Microelectromechanical coupling device

Abstract

A microelectromechanical coupling device (100) for coupling microelectromechanical components has a flexible ring structure (110) that, at rest, forms a circle that can be deformed substantially parallel to the plane of the circle and that is suitable for coupling the microelectromechanical components, and a plurality of spring elements (120) that are suitable for connecting the ring structure (110) to a substrate (200). Each spring element (120) in this arrangement has at least one tangential spring (122) that can be deflected substantially tangentially with respect to the ring structure (110), and at least one radial spring (124) that can be deflected substantially in the radial direction of the ring structure (110). The tangential spring (122) and the radial spring (124) of each spring element (120) are stand-alone components and the ratio of spring stiffnesses of the tangential spring (122) and the radial spring (124) of each spring element (120) is configured in such a way that a vibration that deforms the ring structure (110) is more advantageous in terms of energy than a vibration that displaces the ring structure (110) in translation and / or in rotation with respect to the substrate (200) and / or in such a way that the natural frequency of the translational and / or rotational vibration and the nearest natural frequency of a deforming vibration are at an interval that is greater than 5% of the natural frequency of this deforming vibration.

Description

[0001] Microelectromechanical coupling device

[0002] The present invention relates to a microelectromechanical coupling device for coupling microelectromechanical components and to a ring gyroscope with such a coupling device.

[0003] In micromechanical measuring devices such as angular rate or acceleration sensors, different micromechanical components, such as vibration systems or masses, often have to be connected to each other in order to couple the respective movements.

[0004] Often, coupling via a freely suspended, unsupported ring would be desirable, as this reacts to a radial force with a deflection that has the same amplitude regardless of the circumferential location where the radial force is applied. It can also be advantageous to use a freely suspended ring as a yaw rate sensor, in which a detection oscillation is superimposed on an excitation oscillation during rotation due to the Coriolis force.

[0005] The problem here, however, is that without any connection to a substrate of the measuring device, translational modes, rotational modes (in which the ring rotates as a whole), or other parasitic modes form the first eigenmodes. These are undesirable. Furthermore, the production of an unsupported ring for coupling microelectromechanical components is associated with considerable manufacturing complexity.

[0006] One known example is the use of systems with multiple rings connected by short, stiff connections (so-called spokes). The spokes themselves are very space-saving, but this space saving is partially compensated for by the need to have multiple rings available to ensure appropriate bearings. In addition, due to their stiffness, the spokes do not have any resonances in the range of a few kHz. Homogeneous behavior in the circumferential direction is also difficult to achieve with this design. Alternatively, extremely long and therefore space-consuming, but also very soft springs are used. Although these can achieve low resonance frequencies, the deviations from the ideal ring are very large here too, since homogeneous behavior in the circumferential direction cannot be achieved.

[0007] The object of the present invention is therefore to provide a micromechanical coupling device or a ring gyroscope in which the excitation of translational modes can be suppressed and at the same time installation space can be saved compared to the known solutions.

[0008] This problem is solved by the subject matter of claim 1.

[0009] A microelectromechanical coupling device for coupling microelectromechanical components comprises a flexible ring structure that forms a circle at rest, can be deformed substantially parallel to the plane of the circle, and is suitable for coupling the microelectromechanical components; and a plurality of spring elements that are suitable for connecting the ring structure to a substrate. Each spring element comprises at least one tangential spring that can be deflected substantially tangentially to the ring structure and at least one radial spring that can be deflected substantially in the radial direction of the ring structure.The tangential spring and the radial spring of each spring element are independent components, and the ratio of spring stiffnesses of the tangential spring and the radial spring of each spring element is configured such that a vibration deforming the ring structure is energetically more favorable than a vibration translating and / or rotating the ring structure relative to the substrate, and / or such that the natural frequency of the translating and / or rotating vibration and the nearest natural frequency of a deforming vibration have a separation greater than 5% of the natural frequency of this deforming vibration. The separation between the natural frequencies is preferably in a range from 5% to 200%, more preferably from 5% to 100%, more preferably from 5% to 50% of the natural frequency of the deforming vibration.

[0010] The coupling device thus has a basic structure consisting of a ring mounted above a substrate. It has the shape of, for example, a closed web whose height perpendicular to the substrate is a multiple of its width parallel to the substrate. In the rest position, this ring forms a circle in the broadest sense, i.e., a closed curve parallel to the substrate. Deformation of the ring is then essentially only possible parallel to the substrate, meaning deflections perpendicular to the substrate are negligible for operation.

