CN111174772B - Triaxial MEMS gyroscope - Google Patents

Abstract

The invention discloses a triaxial MEMS gyroscope, which comprises a substrate; a first detection unit for detecting an angular velocity around the X direction; the second detection part and the third detection part are symmetrically arranged at two sides of the first detection part, are respectively connected with the first detection part, and are arranged to provide driving forces with opposite directions and can be used for detecting angular speeds around the Y direction and around the Z direction; wherein the X direction is perpendicular to the Y direction, and the Z direction is perpendicular to the X direction and the Y direction; the suspension device is suspended on the substrate through the anchor point group, is arranged outside the first detection part, the second detection part and the third detection part and is connected with the second detection part and the third detection part; the suspension means is arranged such that the second and third detection portions remain parallel or substantially parallel to the substrate when movement in the Z direction occurs. The triaxial MEMS gyroscope has compact structure and low cost, can weaken or eliminate double frequency, and has strong output signal.

Description

Triaxial MEMS gyroscope

Technical Field

The invention relates to the field of MEMS sensors, in particular to an MEMS gyroscope.

Background

MEMS (Micro-Electro-Mechanical-Systems) technology is developed from conventional semiconductor processing technology, and the fabrication of Micro-Mechanical structures and Systems is implemented by using semiconductor processing methods to implement specific functions, where the smallest typical dimension is generally in the micrometer scale. The application of the MEMS technology enables related devices to be easy to realize mass production, the cost is greatly reduced, market application is popularized, meanwhile, the power consumption is reduced, the reliability is improved, and further the development of the MEMS technology is promoted. Unlike conventional semiconductor processing, MEMS processing may use deep silicon etching, e.g., etching depths of 100-300um, requiring precise control of verticality. Many MEMS devices also require vacuum bonding techniques to improve Q and protect internal structures such as MEMS gyroscopes and MEMS oscillators. MEMS materials are also diverse and may be contaminated with metal ions or particles, with some of the process steps requiring isolation separately. Because of the movable structure, the stress problem is the biggest problem of the MEMS device, and the prevention and the solution of the stress problem penetrate through the whole flow of the design, the processing, the sealing and the application of the MEMS device.

The MEMS gyroscope has very wide application, including inertial navigation, optical anti-shake, panoramic photography, vehicle body stabilization, safety and the like. A MEMS gyroscope is generally used to detect angular velocity, and belongs to an angular velocity sensor, and the core of the MEMS gyroscope is the coriolis force principle, which converts an input angular velocity into a displacement of a specific sensing structure, and detects the displacement to determine the magnitude of the angular velocity. The MEMS gyroscope belongs to an active device, a system carries out simple harmonic vibration at a resonance point after being electrified, when angular velocity is input in the direction perpendicular to the moving direction of a mass block, a Golgi force is generated in the direction perpendicular to the moving direction of the mass block and the direction of the input angular velocity, and the corresponding representation quantity of the angular velocity can be obtained through a detection structure and a peripheral processing circuit. The most widely used driving modes at present are static electricity and piezoelectricity, and the detection modes are capacitance and piezoelectricity. The consumer market is the maximum application market of the MEMS gyroscope, has severe requirements on product price and performance, and is constantly striving to develop MEMS gyroscope products with low cost, high performance and high reliability in the field, in particular to a three-axis MEMS gyroscope, and the MEMS gyroscope is further integrated with a three-axis accelerometer to form a six-axis IMU.

Disclosure of Invention

In view of market demands and some technical commonalities, the invention aims to provide a triaxial MEMS gyroscope which has compact structure, low cost, reduced or eliminated double frequency and strong output signal. The present invention may also address only one or more of the above problems.

To achieve the above object, the present invention provides a triaxial MEMS gyroscope. In one embodiment, the tri-axial MEMS gyroscope comprises

The substrate is provided with a plurality of holes,

a first detection unit for detecting an angular velocity around the X direction;

the second detection part and the third detection part are symmetrically arranged at two sides of the first detection part, are respectively connected with the first detection part, and are arranged to provide driving forces with opposite directions and can be used for detecting angular speeds around the Y direction and around the Z direction; wherein the X direction is perpendicular to the Y direction, and the Z direction is perpendicular to the X direction and the Y direction; and

the suspension device is suspended on the substrate through the anchor point group, is arranged outside the first detection part, the second detection part and the third detection part, and is connected with the second detection part and the third detection part, so that the second detection part and the third detection part are suspended relative to the substrate; the suspension means is arranged such that the second and third detection portions remain parallel or substantially parallel to the substrate when movement in the Z direction occurs. The variability of the setting position of the Y-direction detection capacitor bank is improved so that the capacitance value change at any one of the second detection portion and the third detection portion is the same or substantially the same, which also improves the accuracy of detection to some extent.

