Abstract:
An apparatus and a method for the excitation and/or damping and/or detection of structural oscillations of a plate-shaped device by means of a piezoelectric strip device are described. The apparatus comprises a carrier device ( 1 ), at a distance from which the plate-shaped device ( 10; 10   a ) is disposed by way of a space ( 11 ), wherein the piezoelectric strip device ( 2; 2   a,    2   b;    2   a′,    2   b′,    2   c;    2   d,    2   e,    2   f;    2′; 2   g,    2   h;    2   i,    2   j;    2   k,    2   l,    2   m;    2   n ) includes a plurality of piezoelectric strip elements ( 2; 2   a,    2   b;    2   a′,    2   b′,    2   c;    2   d,    2   e,    2   f;    2′; 2   g,    2   h;    2   i,    2   j;    2   k,    2   l,    2   m;    2   n ), which each are connected to the carrier device ( 1 ) and to the plate-shaped device ( 10; 10   a ), wherein the strips ( 2; 2   a,    2   b;    2   a′,    2   b′,    2   c;    2   d,    2   e,    2   f;    2′; 2   g,    2   h;    2   i,    2   j;    2   k,    2   l,    2   m;    2   n ) can be excited into longitudinal changes, thereby causing the excitation and/or damping and/or detection of structural oscillations of the plate-shaped device ( 10; 10   a ), and wherein the piezoelectric strips ( 2; 2   a,    2   b;    2   a′,    2   b′,   2   c;    2   d,    2   e,    2   f;    2′; 2   g,    2   h;    2   i,    2   j;    2   k,    2   l,    2   m;    2   n ) are configured and connected to the plate-shaped device ( 10; 10   a ) such that the transmission of oscillations takes place in a substantially punctiform manner.

Description:
BACKGROUND INFORMATION 
       [0001]    The present invention relates to a device an a method for the excitation and/or damping and/or detection of vibrations of a plate-shaped device using a piezoelectric strip device. 
         [0002]    Although it may be applied to any system, the present invention and the fundamental problems it addresses will be explained with reference to systems that include a glass plate or a plastic plate or a printed circuit board as the plate-shaped device. 
         [0003]    The older German patent application DE 10 2007 012 925 describes a method and a device for damping structural vibrations of a carrier device using a piezoelectric actuator device. The piezoelectric actuator device includes a strip, which may be piezoelectrically excited to generate longitudinal and/or transverse vibrations that dampen the structural vibrations, that includes a first end region and a second end region, and that is connected at least at either the first end region or a second end region to a surface of the carrier device in such a manner that the longitudinal and/or transverse vibrations may be transmitted to the carrier device. The dimensions of the strip are therefore substantially smaller than those of the carrier device, and so the vibrations are transmitted in a substantially punctiform manner. 
         [0004]      FIG. 13  shows a device for damping structural vibrations of a carrier device using a piezoelectric actuator device according to the older German patent application DE 10 2007 012 925. 
         [0005]    In  FIG. 13 , a carrier device is labeled using reference numeral  1 . A piezoelectric actuator device in the form of a strip  2 , which is piezoelectrically excitable to generate longitudinal and/or transverse vibrations that damp the structural vibrations, is installed on surface OF of carrier device  1 . Strip  2  includes a first end region E 1  and a second end region E 2 . First end region E 1  is connected via bonding in region  3   a  to surface OF of the carrier device, and second end region E 2  is connected via bonding in region  3   b  to surface OF of carrier device  1 . The connection of strip  2  to surface OF is not limited to the strip-shaped bonding that is shown, however. 
         [0006]    Strip  2  extends such that it arches above surface OF, thereby spanning a cavity  6  in the manner of a bridge. An additional mass device  5  is installed in the middle of the side of strip  2  that faces away from surface OF. The purpose of mass device  5  is to produce a reaction force to dampen the structural vibrations. Strip  2  is multilayered in design. In the middle thereof, a piezoelectric ceramic layer  20  is located, which may be electrically activated using electrode layers  21  which are adjacent thereto. An epoxy resin layer  21  and a polyimide layer  22  are located on and under the electrode layers. Electrode layers  21  are electrically connected via a connection device, which is not depicted, in order to couple the vibrations, which extend in the longitudinal and/or transverse direction of strip  2 , into strip  2 . 
