COUPLING DEVICE FOR COUPLING VIBRATION SYSTEMS

Description

[0001] The present invention relates to coupling devices for coupling vibration systems. In particular, the invention relates to micro-electromechanical components, such as inertial sensors, especially yaw rate sensors, with multiple vibration systems that are mechanically coupled.

[0002] Modern micro-electro-mechanical systems (MEMS), such as inertial sensors, especially gyroscopes, often have multiple oscillation systems oscillating in counter-phase. This is sometimes used to symmetrically distribute the forces and torques acting on the oscillating masses present in the oscillation systems, so that the system is free of external forces and torques, at least on average over time.

[0003] For example, it's known to guide two masses in opposite directions along a line. Various coupling mechanisms are known for such "dual-mass sensors," which ensure a force- and torque-free oscillation over time.

[0004] A problem arises, however, when multiple oscillation systems are to be used that oscillate in the same direction but are arranged parallel to one another rather than one behind the other. This is particularly the case for so-called "quad mass sensors," i.e., angular rate sensors that have four oscillating masses. These are paired to form two dual-mass sensors, with each of the dual-mass sensors itself being able to be coupled in a known manner. In addition to coupling the oscillating masses of the individual dual-mass sensors in push-pull motion, the masses of the two dual-mass sensors should also always be moved in push-pull motion, as this minimizes the overall forces and torques. Furthermore, the movement of all masses should often be as one-dimensional as possible.

[0005] From DE 103 00 682 A1, US 2009 / 071247 A1 or US 2005 / 066726 A, vibration systems coupled by means of bending beam springs are known, which are symmetrically constructed and can vibrate in antiphase.

[0006] State-of-the-art solutions to this problem often couple the two dual-mass sensors using lever or rocker designs. However, such designs have the disadvantage that the ends of the levers, due to their rigid design, do not follow straight paths, but circular paths. The use of such levers thus pulls the coupled oscillation systems away from their desired linear motion, particularly for particularly preferred larger deflections of the oscillation systems. Lever devices for coupling oscillation systems therefore systematically lead to an unwanted deflection of the oscillating masses from a purely linear motion and can also impede the movement of the masses in push-pull mode. These systematic errors lead to a deterioration of the measurement results, which can only be compensated for in a complex manner.

[0007] The object of the present invention is therefore to provide a coupling device for coupling at least two oscillation systems, with which a counter-rotating movement of the oscillation systems can be reliably guided. A further object of the invention is to provide micro-electromechanical components, such as inertial / angular rate sensors, that have such coupled oscillation systems. This object is achieved by the subject matter of the claims.

[0008] A coupling device for coupling a plurality of vibration systems mounted above a substrate such that they can vibrate along a first direction and are offset from one another in a second direction perpendicular to the first direction can comprise a cantilever spring that is bendable in the first direction and can be connected to the vibration systems. Connections of the cantilever spring to the vibration systems are arranged between at least two connection points of the cantilever spring to the substrate such that a deflection of the cantilever spring caused by movements of the vibration systems leads to vibration of the cantilever spring with vibration antinodes in the region of the connections of the cantilever spring to the vibration systems.

[0009] This ensures that vibration systems arranged adjacently in the y-direction and coupled by means of the coupling device are stabilized in their counter-phase movement once an vibration of the bending beam spring has been excited by this, since the vibration systems are connected to the bending beam in the region of oppositely vibrating antinodes. The connections are optimally arranged at the points of maximum deflection. For the excitation of a vibration mode with, for example, two antinodes, it can be helpful if two vibration systems oscillate in counter-phase at the natural frequency of the corresponding vibration mode. If the system is generalized to a plurality of vibration systems that are coupled via the bending beam spring, an arrangement of connections to the bending beam spring and / or a vibration excitation in which an antinode is created in the region of each connection is advantageous.In this way, vibration systems can be effectively coupled to one another in such a way that a counter-rotating motion can be supported by neighboring vibration systems. Furthermore, by connecting only each antinode of the cantilever spring to a vibration system, a co-rotating vibration can be achieved, or, if the vibration systems are irregularly distributed, a mixed counter-rotating and co-rotating vibration can be achieved.

[0010] A micro-electromechanical component according to the invention, preferably an inertial sensor, more preferably a yaw rate sensor for measuring a rotation of the yaw rate sensor, comprises the coupling device as described above and the plurality of oscillation systems. According to a first solution according to the invention, the number of oscillation systems is N and the length of the cantilever spring between two connection points to the substrate is L. The oscillation system n (n=1, ..., N) is then connected to the cantilever spring at (2n-1) L / 2N. This simplifies the formation of N oscillation antinodes and thus the push-pull coupling.

[0011] Alternatively, the coupling device can couple at least a first vibration system and a second vibration system to each other. The cantilever spring extends along the second direction and can be connected to the substrate at at least three connection points: to the first vibration system between a pair of adjacent connection points, and to the second vibration system between the other pair of adjacent connection points. The coupling device is suitable for guiding opposing vibrations of the first vibration system and the second vibration system in a coupled manner along the first direction.

[0012] In particular, a micro-electromechanical component, such as an inertial sensor or a yaw rate sensor for measuring a rotation of the yaw rate sensor or of an object connected to the yaw rate sensor, can comprise the coupling device described above as well as the first oscillation system and the second oscillation system. The coupling device is connected to the substrate at three connection points and is connected to the first oscillation system between one pair of adjacent connection points and to the second oscillation system between the other pair of adjacent connection points.

