CN221238973U - Triaxial capacitive MEMS accelerometer - Google Patents
Triaxial capacitive MEMS accelerometer Download PDFInfo
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- CN221238973U CN221238973U CN202323262914.9U CN202323262914U CN221238973U CN 221238973 U CN221238973 U CN 221238973U CN 202323262914 U CN202323262914 U CN 202323262914U CN 221238973 U CN221238973 U CN 221238973U
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 41
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 41
- 239000010703 silicon Substances 0.000 claims abstract description 41
- 239000000758 substrate Substances 0.000 claims abstract description 41
- 239000003990 capacitor Substances 0.000 claims description 19
- 238000005530 etching Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 230000001133 acceleration Effects 0.000 description 8
- 238000006073 displacement reaction Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
Abstract
The utility model discloses a triaxial capacitive MEMS accelerometer, which comprises an XY-axis accelerometer mass block, an XY-axis accelerometer spring system, a Z-axis mass block, a Z-axis accelerometer spring system and a silicon substrate. According to the utility model, the mass block of the XY-axis accelerometer, the mass block of the Z-axis accelerometer and the silicon substrate are sequentially nested and designed in the same plane from inside to outside, the mass block of the XY-axis accelerometer, the mass block of the Z-axis accelerometer and the silicon substrate are connected through a spring system, and the XY-axis MEMS accelerometer and the Z-axis MEMS accelerometer are manufactured in the single plane, so that the manufacturing is simple and the cost is low; and the design structure has the advantages that the measurable capacitance value is larger, the mass block is larger and the noise is lower under the same area.
Description
Technical Field
The utility model relates to an accelerometer, in particular to a triaxial capacitive MEMS accelerometer, and belongs to the technical field of inertial sensors.
Background
MEMS capacitive accelerometers are an inertial sensor that senses the acceleration of a measured object. The device has the advantages of small volume, low cost, suitability for mass production and the like, and is widely applied to the fields of consumer electronics, automobile industry, aerospace and the like. In the prior art, in order to realize triaxial acceleration measurement, three uniaxial accelerometers need to be packaged, and during production, a Z-axis MEMS accelerometer and an XY-axis MEMS accelerometer are manufactured independently, and then the Z-axis MEMS accelerometer and the XY-axis MEMS accelerometer are packaged in a combined mode. The production and the manufacture are complicated, the production procedures are more, and the cost is higher.
Disclosure of utility model
The technical problem to be solved by the utility model is to provide the triaxial capacitive MEMS accelerometer, which is characterized in that the XY axis MEMS accelerometer and the Z axis MEMS accelerometer are manufactured in a single plane, and the manufacturing is simple and the cost is low.
In order to solve the technical problems, the utility model adopts the following technical scheme:
The three-axis capacitive MEMS accelerometer comprises an XY-axis accelerometer mass block, an XY-axis accelerometer spring system, a Z-axis mass block, a Z-axis accelerometer spring system and a silicon substrate, wherein the XY-axis accelerometer mass block is arranged on the inner side of the Z-axis mass block and connected with the Z-axis mass block through the XY-axis accelerometer spring system, the Z-axis mass block is arranged on the inner side of the silicon substrate and connected with the silicon substrate through the Z-axis accelerometer spring system, an X-axis movable capacitor plate arranged along the Y-axis direction is arranged on the XY-axis accelerometer mass block, an X-axis fixed capacitor plate corresponding to the X-axis movable capacitor plate is arranged on the Z-axis accelerometer mass block, a Y-axis fixed capacitor plate corresponding to the Y-axis movable capacitor plate is arranged on the XY-axis accelerometer mass block, a Z-axis movable capacitor plate is arranged on the outer side of the Z-axis mass block, a Z-axis movable capacitor plate is arranged at the bottom of the Z-axis mass block, and a Z-axis fixed capacitor plate corresponding to the Z-axis movable capacitor plate is arranged at the bottom of the silicon substrate.
Further, the mass block of the XY-axis accelerometer is a square mass block, the Z-axis mass block is also a square mass block, a square hole is formed in the center of the Z-axis mass block and is larger than the mass block of the XY-axis accelerometer, and the silicon substrate is a square frame body and is arranged on the outer side of the Z-axis mass block.
Further, the XY-axis accelerometer spring system comprises four groups of plane springs, each group of plane springs is coiled in an S-shaped mode in the XY plane and integrally coiled into an L-shaped mode with two symmetrical sides, one end of each plane spring is connected with one corner outer side of the XY-axis accelerometer mass block, and the other end of each plane spring is connected with one corner inner side of a square hole in the Z-axis mass block.
Further, the Z-axis accelerometer spring system comprises four cantilever beams, wherein each cantilever beam is perpendicular to one side edge of the silicon substrate and is positioned at the midpoint of the side edge of the silicon substrate.
