Stress-relief MEMS gyroscope

Abstract

A MEMS device is provided, comprising: a substrate; a proof mass coupled to the substrate and configured to move along a resonator axis; a drive structure comprising at least one electrode and configured to drive the proof mass to move along the resonator axis; and a pivot link coupled to the proof mass at a first end and a second end of the pivot link, the first end comprising a first fixed pivot and the second end comprising a second fixed pivot, the pivot link comprising: a first lever configured to pivot about the first fixed pivot and a first dynamic pivot; a second lever configured to pivot about the second fixed pivot and a second dynamic pivot; and a third lever configured to pivot about the first dynamic pivot and the second dynamic pivot, wherein the proof mass moves along the resonator axis when the pivot link pivots.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 036,273, filed June 8, 2020, Agent's File No. G0766.70318US00, entitled "Actuator for Driving and Sensing Force Releasing," pursuant to 35 U.S. SC §119(e), the entire contents of which are incorporated herein by reference.

[0003] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 069,656, filed August 24, 2020, Agent's File No. G0766.70328US00, entitled "Stress-Relief MEMS Gyroscope," pursuant to 35 U.S. SC §119(e), the entire contents of which are incorporated herein by reference. Technical Field

[0004] This application relates to kinematic links for inertial sensors in microelectromechanical systems (MEMS). Background Technology

[0005] MEMS devices may include multiple moving masses coupled together by one or more couplers. For example, a gyroscope (sometimes simply called a "gyro") is a rotation-sensitive device and can therefore be used to detect rotation. MEMS gyroscopes typically include a movable body, sometimes called a "sensor mass," to which an electrical signal is applied to generate motion primarily along a specific axis. This is called driving the sense mass, and the axis along which the sense mass is driven is sometimes called the drive axis. As the gyroscope experiences rotation, the sense mass moves additionally along an axis different from the drive axis, sometimes called the sensing axis. Detecting the motion of the sense mass along the sensing axis provides an indication of the rotation experienced by the gyroscope. For some MEMS gyroscopes, driving the sense mass may include moving the sense mass in a plane. For some MEMS gyroscopes, rotation can be detected by sensing the out-of-plane motion of the sense mass. Summary of the Invention

[0006] According to some aspects, a MEMS device is provided, comprising: a substrate; a detection mass coupled to the substrate and configured to move along a resonator axis; a drive structure including at least one electrode and configured to drive the detection mass to move along the resonator axis; and a pivoting link coupled to the detection mass at a first end and a second end, the first end including a first fixed pivot and the second end including a second fixed pivot, the pivoting link including: a first link configured to pivot about the first fixed pivot and a first dynamic pivot; a second link configured to pivot about the second fixed pivot and the second dynamic pivot; and a third link configured to pivot about the first dynamic pivot and the second dynamic pivot, wherein the detection mass is configured to move along the resonator axis when the pivoting link pivots.

[0007] According to some aspects, a MEMS device is provided, comprising: a substrate; a detection mass coupled to the substrate and configured to move along a first axis in response to rotation of the MEMS device; a sensing structure including at least one electrode and configured to move along the first axis; and a pivoting link coupling the sensing structure to the detection mass at a first end and a second end of the pivoting link, the first end including a first fixed pivot and the second end including a second fixed pivot, the pivoting link including: a first link configured to pivot about the first fixed pivot and a first dynamic pivot; a second link configured to pivot about the second fixed pivot and the second dynamic pivot; and a third link configured to pivot about the first dynamic pivot and the second dynamic pivot, wherein the pivoting link is configured to pivot when the detection mass moves along the first axis.

[0008] According to some aspects, a MEMS device is provided, comprising: a detection mass block configured to move along a first axis; a drive structure including at least one electrode and configured to drive the detection mass block along the first axis; and a linkage coupling the detection mass block to the at least one drive structure, wherein the linkage includes: a first lever coupled to the detection mass block at a first end of the first lever; a first spring coupled to the first lever at a second end of the first lever; a second lever coupled to the detection mass block at a first end of the second lever; a second spring coupled to the second lever at a second end of the second lever; wherein the first and second springs are coupled together; and wherein the linkage is configured to pivot about first and second dynamic pivots of the first spring and the first and second dynamic pivots of the second spring. Attached Figure Description

[0009] Various aspects and embodiments of this application will be described with reference to the following accompanying drawings. It should be understood that these figures are not necessarily drawn to scale. Items appearing in multiple figures are indicated by the same reference numerals in all figures in which they appear. For clarity, not every component will be labeled in every drawing.

[0010] Figure 1A-1C This is a schematic diagram of an example MEMS device with a pivoting link according to some non-limiting embodiments.

[0011] Figure 2 The illustration shows some non-limiting embodiments. Figure 1C The motion of an example MEMS device in drive mode.

[0012] Figure 3 The illustration shows some non-limiting embodiments. Figure 1C Example of a MEMS device in sensing mode.

[0013] Figures 4A-4D An example of a three-bar pivot linkage according to some non-limiting embodiments is shown.

[0014] Figure 4E The following is illustrated in normal operating mode according to some non-limiting embodiments. Figures 4A-4D An example of a three-bar pivoting linkage.

[0015] Figure 4F The following is illustrated in tilt operation mode according to some non-limiting embodiments. Figures 4A-4D An example of a three-bar pivoting linkage.

[0016] Figures 5A-5D An example of a four-bar pivot linkage according to some non-limiting embodiments is shown.

[0017] Figure 5E The following is illustrated in normal operating mode according to some non-limiting embodiments. Figures 5A-5D An example of a four-bar pivot linkage.

[0018] Figure 5F The following is illustrated in tilt operation mode according to some non-limiting embodiments. Figures 5A-5D An example of a four-bar pivot linkage.

[0019] Figure 6 Another exemplary four-bar pivot linkage according to some non-limiting embodiments is shown.

[0020] Figure 7 An exemplary five-bar pivot linkage according to some non-limiting embodiments is shown.

[0021] Figure 8An example MEMS gyroscope with four detection mass blocks is shown according to some non-limiting embodiments.

[0022] Figure 9 An example MEMS gyroscope with twelve detection mass blocks is shown according to some non-limiting embodiments.

[0023] Figure 10 This is a block diagram illustrating an example system including a MEMS gyroscope according to some non-limiting embodiments.

