MEMS inertial biaxial sensor

Abstract

The invention provides an MEMS inertial biaxial sensor, which comprises a sensitive mass block, a plurality of first direction detection modules and a plurality of second direction detection modules, and is characterized in that the plurality of first direction detection modules are symmetrically distributed at two ends of the sensitive mass block along a first direction and are connected with the sensitive mass block through a first direction vibration transmission beam, and the plurality of second direction detection modules are symmetrically distributed at two ends of the sensitive mass block along a second direction; the second direction detection modules are symmetrically distributed at the two ends of the sensitive mass block in the second direction and connected with the sensitive mass block through vibration decoupling elastic assemblies, and the adjacent second direction detection modules are connected through truss assemblies. An integrated structural form is adopted, and the first direction detection module and the second direction detection module are symmetrically arranged on the two sides of the sensitive mass block, so that differential capacitance is formed during vibration, a capacitance detection signal is increased, a common-mode error signal is subtracted from difference, and the capacitance signal detection sensitivity is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of inertial sensors, and in particular relates to a MEMS inertial dual-axis sensor. Background Art

[0002] Inertial sensors include accelerometers, gyroscopes, and their single-, dual-, and three-axis combinations. Accelerometers are used to detect the acceleration signals of objects in the three independent axes of the carrier coordinate system, and 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 objects in three-dimensional space, they can accurately characterize the posture of the object and have very important application value in navigation.

[0003] Existing dual-axis sensors are generally composed of two discrete single-axis sensors. However, the overall area of ​​this discrete combination of dual-axis sensors is large, and the space utilization rate is not high, which is not conducive to cost savings and miniaturization of integrated systems. In addition, there are process deviations between the discrete combination of dual-axis sensors, and the performance consistency between the two independent devices is difficult to ensure. Summary of the invention

[0004] The purpose of the present invention is to provide a MEMS inertial dual-axis sensor, which can at least solve some of the defects in the prior art.

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

[0006] A MEMS inertial dual-axis sensor comprises a sensitive mass block, a plurality of first direction detection modules and a plurality of second direction detection modules, wherein the plurality of first direction detection modules are symmetrically distributed at both ends of the sensitive mass block along a first direction and are connected to the sensitive mass block via a first direction vibration transfer beam, and the plurality of second direction detection modules are symmetrically distributed at both ends of the sensitive mass block along a second direction and are connected to the sensitive mass block via a vibration decoupling elastic component, and adjacent second direction detection modules are connected via a truss component.

[0007] Furthermore, the first direction detection module includes a first direction detection frame and at least one group of first movable comb teeth and at least one group of first fixed comb teeth arranged in the first direction detection frame; the first direction detection frame is connected to the sensitive mass block through a first direction vibration transfer beam.

[0008] Furthermore, the extending directions of the groups of first movable comb teeth in the first direction detection frame are the same, and the extending directions of the first movable comb teeth on both sides of the sensitive mass block are opposite.

[0009] Furthermore, a first-direction vibration elastic member that can be stretched and retracted along the first direction is connected to a side of the first-direction detection frame away from the sensitive mass block.

[0010] Furthermore, the second direction detection module includes a second direction detection frame, and at least one group of second movable comb teeth and at least one group of second fixed comb teeth arranged in the second direction detection frame; the second direction detection frame is connected to the sensitive mass block through a vibration decoupling elastic component.

[0011] Furthermore, when the sensitive mass block vibrates along the second direction, the truss assembly connects the adjacent second direction detection modules to perform reverse movement.

[0012] Furthermore, a second direction vibration elastic member that can be stretched and retracted along the first direction is connected to a side edge of the second direction detection frame.

[0013] Furthermore, the truss assembly includes a V-shaped truss and a second-direction vibration transmission straight beam, one end of the second-direction vibration transmission straight beam is connected to the vertex of the V-shaped truss, and the other end is connected to the sensitive mass block through the vibration decoupling elastic component, and the two ends of the V-shaped truss are respectively connected to adjacent second-direction detection modules.

[0014] Furthermore, the vibration decoupling elastic component includes a vibration decoupling straight beam and a U-shaped beam, both ends of the U-shaped beam are connected to the sensitive mass block, and the bottom center of the U-shaped beam is connected to the center of the vibration decoupling straight beam through a connecting beam.

[0015] Furthermore, the sensitive mass block is an H-shaped structure, and the vibration decoupling elastic component is located in a groove of the H-shaped structure.

