A three-axis accelerometer

Abstract

The present invention provides a three-axis accelerometer, which includes: a Z-axis accelerometer, which includes a Z mass block, a Z mass block anchor point, and a torsion beam, wherein the Z mass block is defined with a first space, a second space, and a third space, and the Z mass block anchor point is located in the third space; the torsion beam is located in the third space and is placed parallel to the Y axis, and the torsion beam connects 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 the mass of the Z mass block on the other side of the torsion beam, so that the Z mass block moves like a seesaw with the torsion beam as the axis; an X-axis accelerometer, which is located in the first space; and a Y-axis accelerometer, which is located in the second space. Compared with the prior art, the three-axis accelerometer of the present invention sets the X-axis accelerometer and the Y-axis accelerometer in the mass block of the Z-axis accelerometer, and its overall structure is reasonable and compact, which can save chip area and reduce costs.

Description

[Technical field]

[0001] The present invention relates to the technical field of micromechanical systems, and in particular to a three-axis accelerometer. [Background technology]

[0002] Micro-electromechanical accelerometer is an inertial device based on MEMS technology, which is used to measure the linear acceleration of an object. It has the characteristics of small size, high reliability, low cost, and suitable for mass production, so it has a broad market prospect. Its application fields include consumer electronics, aerospace, automobiles, medical equipment, weapons, etc.

[0003] At present, there are usually two ways to implement three-axis accelerometers. One is the patchwork method, which combines three single-axis structures or one dual-axis and one single-axis structure to achieve the measurement of three-axis acceleration. The second is to use a single structure to achieve the measurement of three-axis acceleration. In order to improve market competitiveness, it is necessary to further save chip area, reduce costs and improve sensitivity.

[0004] Therefore, it is urgent to propose a new technical solution to solve the above problems. [Summary of the invention]

[0005] One of the purposes of the present invention is to provide a three-axis accelerometer, the overall structure of which is reasonable and compact, which can save chip area and reduce costs.

[0006] According to one aspect of the present invention, the present invention provides a three-axis accelerometer, which includes: a Z-axis accelerometer, which can sense Z-axis acceleration, the Z-axis accelerometer includes a Z mass block, a Z mass block anchor point, and a torsion beam, the Z mass block is defined with a first space, a second space, and a third space, the Z mass block anchor point is located in the third space; the torsion beam is located in the third space and is placed parallel to the Y axis, the torsion beam connects the Z mass block anchor point and the Z mass block; the mass of the Z mass block located on one side of the torsion beam is connected to the Z mass block The mass of the block located on the other side of the torsion beam is different, so that the Z mass block moves like a seesaw with the torsion beam as the axis; an X-axis accelerometer, which can sense the X-axis acceleration, and the X-axis accelerometer is located in the first space; a Y-axis accelerometer, which can sense the Y-axis acceleration, and the Y-axis accelerometer is located in the second space, wherein the X-axis and the Y-axis are perpendicular to each other and define a plane where the 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.

[0007] Compared with the prior art, the three-axis accelerometer of the present invention arranges the X-axis accelerometer and the Y-axis accelerometer in the mass block of the Z-axis accelerometer, and its overall structure is reasonable and compact, which can save chip area and reduce costs.

Brief Description of the Drawings

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0009] Figure 1 is a schematic diagram of the overall structure of a three-axis accelerometer in a first embodiment of the present invention;

[0010] Figure 2 For the present invention Figure 1 A schematic diagram of the structure of an X-axis accelerometer in the three-axis accelerometer shown;

[0011] Figure 3 For the present invention Figure 1 A schematic diagram of the structure of a Y-axis accelerometer in the three-axis accelerometer shown;

[0012] Figure 4 For the present invention Figure 1 A schematic diagram of the structure of a Z-axis accelerometer in the three-axis accelerometer shown;

[0013] Figure 5 For the present invention Figure 1 The schematic diagram of the three-axis accelerometer shown is sensitive to the X-axis acceleration;

[0014] Figure 6 For the present invention Figure 1 The schematic diagram of the three-axis accelerometer shown is sensitive to the Y-axis acceleration;

[0015] Figure 7 For the present invention Figure 1 The schematic diagram of the three-axis accelerometer shown is sensitive to the Z-axis acceleration;

[0016] Figure 8 is a schematic diagram of the overall structure of a three-axis accelerometer in a second embodiment of the present invention;

[0017] Fig. 9 FIG. 4 is a schematic diagram of the overall structure of a three-axis accelerometer in a third embodiment of the present invention.

[0018] Among them, 1a-X mass block; 1b-Y mass block; 1c-Z mass block;

[0019] 2a-first transverse elastic beam; 2b-second transverse elastic beam; 2c-first longitudinal elastic beam; 2d-second longitudinal elastic beam; 2e-first torsion beam; 2f-second torsion beam;

[0020] 3a-first X-axis detection electrode; 3b-second X-axis detection electrode; 3c-third X-axis detection electrode; 3d-fourth X-axis detection electrode; 3e-first Y-axis detection electrode; 3f-second Y-axis detection electrode; 3g-third Y-axis detection electrode; 3h-fourth Y-axis detection electrode; 3i-first Z-axis detection electrode; 3j-second Z-axis detection electrode;

[0021] 4a-X mass block anchor point; 4b-Y mass block anchor point; 4c-Z mass block anchor point.

