Micro-electro-mechanical gyroscope with fully differential structure and pitch / roll sensing

Abstract

The invention relates to a micro-electro-mechanical gyroscope with a fully differential structure and pitch / roll sensing. A microelectromechanical gyroscope includes a support body having a major surface parallel to a reference plane defined by a first axis and a second axis perpendicular to each other. The transduction block is constrained to the support so as to be able to oscillate in a drive direction parallel to the first axis and in a third axis perpendicular to the first and second axes. The sensing block is constrained to the support body at a distance from the substrate so as to be able to oscillate in a direction parallel to the second axis. A motion conversion flexure connects the transduction block to a corresponding sensing block and is configured to convert motion of the transduction block along the third axis to motion of the corresponding sensing block along the second axis.

Description

[0001] Priority Declaration

[0002] This application claims the benefit of Italian Patent Application No. 102024000002890, filed on February 12, 2024, the content of which is incorporated herein by reference in its entirety to the maximum extent permitted by law. Technical Field

[0003] The present disclosure relates to a micro-electromechanical gyroscope with a fully differential structure and pitch / roll sensing. Background Art

[0004] It's well known that in the field of microelectromechanical gyroscopes, device designs must meet increasingly stringent market requirements, such as increased scale factor stability and vibration suppression. Applications where scale factor stability and vibration suppression are particularly important include autonomous inertial navigation in the automotive industry. The scale factor defines the gyroscope's sensitivity and should remain stable over the sensor's lifetime. However, external factors such as temperature changes (also during production steps due to soldering on printed circuit boards (PCBs)) or humidity and mechanical stress can affect the scale factor and, therefore, the measurement accuracy.

[0005] In a MEMS gyroscope, the scale factor is directly related to the stationary distance between the fixed or stator sensing electrode and the movable sensing electrode. If the support deforms, the stationary distance between the fixed and movable sensing electrodes changes, and this change affects the sensitivity of the sensor.

[0006] A known solution to the scale factor stability problem envisions a fully differential sensing architecture that compensates for sensitivity variations. In this architecture, each movable sensing electrode is differentially coupled to two corresponding fixed sensing electrodes. This allows pairs of fixed sensing electrodes to be placed at a short distance from their respective associated movable sensing electrodes, minimizing the effects of support deformation. This improves the suppression of common-mode contributions and, consequently, amplifies the differential contribution.

[0007] This solution is readily implemented in gyroscopes that sense rotation about the yaw axis, perpendicular to the support, and typically have a planar sensing structure. In contrast, gyroscopes that sense rotation about the roll or pitch axis have an out-of-plane sensing structure, and the available fully differential architectures can be less satisfactory in some respects. In particular, for the same silicon area occupied, out-of-plane sensing structures have lower sensitivity than in-plane sensing structures because the sensing electrodes are essentially spread out in a plane parallel to the main surface of the support. In contrast, in-plane sensing structures can typically also utilize the spread of the sensing electrodes in a direction perpendicular to the support. Furthermore, as already observed, in-plane sensing structures still have, on average, closer fixed sensing electrodes and are therefore less susceptible to deformations of the support.

[0008] There is a need in the art to provide a micro-electromechanical gyroscope that allows overcoming or at least alleviating the described limitations. Summary of the Invention

[0009] In one embodiment, a microelectromechanical gyroscope includes a support body having a main surface parallel to a reference plane defined by a first axis and a second axis perpendicular to each other. The gyroscope has a plurality of transducer blocks constrained to the support body so as to be able to oscillate along a drive direction parallel to the first axis and along a third axis perpendicular to the first axis and the second axis. The gyroscope has a plurality of sensing blocks constrained to the support body at a distance from a substrate so as to be able to oscillate in a direction parallel to the second axis. The gyroscope has a plurality of motion conversion flexures, each of which connects one of the plurality of transducer blocks to one of the plurality of sensing blocks and is configured to convert motion of one of the plurality of transducer blocks along the third axis into motion of one of the plurality of sensing blocks along the second axis.

[0010] The plurality of transducer blocks may include a first transducer block and a second transducer block, the first transducer block and the second transducer block being arranged symmetrically opposite to each other with respect to a reference axis parallel to the first axis in a stationary state. The gyroscope may include a plurality of first anchors fixed to a support body; and a plurality of oscillation arms, each of the plurality of oscillation arms being supported about a fulcrum by one of the plurality of first anchors so as to oscillate parallel to a reference plane, wherein the fulcrums are aligned along the reference axis at symmetrically opposite positions with respect to central axes of the plurality of transducer blocks parallel to the second axis. The first transducer block and the second transducer block may be supported by the plurality of oscillation arms so as to be movable parallel to the first axis and parallel to a third axis.