[0011] In order to suppress the translational and / or rotational mode or vibration, the ring structure is connected to the substrate via spring elements composed of tangential springs and radial springs, i.e. springs that can be deflected essentially tangentially to the ring structure or perpendicular to the ring structure. The spring stiffnesses of the tangential and radial springs can be adjusted independently of one another by appropriately dimensioning the springs during the design and manufacture of the coupling device. In this way, a ratio of the spring stiffnesses of the tangential and radial springs of each spring element can be set in which the translational mode or other disturbing modes such as rotational modes are energetically disadvantaged compared to at least one "true" vibration mode, i.e. vibration mode that deforms the ring structure, hereinafter also referred to as bending mode.This ensures that the ring structure deforms as desired when stimulated and does not simply move sideways.

[0012] Additionally or alternatively, by adjusting the ratio of the spring stiffnesses of the tangential and radial springs, it is possible to ensure that the natural frequency of the translational mode and / or the rotational mode differs sufficiently from the nearest natural frequency of the bending mode. This ensures that a force impulse acting on the coupling device, for example, exciting the translational mode, does not couple into and disrupt the intended vibration mode. In this way, disturbances to the operating vibration of the ring structure can be prevented.

[0013] The possibility of achieving the above-mentioned effects by providing independently acting tangential and radial springs can be understood as follows.

[0014] In the first non-translational mode, the ring oscillates in the shape of an ellipse. Two oscillation antinodes, i.e., locations of maximum amplitude, form at any given time. This mode is therefore also called an n = 2 eigenmode. Other bending eigenmodes with multiple oscillation antinodes are referred to as n = 3, 4, 5,... eigenmodes.

[0015] Due to the elliptical shape of the n = 2 eigenmode, the deviation of the ring from the circular shape in cylindrical coordinates can be parameterized for each point as follows: <t> r ,i = cos(20) for the radial direction and <t>e,i = - sin(26) for the tangential direction. The angle 0 describes the circumferential angle.

[0016] The points on the ring therefore experience both a radial and a tangential deflection. The tangential deflection is at most half the radial deflection. Furthermore, the sum of the radial deflections of the points is greater than the sum of the tangential deflections. Thus, there is more radial deflection than tangential deflection.

[0017] There are points that only experience a radial or tangential deflection, and points that experience a superimposed deflection in the radial and tangential directions.

[0018] If spring elements are used to suspend a ring structure, which have independently deflectable radial and tangential springs, the deflections in the radial and tangential directions can be controlled by adjusting the ratio of the spring stiffness of the tangential springs to the radial springs of each spring element. The greater the spring stiffness in the tangential direction compared to the spring stiffness in the radial direction, the less the tangential spring will deflect compared to the radial spring for the same amount of force. Accordingly, the ring structure is less easily deformed in the tangential direction than in the radial direction if the spring stiffness of the tangential springs is high compared to the spring stiffness of the radial springs.

[0019] In contrast to the n=2 eigenmode, a ring does not deform during translational motion, but behaves approximately like a rigid body with a mass. If the ring structure, coupled to the substrate by means of spring elements, moves purely translationally over the substrate, only the spring elements are deformed, not the ring structure. The deflection of the spring elements differs from the deflection of the spring elements in the n=2 eigenmode. Here, the tangential deflection no longer applies, being a maximum of half the radial deflection. Furthermore, the sum of the tangential deflections of the points is greater than in the case of the n=2 eigenmode. The sum of the radial deflections remains approximately unchanged.

[0020] A ring behaves analogously in a rotational mode. Here, the ring rotates as a rigid body around its central axis, and only the springs are deflected. In this case, the springs are deflected approximately exclusively in the tangential direction.

[0021] Accordingly, the translational and rotational modes of the ring structure can be suppressed or shifted to higher frequencies by using independent radial and tangential springs in each of the spring elements. Their separately adjustable spring stiffnesses allow them to suppress tangential deflection of the ring structure by more than half the radial deflection. The n = 2 eigenmode can thus be energetically favored over the translational and / or rotational modes.

[0022] The same applies to the higher bending eigenmodes (n=3, 4, 5, ...). These modes can also be energetically favored over the translational / rotational modes by appropriately designing the radial and tangential springs of the spring elements. Accordingly, by adjusting the spring stiffnesses, the eigenfrequencies of the vibration / bending eigenmodes can also be separated from the eigenfrequency of the translational and / or rotational modes.

[0023] The spring elements can be designed such that the ratio of the spring stiffness of the tangential spring to the spring stiffness of the radial spring is in a range from 1 to 3. This ensures that the translational mode and / or rotational mode is not the energetically most favorable mode or that its natural frequency is sufficiently far from the (or at least one) natural frequencies of the bending modes.

