CN105044387B - A kind of inertia measurement device and inertial measurement system - Google Patents

Abstract

The invention discloses an inertial measurement device and an inertial measurement system. The mass block (1) of the former is connected to the anchoring part (3) through two elastic torsion beams (4) extending along the X axis, and the mass block (1) ) on both sides of the X-axis have unequal masses; the substrate of the former is provided with a fixed electrode group, and the fixed electrode group has four fixed electrodes (2) to form the first to fourth Detection capacitors, wherein, the first and second detection capacitors, and the third and fourth detection capacitors all constitute differential capacitances for X-axis inertial signal detection, and the first and fourth detection capacitors, and the second and third detection capacitors are both Constitutes the differential capacitance for the Y-axis inertial signal detection. The device of the present invention can realize the detection of X-axis and Y-axis inertial signals by sharing the fixed electrode group, so it can improve the sensitivity under the same chip area and save the chip area under the same sensitivity.

Description

An inertial measurement device and an inertial measurement system

technical field

The invention belongs to the field of micro-electromechanical (MEMS), more precisely, the invention relates to an inertial measurement device of a micro-electromechanical device and an inertial measurement system using the inertial measurement device.

Background technique

At present, the inertial measurement system generally uses the principle of differential capacitance to detect the inertial signal, specifically, the inertial signal in the X-axis direction is detected through the differential capacitance formed by the fixed electrode pair of the inertial measurement device opposite in the X-axis direction, and the inertial signal is detected through the inertial measurement device. The differential capacitance formed by the pair of fixed electrodes facing each other in the Y-axis direction of the measuring device detects the inertial signal in the Y-axis direction. The inertial measurement system using this inertial signal detection method needs to set up independent fixed electrode pairs in the X-axis and Y-axis directions of the inertial measurement device. The upper consumption is relatively large, which is not conducive to the control of chip size.

Contents of the invention

An object of the present invention is to provide a new technical solution of an inertial measurement device and a corresponding inertial measurement system.

According to a first aspect of the present invention, there is provided an inertial measurement device, which includes a substrate, a mass block located above the substrate, and an anchor portion fixed on the substrate, the anchor portion is located on the mass The structural center of the block, the mass block is connected to the anchor part by two elastic torsion beams extending along the X axis, and the two elastic torsion beams are symmetrical about the Y axis, wherein the X axis and the The Y axes are perpendicular to each other on the plane where the mass block is located, and both pass through the center of the structure; the mass of the mass block on both sides of the Y axis is equal, and the mass of the parts on both sides of the X axis is not equal ;

The inertial measurement device also includes at least one fixed electrode group arranged on the substrate, the fixed electrode group has four fixed electrodes, and the mass acts as the movable electrode and the four fixed electrodes of the fixed electrode group. The electrodes respectively form a first detection capacitor, a second detection capacitor, a third detection capacitor and a fourth detection capacitor, wherein the first detection capacitor and the second detection capacitor, and the third detection capacitor and the first detection capacitor The four detection capacitors all constitute the differential capacitance for X-axis inertial signal detection, and the first detection capacitor and the fourth detection capacitor, and the second detection capacitor and the third detection capacitor all constitute the Y-axis inertial signal detection of differential capacitance.

Preferably, the part of the mass block located on one side of the X-axis is provided with a lightening hole, so that the mass of the mass block located on both sides of the X-axis is not equal.

Preferably, the mass block is provided with matching holes at positions corresponding to the fixed electrodes, and the fixed electrodes extend upward into the corresponding matching holes.

Preferably, the four fixed electrodes of the fixed electrode group are symmetrically arranged with respect to the X axis and the Y axis.

Preferably, the substrate is provided with one fixed electrode group.

