17a of the first amplification element 13a, this force can be deduced by detecting the capacitance of the first capacitive element 30a. Thus, the first capacitive element 30a can be designed as a force sensor.

[0071] The haptic device 100 thus has an integrated first capacitive element 30a, wherein the first reinforcement element 13a has a dual function, namely a mechanical function in cooperation with the piezoelectric actuator 1 and an electrical function in connection with the first capacitive element 30a. For electrically contacting the first capacitive element 30a, the latter has a first electrical contact element 311a, with which the first electrode 31a of the first capacitive element 30a can be electrically contacted from the outside, and a second electrical contact element 321a, with which the second electrode 32a of the first capacitive element 30a can be electrically contacted from the outside. As described above, the first electrical contact element 311a and / or the second electrical contact element 321a can, for example, have a first layer with or made of copper and a second layer with or made of silver.Alternatively, the first electrical contact element 311a and / or the second electrical contact element 321a can be formed, for example, by only a copper layer or only a silver layer or by one or more layers with or made of other metals. In particular, the first electrical contact element 311a and / or the second electrical contact element 321a can be the same as the second electrode 32a in terms of material and layer structure.

[0072] The first electrical contact element 311a for the electrical connection of the first electrode 31a, i.e. the first reinforcement element 13a, has a first connection region 312a and a fastening region 313a on the first main surface 11a. The second electrical contact element 321a for the electrical connection of the second electrode 32a has a second connection region 322a and a conductor track 324a, by means of which the second connection region 322a is electrically conductively connected to the second electrode 32a. The first connection region 312a and the second connection region 322a can particularly preferably be arranged on the first main surface 11a, as can the external electrodes 23. As described above for the second electrode 32a, the first electrical contact element 311a and the second electrical contact element 321a can be formed entirely or partially by an electrically conductive coating on the first main surface 11a.The fastening region 313a of the first electrical contact element 311a is provided and configured such that the first reinforcing element 13a is at least partially arranged and mounted on the first fastening region 313a. By means of the fastening region 313a, the first electrode 31a formed by the first reinforcing element 13a is thus electrically conductively connected to the first connection region 312a. In particular, the edge region 18a of the first reinforcing element 13a is at least partially electrically conductively fastened on the fastening region 313a of the first electrical contact element 311a. In other words, the entire edge region 18a or only a part of the edge region 18a of the first reinforcing element 13a can be arranged and fastened on the fastening region 313a of the first electrical contact element 311a.The fastening region 313a and the first connection region 312a can be directly adjacent to one another or merge into one another or are connected to one another by means of a conductor track 314a on the main surface 11a, as shown.

[0073] As described above in connection with Figures 1A to 2B, the edge region 18a of the first reinforcing element 13a is bonded to the piezoelectric actuator 1 by an adhesive connection 15, i.e., by means of an adhesive. In Figure 3B, the adhesive connection 15, i.e., the region in which the adhesive is arranged, is indicated by the annular region outlined in dashed lines. The adhesive can be an electrically conductive adhesive, i.e., a conductive adhesive, comprising an adhesive polymer filled with electrically conductive particles. Furthermore, the adhesive can be an electrically insulating adhesive which is formed in a layer which is sufficiently thin and, for example, has a thickness of less than or equal to 20 pm, so that an electrically conductive contact is nevertheless created between the edge region 18a of the first reinforcing element 13a and the fastening region 313a of the first electrical contact element 311a.

[0074] In the illustrated embodiment, the edge region 18a of the first reinforcing element 13a is partially secured to the securing region 313a and partially to the first main surface 11a. This may mean, in particular, that the securing region 313a is not provided in the entire region of the first main surface 11a covered by the edge region 18a, but rather that the adhesive is arranged not only between a part of the edge region 18a and the securing region 313a, but also between another part of the edge region 18a and a region of the first main surface 11a not covered by the securing region 313a. For this purpose, the fastening region 313a is formed, for example, as shown in Figure 3B, in a serpentine or meandering manner on the first main surface 11a, so that the edge region 18a of the first reinforcing element 13a and the adhesive connection 15 also cover regions that are free of the material of the fastening region 313a.Such an embodiment can be advantageous, for example, if the adhesive connection 15 has better adhesion to the material of the base body 11 than to the material of the fastening region 313a.

[0075] In the illustrated embodiment, an electrically insulating layer 325a is applied to the conductor track 324a of the second electrical contact element 321a. The electrically insulating layer 325a, for example, a plastic film or a plastic coating, can electrically insulate the conductor track 324a of the second electrical contact element 321a from the first electrode 31a, i.e., the first reinforcement element 13a.

