An accelerometer

Abstract

The application provides an accelerometer, which comprises a substrate, anchor points arranged on the substrate, and seesaw structures elastically connected with the anchor points, and further comprises a differential detection assembly for detecting acceleration of the seesaw structures, wherein the seesaw structures comprise first seesaw structures and second seesaw structures which are parallel to each other and oppositely arranged, the anchor points comprise first anchor points elastically connected with the first seesaw structures and second anchor points elastically connected with the second seesaw structures; the first seesaw structures comprise first elastic members connected with the first anchor points and first mass blocks connected with the first elastic members, the first mass blocks are driven by positive-phase carrier driving signals from the first anchor points; the second seesaw structures comprise second elastic members connected with the corresponding second anchor points and second mass blocks connected with the second elastic members, the second mass blocks are driven by negative-phase carrier driving signals from the second anchor points. The influence of the rotational angular acceleration noise can be effectively inhibited.

Description

[0001] The application relates to the technical field of micro-electro-mechanical systems, and in particular to an accelerometer.

[0002] In the related art, a multi-axis accelerometer uses an asymmetric rotating proof mass for Z-axis out-of-plane acceleration detection and Y-axis in-plane acceleration detection, and uses an entire seesaw structure as a linear proof mass for X-axis in-plane acceleration detection, and three axes are detected through corresponding capacitor plates.

[0003] However, the acceleration detection modes of the Y axis and the Z axis are the same as the motion modes subjected to external angular acceleration around the Z axis and the Y axis, and the mass center of the structure and the mass center of the proof mass are not at the same point, so that the accelerometer has poor resistance to external angular acceleration around the Z axis and the Y axis during detection. Meanwhile, when the substrate is subjected to stress such as heat and is deformed by tilting around the Y axis, the differential detection capacitor of the Z axis detection is directly affected by the tilting of the substrate, so that the output of the Z axis detection has a bias error caused by the tilting of the substrate.

[0004] The application aims to provide an accelerometer to inhibit the influence of the rotation angular acceleration on detection in the related art.

[0005] The application provides an accelerometer, which comprises a substrate, an anchor point arranged on the substrate, and a seesaw structure elastically connected to the anchor point, and further comprises a differential detection assembly for detecting the acceleration of the seesaw structure, wherein the seesaw structure comprises a first seesaw structure and a second seesaw structure arranged in parallel and reversely, the anchor point comprises a first anchor point elastically connected to the first seesaw structure and a second anchor point elastically connected to the second seesaw structure.

[0006] The first seesaw structure comprises a first elastic member connected to the first anchor point and a first mass block connected to the first elastic member, and the first mass block is driven by a positive-phase carrier driving signal from the first anchor point.

[0007] The second seesaw structure comprises a second elastic member connected to the corresponding second anchor point and a second mass block connected to the second elastic member, and the second mass block is driven by a negative-phase carrier driving signal from the second anchor point.

[0008] Further, the first mass block and the second mass block are asymmetric structures, wherein

[0009] The first mass block comprises a first mass portion connected to the first elastic member and a second mass portion connected to the first mass portion.​​​

[0010] The second mass block comprises a third mass portion connected with the second elastic member and a fourth mass portion connected with the third mass portion;

[0011] The moment of inertia of the first mass portion around the first elastic member matches the moment of inertia of the fourth mass portion around the second elastic member, and the moment of inertia of the second mass portion around the first elastic member matches the moment of inertia of the third mass portion around the second elastic member.

[0012] Further, the differential detection assembly comprises a first Z-axis capacitive detection electrode arranged on the substrate, which faces a side of the first mass block close to the first elastic member and a side of the second mass block away from the second elastic member to form a first Z-axis differential detection capacitor and a second Z-axis differential detection capacitor; wherein,

[0013] The product of the plate area of the first Z-axis differential detection capacitor and the distance from the plate to the first elastic member is equal to the product of the plate area of the second Z-axis differential detection capacitor and the distance from the plate to the second elastic member, and the plate spacing of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor is the same.

[0014] Further, the differential detection assembly further comprises a second Z-axis capacitive detection electrode arranged on the substrate, which faces a side of the first mass block away from the first elastic member and a side of the second mass block close to the second elastic member to form a third Z-axis differential detection capacitor and a fourth Z-axis differential detection capacitor; wherein,

[0015] The product of the plate area of the third Z-axis differential detection capacitor and the distance from the plate to the first elastic member is equal to the product of the plate area of the fourth Z-axis differential detection capacitor and the distance from the plate to the second elastic member, and the plate spacing of the third Z-axis differential detection capacitor and the fourth Z-axis differential detection capacitor is the same.