[0024] The ring structure can be adapted to excite vibrations with an amplitude, preferably in the range between 0.1 pm and 10 pm, during which the spring stiffnesses of the tangential springs and the radial springs remain constant. This means that both the tangential and the radial springs remain in the linear range during the vibrations caused by the ring structure during operation of the coupling device, in which the deflection is directly proportional to the deflecting force, i.e., in which the spring stiffness is constant. This can be achieved in particular by the separate design of the tangential and radial springs, which can cushion the movements in their respective preferred directions.

[0025] The spring elements can have a radial extension of less than 25% of the radius of the ring structure at rest. This is also made possible by the separate design of the tangential and radial springs. In particular, the radial springs can be narrow in the radial direction of the ring structure, occupying, for example, only 10% or 5% of the radius of the ring structure. Since the tangential springs only need / should allow for a smaller deflection than the radial springs, they can also be designed compactly. This allows for a compact suspension of the ring structure and thus a compact design of the coupling device.

[0026] The spring elements can be connected to the ring structure from the outside. This allows the installation space inside the ring structure to be kept free, for example, for additional components with additional functionality. Due to the small space requirement of the spring elements, not much space is required outside the ring structure either. The coupling device can thus be compact yet equipped with increased functionality.

[0027] Each spring element can be designed such that less than half the space is available for deflections of the tangential spring in the tangential direction than for deflections of the radial spring in the radial direction. As described above, vibrations of the ring structure should be energetically favored where the tangential movement component of the ring structure is at most half as large as the radial movement component. Accordingly, the space required for the tangential movements can be reduced, and the space freed up can be used for other components. This makes the coupling device more compact, yet it can still be equipped with a variety of components.

[0028] Electrodes for exciting and / or reading vibrations of the ring structure can be arranged between the spring elements in the circumferential direction of the ring structure. This makes the ring structure particularly compact. Each of the electrodes can extend in the circumferential direction over an angle of between 10° and 45°, measured from the center of the ring structure, preferably over an angle of between 15° and 30°, and more preferably over an angle of 18°. As a result, the electrodes are in contact with large, contiguous sections of the ring structure. This reduces the voltage across the electrodes required for a force to be applied / read. This makes the operation of the coupling device more efficient.

[0029] The spring elements can be evenly distributed along the circumference of the ring structure. This facilitates the manufacturing of the coupling device.

[0030] Each spring element can connect the ring structure to the substrate via exactly one anchor structure. This reduces the damping mechanism of so-called "anchor losses." Anchor losses occur when forces are introduced into the substrate via multiple points, which can then only be balanced at the substrate level. "Anchor losses" describe the energy that is introduced into the substrate by forces and moments at the anchors and dissipates through the substrate into the environment and is thus lost. This can be counteracted by balancing forces and moments and transferring these forces and moments to the substrate at as few and as central points as possible. Accordingly, the use of only one anchor structure reduces the occurrence of such anchor losses.

[0031] In each spring element, the radial spring can comprise a double-folded cantilever spring extending in the tangential direction and connected in the radial direction to the substrate and the tangential spring. The tangential spring can be a cantilever spring folded more than twice or comprise at least two double-folded cantilever springs extending in the radial direction and connected in the radial direction to the radial spring and the ring structure. This allows spring elements corresponding to the above to be manufactured in a simple manner.

[0032] A ring gyroscope can have a micromechanical coupling device as described above. The ring structure can be suitable for executing an excitation oscillation, which, upon rotation of the ring structure, is superimposed with a detection oscillation generated by the Coriolis force. The spring elements represent the microelectromechanical components. In this way, a ring gyroscope can be realized in which the unwanted translational mode or its natural frequency can be sufficiently separated from the desired operating modes or their frequencies.

[0033] The so-called "angular gain" of the second natural oscillation of the ring structure, which is formed from the ratio of Coriolis mass to twice the modal mass, can lie in a range between 0.3 and 0.4, preferably in a range between 0.35 and 0.4, and more preferably in a range between 0.38 and 0.4, with the endpoints being part of the specified ranges. The modal mass describes the proportional mass of the associated natural oscillation, i.e., an effective mass of the corresponding natural oscillation. It results from the eigenvector of the corresponding mode and the mass distribution. The Coriolis mass is composed of all mass points that move in the direction of the exciting oscillation during an excited oscillation and in the direction of the detection oscillation during detection. The so-called "angular gain" can be determined from the ratio of Coriolis mass to modal mass.The theoretical maximum angular gain is 1 (Foucault pendulum). A large angular gain is advantageous and can be understood as the amplification factor of the angular rate signal. Theoretically, the angular gain of a ring gyroscope in the n = 2 eigenmode is 0.4. With the coupling device described above, operated as a ring gyroscope, an angular gain can be achieved that is extremely close to this theoretical value.