         [0007]    If only longitudinal vibrations are coupled into piezoelectrically excitable strip  2 , as in the present example, this results—due to the geometric configuration—in a vibration mode S 1 , in which mass device  5  is deflected downwardly and upwardly, perpendicular to surface OF along the double arrow shown in  FIG. 13 . 
         [0008]    Although this is not shown in the figure, strip  2  has a substantially smaller extension than carrier device  1 , e.g., the size of strip  2  is in the range of 1-2 cm long×0.5 cm wide, and the size of carrier device  1  is in the range of 10-20 cm long×5-10 cm wide. 
       ADVANTAGES OF THE INVENTION 
       [0009]    The device according to the present invention and as recited in claim  1 , and the method according to the present invention and as recited in claim  14  have the advantage that they create a new family of loudspeaker devices, sound absorbing devices, and vibration sensor devices or vibration isolation devices which may be used, e.g., on transparent surfaces as needed. Very broad applications are possible, in particular applications in motor vehicles, electronics, and mechanical constructions. 
         [0010]    The features referred to in the dependent claims relate to advantageous developments and improvements of the subject matter of the present invention. 
         [0011]    According to a preferred development, the piezolelectric strip elements include a group of one or more piezolelectric strip elements that have a first end and a second end that are connected to the carrier device, and that include a middle region that is connected to the plate-shaped device and is arched, thereby forming a cavity that faces the carrier device. Other geometries may also be used, in particular a series or parallel connection of the strip elements or a configuration as a continuous strip that includes a plurality of interlinked strip elements. 
         [0012]    According to a further preferred development, a guide plate, which is connected to the carrier device, is located above the strip element, includes an opening above the middle region of the strip element, and is designed such that it prevents an edge region of the strip element from becoming displaced relative to the carrier device. It is therefore possible to attain large displacements using long strip elements. 
         [0013]    According to a further preferred development, the guide plate has an electrode function for the strip element. In addition, dissipation heat that is produced during the piezoactivity may be directed away via the guide plate. 
         [0014]    According to a further preferred development, the device is designed to excite structural vibrations of the plate-shaped device, and it includes a loudspeaker function. 
         [0015]    According to a further preferred development, the plate-shaped device is a cover of a mobile electronic device, in particular a portable computer. 
     
    
     
       DRAWING 
         [0016]    An embodiment of the present invention is presented in the drawing and is described in greater detail in the description that follows. 
           [0017]      FIGS. 1   a - c  show a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a first embodiment of the present invention;  FIG. 1   a  shows a top view;  FIG. 1   b  shows a sectional view along line A-A′ in  FIG. 1   a , and  FIG. 1   c  shows an enlarged view across section A 1  in  FIG. 1   a;    
           [0018]      FIG. 2  shows a Bode plot which is used to illustrate the frequency behavior of the device according to  FIGS. 1   a - c;    
           [0019]      FIG. 3  shows an embodiment of a device according to  FIGS. 1   a - c;    
           [0020]      FIG. 4  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a second embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0021]      FIG. 5  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a third embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0022]      FIG. 6  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a fourth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0023]      FIG. 7  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a fifth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0024]      FIG. 8  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a sixth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0025]      FIG. 9  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a seventh embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0026]      FIG. 10  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to an eighth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0027]      FIG. 11  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a ninth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c;    
           [0028]      FIG. 12  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a tenth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c ; and 
           [0029]      FIG. 13  shows a device for damping structural vibrations of a carrier device using a piezoelectric actuator device according to the older German patent application DE 10 2007 012 925. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0030]    In the figures, the same reference numerals are used to label elements that are the same or that perform the same function. 
