A MEMS tri-axial sensor

Abstract

The application provides a MEMS three-axis 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 is nested in the second mass block through a third vibration elastic piece, 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 XYZ-axis three-direction motion detection, and the detection between directions does not interfere with each other. The integrated three-axis 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 axes is high, and the precision of each axis detection is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inertial sensors, and particularly relates to a MEMS three-axis sensor. BACKGROUND

[0002] Inertial sensors include accelerometers, gyroscopes and single, double and three-axis combinations thereof, wherein the accelerometer is used for detecting acceleration signals of an object in three independent axes of a carrier coordinate system, and the gyroscope is used for detecting angular velocity signals of the carrier relative to a navigation coordinate system, so that the angular velocity and acceleration of the object in three-dimensional space can be measured to accurately represent the attitude of the object, and the inertial sensor has important application value in navigation.

[0003] The existing three-axis sensors are mostly three separate single-axis sensors combined separately, however, the three-axis sensor combined separately has a large overall area and low space utilization, which is not conducive to cost saving and miniaturization of integrated systems, and the three-axis sensor combined separately has process deviations, and the performance consistency between the three independent axes is difficult to guarantee. SUMMARY

[0004] The application aims to provide a MEMS three-axis sensor, which can at least solve some defects in the prior art.

[0005] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0006] A MEMS three-axis sensor 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, and the first mass block and the second mass block are connected through a first vibration elastic member, the X-axis detection capacitor assembly is nested in the first mass block through a second vibration elastic member, the Y-axis detection capacitor assembly is nested in the second mass block through a third vibration elastic member, and the Z-axis detection capacitor assembly is arranged on the substrate corresponding to the first mass block and the second mass block.

[0007] Further, the X-axis detection capacitor assembly and the Y-axis detection capacitor assembly are both comb structures, and the Z-axis detection capacitor assembly is a plate structure.

[0008] Further, the X-axis detection capacitor assembly comprises an X-axis detection frame and 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 a second vibration elastic member, 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.

[0009] Further, when the MEMS three-axis sensor vibrates along the Y axis or the Z axis, the distance change amount between each group of the X-axis detection moving comb teeth and the corresponding X-axis detection fixed comb teeth is the same.

[0010] Further, the Y-axis detection capacitor assembly comprises a Y-axis detection frame and at least two groups of Y-axis detection moving comb teeth and at least two groups of Y-axis detection fixed comb teeth arranged in the Y-axis detection frame, the Y-axis detection frame is connected with the second mass block through a second vibration elastic member, the Y-axis detection moving comb teeth are connected to the Y-axis detection frame, and the Y-axis detection fixed comb teeth are fixed to the substrate through an anchor point.

[0011] Further, when the second mass block vibrates along the Y axis, the capacitance value between at least one group of the Y-axis detection fixed comb teeth and the corresponding Y-axis detection moving comb teeth increases, and the capacitance value between at least one group of the Y-axis detection fixed comb teeth and the corresponding Y-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 three-axis MEMS sensor vibrates along the Z axis, the first mass block and the second mass block respectively make opposite out-of-plane movements, 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.

[0014] Further, the X-axis detection capacitor assembly and the Y-axis detection capacitor assembly are respectively located at the center of the first mass block and the second mass block, the first electrode plate has two and is arranged at two ends of the X-axis detection capacitor assembly in the X-axis direction, and the second electrode plate has two and is arranged at two ends of the Y-axis detection capacitor assembly in the X-axis direction.

[0015] Further, the first mass block has a hollow structure.

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

[0017] In the MEMS triaxial 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, and meanwhile, the layout and structure design of the three vibration elastic members and the axial detection capacitive components make the detection of different directions not interfere with each other. This integrated triaxial sensor reduces the device area, the overall structure size and the final packaging size, has small process deviation between different axial directions, high performance consistency between different axial directions, improves the detection accuracy of each axial direction and enhances the overall performance of the sensor.

[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 MEMS triaxial sensor of the present application;

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

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

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

[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, second electrode plate; 12, third vibration elastic member; 13, Y axis detection frame; 14, Y axis detection fixed comb tooth; 15, Y axis detection moving comb tooth; 16, anchor point. 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 devices or elements 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 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 indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features; In the description of the present application, unless otherwise stated, the meaning of "multiple", "several" is two or more.