Further, the suspension device comprises a first arm and a second arm which are symmetrically arranged;

the first arm comprises a first arm first section, a first arm second section and a first arm third section, wherein the first arm first section and the first arm second section are connected through a first spring, and the first arm second section and the first arm third section are connected through a second spring;

the second arm comprises a second arm first section, a second arm second section and a second arm third section, wherein the second arm first section and the second arm second section are connected through a third spring, and the second arm second section and the second arm third section are connected through a fourth spring;

the first spring and the third spring are symmetrically arranged on or near an X-direction symmetry axis of the second detection part; the second spring and the fourth spring are symmetrically arranged on or near an X-direction symmetry axis of the third detection part;

the first spring, the second spring, the third spring and the fourth spring have elasticity in the Y direction and can be pressed or stretched in the Y direction.

Optionally, the first spring, the second spring, the third spring and the fourth spring are folded springs.

Further, the suspension device also comprises a third arm and a fourth arm which are symmetrically arranged; the two ends of the third arm are respectively connected with the first section of the first arm and the first section of the second arm, and the two ends of the fourth arm are respectively connected with the third section of the first arm and the third section of the second arm.

Further, the third arm is connected with the first corner anchor point and the second corner anchor point through the first connecting beam and the second connecting beam respectively; the fourth arm is connected with a third corner anchor point and a fourth corner anchor point through a third connecting beam and a fourth connecting beam respectively;

the first, second, third and fourth connection beams are arranged to increase the stiffness of the suspension in the X-direction. Wherein the four connecting beams are arranged in an extending way along the X direction.

Further, the first arm second section and the second arm second section are respectively connected with a first middle anchor point and a second middle anchor point which are arranged on the substrate through connecting beams. Two connecting beams are connected to intermediate or substantially intermediate positions of the first arm second section and the second arm second section, respectively.

Further, the second detection portion and the third detection portion are connected with the first detection portion through a first spring and a second spring, respectively, the first spring and the second spring can transmit driving forces of the second detection portion and the third detection portion to the first detection portion;

the first detection unit includes:

the first mass block is connected to a group of anchor points fixed on the substrate through a group of connecting beams, and the connecting beams enable the first mass block to rotate in an XY plane around the center of the structure and rotate close to or far from the substrate; and

the first detection device group is a capacitor group formed by an electrode and a first mass block which are arranged on the substrate.

Further, the second detection section includes:

a first frame;

the second mass block is arranged in the first frame and connected with the first frame through at least two groups of springs, and the at least two groups of springs have degrees of freedom in the Y direction;

at least one first driving device arranged inside the second mass;

the second detection device group is arranged inside the second mass block;

the third detection unit includes:

a second frame;

the third mass block is arranged in the second frame and connected with the second frame through at least two groups of springs, and the at least two groups of springs have degrees of freedom in the Y direction;

at least one second driving device arranged inside the third mass;

the third detection device group is arranged inside the third mass block;

wherein the driving directions of the at least one first driving device and the at least one second driving device are opposite.

Further, the first frame is connected to the suspension means by at least two sets of springs; the second frame is connected to the suspension means by at least two sets of springs; at least two sets of springs have degrees of freedom in the X direction.

Further, the first driving device includes: a first driving structure for driving the second detecting part to move; and a first drive detection structure for detecting a drive amplitude of the first drive structure;

the second driving device includes: the second driving structure is used for driving the third detection part to move; and a second drive detection structure for detecting a drive amplitude of the second drive structure;

or the first driving device and the second driving device only comprise a group of movable comb teeth groups and fixed comb teeth groups, and driving detection are realized in a time-sharing multiplexing mode;

the second detection device group and the third detection device group each include:

the Y-direction detection capacitor group is used for detecting the angular velocity around the Y direction and consists of an electrode arranged on a substrate, a second mass block and a third mass block, or consists of a comb tooth group arranged on the substrate and a comb tooth group arranged on the second mass block and the third mass block; and

the Z-direction detection capacitor group for detecting the angular velocity around the Z direction consists of a movable comb tooth group arranged on the second mass block and the third mass block and a fixed comb tooth group connected to an anchor point.

