Acceleration sensor

Abstract

An acceleration sensor, which comprises a first acceleration detection unit (5), a second acceleration detection unit (6), a substrate, a connecting arm (4), a first anchor point (11), a first elastic element (2), and a second elastic element (3). The first acceleration detection unit (5) is used for detecting an acceleration along an out-of-plane Z-axis direction. The first acceleration detection unit (5) comprises a first seesaw unit (51) and a second seesaw unit (52). The first seesaw unit (51) and the second seesaw unit (52) are oppositely arranged, and the first seesaw unit (51) and the second seesaw unit (52) enclose to form an annular structure. The second acceleration detection unit (6) is used for detecting an acceleration along an in-plane X-axis direction and / or an in-plane Y-axis direction. The annular structure surrounds an outer side of the second acceleration detection unit (6). The connecting arm (4) is fixed to the substrate by means of the first anchor point (11). The connecting arm (4) is located between the first acceleration detection unit (5) and the second acceleration detection unit (6). Thus, technical effects of a reasonable structural design and stronger anti-interference capability are achieved.

Description

An acceleration sensor Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to an acceleration sensor. Background Art

[0002] Acceleration sensors include one or more proof masses for detecting acceleration. For example, some acceleration sensors include a proof mass configured to move within a plane to detect acceleration in the plane of the proof mass, and the proof mass configured to move out of plane to detect acceleration perpendicular to the plane of the proof mass. Acceleration can be detected using a capacitive sensor coupled to the proof mass.

[0003] Currently, when an accelerometer detects in-plane acceleration and out-of-plane acceleration, the in-plane detection structure and the out-of-plane detection structure are fixed to the substrate respectively, which makes the overall structure of the accelerometer significantly affected by factors such as stress, which is not conducive to improving the anti-interference ability of the accelerometer. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art and provide a new technical solution for an acceleration sensor.

[0005] According to one aspect of the present invention, there is provided an acceleration sensor, comprising:

[0006] a first acceleration detection unit, the first acceleration detection unit being configured to detect acceleration along an out-of-plane Z-axis direction; the first acceleration detection unit comprising a first seesaw unit and a second seesaw unit, the first seesaw unit and the second seesaw unit being disposed opposite to each other and forming a ring structure;

[0007] a second acceleration detection unit, the second acceleration detection unit being configured to detect acceleration along an in-plane X-axis direction and / or an in-plane Y-axis direction; the annular structure surrounding an outer side of the second acceleration detection unit;

[0008] A base, a connecting arm and a first anchor point, wherein the first anchor point is located in the middle of the base, and the connecting arm is fixed to the base through the first anchor point; the connecting arm is located between the first acceleration detection unit and the second acceleration detection unit;

[0009] a first elastic member and a second elastic member, wherein the first acceleration detection unit is connected to the connecting arm via the first elastic member; and the second acceleration detection unit is connected to the connecting arm via the second elastic member;

[0010] The out-of-plane Z-axis direction, the in-plane X-axis direction, and the in-plane Y-axis direction are perpendicular to each other.

[0011] Optionally, the first acceleration detection unit further includes an out-of-plane displacement detection unit;

[0012] The middle portion of the connecting arm close to the second acceleration detection unit is fixed to the first anchor point;

[0013] The first seesaw unit is elastically connected to the first end of the connecting arm, and the second seesaw unit is elastically connected to the second end of the connecting arm; the first seesaw unit and the second seesaw unit are symmetrically distributed along the symmetry axis of the acceleration sensor; the first seesaw unit forms two first seesaw structures on both sides of the symmetry axis, and the two first seesaw structures rotate along the first rotation axis; the second seesaw unit forms two second seesaw structures on both sides of the symmetry axis, and the two second seesaw structures rotate along the second rotation axis; the first rotation axis is arranged parallel to the second rotation axis, and the first rotation axis and the second rotation axis are both perpendicular to the symmetry axis;

[0014] The out-of-plane displacement detection unit is provided on both the first seesaw unit and the second seesaw unit.

[0015] Optionally, a first groove is provided on the outer side of the first seesaw unit, and a second groove is provided on the inner side of the second seesaw unit, part of the first seesaw unit is embedded in the second groove and part of the second seesaw unit is embedded in the first groove to form a nested structure, and the nested structure is located between the first rotating shaft and the second rotating shaft.

[0016] Optionally, the acceleration sensor further includes a first detection mass block and a second detection mass block;

[0017] Each of the first seesaw structures includes a first sub-rotating portion and a second sub-rotating portion, the first sub-rotating portion and the second sub-rotating portion are respectively located on opposite sides of the first rotating shaft, and a first groove is provided on an outer side of the second sub-rotating portion; each of the second seesaw structures includes a third sub-rotating portion and a fourth sub-rotating portion, the third sub-rotating portion and the fourth sub-rotating portion are respectively located on opposite sides of the second rotating shaft, and a second groove is provided on an inner side of the third sub-rotating portion;

[0018] The first detection mass block is located on the first sub-rotation portion, the second detection mass block is located on the fourth sub-rotation portion, and the first detection mass block and the second detection mass block are symmetrically arranged.

[0019] Optionally, the acceleration sensor further includes a coupling beam, which extends in a direction perpendicular to the symmetry axis, and one end of the coupling beam is connected to the second sub-rotation part, and the other end of the coupling beam is connected to the third sub-rotation part.