[0013] A micro-electro-mechanical component, such as a yaw-rate sensor, therefore has two oscillating systems that are required for the micro-electro-mechanical component to function, e.g., for determining the sensor's yaw rate. These systems can, in principle, be designed in any way, as long as they can oscillate in opposite directions in a first direction and are arranged next to each other with an offset in a second, perpendicular direction. The motion lines of the oscillating systems can be offset or even tilted relative to each other. The two oscillating systems can, for example, be dual-mass yaw-rate sensors combined to form a quad-mass sensor.

[0014] In contrast to the prior art, no rigid lever is used to connect the two vibration systems, but rather a coupling device with a cantilever spring. This is connected to the sensor substrate at three points. The connection to the vibration systems is located between these connection points, preferably midway between the connection points.

[0015] If a vibration in the first direction is now excited in one (or both) of the vibration systems, the part of the cantilever spring connected to the vibration system is pulled accordingly in the first direction, while remaining essentially stationary at the two connection points to the substrate. Due to the one-dimensional deflectability of the cantilever spring, the area connected to the other vibration system is moved in the opposite direction, or a corresponding movement excited in the vibration system is supported and stabilized. The coupling device is therefore suitable for guiding the vibration systems in a coupled manner.

[0016] The decisive factor here is the use of the cantilever spring as a coupling element, since the cantilever spring's deformability in the first direction enables a linear movement without a circular component. This is not possible with a lever mechanism as known from the prior art. For this reason, the cantilever spring also allows for larger deflections of the oscillation systems than a lever mechanism, since the deviation from linear movement becomes more pronounced when using levers the greater the lever movement. This limits the technically feasible deflection of the coupled oscillation systems, a limitation that fundamentally does not apply to the cantilever spring.

[0017] The use of a suitable cantilever spring connected to the substrate makes it possible to achieve a coupling between two oscillation systems that does not result in a deviation of the oscillation systems from the intended opposing motion. This increases the reliability of the sensor. Furthermore, the oscillation systems can oscillate with a larger amplitude, which increases the signal strength of the measured signals. This, in turn, leads to more sensitive sensors.

[0018] When the first oscillation system and the second oscillation system oscillate in opposite directions along the first direction, the coupling device can force them to move in counter-phase, preferably parallel, motion. Thus, a strictly counter-directional motion is supported or induced. Furthermore, motion components deviating from the first direction can be reduced or eliminated by the deflection of the cantilever spring. The coupling device can thus force the two oscillation systems onto parallel motion paths. These measures can further improve the oscillation behavior, making the micro-electro-mechanical component more reliable.

[0019] The coupling device can force the first and second oscillation systems to oscillate with equal amplitude and opposite directions. This ensures that the coupled oscillation systems are as force- and torque-free as possible, since spring forces and torques occurring in the first oscillation system compensate for spring forces and torques occurring in the second oscillation system when both oscillations oscillate exactly in counter-phase, i.e., with the same amplitude but opposite deflection along the first direction.

[0020] The coupling device according to a second solution according to the invention has a first, a second, and a third torsion spring element. The first torsion spring element connects a first end of the cantilever spring, the second torsion spring element connects the center of the cantilever spring, and the third torsion spring element connects a second end of the cantilever spring to the substrate. Furthermore, the first oscillation system is connected to the cantilever spring in the middle between the first and second torsion spring elements, and the second oscillation system is connected to the cantilever spring in the middle between the second and third torsion spring elements. As a result, upon opposing deflection of the first and second oscillation systems along the first direction, the second eigenmode of the cantilever spring forms as the first eigenmode of the coupling device and forces the first and second oscillation systems to move in opposite directions, preferably in parallel.

[0021] By using torsion spring elements for the connection between the cantilever spring and the substrate, the cantilever spring is rotatably mounted at the connection points. This allows the cantilever spring to bend more strongly at the connection points in the direction of the deflection of the adjacent oscillating system. The cantilever spring therefore takes on an S-shape for the coupling, as it is (essentially) spatially fixed at its end points and its center point, but rotatably connected to the substrate. This S-shape corresponds to the second eigenmode of a freely oscillating cantilever spring. In the following, a cantilever spring consisting of several segments, which is divided, for example, by the torsion spring elements, will also be understood as a single cantilever spring. The reference to the second eigenmode above therefore refers to the entire part of the cantilever spring lying between the outer connection points.

[0022] The midpoints between the connections to the substrate form points of greatest deflection, which also have opposite amplitudes and move purely linearly and parallel. The movement of the cantilever spring can, in particular, correspond to a standing wave with fixed endpoints and a fixed center.

[0023] Since the oscillation systems are connected to the cantilever spring at the points of maximum deflection, the movements of the oscillation systems are also forced onto linear and parallel paths. The use of torsion springs thus improves the guided deflection of the oscillation systems and thus the reliability and accuracy of the angular rate sensor.

[0024] When the first and second vibration systems deflect in opposite directions, forces acting on the cantilever spring can generate a first torque M1 on the first torsion spring element, a second torque M2 on the second torsion spring element, and a third torque M3 on the third torsion spring element. The first torsion spring element can have a first spring constant K1 with respect to rotations, the second torsion spring element can have a second spring constant K2 with respect to rotations, and the third torsion spring element can have a third spring constant K3 with respect to rotations, whereby the relationship applies: K1:K2:K3 = M1:M2:M3.

[0025] The first vibration system connected between the first and second torsion spring elements exerts a force on the cantilever spring due to the vibration excited therein. This force is transmitted via the cantilever spring to the first torsion spring element and the second torsion spring element, generating a torque there in each case. In the opposite direction, the second vibration system exerts an opposing force on the second and third torsion spring elements, also generating torques there. These torques must be absorbed by the torsion spring elements, which leads to deformations of the torsion spring elements, in particular to twisting. In order to achieve particularly symmetrical bending of the cantilever spring, the spring constants should be adapted to rotations, i.e.the torsional stiffness of the torsion spring elements with respect to these deformations is in the same ratio to each other as the torques exerted by the vibration systems as a whole on the torsion spring elements.

