CN216900614U

CN216900614U - Three-axis accelerometer

Info

Publication number: CN216900614U
Application number: CN202121928381.1U
Authority: CN
Inventors: 丁希聪; 凌方舟; 蒋乐跃; 苏云鹏
Original assignee: Memsic Semiconductor Wuxi Co Ltd
Current assignee: Memsic Semiconductor Wuxi Co Ltd
Priority date: 2021-08-17
Filing date: 2021-08-17
Publication date: 2022-07-05
Anticipated expiration: 2031-08-17

Abstract

The present invention provides a three-axis accelerometer, comprising: the Z-axis accelerometer comprises a Z mass block, a Z mass block anchor point and a torsion beam, wherein a first space, a second space and a third space are defined in the Z mass block, and the Z mass block anchor point is positioned in the third space; the torsion beam is positioned in the third space and is arranged in parallel to the Y axis, and the torsion beam is connected with the Z mass block anchor point and the Z mass block; the mass of the Z mass block on one side of the torsion beam is different from that of the Z mass block on the other side of the torsion beam, so that the Z mass block generates seesaw-like motion by taking the torsion beam as an axis; an X-axis accelerometer located within the first space; a Y-axis accelerometer located within the second space. Compared with the prior art, the three-axis accelerometer provided by the utility model has the advantages that the whole framework is reasonable and compact, the chip area can be saved, and the cost is reduced. In addition, the sensitivity of the Z-axis accelerometer extended by the frame is high under the same area.

Description

Three-axis accelerometer

[ technical field ] A

The utility model relates to the technical field of micro-mechanical systems, in particular to a three-axis accelerometer.

[ background of the utility model ]

Micro-electromechanical accelerometers are inertial devices based on MEMS technology for measuring linear motion acceleration of object motion. The novel high-voltage switch has the characteristics of small volume, high reliability, low cost, suitability for mass production and the like, so that the novel high-voltage switch has a wide market prospect, and the application fields of the novel high-voltage switch comprise consumer electronics, aerospace, automobiles, medical equipment, weapons and the like.

At present, the triaxial accelerometer generally has two implementation modes, one is a piecing method, and three uniaxial structures or a biaxial structure and a uniaxial structure are combined together to realize the measurement of three axial accelerations. The second is to use a single structure to realize the measurement of the three-axis acceleration. In order to improve market competitiveness, further chip area saving, cost reduction, and sensitivity improvement are required.

Therefore, a new technical solution is needed to solve the above problems.

[ Utility model ] content

One of the objectives of the present invention is to provide a three-axis accelerometer, which has a reasonable and compact structure, and can save chip area and reduce cost. In addition, the sensitivity of the Z-axis accelerometer extended by the frame (mass block) is high under the same area.

According to one aspect of the utility model, there is provided a three-axis accelerometer comprising: the Z-axis accelerometer can sense Z-axis acceleration, and comprises a Z mass block, a Z mass block anchor point and a torsion beam, wherein a first space, a second space and a third space are defined in the Z mass block, and the Z mass block anchor point is positioned in the third space; the torsion beam is positioned in the third space and is placed in parallel to the Y axis, and the torsion beam is connected with the Z mass block anchor point and the Z mass block; the mass of the Z mass block on one side of the torsion beam is different from that of the Z mass block on the other side of the torsion beam, so that the Z mass block generates similar seesaw type motion by taking the torsion beam as an axis; an X-axis accelerometer capable of sensing an X-axis acceleration, the X-axis accelerometer located within the first space; and the Y-axis accelerometer can sense Y-axis acceleration, and is positioned in the second space, wherein the X axis and the Y axis are mutually vertical and define a plane where a base of the three-axis accelerometer is positioned, the Z axis is vertical to the plane defined by the X axis and the Y axis, the X axis is along the left-right direction, and the Y axis is along the up-down direction.

Compared with the prior art, the three-axis accelerometer has the advantages that the X-axis accelerometer and the Y-axis accelerometer are arranged in the mass block of the Z-axis accelerometer, the whole structure is reasonable and compact, the area of a chip can be saved, and the cost is reduced. In addition, the sensitivity of the Z-axis accelerometer extended by the frame (mass block) is high under the same area.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

FIG. 1 is a schematic diagram of the overall structure of a three-axis accelerometer according to one embodiment of the utility model;

FIG. 2 is a schematic diagram of the structure of the X-axis accelerometer of the three-axis accelerometer shown in FIG. 1 according to the present invention;

FIG. 3 is a schematic diagram of the structure of the Y-axis accelerometer of FIG. 1 according to the present invention;

FIG. 4 is a schematic diagram of the structure of the Z-axis accelerometer of the three-axis accelerometer shown in FIG. 1 according to the present invention;

FIG. 5 is a schematic structural diagram of a torsion beam protection mechanism of the tri-axial accelerometer shown in FIG. 1 according to the present invention;

FIG. 6 is a schematic diagram of the three-axis accelerometer of FIG. 1 sensing acceleration in the X-axis according to the present invention;

FIG. 7 is a schematic diagram of the three-axis accelerometer of FIG. 1 sensing acceleration in the Y-axis according to the present invention;

FIG. 8 is a schematic diagram of the tri-axial accelerometer of FIG. 1 sensing Z-axis acceleration in accordance with the present invention;

figure 9 is a schematic diagram of the overall structure of a triaxial accelerometer according to another embodiment of the present invention.