[0022] 5a-first transverse beam connecting arm; 5b-second transverse beam connecting arm; 5c-first longitudinal beam connecting arm; 5d-second longitudinal beam connecting arm;

[0023] 6a-transverse movable sparse teeth; 6b-transverse fixed sparse teeth; 6c-longitudinal movable sparse teeth; 6d-longitudinal fixed sparse teeth; 6e-torsion beam protection comb teeth.

[0024] 7a-first space; 7b-second space; 7c-third space;

[0025] Through hole - 8a. [Specific implementation method]

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments. Unless otherwise specified, the words "connected", "connected", and "connected" herein that indicate electrical connection all refer to direct or indirect electrical connection.

[0028] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore, cannot be understood as limiting the present invention. In the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", "coupled" and the like should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In view of the problems existing in the prior art, the present invention provides a three-axis accelerometer. Figure 1 As shown, it is a schematic diagram of the overall structure of a three-axis accelerometer in one embodiment of the present invention.

[0031] Figure 1 The three-axis accelerometer shown includes an X-axis accelerometer (not labeled), a Y-axis accelerometer (not labeled), and a Z-axis accelerometer (not labeled). The Z-axis accelerometer can sense Z-axis acceleration, and the Z-axis accelerometer includes a Z mass block 1c, and a first space 7a and a second space 7b are defined in the Z mass block 1c; the X-axis accelerometer can sense X-axis acceleration, and the X-axis accelerometer is located in the first space 7a; the Y-axis accelerometer can sense Y-axis acceleration, and the Y-axis accelerometer is located in the second space 7b.

[0032] In order to better illustrate the structure of the triaxial accelerometer shown in the present invention, a three-dimensional rectangular coordinate system can be established. Figure 1 In the embodiment shown, the X-axis and the Y-axis are perpendicular to each other and define the plane where the base of the three-axis accelerometer is located, and the Z-axis is perpendicular to the plane defined by the X-axis and the Y-axis. The three-dimensional rectangular coordinate system established by the X-axis, the Y-axis and the Z-axis is Figure 1 As shown in the figure, 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.

[0033] like Figure 1 and Figure 4As shown, the Z-axis accelerometer of the three-axis accelerometer further includes a Z mass block anchor point 4c, torsion beams 2e, 2f, a first Z-axis detection electrode 3i and a second Z-axis detection electrode 3j, and the Z mass block 1c is further defined with a third space 7c spaced from the first space 7a and the second space 7b; the Z mass block anchor point 4c is located in the third space 7c; the torsion beams 2e, 2f are located in the third space 7c, and the torsion beams 2e, 2f connect the Z mass block anchor point 4c and the Z mass block 1c; the mass of the Z mass block 1c on one side (or left side) of the torsion beams 2e, 2f is different from the mass of the Z mass block 1c on the other side (or right side) of the torsion beams 2e, 2f, so that the Z mass block 1c moves like a seesaw with the torsion beams 2e, 2f as the axis. The first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j are located below the Z mass block 1c and are symmetrically arranged on the left and right sides of the torsion beams 2e, 2f. When sensitive (or induced) to the Z-axis acceleration input, the Z mass block 1c will be twisted or pivoted (or similar to a seesaw motion) with the torsion beams 2e and 2f as the axis, and the first Z-axis detection electrode 3i detects the change in distance from the Z mass block 1c, and the second Z-axis detection electrode 3j detects the change in distance from the Z mass block 1c. Specifically, after being sensitive to the Z-axis acceleration rate, the capacitance of the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j increase and decrease respectively, and the difference between the two is the capacitance change caused by the Z-axis acceleration, thereby obtaining the input Z-axis acceleration rate.

[0034] like Figure 1 and Figure 4 As shown, the Z-axis accelerometer of the three-axis accelerometer also includes a torsion beam protection comb tooth 6e located in the third space 7c, and the torsion beam protection comb tooth 6e is connected to the Z mass block anchor point 4c or the Z mass block 1c, and the torsion beam protection comb tooth 6e is symmetrically distributed on the left and right sides of the torsion beam 2e, 2f to protect the torsion beam 2e, 2f.

[0035] exist Figure 1 and Figure 4In the specific embodiment shown, the torsion beams 2e and 2f are placed parallel to the Y-axis (or the extension direction of the torsion beams 2e and 2f is parallel to the Y-axis); there are two torsion beams 2e and 2f, namely the first torsion beam 2e and the second torsion beam 2f, wherein the first torsion beam 2e is located above the Z mass block anchor point 4c, and the first torsion beam 2e connects the Z mass block anchor point 4c and the Z mass block 1c; the second torsion beam 2f is located below the Z mass block anchor point 4c, and the second torsion beam 2f connects the Z mass block anchor point 4c and the Z mass block 1c. There are four pairs of torsion beam protection comb teeth 6e, among which two pairs of torsion beam protection comb teeth 6e are located above the Z mass block anchor point 4c, and are respectively located on the left and right sides of the first torsion beam 2e; the other two pairs of torsion beam protection comb teeth 6e are located below the Z mass block anchor point 4c, and are respectively located on the left and right sides of the second torsion beam 2f, one torsion beam protection comb tooth in each pair of torsion beam protection comb teeth 6e is connected to the Z mass block anchor point 4c, and the other torsion beam protection comb tooth is connected to the Z mass block 1c, wherein each torsion beam protection comb tooth 6e is placed parallel to the Y-axis.