[0026] In particular, the first and third torsion spring elements can have the same spring constant with respect to rotations K1 = K3 and the second torsion spring element can have a spring constant with respect to rotations K2 that is twice as large as the spring constant of the outer torsion spring elements, i.e. K1:K2:K3 = 1:2:1. This is particularly suitable for a symmetrical structure in which the oscillation systems are connected to the bending beam spring exactly in the middle between two torsion spring elements and the two sections of the bending beam spring between the middle torsion spring element and the two outer torsion spring elements are the same. In this case, the torques acting on the middle, i.e. second, torsion spring element are doubled compared to the torques acting on the outside. This can be counteracted by the particularly simple ratio K1:K2:K3 = 1:2:1, which in this case results in an exactly synchronous movement in push-pull for the oscillation systems.

[0027] The torsion spring elements can be moved both twisted relative to the substrate and linearly relative to the substrate. This can be useful if the cantilever spring is not stretchable enough to provide the necessary length change due to the deformation and the fixed connection to the substrate. In this case, the torsion spring element can generate deformation along the second direction in addition to rotation, causing the sections of the cantilever spring located between the torsion spring elements to "lengthen." The cantilever spring then consists not of a single continuous cantilever, but of two (or more) sections connected at their ends to the torsion spring elements. Both sections together are referred to here as a cantilever spring.

[0028] The linear deformability of the torsion spring elements leads to a linear displacement of the connection point between the cantilever spring and the torsion spring element relative to the substrate. This also allows the use of cantilevers that deform without changing length, since the required change in length is replaced by the displacement of the connection point. This allows the micro-electro-mechanical component to be manufactured from a material that is advantageous for its functionality without having to consider its elastic properties. This also improves the reliability of the micro-electro-mechanical component.

[0029] The torsion spring elements can have a size of less than 1000 µm, 500 µm, 150 µm, 100 µm, 50 µm, 30 µm, 10 µm, or 5 µm. The smaller the torsion spring elements, the closer the first eigenmode of the coupling device approximates a sinusoidal oscillation with precisely parallel and counter-moving points of maximum deflection. Smaller torsion spring elements therefore improve the deflection of the oscillation systems and thus the reliability of the micro-electro-mechanical component.

[0030] The connections between the first and second vibration systems and the coupling device along the second direction can have a width that is less than 250 µm, 200 µm, 150 µm, 100 µm, 50 µm, 30 µm, 10 µm, 5 µm, or 1 µm. The deformability of the cantilever spring is varied in the region of the connections to the vibration systems. The narrower this region, i.e., the more uniform the deformability of the cantilever spring, the more purer a sinusoidal oscillation can be formed, which improves the micro-electromechanical component for the reasons stated above.

[0031] The micro-electro-mechanical component can have a further coupling device that is constructed identically to the previously described coupling device. Here, the first and second oscillation systems are arranged along the first direction between the two coupling devices, and the two coupling devices are connected to the first and second oscillation systems in the same way. The guidance or coupling of the oscillation systems thus takes place from two sides opposite each other along the oscillation direction. This improves the guidance and thus the linearity of the oscillation.

[0032] The first and second oscillation systems can each have two masses that can be excited to oscillate in opposite directions along the first direction. Rotation during excited oscillation along the first direction triggers a Coriolis force acting on the masses along the second direction, the magnitude of which can be measured to determine the rotation rate. The first and second oscillation systems have an identical and symmetrical structure, due to which the micro-electro-mechanical component as a whole is force- and torque-free, at least on average over time, during excited oscillations of the masses.

[0033] The two oscillation systems are thus designed as dual-mass yaw rate sensors with two masses that can be excited to oscillate in counter-phase within a single oscillation system. Furthermore, the masses of the two dual-mass sensors also oscillate in counter-phase with respect to each other. Outward-acting forces are then always compensated by correspondingly large inward-acting forces. Rotation of the quad-mass yaw rate sensor generated by this arrangement results in Coriolis forces on all masses. These forces also compensate each other precisely. Averaged over time, the yaw rate sensor is therefore force- and torque-free. This is supported by the coupling devices described above, as they ensure a coupled, linear, counter-phase movement.

[0034] The present invention will be described in more detail below with reference to the accompanying figures. This description is purely exemplary. The invention is defined only by the subject matter of the claims. It shows: Fig. 1A und 1B schematic representations of a coupling device; Fig. 2 a schematic representation of a coupling device; Fig. 3 a schematic representation of a torsion spring element; Fig. 4 a schematic representation of a yaw rate sensor; and Fig. 5A und 5B schematic representations of another yaw rate sensor.

[0035] The Fig. 1A und 1B schematically show a micro-electromechanical component, such as an inertial sensor or a yaw rate sensor 100, which are designed as micro-electromechanical systems (MEMS). For the sake of simplicity, reference is always made below to a yaw rate sensor 100, but this is not intended to be limiting.

[0036] The yaw rate sensor 100 is capable of detecting rotations about an axis perpendicular to the image plane. For this purpose, the yaw rate sensor 100 comprises a first oscillation system 110 and a second oscillation system 120, which are mounted above a substrate 200 of the yaw rate sensor 100.

