Bending transducer as actuator, bending transducer as sensor, and bending transducer system

Abstract

The present invention describes a bending transducer operating as an actuator, comprising a deflectable element, a microelectromechanical transducer extending along a centroid fiber of the deflectable element, the microelectromechanical transducer deflecting the deflectable element in a first direction when a first electrical signal is applied; and a second microelectromechanical transducer extending along the centroid fiber, the second microelectromechanical transducer deflecting the deflectable element in a second direction opposite to the first direction when a second electrical signal is applied; wherein the centroid fiber is located between the sides of the first and second microelectromechanical transducers facing away from each other; and an electrical control element configured to change the first electrical signal and the second electrical signal according to an input signal, so that the change of the first electrical signal and the change of the second electrical signal depend on the electrical input signal, and the phases of the first and second electrical signals are offset relative to each other. The present invention also proposes a bending transducer operating as a sensor.

Description

Technical Field

[0001] The present invention relates to a bending transducer, and use thereof as an actuator or a sensor, and a bending transducer system. Background Art

[0002] Micromechanical devices (MEMS) are needed to convert electrical signals into mechanical effects, ie in the case of actuators, or to convert mechanical effects into electrical signals, ie in the case of sensors. For the purposes of this application, "effect" means, for example, the performance of work, and the application of an associated deflection or bending moment.

[0003] The linearity of the relationship between the electrical signal and the mechanical effect (transmission characteristic) of a microelectromechanical component is often subject to high demands. This applies, for example, to the use of such microelectromechanical components in microphones or loudspeakers. Nonlinearities in the transmission characteristic adversely affect the accuracy with which the microelectromechanical component can fulfill its intended function and must be corrected by complex control in the case of actuators or by complex signal processing in the case of sensors.

[0004] For example, non-linearities in the transmission characteristics of micromechanical sound transducers (ie loudspeakers or microphones) lead to high distortion factors and have to be corrected by additional use of microprocessors or signal processing.

[0005] In summary, there are practical applications such as microspeakers, in which a linear relationship between the level of the applied signal voltage and the amplitude of the mechanical effect (i.e., the work to be performed) produced by the device is crucial. At the same time, the spectral composition of the output signal (in the case of a loudspeaker, air-borne sound) should be equivalent to the spectral composition of the input signal, which corresponds to a low distortion factor. The linear range depends on the amplitude and frequency and should be as large as possible. In this regard, it is necessary to change the sensitivity and frequency by changing the (electrical) operating parameters without significantly changing the linearity. For the purposes of this application, sensitivity means the relationship between the change in the effect and the change in the signal. Previous design implementations of MEMS devices with improved linearity of transmission characteristics are based on MEMS technology with unfavorable high voltage requirements in a limited dynamic range of the structure (relative to pull-in instability) and therefore a limited frequency range, which is not suitable for mobile applications. An illustrative reference is made to document US 97 834 08 B2.

[0006] WO 2095185 A1 describes how to design a MEMS device with high performance and low power consumption, but does not describe possible measures for improving and adjusting linearity. For the purpose of increasing the bending radius or increasing the drive efficiency with the same bending characteristics, DE 10 2015 206 774 A1 proposes a bending transducer system consisting of two bending transducers separated by a neutral fiber. The cavity formed in this process is intended to have only a positive effect on the bending characteristics. Measures for improving and adjusting linearity are not disclosed. Summary of the invention

[0007] It is therefore an object of the present invention to provide a bending transducer, and its use as an actuator or sensor, and a system of such bending transducers, which show an improved and adjustable linearity with the same or comparable efficiency.

[0008] This object is solved by the subject-matter of the independent claims.

[0009] The core concept of the present application is that a bending transducer used as an actuator can provide improved and adjustable linearity at comparable performance when the bending transducer comprises a deflectable element having a first microelectromechanical transducer (hereinafter referred to as MEMS transducer) and a second MEMS transducer, the first MEMS transducer extending along a centroid fiber of the deflectable element and the second MEMS transducer extending along a centroid fiber, the centroid fiber being located at least between remote edges or between sides of the MEMS transducers facing away from each other, or even between the MEMS transducers, and when a first or second electrical signal is applied to the first or second MEMS transducer, and when a change of the first and second electrical signals is performed according to the electrical input signal, the deflectable element is deflected in opposite directions so that the phases of the first and second electrical signals are shifted relative to each other. The phase shift can be between 0.001° and 240° (inclusive), or even between 60° and 200° (inclusive) or 180°. This embodiment allows to obtain advantages in terms of linearity that would otherwise be possible using the three-electrode principle, and to obtain a symmetric control without performance problems. According to the invention, by means of the control, a large linear range with high dynamics, i.e. a large amplitude range, can be obtained over a large frequency range. Similarly, part of the core concept of the present application has been the recognition that a bending transducer used as a sensor can obtain improved and adjustable linearity at comparable performance when the bending transducer is equipped with a deflectable element, wherein the centroid fiber of the deflectable element is still located between the opposite sides of the first and second MEMS transducers, and once the deflectable element is deformed, the electrical signal output at the terminals of the transducer is used to generate the output signal so that the change of the output signal depends on the difference between the change of the first electrical signal at the first transducer and the change of the second electrical signal at the second transducer. On the one hand, the linearity can be optimized during load changes, and on the other hand, the sensitivity and selectivity (in this case the resonant frequency) can be adapted application-specifically in order to maximize the linear dynamic range (in this case the amplitude) and the linear frequency band.

[0010] According to an embodiment, the first and second MEMS transducers are each plate capacitor subdivided into segments along the longitudinal direction of the deflectable element and therefore also subdivided along the centroid fiber by fixing the electrodes of the respective plate capacitors to each other between the segments. In this way, the deflection of the bending transducer can be large relative to the distance between the two electrodes. The centroid fiber can be located at least between the sides of the MEMS transducers facing away from each other, that is, between the remote electrodes of the MEMS transducers or the opposite sides of the electrodes placed at a distance from each other; or even between the remote electrodes of the MEMS transducers; or between the proximal electrodes of the MEMS transducers or the opposite sides of the electrodes away from each other; or even between the MEMS transducers, that is, the sides facing the proximal electrodes of the MEMS transducers. In some of these embodiments, the electrodes of the respective plate capacitors are arranged in the segments in an interdigitated manner, so that the projection of one electrode is projected in the gap between the corresponding projection of the other electrode, and vice versa. This improves performance and sensitivity.

[0011] In an embodiment using a bending transducer as an actuator, the electric drive is arranged to apply a first bias voltage and a combination of a first signal portion according to an input signal as a first electrical signal to the first MEMS transducer, and / or to apply a second bias voltage and a combination of a second signal portion according to the input signal as a second electrical signal to the second MEMS transducer. The electrical signal may be, for example, a voltage or a current. The control element of the MEMS transducer used as an actuator may consist of two control elements with a bias voltage U0 and a variable signal voltage U1. signal The electrical control element is thus configured to perform a change in the first and second electrical signals with different amplitudes to compensate for an asymmetric load on the deflectable element. An asymmetric load is, for example, a structural asymmetry of the microelectromechanical transducer and / or an asymmetric force (such as a pressure difference) acting on the deflectable element. Similarly, a bending transducer used as a sensor can compensate for an asymmetric load on the deflectable element. The control element of the bending transducer used as a sensor can be configured to apply a bias to the first MEMS transducer and / or to the second MEMS transducer. According to an embodiment, the bias or multiple biases of the bending transducer are set in such a way that the centroid fiber of the deflectable element is not deflected in the absence of external mechanical influences on the deflectable element, and in the case of a bending transducer used as an actuator, it is not deflected in the absence of a signal portion that depends on the input signal.