         [0031]      FIGS. 1   a - c  show a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a first embodiment of the present invention;  FIG. 1   a  shows a top view;  FIG. 1   b  shows a sectional view along line A-A′ in  FIG. 1   a , and  FIG. 1   c  shows an enlarged view across section A 1  in  FIG. 1   a.    
         [0032]    In  FIGS. 1   a - c , a carrier device in the form of a metal or plastic frame is labeled using reference numeral  1 . A plate-shaped device  10  in the form of a glass plate is installed over a piezoelectric strip device  2  at a distance from carrier device  1 , separated by an intermediate space  11 . Piezoelectric strip device  2  includes a plurality of piezoelectric strips  2  that are connected to carrier device  1  and to plate-shaped device  10 . 
         [0033]    The dimensions of strips  2  are substantially smaller than those of carrier device  1  and plate-shaped device  10 , and so the coupling of strips  2  is considered to be substantially punctiform. 
         [0034]    In the configuration shown in  FIGS. 1   a - c , twelve strips  2  are located along and parallel to periphery  101  of plate-shaped device  10 . The dots shown in  FIG. 1   a  indicate the points at which upper middle region M of strips  2  are coupled to plate-shaped device  10 . The lines drawn through the dots represent the longitudinal placement of strips  2  relative to carrier device  1 . 
         [0035]    As shown in  FIG. 1   c , every piezoelectric strip  2  is connected at a first end region E 1  and a second end region E 2  in regions  3   a  and  3   b , respectively, to surface OF of carrier device  1 , e.g., via bonding. The top side of piezoelectric strip  2  is connected via its upper middle region M in region  3   c  to the underside of plate-shaped device  10 , e.g., via bonding. Strips  2  extend such that they arch above surface OF, thereby spanning a cavity  6  in the manner of a bridge. 
         [0036]    Strips  2  are multilayered in design. In the middle thereof, a piezoelectric ceramic layer  20  is located, which may be electrically activated using electrode layers  21  which are adjacent thereto. An epoxy resin layer  22  (or a thermoplastic layer) and a polyimide layer  23  are located on and under electrode layers  21 . Electrode layers  21  are electrically connected via a connection device (which is not shown) to a control device C. 
         [0037]    Via control device C, it is basically possible to provide three different functionalities, in combinations, if necessary. The first functionality is an excitation of structural vibrations of plate-shaped device  10  using piezoelectric strip  2  (loudspeaker operation). The second functionality is a damping of structural vibrations of plate-shaped device  10  using piezoelectric strip  2  (vibration decoupling operation). The third functionality is a detection of structural vibrations in plate-shaped device  10  using piezoelectric strip device  2  (sensor operation). 
         [0038]    Which of the functionalities is realized in a special device depends on the specific application. 
         [0039]    The basic principle of creating/damping/generating structural vibrations in plate-shaped device  10  lies in the change in length of piezoelectric strips  2 , which causes a movement in the direction of arrow S 1  perpendicular to surface OF of carrier device  1 , and therefore a related deflection of the coupling points of plate-shaped device  10 . The deformation of plate-shaped device  10  results in solid-translational vibrations and, to a lesser extent, to undesired bending vibrations. To generate the desired solid-translational vibrations, the ratio thickness/(width x length) of plate-shaped device  10  should be selected accordingly. These vibrations produce compression waves in the surrounding medium, e.g., in air. If plate-shaped device  10  is a glass surface, as in the current example, it may be used to realize a transparent window loudspeaker. 
         [0040]      FIG. 2  shows a Bode plot which is used to explain the frequency behavior of the device according to  FIGS. 1   a - c.    
         [0041]    Curve B in  FIG. 2  shows transmission characteristics A of a device according to  FIGS. 1   a - c  in loudspeaker operation. In contrast, curves A show transmission characteristics of known loudspeakers having column-shaped piezoactuators, in which Eigen modes of the bending frequencies play a main role and result in nonuniform frequency characteristics, which is undesired for loudspeakers. 