Wherein, 1a-X mass block; 1b-Y mass block; 1c-Z mass block;

2 a-a first transverse resilient beam; 2 b-a second transverse resilient beam; 2 c-a first longitudinal spring beam; 2 d-a second longitudinal elastic beam; 2 e-a first twist beam; 2 f-a second torsion beam; 2 g-torsion beam protection mechanism;

3 a-a first X-axis detection electrode; 3 b-a second X-axis detection electrode; 3 c-a third X-axis detection electrode; 3 d-a fourth X-axis detection electrode; 3 e-first Y-axis detection electrode; 3 f-a second Y-axis detection electrode; 3 g-a third Y-axis detection electrode; 3 h-a fourth Y-axis detection electrode; 3 i-a first Z-axis detection electrode; 3 j-a second Z-axis detection electrode;

4a-X mass block anchor points; 4b-Y mass block anchor points; 4c-Z mass anchor points.

5 a-a first transverse beam connecting arm; 5 b-a second transverse beam connecting arm; 5 c-a first longitudinal beam connecting arm; 5 d-a second longitudinal beam connecting arm;

6 a-transversely movable thinning teeth; 6 b-transversely fixing thinning teeth; 6 c-longitudinally movable thinning teeth; 6 d-longitudinally fixing the sparse teeth.

7 a-a first space; 7 b-a second space; 7 c-third space.

[ detailed description ] embodiments

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the utility model. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Unless otherwise specified, the terms connected, and connected as used herein mean electrically connected, directly or indirectly.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," "coupled," and the like are to be construed broadly; for example, the connection can be fixed, detachable or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other suitable relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Aiming at the problems in the prior art, the utility model provides a triaxial accelerometer. Fig. 1 is a schematic diagram of an overall structure of a triaxial accelerometer according to an embodiment of the present invention.

The three-axis accelerometers shown in FIG. 1 include an X-axis accelerometer (not identified), a Y-axis accelerometer (not identified), and a Z-axis accelerometer (not identified). The Z-axis accelerometer can sense Z-axis acceleration, the Z-axis accelerometer comprises a Z mass block 1c, and a first space 7a and a second space 7b are defined in the Z mass block 1 c; an X-axis accelerometer capable of sensing an X-axis acceleration, the X-axis accelerometer being located within the first space 7 a; a Y-axis accelerometer can sense Y-axis acceleration, the Y-axis accelerometer being located within the second space 7 b.

To better illustrate the structure of the tri-axial accelerometer of the present invention, a three-dimensional rectangular coordinate system can be established, in the embodiment shown in fig. 1, the X-axis and the Y-axis are perpendicular to each other and define the plane of the base of the tri-axial accelerometer, the Z-axis is perpendicular to the plane defined by the X-axis and the Y-axis, and the three-dimensional rectangular coordinate system established by the X-axis, the Y-axis and the Z-axis is shown in fig. 1, wherein the X-axis is along the left-right direction, the Y-axis is along the up-down direction, and the Z-axis is along the direction perpendicular to the paper.

As shown in fig. 1, 4 and 5, the Z-axis accelerometer of the tri-axial accelerometer further includes a Z mass anchor point 4c,

torsion beams

2e and 2f, a first Z-axis detection electrode 3i and a second Z-axis detection electrode 3j, and a third space 7c spaced apart from the first space 7a and the second space 7b is defined in the Z mass 1 c; the Z mass anchor point 4c is located within the third space 7 c; the

torsion beams

2e and 2f are positioned in the third space 7c, and the

torsion beams

2e and 2f are connected with the Z mass block anchor point 4c and the Z mass block 1 c; the mass of the Z mass block 1c on one side (or left side) of the

torsion beams

2e and 2f is different from the mass of the Z mass block 1c on the other side (or right side) of the

torsion beams

2e and 2f, so that the Z mass block 1c generates similar seesaw type motion by taking the

torsion beams

2e and 2f as axes. The first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j are located below the Z mass block 1c and symmetrically arranged on the left side and the right side of the

torsion beams

2e and 2 f. When the Z-axis acceleration is input in a sensitive (or induction) mode, the Z mass block 1c can be twisted or pivoted (or similar seesaw type movement) by taking the

torsion beams

2e and 2f as axes, the first Z-axis detection electrode 3i detects the distance change between the Z mass block 1c, the second Z-axis detection electrode 3j detects the distance change between the Z mass block 1c, specifically, the capacitance of the first Z-axis detection electrode 3i and the capacitance of the second Z-axis detection electrode 3j after the Z-axis acceleration rate is sensed are increased and decreased, the difference between the two capacitances is obtained to obtain the capacitance change caused by the Z-axis acceleration, and then the input Z-axis acceleration rate is obtained.

As shown in fig. 1, 4 and 5, the Z-axis accelerometer of the triaxial accelerometer further includes a torsion beam protection mechanism 2g located in the third space 7c, the torsion beam protection mechanism 2g is connected to the Z mass anchor point 4c and the Z mass 1c, and the torsion beam protection mechanism 2g is symmetrically distributed on the left and right sides of the

torsion beams

2e and 2f to protect the

torsion beams

2e and 2 f.

In the particular embodiment shown in fig. 1, 4 and 5, the

twist beams

2e, 2f are positioned parallel to the Y-axis (or the extension direction of the

twist beams

2e, 2f is parallel to the Y-axis); the number of the

torsion beams

2e and 2f is two, and the torsion beams are respectively a first torsion beam 2e and a second torsion beam 2f, wherein the first torsion beam 2e is positioned above the Z mass block anchor point 4c, and the first torsion beam 2e is connected with the Z mass block anchor point 4c and the Z mass block 1 c; the second torsion beam 2f is positioned below the Z mass anchor point 4c, and the second torsion beam 2f connects the Z mass anchor point 4c and the Z mass 1 c. Torsion beam protection mechanism 2g includes four pairs of torsion beam protection comb tooth structures, and every torsion beam protection comb tooth structure all includes many broach parallel with the Y axle. The two pairs of torsion beam protection comb tooth structures are positioned above the Z mass block anchor point 4c and are respectively positioned at the left side and the right side of the first torsion beam 2 e; in addition, two pairs of torsion beam protection comb tooth structures are arranged below the Z mass block anchor point 4c and are respectively arranged at the left side and the right side of the second torsion beam 2f, one torsion beam protection comb tooth structure in each pair of torsion beam protection comb tooth structures is connected with the Z mass block anchor point 4c, the other torsion beam protection comb tooth structure is connected with the Z mass block 1c, and each pair of torsion beam protection comb tooth structures are arranged in an interdigital mode. The torsion beam protection mechanism 2g is provided to prevent the

torsion beams

2e and 2f from being broken due to an excessive impact on the Z mass 1c, and is not necessarily added.