[0016] The product of the plate area of the third Z-axis differential detection capacitor and the distance from the plate to the first elastic member is equal to the product of the plate area of the first Z-axis differential detection capacitor and the distance from the plate to the first elastic member, and the plate spacing of the third Z-axis differential detection capacitor and the first Z-axis differential detection capacitor is the same, to form a double-differential Z-axis detection capacitor.

[0017] Further, the first mass block further comprises a first sidewall perpendicular to the Y axis; the second mass block further comprises a second sidewall perpendicular to the Y axis; the differential detection assembly comprises a first Y axis capacitive detection electrode disposed on the substrate, the first Y axis capacitive detection electrode facing the first sidewall and the second sidewall to form a first Y axis differential detection capacitor and a second Y axis differential detection capacitor; wherein,

[0018] The plate spacing of the first Y axis differential detection capacitor and the second Y axis differential detection capacitor is the same.

[0019] Further, the first mass block further comprises a third sidewall disposed opposite to the first sidewall; the second mass block further comprises a fourth sidewall disposed opposite to the second sidewall; the differential detection assembly further comprises a second Y axis capacitive detection electrode disposed on the substrate, the second Y axis capacitive detection electrode facing the third sidewall and the fourth sidewall to form a third Y axis differential detection capacitor and a fourth Y axis differential detection capacitor; wherein,

[0020] The plate spacing of the third Y axis differential detection capacitor and the fourth Y axis differential detection capacitor is the same; the facing area of the third Y axis differential detection capacitor and the first Y axis differential detection capacitor is equal, and the plate spacing is the same; the facing area of the fourth Y axis differential detection capacitor and the second Y axis differential detection capacitor is equal, and the plate spacing is the same, to form a double differential Y axis detection capacitor.

[0021] Further, the first mass block further comprises a fifth sidewall perpendicular to the X axis; the second mass block further comprises a sixth sidewall perpendicular to the X axis; the differential detection assembly comprises a first X axis capacitive detection electrode disposed on the substrate, the first X axis capacitive detection electrode facing the fifth sidewall and the sixth sidewall to form a first X axis differential detection capacitor and a second X axis differential detection capacitor; wherein,

[0022] The plate spacing of the first X axis differential detection capacitor and the second X axis differential detection capacitor is the same.

[0023] Further, the first mass block further comprises a seventh sidewall disposed opposite to the fifth sidewall; the second mass block further comprises an eighth sidewall disposed opposite to the sixth sidewall; the differential detection assembly further comprises a second X axis capacitive detection electrode disposed on the substrate, the second X axis capacitive detection electrode facing the seventh sidewall and the eighth sidewall to form a third X axis differential detection capacitor and a fourth X axis differential detection capacitor; wherein,

[0024] The plate spacing of the third X-axis differential detection capacitor and the fourth X-axis differential detection capacitor is the same, the facing area of the third X-axis differential detection capacitor and the first X-axis differential detection capacitor is equal, and the plate spacing is the same; the facing area of the fourth X-axis differential detection capacitor and the second X-axis differential detection capacitor is equal, and the plate spacing is the same, so as to form a double-differential X-axis detection capacitor.

[0025] Further, the first anchor points are at least two and oppositely arranged on the base; the first elastic members are at least two, one end of each first elastic member is connected with the first mass block, and the other end is connected with the corresponding first anchor point;

[0026] The second anchor points are at least two and oppositely arranged on the base; the second elastic members are at least two, one end of each second elastic member is connected with the second mass block, and the other end is connected with the corresponding second anchor point.

[0027] Further, it further comprises an upper cover arranged on the side of the seesaw structure away from the base.

[0028] Further, the first seesaw structure and the second seesaw structure are in a nested distribution.

[0029] The beneficial effects of the present application are that the positive phase carrier driving signal and the reverse phase carrier driving signal with opposite phases are respectively applied to the first anchor points of the first seesaw structure and the second anchor points of the second seesaw structure which are parallel and opposite, the electric potentials of the first seesaw structure and the second seesaw structure are respectively unified with the electric potentials at the first anchor points and the second anchor points, and differential driving is formed. The detection mode of the two parallel and opposite seesaw structures driven by two carrier signals makes the common mode change of the differential detection assembly caused by the inclination of the base around the rotation shafts where the first elastic members and the second elastic members are located due to the influence of external factors such as stress, which is offset by each other, and can effectively suppress the influence of rotation angle acceleration noise. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The anchor point and the seesaw structure are provided with a three-dimensional schematic view of the embodiment of the present application;

