Haptic device

Abstract

The invention relates to a haptic device (100) which has a piezoelectric actuator (1) comprising a main body (10) and at least one reinforcing element (30) on a first main surface (11) of the piezoelectric actuator (1), the at least one reinforcing element (30) having at least one fastening region (39) via which the at least one reinforcing element (30) is fastened to the main body (10), and a lifting region (31) which is arranged at a distance from and above the first main surface (11), and a connecting layer (20) being arranged between the at least one fastening region (39) and the first main surface (11).

Description

[0001] Description

[0002] Haptic device

[0003] A haptic device is specified. Such a device has an actuator that can generate and / or detect a movement. For example, the haptic device can be coupled to a movable element, which can be designed, for example, as a touch-sensitive surface or the 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). Furthermore, the haptic device can be used in the automotive sector.

[0005] Devices for generating haptic feedback are known from the publications WO 2017 / 032 868 A1, WO 2018 / 046 201 A1, WO 2020 / 011 403 A1, and WO 2021 / 019 083 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. Reliable attachment of the reinforcement element is of particular importance here.

[0006] At least one object of certain embodiments is to provide a haptic device. 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.

[0007] 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.

[0008] The haptic device particularly preferably comprises 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. In the following, the term "piezoelectric actuator" can also refer to the base body, and vice versa.

[0009] 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. if 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 the internal electrodes.

[0010] The base body, and thus the piezoelectric actuator, can preferably be cuboid-shaped and have a longitudinal direction. For example, the longitudinal direction can correspond to a direction with the greatest extent of the base body. If the base body is constructed in a multilayer design, the longitudinal direction can preferably be perpendicular to the stacking direction.

[0011] By applying a suitable electrical signal, the piezoelectric actuator can undergo a change in its expansion in at least one direction, whereby this change can be part of the haptic signal. Applying an alternating voltage can generate a periodic change and thus a vibration. In particular, the change in the expansion of the piezoelectric actuator can be caused at least by the d31 effect and correspond at least to a change in the length of the piezoelectric actuator along the longitudinal direction. Conversely, a mechanical action caused by a haptic input can cause a change in the expansion of the base body in at least one direction, particularly preferably the longitudinal direction. Due to the inverse piezoelectric effect, this change in expansion can generate an electrical voltage in the piezoelectric material, which can be detected, for example, via the internal electrodes.

[0012] 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.

[0013] According to a further embodiment, the haptic device has at least one mechanical reinforcement element, which is referred to below for short as at least one reinforcement element. The at least one reinforcement element is fastened to the piezoelectric actuator. In particular, the at least one 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 at least one reinforcement element and thus at least regions of the first reinforcement element are moved. Particularly preferably, the at least one reinforcement element can be fastened to the piezoelectric actuator in such a way that a change in the length of the piezoelectric actuator and in particular of the base body at least along its longitudinal direction moves a region of the at least one reinforcement element in a direction perpendicular to the longitudinal direction.Furthermore, a direction is also possible that forms an angle with the longitudinal direction that is greater than 0° and less than 90°. In other words, a region of the at least one reinforcing element can be moved in a direction oblique to the longitudinal direction.

[0014] 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 each have a main direction of extension which runs parallel to the longitudinal direction. The arrangement direction from the first main surface to the second main surface, which in the case of a base body with a multi-layer construction can preferably coincide with the stacking direction, is particularly preferably perpendicular to the longitudinal direction. The at least one reinforcing element can preferably be applied and fastened to one of the main surfaces. Without being intended to be restrictive, it is assumed in the following that if the haptic device has only one reinforcing element, this is arranged on the first main surface of the base body.The base body may further comprise side surfaces that connect the first and second main surfaces to one another. In particular, the base body may comprise two opposing longitudinal side surfaces. Furthermore, the base body may comprise two opposing end surfaces. The longitudinal side surfaces extend along the longitudinal direction, while the end surfaces are preferably oriented perpendicular to the longitudinal direction.

[0015] The at least one reinforcing element can have a first mechanical reinforcing element, which is referred to below as the first reinforcing element and which is applied and fastened on the first main surface of the base body and thus on the first main surface of the piezoelectric actuator. Furthermore, the at least one reinforcing element can have at least one second mechanical reinforcing element, which is referred to below as the second reinforcing element and which is applied and fastened on the second main surface of the base body and thus on the second main surface of the piezoelectric actuator. Thus, the haptic device can particularly preferably have the piezoelectric actuator which is arranged between the first and second reinforcing element.

[0016] The following description is essentially limited to the at least one reinforcement element mentioned above and applies to the first reinforcement element and, if present in the haptic device, correspondingly also to the second reinforcement element. The features and properties described above and below for the at least one reinforcement element can therefore apply correspondingly to the first reinforcement element and, if present in the haptic device, to the second reinforcement element. 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. If the haptic device has more than two reinforcement elements, the described features and embodiments apply accordingly.

[0017] The at least one reinforcing element can comprise or be made of metal, for example steel and / or titanium. For example, the at least one reinforcing element can be plate-shaped. Furthermore, the at least one reinforcing element can be flat, i.e. as a planar plate, which is fastened to the piezoelectric actuator by at least one fastening region, which can be, for example, an edge region or an intermediate region, or even over its entire surface. Particularly preferably, the at least one reinforcing element can be a metal bracket, i.e. a metal strip or a metal sheet with a non-planar geometry.The at least one reinforcing element can, for example, be fastened to one or two end regions or to two end regions and an intermediate region of a main surface of the base body along the longitudinal direction of the piezoelectric actuator by means of at least one or preferably at least two fastening regions, which can preferably be edge regions or also edge regions and at least one intermediate region of the at least one reinforcing element along the longitudinal direction. Adjacent to the one fastening region or between the at least two fastening regions, it has at least one stroke region spaced apart from the piezoelectric actuator. Thus, the at least one reinforcing element can preferably have at least one fastening region, with which the at least one reinforcing element is fastened to the base body, and a stroke region which is arranged at a distance above the corresponding main surface.If the at least one reinforcement element has more than one fastening region, these regions, as well as the manner of the respective fastening, are particularly preferably of identical design. The features and embodiments described below in connection with at least one fastening region can thus apply equally to all fastening regions of the at least one reinforcement element.

[0018] According to a further embodiment, a connecting layer is arranged between the at least one fastening region and the first main surface. The fastening of the at least one fastening region to the base body and thus to the piezoelectric actuator can thus particularly preferably be carried out by the connecting layer. The connecting layer can particularly preferably comprise an adhesive or be an adhesive layer. Thus, the term "connecting layer" can also refer to the material of the connecting layer, for example an adhesive. The at least one reinforcing element can thus preferably be fastened to the piezoelectric actuator by an adhesive bond.If at least one reinforcement element is made of or with 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 only minimal or no mechanical stresses occur during temperature changes, so that the adhesive bond is subjected to little or no mechanical stress during temperature changes. Furthermore, the bonding layer can also be or comprise, for example, a solder layer, a weld layer, or a silver sintered layer.

[0019] For example, a dielectric material can be arranged between the stroke region of the at least one reinforcing element and the main surface on which the at least one reinforcing element is arranged and fastened. The dielectric material can, for example, comprise one or more materials selected from air, plastic film, and plastic foam.

[0020] As already described above, the at least one 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.Reinforcement can therefore be achieved by combining the piezoelectric actuator with the at least one reinforcing element. The at least one reinforcing element can be free of notches and have a constant wall thickness. By omitting notches in the at least one reinforcing element, simple production of the at least one reinforcing element can be enabled. Furthermore, the at least one reinforcing element can have at least one notch which reduces mechanical resistance to deformation of the at least one 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 expedient, since the notches can facilitate deformation of the reinforcing element.The notches can be created, for example, by processes such as milling, punching and / or embossing.

