A tri-axial MEMS inertial sensor

Abstract

The application provides a triaxial MEMS inertial sensor, which comprises a substrate, a first mass block, a second mass block, an X-axis detection capacitor assembly, a Y-axis detection capacitor assembly and a Z-axis detection capacitor assembly, the first mass block and the second mass block are supported on the substrate through a support beam, the X-axis detection capacitor assembly is nested in the first mass block through a second vibration elastic piece, the Y-axis detection capacitor assembly comprises a Y-axis detection frame and at least two Y-axis detection electrode plates, the Y-axis detection frame is nested in the second mass block, the Y-axis detection electrode plates are connected to the substrate, and the projection part of the Y-axis detection frame on the substrate covers the Y-axis detection electrode plates, and the Z-axis detection capacitor assembly is arranged on the substrate corresponding to the first mass block and the second mass block. The application arranges three capacitor detection structures on the same substrate, realizes the detection of the movement in the three directions of X, Y and Z axes, the detection between the directions does not interfere with each other, the size of the device is reduced, and the detection accuracy of each axis is improved.

Description

Technical Field

[0001] This invention belongs to the field of inertial sensor technology, specifically relating to a triaxial MEMS inertial sensor. Background Technology

[0002] Inertial sensors include accelerometers, gyroscopes, and their single, dual, and three-axis combinations. Accelerometers are used to detect the acceleration signals of an object on three independent axes of the carrier coordinate system, while gyroscopes are used to detect the angular velocity signals of the carrier relative to the navigation coordinate system. By measuring the angular velocity and acceleration of the object in three-dimensional space, the attitude of the object can be accurately characterized, which has important application value in navigation.

[0003] Existing triaxial MEMS sensors are mostly composed of three discrete single-axis sensors combined separately. However, the overall area of ​​the discretely combined triaxial MEMS sensor is large, the space utilization is not high, which is not conducive to cost saving and miniaturization of the integrated system. Furthermore, there are process deviations between the discretely combined triaxial MEMS sensors, and it is difficult to guarantee the performance consistency between the three independent axes. Summary of the Invention

[0004] The purpose of this invention is to provide a triaxial MEMS inertial sensor that can at least solve some of the defects existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A triaxial MEMS inertial sensor includes a substrate, a first mass block, a second mass block, an X-axis sensing capacitor assembly, a Y-axis sensing capacitor assembly, and a Z-axis sensing capacitor assembly. The first and second mass blocks are supported on the substrate by a support beam, and a first vibration elastic element connects the first and second mass blocks. The X-axis sensing capacitor assembly is nested inside the first mass block via a second vibration elastic element. The Y-axis sensing capacitor assembly includes a Y-axis sensing frame and at least two Y-axis sensing plates. The Y-axis sensing frame is nested inside the second mass block, and the Y-axis sensing plates are connected to the substrate. The projection portion of the Y-axis sensing frame on the substrate covers the Y-axis sensing plates. The Z-axis sensing capacitor assembly is disposed on the substrate corresponding to the first and second mass blocks.

[0007] Furthermore, when the second mass block vibrates along the Y-axis, the overlapping area of ​​at least one of the Y-axis detection plates with the Y-axis detection frame increases, while the overlapping area of ​​at least one of the Y-axis detection plates with the Y-axis detection frame decreases.

[0008] Furthermore, there are two Y-axis detection plates, which are arranged in a parallel and staggered manner in the X-axis direction.

[0009] Further, a through hole is formed in the second mass block, the through hole penetrates the second mass block along the Z-axis direction, the Y-axis detection frame is located in the through hole, and two ends of the Y-axis detection frame along the X-axis direction are connected with the second mass block.

[0010] Further, when the triaxial MEMS inertial sensor vibrates along the Z-axis, the distance change amount between each Y-axis detection electrode plate and the Y-axis detection frame is the same.

[0011] Further, the X-axis detection capacitor assembly comprises an X-axis detection frame, at least two groups of X-axis detection moving comb teeth and at least two groups of X-axis detection fixed comb teeth arranged in the X-axis detection frame, the X-axis detection frame is connected with the first mass block through the second vibration elastic element, the X-axis detection moving comb teeth are connected to the X-axis detection frame, and the X-axis detection fixed comb teeth are fixed to the substrate through an anchor point; when the first mass block vibrates along the X-axis, the capacitance value between at least one group of the X-axis detection fixed comb teeth and the corresponding X-axis detection moving comb teeth increases, and the capacitance value between at least one group of the X-axis detection fixed comb teeth and the corresponding X-axis detection moving comb teeth decreases.