[0024] Figure 11 This is a perspective view of a car including an example system with a MEMS gyroscope, according to some non-limiting embodiments. Detailed Implementation

[0025] Various aspects of this application provide microelectromechanical systems (MEMS) devices with kinematic pivoting links that reduce sensitivity to orthogonal, shear, and normal stresses, as well as cubic stiffness. According to some aspects, the pivoting link comprises more than two links, such as three, four, or five links. Each link of the pivoting link can be configured to pivot at a corresponding end of the link.

[0026] A MEMS gyroscope may include at least one detection mass configured to facilitate the detection of angular rate via the detection of a Coriolis force. The Coriolis effect, and the Coriolis force, arise when: (1) the detection mass oscillates; and (2) the gyroscope experiences angular motion. The detection mass may be suspended on a substrate below. In a drive mode, the detection mass is configured to displace along a first axis. The displacement of the detection mass in drive mode can be achieved by one or more drive structures coupled to the detection mass. When the detection mass undergoes angular motion about a second axis, a Coriolis force is generated, resulting in displacement of the detection mass along a third axis. A sensing structure coupled to the detection mass can sense the displacement of the detection mass along the third axis to measure the rotation of the MEMS gyroscope.

[0027] One or more shuttles can facilitate coupling of the detection mass to one or more actuation and sensing structures. Specifically, the one or more actuation and sensing structures can each be coupled to a pivot link, and the pivot link can be coupled to the detection mass via a shuttle. However, in some embodiments, the MEMS gyroscope may not include one or more shuttles, and the pivot link may be directly coupled to the detection mass. The shuttle can suppress misalignment of the actuation and / or sensing patterns by resisting motion orthogonal to the desired motion.

[0028] A pivoting link facilitates motion transfer between the driving and sensing structures and the detection mass, enabling the detection mass to displace in driving mode and detect displacement caused by Coriolis forces in sensing mode. The pivoting link may comprise two segments connected together by a connector, referred to herein as a lever. The lever may also serve as an intermediate structure between the detection mass and the underlying substrate and may be flexible and / or bendable to facilitate motion transfer between the detection mass and the driving and / or sensing structures.

[0029] Gyroscopes of the type described in this article are susceptible to certain error sources that can lead to erroneous detection of rotation and damage the MEMS gyroscope over time. For example, MEMS gyroscopes are susceptible to errors caused by orthogonality, shear and normal stresses, and cubic stiffness. Orthogonality is the detection of the motion of a mass block in a direction orthogonal to the driving motion, ideally 90° out of phase with the Coriolis response. Sources of orthogonality include tilting of the MEMS device and asymmetry in sidewall angles. Orthogonality is generally undesirable because the gyroscope cannot distinguish the electrical signal generated by orthogonality from the electrical signal generated by rotation; therefore, the accuracy of the gyroscope in detecting rotation can be negatively affected by the presence of orthogonality. Normal stress arises from loads applied perpendicular to the component (e.g., tension or compression), while shear stress arises from loads applied parallel to the component (e.g., tilting). Normal stress can cause variations in frequency splitting between the driving and sensing modes, while shear stress can cause variations in the gyroscope's orthogonality signal. Cubic stiffness represents the nonlinearity resulting from spring stiffening due to the extension of a beam (e.g., a pivoting link connector).

[0030] MEMS gyroscopes can be illustrated by using a pivoting link comprising a single connector that couples the levers together. The pivoting link completely reduces or prevents orthogonality. For example, as the shuttle moves linearly away from the pivoting link, the connector bends, allowing the pivoting link to bend. The connector can resist torsion and / or shear, thus suppressing tilting of the pivoting link and preventing orthogonal motion of the gyroscope by suppressing unwanted rotation or tilting of the shuttle and the detection mass connected to it, while allowing desired linear motion.

[0031] However, the inventors have recognized that pivoting links with only two links are susceptible to other error sources, including shear and normal stress susceptibility and cubic stiffness as described herein. The inventors have also recognized that these error sources can be reduced in MEMS devices by implementing kinematic pivoting links with more than two links. For example, in some embodiments, the pivoting link comprises three, four, or five links. Each pivoting link may have a fixed pivot at one end of the pivoting link (e.g., the end connected to the sensed mass) and multiple dynamic pivots between the links of the pivoting link. For example, a three-link link may include at least two dynamic pivots, a four-link link may include at least three dynamic pivots, and a five-link link may include at least four dynamic pivots.

[0032] Each type of pivot link (e.g., three-bar, four-bar, and five-bar) can be implemented using many different designs. Each of the different types and designs of pivot links can address one or more different sources of error (e.g., orthogonal, shear stress, normal stress, cubic stiffness), and the type and design of the pivot link to be implemented can be selected based on the source of error to be addressed.

[0033] Therefore, according to one aspect of this application, a MEMS device is provided, comprising: a substrate; a detection mass coupled to the substrate and configured to move along a resonator axis; a drive structure including at least one electrode and configured to drive the detection mass to move along the resonator axis; and a pivoting link coupled to the detection mass at a first end and a second end, the first end including a first fixed pivot and the second end including a second fixed pivot, the pivoting link including a first rod configured to pivot about the first fixed pivot and a first dynamic pivot; a second rod configured to pivot about the second fixed pivot and the second dynamic pivot; and a third rod configured to pivot about the first dynamic pivot and the second dynamic pivot, wherein the detection mass is configured to move along the resonator axis when the pivoting link pivots.

[0034] In some embodiments, a MEMS device is provided, comprising: a substrate; a detection mass coupled to the substrate and configured to move along a first axis in response to rotation of the MEMS device; a sensing structure including at least one electrode and configured to move along the first axis; and a pivoting link coupling the sensing structure to the detection mass at a first end and a second end, the first end including a first fixed pivot and the second end including a second fixed pivot, the pivoting link including a first link configured to pivot about the first fixed pivot and a first dynamic pivot; a second link configured to pivot about the second fixed pivot and the second dynamic pivot; and a third link configured to pivot about the first dynamic pivot and the second dynamic pivot; wherein the pivoting link is configured to pivot when the detection mass moves along the first axis.