According to the second aspect of the present invention, an inertial measurement system is provided, which includes a detection unit and any one of the above-mentioned inertial measurement devices, wherein the first detection capacitor and the second detection capacitor are in the The change direction of the mass block is consistent when it is translated along the Y-axis direction, and the change direction of the first detection capacitance and the fourth detection capacitance are consistent when the mass block rotates around the anchor portion; the mass block acts as a The moving electrode is connected to the modulation signal input end;

The detection unit includes a differential processing circuit, a control circuit, and four Y-axis detection switches corresponding to each fixed electrode group and four X-axis detection switches corresponding to each fixed electrode group; the first detection capacitor One branch of the fixed electrode is connected to the first input end of the differential processing circuit through the first Y-axis detection switch, and the other branch is connected to the second input end of the differential processing circuit through the first X-axis detection switch; One branch of the fixed electrode of the second detection capacitor is connected to the first input end through the second Y-axis detection switch, and the other branch is connected to the first input end through the second X-axis detection switch; One branch of the fixed electrodes of the three detection capacitors is connected to the second input end through the third Y-axis detection switch, and the other branch is connected to the first input end through the third X-axis detection switch; the fourth detection One branch of the fixed electrode of the capacitor is connected to the second input end through the fourth Y-axis detection switch, and the other branch is connected to the second input end through the fourth X-axis detection switch;

The control circuit is configured to output a Y-axis detection switch signal to all Y-axis detection switches, and to output an X-axis detection switch signal to all X-axis detection switches, and the Y-axis detection switch signal is consistent with the X The axis detection switch signal causes the Y-axis detection switch and the X-axis detection switch to be turned on time-sharingly.

Preferably, the Y-axis detection switch and the X-axis detection switch are identical switches.

Preferably, both the Y-axis detection switch signal and the X-axis detection switch signal are PWM signals.

Preferably, there is a fixed time delay between the effective level of the Y-axis detection switch signal and the adjacent effective level of the X-axis detection switch signal, wherein the effective level of the Y-axis detection switch signal Level is the level at which the Y-axis detection switch is closed, and the active level of the X-axis detection switch signal is the level at which the X-axis detection switch is closed.

Preferably, the cycle and duty cycle of the Y-axis detection switch signal and the X-axis detection switch signal are the same.

The inertial measurement device and inertial measurement system of the present invention can realize the detection of X-axis and Y-axis inertial signals by sharing the four fixed electrodes of each fixed electrode group. When there is an acceleration input in the Y-axis direction, the mass block will be Translational movement occurs in the Y-axis direction, therefore, the first detection capacitor is connected in parallel with the second detection capacitor, and the third detection capacitor is connected in parallel with the third detection capacitor to realize the detection of the acceleration in the Y-axis direction; and when there is When the acceleration is input, the mass block will rotate around the anchoring part. Therefore, the detection of acceleration in the X-axis direction can be realized by connecting the first detection capacitor and the fourth detection capacitor in parallel, and connecting the second detection capacitor and the third detection capacitor in parallel. Because the inertial measurement device of the present invention can realize the detection of the X-axis and Y-axis inertial signals by sharing four fixed electrodes of each fixed electrode group, it can improve sensitivity under the same chip area, and the same sensitivity In this case, the chip area can be saved, which is conducive to the miniaturization design of the chip.

The inventors of the present invention have found that in the prior art, since it is necessary to arrange independent pairs of fixed electrodes in the X-axis direction and the Y-axis direction, if higher sensitivity is to be obtained, the fixed electrodes will consume chip area. Relatively large problems are not conducive to the control of chip size. Therefore, the technical tasks to be achieved or the technical problems to be solved by the present invention are never thought of or expected by those skilled in the art, so the present invention is a new technical solution.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a schematic structural view of an embodiment of an inertial measurement device according to the present invention;

Fig. 2 is a schematic structural view of another embodiment of the inertial measurement device according to the present invention;

Fig. 3 is a schematic circuit diagram of an implementation of inertial signal detection by the inertial measurement system of the present invention;

Fig. 4 is the equivalent circuit schematic diagram that utilizes the circuit structure shown in Fig. 3 to carry out Y-axis inertial signal detection;

Fig. 5 is a schematic diagram of an equivalent circuit for detecting an X-axis inertial signal using the circuit structure shown in Fig. 3;

FIG. 6 is a timing diagram of an embodiment of the Y-axis detection switch signal and the X-axis detection switch signal corresponding to the circuit structure shown in FIG. 3 .