[0037] These two vibration systems 110, 120 are in the Fig. 1A und 1B shown in a highly schematic manner. Both vibration systems 110, 120 have components that are movable in a first direction with respect to the substrate, as shown in the Fig. 1A und 1B represented by arrows A and B. The first direction corresponds to the Fig. 1A und 1B the x-direction or the x-axis. The movement of the components of the oscillation systems 110, 120 along the x-direction makes it possible to determine angular rates in a known manner via the effects of the Coriolis force, either for each oscillation system 110, 120 separately or by combining both oscillation systems 110, 120. Since this is well known, the internal structure of the oscillation systems 110, 120 does not need to be explained in detail here. In principle, it can correspond to any structure suitable for angular rate measurement. Oscillation systems with a similar motion pattern can also be incorporated into other micro-electro-mechanical components that serve a different purpose.

[0038] The decisive factor is that the first oscillation system 110 and the second oscillation system 120 must be deflected in opposite directions along the first x-direction for optimal operation of the micro-electro-mechanical component or the yaw rate sensor 100. "Opposite" here includes both opposite movements purely in the x-direction, as well as opposite movements that are tilted against the x-direction and relative to each other. Preferably, however, both oscillation systems run linearly and parallel along the x-direction. This means that while the first oscillation system 110 (or parts thereof relevant for the yaw rate measurement) is in the Fig. 1A If the first oscillation system 120 moves to the right, the second oscillation system 120 (or parts thereof relevant for the rotation rate measurement) moves to the left, and vice versa. Although the respective movements or oscillations of the oscillation systems 110, 120 can be excited by mechanisms arranged in the oscillation systems 110, 120, such as pairs of driver electrodes, a mechanical coupling between the oscillating bodies is advantageous in order to reliably guide the opposing movement, if possible in push-pull.

[0039] As in the Fig. 1A As can be seen, the first and second oscillation systems 110, 120 are arranged next to one another perpendicular to the first direction, i.e. along the y-direction, i.e. they are parallel to one another and offset from one another in the y-direction. Coupling mechanisms known from the prior art which are suitable for coupling along the direction of movement of oscillations cannot therefore be used for yaw rate sensors 100 of interest here. Rather, the coupling must be effected via a coupling device 130 which extends along the y-direction, i.e. along a second direction perpendicular to the first direction. The coupling device 130 does not have to follow the second direction in a purely linear or rectilinear manner, but can also have segments which are inclined with respect to the second direction, i.e. run obliquely or even perpendicular to the second direction.What is crucial is that the coupling device 130 is capable of coupling vibration systems 110, 120 that are arranged offset in the y-direction.

[0040] To enable this coupling, the movement taking place within the vibration systems 110, 120 must be mechanically detectable from outside the vibration systems 110, 120, otherwise a connection to the coupling device 130 is not possible. This is described in the Fig. 1A und 1B by the displacement of the entire block representing the oscillation system 110, 120. However, this only serves to simplify the description and should not be understood as limiting. Whenever the movement or oscillation of an oscillation system 110, 120 or its connection to the coupling device 130 is mentioned below, this should be understood as a statement about the components moving within the oscillation system 110, 120, which are to be brought into counter-phase by the coupling device 130.

[0041] As in the Fig. 1A und 1B As shown, the coupling device 130 has a bending beam spring 135 connected to the vibration systems 110, 120. The bending beam spring 135 is capable of being deflected in the x-direction. It has a stiffness in the x-direction that can be lower than the stiffnesses with respect to movements in other directions. The bending beam spring 135 can be composed of several segments, e.g., several bending beams, and can in principle also have subsections that can be deformed perpendicular to the x-direction, for example, to bring about a change in the length of the bending beam spring 135.

[0042] The cantilever spring 135 can be connected to the substrate 200 at at least three connection points 140, i.e., at the connection points 140, the mobility of the cantilever spring 135 in the x- and y-directions is severely restricted. Ideally, the cantilever spring 135 cannot move in the x- and y-directions at the connection points 140. However, the cantilever spring 135 can ideally still be rotated above the connection points 140. The middle connection point 140, shown hatched, can, in principle, also be omitted.

[0043] Between each pair of the three connection points 140 are connections 112, 122 to the two vibration systems 110, 120. The connections can have any shape that is advantageous for connecting the cantilever spring 135 and the vibration systems 110, 120. For example, the cantilever spring 135 can be more solid or flexible in the area of ​​the connections 112, 122 than in other areas, or can be formed with multiple, possibly parallel, segments. The cantilever spring 135 can also be straight or curved in the area of ​​the connections 112, 122 if this allows for an improved connection to the vibration systems 110, 120.

[0044] A deflection of the oscillation systems 110, 120 leads, as in the Fig. 1B shown, leads to a bulging of the cantilever spring 135 in the direction of the deflection. Due to the rotatable connection of the cantilever spring 135 to the substrate, a deflection to the right in the upper half of the cantilever spring 135 leads to a deflection to the left in the lower half. This is because, due to the rotatable mounting at the central connection point 140, no force acts on the cantilever spring 135 in this area that would lead to a deviation from a first-order rectilinear course of the cantilever spring 135 in this area. However, the cantilever spring 135 is fixed at the lower connection point 140.

[0045] If the first oscillation system 110 now pulls the bending beam spring 135 to the right in its upper half, the bending beam spring 135 bends in such a way that it runs essentially straight from the top right to the bottom left in its middle region, before then bending back to the right in the direction of the lower connection point 140. The bending beam spring 135 thus bulges to the left in the lower region and forces the second oscillation system 120 to follow this movement, as shown in the Fig. 1B shown. In this way, the coupling device guides the two oscillation systems 110, 120 in their counter-rotating motion, ideally always in counter-phase.

