DE102012105647A1 - Electrical component for use as e.g. capacitor, has coil including electrical conductor whose longitudinal contact end is conductively connected with electrode, where longitudinal contact ends lie on side of piezoelectric elements - Google Patents

Abstract

The component (1) has an electrically conductive contact layer (11) arranged with an electrode (9) by an electrical conductor (13). A coil (2) and an electrically insulating layer (10) are fitted to a side of piezoelectric elements (3, 3') e.g. piezoelectric actuator, such that a longitudinal contact end (5) of the electrical conductor of the coil electrically contacts the electrically conductive contact layer. Another longitudinal contact end (6) is conductively connected with another electrode (8). The longitudinal contact ends lie on the side of the piezoelectric elements. The electrodes and/or electrically conductive contact layers are formed by metallization.

Description

The invention relates to an electrical element having the features of the preamble of claim 1. Such an electrical element thus contains in combination an electric coil and a piezoelectric element. A piezoelectric element is a component which has at least one piezoelectric element, in the case of this invention a piezoelectric layer, and two electrodes for applying a voltage and for forming an electric field over the material of the piezoelectric layer.

Piezoelectric elements are well known and are used in the prior art for a variety of applications. The piezoelectric effect causes dimensional changes along predetermined axes in piezoelectric materials or elements formed therefrom at an applied voltage or when applying an electric field, for example a shortening of a length and increasing the width. Conversely, deformations of such elements cause the formation of electrical voltages. In that regard, such piezoelectric elements are used as passive elements in order to detect, for example, changes in length or position or to measure loads bearing on a solid body. In the reverse application, such piezoelectric elements are also used as piezoelectric actuators to z. B. triggered by an applied voltage to cause a change in position, for example, the probe tip of a scanning tunneling microscope, or to achieve an acoustic excitation, often in the ultrasonic range, with applied AC voltage.

In many known fields of application, the corresponding piezoelectric elements are contacted by wire and either supplied with an excitation voltage, or a voltage generated by the piezoelectric element is transmitted and supplied via the wired contacting as a measurement signal to a signal processing station.

But are also known applications in which piezoelectric elements are electrically connected wirelessly, in particular as piezoelectric actuators, z. B. for the generation of ultrasound. So is in the DE 10 2007 014 696 B3 a sensor-actuator device is described in which a piezoelectric element is brought into connection with an RFID element which is known to transmit via an antenna from a transmitter by radio receiving an excitation energy carrying signals and transforming them by means of the excitation of a resonant circuit into electrical energy , At the time of the DE 10 2007 014 696 B3 known combination of an RFID element with a piezoelectric element, which combination according to this document and according to the in the 2 The document shown and correspondingly described embodiment variant may also include a direct arrangement of the electrical contacting of the RFID element with the piezoelectric element, the combination element thus obtained for a structural inspection or control of components z. B. used from fiber composite material. For this purpose, corresponding miniaturized such elements are already involved in the production in the material, in particular laminated. By excitation of the RFID component of the combination element by means of the matching resonant frequency, the piezoelement can then later be contacted with a corresponding high-frequency AC voltage generated in the receiver resonant circuit and excited so that it generates an ultrasonic wave within the component. This wave or its passage through the material or a corresponding echo response can then be evaluated in turn with regard to any deviations from the course expected for an undamaged or intact component, for example hairline cracks, fatigue cracks or the like. Damage or changes to the component detect.

The application of such coupled elements of receiver coil and associated with this piezoelectric element for the radio-controlled excitation of the piezoelectric element, for. As for the generation of a sound, in particular ultrasonic signal, but is not limited to the inclusion of such elements in components for the purpose of simple trouble-free in situ material testing. Other fields of application are conceivable in which a wireless controllable sound, in particular ultrasonic excitation, z. B. in the form of directionally radiated ultrasonic signals, is useful. For example, wirelessly activatable direction finding transmitters based on a direction finding signal, e.g. B. for purposes of location, submit, realized.

Common to the known applications is the tendency to miniaturize the corresponding components and at the same time to be able to produce them in a simple manner. The need for miniaturization of the components is obvious. The smaller such components, the easier it is to z. B. include in to be monitored or controlled components or the smaller dimensions may have such components that can be equipped with appropriate combination elements of receiver coil and piezoelectric element. Corresponding size considerations naturally also apply to other fields of application. In addition to the specification of a miniaturization is to demand that even with such a miniaturization, a desired transmitter or excitation frequency can be maintained, the resonant frequency of the electrical Element formed resonant circuit in particular does not drift to higher frequencies. At the same time it must be ensured that even with a further miniaturization, the production of such an electrical combination element can be done with the simplest possible means and for mass production.