[0076] Modifications of the haptic device 100 are explained in conjunction with the other figures. The following description is therefore essentially limited to differences from previous embodiments.

[0077] As shown in Figure 4 in a further embodiment of the haptic device 100, the first electrical contact element 311a can also be formed by the first connection region 312a on the first main surface 11a and a flexible electrically conductive connecting element 316a, such as, for example, an electrically conductive adhesive tape. As shown, the first connection region 312a can be connected to the upper side of the first reinforcement element 13a facing away from the first main surface 11a or, alternatively, to the underside of the first reinforcement element 13a facing the first main surface 11a.

[0078] As previously indicated in Figures 3A and 3B, the second electrode 32a can be formed by an electrode layer directly on the first main surface 11a of the base body 11. Alternatively, as indicated in a further embodiment of the haptic device 100 in Figure 5A, the electrode layer forming the second electrode can also be applied on a step and thus on a raised area that is formed on the base body. For example, the raised area can have an intermediate layer 40 or be made of it, for example with or made of a plastic material. Alternatively, the raised area can also be formed in the first main surface 11a and thus, for example, by a

[0079] Structuring of the material of the base body 11. Due to the raised region, the second electrode 32a can be arranged closer to the sensing region 17a of the first amplification element 13a and thus closer to the first electrode 31a, which can lead to an amplification of a capacitive signal of the first capacitive element 30a. In particular, a distance between the first electrode 31a and the second electrode 32a of greater than or equal to 50 pm and less than or equal to 200 pm, for example approximately 150 pm, can be advantageous with regard to a good signal from the first capacitive element 30a.

[0080] In the free area 16 between the first reinforcement element 13a, i.e. in particular between the sensing area 17a of the first reinforcement element 13a, and the first main surface 11a, and thus particularly preferably between the first electrode 31a and the second electrode 32a of the first capacitive element 30a, there is a dielectric material, which is for example air. Alternatively, the free area 16 can for example be at least partially filled with a plastic material as dielectric material 50, which can for example be a plastic foam. Furthermore, as indicated in Figure 5B in a further embodiment of the haptic device 100, a plastic film can for example be present as dielectric material 50, which is for example arranged at least on the second electrode 32a.By using a suitably selected dielectric material 50, for example, the capacitance of the first capacitive element 30a and / or electrical insulation between the first electrode 31a and the second electrode 32a can be adjusted. Furthermore, as described above, the dielectric material 50 can be formed by an adhesive applied over the entire surface, by which the entire first reinforcing element 13a can be attached to the base body 11. In this case, the adhesive can provide the distance from the first main surface and simultaneously act as a dielectric.

[0081] Figure 5C shows a further exemplary embodiment of the haptic device 100 which, in comparison to the exemplary embodiments in Figures 3A to 5B, has a second capacitive element 30b. The second capacitive element 30b likewise has a first electrode 31b and a second electrode 32b and is designed as a capacitive sensor. The second reinforcement element 13b forms the first electrode 31b of the second capacitive element 30b. Furthermore, the second electrode 32b of the second capacitive element 30b is arranged on the second main surface 11b of the base body 11. Also visible in Figure 5C is the conductor track 324b of the second electrical contact element of the second capacitive element 30b for contacting the second electrode 32b.

[0082] The first capacitive element 30a and the second capacitive element 30b are particularly preferably designed identically, so that the features and properties of the first capacitive element 30a described in connection with the previous exemplary embodiments can apply correspondingly to the second capacitive element 30b, so that when a force is applied to the haptic device 100, at least substantially identical capacitive signals can be detected at the two capacitive elements 30a, 30b. Alternatively, the first capacitive element 30a and the second capacitive element 30b can be designed differently, so that when a force is applied to the haptic device 100, different capacitive signals can be detected at the two capacitive elements 30a, 30b.In the embodiments described above and below, the haptic device 100 may also have a second capacitive element 30b, which may be designed the same as the first capacitive element 30a or differently therefrom.

[0083] For example, the edge region of the first reinforcing element can be fastened exclusively to the fastening region. In this case, as indicated in Figure 6A in a representation of the haptic device 100 without the first reinforcing element 13a, the region of the first main surface 11a covered by the edge region of the first reinforcing element can be completely provided with the fastening region 313a of the first electrical contact element 311a. This can accordingly be designed, for example, as a circumferential ring.

