Three-axis micro-electro-mechanical gyroscope and micro-electro-mechanical gyroscope

Abstract

The utility model relates to a three-axis micro-electro-mechanical gyroscope and a micro-electro-mechanical gyroscope. A microelectromechanical gyroscope includes a die of semiconductor material forming a substrate and a detection structure suspended over the substrate. The detection structure has a main extension in a horizontal plane, is symmetric with respect to the central symmetry axis, and is provided for each gyroscope detection axis with: a first pair of detection masses arranged on a first side of the central symmetry axis; and a second pair of proof masses arranged on a second side of the central symmetry axis, the second side being opposite to the first side in the horizontal plane. The proof masses in each pair are capacitively coupled to a respective stator electrode according to a differential detection scheme. The stator electrodes are symmetrically arranged on opposite sides of the central symmetry axis with respect to each other.

Description

Technical Field

[0001] Embodiments herein relate to a micro-electromechanical gyroscope with improved vibration suppression. In particular, reference is made to a gyroscope of the three-axis type, ie, capable of detecting angular velocity along three orthogonal axes, usually denoted roll, pitch and yaw. Background Art

[0002] As is known, current micromachining techniques allow obtaining microelectromechanical systems (MEMS) starting from a layer of semiconductor material that has been deposited (for example a polysilicon layer) or grown (for example an epitaxial layer) on a sacrificial layer removed via chemical etching. Inertial sensors, accelerometers and gyroscopes obtained with this technique are achieving increasing success, for example in the automotive sector, in inertial navigation or in the field of portable devices for consumer electronics.

[0003] Specifically, a micro-electromechanical gyroscope (hereinafter referred to as a MEMS gyroscope) manufactured using MEMS semiconductor technology is known. This MEMS gyroscope operates on the basis of the relative acceleration theorem using Coriolis acceleration. When a rotation at a certain angular velocity (whose value is to be detected) is applied to a movable mass block driven at a linear velocity, the same movable mass block is subjected to an apparent force called the Coriolis force, which causes it to be displaced in a direction perpendicular to the linear drive velocity and further perpendicular to the axis in which the rotation occurs. The movable mass block is supported via an elastic element that enables the mass block to drive and detect displacement in the direction of the apparent force. According to Hooke's law, the displacement is proportional to the apparent force, so that by detecting the displacement of the movable mass block, the value of the Coriolis force and the rotational angular velocity that generates the Coriolis force can be detected.

[0004] For example, the detection displacement of the movable mass can be capacitively detected by determining the capacitance change caused by the movement of a movable detection electrode under resonant conditions, which movable detection electrode is fixed relative to the movable mass (or consists of part of the same movable mass) and is coupled (for example in a so-called parallel plate configuration, or in a combfingered configuration) to a fixed detection electrode.

[0005] There is a need in the art to provide a MEMS gyroscope, in particular of the three-axis type, having a reduced footprint and a reduced power consumption level and also capable of improving the suppression of vibrations representing disturbances relative to the detection of the angular velocity. Applications that have recently witnessed development and proliferation, for example in the fields of virtual reality (VR) or augmented reality (AR), in fact require more demanding specifications in terms of vibration cancellation, while maintaining an overall size and performance comparable to known sensors, in order to maintain full compatibility with current consumer products.

[0006] However, particularly in the so-called consumer electronics market, the angular velocity sensors commonly used do not have performance characteristics specifically designed to suppress vibrations, particularly vibrations of an angular, non-linear nature, as will be discussed below.

[0007] in this regard, Figure 1 The architecture of a detection structure of a gyroscope of known type is schematically shown (in a cross-sectional view), with reference by way of example to the detection of angular velocity only along one detection axis (e.g. the roll axis), which detection axis corresponds to a first axis (in this example the y-axis) of a horizontal plane xy of a main extension of the same detection structure.

[0008] The detection structure designated by 1 as a whole is symmetrical relative to a central symmetry axis S and includes a pair of detection masses, which are formed by a first detection mass and a second detection mass, respectively represented by M1 and M2. The first detection mass M1 and the second detection mass M2 are arranged on opposite sides relative to the above-mentioned central symmetry axis S and are elastically suspended above the substrate 2.

[0009] On the same substrate 2, a first fixed or stator electrode S1 and a second fixed or stator electrode S2 are arranged in a position facing the above-mentioned first detection mass block M1 and second detection mass block M2 and located below them (along the vertical axis z orthogonal to the above-mentioned horizontal plane); these first fixed electrodes S1 and second fixed electrodes S2 are fixed relative to the substrate 2 and capacitively coupled to the detection masses M1 and M2 in a differential configuration (therefore, the stator electrodes S1 and S2 are also arranged symmetrically relative to the central symmetry axis S, and respectively constitute the positive electrode '+' and negative electrode '-' for the differential detection scheme).

[0010] The detection masses M1, M2 are driven in opposite directions (anti-phase), driving the movement "drive" along a second axis (axis x) of the horizontal plane xy, orthogonal to the above-mentioned first axis, with a linear oscillating movement (thus moving them closer to or alternatively away from the above-mentioned central symmetry axis S).

[0011] In the presence of an angular velocity (designated by Ω) acting about the above-mentioned axis of symmetry, a Coriolis force is generated on the detection masses M1, M2, which causes them to be displaced in relative directions along the vertical axis z (as indicated by the arrows "Co"), for example approaching and respectively moving away from the corresponding stator electrodes S1, S2. A differential capacitance variation is thus generated, which can (after appropriate processing by an electronic circuit of the application-specific integrated circuit (ASIC) type, for example associated with the detection structure 1) provide an indication of the value of the above-mentioned angular velocity Ω.

[0012] The above detection architecture can suppress the vertical axis z (as mentioned above Figure 1 Arrow V inL The linear acceleration of a disturbance (eg due to shock or vibration) acting on the detection structure 1 (indicated by ). Such linear vibrations actually lead to a coincident movement of the detection masses M1, M2 and thus to a capacitance change which is cancelled by differential detection.

[0013] On the contrary, it is clear that the effect of the rotation about the above-mentioned central symmetry axis S and thus the anti-phase movement of the detection masses M1, M2 along the vertical axis z (similar to the movement caused by the above-mentioned Coriolis force) caused by V A The angular acceleration of the disturbance represented (for example again due to vibrations or shocks) is not damped in the detection structure 1 .

[0014] Therefore, the above angular vibrations may affect the detection of the angular velocity of interest, especially when the frequency of the vibrations is close to the driving frequency of the gyroscope or the natural frequency of a spurious mode of the corresponding detection structure.

[0015] To solve the above problems, it has been proposed, for example, to adopt a reduced value of the gyroscope quality factor Q in order to limit the detection and amplification of parasitic outer vibrations. Alternatively, it has been proposed to shift all (operating and parasitic) modes of the gyroscope outside a given frequency band in which vibrations can occur during operation of the same gyroscope.

[0016] However, both solutions have disadvantages.

[0017] In particular, the value of the Q factor is important in determining the performance of the gyroscope, and it is not possible to reduce the Q factor without adversely affecting such performance (eg, in terms of drive capability).

[0018] Furthermore, using higher operating frequencies involves greater stiffness of the elements of the detection structure, thereby reducing sensitivity and increasing the drive voltage required to keep the mass oscillating. In addition, due to changes in the system clock (connected to the operating frequency of the gyroscope), the electronic circuits associated with the detection structure may need to be redesigned.

[0019] Therefore, there is a need to provide a new architecture for a sensing structure for a MEMS gyroscope that will have improved rejection of disturbances, particularly disturbances related to angular vibrations, without suffering from the disadvantages discussed above. Utility Model Content

[0020] The technical problem solved by the utility model is that, in the consumer electronic product market, the angular velocity sensors commonly used do not have performance characteristics specifically used for suppressing vibrations (especially angular and nonlinear vibrations).

[0021] According to one embodiment, the utility model provides a three-axis micro-electromechanical gyroscope, comprising: a tube core of semiconductor material, the tube core comprising a substrate; a detection structure, suspended above the substrate; wherein the detection structure has a main extension in a horizontal plane, and is symmetrical with respect to a first horizontal axis and a second horizontal axis, wherein the first horizontal axis and the second horizontal axis define the horizontal plane; wherein the detection structure comprises: a first roll detection mass block and a second roll detection mass block, which are symmetrically arranged on opposite sides with respect to the first horizontal axis; a first pair of driving masses and a second pair of driving masses, wherein the first pair of driving masses are arranged on the lateral side and outside of the first roll detection mass block, and the second pair of driving masses are arranged on the lateral side and outside of the second roll detection mass block, and the first pair of driving masses and the second pair of driving masses are symmetrical in the horizontal plane with respect to the second horizontal axis; a first pair of pitch detection masses and a second pair of pitch detection masses, wherein the first pair of pitch detection masses are arranged on the lateral side and outside of the first roll detection mass block, and the second pair of pitch detection masses are arranged on the lateral side and outside of the first roll detection mass block The mass is arranged on the lateral side and outside of the second roll detection mass, the first pair of pitch detection mass and the second pair of pitch detection mass are symmetrical in the horizontal plane and relative to the second horizontal axis; wherein each pitch detection mass is coupled to the corresponding driving mass through a corresponding driving elastic coupling element; a first pair of yaw detection elements and a second pair of yaw detection elements are respectively coupled to the first pair of pitch detection mass and the second pair of pitch detection mass; wherein the driving mass is configured to be driven to perform a translational movement in relative directions along the second horizontal axis for each pair of driving mass, and the movement of the driving mass symmetrical to each other relative to the first horizontal axis is also in relative directions; wherein the movement of the driving mass is designed to cause the first roll detection mass and the second roll detection mass to rotate in opposite phase in the horizontal plane, and cause a corresponding translational movement in relative directions along the second horizontal axis of the pitch detection mass pulled by the driving mass; and wherein, in the driving movement, the yaw detection element is rigidly coupled to the corresponding pitch detection mass.