These requirements are met by an electrical element having the features of claim 1. Advantageous embodiments and further developments of such an electrical element according to the invention are specified in the dependent claims 2 to 12.

An inventive electrical element thus contains at least one electrical coil, which is wound from an electrical conductor, which has a first and a second longitudinal contact end. The electrical element further includes at least one piezoelectric element. This piezoelectric element has a flat side and a second, the first side opposite, also flat side. It includes at least one piezoelectric layer and on the first and the second side of the piezoelectric element (this may be the piezoelectric layer in the simplest case) applied electrodes. Via the electrodes, the piezoelectric material arranged therebetween, which can be present in one layer, but also in several layers, can be exposed to an electric field. Conversely, however, a voltage can also be tapped off via the electrodes which, in the case of a mechanical load, in particular a deformation, of the piezoelectric element arises due to the piezoelectric effect.

To connect the coil to the piezoelectric element, the first longitudinal contact end of the electrical conductor is contacted with the electrode applied on a first side of the piezoelectric element, and the second longitudinal contact end of the electrical conductor is contacted with the electrode applied to the second side of the piezoelectric element.

The above-described, known from the prior art construction thus allows it to transmit from a transmitter, in particular a radio frequency (RF) transmitter electrical energy in the form of electromagnetic radiation to the coil acting as a receiver antenna, which together with the their associated piezoelectric element forms the characteristic of a resonant circuit electrical components of an inductance and a capacitance, wherein the resonant frequency of this resonant circuit is adapted to the frequency of the electromagnetic excitation. The resonant frequency of the resonant circuit is typically chosen or set to excite the piezoelectric element with a corresponding frequency, typically an ultrasonic frequency. Thus, in a conventional manner, the piezoelectric element thus supplied with energy wirelessly and for generating z. B. ultrasonic waves are excited.

The invention is now distinguished from the prior art by the fact that on the first side of the planar piezoelectric element on at least a portion of the first electrode arranged there, an electrically insulating layer is applied. This has a first electrically conductive contact layer on a side opposite the first electrode. This contact layer is electrically connected to the second electrode via a first electrical conductor. The coil is in the electrical element according to the invention in such a manner on the first side of the piezoelectric element, that is on the side which is covered at least in a section of the electrically insulating layer, set there that the first longitudinal contact end of the electrical conductor of the coil, the first electrically electrically contacted conductive contact layer and that the second longitudinal contact end of the electrical conductor of the coil is conductively connected to the first electrode. In this case, furthermore, both longitudinal contact ends of the electrical conductor of the coil are arranged or lie on the first side of the piezoelement.

The first electrical conductor, which connects the first contact layer to the second electrode, may in particular be a conductor which is in the form of a metallization, a metal foil or a conductive adhesive or otherwise firmly applied to the structure.

The inventive construction of the electrical element allows a simple and reliable in the construction of this element, which in particular allows further miniaturization of corresponding elements. For in the production of a corresponding element in particular the connection of the coil to the piezoelectric element is a critical and error-prone as well as in the handling complicated step. For the electrical connection or contacting of the electrical coil to or with the piezoelectric element is at least one terminal side of the coil, ie a longitudinal contact end of the wound in the coil electrical conductor with the location of the coil opposite side of the piezoelectric element or with the there arranged electrode to connect. The hitherto known practice of guiding a unwound portion of the conductor along the piezoelement to the side opposite the coil and fixing it there for contacting the electrode there, is complicated and, in particular, complicated to implement in automated production processes. In addition, the risk of incorrect connections and increases the production committee grows with increasing miniaturization of the element. Not only that the structures are generally finer, in particular, the diameter of the wound to the coil conductor will have to be smaller in order to achieve corresponding numbers of turns and thus inductances can. However, such wires, if required to be handled for a step as described above, can easily rupture or break so that the electrical contact is broken and the manufactured component becomes unusable.