[0036] exist Figure 1 and Figure 4 In the illustrated embodiment, the Z mass block anchor point 4c is fixedly disposed on a 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 to the Z mass block anchor point 4c via torsion beams 2e and 2f, and the Z mass block 1c and torsion beams 2e and 2f are suspended above the substrate; the torsion beam protection comb teeth 6e are suspended above the substrate.

[0037] exist Figure 1 and Figure 4 In the specific embodiment shown, 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; and the four pairs of torsion beam protection comb teeth 6e are symmetrically distributed about the X-axis and the Y-axis as a whole.

[0038] like Figure 1 and Figure 2As shown, the X-axis accelerometer of the three-axis accelerometer includes an X-axis mass block 1a and X-axis detection electrodes 3a, 3b, 3c, and 3d located in the X-axis mass block 1a, wherein the X-axis detection electrodes 3a, 3b, 3c, and 3d are provided with a plurality of transverse fixed comb teeth 6b parallel to the Y-axis, and the X-axis mass block 1a is provided with a plurality of transverse movable comb teeth 6a parallel to the Y-axis, wherein the plurality of transverse fixed comb teeth 6b in the X-axis detection electrodes 3a, 3b, 3c, and 3d and the plurality of transverse movable comb teeth 6a in the X-axis mass block 1a are arranged in an interdigitated manner to form an interdigitated capacitance. When the X-axis acceleration input is sensitive (or sensed), the X-mass block 1a moves along the X-axis, and the X-axis detection electrodes 3a, 3b, 3c, and 3d detect the change in distance from the X-mass block 1a. Specifically, compared with the capacitance of the X-axis detection electrodes 3a, 3b, 3c, and 3d before being sensitive to the X-axis acceleration, the capacitance of the X-axis detection electrodes 3a, 3b, 3c, and 3d after being sensitive to the X-axis acceleration increases or decreases, and the difference between the two is obtained to obtain the capacitance change caused by the X-axis acceleration, and then the input X-axis acceleration rate is obtained.

[0039] exist Figure 1 and Figure 2 In the specific embodiment shown, there are four X-axis detection electrodes located in the X-axis mass block 1a, namely 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 part of the X-axis 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 part of the X-axis mass block 1a.

[0040] like Figure 1 and Figure 2 As shown, the X-axis accelerometer also includes an X-mass block anchor point 4a, transverse elastic beam connecting arms 5a, 5b and transverse elastic beams 2a, 2b arranged in the X-mass block 1a, wherein the X-mass block anchor point 4a is connected to the X-mass block 1a via the transverse elastic beam connecting arms 5a, 5b and the transverse elastic beams 2a, 2b in sequence.

[0041] exist Figure 1 and Figure 2In the specific embodiment shown, there are two transverse elastic beam connecting arms 5a and 5b, which are the first transverse elastic beam connecting arm 5a and the second transverse elastic beam connecting arm 5b respectively; there are two transverse elastic beams 2a and 2b, which are the first transverse elastic beam 2a and the second transverse elastic beam 2b respectively, wherein the first transverse elastic beam 2a and the second transverse elastic beam 2b are respectively located on the left and right sides of the X mass block anchor point 4a; the first transverse elastic beam connecting arm 5a is located 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 located between the X mass block anchor point 4a and the second transverse elastic beam 2b; one end of the X mass block anchor point 4a is connected to the X mass block 1a via the first transverse elastic beam connecting arm 5a and the first transverse elastic beam 2a in sequence, and the other end of the X mass block anchor point 4a is connected to the X mass block 1a via the second transverse elastic beam connecting arm 5b and the second transverse elastic beam 2b in sequence.

[0042] exist Figure 1 and Figure 2 In the specific embodiment shown, the first transverse elastic beam connecting arm 5a and the second transverse elastic beam connecting arm 5b are placed parallel to the X-axis; the first transverse elastic beam 2a and the second transverse elastic beam 2b are placed parallel to the Y-axis (or the extension direction of the first transverse elastic beam 2a and the second transverse elastic beam 2b is parallel to the Y-axis); the first X-axis detection electrode 3a and the second X-axis detection electrode 3b are located above the X-mass anchor point 4a and between the first transverse elastic beam 2a and the second transverse elastic beam 2b; 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 2b.

[0043] exist Figure 1 and Figure 2 In the specific embodiment shown, the X-mass anchor 4a is fixed on the substrate; the X-axis detection electrodes 3a, 3b, 3c and 3d are fixed on the substrate; the X-mass 1a, the transverse elastic beam connecting arms 5a, 5b and the transverse elastic beams 2a, 2b are suspended above the substrate. The first transverse elastic beam connecting arm 5a and the second transverse elastic beam connecting arm 5b are symmetrical about the Y axis; the first transverse elastic beam 2a and the second transverse elastic 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 about the X axis and the Y axis as a whole.