[0020] Optionally, the second acceleration detection unit is used to detect acceleration along the in-plane X-axis direction, the second elastic member is an X-axis single-degree-of-freedom spring distributed along the in-plane Y-axis direction, and the second acceleration detection unit is fixed to the connecting arm through the X-axis single-degree-of-freedom spring;

[0021] The second acceleration detection unit includes a first mass block and a first capacitor group; the first mass block is provided with first mounting grooves distributed along the Y-axis direction in the plane, and each first mounting groove is provided with a first capacitor group;

[0022] The first capacitor group includes a first positive fixed electrode and a first negative fixed electrode, and the first positive fixed electrode and the first negative fixed electrode are distributed along the Y-axis direction in the plane; the side of the first positive fixed electrode away from the first negative fixed electrode forms a first differential detection capacitor with the first mass block, and the side of the first negative fixed electrode away from the first positive fixed electrode forms a second differential detection capacitor with the first mass block.

[0023] Optionally, the second acceleration detection unit is used to detect acceleration along the in-plane Y-axis direction, the second elastic member is a Y-axis single-degree-of-freedom spring distributed along the in-plane X-axis direction, and the second acceleration detection unit is fixed to the connecting arm through the Y-axis single-degree-of-freedom spring;

[0024] The second acceleration detection unit includes a second mass block and a second capacitor group; the middle portion of the second mass block is provided with second mounting grooves distributed along the in-plane X-axis direction, and each second mounting groove is provided with a second capacitor group;

[0025] The second capacitor group includes a second positive fixed electrode and a second negative fixed electrode, and the second positive fixed electrode and the second negative fixed electrode are distributed along the in-plane X-axis direction; the side of the second positive fixed electrode away from the second negative fixed electrode and the second mass block form a third differential detection capacitor, and the side of the second negative fixed electrode away from the second positive fixed electrode and the second mass block form a fourth differential detection capacitor.

[0026] Optionally, the annular structure surrounds the outer side of the connecting arm;

[0027] The connecting arm is provided with a receiving groove for installing the second acceleration detection unit;

[0028] The first anchor point is located at the center of the connecting arm.

[0029] Optionally, the two receiving grooves are symmetrically arranged.

[0030] Optionally, each of the accommodating grooves is provided with a second acceleration detection unit;

[0031] One of the second acceleration detection units is used to detect acceleration in the X-axis direction within the plane; the other of the second acceleration detection units is used to detect acceleration in the Y-axis direction within the plane.

[0032] A technical effect of the present invention is:

[0033] In an embodiment of the present application, the first acceleration detection unit is used to detect acceleration along the out-of-plane Z-axis direction; the first acceleration detection unit includes a first seesaw unit and a second seesaw unit, the first seesaw unit and the second seesaw unit are arranged opposite to each other, and the two together form an annular structure. The second acceleration detection unit is used to detect acceleration along the in-plane X-axis direction and / or the in-plane Y-axis direction; the annular structure surrounds the outside of the second acceleration detection unit. The first anchor point is located in the middle of the base, and the connecting arm is fixed to the base through the first anchor point; the connecting arm is located between the first acceleration detection unit and the second acceleration detection unit; the first acceleration detection unit is connected to the connecting arm through a first elastic member; the second acceleration detection unit is connected to the connecting arm through a second elastic member.

[0034] Therefore, the first anchor point is set at the center of the acceleration sensor structure, and the first acceleration detection and the second acceleration detection share the first anchor point through the connecting arm, so that the overall structure of the acceleration sensor is less affected by factors such as stress, thereby significantly improving the anti-interference ability of the acceleration sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a schematic structural diagram of an acceleration sensor according to a first embodiment of the present invention;

[0036] 2 is a schematic diagram of a detection mode in the in-plane X-axis direction of the acceleration sensor according to the first embodiment of the present invention;

[0037] 3 is a schematic diagram of the detection mode of the acceleration sensor in the out-of-plane Z-axis direction according to the first embodiment of the present invention;

[0038] 4 is a schematic diagram of the parasitic modes of the acceleration sensor in the out-of-plane Z-axis direction according to the first embodiment of the present invention;

[0039] FIG5 is a schematic structural diagram of a coupling beam of an acceleration sensor according to the first embodiment of the present invention;

[0040] FIG6 is a schematic structural diagram of an acceleration sensor according to a second embodiment of the present invention;

[0041] 7 is a schematic diagram of a detection mode in the in-plane X-axis direction of the acceleration sensor according to the second embodiment of the present invention;

[0042] 8 is a schematic diagram of the detection mode of the acceleration sensor in the out-of-plane Z-axis direction according to the second embodiment of the present invention;

[0043] 9 is a schematic diagram of the out-of-plane parasitic modes in the Z-axis direction of the acceleration sensor according to the second embodiment of the present invention;

[0044] FIG10 is a schematic structural diagram of an acceleration sensor according to a third embodiment of the present invention;

[0045] 11 is a schematic diagram of the detection mode of the acceleration sensor in the Y-axis direction in the plane according to the third embodiment of the present invention;

[0046] 12 is a schematic diagram of the detection mode of the acceleration sensor in the out-of-plane Z-axis direction according to the third embodiment of the present invention;

[0047] 13 is a schematic diagram of the out-of-plane parasitic modes in the Z-axis direction of the acceleration sensor according to the third embodiment of the present invention;

[0048] FIG14 is a schematic structural diagram of a coupling beam of an acceleration sensor according to a third embodiment of the present invention;