[0046] A symmetrical structure is advantageous here, as in the Fig. 1A und 1B shown, in which the outer connection points 140 are connected to the ends of the cantilever spring 135, and the middle connection point 140 is located exactly in the middle of the cantilever spring 135. The connections 112, 122 to the vibration systems 110, 120 are then located at one-quarter and three-quarters of the length of the cantilever spring 135, respectively, or exactly between the respective connection points 140.

[0047] The cantilever spring 135 then has a uniform thickness along its length and can therefore exhibit a uniform spring constant. Due to this symmetrical design, the oscillation systems 110, 120 always move with opposite amplitudes and phases, meaning the magnitude of the deflection is the same and the direction of the deflection is different.

[0048] This counter-rotating motion of the oscillation systems 110, 120 can also be achieved with a not entirely symmetrical structure, if a cantilever spring with a correspondingly adapted spring constant that is not constant over its length is used. Ultimately, the dimensioning, type, and segmentation of the cantilever spring 135, and thus the value of the spring constant along the second direction, determine the deformation of the cantilever spring 135 for a given arrangement of the connection points 140 and a given force distribution due to the deflection of the oscillation systems 110, 120. This makes it possible to enable counter-rotating motion of the oscillation systems 110, 120 for almost all possible arrangements of connection points 140 to the substrate 200 and of connections 112, 122 to the oscillation systems.

[0049] The deformation of the cantilever spring 135 ideally corresponds to a standing wave whose points of maximum deflection are located at the connections 112, 122 to the oscillation systems 110, 120 and move rectilinearly along the first direction.

[0050] In particular, the connection between substrate 200, cantilever spring 135, and oscillation systems 110, 120 can be configured such that the first eigenmode of the thus formed coupling device 130 corresponds to the second eigenmode of a freely oscillating cantilever spring 135. This means that upon excitation, the cantilever spring 135 does not form one oscillation antinode (first eigenmode of the free cantilever spring), but rather forms two oscillation antinodes. In other words, the segments of the cantilever spring 135 located between the connection points oscillate in the first eigenmode of the free cantilever spring, and the cantilever spring 135 composed of the segments thus oscillates in the second eigenmode.

[0051] According to the first solution according to the invention, in contrast to the above description of the Fig. 1A und 1B The hatched central connection point 140 has been omitted. In this case, too, an oscillation of the cantilever spring 135 can be generated, which couples the oscillation systems 110, 120 in push-pull mode. This can be achieved, for example, by appropriately positioning the connections 112, 122 between the oscillation systems 110, 120 and the cantilever spring 135, which promotes the formation of the oscillation mode in which each oscillation system 110, 120 is connected to the cantilever spring 135 in the region of an antinode. Additionally or alternatively, the oscillation systems 110, 120 can also oscillate in push-pull mode such that the oscillation frequency is the natural frequency of such an oscillation mode or is close to it. The connections are advantageously located at the maximum of the antinodes, i.e., at the points of maximum deflection of the cantilever spring 135.

[0052] As a further alternative, instead of two oscillation systems 110, 120, a plurality of oscillation systems can also be coupled by the bending beam spring 135. In this case, the arrangement or operating frequency of, for example, N oscillation systems must be such that the bending beam spring forms N oscillation antinodes in the region of the respective connections to the oscillation systems. According to the first solution according to the invention, this is supported by a uniform distribution of the N oscillation systems along the length L of the bending beam spring between two connection points 140, in which the nth oscillation system is located at the position (2n-1)·L / 2N of the bending beam spring 135. Neighboring oscillation systems then oscillate in counter-phase. With two oscillation systems 110, 120, this corresponds to the positioning described above at one-quarter or three-quarters of the length of the bending beam spring between two connection points 140. It is also possible to leave some of the N positions free.This allows coupling to be achieved in which part of neighboring oscillation systems runs in sync.

[0053] A large number of vibration systems can be coupled in a simple manner by means of an essentially freely oscillating cantilever spring 135. On the other hand, the above-mentioned Fig. 1A und 1B The variant described with an intermediate connection of the bending beam spring 135 and the substrate 200 has the advantage that the counter-coupling vibration mode is formed more easily.

[0054] According to the second solution according to the invention, in three connections of the bending beam spring 135 to the substrate 200, these are designed as torsion spring elements 132, 134, 136, as shown in the Fig. 2 are shown schematically. This allows for a simple relative rotation between the cantilever spring 135 and the substrate 200, while simultaneously maintaining a firm connection to the substrate.

[0055] The Fig. 2 shows schematically the formation of torques and forces on the torsion spring elements 132, 134, 136 of the coupling device 130. A first torsion spring element 132 is connected to one end of the bending beam spring 135, a second torsion spring element 134 to the middle of the bending beam spring 135 and a third torsion spring element 136 to the other end of the bending beam spring 135. The torsion spring elements 132, 134, 136 are thus located at the connection points 140, which are in the Fig. 1A und 1B are shown. The structure of the bending beam spring 135 is assumed to be symmetrical to the middle, second torsion spring element 134.

[0056] The connection 112 to the first vibration system 110 is located between the first and second torsion spring elements 132, 134, the connection 122 to the second vibration system 120 is located between the second and third torsion spring elements 134, 136. If the first vibration system 110 moves in the positive x-direction, a corresponding force acts on the bending beam spring 135. This is shown in the Fig. 2 shown by the arrow C. This force is transmitted via the bending beam spring 135 to the first and second torsion spring elements 132, 134 and leads to a torque, which causes a twisting of the torsion spring elements 132, 134, as shown in the Fig. 2 represented by rotating arrows.

[0057] In the same way, a force in the negative x-direction acts from the second oscillation system 120 on the bending beam spring 135, in which Fig. 2 shown by the arrow D. This force is also transmitted to the adjacent torsion spring elements 134, 136 and causes a torque there, which causes the torsion spring elements 134, 136 to rotate.