Here, the construction according to the invention simplifies the manufacture to a great extent, by allowing a simple placement of the coil on the piezoelectric element and connection of the longitudinal contact ends of the conductor to be arranged only in the contact region between the coil and the piezoelectric element to the electrodes of the piezoelectric element. This is made possible by the fact that a contact of the provided on the side of the piezoelectric element, which faces the placement of the coil, provided electrode via the line connected to this electrode, provided on the arrangement side of the coil contact surface. In order to prevent a short circuit with the underlying electrode, the corresponding contact surface is applied to a layer of interposed insulating material. The corresponding preparation of the piezoelectric element by arranging on the one hand the insulating material in the layer, on the other hand the contact surface on the insulating material and the guided between the contact surface and the second electrode conductor can be done comparatively easily in the corresponding partial production of this module. When merging the thus prepared piezoelectric element and the coil, the coil needs to be set only in the appropriate orientation and with appropriately placed longitudinal contact ends of the wound in her electrical conductor on the piezoelectric element, and the contact is made. A connection of the coil to the piezoelectric element can be done in particular by gluing. Today's adhesive technology allows very durable and adjustable in their properties after the choice of adhesive compounds of different materials. In this case, adhesive bonds can also be made electrically conductive by appropriate additions of conductive material in the adhesive, so that not only the mechanical, but also the electrical connection of the coil, in particular the longitudinal contact ends of the conductor can be made to the respective electrical connection points of the piezoelectric element with a corresponding conductive adhesive , Corresponding electrically conductive adhesives are well known, they contain z. As silver or gold particles for the production of conductivity. Alternatively, a connection of the longitudinal contact ends of the conductor but also with other methods, such as the thermocompression bonding or a soldering done. Such methods of mechanical and electrical connection are also very suitable for the procedure according to the invention.

In principle, it is sufficient to provide one of the contacts provided for contacting the electrodes of the piezoelectric element, namely that of the electrode mounted on the side opposite the arrangement location of the coil by forming the contact surface arranged on an interposed electrically insulating layer. The electrode located on the first side on which the coil is placed can be directly contacted by the corresponding longitudinal contact end of the coil. This approximately resulting level and height differences in the only partially covered with the electrically insulating layer piezoelectric element can, for. B. by appropriate introduction of a connecting material, for. B. a correspondingly large volume of an electrically conductive adhesive can be overcome. In view of the fact that such electrical elements in the context of the desired miniaturization in sizes (edge lengths or diameters) in the millimeter range (in any case, clearly below a centimeter) are sought, corresponding stages of small dimension and can be easily z. B. with a volume of such adhesive or else by applying a metal drop as a connecting means or the like. Be overcome. It is also possible in principle to make the electrode layer arranged there on the one hand somewhat thicker and stronger in order to compensate for the corresponding height at least over a certain part there.

However, the production is further simplified, allows a symmetrical structure of the element according to the invention and the design of a total reproducible working combination element allows when the electrically insulating layer on its surface facing the coil not only a first electrically conductive contact layer, but in addition also one of the first electrical contact layer has separate, laterally offset second electrically conductive contact layer, which is electrically connected via a second electrical conductor to the first electrode. As a result, the coil with correspondingly positioned longitudinal contact ends of its electrical conductor can be positioned even better and more easily and arranged on the surface of the electrically insulating layer so that the electrodes of the piezoelement can be connected by means of the contact surfaces and the electrical conductors connecting them to the respective electrodes without passing a longitudinal contact end of the wound in the coil conductor around the piezoelectric element around to the opposite side, there to contact an electrode.

In this case, the electrically insulating layer may advantageously completely cover the first electrode, at least with regard to its upper side facing the coil.

Advantageously, the electrically insulating layer is a non-piezoelectric layer. In this preferred embodiment, the electrically insulating layer does not already serve as a component of the piezoelectric element with regard to its piezoelectric activity. Rather, it is a cover layer, which covers the underlying first electrode of the piezoelectric element and electrically insulated from the overlying structures, in particular from the first contact layer and the longitudinal contact end of the wound into the coil electrical conductor. In principle, however, the functionality of the electrical element according to the invention can also be achieved if the electrically insulating layer has a piezoelectric effect. In particular, when with the electrical element according to the invention directed towards the direction of propagation sound, in particular ultrasonic excitation is to take place, the insulating layer may then be a piezoelectric material, if it is arranged with a different orientation or responds in a different orientation to an applied electric field and so does not disturb the directed sound output or as little as possible. Also, such a construction can lead to unwanted modes of the generated sound signal, which in turn reduce the effectiveness of the entire element. Therefore, a corresponding acoustic radiation of such possibly piezoelectrically acting, electrically insulating layer should be significantly lower than that of the actual piezoelectric element, on the one hand to be able to clearly differentiate the desired excitation from the side effects and on the other hand, as much as possible for to use and convert the energy that is intended for this purpose and not to let the energy loss caused by a parasitic excitation become too great.