[0011] A plurality of oscillation arms may be coupled to the plurality of transduction masses to allow anti-phase motion and prevent in-phase motion of the first and second transduction masses along the first axis. Each of the plurality of oscillation arms may have a first end connected to the first transduction mass and a second end connected to the second transduction mass via a plurality of first suspension flexures, wherein the plurality of first suspension flexures are configured to transmit motion from the first and second ends of the plurality of oscillation arms to the first and second transduction masses in the direction of the first axis.

[0012] Each of the plurality of oscillation arms may be coupled to one of the plurality of first anchors with its fulcrum located symmetrically relative to the intermediate axis. The gyroscope may include a plurality of second anchors and a plurality of second suspension flexures, wherein each of the plurality of sensing masses is supported by one of the plurality of second anchors via one of the plurality of second suspension flexures, and wherein the plurality of second suspension flexures are flexible in the direction of the second axis and rigid in the directions of the first and third axes.

[0013] The plurality of sensing blocks may include a first sensing block and a second sensing block coupled to the first transducer block; and a third sensing block and a fourth sensing block coupled to the second transducer block, wherein the first sensing block and the second sensing block are adjacent to opposite sides of the first transducer block, and the third sensing block and the fourth sensing block are adjacent to opposite sides of the second transducer block. The second sensing block and the third sensing block may form a single rigid body.

[0014] The motion conversion flexure connecting the first transducer mass to the first sensing mass and the second sensing mass can be configured to cause the first sensing mass and the second sensing mass to move in opposite phases in response to displacement of the first transducer mass along the third axis. The motion conversion flexure connecting the second transducer mass to the third sensing mass and the fourth sensing mass can be symmetrical with each other and can be configured to cause the third sensing mass and the fourth sensing mass to move in opposite phases in response to displacement of the second transducer mass along the third axis.

[0015] Each of the plurality of motion-converting flexures may have an elongated shape extending in the direction of a first axis, a first end connected to one of the plurality of transducer masses, and a second end connected to one of the plurality of sensing masses. The first end of each motion-converting flexure may be coupled to its associated transducer mass via a connecting flexure that is rigid along a third axis and bends along a drive direction parallel to the first axis.

[0016] The plurality of motion-converting flexible members may be of a skew type. Each of the plurality of motion-converting flexible members may include a first elastic body, a second elastic body, and a plurality of transverse members. The first elastic body and the second elastic body may be defined by flat rectangular plates that, in a static state, are perpendicular to the second axis and elongated in the direction of the first axis. The first elastic body and the second elastic body may be offset relative to each other in the direction of the second axis and in the direction of a third axis.

[0017] The plurality of transverse elements may be defined by a flat plate in a resting state perpendicular to the first axis. The plurality of transverse elements may be evenly spaced along the first axis. Each transverse element in the plurality of transverse elements may have a first side connected to the first elastomeric body and a second side opposite the first side connected to the second elastomeric body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a better understanding, reference is made to the accompanying drawings, in which embodiments are presented by way of non-limiting examples, in which:

[0019] Figure 1 It is a block diagram of a micro-electromechanical gyroscope;

[0020] Figure 2 yes Figure 1 A top view of the gyroscope's microstructure;

[0021] Figure 3 It is along Figure 2 The line III-III intercepts Figure 2 A cross-section of the microstructure in a first operational configuration;

[0022] Figure 4 Shown Figure 3 a view of the microstructure in a second operational configuration;

[0023] Figure 5 yes Figure 2 A top view of the magnified details of the microstructure;

[0024] Figure 6 yes Figure 5 A partial perspective view of the details;

[0025] Figures 7a-7c They are Figure 5 details of the first cross-section, the second cross-section, and the third cross-section in the first operational configuration; and

[0026] Figures 8a-8c Shown respectively Figures 7a-7c A view in a second operational configuration. DETAILED DESCRIPTION

[0027] The following description relates to the arrangements shown in the accompanying drawings; therefore, expressions such as “above”, “below”, “upper”, “lower”, “top”, “bottom”, “right”, “left” etc. relate to the accompanying drawings and are not to be interpreted in a restrictive manner.