[0022] According to one embodiment, respective roll stator electrodes are arranged below the first and second roll proof masses, capacitively coupled to the respective roll proof masses and positioned on the substrate to provide a differential detection scheme; wherein respective pitch stator electrodes are arranged below the pitch proof masses in each pair of pitch proof masses, capacitively coupled to the respective pitch proof masses and positioned on the substrate to provide a respective differential detection scheme; and wherein the yaw detection element has a basic frame construction, the basic frame construction defining windows internally for movable yaw detection electrodes, the movable yaw detection electrodes alternating with corresponding fixed yaw detection electrodes and capacitively coupled to provide a respective differential detection scheme; wherein in the differential detection scheme, angular velocity about a respective detection axis causes a detectable change in detection capacitance caused by the capacitive coupling to determine a change in an output signal associated with the differential detection scheme, and such that linear vibration or angular vibration does not substantially cause a change in the detection capacitance.

[0023] According to one embodiment, in the presence of said linear or angular vibrations, said first roll proof mass and said second roll proof mass are configured to perform an in-phase rotational movement in said horizontal plane; and further said pitch proof mass is configured to perform a corresponding in-phase movement along said second horizontal axis.

[0024] According to one embodiment, each of the first roll detection mass and the second roll detection mass centrally defines a window, in which a corresponding roll anchor fixedly connected to the substrate is arranged, and a torsion-type elastic anchoring element connects each of the first roll detection mass and the second roll detection mass to the corresponding anchor; wherein, in the presence of a roll angular velocity around the second horizontal axis, the movement of the detection structure is configured to implement an anti-phase rotation of the first roll detection mass and the second roll detection mass outside the horizontal plane around a rotation axis defined by the corresponding elastic anchoring element.

[0025] According to one embodiment, each pitch detection mass block in the first pair of pitch detection mass blocks is coupled to a corresponding pitch detection mass block in the second pair of pitch detection mass blocks arranged symmetrically relative to the first horizontal axis through a corresponding elastic coupling structure, and the corresponding elastic coupling structure extends centrally and intersects with the first horizontal axis; each elastic coupling structure defines an elastic lever element of a center fulcrum type, and the elastic lever element of the center fulcrum type is hinged to the substrate through a central anchor.

[0026] According to one embodiment, in the presence of an angular pitch velocity about the first horizontal axis, the movement of the detection structure is configured to implement anti-phase displacements of the pitch proof masses in each pair of pitch proof masses along a vertical axis, the vertical axis being orthogonal to the horizontal plane, and further to implement anti-phase displacements of each pitch proof mass in the first pair of pitch proof masses and the corresponding pitch proof mass in the second pair of pitch proof masses along the vertical axis due to the rotation of the elastic lever element of the elastic coupling structure about the central anchor outside the horizontal plane.

[0027] According to one embodiment, the pitch detection mass block is arranged outside the roll detection mass block in the horizontal plane, and is coupled together by corresponding elastic coupling structures as a whole to define a rectangular frame in the horizontal plane, and the corresponding elastic coupling structure extends centrally and intersects with the first horizontal axis or the second horizontal axis, and the driving mass block and the roll detection mass block are enclosed in the rectangular frame; each elastic coupling structure defines an elastic lever element of a central fulcrum type, and the elastic lever element of the central fulcrum type is hinged to the substrate through a central anchor.

[0028] According to one embodiment, each driving mass in the first pair of driving masses is coupled to a corresponding driving mass in the second pair of driving masses arranged symmetrically relative to the first horizontal axis through a corresponding elastic coupling element, and the corresponding elastic coupling element extends along the second horizontal axis; and wherein each driving mass in the first pair of driving masses and the second pair of driving masses is centrally coupled to the first roll detection mass and the second roll detection mass, respectively, through a corresponding elastic driving element.

[0029] According to one embodiment, the detection structure further comprises a first pair of yaw detection masses and a second pair of yaw detection masses, wherein the first pair of yaw detection masses and the second pair of yaw detection masses are respectively arranged outside the first pair of pitch detection masses and the second pair of pitch detection masses in the horizontal plane, wherein each yaw detection mass is elastically coupled to a corresponding pitch detection mass by a corresponding yaw elastic coupling element; wherein the yaw detection masses have a basic frame-like structure, wherein the basic frame-like structure internally defines windows for movable yaw detection electrodes, and the movable yaw detection electrodes are alternated with corresponding fixed yaw detection electrodes.

[0030] According to one embodiment, the first roll proof mass and the second roll proof mass are elastically coupled together by an elastic coupling element arranged at the first horizontal axis.

[0031] According to one embodiment, the drive mass is arranged outside the pitch detection mass in the horizontal plane; and wherein the drive mass in each pair of drive masses is elastically coupled by a corresponding elastic coupling structure, which defines an elastic lever element with a central fulcrum, and the central fulcrum is hinged to the substrate by a central anchor.

[0032] According to one embodiment, the pitch proof mass comprises a frame therein, the frame internally defining windows for movable yaw detection electrodes, the movable yaw detection electrodes being fixed relative to the frame and alternating with corresponding fixed yaw detection electrodes, the movable yaw detection electrodes being designed to detect the yaw angular velocity around a vertical axis, the vertical axis being orthogonal to the horizontal plane.

[0033] According to one embodiment, each of the first roll detection mass block and the second roll detection mass block is surrounded by a corresponding annular structure in the horizontal plane, and the corresponding annular structure further couples the pitch detection mass blocks of the first pair of pitch detection mass blocks and the second pair of pitch detection mass blocks together respectively; and a torsion-type elastic central element with a rectangular frame structure is arranged at the first horizontal axis and is configured to elastically couple the elastic annular structures associated with the first roll detection mass block and the second roll detection mass block.

[0034] According to one embodiment, the pitch detection mass in the first pair of pitch detection masses and the second pair of pitch detection masses are coupled to the corresponding annular structure through the corresponding elastic elements at the central part of the corresponding annular structure; therefore, the pitch detection mass in the first pair of pitch detection masses and the second pair of pitch detection masses are inserted between the corresponding driving mass in the first pair of driving masses and the second pair of driving masses and the corresponding one of the first roll detection mass and the second roll detection mass.

[0035] According to one embodiment, the first horizontal axis coincides with the pitch detection axis of the detection structure, and the pitch angular velocity will be detected around the pitch detection axis; the second horizontal axis coincides with the roll detection axis of the detection structure, and the roll angular velocity will be detected around the roll detection axis; and the vertical axis orthogonal to the horizontal plane coincides with the yaw detection axis, and the yaw angular velocity will be detected around the yaw detection axis.

[0036] According to one embodiment, the utility model provides a micro-electromechanical gyroscope, comprising: a tube core of semiconductor material, the tube core comprising a substrate; and a detection structure, which is suspended above the substrate; wherein the detection structure has a main extension in a horizontal plane, is symmetrical relative to a central symmetry axis, and comprises, for each detection axis of the micro-electromechanical gyroscope: a first pair of detection masses, which are arranged on a first side of the central symmetry axis; and a second pair of detection masses, which are arranged on a second side of the central symmetry axis in the horizontal plane, the second side being opposite to the first side; wherein the detection masses in each pair of the first pair of detection masses and the second pair of detection masses are capacitively coupled to corresponding stator electrodes according to a differential detection scheme; and wherein the stator electrodes are symmetrically arranged on opposite sides of the central symmetry axis relative to each other.

[0037] According to one embodiment, the detection mass is configured such that: angular velocities about the respective detection axes cause detectable changes in detection capacitance to determine changes in the output signal associated with the differential detection scheme, the detectable changes in detection capacitance being caused by the capacitive coupling with the stator electrodes; and such that linear or angular vibrations acting about the central symmetry axis do not substantially cause any changes in the detection capacitance.

[0038] According to one embodiment, the proof masses in each pair of proof masses are configured to perform: anti-phase movement due to Coriolis forces associated with angular velocity about the respective detection axis; and in-phase movement due to linear or angular vibrations acting about the central symmetry axis.

[0039] According to one embodiment, a first group of stator electrodes are electrically connected together to form a positive detection electrode for the differential detection scheme, and a second group of stator electrodes are electrically connected together to form a negative detection electrode for the differential detection scheme; wherein the stator electrodes in the first group of stator electrodes are arranged in a centrally symmetrical or axially symmetrical manner relative to the stator electrodes in the second group of stator electrodes.