In this case, it is also possible, in particular, to produce the insulating layer from a material that is similar in composition to the piezoelectric material of the piezoelectric element in the chemical composition, but in a different physical form, eg, in the case of a piezoelectric material. B. undirected polycrystalline or amorphous. As a result, no piezoelectric effect would be observed in the electrically insulating layer, but this layer can at the same time easily be formed into a uniform production method with the piezoelement, only with correspondingly different process parameters which prevent a piezoelectric effect of this layer.

Advantageously, the piezoelectric element may comprise at least two piezoelectric layers arranged one above another in layers per layer of an electrode layer and electrically connected in parallel over the electrodes, but in particular more than two. Such layer structures of piezoelectric elements are basically known, for. B. from the DE 10 2005 017 108 A1 , They have the advantage that with comparatively thin layer thicknesses of the piezoelectric layers with a given voltage high field strengths can be achieved in the piezoelectric layers, which can achieve a high amplitude of the excitation obtained with the piezoelectric element. In addition, a stack of a plurality of stacked, each separated by interposed electrodes piezoelectric layers, in terms of electrical effect as a parallel connection of individual capacitors to understand. Such a capacitor is formed by two opposing electrodes with the interposed dielectric of the piezoelectric layer. Such a parallel connection of capacitors leads to a summation of the respective individual capacitances, that is to say to an increase in the total capacitance, which leads to a reduction of the electrical resonant circuit formed by the coil and the piezoelement connected therewith, which contains the many piezoelectric layers Resonant frequency leads, which is particularly desirable in a further miniaturization of such a component to let a corresponding excitation frequency, which is indeed coupled in particular with a desired frequency of the ultrasonic response, not to slide too high values.

In order to maintain an intended resonance frequency of the resonant circuit in the miniaturization process of the overall system, when using such a multilayer piezo element, for example, the number of turns in the coil can be chosen to be comparatively small, since the increased capacitance in the resonant circuit allows a reduction of the corresponding inductance. A coil with a smaller number of turns can be miniaturized more easily; In particular, the wire thickness does not have to be reduced so much, which on the one hand has a more reliable manufacturing result and on the other hand reduces the electrical resistance in the coil and thus reduces harmful energy losses for the entire system.

In such a construction, in particular the individual piezoelectric layers are arranged such that the required for the excitation length change, which is achieved at an applied voltage or an applied electric field, added (there is a mechanical series circuit), so that a large Amplitude of the excitation response at a predetermined voltage can be obtained.

The individual components, in particular individual layers, of the piezoelectric element, the insulating layer and the contact layer can advantageously be mechanically frictionally connected in a thick-film process, in particular by sintering. This may apply only to some of these components, eg. B. the individual piezoelectric layers of a constructed of two or more such layers piezoelectric element with the electrodes arranged between these.

Advantageously, the piezoelectric element is used as a piezoelectric actuator, in particular for generating a sonic, in particular ultrasonic excitation. Basically, it is also conceivable to use the piezoelectric element as a passive element, so here to design a sensor, as long as a suitable frequency of mechanical excitation of the piezoelectric element generates a sufficient amount of energy to the resonant circuit and arranged therein coil with a for in the Near this element arranged receiver emitted perceptible transmission power.

It has already been mentioned above that the longitudinal contact ends of the coil z. B. can be set with an electrically conductive adhesive to the respective contacted surfaces. A corresponding configuration of the electrodes and / or the contact layer (s) can also be effected by an electrically conductive adhesive, as long as its conductivity is sufficient to spend sufficient charges on the electrodes. Thus, for example, in the case of a multi-layered piezoelectric element, the individual piezoelectric layers can be bonded to one another with an electrically conductive adhesive, so that in addition to the mechanical bonding of the layers by the adhesive, the intervening electrodes are formed at the same time.

Alternatively, the electrodes and / or the contact layer (s) also by applying a metallization, for. B. a gold or silver coating or thin metallic or other electrically conductive films may be formed. Mixed forms are also conceivable, wherein z. B. the electrodes are formed by metallization or films, contact layer (s) by electrically conductive adhesive, or another such possible combination.