Optionally, the Z-direction detecting capacitor set is disposed in a middle or approximately middle position of the second mass block and the third mass block, and the two Y-direction detecting capacitor sets are symmetrically disposed on two sides of the Z-direction detecting capacitor set.

Optionally, the driving and detecting modes are one or more of static electricity, piezoelectricity, piezoresistance, magnetism and heat.

The triaxial MEMS gyroscope has the following advantages:

1) The first arm and the second arm of the suspension device are respectively composed of three sections and springs, so that the first arm and the second arm of the suspension device can be bent when detecting the angular velocity around the Y direction, and the second detection part and the third detection part can keep parallel or approximately parallel to the substrate when moving along the Z direction, thereby improving the variability of the setting position of the Y-direction detection capacitor bank. Meanwhile, compared with the mode that the mass block rotates in the prior art, the displacement of the mass block at the position close to the rotation center is small, the detected capacitance value change is also small, and in the embodiment of the invention, the whole second detection part and the third detection part move up and down relative to the substrate, so that the capacitance value change of any one position of the second detection part and the third detection part is the same or basically the same, and the detection accuracy is improved to a certain extent.

2) The third arm and the fourth arm of the suspension device are respectively connected to the corner anchor point through a connecting beam extending along the X direction, the connecting beam increases the rigidity of the suspension device in the X direction, and the suspension device is reduced or avoided from moving along the X direction, so that the double frequency problem caused by the displacement in the Y direction is reduced or avoided.

3) The mass blocks for detecting the angular speeds around the Y direction and the Z direction are shared, and the mass of the shared mass blocks is increased relative to the mass block mode of separating the axes, so that the output signal caused by the movement of the shared mass blocks is strong, the signal quality of the gyroscope is improved, and meanwhile, the noise can be reduced;

4) The movable comb tooth group of the driving device is connected with the second mass block and the third mass block, so that the masses of the second mass block and the third mass block are increased, the mass of an output signal is increased, and meanwhile, noise can be reduced;

5) Because the whole structure layout is used, the MEMS gyroscope has compact structure, small whole area and lower production cost.

The conception, specific structure, and technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, features, and effects of the present invention.

Drawings

FIG. 1 is a schematic diagram of a three-axis MEMS gyroscope in an embodiment of the invention;

fig. 2 is an enlarged view of a part of the structure of the tri-axis MEMS gyroscope of fig. 1.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings in the specification, so that the technical contents thereof are more clearly and conveniently understood. The present invention may be embodied in many different forms of embodiments and the scope of the present invention is not limited to only the embodiments described herein.

The dimensions and thickness of each component shown in the drawings are arbitrarily shown, and the present invention is not limited to the dimensions and thickness of each component. The thickness of the components is exaggerated in some places in the drawings for clarity of illustration.

It should be understood that herein, "connected" may refer to two elements being directly connected, or may refer to two elements being indirectly connected through a third element.

Furthermore, the word "comprising" or "comprises" does not exclude the presence of elements or steps not listed. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The terms "first," "second," "third," and the like, herein, are used to modify a corresponding element, and do not, per se, mean that the element has any ordinal number, nor does it represent the order in which an element is ordered from another element, or the order in which it is manufactured, and use of such ordinal numbers merely serves to distinguish one element having a certain name from another element having the same name.

The first set of detection means is also referred to herein as the X-direction detection capacitor set. Z+ is the direction facing out of the paper, Z-is the direction facing into the paper; y+ is upward and Y-is downward.

As shown in fig. 1 and 2, the structure of the tri-axial MEMS gyroscope of the present embodiment is centrosymmetric, and includes a substrate (not shown in the drawings), a first detecting portion, a second detecting portion, a third detecting portion, and a suspension device.