[0031] Figure 2 The anchor point and the seesaw structure are provided with a planar schematic view of the embodiment of the present application;

[0032] Figure 3 The first seesaw structure mode in the X-axis acceleration detection mode is provided for the embodiment of the present application;

[0033] Figure 4 The second seesaw structure mode in the X-axis acceleration detection mode is provided for the embodiment of the present application;

[0034] Figure 5 This is the first seesaw structure mode in the Y-axis acceleration detection mode provided in the embodiments of the present invention;

[0035] Figure 6 This refers to the second seesaw structure mode in the Y-axis acceleration detection mode provided in this embodiment of the invention;

[0036] Figure 7 This is the first seesaw structure mode in the Z-axis acceleration detection mode provided in the embodiments of the present invention;

[0037] Figure 8 This is the second seesaw structure mode in the Z-axis acceleration detection mode provided in the embodiment of the present invention.

Detailed Implementation Methods

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] Please see Figure 1 and Figure 2 This invention provides an accelerometer, including a base, an anchor point 1 disposed on the base, and a seesaw structure 2 elastically connected to the anchor point 1. The accelerometer also includes a differential detection component 3 for detecting the acceleration of the seesaw structure 2. The seesaw structure 2 includes a first seesaw structure 21 and a second seesaw structure 22 placed parallel to each other and in opposite directions. The anchor point 1 includes a first anchor point 11 elastically connected to the first seesaw structure 21 and a second anchor point 12 elastically connected to the second seesaw structure 22. The first seesaw structure 21 includes a first elastic element 211 connected to the first anchor point 11 and a first mass block 212 connected to the first elastic element 211. The first mass block 212 is driven from the first anchor point 11 by a positive phase carrier drive signal. The second seesaw structure 22 includes a second elastic element 221 connected to the corresponding second anchor point 12 and a second mass block 222 connected to the second elastic element 221. The second mass block 222 is driven from the second anchor point 12 by an inverse phase carrier drive signal.

[0040] In this embodiment, the plane containing the base is the base plane, and anchor point 1 is fixed to the base plane; as shown Figure 7 and Figure 8 The Z-axis acceleration detection mode shown in the diagram, under the action of acceleration in the Z-axis direction, the first mass block 212 of the first seesaw structure 21 rotates counterclockwise and tilts around the first axis 4 (i.e., the axis formed by the first elastic element 211 and the first anchor point 11), and the second mass block 222 of the second seesaw structure 22 rotates clockwise and tilts around the second axis 5 (i.e., the axis formed by the first elastic element 211 and the first anchor point 11). The first axis 4 and the second axis 5 are in the same direction as the Y-axis; as shown in the diagram. Figure 5 and Figure 6As shown in the Y-axis acceleration detection mode, under the action of Y-axis acceleration, the first seesaw structure 21 rotates and tilts clockwise around the Z-axis, and the second seesaw structure 22 rotates and tilts counterclockwise around the Z-axis; as shown in the Y-axis acceleration detection mode, Figure 3 and Figure 4 As shown in the X-axis acceleration detection mode, under the action of X-axis acceleration, the first seesaw structure 21 and the second seesaw structure 22 both translate along the X-axis. By adjusting the parameters of the first elastic member 211 and the second elastic member 221, the corresponding modal frequencies of the first seesaw structure 21 and the second seesaw structure 22 are close or even consistent. The first seesaw structure 21 and the second seesaw structure 22 are independent of each other, and the in-phase carrier driving signal and the anti-phase carrier driving signal with opposite phases are respectively applied to the first anchor point 11 of the first seesaw structure 21 and the second anchor point 12 of the second seesaw structure 22 which are parallel and opposite. The potentials of the first seesaw structure 21 and the second seesaw structure 22 are unified with the potentials at the first anchor point 11 and the second anchor point 12, respectively, to form differential driving. This detection method of differentially driving two parallel and opposite seesaw structures 2 by two carrier waves makes the common-mode change of the differential detection assembly 3 caused by the inclination of the substrate around the rotation shaft of the first elastic member 211 and the second elastic member 221 under the influence of external factors such as stress be mutually canceled out, thereby effectively suppressing the influence of rotational angular acceleration noise.