In the embodiment shown in fig. 1, 4 and 5, the Z mass anchor point 4c is fixedly disposed on the substrate (not shown); the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j are fixedly disposed on a substrate (not shown); the Z mass block 1c is connected with a Z mass block anchor point 4c through

torsion beams

2e and 2f, and the Z mass block 1c and the

torsion beams

2e and 2f are suspended above the substrate; a torsion beam protection mechanism 2g is suspended above the base.

In the particular embodiment shown in fig. 1, 4 and 5, the first torsion beam 2e and the second torsion beam 2f are symmetrically distributed about the X axis; the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j are symmetrically distributed about the Y-axis; the four torsion beam protection comb tooth structures are symmetrically distributed on the whole body about an X axis and a Y axis.

As shown in fig. 1 and fig. 2, the X-axis accelerometer of the three-axis accelerometer includes an X mass block 1a and

X-axis detection electrodes

3a, 3b, 3c, and 3d located in the X mass block 1a, wherein a plurality of transverse fixed comb teeth 6b parallel to the Y axis are provided in the

X-axis detection electrodes

3a, 3b, 3c, and 3d, and a plurality of transverse movable comb teeth 6a parallel to the Y axis are provided in the X mass block 1a, wherein a plurality of transverse fixed comb teeth 6b in the

X-axis detection electrodes

3a, 3b, 3c, and 3d and a plurality of transverse movable comb teeth 6a in the X mass block 1a are arranged in an interdigital manner to form an interdigital capacitor. When the acceleration of the X axis is input in a sensitive (or induction) mode, the X mass block 1a can move along the X axis, the X

axis detection electrodes

3a, 3b, 3c and 3d detect the distance change with the X mass block 1a, specifically, compared with the capacitance of the X

axis detection electrodes

3a, 3b, 3c and 3d before the acceleration of the X axis, the capacitance of the X

axis detection electrodes

3a, 3b, 3c and 3d after the acceleration of the X axis is sensed is increased or decreased, the difference between the two capacitances is obtained to obtain the capacitance change caused by the acceleration of the X axis, and then the input acceleration rate of the X axis is obtained.

In the embodiment shown in fig. 1 and 2, four X-axis detection electrodes are located in the X mass block 1a, which are respectively a first X-axis detection electrode 3a, a second X-axis detection electrode 3b, a third X-axis detection electrode 3c, and a fourth X-axis detection electrode 3d, wherein the first X-axis detection electrode 3a and the second X-axis detection electrode 3b are respectively located on the left and right sides of the upper portion in the X mass block 1a, and the third X-axis detection electrode 3c and the fourth X-axis detection electrode 3d are respectively located on the left and right sides of the lower portion in the X mass block 1 a.

As shown in fig. 1 and 2, the X-axis accelerometer further includes an X mass anchor point 4a disposed in the X mass 1a, a transverse elastic

beam connecting arm

5a, 5b and a transverse

elastic beam

2a, 2b, wherein the X mass anchor point 4a is connected to the X mass 1a sequentially through the transverse elastic

beam connecting arm

5a, 5b and the transverse

elastic beam

2a, 2 b.

In the particular embodiment shown in fig. 1 and 2, there are two transverse resilient

beam connecting arms

5a, 5b, respectively a first transverse resilient beam connecting arm 5a and a second transverse resilient beam connecting arm 5 b; the number of the transverse

elastic beams

2a and 2b is two, and the transverse elastic beams are respectively a first transverse elastic beam 2a and a second transverse elastic beam 2b, wherein the first transverse elastic beam 2a and the second transverse elastic beam 2b are respectively positioned at the left side and the right side of the X mass block anchor point 4 a; the first transverse elastic beam connecting arm 5a is positioned between the X mass block anchor point 4a and the first transverse elastic beam 2a, and the second transverse elastic beam connecting arm 5b is positioned between the X mass block anchor point 4a and the second transverse elastic beam 2 b; one end of an X mass block anchor point 4a is connected with the X mass block 1a sequentially through a first transverse elastic beam connecting arm 5a and a first transverse elastic beam 2a, and the other end of the X mass block anchor point 4a is connected with the X mass block 1a sequentially through a second transverse elastic beam connecting arm 5b and a second transverse elastic beam 2 b.

In the particular embodiment shown in fig. 1 and 2, the first 5a and second 5b transverse resilient beam connecting arms are placed parallel to the X-axis; the first and second lateral

elastic beams

2a and 2b are disposed parallel to the Y-axis (or the extending direction of the first and second lateral

elastic beams

2a and 2b is parallel to the Y-axis); the first X-axis detection electrode 3a and the second X-axis detection electrode 3b are positioned above the X mass block anchor point 4a and between the first transverse elastic beam 2a and the second transverse elastic beam 2 b; the third X-axis detection electrode 3c and the fourth X-axis detection electrode 3d are located below the X mass anchor point 4a and between the first transverse elastic beam 2a and the second transverse elastic beam 2 b.