[0028] refer to Figure 1 A microelectromechanical gyroscope according to one embodiment is indicated as a whole by numeral 1 and includes a microstructure 102, a sensing interface 103, an analog-to-digital converter 104, a control unit 105, and a driving stage 108. The sensing interface 103, the analog-to-digital converter 104, the control unit 105, and the driving stage 108 may be components of an application-specific integrated circuit or ASIC (Application Specific Integrated Circuit) 109 coupled to the microstructure 102.

[0029] The sensing interface 103 receives sensing signals from the first sensing terminal 102 a and the second sensing terminal 102 b of the microstructure 2 , respectively, and provides amplified sensing signals, which can be used by the analog-to-digital converter 104 to generate digital sensing signals.

[0030] The control unit 105 processes the digital sense signal and provides an output signal SOUT indicative of the angular velocity about a sense axis (not shown) measured by the microstructure 102 .

[0031] The driving stage 108 is controlled by the control unit 105 and provides a driving voltage VD to maintain the movable part of the microstructure 102 oscillating at a driving frequency ωD, which is constant and close to the resonance frequency of the same microstructure 102 .

[0032] refer to Figure 2-4 The microstructure 102 includes a support 2 , transducer blocks 3 a and 3 b movable relative to the support 2 , and sensing blocks 5 a - 5 d .

[0033] The support body 2 has a main surface 2a that is parallel to a plane XY defined by a first axis X and a second axis Y of a set of three Cartesian axes, and perpendicular to a third axis Z of the set of three Cartesian axes. The support body 2 may include, for example, a substrate 7 and a frame structure 8 formed on the substrate 7 and laterally defining a cavity 10 that accommodates the transducer masses 3a, 3b and the sensing masses 5a-5d. The cavity 10 is also delimited at the bottom by the substrate 7. The substrate 7 and the frame structure 8 are semiconductor materials, such as single-crystal silicon and polycrystalline silicon, respectively.

[0034] The transducer masses 3 a, 3 b and the sensing masses 5 a-5 d, also made of semiconductor material, are elastically connected to the support 2 so as to be able to oscillate according to respective predetermined degrees of freedom relative to a reference axis M, which is parallel to the first axis X (and therefore to the main surface 2 a of the support 2 ) and perpendicular to the sensing axis S. The sensing axis S is the median axis of the transducer masses 3 a, 3 b (in the rest state) and is parallel to the second axis Y.

[0035] Specifically, the transducer blocks include a first transducer block 3a and a second transducer block 3b, which are arranged symmetrically relative to a reference axis M in a stationary state. The first and second transducer blocks 3a and 3b are suspended at a distance from the substrate 7 and supported by an anchor 12 and two oscillating arms 13, allowing them to move relative to the support in a drive direction DD parallel to the first axis X and a transducing direction DT parallel to the third axis Z. In one embodiment, the anchor 12 is positioned along the reference axis M and symmetrically relative to the sensing axis S. The oscillating arms 13, each elongated in the direction of the second axis Y, are also arranged symmetrically relative to the sensing axis S, and each oscillating arm has a first end 13a, a second end 13b, and a fulcrum 13c. The first and second ends 13a, 13b of the oscillating arm 13 are connected to the first and second transducer masses 3a, 3b, respectively, by suspension flexures 15. The suspension flexures are configured to transmit motion from the ends 13a, 13b of the oscillating arm 13 to the transducer masses 3a, 3b in the direction of the first axis X. In contrast, in the direction of the second axis Y, the suspension flexures 15 are substantially rigid, and deformation is limited to facilitate accommodating the motion of the oscillating arm 13. The fulcrums 13c of the oscillating arm 13 are coupled to the respective anchors 12 via suspension flexures 17 and aligned along the reference axis M at positions symmetrically opposed relative to the sensing axis S. The suspension flexures 17 are configured to allow the oscillating arm 13 to oscillate about the respective fulcrums 13a in a plane XY parallel to the major surface 2a. The suspension flexures 17, in turn, prevent translation of the fulcrums 13c in a direction parallel to the first axis X. Thus, the oscillating arm 13 coordinates and allows anti-phase or differential motion of the first transducer mass 3 a and the second transducer mass 3 b parallel to the first axis X (in fact, uncoordinated displacements of equal amplitude, but in opposite directions along the first axis X). Conversely, in-phase or common-mode motion is prevented (i.e., the oscillating arm 13 prevents the first transducer mass 3 a and the second transducer mass 3 b from moving simultaneously in the same direction along the first axis X in a consistent manner).