[0044] like Figure 1 and Figure 3As shown, 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, wherein the Y-axis detection electrodes 3e, 3f, 3g, and 3h are provided with a plurality of longitudinal fixed comb teeth 6d parallel to the X-axis, and the Y mass block 1b is provided with a plurality of longitudinal movable comb teeth 6c parallel to the X-axis, 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 a forked arrangement to form a forked capacitance. When sensitive (or induced) to the Y-axis acceleration input, the Y mass block 1b will move along the Y-axis, and the Y-axis detection electrodes 3e, 3f, 3g, 3h detect the change in distance from the Y mass block 1b. Specifically, compared with the capacitance of the Y-axis detection electrodes 3e, 3f, 3g, 3h before being sensitive to the Y-axis acceleration, the capacitance of the Y-axis detection electrodes 3e, 3f, 3g, 3h after being sensitive to the Y-axis acceleration increases or decreases, and the difference between the two is obtained to obtain the capacitance change caused by the Y-axis acceleration, and then the input Y-axis acceleration rate is obtained.

[0045] exist Figure 1 and Figure 3 In the specific embodiment shown, there are four Y-axis detection electrodes located in the Y mass block 1b, namely 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 of 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 of the Y mass block 1b.

[0046] like Figure 1 and Figure 3 As shown, the Y-axis accelerometer also includes a Y-mass block anchor point 4b, longitudinal elastic beam connecting arms 5c, 5d and longitudinal elastic beams 2c, 2d, which are arranged in the Y-mass block 1b, wherein the Y-mass block anchor point 4b is connected to the Y-mass block 1b via the longitudinal elastic beam connecting arms 5c, 5d and the longitudinal elastic beams 2c, 2d in sequence.

[0047] exist Figure 1 and Figure 3In the specific embodiment shown, there are two longitudinal elastic beam connecting arms 5c and 5d, which are the first longitudinal elastic beam connecting arm 5c and the second longitudinal elastic beam connecting arm 5d respectively; there are two longitudinal elastic beams 2c and 2d, which are the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d respectively, wherein the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are respectively located at the upper and lower ends of the Y mass block anchor point 4b; the first longitudinal elastic beam connecting arm 5c is located 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 located between the Y mass block anchor point 4b and the second longitudinal elastic beam 2d; one end of the Y mass block anchor point 4b is connected to the Y mass block 1b via the first longitudinal elastic beam connecting arm 5c and the first longitudinal elastic beam 2c in sequence, and the other end of the Y mass block anchor point 4b is connected to the Y mass block 1b via the second longitudinal elastic beam connecting arm 5d and the second longitudinal elastic beam 2d in sequence.

[0048] exist Figure 1 and Figure 3 In the specific embodiment shown, the first longitudinal elastic beam connecting arm 5c and the second longitudinal elastic beam connecting arm 5d are placed parallel to the Y-axis; the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are placed parallel to the X-axis (or the extension 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 located 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 2d; 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 block anchor point 4b, and between the first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d.

[0049] exist Figure 1 and Figure 3 In the specific embodiment shown, the Y mass anchor 4b is fixed on the substrate; the Y-axis detection electrodes 3e, 3f, 3g, 3h are fixed on the substrate; the Y mass 1b, the longitudinal elastic beam connecting arms 5c, 5d and the longitudinal elastic beams 2c, 2d are suspended above the substrate. Among them, the first longitudinal elastic beam connecting arm 5c and the second longitudinal elastic 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 symmetrical about the X-axis and the Y-axis as a whole.

[0050] exist Figure 1 In the embodiment shown, the X-axis accelerometer and the Y-axis accelerometer are located in the Z mass block 1c and are located on the left and right sides of the torsion beams 2e and 2f respectively. Figure 1In the illustrated embodiment, a certain number of through holes, blind holes, hollow or semi-hollow structures may be provided 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.

[0051] In order to ensure that the mass of the Z mass block 1c on one side (or left side) of the torsion beam 2e, 2f is different from the mass of the Z mass block 1c on the other side (or right side) of the torsion beam 2e, 2f, implementation method 1: the Z mass block 1c is symmetrically distributed along the torsion beam 2e, 2f, so that the number of through holes 8a, blind holes, hollow or semi-hollow structures provided on the Z mass block 1c on one side of the torsion beam 2e, 2f is different from the number of through holes, blind holes, hollow or semi-hollow structures provided on the Z mass block 1c on the other side of the torsion beam. For example, Figure 1 and Figure 4 In the specific embodiment shown, the Z mass block 1c is symmetrically distributed along the torsion beams 2e and 2f, which can resist external interference and effectively improve its reliability; a through hole 8a is provided on the Z mass block 1c on one side of the torsion beams 2e and 2f, and no through hole is provided on the Z mass block 1c on the right side of the torsion beams 2e and 2f, so that the mass of the Z mass block 1c on the left side of the torsion beams 2e and 2f is greater than the mass of the Z mass block 1c on the right side of the torsion beams 2e and 2f.

[0052] In order to ensure that the mass of the Z mass block 1c on one side (or left side) of the torsion beam 2e, 2f is different from the mass of the Z mass block 1c on the other side (or right side) of the torsion beam 2e, 2f, implementation method 2: the size of the Z mass block 1c on one side (or left side) of the torsion beam 2e, 2f is different from the size of the Z mass block 1c on the other side (or right side) of the torsion beam 2e, 2f. For details, please refer to the attached Figure 8 .

