A MEMS accelerometer
By employing multiple sensitive structures and elastically coupled beam structures in the MEMS accelerometer, the problem of increased thermal stress in the spring beam was solved, thereby improving sensitivity and signal-to-noise ratio as well as enhancing structural stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- WUHAN HENGYONG TECH DEV CO LTD
- Filing Date
- 2025-06-26
- Publication Date
- 2026-07-10
AI Technical Summary
In traditional MEMS accelerometers, improving sensitivity and signal-to-noise ratio leads to increased thermal stress on the spring beam, affecting device performance.
Multiple sensitive structures are connected by an elastically coupled beam structure to increase the area of the mass block. The elastically coupled beams generate slight deformation when the sensitive structures move, which isolates and distributes stress and reduces the thermal stress of the spring beam.
While improving the sensitivity and signal-to-noise ratio of the MEMS accelerometer, it effectively reduces the thermal stress of the spring beam, improves structural stability, reduces noise, and enhances measurement accuracy.
Smart Images
Figure CN224480494U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of sensor technology, and in particular to a MEMS accelerometer. Background Technology
[0002] MEMS accelerometers are fabricated using micromachining techniques and can measure acceleration signals. With the development of micro inertial devices, the requirements for the signal output and signal-to-noise ratio of accelerometers are becoming increasingly stringent. Traditional single-mass MEMS accelerometers suffer from low sensitivity and low signal-to-noise ratio.
[0003] A typical accelerometer consists of a base, a sensing structure, and a spring beam. The sensing structure is mounted on the base via the spring beam. Improving the sensitivity and signal-to-noise ratio of the device is generally achieved by increasing the area of the mass block of the sensing structure. However, increasing the area of the mass block will increase the mass of the mass block, increase the inertial force, and consequently increase the thermal stress on the spring beam. Utility Model Content
[0004] The main purpose of this invention is to propose a MEMS accelerometer that aims to solve the problem that improving the sensitivity and signal-to-noise ratio of existing MEMS accelerometers can lead to increased thermal stress on the spring beam.
[0005] To achieve the above objectives, this utility model proposes a MEMS accelerometer, including a substrate and a plurality of sensitive structures disposed on the substrate. The plurality of sensitive structures are interconnected by an elastic coupling beam structure. Each sensitive structure includes a mass block and a sensitive capacitor disposed on the mass block. The mass blocks of two adjacent sensitive structures are interconnected by the elastic coupling beam structure.
[0006] According to some embodiments of the present invention, multiple sensitive structures are configured as a single-row structure.
[0007] According to some embodiments of the present invention, the plurality of the sensitive structures are configured as a multi-row structure, and the adjacent rows of the sensitive structures are electrically connected.
[0008] According to some embodiments of the present invention, the elastic coupling beam structure includes two elastic coupling beams, and the mass blocks of two adjacent sensitive structures are connected through the two elastic coupling beams.
[0009] According to some embodiments of the present invention, the two elastic coupling beams are respectively connected to the two corners of each mass block facing the adjacent mass block.
[0010] According to some embodiments of the present invention, the elastic coupling beam is U-shaped and bends toward the other elastic coupling beam.
[0011] According to some embodiments of the present invention, the elastically coupled beam structure further includes a rigid connector, the two ends of which are respectively connected to the middle of the end face of each mass block facing the other mass block.
[0012] According to some embodiments of the present invention, the elastic coupling beam structure further includes an elastic connection component, and the two elastic coupling beams are connected by the elastic connection component. The elastic connection component includes a first elastic beam, one end of which is connected to one of the elastic coupling beams, and the other end of which is connected to the other elastic coupling beam.
[0013] According to some embodiments of the present invention, there are two first elastic beams, which are spaced apart in the x-direction and both first elastic beams extend in the y-direction.
[0014] According to some embodiments of the present invention, the elastic connection assembly further includes two second elastic beams connected in a cross shape. The two second elastic beams are disposed within the space enclosed by the two elastic coupling beams and the two first elastic beams, wherein one of the second elastic beams is connected to the two elastic coupling beams respectively, and the other second elastic beam is connected to the two first elastic beams respectively.