[0035] In some embodiments, a MEMS device is provided, comprising: a detection mass block configured to move along a first axis; a drive structure including at least one electrode and configured to drive the detection mass block along the first axis; and a linkage coupling the detection mass block to the at least one drive structure, wherein the linkage includes: a first lever coupled to the detection mass block at a first end of the first lever; a first spring coupled to the first lever at a second end of the first lever; a second lever coupled to the detection mass block at a first end of the second lever; a second spring coupled to the second lever at a second end of the second lever; wherein the first and second springs are coupled together; and wherein the linkage is configured to pivot about first and second dynamic pivots of the first spring and the first and second dynamic pivots of the second spring.

[0036] The above aspects and embodiments, as well as additional aspects and implementation methods, are further described below. These aspects and / or embodiments may be used alone, together, or in any combination, as the technology is not limited in this respect.

[0037] Figure 1A-1C This is a schematic diagram of an example MEMS device 100 with a pivot link 110 according to some non-limiting embodiments. Specifically, Figure 1AA MEMS device 100 is shown, having a detection mass 102 configured to facilitate angular rate detection. The detection mass 102 may be suspended above and coupled to a substrate (not shown) below. As described herein, the detection mass 102 may be configured to vibrate due to displacements produced by one or more drive structures 104 coupled to the detection mass 102. For example, the detection mass 102 may be configured to move along a first axis (e.g., the x-axis) and a second axis substantially perpendicular to the first axis (e.g., the y-axis). In some embodiments, the detection mass 102 may be configured to move in-plane and / or out-of-plane.

[0038] MEMS device 100 also includes a driving structure 104 and a sensing structure 106. The driving structure is a structure configured to cause movement of a detection mass block 102 of the MEMS device 100. Driving structure 104 may include a driving capacitor, wherein electrostatic force is used to cause movement of the detection mass block 102. For example, driving structure 104 may include a first plurality of electrodes spaced apart from a second plurality of electrodes coupled to an underlying substrate. A voltage may be applied to the second plurality of electrodes, causing a change in the distance between the first and second plurality of electrodes. Therefore, due to the change in the distance between the first and second plurality of electrodes, the driving structure may oscillate in response to the voltage applied to the second plurality of electrodes. Movement of driving structure 104 may be transmitted to detection mass block 102, as further described herein.

[0039] A sensing structure is a structure configured to detect the motion of a detection mass block of a MEMS device 100. For example, sensing structure 106 can sense the motion of detection mass block 102 caused by a Coriolis force generated when detection mass block 102 undergoes angular motion. The motion of detection mass block 102 caused by the Coriolis force can be transmitted to sensing structure 106, causing sensing structure to oscillate as further described herein. Sensing structure 106 may include a sensing capacitor in which an electrostatic force is generated when the distance between electrodes coupled to the sensing structure and electrodes coupled to the underlying substrate changes. The Coriolis translational motion of the detection mass block can be determined based on the electrostatic Coriolis force generated due to angular rotation.

[0040] In the illustrated embodiment, the detection mass block 102 includes two driving structures and two sensing structures. However, any suitable number of driving structures and sensing structures can be implemented and coupled to the detection mass block 102.

[0041] One or more anchors 112 may be provided for coupling components of the MEMS device 100 to an underlying substrate (not shown). For example, in Figure 1A In the illustrated embodiment, an anchor 112 is provided for coupling the driving and sensing structures 104, 106 to the underlying substrate.

[0042] In drive mode, the motion of drive structure 104 can be transmitted to detection mass block 102 via one or more movable shuttles 108. Similarly, in sensing mode, the motion of detection mass block 102 can be transmitted to sensing structure 106 via one or more shuttles 108, such as... Figure 1A As shown. The pivot link 110 includes two segments coupled together by a connector, which is hinged to each shuttle 108 to facilitate motion transmission between the drive and sensing structures 104, 106 and the detection mass block 102. In particular, the movable shuttle 108 may be disposed between the pivot link 110 and the detection mass block 102.

[0043] As described herein, the pivoting link 110 may be configured to have at least three links. That is, the pivoting link may have at least three parts configured to pivot about a pivot at a first and second end of each link. Therefore, a pivoting link with three links includes four pivots: a first fixed pivot and a second fixed pivot located at the first and second ends of the link, and first and third dynamic pivots located between the first and second links and between the second and third links. In some embodiments, each link of the link may be configured to pivot freely relative to the other links of the link.

[0044] As described herein, pivot link 110 may be coupled between the detection mass 102 and the drive structure 104 or sensing structure 106. In a drive operation mode, the drive structure 104 may be oscillated. Motion of the drive structure 104 may be transmitted to the detection mass 102 via pivot link 110 and / or shuttle 108. For example, motion of the drive structure 104 may cause rotation of the rod of pivot link 108, thereby causing pivot link 110 to pivot. Due to the coupling between pivot link 110 and detection mass 102, pivoting of the pivot link may push or pull detection mass 102. Therefore, motion of the drive structure 104 may be transmitted to detection mass 102 via pivot link 100.

[0045] Similarly, pivoting link 110 and / or shuttle 108 can transmit motion of the detection mass 102 to the sensing structure 106. In sensing operation mode, the detection mass 102 can be displaced due to Coriolis forces, as further described herein. Displacement of the detection mass 102 can cause rotation of the rod of pivoting link 110, thereby causing pivoting link 110 to pivot. Due to the coupling between pivoting link 110 and the sensing structure, pivoting of pivoting link 120 can push or pull the sensing structure 106. Therefore, motion of the detection mass 102 can be transmitted to the sensing structure 106 via the pivoting link.

[0046] MEMS device 100 may include a plurality of pivot links 110. For example, MEMS device 100 may include links coupled to one or more drive structures 104 (e.g., such as...). Figure 1A Each of the two drive structures shown in the diagram has a corresponding pivot link. In some embodiments, the MEMS device 100 may include a pivot link coupled to one or more sensing structures 106 (e.g., such as...). Figure 1A Each of the two sensing components 106 shown has a corresponding pivot link 110. In some embodiments, such as... Figure 1A As shown in the illustrated embodiment, the corresponding pivot link 110 can be coupled to each of the drive structure 104 and the sensing structure 106.

[0047] The inventors have recognized that implementing a pivoting link of the type described herein between the verification quality and the actuation or sensing structure of a MEMS device can reduce various forms of stress experienced by the MEMS device (e.g., cubic stiffness, normal stress sensitivity, shear stress sensitivity, and / or orthogonality). Such stress can lead to inaccurate sensing capabilities of the MEMS device. Therefore, the pivoting link described herein provides a MEMS device with improved sensing capabilities.