In order to use an inventive electrical component for later use, this can be encapsulated as a whole. Such encapsulation can be done, for example, by casting in a plastic resin material, by introducing it into a plastic or metal capsule or the like. In such an encapsulation, such an electrical element z. B. in a reusable component, such as an element made of a fiber-reinforced plastic are introduced to this by excitation of the electrical element z. B. structural checks to make. If an acoustic excitation is to take place with the piezoelectric element, it must be ensured during the encapsulation that corresponding sound waves, in particular ultrasonic waves, can be transmitted from the piezo element through the material of the capsule with the highest possible efficiency, ie low loss. These considerations play a role in the selection of the material for the encapsulation, on the other hand, in the positioning of the piezoelectric element with respect to a possible capsule role, as well as in the determination of appropriate wall thicknesses. In this case, the piezoelectric element should rest directly on the wall of the encapsulation with a side intended for the emission of the sound, in particular ultrasonic waves, and not there experience further weakening or even scattering of the signal with a gap filled with air or with other material, if one Such dispersion is not sought and desired for reasons of specific application.

In order to increase its inductance and thus influence the resonant frequency of the resonant circuit formed by the piezoelectric element and the electrically combined coil, which is in turn reduced as the inductance increases, the coil can have a corresponding core, in particular such made of a ferromagnetic material, be provided.

In principle, it is also conceivable that more than one coil is arranged in the electrical element according to the invention and mechanically fixed and electrically contacted in the manner described above. For example, another coil could be mechanically and electrically connected to such a system via a layer of electrically insulating layer applied on the second side of the piezoelectric element and contact layer (s) present there and be part of the electrical element.

Also, the electrical element in addition to one or more piezoelectric elements, one or more coils, of which components it contains at least one each, optionally also contain other electrical or electronic functional elements, such. As capacitors, control chips or the like. However, the electrical element according to the invention is already in the simplest embodiment with a coil which is contacted with a (possibly multi-layered) piezoelectric element and mechanically connected, fully functional.

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying figures. Showing:

1 a schematic perspective view of an electrical element according to the invention to illustrate its basic structure;

2 in a schematic exploded view of the structure of an electrical element according to the invention in a first design variant; and

3 one of the 2 corresponding representation of an alternative design variant of an electrical element according to the invention in a schematic exploded view.

The invention will be described with reference to an exemplary embodiment and with reference to the accompanying figures. The figures are purely schematic representations and neither to scale nor detail. Rather, they are limited to the representation of the essential features for explaining the invention.

Das in 1 dargestellte elektrische Element ist in der Realisierung typischerweise von geringer Größe, insbesondere von einer Größe mit einem Durchmesser von unter 1 cm, insbesondere unter einem halben Zentimeter realisiert, um dieses entsprechend miniaturisiert in die unterschiedlichsten Anwendungen bringen zu können. 1 shows an electrical component 1 according to the invention in a highly schematic representation. This electrical component 1 combines a coil 2 which is wound from an electric conductor, whose in the 1 not shown longitudinal contact ends with a planar piezoelectric element 3 are contacted such that a first longitudinal contact end of the conductor with a on a first side of the planar piezoelectric element 3 arranged electrode disposed electrically, a second longitudinal contact end of the electrical conductor with a second, on the opposite side of the first side of the piezoelectric element electrode is electrically connected. This way is in the combination of the coil 2 and the planar piezoelectric element 3 which is formed by the arrangement of the two electrodes separated from the piezoelectric material, which is electrically insulating, a capacitor, a resonant circuit. In the center of the one with an end face on the planar piezoelectric element 3 attached coil 2 , is a core 4 arranged on a ferromagnetic material, around which are the turns of the coil 2 run. This core 4 provides an increase in the inductance L of the coil 2 , which has a decreasing effect on the resonant frequency of the resonant circuit formed with the electrical component, which is proportional to the factor

This in 1 The illustrated electrical element is typically realized in the realization of small size, in particular of a size with a diameter of less than 1 cm, in particular less than half a centimeter, in order to be able to bring this miniaturized in a variety of applications.

According to the invention, the connection of the coil 2 to the piezoelectric element 3 over the in 2 realized and described below construction realized. In 2 are the two elements coil 2 and piezoelectric element 3 shown separated from each other in an exploded view to illustrate this structure. Schematically, in this figure, two longitudinal contact ends of the in the coil 2 wound conductor presented. A first longitudinal contact end 5 of the conductor is here as from the outside of the coil 2 radially inwardly on the surface of the piezoelectric element 3 shown turned facing. A second longitudinal contact end 6 extends diametrically opposite in this representation of the the core 4 facing inside of the coil 2 turned outward on the piezoelectric element 3 facing end face of the coil 2 , About these two longitudinal contact ends 5 . 6 is the coil 2 with the piezo element 3 electrically connected in the manner described below.

