Electromechanical transducer with layer structure

Abstract

An electromechanical transducer (1, 21, 28) has a layer structure, which comprises in the following order: a first layer (2) having at least one conductive region (3) in at least one plane and being insulated from the outside and serving as an electrical shield; a second layer (6) serving as an adhesive layer that is conductive at least at some points; a third layer (13, 22) comprising an electromechanical functional element; a fourth layer (15, 23) serving as an adhesive layer that is conductive at least at some points; and a fifth layer (17, 24) having at least one conductive region (18) in at least one plane and being insulated from the outside and serving as an electrical shield. In addition, a method for manufacturing such an electromechanical transducer (1, 21, 28) is described.

Description

Technical Field

[0001] The invention relates to an electromechanical transducer having a layer structure. Background Art

[0002] EP 2 372 802 A2 describes an electromechanical transducer comprising at least a bottom supporting layer, electrical and or electromechanical functional elements arranged on the bottom supporting layer, and a top layer with electrical contacts connected to the functional elements.

[0003] For such an electromechanical transducer to be commercially viable, an efficient manufacturing process is required. Summary of the invention

[0004] The invention is therefore based on the object of specifying an electromechanical transducer which is suitable for production on an industrial scale and which operates robustly and reliably. Furthermore, a related manufacturing method is specified.

[0005] In order to solve this problem, an electromechanical transducer having the features of claim 1 is provided.

[0006] The electromechanical transducer according to the invention has a layer structure comprising in the following order:

[0007] a first layer, which has in at least one plane at least one electrically conductive region which is designed to be insulated from the outside and serves as an electrical shield,

[0008] - a second layer, which serves as an adhesive layer which is electrically conductive at least at certain points,

[0009] - a third layer, which comprises electromechanical functional elements,

[0010] - a fourth layer, which serves as an adhesive layer which is electrically conductive at least at certain points,

[0011] A fifth layer, which has in at least one plane at least one electrically conductive region which is designed to be insulated from the outside and serves as an electrical shield.

[0012] The electromechanical transducer according to the invention is characterized by the fact that it can be manufactured in large quantities simply and inexpensively due to its layer structure. The outer layers, i.e. the first and fifth layers, serve in particular to shield the electromechanical functional element so that it cannot be disturbed by external influences such as electromagnetic fields. A further advantage is that the electromechanical transducer according to the invention can be manufactured relatively easily due to the layer structure. In particular, several electromechanical transducers can be manufactured by successively segmenting the layer structure (panel) and superimposing the individual layers in a single process, thereby obtaining the individual transducers.

[0013] In the electromechanical transducer according to the present invention, the second layer and the fourth layer serve as adhesive layers, which in this way connect two adjacent layers, namely the first layer and the third layer and the third layer and the fifth layer, respectively. It is essential in this context that the second layer and the fourth layer are conductive at least at a plurality of points. In this way, electrical connection can be achieved across different layers.

[0014] In the scope of the present invention, it can be arranged that the first layer and / or the fifth layer have contacts exposed to the outside. The contacts can be used to connect electrical connection elements (e.g., circuits). It is also within the scope of the present invention that the contacts are formed as plugs or sockets or electronic components. If the contacts are integrated in the electromechanical transducer, the electrical connection is particularly simple. For example, the contacts can be designed as a memory card, such as an SD card, or a SIM card for a mobile phone.

[0015] By way of particular advantage, in the electromechanical transducer according to the invention it can be provided that each layer has at least one point-shaped electrical contact or through-plating via which the layer is electrically conductively connected to the adjacent layer. In this way, electrical signals can be transmitted to one or two outer layers in a single or multiple (multiple) manner perpendicular to the layer plane.

[0016] Preferably, in the electromechanical transducer according to the present invention, the second to fifth layers have at least one conductive connection to the first layer directly or indirectly via a layer arranged between them and the first layer. Therefore, if there is a need for signal transmission or other reasons, it is preferred that the contact arranged on the first layer can be electrically connected to each single layer.

[0017] A particularly robust structure of the electromechanical transducer is produced when two adjacent layers, preferably all adjacent layers, are bonded to one another by material bonding. This means that all layers are firmly bonded to one another, resulting in a stable structure of the electromechanical transducer.