[0040] According to one embodiment, the detection structure also includes a first pair of driving mass blocks and a second pair of driving mass blocks, wherein the first pair of driving mass blocks and the second pair of driving mass blocks are arranged on opposite sides relative to the central symmetry axis, and are respectively arranged beside and outside the first pair of detection mass blocks and the second pair of detection mass blocks; wherein each driving mass block in the first pair of driving mass blocks is coupled to a corresponding driving mass block in the second pair of driving mass blocks arranged symmetrically relative to the central symmetry axis through a corresponding elastic coupling element of a folding type, and the corresponding elastic coupling element of the folding type extends along an axis perpendicular to the central symmetry axis; and wherein each driving mass block in the driving mass blocks is centrally coupled to a corresponding one of the detection mass blocks through a corresponding elastic driving element.

[0041] According to one embodiment, the central symmetry axis is a first horizontal axis, which coincides with a pitch detection axis of the detection structure, and the pitch angular velocity is detected around the pitch detection axis; the detection structure is further symmetrical with respect to a second horizontal axis, which together with the first horizontal axis forms the horizontal plane, and which coincides with a roll detection axis of the detection structure, and the roll angular velocity is detected around the roll detection axis; the detection structure further has an extension portion along a vertical axis that is smaller than the main extension portion, the vertical axis is orthogonal to the horizontal plane and coincides with a yaw detection axis, and the yaw angular velocity is detected around the yaw detection axis.

[0042] According to one embodiment, the first pair of proof masses and the second pair of proof masses include a first pair of roll proof masses and a second pair of roll proof masses, the first pair of roll proof masses and the second pair of roll proof masses being symmetrically arranged on opposite sides with respect to the first horizontal axis; wherein respective roll stator electrodes arranged below the roll proof masses in the first pair of roll proof masses and the second pair of roll proof masses are capacitively coupled to the respective roll proof masses and positioned on the substrate to provide the differential detection scheme; and wherein the roll proof masses in each pair of the first pair of roll proof masses and the second pair of roll proof masses are fixedly coupled together to form a single body and centrally define a window in which respective roll anchors fixedly connected to the substrate are arranged, and wherein torsion-type elastic anchoring elements connect the roll proof masses in each pair of the first pair of roll proof masses and the second pair of roll proof masses to the respective anchors.

[0043] According to one embodiment, the micro-electromechanical gyroscope also includes a first pair of driving masses and a second pair of driving masses, wherein the first pair of driving masses and the second pair of driving masses are arranged on opposite sides relative to the first horizontal axis, beside and outside the roll detection masses in the first pair of roll detection masses and the second pair of roll detection masses, respectively; wherein each driving mass in the first pair of driving masses is coupled to a corresponding driving mass in the second pair of driving masses arranged symmetrically relative to the first horizontal axis x through a corresponding elastic coupling element of a folding type, and the corresponding elastic coupling element of the folding type extends along the second horizontal axis; and wherein each driving mass in the driving masses is centrally coupled to a corresponding one of the roll detection masses in the roll detection masses through a corresponding elastic driving element.

[0044] According to one embodiment, the micro-electromechanical gyroscope further comprises a first pair of pitch detection masses and a second pair of pitch detection masses, wherein the first pair of pitch detection masses and the second pair of pitch detection masses are respectively arranged beside and outside the roll detection masses in the first pair of roll detection masses and the second pair of roll detection masses on opposite sides relative to the first horizontal axis; wherein corresponding pitch stator electrodes are arranged below the pitch detection masses in each pair of the first pair of pitch detection masses and the second pair of pitch detection masses, and are capacitively coupled to the corresponding pitch detection masses and positioned on the substrate to provide corresponding differential detection schemes; wherein each pitch detection mass is coupled to the corresponding driving mass through a corresponding elastic coupling driving element.

[0045] According to one embodiment, the drive mass is configured to be driven to perform anti-phase translational movement along the second horizontal axis for each pair of drive mass masses, and the mutually symmetrical movements of the drive mass masses relative to the first horizontal axis are anti-phase; wherein the movement of the drive mass is designed to cause anti-phase rotation of the roll detection mass masses in the first pair of roll detection mass masses and the second pair of roll detection mass masses in the horizontal plane around an axis parallel to the vertical axis and passing through the center of the corresponding roll anchor; and wherein the pitch detection mass mass is carried by the drive mass mass to perform a corresponding anti-phase translational movement along the second horizontal axis.

[0046] According to one embodiment, the pitch detection mass block is arranged outside the driving mass block in the horizontal plane and is coupled together by corresponding elastic coupling structures as a whole to define a rectangular frame in the horizontal plane, and the corresponding elastic coupling structure extends centrally and intersects with the first horizontal axis or the second horizontal axis, and the driving mass block and the roll detection mass block are enclosed in the rectangular frame; each elastic coupling structure defines an elastic lever element of a central fulcrum type, and the elastic lever element of the central fulcrum type is hinged to the substrate through a central anchor.

[0047] According to one embodiment, the micro-electromechanical gyroscope further comprises a first pair of yaw detection masses and a second pair of yaw detection masses, wherein the first pair of yaw detection masses and the second pair of yaw detection masses are respectively arranged outside the pitch detection masses in the first pair of pitch detection masses and the second pair of pitch detection masses on opposite sides relative to the first horizontal axis; wherein each yaw detection mass is elastically coupled to the corresponding pitch detection mass by a corresponding yaw elastic coupling element; wherein, during the driving movement, the yaw detection mass is fixedly coupled to the corresponding pitch detection mass.

[0048] According to one embodiment, the yaw proof mass has a substantially frame-like configuration defining internally windows for movable yaw detection electrodes alternating with corresponding fixed yaw detection electrodes.

[0049] According to one embodiment, the pitch proof mass comprises a frame therein, the frame internally defining windows for movable yaw detection electrodes, the movable yaw detection electrodes being fixed relative to the frame and alternating with corresponding fixed yaw detection electrodes, the movable yaw detection electrodes being designed for detecting the yaw angular velocity about the vertical axis.

[0050] According to one embodiment, the drive mass is arranged outside the pitch detection mass in the horizontal plane; and wherein the drive masses in each of the first pair of drive masses and the second pair of drive masses are elastically coupled by corresponding elastic coupling structures, and the corresponding elastic coupling structures define an elastic lever element with a central fulcrum, and the central fulcrum is hinged to the substrate by a central anchor.

[0051] According to one embodiment, the roll detection masses in each pair of the first pair of roll detection masses and the second pair of roll detection masses are surrounded by corresponding annular structures in the horizontal plane, and the corresponding annular structures further couple the pitch detection masses in each pair of the first pair of pitch detection masses and the second pair of pitch detection masses together; and wherein an elastic central element of a torsion type having a rectangular frame configuration is arranged at the first horizontal axis and is configured to elastically couple the elastic annular structures associated with the first pair of roll detection masses and the second pair of roll detection masses.

[0052] The utility model provides a new architecture of a detection structure for a MEMS gyroscope, and the technical effect thereof lies in reduced area occupation, lowered power consumption level and improved disturbance (especially disturbance related to angular vibration) suppression. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to better understand the present invention, preferred embodiments thereof will now be described by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0054] Figure 1 is a schematic cross-sectional illustration of a portion of a sensing structure of a MEMS gyroscope of known type with reference to a sensing axis;

[0055] Figure 2 is a schematic cross-sectional illustration of a portion of a detection structure of a MEMS gyroscope according to one aspect of the present solution with reference to a detection axis;

[0056] Figure 3 is a detailed top view of the detection structure of the three-axis MEMS gyroscope according to the first embodiment;

[0057] Figure 4 yes Figure 3 A schematic top view of the detection structure with reference to the driving movement;

[0058] Figure 5A yes Figure 3 The detection structure of the detection structure refers to a schematic top view of the rolling detection movement;

[0059] Figure 5B yes Figure 5A A schematic cross-sectional illustration of a portion of a detection structure with reference to an ability to suppress linear vibration or angular vibration in a roll detection mode;

[0060] Fig. 6A yes Figure 3 A schematic top view of the detection structure of the pitch detection movement with reference to the pitch detection;

[0061] Figure 6B yes Fig. 6AA schematic cross-sectional illustration of a portion of a detection structure with reference to the ability to suppress linear vibration or angular vibration in a pitch detection mode;

[0062] Fig. 7A yes Figure 3 The detection structure of the reference yaw detection movement schematic top view;

[0063] Figure 7B yes Fig. 7A A schematic top view of a portion of a detection structure with reference to the ability to suppress linear vibration or angular vibration in a yaw detection mode;

[0064] Figure 8 is a detailed top view of a detection structure of a three-axis MEMS gyroscope according to a second embodiment;

[0065] Fig. 9 yes Figure 8 A schematic top view of the detection structure with reference to the driving movement;

[0066] Fig.10 yes Figure 8 The detection structure of the detection structure refers to a schematic top view of the rolling detection movement;

[0067] Fig.11 yes Figure 8 A schematic top view of the detection structure of the pitch detection movement with reference to the pitch detection;

[0068] Fig. 12A yes Figure 8 A schematic top view of the detection structure of FIG. 1 with reference to the yaw detection movement; and

[0069] Fig. 12B yes Fig. 12A Schematic top view of a portion of a detection structure with reference to the ability to suppress linear vibrations or angular vibrations in yaw detection mode. DETAILED DESCRIPTION

[0070] like Figure 2 Schematically illustrated (with reference to possible detection axes by way of example), according to one aspect of the present solution, the architecture of the detection structure of the MEMS gyroscope comprises, for each detection axis, two pairs of detection masses, which are arranged symmetrically with respect to a central symmetry axis S around which the angular oscillations of the disturbance may occur.