[0012] According to an embodiment, the bending transducer is therefore provided with a control configured to apply a bias voltage to the first MEMS transducer and / or to the second MEMS transducer, whereby the effective spring stiffness of the bending transducer, and / or the sensitivity of the bending transducer and / or the resonant frequency of the bending transducer can be adjusted by adjusting the bias voltage at the first MEMS transducer and / or at the second MEMS transducer. The effective spring stiffness of the MEMS transducer varies relative to its mechanical spring stiffness with a fixed voltage or level of bias. This embodiment makes it possible to adjust the linearity.

[0013] According to an embodiment, the electrical control of the bending transducer used as an actuator has a feedback loop in order to dynamically compensate the effects of asymmetrical loads, i.e. during operation with alternating loads, by means of a suitable feedback loop with a sensor. Alternatively, active network components such as transistors, operational amplifiers etc. can be used to adjust the electrical network parameters such as power consumption, impedance, voltage, current, which are relevant to the respective load situation. Overall, the feedback system means a dynamically improved linearity of the transfer characteristic.

[0014] According to an embodiment, the bending transducer system includes a plurality of bending transducers, wherein the bending transducers are matched to the size setting of the MEMS transducers. In other words, the bending transducers can be configured identically. The effective spring stiffness, and / or the resonant frequency and / or the sensitivity of the bending transducers can be individually adjusted via the bias at the first and / or second MEMS transducers of most of the bending transducers. One advantage is that the resonant frequency or the dynamic behavior below the resonant frequency can be individually adjusted by the bias depending on the application. In general, since each bending transducer is only responsible for a specific frequency band, improved linearity can be achieved, and performance deviations between frequency bands can be compensated by assigning different numbers of bending transducers to the frequency bands. In other words, by controlling the respective biases in different proportions, the configured bending transducers are associated exactly with the respective frequency bands to which the bending transducers are subsequently sensitive. The proportion can compensate for the following: the bending transducer is more sensitive / effective for one frequency band than it is for another frequency band, or is less sensitive / effective.

[0015] Some embodiments relate to a curved transducer system having a circuit configured to spectrally split a total input signal into multiple input signals for multiple curved transducers or to spectrally synthesize a total output signal from multiple output signals of multiple curved transducers. The circuit may be partly or completely part of a control. One aspect of the spectral splitting of the total input signal or the spectral synthesis of the output signals is the discovery that the linearity of a micro-electromechanical transducer can be increased by configuring several curved transducers. The arrangement may be designed in such a way that the effects of the individual curved transducers are added so that the individual curved transducers of the arrangement operate only in a portion of the dynamic range (e.g., deflection). This improves the linearity of the overall system.

[0016] Some embodiments relate to a bending transducer configured to operate as an actuator or as a sensor, and circuits designed to operate the bending transducer as an actuator or as a sensor. This configuration is space-saving because the same bending transducer can be used as a sensor or as an actuator depending on the application.

[0017] Some embodiments relate to a bending transducer system having a plurality of bending transducers and a circuit configured to control a first portion of the total amount of the bending transducers as actuators and a second portion of the total amount of the bending transducers as sensors. The division into two subsets may be static or may be performed dynamically, depending on a control signal. The bending transducers may be controlled to act both as actuators and as sensors in one time interval, or as sensors in a first time interval and as actuators in a second time interval, or as actuators in a first time interval and as sensors in a second time interval. The number of sensors or actuators may be adjusted via static or dynamic control signals, depending on the application area. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The preferred embodiment of the present application will be explained in more detail below with reference to the accompanying drawings. It shows:

[0019] FIG. 1 is a diagram showing a spring characteristic curve of a deformable element of a micro-electromechanical device;

[0020] Fig. 2 is a schematic diagram of the dual electrode principle;

[0021] FIG3 is a diagram showing the relationship between the deflection and the signal voltage of an actuator according to the two-electrode principle;

[0022] Figure 4a Schematic diagram of a variation of the push-pull principle;

[0023] Fig. 4b is a schematic diagram of a variation of the push-pull principle;

[0024] FIG5 is a diagram showing the relationship between the electrical signal strength and the mechanical deformation according to the three-electrode principle;

[0025] Figure 6 Schematic diagram of a deformable element with active layers attached on both sides;

[0026] Figure 7a A block diagram of a symmetrical overall system and a schematic diagram of an embodiment;

[0027] Figure 7b Figure 7a A diagram of the transmission characteristics of the embodiment shown in ;

[0028] Figure 8 Schematic diagram of the abstraction principle of the control element;

[0029] Fig. 9 Schematic diagram of a bending transducer as an actuator;

[0030] Fig.10 Schematic diagram of a bending transducer as a sensor;

[0031] Fig.11 Block diagram of load regulation;

[0032] Fig.12 Block diagram of dynamic load adjustment;

[0033] Fig.13 Schematic diagram of a curved transducer system with a spectrum splitting circuit;

[0034] Fig.14 Schematic diagram of a bending transducer system with a spectrum synthesis circuit;

[0035] Fig.15 Schematic diagram of a bending transducer system with bias adjustment;

[0036] Fig.16 A schematic diagram of a bending transducer operable as an actuator and / or as a sensor, with circuitry configured to operate the bending transducer as an actuator and / or as a sensor;

[0037] Fig.17 Schematic diagram of a bending transducer system including circuitry configured to operate the bending transducer individually as an actuator and / or as a sensor;

[0038] Fig.18a Schematic diagram of a symmetric electrostatic cantilever that can be deflected in two directions and the electrical biasing of the cantilever at the external electrode;

[0039] Fig.18b Schematic diagram of a symmetric electrostatic cantilever that can be deflected in two directions and the electrical biasing of the cantilever with the inner electrode;

[0040] Fig.18c Schematic diagram of a symmetric electrostatic cantilever that can be deflected in two directions and the electrical biasing of the cantilever with the inner electrode;

[0041] Fig.18d Schematic diagram of a symmetric electrostatic cantilever that can be deflected in two directions as well as cantilevered;

[0042] Fig.19a Schematic diagram of a cross section of an electrostatically deflectable and cantilevered cantilever with inner and outer electrodes;

[0043] Fig.19b Schematic diagram of a cross section of an electrostatically deflectable and cantilevered cantilever with tilted electrodes;

[0044] Fig.19c Schematic diagram of a cross section of an electrostatically deflectable and cantilevered arm with comb electrodes;

[0045] Fig.20a Schematic diagram of a deflectable element, wherein only a half section with a multilayer electrode structure is shown;

[0046] Fig.20b remove Fig.20a A schematic diagram of a deflectable element having a central cavity other than

[0047] Fig.20c Schematic diagram of a deflectable element, wherein Fig.20a In contrast, the proximal electrodes are configured to be plane-parallel and not convexly expanded;

[0048] Fig.21a Schematic diagram of half section, with Fig.19c Compared to comb electrodes having a convex segment configuration for increasing the depositable electric field energy;

[0049] Figure 21b Schematic diagram of half section, with Fig.19c Compared to comb electrodes having a configuration for increasing depositable electric field energy using concave segments;

[0050] Fig. 22 Schematic diagram of a cantilevered deflectable element, with Fig.19a Compared to an asymmetric configuration with two MEMS transducers. DETAILED DESCRIPTION

[0051] Before the embodiments of the present invention will be described below, it is first explained what considerations led the inventor to these embodiments. Of course, in the course of these explanations, reference has been made to the features of the embodiments described below, which features should also be transferable to these embodiments.