[0034] The invention is further described below with reference to the figures. The figures and their descriptions are purely exemplary. The present invention is defined solely by the subject matter of the claims. It shows:

[0035] Figs. 1A and 1B show a schematic representation of a microelectromechanical coupling device;

[0036] Fig. 2 is a schematic representation of a spring element formed from a combination of a tangential spring and a radial spring; Figs. 3A and 3B are schematic representations of the deflections of the radial spring and the tangential spring of Fig. 2;

[0037] Fig. 4 is a schematic representation of another spring element;

[0038] Fig. 5 is a schematic representation of another spring element;

[0039] Fig. 6 is a schematic representation of another spring element;

[0040] Fig. 7 is a schematic representation of another spring element;

[0041] Fig. 8 is a schematic representation of another spring element;

[0042] Fig. 9 is a schematic representation of a ring gyroscope constructed from a microelectromechanical coupling device;

[0043] Fig. 10 is a schematic representation of another ring gyroscope; and

[0044] Fig. 11 is a schematic representation of the arrangement of electrodes and spring elements in a coupling device.

[0045] Figs. 1A and 1B show a schematic representation of a microelectromechanical coupling device 100 suitable for coupling microelectromechanical components, such as those used in microelectromechanical measuring devices, such as yaw rate and / or acceleration sensors. The microelectromechanical coupling device 100 can also form the basic structure of an annular yaw rate sensor. Fig. 1B is a section through Fig. 1A along line II.

[0046] The coupling device 100 has a flexible ring structure 110 and a plurality of spring elements 120. As shown in Fig. 1A, the ring structure forms a circle at rest and can be deformed essentially parallel to the plane of the circle. As can be seen from Fig. 1B, the ring structure 110 has a substantially rectangular cross-section perpendicular to the circular plane or perpendicular to a substrate 200 above which the ring structure 110 is mounted, with long sides perpendicular to the substrate 200 that are many times longer than the short sides parallel to the substrate 200. The ring structure 110 can therefore be viewed, for example, as a self-contained cantilever spring that can deform parallel to the substrate 200, wherein deformations perpendicular to the substrate 200 are negligible (in a first approximation). The shape of the ring structure 110 shown is purely exemplary.The ring structure 110 can have any shape that favors deformation essentially only parallel to the substrate plane. The ring structure 110 can also have a degenerate circular shape in the rest position, e.g., as an ellipse or a polygon with rounded corners. Such degenerate circular shapes are therefore also intended to be covered by the reference to the circular ring structure 110.

[0047] Coupling points 112 are indicated on the ring structure 110, at which the microelectromechanical components to be coupled engage or at which these components are connected to the ring structure 110. Through the coupling, movements between the microelectromechanical components can be transmitted or coordinated. In particular, the coupling device 100 can mediate a force- and torque-free push-pull oscillation between the components. The microelectromechanical components can be, for example, sensor masses or oscillation systems. In principle, however, the type, structure, and size of the components 200 to be coupled are arbitrary. Likewise, the number of components 200 can be greater than two.

[0048] The coupling can also be achieved via the spring elements 120. In this case, the coupling points 112 are omitted. In particular, if the coupling device 100 is part of a ring-shaped microelectromechanical rotation rate sensor, such as a ring gyroscope, the spring elements 120 can represent the microelectromechanical components. The ring structure is suitable for executing an excitation oscillation, onto which a detection oscillation generated by the Coriolis force is superimposed upon rotation of the ring structure 110.

[0049] The ring structure 110 is connected to the substrate 200 via a plurality of spring elements 120. The spring elements 120 engage at various points of the ring structure 110 and hold it above the substrate 200. As shown in Figs. 1A and 1B, the spring elements 120 can be connected to anchor structures 125 and thus connect the ring structure 110 directly to the substrate 200. The anchor structures 125 can have any

[0050] shape as long as they allow a fixed connection to the substrate 200.

[0051] As schematically shown in the enlargement of Fig. 1A, each spring element 120 has at least one tangential spring 122, which can be deflected substantially tangentially to the ring structure 110, and at least one radial spring 124, which can be deflected substantially in the radial direction of the ring structure 110.