[0036] The transducer masses 3a, 3b are further provided with movable sensing electrodes 18, for example, capacitively coupled in a comb-like configuration to respective sets of fixed drive electrodes 19a, 19b rigidly anchored to the support 2. Specifically, the movable drive electrodes 18 and the fixed drive electrodes 19a, 19b are shaped and coupled so as to exert an electrostatic force in a drive direction DD on the transducer masses 3a, 3b oriented according to the first axis X in response to a drive voltage VD provided by the drive stage 108. The drive voltage VD is applied to the first transducer mass 3a, 3b with opposite polarity, so that the electrostatic forces are also opposite and cause the first transducer mass 3a, 3b to oscillate in opposite phases at the drive frequency. Due to the drive and the degree of freedom, the transducer masses 3a, 3b convert a rotation about a sensing axis S, which is parallel to the plane XY and perpendicular to the reference axis M, into a motion along a transducing direction DT, which is parallel to the third axis Z. In other words, when the support 2 rotates around the sensing axis at an angular velocity Ω, the transducing masses 3a, 3b oscillate along the third axis Z at a drive frequency ωD and with an amplitude modulated by the angular velocity Ω.

[0037] The identical sensing blocks include a first sensing block 5a and a second sensing block 5b coupled to the first transducer block 3a, and a third sensing block 5c and a fourth sensing block 5d coupled to the second transducer block 3b. The first sensing block 5a and the second sensing block 5b are respectively adjacent to opposite sides of the first transducer block 3a; similarly, the third sensing block 5c and the fourth sensing block 5d are respectively adjacent to opposite sides of the second transducer block 3b. Therefore, in the direction of the second axis Y, the first transducer block 3a is interposed between the first sensing block 5a and the second sensing block 5b; and the second transducer block 3b is interposed between the third sensing block 5c and the fourth sensing block 5d. The second sensing block 5b and the third sensing block 5c are also interposed between the first transducer block 3a and the second transducer block 3b, and in one embodiment, form a single rigid body.

[0038] The sensing masses 5a-5d are suspended at a distance from the substrate 7 and supported by corresponding anchors 20 and suspension flexures 21. In particular, the suspension flexures 21 are flexible in the direction of the second axis Y and are substantially rigid in the directions of the first axis X and the third axis Z. As a result, the sensing masses 5a-5d can move relative to the support 2 in a direction parallel to the second axis Y and the sensing axis S.

[0039] The sensing masses 5a-5d are provided with a movable sensing electrode 22, which is capacitively coupled to a corresponding first and second fixed sensing electrodes 23a, 23b, which are rigidly anchored to the support 2. More precisely, the movable sensing electrode 22 and the fixed sensing electrodes 23a, 23b are defined by a plate or a flat surface perpendicular to the second axis Y and form a capacitor with a variable capacitance depending on the position of the sensing masses 5a-5d relative to the second axis Y. Furthermore, the first and second fixed sensing electrodes 23a, 23b are coupled to a first sensing terminal 102a and a second sensing terminal 102b, respectively, of the microstructure 102.

[0040] The sensing blocks 5a-5d are connected to the corresponding transducer blocks 3a, 3b via a motion conversion flexure 25 having an oblique bend. The motion conversion flexure is configured to convert the motion of the transducer blocks 3a, 3b along the third axis Z into motion of the sensing blocks 5a-5d along the sensing axis S, i.e., motion in a direction parallel to the second axis Y. Oblique bend is the strain that an object can experience when the axis of the applied torque is not aligned with the principal axis of inertia. In this case, the bending plane of the object is misaligned with the stress plane. Oblique bend can be considered to be composed of two straight bends whose torque axes coincide with the principal axis of inertia.

[0041] The motion conversion flexures 25 have an elongated shape in the direction of the first axis X, and each connects a corresponding transducer block 3a, 3b and a corresponding sensing block 5a-5d. More precisely, the motion conversion flexures 25 have a first end connected to the corresponding transducer block 3a, 3b and a second end connected to the corresponding sensing block 5a-5d. In addition, the motion conversion flexures 25 connecting the first transducer block 3a to the first sensing block 5a and the second sensing block 5b are symmetrical with each other and are configured to cause the first sensing block 5a and the second sensing block 5b to move in opposite phases (i.e., with equal amplitudes but opposite directions along the second axis Y) in response to the displacement of the first transducer block 3a along the third axis Z. Similarly, the motion conversion flexures 25 connecting the second transducer block 3b to the third sensing block 5c and the fourth sensing block 5d are symmetrical with each other and are configured to cause the third sensing block 5c and the fourth sensing block 5d to move in opposite phases in response to the movement of the second transducer block 3b along the third axis Z. Furthermore, the motion conversion flexures 25 connecting the second sensing mass 5b to the first transducer mass 3a and connecting the third sensing mass 5c to the second transducer mass 3b are symmetrical with respect to the reference axis M (in a stationary state).