[0021] According to a further embodiment, the haptic device has at least one fastening improvement element which is provided and configured to increase the reliability of the fastening of the at least one fastening region to the base body. Particularly preferably, the at least one fastening improvement element can be provided and configured to increase the durability of the fastening of the at least one fastening region to the piezoelectric actuator, which fastening is mediated by the connecting layer. Due to the previously described deformation of the piezoelectric actuator and the at least one reinforcing element, forces such as shear forces can occur in the region of the connecting layer, which can promote detachment of the at least one fastening region from the piezoelectric actuator.This can be particularly the case in harsh conditions such as increased humidity and / or increased temperature, as this can weaken the bonding layer. The at least one fastening improvement element can be provided and designed to counteract such detachment effects. The embodiments and features for the at least one fastening improvement element described below can be present individually or in combination. If the at least one reinforcing element has a plurality of fastening regions, these can each have one or more identical or different fastening improvement elements. Accordingly, the embodiments and features for the at least one fastening improvement element described below apply equally to all fastening regions of the haptic device.

[0022] According to a further embodiment, the at least one fastening-enhancing element is part of the at least one reinforcing element. In other words, the fastening-enhancing element can have or be a structure in or on the at least one reinforcing element that is intended and configured, for example, to counteract the previously described detachment effect promoted by shear forces.

[0023] For example, the at least one fastening improvement element can have a surface structure on a fastening surface of the at least one fastening region facing the base body and thus the piezoelectric actuator, in which at least a part of the connecting layer is arranged.

[0024] Surface structure can, for example, have at least one

[0025] have or be a depression. By at least one

[0026] A depression, which can form a pocket in the form of a wedge-shaped recess in the fastening surface, can for example make it possible to locally increase the amount of material in the connecting layer and thus achieve a locally greater thickness of the connecting layer. The depression can particularly preferably be formed on an edge of the at least one fastening region facing the lifting region. There can be a particularly high tendency to detach at the edge of the fastening region facing the lifting region, which tendency can be counteracted by the locally greater thickness of the connecting layer. Furthermore, the fastening improvement element can have a surface-enlarging structure as a surface structure, in which at least part of the connecting layer is arranged. The surface-enlarging structure can have, for example, grooves or slots, such as longitudinal grooves or transverse grooves.The surface-enlarging structure can increase the interface between the fastening surface and the bonding layer, thereby increasing the fastening effect of the bonding layer.

[0027] Furthermore, the at least one fastening improvement element can have at least one wing element adjacent to the fastening region, wherein the wing element extends at least partially along a side surface of the base body adjacent to the first main surface, particularly preferably a longitudinal side surface. The wing element can be formed integrally with the fastening region and, for example, form a type of tab or clamp that covers or encloses part of the side surface. Furthermore, the at least one fastening improvement element can have two wing elements that extend at least partially along two opposite side surfaces of the base body, particularly preferably the two longitudinal side surfaces. The at least one wing element can particularly preferably be aligned at right angles to the fastening surface.

[0028] The connecting layer can additionally be arranged not only between the fastening surface and the main surface of the base body, but also between the at least one wing element and the base body. In other words, the at least one wing element can cause an enlargement of the interface between the at least one reinforcing element and the base body. Furthermore, by arranging the wing element on a side surface of the base body, support and a different force dissipation can take place compared to the fastening region, whereby detachment effects can be counteracted. The at least one wing element can therefore achieve an improved and defined force distribution and increased rigidity of the fastening region.Furthermore, as described above, which form the above-described first and second reinforcement element, wherein the connecting layer is additionally arranged between the at least one wing element of the at least one reinforcement element and at least the fastening region and / or a wing element of the further reinforcement element. In other words, the two reinforcement elements can be fastened to one another by the connecting layer between the respective wing elements and / or fastening regions, as a result of which detachment effects can be counteracted. Accordingly, the at least one wing element of the at least one reinforcement element can be fastened with a part of the connecting layer to the base body and / or to the fastening region and / or to a wing element of a further reinforcement element.Furthermore, the at least one wing element of the at least one reinforcing element can have a toothing structure which is provided and designed to engage in a complementary toothing structure of a wing element or of a fastening region of a further reinforcing element. In this case, the connecting layer can preferably also be arranged between the toothing structures of the two reinforcing elements. The toothing structures can be formed, for example, by the wing element, or a part thereof, of one reinforcing element being arranged longitudinally next to the wing element, or a part thereof, of the other reinforcing element.

[0029] According to a further embodiment, the fastening-improving element comprises a region of the at least one reinforcing element or is such a region that protrudes beyond the base body on a side facing away from the stroke region. In other words, the at least one reinforcing element can protrude beyond the base body on a side facing away from the stroke region. This makes it possible to protect an end region of the piezoelectric actuator, i.e., in particular, edge protection, preferably along the longitudinal direction.

[0030] According to a further embodiment, the

[0031] The fastening improvement element comprises a covering of the at least one fastening region of the at least one reinforcing element with the connecting layer. In other words, the fastening region can be covered with the material of the connecting layer. In particular, the connecting layer can form a cap over the base body and the reinforcing element in the fastening region, so that the fastening region, together with a region of the base body, is covered in the connecting layer.

[0032] According to a further embodiment, the at least one fastening improvement element has a prepreg between the first main surface and the fastening region of the at least one reinforcing element and in particular the fastening surface, which prepreg is filled with the material of the connecting layer. A prepreg can in particular be a flat, for example planar, textile semi-finished product pre-impregnated with a thermoplastic or thermosetting matrix, which has one or more unidirectional layers with or made of threads or a woven fabric or a laid fabric with preferably perpendicularly arranged threads. A prepreg can, for example, be a base material for a printed circuit board and can preferably have a glass fiber fabric impregnated with an epoxy adhesive. By using one or more such layers, the thickness of the connecting layer can be adjusted and thus optimized.

[0033] According to a further embodiment, the fastening improvement element comprises an element which is present in addition to the at least one reinforcing element. This ensures that no significant changes are made to the at least one reinforcing element compared to a haptic device without

[0034] Fixing improvement element must be made.

[0035] For example, the at least one fastening improvement element can have a clamping device which is pushed onto the at least one reinforcing element and the base body in the at least one fastening region of the at least one reinforcing element. The clamping device is particularly preferably clamp-shaped, ring-shaped or cap-shaped. In other words, the clamping device can be a clamp element, a ring element or a cap element. The clamping device can enclose the at least one fastening region and a part of the base body of the piezoelectric actuator in such a way that a tendency towards detachment can be counteracted.

[0036] According to a further embodiment, the fastening improvement element has a conformal coating which envelops the haptic device. A conformal coating is particularly referred to as a coating which, unlike, for example, a volume potting, covers the surfaces of the haptic device with a substantially uniform, thin layer. The functionality of the covered elements is preferably not hindered by the conformal coating and the original contour is substantially retained. The conformal coating can have a thickness of greater than or equal to 1 μm and less than or equal to 5 mm or less than or equal to 1 mm or less than or equal to 100 μm and in particular can comprise or be made of a plastic material, for example based on a silicone or acrylate.The conformal coating, which preferably covers all exposed surface areas, or all exposed surface areas except for the outer electrodes, can protect the at least one connecting layer from damaging external influences such as moisture, which could lead to degeneration of the at least one connecting layer and thus to a deterioration in the attachment of the at least one reinforcing element. The conformal coating can be applied, for example, by dip coating, spray coating, or brush coating.