Explanation of reference signs:

1-mass block; 101-weight reduction hole;

102-cooperating holes; 2, 2a, 2b, 2c, 2d-fixed electrodes;

C12a-the first detection capacitor; C12b-the second detection capacitor;

C12c-the third detection capacitor; C12d-the fourth detection capacitor;

3-anchor part; M0-structure center;

4-elastic torsion beam; Vin2-the second input terminal of the differential processing circuit;

U1-differential processing circuit; Vin1-the first input terminal of the differential processing circuit;

K1a-the first Y-axis detection switch; Vout-the output terminal of the differential processing circuit;

K1b-the second Y-axis detection switch; K1c-the third Y-axis detection switch;

K1d-the fourth Y-axis detection switch; K2a-the first X-axis detection switch;

K2b-second X-axis detection switch; K2c-third X-axis detection switch;

K2d-the fourth X-axis detection switch; Vm-modulation signal;

Pk1-Y-axis detection switch signal; Pk2-X-axis detection switch signal.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that 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 invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and in no way taken as limiting the invention, its application or uses.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the description.

In all examples shown and discussed herein, any specific values should be construed as exemplary only, and not as limitations. Therefore, other instances of the exemplary embodiment may have different values.

It should be noted that like numerals and letters denote like items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

The present invention provides a new inertial measurement device in order to solve the problem that the fixed electrode in the existing inertial measurement device and the corresponding inertial measurement system consumes a large chip area, as shown in Figure 1, the inertial measurement device of the present invention Including a substrate (not shown in the figure), a mass block 1 located above the substrate and an anchor portion 3 fixed on the substrate, the anchor portion 3 is located at the structural center M0 of the mass block 1, and the mass block 1 passes through Two elastic torsion beams 4 extending along the X axis are connected to the anchoring part 3, specifically, the mass block 1 is connected to the side wall of the anchoring part 3 through two elastic torsion beams 4, and the two elastic torsion beams 4 are about The Y axis is symmetrical, and the extension of the elastic torsion beam 4 along the X axis here should be understood as the centerline of the elastic torsion beam 4 coincides with the X axis; wherein, the X axis and the Y axis are perpendicular to each other on the plane where the mass block 1 is located, and both After passing through the structure center M0, that is, the X axis and the Y axis intersect at the structure center MO; the mass of the mass block 1 on both sides of the Y axis is equal, and the mass of the parts on both sides of the X axis is not equal. The above structure makes the mass block 1 sensitive in the following way: when there is an acceleration input along the X-axis direction, since the anchoring part 3 is located at the structural center M0 of the mass block 1, the elastic torsion beam 4 extends along the X-axis direction, and the mass block The masses of the parts on both sides of the X-axis of 1 are not equal, so that the entire mass 1 will rotate with the anchor part 2 as the fulcrum, so that it is sensitive to the acceleration signal in the direction of the X-axis; When the acceleration is input, since the anchor part 3 is located at the structural center M0 of the mass block 1, the elastic torsion beam 4 extends along the X-axis direction, so that the entire mass block 1 will undergo a translational movement in the Y-axis direction, so that it will move to the Y-axis direction The acceleration signal is sensitive.

