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EP-4735829-A1 - MICROELECTROMECHANICAL COUPLING DEVICE

EP4735829A1EP 4735829 A1EP4735829 A1EP 4735829A1EP-4735829-A1

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.

Inventors

  • PFEIFFER, JOHANNES

Assignees

  • Northrop Grumman LITEF GmbH

Dates

Publication Date
20260506
Application Date
20240321

Claims (13)

  1. 1. Microelectromechanical coupling device (100) for coupling microelectromechanical components, comprising a flexible ring structure (110) which forms a circle at rest, 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 closest natural frequency of a deforming oscillation have a distance that is greater than 5% of the natural frequency of this deforming oscillation.
  2. 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. 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. 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. 5. Coupling device (100) according to one of the preceding claims, wherein the spring elements (120) are connected from the outside to the ring structure (110).
  6. 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. 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. 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. 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. 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. 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 double-folded cantilever spring or has at least two double-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. 12. Ring gyroscope (300) with the micromechanical coupling device (100) according to one of the preceding claims; wherein the ring structure (110) is suitable for executing an excitation oscillation, on 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. 13. Ring gyroscope (300) according to claim 12, wherein the angular gain, i.e. 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, wherein the end points are part of the specified ranges.

Description

microelectromechanical coupling device The present invention relates to a microelectromechanical coupling device for coupling microelectromechanical components and a ring gyroscope with such a coupling device. In micromechanical measuring devices such as yaw 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. Often, a coupling by means of a freely floating, non-supported ring would be desirable, as this reacts to a radial force with a deflection that has the same amplitude regardless of the point in the circumferential direction at which the radial force is applied. It can also be advantageous to use a freely floating ring as a rotation rate sensor, in which a detection oscillation is superimposed on an excitation oscillation during rotation due to the Coriolis force. The problem here 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. However, these are not desired. In addition, the production of an unsupported ring for coupling microelectromechanical components involves a great deal of effort in terms of production technology. One known example is the use of systems with several rings that are connected to one another by stiff, short connections (so-called spokes). The spokes themselves are very space-saving. However, the need to have several rings in order to obtain the appropriate bearings partially compensates for this space saving. In addition, the spokes do not have resonances in the range of a few kHz due to their stiffness. It is also difficult to achieve homogeneous behavior in the circumferential direction with this structure. Alternatively, extremely long and therefore space-consuming, but also very soft springs are used. Although low resonance frequencies can be achieved with these, the deviations from the ideal ring are very large here too, since homogeneous behavior in the circumferential direction cannot be achieved. 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. This object is solved by the subject matter of claim 1. A microelectromechanical coupling device for coupling microelectromechanical components has a flexible ring structure which forms a circle at rest, 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 which are suitable for connecting the ring structure to a substrate. Each spring element has at least one tangential spring which can be deflected substantially tangentially to the ring structure and at least one radial spring which 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 designed such that an oscillation that deforms the ring structure is energetically more favorable than an oscillation that displaces the ring structure translationally and/or rotationally relative to the substrate and/or that the natural frequency of the translational and/or rotational oscillation and the closest natural frequency of a deforming oscillation have a distance that is greater than 5% of the natural frequency of this deforming oscillation. The distance 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 oscillation. The coupling device therefore has a ring as a basic structure which is mounted above a substrate and has, for example, the shape of a self-contained web, the height of which perpendicular to the substrate is a multiple of its width parallel to the substrate. In the resting position, this ring forms a circle in the broadest sense, ie a closed curve that lies parallel to the substrate. A deformation of the ring is then essentially only possible parallel to the substrate, ie deflections perpendicular to the substrate are negligible for operation. In order to suppress the translational and/or rotational mode or vibration, the ring structure is connected to the substrate via spring elements that are composed of tangential springs and radial springs, i.e. springs that can be deflected essentially tangentially to the ring structure or perpendicularly to the ring structure. The spring stiffnesses of the tangential and radial springs can be adjusted independently of one another by appropriately dimensioning the spr