[0037] According to a further embodiment, the haptic device has a side surface adjacent to the first main surface of the base body, on which side surface at least two external electrodes are arranged for electrically contacting the haptic device. In particular, the at least two external electrodes can be provided and configured for electrically controlling the base body and thus the piezoelectric actuator. The at least two external electrodes can particularly preferably be the only external electrodes of the piezoelectric actuator and can all be arranged on the same longitudinal side surface.A flexible connection element, for example a so-called flexible printed circuit (FPC) or a cable, in particular a multi-pole cable such as a two-pole cable, can be connected to the at least two external electrodes on the base body. The cable can have connection points, for example solder contacts or a plug, on a side facing away from the base body. If the haptic device has a conformal coating as described above, this can particularly preferably envelop a part of the flexible connection element together with the piezoelectric actuator. According to a further embodiment, the piezoelectric actuator has at least one passive region in the base body, i.e. a region which does not participate in changes in length of the piezoelectric actuator. The at least one passive region can preferably border on the at least one fastening region.The at least one fastening improvement element can have the passive region or be formed thereby. For example, the base body can have internal electrodes and the passive region can be a region of the base body that is free of any internal electrodes. Accordingly, the piezoelectric actuator in the base body can have a plurality of internal electrode layers and the fastening improvement element can have a region of the base body in the at least one fastening region that borders on the at least one fastening region and is free of internal electrode layers. By having at least one passive region bordering on the at least one fastening region, a change in the length of the piezoelectric actuator in the at least one fastening region can be avoided, as a result of which stress forces that could act on the connecting layer can be reduced or prevented.

[0038] As previously stated, the haptic device described here can preferably incorporate measures that can improve the manufacturability and / or service life of the haptic device. Particularly advantageous features and properties are summarized again below.

[0039] As described, the outer electrodes can be used instead of the

[0040] End faces are applied to the same long side surface. This can reduce the manufacturing effort for the metallization of the external electrodes by 50%, since both external electrodes can be applied in the form of contact pads in one step without having to rotate the base body. Another advantage is the possibility of using a flexible connection element such as an FCP for the electrical connection. Compared to soldered wires, this has the advantage of being easier to process in mass production, thinner and lighter, and easier to handle during assembly with a special FPC connector.

[0041] Furthermore, as described, one or more fastening improvement elements can be provided which improve the connection between the reinforcing elements and the piezoelectric actuator, whereby the detachment forces can be increased.

[0042] For example, at least one reinforcing element can be designed so that one or more wing elements are present which are bent over corners of the piezoelectric actuator. This can be particularly advantageous when using liquid adhesive as the material for the connecting layers. With this construction it can also be possible to connect the two separate reinforcing elements to one another by means of the connecting layers, i.e. preferably by gluing. This can have the advantage that some of the detachment forces and splitting forces acting on the connecting layers cancel each other out. Furthermore, the stiffness of the connecting layers can be increased compared to a flat design of the fastening areas. Increased stiffness reduces the detachment forces acting on the reinforcing elements, which can represent a critical type of load on the inside of a fastening area.

[0043] Furthermore, the design with the wing elements, in particular, makes it possible to apply the material for the bonding layers comprehensively around the entire component in the area of ​​the fastening zones. This can reduce the likelihood of areas with poor bonding layer coverage and lead to a uniform force distribution within the bonding layers.

[0044] Furthermore, to improve the mechanical connection between the reinforcement element and the base body, at least one clamping device in the form of a bracket, a clamp, a ring, or a cap can be provided, which is preferably made of or with metal, for example aluminum, stainless steel, or titanium, and which preferably has a similar functionality to the wing elements. In addition to being bonded to the piezoelectric actuator, the clamping device can be designed such that it presses the reinforcement element(s) against the base body and holds the position, for example, only through friction, for example via a conical internal structure.

[0045] Furthermore, the attachment areas of the reinforcing elements can be modified to form grooves or slots. This shape can lead to an increased amount of material for the bonding layers in general and to an increased amount in contact with the surface of a reinforcing element in order to strengthen the bond and to ensure a more even force distribution. In order to increase the amount of material for the bonding layer in the critical area on the inside of the attachment areas, a recess, for example with a wedge-like shape, can be incorporated into the reinforcing element. Furthermore, prepregs can be applied between the base body and the reinforcing elements and filled with adhesive for the bonding layers in order to achieve an even material distribution in the attachment areas.

[0046] Furthermore, the base body can be designed in such a way that passive areas are created in the area of ​​the fastening areas in order to reduce the shear forces that would arise from the contraction and expansion of the piezoelectric actuator at these points.

[0047] The design with wing elements or clamp devices can also protect the piezoelectric actuator from shocks and mechanical contact, as it is comprehensively covered by the material of the connecting layers and reinforcing elements, which are preferably made of metal. This protective function is not limited to a specific variant of the reinforcing elements and can be applied to any shape. Furthermore, the reinforcing elements can be designed to be flush with the base body, which can also protect the piezoelectric actuator from shocks or impacts.

[0048] To increase the durability of the bonding layers under harsh conditions, a conformal coating can be provided as protection. In particular, the coating is applied to protect the bonding layers from damage and failure. Before the coating process, the edges of the base body can be rounded. This has the advantage that the layer thickness is very uniform across the entire component. This uniformity is beneficial to ensure reliable protection against high humidity. In addition to the rounded edges, the viscosity of the coating material itself, for example a resin, is also advantageously matched to the piezoelectric actuator in order to further improve the wettability of the component edges.

[0049] Further advantages, advantageous embodiments and further developments emerge from the exemplary embodiments described below in conjunction with the figures.

[0050] Figures 1A and 1B show schematic representations of a haptic device according to an embodiment,

[0051] Figures 2A and 2B show schematic representations of a haptic device according to further embodiments, Figures 3A to 3C show schematic representations of a haptic device according to a further embodiment,

[0052] Figure 4 shows a schematic representation of a part of a haptic device according to a further embodiment,

[0053] Figures 5A to 5C show schematic representations of a haptic device according to a further embodiment,

[0054] Figures 6A to 6C show schematic representations of a

[0055] Haptic device according to another

[0056] Embodiment , Figures 7A to 7G show schematic representations of a haptic device according to another embodiment , Figures 8A and 8B show schematic representations of a haptic device according to another embodiment ,

[0057] Figures 9A to 9C show schematic representations of a haptic device according to a further embodiment,

[0058] Figures 10A to 10C show schematic representations of a haptic device according to a further embodiment,

[0059] Figures 11A to 11C show schematic representations of a haptic device according to a further embodiment,

[0060] Figures 12A to 12C show schematic representations of a haptic device according to a further embodiment,

[0061] Figures 13 to 15 show schematic representations of a haptic device according to further embodiments, Figures 16A to 18C show schematic representations of a haptic device according to a further embodiment,

[0062] Figures 19A to 22B show schematic representations of a haptic device according to further embodiments.

[0063] In the embodiments and figures, identical, similar or similarly acting elements can each be provided with the same reference numerals. The elements shown and their relative sizes to one another are not to be regarded as being to scale; rather, individual elements, such as layers, components, structural elements and regions, can be shown exaggeratedly large for clarity and / or better understanding. The features and embodiments described in connection with the figures can be combined with one another according to further embodiments, even if not all combinations are described explicitly. Furthermore, the embodiments described in connection with the figures can alternatively or additionally have further features in accordance with the description in the general part.

[0064] Figures 1A and 1B show an exemplary embodiment of a haptic device 100 with a piezoelectric actuator 1 with reinforcing elements 30 in a perspective view and in a sectional view. The geometries of the piezoelectric actuator 1 shown in Figures 1A and 1B and of the reinforcing elements 30 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 30. Deviations from the exemplary embodiment shown, for example with regard to geometric configurations, are not excluded by the following description. Furthermore, in the exemplary embodiment shown and also in the exemplary embodiments described below, for example, only one reinforcing element 30 can be present.

[0065] The piezoelectric actuator 1 has a base body 10 with a first main surface 11 and a second main surface 12, on each of which one of the reinforcing elements 30 is arranged. The base body 10 has a stack of internal electrodes 13 and piezoelectric layers 14 stacked alternately on top of one another in a stacking direction S, which are electrically contacted by the internal electrodes 13. The internal electrodes 13 can be electrically contacted from the outside via external electrodes 15 on a surface of the base body 10. Even if a plurality of internal electrodes 13 is shown in Figure 1B, the base body 10 can also have, for example, only one or two or a different number of internal electrodes 13. Furthermore, the base body 10 can also be free of internal electrodes, so that the base body 10 can be designed as a monolithic disk or plate that is free of internal electrodes.In this case, electrical contact is made exclusively via the external electrodes 15 .