[0052] The nonlinearity of MEMS components has two origins: the electromechanical construction and its operating principle, the so-called static nonlinearity, and the dynamic behavior of the device, the so-called dynamic nonlinearity. Dynamic nonlinearity is a result of mechanical and / or electrical design features. Dynamic nonlinearities such as intermodulation, operating point shifts, subharmonic resonances are often a result of static nonlinearities. Correction of existing dynamic nonlinearities is technically complex, if it is practical at all in a given case.

[0053] The MEMS device of the type considered here has at least one deformable element. The force required for the deformation can be characterized by a spring characteristic curve. Strictly linear transmission behavior requires that the corresponding spring characteristic curve at the selected operating point is strictly linear over the entire selected dynamic range.

[0054] FIG. 1 shows a spring characteristic curve of a deformable element. If the relevant deformable element is a beam, a plate or a plate segment, the course of the associated spring characteristic for a greater deflection is not linear, but partially or completely progressive or decreasing. Alternatively, a combination may also occur. Decreasing in a first time interval and progressive in a second time interval. Progressive or decreasing spring characteristics generally produce unfavorable nonlinear transmission characteristics. For the operation of the MEMS device, an operating point such as A, B, C or D can be selected at the corresponding spring characteristic curve, around which the deformable element performs its movement within a specific maximum amplitude or dynamic range. This will apply to a relatively large dynamic range at operating point A, for example. At operating point B, the possible dynamic range for linear operation is limited by the start of the progressive or decreasing process of the spring characteristic curve. Selecting operating point C or D produces a MEMS device with high sensitivity, i.e., the spring characteristic curve is particularly steep here. This increase in change has a higher quantitative level here and therefore has a negative effect on the dynamic range.

[0055] FIG2 shows a MEMS device based on the two-electrode principle. A capacitively operated MEMS device according to the two-electrode principle comprises at least one deformable or movable element, a so-called transducer or shuttle 1810, configured as an electrode and whose spring characteristic curve is illustrated in FIG1 , and another fixed counter-electrode, a so-called stator 1820. When a voltage 1830 is applied, the electrostatic attraction generated between the electrodes pulls the transducer 1810 towards the stator 1820. The attraction is independent of the sign of the applied voltage 1830. When used as a sensor, the device changes its capacitance when the transducer 1810 is mechanically influenced. In this case, the capacitance change is used to generate an output signal.

[0056] FIG3 shows a typical relationship between electrical signal strength or voltage and mechanical deformation or deflection for a MEMS device according to the two-electrode principle as illustrated in FIG2. In order to operate a capacitive MEMS device according to the two-electrode principle, by applying a bias voltage U DC To select the operating point (e.g. A, B or C). For a bending transducer used as an actuator, a signal voltage U can be superimposed on this bias voltage. AC In the case of a bending transducer used as a sensor, the mechanical action enables a movement and generates a corresponding signal voltage around the operating point. The absolute sum of the bias voltage and the signal voltage should not exceed a critical voltage amount, the so-called pull-in voltage U pull-in This critical voltage value is defined by the fact that for voltages above this limit, the balance of mechanical and electrical forces required for the intended function is unstable and therefore irrelevant.

[0057] Operating point A requires the bias voltage to be equal to zero. Although the spring characteristic curve as illustrated in FIG1 is actually linear at this operating point, the signal voltage moves in only one direction without regard to its sign and thus causes strongly nonlinear transmission behavior (such as frequency doubling) or a dynamically induced shift of the operating point.

[0058] The operating point B enables a change in the direction of movement of the deformable element as a function of the sign of the signal voltage. The course of the assigned spring characteristic curve also enables a linear transmission behavior with a selected bias voltage to be sufficiently small; however, the maximum possible deflection or dynamic range in linear operation is severely limited by the low maximum possible deflection with negative signal voltages.

[0059] The operating point C enables the change of the movement direction of the deformable element to vary with the sign change of the signal voltage and allows a substantially large dynamic range. However, near the operating point, both the associated spring characteristic curve and the deflection voltage characteristic are strongly non-linear.

[0060] Therefore, design-related nonlinearities are characteristic for the two-electrode principle. This means that the mechanical movement performed as intended by the device does not follow the electrical input signal in proportion. This nonlinearity can essentially only be reduced within narrow limits by applying a time-constant bias as operating point, combined with unfavorable restrictions on the maximum admissible amplitude of the mechanical movement. Another problem is that the favorable sensitivity increase of the device has an unfavorable effect on the linearity compared to the change of the input signal by increasing the constant electrical bias or the operating point. Another problem of the device mentioned is that the nonlinearity given here produces even harmonics, as a result of which the geometric position of the zero point of the mechanical vibration performed by the device according to its intended purpose is dynamically shifted. The distinction in this case also applies to a similar situation when using capacitive MEMS devices as sensors according to the two-electrode principle.

[0061] Additionally, there are capacitive MEMS devices based on the three-electrode principle. Figure 4a 4b illustrates a MEMS device based on the three-electrode principle or push-pull principle, which has at least one movable or deformable element or transducer 2010 and one stationary element or stator 2020. The three-electrode configuration is controlled by a fixed bias voltage U B Operation and use of variable signal voltage U S Additional operation. The electrode configuration allows the electric control 2030 to make the converter 2010 deflectable in two opposite directions relative to the stator 2020 by the resulting electrostatic force in this way. To achieve this, the stator 2020 and the converter 2010 are provided with a total of at least three electrodes with different functions. The three-electrode principle improves the linear behavior to a minimum with its symmetrical design, but has disadvantages such as the risk of pull-in and disadvantages in terms of low performance.

[0062] FIG. 5 shows a schematic diagram for symmetric control based on Figure 4a and the typical relationship between the electrical signal strength or voltage and the mechanical deformation or deflection of a MEMS device of the three-electrode principle illustrated in 4b. In the case of symmetrical control, the static position of the converter (i.e., at zero signal voltage) is independent of the electrical bias voltage. At the operating point, the deformable element is mechanically in a static position, i.e., not deformed. This means that both the characteristics of the spring characteristic curve and the relationship between the deflection and the signal voltage at the operating point and for the maximum dynamic range are linear.

[0063] In the following, the basic structures of bending transducers and bending transducer systems as well as their basic operating modes will be described based on schematic illustrations.

[0064] Figure 6 A schematic perspective view of a deformable or deflectable element 1300 with active layers or MEMS transducers 141b and 142b attached on both sides is shown. When a first electrical signal is applied to the MEMS transducer 141b, the deflectable element 1300 deflects in a first direction 161b. Similarly, when a second electrical signal is applied to the MEMS transducer 142b, the deflectable element 1300 deflects in a second direction 162b opposite to the first direction.

[0065] Improved linearity of the transmission characteristics of the deflectable element can be achieved through the symmetrical configuration of the deformable element 1300, and the symmetrical configuration and symmetrical arrangement of the dual piezoelectric chip structures 141b, 142b on the deformable element 1300 combined with symmetrical electrical control.

[0066] Figure 7aA corresponding embodiment 1020 for the case of a symmetrical load 1019 is shown in FIG. 10 and a block diagram 1010. The block diagram 1010 consists of three blocks: a symmetrical control 1013, a symmetrical MEMS transducer 1016, and a symmetrical load 1019. The embodiment 1020 illustrates a symmetrical deflectable element 110n with symmetrical MEMS transducers 1016a, 1016b and a symmetrical control 1013a consisting of two cascaded network loops. The symmetry should be configured such that the transmission characteristics of the total system (consisting of the control, MEMS transducer, and load) obey the symmetry principle, i.e., if the sign of the signal voltage is opposite, the deflection of the deformable element is essentially the same amount, but with opposite sign results.

[0067] This symmetry leads to the suppression of mechanical even harmonics. For the electrostatic transducer considered in this article, the amplitude of the third harmonic is always smaller than the amplitude of the second harmonic. Therefore, the symmetry also reduces the amplitude of the third harmonic. Overall, this means low harmonic distortion (THD), that is, significantly improved linearity.