[0053] Please refer to Fig. 9 As shown, it is a schematic diagram of the overall structure of the three-axis accelerometer in the third embodiment of the present invention. Figure 1 The three-axis accelerometers shown differ only in that: Fig. 9 The X-axis accelerometer shown is not provided with an X-mass anchor point 4a and transverse elastic beam connecting arms 5a, 5b, and the X-mass 1a is connected to the Z-mass 1c via transverse elastic beams 2a, 2b; Fig. 9 The Y-axis accelerometer shown is not provided with a Y-mass anchor point 4b and longitudinal elastic beam connecting arms 5c, 5d, and the Y-mass block 1b is connected to the Z-mass block 1c through longitudinal elastic beams 2c, 2d.

[0054] exist Fig. 9In the illustrated embodiment, the transverse elastic beams 2a, 2b are disposed in the first space 7a and outside the X mass block 1a, and the X mass block 1a is connected to the Z mass block 1c via the transverse elastic beams 2a, 2b.

[0055] exist Fig. 9 In the specific embodiment shown, there are two transverse elastic beams 2a and 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 on the left and right sides of the X mass block 1a; the X mass block 1a is connected to the Z mass block 1c through the first transverse elastic beam 2a; the X mass block 1a is connected to the Z mass block 1c through the second transverse elastic beam 2b. The first transverse elastic beam 2a and the second transverse elastic beam 2b are placed parallel to the Y axis (or the extension direction of the first transverse elastic beam 2a and the second transverse elastic beam 2b is parallel to the Y axis), and the first transverse elastic beam 2a and the second transverse elastic beam 2b are symmetrical about the Y axis.

[0056] exist Fig. 9 In the illustrated embodiment, the longitudinal elastic beams 2c, 2d are disposed in the second space 7b and outside the Y mass block 1b, and the Y mass block 1b is connected to the Z mass block 1c via the longitudinal elastic beams 2c, 2d.

[0057] exist Fig. 9 In the specific embodiment shown, 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 on the left and right sides of the Y mass block 1b; the Y mass block 1b is connected to the Z mass block 1c through the first longitudinal elastic beam 2c; the Y mass block 1b is connected to the Z mass block 1c through the second longitudinal elastic beam 2d. The first longitudinal elastic beam 2c and the second longitudinal elastic beam 2d are placed parallel to the X-axis (or the extension 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 about the Y-axis.

[0058] In summary, in Figure 1 , Figure 2 and Figure 3 In the embodiment shown, the X-axis accelerometer is independently arranged in the first space 7a inside the Z mass block 1c, that is, the X-axis accelerometer and the Z mass block 1c are independent of each other and not connected; the Y-axis accelerometer is independently arranged in the second space 7b inside the Z mass block 1c, that is, the Y-axis accelerometer and the Z mass block 1c are independent of each other and not connected. Fig. 9In the illustrated embodiment, the X-axis accelerometer and the Y-axis accelerometer are each connected to the Z mass block 1c via elastic beams 2a-2d.

[0059] The present invention is described below Figure 1 The detection principle of the three-axis accelerometer shown.

[0060] 1. X-axis accelerometer detection principle

[0061] Please refer to Figure 5 As shown, it is the present invention Figure 1 The schematic diagram of the three-axis accelerometer shown is sensitive to the X-axis acceleration.

[0062] The X-axis detection electrodes 3a, 3b, 3c, and 3d are provided with a plurality of transverse fixed comb teeth 6b parallel to the Y-axis, and the X-mass block 1a is provided with a plurality of transverse movable comb teeth 6a parallel to the Y-axis. When sensitive to (or induction of) the X-axis acceleration input, the X-mass block 1a will drive the plurality of transverse movable comb teeth 6a to move along the X-axis, and the transverse fixed comb teeth 6b in the X-axis detection electrodes 3a, 3b, 3c, and 3d will be sensitive to the change in distance from the transverse movable comb teeth 6a in the X-mass block 1a, and the capacitance of the two will change. By detecting the capacitance change of the transverse fixed comb teeth 6b in the X-axis detection electrodes 3a, 3b, 3c, and 3d, the measurement of the X-axis acceleration is achieved. It can also be said that the X-axis detection electrodes 3a, 3b, 3c, 3d detect the change in distance from the X mass block 1a. Specifically, compared with the capacitance of the X-axis detection electrodes 3a, 3b, 3c, 3d before being sensitive to the X-axis acceleration, the capacitance of the X-axis detection electrodes 3a, 3b, 3c, 3d after being sensitive to the X-axis acceleration increases or decreases, and the difference between the two is obtained to obtain the capacitance change caused by the X-axis acceleration, and then the input X-axis acceleration rate is obtained.

[0063] It should be noted that Figure 5 It is only shown by way of example that when the X-mass block 1 a is sensitive to the X-axis acceleration input, one movement direction of the X-mass block 1 a along the X-axis is shown.

[0064] 2. Y-axis accelerometer detection principle

[0065] Please refer to Figure 6 As shown, it is the present invention Figure 1 The schematic diagram of the three-axis accelerometer shown is sensitive to Y-axis acceleration.