[0012] Further, the Z-axis detection capacitor assembly comprises at least one first electrode plate and at least one second electrode plate arranged on the substrate, each first electrode plate is arranged corresponding to the first mass block, and each second electrode plate is arranged corresponding to the second mass block.

[0013] Further, when the triaxial MEMS sensor vibrates along the Z-axis, the first mass block and the second mass block make opposite out-of-plane movements respectively, and the distance between the first mass block and the first electrode plate and the distance between the second mass block and the second electrode plate are increased and decreased respectively.

[0014] Further, the first mass block has a hollow structure.

[0015] Further, the support beam has two parallel arrangements, two ends of the support beam are fixed to the substrate through an anchor point, the first mass block and the second mass block are located between the two support beams, and two ends of the first vibration elastic element are connected to the two support beams respectively.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] In the triaxial MEMS inertial sensor of the present application, three capacitive detection structures are arranged on the same substrate to realize detection of movements in three directions along X, Y and Z axes, meanwhile, the vibration elastic members and the layout and structure design of the axial detection capacitive components make the detection of different directions not interfere with each other, the integrated triaxial MEMS sensor reduces the device area, the size of the overall structure and the final packaging size, the process deviation between different axes is small, the performance consistency between different axial directions is high, and the detection accuracy of each axial direction is improved.

[0018] The present application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of the triaxial MEMS inertial sensor of the present application;

[0020] Figure 2 is a vibration schematic diagram of the triaxial MEMS inertial sensor of the present application along the X axis;

[0021] Figure 3 is a vibration schematic diagram of the triaxial MEMS inertial sensor of the present application along the Y axis;

[0022] Figure 4 is a vibration schematic diagram of the triaxial MEMS inertial sensor of the present application along the Z axis.

[0023] Reference signs: 1, first mass block; 2, first vibration elastic member; 3, support beam; 4, second mass block; 5, first electrode plate; 6, second vibration elastic member; 7, X-axis detection frame; 8, X-axis detection moving comb tooth; 9, X-axis detection fixed comb tooth; 10, hollow square block; 11, anchor point; 12, second electrode plate; 13, Y-axis detection electrode plate; 14, Y-axis detection frame. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] In the description of the present application, it is to be understood by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0026] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be in contact with the connection or integrally connected; For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features; In the description of the present application, unless otherwise specified, the meaning of "multiple", "several" is two or more.

[0028] As Figures 1 to 4As shown, this embodiment provides a triaxial MEMS inertial sensor, including a substrate (not shown in the figure), a first mass block 1, a second mass block 4, an X-axis detection capacitor assembly, a Y-axis detection capacitor assembly, and a Z-axis detection capacitor assembly. The first mass block 1 and the second mass block 4 are both movable sensitive mass blocks. The first mass block 1 and the second mass block 4 are supported on the base by the support beam 3, and a first vibration elastic element 2 is connected between the first mass block 1 and the second mass block 4. Specifically, the first vibration elastic element 2 is fixed to the base by the anchor point 11 and is arranged in parallel between the first mass block 1 and the second mass block 4. Both the first mass block 1 and the second mass block 4 are connected to the first vibration elastic element 2. The X-axis detection capacitor assembly is nested inside the first mass block 1 by the second vibration elastic element 6. The Y-axis detection capacitor assembly includes a Y-axis detection frame 14 and at least two Y-axis detection plates 13. The Y-axis detection frame 14 is nested inside the second mass block 4. The Y-axis detection plates 13 are connected to the base, and the projection of the Y-axis detection frame 14 on the base covers the Y-axis detection plates 13. The Z-axis detection capacitor assembly is disposed on the base corresponding to the first mass block 1 and the second mass block 4. The Y-axis detection frame 14 can be made directly from electrode material, or it can have an electrode structure corresponding to each Y-axis detection electrode 13, so that the overlapping area between the Y-axis detection frame 14 and the Y-axis detection electrode 13 can form a detection capacitor.