[0042] Specifically, in one embodiment, the first end of the motion-converting flexure 25 is coupled to the corresponding transducer mass 3a, 3b via a connecting flexure 26. The connecting flexure 26 is bent in the direction of the first axis X and rigid in the directions of the second axis Y and the third axis Z. In effect, the connecting flexure 26 transmits the motion of the transducer mass 3a, 3b along the third axis Z to the first end of the corresponding motion-converting flexure 25 in a nearly rigid manner. Thus, the first end of the motion-converting flexure 25 tracks the motion of the corresponding transducer mass 3a, 3b along the transducing direction DT and the third axis Z. Conversely, the connecting flexure 26 permits relative motion of the transducer mass 3a, 3b relative to the motion-converting flexure 25 along a drive direction DD parallel to the first axis X. Consequently, the transducer mass 3a, 3b can oscillate due to drive along the first axis X without changing the state of the motion-converting flexure 25, while motion along the third axis Z is transmitted and converted into corresponding motion along the sensing axis S in a direction parallel to the second axis Y. Recesses 28 obtained in the side surfaces of the transducer masses 3a, 3b and extending longitudinally in the direction of the second axis Y accommodate parts of the connecting flexure 26, which can thus have a desired length and bend according to design preferences.

[0043] In a static state, the first end of the motion conversion flexure 25 is aligned in a direction parallel to the second axis Y.

[0044] Through the arrangement and action of the motion conversion flexure 25 , the sensing blocks 5 a - 5 d , the movable sensing electrode 22 and the fixed sensing electrodes 23 a , 23 b form an in-plane type fully differential sensing structure.

[0045] For example, the motion conversion flexure 25 can be formed substantially as described in U.S. Patent No. 11,993,509 (corresponding to European Patent No. 3,872,451), the contents of which are incorporated herein by reference in their entirety. Hereinafter, for simplicity, reference will be made to only one of the motion conversion flexures 25, e.g., the one that connects the first transducer mass 3 a to the first sensing mass 5 a, although this means that what has been stated also applies to all others.

[0046] Also refer to Figure 5 and Figure 6 The motion conversion flexure 25 includes a first elastic body 30, a second elastic body 31 and a plurality of transverse elements 35, all of which are formed of, for example, the same semiconductor material as the substrate 7 and the frame structure 8, and form a single piece.

[0047] The first elastic body 30 and the second elastic body 31 are defined by flat rectangular plates of the same shape, and are perpendicular to the second axis Y and elongated in the direction of the first axis X in a static state. The first elastic body 30 and the second elastic body 31 are offset relative to each other in the direction of the second axis Y and the direction of the third axis Z. For example, the first elastic body 30 is adjacent to the corresponding transducer block 3a, 3b (for example Figure 6 The first elastic body 30 extends adjacent to the first transducer block 3a in the embodiment and is at a greater distance from the corresponding sensing block 5a-5d (for example, the first sensing block 5a); vice versa, the second elastic body 31 extends adjacent to the corresponding sensing block 5a-5d (here, the first sensing block 5a) and is at a greater distance from the corresponding transducer block 3a, 3b (here, the first transducer block 3a). In addition, the first elastic body 30 is closer to the substrate 7 than the second elastic body 31 (see also FIG. Figure 3 ). For example, in a stationary state, the lower edge of the first elastic body 30 is aligned with the surface of the first transducer block 3a that faces the substrate 7; the upper edge of the second elastic body 31 is aligned with the surface of the first sensing block 5a that faces outward. The dimensions of the first elastic body 30 and the second elastic body 31 along the third axis Z are smaller than those of the transducer blocks 3a, 3b and the sensing blocks 5a-5d. The first elastic body 30 is connected to the corresponding connecting flexible member 26 at the first end of the motion conversion flexible member 25; the second elastic body 31 is connected to the corresponding sensing block 5a-5d (here, the first sensing block 5a) at the second end of the motion conversion flexible member 25.

[0048] The transverse elements 35 are defined by flat plates of identical shape, for example rectangular, which in the rest state are perpendicular to the first axis X. These elements are evenly spaced along the first axis X and have a first side connected to the first elastic body 30 and a second side opposite the first side connected to the second elastic body 31 .