[0066] The base body 10 is preferably cuboid-shaped with an elongated form, as shown, and has a longitudinal direction with a length L that corresponds to the main direction of extension of the base body 10. Perpendicular to the longitudinal direction, the base body 10 has a width direction with a width B. Perpendicular to the longitudinal direction, the base body 10 ends with end faces 16. Along the width direction, the base body 10 ends with longitudinal side faces 17 that are oriented perpendicular to the width direction. The end faces 16 and the longitudinal side faces 17 form the side faces of the base body 10. In the height direction, which is perpendicular to the longitudinal direction and perpendicular to the width direction, the base body 10 has a height H and ends with an upper side 18, which forms the first main surface 11, and a lower side 19, which forms the second main surface 12, which are perpendicular to the height direction.The height direction preferably corresponds to the stacking direction S . As an alternative to the cuboid shape shown, the base body 10 can also have other shapes, wherein preferably at least the top side 18 and the bottom side 19 are parallel to each other.

[0067] A first reinforcing element 30 is arranged on the first main surface 11 of the base body 10 and thus of the piezoelectric actuator 1, and the second of the reinforcing elements 30 is arranged on the second main surface 12 of the base body 10 and thus of the piezoelectric actuator 1, said second main surface being opposite the first main surface 11 along the stacking direction S. Even though two reinforcing elements 30 are always shown here and below, it may also be possible for, for example, only the first reinforcing element 30 to be present on the first main surface 11. The reinforcing elements 30 have fastening regions 39 with which the reinforcing elements 30 are fastened to the respective main surface 11, 12.

[0068] As described above, the piezoelectric actuator 1 furthermore has two external electrodes 15 which are provided for external electrical contacting of the base body 10 and thus of the piezoelectric actuator 1. The external electrodes 15 are, as shown in Figure 1A, preferably applied to one of the longitudinal side surfaces 17 of the base body 10. The internal electrodes 13 are alternately contacted with one of the external electrodes 15 in the stacking direction S. The external electrodes 15 are applied in the form of one or more metal layers, preferably by means of sputtering, screen printing, dip coating or another suitable method. By arranging the external electrodes 15 next to one another on the same longitudinal side surface 17, this can preferably be carried out in a common process step.

[0069] The piezoelectric layers 14 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 14 can have a

[0070] Pb (Zr x Ti!- x ) O3 + y Pb (Mn! / 3Nb2 / 3 ) O3 . As an alternative to a piezoelectric ceramic material, a piezoelectric polymer, for example, can also be used. The internal electrodes 13 and also the external electrodes 15 preferably comprise copper or consist of copper or an alloy with copper.

[0071] The base body 10 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 height H of the piezoelectric actuator 10 can, for example, be greater than or equal to 300 pm and less than or equal to 3 mm.

[0072] The piezoelectric actuator 1 is designed such that when an electrical voltage is applied to the outer electrodes 15 and thus also to the inner electrodes 13, a deformation of the base body 10 takes place, in particular in the multi-layer construction shown with the inner electrodes 13 a change in length in the direction of change RI indicated in Figure 1B. In particular, the piezoelectric layers 14 are therefore polarized such that the application of an electrical voltage between the inner electrodes 13 leads to a contraction of the base body 10, in which the length L of the base body 10 changes perpendicular to the stacking direction S. Consequently, an expansion of the base body 10 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 expansion changes can also be achieved by other configurations with or without internal electrodes in the base body 10.For the sake of clarity, the following description refers, without being restrictive, to the multi-layer design shown with the described change in length.

[0073] In order to redirect the effect of the change in length in the stacking direction S, the reinforcing elements 30 are provided. If a voltage is applied to the piezoelectric actuator 1, the reinforcing elements 30 deform at least partially as a result of the change in the extension of the base body 10. In particular, the reinforcing elements 30 are dimensioned and connected to the base body 10 of the piezoelectric actuator 1 in such a way that a stroke region 31 of the reinforcing elements 30, as a result of a change in the length L of the base body 10, each stroke region 31 of the reinforcing elements 30 carries out a stroke movement in the stroke direction R2 indicated in Figure 1B, corresponding to the stacking direction S, wherein the amplitude of the stroke movement can preferably be greater than the amplitude of the change in the length L of the piezoelectric actuator 1.

[0074] The piezoelectric actuator 1 is, as shown, preferably arranged between the reinforcing elements 30. Each of the reinforcing elements 30 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 30 is curved or bent and is bow-shaped. Alternatively, a flat design of the reinforcing elements 30 is also possible. For example, the reinforcing elements 30 each have a sheet metal strip or are made thereof, in particular with or from steel and / or titanium.

[0075] Each of the reinforcing elements 30 is preferably subdivided into a plurality of regions or sections. Thus, in addition to the lifting region 31, each reinforcing element 30 has edge regions 32 which are connected to the respective lifting region 31 via transition regions 33. The two edge regions 32 of each of the reinforcing elements 30 lie on one of the main surfaces 11, 12 of the base body 10. The edge regions 32 are preferably non-detachably connected to the respective main surface 11, 12, so that in the exemplary embodiment shown, the edge regions 32 of the reinforcing elements 30 are the fastening regions 39 of the reinforcing elements 30. In particular, each of the fastening regions 39 is connected to the respective main surface 11, 12 by a connecting layer 20, which is indicated in Figure 1B.Even if the connecting layers 20 are not shown in Figure 1A and in the figures described below, a connecting layer is always arranged between a fastening region 39 and the piezoelectric actuator 1.

[0076] The connecting layer 20 can particularly preferably be formed by an adhesive, for example an epoxy, so that the reinforcing elements 30 are preferably connected to the base body 10 and thus to the piezoelectric actuator by adhesive bonds. Furthermore, a solder layer or microsilver or a weld layer are also possible for the connecting layers 20.

[0077] The stroke regions 31 are spaced apart from the respective main surface 11, 12. In particular, a free region 38 is located between the stroke region 31 of each of the reinforcing elements 30 and the respective main surface 11. The free regions 38 have a height that 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 30.

[0078] Preferably, the lifting regions 31 are designed such that they run substantially parallel to the main surfaces 11, 12. The transition regions 33 run obliquely to the main surfaces 11, 12. In other words, each of the transition regions 33 forms an angle with the main surfaces 11, 12. The angle is preferably less than or equal to 45°. Thus, the height of the free region 38 decreases in the direction from the lifting region 31 toward the edge regions 32 and thus toward the fastening regions 39 of the respective reinforcing element 30.

[0079] If an electrical voltage is now applied to the piezoelectric actuator 1, for example by a control device connected to the outer electrodes 15 of the piezoelectric actuator 1, the stroke regions 31 of the reinforcement elements 30 move relative to the base body 10 in the stroke direction R2, as described above, which can be perceived as a haptic signal, for example by a user. The reinforcement elements 30 bend preferably at transitions between the stroke regions 31 and the transition regions 33 and between the transition regions 33 and the edge regions 32. A movement of the edge regions 32 in the stroke direction R2 is prevented by the attachment by means of the connecting layers 20 on the piezoelectric actuator 1. Instead, the edge regions 32 move with the base body 10 in the longitudinal direction RI. A relative movement therefore takes place between the edge regions 32 and the stroke regions 31.

[0080] 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 30 are deformed such that the stroke regions 31 are pressed closer to the respective main surface 11, 12 and the edge regions 32 are pressed away from one another in the longitudinal direction RI. By fastening the reinforcing elements 30 to the base body 10 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 outer electrodes 15 and in this way inferences can be drawn as to a haptic input. 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 15 with a control device which evaluates the electrical voltages generated at the piezoelectric actuator 1.