[0029] In this embodiment, the first vibrating elastic element 2 can be, but is not limited to, a vibrating spring. The first vibrating elastic element 2 bends in the Y-axis direction, while simultaneously allowing the first mass block 1 and the second mass block 4 to move along the Z-axis direction. The second vibrating elastic element 6 can extend and retract along the X-axis direction, and can be, but is not limited to, a vibrating spring, a flexible U-beam, or an O-beam. Movement in the X and Y axes is in-plane movement parallel to the base, while movement in the Z-axis direction is out-of-plane movement. The X-axis direction is defined as... Figure 1 Left and right directions, Y-axis direction is Figure 1 The vertical direction and the Z-axis direction are as follows: Figure 1 The direction perpendicular to the front and back of the paper.

[0030] Specifically, such as Figures 2 to 4As shown, when the tri-axis MEMS inertial sensor vibrates along the X-axis, the second vibration elastic member 6 provides stiffness during vibration, the X-axis detection capacitor assembly moves in the X-axis direction, a change in the capacitance value is generated, and the tri-axis MEMS inertial sensor detects the X-direction parameter; when the tri-axis MEMS inertial sensor vibrates along the Y-axis, the overlapping area between the Y-axis detection frame 14 and the Y-axis detection electrode plate 13 changes, thereby generating a change in the capacitance value, and the tri-axis MEMS inertial sensor detects the Y-direction parameter; when the tri-axis MEMS inertial sensor vibrates along the Z-axis, the first mass block 1 and the second mass block 4 make opposite out-of-plane movements, respectively, the detection capacitance value generated between the Z-axis detection capacitor assembly and the corresponding mass block increases and decreases, two groups of capacitors form differential capacitors, the capacitance detection signal is increased, and the common mode error signal is reduced by difference, and the tri-axis MEMS inertial sensor accurately detects the Z-direction parameter. In this embodiment, three capacitance detection structures are arranged on the same substrate to realize XYZ-axis three-direction movement detection. This integrated tri-axis MEMS sensor reduces the device area, the overall structure size, and the final packaging size, and the process deviation between different axes is small, and the performance consistency between different axes is high.

[0031] In an optimized embodiment, when the second mass block 4 vibrates along the Y-axis, at least one Y-axis detection electrode plate 13 and the Y-axis detection frame 14 increase in overlapping area, and at least one Y-axis detection electrode plate 13 and the Y-axis detection frame 14 decrease in overlapping area. This structural design makes the detection capacitance value generated between the Y-axis detection frame 14 and the Y-axis detection electrode plate 13 at least increase and decrease, the increased and decreased capacitors form differential capacitors, the capacitance detection signal is increased, and the common mode error signal is reduced by difference, thereby improving the Y-axis direction capacitance detection precision.

[0032] In some embodiments, a specific structural design and layout of the Y-axis detection capacitor assembly is as shown in Figure 1 and Figure 3 As shown, a through hole is formed on the second mass block 4, the through hole penetrates the second mass block 4 along the Z-axis direction, the Y-axis detection frame 14 is located in the through hole, and the two ends of the Y-axis detection frame 14 in the X-axis direction are connected with the second mass block 4; the Y-axis detection electrode plate 13 has two, and the two Y-axis detection electrode plates 13 are arranged in parallel in the X-axis direction; when the second mass block 4 vibrates along the Y-axis, the capacitance formed between the Y-axis detection frame 14 and the two Y-axis detection electrode plates 13 increases and decreases, two groups of capacitors form differential capacitors, the capacitance detection signal is increased, and the common mode error signal is reduced by difference.

[0033] Further, the distance variation between each Y-axis detection electrode plate 13 and the Y-axis detection frame 14 is the same when the tri-axis MEMS inertial sensor vibrates along the Z-axis, and the Z-direction motion and the Y-direction motion are isolated from each other through this design. Specifically, taking two Y-axis detection electrode plates as an example, when the tri-axis MEMS inertial sensor vibrates along the Z-axis, the Y-axis detection frame 14 vibrates in the corresponding direction synchronously with the second mass block 4, and the relative positions of the two Y-axis detection electrode plates 13 and the Y-axis detection frame 14 are designed so that the distance variation between the Y-axis detection frame 14 and the two Y-axis detection electrode plates 13 is synchronous. In this way, the capacitance variation between the Y-axis detection frame 14 and the two Y-axis detection electrode plates 13 is synchronous, and the differential output is zero, i.e., the Y-direction capacitance value does not change, which indicates that the tri-axis MEMS sensor vibrating along the Z-axis has no effect on the Y-direction capacitance output, and the Z-direction motion and the Y-direction motion are isolated from each other without motion coupling.