[0049] By way of example, Figures 7a-7c 1 and 2 show cross sections of the motion conversion flexure 25 at the first end, the middle portion and the second end, respectively, along a plane parallel to the plane YZ. Figures 7a-7c In each of the figures, the principal axes of inertia I1, I2 of the corresponding cross-section of the first motion conversion flexure 25 are also shown, assuming that the section has a very small thickness. In particular, in the static state, the principal axes of inertia I1, I2 have the same orientation in each cross-section and are misaligned and transverse relative to the second axis Y and the third axis Z. Figures 7a-7c Also shown are pairs of local axes in the rest state (indicated by Ly'-Lz', Ly"-Lz" and Ly"'-Lz"' respectively), each pair of local axes being formed by axes parallel to the second axis Y and the third axis Z respectively, and passing through the center of gravity of the cross section shown.

[0050] For each cross section of the first motion conversion flexure 25, the centrifugal moment of inertia Ic can be calculated by integration relative to the corresponding pair of local axes:

[0051] I C =∫∫r1r2dA

[0052] where r1 and r2 represent the distances from each point of the cross section to the first and second axes of the pair of local axes, respectively, and dA is the area of the cross section. The centrifugal moment of inertia, Ic, is nonzero because the local axes are not axes of symmetry of the cross section and therefore do not coincide with the principal axes of inertia, I1 and I2. Specifically, the principal axes of inertia, I1 and I2, form angles β with the local axis parallel to the third axis Z and the local axis parallel to the second axis Y, respectively.

[0053] Therefore, if Figures 8a-8c As shown, the force applied to the motion conversion flexible member 25, for example, along the local axis Lz", causes the motion conversion flexible member 25 to bend obliquely. In particular, the force causes deformation along the local axis Lz", which inevitably causes deformation along the local axis Ly". Compared with the static position indicated by the dotted line, in response to the displacement of the first end of the motion conversion flexible member 25 along the third axis Z ( Figure 7a ), the oblique bend causes the rotation and translation of the middle section ( Figure 7b ) and translation of the second end in the direction of the second axis Y. Due to the oblique bending, the movement of the first end of the motion conversion flexure 25 along the third axis Z caused by the transducer masses 3a, 3b in response to the rotation about the sensing axis S is converted into corresponding movement of the second end of the motion conversion flexure 25 and, therefore, the sensing masses 5a-5d along the second axis Y.

[0054] The constraints represented by the suspension flexures 17, 21 and the connecting flexure 26 facilitate the deflection of the motion conversion flexure 25 and the correct movement of the sensing masses 5a-5d.

[0055] When the support 2 rotates about the sensing axis S, the transducer masses 3a, 3b oscillate in anti-phase (i.e., in opposite directions) along the transducing direction DT and the third axis Z at a drive frequency ωD, and the amplitude is proportional to the angular velocity Ω. The motion conversion flexure 25 converts the oscillations of the transducer masses 3a, 3b along the third axis Z into corresponding oscillations of the sensing masses 5a-5d along the second axis Y, which can be read through the capacitive coupling between the movable sensing electrode 22 and the fixed sensing electrodes 23a, 23b. In more detail, the first sensing mass 5a and the second sensing mass 5b oscillate in anti-phase with each other, and the same is true for the third sensing mass 5c and the fourth sensing mass 5d. In addition, the first sensing mass 5a and the fourth sensing mass 5d oscillate in phase with each other. Similarly, the second sensing mass 5b and the third sensing mass 5c oscillate in phase with each other, which is due to the action of the motion conversion flexure 25 and, moreover, obviously due to the fact that they are constrained to form a single rigid body. The motion of the second sensing mass 5b and the third sensing mass 5c will still be in phase even in the absence of a rigid constraint between them.

[0056] Thus, the gyroscope described herein can be used to sense rotations about the pitch or roll axis of the support, and, moreover, a fully differential structure in the plane is also implemented, since the out-of-plane motion of the transducer masses 3a-3b is converted into an in-plane motion of the sensing masses 5a-5d. This therefore allows the advantages of the fully differential structure to be extended also to gyroscopes in which the conversion of rotations initially generates out-of-plane motion (in fact, when rotations about the pitch or roll axis are sensed). In particular, the gyroscope described herein allows improved suppression of common-mode effects and stability of the scale factor after external events (such as thermal or mechanical stresses) that can deform the substrate.