On the basis of the above structure, the inertial measurement device of the present invention also includes at least one fixed electrode group arranged on the substrate, and the fixed electrode group has four fixed electrodes 2, which are respectively fixed electrode 2a, fixed electrode 2b, fixed electrode 2c and Fixed electrode 2d, the mass 1 forms a first detection capacitor C12a with the fixed electrode 2a as a common movable electrode, forms a second detection capacitor C12b with the fixed electrode 2b, forms a third detection capacitor C12c with the fixed electrode 2c, and forms a third detection capacitor C12c with the fixed electrode 2c. The electrode 2d forms a fourth detection capacitor C12d; wherein, for the four detection capacitors C12a, C12b, C12c, and C12d formed by the same fixed electrode group, the first detection capacitor C12a, the second detection capacitor C12b, and the third detection capacitor C12c Together with the fourth detection capacitor C12d, they constitute the differential capacitance for X-axis inertial signal detection, that is, the first detection capacitor C12a and the second detection capacitor C12b, and the third detection capacitor C12c and the fourth detection capacitor C12d around the anchor portion of the mass block 1 3 The change amount during rotation is equal, and the change direction is opposite; the first detection capacitor C12a and the fourth detection capacitor C12d, and the second detection capacitor C12b and the third detection capacitor C12c all constitute the differential capacitance for Y-axis inertial signal detection, that is, the first The change amounts of the first detection capacitor C12a and the fourth detection capacitor C12d, and the second detection capacitor C12b and the third detection capacitor C12c are equal when the proof mass 1 translates along the Y-axis direction, and the change directions are opposite. Fig. 1 shows an alternative embodiment in which one fixed electrode group is arranged on the substrate, and when more than two fixed electrode groups are arranged, it only needs to be configured according to the above requirements.

Utilizing the inertial device of the present invention needs to perform time-sharing detection of the X-axis and Y-axis inertial signals, and the direction of change of the first detection capacitor C12a and the second detection capacitor C12b shown in FIG. 1 is consistent when the proof mass 1 translates along the Y-axis direction. , and the changing directions of the first detection capacitance C12a and the fourth detection capacitance C12d are consistent when the mass 1 rotates around the anchor portion 3 as an example, the time-sharing detection principle is:

When detecting the Y-axis inertial signal, connect all the first detection capacitors C12a and all the second detection capacitors C12b in parallel to obtain an equivalent detection capacitor CY1, and connect all the third detection capacitors C12c and all the fourth detection capacitors C12d in parallel, The equivalent detection capacitance CY2 is obtained, that is, the detection capacitances that change in the same direction when the proof mass 1 translates along the Y-axis direction are connected in parallel; since the first detection capacitance C12a and the fourth detection capacitance C12d, and the second detection capacitance C12b and the third detection capacitance Both detection capacitors C12c constitute differential capacitances for Y-axis inertial signal detection, therefore, the equivalent detection capacitors CY1 and CY2 will constitute differential capacitances for Y-axis inertial signal detection. Here, since the first detection capacitor C12a and the second detection capacitor C12b, and the third detection capacitor C12c and the fourth detection capacitor C12d all constitute the differential capacitance for X-axis inertial signal detection, therefore, when the first detection capacitor C12a and the second After the two detection capacitors C12b are connected in parallel, the capacitance changes of the first detection capacitor C12a and the second detection capacitor C12b due to acceleration in the X-axis direction will cancel each other, so that the equivalent detection capacitor CY1 remains unchanged. Similarly, when the third detection capacitor After C12c and the fourth detection capacitor C12d are connected in parallel, the capacitance changes of the third detection capacitor C12c and the fourth detection capacitor C12d due to the acceleration in the X-axis direction will cancel each other, so that the equivalent detection capacitor CY2 remains unchanged, all of which can be guaranteed in It is not sensitive to acceleration in the X-axis direction when performing Y-axis inertial signal detection.