[0081] In conjunction with the figures described below, modifications and further developments of the haptic device 100 according to the previous exemplary embodiment are shown. The following description is therefore essentially limited to differences from the previous exemplary embodiments. For the sake of clarity, it may be possible that not all elements and components are shown in the figures described below, or that they are shown but not provided with reference symbols and are not explained. Elements and components not shown or not marked in a figure can, for example, be designed according to the description of previous or subsequent exemplary embodiments.

[0082] As shown in Figure 2A in a further exemplary embodiment of a haptic device 100 with the piezoelectric actuator 1 and the reinforcing elements 30, the reinforcing elements 30 can have thinned sections 34 between said regions, which enable better deformability of the reinforcing elements 30 and easier execution of the lifting movement described above. Furthermore, openings 35 can be present in the lifting region 31 of the reinforcing elements 30, which openings 35 enable, for example, a mechanical connection of the reinforcing elements 30 to other components, for example by rivet or screw connections. As shown in the following figures, the lifting region 31 can, for example, also have connecting plates or be connected to connecting plates, by means of which the haptic device 100 can be mounted to other components.

[0083] Figure 2B shows a further exemplary embodiment of the haptic device 100, which has a flexible connection element 40, for example a so-called flexible printed circuit (FPC), which is connected to the two external electrodes. For example, the connection element 40 can be soldered to the external electrodes on the long side surface. By electrically connecting the piezoelectric actuator 1 via the connection element 40 on the long side surface, a reduction in process steps can be achieved, for example in the production of the external contacts on the base body. The external electrodes in the case of elongated piezoceramic components are usually located on the two end faces of the base body. Such positioning of electrical contacts leads to increased expenditure in large-scale production and limits the possibilities for electrical connection.For example, FPC connections are then very difficult or even impossible to realize. By placing the external electrodes next to one another on a single long side surface of the piezoelectric actuator 1, the production effort can be essentially halved because both external electrodes can be applied in a common process step. Furthermore, the piezoelectric actuator 1 can be connected via a connection element 40 formed by an FPC, as described, which can reduce the overall space required for system integration of the haptic device 100 and simplify handling. This can also reduce production effort, particularly in large-scale production, because the connection process for connecting the connection element 40 takes place on only one side of the piezoelectric actuator 1.In addition, processes such as ref low soldering, laser soldering, hotbar soldering or the use of anisotropic conductive adhesive (ACF: "anisotropic conductive film") can only be used effectively with the described geometry.

[0084] As described above, the reinforcing elements 30 are fastened to the piezoelectric actuator 1 by means of the connecting layers 20 with the respective fastening regions 39. With this type of construction, there is a risk of delamination of the reinforcing elements 30 if the haptic device is operated under harsh conditions, i.e. at elevated temperatures and / or in an atmosphere with high humidity and / or other damaging substances. During operation, the deformations of the piezoelectric actuator 1 and the reinforcing elements 30 described above cause, among other things, shear forces to act on the connecting layers 20, which, as described, can comprise or consist of an adhesive, for example. Most adhesives available on the market have reduced shear strength under harsh conditions, particularly at elevated temperatures.If the applied shear force exceeds the shear strength of the adhesive, this can result in the bond layers delaminating over time. Typically, an initial crack develops at the edge of the bond layer and propagates until the affected attachment area is completely delaminated.

[0085] As simulations have shown, delamination is mainly promoted by two factors. The first factor is the shrinkage and expansion of the ceramic material of the base body, which can occur below a fastening area 39 during operation. The second factor is a force that acts perpendicular to the bonding layer 20 during operation as a result of the reinforcing movement of a reinforcing element 30. The simulations have shown that during operation the expected shear stress on a bonding layer promoted by both factors can be equal to or higher than the shear strength of most adhesives on the market. In addition, the shear strength of adhesives is temperature-dependent, so that an increase in temperature can lead to a decrease in shear strength.For most adhesives, the shear strength at elevated temperatures is below the shear stress typically experienced during service, as determined by simulations. Prolonged service can lead to a crack in the bond layer at the interface with the attachment region of a reinforcement element. Once such a crack has occurred, any further service promotes crack growth along the contact surface of the bond layer with the reinforcement element until the attachment region delaminates. Crack propagation is primarily caused by the second factor described above.

[0086] To promote the reliability of the attachment of the reinforcement elements 30 to the attachment areas 39 on the piezoelectric actuator 1, the haptic device 1 further comprises at least one attachment improvement element. The exemplary embodiments described below for the at least one attachment improvement element can also be provided in the previous exemplary embodiments. Furthermore, the exemplary embodiments for the at least one attachment improvement element can also be combined, so that a plurality of the described attachment improvement elements can be provided in the haptic device 100.

[0087] In particular, the at least one fastening-enhancing element 50 can be part of a reinforcing element 30 or of both reinforcing elements 30. In particular, the at least one fastening-enhancing element 50 can have or be a structure in or on at least one reinforcing element that is provided and configured, for example, to counteract the previously described detachment effect promoted by shear forces.

[0088] Figure 3A shows an exemplary embodiment of a haptic device 100 with fastening enhancement elements 50. Figure 3B shows the two reinforcement elements 30 of the haptic device 100, and Figure 3C shows only one of the reinforcement elements 30.

[0089] The reinforcing elements 30 each have a fastening improvement element 50 in each fastening region 39. The fastening improvement elements 50 are each formed on a fastening surface 390 of each of the fastening regions 39 facing the base body and thus the piezoelectric actuator 1 and are formed by a surface structure in which a part of the connecting layer is arranged. In the exemplary embodiment shown, the respective surface structure has at least one depression 51 or is formed as such. By means of the respective depression 51, which can form, for example, a pocket in the form of a wedge-shaped depression in the fastening surface 390, a local increase in the amount of material of the connecting layer and thus a locally greater thickness of the connecting layer can be achieved.Particularly preferably, the recesses 51 are each formed on an edge of the edge regions 32 designed as fastening regions 39 facing the lifting region 31. At the edge of an edge region 32 facing the lifting region 31, there may be a particularly high tendency to detach, which can be counteracted by the locally greater thickness of the connecting layer.

[0090] Furthermore, in the described and following embodiments, the thickness of the connecting layers 20 can be increased by applying prepregs 21 in order to precisely define the thickness, as indicated in Figure 4. A prepreg 21 can, as described in the general section, be a basic element of a printed circuit board and comprise a glass fiber fabric impregnated with an epoxy adhesive. A specific thickness of the connecting layers 20 can be set by using several fabric layers, which are then filled with an adhesive 22.

[0091] Figures 5A to 5C show, in views corresponding to the views in Figures 4A to 4G, a further exemplary embodiment in which the fastening improvement elements 50 have, as a surface structure, a surface-enlarging structure 52 in which at least part of the connecting layer is arranged. The surface-enlarging structure 52 is in the form of grooves or slots, such as longitudinal grooves or, as shown, transverse grooves. The respective surface-enlarging structure 52 can increase the interface between the fastening surfaces 390 and the respective connecting layer, whereby the fastening effect of the connecting layers can be increased.

[0092] The described fastening improvement elements 50 formed as surface structures in the fastening surfaces 390 can form measures for reducing the occurrence of cracks, in particular by increasing the thickness of the connecting layer on the inner edge of the fastening regions 39, i.e. the edge facing the respective lifting region 31. By increasing the thickness of the connecting layers in said regions, the acting shear stress can be distributed over a larger volume of the material of the connecting layers and thus the maximum shear stress in the fastening regions 39 can be reduced. In both embodiments shown, the fastening regions 39 are thus each divided into two regions, namely an outer region facing away from the respective lifting region 31 and an inner region facing the respective lifting region 31.According to the embodiment of Figures 3A to 3C, the respective outer region has a thinner part of the connecting layer, which reinforces the overall connection between reinforcing element 30 and piezoelectric actuator 1, while the respective inner region contains a thicker part of the connecting layer in order to distribute the shear stress. According to the embodiment of Figures 5A to 5C, the respective inner region is preferably reduced to half the sheet thickness and grooves or slots are preferably formed perpendicular to the longitudinal direction of the haptic device 100. This increases the thickness of the connecting layer and the area of ​​the respective fastening region 39 that interacts with the connecting layer.