[0015] This utility model has at least the following beneficial effects:
[0016] In this invention, by setting multiple sensitive structures to increase the mass area of the entire device, the sensitivity and signal-to-noise ratio of the MEMS accelerometer are improved. Simultaneously, an elastic coupling beam structure connects the mass blocks of adjacent sensitive structures. This elastic coupling beam structure undergoes slight deformation when the two sensitive structures move, which isolates the stress transmitted between the mass blocks of the two sensitive structures and distributes the stress transmitted by the mass blocks, thereby reducing the stress on the spring beam and avoiding localized stress concentration. This invention, by setting multiple sensitive structures and connecting the mass blocks of adjacent sensitive structures through the elastic coupling beam structure, effectively reduces the thermal stress on the spring beam while increasing the accelerometer's sensitivity and signal-to-noise ratio. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1A schematic diagram of the structure of a MEMS accelerometer provided in an embodiment of this utility model;
[0019] Figure 2 for Figure 1 A schematic diagram of the structure of the sensitive capacitor in the diagram;
[0020] Figure 3 This is a schematic diagram of the structure of the MEMS accelerometer provided in the second embodiment of the present invention;
[0021] Figure 4 This is a schematic diagram of the structure of the MEMS accelerometer provided in the third embodiment of the present invention;
[0022] Figure 5 This is a schematic diagram of the structure of the MEMS accelerometer provided in the fourth embodiment of the present invention;
[0023] Figure 6 This is a schematic diagram of the structure of the MEMS accelerometer provided in the fifth embodiment of the present invention.
[0024] Explanation of reference numerals in the attached figures:
[0025] 100 - MEMS accelerometer; 1 - substrate; 2 - sensitive structure; 21 - mass block; 22 - sensitive capacitor; 221 - fixed comb tooth; 222 - moving comb tooth; 3 - elastic coupling beam structure; 31 - elastic coupling beam; 32 - rigid connector; 33 - elastic connection assembly; 331 - first elastic beam; 332 - second elastic beam; 4 - spring beam. Detailed Implementation
[0026] The technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0027] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.
[0028] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.
[0029] This invention provides a MEMS accelerometer. Figures 1 to 6 This invention provides a specific embodiment of a MEMS accelerometer.
[0030] like Figure 1 As shown, this utility model embodiment provides a MEMS accelerometer 100, including a substrate 1 and a plurality of sensitive structures 2 disposed on the substrate 1. The plurality of sensitive structures 2 are interconnected by an elastic coupling beam structure 3. Each sensitive structure 2 includes a mass block 21 and a sensitive capacitor 22 disposed on the mass block 21. The mass blocks 21 of two adjacent sensitive structures are interconnected by the elastic coupling beam structure 3.
[0031] In this invention, by setting multiple sensitive structures 2 to increase the area of the mass block 21 of the entire device, the sensitivity and signal-to-noise ratio of the MEMS accelerometer 100 are improved. Simultaneously, an elastic coupling beam structure 3 connects the mass blocks 21 of adjacent sensitive structures 2. The elastic coupling beam structure 3 undergoes slight deformation when the two sensitive structures 2 move, which isolates the stress transmitted by the mass blocks 21 of the two sensitive structures and distributes the stress transmitted by the mass blocks 21, thereby reducing the stress on the spring beam 4 and avoiding localized stress concentration. This invention, by setting multiple sensitive structures 2 and connecting adjacent mass blocks 21 of adjacent sensitive structures 2 through the elastic coupling beam structure 3, effectively reduces the thermal stress on the spring beam 4 while increasing the accelerometer's sensitivity and signal-to-noise ratio.
[0032] It should be noted that the sensitive capacitor 22 is located in the middle of the mass block 21, and the spring beam 4 is provided on both sides of the sensitive capacitor 22 in the y direction.
[0033] To reduce measurement errors, in some embodiments, such as Figure 1As shown, the mass block 21 is provided with at least two sensitive capacitors 22, which are spaced apart in the x-direction. This arrangement allows for the measurement of multiple values using multiple sensitive capacitors 22, and the average of these values is used as the final measurement result to reduce measurement error.