[0071] The detection structure designated by 10 therefore comprises in this case: a first pair of detection masses, indicated by M1, M2, arranged on a first side of the central symmetry axis S; and a second pair of detection masses, indicated by M1', M2', arranged on a second side of the central symmetry axis S, which second side is opposite to the above-mentioned first side (in the horizontal plane xy).

[0072] The proof masses in each pair M1, M2, M1', M2' are connected according to a differential detection scheme designed to generate an electrical output signal S after appropriate processing of the resulting capacitance changes. out ) are capacitively coupled to the corresponding stator electrodes S1, S2, S1', S2', so that the stator electrodes are arranged in a centrally symmetrical manner, in pairs symmetrically on opposite sides of the central symmetry axis S, and respectively constitute a positive electrode '+' (in the example, the stator electrodes S1, S1' are arranged in a position farther away from the central symmetry axis S and are electrically connected together) and a negative electrode '-' (in the example, the stator electrodes S2, S2' are arranged in a position closer to the central symmetry axis S and are electrically connected together) to implement a differential detection scheme.

[0073] Basically, the stator electrodes defining the above-mentioned positive electrodes and the stator electrodes defining the above-mentioned negative electrodes are arranged in pairs in a symmetrical manner.

[0074] Due to the differential detection scheme, this configuration of the proof mass not only suppresses the perturbed linear acceleration (again from the above Figure 2 Arrow V in L Indicated by V A ), which in fact produces a consistent movement of the proof masses in each pair on each side of the central symmetry axis S (as opposed to the anti-phase movement due to the Coriolis force), thereby generating an output signal S out The zero-result effect.

[0075] As the same Figure 2 As indicated, the proof masses in each pair are suitably driven in anti-phase by the drive movement so as to generate forces and corresponding movements opposite to each other on each side of the central symmetry axis S by the Coriolis effect.

[0076] The detection masses M1, M1' arranged in a position further away from the central symmetry axis S have, at the represented moment, a detection movement (again indicated by arrow Co) in a first direction along the vertical axis z (in the example, a movement close to the corresponding stator electrodes S1, S1'), while the detection masses M2, M2' arranged in the example in a position closer to the central symmetry axis S have a detection movement in a second direction along the vertical axis z opposite to the first direction (in the example, a movement away from the corresponding stator electrodes S2, S2').

[0077] Thus, the arrangement of the detection mass and the corresponding stator electrode and the differential configuration of the capacitive coupling to the same stator electrode advantageously enables the generation of the output signal S out , the output signal S out Indicates the angular velocity of interest about the corresponding detection axis and is insensitive to linear vibration disturbances or angular vibration disturbances.

[0078] First refer to Figure 3 , a first embodiment of a sensing structure (again designated by 10) of a MEMS gyroscope 100 of the three-axis type is now described in more detail, in which the previously described architecture is employed for each of the sensing axes (i.e., roll, pitch and yaw) to obtain the desired improved suppression of (linear and / or angular) vibration disturbances.

[0079] The detection structure 10 is provided in a die 101 of a semiconductor material (e.g. silicon) comprising a substrate 11, is suspended above the substrate 11, and has complete symmetry with respect to a first central axis, which coincides with a first horizontal axis x of a horizontal plane xy of a main extension of the detection structure 10. Specifically, the first horizontal axis x coincides with a pitch detection axis of the detection structure 10, about which a pitch angular velocity Ω can be detected. p .

[0080] The detection structure 10 is also completely symmetrical with respect to the second horizontal axis y, which together with the first horizontal axis x forms the horizontal plane xy and coincides with the roll detection axis of the detection structure 10, around which the roll angular velocity Ω can be detected. r .

[0081] The detection structure 10 has an extension (thickness) smaller than the main extension along the vertical axis z, which is orthogonal to the horizontal plane xy and coincides with the yaw detection axis around which the yaw angular velocity Ω can be detected. y .

[0082] The detection structure 10 includes a first pair of roll detection masses R1, R2 and a second pair of roll detection masses R1', R2', which are symmetrically arranged on opposite sides with respect to a first horizontal axis x and suspended above the substrate 11 with a certain separation distance along the vertical axis z.

[0083] In this embodiment, the roll proof masses R1, R2, R1', R2' in each pair are fixedly coupled together to form a single body (thereby jointly defining a first roll proof mass R1, R2 formed by a first pair of roll proof masses and a second roll proof mass R1', R2' formed by a second pair of roll proof masses, these first and second roll proof masses being arranged on opposite sides of a first horizontal axis x). The single body defined above has a substantially rectangular extension along the second horizontal axis y and centrally defines a window 13, within which a respective roll anchor 14 fixedly connected to the substrate 11 is arranged (the roll anchor 14, for example, has a substantially columnar configuration extending to the substrate 11, being integrally coupled to the same substrate 11).

[0084] Elastic anchoring elements 15 of the torsion type connect the roll proof masses R1, R2, R1', R2' of each pair to the corresponding anchors 14 in the windows 13. In particular, these elastic anchoring elements 15 have a longitudinal extension along a first horizontal axis x and are arranged on opposite sides of the roll anchors 14 relative to a second horizontal axis y.

[0085] Multiple pairs of roll detection masses R1, R2, R1', R2' are elastically coupled together by an elastic coupling element 15', which is arranged in a position corresponding to the first horizontal axis x and has stiffness, such as allowing movement of the two masses along the first horizontal axis x and along the vertical axis z, and at the same time, such as keeping them constrained to each other.

[0086] The corresponding rolling stator electrode S R 1. S R 2. S R 1', S R 2' (schematically illustrated) is arranged below the roll proof mass R1, R2, R1', R2' in each pair, capacitively coupled to the respective roll proof mass R1, R2, R1', R2', and positioned on the substrate 11 (so as to provide a differential detection scheme, as previously described with reference to Figure 2 discussed).

[0087] The detection structure 10 also includes a first pair of driving masses D1, D2 and a second pair of driving masses D1', D2', which are respectively arranged beside and outside the rolling detection masses R1, R2, R1', R2' in the first pair and the second pair on opposite sides relative to the first horizontal axis x, and are also suspended above the substrate 11 at a certain separation distance along the vertical axis z.

[0088] The above driving masses D1, D2, D1', D2' have, for example, a substantially rectangular frame structure along the second horizontal axis y, defining internally a window 16 for a movable driving electrode 17, which is fixed relative to the frame and is in a comb-shaped shape with a corresponding fixed driving electrode (not shown for reasons of clarity), which is also arranged in the same window 16.

[0089] By means not shown in detail, in the frame of the drive masses D1 , D2 , D1 ′, D2 ′, further electrodes for detecting the drive movement may be provided, which are designed to provide a feedback indication of the drive movement.

[0090] Each driving mass D1 , D2 of the first pair is coupled to a respective driving mass D2 ′, D1 ′ of the second pair (arranged symmetrically with respect to the first horizontal axis x) by a respective elastic coupling element 18 of folded type having an extension along the second horizontal axis y.

[0091] The drive masses D1, D2, D1', D2' are coupled via respective elastic anchoring elements 20, also of folding type, to respective drive anchors 19, which are fixed relative to the substrate 11 and arranged at the opposite side relative to the respective elastic coupling elements 18, i.e. at a certain distance from the first horizontal axis x.

[0092] Each of the driving masses D1, D2, D1', D2' is further centrally coupled to a respective one of the rolling detection masses R1, R2, R1', R2' via a respective elastic drive element 21 of torsion type having a linear extension oriented longitudinally along the first horizontal axis x.

[0093] Moreover, the detection structure 10 includes a first pair of pitch detection masses P1, P2 and a second pair of pitch detection masses P1', P2', which are respectively arranged beside and outside the driving masses D1, D2, D1', D2' in the first pair and the second pair on opposite sides relative to the first horizontal axis x, and are also suspended above the substrate 11 at a certain separation distance along the vertical axis z.

[0094] The above pitch detection masses P1 , P2 , P1 ′, P2 ′ are, for example, substantially L-shaped, with long sides extending along the second horizontal axis y and short sides extending along the first horizontal axis x.

[0095] As discussed for the roll proof masses, arranged below the pitch proof masses P1, P2, P1', P2' in each pair are respective pitch stator electrodes S P 1. S P 2. S P 1', S P 2' (schematically illustrated), which is capacitively coupled to the respective pitch proof masses P1, P2, P1', P2' and positioned on the substrate 11 (so as to provide a differential detection scheme, as previously described with reference to Figure 2 discussed).

[0096] Each pitch detection mass P1, P2, P1', P2' is coupled to a corresponding driving mass D1, D2, D1', D2' via a corresponding driving elastic coupling element 22, which has an extension along the second horizontal axis y, folded ends and a central part with a linear extension. Figure 3In the illustrated embodiment, each pitch detection mass P1, P2, P1', P2' is coupled to a corresponding driving mass D1, D2, D1', D2' by means of two corresponding driving elastic coupling elements 22, which are connected to the corresponding ends of the long sides of the same pitch detection mass P1, P2, P1', P2'.