[0028] As Figure 1 shown, the embodiment provides a MEMS three-axis sensor, which comprises a substrate (not shown in the figure), a first mass 1, a second mass 4, an X-axis detection capacitor assembly, a Y-axis detection capacitor assembly and a Z-axis detection capacitor assembly; wherein the first mass 1 and the second mass 4 are movable sensitive masses, the first mass 1 and the second mass 4 are supported on the substrate by a support beam 3, and the first mass 1 and the second mass 4 are connected by a first vibration elastic element 2, specifically, the first vibration elastic element 2 is fixed on the substrate by an anchor point 16, the first vibration elastic element 2 is arranged in parallel between the first mass 1 and the second mass 4, and the first mass 1 and the second mass 4 are connected with the first vibration elastic element 2; The X-axis detection capacitor assembly is nested in the first mass 1 by a second vibration elastic element 6, the Y-axis detection capacitor assembly is nested in the second mass 4 by a third vibration elastic element 12, and the Z-axis detection capacitor assembly is arranged on the substrate corresponding to the first mass 1 and the second mass 4.

[0029] In the embodiment, the first vibration elastic member 2 can adopt but is not limited to a vibration spring, which can allow the first mass block 1 and the second mass block 4 to move along the Z-axis direction; the second vibration elastic member 6 and the third vibration elastic member 12 can be stretched and contracted along the corresponding direction (i.e., the X-axis direction and the Y-axis direction), and can adopt but are not limited to a vibration spring, a stretchable and bendable U-shaped beam or an O-shaped beam, etc.; for example, when the triaxial sensor vibrates along the X-axis direction, the second vibration elastic member 6 can be stretched and contracted along the X-axis direction, and when the triaxial sensor vibrates along the Y-axis direction, the third vibration elastic member 12 can be stretched and contracted along the Y-axis direction; the X-axis and Y-axis direction movements are in-plane movements parallel to the substrate, and the Z-axis direction movement is an out-of-plane movement, and the X-axis direction is defined as Figure 1 the left-right direction, the Y-axis direction is defined as Figure 1 the up-down direction, and the Z-axis direction is defined as Figure 1 the front-back direction perpendicular to the paper.

[0030] Specifically, as shown in Figures 2 to 4 when the triaxial sensor vibrates along the X-axis, the second vibration elastic member 6 provides the stiffness during vibration, the X-axis detection capacitor assembly moves along the X-axis direction, a capacitance value changes, and the detection of the X-axis parameter of the triaxial sensor is realized; when the triaxial sensor vibrates along the Y-axis, the third vibration elastic member 12 provides the stiffness during vibration, the Y-axis detection capacitor assembly moves along the Y-axis direction, a capacitance value changes, and the detection of the Y-axis parameter of the triaxial sensor is realized; when the triaxial sensor vibrates along the Z-axis, the first mass block 1 and the second mass block 4 make opposite out-of-plane movements, the detection capacitances between the Z-axis detection capacitor assembly and the corresponding mass block increase and decrease, two groups of capacitors form a differential capacitor, the capacitance detection signal is increased, and the common mode error signal is subtracted, and the accurate detection of the Z-axis parameter of the triaxial sensor is realized. In the embodiment, three capacitance detection structures are arranged on the same substrate to realize the detection of the XYZ-axis three direction movements, the integrated triaxial 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 axes is high, and the overall performance of the sensor is improved.

[0031] Meanwhile, through the layout and structure design of the first vibration elastic member 2, the second vibration elastic member 6, the third vibration elastic member 12, the X-axis detection capacitor assembly, the Y-axis detection capacitor assembly and the Z-axis detection capacitor assembly, the triaxial sensor can not interfere with each other when moving in three directions, there is no motion coupling, and the detection accuracy of each axis is improved. In some embodiments, the X-axis detection capacitor assembly and the Y-axis detection capacitor assembly can be designed as comb structures, and the Z-axis detection capacitor assembly can be designed as a plate structure.