[0058] To ensure a counter-balanced deflection of the two oscillation systems 110, 120, all torsion spring elements 132, 134, 136 must rotate by the same amount, otherwise the connections 112, 122 to the oscillation systems 110, 120 would no longer execute equal and linear movements. This can be ensured by adjusting the spring constants of the torsion spring elements 132, 134, 136 with respect to rotations according to the torques acting on the torsion spring elements 132, 134, 136 during the deflection of the oscillation systems 110, 120. The first torsion spring element 132 has a spring constant K1 with respect to rotations, the second torsion spring element 134 has a spring constant K2, and the third torsion spring element 136 has a spring constant K3.If the torque M1 acts on the first torsion spring element 132, the torque M2 acts on the second torsion spring element 134, and the torque M3 acts on the third torsion spring element 136, which are in the ratio M1:M2:M3, then preferably K1:K2:K3 = M1:M2:M3. The ratios of the torques are therefore equal to the ratios of the spring constants to rotations.

[0059] With a symmetrical structure, as in the Fig. 2 As shown, the torque M2 on the middle torsion spring element 134 resulting from the acting forces C and D is twice as large as the torques M1, M3 on the outer torsion spring elements 132, 136. In the case of a symmetrical structure of the connections between substrate 200, cantilever spring 135 and vibration systems 110, 120, a ratio of the spring constants of K1:K2:K3 = 1:2:1 is therefore suitable in order to force the vibration systems 110, 120 to move as linearly and parallel as possible.

[0060] Alternatively, even in the case of an asymmetrical structure, a linear deflection of the vibration systems 110, 120 can be ensured by selecting appropriate spring constants.

[0061] As explained above, designs without the central torsion spring element 134 are also conceivable. This has the advantage that, for the most uniform deflection possible, only the two outer torsion spring elements 132, 136 need to be coordinated with each other. For example, it may be sufficient to make the spring constants with respect to rotations identical by designing the outer torsion spring elements 132, 136 identically. This further simplifies the structure of the coupling device 130.

[0062] In the Fig. 1A bis Fig. 2 The connection of the cantilever spring 135 to the substrate is shown as a point-like connection. This is the case when the cantilever spring 135 is designed continuously and is supported at the connection points 140, for example, by rotatable posts. Due to the stiffness of the cantilever spring 135 and the material typical of MEMS angular rate sensors, the cantilever spring 135 cannot be deflected very far without being damaged.

[0063] As an alternative to such a point-like mounting of a continuous cantilever spring, the cantilever spring 135 can also be interrupted at the connection points 140, in particular at the central connection point 140, in order to use a torsion spring element 134 that can perform not only rotational movements but also linear movements relative to the substrate 200. This allows the cantilever spring 135 to be deflected further, since a compression of the cantilever spring 135 due to the deflection can be compensated by a corresponding extension of the torsion spring element 134.

[0064] The Fig. 3 is a schematic representation of such a torsion spring element 134. In the Fig. 3 The capability for rotational movement is represented by the spiral spring 131 connected to the substrate 200 at connection point 140. The possibility for linear movement is represented by the two linear springs 133, to which the cantilever spring 135 is connected. These are only simplified representations for explaining the function of the torsion spring element 134. The concrete implementation of the corresponding components can be carried out in many ways that are familiar to a person skilled in the art. In particular, pure torsion springs and pure linear springs are known in the field of MEMS. The combination of these two principles in a torsion spring element 134 is advantageous here.

[0065] The Fig. 3 shows the torsion spring element in the non-deflected state, as in the Fig. 1A The spiral spring 131 is not twisted, the linear springs 131 are neither contracted nor stretched. If a deflection occurs, as shown in the Fig. 2 As shown, the coil spring 131 rotates around the connection point 140 such that the left linear spring 133 moves upward and the right linear spring 133 moves downward. At the same time, the linear springs 133 are stretched by the bulging of the bending beam spring 135 in the area of ​​the connections 112, 122 to the vibration systems 110, 120, since the compression of the bending beam spring creates a tensile force on the torsion spring element 134.

[0066] The linear springs 133—or the possibility of linear movements through the torsion spring element 134—make the length of the multi-segmented bending beam spring 135 variable. This allows for larger deflections of, for example, more than 2 µm, 5 µm, 10 µm, 15 µm, or 20 µm, which increases the sensitivity of the yaw rate sensor 100.

[0067] Such linear springs for changing the length of the bending beam spring 135 can also be part of the bending beam spring 135. This then has sections that can deform perpendicular to the actual main deflection direction, i.e., perpendicular to the x-direction, such as forks of the bending beam spring 135 and / or parallel sections of the bending beam spring 135.

[0068] By dividing the cantilever spring 135 into several segments separated by torsion spring elements 134, the oscillation shape of the cantilever spring 135 can deviate from that of a standing wave. To prevent this, it is advantageous to design the torsion spring elements 134 as small as possible, e.g., with a size of less than 1000 µm, 500 µm, 150 µm, 100 µm, 50 µm, 30 µm, 10 µm, or 5 µm. The size of the torsion spring elements 134 can be defined as the diameter of a circle into which the torsion spring element 134 can be fitted or the distance between the segments of the cantilever spring 135 connected by the torsion spring element 134.

[0069] Just like the torsion spring elements 132, 134, 136, the connections 112, 122 to the shrinkage systems 110, 120 can also hinder the oscillation of the cantilever spring 135 in the form of a standing wave. Therefore, it is advantageous if the width of the connections 112, 122 in the y-direction is less than 250 µm, 200 µm, 150 µm, 100 µm, 50 µm, 30 µm, 10 µm, 5 µm, or 1 µm to ensure the most rectilinear movement of the cantilever spring 135 in the area of ​​the connections 112, 122.