The piezo element 3 consists in this embodiment of a single piezoelectric layer 7 which has electrodes applied flat on opposite sides. A first electrode 8th is located on one of the coil 2 facing top of the piezoelectric layer 7 and here is merely a dividing line between the above-arranged element to be described later and the piezoelectric layer 7 indicated. A second electrode 9 is located on the underside opposite the top, which is that of the coil 2 opposite side of the piezoelectric layer 7 is. This too is merely indicated as an edge line, but extends over the entire piezoelectric layer in a planar manner 7 on this page. Through the piezoelectric layer 7 and the two electrodes 8th . 9 is the piezo element 3 educated. On the piezoelectric layer 7 remote from the top of the first electrode 8th here is this first electrode 8th completely covering electrically insulating layer 10 applied. This has in this embodiment two contact surfaces, a first contact surface 11 and a second contact surface 12 on which contact surfaces 11 . 12 electrically conductive and are electrically contacted. From the first contact surface 11 extends, for example, formed by a metallization, over the edge of the piezoelectric element 3 to the second electrode 9 inserted conductor 13 who has the first contact surface 11 with the second electrode 9 connects electrically, which electrical connection through a Kontaktierungsfortsatz 14 on the ladder 13 is indicated.

The second contact surface 12 is about a leader 15 in a similar manner with an electrically conductive connection to the first electrode 8th Mistake. The electrical connection of the conductor 15 to the first electrode 8th is also here via a Kontaktierungsfortsatz 16 illustrated.

Recognizable are the two electrical contact surfaces 11 . 12 not in electrical connection with each other, are electrically isolated from each other. Here are the contact surfaces 11 . 12 aligned and dimensioned so that they are in a like 2 illustrates aligned spooling of coil 2 on piezo element 3 or on the contact surfaces 11 . 12 with the longitudinal contact ends 5 . 6 get into mechanical contact and electrical connection. These are the longitudinal contact ends 5 . 6 removed from any insulation and can make electrical connection to the corresponding conductive pads 11 . 12 produce. In this illustrated embodiment, the first longitudinal contact end 5 with the first electrical contact surface 11 connected, the second longitudinal contact end 6 with the second electrical contact surface 12 , This is how the coil works 2 with its two conductor ends over the first longitudinal contact end 5 with the second electrode 9 of the piezo element 3 electrically connected, with the second longitudinal contact end 6 with the first electrode 8th of the piezo element 3 , This type of connection can be easily made, in particular, can be a good and solid mechanical and electrical connection of the coil to the as in 2 in the lower part of the figure separately shown composite element of piezoelectric element 3 and insulating layer applied thereon 10 with the contact surfaces 11 . 12 be connected by being glued with their longitudinal contact ends by means of an electrically conductive adhesive there. This not only creates the mechanical connection between the coil and the other components, but also the electrical coupling and connection of the longitudinal contact ends 5 . 6 with the electrically conductive contact surfaces 11 . 12 , As mentioned above, a mechanical and electrical connection between the longitudinal contact ends 5 . 6 of the conductor of the coil 2 as well as by other methods, such as thermocompression bonding or soldering can be achieved.

Although in 2 the electrically insulating layer 10 as continuous the first electrode 8th covering and two contact surfaces 11 . 12 shown exhibiting, such an embodiment falls under the invention and the invention can be realized accordingly, in the z. B. the in 2 left section of the electrically insulating layer 10 deleted, with this the second contact surface 12 , the leader 15 and about the contacting process 16 interpreted connection to the first electrode 8th , Because the simple construction and contacting and mechanical fixing can also be achieved by the second longitudinal contact end 6 the coil 2 or to this coil 2 wound electrical conductor directly to the first electrode 8th applied, with this mechanically and electrically connected. This can be z. As easily done by a formed in this position with a larger material thickness adhesive layer, as long as it is made sufficiently conductive by appropriate design of the adhesive (for example, silver additives).

In the structure according to the invention, in which initially the piezoelectric element 3 with the electrically insulating layer 10 to provide and on the at least one contact surface 11 a connection from that of the coil 2 facing upper side to the arranged on the opposite side of the second electrode 9 is electrically produced, is the components 1 easy to produce. Because the piezo element 3 can easily in the like in 2 can be prepared in the form shown, then the coil 2 in which only the two longitudinal contact ends 5 . 6 of the electrical conductor as shown schematically here on an end face must be prepared and arranged, directly mechanically and electrically with the piezoelectric element 3 be connected or with the on this piezoelectric element 3 applied insulating layer 10 , This saves in particular a lead around a free conductor end of the coil 2 around the piezo element 3 around the bottom and arranged there second electrode 9 , In this way, even with a further advanced miniaturization of the electrical component 1 the production is kept simple and in particular also sufficiently automated.