[0032] Optionally, as shown in Figure 1 and Figure 2As shown, the X-axis detection capacitor assembly comprises an X-axis detection frame 7 and at least two groups of X-axis detection moving 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 1, which penetrates the first mass 1 along the Z-axis direction, and the through hole is preferably located at the center of the first mass 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 1 through the second vibration elastic members 6, which can stretch and contract along the X-axis direction. The X-axis detection moving 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 anchor points 16. 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 moving comb teeth 8. When the first mass 1 vibrates along the X-axis, the capacitance between at least one group of the X-axis detection fixed comb teeth 9 and the corresponding X-axis detection moving comb teeth 8 increases, and the capacitance between at least one group of the X-axis detection fixed comb teeth 9 and the corresponding X-axis detection moving comb teeth 8 decreases. In this way, the capacitances increase and decrease, the differential capacitance is formed by subtracting the two capacitances, the capacitance detection signal is increased, and the common mode error signal is subtracted. In this embodiment, at least one group of X-axis detection moving comb teeth 8 is connected to the upper and lower sides of the X-axis detection frame 7. The comb tooth openings of the X-axis detection moving comb teeth 8 on the upper and lower sides face along the X-axis direction and in opposite directions. When the three-axis sensor vibrates along the X-axis, the overlapping area of the X-axis detection moving comb teeth 8 on the upper side and the corresponding X-axis detection fixed comb teeth 9 increases, and the overlapping area of the X-axis detection moving comb teeth 8 on the lower side and the corresponding X-axis detection fixed comb teeth 9 decreases. That is, the capacitances on the upper and lower sides increase and decrease, respectively, and the differential capacitance is formed by subtracting the capacitances at both ends. Moreover, when the first mass 1 moves along the X-axis direction, the vibration frequencies of the three directions can be effectively separated due to the isolation effect of the first vibration elastic member 2 and the third vibration elastic member 12. When the first mass 1 moves along the X-axis direction, the other positions of the three-axis sensor structure remain unchanged, that is, the X-direction movement is isolated from the Y- and Z-direction movements, there is no movement coupling, and the X-axis detection precision is improved.

[0033] In the preferred embodiment, the distance variation between each group of the X-axis detection movable comb teeth 8 and the corresponding X-axis detection fixed comb teeth 9 is designed to be the same when the MEMS three-axis sensor vibrates along the Y-axis or the Z-axis. Specifically, when the MEMS three-axis 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 block 1, and the distance variation between the upper X-axis detection movable comb teeth 8 and the corresponding X-axis detection fixed comb teeth 9 in the X-axis detection frame 7 is designed to be synchronous with the distance variation between the lower X-axis detection movable comb teeth 8 and the corresponding X-axis detection fixed comb teeth 9 in the X-axis detection frame 7. In this way, the capacitance variation of the upper and lower X-axis detection movable comb teeth 8 in the X-axis detection frame 7 is synchronous, and the differential output is zero, i.e., the capacitance value does not change. The vibration of the MEMS three-axis sensor along the Y-axis or the Z-axis has no effect on the X-direction capacitance output, and the Y or Z direction motion and the X direction motion are isolated from each other without motion coupling.