In the embodiment shown in fig. 1 and 2, the X-mass anchor points 4a are fixed to the substrate;

x-axis detection electrodes

3a, 3b, 3c and 3d are fixed on the substrate; the X mass 1a, the transverse spring

beam connecting arms

5a, 5b and the

transverse spring beams

2a, 2b are suspended above the substrate. Wherein the first and second transverse resilient

beam connecting arms

5a, 5b are symmetrical about the Y axis; the first transverse resilient beam 2a and the second transverse resilient beam 2b are symmetrical about the Y-axis; the first X-axis detection electrode 3a, the second X-axis detection electrode 3b, the third X-axis detection electrode 3c, and the fourth X-axis detection electrode 3d are symmetrical with respect to the X-axis and the Y-axis as a whole.

As shown in fig. 1 and fig. 3, the Y-axis accelerometer of the three-axis accelerometer includes a Y mass block 1b and Y-

axis detection electrodes

3e, 3f, 3g, and 3h located in the Y mass block 1b, a plurality of longitudinal fixed comb teeth 6d parallel to the X axis are provided in the Y-

axis detection electrodes

3e, 3f, 3g, and 3h, a plurality of longitudinal movable comb teeth 6c parallel to the X axis are provided in the Y mass block 1b, wherein the plurality of longitudinal fixed comb teeth 6d in the Y-

axis detection electrodes

3e, 3f, 3g, and 3h and the plurality of longitudinal movable comb teeth 6c in the Y mass block 1b are arranged in an interdigital manner to form an interdigital capacitor. When the acceleration of the Y axis is input in a sensitive (or induction) mode, the Y mass block 1b can move along the Y axis, the Y

axis detection electrodes

3e, 3f, 3g and 3h detect the distance change with the Y mass block 1b, specifically, compared with the capacitance of the Y

axis detection electrodes

3e, 3f, 3g and 3h before the acceleration of the Y axis, the capacitance of the Y

axis detection electrodes

3e, 3f, 3g and 3h after the acceleration of the Y axis is sensed is increased or decreased, the difference between the capacitance and the capacitance is obtained to obtain the capacitance change caused by the acceleration of the Y axis, and then the input acceleration rate of the Y axis is obtained.

In the specific embodiment shown in fig. 1 and 3, the number of the Y-axis detection electrodes located in the Y mass block 1b is four, and the number of the Y-axis detection electrodes is respectively a first Y-axis detection electrode 3e, a second Y-axis detection electrode 3f, a third Y-axis detection electrode 3g, and a fourth Y-axis detection electrode 3h, wherein the first Y-axis detection electrode 3e and the second Y-axis detection electrode 3f are respectively located at the upper and lower ends of the left side in the Y mass block 1b, and the third Y-axis detection electrode 3g and the fourth Y-axis detection electrode 3h are respectively located at the upper and lower ends of the right side in the Y mass block 1 b.

As shown in fig. 1 and 3, the Y-axis accelerometer further includes a Y mass anchor point 4b disposed in the Y mass 1b, longitudinal elastic

beam connecting arms

5c and 5d, and longitudinal

elastic beams

2c and 2d, wherein the Y mass anchor point 4b is connected to the Y mass 1b sequentially through the longitudinal elastic

beam connecting arms

5c and 5d and the longitudinal

elastic beams

2c and 2 d.

In the particular embodiment shown in fig. 1 and 3, there are two longitudinal resilient

beam connecting arms

5c, 5d, a first longitudinal resilient beam connecting arm 5c and a second longitudinal resilient beam connecting arm 5d, respectively; the number of the longitudinal

elastic beams

2c and 2d is two, and the longitudinal elastic beams are respectively a first longitudinal elastic beam 2c and a second longitudinal elastic beam 2d, wherein the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are respectively positioned at the upper end and the lower end of the Y mass block anchor point 4 b; the first longitudinal elastic beam connecting arm 5c is positioned between the Y mass block anchor point 4b and the first longitudinal elastic beam 2c, and the second longitudinal elastic beam connecting arm 5d is positioned between the Y mass block anchor point 4b and the second longitudinal elastic beam 2 d; one end of a Y mass block anchor point 4b is connected with the Y mass block 1b through a first longitudinal elastic beam connecting arm 5c and a first longitudinal elastic beam 2c in sequence, and the other end of the Y mass block anchor point 4b is connected with the Y mass block 1b through a second longitudinal elastic beam connecting arm 5d and a second longitudinal elastic beam 2d in sequence.

In the particular embodiment shown in fig. 1 and 3, the first and second longitudinal resilient

beam connecting arms

5c, 5d are positioned parallel to the Y-axis; the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are disposed parallel to the X axis (or the extending direction of the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d is parallel to the X axis); the first Y-axis detection electrode 3e and the second Y-axis detection electrode 3f are positioned on the left side of the Y mass block anchor point 4b and between the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2 d; the third Y-axis detection electrode 3g and the fourth Y-axis detection electrode 3h are located on the right side of the Y mass anchor point 4b and between the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2 d.

In the embodiment shown in fig. 1 and 3, the Y-mass anchor 4b is fixed to the substrate; the Y-

axis detection electrodes

3e, 3f, 3g, 3h are fixed on the substrate; the Y mass block 1b, the longitudinal elastic

beam connecting arms

5c and 5d and the longitudinal

elastic beams

2c and 2d are suspended above the substrate. Wherein the first longitudinal resilient beam connecting arm 5c and the second longitudinal resilient beam connecting arm 5d are symmetrical about the X-axis; the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are symmetrical about the X axis; the first Y-axis detection electrode 3e, the second Y-axis detection electrode 3f, the third Y-axis detection electrode 3g, and the fourth Y-axis detection electrode 3h are entirely symmetrical about the X-axis and the Y-axis.