[0041] Further, the first mass block 212 and the second mass block 222 are asymmetric structures; wherein the first mass block 212 includes a first mass portion 2121 connected with the first elastic member 211 and a second mass portion 2122 connected with the first mass portion 2121, and the first mass portion 2121 and the second mass portion 2122 are asymmetric structures with the first rotation shaft 4 as the axis; the second mass block 222 includes a third mass portion 2221 connected with the second elastic member 221 and a fourth mass portion 2222 connected with the third mass portion 2221, and the third mass portion 2221 and the fourth mass portion 2222 are asymmetric structures with the second rotation shaft 5 as the axis; of course, the first mass block 212 and the second mass block 222 can also be asymmetric structures with the first rotation shaft 4 or the second rotation shaft 5 as the axis. Wherein, the moment of inertia of the first mass portion 2121 around the first elastic member 211 matches the moment of inertia of the fourth mass portion 2222 around the second elastic member 221, and the moment of inertia of the second mass portion 2122 around the first elastic member 211 matches the moment of inertia of the third mass portion 2221 around the second elastic member 221.

[0042] In this embodiment, the mass distribution of the first mass block 212 on both sides of the first elastic member 211 is asymmetric, wherein the inertia inspection mass block is the asymmetric part of the mass distribution of the first mass block 212 (i.e., the asymmetric part with the first rotation axis 4 as the axis), one side of the first elastic member 211 where the first mass block 212 is located is the first mass part 2121, and the other side of the first elastic member 211 is the second mass part 2122; the mass distribution of the second mass block 222 on both sides of the second elastic member 221 is asymmetric, wherein the inertia inspection mass block is the asymmetric part of the mass distribution of the second mass block 222 (i.e., the asymmetric part with the second rotation axis 5 as the axis), one side of the second elastic member 221 where the second mass block 222 is located is the third mass part 2221, and the other side of the second elastic member 221 is the fourth mass part 2222.

[0043] It should be noted that in some embodiments, the first seesaw structure 21 and the second seesaw structure 22 can also be in a nested distribution. At this time, the second mass part 2122 has a first matching opening 2123 in the middle, and the shape matches the shape of the third mass part 2221, and the first mass part 2121 has a second matching opening 2124 in the middle, and the shape of the second matching opening 2124 matches the shape of the fourth mass part 2222. Among them, the second matching opening 2124 and the first matching opening 2123 are in communication, and the cross-sectional area of the first matching opening 2123 is greater than that of the second matching opening 2124.

[0044] Specifically, the differential detection assembly 3 includes a first Z-axis capacitive detection electrode 31 arranged on the substrate, the first Z-axis capacitive detection electrode 31 is opposite to the side of the first mass block 212 close to the first elastic member 211 and the side of the second mass block 222 away from the second elastic member 221, to form a first Z-axis differential detection capacitor and a second Z-axis differential detection capacitor; wherein the product of the plate area of the first Z-axis differential detection capacitor and the distance from the first elastic member 211 is equal to the product of the plate area of the second Z-axis differential detection capacitor and the distance from the second elastic member 221, and the plate spacing of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor is the same.

[0045] The facing areas of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor in the embodiment are approximately equal, and the plate spacing is approximately the same. The facing areas can be equal or not equal. The Z-axis out-of-plane acceleration acting on the seesaw structure 2 causes the first seesaw structure 21 to rotate and tilt in the opposite direction around the rotation axis of the first elastic member 211 and the second seesaw structure 22 to rotate and tilt in the opposite direction around the second elastic member 221. The capacitance spacing of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor changes differentially. The differential mode change of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor caused by the tilt of the first seesaw structure 21 and the second seesaw structure 22 can be detected by the capacitance detection circuit connected to the first Z-axis capacitance detection electrode 31, so as to calculate the Z-axis acceleration.

[0046] When the first seesaw structure 21 and the second seesaw structure 22 are affected by the rotation angle acceleration noise of the external environment around the first elastic member 211 and the second elastic member 221 respectively, when the first seesaw structure 21 and the second seesaw structure 22 are tilted in the same direction around the rotation axis of the first elastic member 211 and the second elastic member 221 respectively, the common mode change of the differential detection first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor caused by the tilt is mutually canceled, so as to weaken the influence of the rotation angle acceleration noise of the external environment around the first elastic member 211 and the second elastic member 221 on the accelerometer.

[0047] When the substrate is tilted around the rotation axis of the first elastic member 211 and the second elastic member 221 due to the influence of external factors such as stress, the common mode change of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor caused by the tilt is mutually canceled, so as to weaken the influence of the rotation angle acceleration noise of the external environment around the first elastic member 211 and the second elastic member 221 on the accelerometer.