[0048] Figure 1B-1C An additional example of a MEMS device 100 with a pivot link 110 is shown. For simplicity, Figure 1B The diagram omits the driving and sensing structures 104 and 106. (See diagram 104.) Figure 1B As shown, the pivot link 110 is coupled to the detection mass block 102 via the shuttle 108. One or more anchors 112 are provided for coupling components of the MEMS device 100 to the underlying substrate.

[0049] Figure 1C An example of a MEMS device 100 modified from the shuttle 108 described herein is shown. Figure 1C In the MEMS device, the pivot link 110 is coupled to the driving and sensing structures 104, 106, without using Figure 1A-1B Instead of one or more shuttles as shown, they are directly coupled to the drive and sensing structures 104, 106.

[0050] It should be understood that, for ease of explanation, Figure 1A-1C The pivot link described in [the previous section] has been simplified. Further explanation and details of the pivot link are provided here.

[0051] Figure 2 The illustration shows some non-limiting embodiments. Figure 1CThe example illustrates the motion of a MEMS device in driven mode. The MEMS device 100 may be a MEMS gyroscope configured to detect angular rates by detecting the Coriolis force. In this example, a detection mass 102 is driven to oscillate along the x-axis, and when the detection mass 102 makes angular motion about an out-of-plane axis (e.g., the z-axis) within the page plane, a Coriolis force is generated, causing the detection mass to displace along the y-axis. The MEMS device 100 may be configured to sense the displacement of the detection mass to measure rotation.

[0052] As described herein, the MEMS device 100 may include one or more drive structures 104 configured to drive a detection mass block along the x-axis. Figure 2 In the illustrated embodiment, the MEMS device 100 includes two drive structures 104A and 104B coupled to a sense mass 102 and disposed substantially opposite to each other. Movement of the drive structures 104A and 104B can be transmitted to the sense mass 102 via levers 116A and 116B. These levers can form all or part of the pivoting linkage described herein. A pair of levers 116 can be coupled to a corresponding drive structure 104. When the drive structure 104 oscillates, as... Figure 1B As shown, the pair of levers 116 can pivot about pivot point 117. In some embodiments, as described herein, each lever 116 has multiple pivot points.

[0053] Figure 3 The illustration shows some non-limiting embodiments. Figure 1C Example MEMS device 100 motion in sensing mode. For example... Figure 3 As shown, sensing structures 106A and 106B are configured to sense the motion of the detection mass 102 along the y-axis caused by the Coriolis force, which is generated by the rotation of the detection mass 102 about the z-axis. Therefore, the MEMS device 100 can be configured to sense rotation about an out-of-plane axis (e.g., the z-axis) by the displacement of the detection mass 102 along the y-axis. The motion of sensing structures 106A and 106B can be coupled to the detection mass 102 via levers 116A and 116B. A pair of levers 116 can be coupled to the respective sensing structures 106. When the detection mass 102 oscillates, as... Figure 1C As shown, the pair of levers 116 can pivot about pivot point 117. In some embodiments, as described herein, each lever 116 has multiple pivot points.

[0054] Although in the illustrated embodiment the driving mode is configured along the x-axis and the sensing mode is configured along the y-axis, other configurations are possible. For example, the driving and sensing motion can be along any combination of the x, y, and / or z axes.

[0055] According to aspects of the technology described herein, a MEMS device may include a pivoting link having more than two links. Figures 4A-4D An example of a three-bar pivoting linkage according to some non-limiting embodiments is shown. Figures 4A-4D As shown, the pivoting link 400 includes two segments 116A and 116B (e.g., levers) connected together via a connector 402. Figure 4A In the illustrated embodiment, unlike the two-bar pivot linkage, connector 404 is not directly connected to levers 116A and 116B. Instead, levers 116A and 116B are connected together via a combination of spring 404, insert 406, and connector 402. The inventors have recognized that when connector 402, which allows bending of connecting segments 116A and 116B, is allowed, the connector may harden, leading to undesirable hardening, especially when the connector displacement is on the order of micrometers. This bending can manifest as cubic stiffness, which can cause errors in gyroscope operation.

[0056] The three-bar linkage has additional degrees of freedom compared to the two-bar linkage. Specifically, when the proximal ends of levers 116A and 116B move in the same direction (e.g., by rotating in opposite directions), as... Figure 4A As shown, the additional degree of freedom prevents connector 402 from bending, thus creating cubic stiffness. Specifically, it prevents connector 402 from rotating relative to the detection mass block when the first lever 116A and the second lever 116B rotate in opposite directions. Conversely, spring 404 allows the insert 406 coupled to each lever 116A, 116B to move. The beneficial reduction of orthogonality described with respect to two-bar linkages is still achieved through three-bar linkages, while also reducing or preventing full cubic stiffness.

[0057] The three-bar linkage can also be viewed from its pivot angle. For example, the first segment 116A can be considered the first bar, the second segment 116B can be considered the second bar, and the connector 402 can be considered the third bar. The first bar 116A can be coupled to the detection mass at a first end of the three-bar linkage 400 (e.g., via a spring, or via a shuttle 108 in some embodiments). The first end may include a first fixed pivot 410, wherein the first bar 116A is configured to pivot about the first fixed pivot 410. The second bar 116B can be coupled to the detection mass at a second end of the three-bar linkage 400 (e.g., via a spring, or via a shuttle 108 in some embodiments). The second end may include a second fixed pivot 412, wherein the second bar 116B is configured to pivot about the second fixed pivot 412.

[0058] As described herein, the first and second links 116A and 116B can be coupled together via connector 402. Connector 402 can be configured to pivot relative to the first link 116A about a first dynamic pivot 414. Connector 402 can be configured to pivot relative to the second link 116B about a second dynamic pivot 416. Thus, the first, second, and third links can be configured to pivot relative to each other via the dynamic pivots described herein.