[0049] FIG15 is a schematic structural diagram of an X-axis single-degree-of-freedom spring of an acceleration sensor according to an embodiment of the present invention;

[0050] FIG16 is a schematic structural diagram of a Y-axis single-degree-of-freedom spring of an acceleration sensor according to an embodiment of the present invention;

[0051] FIG17 is a schematic structural diagram of an acceleration sensor according to a fourth embodiment of the present invention;

[0052] FIG18 is a schematic diagram of the detection mode of the acceleration sensor in the in-plane X-axis direction according to the fourth embodiment of the present invention;

[0053] FIG19 is a schematic diagram of the detection mode of the acceleration sensor in the Y-axis direction in the plane according to the fourth embodiment of the present invention;

[0054] FIG20 is a schematic diagram of the detection mode of the acceleration sensor in the out-of-plane Z-axis direction according to the fourth embodiment of the present invention;

[0055] FIG21 is a schematic diagram of the out-of-plane parasitic modes in the Z-axis direction of the acceleration sensor according to the fourth embodiment of the present invention;

[0056] FIG22 is a schematic structural diagram of a coupling beam of an acceleration sensor according to a fourth embodiment of the present invention;

[0057] FIG23 is a schematic structural diagram of a first embodiment of a first capacitor group of an acceleration sensor according to an embodiment of the present invention;

[0058] FIG24 is a schematic structural diagram of a second implementation of the first capacitor group of the acceleration sensor according to an embodiment of the present invention;

[0059] FIG25 is a schematic structural diagram of a first implementation of a second capacitor group of an acceleration sensor according to an embodiment of the present invention;

[0060] FIG26 is a schematic structural diagram of a second implementation of a second capacitor group of an acceleration sensor according to an embodiment of the present invention.

[0061] In the figure: 100, axis of symmetry; 200, first rotation axis; 300, second rotation axis; 11, first anchor point; 12, second anchor point; 2, first elastic member; 3, second elastic member; 31, X-axis single-degree-of-freedom spring; 32, Y-axis single-degree-of-freedom spring; 4, connecting arm; 41, accommodating groove; 5, first acceleration detection unit; 51, first seesaw unit; 511, first groove; 512, first sub-rotating part; 513, second sub-rotating part; 52, second seesaw unit; 521, second groove; 522, third sub-rotating part; 523, fourth Sub-rotating part; 53, out-of-plane displacement detection unit; 6, second acceleration detection unit; 611, first mass block; 612, first mounting groove; 613, first positive fixed electrode; 614, first negative fixed electrode; 615, first fixed electrode; 616, first movable electrode; 621, second mass block; 622, second mounting groove; 623, second positive fixed electrode; 624, second negative fixed electrode; 625, second fixed electrode; 626, second movable electrode; 71, first detection mass block; 72, second detection mass block; 8, coupling beam. DETAILED DESCRIPTION

[0062] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0063] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0064] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly refer to one or more of the features. Throughout the description of this application, unless otherwise specified, "plurality" means two or more. Furthermore, "and / or" in the specification and claims refers to at least one of the connected entities, and the character " / " generally indicates an "or" relationship between the connected entities.

[0065] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 therefore should not be understood as a limitation on the present application.

[0066] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances. Example 1

[0067] Referring to Figures 1 to 5 and Figures 23 and 25, an acceleration sensor is provided according to one aspect of the present invention. To facilitate description of the acceleration sensor of the present invention, a three-dimensional XYZ coordinate system is established, as shown in Figure 1, defining an in-plane X-axis direction, an in-plane Y-axis direction, and an out-plane Z-axis direction. The in-plane X-axis direction, the in-plane Y-axis direction, and the out-plane Z-axis direction are mutually perpendicular.

[0068] Specifically, the acceleration sensor includes a first acceleration detection unit 5, a second acceleration detection unit 6, a base, a connecting arm 4, a first anchor point 11, a first elastic member 2 and a second elastic member 3; the first acceleration detection unit 5 is used to detect the acceleration along the out-of-plane Z-axis direction; the first acceleration detection unit 5 includes a first seesaw unit 51 and a second seesaw unit 52, the first seesaw unit 51 and the second seesaw unit 52 are arranged opposite to each other, and the two are enclosed to form a ring structure; the second acceleration detection unit 6 is used to detect the acceleration along the in-plane X-axis direction and / or the in-plane Y-axis direction.

[0069] In one embodiment, the second acceleration detection unit 6 is configured to detect acceleration along the in-plane X-axis. In this case, the acceleration sensor is capable of simultaneously detecting acceleration along the in-plane X-axis and the out-of-plane Z-axis, thereby forming a dual-axis (in-plane X-axis and out-of-plane Z-axis) accelerometer.

[0070] In another embodiment, the second acceleration detection unit 6 is configured to detect acceleration along the in-plane Y-axis. In this case, the acceleration sensor can simultaneously detect acceleration along the in-plane Y-axis and acceleration along the out-of-plane Z-axis, thereby forming a dual-axis (in-plane Y-axis and out-of-plane Z-axis) accelerometer.

[0071] In other embodiments, the second acceleration detection unit 6 can simultaneously detect acceleration along the in-plane X-axis direction and the in-plane Y-axis direction. In this case, the acceleration sensor can simultaneously detect acceleration along the in-plane X-axis direction, the in-plane Y-axis direction, and the out-plane Z-axis direction, thereby forming a three-axis (in-plane X-axis, in-plane Y-axis, and out-plane Z-axis) accelerometer.