[0034] Optionally, as shown in Figure 1 and Figure 2 The X-axis detection capacitor assembly includes an X-axis detection frame 7 and at least two groups of X-axis detection movable comb teeth 8 and at least two groups of X-axis detection fixed comb teeth 9 arranged in the X-axis detection frame 7. A through hole is formed in the first mass block 1, which penetrates the first mass block 1 along the Z-axis direction, and the through hole is preferably located at the center of the first mass block 1. The X-axis detection frame 7 is arranged in the through hole, and the two ends of the X-axis detection frame 7 along the X-axis direction are connected to the first mass block 1 through the second vibration elastic member 6, which can stretch and contract along the X-axis direction. The X-axis detection movable comb teeth 8 are connected to the X-axis detection frame 7, and the X-axis detection fixed comb teeth 9 are fixed to the substrate through the anchor point 11. The comb teeth of the X-axis detection fixed comb teeth 9 at least partially extend into the comb tooth gap of the corresponding X-axis detection movable comb teeth 8, and when the first mass block 1 vibrates along the X-axis, the capacitance value between at least one group of the X-axis detection fixed comb teeth 9 and the corresponding X-axis detection movable comb teeth 8 increases, and the capacitance value between at least one group of the X-axis detection fixed comb teeth 9 and the corresponding X-axis detection movable comb teeth 8 decreases. In this way, the capacitance value increases and decreases, and the differential capacitance is formed by the difference between the two capacitances, which increases the capacitance detection signal and simultaneously eliminates the common-mode error signal. In this embodiment, at least one group of X-axis detection movable comb teeth 8 is connected to the upper and lower sides of the X-axis detection frame 7, respectively. The comb tooth openings of the X-axis detection movable comb teeth 8 on the upper and lower sides both face along the X-axis direction and are opposite in direction. In this way, when the tri-axis MEMS sensor vibrates along the X-axis, the overlapping area of the X-axis detection movable comb teeth 8 on the upper side and the corresponding X-axis detection fixed comb teeth 9 and the overlapping area of the X-axis detection movable comb teeth 8 on the lower side and the corresponding X-axis detection fixed comb teeth 9 increase and decrease, respectively, i.e., the capacitance values of the upper and lower sides increase and decrease, respectively, and the differential capacitance is formed by the difference between the two capacitances. Moreover, when the first mass block 1 moves in the X-axis direction, as shown in Figure 2As shown, due to the support of the first vibration elastic member 2 and the second vibration elastic member 6, the vibration frequencies in three directions can be effectively separated, when the first mass 1 moves in the X-axis direction, the other positions of the three-axis MEMS sensor structure remain stationary, that is, the X-direction movement is isolated from the Y and Z-direction movements, without movement coupling, and the X-axis detection precision is improved.

[0035] In a preferred embodiment, the distance change between the X-axis detection moving comb teeth 8 and the corresponding X-axis detection fixed comb teeth 9 in each group is designed to be the same when the three-axis MEMS sensor vibrates along the Y-axis or the Z-axis. Specifically, when the three-axis MEMS sensor vibrates along the Y-axis or the Z-axis, the X-axis detection frame 7 vibrates in the corresponding direction synchronously with the first mass 1, the distance change between the upper X-axis detection moving comb teeth 8 and the corresponding X-axis detection fixed comb teeth 9 in the X-axis detection frame 7 is synchronous with the distance change between the lower X-axis detection moving comb teeth 8 and the corresponding X-axis detection fixed comb teeth 9, so that the capacitance changes of the upper and lower sides in the X-axis detection frame 7 are synchronous, the differential output is zero, that is, the capacitance value does not change, the vibration of the three-axis MEMS sensor along the Y-axis or the Z-axis has no effect on the X-direction capacitance output, and the Y or Z-direction movement is isolated from the X-direction movement, without movement coupling.