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

[0017] The MEMS inertial dual-axis sensor provided by the present invention adopts an integrated structure, which reduces the device area and the overall package size. At the same time, the process deviation between different axes of the MEMS inertial dual-axis sensor is small, and the performance consistency between the two sensitive axes is high;

[0018] Furthermore, the first direction detection module and the second direction detection module are symmetrically arranged on both sides of the sensitive mass block, so that differential capacitance is formed when it vibrates, thereby increasing the capacitance detection signal and differentially subtracting the common mode error signal, thereby improving the capacitance signal detection sensitivity.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the MEMS inertial dual-axis sensor of the present invention;

[0021] Figure 2 It is a schematic diagram of the vibration of the sensitive mass block of the MEMS inertial dual-axis sensor of the present invention along the first direction;

[0022] Figure 3 It is a schematic diagram of the vibration of the sensitive mass block of the MEMS inertial dual-axis sensor of the present invention along the second direction.

[0023] Explanation of the accompanying drawings: 1. First direction detection module; 2. Second direction detection module; 3. Sensitive mass block; 4. Truss assembly; 5. Vibration decoupling elastic assembly; 6. First direction vibration transfer beam; 7. First direction detection frame; 8. First movable comb teeth; 9. First fixed comb teeth; 10. First direction vibration elastic member; 11. Second direction vibration elastic member; 12. Second direction detection frame; 13. Second movable comb teeth; 14. Second fixed comb teeth; 15. V-shaped truss; 16. Second direction vibration transfer straight beam; 17. Connecting beam; 18. U-shaped beam; 19. Vibration decoupling straight beam. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0028] like Figure 1, Figure 2 and Figure 3 As shown, this embodiment provides a MEMS inertial dual-axis sensor, including a sensitive mass block 3, a plurality of first direction detection modules 1 and a plurality of second direction detection modules 2, wherein the first direction detection modules 1 are symmetrically distributed at both ends of the sensitive mass block along the first direction, and are connected to the sensitive mass block 3 through a first direction vibration transfer beam 6, and the second direction detection modules 2 are symmetrically distributed at both ends of the sensitive mass block 3 along the second direction, and are connected to the sensitive mass block 3 through a vibration decoupling elastic component 5, and adjacent second direction detection modules 2 are connected through a truss component 4.

[0029] In some embodiments, there are two first direction detection modules 1, which are symmetrically distributed at both ends of the sensitive mass block 3 along the first direction, and the two first direction detection modules 1 are connected to the sensitive mass block 3 through the first direction vibration transmission beam 6. When the sensitive mass block 3 moves along the first direction, the two first direction detection modules 1 on both sides of the sensitive mass block 3 are driven to move synchronously through the first direction vibration transmission beam 6; there are four second direction detection modules 2, which are grouped in pairs and symmetrically distributed at both ends of the sensitive mass block 3 along the second direction, and the two second direction detection modules 2 at the same end are connected through a truss component 4, and the four second direction detection modules 2 are connected to the sensitive mass block 3 through a vibration decoupling elastic component 5. When the sensitive mass block 3 moves along the second direction, the four second direction detection modules 2 are driven to move synchronously through the truss component 4 and the vibration decoupling elastic component 5. Wherein, the above-mentioned first direction is Figure 1 The left and right direction of the sensitive mass block 3 is shown, and the second direction is Figure 1 The up and down direction of the sensitive mass block 3 is shown. The MEMS inertial dual-axis sensor provided in this embodiment adopts an integrated structure, which reduces the device area and the overall package size. At the same time, the process deviation between different axes of the MEMS inertial dual-axis sensor is small, and the performance consistency between the two sensitive axes is high.

[0030] As a specific implementation, the first direction detection module 1 includes a first direction detection frame 7 and at least one group of first movable comb teeth 8 and at least one group of first fixed comb teeth 9 arranged in the first direction detection frame 7; the first movable comb teeth 8 and the first fixed comb teeth 9 correspond to each other one by one, the first fixed comb teeth 9 are anchored on a substrate (not shown in the figure) through an anchor point, the first movable comb teeth 8 are connected to the first direction detection frame 7, and the first direction detection frame 7 is connected to the sensitive mass block 3 through a first direction vibration transmission beam 6. When the sensitive mass block 3 of the MEMS inertial dual-axis sensor vibrates along the first direction, as shown in FIG. Figure 2As shown, a variable capacitor is formed between the first movable comb teeth 8 and the corresponding first fixed comb teeth 9. Since the first movable comb teeth 8 and the first fixed comb teeth 9 of the two first direction detection modules 1 on the left and right sides of the sensitive mass block 3 are symmetrically distributed about the sensitive mass block 3, the capacitance values ​​on the left and right sides of the sensitive mass block 3 increase and decrease respectively, and the capacitances on both sides are differentiated to form a differential capacitance, which increases the capacitance detection signal, thereby improving the capacitance signal detection sensitivity, and at the same time, the common mode error signal is differentially subtracted.