[0018] In a further embodiment of the invention, it can be provided that at least two adjacent layers, preferably all adjacent layers, are bonded to each other in a material-locked and / or form-fitting manner via a polymer matrix (e.g. a resin matrix). In particular, the second layer and the fourth layer used as adhesive layers can also consist of a polymer matrix or have a resin matrix. Alternatively, they can include an adhesive film, a thermoplastic film or a liquid or viscous adhesive. In this regard, it is envisioned that the interfacial bonding will bond the polymer surface to the polymer surface. However, it can also be provided that the metal surface is bonded to the metal surface via a material-bonded joint, or the polymer surface is bonded to the metal surface via a material-bonded joint. Preferably, at least 20% of the surface area of ​​the interconnected electromechanical transducers is formed by a polymer, in particular by a resin matrix. Alternatively, the material bond can be formed by a resin matrix or a polymer-based adhesive. The adhesive can be adhesive-activated and / or hardened by heating, optionally under pressure.

[0019] Within the scope of the invention, it can be provided that the functional element is designed as one of the following sensors: piezoelectric sensor, capacitive sensor, inductive sensor, conductive sensor, resistive sensor, piezoresistive sensor, pyroelectric sensor, position sensor, gyrometer, Hall sensor, magnetometer, radar sensor, proximity sensor. Each of the above mentioned sensors can be used for a specific measurement task. For example, the mentioned sensors can be used to detect structure-borne sound (i.e. vibrations of the body), or to detect forces, stresses or bendings. Further further quantities can be obtained or calculated from these measured values ​​recorded by the sensor. For example, structure-borne sound vibrations can also be detected as acoustic signals.

[0020] The electromechanical transducer according to the present invention may include an electronic circuit having one or more of the following components: a signal amplifier, a filter, an A / D converter, a signal processing controller, a data storage device, a wireless data transmission module, a wireless power transmission module, an ASIC (application specific integrated circuit), a DSP (digital signal processor), and an FPGA (field programmable gate array).

[0021] It is also within the scope of the invention that the electromechanical transducer according to the invention has several identical or different layers stacked one on top of the other. The order of the layers can be different. For example, the stacked layers can be arranged symmetrically. At least one layer of the electromechanical transducer according to the invention can include a fiber-reinforced polymer. Such a fiber-reinforced polymer is particularly easy to assemble into a layer structure. The adhesive layer of the electromechanical transducer according to the invention can be electrically insulating, at least in sections. For example, a conductive composite can be formed by a conductive polymer, for example with carbon fibers or silver particles as components. It is also possible that the conductivity is present only at multiple points perpendicular to the layer plane, while the adhesive layer is insulating in this plane.

[0022] Within the scope of the invention, one or more functional layers can be integrated directly into the electromechanical transducer. Such layers can include electronic components, sensors or another sensor such as a temperature sensor, a position sensor, a torque sensor, an acceleration sensor or one or more of the electronic circuits mentioned above. Such sensors and circuits can be easily and inexpensively connected by the invention. It is also possible to integrate a printed circuit board fully equipped with electronic components into the transducer according to the invention.

[0023] In the electromechanical transducer according to the invention, at least one layer can be heat-hardenable, or can be hardened, or is self-adhesive. In addition, the electromechanical transducer can have a plurality of layers comprising electromechanical functional elements. Preferably, at least one layer of the electromechanical transducer comprises a fiber-reinforced polymer. Preferably, the adhesive layer is at least sectionally electrically insulating and / or parallel to the plane defined by the adhesive layer.

[0024] Furthermore, the invention relates to a method for manufacturing an electromechanical transducer comprising the following steps:

[0025] - providing a first layer which has in at least one plane at least one electrically conductive area serving as an electrical shield in a mode insulated from the outside,

[0026] - providing a second layer which acts as an adhesive layer which is electrically conductive at least at certain points,

[0027] - providing a third layer, said third layer comprising electromechanical functional elements,

[0028] - providing a fourth layer which serves as an adhesive layer which is electrically conductive at least at certain points,

[0029] - providing a fifth layer, which has in at least one plane at least one electrically conductive area serving as an electrical shield in a mode insulated from the outside,

[0030] - stacking and aligning the first to fifth layers to form a panel area,

[0031] - squeezing the layers under pressure, and

[0032] - Split panel area.