[0036] Optionally, as shown in Figure 1 and Figure 4 The Z-axis detection capacitance assembly includes at least one first electrode plate 5 and at least one second electrode plate 12 arranged on the substrate, each first electrode plate 5 is arranged corresponding to the first mass 1, and each second electrode plate 12 is arranged corresponding to the second mass 4. The first mass 1 and the second mass 4 can be directly made of electrode material, or the first mass 1 and the second mass 4 can be provided with electrode plate structures corresponding to the first electrode plate 5 and the second electrode plate 12, so that the overlapping area between the mass and the corresponding electrode plate can form a detection capacitance. When the three-axis MEMS sensor vibrates along the Z-axis, the first mass 1 and the second mass 4 make opposite out-of-plane movements, at this time, the distance between the first mass 1 and the first electrode plate 5 and the distance between the second mass 4 and the second electrode plate 12 increase and decrease respectively, that is, the detection capacitance increases and decreases, two groups of capacitances form a differential capacitance, which increases the capacitance detection signal, and at the same time, the differential subtraction eliminates the common mode error signal, realizing the accurate detection of the Z-direction parameter of the three-axis MEMS sensor.

[0037] Specifically, in the embodiment, the X-axis detection capacitor assembly and the Y-axis detection capacitor assembly are respectively located at the center of the first mass block 1 and the second mass block 4, the first electrode plate 5 has two, which are respectively arranged at the two ends of the X-axis detection capacitor assembly along the X-axis direction, and the second electrode plate 12 has two, which are respectively arranged at the two ends of the Y-axis detection capacitor assembly along the X-axis direction. Preferably, the two first electrode plates 5 and the two second electrode plates 12 are symmetrically arranged with respect to the first vibration elastic member 2.

[0038] When the triaxial MEMS sensor vibrates along the Z-axis, the X-axis detection frame 7 is nested in the first mass block 1, and the X-axis detection frame 7 vibrates synchronously with the first mass block 1. By designing the X-axis detection fixed comb teeth 9 on the upper side and the lower side of the X-axis detection frame 7, the change of the distance between the X-axis detection fixed comb teeth 9 on the upper side and the X-axis detection movable comb teeth 8 is synchronous with the change of the distance between the X-axis detection fixed comb teeth 9 on the lower side and the X-axis detection movable comb teeth 8. Thus, the capacitance change amount of the upper and lower sides of the X-axis detection frame 7 is synchronous, and the differential output is zero, that is, the capacitance value does not change, which indicates that the vibration of the triaxial MEMS sensor along the Z-axis has no effect on the X-direction capacitance output, and the Z-direction motion and the X-direction motion are isolated from each other without motion coupling. When the triaxial MEMS sensor vibrates along the Z-axis, the Y-axis detection frame 14 is nested in the second mass block 4, and the Y-axis detection frame 14 vibrates synchronously with the second mass block 4. By designing the relative positions of the two Y-axis detection electrode plates 13 and the Y-axis detection frame 14, the change of the distance between the Y-axis detection frame 14 and the two Y-axis detection electrode plates 13 is synchronous. Thus, the capacitance change amount between the Y-axis detection frame 14 and the two Y-axis detection electrode plates 13 is synchronous, and the differential output is zero, that is, the Y-direction capacitance value does not change, which indicates that the vibration of the triaxial MEMS sensor along the Z-axis has no effect on the Y-direction capacitance output, and the Z-direction motion and the Y-direction motion are isolated from each other without motion coupling.

[0039] In an optimized embodiment, the first mass block 1 is designed to have a hollow structure. In the embodiment, the hollow structure is a plurality of hollow squares 10 arranged in an array, which are formed by holes penetrating through the first mass block 1 along the Z-axis direction. The hollow structure designed on the first mass block 1 can make the masses of the first mass block 1 and the second mass block 4 not equal, thereby generating swing in the Z-direction, and can also reduce the damping of the Z-direction swing.

[0040] In the three-axis MEMS sensor of the embodiment, two support beams are designed and arranged in parallel, two ends of the support beam 3 are fixed on the substrate through the anchor point 11, the first mass 1 and the second mass 4 are located between the two support beams 3, and two ends of the first vibration elastic element 2 are connected to the two support beams 3 respectively. Through the design of the support beam 3, the movement of the first mass 1 and the second mass 4 is stably supported, and the detection accuracy of the three-axis MEMS sensor is improved.