[0097] In addition, the pitch detection masses P1, P2, P1', P2' are coupled together in pairs by corresponding elastic coupling structures 25, which extend centrally between the corresponding ends of the long sides or short sides of the pitch detection masses P1, P2, P1', P2' and cross the first horizontal axis x or the second horizontal axis y. Figure 3 It is obvious from the inspection that the pitch detection masses P1, P2, P1', P2' and the above-mentioned elastic coupling structure 25 as a whole define a rectangular frame, and the driving masses D1, D2, D1', D2' and the roll detection masses R1, R2, R1', R2' are enclosed in the rectangular frame.

[0098] In detail, each elastic coupling structure 25 defines an elastic lever element 26 of central fulcrum type, which is hinged to the substrate 11 through a central anchor 27 and is coupled at its ends to the corresponding pitch detection mass blocks P1, P2, P1', P2' by means of corresponding folded elastic elements 28.

[0099] In this embodiment, the detection structure 10 also includes a first pair of yaw detection masses Y1, Y2 and a second pair of yaw detection masses Y1', Y2', which are arranged on the outside of the pitch detection masses P1, P2, P1', P2' in the first pair and the second pair on opposite sides relative to the first horizontal axis x, respectively, and are suspended above the substrate 11 at a certain separation distance along the vertical axis z.

[0100] Each yaw proof-mass Y1, Y2, Y1', Y2' is elastically coupled to a respective pitch proof-mass P1, P2, P1', P2' via a respective yaw elastic coupling element 29 having an extension along the first horizontal axis x (in a position arranged between the same pitch proof-mass and yaw proof-mass), with folded ends and a central portion with a linear extension.

[0101] The above-mentioned yaw detection masses Y1, Y2, Y1', Y2' have a substantially rectangular frame configuration along a first horizontal axis x, defining inside a window 31 for a movable yaw detection electrode 32, which is fixed relative to the frame and is connected to a corresponding fixed detection electrode or yaw stator electrode S also arranged in the window 31. Y 1. SY 2. S Y 1', S y 2' (not shown here for reasons of clarity) alternating.

[0102] The identical yaw proof masses Y1, Y2, Y1', Y2' are further elastically coupled to a yaw anchor 35, which is arranged centrally to the corresponding frame. Furthermore, the yaw proof masses Y1, Y2, Y1', Y2' in each pair are elastically coupled together by an elastic coupling element 36, which has a linear extension along the first horizontal axis x and is arranged between the corresponding frames.

[0103] It is therefore emphasized that in the described solution, for each detection axis, the above-mentioned first group of stator electrodes (S1, S1') are electrically connected together to form a positive detection electrode for a differential detection scheme, and the above-mentioned second group of stator electrodes (S2, S2') are electrically connected together to form a negative detection electrode for the same differential detection scheme, and the electrodes in the first group are arranged with respect to the electrodes in the second group in a centrally symmetrical (in the case of the pitch detection axis and the roll detection axis) or axially symmetrical (in the case of the yaw detection axis, the axis of symmetry coincides with the above-mentioned second horizontal axis y).

[0104] The operation of the detection structure 10 for detecting the above-mentioned roll angular velocity Ω is now described. R , pitch angular velocity Ω P and yaw angular velocity Ω Y .

[0105] like Figure 4 As schematically illustrated in FIG. 1 , the drive movement envisages that the drive masses D1, D2, D1′, D2′ are driven (by appropriate biasing of the movable drive electrode 17 and the corresponding fixed drive electrodes) so as to perform a translational movement (in antiphase for each pair) along the second horizontal axis y. Furthermore, the movements of the drive masses D1, D2′ and D2, D1′, which are mutually symmetrical with respect to the first horizontal axis x, are also in antiphase.

[0106] As above Figure 4 As indicated by the arrows in , due to the elastic coupling, the above-mentioned movement of the driving masses D1, D2, D1', D2' causes the roll detection masses R1, R2, R1', R2' in the two pairs (the masses in each pair move fixedly relative to each other) to rotate in opposite phases in the horizontal plane xy around an axis parallel to the vertical axis z and passing through the center of the corresponding roll anchor 14.

[0107] Furthermore, the pitch proof masses P1, P2, P1', P2' are driven (or dragged) by the drive masses D1, D2, D1', D2' into corresponding anti-phase translational movements along the second horizontal axis y. This movement in turn involves a rotation in the horizontal plane xy around the respective central anchor 27 of the elastic lever element 26 of the elastic coupling structure 25, which couples together the pitch proof masses P1 and P2, P1' and P2' in the same pair (the remaining elastic coupling structure 25 remains stationary). The yaw proof masses Y1, Y2, Y1', Y2' are further fixedly coupled to the respective pitch proof masses P1, P2, P1', P2' during the respective drive movements.

[0108] The above-described drive movement therefore takes place entirely in the horizontal plane xy and does not involve other elements of the detection structure 10 .

[0109] like Figure 5A As schematically illustrated in (for a given operating moment), in the presence of a roll angular velocity Ω about the second horizontal axis y R In this case, the movement of the detection structure 10 envisages that the set of rolling detection masses R1, R2, R1', R2' in each pair rotates in anti-phase around a rotation axis defined by the corresponding elastic anchoring element 15 and the corresponding elastic drive element 21 parallel to the first horizontal axis x.

[0110] Basically, on the other hand Figure 5A As schematically represented in FIG. 1 , due to the generated Coriolis force, the roll proof mass R1 , R2 , R1 ′, R2 ′ in each pair performs a movement along the vertical axis z, moving away from or approaching the corresponding roll stator electrode S R 1. S R 2. S R 1', S R 2' (not shown here), resulting in an overall capacitance change, which can be detected by a differential detection scheme.

[0111] In addition to the above drive and roll detection movement (due to the Coriolis force Co), Figure 5B The linear acceleration V of the disturbance is schematically shown (for a given operating moment) L (along the vertical axis z) and the angular acceleration V of the disturbance A (acting around the first horizontal axis x, thereby causing the rotational movement of the roll detection masses R1, R2, R1', R2' around the first horizontal axis x).

[0112] It is obvious how a linear acceleration causes all the roll proof masses R1, R2, R1', R2' to move in phase and thus be suppressed by the differential detection scheme. AThis causes the roll detection masses R1 and R2, R1' and R2' in each pair to move in phase (e.g., at the operational moment shown, both the roll detection masses R1, R2 in the first pair move away from the substrate 11, and both the roll detection masses R1', R2' in the second pair move toward the substrate 11 to the corresponding roll stator electrodes).

[0113] Therefore, it is obvious that, also in this case, the differential detection scheme is able to eliminate the influence caused by the disturbed angular acceleration and thus is consistent with the roll angular velocity Ω to be detected. R Different, the disturbed angular acceleration will not affect the output signal S out .

[0114] like Fig. 6A As schematically illustrated in (for a given operating moment), in the presence of a pitch angular velocity Ω about the first horizontal axis x P In this case, the movement of the detection structure 10 envisages anti-phase displacements of the pitch detection masses P1, P2, P1', P2' in each pair along the vertical axis z (in addition, anti-phase movements of the pitch detection masses P1, P2', P2, P1' that are symmetrical with respect to the first horizontal axis x along the same vertical axis z are envisaged).

[0115] This movement of the pitch proof masses P1, P2, P1', P2' along the vertical axis z, outside the horizontal plane xy (as described above) is allowed by the rotation of the elastic lever elements 26 of all the elastic coupling structures 25 about the central anchor 27. Fig. 6A Schematically illustrated in FIG.

[0116] Basically, as a result of the Coriolis force, the pitch proof masses P1, P2, P1', P2' perform a movement along the vertical axis z, moving away from / approaching the corresponding pitch stator electrode S P 1. S P 2. S P 1', S P 2', thereby as a whole causing a capacitance change that can be detected by the differential detection scheme described above.

[0117] like Figure 6B As schematically illustrated in (about a given operating moment), also in this detection mode, the linear acceleration V L This results in an in-phase movement of all pitch proof masses P1, P2, P1', P2', which is suppressed by the differential detection scheme. Similarly, the angular acceleration V of the disturbance acting around the first horizontal axis x AThe pitch proof masses P1 and P2, P1' and P2' in each pair are caused to move in phase (eg both pitch proof masses P1, P2 in the first pair move away from the substrate 11, while both pitch proof masses P1', P2' in the second pair move closer to the substrate 11).

[0118] It is therefore evident that, also in this case, the differential detection scheme is able to eliminate the effects associated with both the linear and angular vibrations of the disturbance.

[0119] like Fig. 7A As schematically illustrated in FIG. , in the presence of a yaw angular velocity Ω about the vertical axis z Y In the case of , the detection movement of the detection structure 10 envisages anti-phase displacements of the pitch proof masses P1, P2, P1', P2' of each pair along the first horizontal axis x, and therefore (due to the elastic coupling) anti-phase movements of the yaw proof masses Y1, Y2, Y1', Y2' of each pair around the rotation of the respective yaw anchor 35 in the horizontal plane xy. In particular, the yaw proof masses Y1, Y2, Y1', Y2' are pulled (or dragged) along the pitch proof masses P1, P2, P1', P2' by the respective yaw elastic coupling elements 29 moving along the first horizontal axis x.