[0033] In the process according to the invention, it can be provided that the layers are pressed together by heating. In particular, the layers can be pressed together for a few minutes or a few seconds, or preferably only a fraction of a second.

[0034] Within the scope of the process, it can be provided that at least one layer is subjected to cleaning or surface activation before the extrusion. The surface activation can take the form of a plasma treatment.

[0035] In the process according to the invention, cold-hardening adhesives, thermoplastic hot-melt adhesives or duromer structural adhesives can be used as adhesive layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further advantages and details of the invention are explained below by way of example with reference to the accompanying drawings. The drawings are schematic representations and show:

[0037] Figure 1is a cross-sectional view of a first embodiment of an electromechanical transducer according to the present invention,

[0038] Figure 2 is a second embodiment of the electromechanical transducer according to the present invention, and

[0039] Figure 3 FIG. 4 is a third embodiment of an electromechanical transducer according to the present invention. DETAILED DESCRIPTION

[0040] Figure 1 is a cross-sectional view and shows an electromechanical transducer 1 having a layer structure. The electromechanical transducer 1 comprises a first layer 2, which has at least one conductive region 3 in at least one plane which is configured to be insulated from the outside and serves as an electrical shield. The planar region 3 forms an outer layer which is electrically insulated from the outside of the electromechanical transducer 1. In addition, the first layer 2 comprises another planar region 4 which is separated from the planar region 3. The two planar regions 3, 4 are embedded in a polymer matrix 5 and are thus materially bonded to each other.

[0041] The first layer 2 is followed by a second layer 6 acting as an adhesive layer. The adhesive layer is electrically conductive at a plurality of points 7. At each of these points 7, there is an electrical contact transverse to the adhesive layer (i.e., from one side of the adhesive layer to the opposite side). From the second layer 6 acting as an adhesive layer, a contact 8 extends perpendicularly to the plane of the layer towards the outside 9 of the electromechanical transducer 1. The contact 8 ends in a contact 10. At Figure 1 In FIG. 1 , it can be seen that further contacts appear at the outer portion 9. Several contacts 11 extend towards the flat region 3. Contacts 12 connect the outer portion 9 via the flat region 4.

[0042] exist Figure 1 In the view of FIG. 1 , the third layer 13 including the electromechanical functional element is located below the second layer 6 serving as an adhesive layer. In the embodiment shown, the electromechanical functional element is designed as a piezoelectric sensor 14. The sensor 14 uses the piezoelectric effect. When mechanical pressure is applied, an electric charge is generated that can be supplied to an amplifier. Subsequently, the signal supplied by the piezoelectric sensor 14 can be processed and evaluated.

[0043] exist Figure 1 In the view of , below the third layer 13, there is a fourth layer 15 serving as an adhesive layer, which is constructed in the same way as the layer 6 serving as an adhesive layer. The layer 15 serving as an adhesive layer is electrically conductive at multiple points. For this purpose, contacts penetrating the adhesive layer are provided at several points 16. The layer 15 serving as an adhesive layer connects the third layer 13 and the fifth layer 17. The fifth layer 17 is constructed essentially like the first layer 2. It includes a conductive area 18 insulated from the outside in one plane. In addition, the fifth layer 17 includes a further planar area 19 separated from the planar area 18 in the thickness direction. Similar to the planar areas 3 and 4 of the first layer 2, the two planar areas 18 and 19 are embedded in a polymer matrix 20.

[0044] From the contact 10 of the outside 9, the contact 8 extends through the second layer 6 serving as adhesive layer and the fourth layer 15 serving as adhesive layer to the fifth layer 17 which is connected in this way to the contact 10. The plurality of contacts serves to make electrical contact between the electromechanical transducer 1 and external components, for example an amplifier or an evaluation circuit.

[0045] All five layers of the electromechanical transducer 1 form a polymer or a fiber-reinforced polymer with conductive or insulating regions arranged in the layers as required. At least at a plurality of points, each layer has at least one conductive contact, either a two-dimensional contact or a through-plating, via which each layer is connected to one or more adjacent layers.