[0084] Furthermore, as indicated in Figure 6A and in a section of a sectional view in Figure 6B, the second electrical contact element 321a can have at least one electrical via 327a or, as shown, two electrical vias 327a and a conductor track 324a arranged within the base body 11, through which the second electrode 32a is connected to the second connection region 322a of the second electrical contact element 321a. As a result, the conductor track 324a of the second electrical contact element 321a can be electrically insulated from the fastening region 313a of the first electrical contact element 311a and from the first reinforcement element by the material of the base body 11 of the piezoelectric actuator 1.

[0085] As shown in Figures 7A and 7B in views corresponding to Figures 6A and 6B, the second electrode 32a can be formed by an electrode layer within the base body 11 of the piezoelectric actuator 1. In this case, the second electrode 32a is arranged within the base body 11 below the first main surface. Particularly preferably, the second electrical contact element 321a has at least one electrical via 327a, through which the second electrode 32a is connected to the second connection region 322a. In the exemplary embodiment shown, the electrode layer forming the second electrode 32a is different from the internal electrodes of the piezoelectric actuator 1 and is thus electrically insulated from them by the piezoelectric material of the base body 11.

[0086] Furthermore, as indicated in Figures 8A and 8B in views also corresponding to Figures 6A and 6B, the second electrode 32 can be formed by at least one internal electrode 21 of the piezoelectric actuator 1. In this case, said at least one internal electrode 21 has a dual function, namely an electrical function in connection with the piezoelectric actuator 1 and an electrical function in connection with the first capacitive element 30a. Furthermore, the second connection region 322a or even the second electrical contact element 321a of the first capacitive element 30a can simultaneously be an external electrode 23 for internal electrodes 21 of the piezoelectric actuator 1. In the embodiments described above, the first reinforcement element 13a has in particular a sensing region 17a which has a constant wall thickness and a flat shape.As indicated in Figures 9A to 11B, the first reinforcement element 13a, which in Figures 9A to 11B is contacted purely by way of example as described in connection with Figure 4, can have at least one raised region 170a in the touch region 17a on an underside facing the first main surface 11a, that is to say a region extending towards the first main surface 11a, as a result of which the effective distance between the first electrode 31a and the second electrode 32a of the first capacitive element 30a can be influenced.In particular, a distance between the first electrode 31a of the first capacitive element 30a, formed by the first reinforcement element 13a, and the second electrode 32a of the first capacitive element 30a can be reduced as described above in connection with Figure 5A, whereby a stronger capacitive field can be generated and thus the capacitive signal and in particular the signal-to-noise ratio of the first capacitive element 30a can be increased. For example, the at least one raised region 170a can be formed by an embossed structure introduced from an upper side of the first reinforcement element 13a facing away from the first main surface 11a. In other words, the at least one raised region 170a on the underside can correspond to a recessed region on the upper side of the touch region 17a, which has been introduced by embossing from the upper side of the touch region 17a.The second reinforcing element 13b can have a corresponding tactile region 17b with at least one raised region 170b. As indicated in Figures 9A and 9B, the raised region 170a on the underside of the first reinforcing element 13a can be, for example, annular and can have, for example, two raised rings extending toward the first main surface 11a. On the upper side of the first reinforcing element 13a facing away from the first main surface 11a, two annular depressions are correspondingly embossed, as can be seen in Figure 9A.

[0087] As indicated in Figures 10A and 10B in representations of the first reinforcing element 13a, the raised region 170a on the underside can, for example, also be formed by only an annular region that corresponds to a corresponding annular embossed depression in the upper side. Instead of an impression, the first reinforcing element 13a in the tactile region 17a can, for example, also have a thickening, i.e., a region with a greater thickness that extends to the first main surface, to form the raised region 170a, as indicated in Figure 10C.

[0088] The raised region is not limited to ring shapes. As indicated in Figures 11A and 11B, a spoke-like structure can also be embossed, for example, which in the illustrated embodiment results in four corresponding raised regions 170a on the underside of the tactile region 17a of the first reinforcing element 13a.

[0089] By arranging the external electrodes and the connection areas of the electrical contact elements on the same side of the haptic device 100, for example, on the first main surface of the piezoelectric actuator, simple electrical contacting of the haptic device 100 is possible. For example, this can be achieved using a flexible printed circuit connector (FPC connector) 60, as shown in Figure 12.

[0090] The haptic device described here uses capacitive field sensing to cost-effectively integrate a static force sensor into a piezoelectric actuator. By integrating a static force sensor into the actuator component, the typical touch sensing requirements of, in particular, sophisticated, haptic user interfaces can be met. By using a single component as sensor and actuator, new systems can be created that can reduce costs, weight, and design complexity. The sensing function of the piezoelectric actuator itself can also be supported or improved by using the capacitive element, for example as a safety function, for example with regard to the signal-to-noise ratio, the response time, and / or a force-time measurement, with the field sensor, and vice versa.