[0052] The tangential spring 122 and the radial spring 124 are represented completely schematically in Fig. 1A by spiral spring symbols. These springs can have any desired shape, as long as the tangential spring 122 and the radial spring 124 of each spring element 120 are independent components and the ratio of spring stiffnesses of the tangential spring 122 and the radial spring 124 of each spring element 120 is configured such that a vibration deforming the ring structure 110 is energetically more favorable than a vibration translationally displacing the ring structure 110 relative to the substrate 200 and / or that the natural frequency of the translational vibration and the nearest natural frequency of a deforming vibration have a separation greater than 5% of the natural frequency of this deforming vibration.Preferably, the distance between the natural frequencies is in a range from 5% to 200%, more preferably from 5% to 100%, more preferably from 5% to 50% of the natural frequency of the deforming vibration.

[0053] The spring elements 120 thus consist of essentially independently deformable springs that divide the total movement / deformation of the spring elements 120 into a radial component and a tangential component, with the radial component being generated by the deformation of the radial spring 124 and the tangential component by a deformation of the tangential spring 122. The tangential spring 122 and the radial spring 124 are each separate assemblies whose dimensions and properties can be adjusted separately during the manufacturing process of the coupling device 100. In particular, the masses and thicknesses of the tangential springs 122 and the radial springs 124 can be designed differently, e.g., in an etching process, in order to achieve different spring stiffnesses.In this way, the ratios of the spring stiffnesses of the tangential springs 122 to the radial springs 124 can be adjusted such that a translational or rotational oscillation of the ring structure 110, i.e., an oscillation without deformation of the ring structure 110, becomes energetically less favorable than an oscillation that deforms the ring structure 110. Preferably, the second natural oscillation of the freely suspended ring structure 110, i.e., the n = 2 natural mode, in which two oscillation antinodes form, should become energetically more favorable than the translational or translational mode and / or rotational mode due to the connection to the spring elements 120. The ratio of the spring stiffnesses in the individual spring elements 120 can also be adjusted such that the natural modes of the freely suspended ring structure 110 are rearranged, i.e., that, for example,The n = 3 eigenmode of the freely suspended ring structure 110 becomes energetically more favorable than the n = 2 eigenmode due to the coupling with the spring elements 120. For this purpose, the spring stiffness ratios in the individual spring elements 120 can also be configured differently.

[0054] Instead of achieving a rearrangement of the excitation energies of the individual eigenmodes of the freely suspended ring structure 110 (or in addition to this), the ratio of the spring stiffnesses of the tangential spring 122 and the radial spring 124 can also be adjusted such that the eigenfrequencies of the eigenmodes are sufficiently far apart. In particular, the eigenfrequency of the translational mode and / or rotational mode should be sufficiently far apart from the initially occurring eigenfrequency of a bending mode deforming the ring structure 110 to ensure that force impulses exciting the translational mode do not couple into this bending mode and disrupt it. For this purpose, the eigenfrequencies can, for example, be separated by more than 5% of the eigenfrequency of the bending mode. The separation between the eigenfrequencies is preferably in a range from 5% to 200%, more preferably from 5% to 100%, more preferably from 5% to 50% of the eigenfrequency of the deforming oscillation.

[0055] The spring elements 120 can in particular be designed such that the ratio of the spring stiffness of the tangential spring 122 to the spring stiffness of the radial spring 124 lies in a range from 1 to 3. If the spring stiffness of the tangential spring 122 is selected to be greater than that of the radial spring 124, tangential movements are suppressed. This favors movement patterns such as the n = 2 eigenmode, in which the maximum tangential deflection is smaller than the maximum radial deflection. For the same reason, each spring element 120 can also be designed such that less than half the space is available for deflections of the tangential spring 122 in the tangential direction than for deflections of the radial spring 124 in the radial direction. This suppresses, on the one hand, even the translational mode.On the other hand, the space in the tangential direction is not required if the spring elements 120 are adjusted accordingly and can be used for the placement of other components, such as electrodes.

[0056] In particular, the ring structure 110 should oscillate with such a small amplitude, preferably in the range between 0.1 pm and 10 pm, that the spring stiffnesses of the tangential springs 122 and the radial springs 124 remain constant. The spring elements 120 therefore behave like linear springs within the deflection range of the ring structure 110. The linearity of the spring elements 120 is also due to the separation of the tangential springs 122 and the radial springs 124. This separation allows the deflections occurring parallel to the substrate 200 in each direction to be split into a radial and a tangential part and absorbed by the corresponding spring. This prevents parts of the spring elements 120 from being deflected in their preferred directions, i.e., in directions in which they leave the linearity range even with small deflections. This makes the oscillation of the ring structure 110 easier to control.