[0072] Further specifically, the annular structure surrounds the outside of the second acceleration detection unit 6; the first anchor point 11 is located in the middle of the base, and the connecting arm 4 is fixed to the base through the first anchor point 11; the connecting arm 4 is located between the first acceleration detection unit 5 and the second acceleration detection unit 6; the first acceleration detection unit 5 is connected to the connecting arm 4 through the first elastic member 2; the second acceleration detection unit 6 is connected to the connecting arm 4 through the second elastic member 3; the out-of-plane Z-axis direction, the in-plane X-axis direction, and the in-plane Y-axis direction are perpendicular to each other.

[0073] It should be noted that the first acceleration detection unit 5 is elastically connected to the connecting arm 4 to provide flexible support for the proof mass on the first acceleration detection unit 5 when it generates linear motion along the in-plane X-axis direction and / or the in-plane Y-axis direction, and to achieve co-coupling of the motion of the first acceleration detection unit 5 along the out-of-plane Z-axis direction. Simultaneously, the second acceleration detection unit 6 is elastically connected to the connecting arm 4 to provide flexible support for the proof mass on the second acceleration detection unit 6 when it generates linear motion along the in-plane X-axis direction and / or the in-plane Y-axis direction, and to achieve co-coupling of the motion of the first acceleration detection unit 5 along the out-of-plane Z-axis direction.

[0074] In the embodiment of the present application, the first anchor point 11 is arranged at the center of the structure of the acceleration sensor, and the first acceleration detection and the second acceleration detection share the first anchor point 11 through the connecting arm 4, so that the overall structure of the acceleration sensor is less affected by factors such as stress, thereby significantly improving the anti-interference ability of the acceleration sensor.

[0075] Exemplarily, the acceleration sensors are symmetrically distributed along their symmetry axis 100 ; and the first seesaw unit 51 and the second seesaw unit 52 are both symmetrically distributed along the symmetry axis 100 .

[0076] Optionally, the first acceleration detection unit 5 further includes an out-of-plane displacement detection unit 53;

[0077] The middle portion of the connecting arm 4 close to the second acceleration detection unit 6 is fixed to the first anchor point 11;

[0078] The first seesaw unit 51 is elastically connected to the first end of the connecting arm 4, and the second seesaw unit 52 is elastically connected to the second end of the connecting arm 4; the first seesaw unit 51 and the second seesaw unit 52 are symmetrically distributed along the symmetry axis 100 of the acceleration sensor; the first seesaw unit 51 forms two first seesaw structures on both sides of the symmetry axis 100, and the two first seesaw structures rotate along the first rotation axis 200; the second seesaw unit 52 forms two second seesaw structures on both sides of the symmetry axis 100, and the two second seesaw structures rotate along the second rotation axis 300; the first rotation axis 200 and the second rotation axis 300 are arranged in parallel, and the first rotation axis 200 and the second rotation axis 300 are both perpendicular to the symmetry axis 100;

[0079] The out-of-plane displacement detection unit 53 is provided on both the first seesaw unit 51 and the second seesaw unit 52 .

[0080] In the above-described embodiment, the first seesaw unit 51 and the second seesaw unit 52 are used as the out-of-plane acceleration detection structure, enabling the first seesaw unit 51 and the second seesaw unit 52 to rotate in opposite directions along the Y-axis under the influence of out-of-plane acceleration in the Z-axis direction. This allows the out-of-plane acceleration (i.e., Z-axis acceleration) of the acceleration sensor to be detected by the out-of-plane displacement detection unit 53 disposed on the first seesaw unit 51 and the second seesaw unit 52. Furthermore, when the two first seesaw structures or the two second seesaw structures are subjected to undesirable Y-axis angular acceleration, the two first seesaw structures or the two second seesaw structures rotate in the same direction. The capacitance changes of the out-of-plane displacement detection units 53 caused by this same rotation are offset during detection by the out-of-plane displacement detection units 53. Therefore, the layout of the two first seesaw structures and the two second seesaw structures significantly reduces the influence of Y-axis angular acceleration on the acceleration sensor, improves the cross-rejection ratio of the acceleration sensor, and enhances the accuracy of the acceleration sensor in detecting out-of-plane acceleration.

[0081] Optionally, a first groove 511 is provided on the outer side of the first seesaw unit 51, and a second groove 521 is provided on the inner side of the second seesaw unit 52, part of the first seesaw unit 51 is embedded in the second groove 521 and part of the second seesaw unit 52 is embedded in the first groove 511 to form a nested structure, and the nested structure is located between the first rotating shaft 200 and the second rotating shaft 300.

[0082] In the above embodiment, a nested structure is adopted between the first seesaw unit 51 and the second seesaw unit 52. The nested structure helps to extend the rotation arms of the first seesaw unit 51 and the second seesaw unit 52. At the same time, the out-of-plane displacement detection unit 53 can be arranged in an area farther from the rotation axis, thereby increasing the gain of the out-of-plane acceleration detection.

[0083] Optionally, the acceleration sensor further includes a first detection mass block 71 and a second detection mass block 72;

[0084] Each of the first seesaw structures includes a first sub-rotating portion 512 and a second sub-rotating portion 513, which are respectively located on opposite sides of the first rotating shaft 200, and a first groove 511 is provided on the outer side of the second sub-rotating portion 513. Each of the second seesaw structures includes a third sub-rotating portion 522 and a fourth sub-rotating portion 523, which are respectively located on opposite sides of the second rotating shaft 300, and a second groove 521 is provided on the inner side of the third sub-rotating portion 522.