In the embodiment shown in fig. 1, the X-axis accelerometer and the Y-axis accelerometer, which may be arranged along the X-axis or the Y-axis, are located in the Z mass 1c at the same lateral position of the

torsion beams

2e, 2 f. In the embodiment shown in FIG. 1, the isolation between the X-axis accelerometer and the Y-axis accelerometer is complete, and in another embodiment, the mass may be shared by the X-axis accelerometer and the Y-axis accelerometer shown in FIG. 1.

Please refer to fig. 9, which is a schematic diagram illustrating an overall structure of a three-axis accelerometer according to another embodiment of the present invention, which is different from the three-axis accelerometer shown in fig. 1 only in that: the X-axis accelerometer shown in fig. 9 is not provided with the X mass anchor point 4a and the transverse elastic

beam connecting arms

5a and 5b, and the X mass 1a is connected with the Z mass 1c through the transverse

elastic beams

2a and 2 b; the Y-axis accelerometer shown in fig. 9 is not provided with the Y mass anchor point 4b and the longitudinal elastic

beam connecting arms

5c and 5d, and the Y mass 1b is connected with the Z mass 1c through the longitudinal

elastic beams

2c and 2 d.

In the embodiment shown in fig. 9, the lateral

elastic beams

2a and 2b are disposed in the first space 7a and outside the X mass 1a, and the X mass 1a is connected to the Z mass 1c through the lateral

elastic beams

2a and 2 b.

In the specific embodiment shown in fig. 9, there are two transverse

elastic beams

2a, 2b, namely a first transverse elastic beam 2a and a second transverse elastic beam 2b, wherein the first transverse elastic beam 2a and the second transverse elastic beam 2b are respectively located at the left and right sides of the X mass 1 a; the X mass block 1a is connected with the Z mass block 1c through the first transverse elastic beam 2 a; the X mass 1a is connected to the Z mass 1c via the second transverse spring beam 2 b. The first and second lateral

elastic beams

2a and 2b are placed parallel to the Y-axis (or the extending direction of the first and second lateral

elastic beams

2a and 2b is parallel to the Y-axis), and the first and second lateral

elastic beams

2a and 2b are symmetrical with respect to the Y-axis.

In the embodiment shown in fig. 9, longitudinal

elastic beams

2c and 2d are disposed in the second space 7b and outside the Y mass 1b, and the Y mass 1b is connected to the Z mass 1c through the longitudinal

elastic beams

2c and 2 d.

In the specific embodiment shown in fig. 9, there are two longitudinal

elastic beams

2c and 2d, namely, a first longitudinal elastic beam 2c and a second longitudinal elastic beam 2d, wherein the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are respectively located at the left and right sides of the Y mass 1 b; the Y mass block 1b is connected with the Z mass block 1c through the first longitudinal elastic beam 2 c; the Y mass 1b is connected to the Z mass 1c via the second longitudinal spring beam 2 d. The first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are placed parallel to the X axis (or the extending direction of the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d is parallel to the X axis), and the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are symmetrical with respect to the Y axis.

As can be seen from the above, in the embodiment shown in fig. 1, 2 and 3, the X-axis accelerometer is independently disposed in the first space 7a inside the Z mass 1c, i.e. the X-axis accelerometer and the Z mass 1c are independent from each other and are not connected; the Y-axis accelerometer is independently disposed in the second space 7b inside the Z mass 1c, i.e. the Y-axis accelerometer and the Z mass 1c are independent of each other and not connected. In the embodiment shown in fig. 9, the X-axis accelerometer and the Y-axis accelerometer are each connected to the Z mass 1c by elastic beams 2 a-2 d.

The detection principle of the tri-axial accelerometer shown in fig. 1 of the present invention is described below.

Detection principle of first-axis accelerometer and X-axis accelerometer

Please refer to fig. 6, which is a schematic diagram illustrating the three-axis accelerometer shown in fig. 1 sensing the acceleration of the X-axis according to the present invention.

The

X-axis detection electrodes

3a, 3b, 3c and 3d are internally provided with a plurality of transverse fixed comb teeth 6b parallel to the Y axis, the X-axis mass block 1a is internally provided with a plurality of transverse movable comb teeth 6a parallel to the Y axis, when the acceleration of the X axis is input in a sensitive (or induction) mode, the X-axis mass block 1a drives the plurality of transverse movable comb teeth 6a to move along the X axis, the transverse fixed comb teeth 6b in the

X-axis detection electrodes

3a, 3b, 3c and 3d sense that the distance between the transverse movable comb teeth 6a in the X-axis mass block 1a changes, the capacitance of the transverse fixed comb teeth and the capacitance of the transverse movable comb teeth change, and the measurement of the acceleration of the X axis is realized by detecting the capacitance change of the transverse fixed comb teeth 6b in the

X-axis detection electrodes

3a, 3b, 3c and 3 d. Specifically, compared with the capacitance of the

X-axis detection electrodes

3a, 3b, 3c, and 3d sensitive to the X-axis acceleration, the capacitance of the

X-axis detection electrodes

3a, 3b, 3c, and 3d sensitive to the X-axis acceleration is increased or decreased, and the difference between the two capacitances is obtained to obtain the capacitance change caused by the X-axis acceleration, thereby obtaining the input X-axis acceleration rate.

It should be noted that fig. 6 is only an example showing a moving direction of the X mass 1a along the X axis when the acceleration input of the X axis is sensed.

Two-axis and Y-axis accelerometer detection principle

Please refer to fig. 7, which is a schematic diagram illustrating the three-axis accelerometer shown in fig. 1 sensing the acceleration of the Y-axis.