[0057] The above-described design of the coupling device allows for the effective suppression of excitations of the translational mode compared to excitations of bending modes. The separation of the spring elements 120 into tangential springs 122 and radial springs 124 also allows for a compact design of the spring elements 120, so that the suppression of the translational mode can be achieved together with a compact design of the coupling device 100.

[0058] The spring elements 120 can, in particular, have a radial extension of less than 25% of the radius of the ring structure 110 in the rest state, making the coupling device 100 particularly compact. This makes it possible to place additional components in or around the ring structure 110. The spring elements 120 can be connected to the ring structure 110 from the inside, as shown in Fig. 1A. Due to their compact design, a large part of the interior of the ring structure 110 remains free. However, they can also be connected to the ring structure 110 from the outside, since their small size does not result in an excessive enlargement of the coupling device. This makes it possible to make the interior of the ring structure 110 completely free for the arrangement of additional components, which is not possible, for example, in prior art designs in which the ring structure is held by long, centrally anchored springs or by large frame structures.

[0059] The spring elements 120 can, as shown in Fig. 1A, in principle be distributed irregularly along the ring structure 110 if this is advantageous for the intended suppression of the translational mode. However, the spring elements are preferably distributed evenly in the circumferential direction of the ring structure 110, as this facilitates manufacturing. Furthermore, the ring structure 110 can be excited more easily and homogeneously.

[0060] As shown in Figs. 1A and 1B, each spring element 120 connects the ring structure 110 to the substrate 200 via exactly one anchor structure 125. This avoids anchor losses. These arise when forces are introduced into the substrate via multiple points, which can then only be balanced at the substrate level. The anchor losses describe the energy that is introduced into the substrate by forces and moments at the anchors and dissipates via the substrate into the environment and is thus lost. This can be counteracted by balancing forces and moments and transferring these forces and moments to the substrate at as few and as central points as possible. Accordingly, the use of only one anchor structure reduces the occurrence of such anchor losses.

[0061] As shown in Fig. 1A, the coupling device 110 can include a plurality of spring elements 120. However, the number of spring elements 120 can also vary. For example, 4, 8, 16, 24, or 32 spring elements 120 can be used.

[0062] Figs. 2 to 8 show various variants of spring elements 120. These variants have in common that, in the spring elements 120, the radial spring 124 comprises a double-folded cantilever spring extending in the tangential direction and connected in the radial direction to the substrate 200 and the tangential spring 122. The tangential spring 122 is a cantilever spring folded more than twice or comprises at least two double-folded cantilever springs extending in the radial direction and connected in the radial direction to the radial spring 124 and the ring structure 110. In principle, other configurations are also possible, as long as the tangential spring 122 and the radial spring 124 can be represented separately. For example, it is possible to attach the radial spring 124 to the ring structure and the tangential spring 122 to the substrate 200.

[0063] Fig. 2 shows a spring element 120 in which the radial spring 124 is designed as a double-folded cantilever spring that establishes a connection between an anchor point 125 and the tangential spring 122. This means that a cantilever extending in a tangential direction is connected, preferably at its center, to the anchor structure 125. At each end, the cantilever is folded 360°, i.e., it runs back parallel to the first cantilever, thus forming a second cantilever that runs parallel to the first cantilever. The two cantilevers are connected at their ends. Such a structure can be produced in a conventional manner using an etching process.

[0064] The tangential spring 122 consists of a bending beam spring that runs radially from a (preferably centrally located) connection point with the radial spring 124 to the ring structure 110. At the end of this bending beam spring, a double-folded bending beam spring is connected, which is folded in such a way that it runs in a serpentine manner. The long sides of the serpentines run parallel to the centrally located bending beam spring, i.e., in the radial direction. In the example in Fig. 2, there are three serpentines, with the connection to the radial spring 124 and the ring structure 110 being made at a central location. However, other numbers of serpentines are also possible.

[0065] The deflections of this spring element 120 are shown in a greatly exaggerated form in Figs. 3A and 3B. Fig. 3A shows the deflection in the radial direction r, during which essentially only the radial spring 124 is deformed. Fig. 3B shows the deflection in the tangential direction t, during which essentially only the tangential spring 122 is deformed. By appropriately selecting the dimensions of the cantilever springs that form the tangential spring 122 and the radial spring 124, e.g., by selecting the etching parameters during production, the spring stiffness of the springs can be adjusted independently of one another. The spring element 120 shown in Fig. 2 is also extremely compact. Its use in a coupling device 100, as described above, therefore allows the translational mode to be suppressed without consuming excessive installation space.

[0066] The spring element 120 shown in Fig. 4 corresponds to the design of Fig. 2, except for the use of two double-folded bending beam springs in the radial spring 124. This allows the parameters of the radial spring 124 to be adjusted even more flexibly.