The first detection section comprises a first mass 101 and a first set of detection means. Wherein the first set of detection means can be used for detecting angular velocity around the X-direction, comprising two X-direction capacitive sets of a first electrode 104 and a second electrode 105 arranged on the substrate and a first mass 101. The first mass 101 may be divided into three parts, a first side wing part, a middle part and a second side wing part, which are square or rectangular in configuration, connected to the middle part by a section of connecting arm, respectively, which is slightly thinner than the side wing parts. The first electrode 104 corresponds to a first lateral wing portion and the second electrode 105 corresponds to a second lateral wing portion, optionally the first electrode 104 and the second electrode 105 have a slightly larger area than the first lateral wing portion and the second lateral wing portion, thereby reducing capacitance value variations due to the first lateral wing portion and the second lateral wing portion due to movement beyond the area of the first electrode 104 and the second electrode 105 when the first mass 101 is driven and detected.

In some embodiments, the first and second wing portions may also be other configurations, such as oval, etc. In other embodiments, the first mass 101 may have a generally rectangular or square configuration, with the length extending in the X-direction if in the rectangular configuration. The first electrode 104 and the second electrode 105 are disposed on the substrate corresponding to both ends of the first mass 101 in the longitudinal direction.

As shown in fig. 2, a hole is provided in the middle portion of the first mass 101, fifth and sixth connection beams 102 and 103 are provided in the hole, and first and second anchor points 157 and 158 fixed to the base also correspond to the hole. The first mass 101 is connected to the connecting beam between the first anchor point 157 and the second anchor point 158 by a fifth connecting beam 102 and a sixth connecting beam 103, such that the first mass 101 is suspended and movable relative to the substrate. The fifth and sixth connection beams 102 and 103 extend in the Y direction and are symmetrically disposed on both sides of the connection beam between the first and second anchor points 157 and 158 to be orthogonal thereto. The fifth and sixth connection beams 102 and 103 have a certain variability, and can twist in the XY plane or rotate about the Y direction at the angular velocity of the drive or about the X direction.

With continued reference to fig. 1, the second detecting portion and the third detecting portion are symmetrically disposed on both sides of the first detecting portion in the Y direction and are respectively connected to the first detecting portion.

The second detecting portion includes a first frame 112 provided at the periphery, a second mass 111 provided inside the first frame 112, two first driving devices 113 and 114 provided inside the second mass 111, and a second detecting device group. The second mass 111 is connected to the first frame 112 by springs connected at or near the four corners, which have a degree of freedom in the Y direction, which in this embodiment are U-shaped springs.

Two first driving means 113 and 114 are symmetrically arranged on the second mass 111 in the X direction for driving the second mass to reciprocate in the X direction. Each first driving device comprises a first driving structure and a first driving detection structure, wherein the first driving structure provides driving force, and the first driving detection structure is used for detecting the driving amplitude of the first driving structure. The first driving structure comprises a first driving movable comb tooth set and a first driving fixed comb tooth set, the first driving detection structure comprises a first driving detection movable comb tooth set and a first driving detection fixed comb tooth set, the fixed comb tooth set is fixed on an anchor point, and the movable comb tooth set is fixedly arranged on the second mass block 111. The first driving fixed comb tooth group and the first driving detection fixed comb tooth group are arranged in a back-to-back mode. In some embodiments, each first driving device only includes a fixed comb set and a movable comb set, and the driving and driving detection functions are implemented by a time-sharing multiplexing mode.

In some embodiments, two first driving structures of two first driving devices may be located at one end of the second mass 111, and two first driving detection devices may be located at the other end of the second mass 111. In some embodiments, the second detecting portion may further include only one first driving device, which includes only one first driving structure and one first driving detecting structure, where the first driving structure is located at one end of the second mass 111, and the first driving detecting structure is symmetrically disposed at the other end of the second mass 111.

The second detection device group includes a Z-direction detection capacitor group 115 disposed in the middle of the second mass block 111, and two Y-direction detection capacitor groups composed of a third electrode 116 and a fourth electrode 117 disposed on the substrate and the second mass block 111, the two Y-direction detection capacitor groups being symmetrically disposed with respect to the Z-direction detection capacitor group. In this embodiment, the third electrode 116 and the fourth electrode 117 correspond to the middle positions of the two long sides of the second mass 111. In some embodiments, two Y-direction detection capacitor sets may be disposed at other positions of the second mass 111, or only one Y-direction detection capacitor may be disposed. In this embodiment, the Z-direction detection capacitor group 115 includes a first Z-direction detection capacitor 115a and a second Z-direction detection capacitor 115b symmetrically disposed with respect to the X-direction symmetry axis of the first mass. The fixed comb-tooth set of the Z-direction detection capacitor is fixed on the anchor point, and the movable comb-tooth set is fixedly connected to the second mass block 111. The two Z-direction detection capacitances are set such that when the second mass 111 moves upward in the Y-direction, the capacitance value of the first Z-direction detection capacitance 115a becomes smaller and the capacitance value of the second Z-direction detection capacitance 115b becomes larger. In some embodiments, the capacitance values of the first Z-direction detection capacitor 115a and the second Z-direction detection capacitor 115b may be increased or decreased simultaneously when the first mass moves along the Y-axis direction, or in some embodiments, the Z-direction detection capacitor group 115 includes only one detection capacitor.