The electrically insulating layer 10 is advantageously a non-piezoelectric layer, so that no piezoelectric effects are generated in the region of this layer, which could lead to unwanted losses or interference signals.

The in 2 In particular, the construction shown results in an electrical component, which the piezoelectric element 3 has as a piezoelectric actuator and controlled by a wirelessly transmitted power supply by means of electromagnetic radiation induced excitation of the resonant circuit of coil 2 and piezoelectric element 3 when irradiated with the resonant frequency by the changing fields and concomitant dimensional changes of the piezoelectric element following the excitation frequency 3 a vibration excitation of the piezoelectric element 3 causes, in particular a sonic, more preferably ultrasonic generation. This can be in the known manner, for. B. as described above with reference to the discussed prior art, can be used.

3 shows a modified embodiment of an alternative electrical component 1' , The structure of the coil 2 is unchanged from the structure of the coil of the previously described embodiment, which is why here using identical reference numerals in the 3 to the description of the preceding 1 and 2 Reference can and can be made to this.

Also the electrically insulating layer 10 and the contact surfaces arranged thereon 11 and 12 in the manner described above with the longitudinal contact ends 5 . 6 the coil 2 are brought into mechanical and electrical connection or brought in composite electrical element, are unchanged in construction. Only the planar piezoelectric element 3 ' has a different structure. The piezo element shown here 3 ' is multi-layered, consists of three piezoelectric layers 7 ' stacked on top of each other. Also the piezo element 3 ' is over a first electrode 8th and a second electrode 9 contacted and with the coil 2 electrically connected.

These electrodes 8th . 9 in turn sit as a release layer in the stack of piezoelectric layers 7 ' to the top and the coil 2 nearest arranged piezoelectric layer 7 ' and the insulating layer 10 and on the bottom, so that of the coil 2 opposite side of the bottom piezoelectric layer 7 ' , Between the individual piezoelectric layers 7 ' are intermediate electrodes 20 attached, which are also visible only as edges of the surface between these respective layers extending structures in the figure.

Designed differently in this embodiment, the contact surfaces 11 respectively. 12 with the electrodes connecting conductors 13 ' and 15 ' , It has remained the same over the ladder 13 ' the first contact surface 11 with the second electrode 9 (again indicated by the Kontaktierungsfortsatz 14 ) and the second conductor 15 ' with the first electrode 8th electrically connected, which in turn via the contacting extension 16 is illustrated. New to this structure is now that of the first contact surface 11 connected leaders 13 ' also with one of the intermediate electrodes 20 that is, between the uppermost arranged, the coil 2 nearest piezoelectric layer 7 ' and the underlying piezoelectric layer 7 ' electrically connected, resulting in a further contacting extension 21 is indicated in the figure. With the further intermediate electrode 20 between the piezoelectric layer located at the bottom 7 ' that is the coil 2 most distant piezoelectric layer 7 ' and the piezoelectric layer disposed above 7 ' , ie the middle piezoelectric layer 7 ' is located, is the leader 15 ' contacted, here what about another contacting process 22 is illustrated. With the intermediate electrodes 20 both are adjacent piezoelectric layers 7 ' contacted. In this respect, the individual piezoelectric layers 7 ' electrically connected in parallel, the orientation of these layers 7 ' to amplify the mechanical effect in each case by 180 ° is rotated, as well as the voltage applied to a given voltage electric fields are reversed by 180 °.

By the parallel connection of the piezoelectric layers 7 ' At the same time, a parallel connection of the individual capacitors formed in this way takes place, which leads to a comparison with the embodiment according to FIG 2 higher capacity of the overall construct leads to the effect of lowering the resonant frequency of the resonant circuit realized with the electronic component. This lowering of the resonant frequency allows a further miniaturization for the frequency to be maintained.

LIST OF REFERENCE NUMBERS

1

electrical component

1'

electrical component

2

Kitchen sink

3

planar piezoelectric element

3 '

planar piezoelectric element

4

core

5

Longitudinal contact end

6

Longitudinal contact end

7

piezoelectric layer

7 '

piezoelectric layer

8th

first electrode

9

second electrode

10

electrically insulating layer

11

first contact surface

12

second contact surface

13

ladder

13 '

ladder

14

Kontaktierungsfortsatz

15

ladder

15 '

ladder

16

Kontaktierungsfortsatz

20

intermediate electrode

21

Kontaktierungsfortsatz

22

Kontaktierungsfortsatz

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007014696 B3 [0004, 0004]
• DE 102005017108 A1 [0020]