[0059] The pivot can be dynamic because it is positioned between two components configured as pivots. For example, a first dynamic pivot 414 is positioned between a first rod 116A and a connector 402. Both the first rod 116A and the connector 402 are configured to pivot about each other. Conversely, with the first rod 116A coupled to the shuttle 108 at a first fixed pivot 410, only one component (the first rod 116A) is configured to pivot relative to the other component. For example, in some embodiments, the fixed pivot may be positioned at the point where the pivoting component (e.g., the first rod 116A) is coupled to a component (e.g., an anchor 112) fixed relative to the underlying substrate of the MEMS device 100.

[0060] Figure 4B It shows Figure 4A A three-bar linkage 400, wherein the first lever 116A and the second lever 116B rotate in the same direction (e.g., wherein the proximal ends of the first and second levers 116A and 116B move in opposite directions). Figure 4B As shown, when levers 116A and 116B move in opposite directions, the linkage mechanism including 402, 404, and 406 prevents the detection mass block from tilting. Figure 4B As shown, when the first lever 116A and the second lever 116B rotate, the connector 402 does not deform, maintaining the linearity of the mechanical linkage. The connector 402 is sufficiently rigid to resist... Figure 4B The S-shaped bend shown prevents tilting of the detection mass, thus reducing the orthogonality of the gyroscope. Therefore, the three-bar linkage 400 can reduce nonlinearity by lowering the cubic stiffness without affecting the tilt stiffness ratio.

[0061] Figure 4C An example of a three-bar linkage 400 implemented in a MEMS device is shown, wherein the three-bar linkage 400 is coupled to a drive structure 104. Figure 4D Another example of a three-bar linkage 400' is shown, wherein the three-bar linkage 400' is coupled to the drive structure 104.

[0062] The three-bar linkage can be coupled to the drive structure in any suitable manner. Figure 4C In the middle, the three-bar linkage 400 is coupled to the drive structure via two folding springs 408. Figure 4D In the middle, the three-bar linkage is coupled to the drive mechanism via a single spring 410.

[0063] exist Figures 4C-4D In the illustrated embodiment, three levers 400, 400' are coupled to anchor 112. Anchor 112 may be coupled to an underlying substrate (not shown), as described herein. In the illustrated embodiment, each lever 116A, 116B is coupled to a corresponding anchor. However, any suitable number of anchors may be coupled to one or more of levers 116A, 116B. In some embodiments, for example, as Figure 4D As shown, the lever can be coupled to anchor 112 at multiple points.

[0064] exist Figure 4C In the illustrated embodiment, the first and second ends of the three-bar linkage 400 are connected to the detection mass block 102. Figure 4C In the illustrated implementation, the three-bar linkage 400 is directly connected to the detection mass block via a spring 410 without using a shuttle; however, other configurations are also possible.

[0065] In some embodiments, the first and second ends of the three-bar linkage 400 may be coupled to the detection mass block 102 via anchor 112. Thus, the first and second fixed pivots described herein may surround the anchor (e.g., anchor 112).

[0066] Figure 4E The following is illustrated in normal operating mode according to some non-limiting embodiments. Figures 4A-4D An example of a three-bar pivoting linkage. Figure 4F The following is illustrated in tilt operation mode according to some non-limiting embodiments. Figures 4A-4D An example of a three-bar pivoting linkage.

[0067] Figures 5A-5D An example of a four-bar pivot linkage 500 according to some non-limiting embodiments is shown. Figure 5A As shown, the four-bar pivot 500 may include a box spring 502. The respective box springs 502 are connected to the respective levers 116, 116B via corresponding tethers 504 and are connected to each other via connectors 402. In the illustrated embodiment, the four-bar linkage is connected to the drive structure 104 via a single T-connector; however, other configurations are possible. For example, in some embodiments, the four-bar linkage 500 may be coupled to the drive structure 104 via two or more springs.

[0068] The four-bar linkage 500 can be viewed from its pivot angle. For example, a first lever 116A can be considered the first link, a second lever 116B can be considered the second link, and the corresponding box spring 502 can be considered the third and fourth links of the pivoting linkage. As described herein, the first link 116A can be coupled to the detection mass 102 at a first end of the four-bar linkage 500 (e.g., via a spring and / or via an anchor 112) and can be configured to pivot about a first fixed pivot point (not shown). The second link 116B can be coupled to the detection mass at a second end of the four-bar linkage 500 (e.g., via a spring and / or via an anchor 112) and can be configured to pivot about a second fixed pivot point (not shown).

[0069] The first link 116A and the second link 116B can be coupled together via a box spring 502 (e.g., a third link and a fourth link). The third link can be coupled to the first link 116A at a dynamic pivot 510B and is configured to pivot about the dynamic pivot 510B, as... Figures 5B-5C As shown. The fourth link can be coupled to the second link 116B at the second dynamic pivot 510A and is configured to pivot about the second dynamic pivot 510A, as... Figures 5B-5C As shown. The third and fourth links can be coupled together at shared dynamic pivots 510C and 510D and configured to pivot about the shared dynamic pivots 510C and 510D, as... Figures 5B-5C As shown. Therefore, the first, second, third, and fourth links can be configured to pivot relative to each other via the dynamic pivot described herein. The inventors have recognized that the four-bar linkage is beneficial for reducing the sensitivity of MEMS devices to shear stress.

[0070] exist Figure 5A In the illustrated embodiment, the four-bar linkage 500 is coupled to anchor 112. As described herein, the anchor may be coupled to an underlying substrate (not shown). In the illustrated embodiment, each lever 116A, 116B is coupled to a corresponding anchor. However, any suitable number of anchors may be coupled to one or more of levers 116A, 116B. In some embodiments, for example, levers may be coupled to anchors at multiple points.

[0071] Figure 5B It is shown Figure 5A A schematic diagram of the pivot point of the four-bar linkage 500 is shown. Figure 5B As shown, the four-bar linkage 500 has at least two pivot points for each link. Specifically, the springs of the four-bar linkage 500 each include two pivots 510A-D. In the illustrated embodiment, each pivot 510A-D is positioned diagonally opposite to the other spring. As described herein, in some embodiments, the double pivots 510A-D of levers 116A, 116B can be implemented using box springs.

[0072] Figure 5C The coupling with drive structure 104 is shown. Figure 5A The four-bar linkage 500. As described herein, the four-bar linkage 500 can transmit the motion of the drive structure 104 in drive mode to the detection mass of the MEMS device, such that when the four-bar linkage 500 pivots due to the vibration of the drive structure 104, the detection mass is displaced.