[0070] In addition to the Fig. 1A und 1B In addition to the coupling device 130 shown, the rotation rate sensor 100 can have a further coupling device 130, which is constructed completely analogously to the previously described coupling device 130. This is shown schematically in the Fig. 4 shown.

[0071] The first and second oscillation systems 110, 120 are located in the x-direction between the two coupling devices 130, both of which extend in the y-direction. The oscillation systems 110, 120 are thus guided at both ends by the coupling devices 130, which further improves the linearity and parallelism of the movement.

[0072] In the Fig. 1A, 1B and 4 The movement of the oscillation systems 110, 120 is shown such that the first oscillation system 110 and the second oscillation system 120 always have the same outer circumference, which shifts with respect to the substrate 200. As already mentioned above, this is only a simplified representation that does not necessarily correspond to the conditions in an actual implementation. The same deflections for both coupling devices 130 in the Fig. 4 is accordingly also to be understood as purely schematic. Sections of the coupling devices 130 located at the same height in the y-direction do not necessarily have to have exactly the same deflection if the geometry of the oscillation systems 110, 120 requires otherwise. What is crucial is that the coupling devices 130 force the oscillation systems 110, 120 to move in opposite directions in the x-direction.

[0073] The Fig. 5A und 5B show a configuration of the oscillation systems 110, 120 that can be used in quad-mass sensors. Here, the first oscillation system 110 has two masses 115 that oscillate against each other in counter-phase along the x-direction. Likewise, the second oscillation system has two masses 125 that oscillate against each other in counter-phase along the x-direction. The first oscillation system 110 and the second oscillation system 120 each form dual-mass sensors, the coupling and detailed structure of which are known to a person skilled in the art and need not be explained further here.

[0074] Advantageous when using dual mass sensors, as used in the Fig. 5A und 5B shown is that forces caused by the vibrations, such as spring forces, compensate each other within the dual-mass sensor, ie for every force there is an equally large but oppositely directed force.

[0075] However, it cannot be ruled out that torques may occur due to the acting forces that do not fully compensate each other. To solve this problem, the masses 115 of the first oscillation system 110 and the masses 125 of the second oscillation system 120 also oscillate in counter-phase. If the masses 115 of the first oscillation system 110 move inward, the masses 125 of the second oscillation system 120 move outward, and vice versa, as shown in the Fig. 5A marked by the arrows E.

[0076] The advantage of this arrangement can be Fig. 5B If the yaw rate sensor 100 is subjected to a rotation about an axis perpendicular to the image plane (indicated by the arrow F in the Fig. 5B symbolized), a Coriolis force acts on the masses 115, 125. As in the Fig. 5B Schematically shown, this is directed downwards for counterclockwise rotations for masses moving to the right and upwards for masses moving to the left. The resulting Coriolis force can be measured, for example, by detecting the deflection of the masses from the purely linear motion using capacitors or by using a control loop to determine the electrical voltage that must be applied to the capacitors to prevent a deviation from the linear motion in the x-direction. The precise method of determining the Coriolis force and the resulting derivation of the rotation rate are known per se and need not be discussed further here.

[0077] Since the respective masses 115, 125 of a vibration system 110, 120 are located to the left and right of the center of the vibration system 110, 120, the forces acting on the two masses generate torques in the same direction. A single vibration system or a single dual-mass sensor is therefore force-free, but not necessarily torque-free.

[0078] The vibration systems 110, 120 in the quad-mass arrangement of the Fig. 5A und 5B are constructed identically and oscillate in opposite phase. The torques induced by the Coriolis force in the two oscillation systems 110, 120 are therefore (when averaged over one oscillation period) exactly opposite, meaning they have the same magnitude but opposite directions. This makes quad-mass sensors force- and torque-free.

[0079] However, this is only achieved for a substantially parallel and rectilinear oscillation of the masses 115, 125 of the two oscillation systems 110, 120. For this reason, the use of coupling devices 130, as described above, is particularly advantageous for quad-mass sensors, as they are capable of forcing both oscillation systems 110, 120 onto the advantageous parallel and linear paths. In particular, the use of cantilever springs 135, which are connected to the torsion spring elements 132, 134, 136 described above in such a way that the cantilever spring 125 oscillates in the form of a standing wave upon excitation of the oscillations of the oscillation systems 110, 120, is advantageous because the oscillation systems 110, 120 can then be guided into the maxima of the standing wave, which moves exclusively along the x-direction. In this way, robust, reliable and high-precision angular rate sensors 100 can be provided.

Claims

1. A micro-electro-mechanical component, preferably an inertial sensor, more preferably a rotation rate sensor (100) for measuring a rotation of the rotation rate sensor (100), comprising: a coupling device (130) for coupling a plurality of vibration systems (110, 120), which are mounted above a substrate (200) in such a manner that said systems can vibrate along a first direction (x) and are offset with respect to one another in a second direction (y) perpendicular to the first direction (x), wherein the coupling device has a bending beam spring (135) which can bend in the first direction (x) and is connected to the vibration systems (110, 120), and connections (112, 122) of the bending beam spring (135) to the vibration systems (110, 120) are arranged between two connection points (140) of the bending beam spring (135) to the substrate (200) in such a manner that a deflection of the bending beam spring (135) which is caused by movements of the vibration systems (110, 120) results in a vibration of the bending beam spring (135) with vibration antinodes in the area of the connections (112, 122) of the bending beam spring (135) to the vibration systems (110, 120); and the plurality of vibration systems (110, 120), wherein the number of vibration systems (110, 120) is N, and wherein a length of the bending beam spring (135) between two connection points (140) to the substrate (200) is L, characterized in that there are no further connection points to the substrate (200) between said two connection points (140); and the vibration system n (n=1, ...,N) is connected to the bending beam spring (135) at (2n-1)·L / 2N.