[0031] Preferably, a first direction vibration elastic member 10 is connected to the first direction detection frame 7 on the side away from the sensitive mass block 3, and the first direction vibration elastic member 10 can be extended and retracted along the first direction, for example, a vibration spring, a retractable and bendable U-shaped beam, etc. The first direction vibration elastic member 10 is provided to further ensure the stability of the first direction detection frame 7 moving along the first direction.

[0032] Specifically, the groups of first movable comb teeth 8 in the first direction detection frame 7 extend in the same direction, thereby ensuring that when the sensitive mass block 3 vibrates along the first direction, the capacitance changes on the same side thereof are the same, thereby increasing the capacitance detection signal.

[0033] As a specific implementation, the second direction detection module 2 includes a second direction detection frame 12, and at least one group of second movable comb teeth 13 and at least one group of second fixed comb teeth 14 arranged in the second direction detection frame 12; the second movable comb teeth 13 and the second fixed comb teeth 14 correspond to each other one by one, the second fixed comb teeth 14 are anchored on the substrate through anchor points, the second movable comb teeth 13 are connected to the second direction detection frame 12, and the second direction detection frame 12 is connected to the sensitive mass block 3 through a vibration decoupling elastic component 5; and the second direction detection frames 12 of the two second direction detection modules 2 located at the same end of the sensitive mass block 3 along the second direction are connected through a truss component 4. When the sensitive mass block 3 of the MEMS inertial dual-axis sensor vibrates along the second direction, as Figure 3 As shown, due to the arrangement of the truss assembly 4 in the second direction, the second movable comb teeth 13 on the two second direction detection frames 12 connected by the truss assembly 4 move in the opposite direction, for example Figure 3 When the sensitive mass block 3 shown moves upward, the truss assembly 4 above it contracts and drives the two second direction detection frames 12 connected thereto to move in the opposite direction and approach each other. At the same time, the truss assembly 4 below the sensitive mass block 3 extends and pushes the two second direction detection frames 12 connected thereto to move in the opposite direction and away from each other. During this movement, a variable capacitor is formed between the second movable comb teeth 13 and the second fixed comb teeth 14. Since the left and right second direction detection modules 2 connected to the same truss assembly 4 are symmetrically distributed, the capacitance values ​​at the left and right ends increase and decrease respectively, and the difference between the capacitances at the two ends forms a differential capacitance, thereby increasing the capacitance detection signal and at the same time subtracting the common mode error signal by difference.

[0034] Preferably, the second direction detection frame 12 is connected to a second direction vibration elastic member 11 on its side. Since the movement direction of the second direction detection module 2 is along the first direction, the second direction vibration elastic member 11 is also retracted along the first direction. One end of the second direction vibration elastic member 11 is anchored on the base, and the other end is connected to the second direction detection frame 12 of the second direction detection module 2. The second direction vibration elastic member 11 can be, but is not limited to, a vibration spring, a retractable and bendable U-shaped beam, etc. The second direction vibration elastic member 11 is provided to further ensure the stability of the second direction detection frame 12 moving along the first direction.

[0035] Specifically, the extension directions of the groups of second movable comb teeth 13 in the second direction detection frame 12 are the same, so as to ensure that when the sensitive mass block 3 vibrates along the second direction, the capacitance changes on the same second direction detection frame 12 are the same, thereby increasing the capacitance detection signal.

[0036] As a specific implementation, the truss assembly 4 includes a V-shaped truss 15 and a second direction vibration transmission straight beam 16, one end of the second direction vibration transmission straight beam 16 is connected to the vertex of the V-shaped truss 15, the other end of the second direction vibration transmission straight beam 16 is connected to the sensitive mass block 3 through the vibration decoupling elastic assembly 5, and the two ends of the V-shaped truss 15 are respectively connected to two second direction detection modules 2. Among them, the V-shaped truss 15 and the second direction vibration transmission straight beam 16 can be stretched, bent and deformed when subjected to a force. When the sensitive mass block 3 moves along the second direction, the second direction vibration transmission straight beam 16 of the truss assembly 4 at one end thereof pushes the vertex of the V-shaped truss 15, so that the two free ends of the V-shaped truss 15 are close to each other, driving the two second direction detection modules 2 connected thereto to move in the opposite direction; at the same time, the second direction vibration transmission straight beam 16 of the truss assembly 4 at the other end pulls the vertex of the V-shaped truss 15, so that the two free ends of the V-shaped truss 15 are away from each other, and also drives the two second direction detection modules 2 connected thereto to move in the opposite direction.