The Y-

axis detection electrodes

3e, 3f, 3g and 3h are internally provided with a plurality of longitudinal fixed comb teeth 6d parallel to the X axis, the Y mass block 1b is internally provided with a plurality of longitudinal movable comb teeth 6c parallel to the X axis, when the Y-axis acceleration is input in a sensitive (or induction) mode, the Y mass block 1b drives the longitudinal movable comb teeth 6c to move along the Y axis, the longitudinal fixed comb teeth 6d in the Y-

axis detection electrodes

3e, 3f, 3g and 3h sense that the distance between the longitudinal movable comb teeth 6c in the Y mass block 1c changes, the capacitance of the two changes, and the measurement of the Y-axis acceleration is realized by detecting the capacitance change of the longitudinal movable comb teeth 6c in the Y-

axis detection electrodes

3e, 3f, 3g and 3 h. Specifically, compared with the capacitance of the Y-

axis detection electrodes

3e, 3f, 3g, and 3h before the Y-axis acceleration is sensed, the capacitance of the Y-

axis detection electrodes

3e, 3f, 3g, and 3h after the Y-axis acceleration is sensed is increased or decreased, and the difference between the capacitance of the Y-

axis detection electrodes

3e, 3f, 3g, and 3h and the capacitance change caused by the Y-axis acceleration is obtained, so as to obtain the magnitude of the input Y-axis acceleration rate.

It should be noted that fig. 7 is only an example showing a moving direction of the Y mass 1b along the Y axis when the Y-axis acceleration input is sensed.

Three-axis and Z-axis accelerometer detection principle

Please refer to fig. 8, which is a schematic diagram illustrating the three-axis accelerometer shown in fig. 1 sensing Z-axis acceleration according to the present invention.

The first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j are located below the Z mass block 1c and symmetrically arranged on the left side and the right side of the

torsion beams

2e and 2 f. When the Z-axis acceleration is input in a sensitive (or induction) mode, the Z mass block 1c is enabled to be twisted (or move like a seesaw) by taking the

torsion beams

2e and 2f as axes, the distances between the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j on the two sides and the Z mass block 1c are changed, the capacitance of the first Z-axis detection electrode 3i and the capacitance of the second Z-axis detection electrode 3j are changed, and the measurement of the Z-axis acceleration is achieved by detecting the capacitance change of the first Z-axis detection electrode 3i and the capacitance change of the second Z-axis detection electrode 3 j. It can also be said that the first Z-axis detection electrode 3i detects a change in distance from the Z mass block 1c, the second Z-axis detection electrode 3j detects a change in distance from the Z mass block 1c, specifically, the capacitance of the first Z-axis detection electrode 3i and the capacitance of the second Z-axis detection electrode 3j, which are sensitive to the Z-axis acceleration rate, are increased and decreased, and the difference between the first Z-axis detection electrode 3i and the second Z-axis detection electrode is used to obtain a change in capacitance caused by the Z-axis acceleration, thereby obtaining the magnitude of the input Z-axis acceleration rate.

It should be noted that fig. 8 shows only one movement direction of the Z mass 1c about the

torsion beams

2e and 2f when the Z-axis acceleration input is sensed.

In the embodiment shown in fig. 1 and 9, a certain number of through holes, blind holes, hollow parts or semi-hollow parts may be disposed on the X mass block 1a, the Y mass block 1b and the Z mass block 1c to improve the sensitivity of the triaxial accelerometer.

In summary, the three-axis accelerometer provided by the present invention includes an X-axis accelerometer (not shown), a Y-axis accelerometer (not shown) and a Z-axis accelerometer (not shown). The Z-axis accelerometer can sense Z-axis acceleration, the Z-axis accelerometer comprises a Z mass block 1c, and a first space 7a and a second space 7b are defined in the Z mass block 1 c; an X-axis accelerometer capable of sensing an X-axis acceleration, the X-axis accelerometer being located within the first space 7 a; a Y-axis accelerometer can sense Y-axis acceleration, the Y-axis accelerometer being located within the second space 7 b. Therefore, the triaxial accelerometer provided by the utility model has a reasonable and compact overall structure, can save the chip area and reduce the cost. In addition, the sensitivity of the Z-axis accelerometer extended by the frame (mass block) is high under the same area.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

While embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications and variations may be made therein by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A triaxial accelerometer, comprising:

the Z-axis accelerometer can sense Z-axis acceleration, and comprises a Z mass block, a Z mass block anchor point and a torsion beam, wherein a first space, a second space and a third space are defined in the Z mass block, and the Z mass block anchor point is positioned in the third space; the torsion beam is positioned in the third space and is placed in parallel to the Y axis, and the torsion beam is connected with the Z mass block anchor point and the Z mass block; the mass of the Z mass block on one side of the torsion beam is different from that of the Z mass block on the other side of the torsion beam, so that the Z mass block generates seesaw-like motion by taking the torsion beam as an axis;

an X-axis accelerometer capable of sensing X-axis acceleration, the X-axis accelerometer located within the first space;

a Y-axis accelerometer capable of sensing a Y-axis acceleration, the Y-axis accelerometer located within the second space,

the X axis and the Y axis are mutually vertical and define a plane where a base of the three-axis accelerometer is located, the Z axis is perpendicular to the plane defined by the X axis and the Y axis, the X axis is along the left-right direction, and the Y axis is along the up-down direction.

2. The tri-axial accelerometer of claim 1,

the Z-axis accelerometer further comprises a first Z-axis sense electrode and a second Z-axis sense electrode,

the first Z-axis detection electrode and the second Z-axis detection electrode are positioned below the Z mass block and symmetrically arranged at two sides of the torsion beam;

the X-axis accelerometer and the Y-axis accelerometer are positioned on the same side of the torsion beam;

the X-axis accelerometer is independently arranged in the first space inside the Z mass block, the Y-axis accelerometer is independently arranged in the second space inside the Z mass block, or the X-axis accelerometer and the Y-axis accelerometer are respectively connected with the Z mass block through elastic beams.