[0066] The Y-axis detection electrodes 3e, 3f, 3g, and 3h are provided with a plurality of longitudinal fixed comb teeth 6d parallel to the X-axis, and the Y mass block 1b is provided with a plurality of longitudinal movable comb teeth 6c parallel to the X-axis. When sensitive to (or induction of) Y-axis acceleration input, the Y mass block 1b will drive the plurality of longitudinal movable comb teeth 6c to move along the Y-axis, and the longitudinal fixed comb teeth 6d in the Y-axis detection electrodes 3e, 3f, 3g, and 3h will be sensitive to the change in distance from the longitudinal movable comb teeth 6c in the Y mass block 1c, and the capacitance of the two will change. By detecting the capacitance change of the longitudinal movable comb teeth 6c in the Y-axis detection electrodes 3e, 3f, 3g, and 3h, the measurement of the Y-axis acceleration is achieved. It can also be said that the Y-axis detection electrodes 3e, 3f, 3g, and 3h detect the change in distance from the Y mass block 1b. Specifically, compared with the capacitance of the Y-axis detection electrodes 3e, 3f, 3g, and 3h before being sensitive to the Y-axis acceleration, the capacitance of the Y-axis detection electrodes 3e, 3f, 3g, and 3h after being sensitive to the Y-axis acceleration increases or decreases, and the difference between the two is the capacitance change caused by the Y-axis acceleration, and then the input Y-axis acceleration rate is obtained.

[0067] It should be noted that Figure 6 It is only given as an example that when the Y-axis acceleration input is sensed, the Y-mass block 1 b moves in one direction along the Y-axis.

[0068] 3. Z-axis accelerometer detection principle

[0069] Please refer to Figure 7 As shown, it is the present invention Figure 1 The schematic diagram of the three-axis accelerometer shown is sensitive to Z-axis acceleration.

[0070] The first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j are located below the Z mass block 1c and are symmetrically arranged on the left and right sides of the torsion beams 2e and 2f. When sensitive (or inductive) to the Z-axis acceleration input, the Z mass block 1c will be twisted (or similar to a seesaw motion) with the torsion beams 2e and 2f as the axis, and the distance between the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j on both sides and the Z mass block 1c will change, so that the capacitance of the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j will change, and the Z-axis acceleration can be measured by detecting the capacitance change of the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j. It can also be said that the first Z-axis detection electrode 3i detects the change in distance from the Z mass block 1c, and the second Z-axis detection electrode 3j detects the change in distance from the Z mass block 1c. Specifically, after being sensitive to the Z-axis acceleration rate, the capacitance of the first Z-axis detection electrode 3i and the second Z-axis detection electrode 3j increase and decrease respectively, and the difference between the two is used to obtain the capacitance change caused by the Z-axis acceleration, thereby obtaining the input Z-axis acceleration rate.

[0071] It should be noted that Figure 7 It is only shown by way of example that when the Z-axis acceleration input is sensed, the Z mass block 1c moves in one direction with the torsion beams 2e and 2f as the axis.

[0072] In summary, the three-axis accelerometer provided by the present invention includes an X-axis accelerometer (unlabeled), a Y-axis accelerometer (unlabeled) and a Z-axis accelerometer (unlabeled). Among them, the Z-axis accelerometer can sense the Z-axis acceleration, and the Z-axis accelerometer includes a Z mass block 1c, and the Z mass block 1c defines a first space 7a and a second space 7b; the X-axis accelerometer can sense the X-axis acceleration, and the X-axis accelerometer is located in the first space 7a; the Y-axis accelerometer can sense the Y-axis acceleration, and the Y-axis accelerometer is located in the second space 7b. In this way, the overall architecture of the three-axis accelerometer provided by the present invention is reasonable and compact, which can save chip area and reduce costs.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0074] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify and vary the above embodiments within the scope of the present invention.

Claims

1. A three-axis accelerometer, characterized in that: It includes: A Z-axis accelerometer, which can sense Z-axis acceleration, 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 located in the third space; the torsion beam is located in the third space and is placed parallel to the Y axis, and the torsion beam connects 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 the mass of the Z mass block on the other side of the torsion beam, so that the Z mass block moves like a seesaw with the torsion beam as the axis; An X-axis accelerometer, which can sense X-axis acceleration, and the X-axis accelerometer is located in the first space; a Y-axis accelerometer capable of sensing Y-axis acceleration, wherein the Y-axis accelerometer is located in the second space, The X-axis and the Y-axis are perpendicular to each other and define a plane where the 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 three-axis accelerometer according to claim 1, characterized in that: The Z-axis accelerometer further includes a first Z-axis detection electrode and a second Z-axis detection electrode. The first Z-axis detection electrode and the second Z-axis detection electrode are located below the Z mass block and are symmetrically arranged on both sides of the torsion beam; The X-axis accelerometer is located on one side of the torsion beam, and the Y-axis accelerometer is located on the other side of the torsion beam; The X-axis accelerometer is independently arranged in a first space inside the Z mass block, and the Y-axis accelerometer is independently arranged in a second space inside the Z mass block, or the X-axis accelerometer and the Y-axis accelerometer are each connected to the Z mass block through an elastic beam; When the Z-axis acceleration input is sensitive, the Z mass block will undergo a seesaw-like motion with the torsion beam as the axis. The first Z-axis detection electrode detects the change in distance from the Z mass block, and the second Z-axis detection electrode detects the change in distance from the Z mass block. After being sensitive to the Z-axis acceleration rate, the capacitance of the first Z-axis detection electrode and the second Z-axis detection electrode increase and decrease respectively. The difference between the two is used to obtain the capacitance change caused by the Z-axis acceleration, and then the input Z-axis acceleration rate is obtained.