[0085] The first detection mass block 71 is located on the first sub-rotation portion 512 , and the second detection mass block 72 is located on the fourth sub-rotation portion 523 . The first detection mass block 71 and the second detection mass block 72 are symmetrically arranged.

[0086] In the above embodiment, the first detection mass block 71 and the second detection mass block 72 form an asymmetric detection mass, and the asymmetric detection mass is located at the far end of the seesaw structure, so that the rotation of the first seesaw structure and the second seesaw structure caused by the out-of-plane acceleration is more sensitive, thereby improving the gain of the acceleration sensor detection.

[0087] Exemplarily, a first detection mass is set at the position where the two first sub-rotating parts 512 are connected, and a second detection mass is set at the position where the two fourth sub-rotating parts 523 are connected, which helps to further increase the distance between the detection mass and the rotation axis, thereby significantly improving the sensitivity of the rotation of the first seesaw structure and the second seesaw structure caused by out-of-plane acceleration, so as to further improve the gain of the acceleration sensor detection.

[0088] Optionally, the acceleration sensor further includes a coupling beam 8 , which extends in a direction perpendicular to the symmetry axis 100 , and one end of the coupling beam 8 is connected to the second sub-rotation portion 513 , and the other end is connected to the third sub-rotation portion 522 .

[0089] In the above embodiment, by setting a coupling beam 8 between the first seesaw unit 51 and the second seesaw unit 52, the coupling beam 8 can weaken the same-direction rotation of the first seesaw unit 51 and the second seesaw unit 52, further suppress the influence of the y-axis angular acceleration, and help to further improve the accuracy of the acceleration sensor in detecting external acceleration.

[0090] In one specific embodiment, out-of-plane displacement detection units 53 are provided on the first sub-rotating portion 512, the second sub-rotating portion 513, the third sub-rotating portion 522, and the fourth sub-rotating portion 523. Some of the out-of-plane displacement detection units 53 are located on the first seesaw unit 51 away from the first rotation axis 200, and some of the out-of-plane displacement detection units 53 are located on the second seesaw unit 52 away from the second rotation axis 300. The multiple out-of-plane displacement detection units 53 are symmetrically distributed along the symmetry axis 100.

[0091] For example, the coupling beam 8 is in a bar shape, and one end of the coupling beam 8 is fixed to the bottom wall of the first groove 511, and the other end is fixed to the bottom wall of the second groove 521. This makes the structure of the coupling beam 8 relatively simple, and facilitates the assembly of the acceleration sensor.

[0092] In some embodiments, the coupling beam 8 includes two parallel sub-beams. One end of each sub-beam is fixed to the bottom wall of the first groove 511, and the other end is fixed to the bottom wall of the second groove 521. This further improves the ability of the coupling beam 8 to reduce the co-directional rotation of the first seesaw unit 51 and the second seesaw unit 52, thereby better suppressing the influence of y-axis angular acceleration.

[0093] In other embodiments, the coupling beam 8 is in the shape of a rectangular ring. The middle portion of one side of the coupling beam 8 is fixed to the inner wall of the first groove 511, and the middle portion of the other side of the coupling beam 8 is fixed to the inner wall of the second groove 521. This makes the structural design of the coupling beam 8 more reasonable and effectively reduces the ability of the first seesaw unit 51 and the second seesaw unit 52 to rotate in the same direction.

[0094] Optionally, the two connecting arms 4 are symmetrically distributed along the symmetry axis 100 ; each connecting arm 4 is fixed to the base via one first anchor point 11 , and two first anchor points 11 are located between the two connecting arms 4 .

[0095] Optionally, referring to FIG1 and FIG23 , the second acceleration detection unit 6 is used to detect acceleration along the in-plane X-axis direction, and the second elastic member 3 is an X-axis single-degree-of-freedom spring 31 distributed along the in-plane Y-axis direction. The second acceleration detection unit 6 is fixed to the connecting arm 4 via the X-axis single-degree-of-freedom spring 31.

[0096] The second acceleration detection unit 6 includes a first mass block 611 and a first capacitor group; the first mass block 611 is provided with first mounting grooves 612 distributed along the in-plane Y-axis direction at intervals, and each first mounting groove 612 is provided with a first capacitor group;

[0097] The first capacitor group includes a first positive fixed electrode 613 and a first negative fixed electrode 614, which are distributed along the in-plane Y-axis direction; the side of the first positive fixed electrode 613 away from the first negative fixed electrode 614 forms a first differential detection capacitor with the first mass block 611, and the side of the first negative fixed electrode 614 away from the first positive fixed electrode 613 forms a second differential detection capacitor with the first mass block 611.

[0098] Referring to Figure 23, when the first mass block 611 is displaced to the left by the acceleration to the left along the X-axis, the capacitance spacing of the first differential detection capacitor decreases, and the capacitance spacing of the second differential detection capacitor increases. The capacitance difference between the first differential detection capacitor and the second differential detection capacitor changes in proportion to the acceleration to the left along the X-axis. By detecting the change in the capacitance difference, the real-time value of the acceleration to the left along the X-axis can be obtained.

[0099] Similarly, when the first mass 611 is displaced to the right by the acceleration along the X-axis, the real-time value of the acceleration to the right along the X-axis can also be obtained by detecting the change in the capacitance difference.