[0034] Specifically, such as Figure 2 As shown, the sensitive capacitor 22 includes a fixed comb tooth 221 and two movable comb teeth 222 respectively disposed on both sides of the fixed comb tooth 221 in the x-direction. The fixed comb tooth 221 is fixed on the substrate 1, and the two movable comb teeth 222 are both connected to the mass block 21. The MEMS accelerometer 100 is a comb-type accelerometer. When the mass block 21 moves relative to the substrate 1 in the y-direction, it drives the two movable comb teeth 222 to move in the y-direction, causing a change in the distance between the movable comb teeth 222 and the plates on the fixed comb tooth 221, resulting in a change in capacitance. The detection circuit can convert the capacitance change into a voltage signal. Since the acceleration is proportional to the displacement of the mass block 21, the feedback voltage is linearly related to the acceleration, thereby achieving high-precision measurement of acceleration. Meanwhile, since the plate of the fixed comb tooth 221 is located between the two plates of the movable comb tooth 222, when the movable comb tooth 222 moves, the distance between the plate of the fixed comb tooth 221 and one of the plates of the movable comb tooth 222 decreases, while the distance between the plate and the other plate increases, causing a differential change in the capacitance of the corresponding comb tooth, thereby canceling out common-mode noise. Since the comb-type sensitive capacitor 22 is existing technology, the specific principle derivation will not be elaborated further.
[0035] The arrangement of the plurality of sensitive structures 2 is not limited; for example, in some embodiments, such as... Figure 1 As shown, the multiple sensitive structures 2 are configured as a single-row structure. When the multiple sensitive structures 2 are configured as a single-row structure, the mass blocks 21 of two adjacent sensitive structures 2 are connected to each other through the elastic coupling beam structure 2.
[0036] In some embodiments, such as Figure 3 As shown, the plurality of sensitive structures 2 are configured in a multi-row structure, with adjacent rows of sensitive structures 2 electrically connected. Specifically, the fixed comb teeth 221 of the sensitive capacitors 22 in adjacent rows of sensitive structures 2 are all electrically connected to the differential circuit, and the fixed comb teeth 221 in the two rows of sensitive structures 2 are respectively set to correspond to the positive and negative input terminals of the differential circuit. That is, the fixed comb teeth 221 in the two rows of sensitive structures 2 are respectively connected to the positive and negative input terminals of the differential amplifier, so that the capacitance values of the two sensitive capacitors 22 change in opposite directions to form complementary outputs. Therefore, the sensitive capacitors 22 on the two rows of sensitive structures 2 further achieve the effect of noise reduction through two-stage differential circuitry.
[0037] The specific structure of the elastic coupling beam structure 3 is not limited, as long as it ensures that the mass blocks 21 of two adjacent sensitive structures 2 are interconnected through the elastic coupling beam structure 3. In some embodiments, such as... Figure 1 As shown, the elastic coupling beam structure 3 includes two elastic coupling beams 31, and the mass blocks 21 of two adjacent sensitive structures 2 are connected by the two elastic coupling beams 31. With this configuration, when each mass block 21 experiences a slight displacement during movement, the stress transmitted by the mass block 21 can be shared by the deformation of the two elastic coupling beams, thereby reducing the stress on the spring beam 4 and avoiding local stress concentration.
[0038] In some embodiments, such as Figure 1 As shown, the two elastic coupling beams 31 are respectively connected to the two corners of each mass block 21 facing the adjacent mass block 21. Since the offset is greatest at the two corners when the mass blocks 21 experience slight displacement during movement, connecting the two elastic coupling beams 31 at the two corners reduces the offset, thereby improving the structural stability of the sensitive structure 2. Specifically, the two elastic coupling beams 31 are symmetrically arranged in the y-direction, and the two elastic coupling beams 31 have the same shape, ensuring that the overall stiffness of the sensitive structure 2 is consistent when it reciprocates in the y-direction.
[0039] Furthermore, in some embodiments, such as Figure 1 As shown, the elastic coupling beam 31 is U-shaped and bends towards the other elastic coupling beam 31. This arrangement increases the length of the elastic coupling beam 31, extending the stress transmission path between the two adjacent mass blocks 21, thereby improving the stress isolation effect of the elastic coupling beam 31.
[0040] Furthermore, in some embodiments, such as Figure 1 As shown, the elastically coupled beam structure 3 also includes a rigid connector 32, the two ends of which are respectively connected to the middle of the end face of each mass block 21 facing the other mass block 21. This configuration ensures synchronous movement of the two mass blocks 21 through the rigid connector 32, and also ensures that the offset at both ends is consistent when a slight offset occurs during the reciprocating movement of each mass block 21 in the y-direction, thereby improving the structural stability of the sensitive structure 2.