[0034] As shown in the optional embodiment, Figure 1 and Figure 3 The Y-axis detection capacitor assembly includes a Y-axis detection frame 13 and at least two groups of Y-axis detection movable comb teeth 15 and at least two groups of Y-axis detection fixed comb teeth 14 arranged in the Y-axis detection frame 13. A through hole is formed in the second mass block 4, which penetrates the second mass block 4 along the Z-axis direction. The through hole is preferably located at the center of the second mass block 4, and the Y-axis detection frame 13 is arranged in the through hole. The two ends of the Y-axis detection frame 13 along the Y-axis direction are connected to the second mass block 4 through the third vibration elastic member 12, and the third vibration elastic member 12 can stretch and contract along the Y-axis direction. The Y-axis detection movable comb teeth 15 are connected to the Y-axis detection frame 13, and the Y-axis detection fixed comb teeth 14 are fixed to the substrate through the anchor point 16. The Y-axis detection fixed comb teeth 14 are at least partially inserted into the comb tooth gap of the corresponding Y-axis detection movable comb teeth 15, and the capacitance value between at least one group of the Y-axis detection fixed comb teeth 14 and the corresponding Y-axis detection movable comb teeth 15 increases while the capacitance value between at least one group of the Y-axis detection fixed comb teeth 14 and the corresponding Y-axis detection movable comb teeth 15 decreases when the second mass block 4 vibrates along the Y-axis. 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 reduces the common mode error signal. In this embodiment, at least one group of Y-axis detection movable comb teeth 15 is connected to the left and right sides of the Y-axis detection frame 13, respectively. The comb tooth openings of the Y-axis detection movable comb teeth 15 on the left and right sides face along the Y-axis direction and in opposite directions. In this way, when the three-axis sensor vibrates along the Y-axis, the overlapping area of the Y-axis detection movable comb teeth 15 on the left side and the corresponding Y-axis detection fixed comb teeth 14 increases while the overlapping area of the Y-axis detection movable comb teeth 15 on the right side and the corresponding Y-axis detection fixed comb teeth 14 decreases, i.e., the capacitance values on the left and right sides increase and decrease, respectively, and the differential capacitance is formed by the difference between the two capacitances.

[0035] Further, the distance change amount between each group of the Y-axis detection movable comb teeth 15 and the corresponding Y-axis detection fixed comb teeth 14 can be designed to be the same when the MEMS three-axis sensor vibrates along the Z-axis, so as to realize mutual isolation of the Z-direction motion and the Y-direction motion. Specifically, when the MEMS three-axis sensor vibrates along the Z-axis and the Y-axis detection frame 13 vibrates in the corresponding direction synchronously with the second mass block 4, the distance change between the Y-axis detection movable comb teeth 15 on the left side of the Y-axis detection frame 13 and the corresponding Y-axis detection fixed comb teeth 14 is synchronous with the distance change between the Y-axis detection movable comb teeth 15 on the right side of the Y-axis detection frame 13 and the corresponding Y-axis detection fixed comb teeth 14, so that the capacitance change amount on the left side and the right side of the Y-axis detection frame 13 is synchronous, the differential output is zero, that is, the capacitance value does not change, the vibration of the MEMS three-axis sensor along the Z-axis has no effect on the Y-direction capacitance output, and mutual isolation of the Z-direction motion and the Y-direction motion is realized, without motion 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 11 arranged on the substrate, each of the first electrode plates 5 is arranged corresponding to the first mass block 1, each of the second electrode plates 11 is arranged corresponding to the second mass block 4, and the projection of the electrode plate structure on the first mass block 1 and the second mass block 4 on the substrate completely covers the corresponding first electrode plate 5 or second electrode plate 11 in the initial state; wherein the first mass block 1 and the second mass block 4 can be directly made of electrode material, or the electrode plate structure corresponding to the first electrode plate 5 and the second electrode plate 11 can be arranged on the first mass block 1 and the second mass block 4, so that the overlapping area between the mass block and the corresponding electrode plate can form a detection capacitance. When the three-axis sensor vibrates along the Z-axis, the first mass block 1 and the second mass block 4 perform opposite out-of-plane motions, at this time, the distance between the first mass block 1 and the first electrode plate 5 and the distance between the second mass block 4 and the second electrode plate 11 increase and decrease respectively, that is, the generated 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 accurate detection of the Z-direction parameter of the three-axis sensor.

[0037] Specifically, in the embodiment, the X-axis detection capacitance assembly and the Y-axis detection capacitance 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 and is arranged at two ends of the X-axis detection capacitance assembly along the X-axis direction, and the second electrode plate 11 has two and is arranged at two ends of the Y-axis detection capacitance assembly along the X-axis direction. Preferably, the two first electrode plates 5 and the two second electrode plates 11 are arranged symmetrically with respect to the first vibration elastic member 2.