[0100] In the above embodiment, the second acceleration detection unit 6 has a reasonable structural design and can accurately measure the in-plane X-axis acceleration.

[0101] For example, referring to FIG. 15 , the X-axis single-degree-of-freedom spring 31 can be designed into different shapes according to the specific structure of the acceleration sensor to better enable the acceleration sensor to detect the in-plane X-axis acceleration.

[0102] In one embodiment, the out-of-plane displacement detection unit 53 includes a first out-of-plane detection plate and a second out-of-plane detection plate, which are opposite to each other and constitute a capacitor plate structure. The first out-of-plane detection plate is located on the base or the cavity cover, and the second out-of-plane detection plate is located on the first seesaw unit 51 and the second seesaw unit 52. Example 2

[0103] This embodiment provides another acceleration sensor, the structure of which is substantially the same as that of the embodiment 1, and only the different parts are described below.

[0104] 6 to 9 and 24 and 26 , the second acceleration detection unit 6 is used to detect acceleration along the in-plane X-axis direction.

[0105] 24 , the second acceleration detection unit 6 includes a first mass block 611 and a first capacitor group. First mounting slots 612 are symmetrically provided on the first mass block 611 , and a first capacitor group is provided in each of the first mounting slots 612 .

[0106] The first capacitor group includes a first fixed electrode 615 and a first movable electrode 616. The plurality of first fixed electrodes 615 and the plurality of first movable electrodes 616 are distributed along the in-plane Y-axis direction. The plurality of first movable electrodes 616 are spaced apart and connected to the first mass block 611. The plurality of first fixed electrodes 615 are spaced apart and fixed to the substrate via a second anchor point 12. A first movable electrode 616 is disposed between each of two connected first fixed electrodes 615. The first fixed electrode 615 and one first movable electrode 616 form a first differential detection capacitor, and the first fixed electrode 615 and the other first movable electrode 616 form a second differential detection capacitor.

[0107] When the first mass block 611 is displaced to the left by an acceleration to the left along the in-plane X-axis, the capacitance spacing of the first differential detection capacitor decreases, and the capacitance spacing of the second differential detection capacitor increases. The capacitance difference between the first differential detection capacitor and the second differential detection capacitor changes in proportion to the acceleration to the left along the in-plane X-axis. By detecting the change in the capacitance difference, the real-time value of the acceleration to the left along the in-plane X-axis can be obtained.

[0108] Similarly, when the first mass 611 is displaced rightward by the acceleration along the in-plane X-axis, the real-time value of the acceleration along the in-plane X-axis can be obtained by detecting the change in the capacitance difference.

[0109] Exemplarily, the first capacitor group includes multiple groups, and the first fixed electrode 615 of each first capacitor group is fixed to the substrate via a second anchor point 12. The multiple second anchor points 12 are all close to the first anchor point 11. Placing the anchor point of the fixed electrode for in-plane X-axis detection near the first anchor point 11 of the motion structure helps to ensure that all detection electrodes and the motion structure anchor point are located in the center of the structure, further improving the accelerometer's ability to resist interference from factors such as stress. Example 3

[0110] This embodiment provides another acceleration sensor, the structure of which is substantially the same as that of the embodiment 1, and only the different parts are described below.

[0111] Referring to Figures 10 to 14 and also to Figure 25 , the second acceleration detection unit 6 is used to detect acceleration along the in-plane Y-axis direction. The second elastic member 3 is a Y-axis single-degree-of-freedom spring 32 distributed along the in-plane X-axis direction. The second acceleration detection unit 6 is fixed to the connecting arm 4 via the Y-axis single-degree-of-freedom spring 32.

[0112] The second acceleration detection unit 6 includes a second mass block 621 and a second capacitor group; the middle portion of the second mass block 621 is provided with second mounting grooves 622 distributed along the in-plane X-axis direction, and each second mounting groove 622 is provided with a second capacitor group;

[0113] The second capacitor group includes a second positive fixed electrode 623 and a second negative fixed electrode 624, and the second positive fixed electrode 623 and the second negative fixed electrode 624 are distributed along the in-plane X-axis direction; the side of the second positive fixed electrode 623 away from the second negative fixed electrode 624 and the second mass block 621 form a third differential detection capacitor, and the side of the second negative fixed electrode 624 away from the second positive fixed electrode 623 and the second mass block 621 form a fourth differential detection capacitor.

[0114] Referring to Figure 25, when the second mass block 621 is displaced upward by the acceleration along the Y-axis, the capacitance spacing of the third differential detection capacitor decreases, and the capacitance spacing of the fourth differential detection capacitor increases. The capacitance difference between the third differential detection capacitor and the fourth differential detection capacitor changes in proportion to the acceleration along the Y-axis. By detecting the change in the capacitance difference, the real-time value of the acceleration along the Y-axis can be obtained.

[0115] Similarly, when the second mass 621 is displaced downward by the acceleration along the Y axis, the real-time value of the acceleration along the Y axis can also be obtained by detecting the change in the capacitance difference.

[0116] In the above embodiment, the second acceleration detection unit 6 has a reasonable structural design and can accurately measure the in-plane Y-axis acceleration.

[0117] For example, referring to FIG. 16 , the Y-axis single-degree-of-freedom spring 32 can be designed into different shapes according to the specific structure of the acceleration sensor to better enable the acceleration sensor to detect the in-plane Y-axis acceleration.