3. The tri-axial accelerometer of claim 2,

the Z-axis accelerometer of the triaxial accelerometer further comprises torsion beam protection mechanisms positioned in the third space, the torsion beam protection mechanisms are connected with the Z mass block anchor points and the Z mass block, and the torsion beam protection mechanisms are symmetrically distributed on the left side and the right side of the torsion beam;

the Z mass block anchor point is fixedly arranged on the substrate; the first Z-axis detection electrode and the second Z-axis detection electrode are fixedly arranged on the substrate; the Z mass and the torsion beam are suspended above the base; the twist beam protection mechanism is suspended above the base.

4. The tri-axial accelerometer of claim 3,

the number of the torsion beams is two, namely a first torsion beam and a second torsion beam, wherein the first torsion beam is positioned above the Z mass block anchor point, and the first torsion beam is connected with the Z mass block anchor point and the Z mass block; the second torsion beam is positioned below the Z mass block anchor point and is connected with the Z mass block anchor point and the Z mass block;

the torsion beam protection mechanism comprises four pairs of torsion beam protection comb tooth structures, each torsion beam protection comb tooth structure comprises a plurality of comb teeth parallel to the Y axis, and the two pairs of torsion beam protection comb tooth structures are located above the Z mass block anchor points and are respectively located on the left side and the right side of the first torsion beam; the other two pairs of torsion beam protection comb tooth structures are positioned below the Z mass block anchor point and are respectively positioned at the left side and the right side of the second torsion beam, one torsion beam protection comb tooth structure in each pair of torsion beam protection comb tooth structures is connected with the Z mass block anchor point, the other torsion beam protection comb tooth structure is connected with the Z mass block, and each pair of torsion beam protection comb tooth structures are distributed in an interdigital manner;

the first torsion beam and the second torsion beam are symmetrically distributed about an X axis; the first Z-axis detection electrode and the second Z-axis detection electrode are symmetrically distributed about a Y axis; the four pairs of torsion beam protection comb tooth structures are symmetrically distributed on the whole body about an X axis and a Y axis.

5. The tri-axial accelerometer of claim 2,

an X-axis accelerometer of the tri-axial accelerometer includes an X mass and an X-axis detection electrode located within the X mass.

6. The tri-axial accelerometer of claim 5,

the X-axis accelerometer also comprises an X mass block anchor point, a transverse elastic beam connecting arm and a transverse elastic beam which are arranged in the X mass block,

the X mass block anchor point is connected with the X mass block through the transverse elastic beam connecting arm and the transverse elastic beam in sequence.

7. The tri-axial accelerometer of claim 6,

the X-axis detection electrodes positioned in the X mass block are four and are respectively a first X-axis detection electrode, a second X-axis detection electrode, a third X-axis detection electrode and a fourth X-axis detection electrode, wherein the first X-axis detection electrode and the second X-axis detection electrode are respectively positioned on the left side and the right side of the upper part in the X mass block, and the third X-axis detection electrode and the fourth X-axis detection electrode are respectively positioned on the left side and the right side of the lower part in the X mass block;

the two transverse elastic beam connecting arms are respectively a first transverse elastic beam connecting arm and a second transverse elastic beam connecting arm; the number of the transverse elastic beams is two, namely a first transverse elastic beam and a second transverse elastic beam, wherein the first transverse elastic beam and the second transverse elastic beam are respectively positioned on the left side and the right side of the anchor point of the X mass block; the first transverse elastic beam connecting arm is positioned between the X mass block anchor point and the first transverse elastic beam, and the second transverse elastic beam connecting arm is positioned between the X mass block anchor point and the second transverse elastic beam; one end of the X mass block anchor point is connected with the X mass block sequentially through the first transverse elastic beam connecting arm and the first transverse elastic beam, and the other end of the X mass block anchor point is connected with the X mass block sequentially through the second transverse elastic beam connecting arm and the second transverse elastic beam.

8. The tri-axial accelerometer of claim 7,

the first transverse elastic beam connecting arm and the second transverse elastic beam connecting arm are arranged in parallel to the X axis; the first transverse elastic beam and the second transverse elastic beam are arranged in parallel to the Y axis; the first X-axis detection electrode and the second X-axis detection electrode are positioned above the X mass block anchor point and between the first transverse elastic beam and the second transverse elastic beam; the third X-axis detection electrode and the fourth X-axis detection electrode are positioned below the X mass block anchor point and between the first transverse elastic beam and the second transverse elastic beam;

the X mass block anchor point is fixed on the substrate; the X-axis detection electrode is fixed on the substrate; the X mass block, the transverse elastic beam connecting arm and the transverse elastic beam are suspended above the substrate;

the first transverse elastic beam connecting arm and the second transverse elastic beam connecting arm are symmetrical around the Y axis; the first and second transverse elastic beams are symmetrical about a Y axis; the first X-axis detection electrode, the second X-axis detection electrode, the third X-axis detection electrode and the fourth X-axis detection electrode are integrally symmetrical about the X axis and the Y axis.

9. The tri-axial accelerometer of claim 2,

the Y-axis accelerometer of the tri-axis accelerometer comprises a Y mass block and a Y-axis detection electrode positioned in the Y mass block.

10. The tri-axial accelerometer of claim 9,

the Y-axis accelerometer also comprises a Y mass block anchor point, a longitudinal elastic beam connecting arm and a longitudinal elastic beam which are arranged in the Y mass block,

and the Y mass block anchor point is connected with the Y mass block sequentially through the longitudinal elastic beam connecting arm and the longitudinal elastic beam.