The third detecting section is constructed similarly to the second detecting section and includes a second frame 122 provided at the periphery, a third mass 121 provided inside the second frame 122, two second driving devices 123 and 124 provided inside the third mass 121, and a third detecting device group. The third mass 121 is connected to the second frame 122 by springs connected at or near four corners, which have a degree of freedom in the Y direction, which in some embodiments may be U-shaped springs. The arrangement and possible variations of the two second driving means 123 and 124 are similar to those of the two first driving means and are not described here in detail.

The third detection device group includes a Z-direction detection capacitor group 125, and two Y-direction detection capacitor groups composed of a fifth electrode 126 and a sixth electrode 127 provided on the substrate and a third mass 121. The two Y-direction detecting capacitor sets and the Z-direction detecting capacitor set 125 are arranged in a similar manner to those of the second detecting device set, and are not described herein. In the present embodiment, the Z-direction detection capacitance group 125 includes a third Z-direction detection capacitance 125a and a fourth Z-direction detection capacitance 125b, both of which are set such that when the third mass 121 moves downward in the Y-direction, the capacitance value of the third Z-direction detection capacitance 125a becomes large and the capacitance value of the fourth Z-direction detection capacitance 125b becomes small.

The first mass 101 is connected to the first frame 111 by a fifth spring 106 and to the second frame 121 by a sixth spring 107. The connection points between the ends of the fifth spring 106 and the sixth spring 107 and the first mass 101, the first frame 111, and the second frame 121 are located at the middle or approximately middle positions of the respective sides. The fifth spring 106 and the sixth spring 107 are shaped like an "S", and when the first frame 112 and the second frame 122 are driven to move by the driving device, the movement can be transmitted to the first mass 101 through the fifth spring 106 and the sixth spring 107, and the driving movement directions of the first frame 112 and the second frame 122 are opposite, so that the first mass 101 is driven to perform a rotational movement in the XY plane. In some embodiments, the first spring 151 and the second spring 152 may also be other shapes.

The suspension device has a quadrangular structure, and is formed by connecting a first arm 131, a second arm 132, a third arm 133 and a fourth arm 134, and a first detecting portion, a second detecting portion and a third detecting portion are provided inside the quadrangular structure. Wherein the first arm 131 and the second arm 132 are symmetrically arranged, and the third arm 133 and the fourth arm 134 are symmetrically arranged.

The first arm 131 may be divided into a first arm first section 1311, a first arm second section 1312, and a first arm third section 1313, the first arm first section 1311 and the first arm second section 1312 being connected by a first spring 1314, the first arm second section 1312 and the first arm third section 1313 being connected by a second spring 1315. The second arm 132 includes a second arm first section 1321, a second arm second section 1322, and a second arm third section 1323, wherein the second arm first section 1321 and the second arm second section 1322 are connected by a third spring 1324, and the second arm second section 1322 and the second arm third section 1323 are connected by a fourth spring 1325.

The positions of the first spring 1314 and the third spring 1324 are on or near the X-direction symmetry axis of the second detection portion; the second spring 1315 and the fourth spring 1325 are positioned on or near the X-direction symmetry axis of the third detection portion. The first spring 1314, the second spring 1315, the third spring 1324, and the fourth spring 1325 have elasticity in the Y direction, i.e., can be pressed or stretched in the Y direction. In the present embodiment, the first spring 1314, the second spring 1315, the third spring 1324, and the fourth spring 1325 are folded springs, which are composed of adjacently disposed straight portions and curved portions connecting the respective straight portions. In other embodiments, the first spring 1314, the second spring 1315, the third spring 1324, and the fourth spring 1325 may have other shapes as long as they are capable of functioning as a connection and have elasticity in the Y direction.