[0046] The electromechanical transducer described in this embodiment can be easily manufactured in large quantities using automated processing. For this purpose, a panel comprising a plurality of electromechanical transducers arranged in rows and columns is produced. After the layers are stacked, compression molding is performed. The panel is then cut to create the individual electromechanical transducers.

[0047] Figure 2 A second embodiment of an electromechanical transducer 21 is shown, which is constructed similarly to the transducer described in the first embodiment. A detailed description of the corresponding components is therefore omitted herein.

[0048] The electromechanical transducer 21 comprises a first layer 2 having a planar region 3 which is insulated from the outside and is electrically conductive and serves as an electrical shield. The first layer 2 is followed by a second layer 6 which serves as an adhesive layer. The third layer 22 comprises an electromechanical functional element designed as a sensor 14. Figure 2 The fourth layer, which is located on the opposite side of the third layer 22 from the layer 6 in the view of FIG. 1 , serves as an adhesive layer.

[0049] The fifth layer 24 forms an outer side 25 opposite to the outer side 9. The fifth layer 24 includes a conductive region 26 which is insulated from the outside and serves as an electrical shield. Figure 2 In FIG. 2 , it can be seen that the electromechanical transducer 21 is symmetrically constructed. Thus, there are two identical sensors 14 , each of which is provided with an adhesive layer on both sides. Figure 2 The intermediate layer 27 is located between the two inner adhesive layers.

[0050] Figure 3 Shown with Figure 2 The electromechanical transducer shown is similar in structure and also has the same Figure 1 The illustrated embodiment is similar to another embodiment of a shielded electromechanical transducer 28 .

[0051] Reference numerals list

[0052] 1 Electromechanical transducer

[0053] 2 First floor

[0054] 3 Plane area

[0055] 4 Plane area

[0056] 5 Polymer matrix

[0057] 6 Second Floor

[0058] 7 o'clock

[0059] 8 Contacts

[0060] 9 External

[0061] 10 Contacts

[0062] 11 Contact

[0063] 12 Contacts

[0064] 13 Third Floor

[0065] 14 Sensors

[0066] 15 Fourth Floor

[0067] 16 o'clock

[0068] 17 Fifth Floor

[0069] 18 Plane Area

[0070] 19 Plane Area

[0071] 20 Polymer matrix

[0072] 21 Electromechanical transducer

[0073] 22 Third Floor

[0074] 23 Fourth Floor

[0075] 24 Fifth Floor

[0076] 25 Outer side

[0077] 26 Regions

[0078] 27 Middle Layer

[0079] 28 Electromechanical transducers

Claims

1. An electromechanical transducer (1, 21, 28), having a layer structure, the layer structure comprising in the following order: - a first layer (2) which has in at least one plane at least one first electrically conductive region (3) which is designed to be insulated from the outside and serves as an electrical shield, - a second layer (6) which serves as an adhesive layer which is electrically conductive at at least one point, - a third layer (13, 22) comprising electromechanical functional elements, - a fourth layer (15, 23) which serves as an adhesive layer which is electrically conductive at least at one point, - a fifth layer (17, 24) having at least one second conductive region (18) in at least one plane which is insulated from the outside and serves as an electrical shield, characterized in that the first layer (2) and / or the fifth layer (17, 24) has a first contact (8) exposed to the outside (9, 25), each layer (2, 5, 13, 15, 17, 22, 23, 24) has at least one contact and a through-plating, the at least one contact is conductive at least at one point, and the layer (2, 5, 13, 15, 17, 22, 23, 24) is conductively connected to an adjacent layer (2, 5, 13, 15, 17, 22, 23, 24) via the through-plating; The contacts include a second contact (10), a third contact (11) and a fourth contact (12), The third contact (11) is electrically connected to the first conductive region (3), The fourth contact (12) is connected to the first plane region (4) of the first layer (2) via the first contact (8) penetrating the first conductive region (3); The second contact point (10) is electrically connected in sequence to another first contact point (8), a conductive point (7) of the second layer, a conductive point of the fourth layer, and a second planar area (19) of the fifth layer; The first conductive region (3) is electrically connected in sequence to another conductive point of the second layer (6), another conductive point of the fourth layer, and the second conductive region (18) of the fifth layer.

2. The electromechanical transducer according to claim 1, characterized in that: The first contact (8) is designed as a plug, or is designed as a socket, or is designed as an electronic unit; The first planar region (4) of the first layer (2) is separated from the first conductive region (3); the first planar region (4) is close to and covers the electromechanical functional element.