[0041] It should be noted that in the present application, Figure 2 , Figure 3 and Figure 4 are the movement end state diagrams of movable components of the three-axis MEMS sensor along the X-axis, the Y-axis and the Z-axis respectively, and in order to reflect the movement effect, the movement displacement of the movable components in the diagram is exaggerated.

[0042] The above examples are only illustrative of the present application and do not constitute a limitation on the protection scope of the present application. Any design identical or similar to the present application falls within the protection scope of the present application.

Claims

1. A triaxial MEMS inertial sensor, characterized in that: The system includes a base, a first mass block, a second mass block, an X-axis detection capacitor assembly, a Y-axis detection capacitor assembly, and a Z-axis detection capacitor assembly. The first and second mass blocks are supported on the base by a support beam, and a first vibration elastic element connects the first and second mass blocks. The X-axis detection capacitor assembly is nested inside the first mass block via a second vibration elastic element. The Y-axis detection capacitor assembly includes a Y-axis detection frame and at least two Y-axis detection plates. The Y-axis detection frame is nested inside the second mass block, and the Y-axis detection plates are connected to the base. The projection of the Y-axis detection frame onto the base covers the Y-axis detection plates. The Z-axis detection capacitor assembly is disposed on the base corresponding to the first and second mass blocks.

2. The triaxial MEMS inertial sensor as described in claim 1, characterized in that: When the second mass block vibrates along the Y-axis, the overlapping area of ​​at least one of the Y-axis detection plates and the Y-axis detection frame increases, while the overlapping area of ​​at least one of the Y-axis detection plates and the Y-axis detection frame decreases.

3. The triaxial MEMS inertial sensor as described in claim 2, characterized in that: There are two Y-axis detection plates, which are arranged in parallel and staggered positions in the X-axis direction.

4. The triaxial MEMS inertial sensor as described in claim 2, characterized in that: The second mass block has a through hole that extends through the second mass block along the Z-axis. The Y-axis detection frame is located inside the through hole, and both ends of the Y-axis detection frame are connected to the second mass block along the X-axis.

5. The triaxial MEMS inertial sensor as described in claim 2, characterized in that: When the triaxial MEMS inertial sensor vibrates along the Z-axis, the distance between each Y-axis detection plate and the Y-axis detection frame changes by the same amount.

6. The triaxial MEMS inertial sensor as described in claim 1, characterized in that: The X-axis detection capacitor assembly includes an X-axis detection frame and at least two sets of X-axis detection movable comb teeth and at least two sets of X-axis detection fixed comb teeth disposed within the X-axis detection frame. The X-axis detection frame is connected to the first mass block via a second vibration elastic element. The X-axis detection movable comb teeth are connected to the X-axis detection frame, and the X-axis detection fixed comb teeth are fixed to the base via anchor points. When the first mass block vibrates along the X-axis, the capacitance value between at least one set of X-axis detection fixed comb teeth and the corresponding X-axis detection movable comb teeth increases, while the capacitance value between at least one set of X-axis detection fixed comb teeth and the corresponding X-axis detection movable comb teeth decreases.

7. The triaxial MEMS inertial sensor as described in claim 1, characterized in that: The Z-axis detection capacitor assembly includes at least one first electrode plate and at least one second electrode plate disposed on the substrate, with each first electrode plate arranged corresponding to the first mass block and each second electrode plate arranged corresponding to the second mass block.

8. The triaxial MEMS inertial sensor as described in claim 7, characterized in that: When the triaxial MEMS sensor vibrates along the Z-axis, the first mass block and the second mass block move in opposite directions out of plane, and the distance between the first mass block and the first electrode plate and the distance between the second mass block and the second electrode plate increase and decrease respectively.

9. The triaxial MEMS inertial sensor as described in claim 1, characterized in that: The first mass block has a hollow structure.

10. The triaxial MEMS inertial sensor as described in claim 1, characterized in that: There are two support beams arranged in parallel. The two ends of the support beams are fixed to the base by anchor points. The first mass block and the second mass block are located between the two support beams, and the two ends of the first vibrating elastic element are respectively connected to the two support beams.

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