[0120] The described movement also involves a rotation in the horizontal plane xy about the respective central anchor 27 of the elastic lever element 26 of the elastic coupling structure 25 coupling together the pitch proof masses P1 , P2 ′, P2 , P1 ′ which are mutually symmetrical with respect to the first horizontal axis x.

[0121] Thus, a movement of the yaw movable electrode 32 (not shown here) relative to the alternating yaw stator electrode along the second horizontal axis y occurs and a resulting capacitance change which can be detected by a differential scheme.

[0122] like Figure 7B In this detection mode, the linear acceleration V L This results in the in-phase movement of all yaw detection masses Y1, Y2, Y1', Y2', which produces essentially no capacitance change between the yaw detection electrodes. In addition, the perturbed angular acceleration V A (acting in this case in the horizontal plane xy about the vertical axis z at the center of the detection structure 10) results in an in-phase movement of the yaw detection masses Y1 and Y2, Y1' and Y2' in each pair, resulting in the movable yaw detection electrodes S alternating with each other. Y 1 and S Y 2 and fixed yaw detection electrode S Y 1' and S Y2' (illustrated here schematically and with different names for the positive electrode '+' and the negative electrode '-' for a differential detection scheme).

[0123] It is therefore evident that, also in this case, the differential detection scheme is able to eliminate the effects associated both with the disturbing linear acceleration and with the disturbing angular vibration.

[0124] Reference Figure 8 , a second embodiment of the detection structure, herein designated by 10', will now be described.

[0125] As above Figure 8 , the main difference compared to the first embodiment is that there are no different yaw proof masses. In fact, in this embodiment, the pitch proof masses P1, P2, P1', P2' also define a yaw proof mass internally and contain a frame 31' therein, which frame 31' internally defines a window 31 for a movable yaw detection electrode 32, which alternates with a corresponding fixed yaw detection electrode (not shown) and is designed to detect the yaw angular velocity Ω around the vertical axis z. Y .

[0126] In this embodiment, the driving masses D1, D2, D1', D2' are arranged on the outside relative to the above-mentioned pitch detection masses P1, P2, P1', P2' in the horizontal plane xy, and the pitch detection masses P1, P2, P1', P2' are therefore arranged between the corresponding driving masses D1, D2, D1', D2' and the corresponding roll detection masses R1, R2, R1', R2'.

[0127] Also in this case, each pitch proof mass P1 , P2 , P1 ′, P2 ′ is coupled to a respective driving mass D1 , D2 , D1 ′, D2 ′ via a respective driving elastic coupling element 22 having an extension along the second horizontal axis y.

[0128] In this case, the driving masses D1 and D2 , D1 ′ and D2 ′ in each pair are elastically coupled together by respective elastic coupling structures designated by 37 , which define elastic central fulcrum lever elements articulated to the substrate 11 by a central anchor 38 .

[0129] In this second embodiment, the roll detection masses R1 and R2, R1' and R2' in each pair (fixed relative to each other as in the first embodiment) are surrounded by a corresponding rigid ring structure 40 in the horizontal plane xy; an elastic central element 42 of torsion type with a rectangular frame construction (arranged in a position corresponding to the first horizontal axis x) elastically couples the ring structures 40 associated with the two pairs of roll detection masses R1, R2, R1', R2'.

[0130] In this case, the pitch detection masses P1 and P2, P1' and P2' in each pair are coupled together through the above-mentioned annular structure 40; specifically, the pitch detection masses P1 and P2, P1' and P2' in each pair are coupled to the corresponding annular structure 40 at the central part of the same annular structure 40 (aligned with the elastic anchoring element 15 along the first horizontal axis x) through the corresponding elastic elements 41 of the folding type.

[0131] Furthermore, the pitch detection masses P1 , P2 ′, P2 , P1 ′ which are symmetrical to each other with respect to the first horizontal axis x are again coupled via a central fulcrum elastic coupling structure 25 , which is hinged to the substrate 11 via a corresponding central anchor 27 .

[0132] like Fig. 9 As schematically illustrated in FIG. 1 , the driven movement of the detection structure 10 ′ is substantially identical to the movement described with reference to the first embodiment.

[0133] The drive masses D1, D2, D1', D2' are in fact driven (by appropriate biasing of movable drive electrodes and alternating fixed drive electrodes, not shown) so as to perform an anti-phase translational movement along a second horizontal axis y, which carries the pitch detection masses P1, P2, P1', P2' with a similar translational movement and also involves the rotation of the elastic lever elements of the elastic coupling structure 37, which couples the drive masses D1, D2, D1', D2' in each pair together, around the corresponding central anchor 38.

[0134] In addition, the movement of the driving masses D1, D2' and D2, D1' (symmetrical with respect to the first horizontal axis x) causes, due to elastic coupling, the roll detection masses R1, R2, R1', R2' in the two pairs to rotate in opposite phases around an axis in the horizontal plane xy, which is parallel to the vertical axis z and passes through the center of the corresponding roll anchor 14.

[0135] Again in a manner similar to that described for the first embodiment, and as Fig.10 As schematically illustrated in FIG. 1 , in the presence of a roll angular velocity Ω about the second horizontal axis y RIn this case, the movement of the detection structure 10 ′ envisages an anti-phase rotation of the rolling proof masses R1 , R2 , R1 ′, R2 ′ about an axis of rotation defined by the respective elastic elements and parallel to the first horizontal axis x.

[0136] like Fig.11 As shown in the figure, there is a pitch angular velocity Ω around the first horizontal axis x P In this case, the movement of the detection structure 10' also envisions in this embodiment the anti-phase displacement of the pitch detection masses P1, P2, P1', P2' in each pair along the vertical axis z (further envisioning the anti-phase movement of the pitch detection masses P1, P2', P2, P1' that are symmetrical with respect to the first horizontal axis x).

[0137] As described for the first embodiment, this movement of the pitch proof masses P1, P2, P1', P2' is achieved by the rotation of the corresponding elastic lever elements of the elastic coupling structure 25, which couples the pitch proof masses P1, P2', P2, P1' symmetrical to each other with respect to the first horizontal axis x, this movement taking place outside the horizontal plane xy (along the vertical axis z) around the corresponding central anchor 27. In this second embodiment, the coupling between the pitch proof masses P1, P2', P2, P1' is further provided by the corresponding annular structure 40, which rotates outside the horizontal plane xy around the second horizontal axis y.

[0138] like Fig. 12A As shown in the figure, in the presence of a yaw angular velocity Ω around the vertical axis z Y In this case, the movement of the detection structure 10' envisages a displacement of the pitch detection masses P1, P2, P1', P2' in each pair by anti-phase translation along the first horizontal axis x, and therefore a corresponding movement of the movable and fixed yaw detection electrodes within the frame 31 along the first horizontal axis x, which are fixed relative to the pitch detection masses P1, P2, P1', P2', thereby causing a change in the capacitive coupling that can be detected by the differential detection scheme.

[0139] In a manner evident from what has already been described, completely analogous considerations to those mentioned for the first embodiment also apply to this second embodiment regarding the suppression of disturbing linear and angular accelerations (such considerations will therefore not generally be repeated).

[0140] Reference Fig. 12B For the sake of completeness only, a schematic representation is provided for the above-mentioned yaw movement of the detection structure 10 ′ with regard to the parts that are different from those described for the first embodiment.

[0141] In this detection mode, the linear acceleration VL The in-phase movement of all pitch detection masses P1, P2, P1', P2' along the first horizontal axis x and the resulting uniform movement of the movable yaw detection electrodes, thus involving relative to the fixed yaw detection electrodes S Y 1 and S Y 2. S Y 1' and S Y 2', which is suppressed by the differential detection scheme (again the electrodes are illustrated schematically, and different names are used for the positive electrode '+' and the negative electrode '-' for the differential detection scheme).

[0142] Likewise, the angular acceleration of the disturbance (in this case acting in the horizontal plane xy about the centre of the detection structure 10' and about the vertical axis z) causes in-phase movements of the pitch detection masses P1, P2, P1', P2' in each pair (the movements of the pairs being in mutually opposite directions) and hence corresponding relative retreat or approach movements between the movable and fixed yaw detection electrodes alternating with each other.

[0143] It is therefore evident that, also in this case, the differential detection scheme is able to eliminate the effects associated with both the linear and angular acceleration of the disturbance.

[0144] The advantages of the proposed solution emerge clearly from the foregoing description.

[0145] In any case, it is emphasized that the solution described allows to obtain an improved vibration suppression (in particular angular vibrations in addition to linear vibrations) compared to known solutions, without involving any significant increase in the area occupied by the detection structure and without involving any increase in electrical consumption.

[0146] Furthermore, it is emphasized that the described second embodiment has the advantage of having a simpler architecture (absence of four additional yaw proof masses), however, has the disadvantage of possible parasitic modes with respect to yaw movement.

[0147] Finally, it is evident that modifications and variations can be made to what has been described and illustrated, without departing from the scope of the present invention, as defined in the accompanying claims.

[0148] In particular, it is emphasized that the positions of the various proof masses in the detection structure and the configurations of the associated elastic couplings and anchors may differ from what is illustrated in detail herein for the first and second embodiments.

[0149] For example, the roll proof masses R1 , R2 , R1 ′, R2 ′ in each pair may not be fixedly coupled together, but rather different and coupled together in a suitable manner.