[0048] Further, the differential detection assembly 3 further comprises a second Z-axis capacitive detection electrode 32 arranged on the substrate, the second Z-axis capacitive detection electrode 32 facing the side of the first mass 212 away from the first elastic member 211 and the side of the second mass 222 close to the second elastic member 221 to form a third Z-axis differential detection capacitor and a fourth Z-axis differential detection capacitor; wherein the product of the plate area of the third Z-axis differential detection capacitor and the distance from the plate to the first elastic member 211 is equal to the product of the plate area of the fourth Z-axis differential detection capacitor and the distance from the plate to the second elastic member 221, and the plate spacing of the third Z-axis differential detection capacitor and the fourth Z-axis differential detection capacitor is the same; the product of the plate area of the third Z-axis differential detection capacitor and the distance from the plate to the first elastic member 211 is equal to the product of the plate area of the first Z-axis differential detection capacitor and the distance from the plate to the first elastic member 211, and the plate spacing of the third Z-axis differential detection capacitor and the first Z-axis differential detection capacitor is the same to form a double differential Z-axis detection capacitor.

[0049] In the embodiment, the facing area of the third Z-axis differential detection capacitor and the fourth Z-axis differential detection capacitor is approximately equal to the facing area of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor, the plate spacing of the third Z-axis differential detection capacitor and the fourth Z-axis differential detection capacitor is approximately the same as the plate spacing of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor, and constitutes a double differential detection capacitor, and the anti-interference ability and the acceleration detection sensitivity of the accelerometer can be further enhanced by differential detection. It should be noted that the product of the plate area of the fourth Z-axis differential detection capacitor and the distance from the plate to the second elastic member 221 is equal to the product of the plate area of the second Z-axis differential detection capacitor and the distance from the plate to the second elastic member 221, and the plate spacing of the fourth Z-axis differential detection capacitor and the second Z-axis differential detection capacitor is the same.

[0050] Specifically, the first mass 212 further comprises a first side wall 2123 perpendicular to the Y-axis; the second mass 222 further comprises a second side wall 2223 perpendicular to the Y-axis; the differential detection assembly 3 comprises a first Y-axis capacitive detection electrode 33 arranged on the substrate, the first Y-axis capacitive detection electrode 33 facing the first side wall 2123 and the second side wall 2223 to form a first Y-axis differential detection capacitor and a second Y-axis differential detection capacitor; wherein the plate spacing of the first Y-axis differential detection capacitor and the second Y-axis differential detection capacitor is the same.

[0051] In the embodiment, the first Y-axis capacitive detection electrode 33 is arranged on the substrate and is perpendicular to the substrate plane, and the first Y-axis capacitive detection electrode 33 is perpendicular to the Y-axis. The opposite areas of the first Y-axis differential detection capacitor and the second Y-axis differential detection capacitor are approximately equal, and the spacings are approximately the same. The Y-axis acceleration acting on the seesaw structure 2 causes the first seesaw structure 21 and the second seesaw structure 22 to rotate and tilt in opposite directions around the Z-axis, and the capacitive spacings of the first Y-axis differential detection capacitor and the second Y-axis differential detection capacitor differentially change. The differential mode change of the first Y-axis differential detection capacitor and the second Y-axis differential detection capacitor caused by the tilt of the seesaw can be detected by the capacitive detection circuit connected to the first Y-axis capacitive detection electrode 33, so as to calculate the Y-axis acceleration.

[0052] When the first seesaw structure 21 and the second seesaw structure 22 are affected by external rotational angular acceleration noise around the Z-axis, the first seesaw structure 21 and the second seesaw structure 22 rotate and tilt in the same direction around the Z-axis, and the common mode change of the differential detection capacitors caused by the tilt is mutually canceled, so as to weaken the influence of the external rotational angular acceleration noise around the central rotation axis on the accelerometer.

[0053] Further, the first mass block 212 further comprises a third side wall 2124 arranged opposite to the first side wall 2123; the second mass block 222 further comprises a fourth side wall 2224 arranged opposite to the second side wall 2223; and the differential detection assembly 3 further comprises a second Y-axis capacitive detection electrode 34 arranged on the substrate, the second Y-axis capacitive detection electrode 34 opposite to the third side wall 2124 and the fourth side wall 2224 to form a third Y-axis differential detection capacitor and a fourth Y-axis differential detection capacitor; wherein the plate spacings of the third Y-axis differential detection capacitor and the fourth Y-axis differential detection capacitor are the same; the opposite areas of the third Y-axis differential detection capacitor and the first Y-axis differential detection capacitor are equal, and the plate spacings are the same; and the opposite areas of the fourth Y-axis differential detection capacitor and the second Y-axis differential detection capacitor are equal, and the plate spacings are the same, so as to form a double differential Y-axis detection capacitor.