[0041] Furthermore, in some embodiments, such as Figure 1 As shown, the rigid connector 32 is arranged in a ring shape. This arrangement, through the hollow design of the rigid connector 32, reduces the connection strength between the two mass blocks 21, allowing the rigid connector 32 to undergo slight deformation to share some of the stress, thereby reducing the stress on the spring beam 4.
[0042] In some embodiments, such as Figure 4 As shown, the elastic coupling beam structure 3 further includes an elastic connection component 33, through which the two elastic coupling beams 31 are connected. The elastic connection component 33 includes a first elastic beam 331, one end of which is connected to one of the elastic coupling beams 31, and the other end of which is connected to the other elastic coupling beam 31. With this configuration, when each of the mass blocks 21 moves relative to the base 1 in the y-direction, the first elastic beam 331 undergoes slight expansion and contraction in the y-direction to share some of the stress transmitted from the mass blocks 21 through the elastic coupling beam 31, thereby reducing the stress on the spring beam 4.
[0043] Furthermore, in some embodiments, such as Figure 5 As shown, there are two first elastic beams 331, which are spaced apart in the x-direction and both extend along the y-direction. This arrangement increases the number of second elastic beams 332 to distribute more stress, thereby reducing the stress on the spring beam 4.
[0044] Furthermore, in some embodiments, such as Figure 6 As shown, the elastic connection component 33 further includes two second elastic beams 332 connected in a cross shape. The two second elastic beams 332 are disposed within the space enclosed by the two elastic coupling beams 31 and the two first elastic beams 331. One second elastic beam 332 is connected to each of the two elastic coupling beams 31, and the other second elastic beam 332 is connected to each of the two first elastic beams 331. This arrangement, by adding second elastic beams 332 within the space enclosed by the elastic coupling beams 31 and the first elastic beams 331, allows the elastic connection component 33 to distribute more stress. Furthermore, by increasing the connection points between the two elastic coupling beams 31, the two elastic coupling beams 31 form a whole, reducing the deformation of each elastic coupling beam 31 when the mass block 21 moves, thereby reducing the offset between adjacent mass blocks 21 during movement.
[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A MEMS accelerometer, characterized in that, The system includes a substrate and multiple sensitive structures disposed on the substrate. The multiple sensitive structures are interconnected by an elastic coupling beam structure. Each sensitive structure includes a mass block and a sensitive capacitor disposed on the mass block. The mass blocks of two adjacent sensitive structures are interconnected by the elastic coupling beam structure.
2. The MEMS accelerometer as described in claim 1, characterized in that, Multiple of the aforementioned sensitive structures are configured as a single-row structure.
3. The MEMS accelerometer as described in claim 1, characterized in that, The multiple sensitive structures are configured in a multi-row structure, and adjacent rows of the sensitive structures are electrically connected.
4. The MEMS accelerometer as described in claim 1, characterized in that, The elastically coupled beam structure includes two elastically coupled beams, and the mass blocks of two adjacent sensitive structures are connected by the two elastically coupled beams.
5. The MEMS accelerometer as described in claim 4, characterized in that, The two elastic coupling beams are respectively connected to the two corners of each mass block facing the adjacent mass block.
6. The MEMS accelerometer as described in claim 4, characterized in that, The elastic coupling beam is U-shaped and bends toward the other elastic coupling beam.
7. The MEMS accelerometer as described in claim 4, characterized in that, The elastically coupled beam structure also includes a rigid connector, the two ends of which are respectively connected to the middle of the end face of each mass block facing the other mass block.
8. The MEMS accelerometer as described in claim 4, characterized in that, The elastic coupling beam structure further includes an elastic connection component, through which the two elastic coupling beams are connected. The elastic connection component includes a first elastic beam, one end of which is connected to one of the elastic coupling beams, and the other end of which is connected to the other elastic coupling beam.
9. The MEMS accelerometer as described in claim 8, characterized in that, There are two first elastic beams, which are spaced apart in the x-direction and both extend in the y-direction.
10. The MEMS accelerometer as described in claim 9, characterized in that, The elastic connection assembly further includes two second elastic beams connected in a cross shape. The two second elastic beams are disposed within the space enclosed by the two elastic coupling beams and the two first elastic beams. One of the second elastic beams is connected to the two elastic coupling beams respectively, and the other second elastic beam is connected to the two first elastic beams respectively.