         [0042]    However, curve B of the device according to the present invention and depicted in  FIGS. 1   a - c  has a nearly ideal, flat frequency characteristic that makes it possible to transmit every frequency component of the signal uniformly within the bandwidth of the loudspeaker. In other words, the bending vibrations are not noticeable when plate-shaped device  10  has a suitable stiffness. 
         [0043]    Since plate-shaped device  10  has a large reflection surface, the transmitted sound has a higher quality than a punctiform loudspeaker. The actuator component of the loudspeaker in the form of strips  2  is not visible and does not limit the transparency if plate-shaped device  10  is composed of a transparent material. The actuator component of the loudspeaker is lightweight and contains no magnetic conductor materials, nor does it contain a winding, as an electrodynamic actuator. The actuator component of the loudspeaker requires very little installation space and may be installed entirely within the enclosing frame or carrier. The installation height is typically in the range of 2 to 3 mm. Due to it structure, this type of loudspeaker is very robust, and although the actuator device contains elements that have an assembled structure, it does not contain elements that slide on top of one another. 
         [0044]    The positions of piezoelectric strips  2  should be defined with consideration for natural vibration modes of plate-shaped device  10 . 
         [0045]      FIG. 3  shows an embodiment of the device according to  FIGS. 1   a - c.    
         [0046]      FIG. 3   a  shows a laptop L that includes a cover D. Reference numeral  1   a  labels an LCD display of cover D which corresponds to the carrier device. Reference numeral  10   a  labels the back-side cover plate of cover D which corresponds to plate-shaped device  10  depicted in  FIGS. 1   a - c . Reference numeral  2  labels one of a plurality of piezoelectric strips  2  that are installed between LCD display  1  and back-side cover plate  10   a , e.g., in a configuration as shown in  FIG. 1   a . Using this configuration, it is possible to design rear-side cover  10   a  of cover D of laptop L as a base speaker. Via this feature, it is possible to increase the low-frequency components of the sound emitted by a laptop or similar computers, which the known installed loudspeakers of mobile electrical devices are typically unable to do. 
         [0047]    In terms of the second functionality, i.e., damping operation, vibrations of plate-shaped device  10  that are detected may be damped accordingly by activating piezoelectric strips  2 . This operation is advantageously associated with the sensor operation which detects vibrations of this type via deformation of piezoelectric strips  2 . Individual strips  2  may therefore function as sensor elements or as actuator elements, in a time-dependent manner. However, it is also possible for a group of piezoelectric strips  2  to function exclusively as sensor elements, and for a further group to function exclusively as actuator elements. Sound absorbing applications are, e.g., air/space travel applications, and motor vehicle applications, e.g., absorbing wind noise on windshields, or isolating sound produced during flight in the walls of aircraft. 
         [0048]    It is also possible to design a device that operates exclusively as a sensor, e.g., to monitor vibrations in buildings or vehicles. 
         [0049]      FIG. 4  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a second embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c.    
         [0050]    In the embodiment shown in  FIG. 4 , the offset or displacement S 1  at coupling points  3   c   1 ,  3   c   2 ,  3   c   3  of plate-shaped device  10  may be attained via the phase-opposed superposition of three piezoelectric strips  2   a ,  2   b ,  2   c . To this end, a rigid intermediate plate Z 1  and Z 2  is situated between strips  2   a ,  2   b  and  2   b ,  2   c , respectively. Strips  2   a ,  2   b ,  2   c  are continuous strips that are composed of a large number of strip segments  2  according to  FIG. 1   c . Ends E 1 , E 2  of the segments of strip  2   a  are connected to carrier device  1 , and middle regions M of segments  2  of strip device  2   a  are connected to first intermediate plate Z 1 . Ends E 1 , E 2  of segments  2  of second strip device  2   b  are connected to first intermediate plate Z 1 , and middle regions M of segments  2  of second strip device  2   b  are connected to second intermediate plate Z 2 . Ends E 1 , E 2  of elements  2  of third strip device  2   c  are connected to second intermediate plate Z 2 , and middle regions M of segments  2  of third strip device  2   c  are connected to plate-shaped device  10 , i.e., at coupling points  3   c   1 ,  3   c   2 ,  3   c   3 . 