3. The three-axis accelerometer according to claim 2, characterized in that: The Z-axis accelerometer of the three-axis accelerometer further includes a torsion beam protection comb tooth located in the third space, the torsion beam protection comb tooth is connected to the Z mass block anchor point or the Z mass block, and the torsion beam protection comb teeth are symmetrically distributed on the left and right sides 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 block and the torsion beam are suspended above the substrate; and the torsion beam protection mechanism is suspended above the substrate.

4. The three-axis accelerometer according to claim 3, characterized in that: There are two torsion beams, namely a first torsion beam and a second torsion beam, wherein the first torsion beam is located above the anchor point of the Z mass block, and the first torsion beam connects the Z mass block anchor point and the Z mass block; the second torsion beam is located below the anchor point of the Z mass block, and the second torsion beam connects the Z mass block anchor point and the Z mass block; There are four pairs of torsion beam protection comb teeth, wherein two pairs of torsion beam protection comb teeth are located above the anchor point of the Z mass block and are respectively located on both sides of the first torsion beam; the other two pairs of torsion beam protection comb teeth are located below the anchor point of the Z mass block and are respectively located on both sides of the second torsion beam, one torsion beam protection comb tooth in each pair of torsion beam protection comb teeth is connected to the anchor point of the Z mass block, and the other torsion beam protection comb tooth is connected to the Z mass block; The first torsion beam and the second torsion beam are symmetrically distributed about the X-axis; the first Z-axis detection electrode and the second Z-axis detection electrode are symmetrically distributed about the Y-axis; and the four torsion beam protection mechanisms are symmetrically distributed about the X-axis and the Y-axis as a whole.

5. The three-axis accelerometer according to claim 2, characterized in that: The X-axis accelerometer of the three-axis accelerometer includes an X-mass block and an X-axis detection electrode located in the X-mass block. When the X-axis acceleration input is sensitive, the X-mass block moves along the X-axis, and the X-axis detection electrode detects the change in distance from the X-mass block. Compared with the capacitance of the X-axis detection electrode before the X-axis acceleration is sensitive, the capacitance of the X-axis detection electrode after the X-axis acceleration is increased or decreased. The difference between the two is obtained to obtain the capacitance change caused by the X-axis acceleration, and then the input X-axis acceleration rate is obtained.

6. The three-axis accelerometer according to claim 5, characterized in that: The X-axis accelerometer is independently arranged in the first space inside the Z mass block, The X-axis accelerometer further includes an X-mass anchor point, a transverse elastic beam connecting arm and a transverse elastic beam disposed in the X-mass. The X mass block anchor point is connected to the X mass block via the transverse elastic beam connecting arm and the transverse elastic beam in sequence.

7. The three-axis accelerometer according to claim 6, characterized in that: There are four X-axis detection electrodes located in the X mass block, namely 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 located on the left and right sides of the upper part of the X mass block, respectively, and the third X-axis detection electrode and the fourth X-axis detection electrode are located on the left and right sides of the lower part of the X mass block, respectively; There are two transverse elastic beam connecting arms, namely a first transverse elastic beam connecting arm and a second transverse elastic beam connecting arm; there are two transverse elastic beams, 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 located on the left and right sides of the X mass block anchor point; the first transverse elastic beam connecting arm is located between the X mass block anchor point and the first transverse elastic beam, and the second transverse elastic beam connecting arm is located between the X mass block anchor point and the second transverse elastic beam; one end of the X mass block anchor point is connected to the X mass block via the first transverse elastic beam connecting arm and the first transverse elastic beam in sequence, and the other end of the X mass block anchor point is connected to the X mass block via the second transverse elastic beam connecting arm and the second transverse elastic beam in sequence.

8. The three-axis accelerometer according to claim 7, characterized in that: The first transverse elastic beam connecting arm and the second transverse elastic beam connecting arm are placed parallel to the X-axis; the first transverse elastic beam and the second transverse elastic beam are placed parallel to the Y-axis; the first X-axis detection electrode and the second X-axis detection electrode are located above the X-mass 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 located below the X-mass anchor point and between the first transverse elastic beam and the second transverse elastic beam; The X-mass anchor is fixed on the substrate; the X-axis detection electrode is fixed on the substrate; the X-mass, 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 about the Y axis; the first transverse elastic beam and the second transverse elastic beam are symmetrical about the 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 symmetrical about the X axis and the Y axis as a whole.