[0118] 26 , in another embodiment, the second acceleration detection unit 6 includes a second mass block 621 and a second capacitor group. Second mounting slots 622 are symmetrically provided on the second mass block 621 , and a second capacitor group is provided in each of the second mounting slots 622 .

[0119] The second capacitor group includes a second fixed electrode 625 and a second movable electrode 626. The plurality of second fixed electrodes 625 and the plurality of second movable electrodes 626 are distributed along the in-plane X-axis direction. The plurality of second movable electrodes 626 are spaced apart and connected to the second mass block 621. The plurality of second fixed electrodes 625 are spaced apart and fixed to the substrate via a second anchor point 12. A second movable electrode 626 is disposed between each of two connected second fixed electrodes 625. The second fixed electrode 625 and one second movable electrode 626 form a third differential detection capacitor, and the second fixed electrode 625 and another second movable electrode 626 form a fourth differential detection capacitor.

[0120] When the second mass block 621 is displaced upward by the acceleration along the Y-axis, the capacitance spacing of the third differential detection capacitor decreases, and the capacitance spacing of the fourth differential detection capacitor increases. The capacitance difference between the third differential detection capacitor and the fourth differential detection capacitor changes in proportion to the acceleration along the Y-axis. By detecting the change in the capacitance difference, the real-time value of the acceleration along the Y-axis can be obtained.

[0121] Similarly, when the second mass 621 is displaced downward by the acceleration along the Y axis, the real-time value of the acceleration along the Y axis can also be obtained by detecting the change in the capacitance difference.

[0122] Exemplarily, the second capacitor group includes multiple groups, and the second fixed electrode 625 of each second capacitor group is fixed to the substrate via a second anchor point 12. The multiple second anchor points 12 are all close to the first anchor point 11. Placing the anchor point of the fixed electrode for in-plane Y-axis detection near the first anchor point 11 of the motion structure helps to ensure that all detection electrodes and the motion structure anchor point are located in the center of the structure, further improving the accelerometer's ability to resist interference from factors such as stress. Example 4

[0123] This embodiment provides another acceleration sensor, the structure of which is substantially the same as that of the embodiment 1, and only the different parts are described below.

[0124] 17 to 22 , the annular structure surrounds the outer side of the connecting arm 4 ; a receiving groove 41 for mounting the second acceleration detection unit 6 is provided on the connecting arm 4 ; and the first anchor point 11 is located at the center of the connecting arm 4 .

[0125] In the above embodiment, the structural design of the connecting arm 4 is relatively reasonable, and it is also convenient to quickly install the second acceleration detection unit 6 in the accommodating groove 41, thereby helping to accurately detect the acceleration along the in-plane X-axis direction and / or the in-plane Y-axis direction.

[0126] Optionally, the two receiving grooves 41 are symmetrically arranged, which helps to accurately detect the acceleration along the in-plane X-axis direction and / or the in-plane Y-axis direction.

[0127] For example, the receiving groove 41 may be rectangular or polygonal.

[0128] Optionally, each of the accommodating grooves 41 is provided with a second acceleration detection unit 6;

[0129] One of the second acceleration detection units 6 is used to detect the acceleration in the X-axis direction within the plane; the other of the second acceleration detection units 6 is used to detect the acceleration in the Y-axis direction within the plane.

[0130] In the above embodiment, the acceleration sensor can simultaneously detect the acceleration along the in-plane X-axis direction, the acceleration along the in-plane Y-axis direction, and the acceleration along the out-of-plane Z-axis direction to form a three-axis accelerometer, which expands the detection range of the acceleration sensor and is very convenient to use.

[0131] In an embodiment of the present application, the detection masses of the three axes of the acceleration sensor share the same first anchor point 11, and the detection masses of the three axes are discretely distributed through a frame distributed between the in-plane X-axis, in-plane Y-axis and out-of-plane Z-axis detection masses, thereby avoiding cross-interference between the axes.

[0132] Exemplarily, the second acceleration detection unit 6 for detecting in-plane X-axis acceleration and the second acceleration detection unit 6 for detecting in-plane Y-axis acceleration are respectively located on opposite sides of the anchor point, thereby optimizing the structure of the acceleration sensor.

[0133] It should be noted that the detection mode in the in-plane X-axis direction refers to the acceleration sensor being affected by the acceleration in the in-plane X-axis direction, see Figures 2, 7 and 18; the detection mode in the in-plane Y-axis direction refers to the acceleration sensor being affected by the acceleration in the in-plane Y-axis direction, see Figures 11 and 19; the detection mode in the out-of-plane Z-axis direction refers to the acceleration sensor being affected by the acceleration in the out-of-plane Z-axis direction, see Figures 3, 8, 12 and 20; the parasitic mode in the out-of-plane Z-axis direction refers to the acceleration sensor being affected by both the out-of-plane Z-axis acceleration and the Y-axis angular acceleration, see Figures 4, 9, 13 and 21.

[0134] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An acceleration sensor, characterized in that, Comprising: A first acceleration detection unit for detecting acceleration in the out-of-plane Z-axis direction; The first acceleration detection unit includes a first seesaw unit and a second seesaw unit, the first seesaw unit and the second seesaw unit are arranged opposite to each other, and the two enclose a ring structure; A second acceleration detection unit for detecting acceleration in the in-plane X-axis direction and / or in-plane Y-axis direction; the ring structure surrounds the outside of the second acceleration detection unit; A substrate, a connecting arm, and a first anchor point, the first anchor point is located in the middle of the substrate, and the connecting arm is fixed to the substrate through the first anchor point; the connecting arm is located between the first acceleration detection unit and the second acceleration detection unit; A first elastic member and a second elastic member, the first acceleration detection unit is connected to the connecting arm through the first elastic member; the second acceleration detection unit is connected to the connecting arm through the second elastic member; The out-of-plane Z-axis direction, the in-plane X-axis direction, and the in-plane Y-axis direction are perpendicular to each other in pairs.