[0057] Finally, it is obvious that modifications and variations may be made to the gyroscope described and illustrated herein without departing from the scope of the present disclosure as defined in the appended claims.

Claims

1. A micro-electromechanical system gyroscope comprising: a support having a major surface parallel to a reference plane defined by a first axis and a second axis perpendicular to each other; a plurality of transducer masses constrained to the support so as to be capable of oscillating along a drive direction parallel to the first axis and along a third axis perpendicular to the first axis and the second axis; a plurality of sensing masses constrained to the support body and spaced a distance from the substrate so as to be capable of oscillating in a direction parallel to the second axis; as well as a plurality of motion conversion flexures, each of which connects one of the plurality of transducer blocks to one of the plurality of sensing blocks and is configured to convert motion of the one of the plurality of transducer blocks along the third axis into motion of the one of the plurality of sensing blocks along the second axis. 2 . The micro-electromechanical gyroscope according to claim 1 , wherein the plurality of transducer blocks include a first transducer block and a second transducer block, the first transducer block and the second transducer block being arranged symmetrically opposite to each other with respect to a reference axis parallel to the first axis in a stationary state.

3. The micro-electromechanical gyroscope according to claim 2, comprising: a plurality of first anchors secured to the support body; as well as a plurality of oscillating arms, each of the plurality of oscillating arms being supported by one of the plurality of first anchors about a fulcrum so as to oscillate parallel to the reference plane, wherein the fulcrum is aligned along the reference axis at positions symmetrically opposite relative to central axes of the plurality of transducer masses parallel to the second axis; The first transducer mass and the second transducer mass are supported by the plurality of oscillation arms so as to be able to move parallel to the first axis and parallel to the third axis. 4 . The micro-electromechanical gyroscope according to claim 3 , wherein the plurality of oscillation arms are coupled to the plurality of transducing masses to allow anti-phase motion and prevent the first and second transducing masses from moving in phase along the first axis.

5. The micro-electromechanical gyroscope according to claim 3 , wherein each of the plurality of oscillating arms has: A first end connected to the first transducer block; and The second end is connected to the second transducer mass through a plurality of first suspension flexures, wherein the plurality of first suspension flexures are configured to transmit motion from the first and second ends of the plurality of oscillation arms to the first and second transducer masses in the direction of the first axis.

6. The micro-electromechanical gyroscope of claim 3, wherein each of the plurality of oscillation arms is coupled to one of the plurality of first anchors, wherein a fulcrum of each oscillation arm is at a symmetrically opposite position relative to the central axis.

7. The micro-electromechanical gyroscope according to claim 3, comprising: a plurality of second anchors; as well as a plurality of second suspension flexures; wherein each of the plurality of sensing blocks is supported by one of the plurality of second anchoring members through one of the plurality of second suspension flexures, and wherein the plurality of second suspension flexures are bendable in the direction of the second axis and rigid in the directions of the first axis and the third axis.

8. The micro-electromechanical gyroscope according to claim 2, wherein the plurality of sensing blocks comprises: a first sensing mass and a second sensing mass coupled to the first transducer mass; as well as a third sensing mass and a fourth sensing mass coupled to the second transducer mass; The first sensing block and the second sensing block are adjacent to opposite sides of the first transducing block, and the third sensing block and the fourth sensing block are adjacent to opposite sides of the second transducing block. 9 . The micro-electromechanical gyroscope according to claim 8 , wherein the second sensing mass and the third sensing mass form a single rigid body.

10. The micro-electromechanical gyroscope according to claim 8, wherein: The motion-converting flexure connecting the first transducer mass to the first sensing mass and the second sensing mass is configured to cause the first sensing mass and the second sensing mass to move in opposite phases in response to displacement of the first transducer mass along the third axis; and The motion conversion flexures connecting the second transducer mass to the third sensing mass and the fourth sensing mass are symmetrical to each other and are configured to cause the third sensing mass and the fourth sensing mass to move in opposite phases in response to displacement of the second transducer mass along the third axis.

11. The micro-electromechanical gyroscope according to claim 8, wherein each of the plurality of motion conversion flexures has: an elongated shape in said direction of said first axis; A first end connected to one of the plurality of transducer blocks; and The second end is connected to one sensing block among the plurality of sensing blocks.

12. The microelectromechanical gyroscope of claim 11 , wherein the first end of each motion-converting flexure is coupled to a transducer mass associated with the motion-converting flexure via a connecting flexure, the connecting flexure being rigid along the third axis and being bendable along the driving direction parallel to the first axis.