[0068] Figure 7b Show Figure 7a The transmission characteristic of the embodiment shown in . For practical operation, the dashed branch of the curve shown is relevant. The principle of symmetry is thus achieved by this embodiment.

[0069] Symmetrical control 1013a use Figure 8 The principle of abstraction shown in . Figure 7a The control element 1013a in Figure 8 The circuit diagram is shown as two loops: loop I and loop II. Loop I is coupled to the first MEMS transducer 1016a or the dual piezoelectric chip I, and loop II is coupled to the second MEMS transducer 1016b or the dual piezoelectric chip II. The first and second electrical signals of loop I and loop II respectively have a bias voltage U 01 Or U 02 And the signal voltage U signal1 Or U Signal2 Cascade network loop. In the case of symmetry, the bias voltage U of loop I and loop II 01 and U 02 are equal, and the signal voltage U of loop I and loop II signal1 and U Signal2 The quantities are respectively equal, but the operations are performed with opposite signs.

[0070] The following example uses the above findings and considerations and is able to provide improved linearity of transfer characteristics with low voltage requirements and high performance.

[0071] Fig. 9A bending transducer operating as an actuator is shown. The same bending transducer is shown with reference numeral 100. Figure 6 As described in more detail in FIG. 1 , the bending transducer 100 includes a deflectable element 110 and a Figure 8 An electrical control member 120 according to the principle shown in . The deflectable element 110 includes a first MEMS transducer 141 spaced apart from and extending along the centroid fiber 130 of the deflectable element 110, and a second MEMS transducer 142 spaced apart from and extending along the centroid fiber 130. The centroid fiber 130 defines all points of the deflectable element 110 having a centroid in a cutting plane transverse to the longitudinal direction x. In other words, the centroid fiber defines a path in the member, which is composed of or connected by a number of points generated by the centroids of multiple consecutive cross-sectional areas of the deflectable element. In addition, examples 190 and 191 show two fibers spaced apart from the centroid fiber 130 in opposite directions. When the voltage U s1 The first electrical signal (at Fig. 9 ) is applied to the MEMS transducer 141, the deflectable element 110 deflects in the first direction 161. Similarly, when the second electrical signal (also illustrated here as a voltage U S2 ) is applied to the MEMS transducer 142, the deflectable element 110 deflects in a second direction 162 opposite to the first direction. In other words, the MEMS transducer 141, when activated, causes a deflection in the direction 161 by applying a voltage, through a transverse strain of the fiber 190 of the component 110 located in front of the centroid fiber 130 in the direction 161, and a simultaneous contraction of the fiber 191 located behind the centroid fiber 130 in the direction 161. This occurs through a phase shift in the control during the first time interval described later. During the second time interval, the other MEMS transducer (i.e., 142), when activated, causes a deflection of the element 110 in the direction 162 by applying a voltage, through a transverse strain of the fiber 191 and a contraction of the fiber 190. Here, as an example, a case where strain occurs once the corresponding signal is applied to each MEMS transducer 141, 142 is shown, but other cases are also possible. For example Fig. 9As shown in , according to an embodiment of the present application, the first MEMS transducer 141 and the second MEMS transducer 142 can each be designed as a plate capacitor segmented along the longitudinal direction x of the deflectable element 130. The electrodes 151 to 154 of the respective plate capacitors 141, 142 are fixed to be insulated from each other between the segments 169 at the segment boundaries 170. A spacer layer can be provided between the electrodes 151 to 154 of the respective plate capacitors 141, 142, and the spacer layer is laterally constructed to form a spacer at the segment boundaries 170, which fixes the electrodes of the respective MEMS transducers to each other. If a voltage is applied between the electrode 151 and the electrode 152 or between the electrode 153 and the electrode 154, a strain or alternatively (in the case of a specific configuration of the segments) a contraction occurs and thus the described deflection occurs. Further details can be found in WO2012095185.

[0072] The electric control element 120 is adapted to E Change the first electrical signal U S1 and the second electrical signal U S2 , so that the first electrical signal U S1 The change of the second electrical signal U S2 The change depends on the electrical input signal U E , and the first electrical signal U S1 and the second electrical signal U S2 The phases of the phases are offset relative to each other, such as by 180° out of phase or by a phase shift between 0.001° and 240° (including both ends) or between 60° and 200°.

[0073] By means of the possibility of a symmetrical arrangement of the deformable element 110, for example, the centroid fiber 130 forms its plane of symmetry, and by means of Figure 7a The symmetrical control illustrated in , in interaction with a symmetrical electrical control, is possible to achieve high efficiency with high linearity at the same time. In the following, measures are described which will further improve the achievement of this object.

[0074] Fig.10 A bending transducer 300 having a deflectable element 110a as shown in FIG. 6 is shown operating as a sensor and used in Figure 8 The circuit 320 of the principle presented in FIG. can be used with Fig. 9 The deflectable element 110a of the bending transducer 300 is constructed similarly to the deflectable element 110 of the bending transducer 100 used as an actuator in FIG. Fig. 9 The deformation of the deflectable element 110a can be caused by a first or second electrical signal (here again illustrated as a voltage U S1 , U S2) is determined at the first MEMS transducer 141a or the second MEMS transducer 142a. In the case where the MEMS transducers 141a, 142a are configured as plate capacitors, a signal is generated, for example, as a voltage at the same electrode. The circuit 320 is configured to generate a signal from the first electrical signal U S1 and the second electrical signal U S2 Generate output signal U out , so that the output signal U out The change depends on the first electrical signal U S1 The change of the second electrical signal U S2 The difference in changes. Fig. 9 In the embodiment of the present invention, the possibility of a symmetrical configuration of the deformable element 110 such that, for example, the centroid fiber 130 forms its symmetry plane, and the like Figure 7a The symmetrical electrical pre-connection 1013a shown in , allows high performance to be achieved while achieving high linearity. In the following, measures to improve the achievement of this object are also described in the present case of operating a bending transducer as a sensor.

[0075] Although this is not specifically indicated in the following description, it should be mentioned that the deflectable element 110 or 110a may be a cantilevered element (e.g. a cantilevered beam) having a clamp at one end of the deflectable element along the aforementioned segment direction x. In the figures, the clamp is sometimes indicated by hatching on the left.

[0076] When used as intended, the deformable element 110, 110a of the bending transducer is subjected to external forces or external loads, such as due to its own weight or, in the case of piston movement in a micropump, which may be asymmetric with respect to the direction of movement of the deformable element. Fig.11 A block diagram of a symmetrical overall system 1100 with an asymmetrical load 1130 is shown. The block diagram of the symmetrical overall system 1100 comprises the following three blocks: a control 1110 with adapted symmetry, a deformable element 1120 with adapted symmetry and an asymmetrical load 1130.

[0077] By public Fig. 9 The necessary symmetry of the overall system consisting of the control element 120, the deformable element 110, 110a and the load in FIG. 1 can be achieved by a specific adaptation of the transducer configuration and / or its electrical control to the asymmetric load 1130. Figure 7a As indicated in , symmetry of the individual parts of the overall system is not necessary. The symmetry of the bending transducer can be achieved by adapting to the asymmetric load 1130 ( Fig.11 ) is realized by the asymmetric dual piezoelectric chip structure of the bending transducer, that is, for example Fig. 9 and Fig.10Symmetrical adaptation of the bimorph structures 141, 141a, 142, 142a can be achieved, among other things, by varying the electrode thickness or the electrode spacing between the two sides of the symmetry line of the deformable elements 110, 110a. Fig. 22 However, symmetrical adaptation can also take place by adapting the control 120 or the circuit 320 ( Fig.10 ), for example by introducing a compensating electrical impedance in loop I or loop II or in respective parts of the control member assigned to the MEMS transducer 141, 141a, 142, 142a. Finally, the effective spring stiffness k' of the deformable element 110, 110a varies with respect to its mechanical spring stiffness k as a function of the level of the fixed voltage U0.