[0073] As described herein, the four-bar linkage 500 may be coupled to one or more anchors 112. As shown in the illustrated embodiment, a first lever 116A is coupled to an anchor 112 at a first point 510F, and a second lever 116A is coupled to an anchor 112 at a second point. Points 510F and 510E may act as fulcrums, around which the first and second levers 116A and 116B may pivot. In some embodiments, points 510F and 510 may include the first and second fixed pivots described herein.

[0074] In some embodiments, the drive structure 104 may be coupled to one or more anchors 112. For example, as Figure 5C As shown, the drive structure 104 is coupled to the arm 514 (e.g., via one or more U-shaped springs 516). The arm 514 is then coupled to the anchor 112. For example, as... Figure 5C As shown, arm 514 is coupled to anchor 112 at multiple points. In the illustrated embodiment, drive structure 104 is coupled to two anchors 112; however, drive structure 104 can be coupled to any suitable number of anchors.

[0075] Figure 5D yes Figure 5C An enlarged view of the box spring in the four-bar linkage 500 is shown. Specifically, Figure 5D The first and second dynamic pivots 510A and 510B at the ends of the first and second levers 116A and 116B are shown.

[0076] Figure 5E The following is illustrated in normal operating mode according to some non-limiting embodiments. Figures 5A-5D An example of a four-bar pivot linkage. Figure 5F The following is illustrated in tilt operation mode according to some non-limiting embodiments. Figures 5A-5D An example of a four-bar pivoting linkage. Figure 5E-5F As shown, the double-box spring element of the pivoting link acts as a rigid link in tilt operation mode, thus allowing the link to function as a three-bar system.

[0077] Figure 6 Another example of a four-bar pivot linkage 600 according to some non-limiting embodiments is shown. Figure 6The pivot link 600 comprises four segments, with each lever having two segments. Specifically, the pivot link 600 includes a first lever 116A, a second lever 116B, and a spring 522. Each spring can be connected to each lever 116A and 116B via a cord 520.

[0078] exist Figure 6 In the illustrated embodiment, the four-bar linkage couples levers 116A and 116B together via a drive structure 104. Specifically, each lever 116A and 116B is coupled to the drive structure 104, rather than being directly coupled together. The inventors have recognized that... Figure 6 The four-bar linkage design shown is advantageous for reducing the sensitivity of MEMS devices to packaging stress while also reducing cubic stiffness.

[0079] Each lever 116A, 116B can be coupled to one or more anchors 112. For example, in the illustrated embodiment, each lever 116A and 116B can be connected to a respective anchor 112. In the illustrated embodiment, each lever 116A and 116B is coupled to a respective anchor 112 at multiple points.

[0080] In some embodiments, the drive structure 104 may be coupled to one or more anchors 112. For example, as Figure 6 As shown, drive structure 104 is connected to arm 514 (e.g., via one or more folding springs 524). Arm 514 is then coupled to anchor 112. In the illustrated embodiment, drive structure 104 is coupled to two anchors 112; however, drive structure 104 can be coupled to any suitable number of anchors.

[0081] Figure 7 An example of a five-bar pivot linkage 700 according to some non-limiting embodiments is shown. Figure 7 The five-bar linkage 700 shown is combined Figure 5A-6 The four-bar pivoting linkage shown is an example. For instance, the five-bar pivoting linkage 700 includes corresponding box springs 702 connected to corresponding levers 116A and 116B via tethers 704. Furthermore, the corresponding levers 116A and 116B are connected together via a drive structure, rather than directly connected together, for example, via a connector. Specifically, each box spring 702 is coupled to a spring 706 via tethers 704. Each spring 706 is coupled to a drive structure 104. The inventors have recognized that… Figure 7 The five-bar linkage design shown is advantageous for reducing sensitivity to orthogonal, shear, and normal stresses, as well as nonlinearity caused by increased cubic stiffness.

[0082] The five-bar linkage 700 can also be viewed from its pivot angle. For example, the first lever 116A can be considered the first link, the second lever 116B can be considered the second link, the box spring 702 can be considered the third and fourth links, and the spring 706 and the tether 704 together can be considered the fifth link. The first link 116A can be coupled to the detection mass at a first end of the five-bar linkage 700 (e.g., via the spring and / or anchor 112). The first end may include a first fixed pivot (not shown), in which the first link 116A is configured to pivot about the first fixed pivot. The second link 116B can be coupled to the detection mass at a second end of the four-bar linkage 700 (e.g., via the spring and / or anchor 112). The second end may include a second fixed pivot (not shown), in which the second link 116B is configured to pivot about the second fixed pivot.

[0083] A corresponding box spring 702 can be connected to one of the first and second levers 116A, 116B at the first and second dynamic pivots 714, 716. The corresponding box spring 702 can be connected together by a spring 706 and a tether 704. Each box spring 702 can be connected to the tether 704 at the third and fourth dynamic pivots 718, 720 and configured to pivot about the third and fourth dynamic pivots 718, 720. Therefore, each link of the five-bar linkage 700 can be configured to pivot relative to the other links of the five-bar linkage 700.

[0084] like Figure 7 As shown, the drive structure can be coupled to one or more anchors 112. For example, as Figure 7 As shown, drive structure 104 is coupled to arm 514 (e.g., via a single U-shaped spring 708). Arm 514 is then coupled to anchor 112. In the illustrated embodiment, drive structure 104 is coupled to two anchors 112; however, drive structure 104 can be coupled to any suitable number of anchors.

[0085] As described in this paper, MEMS gyroscopes are susceptible to a number of error sources, including orthogonality, sensitivity to shear and normal stresses, and nonlinearity caused by cubic stiffness. As further described in this paper, different types and designs of pivoting links can reduce or completely eliminate one or more of these error sources.

[0086]

[0087] Table 1: Error Sources in Kinematic Pivot Link Types and Designs

[0088] As shown in Table 1, the pivoting links described in this paper have both advantages and trade-offs. In particular, the pivoting link design with at least three links described in this paper reduces nonlinearity caused by increased cubic stiffness compared to pivoting links with fewer than three links. In some cases, depending on the type of error source that is to be eliminated or reduced, one design may be preferred over another. For example, in some cases, increased orthogonality may be an acceptable trade-off because orthogonality can be electrically accounted for using orthogonal fine-tuning electrodes, which may not be possible for other error sources.