[0038] When the triaxial sensor vibrates along the Z axis, because the X axis detection frame 7 is nested inside the first mass 1, the X axis detection frame 7 vibrates synchronously with the first mass 1, by designing the X axis detection fixed comb teeth 9 on the upper and lower sides of the X axis detection frame 7, so that the change in the spacing between the upper X axis detection fixed comb teeth 9 and the X axis detection movable comb teeth 8 is synchronous with the change in the spacing between the lower X axis detection fixed comb teeth 9 and the X axis detection movable comb teeth 8, that is, the capacitance change is synchronous, the differential output is zero, and the capacitance value does not change, indicating that the triaxial sensor vibrating 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. Similarly, when the triaxial sensor vibrates along the Z axis, the effect on the Y axis detection frame 13 is similar to that of the X axis detection frame 7, that is, 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 1 is designed to have a hollow structure, in this embodiment, the hollow structure is a plurality of hollow squares 10 arranged in an array, which are formed by holes penetrating the first mass 1 along the Z axis direction; the hollow structure designed on the first mass 1 in this embodiment can make the masses of the first mass 1 and the second mass 4 unequal, thereby generating oscillation in the Z direction; on the other hand, the hollow structure design can reduce the damping of the Z direction oscillation.

[0040] In an optimized embodiment, the MEMS triaxial sensor of this embodiment is designed with two parallel support beams 3, the two ends of the support beam 3 are fixed to the substrate through the anchor point 16, the first mass 1 and the second mass 4 are located between the two support beams 3, and the two ends of the first vibration elastic member 2 are connected to the two support beams 3 respectively, through the design of the support beam 3, the motion of the first mass 1 and the second mass 4 is stably supported, and the detection accuracy of the triaxial sensor is improved.

[0041] It should be noted that in the present application, Figure 2 、 Figure 3 and Figure 4 are the movement final state diagrams of the movable parts of the MEMS triaxial sensor vibrating along the X axis, Y axis and Z axis respectively, and in order to reflect the motion effect, the movement displacement of the movable parts in the figure 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 MEMS triaxial 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 through a second vibration elastic element, and the Y-axis detection capacitor assembly is nested inside the second mass block through a third vibration elastic element. The Z-axis detection capacitor assembly is located on the base corresponding to the first and second mass blocks.

2. The MEMS triaxial sensor as described in claim 1, characterized in that: The X-axis and Y-axis detection capacitor components are both comb-tooth structures, while the Z-axis detection capacitor component is an electrode plate structure.

3. The MEMS triaxial sensor as described in claim 2, 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.

4. The MEMS triaxial sensor as described in claim 3, characterized in that: When the MEMS triaxial sensor vibrates along the Y-axis or Z-axis, the spacing between the moving comb teeth of the X-axis detection and the corresponding fixed comb teeth of the X-axis detection in each group changes by the same amount.

5. The MEMS triaxial sensor as described in claim 2, characterized in that: The Y-axis detection capacitor assembly includes a Y-axis detection frame and at least two sets of Y-axis detection moving comb teeth and at least two sets of Y-axis detection fixed comb teeth disposed within the Y-axis detection frame. The Y-axis detection frame is connected to the second mass block through a second vibrating elastic element. The Y-axis detection moving comb teeth are connected to the Y-axis detection frame, and the Y-axis detection fixed comb teeth are fixed to the substrate through anchor points.

6. The MEMS triaxial sensor as described in claim 5, characterized in that: When the second mass block vibrates along the Y-axis, the capacitance value between at least one set of Y-axis fixed detection comb teeth and the corresponding Y-axis moving detection comb teeth increases, while the capacitance value between at least one set of Y-axis fixed detection comb teeth and the corresponding Y-axis moving detection comb teeth decreases.

7. The MEMS triaxial sensor as described in claim 2, 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 MEMS triaxial 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 MEMS triaxial sensor as described in claim 7, characterized in that: The X-axis detection capacitor assembly and the Y-axis detection capacitor assembly are located at the center of the first mass block and the second mass block, respectively. There are two first plates, which are respectively disposed at both ends of the X-axis detection capacitor assembly along the X-axis direction. There are two second plates, which are respectively disposed at both ends of the Y-axis detection capacitor assembly along the X-axis direction.

10. The MEMS triaxial sensor as described in any one of claims 1-9, characterized in that: The first mass block has a hollow structure.

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