Further, a groove which is vertical to the side edges of the Z-axis mass block and is inward is formed in the middle point of the four side edges of the Z-axis mass block, the groove width of the groove is larger than that of the cantilever beam, one end of the cantilever beam is fixed on the inner side of the side edge of the silicon substrate, and the other end of the cantilever beam is fixed at the bottom of the groove.
Further, at least two groups of X-axis movable capacitance plates and X-axis fixed capacitance plates are arranged in front of the XY-axis accelerometer mass block and the Z-axis mass block, and the two groups of X-axis movable capacitance plates and the X-axis fixed capacitance plates are symmetrically arranged on two sides of the XY-axis accelerometer mass block in the Y-axis direction.
Further, at least two groups of Y-axis movable capacitance plates and Y-axis fixed capacitance plates are arranged in front of the XY-axis accelerometer mass block and the Z-axis mass block, and the two groups of Y-axis movable capacitance plates and the Y-axis fixed capacitance plates are symmetrically arranged on two sides of the XY-axis accelerometer mass block in the X-axis direction.
Further, the XY-axis accelerometer mass block, the XY-axis accelerometer spring system, the Z-axis mass block and the Z-axis accelerometer spring system are processed by an etching process and are suspended on a silicon substrate.
Compared with the prior art, the utility model has the following advantages and effects: according to the triaxial capacitive MEMS accelerometer, the XY axis accelerometer mass block, the Z axis mass block and the silicon substrate are sequentially nested and designed in the same plane from inside to outside, the XY axis accelerometer mass block, the Z axis mass block and the silicon substrate are connected through the spring system, and the XY axis MEMS accelerometer and the Z axis MEMS accelerometer are manufactured in the single plane, so that the manufacturing is simple and the cost is low; and the design structure has the advantages that the measurable capacitance value is larger, the mass block is larger and the noise is lower under the same area.
Drawings
FIG. 1 is a schematic diagram of a three-axis capacitive MEMS accelerometer of the utility model.
FIG. 2 is a partial schematic view of a triaxial capacitive MEMS accelerometer of the present utility model.
Detailed Description
In order to explain in detail the technical solutions adopted by the present utility model to achieve the predetermined technical purposes, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are only some embodiments of the present utility model, but not all embodiments, and that technical means or technical features in the embodiments of the present utility model may be replaced without inventive effort, and the present utility model will be described in detail below with reference to the accompanying drawings in combination with the embodiments.
As shown in fig. 1, a three-axis capacitive MEMS accelerometer of the utility model comprises an XY-axis accelerometer mass 100, an XY-axis accelerometer spring system 110, a Z-axis mass 200, a Z-axis accelerometer spring system 210, and a silicon substrate 300. The XY-axis accelerometer mass 100 is arranged inside the Z-axis accelerometer mass 200 and the XY-axis accelerometer mass 100 is connected with the Z-axis accelerometer mass 200 through the XY-axis accelerometer spring system 110, the Z-axis accelerometer mass 200 is arranged inside the silicon substrate 300 and the Z-axis accelerometer mass 200 is connected with the silicon substrate 300 through the Z-axis accelerometer spring system 210, the XY-axis accelerometer mass 100 is provided with an X-axis movable capacitance piece 112 arranged along the Y-axis direction, the Z-axis accelerometer mass 100 is provided with an X-axis fixed capacitance piece 111 corresponding to the position of the X-axis movable capacitance piece 112, the XY-axis accelerometer mass 100 is provided with a Y-axis movable capacitance piece 122 arranged along the X-axis direction, the Z-axis accelerometer mass 200 is provided with a Y-axis fixed capacitance piece 121 corresponding to the position of the Y-axis movable capacitance piece 122, the bottom of the Z-axis accelerometer mass 200 is provided with a Z-axis movable capacitance piece 212, and the silicon substrate 300 is provided with a Z-axis fixed capacitance piece 211 corresponding to the Z-axis movable capacitance piece 212
The XY-axis accelerometer mass block 100 is a square mass block, the Z-axis mass block 200 is also a square mass block, a square hole is formed in the center of the Z-axis mass block 200 and is larger than the XY-axis accelerometer mass block 100, and the XY-axis accelerometer mass block 100 is located at the center of the square hole in the center of the Z-axis mass block 200. The silicon substrate 300 is a square frame and is disposed outside the Z-axis proof mass 200, and the Z-axis proof mass 200 is also located at the very center of the silicon substrate 300.
The XY-axis accelerometer spring system 110 comprises four groups of planar springs, each group of planar springs is coiled in an S-shape in the XY plane and integrally coiled into an L-shape with two symmetrical sides, one end of each planar spring is connected with one corner outside of the XY-axis accelerometer mass block 100, and the other end of each planar spring is connected with one corner inside of a square hole in the Z-axis mass block 200. The connected L-shaped planar springs just fill the corners of the gap between the XY-axis accelerometer mass 100 and the Z-axis mass 200. The positioning at the four corners can balance the movement of the XY-axis accelerometer mass 100 within the Z-axis mass 200.