[0078]

[0079] Therefore, the system can be realized by selecting different fixed voltages U in loop I and loop II. 01 and U 02 and is adapted to the asymmetric load 1130, i.e., by Fig. 9 In the case of the control element 120 applying different bias voltages to the MEMS transducer units 141 and 142, or in Fig.10 In the case of , different bias voltages are provided by the circuit 320. Measures for symmetry adaptation at the level of the control and the deflectable elements 110, 110a can be configured such that the symmetry principle of the overall system is implemented within practically relevant limits.

[0080] In other words, Fig. 9 and Fig.10 In the embodiment of the present invention, the circuit 320 and the control member 120 can be configured to operate the MEMS transducers 141 / 141a and / or the MEMS transducers 142 / 142a, respectively, using different bias voltages to compensate for the asymmetry of the load so as to compensate for the asymmetric load on the deflectable element 110 / 110a, which is caused by operation and is constant, for example. If, for example, the asymmetric load causes the deflectable element to deflect in a static position in the direction 162, then the MEMS transducer causing the deflection in the opposite direction is operated using a higher bias voltage.

[0081] and Fig.11 In contrast, the adaptation of the transducer symmetry and / or its electrical control 120 and circuit 320, respectively, to the asymmetrical load 1130 can also be achieved dynamically, i.e. during operation with alternating loads, by means of suitable sensors and feedback systems. The relevant electrical network parameters, such as impedance, voltage, current, etc., are adjusted to the respective load situation by means of active network components, such as transistors, operational amplifiers, etc. Fig.12A block diagram of a symmetrical overall system with a feedback system 1200 is shown. The block diagram shows three consecutive blocks and a feedback system 1240. The three blocks are: a control 1210 with dynamically adapted symmetry, a deformable element 1220 with dynamically adapted symmetry, and an asymmetric load 1230. The feedback 1240 links the asymmetric load 1230 to the deformable element 1220 and to the control 1210.

[0082] In other words, this could be the case: measuring Fig. 9 and Fig.10 The asymmetric load on the deflectable element 110 / 110a in the embodiment of the present invention is measured. The measurement can be performed externally and fed to the control 120 or to the circuit 320 so that the latter adjusts the bias voltage of the MEMS transducer 141 / 141a and / or the MEMS transducer 142 / 142a or the difference between the two bias voltages accordingly. The measurement of the asymmetric load can also be performed by an internal sensor. The control 120 or the circuit 320 can detect the asymmetric load on the deflectable element itself via the mechanical to electrical conversion of the MEMS transducer 141 / 142.

[0083] An important aspect is that dynamically induced shifts of the rest position or operating point can be prevented by the symmetry-induced suppression of even harmonics. Such dynamic shifts of the operating point would otherwise change the system characteristics when used as an actuator or sensor depending on the spectral composition of the input signal or stimulus and would therefore be particularly disadvantageous.

[0084] By increasing the linearity of the system, the occurrence of subharmonic resonances is also suppressed. Subharmonic resonances usually occur when a nonlinear bending transducer 100 is operated as an actuator with a broadband signal control 120. They limit the technically usable frequency range to fractions of the resonant frequency, typically 1 / 2, 1 / 3, 1 / 5, etc., since the output of the control electronics 120 is effectively short-circuited when it is passed via the frequency axis. Subharmonic resonances can usually only be reduced imperfectly by an active feedback system 1200, since cross-modulation phenomena also occur with nonlinearity. In addition, the active feedback system 1200 increases the system cost. The suppression of subharmonic resonances, due to an unnecessary increase in system damping or power dissipation, reduces the drive efficiency and is particularly disadvantageous for mobile applications. In contrast, the linearization of the deformable element is particularly advantageous.

[0085] Another aspect is the discovery that the sensitivity, ie the steepness of its transfer function, can be adjusted by changing the fixed voltage U0 using the control 120 and the circuit 320 and the design of the MEMS transducers 141, 141a, 142, 142a. The sensitivity is proportional to the square of the fixed voltage U0:

[0086]

[0087] Thus, for example, by increasing the fixed voltage U0, the signal voltage U required to achieve maximum deflection can be reduced. signal amplitude without any noticeable loss of linearity.

[0088] This aspect is crucial for the use of the bending transducer 300 as the actuator 100, since the electrical reactive power required for operation is proportional to the signal voltage U signal It is proportional to the square of and can be greatly reduced by increasing the bias voltage U0.

[0089]

[0090] The high reactive power consumption generates high electrical losses in the control electronics 120 and is incompatible with the use of bending transducers in mobile applications. This aspect has clear advantages compared to previous technologies, such as capacitive actuators, magnetic actuators or piezoelectric actuators.

[0091] This is of particular importance for the use of bending transducers as sensors, since the sensitivity of the sensor can be greatly increased and, for example, the signal-to-noise ratio of a microphone implemented with such a bending transducer can be significantly improved.

[0092] This aspect is crucial for the use of bending transducers as actuators and as sensors, since by a good choice of the signal voltage amplitude the costs of the necessary control electronics 120 or circuit 320 can be significantly reduced. For example, the production of CMOS electronics with voltages <12 V is particularly cost-effective. Signal voltages <5 V correspond to the TTL standard which is widely used for low-cost electronic components. Signal voltages <1.3 V can be controlled directly, i.e. without additional driver circuits, via the electrical outputs of modern signal processors.

[0093] The sensitivity of the deformable element 110, 110a, i.e. the tangent slope of the transfer function at zero, can be improved by design measures. The decisive factor here is that the sensitivity is proportional to the ratio of the maximum electrostatic energy that can be deposited in the bi-piezoelectric chip structure 141, 141a, 142, 142a to the elastic deformation energy deposited in the deformable element 110, 110a at maximum deflection.

[0094]

[0095] This allows increasing the sensitivity of the bending transducer (otherwise equal) by increasing the maximum electrostatic energy deposited in the bi-piezoelectric chip structure 141, 141a, 142, 142a and / or by reducing the deformation energy required for the maximum deflection. Thus, the fixed voltage U0 required to adjust a certain sensitivity can be reduced.

[0096] The maximum electrostatic energy that can be deposited in the dual piezoelectric chip structures 141, 141a, 142, 142a can be increased by cleverly selecting the electrode geometry and configuration. Fig.19c The interdigitated configuration in the form of a comb structure shown in can be arranged between electrodes. In particular, Fig.19c It is shown how the projections of the electrodes 151 and 152 of the MEMS transducer 141 (a) interlock, thereby increasing the capacity and thus also the depositable electrostatic energy. The same is also shown for the other MEMS transducer 142 / 142a.

[0097] It is also possible that the maximum elastic energy that can be deposited in the deformable element 110 / 110a can be reduced by a clever choice of mechanical design.

[0098] For example, depending on the principle of the support structure, the solid volume that is deformed during deflection can be minimized.

[0099] For bending transducers 100, 300 in which the deformable element 110, 110a is a cantilever beam and its intended direction of movement is in the plane of the wafer, the maximum beam length, and therefore the lowest possible resonant frequency, is limited by the vertical pull-in. The spring stiffness of the deformable element 110, 110a perpendicular to the direction of movement plays a decisive role in the vertical pull-in, while the spring stiffness in the direction of movement plays a decisive role in the resonant frequency. The relationship between the effective spring stiffness and the fixed voltage U0 described above mainly applies to the spring stiffness in the direction of movement. This discovery makes it possible to further reduce the lowest possible resonant frequency of a given deformable element 110, 110a by increasing the fixed voltage relative to the mechanically determined limit.