[0037] As a specific implementation, the vibration decoupling elastic component 5 includes a vibration decoupling straight beam 19 and a U-shaped beam 18. The vibration decoupling straight beam 19 is located between the sensitive mass block 3 and the second direction detection module 2. Both ends of the vibration decoupling straight beam 19 are anchored on the base. The opening of the U-shaped beam 18 faces the vibration decoupling straight beam 19. Both ends of the U-shaped beam 18 are connected to the sensitive mass block 3. The bottom center of the U-shaped beam 18 is connected to the center of the vibration decoupling straight beam 19 through a connecting beam 17. At the same time, the end of the second direction vibration transmission straight beam 16 of the truss component 4 is connected to the center of the vibration decoupling straight beam 19. Wherein, the vibration decoupling straight beam 19 and the U-shaped beam 18 can be stretched, bent and deformed when subjected to force. When the sensitive mass block 3 vibrates along the first direction, the first direction detection module 1 moves along the first direction with the sensitive mass block 3, and due to the deformation of the vibration decoupling straight beam 19 and the U-shaped beam 18, the second direction detection module 2 does not move; similarly, when the sensitive mass block 3 vibrates along the second direction, the second direction detection module 2 moves accordingly under the action of the truss assembly 4, and due to the deformation of the vibration decoupling straight beam 19 and the U-shaped beam 18, the first direction detection module 1 does not move.

[0038] Specifically, the sensitive mass block 3 is designed to be an H-shaped structure, the U-shaped beam 18 is located in the groove of the H-shaped structure, and both ends of the U-shaped beam 18 are connected to the ends of the vertical section of the H-shaped structure.

[0039] It should be noted that in the present invention, Figure 2 and Figure 3 The MEMS inertial dual-axis sensor vibrates along the first direction and the second direction respectively, and the schematic diagram of the final state of the motion of its movable component is shown. In order to reflect the motion effect, the movement displacement of the movable component in the figure is exaggerated.

[0040] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A MEMS inertial dual-axis sensor, characterized in that: The invention comprises a sensitive mass block, a plurality of first direction detection modules and a plurality of second direction detection modules. The plurality of first direction detection modules are symmetrically distributed at both ends of the sensitive mass block along the first direction and are connected to the sensitive mass block through a first direction vibration transfer beam. The plurality of second direction detection modules are symmetrically distributed at both ends of the sensitive mass block along the second direction and are connected to the sensitive mass block through a vibration decoupling elastic component. Adjacent second direction detection modules are connected through a truss component.

2. The MEMS inertial dual-axis sensor according to claim 1, characterized in that: The first direction detection module includes a first direction detection frame and at least one group of first movable comb teeth and at least one group of first fixed comb teeth arranged in the first direction detection frame; the first direction detection frame is connected to the sensitive mass block through a first direction vibration transmission beam.

3. The MEMS inertial dual-axis sensor according to claim 2, characterized in that: The extending directions of the groups of first movable comb teeth in the first direction detection frame are the same, and the extending directions of the first movable comb teeth on both sides of the sensitive mass block are opposite.

4. The MEMS inertial dual-axis sensor according to claim 2, characterized in that: A first-direction vibration elastic member that can be stretched and retracted along the first direction is connected to a side of the first-direction detection frame away from the sensitive mass block.

5. The MEMS inertial dual-axis sensor according to claim 1, characterized in that: The second direction detection module includes a second direction detection frame, and at least one group of second movable comb teeth and at least one group of second fixed comb teeth arranged in the second direction detection frame; The second direction detection frame is connected to the sensitive mass block via a vibration decoupling elastic component.

6. The MEMS inertial dual-axis sensor according to claim 5, characterized in that: When the sensitive mass block vibrates along the second direction, the truss assembly connects the adjacent second direction detection modules to perform reverse movement.

7. The MEMS inertial dual-axis sensor according to claim 5, characterized in that: A second direction vibrating elastic member which can be stretched and retracted along the first direction is connected to a side edge of the second direction detection frame.

8. The MEMS inertial dual-axis sensor according to claim 1, characterized in that: The truss assembly includes a V-shaped truss and a second-direction vibration transmission straight beam, one end of the second-direction vibration transmission straight beam is connected to the vertex of the V-shaped truss, and the other end is connected to the sensitive mass block through the vibration decoupling elastic component, and the two ends of the V-shaped truss are respectively connected to adjacent second-direction detection modules.

9. The MEMS inertial dual-axis sensor according to claim 1, characterized in that: The vibration decoupling elastic component includes a vibration decoupling straight beam and a U-shaped beam, both ends of the U-shaped beam are connected to the sensitive mass block, and the bottom center of the U-shaped beam is connected to the center of the vibration decoupling straight beam through a connecting beam.

10. The MEMS inertial dual-axis sensor according to claim 9, characterized in that: The sensitive mass block is an H-shaped structure, and the vibration decoupling elastic component is located in a groove of the H-shaped structure.

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