The Z-axis accelerometer spring system 210 includes four cantilevered beams, each of which is disposed perpendicular to one side of the silicon substrate 300 and at a midpoint of the side of the silicon substrate 300. The middle points of the four sides of the Z-axis mass block 200 are provided with a groove which is perpendicular to the inward sides of the Z-axis mass block 200, the groove width of the groove is larger than that of the cantilever beam, one end of the cantilever beam is fixed on the inner side of the silicon substrate 300, and the other end of the cantilever beam is fixed at the bottom of the groove. Through the groove structure design, the length of the cantilever beam can be better, so that the Z-axis mass block 200 can conveniently lift along the Z axis. And divide into four relatively independent areas with Z axle quality piece 200 through the groove structure, every regional independent electric capacity structure that sets up, gather four sets of data and handle the back, can obtain more accurate acceleration value.
At least two sets of X-axis movable capacitance pieces 112 and X-axis fixed capacitance pieces 111 are provided before the XY-axis accelerometer mass 100 and the Z-axis mass 200, and the two sets of X-axis movable capacitance pieces 112 and X-axis fixed capacitance pieces 111 are symmetrically provided on both sides of the XY-axis accelerometer mass 10 in the Y-axis direction. At least two groups of Y-axis movable capacitance pieces 122 and Y-axis fixed capacitance pieces 121 are arranged in front of the XY-axis accelerometer mass block 100 and the Z-axis mass block 200, and the two groups of Y-axis movable capacitance pieces 122 and Y-axis fixed capacitance pieces 121 are symmetrically arranged on two sides of the XY-axis accelerometer mass block 100 in the X-axis direction. Increasing the number of groups of the X-axis movable capacitance piece 112 and the X-axis fixed capacitance piece 111 and the Y-axis movable capacitance piece 122 and the Y-axis fixed capacitance piece 121 can increase the sensing capacitance. The electrodes of the X-axis movable capacitive plate 112 may be drawn through the X-axis movable capacitive plate 112, the XY-axis accelerometer mass 100, the XY-axis accelerometer spring system 110, the Z-axis mass 200, the Z-axis accelerometer spring system 210, and the silicon substrate 300 in that order. The electrodes of the X-axis fixed capacitance sheet 111 may be led out through the X-axis fixed capacitance sheet 111, the Z-axis mass 200, the Z-axis accelerometer spring system 210, and the silicon substrate 300 in order. The motor leading-out mode of the capacitor plate of the Y axis is the same as that of the X axis, so that the description is omitted. The electrodes of the Z-axis movable capacitive plate 212 may be drawn through the Z-axis movable capacitive plate 212, the Z-axis proof mass 200, the Z-axis accelerometer spring system 210, and the silicon substrate 300. The electrode of the Z-axis fixed capacitance piece 211 may be drawn through the Z-axis fixed capacitance piece 211 and the silicon substrate 300.
The XY-axis accelerometer mass 100, XY-axis accelerometer spring system 110, Z-axis mass 200, and Z-axis accelerometer spring system 210 are fabricated using an etching process and suspended on a silicon substrate 300. The etching depth of the silicon substrate in the Z-axis direction can be increased by increasing the size of the gap between the Z-axis proof mass 200 and the silicon substrate 300, the gap between the Z-axis proof mass 200 recess and the cantilever beam of the Z-axis accelerometer spring system 210, and the gap between the inner side of the square hole of the Z-axis proof mass 200 and the outermost side of the XY-axis accelerometer spring system 110, and by increasing the etching through hole on the XY-axis accelerometer proof mass 100.
The working principle of the triaxial capacitive MEMS accelerometer of the utility model is as follows: when the X-axis direction receives the acceleration ax, the XY-axis accelerometer mass 100 overcomes the elasticity of the XY-axis accelerometer spring system 110 and generates dx displacement along the X-axis, so that the X-axis movable capacitance piece 112 generates dx displacement, the distance between the X-axis movable capacitance piece 112 and the X-axis fixed capacitance piece 112 becomes smaller, the formed capacitance increases dC, and the sensing circuit detects dC to calculate the X-axis acceleration ax. The same principle of Y-axis acceleration detection is the same as that of X-axis. When the Z direction is subjected to acceleration az, the Z-axis mass 200 overcomes the elasticity of the Z-axis accelerometer spring system 210 and increases dz displacement downwards, the distance between the Z-axis movable capacitance piece 212 and the Z-axis fixed capacitance piece 211 is reduced, the formed capacitance increases dC, and the sensing circuit detects dC to calculate the acceleration az.