[0054] In the embodiment, the opposite areas of the third Y-axis differential detection capacitor and the fourth Y-axis differential detection capacitor are approximately equal to the opposite areas of the first Y-axis differential detection capacitor and the second Y-axis differential detection capacitor, and the plate spacings of the third Y-axis differential detection capacitor and the fourth Y-axis differential detection capacitor are approximately the same as the plate spacings of the first Y-axis differential detection capacitor and the second Y-axis differential detection capacitor, and the third Y-axis differential detection capacitor and the fourth Y-axis differential detection capacitor constitute a double differential detection capacitor. The differential detection can further enhance the anti-interference ability and the acceleration detection sensitivity of the accelerometer.

[0055] Specifically, the first mass 212 further comprises a fifth side wall 2125 perpendicular to the X axis; the second mass 222 further comprises a sixth side wall 2225 perpendicular to the X axis; the differential detection assembly 3 comprises a first X axis capacitive detection electrode 35 arranged on the substrate, the first X axis capacitive detection electrode 35 facing the fifth side wall 2125 and the sixth side wall 2225 to form a first X axis differential detection capacitor and a second X axis differential detection capacitor; wherein the plate spacing of the first X axis differential detection capacitor and the second X axis differential detection capacitor is the same.

[0056] In the embodiment, the first X axis capacitive detection electrode 35 perpendicular to the substrate plane is arranged on the substrate, and the first X axis capacitive detection electrode 35 is perpendicular to the X axis. The facing areas of the first X axis differential detection capacitor and the second X axis differential detection capacitor are approximately equal, and the spacings are approximately the same. The X axis acceleration acting on the seesaw structure 2 causes the first seesaw structure 21 and the second seesaw structure 22 to translate along the X axis around the Z axis, and the capacitive spacings of the first X axis differential detection capacitor and the second X axis differential detection capacitor differentially change. The differential mode change of the first X axis differential detection capacitor and the second X axis differential detection capacitor caused by the inclination of the seesaw can be detected through the capacitive detection circuit connected to the first X axis capacitive detection electrode 35, so as to calculate the size of the X axis acceleration.

[0057] Further, the first mass 212 further comprises a seventh side wall 2126 arranged opposite to the fifth side wall 2125; the second mass 222 further comprises an eighth side wall 2226 arranged opposite to the sixth side wall 2225; the differential detection assembly 3 further comprises a second X axis capacitive detection electrode 36 arranged on the substrate, the second X axis capacitive detection electrode 36 facing the seventh side wall 2126 and the eighth side wall 2226 to form a third X axis differential detection capacitor and a fourth X axis differential detection capacitor; wherein the plate spacings of the third X axis differential detection capacitor and the fourth X axis differential detection capacitor are the same, the facing areas of the third X axis differential detection capacitor and the first X axis differential detection capacitor are equal, and the plate spacings are the same, the facing areas of the fourth X axis differential detection capacitor and the second X axis differential detection capacitor are equal, and the plate spacings are the same, to form a double differential X axis detection capacitor.

[0058] In the embodiment, the facing areas of the third X axis differential detection capacitor and the fourth X axis differential detection capacitor are approximately equal to the facing areas of the first X axis differential detection capacitor and the second X axis differential detection capacitor, and the plate spacings of the third X axis differential detection capacitor and the fourth X axis differential detection capacitor are approximately the same as the plate spacings of the first X axis differential detection capacitor and the second X axis differential detection capacitor, and constitute a double differential detection capacitor. Through differential detection, the anti-interference ability and the acceleration detection sensitivity of the accelerometer can be further enhanced

[0059] It should be noted that each axis acceleration detection can be realized by connecting a single detection electrode to a capacitance detection circuit; further, a differential electrode arrangement is adopted to further enhance the robustness and detection sensitivity of the accelerometer.

[0060] Further, the first anchor points 11 are at least two and are oppositely arranged on the base; the first elastic members 211 are at least two, one end of each first elastic member 211 is connected with the first mass block 212, and the other end is connected with the corresponding first anchor point 11; the second anchor points 12 are at least two and are oppositely arranged on the base; the second elastic members 221 are at least two, one end of each second elastic member 221 is connected with the second mass block 222, and the other end is connected with the corresponding second anchor point 12.