11. The tri-axial accelerometer of claim 10,

the Y-axis detection electrodes positioned in the Y mass block are four and are respectively a first Y-axis detection electrode, a second Y-axis detection electrode, a third Y-axis detection electrode and a fourth Y-axis detection electrode, wherein the first Y-axis detection electrode and the second Y-axis detection electrode are respectively positioned at the upper end and the lower end of the left side in the Y mass block, and the third Y-axis detection electrode and the fourth Y-axis detection electrode are respectively positioned at the upper end and the lower end of the right side in the Y mass block;

the two longitudinal elastic beam connecting arms are respectively a first longitudinal elastic beam connecting arm and a second longitudinal elastic beam connecting arm; the two longitudinal elastic beams are respectively a first longitudinal elastic beam and a second longitudinal elastic beam, and the first longitudinal elastic beam and the second longitudinal elastic beam are respectively positioned at the upper end and the lower end of the Y mass block anchor point; the first longitudinal elastic beam connecting arm is positioned between the Y mass block anchor point and the first longitudinal elastic beam, and the second longitudinal elastic beam connecting arm is positioned between the Y mass block anchor point and the second longitudinal elastic beam; one end of the Y mass block anchor point is connected with the Y mass block through the first longitudinal elastic beam connecting arm and the first longitudinal elastic beam in sequence, and the other end of the Y mass block anchor point is connected with the Y mass block through the second longitudinal elastic beam connecting arm and the second longitudinal elastic beam in sequence.

12. The tri-axial accelerometer of claim 11,

the first longitudinal elastic beam connecting arm and the second longitudinal elastic beam connecting arm are arranged in parallel to the Y axis; the first longitudinal elastic beam and the second longitudinal elastic beam are arranged in parallel to the X axis; the first Y-axis detection electrode and the second Y-axis detection electrode are positioned on the left side of the Y mass block anchor point and positioned between the first longitudinal elastic beam and the second longitudinal elastic beam; the third Y-axis detection electrode and the fourth Y-axis detection electrode are positioned on the right side of the Y mass block anchor point and are positioned between the first longitudinal elastic beam and the second longitudinal elastic beam;

the Y mass block anchor point is fixed on the substrate; the Y-axis detection electrode is fixed on the substrate; the Y mass, the longitudinal elastic beam connecting arm and the longitudinal elastic beam are suspended above the substrate;

the first longitudinal elastic beam connecting arm and the second longitudinal elastic beam connecting arm are symmetrical about an X axis; the first longitudinal elastic beam and the second longitudinal elastic beam are symmetrical about an X axis; the first Y-axis detection electrode, the second Y-axis detection electrode, the third Y-axis detection electrode and the fourth Y-axis detection electrode are integrally symmetrical about the X axis and the Y axis.

13. The tri-axial accelerometer of claim 5,

the X-axis accelerometer further comprises a transverse elastic beam arranged in the first space and positioned outside the X mass,

the X mass block is connected with the Z mass block through the transverse elastic beam.

14. The tri-axial accelerometer of claim 13,

the number of the transverse elastic beams is two, namely a first transverse elastic beam and a second transverse elastic beam, wherein the first transverse elastic beam and the second transverse elastic beam are respectively positioned on the left side and the right side of the X mass block; the X mass block is connected with the Z mass block through the first transverse elastic beam; the X mass block is connected with the Z mass block through the second transverse elastic beam;

the first transverse elastic beam and the second transverse elastic beam are arranged in parallel to the Y axis; the X-axis detection electrode is fixed on the substrate; the X mass block and the transverse elastic beam are suspended above the substrate;

the first and second transverse elastic beams are symmetrical about a Y axis; the first X-axis detection electrode, the second X-axis detection electrode, the third X-axis detection electrode and the fourth X-axis detection electrode are integrally symmetrical about the X axis and the Y axis.

15. The tri-axial accelerometer of claim 9,

the Y-axis accelerometer further comprises a longitudinal elastic beam arranged in the second space and positioned outside the Y mass block,

the Y mass block is connected with the Z mass block through the longitudinal elastic beam.

16. The tri-axial accelerometer of claim 15,

the Y-axis detection electrodes positioned in the Y mass block are four and are respectively a first Y-axis detection electrode, a second Y-axis detection electrode, a third Y-axis detection electrode and a fourth Y-axis detection electrode, wherein the first Y-axis detection electrode and the second Y-axis detection electrode are respectively positioned on the left side and the right side of the upper part in the Y mass block, and the third Y-axis detection electrode and the fourth Y-axis detection electrode are respectively positioned on the left side and the right side of the lower part in the Y mass block;

the two longitudinal elastic beams are respectively a first longitudinal elastic beam and a second longitudinal elastic beam, wherein the first longitudinal elastic beam and the second longitudinal elastic beam are respectively positioned at the left side and the right side of the Y mass block; the Y mass block is connected with the Z mass block through the first longitudinal elastic beam; the Y mass block is connected with the Z mass block through the second longitudinal elastic beam.

17. The tri-axial accelerometer of claim 16,

the first longitudinal elastic beam and the second longitudinal elastic beam are arranged in parallel to an X axis;

the Y-axis detection electrode is fixed on the substrate; the Y mass block and the longitudinal elastic beam are suspended above the substrate;

the first and second longitudinal elastic beams are symmetrical about an X axis; the first Y-axis detection electrode, the second Y-axis detection electrode, the third Y-axis detection electrode and the fourth Y-axis detection electrode are integrally symmetrical about the X axis and the Y axis.

18. The tri-axial accelerometer of claim 5,

the X-axis accelerometer and the Y-axis accelerometer are completely isolated, or the X-axis accelerometer and the Y-axis accelerometer share a mass block;

and the X mass block and the Z mass block are provided with through holes, blind holes, hollow or semi-hollow structures.