According to the triaxial capacitive MEMS accelerometer, the XY axis accelerometer mass block, the Z axis mass block and the silicon substrate are sequentially nested and designed in the same plane from inside to outside, the XY axis accelerometer mass block, the Z axis mass block and the silicon substrate are connected through the spring system, and the XY axis MEMS accelerometer and the Z axis MEMS accelerometer are manufactured in the single plane, so that the manufacturing is simple and the cost is low; and the design structure has the advantages that the measurable capacitance value is larger, the mass block is larger and the noise is lower under the same area.
The present utility model is not limited to the preferred embodiments, but is capable of modification and variation in detail, and other embodiments, such as those described above, of making various modifications and equivalents will fall within the spirit and scope of the present utility model.
Claims (8)
1. A triaxial capacitive MEMS accelerometer, characterized in that: the X-axis and Y-axis accelerometer mass block comprises an XY-axis accelerometer mass block, an XY-axis accelerometer spring system, a Z-axis mass block, a Z-axis accelerometer spring system and a silicon substrate, wherein the XY-axis accelerometer mass block is arranged on the inner side of the Z-axis mass block and is connected with the Z-axis mass block through the XY-axis accelerometer spring system, the Z-axis mass block is arranged on the inner side of the silicon substrate and is connected with the silicon substrate through the Z-axis accelerometer spring system, an X-axis movable capacitor plate arranged along the Y-axis direction is arranged on the XY-axis accelerometer mass block, an X-axis fixed capacitor plate corresponding to the X-axis movable capacitor plate is arranged on the Z-axis mass block, a Y-axis movable capacitor plate arranged along the X-axis direction is arranged on the XY-axis accelerometer mass block, a Y-axis fixed capacitor plate corresponding to the Y-axis movable capacitor plate is arranged on the Z-axis mass block, a Z-axis movable capacitor plate is arranged on the bottom of the Z-axis mass block, and a Z-axis fixed capacitor plate corresponding to the Z-axis movable capacitor plate is arranged on the bottom of the silicon substrate.
2. A triaxial capacitive MEMS accelerometer according to claim 1, characterized in that: the mass block of the XY-axis accelerometer is a square mass block, the Z-axis mass block is also a square mass block, a square hole is formed in the center of the Z-axis mass block and is larger than the mass block of the XY-axis accelerometer, and the silicon substrate is a square frame body and is arranged on the outer side of the Z-axis mass block.
3. A triaxial capacitive MEMS accelerometer according to claim 2, characterized in that: the XY-axis accelerometer spring system comprises four groups of plane springs, each group of plane springs is coiled in an S-shaped mode in the XY plane and integrally coiled into an L-shaped mode with two symmetrical sides, one end of each plane spring is connected with one corner outer side of the XY-axis accelerometer mass block, and the other end of each plane spring is connected with one corner inner side of a square hole in the Z-axis mass block.
4. A triaxial capacitive MEMS accelerometer according to claim 2, characterized in that: the Z-axis accelerometer spring system comprises four cantilever beams, and each cantilever beam is perpendicular to one side edge of the silicon substrate and is positioned at the midpoint position of the side edge of the silicon substrate.
5. The triaxial capacitive MEMS accelerometer according to claim 4, wherein: the middle points of the four sides of the Z-axis mass block are provided with a groove which is perpendicular to the side of the Z-axis mass block and is inward, the groove width of the groove is larger than that of the cantilever beam, one end of the cantilever beam is fixed on the inner side of the silicon substrate, and the other end of the cantilever beam is fixed at the bottom of the groove.
6. A triaxial capacitive MEMS accelerometer according to claim 2, characterized in that: at least two groups of X-axis movable capacitance plates and X-axis fixed capacitance plates are arranged in front of the XY-axis accelerometer mass block and the Z-axis mass block, and the two groups of X-axis movable capacitance plates and the X-axis fixed capacitance plates are symmetrically arranged on two sides of the XY-axis accelerometer mass block in the Y-axis direction.
7. A triaxial capacitive MEMS accelerometer according to claim 2, characterized in that: at least two groups of Y-axis movable capacitance plates and Y-axis fixed capacitance plates are arranged in front of the XY-axis accelerometer mass block and the Z-axis mass block, and the two groups of Y-axis movable capacitance plates and the Y-axis fixed capacitance plates are symmetrically arranged on two sides of the XY-axis accelerometer mass block in the X-axis direction.
8. A triaxial capacitive MEMS accelerometer according to claim 1, characterized in that: the XY-axis accelerometer mass block, the XY-axis accelerometer spring system, the Z-axis mass block and the Z-axis accelerometer spring system are processed by adopting an etching process and are suspended on a silicon substrate.
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN221238973U true CN221238973U (en) | 2024-06-28 |
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