[0061] In the embodiment, the two first anchor points 11 are oppositely arranged on the two sides of the third mass part 2221 and are fixed on the base respectively. To match this, the first elastic member 211 is arranged on the corresponding first anchor point 11 and is connected with the first mass block 212 to realize the movement of the first seesaw. Of course, the two second anchor points 12 are also oppositely arranged on the two sides of the third mass part 2221 and are fixed on the base respectively. Further, the second anchor points 12 and the first anchor points 11 on the same side are arranged at intervals, and to match this, the second elastic member 221 is arranged on the corresponding second anchor point 12 and is connected with the third mass part 2221 to realize the movement of the second seesaw. It should be noted that the number of the first anchor points 11 and the second anchor points 12 can also be single or multiple, which is not particularly limited here, as long as the first seesaw structure 21 can be flexibly fixed on the first anchor points 11 through the first elastic member 211, the second seesaw structure 22 can be flexibly fixed on the second anchor points 12 through the second elastic member 221, and of course, the number of the first elastic member 211 and the second elastic member 221 is also arranged correspondingly. In the embodiment, the first elastic member 211 and the second elastic member 221 are preferably springs, and of course, in some other embodiments, the first elastic member 211 and the second elastic member 221 can also be other types of elastic members.

[0062] Further, the upper cover arranged on the side of the seesaw structure 2 away from the base is also included.

[0063] In the embodiment, the plane where the upper cover is located is the upper cover plane, and the upper cover plane and the base plane are respectively above and below the plane where the seesaw structure 2 is located. In some embodiments, the first Z-axis capacitance detection electrode 31, the second Z-axis capacitance detection electrode 32, the second Y-axis capacitance detection electrode 34 and / or the second X-axis capacitance detection electrode 36 can also be arranged on the upper cover plane.

[0064] The above merely describes the embodiments of the present application, and it should be pointed out that, for those skilled in the art, improvements can be made without departing from the inventive concept, and these all belong to the protection scope of the present application.

Claims

1. An accelerometer, comprising a base, an anchor point disposed on the base, and a seesaw structure elastically connected to the anchor point, characterized in that, The accelerometer further includes a differential detection component for detecting the acceleration of the seesaw structure. The differential detection component has a dual differential Z-axis detection capacitor, a dual differential Y-axis detection capacitor, and a dual differential X-axis detection capacitor formed on the substrate to complete the acceleration detection of the Z-axis, Y-axis, and X-axis. The seesaw structure includes a first seesaw structure and a second seesaw structure placed parallel to each other and in opposite directions. Both the first seesaw structure and the second seesaw structure can rotate about the Z-axis and a rotation axis coaxial with the Y-axis, and both the first seesaw structure and the second seesaw structure can translate along the X-axis. The anchor point includes a first anchor point elastically connected to the first seesaw structure and a second anchor point elastically connected to the second seesaw structure. The first seesaw structure includes a first elastic element connected to the first anchor point and a first mass block connected to the first elastic element. The first mass block is driven from the first anchor point by a positive phase carrier drive signal. The second seesaw structure includes a second elastic element connected to the corresponding second anchor point and a second mass block connected to the second elastic element. The second mass block is driven from the second anchor point by an inverted carrier drive signal.

2. The accelerometer according to claim 1, characterized in that: The first mass block and the second mass block have an asymmetric structure; wherein... The first mass block includes a first mass portion connected to the first elastic member and a second mass portion connected to the first mass portion; The second mass block includes a third mass portion connected to the second elastic member and a fourth mass portion connected to the third mass portion; The moment of inertia of the first mass portion about the first elastic element is matched with the moment of inertia of the fourth mass portion about the second elastic element, and the moment of inertia of the second mass portion about the first elastic element is matched with the moment of inertia of the third mass portion about the second elastic element.

3. The accelerometer according to claim 1, characterized in that: The differential detection assembly includes a first Z-axis capacitance detection electrode disposed on the substrate. The first Z-axis capacitance detection electrode faces the side of the first mass block near the first elastic member and the side of the second mass block away from the second elastic member, thereby forming a first Z-axis differential detection capacitor and a second Z-axis differential detection capacitor; wherein... The product of the plate area of ​​the first Z-axis differential detection capacitor and the distance from the plate to the first elastic element is equal to the product of the plate area of ​​the second Z-axis differential detection capacitor and the distance from the plate to the second elastic element, and the plate spacing of the first Z-axis differential detection capacitor and the second Z-axis differential detection capacitor is the same.