Claims (12)

Electrical element comprising at least one of a first and a second longitudinal contact end ( 5 . 6 ) having an electrical conductor ( 2 ) and at least one piezoelectric element having a first planar side and a second piezoelectric element which is opposite the first side and also having a planar surface ( 3 . 3 ' ), which comprises at least one piezoelectric layer ( 7 . 7 ' ) and on the first and the second side of the piezoelectric element ( 3 . 3 ' ) applied electrodes ( 8th . 9 ), wherein the first longitudinal contact end ( 5 ) of the electrical conductor with the on a first side of the piezoelectric element ( 3 . 3 ' ) applied electrode ( 9 ) and the second longitudinal contact end ( 6 ) of the electrical conductor with the on a second side of the piezoelectric element ( 3 . 3 ' ) applied electrode ( 8th ) is contacted, characterized in that on the first of the sides of the planar piezoelectric element ( 3 . 3 ' ) on at least one subsection of the first electrode ( 8th ) an electrically insulating layer ( 10 ) applied to one of the first electrodes ( 8th ) opposite side a first electrically conductive contact layer ( 11 ), which via a first electrical conductor ( 13 ) with the second electrode ( 9 ) is electrically connected, and that the coil ( 2 ) on the first side of the piezoelectric element ( 3 . 3 ' ) on the arrangement of piezoelectric element ( 3 . 3 ' ) and electrically insulating layer ( 10 ) and it is determined there that the first longitudinal contact end ( 5 ) of the electrical conductor of the coil ( 2 ) the first electrically conductive contact layer ( 11 ), that the second longitudinal contact end ( 6 ) of the electrical conductor of the coil ( 2 ) with the first electrode ( 8th ) is conductively connected and that both longitudinal contact ends ( 5 . 6 ) of the electrical conductor of the coil ( 2 ) on the first side of the piezoelectric element ( 3 . 3 ' ) lie. Electrical element according to claim 1, characterized in that on the electrically insulating layer ( 10 ) a second one of the first contact layer ( 11 ) electrically separated electrically conductive contact layer ( 12 ) is applied, which via a second electrical conductor ( 15 ) with the first electrode ( 8th ) is electrically connected, and that the coil ( 2 ) on the electrically insulating layer ( 10 ) is arranged so that the first longitudinal contact end ( 5 ) the first contact layer ( 11 ) and the second longitudinal contact end ( 6 ) the second contact layer ( 12 ) contacted electrically. Electrical element according to claim 2, characterized in that the electrically insulating layer ( 10 ) the first electrode ( 8th completely covered. Electrical element according to one of the preceding claims, characterized in that the electrically insulating layer ( 10 ) is a non-piezoelectric layer. Electrical element according to one of the preceding claims, characterized in that the electrically insulating layer ( 10 ) of one in the chemical composition to the material of the piezoelectric element ( 3 . 3 ' ) formed identical material, but due to other physical structure without piezoelectric effect. Electrical element according to one of the preceding claims, characterized in that the piezo element ( 3 ' ) at least two interposition of an electrode layer ( 20 ) arranged one above the other in layers, and over the electrodes ( 8th . 9 . 20 ) electrically connected in parallel piezoelectric layers ( 7 ' ) having. Electrical element according to claim 6, characterized in that the piezoelectric layers ( 7 ' ) are interconnected mechanically in series, that is to say to the piezoelement ( 3 ' ) applied voltage undergo a mechanical deformation in the same direction. Electrical element according to one of the preceding claims, characterized in that the individual components, in particular individual layers, of the piezoelectric element ( 3 . 3 ' ), the insulating layer ( 10 ) and the contact layer ( 11 ) are mechanically non-positively connected in a thick-film process, in particular by sintering. Electrical element according to one of the preceding claims, characterized in that the piezo element ( 3 . 3 ' ) acts as a piezoelectric actuator. Electrical element according to one of the preceding claims, characterized in that the longitudinal contact ends ( 5 . 6 ) of the electrical conductor of the coil ( 2 ) with an electrically conductive adhesive to the respectively contacted surfaces ( 11 . 12 ). Electrical element according to one of the preceding claims, characterized in that the electrodes ( 8th . 9 . 20 ) and / or the contact layers ( 11 . 12 ) are formed by an electrically conductive adhesive. Electrical element according to one of Claims 1 to 10, characterized in that the electrodes ( 8th . 9 . 20 ) and / or the contact layers ( 11 . 12 ) are formed by a metallization.

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