[0150] Further, it is pointed out that the described solution can also be advantageously applied to the detection structure of a dual-axis or single-axis gyroscope, thereby maintaining the advantageous feature of improved insensitivity to vibration disturbances of a linear or angular nature.

Claims

1. A three-axis micro-electromechanical gyroscope, characterized in that: include: a die of semiconductor material, the die comprising a substrate; a detection structure suspended above the substrate; wherein the detection structure has a main extension in a horizontal plane and is symmetrical with respect to a first horizontal axis and a second horizontal axis, wherein the first horizontal axis and the second horizontal axis define the horizontal plane; The detection structure comprises: a first roll proof mass and a second roll proof mass, arranged symmetrically on opposite sides with respect to the first horizontal axis; a first pair of drive masses and a second pair of drive masses, wherein the first pair of drive masses are arranged lateral to and outboard of the first roll detection mass, and the second pair of drive masses are arranged lateral to and outboard of the second roll detection mass, and the first pair of drive masses and the second pair of drive masses are symmetrical in the horizontal plane and relative to the second horizontal axis; a first pair of pitch proof-masses and a second pair of pitch proof-masses, wherein the first pair of pitch proof-masses are arranged on a lateral side and outside of the first roll proof-masses, and the second pair of pitch proof-masses are arranged on a lateral side and outside of the second roll proof-masses, and the first pair of pitch proof-masses and the second pair of pitch proof-masses are symmetrical in the horizontal plane and relative to the second horizontal axis; wherein each pitch detection mass is coupled to a corresponding driving mass through a corresponding driving elastic coupling element; A first pair of yaw detection elements and a second pair of yaw detection elements are coupled to the first pair of pitch proof masses and the second pair of pitch proof masses, respectively; wherein the drive masses are configured to be driven to perform translational movements along the second horizontal axis, for each pair of drive masses, in opposite directions, the movements of the drive masses being symmetrical to each other with respect to the first horizontal axis also in opposite directions; wherein the movement of the drive mass is designed to cause anti-phase rotation of the first roll proof mass and the second roll proof mass in the horizontal plane and cause corresponding translational movement in opposite directions along the second horizontal axis of the pitch proof mass pulled by the drive mass; and Wherein, during the driving movement, the yaw detection element is rigidly coupled to the corresponding pitch detection mass block.

2. The three-axis micro-electromechanical gyroscope according to claim 1, characterized in that: Respective roll stator electrodes are disposed beneath the first and second roll proof masses, capacitively coupled to respective roll proof masses, and positioned on the substrate to provide a differential detection scheme; wherein a respective pitch stator electrode is arranged below a pitch proof mass in each pair of pitch proof masses, capacitively coupled to the respective pitch proof mass and positioned on the substrate to provide a respective differential detection scheme; and wherein the yaw detection element has a basic frame construction defining windows internally for movable yaw detection electrodes, the movable yaw detection electrodes alternating with corresponding fixed yaw detection electrodes and capacitively coupled to provide a respective differential detection scheme; Wherein in the differential detection scheme, the angular velocity around the corresponding detection axis causes a detectable change in the detection capacitance caused by the capacitive coupling to determine the change in the output signal associated with the differential detection scheme, and linear vibration or angular vibration does not substantially cause a change in the detection capacitance.

3. The three-axis micro-electromechanical gyroscope according to claim 2, characterized in that: In the presence of said linear or angular vibration, said first roll proof mass and said second roll proof mass are configured to perform an in-phase rotational movement in said horizontal plane; and further said pitch proof mass is configured to perform a corresponding in-phase movement along said second horizontal axis.

4. The three-axis micro-electromechanical gyroscope according to claim 1, characterized in that: Each of the first roll detection mass and the second roll detection mass centrally defines a window, in which a corresponding roll anchor fixedly connected to the substrate is arranged, and a torsion-type elastic anchoring element connects each of the first roll detection mass and the second roll detection mass to the corresponding anchor; wherein, in the presence of a roll angular velocity around the second horizontal axis, the movement of the detection structure is configured to implement an anti-phase rotation of the first roll detection mass and the second roll detection mass outside the horizontal plane around a rotation axis defined by the corresponding elastic anchoring element.

5. The three-axis micro-electromechanical gyroscope according to claim 1, characterized in that: Each pitch detection mass block in the first pair of pitch detection mass blocks is coupled to a corresponding pitch detection mass block in the second pair of pitch detection mass blocks arranged symmetrically relative to the first horizontal axis through a corresponding elastic coupling structure, and the corresponding elastic coupling structure extends centrally and intersects with the first horizontal axis; each elastic coupling structure defines an elastic lever element of a center fulcrum type, and the elastic lever element of the center fulcrum type is hinged to the substrate through a central anchor.

6. The three-axis micro-electromechanical gyroscope according to claim 5, characterized in that: In the presence of an angular pitch velocity about the first horizontal axis, the movement of the detection structure is configured to implement anti-phase displacements of the pitch proof masses in each pair of pitch proof masses along a vertical axis, the vertical axis being orthogonal to the horizontal plane, and further to implement anti-phase displacements of each pitch proof mass in the first pair of pitch proof masses and the corresponding pitch proof mass in the second pair of pitch proof masses along the vertical axis due to the rotation of the elastic lever element of the elastic coupling structure about the central anchor outside the horizontal plane.

7. The three-axis micro-electromechanical gyroscope according to claim 1, characterized in that: The pitch detection mass block is arranged outside the roll detection mass block in the horizontal plane and is coupled together by corresponding elastic coupling structures to define a rectangular frame as a whole in the horizontal plane. The corresponding elastic coupling structure extends centrally and intersects the first horizontal axis or the second horizontal axis. The drive mass block and the roll detection mass block are enclosed in the rectangular frame. Each elastic coupling structure defines an elastic lever element of a central fulcrum type, and the elastic lever element of the central fulcrum type is hinged to the substrate through a central anchor.

8. The three-axis micro-electromechanical gyroscope according to claim 7, characterized in that: each of the first pair of drive masses is coupled to a corresponding drive mass of the second pair of drive masses arranged symmetrically with respect to the first horizontal axis via a corresponding elastic coupling element, the corresponding elastic coupling element extending along the second horizontal axis; and Each of the driving masses in the first pair of driving masses and the second pair of driving masses is centrally coupled to the first roll detection mass and the second roll detection mass through a corresponding elastic drive element.

9. The three-axis micro-electromechanical gyroscope according to claim 8, characterized in that: The detection structure further comprises a first pair of yaw detection masses and a second pair of yaw detection masses, wherein the first pair of yaw detection masses and the second pair of yaw detection masses are arranged outside the first pair of pitch detection masses and the second pair of pitch detection masses, respectively, in the horizontal plane, wherein each yaw detection mass is elastically coupled to a corresponding pitch detection mass by a corresponding yaw elastic coupling element; wherein the yaw detection masses have a basic frame-like construction, wherein the basic frame-like construction internally defines windows for movable yaw detection electrodes, and the movable yaw detection electrodes are alternated with corresponding fixed yaw detection electrodes.

10. The three-axis micro-electromechanical gyroscope according to claim 9, characterized in that: The first roll detection mass and the second roll detection mass are elastically coupled together by an elastic coupling element arranged at the first horizontal axis.

11. The three-axis micro-electromechanical gyroscope according to claim 1, characterized in that: The drive mass is arranged outside the pitch detection mass in the horizontal plane; and the drive mass in each pair of drive masses is elastically coupled by a corresponding elastic coupling structure, which defines an elastic lever element with a central fulcrum, and the central fulcrum is hinged to the substrate by a central anchor.

12. The three-axis micro-electromechanical gyroscope according to claim 11, characterized in that: The pitch proof mass contains a frame therein, the frame internally defining windows for movable yaw detection electrodes, the movable yaw detection electrodes being fixed relative to the frame and alternating with corresponding fixed yaw detection electrodes, the movable yaw detection electrodes being designed to detect yaw angular velocity about a vertical axis, the vertical axis being orthogonal to the horizontal plane.

13. The three-axis micro-electromechanical gyroscope according to claim 12, characterized in that: Each of the first roll detection mass block and the second roll detection mass block is surrounded by a corresponding annular structure in the horizontal plane, and the corresponding annular structure further couples the pitch detection mass blocks of the first pair of pitch detection mass blocks and the second pair of pitch detection mass blocks together, respectively; and a torsion-type elastic central element with a rectangular frame structure is arranged at the first horizontal axis and is configured to elastically couple the elastic annular structures associated with the first roll detection mass block and the second roll detection mass block.

14. The three-axis micro-electromechanical gyroscope according to claim 13, characterized in that: The pitch proof masses of the first pair of pitch proof masses and the second pair of pitch proof masses are coupled to the respective annular structures via respective elastic elements at central portions of the respective annular structures; Thus, the pitch proof mass of the first and second pairs of pitch proof masses is inserted between a corresponding drive mass of the first and second pairs of drive masses and a corresponding one of the first and second roll proof masses.

15. The three-axis micro-electromechanical gyroscope according to claim 1, characterized in that: The first horizontal axis coincides with the pitch detection axis of the detection structure, and the pitch angular velocity will be detected around the pitch detection axis; the second horizontal axis coincides with the roll detection axis of the detection structure, and the roll angular velocity will be detected around the roll detection axis; and the vertical axis orthogonal to the horizontal plane coincides with the yaw detection axis, and the yaw angular velocity will be detected around the yaw detection axis.