[0091] As described above, the force measurement solution is realized by arranging two conductive surfaces in the form of the first and second electrodes of at least the first capacitive element so close to each other that a capacitive field can be generated. The capacitance of the generated field changes when the distance between the two electrodes changes. So, for example, when a user presses a touch surface with a finger, which in turn presses the haptic device, the two electrodes of at least the first capacitive element move closer together, and the force with which the finger presses can be determined, regardless of the speed at which the touch force occurs.A touch input can then be triggered at exactly the right time and, if desired, the same haptic device can also generate haptic feedback to confirm that the input has been registered.

[0092] The haptic device enables reliable force sensing combined with haptic feedback in a single component, which can reduce costs and design complexity. For example, haptic feedback is often based on small mechanical movements in the range of greater than or equal to 10 and less than or equal to 300 pm. Consequently, high mechanical tolerances are required during system integration. Using a separate force sensor and a separate haptic actuator would not only be complex in terms of system integration, but also very demanding and expensive in terms of mechanics and assembly.

[0093] A further advantage of the haptic device described here is its multiple sensor functionality, which can be useful, for example, from a safety and energy-saving perspective. For example, safety-critical switches, such as the hazard warning switch found in every car, may require two input circuits. By integrating two capacitive elements, i.e. the first and second capacitive elements, on either side of the piezoelectric actuator, these can be redundantly integrated into two similar circuits. In other applications, it may be sufficient to use the piezoelectric actuator as a piezoelectric sensor in one circuit and the first capacitive element as a capacitive field sensor in the other circuit.Furthermore, with regard to energy savings, it can be noted that generating a capacitive field always consumes energy, especially if you want to generate a field and measure the change. While a lower sensor frequency can be used, this still consumes energy if delays are introduced into the system. Piezoelectric sensors are passive sensors that generate a voltage when pressed. Therefore, it may be possible to use the piezoelectric actuator to "wake up" the capacitive element and then still measure the change, as well as longer-lasting pressure with the capacitive element to detect the force and duration of the pressure. Human movements are typically so slow that a reaction time of a few milliseconds may be fast enough to detect a capacitive change.

[0094] The features and exemplary embodiments described in conjunction with the figures can be combined with one another according to further exemplary embodiments, even if not all combinations are explicitly described. Furthermore, the exemplary embodiments described in conjunction with the figures can alternatively or additionally comprise further features according to the description in the general part.

[0095] The invention is not limited to the embodiments described herein. Rather, the invention encompasses any novel feature and any combination of features, including, in particular, any combination of features in the claims, even if this feature or combination itself is not explicitly stated in the claims or embodiments.

[0096] Reference symbol list piezoelectric actuator

[0097] 11 Basic body

[0098] 11a, 11b Main surface

[0099] 12 I isolation area

[0100] 13a, 13b Reinforcing element

[0101] 15 Adhesive bond

[0102] 16 outdoor area

[0103] 17a, 17b Touch area

[0104] 18a, 18b edge area

[0105] 20a, 20b connection area

[0106] 21 Internal electrode

[0107] 22 piezoelectric layer

[0108] 23 Outer electrode

[0109] 24 Frontal area

[0110] 25 Top

[0111] 26 Bottom

[0112] 30a, 30b capacitive element

[0113] 31a, 31b first electrode

[0114] 32a, 32b second electrode

[0115] 40 Intermediate layer

[0116] 50 dielectric material

[0117] 60 connectors

[0118] 100 haptic device

[0119] 170a, 170b raised area

[0120] 311a, 321a electrical contact element

[0121] 312a, 322a connection area

[0122] 313a fastening area

[0123] 314a conductor track

[0124] 316a electrically conductive connecting element

[0125] 324a, 324b conductor track

[0126] 325a electrically insulating layer

[0127] 327a electrical via

[0128] B Width

[0129] H Height L Length

[0130] RI longitudinal direction

[0131] R2 stroke direction

[0132] S Stacking direction

Claims

Patent claims 1. Haptic device (100) comprising - a piezoelectric actuator (1) having a Base body (11) and - a first reinforcing element (13a) on a first Main surface (11a) of the piezoelectric actuator (1), - a first capacitive element (30a), wherein the first amplifying element (13a) is attached to the piezoelectric actuator (1) and has a sensing region (17a) arranged at a distance above the first main surface (11a), wherein the first reinforcing element (13a) has a first Electrode (31a) of the first capacitive element (30a), wherein a second electrode (32a) of the first capacitive element (30a) is arranged on a main surface (11a, 11b) or within the base body (11).