[0100] The effective spring stiffness k' of the deformable element 110, 110a can be reduced by fixing the voltage U0 relative to the mechanical spring stiffness k':

[0101]

[0102] With this knowledge, an electronically variable bending transducer 100 / 300 or a bending transducer system can be realized, in which the resonant frequency or the dynamic behavior can be adjusted below the resonant frequency via a fixed voltage U0 depending on the application.

[0103] In the following, some embodiments based on the cooperation of several bending transducers will be described.

[0104] Fig.13 FIG. 2 shows a bending transducer system 210 including a plurality of bending transducers 100a-n and a splitting circuit 220. The number n may be 2 or greater than 2. Each of the plurality of bending transducers 100a-n is used as an actuator, and as shown in FIG. Fig. 9 , but differ in spectral efficiency and sensitivity. This can be achieved as described below: Fig.13 , indicating that different spectral efficiencies are achieved by different sizing of the deflectable elements. The splitting circuit 220 is coupled to the bending transducers 100a-n individually and is adapted to convert the total input signal U E 230 spectrally splits into a plurality of input signals U for a plurality of bending transducers 100a-n Ea -U Ed 240a-n, so that each curved transducer 100a-n receives a spectral portion of the input signal 230 for which its sensitivity and linearity are high, or suitable for the frequency band associated with the corresponding curved transducer. The splitting circuit is optional and may also be omitted. This may be accomplished by using, for example, Fig.13 The linearity can be increased by using several bending transducers 100a-n as shown in FIG. The mechanical effects of the bending transducers 100a-n are added together so that the individual bending transducers of the arrangement can only operate in a portion of the dynamic range or deflection. A single bending transducer with comparable effect, i.e., an arrangement with only one deformable element and the same efficiency, would otherwise require a high degree of precision and measurement to achieve the same linearity.

[0105] Fig.14 A bending transducer system 410 and a circuit 420 are shown with a plurality of bending transducers 300a-n. The number n may be 2 or greater than 2. Each bending transducer 300a-n operates as a sensor to Fig.10 The circuit 420 is coupled to the bending transducers 300a-n to generate a plurality of output signals U from the plurality of bending transducers 300a-n. out,a -U out,n Spectrally constitute the total output signal U out As in Fig.13 In the example, the spectral efficiency or sensitivity of the bending transducers is different from each other. Fig.14As indicated, this can be achieved by the fact that the dimensions are different from each other. Since each bending transducer 100a-n is configured for a specific spectral portion or frequency band where its sensitivity and linearity are high, it is possible to increase the linearity and thereby the effect of the bending transducer. A single bending transducer of comparable effect, i.e. an arrangement with only one deformable element and of the same efficiency, would otherwise require a high degree of precision and measurement to achieve the same linearity.

[0106] Fig.15 A bending transducer system having a plurality of bending transducers 730a-n and a circuit for bias adjustment, namely 720, is shown. Fig.15 Bending transducers (indicated by reference numerals 730a-n in the figure to indicate that they) can be used as actuators, such as Fig.13 A bending transducer 100a-n, or a bending transducer operating as a sensor, such as Fig.14 The bending transducer 300a-n. Fig.13 and Fig.14 different, Fig.15 The bent transducers 730a-n are shown in the following manner: their dimensions do not differ. However, it is possible to change the spectral efficiency or sensitivity of the bent transducers 730a-n. This is done by the bias adjustment circuit 720. The bias adjustment circuit is able to individually adjust the aforementioned bias used to operate the MEMS transducer in the deflectable element of the bent transducers 730a-n. This adjustment thus allows the spectral efficiency or sensitivity of the bent transducers 730a-n to be individualized or to be responsible for different frequency bands. For example, in addition to the frequency decomposition circuit 220 or also in Fig.13 as well as Fig.14 In addition to the combined circuit 400 in the system, the bias adjustment circuit 720 can also be used to perform fine adjustment of the bending transducer here. Fig.15 Circuit 220 / 420 may also be provided.

[0107] It is possible to provide a bending transducer that can operate as a sensor or as an actuator. Fig.16 This bending transducer 840 is shown. The bending transducer 840, which can be operated as a sensor and / or as an actuator, is provided with a circuit 820 configured to operate the bending transducer 840 as a sensor and / or as an actuator. The bending transducer includes Fig. 9 The deflectable element 110 and / or Fig.10 The deflectable element 110a in the embodiment is constructed similarly to the deflectable element 110b and is configured to be dependent on the input signal U in To change the first electrical signal U S1 Or the second electrical signal U S2The circuit 830, or the first electrical signal U S1 And from the second electrical signal U S2 Generate output signal U out The circuit 820 is coupled to the circuit 830 and is configured to operate the bending transducer 840 as a sensor and / or as an actuator.

[0108] Even those bending transducers whose use as actuators or sensors has not yet been defined, e.g. Fig.16 The bending transducers representatively described in can also be combined into a system. Fig.17 Such a system is shown.

[0109] Fig.17 9 and 920. The bending transducer system includes a plurality of bending transducers 840a-n. The bending transducers 840a-n can be connected to Fig.16 The bending transducer 840 in FIG. 1 is similarly constructed and can be operated as an actuator and / or a sensor. The circuit 920 is coupled to the bending transducers individually and is configured to select a first portion of the total number of bending transducers as actuators and a second portion of the total number of bending transducers as sensors, wherein the subsets are allocated based on the control signal S. In other words, the circuit 920 sends a signal to the bending transducer 840 to the bending transducer 840. Fig.16 The circuit 830 issues a command to take over the function as a control circuit or the function as an electrical circuit.

[0110] As already mentioned above, the system shown consisting of several bending transducers enables improved linearity to be achieved. Several bending transducers are used so that their mechanical effects add up, so that the individual bending transducers of each arrangement or system, for example, only have to operate within a small part of the total dynamic range of the system. A geometrically equivalent actuator with only one deformable element and the same functionality would have otherwise required higher precision and more measurements.

[0111] Other embodiments of bending transducers and deflectable elements are described below.

[0112] exist Fig.18a-d shows again the structure of a device based on a bending transducer and operating as an actuator based on a cantilever beam. An insulating separation layer 170' and conductive materials 151 and 154 are applied on both sides of the conductive beam 1201. For example, the insulating separation layer 170' can be constructed laterally by sacrificial layer technology so that thin cavities 1304 and 1404 are formed between the electrodes 1201 and 151 or between the electrodes 1201 and 154 in each of the segments 169, wherein the deflectable element is segmented along the longitudinal direction x and the insulating spacer 170 is maintained at the segment boundaries. The cavity has the thickness of the dielectric sacrificial layer and thus defines the plate spacing of the capacitor. If a voltage is applied between the electrodes 1201 and 151 or between the electrodes 1201 and 154, the force in the y direction of the electrostatic field causes a lateral strain on the surface of the beam in the x direction. Due to the surface strain, the beam 1201 deflects. If a regular lateral geometry is used, the surface strain is approximately constant and forms a spherical deformation profile.

[0113] The wire is made in such a way that the DC voltage U B is applied to the external electrodes 151 and 154, and the AC signal voltage U S , such as an audio signal, is applied to the middle electrode or beam. The outer electrodes 151 and 154 are provided with an electrical bias. The AC signal voltage U S The amplitude and electrical bias voltage U B Equal to or preferably less than the electrical bias voltage U B The highest potential in the system must be chosen in an economically justifiable manner and in compliance with applicable directives and standards. Due to the electrical bias of the external electrodes, the curvature of the beam follows the signal AC voltage U S . AC signal voltage U S The positive half-wave of y causes beam 1201 to bend in the negative y-direction. The negative half-wave causes beam 1201 to bend in the positive y-direction. Fig.18a -d shows other variations of electrical contacts.