16. A micro-electromechanical gyroscope, characterized in that: include: a die of semiconductor material, the die comprising a substrate; and a detection structure suspended above the substrate; The detection structure has a main extension in a horizontal plane, is symmetrical with respect to a central symmetry axis, and comprises for each detection axis of the micro-electromechanical gyroscope: a first pair of proof masses arranged on a first side of the central axis of symmetry; and a second pair of proof masses arranged in the horizontal plane on a second side of the central axis of symmetry, the second side being opposite to the first side; wherein the proof masses in each of the first pair of proof masses and the second pair of proof masses are capacitively coupled to respective stator electrodes according to a differential detection scheme; and The stator electrodes are arranged symmetrically with respect to each other on opposite sides of the central symmetry axis.

17. The micro-electromechanical gyroscope according to claim 16, characterized in that: the proof mass being configured such that angular velocity about a respective one of the sense axes causes a detectable change in sense capacitance to determine a change in an output signal associated with the differential detection scheme, the detectable change in sense capacitance resulting from the capacitive coupling with the stator electrodes; And linear vibration or angular vibration acting around the central symmetry axis will not substantially cause any change in the detection capacitance.

18. The micro-electromechanical gyroscope according to claim 17, characterized in that: The proof masses in each pair of proof masses are configured to perform: anti-phase movement due to Coriolis forces associated with angular velocity about the respective detection axis; and in-phase movement due to linear or angular vibrations acting about the central symmetry axis.

19. The micro-electromechanical gyroscope according to claim 16, characterized in that: A first group of stator electrodes are electrically connected together to form a positive detection electrode for the differential detection scheme, and a second group of stator electrodes are electrically connected together to form a negative detection electrode for the differential detection scheme; wherein the stator electrodes in the first group of stator electrodes are arranged in a centrally symmetrical or axially symmetrical manner relative to the stator electrodes in the second group of stator electrodes.

20. The micro-electromechanical system gyroscope according to claim 16, characterized in that: The detection structure also includes a first pair of driving masses and a second pair of driving masses, wherein the first pair of driving masses and the second pair of driving masses are arranged on opposite sides relative to the central symmetry axis, and are respectively arranged beside and outside the first pair of detection masses and the second pair of detection masses; wherein each driving mass in the first pair of driving masses is coupled to a corresponding driving mass in the second pair of driving masses symmetrically arranged relative to the central symmetry axis through a corresponding elastic coupling element of a folding type, and the corresponding elastic coupling element of the folding type extends along an axis perpendicular to the central symmetry axis; and wherein each driving mass in the driving masses is centrally coupled to a corresponding one of the detection masses through a corresponding elastic driving element.

21. The micro-electromechanical system gyroscope according to claim 16, characterized in that: The central symmetry axis is a first horizontal axis, which coincides with a pitch detection axis of the detection structure, and the pitch angular velocity is detected around the pitch detection axis; the detection structure is further symmetrical with respect to a second horizontal axis, which together with the first horizontal axis forms the horizontal plane, and which coincides with a roll detection axis of the detection structure, and the roll angular velocity is detected around the roll detection axis; the detection structure further has an extension portion along a vertical axis that is smaller than the main extension portion, the vertical axis is orthogonal to the horizontal plane and coincides with a yaw detection axis, and the yaw angular velocity is detected around the yaw detection axis.

22. The micro-electromechanical gyroscope according to claim 21, characterized in that: The first pair of detection masses and the second pair of detection masses include a first pair of roll detection masses and a second pair of roll detection masses, the first pair of roll detection masses and the second pair of roll detection masses being symmetrically arranged on opposite sides with respect to the first horizontal axis; wherein respective roll stator electrodes arranged below the roll detection masses in the first pair of roll detection masses and the second pair of roll detection masses are capacitively coupled to the respective roll detection masses and positioned on the substrate to provide the differential detection scheme; and wherein the roll detection masses in each pair of the first pair of roll detection masses and the second pair of roll detection masses are fixedly coupled together to form a single body and centrally define a window in which respective roll anchors fixedly connected to the substrate are arranged, and wherein torsion-type elastic anchoring elements connect the roll detection masses in each pair of the first pair of roll detection masses and the second pair of roll detection masses to the respective anchors.

23. The micro-electromechanical gyroscope according to claim 22, characterized in that: It also includes a first pair of driving mass blocks and a second pair of driving mass blocks, wherein the first pair of driving mass blocks and the second pair of driving mass blocks are arranged on opposite sides relative to the first horizontal axis, beside and outside the roll detection mass blocks in the first pair of roll detection mass blocks and the second pair of roll detection mass blocks, respectively; wherein each driving mass block in the first pair of driving mass blocks is coupled to a corresponding driving mass block in the second pair of driving mass blocks arranged symmetrically relative to the first horizontal axis x through a corresponding elastic coupling element of a folding type, and the corresponding elastic coupling element of the folding type extends along the second horizontal axis; and wherein each driving mass block in the driving mass blocks is centrally coupled to a corresponding one of the roll detection mass blocks through a corresponding elastic driving element.

24. The micro-electromechanical gyroscope according to claim 23, characterized in that: Also comprising a first pair of pitch detection masses and a second pair of pitch detection masses, wherein the first pair of pitch detection masses and the second pair of pitch detection masses are arranged beside and outside the roll detection masses in the first pair of roll detection masses and the second pair of roll detection masses, respectively, on opposite sides relative to the first horizontal axis; wherein corresponding pitch stator electrodes are arranged below the pitch detection masses in each pair of the first pair of pitch detection masses and the second pair of pitch detection masses, and are capacitively coupled to the corresponding pitch detection masses and positioned on the substrate to provide a corresponding differential detection scheme; Each pitch detection mass is coupled to a corresponding driving mass through a corresponding elastic coupling driving element.

25. The micro-electromechanical gyroscope according to claim 24, characterized in that: The drive mass is configured to be driven to perform anti-phase translational movement along the second horizontal axis for each pair of drive masses, and the mutually symmetrical movements of the drive masses relative to the first horizontal axis are anti-phase; wherein the movement of the drive mass is designed to cause anti-phase rotation of the roll detection masses of the first pair of roll detection masses and the second pair of roll detection masses in the horizontal plane around an axis parallel to the vertical axis and passing through the center of the corresponding roll anchor; and wherein the pitch detection mass is carried by the drive mass to perform corresponding anti-phase translational movement along the second horizontal axis.

26. The micro-electromechanical gyroscope according to claim 24, characterized in that: The pitch detection mass block is arranged outside the driving mass block in the horizontal plane and is coupled together by corresponding elastic coupling structures to define a rectangular frame as a whole in the horizontal plane. The corresponding elastic coupling structure extends centrally and intersects the first horizontal axis or the second horizontal axis. The driving mass block and the roll detection mass block are enclosed in the rectangular frame. Each elastic coupling structure defines an elastic lever element of a central fulcrum type, and the elastic lever element of the central fulcrum type is hinged to the substrate through a central anchor.

27. The micro-electromechanical gyroscope according to claim 26, characterized in that: It also includes a first pair of yaw detection masses and a second pair of yaw detection masses, wherein the first pair of yaw detection masses and the second pair of yaw detection masses are respectively arranged on the outside of the pitch detection masses in the first pair of pitch detection masses and the second pair of pitch detection masses on opposite sides relative to the first horizontal axis; wherein each yaw detection mass is elastically coupled to the corresponding pitch detection mass by a corresponding yaw elastic coupling element; wherein, during the driving movement, the yaw detection mass is fixedly coupled to the corresponding pitch detection mass.

28. The micro-electromechanical gyroscope according to claim 27, characterized in that: The yaw proof mass has a substantially frame-like configuration defining internally windows for movable yaw detection electrodes alternating with corresponding fixed yaw detection electrodes.

29. The micro-electromechanical gyroscope according to claim 26, characterized in that: The pitch proof mass comprises a frame therein, the frame internally defining windows for movable yaw detection electrodes, the movable yaw detection electrodes being fixed relative to the frame and alternating with corresponding fixed yaw detection electrodes, the movable yaw detection electrodes being designed to detect the yaw angular velocity about the vertical axis.

30. The gyroscope according to claim 29, characterized in that The drive mass is arranged outside the pitch detection mass in the horizontal plane; and wherein the drive masses in each of the first pair of drive masses and the second pair of drive masses are elastically coupled by corresponding elastic coupling structures, and the corresponding elastic coupling structures define an elastic lever element with a central fulcrum, and the central fulcrum is hinged to the substrate by a central anchor.

31. The micro-electromechanical gyroscope according to claim 30, characterized in that: The roll detection masses in each pair of the first pair of roll detection masses and the second pair of roll detection masses are surrounded by corresponding annular structures in the horizontal plane, and the corresponding annular structures further couple the pitch detection masses in each pair of the first pair of pitch detection masses and the second pair of pitch detection masses together; and wherein an elastic central element of a torsion type having a rectangular frame configuration is arranged at the first horizontal axis and is configured to elastically couple the elastic annular structures associated with the first pair of roll detection masses and the second pair of roll detection masses.

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