2. The micro-electro-mechanical component, preferably an inertial sensor, more preferably a rotation rate sensor (100) for measuring a rotation of the rotation rate sensor (100), comprising: a coupling device (130) for coupling a plurality of vibration systems (110, 120), which are mounted above a substrate (200) in such a manner that said systems can vibrate along a first direction (x) and are offset with respect to one another in a second direction (y) perpendicular to the first direction (x), wherein the coupling device has a bending beam spring (135) which can bend in the first direction (x) and is connected to the vibration systems (110, 120), and connections (112, 122) of the bending beam spring (135) to the vibration systems (110, 120) are arranged between at least two connection points (140) of the bending beam spring (135) to the substrate (200) in such a manner that a deflection of the bending beam spring (135) which is caused by movements of the vibration systems (110, 120) results in a vibration of the bending beam spring (135) with vibration antinodes in the area of the connections (112, 122) of the bending beam spring (135) to the vibration systems (110, 120); and a first vibration system (110) and a second vibration system (120); wherein the coupling device (130) is connected to the substrate (200) at three connection points (140) and is connected to the first vibration system (110) between one pair of adjacent connection points (140) and is connected to the second vibration system (120) between the other pair of adjacent connection points (140), characterized in that the coupling device (130) further includes first, second and third torsion spring elements (132, 134, 136); the first torsion spring element (132) connects a first end of the bending beam spring (135), the second torsion spring element (134) connects the center of the bending beam spring (135), and the third torsion spring element (136) connects a second end of the bending beam spring (135) to the substrate (200); the first vibration system (110) is connected to the bending beam spring (135) midway between the first and second torsion spring elements (132, 134), and the second vibration system (120) is connected to the bending beam spring (135) midway between the second and third torsion spring elements (134, 136); and in the case of an opposite direction deflection of the first and second vibration systems (110, 120) along the first direction (x), the second mode of the bending beam spring (135) forms as the first mode of the coupling device (130), thereby forcing the first and second vibration systems (110, 120) to move in parallel.

3. The micro-electro-mechanical component according to claim 2, wherein, in the case of opposite direction vibrations of the first vibration system (110) and the second vibration system (120) along the first direction (x), the coupling device (130) forces them to move in push-pull mode, preferably, in parallel.

4. The micro-electro-mechanical component according to any one of claims 2 to 3, wherein the coupling device (130) forces the first and second vibration systems (110, 120) to vibrate with amplitudes and phases equal in magnitude, but in opposite directions.

5. The micro-electro-mechanical component according to any one of claims 2 to 4, wherein the movement of the bending beam spring (135) corresponds to a stationary wave with fixed end points and a fixed center point.

6. The micro-electro-mechanical component according to any one of claims 2 to 5, wherein, in the case of an opposite direction deflection of the first and second vibration systems (110, 120), a first torque M1 abuts the first torsion spring element (132), a second torque M2 abuts the second torsion spring element (134), and a third torque M3 abuts the third torsion spring element (136); the first torsion spring element (132) includes a first spring constant K1 with respect to rotations, the second torsion spring element (134) includes a second spring constant K2 with respect to rotations, and the third torsion spring element (136) includes a third spring constant K3 with respect to rotations; and the following relationship applies: M1:M2:M3 = F1:F2:F3.

7. The micro-electro-mechanical component according to any one of claims 2 to 6, wherein the first and third torsion spring elements (132, 136) have the same spring constant K1 = K3 with respect to rotations; and the second torsion spring element (134) has a spring constant K2 with respect to rotations which is twice as large as the spring constant of the first and third torsion spring elements (132, 136), i.e., K1:K2:K3 = 1:2:1 applies.

8. The micro-electro-mechanical component according to any one of claims 2 to 7, wherein the torsion spring elements (132, 134, 136) can be twisted with respect to the substrate (200), as well as moved linearly with respect to the substrate (200).

9. The micro-electro-mechanical component according to any one of claims 2 to 8, wherein the torsion spring elements (132, 134, 136) have a size of less than 1000µm, 500µm, 150µm, 100µm, 50µm, 30µm, 10µm or 5µm.

10. The micro-electro-mechanical component according to any one of claims 2 to 9, wherein connections (112, 122) between the first and second vibration systems (110, 120) and the coupling device (130) along the second direction (y) have a width that is less than 250µm, 200µm, 150µm, 100µm, 50µm, 30µm, 10µm, 5µm or 1µm.

11. The micro-electro-mechanical component according to any one of claims 2 to 10, further comprising: an additional coupling device (130) which is identical in construction to the coupling device (130); wherein the first and second vibration systems (110, 120) are arranged between the two coupling devices (130) along the first direction (x), and the two coupling devices (130) are connected to the first and second vibration systems (110, 120) in the same manner.

12. The micro-electro-mechanical component according to any one of claims 2 to 11, wherein the first and second vibration systems (110, 120) each have two masses (115, 125) that can be initiated to vibrate in opposite directions along the first direction (x); a rotation with vibration initiated along the first direction (x) releases a Coriolis force acting on the masses (115, 125) along the second direction (y), the magnitude of which can be measured to infer the rate of rotation; and the first and second vibration systems (110, 120) have an identical and symmetrical structure, due to which the micro-electro-mechanical component as a whole is free of force and torque in the time average with the initiation of the vibrations of the masses (115, 125).