[0089] As described herein, kinematic links and related aspects can be implemented in a MEMS gyroscope (e.g., a MEMS gyroscope configured to sense roll, pitch, and / or yaw rotation). In some embodiments, example MEMS device 100 may form part of a larger MEMS device. Figure 8 An example MEMS gyroscope 800 with four detection mass blocks 802 is shown according to some non-limiting embodiments. In some embodiments, Figure 8 The MEMS gyroscope 800 can be configured to sense rotation around two or more axes. Figure 8 An example of a MEMS gyroscope 800 with four quadrants 804 is shown, the quadrants 804 being coupled together and arranged in a 2x2 configuration. Figure 8 Each quadrant 804 of the MEMS gyroscope may have a detection mass block 802 and one or more pivot links as described herein.

[0090] The detection mass block 802 in each quadrant can be configured to move in the opposite phase relative to adjacent detection mass blocks 802. That is, the detection mass block 802 can be configured in drive mode to move in the opposite direction along a first axis relative to the movement of detection mass blocks vertically and horizontally adjacent to it, and relative to diagonally adjacent detection mass blocks 802. In sensing mode, the detection mass block 802 can be configured to move in the opposite direction along a second axis substantially perpendicular to the first axis relative to the movement of detection mass blocks vertically and horizontally adjacent to it, and in the same direction along the second axis relative to the movement of detection mass blocks diagonally adjacent to it.

[0091] Figure 9 An example MEMS gyroscope 910 with twelve detection mass blocks 802 is shown according to some non-limiting embodiments. Specifically, Figure 9An example of a MEMS gyroscope 910 with three columns 920A, 920B, and 920C is shown, each column configured to sense rotation about a corresponding axis (e.g., pitch, roll, or yaw rotation). In some embodiments, the MEMS gyroscope 910 may be configured to have two columns, wherein one or more columns are configured to sense rotation about multiple axes (e.g., one or more of pitch, roll, and / or yaw rotations). Each column may include at least three detection mass blocks 802, wherein the MEMS gyroscope 910 of the illustrated embodiment has four detection mass blocks per column. Figure 9 The MEMS gyroscope 910 can be implemented with the described pivot link and associated mechanism. For example, in some embodiments, Figure 9 The MEMS gyroscope 910 can implement one or more pivot links as described herein in one or more columns of MEMS gyroscope 910 (e.g., in a column of MEMS gyroscopes configured to sense yaw rotation).

[0092] MEMS devices with pivoting linkages of the type described herein can be deployed in a variety of settings to detect angular rates, including in sports, healthcare, military, and industrial applications. MEMS devices (e.g., MEMS inertial sensors, such as MEMS gyroscopes) can be mounted as wearable sensors deployed in applications monitoring motion-related physical activity and performance, patient health, military personnel activities, or other applications of interest to the user. MEMS gyroscopes can be incorporated into smartphones and configured to sense roll, pitch, and / or yaw rates.

[0093] Figure 10 This is a block diagram illustrating a system 1000, which includes a MEMS device 1002, a power supply unit 1004, a sensing circuit 1006, and an input / output (I / O) interface 1008. In some embodiments, the MEMS device may include any one or a combination of the MEMS devices described herein. In some embodiments, the MEMS device may include a MEMS gyroscope configured to sense roll, pitch, and / or yaw rates.

[0094] System 1000 can periodically transmit data representing the sensed angular rate to an external monitoring system, such as a computer, smartphone, tablet, smartwatch, smart glasses, or any other suitable receiving device, via a wired connection or wirelessly. I / O interface 1008 can be configured to send and / or receive data via Wi-Fi, Bluetooth, Bluetooth Low Energy (BLE), Zigbee, Thread, ANT, ANT+, IEEE 802.15.4, IEEE 802.11ah, or any other suitable wireless communication protocol. Alternatively or additionally, I / O interface 1008 can be configured to send and / or receive data using a proprietary connectivity protocol. I / O interface 1008 may include one or more antennas, such as a microstrip antenna. In some embodiments, I / O interface 1008 can be connected to a cable and can be configured to send and / or receive signals via the cable.

[0095] The power supply unit 1004 can be used to power the system 1000. The power supply unit 1004 can be configured to power some or all of the sensing circuitry 1006, the I / O interface 1008, and / or the MEMS device 1002. In some embodiments, the power supply unit 1004 may include one or more batteries. In at least some embodiments, the system 1000 may consume sufficiently little power to allow it to operate over extended periods based solely on battery power. In some embodiments, the one or more batteries may be rechargeable. The power supply unit 1004 may include one or more lithium-ion batteries, lithium polymer (LiPo) batteries, supercapacitor-based batteries, alkaline batteries, aluminum-ion batteries, mercury batteries, dry cell batteries, zinc-carbon batteries, nickel-cadmium batteries, graphene batteries, or any other suitable type of battery. In some embodiments, the power supply unit 1004 may include circuitry for converting AC power to DC power. For example, the power supply unit 1004 may receive AC power from an external power source (e.g., via the I / O interface 1008) and may provide DC power to some or all components of the system 1000. In this case, the power supply unit 1004 may include a rectifier, a voltage regulator, a DC-DC converter, or any other suitable device for power conversion.

[0096] In some embodiments, the power supply unit 1004 may include an energy harvesting component and / or an energy storage component. Energy can be harvested from and stored from the surrounding environment to power the system 1000 when needed; this may include periodic, random, or continuous power supply. The type of energy harvesting component implemented may be selected based on the expected environment of the system 1000, such as the expected amplitude and frequency of motion that the system 1000 may experience, the stress that the system may experience, the exposure that the system may experience, and / or the temperature that the system may be exposed to, as well as other possible considerations. Examples of suitable energy harvesting technologies include thermoelectric energy harvesting, magnetic vibration harvesting, electro-stress harvesting, photovoltaic harvesting, radio frequency harvesting, and kinetic energy harvesting. In some embodiments, the energy storage component may include a supercapacitor.