[0093] Figures 6A to 6C show, in views corresponding to the views in Figures 4A to 4G, a further exemplary embodiment in which the fastening improvement elements 50 each have at least one wing element 53 adjacent to the fastening regions 39, wherein each of the wing elements 53 extends at least partially along a side surface of the piezoelectric actuator 1 adjacent to the main surfaces, in the exemplary embodiment shown a longitudinal side surface. The wing elements 53 are formed integrally with the respective fastening region 39 and each form a type of tab or clamp that covers or encloses part of the side surface.

[0094] For each of the fastening improvement elements 50 designed as wing elements 53, the connecting layer is preferably arranged not only between the fastening surface 390 and the corresponding main surface of the piezoelectric actuator 1, but additionally also between the wing element 53 and the piezoelectric actuator 1. As a result, the wing elements 53 can increase the adhesion surfaces between the reinforcing elements 30 and the piezoelectric actuator 1. Furthermore, by arranging a wing element 53 on a side surface of the base body of the piezoelectric actuator 1, support and a different force dissipation can be achieved compared to the fastening region 39, whereby detachment effects can be counteracted.Furthermore, the respective connecting layer can additionally be arranged between a wing element 53 of one of the reinforcing elements 30 and the fastening region 39 and / or the wing element 53 of the other reinforcing element 30, so that the two reinforcing elements 30 are fastened to one another by the connecting layer between the respective wing elements 53 and / or fastening regions 39.

[0095] Figures 7A to 7C show, in views corresponding to the views in Figures 4A to 4C, a further exemplary embodiment in which the fastening improvement elements 50 designed as wing elements 53 further comprise a toothed structure 54 which is provided and configured to engage in a complementary toothed structure 54 of a wing element 53 or of a fastening region 39 of the respective other reinforcing element 30. Figure 7D shows a section of the haptic device 100. Figure 7E shows a view along the longitudinal direction of the haptic device 100. The connecting layer is preferably additionally arranged between the toothed structures 54 of the two reinforcing elements 30.

[0096] Furthermore, the reinforcing elements 30 at the stroke regions 31 in the illustrated embodiment have, purely by way of example, connecting plates 31' for mounting the haptic device 100. Each of the connecting plates 31' borders on the respective stroke region 31 and extends away from it. The connecting plates 31' preferably extend along the width direction away from the piezoelectric actuator 1 and from the respective stroke region 31 and thus preferably enclose an angle of 90° or substantially 90° with the longitudinal side surfaces of the piezoelectric actuator 1 and the stroke regions 31. In the transition between the lifting regions 31 running parallel to the longitudinal side surfaces and the connecting plates 31 ', the reinforcement elements 30 shown each have a reinforcement region 31 '', in particular a reinforcement region 31 '' bent by an angle of 180 ° or substantially 180 °.By bending through 180° or substantially 180°, it is possible to divert the force of the lifting movement centrally onto the fastening regions 39, as can be seen in Figure 7E, whereby twisting and torsion of the reinforcing elements 30 can be avoided or at least reduced. Furthermore, as indicated in Figures 7F and 7G, the connecting plate 31' can be fastened to the respective lifting region 31 by means of at least one connecting element 37. The at least one connecting element 37 can, for example, have a weld or an adhesive bond and can be designed as one or more weld points, weld seams, adhesive points and / or adhesive seams.Both by means of the connecting elements 37 between the stroke regions 31 and the connecting plates 31 ', such as welding points or adhesive points, as indicated in Figure 7F, or a welding seam or adhesive seam, as indicated in Figure 7G, and by means of the reinforcing regions 31 ', it may be possible to increase the rigidity of the reinforcing elements 30 in order to be able to transmit the energy with only minimal losses. This may lead to increased haptic feedback. The exemplary embodiments described below may also have connecting plates or connecting plates and reinforcing regions, which, however, are not provided with reference symbols for the sake of clarity.

[0097] Figures 8A and 8B show a further exemplary embodiment in which, in comparison to the exemplary embodiment in Figures 7A to 7D, the reinforcing elements 30 project beyond the piezoelectric actuator 1 in the longitudinal direction. The illustration in Figure 8A shows the haptic device 100 corresponding to the illustration in Figure 7A, whereas in Figure 8B the piezoelectric actuator 1 is shown with only one of the connecting elements 30. Because the reinforcing elements 30 project beyond the piezoelectric actuator 1 in the longitudinal direction, protection for the edges in the region of the end faces 16 can be achieved. In contrast to the previous variant, the projecting areas do not form a positive-locking clamp with the piezoelectric actuator 1, but rather result in a projection in the longitudinal direction. This projection can be used as strain relief for possible electrical connections such as the flexible connection element described above.The enclosed areas can be filled with the material of the connecting layers, so that the end faces 16 of the piezoelectric actuator 1 can be covered with the material of the connecting layers and protected against incorrect operation.

[0098] In Figures 9A to 9C, in views corresponding to the views of Figures 4A to 4C, a further exemplary embodiment is shown, in which each of the fastening regions 39 of the reinforcing elements 30 has, as fastening improvement elements 50, two wing elements 53 with toothed structures 54 which extend at least partially along two opposite longitudinal side surfaces of the piezoelectric actuator 1.

[0099] Furthermore, each of the reinforcing elements 30 has, adjacent to the stroke region 31, a stabilization region 31' ' ' which extends from the stroke region 31 to the piezoelectric actuator 1. In particular, the stabilization region 31' ' ' can be formed by a bend, i.e. by an extension of the stroke region 31 along a direction perpendicular to the longitudinal direction of the piezoelectric actuator 1, which is preferably bent by 90° or substantially 90° towards the piezoelectric actuator 1. The stabilization region 31' ' ' stiffens the stroke region 1. In Figures 10A to 10C, in views corresponding to the views in Figures 4A to 4C, a further embodiment is shown in which the fastening improvement elements 50 designed as wing elements 53 extend partially over the end faces of the piezoelectric actuator 1 in comparison to the previous embodiments.

[0100] The wing elements 53 described in connection with Figures 6A to 11C have, among other things, the functionality of clamps which partially encompass the piezoelectric actuator 1 and which can preferably form an interlocking clamp-like structure by means of toothed structures 54 on each side of the fastening regions 39. In particular, the fastening regions 39 with the wing elements 53 can form closed structures which are filled or even enveloped with the material of the connecting layers. In a preferred variant, as shown in Figures 7A to 9C, the wing elements 53 with the toothed structures 54 are mirror-inverted to one another. When the haptic device 100 is fully assembled, the fastening regions 39 with the wing elements 53 completely enclose the piezoelectric actuator 1 in the fastening regions 39.

[0101] Figures 11A to 11C, 12A to 12C and 13 show further exemplary embodiments of the haptic device 100, which have elements in the form of clamping devices 55 as fastening improvement elements 50, which, compared to the previous exemplary embodiments, are present in addition to the reinforcing elements 30. The views of Figures 11A and 12A as well as Figures 11B and 12B correspond to the view of Figure 4A and the view of Figure 4B, respectively, while Figures 11C and 12C each show a clamping device 55. The clamping devices 55 are pushed into the fastening regions 39 of the reinforcing elements 30 onto the reinforcing elements 30 and the piezoelectric actuator 1. Particularly preferably, the clamping devices 55 are ring-shaped, as shown in Figures 11A to 11C, or cap-shaped, as shown in Figures 12A to 12C.Accordingly, the clamping devices can preferably be designed as ring elements or as cap elements.