2. The acceleration sensor according to claim 1, characterized in that The first acceleration detection unit further includes an out-of-plane displacement detection unit; The middle of the side of the connecting arm close to the second acceleration detection unit is fixed to the first anchor point; The first seesaw unit is elastically connected to the first end of the connecting arm, and the second seesaw unit is elastically connected to the second end of the connecting arm; the first seesaw unit and the second seesaw unit are symmetrically distributed along the symmetry axis of the acceleration sensor respectively; the first seesaw unit forms two first seesaw structures on both sides of the symmetry axis respectively, and both first seesaw structures rotate along the first rotation axis; the second seesaw unit forms two second seesaw structures on both sides of the symmetry axis respectively, and both second seesaw structures rotate along the second rotation axis; the first rotation axis and the second rotation axis are arranged in parallel, and the first rotation axis and the second rotation axis are both perpendicular to the symmetry axis; The out-of-plane displacement detection unit is provided on both the first seesaw unit and the second seesaw unit.

3. The acceleration sensor according to claim 2, characterized in that, A first groove is provided on the outside of the first seesaw unit, and a second groove is provided on the inside of the second seesaw unit. Part of the first seesaw unit is embedded in the second groove and part of the second seesaw unit is embedded in the first groove to form a nested structure, and the nested structure is located between the first rotation axis and the second rotation axis.

4. The acceleration sensor according to claim 3, characterized in that, Further comprising a first detection mass block and a second detection mass block; Each of the first seesaw structures includes a first sub-rotating part and a second sub-rotating part, the first sub-rotating part and the second sub-rotating part are respectively located on opposite sides of the first rotation axis, and a first groove is provided on the outside of the second sub-rotating part; each of the second seesaw structures includes a third sub-rotating part and a fourth sub-rotating part, the third sub-rotating part and the fourth sub-rotating part are respectively located on opposite sides of the second rotation axis, and a second groove is provided on the inside of the third sub-rotating part; The first detection mass block is located on the first sub-rotating part, the second detection mass block is located on the fourth sub-rotating part, and the first detection mass block and the second detection mass block are symmetrically arranged.

5. The acceleration sensor according to claim 4, characterized in that, It further includes a coupling beam, the coupling beam extends in a direction perpendicular to the symmetry axis, and one end of the coupling beam is connected to the second sub-rotating part, and the other end is connected to the third sub-rotating part.

6. The acceleration sensor according to claim 1, wherein The second acceleration detection unit is used to detect the acceleration in the in-plane X-axis direction, the second elastic member is an X-axis single-degree-of-freedom spring distributed in the in-plane Y-axis direction, and the second acceleration detection unit is fixed to the connecting arm through the X-axis single-degree-of-freedom spring; The second acceleration detection unit includes a first mass block and a first capacitor group; first mounting grooves distributed in the in-plane Y-axis direction are arranged at intervals on the first mass block, and a first capacitor group is arranged in each of the first mounting grooves; The first capacitor group includes a first positive fixed electrode and a first negative fixed electrode, and the first positive fixed electrode and the first negative fixed electrode are distributed in the in-plane Y-axis direction; a first differential detection capacitor is formed between the first positive fixed electrode and the first mass block on the side away from the first negative fixed electrode, and a second differential detection capacitor is formed between the first negative fixed electrode and the first mass block on the side away from the first positive fixed electrode.

7. The acceleration sensor according to claim 1, wherein The second acceleration detection unit is used to detect the acceleration in the in-plane Y-axis direction, the second elastic member is a Y-axis single-degree-of-freedom spring distributed in the in-plane X-axis direction, and the second acceleration detection unit is fixed to the connecting arm through the Y-axis single-degree-of-freedom spring; The second acceleration detection unit includes a second mass block and a second capacitor group; second mounting grooves distributed in the in-plane X-axis direction are arranged at intervals in the middle of the second mass block, and a second capacitor group is arranged in each of the second mounting grooves; The second capacitor group includes a second positive fixed electrode and a second negative fixed electrode, and the second positive fixed electrode and the second negative fixed electrode are distributed in the in-plane X-axis direction; a third differential detection capacitor is formed between the second positive fixed electrode and the second mass block on the side away from the second negative fixed electrode, and a fourth differential detection capacitor is formed between the second negative fixed electrode and the second mass block on the side away from the second positive fixed electrode.

8. The acceleration sensor according to claim 1, wherein The annular structure surrounds the outside of the connecting arm; A receiving groove for installing the second acceleration detection unit is provided on the connecting arm; The first anchor point is located at the center of the connecting arm.

9. The acceleration sensor according to claim 8, wherein The two receiving grooves are symmetrically arranged.

10. The acceleration sensor according to claim 9, characterized in that, One second acceleration detection unit is arranged in each of the receiving grooves; One second acceleration detection unit is used to detect the acceleration in the in-plane X-axis direction; the other second acceleration detection unit is used to detect the acceleration in the in-plane Y-axis direction.

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