[0097] As described above, MEMS devices of the type described herein can be deployed in various settings, such as for detecting angular velocity. One such setting is in a car or other vehicle, such as a ship or an airplane. Figure 11 A vehicle 1100 including system 1000 is schematically illustrated according to some non-limiting embodiments. System 1000 may be disposed at any suitable location within vehicle 1100. In some embodiments, system 1000 may include a package or housing attached to a suitable portion of vehicle 1100, with MEMS devices internally located. In some embodiments, system 1000 may be configured to sense roll, pitch, and / or yaw rates. System 1000 may be configured to provide the sensed angular rates to a computer system disposed within vehicle 1100 and / or to a computer system disposed at a base station external to vehicle 1100 using I / O interface 1008.

[0098] Another application of MEMS devices with pivoting links of the type described herein is as a sensor device for sports applications, such as tennis, swimming, running, baseball, or hockey. In some embodiments, a MEMS device of the type described herein can be a wearable fitness device. In other embodiments, the sensor can be part of a sports device, such as a tennis racket, baseball bat, or hockey bat. Sensing data from the sensor can be used to evaluate a user's performance.

[0099] The aspects of the techniques described herein can provide one or more benefits, some of which have already been described previously. These aspects provide pivoting linkages with at least three links and other aspects for reducing the orthogonality, sensitivity to shear and normal stresses, and cubic stiffness of MEMS devices such as MEMS gyroscopes. It should be understood that not all aspects and embodiments necessarily provide all the benefits described herein. Furthermore, it should be understood that aspects of the techniques described herein can provide additional benefits to those described herein.

[0100] "Substantially in one direction" and "substantially parallel to one direction" should be interpreted herein as parallel to that direction or at an angle of less than 20° relative to that direction, including any value within that range.

[0101] In some embodiments, the terms "approximately" and "about" may be used to indicate ±20% of the target value, within ±10% of the target value in some embodiments, within ±5% of the target value in some embodiments, and still within ±2% of the target value in some embodiments. The terms "approximately" and "about" may include the target value.

Claims

1. A microelectromechanical system (MEMS) device, comprising: Base; A detection mass block is coupled to the substrate and configured to move along the resonator axis; A driving structure, including at least one electrode, is configured to drive the detection mass block to move along the axis of the resonator; and A pivoting link, coupled to the detection mass block at a first end and a second end, the first end including a first fixed pivot and the second end including a second fixed pivot, the pivoting link comprising: The first link is configured to pivot about the first fixed pivot and the first dynamic pivot; The second link is configured to pivot about the second fixed pivot and the second dynamic pivot; and The third link is configured to pivot about the first dynamic pivot and the second dynamic pivot, wherein: The third link includes a first portion configured to pivot about the first dynamic pivot and the third dynamic pivot; and The third link includes a second portion configured to pivot about the second dynamic pivot and the third dynamic pivot, and The detection mass block is configured to move along the resonator axis when the pivoting link pivots.

2. The MEMS device of claim 1, wherein the pivot link is coupled to the drive structure and configured to transmit motion between the drive structure and the detection mass block.

3. The MEMS device of claim 1, wherein when the first and second rods rotate in opposite directions, the third rod is prevented from rotating relative to the detection mass block.

4. The MEMS device of claim 3, wherein the third rod is configured to rotate relative to the detection mass block when the first rod and the second rod rotate in the same direction.

5. The MEMS device of claim 3, wherein the third rod is coupled to the drive structure via at least one spring.

6. The MEMS device of claim 3, wherein the third rod is coupled to each of the first rod and the second rod by one or more tethers.

7. The MEMS device of claim 1, further comprising: At least one sensing structure, including at least one electrode, is configured to move along a second axis substantially perpendicular to the resonator axis; A second pivoting link is coupled to the detection mass block at a first end and a second end, the first end of the second pivoting link including a third fixed pivot, and the second end of the second pivoting link including a fourth fixed pivot. The second pivoting link includes: The first link is configured to pivot about the third fixed pivot and the fourth dynamic pivot; The second link is configured to pivot about the fourth fixed pivot and the fifth dynamic pivot; and The third link is configured to pivot about the fourth and fifth dynamic pivots. The at least one sensing structure is configured to move along the second axis when the second pivot link pivots.

8. A microelectromechanical system (MEMS) device, comprising: Base; A detection mass block is coupled to the substrate and configured to move along the resonator axis; A driving structure, including at least one electrode, is configured to drive the detection mass block to move along the axis of the resonator; and A pivoting link, coupled to the detection mass block at a first end and a second end, the first end including a first fixed pivot and the second end including a second fixed pivot, the pivoting link comprising: The first link is configured to pivot about the first fixed pivot and the first dynamic pivot; The second link is configured to pivot about the second fixed pivot and the second dynamic pivot; and The linkage mechanism is configured to pivot about the first dynamic pivot and the second dynamic pivot, wherein: The linkage mechanism includes a first portion configured to pivot about the first dynamic pivot and the third dynamic pivot. The detection mass block is configured to move along the resonator axis when the pivoting link pivots. The linkage mechanism further includes a second part, the second part comprising: The portion configured to pivot about the second and sixth dynamic pivots; and The portion configured to pivot around the third dynamic pivot and the sixth dynamic pivot.

9. A microelectromechanical system (MEMS) device, comprising: Base; A detection mass block is coupled to the substrate and configured to move along a first axis in response to rotation of the MEMS device; A sensing structure, including at least one electrode, is configured to move along the first axis; and A pivoting link couples the sensing structure to the detection mass block at a first end and a second end, the first end including a first fixed pivot and the second end including a second fixed pivot, the pivoting link comprising: The first link is configured to pivot about the first fixed pivot and the first dynamic pivot; The second link is configured to pivot about the second fixed pivot and the second dynamic pivot; and The third link is configured to pivot about the first dynamic pivot and the second dynamic pivot, wherein: The third link includes a first portion configured to pivot about the first dynamic pivot and the third dynamic pivot; and The third link includes a second portion configured to pivot about the second dynamic pivot and the third dynamic pivot, and The pivot link is configured to pivot when the detection mass block moves along the first axis.

10. The MEMS device of claim 9, wherein the pivot link is coupled to the sensing structure and configured to transmit motion between the sensing mass and the sensing structure.

11. The MEMS device of claim 9, wherein the third rod comprises a spring.

12. The MEMS device of claim 11, wherein the third rod is configured to rotate relative to the detection mass block when the first rod and the second rod rotate along a first direction.

13. The MEMS device of claim 12, wherein when the first rod and the second rod rotate along the first direction, the third rod is configured to rotate along a second direction opposite to the first direction.

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