3. The electromechanical transducer according to claim 1, characterized in that: The second to fifth layers (6, 13, 15, 17, 22, 23, 24) have at least one electrically conductive connection to the first layer (2), either directly or via a layer arranged between them and the first layer (2).

4. The electromechanical transducer according to claim 1, characterized in that: Two adjacent layers (2, 5, 13, 15, 17, 22, 23, 24) are bonded to one another in a material-to-material bond.

5. The electromechanical transducer according to claim 4, characterized in that: At least two adjacent layers (2, 5, 13, 15, 17, 22, 23, 24) are bonded to one another in a material-locked and / or form-fitting manner via a polymer matrix (5).

6. The electromechanical transducer according to claim 4 or 5, characterized in that: A material bond is formed by the polymer over at least 20% of the surface of the electromechanical transducer (1, 21, 28).

7. The electromechanical transducer according to claim 1, characterized in that: The electromechanical functional element is designed as one of the following sensors: a piezoelectric sensor (14), a capacitive sensor, a conductivity sensor, a resistive sensor, a piezoresistive sensor, a pyroelectric sensor, a gyroscope, a Hall sensor, a magnetometer, a radar sensor.

8. The electromechanical transducer according to claim 1, characterized in that: The electromechanical functional element is designed as an inductive sensor.

9. The electromechanical transducer according to claim 1, characterized in that: The electromechanical functional element is designed as a position sensor.

10. The electromechanical transducer according to claim 1, characterized in that: The electromechanical functional element is designed as a proximity sensor.

11. The electromechanical transducer according to claim 1, characterized in that The electromechanical functional element is designed as an electronic circuit, which includes one or more of the following components: a signal amplifier, a filter, an A / D converter, a control unit for signal processing, a data storage device, a wireless data transmission module, an ASIC (application-specific integrated circuit), a DSP (digital signal processor), and an FPGA (field programmable gate array).

12. The electromechanical transducer according to claim 1, characterized in that: The electromechanical functional element is designed as an electronic circuit which comprises a module for the wireless transmission of electric power.

13. The electromechanical transducer according to claim 1, characterized in that: At least one layer (2, 5, 13, 15, 17, 22, 23, 24) is capable of being hardened or is self-adhesive.

14. The electromechanical transducer according to claim 1, characterized in that: It comprises a plurality of layers including electromechanical functional elements.

15. The electromechanical transducer according to claim 1, characterized in that: At least one layer (2, 5, 13, 15, 17, 22, 23, 24) comprises a fiber-reinforced polymer.

16. The electromechanical transducer according to claim 1, characterized in that: The adhesive layer is at least partially electrically insulating and / or parallel to a plane defined by the adhesive layer.

17. A method for manufacturing an electromechanical transducer (1, 21, 28) according to any one of claims 1 to 16, comprising the following steps: - providing a first layer (2), which has in at least one plane at least one first electrically conductive region (3) which is designed to be electrically insulated from the outside and serves as an electrical shield, - providing a second layer (6) which serves as an adhesive layer which is electrically conductive at least at certain points, - providing a third layer (13, 22), said third layer (13, 22) comprising electromechanical functional elements, - providing a fourth layer (15, 23) which serves as an adhesive layer which is electrically conductive at least at certain points, - providing a fifth layer (17, 24), said fifth layer (17, 24) having in at least one plane at least one second conductive region (18) which is insulated from the outside and serves as an electrical shield, - Stack and align the first to fifth layers (2, 5, 13, 15, 17, 22, 23, 24) to form a panel area, - extruding the layers (2, 5, 13, 15, 17, 22, 23, 24) under pressure, and - Split panel area.

18. The method according to claim 17, wherein: The layers (2, 5, 13, 15, 17, 22, 23, 24) are pressed together by heating.

19. The method according to claim 17, wherein: At least one layer (2, 5, 13, 15, 17, 22, 23, 24) is subjected to cleaning or surface activation before extrusion.

20. The method according to claim 17, wherein: Cold-hardening adhesives, thermoplastic hot-melt adhesives or thermosetting plastic structural adhesives are used as the adhesive layer.

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