4. The accelerometer according to claim 3, characterized in that: The differential detection assembly further includes a second Z-axis capacitance detection electrode disposed on the substrate. The second Z-axis capacitance detection electrode faces the side of the first mass block away from the first elastic member and the side of the second mass block close to the second elastic member, thereby forming a third Z-axis differential detection capacitor and a fourth Z-axis differential detection capacitor; wherein... The product of the plate area of ​​the third Z-axis differential detection capacitor and the distance from the plate to the first elastic element is equal to the product of the plate area of ​​the fourth Z-axis differential detection capacitor and the distance from the plate to the second elastic element, and the plate spacing of the third Z-axis differential detection capacitor and the fourth Z-axis differential detection capacitor is the same. The product of the plate area of ​​the third Z-axis differential detection capacitor and the distance from the plate to the first elastic element is equal to the product of the plate area of ​​the first Z-axis differential detection capacitor and the distance from the plate to the first elastic element. The plate spacing of the third Z-axis differential detection capacitor is the same as that of the first Z-axis differential detection capacitor, so as to form a dual differential Z-axis detection capacitor.

5. The accelerometer according to claim 2, characterized in that: The first mass block further includes a first sidewall perpendicular to the Y-axis; the second mass block further includes a second sidewall perpendicular to the Y-axis; the differential detection assembly includes a first Y-axis capacitance detection electrode disposed on the substrate, the first Y-axis capacitance detection electrode being directly opposite the first sidewall and the second sidewall to form a first Y-axis differential detection capacitor and a second Y-axis differential detection capacitor; wherein... The plate spacing of the first Y-axis differential detection capacitor and the second Y-axis differential detection capacitor is the same.

6. The accelerometer according to claim 5, characterized in that: The first mass block further includes a third sidewall disposed opposite to the first sidewall; the second mass block further includes a fourth sidewall disposed opposite to the second sidewall; the differential detection assembly further includes a second Y-axis capacitance detection electrode disposed on the substrate, the second Y-axis capacitance detection electrode being directly opposite the third sidewall and the fourth sidewall to form a third Y-axis differential detection capacitor and a fourth Y-axis differential detection capacitor; wherein... The third Y-axis differential detection capacitor and the fourth Y-axis differential detection capacitor have the same plate spacing; the third Y-axis differential detection capacitor and the first Y-axis differential detection capacitor have the same facing area and the same plate spacing, and the fourth Y-axis differential detection capacitor and the second Y-axis differential detection capacitor have the same facing area and the same plate spacing, so as to form a dual differential Y-axis detection capacitor.

7. The accelerometer according to claim 2, characterized in that: The first mass block further includes a fifth sidewall perpendicular to the X-axis; the second mass block further includes a sixth sidewall perpendicular to the X-axis; the differential detection assembly includes a first X-axis capacitance detection electrode disposed on the substrate, the first X-axis capacitance detection electrode being directly opposite the fifth and sixth sidewalls to form a first X-axis differential detection capacitor and a second X-axis differential detection capacitor; wherein, The plate spacing of the first X-axis differential detection capacitor and the second X-axis differential detection capacitor is the same.

8. The accelerometer according to claim 7, characterized in that: The first mass block further includes a seventh sidewall disposed opposite to the fifth sidewall; the second mass block further includes an eighth sidewall disposed opposite to the sixth sidewall; the differential detection assembly further includes a second X-axis capacitance detection electrode disposed on the substrate, the second X-axis capacitance detection electrode being directly opposite the seventh and eighth sidewalls to form a third X-axis differential detection capacitor and a fourth X-axis differential detection capacitor; wherein... The third X-axis differential detection capacitor and the fourth X-axis differential detection capacitor have the same plate spacing. The third X-axis differential detection capacitor and the first X-axis differential detection capacitor have the same facing area and the same plate spacing. The fourth X-axis differential detection capacitor and the second X-axis differential detection capacitor have the same facing area and the same plate spacing, so as to form a dual differential X-axis detection capacitor.

9. The accelerometer according to any one of claims 1-8, characterized in that: There are at least two first anchor points, which are disposed opposite to each other on the base; there are at least two first elastic elements, one end of each first elastic element is connected to the first mass block, and the other end is connected to the corresponding first anchor point; There are at least two second anchor points, which are disposed opposite to each other on the base; there are at least two second elastic elements, one end of each second elastic element is connected to the second mass block, and the other end is connected to the corresponding second anchor point.

10. The accelerometer according to claim 1, characterized in that: It also includes a top cover disposed on the side of the seesaw structure opposite to the base.

11. The accelerometer according to claim 1, characterized in that: The first seesaw structure and the second seesaw structure are nested together.

Images