9. The three-axis accelerometer according to claim 2, characterized in that: The Y-axis accelerometer of the three-axis accelerometer includes a Y-mass block and a Y-axis detection electrode located in the Y-mass block. When the Y-axis acceleration input is sensitive, the Y mass block will move along the Y-axis, and the Y-axis detection electrode detects the change in distance from the Y mass block. Compared with the capacitance of the Y-axis detection electrode before the Y-axis acceleration is sensitive, the capacitance of the Y-axis detection electrode after the Y-axis acceleration is increased or decreased. The difference between the two is the capacitance change caused by the Y-axis acceleration, and then the input Y-axis acceleration rate is obtained.

10. The three-axis accelerometer according to claim 9, characterized in that: The Y-axis accelerometer is independently arranged in the second space inside the Z mass block, The Y-axis accelerometer further includes a Y mass block anchor point, a longitudinal elastic beam connecting arm and a longitudinal elastic beam arranged in the Y mass block. The Y mass block anchor point is connected to the Y mass block via the longitudinal elastic beam connecting arm and the longitudinal elastic beam in sequence.

11. The three-axis accelerometer according to claim 10, characterized in that: There are four Y-axis detection electrodes located in the Y mass block, namely 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 located at the upper and lower ends of the left side of the Y mass block, and the third Y-axis detection electrode and the fourth Y-axis detection electrode are respectively located at the upper and lower ends of the right side of the Y mass block; There are two longitudinal elastic beam connecting arms, namely a first longitudinal elastic beam connecting arm and a second longitudinal elastic beam connecting arm; there are two longitudinal elastic beams, namely 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 located at the upper and lower ends of the Y mass block anchor point; the first longitudinal elastic beam connecting arm is located between the Y mass block anchor point and the first longitudinal elastic beam, and the second longitudinal elastic beam connecting arm is located between the Y mass block anchor point and the second longitudinal elastic beam; one end of the Y mass block anchor point is connected to the Y mass block via 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 to the Y mass block via the second longitudinal elastic beam connecting arm and the second longitudinal elastic beam in sequence.

12. The three-axis accelerometer according to claim 11, characterized in that: The first longitudinal elastic beam connecting arm and the second longitudinal elastic beam connecting arm are placed parallel to the Y axis; the first longitudinal elastic beam and the second longitudinal elastic beam are placed parallel to the X axis; the first Y axis detection electrode and the second Y axis detection electrode are located on the left side of the Y mass block anchor point and 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 located on the right side of the Y mass block anchor point and between the first longitudinal elastic beam and the second longitudinal elastic beam; The Y mass anchor 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 the X-axis; the first longitudinal elastic beam and the second longitudinal elastic beam are symmetrical about the 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 symmetrical about the X-axis and the Y-axis as a whole.

13. The three-axis accelerometer according to claim 5, characterized in that: The X-axis accelerometer further includes a transverse elastic beam disposed in the first space and located outside the X mass block, The X mass block is connected to the Z mass block via the transverse elastic beam.

14. The three-axis accelerometer according to claim 13, characterized in that: There are four X-axis detection electrodes located in the X mass block, namely 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 located on the left and right sides of the upper part of the X mass block, respectively, and the third X-axis detection electrode and the fourth X-axis detection electrode are located on the left and right sides of the lower part of the X mass block, respectively; There are two transverse elastic beams, 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 located on the left and right sides of the X mass block; the X mass block is connected to the Z mass block through the first transverse elastic beam; the X mass block is connected to the Z mass block through the second transverse elastic beam; The first transverse elastic beam and the second transverse elastic beam are placed 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 transverse elastic beam and the second transverse elastic beam are symmetrical about the 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 symmetrical about the X axis and the Y axis as a whole.

15. The three-axis accelerometer according to claim 9, characterized in that: The Y-axis accelerometer further includes a longitudinal elastic beam disposed in the second space and located outside the Y mass block, The Y mass block is connected to the Z mass block via the longitudinal elastic beam.

16. The three-axis accelerometer according to claim 15, characterized in that: There are four Y-axis detection electrodes located in the Y mass block, namely 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 located on the left and right sides of the upper part of the Y mass block, respectively, and the third Y-axis detection electrode and the fourth Y-axis detection electrode are located on the left and right sides of the lower part of the Y mass block, respectively; There are two longitudinal elastic beams, namely 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 located on the left and right sides of the Y mass block; the Y mass block is connected to the Z mass block through the first longitudinal elastic beam; the Y mass block is connected to the Z mass block through the second longitudinal elastic beam.

17. The three-axis accelerometer according to claim 16, characterized in that: The first longitudinal elastic beam and the second longitudinal elastic beam are placed parallel to the 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 longitudinal elastic beam and the second longitudinal elastic beam are symmetrical about the 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 symmetrical about the X-axis and the Y-axis as a whole.

18. The three-axis accelerometer according to claim 5, characterized in that: The X mass block, the Y mass block and the Z mass block are provided with through holes, blind holes, hollow or semi-hollow structures.

19. The three-axis accelerometer according to claim 18, characterized in that: The Z mass blocks are symmetrically distributed along the torsion beam, and the number of through holes, blind holes, hollow or semi-hollow structures provided on one side of the torsion beam of the Z mass blocks is different from the number of through holes, blind holes, hollow or semi-hollow structures provided on the other side of the torsion beam of the Z mass blocks; or The size of the Z mass at one side of the torsion beam is different from the size of the Z mass at the other side of the torsion beam.

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