[0067] The spring element 120 shown in Fig. 5 uses fork-shaped pairs of cantilever springs as the tangential spring 122, i.e., pairs of cantilever springs connected at one end and interconnected at the other end. This configuration also allows the spring parameters of the tangential spring 122 and the radial spring 124 to be adjusted independently of one another.

[0068] Figs. 6 and 7 show two variants of a "two-pronged bending beam fork" connected to the radial spring 124 and the ring structure 110, respectively, via a single bending beam. These designs are particularly compact in the tangential direction.

[0069] Fig. 8 shows a variant in which the tangential spring 122 consists of two double-folded cantilever springs connected by a frame to the radial spring 124 and a cantilever spring anchored to the ring structure 110. Furthermore, the radial spring 124, designed as a double-folded cantilever spring, is not continuous here, but merges into the frame.

[0070] The examples in Figs. 2 to 8 should illustrate that there are a multitude of different designs for the spring elements 120, which allow the ratio of the spring stiffness of the tangential spring 122 and the radial spring 124 to be freely adjusted within the framework of the manufacturing conditions in order to suppress the translational mode. Fig. 9 shows a coupling device 100 in which the coupled microelectromechanical components are the spring elements 120. This means that the coupling device 100 corresponds to a deformable ring mounted on a spring above the substrate 200. This can be used as a ring gyroscope 300, since the ring structure 110 is suitable for executing an excitation oscillation, onto which a detection oscillation generated by the Coriolis force is superimposed upon rotation of the ring structure 110. If the ring structure 110 is therefore, e.g.caused to oscillate by the use of excitation electrodes, a rotation of the ring structure 110 leads to a change in this oscillation, which can be read out, e.g. via detection electrodes, in order to determine the rate of rotation.

[0071] Here, the suppression of the translational mode, or the separation of the natural frequency of the translational mode from the operating frequency / excitation frequency of the ring gyroscope 300, is particularly advantageous, as this can reduce measurement interference. This improves the measurement accuracy of the ring gyroscope 300.

[0072] As shown in Fig. 10, several concentric rings connected to each other with short springs, e.g. with short radial bending beams or webs, can also be used as the ring structure 110 of a ring gyroscope 300, e.g. in order to increase the mass of the oscillating ring structure 110.

[0073] As can be seen from Figs. 9 and 10, the spring elements 120 are designed to be compact (less than 1 / 4 of the radius) compared to the dimensions of the ring structure 110 and therefore hardly increase the installation space for the ring gyroscope 300 compared to the ring structure 110 without spring elements 120.

[0074] Electrodes 140 for exciting and / or reading vibrations of the ring structure 110 can be arranged between the spring elements 120, both when used as a ring gyroscope 300 and generally in the circumferential direction of the ring structure 110. This is shown as an example in Fig. 11. In this way, vibrations of the ring structure 110 can be excited or measured in a compact manner. Furthermore, the electrodes 140 can almost completely surround the ring structure 110 in the circumferential direction, thereby achieving a homogeneous response of the ring structure 110. As shown in Fig. 11, the electrodes 140 can be moved relatively close to the tangential springs 122, since these are deflected only comparatively little due to the suppressed translation mode. This improves the interaction between the electrodes 140 and the ring structure 110 and thus the response of the ring structure 110.In addition, the voltage required at the electrodes to apply / read a force is reduced.

[0075] Each of the electrodes 140 can extend circumferentially over an angle of between 10° and 45°, measured from the center of the ring structure 110, depending on the number of spring elements 120 used. An angle range between 15° and 30° has proven preferred, with the use of 10 to 20 spring elements 120. For example, 16 spring elements 120 distributed evenly along the circumferential direction of the ring structure 110 can be used, and the electrodes 140 can each assume an angle of 18°. In this way, 80% of the circumferential direction of the ring structure 110 can be provided with electrodes 140. In general, an arrangement of electrodes 140 in a range of 70% to 90% of the circumferential direction of the ring structure 110 can be considered advantageous for the response behavior of the ring structure 110.

[0076] In the ring gyroscope 300, the angular gain (the ratio of Coriolis mass to twice the modal mass) of the second eigenmode, i.e., the n = 2 eigenmode, of the ring structure 110 may be in a range between 0.3 and 0.4, preferably in a range between 0.35 and 0.4, and more preferably in a range between 0.38 and 0.4 (endpoints included).