One end of the first frame 112 of the second detection section is connected to the first arm first section 1311 through a seventh spring 141, to the first arm second section 1312 through an eighth spring 142, and the other end is connected to the second arm first section 1321 through a ninth spring 143, to the second arm second section 1322 through a tenth spring 144, and the seventh spring 141, the eighth spring 142, the ninth spring 143, and the tenth spring 144 have a degree of freedom in the X direction and have a certain Z-direction deformability. One end of the second frame 122 of the third detecting part is connected to the first arm second section 1312 through an eleventh spring 145, to the first arm third section 1313 through a twelfth spring 146, and the other end is connected to the second arm second section 1322 through a thirteenth spring 147, to the second arm third section 1323 through a fourteenth spring 148, and the eleventh spring 145, the twelfth spring 146, the thirteenth spring 147, and the fourteenth spring 148 have a degree of freedom in the X direction and have a certain Z-direction deformability.

The suspension device is connected to a set of anchor points fixed to the substrate, thereby effecting suspension of the suspension device relative to the substrate. Wherein the first arm second section 1312 is connected to the first intermediate anchor point 151 by a connecting beam, the connection point of the connecting beam and the first arm second section 1312 being located at the intermediate position of the first arm second section 1312; the second arm second section 1322 is connected to the second intermediate anchor point 152 by a connecting beam, the connection point of the connecting beam and the second arm second section 1322 being located in an intermediate position of the second arm second section 1322. The third arm 133 is connected to the first corner anchor 153 and the second corner anchor 154 by the first connecting beam 135 and the second connecting beam 136, respectively, and the connection points of the first connecting beam 135 and the second connecting beam 136 with the third arm 133 are near both ends of the third arm 133; the fourth arm 134 is connected to the third corner anchor point 155 and the fourth corner anchor point 156 via the third connecting beam 137 and the fourth connecting beam 138, respectively, and the connection points of the third connecting beam 137 and the fourth connecting beam 138 with the fourth arm 134 are near both end portions of the fourth arm 134. The first, second, third and fourth connection beams 135, 136, 137 and 138 extend in the X-direction, which can increase the rigidity of the suspension in the X-direction, reduce or avoid the movement of the suspension in the X-direction, and thus reduce or avoid the double frequency problem caused by the displacement in the Y-direction. The first, second, third and fourth connection beams 135, 136, 137 and 138 can undergo a certain torsional deformation in response to the movement of the suspension device when the angular velocity around the Y direction is detected.

When the gyroscope receives an angular velocity around the Y direction, the second detecting portion and the third detecting portion receive a coriolis force in the Z direction, and move in the Z direction. Since the first arm 131 and the second arm 132 connected to the second detection portion and the third detection portion are each divided into three sections, each two sections of one arm are connected by a spring, the first and second sections, the second section, and the third section of the first arm 131 and the second arm 132 may move toward or away from the substrate from a horizontal plane with the spring as a movement start point. Thus, when the second detection part and the third detection part move along the Z direction, the second detection part and the third detection part are kept parallel or approximately parallel to the substrate, so that the setting position of the Y-direction detection capacitor group does not or approximately not influence the detected capacitance value. In the prior art, the mass block generally rotates relative to the substrate, so that the displacement of the mass block is small at the position close to the rotation center, which tends to cause small capacitance value change, and if the detection capacitor group is arranged at the positions, the detection accuracy is affected. Therefore, by the flexibility of the first arm 131 and the second arm 132 of the suspension device, the second detection portion and the third detection portion are moved up and down with respect to the whole substrate, the variability of the setting position of the Y-direction detection capacitor bank is improved, and the accuracy of detection is also improved to some extent.

For example, when the second detecting portion receives the coriolis force in the Z direction and moves in the z+ direction, the first arm first section 1311 and the second arm first section 1321 move in the z+ direction near the end of the spring, and the end of the first arm first section 1311 far from the spring and the end of the second arm first section 1321 far from the spring are connected to the third arm 133, so that the positions of the first arm first section 1311 and the second arm first section 1321 are substantially fixed, and therefore, the first section and the second section form an obtuse angle shape with respect to the substrate, and the spring between the first section and the second section is deformed by being squeezed and stretched. Due to the above-mentioned movements of the first and second sections and the spring, the second detecting portion itself can be kept parallel or substantially parallel to the substrate when moving in the Z direction, so that the largest capacitance change can be detected regardless of the position at which the Y-direction detecting capacitor group is provided in the second detecting portion.