[0102] In order to prevent the growth of cracks in the connecting layers, forces acting perpendicular to the connecting layers can be counteracted by using the clamping devices 55. The fastening areas 39 are clamped by the clamping devices 55, so that movement of the fastening areas 39 to the main surfaces of the piezoelectric actuator 1 in the perpendicular direction is prevented. In addition, a separate adhesive or the material of the connecting layers can be applied to fix the position of the clamping devices 55 on the fastening areas 39. This also makes it possible to compensate for any tolerances of the reinforcing elements 30, so that perfect clamping during operation is guaranteed.

[0103] Alternatively or additionally, the clamping devices 55 can be conically shaped, as indicated in Figure 13 in a sectional view of a part of the haptic device 100 using a clamping device 55 designed as a cap element, wherein in this exemplary embodiment the reinforcing elements 30 additionally have depressions 51 for the connecting layers 20 as fastening improvement elements 50, as described in connection with Figures 4A to 4C. Due to its shape, the clamping device 55 can be fixed by frictional forces. However, the application of an additional filler adhesive in the clamping device 55 can be used as an additional safety measure for reliability.

[0104] Figure 14, which corresponds to the view in Figure 1B, shows a further exemplary embodiment of the haptic device 100, in which the fastening improvement element 50 has passive regions 56 in the piezoelectric actuator 1, i.e. regions that do not participate in changes in length of the piezoelectric actuator 1. As described above, one of the main causes of the shear stress in the fastening regions 39 with the connecting layers 20 is the shrinkage and expansion of the region of the piezoelectric actuator 1 below the fastening regions 39. The passive regions 56 are therefore arranged in the region of the fastening regions 39 in the exemplary embodiment shown and preferably border on the fastening regions 39. As shown in Figure 14, the passive regions 56 are those regions of the base body 10 that are free of any internal electrodes 13.As a result, the regions of the main surfaces 11, 12 that are in contact with the connecting layers 20 are passive areas that do not experience any change in length. Simulations have shown that the shear stress on the fastening regions 39 during operation can be significantly reduced in this way. In particular, it was shown that the shear stress falls below the shear strength of most adhesives available on the market, which still applies to at least some adhesives even at elevated temperatures, so that the selection of possible materials for the connecting layer 20 is greater. Particularly preferably, the fastening improvement elements 50 designed as passive regions 56 can be combined with the clamping devices 55 according to the exemplary embodiments in Figures 11A to 13.

[0105] Figure 15 shows a sectional view of a section of a further exemplary embodiment of the haptic device 100, which has a conformal coating 57 as the fastening improvement element 50, which coating envelops at least the connecting layers 20 and the fastening regions 39 and particularly preferably the entire haptic device 100. The conformal coating 57 covers the surfaces of the haptic device 100 with a substantially uniform, thin layer and comprises or is made of a plastic material, for example based on a silicone or acrylate.By means of the conformal coating 57, which preferably covers all free surface areas or at least all free surface areas except for external electrodes, the connecting layers 20 can be protected from damaging external influences such as moisture, which could lead to degeneration of the connecting layers 20 and thus to a deterioration in the fastening of the reinforcing elements 30. In particular at high air humidity of, for example, 85% RH or more and high temperatures of, for example, 85 °C or more, an increased degradation of the adhesion properties of the connecting layers 20 can occur during operation of the haptic device 100, which can considerably reduce the service life. This effect can be counteracted by the conformal coating 57 as a fastening improvement element 50.

[0106] To produce the conformal coating 57, in a first step the base body 10 of the piezoelectric actuator 1 can be manufactured such that all edges are rounded. Rounding the edges improves the coverability of the edges with coating materials. In general, the problem of poor edge coverage during coating is due to a high surface tension of the component to be coated and an inappropriate viscosity of the coating material. Therefore, the viscosity of the coating material for the conformal coating 57 is further adjusted such that optimal coverage of the entire surface is achieved. This ensures that the rounded edges of the base body 10 are enveloped by the coating material in the following step, so that no diffusion paths for moisture to and into the connecting layers 20 are formed.A closed coating 57 is therefore particularly advantageous for enabling reliable function of the haptic device 100. In a further step, the piezoelectric actuator 1 with the attached reinforcement elements 30 is coated with the coating material to form the conformal coating 57. This can be done, for example, by methods such as spray coating, brush application, and dip coating.

[0107] The haptic device 100 is not limited to the geometries of the previous embodiments. The haptic device 100 can, for example, also be designed according to one of the designs shown in Figures 16A to 18C. In particular, the embodiments shown in Figures 16A to 18C can comprise at least one or more fastening enhancement elements according to one or more of the previous embodiments.

[0108] As shown in Figures 16A and 16B in a three-dimensional view and in a sectional view, the reinforcing elements 30 can be flush with the end faces 16 of the piezoelectric actuator 1 along the longitudinal direction or even protrude beyond the end faces 16. This allows the piezoelectric actuator 1 to be protected against impacts and shocks at the end faces 16.

[0109] 17A to 17C show, in views corresponding to the views in FIGS. 4A to 4C, a further exemplary embodiment in which the reinforcing elements 30 each have a plurality of stroke regions 31 and thus a plurality of haptically active regions, between which an intermediate region 36 is provided which, in addition to the edge regions 32, forms a fastening region 39 of the respective reinforcing element 30. The features described for the fastening regions 39 formed by edge regions 32 according to the previous exemplary embodiments also apply to the intermediate regions 36. Particularly preferably, the piezoelectric actuator 1 can also have a passive region as a fastening improvement element in the region of the outer electrodes 15, which is adjacent to the intermediate regions 36 of the reinforcing elements 30.

[0110] Furthermore, as shown in Figures 18A to 18C in views corresponding to the views of Figures 4A to 4C, the lifting region 31 of the reinforcing elements 30 can, for example, also directly adjoin an edge region 32 without a transition region being present between the lifting region 31 and the relevant edge region 32.

[0111] 19A and 19B show, in views corresponding to the views in FIGS. 7A and 7C, a further exemplary embodiment in which the reinforcing elements 30 each comprise, as fastening improvement elements 50, combinations of the exemplary embodiments in FIGS. 7A to 9C and the exemplary embodiment in FIGS. 10A to 10C. In particular, the reinforcing elements 30 have three wing elements 53 on each fastening region 39, two of which extend at least partially along two opposite longitudinal side surfaces of the base body of the piezoelectric actuator 1 and a further of which extends at least partially along an end face. In particular, a wing element 53 of a reinforcing element 30 extends completely over an end face.

[0112] In Figures 20A to 20C, in views corresponding to the views of Figures 8A, 8B and 7C, a further embodiment is shown which is a combination of the previous embodiment and the embodiment of Figures 9A to 9C, in which the reinforcing elements 30, in addition to the embodiment according to the previous embodiment, each have a stabilization region 31 ' ' ' adjacent to the stroke region 31, which stabilization region extends from the stroke region 31 to the piezoelectric actuator 1.7A and a sectional view of this view, a further exemplary embodiment is shown. This embodiment represents a modification of the previous exemplary embodiment and in which the connecting plate 31' of each of the reinforcing elements 30 is designed as a separate part which is fastened to the respective lifting region 31 by means of the connecting elements 37 described above, for example by welding or gluing. In other words, the connecting plate 31' of each of the reinforcing elements 30 is a separately manufactured part which is fastened to the respective lifting region 31 by means of at least one connecting element 37. Each of the reinforcing elements 30 is thus a two-part component in which a connecting plate 31' is preferably arranged vertically on the respective lifting region 31 and is fastened in a material-to-material manner by welding or gluing.

[0113] 2B, connection options are shown by way of example for the exemplary embodiment of FIGS. 20A to 20C using a flexible connection element 40, as described above in connection with FIG. 2B. The flexible connection element 40, as in the exemplary embodiment of FIG. 2B, can be a flexible printed circuit board which, as shown in FIG. 22A, can be arranged between wing elements 53 of the reinforcing elements 30 and the base body of the piezoelectric actuator 1. For example, the flexible connection element 40 can be clamped by the wing elements 53 and / or glued under the wing elements 53. This can provide strain relief for the connection points between the flexible connection element 40 and the piezoelectric actuator 1.Alternatively, the connection element 40 may not be arranged between the wing elements 53 and the base body, but may run freely along the long side surface, as in the exemplary embodiment in Figure 2B. As indicated in Figure 22B, the flexible connection element 40 may also be a multi-pole cable, for example with a plug. In this case too, the connection element 40 may be arranged between at least one wing element 53 and the base body, as described in connection with Figure 22A. The invention is not limited to the exemplary embodiments by the description thereof. Rather, the invention encompasses any new feature and any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination itself is not explicitly stated in the patent claims or exemplary embodiments.