[0114] Fig.18a shows that each external electrode is provided with a DC voltage, but compared to Fig.18b have opposite potentials.

[0115] Fig.18c and Fig.18d A variation with electrical biasing of the inner electrode is shown. A signal voltage is applied to the outer electrode.

[0116] Rather than a bias being electrically applied to the outer or inner electrode, there may instead be a permanent polarization of the outer or inner electrode as an electret (eg silicon dioxide).A current source may be used instead of the voltage source shown in the previous figures.

[0117] Fig.19a-c shows other embodiments of deflectable elements or alternative configurations of electrodes of a MEMS transducer, where controls are not shown for clarity. Fig.18a -c figure number and basic description.

[0118] Fig.18a -d indicates that the component to be bent or the GRO or the carrier 1201 itself can act as an electrode. Fig.19a A possible configuration is shown according to which the individual proximal electrodes of each plate capacitor are instead provided directly on the surface or upper and lower sides of the support 1201 facing the plate capacitor. Here, 152 and 153 are inner or proximal electrodes and 151 and 154 are outer or remote electrodes.

[0119] The surface topography of the electrode can be Fig.19b In addition, electrodes of different shapes (e.g., dome-shaped electrodes) are possible. In order to further increase the capacitor area and thus the electrostatic energy that can be deposited, comb-shaped electrodes (e.g., Fig.19c ) is possible.

[0120] The component to be bent (eg a beam) can be cantilevered or clamped on both sides.

[0121] Fig.20a 21a-c and 21a-b show other possible embodiments of the deflectable element. In each of these figures a half segment 169 is shown. The other half can each define a shape symmetrically. The bending transducer or deflectable element consists of an even number of segments 169 formed in a continuous manner, for example in the longitudinal direction x. In the illustrations only the surface topography is shown, without showing the distinction between the electrode and the insulating separation layer.

[0122] In particular, Fig.20a The following situation is shown: each segment 169 is formed so that the electrodes 151 and 154 of the two electrodes 151 and 154 facing each other via the mass core fiber 130 each bulge forward through the mass core fiber 130, and the spaces 1304 and 1404 respectively separate the electrodes 151 and 154 from the other electrodes 152 and 153, and have an approximately constant thickness in the direction of the mass core fiber 130. In other words, the internal electrodes 152 and 153 in the segment 169 are also bent away from the mass core fiber 130. Fig.20a In the case of the deflectable element between the inner electrode 152 and the inner electrode 153 is integrally connected, ie there is no cavity. Fig.20b Show Fig.20a A modification of an embodiment in which cavity 1500 is formed between electrode 152 and electrode 153. Fig.20cA variation is shown in which the internal electrodes 152 and 153 do not protrude outwardly from the centroid fiber 130, but remain parallel to the centroid fiber 130, so that the cavity 1304 / 1404 separating these electrodes 152, 153 from the corresponding remote electrodes 151 / 154 has a varying thickness in the longitudinal direction x, in particular increasing from the segment boundary 170 towards the center of the segment.

[0123] Fig.20a -c shows a configuration in which remote electrodes 151 and 154 are multi-layered. This means that Fig.20a and 20b In the configuration of , the deflectable elements in each segment are configured in such a way that they bulge between the segment boundaries 170 in both directions away from the centroid fiber 130, i.e. become thicker towards the center of the segment, so that the proximal electrodes 151 and 152 also bulge accordingly. According to the proximal electrodes 152 and 153, the two layers 1601, 1602 forming the electrode 151 and the electrode layers 1603 and 1604 forming the electrode 151 extend on the sides of the proximal electrodes 152 and 153, respectively, facing away from the centroid fiber 130. Between the electrode pairs 1601 and 1602 and 1603 and 1604, respectively, a cavity of constant thickness along the longitudinal direction x is formed again. The layers 1601 to 1602 on the one hand and 1603 and 1604 on the other hand can be provided with the same potential. Alternatively, it is possible to modify each MEMS transducer to be equipped with three electrodes 152 , 1601 and 1602 or 153 , 1603 and 1604 . Fig.20c It means that the cavity between the pair of layers 1601 and 1602 or 1603 and 1604 may have a thickness that varies along the longitudinal direction x, ie is greatest in the center of the segment.

[0124] Fig.21a and Figure 21b Show Fig.19c The difference is that the remote electrodes 151 and 154 in each segment are respectively concavely or convexly projecting, that is, in accordance with Fig.21a In the convex case, it is most convex at the center of the segment, and Figure 21b In the case of , the electrodes 151 to 154 protrude closest to the proximal electrodes 152 and 153, while the projections of the electrodes 151 to 154 respectively mesh with each other or project into each other in a comb-like manner.

[0125] Compared to the surface topologies shown so far, Figures 20a to 21b The surface configuration shown allows a greater amount of energy to be deposited and therefore a greater deflection of the actuator. Fig.20aThe dual electrode structure of the remote electrodes of -c and the concave-convex curved configuration of the remote electrodes with an interdigitated finger design of the electrodes can achieve advantages with respect to a high amount of depositable energy and at the same time with respect to the topological structure suitable for the material in order to achieve the maximum possible deflection.

[0126] Fig. 22 An embodiment of an asymmetric actuator 100 or a bending transducer 100 having an asymmetric configuration of a deflectable element 110 is disclosed, which is cantilevered. The electrodes 151 and 152 of the first MEMS transducer are thicker than the electrodes 153 and 154 of the second MEMS transducer 141 142. This also increases the distance between the electrodes 151 and 152. Advantageously, the asymmetric structure results in an asymmetric effect of the actuator. Fig. 22 The possibility of structural asymmetries being able to compensate for external asymmetries is thus illustrated.

[0127] Thus, the above-described embodiments make it possible to design a native transducer that operates particularly linearly in a wide dynamic and frequency range. According to the embodiments, only a moderate voltage is required. At the same time, it has a high performance level.

[0128] The above embodiments are merely illustrative of the principles of the present disclosure. It should be understood that modifications and variations to the configurations and details described herein will be clear to those skilled in the art. Therefore, the present invention is intended to be limited only by the scope of the attached patent claims and is not limited by the specific details presented by the specification and the explanation of the embodiments herein.

Claims

1. A bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840a-n) as an actuator having a deflectable element (110, 110a-n, 1120, 1220, 1300), comprising a first micro-electromechanical transducer (141, 141ab, 1016a) extending along a centroid fiber (130, 130a) of the deflectable element, the first micro-electromechanical transducer deflecting the deflectable element (110, 110a-n, 1120, 1220, 1300) in a first direction (161, 161b) when a first electrical signal is applied, and a second micro-electromechanical transducer (142, 142a-b, 1016b) extending along the centroid fiber (130, 130a), the second micro-electromechanical transducer causing the deflectable element to deflect in a second direction (162, 162b) opposite to the first direction when a second electrical signal is applied, The centroid fiber (130, 130a) is located between the sides of the first micro-electromechanical transducer and the second micro-electromechanical transducer (141, 141a-b, 142, 142a-b, 1016a, 1016b) facing away from each other, and An electrical control element is configured to change the first electrical signal and the second electrical signal according to an input signal, so that the change of the first electrical signal and the change of the second electrical signal depend on the input signal, and the phases of the first electrical signal and the second electrical signal are offset relative to each other by a phase shift, wherein the phase shift is between 0.001°-240°, including 0.001° and 240°.