[0077] The modal mass describes the proportional mass of the corresponding eigenmode, i.e., the effective mass of the corresponding eigenmode. It results from the eigenvector of the corresponding mode and the mass distribution. The Coriolis mass is composed of all mass points that move in the direction of the exciting oscillation during an excited oscillation and in the direction of the detection oscillation during detection. The so-called "angular gain" can be determined from the ratio of Coriolis mass to modal mass. The theoretical maximum angular gain is 1 (Foucault pendulum). A large angular gain is advantageous and can be understood as the amplification factor of the angular rate signal. Theoretically, the angular gain of a ring gyroscope in the n = 2 eigenmode is 0.4. With the coupling device 100 described above, operated as a ring gyroscope 300, an angular value can be achieved that is extremely close to this theoretical value.This is due to the suppression of the translational mode.< / t> < / t>

Claims

Claims 1. A microelectromechanical coupling device (100) for coupling microelectromechanical components, comprising a flexible ring structure (110) which, at rest, forms a circle, which can be deformed substantially parallel to the plane of the circle and which is suitable for coupling the microelectromechanical components; and a plurality of spring elements (120) which are suitable for connecting the ring structure (110) to a substrate (200); wherein each spring element (120) has at least one tangential spring (122) which can be deflected substantially tangentially to the ring structure (110), and at least one radial spring (124) which can be deflected substantially in the radial direction of the ring structure (110); the tangential spring (122) and the radial spring (124) of each spring element (120) are independent components;and the ratio of spring stiffnesses of the tangential spring (122) and the radial spring (124) of each spring element (120) is designed such that an oscillation deforming the ring structure (110) is energetically more favorable than an oscillation displacing the ring structure (110) translationally and / or rotationally relative to the substrate (200) and / or that the natural frequency of the translational and / or rotational oscillation and the nearest natural frequency of a deforming oscillation have a distance that is greater than 5% of the natural frequency of this deforming oscillation.; 2. Coupling device (100) according to claim 1, wherein the spring elements (120) are designed such that the ratio of the spring stiffness of the tangential spring (122) to the spring stiffness of the radial spring (124) is in a range of 1 to 3.

3. Coupling device (100) according to one of the preceding claims, wherein the ring structure (110) is suitable for being excited to oscillations with an amplitude, preferably in the range between 0.1 pm and 10 pm, in which the spring stiffnesses of the tangential springs (122) and the radial springs (124) remain constant.

4. Coupling device (100) according to one of the preceding claims, wherein the spring elements (120) have a radial extent of less than 25% of the radius of the ring structure (110) in the rest state.

5. Coupling device (100) according to one of the preceding claims, wherein the spring elements (120) are connected to the ring structure (110) from the outside.

6. Coupling device (100) according to one of the preceding claims, wherein each spring element (120) is designed such that less than half the space is available for deflections of the tangential spring (122) in the tangential direction than for deflections of the radial spring (124) in the radial direction.

7. Coupling device (100) according to one of the preceding claims, wherein electrodes (140) for exciting and / or reading vibrations of the ring structure (110) are arranged in the circumferential direction of the ring structure between the spring elements (120).

8. Coupling device (100) according to claim 7, wherein each of the electrodes (140) extends circumferentially over an angle measured from the center of the ring structure (110) between 10° and 45°, preferably over an angle between 15° and 30°, and more preferably over an angle of 18°.

9. Coupling device (100) according to one of the preceding claims, wherein the spring elements (120) are evenly distributed in the circumferential direction of the ring structure (110).

10. Coupling device (100) according to one of the preceding claims, wherein each spring element (120) connects the ring structure (110) to the substrate (200) via exactly one anchor structure.

11. Coupling device (100) according to one of the preceding claims, wherein in each spring element (120) the radial spring (124) comprises a double-folded bending beam spring which extends in the tangential direction and which is connected in the radial direction to the substrate (200) and the tangential spring (122) are connected, and the tangential spring (122) is a more than twice folded cantilever spring or has at least two twice folded cantilever springs which extend in the radial direction and which are connected in the radial direction to the radial spring (124) and the ring structure (110).

12. A ring gyroscope (300) with the micromechanical coupling device (100) according to any one of the preceding claims; wherein the ring structure (110) is adapted to execute an excitation oscillation, upon which a detection oscillation generated by the Coriolis force is superimposed upon rotation of the ring structure (110); and the spring elements (120) represent the microelectromechanical components.

13. Ring gyroscope (300) according to claim 12, wherein the angular gain, ie the ratio of Coriolis mass to twice the modal mass, of the second natural oscillation of the ring structure (110) is in a range between 0.3 and 0.4, preferably in a range between 0.35 and 0.4 and more preferably in a range between 0.38 and 0.4, the endpoints being part of the specified ranges.

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