[0114] Reference symbol list

[0115] 1 piezoelectric actuator

[0116] 10 basic bodies

[0117] 11 , 12 Main interface

[0118] 13 Internal electrode

[0119] 14 piezoelectric layer

[0120] 15 Outer electrode

[0121] 16 Front side surface

[0122] 17 Longitudinal side surface

[0123] 18 Top

[0124] 19 Bottom

[0125] 20 connecting layer

[0126] 21 Prepreg

[0127] 22 Adhesive

[0128] 30 Reinforcing element

[0129] 31 lifting range

[0130] 31 ' connecting plate

[0131] 31 ' gain range

[0132] 31 ' ' stabilization area

[0133] 32 Marginal area

[0134] 33 Transitional area

[0135] 34 Thinning

[0136] 35 Opening

[0137] 36 Intermediate area

[0138] 37 Connecting element

[0139] 38 outdoor area

[0140] 39 Mounting area

[0141] 390 mounting area

[0142] 40 connecting element

[0143] 50 Fastening Improvement Element

[0144] 51 Deepening

[0145] 52 surface-enlarging structure

[0146] 53 wing element

[0147] 54 Gear structure

[0148] 55 Clamping device

[0149] 56 passive area 57 coating

[0150] 100 haptic device

[0151] B Width

[0152] H Height L Length

[0153] RI direction of length change

[0154] R2 stroke direction

[0155] S Stacking direction

Claims

Patent claims 1. Haptic device (100) comprising - a piezoelectric actuator (1) having a Base body (10) and - at least one reinforcing element (30) on a first Main surface (11) of the piezoelectric actuator (1), wherein the at least one reinforcing element (30) has at least one fastening region (39) with which the at least one reinforcing element (30) is fastened to the base body (10), and a lifting region (31) which is arranged at a distance above the first main surface (11), wherein a connecting layer (20) is arranged between the at least one fastening region (39) and the first main surface (11).

2. Haptic device (100) according to claim 1, wherein the at least one fastening region (39) of the at least one reinforcing element (30) is an edge region (32) or an intermediate region (36) of the at least one reinforcing element (30).

3. Haptic device (100) according to claim 1 or 2, wherein the haptic device (100) comprises at least one Fastening improvement element (50) which is intended to increase the reliability of the fastening of the at least one fastening region (39) to the base body (10).

4. Haptic device (100) according to claim 3, wherein the at least one fastening improvement element (50) is part of the at least one reinforcement element (30).

5. Haptic device (100) according to claim 4, wherein the at least one fastening improvement element (50) has a recess (51) on a fastening surface (390) of the at least one fastening region (39) facing the piezoelectric actuator (1), in which recess at least a part of the connecting layer (20) is arranged.

6. Haptic device (100) according to claim 5, wherein the recess (51) is formed on an edge of the at least one fastening region (39) facing the lifting region (31).

7. Haptic device (100) according to one of claims 4 to 6, wherein the at least one fastening improvement element (50) has a surface-enlarging structure (52), in particular grooves, on a fastening surface (390) facing the piezoelectric actuator (1), in which at least part of the connecting layer (20) is arranged.

8. Haptic device (100) according to one of claims 4 to 7, wherein the at least one fastening improvement element (50) has at least one wing element (53) adjacent to the fastening region (39) which extends at least partially along a side surface (16, 17) of the base body (10) adjacent to the first main surface (11).

9. Haptic device (100) according to claim 8, wherein the at least one fastening improvement element (50) has two wing elements (53) which extend at least partially along two opposite longitudinal side surfaces (17) of the base body (10).

10. Haptic device (100) according to claim 8 or 9, wherein the at least one fastening improvement element (50) has two wing elements (53), one of which extends at least partially along a longitudinal side surface (17) of the base body (10) and another of which extends at least partially along an end surface (16).

11. Haptic device (100) according to one of claims 8 to 10, wherein the at least one fastening improvement element (50) has three wing elements (53), two of which extend at least partially along two opposite longitudinal side surfaces (17) of the base body (10) and a further of which extends at least partially along an end surface (16) which adjoins the two opposite side surfaces (17).

12. Haptic device (100) according to one of claims 8 to 11, wherein the at least one wing element (53) is fastened with a part of the connecting layer (20) to the base body (10) and / or to a further reinforcing element (30).

13. Haptic device (100) according to one of claims 8 to 12, wherein the at least one wing element (53) has a toothing structure (54) which is designed to engage in a complementary toothing structure (54) of a further reinforcing element (30).

14. Haptic device (100) according to one of claims 3 to 13, wherein the at least one fastening improvement element (50) comprises a prepreg (21) between the first main surface (11) and the fastening region (39) of the at least one reinforcing element (30).

15. Haptic device (100) according to one of claims 3 to 14, wherein the at least one fastening improvement element (50) has a clamping device (55) which is pushed onto the at least one reinforcement element (30) and the base body (10) in the fastening region (39) of the at least one reinforcement element (30).

16. Haptic device (100) according to one of claims 3 to 15, wherein the at least one fastening improvement element (50) has at least one passive region (57) in the piezoelectric actuator (1) which is adjacent to the at least one fastening region (39).

17. Haptic device (100) according to one of claims 3 to 16, wherein the at least one fastening improvement element (50) comprises a conformal coating (57) which envelops the haptic device (100).

18. Haptic device (100) according to one of the preceding claims, wherein the at least one reinforcing element (30) projects beyond the base body (10) on a side facing away from the lifting area (31).

19. Haptic device (100) according to one of the preceding claims, wherein the fastening region (39) is covered with the connecting layer (20).

20. Haptic device (100) according to one of the preceding claims, wherein the at least one reinforcing element (30) adjacent to the stroke area (31) has a connecting plate (31') for mounting the haptic device (100).

21. Haptic device (100) according to the preceding claim, wherein the at least one reinforcing element (30) has a reinforcing region (31'') in the transition between the lifting region (31) and the connecting plate (31').

22. Haptic device (100) according to claim 21, wherein the connecting plate (31') is fastened to the lifting area (31) by at least one connecting element (37).

23. Haptic device (100) according to claim 20, wherein the at least one reinforcing element (30) is a separately manufactured element which is fastened to the lifting area (31) by means of at least one connecting element (37). connecting plate (31') for mounting the haptic device (100).

24. Haptic device (100) according to one of the preceding claims, wherein the at least one reinforcing element (30) has a stabilization region (31''') adjacent to the stroke region (31) which extends from the stroke region (31) to the piezoelectric actuator (1).

25. Haptic device (100) according to one of the preceding claims, wherein the piezoelectric actuator (1) has a longitudinal side surface (17) on which two external electrodes (15) for electrically contacting the haptic device (100) are arranged.

26. Haptic device (100) according to the preceding claim, wherein a flexible connecting element (40) is connected to the two external electrodes (15).

27. Haptic device (100) according to claim 26, wherein the flexible connecting element (40) is a flexible printed circuit board or a multi-conductor cable.

28. Haptic device (100) according to claim 26 or 27 and one of claims 8 to 13, wherein a part of the flexible connecting element (40) is arranged between the at least one wing element (53) and the side surface (16, 17) of the base body (10).

29. Haptic device (100) according to one of claims 26 to 28 and claim 17, wherein a part of the flexible connecting element (40) together with the piezoelectric actuator (1) and the at least one Reinforcing element (30) is covered by the conformal coating (57).

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