13. The micro-electromechanical gyroscope according to claim 1, wherein the plurality of motion conversion flexures are of a bevel type.

14. The micro-electromechanical gyroscope according to claim 1 , wherein each of the plurality of motion-converting flexures comprises: a first elastic body; a second elastic body; as well as multiple lateral elements; in: The first elastic body and the second elastic body are defined by flat rectangular plates, are perpendicular to the second axis and are elongated in the direction of the first axis in a static state; and The first elastic body and the second elastic body are offset relative to each other in the direction of the second axis and in the direction of the third axis.

15. The micro-electromechanical gyroscope according to claim 11, wherein each of the plurality of motion-converting flexures comprises: a first elastic body; a second elastic body; as well as multiple lateral elements; in: The first elastic body and the second elastic body are defined by flat rectangular plates, are perpendicular to the second axis and are elongated in the direction of the first axis in a static state; and The first elastic body and the second elastic body are offset relative to each other in the direction of the second axis and in the direction of the third axis; and Wherein for each of the plurality of motion conversion flexible members: The first elastic body is connected to the associated transducer mass at the first end of the motion conversion flexure; and The second elastic body is connected to the associated sensing mass at the second end of the motion conversion flexure.

16. The micro-electromechanical gyroscope according to claim 14, wherein: said plurality of transverse elements being defined by flat plates at rest perpendicular to said first axis; The plurality of transverse elements are evenly spaced along the first axis; and Each transverse element of the plurality of transverse elements has a first side connected to the first elastic body and a second side opposite the first side connected to the second elastic body.

17. The micro-electromechanical device of claim 15, wherein each actuator comprises: a fixed electrode anchored to the substrate; as well as The movable electrodes intersect with the fixed electrodes to form a capacitive coupling element.

18. The micro-electromechanical device according to claim 17, wherein: The first pair of actuators includes a plurality of rows of the capacitive coupling elements offset in a first direction; and The second pair of actuators includes a plurality of rows of the capacitive coupling elements offset along a second direction perpendicular to the first direction.

19. The micro-electromechanical device of claim 17, wherein the capacitance of each actuator depends on displacement along a single coordinate axis parallel to the substrate.

20. The microelectromechanical device of claim 17, wherein each actuator comprises a plurality of rows of the capacitive coupling elements, wherein the fixed electrodes and the movable electrodes in each row are offset from each other in a direction perpendicular to a direction of the rows.

21. A method of operating a micro-electromechanical system gyroscope, comprising: driving the first transducer block and the second transducer block to oscillate in opposite phases along a driving direction parallel to the first axis at a driving frequency; generating out-of-plane motion of the first and second transducer masses along a third axis perpendicular to both the first and second axes in response to rotation of the microelectromechanical gyroscope about a sensing axis parallel to a second axis perpendicular to the first axis; Converting the out-of-plane motion of the first transducer block and the second transducer block along the third axis into in-plane motion of the sensing block along the second axis through a motion conversion flexible member; as well as The in-plane motion of the sensing mass is sensed by a differential sensing structure to determine the angular velocity of the rotation.

22. The method of claim 21, wherein: The sensing block includes a first sensing block and a second sensing block coupled to the first transducing block, and a third sensing block and a fourth sensing block coupled to the second transducing block; as well as Converting the out-of-plane motion includes: converting the motion of the first transducer mass so that the first sensing mass and the second sensing mass move in opposite phases along the second axis; as well as The motion of the second transducing mass is converted so that the third sensing mass and the fourth sensing mass move in opposite phases along the second axis.

23. The method of claim 22, wherein: the first sensing mass and the fourth sensing mass move in phase with each other along the second axis; and The second sensing mass and the third sensing mass move in phase with each other along the second axis.

24. The method of claim 21 , wherein converting the out-of-plane motion comprises: Applying force to the first end of each motion conversion flexible member to cause the motion conversion flexible member to bend obliquely; as well as In response to the displacement of the first end along the third axis, the displacement of the second end of each motion conversion flexible member along the second axis is generated by the oblique bending.

25. The method of claim 24, wherein: Each motion conversion flexible member includes a first elastic body and a second elastic body offset from each other in the directions of the second axis and the third axis; and The oblique bending includes deformation of the first and second elastic bodies along principal axes of inertia that are not aligned with the second and third axes.

26. The method of claim 21, further comprising: Driving voltages having opposite polarities are applied to the first and second transducing masses to generate electrostatic forces that induce the anti-phase oscillations along the first axis.

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