2. The bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) according to claim 1, wherein the first microelectromechanical transducer (141, 141a-b, 1016a) and the second microelectromechanical transducer (142, 142a-b, 1016b) include plate capacitors segmented (169) along the longitudinal direction of the deflectable element.

3. The bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) of claim 2, wherein electrodes (151-154, 151a-154a) of the first plate capacitor and the second plate capacitor are configured as interdigital.

4. The bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) according to claim 2, wherein the electrical control element is configured to apply a combination of a first bias voltage and a first signal portion depending on the input signal as the first electrical signal to the first micro-electro-mechanical transducer (141, 141a-b, 1016a), and / or to apply a combination of a second bias voltage and a second signal portion depending on the input signal as the second electrical signal to the second micro-electro-mechanical transducer (142, 142a-b, 1016b).

5. A bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) according to claim 4, wherein the first bias and / or the second bias are adjusted so that the centroid fiber (130, 130a) of the deflectable element is not deflected in the absence of a signal portion depending on the input signal and in the absence of external mechanical influences on the deflectable element (110, 110a-n, 1120, 1220, 1300).

6. The bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) according to claim 4, wherein the electrical control is configured so that the spring stiffness of the bending transducer, and / or the sensitivity of the bending transducer, and / or the resonant frequency of the bending transducer are adjustable by adjusting a bias voltage or multiple bias voltages at the first micro-electro-mechanical transducer and / or the second micro-electro-mechanical transducer (141, 141a-b, 142, 142a-b, 1016a, 1016b).

7. The bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) of claim 1, wherein the electrical control is configured to perform changes in the first electrical signal and the second electrical signal with different amplitudes to compensate for an asymmetric load (1130, 1230) on the deflectable element (110, 110a-n, 1120, 1220, 1300).

8. The bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) according to claim 7, wherein the asymmetric load (1130, 1230) is a structural asymmetry of the first microelectromechanical transducer and / or the second microelectromechanical transducer (141, 141a-b, 142, 142a-b, 1016a, 1016b) and / or an asymmetric force acting on the deflectable element (110, 110a-n, 1120, 1220, 1300).

9. The bending transducer (100, 100a-n, 300, 300a-n, 730a-n, 840, 840an) of claim 7, wherein the electrical control comprises a feedback loop (1240) for dynamically compensating for the effects of the asymmetric load (1130, 1230).

10. A bending transducer system (210, 410, 710, 910), comprising a plurality of bending transducers (100, 100a-n, 300, 300a-n, 730a-n, 840, 840a-n) according to claim 1, wherein the bending transducers (100, 100a-n, 300, 300a-n, 730a-n, 840, 840a-n) are matched in size relative to the first micro-electromechanical transducer and / or the second micro-electromechanical transducer (141, 141a-b, 142, 142a-b, 1016a, 1016b), wherein the plurality of bending transducers (100, 100a-n, 300, 300a-n, 730a-n, 840, 840a-n) are matched in size relative to the first micro-electromechanical transducer and / or the second micro-electromechanical transducer (141, 141a-b, 142, 142a-b, 1016a, 1016b). The spring stiffness and / or resonant frequency and / or sensitivity of the first and / or second microelectromechanical bending transducers (141, 141a-b, 142, 142a-b, 1016a, 1016b) are individually adjustable via a bias voltage to the first and / or second microelectromechanical bending transducers (141, 141a-b, 142, 142a-b, 1016a, 1016b).

11. A curved transducer system (210, 410, 710, 910), comprising a plurality of curved transducers according to claim 1 and a splitting circuit (220), the splitting circuit being configured to spectrally split a total input signal into a plurality of input signals for the plurality of curved transducers.

12. A bending transducer (300, 300a-n, 730a-n) as a sensor having a deflectable element (110, 110a-n, 1120, 1220, 1300), comprising: a first micro-electromechanical transducer (141, 141a-b, 1016a) extending along the centroid fiber (130, 130a) of the deflectable element, capable of determining a first electrical signal at a terminal end of the first micro-electromechanical transducer in response to a deformation of the deflectable element (110, 110a-n, 1120, 1220, 1300), a second micro-electromechanical transducer (142, 142a-b, 1016b) extending along the centroid fiber (130, 130a) of the deflectable element, capable of determining a second electrical signal at a terminal end of the second micro-electromechanical transducer in response to a deformation of the deflectable element (110, 110a-n, 1120, 1220, 1300), The centroid fiber (130, 130a) is located between the sides of the first and second micro-electro-mechanical transducers (141, 141a-b, 142, 142a-b, 1016a, 1016b) facing away from each other, and An electrical circuit (320) is configured to generate an output signal (U) from the first electrical signal and the second electrical signal. out ,U outa -U outd , U out , U out1 -U out3 ), so that the output signal (U out , U outa -U outd , U out , U out1 -U out3 ) changes depending on the difference between the change of the first electrical signal and the change of the second electrical signal; Wherein the electrical circuit is configured to generate an output signal such that an asymmetric load on the deflectable element is compensated.

13. The bending transducer of claim 12, wherein the first microelectromechanical transducer and the second microelectromechanical transducer comprise plate capacitors segmented along a longitudinal direction of the deflectable element.

14. The bending transducer of claim 13, wherein electrodes of the first plate capacitor and the second plate capacitor are configured as interdigital. 15 . The bending transducer of claim 13 , wherein the electrical circuit is configured to apply a bias voltage to the first micro-electro-mechanical transducer and / or to the second micro-electro-mechanical transducer.

16. A bending transducer according to claim 15, wherein the bias voltage or multiple bias voltages are adjusted so that the centroid fiber of the deflectable element is not deflected in the absence of external mechanical influences on the deflectable element.

17. The bending transducer of claim 12, wherein the asymmetric load is a structural asymmetry of the first micro-electro-mechanical transducer and / or the second micro-electro-mechanical transducer, and / or an asymmetric force acting on the deflectable element.

18. The bending transducer according to claim 12, comprising a control element configured to apply a bias voltage to the first micro-electromechanical transducer and / or to the second micro-electromechanical transducer to adjust a spring stiffness of the bending transducer and / or a sensitivity of the bending transducer and / or a resonant frequency of the bending transducer.

19. The bending transducer according to claim 12, comprising: an electrical control element configured to change the first electrical signal and the second electrical signal according to an input signal, so that a change in the first electrical signal and a change in the second electrical signal depend on the input signal, and phases of the first electrical signal and the second electrical signal are shifted relative to each other; as well as A circuit (820) is configured to operate the bending transducer as a sensor and / or as an actuator.

20. A bending transducer system comprising a plurality of bending transducers according to claim 12, wherein the bending transducers are matched relative to the size setting of the first micro-electromechanical transducer and / or the second micro-electromechanical transducer, and wherein the spring stiffness and / or the resonant frequency and / or the sensitivity of the plurality of bending transducers are individually adjustable via a bias voltage to the first micro-electromechanical transducer and / or the second micro-electromechanical transducer.

21. A bending transducer system comprising a plurality of bending transducers according to claim 12 and a circuit (420) configured to spectrally compose a total output signal from a plurality of output signals of the plurality of bending transducers.

22. A bending transducer system comprising a plurality of bending transducers according to claim 1 or 12, and a circuit (920) configured to cause a first portion of the total amount of the bending transducers to operate as actuators and to cause a second portion of the total amount of the bending transducers to operate as sensors, the division into subsets depending on a control signal.

23. A bending transducer system comprising a plurality of bending transducers according to claim 1 or 12, wherein the bending transducer is controlled to act as both an actuator and a sensor in a time interval, or the bending transducer is controlled to act as a sensor in a first time interval and as an actuator in a second time interval, or the bending transducer is controlled to act as an actuator in a first time interval and as a sensor in a second time interval.

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