         [0051]    Particular ends E 1 , E 2  of strip elements  2  of strip  2   b  are located above corresponding middle regions M of strip elements  2  of strip  2   a . Particular ends E 1 , E 2  of strip elements  2  of strip  2   c  are located above corresponding middle regions M of strip elements  2  of strip  2   b . As a result, phase opposition is attained, which causes an increase in displacement. 
         [0052]    For the rest, the design of strips  2   a ,  2   b ,  2   c  or segments  2  corresponds to the design described in conjuction with  FIG. 1   c.    
         [0053]      FIG. 5  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a third embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c.    
         [0054]    In the embodiment presented in  FIG. 5 , the stiffness of middle region M of the strips is increased by connecting a plurality of strips  2   d ,  2   e ,  2   f  in parallel by interconnecting them at end regions E 1  or E 2 , where they are also connected at points  3   a ,  3   b  to carrier device  1 . The force of the actuator is also increased as a result. 
         [0055]      FIG. 6  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a fourth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c.    
         [0056]    In the fourth embodiment, as shown in  FIG. 6 , a first and second piezoelectric strip  2   a ′,  2   b ′ are provided, which substantially have the same design as piezoelectric strip  2  in the first embodiment. The only difference is that piezoelectric ceramic layer  20  and electrode layers  21  adjacent thereto do not extend to end regions E 1 , E 2  or E 1 ′, E 2 ′, but rather terminate at a distance therefrom. 
         [0057]    As shown in  FIG. 7 , first end region E 1  of first strip  2   a ′, and first end region E 1 ′ of second strip  2   b ′ are connected (e.g., bonded) in regions  3   a  and  3   b , respectively, to surface OF of carrier device  1 . Second end region E 2 , E 2 ′ is connected to plate-shaped device  10  which is not depicted here. This design has the advantage that substantially stiffer, inflexible piezoceramics may be incorporated in the structure. 
         [0058]      FIG. 7  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a fifth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c.    
         [0059]    In the embodiment depicted in  FIG. 7 , two curved piezoelectric strips  2   g ,  2   h  are connected at their first end E 1  to the substrate at points  3   a  and  3   b , while they are connected at their particular second end E 2  to each other and to plate-shaped device  10  which is not shown here. This results in a decrease in the tension in strips  2   g ,  2   h  since the radius of curvature is greater. 
         [0060]      FIG. 8  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a sixth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c.    
         [0061]    In the embodiment depicted in  FIG. 8 , strip  2  according to  FIG. 1   c  is divided into two strips  2   i ,  2   j . Strips  2   i ,  2   j  have an S shape, one end E 1 ′ of which is connected at points  3   a ,  3   b  to carrier device  1 , and the other end E 2 ′ of which is connected at points  3   d  or  3   e  to plate-shaped device  10 . A design of this type likewise lowers the flexural load on the piezoelectric strips  2   i ,  2   j . Piezoelectric strips  2   i ,  2   j  are activated by control device C in such a manner that horizontal force components are eliminated. 
         [0062]      FIG. 9  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a seventh embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   a.    
         [0063]    In the embodiment depicted in  FIG. 9 , three continuous strips are bonded in parallel via a plurality of segments  2  located one after the other (see  FIG. 4 ) to a surface OF of a carrier device  1 ′. Piezoelectric strips  2   k ,  2   l  have varying widths. They may exert different forces on plate-shaped device  10  (which is not depicted) at different locations. In this embodiment, piezoelectric strip  2   m  functions merely as a sensor, and may have a constant or variable width. 
         [0064]    Not shown in the depiction presented in  FIG. 9  is the coupling of plate-shaped device  10  which should be realized as indicated in  FIG. 1   c . Since the force of piezoelectric strips  2   k ,  2   l ,  2   m  that acts in the normal direction relative to surface OF is proportional to its width, it is possible in this embodiment to vary the force in the longitudinal direction of strips  2   k ,  2   l ,  2   m , thereby making it possible to induce certain types of vibration of plate-shaped device  10 . 