2. Haptic device (100) according to claim 1, wherein the first reinforcing element (13a) is attached to the piezoelectric actuator (1) at least by an edge region (18a).

3. Haptic device (100) according to claim 1 or 2, wherein the first reinforcing element (13a) is attached to the piezoelectric actuator (1) over its entire surface.

4. Haptic device (100) according to claim 2, further comprising a first electrical contact element (311a) for electrically contacting the first electrode (31a).

5. Haptic device (100) according to claim 4, wherein the first electrical contact element (311a) has a first connection region (312a) and a fastening region (313a) on the first main surface (11a).

6. Haptic device (100) according to claim 5, wherein the edge region (18a) of the first reinforcing element (13a) is at least partially electrically conductively fastened to the fastening region (313a) of the first electrical contact element (311a).

7. Haptic device (100) according to claim 5 or 6, wherein the edge region (18a) is glued to the fastening region (313a) by means of an adhesive connection (15) formed by an electrically conductive adhesive.

8. Haptic device (100) according to claim 5 or 6, wherein the edge region (18a) is glued to the fastening region (313a) by means of an adhesive connection (15) formed by an electrically insulating adhesive.

7. Haptic device (100) according to one of claims 5 to 8, wherein the edge region (18a) is partially attached to the attachment region (313a) and partially directly to the first main surface (11a).

8. Haptic device (100) according to claim 7, wherein the fastening region (313a) is serpentine or meandering on the first main surface (11a).

9. Haptic device (100) according to one of the preceding claims, wherein the touch region (17a) has at least one raised region (170a) on a bottom side facing the first main surface (11a), which extends towards the first main surface (11a).

10. Haptic device (100) according to claim 9, wherein the at least one raised region (170a) is formed by an embossed structure introduced from an upper side of the first reinforcing element (13a) facing away from the first main surface (11a).

11. Haptic device (100) according to claim 9, wherein the at least one raised region (170a) is formed by a thickening of the tactile region (17a).

12. Haptic device (100) according to one of the preceding claims, wherein the second electrode (32a) is arranged on the first main surface (11a) or below the first main surface (11a) within the main body (11) of the first capacitive element (30a).

13. Haptic device (100) according to one of the preceding claims, wherein the second electrode (32a) is arranged only below the tactile region (17a).

14. Haptic device (100) according to one of the preceding claims, further comprising a second electrical contact element (321a) with a second connection area (322a) for electrically contacting the second electrode (32a).

15. Haptic device (100) according to one of the preceding claims, wherein the second electrode (32a) is formed by an electrode layer on a main surface (11a, 11b).

16. Haptic device (100) according to claim 14 and 15, wherein the second electrical contact element (321a) has a conductive track (324a) on a main surface (11a) through which the second electrode (32a) is connected to the second connection region (322a).

17. Haptic device (100) according to claim 16, wherein an electrically insulating layer (325a) is applied to the conductor track (324a).

18. Haptic device (100) according to claim 14 and 15, wherein the second electrical contact element (321a) has at least one electrical via (327a) and a conductor track (324a) arranged within the base body (11), by means of which the second electrode (32a) is connected to the second connection region (322a).

19. Haptic device (100) according to one of claims 1 to 14, wherein the second electrode (32a) is formed by an electrode layer within the base body (11).

20. Haptic device (100) according to claim 14 and 19, wherein the second electrical contact element (321a) has at least one electrical via (327a) through which the second electrode (32a) is connected to the second connection region (322a).

21. Haptic device (100) according to one of claims 1 to 14, wherein the second electrode (32a) is formed by at least one internal electrode (21) of the piezoelectric actuator (1).

22. Haptic device (100) according to one of the preceding claims, wherein a dielectric material (50) comprising one or more of: air, plastic film, plastic foam, adhesive is arranged between the tactile region (17a) of the first reinforcing element (13a) and the first main surface (11).

23. Haptic device (100) according to one of the preceding claims, further comprising: - a second reinforcing element (13b) on a second Main surface (11b) of the piezoelectric actuator (1), - a second capacitive element (30b), wherein the second amplification element (13b) is fastened to the piezoelectric actuator (1) and has a sensing region (17b) which is arranged at a distance above the second main surface (11b), wherein the second amplification element (13b) forms a first electrode (31b) of the second capacitive element (30b), wherein a second electrode (32b) of the second capacitive element (30b) is arranged on a main surface (11b) or within the base body (11).

24. Haptic device (100) according to one of the preceding claims, wherein the haptic device (100) is designed to generate haptic feedback.

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