In the driving mode, the two first driving devices 113 and 114 and the two second driving devices 123 and 124 provide driving forces in opposite directions, so that the second mass block 111 and the third mass block 121 reciprocate in opposite directions along the X direction, and the first frame 112 and the second frame 122 connected with the first mass block 111 and the second mass block 121 are also driven to reciprocate in opposite directions along the X direction. Meanwhile, the first frame 112 and the second frame 122 drive the first mass block 101 to do reciprocating rotation motion in the XY plane through the fifth spring 106 and the sixth spring 107 respectively.

When the triaxial MEMS gyroscope receives an angular velocity around the X direction, the first mass 101 that is originally rotated on the XY plane by the driving device receives a coriolis force in the Z direction, and displacement in the Z direction occurs. Specifically, the displacement directions of the two ends of the first mass block 101 are opposite, the capacitance formed by the first electrode 104 and one end of the first mass block 101 and the capacitance formed by the second electrode 105 and the other end of the first mass block 101 form differential detection, if the one end of the first mass block 101 corresponding to the first electrode 104 moves in the direction away from the first electrode 104, the capacitance value at the first electrode 104 decreases, and at the moment, the one end of the first mass block 101 corresponding to the second electrode 105 moves in the direction approaching the second electrode 105, the capacitance value at the second electrode 105 increases. Thereby, the angular velocity around the X direction is detected by the X-direction detection capacitance group.

When the triaxial MEMS gyroscope receives an angular velocity around the Y direction, the second detection portion (the second mass block 111 and the first frame 112) and the third detection portion (the third mass block 121 and the second frame 122) that originally move along the X axis under the drive of the driving device receive a coriolis force along the Z direction, and displacement in the Z direction occurs. Specifically, the displacement directions of the second detection portion and the third detection portion in the Z direction are opposite, and the capacitance groups formed by the third electrode 116 and the fourth electrode 117 and the second mass block 111 and the capacitance groups formed by the fifth electrode 126 and the sixth electrode 127 and the third mass block 121 form differential detection. When the second detection unit moves to Z-, the capacitance values at the third electrode 116 and the fourth electrode 117 increase, and when the third detection unit moves to z+, the capacitance values at the fifth electrode 126 and the sixth electrode 127 decrease. And, since the second detecting portion and the third detecting portion remain parallel or substantially parallel to the substrate when moving along the Z direction, the capacitance values of the two Y-direction detecting capacitor groups of the second detecting portion are the same or substantially the same, and the capacitance values of the two Y-direction detecting capacitor groups of the third detecting portion are the same or substantially the same. Thereby, the angular velocity around the Y direction is detected by the Y-direction detection capacitance group.

When the triaxial MEMS gyroscope receives an angular velocity around the Z direction, the second detection portion (the second mass block 111 and the first frame 112) and the third detection portion (the third mass block 121 and the second frame 122) that originally move along the X axis under the drive of the driving device receive a coriolis force along the Y direction, and displacement in the Y direction occurs. Specifically, the displacement directions of the second detection portion and the third detection portion in the Y direction are opposite, and the first Z-direction detection capacitance 115a and the fourth Z-direction detection capacitance 125b form differential detection with the second Z-direction detection capacitance 115b and the third Z-direction detection capacitance 125 a. When the second detecting unit moves in the y+ direction and the third detecting unit moves in the Y-direction, the capacitance values at the first Z-direction detecting capacitor 115a and the fourth Z-direction detecting capacitor 125b decrease, and the capacitance values at the second Z-direction detecting capacitor 115b and the third Z-direction detecting capacitor 125a increase. Thereby, the angular velocity around the X direction is detected by the Z-direction detection capacitance.

The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention without requiring creative effort by one of ordinary skill in the art. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.