         [0065]      FIG. 10  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to an eighth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c.    
         [0066]    In the embodiment depicted in  FIG. 10 , a long piezoelectric strip  2   n  is connected, e.g., bonded, at its ends E 1 , E 2  in regions  3   a  and  3   b  to carrier device  1 . Piezoelectric strip  2   n  is a longer piezoelectric strip than piezoelectric strip  2  depicted in  FIG. 1   c . A guide plate FP is provided above piezoelectric strip  2   n , which includes an opening  0  that has a predetermined diameter d around middle region M of strip  2   n . Strip  2   n  may move in the direction of arrow S 1 , which is perpendicular to surface OF of carrier device  1 , only in this region of opening O having diameter d. This is not possible in the edge regions of strip  2   n , i.e., in the contact region of guide plate FP, since guide plate FP holds strip  2   n  against surface OF of substrate  1 . Given the longer length of strip  2   n , strip  2   n  is capable of undergoing greater displacement than strip  2  since the change in length of strip  2   n  is proportional to its length. Due to the presence of guide plate FP, the displacement may be deliberately relocated to middle region M, and strip  2   n  is prevented from buckling outside of middle region M located within opening O. In addition, guide plate FP may be used as a heat sink for heat that is produced via the piezoelectrically induced motions. As indicated by dashed lines, guide plate FP is connected, e.g., to carrier device  1  via a mechanical connection device V. A connection device V of this type may be realized, e.g., using screws or bonding. In any case, connecting device V must ensure that guide plate FP may not move perpendicularly to surface OF of carrier device  1 . A further possible function of guide plate FP is an electrode function for piezoelectric strip  2   n . In this case, the corresponding insulations of strip  2   n  must be interrupted at suitable points. 
         [0067]      FIG. 11  shows a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a ninth embodiment of the present invention. 
         [0068]      FIG. 11  shows a surface waveform OW of carrier device  10 , which may be generated, e.g., by a device according to  FIG. 10 , if piezoelectric strips  2  are situated in concentric circles on carrier device  1 , in which case the longitudinal extension of piezoelectric strips  2  extends radially. 
         [0069]      FIG. 12  is a schematic depiction of a device for the excitation and/or damping and/or detection of structural vibrations of a plate-shaped device using a piezoelectric strip device according to a tenth embodiment of the present invention, in a sectional view that is analogous to  FIG. 1   c.    
         [0070]    In the embodiment depicted in  FIG. 12 , in contrast to the embodiment explained with reference to  FIG. 1   c , plate-shaped device  10  is a printed circuit board on which an electronic element  100 , which should be protected from vibrations, is mounted. To accomplish this, control device C depicted in  FIG. 12  performs a vibration decoupling operation. Strip  2 , which is depicted, and strips  2 , which are not shown, are used as actuators. One or more strips  2 , which are not shown, are used as sensors. 
         [0071]    To support the decoupling of vibrations, an additional damping device DE, e.g., in the form of a related elastomer element, is provided between carrier device  1  and plate-shaped device  10 . Damping device DE is in direct contact with carrier device  1  and plate-shaped device  10 . 
         [0072]    Although the present invention has been explained above with reference to preferred embodiments, it is not limited thereto, and may be realized in another manner. 
         [0073]    Although certain geometries of the strip configuration and the arrangement of the strips relative to the plate-shaped device were illustrated with reference to the above-described embodiments, the present invention is not limited thereto, but rather may basically be depicted in any geometrical configuration. Likewise, the structure of the piezoelectric strips may deviate from the structure that is shown, e.g., it may include a plurality of piezoelectric ceramic layers having corresponding electrode layers. 
         [0074]    Finally, the applications mentioned above are presented as examples only, and may be used, of course, on other plate-shaped devices, such as housing plates, reinforcement plates, etc.