Claims (9)

1. A triaxial MEMS gyroscope, comprising:

a substrate;

a first detection unit for detecting an angular velocity around the X direction;

the second detection part and the third detection part are symmetrically arranged at two sides of the first detection part, are respectively connected with the first detection part, and are arranged to provide driving forces with opposite directions and can be used for detecting angular speeds around the Y direction and around the Z direction; wherein the X direction is perpendicular to the Y direction, and the Z direction is perpendicular to the X direction and the Y direction; and

the suspension device is suspended on the substrate through an anchor point group, is arranged outside the first detection part, the second detection part and the third detection part and is connected with the second detection part and the third detection part; the suspension device is arranged so that the second and third detection portions remain parallel or substantially parallel to the substrate when movement in the Z direction occurs to the second and third detection portions;

the suspension device comprises a first arm and a second arm which are symmetrically arranged;

the first arm comprises a first arm first section, a first arm second section and a first arm third section, wherein the first arm first section and the first arm second section are connected through a first spring, and the first arm second section and the first arm third section are connected through a second spring;

the second arm comprises a second arm first section, a second arm second section and a second arm third section, wherein the second arm first section and the second arm second section are connected through a third spring, and the second arm second section and the second arm third section are connected through a fourth spring;

the first spring and the third spring are symmetrically arranged on or near an X-direction symmetry axis of the second detection part; the second spring and the fourth spring are symmetrically arranged on or near an X-direction symmetry axis of the third detection part;

the first spring, the second spring, the third spring and the fourth spring have elasticity in the Y direction.

2. The tri-axis MEMS gyroscope of claim 1, wherein the first spring, the second spring, the third spring, and the fourth spring are folded springs.

3. The tri-axis MEMS gyroscope of claim 1, wherein the suspension further comprises third and fourth arms symmetrically disposed; and two ends of the fourth arm are respectively connected with the first arm third section and the second arm third section.

4. The tri-axis MEMS gyroscope of claim 3, wherein the third arm is connected to the first corner anchor and the second corner anchor by a first connection beam and a second connection beam, respectively; the fourth arm is connected with a third corner anchor point and a fourth corner anchor point through a third connecting beam and a fourth connecting beam respectively;

the first, second, third and fourth connection beams are arranged to increase the stiffness of the suspension in the X-direction.

5. The tri-axis MEMS gyroscope of claim 1, wherein the first arm second section and the second arm second section are connected by a connecting beam and a first intermediate anchor and a second intermediate anchor, respectively, disposed on a substrate.

6. The triaxial MEMS gyroscope according to claim 1, wherein the second and third detection portions are connected to the first detection portion by first and second springs, respectively, the first and second springs being capable of transmitting driving forces of the second and third detection portions to the first detection portion;

the first detection unit includes:

a first mass connected to a set of anchor points fixed to a base by a set of connecting beams that enable rotation of the first mass in an XY plane about a center of the structure and rotation toward or away from the base; and

the first detection device group is a capacitor group formed by an electrode and a first mass block which are arranged on the substrate.

7. The three-axis MEMS gyroscope of claim 1, wherein,

the second detection unit includes:

a first frame;

the second mass block is arranged inside the first frame and connected with the first frame through at least two groups of springs, and the at least two groups of springs have degrees of freedom in the Y direction;

at least one first driving device arranged inside the second mass block;

the second detection device group is arranged inside the second mass block;

the third detection section includes:

a second frame;

the third mass block is arranged inside the second frame and connected with the second frame through at least two groups of springs, and the at least two groups of springs have a degree of freedom in the Y direction;

at least one second driving device arranged inside the third mass block;

the third detection device group is arranged inside the third mass block;

wherein the driving directions of the at least one first driving device and the at least one second driving device are opposite.

8. The tri-axis MEMS gyroscope of claim 7, wherein the first frame is connected to the suspension device by at least two sets of springs; the second frame is connected to the suspension device by at least two sets of springs; the at least two sets of springs have a degree of freedom in the X-direction.

9. The three-axis MEMS gyroscope of claim 7,

the first driving device includes: a first driving structure for driving the second detecting part to move; and a first drive detection structure for detecting a drive amplitude of the first drive structure;

the second driving device includes: a second driving structure for driving the third detecting part to move; and a second drive detection structure for detecting a drive amplitude of the second drive structure;

or the first driving device and the second driving device only comprise a group of movable comb teeth groups and fixed comb teeth groups, and driving detection are realized in a time-sharing multiplexing mode;

the second detection device group and the third detection device group each include:

the Y-direction detection capacitor group is used for detecting the angular velocity around the Y direction and consists of an electrode arranged on a substrate, a second mass block and a third mass block, or consists of a comb tooth group arranged on the substrate and a comb tooth group arranged on the second mass block and the third mass block; and

the Z-direction detection capacitor group for detecting the angular velocity around the Z direction consists of a movable comb tooth group arranged on the second mass block and the third mass block and a fixed comb tooth group connected to an anchor point.

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