When detecting the X-axis inertial signal, connect all the first detection capacitors C12a and all the fourth detection capacitors C12d in parallel to obtain an equivalent detection capacitor CX1, and connect all the second detection capacitors C12b and all the third detection capacitors C12c in parallel, The equivalent detection capacitance CX2 is obtained, that is, the detection capacitances that change in the same direction when the mass 1 rotates around the anchor portion 3 are connected in parallel; since the first detection capacitance C12a and the second detection capacitance C12b, and the third detection capacitance C12c and the first detection capacitance The four detection capacitors C12d all constitute differential capacitances for X-axis inertial signal detection. Therefore, the equivalent detection capacitors CX1 and CX2 will constitute differential capacitances for X-axis inertial signal detection. Here, since the first detection capacitor C12a and the fourth detection capacitor C12d, and the third detection capacitor C12c and the second detection capacitor C12b all constitute the differential capacitance for Y-axis inertial signal detection, therefore, the first detection capacitor C12a and the second detection capacitor After the four detection capacitors C12d are connected in parallel, the capacitance changes of the first detection capacitor C12a and the fourth detection capacitor C12d due to acceleration in the Y-axis direction will cancel each other, so that the equivalent detection capacitor CX1 remains unchanged. Similarly, when the third detection capacitor After C12c is connected in parallel with the second detection capacitor C12b, the capacitance changes of the third detection capacitor C12c and the second detection capacitor C12b due to the acceleration in the Y-axis direction will cancel each other out, so that the equivalent detection capacitor CX2 remains unchanged, all of which can be guaranteed in It is insensitive to acceleration in the Y-axis direction when detecting the X-axis inertial signal.

It can be seen that the inertial measurement device of the present invention can realize the detection of X-axis and Y-axis inertial signals by sharing the four fixed electrodes of each fixed electrode group, so it can improve the sensitivity under the same chip area. In the case of the same sensitivity, the chip area can be saved, which is beneficial to the miniaturization design of the chip.

In a specific embodiment of the present invention, in order to make the mass of the mass block 1 on both sides of the X-axis unequal, a weight reduction hole 101 can be provided on the mass block 1 on the side of the X-axis. There may be multiple lightening holes 101 distributed in a matrix. The weight reducing hole 101 can be a through hole, which can be formed by etching during manufacture; it can also be a blind hole, which can be etched by adding a layer of mask. In another specific embodiment of the present invention, it is also possible to increase the mass of the mass block 1 on both sides of the X-axis to be unequal by adding a counterweight.

In the embodiment in which the masses of the parts on both sides of the X-axis of the mass block 1 are unequal by setting the weight-reducing holes 101, in order to make the masses of the parts of the mass block 1 on both sides of the Y-axis equal, preferably the weight-reducing holes 101 is arranged symmetrically about the Y axis, which can make the centroids of the parts of the proof mass 1 on both sides of the Y axis symmetrical about the Y axis, thereby further improving the measurement accuracy of the inertial measurement device. Similarly, in the embodiment in which the masses of the parts on both sides of the X-axis of the mass 1 are unequal by adding counterweights, in order to make the masses of the parts of the mass 1 on both sides of the Y-axis equal, it is preferable to make the mass 1 The weights are arranged symmetrically about the Y axis.

In the inertial measurement device of the present invention, the fixed plate 2 may adopt a capacitive plate mechanism well known to those skilled in the art. In a specific embodiment of the present invention, each fixed pole plate 2 can be distributed on the outer periphery of the mass block 1 to form detection capacitors with the side wall of the mass block 1 respectively. In another specific embodiment of the present invention, a hollow fitting hole 102 is provided on the mass 1 for the position of the fixed electrode 2, and the fixed electrode 2 extends upward into the corresponding fitting hole 102, so that the fixed electrode 2 and the fitting hole The side wall of 102 forms a detection capacitor. Here, a structure in which the matching holes 102 and the fixed electrodes 2 are arranged in one-to-one correspondence as shown in FIG. Structure of Electrode 2.

In a specific embodiment of the present invention, in order to facilitate the design of a fixed electrode group satisfying the above conditions, the four fixed electrodes 2 may be arranged symmetrically about the X axis and the Y axis. In this regard, the first detection capacitor C12a and the second detection capacitor C12b, and the third detection capacitor C12c and the fourth detection capacitor C12d all constitute differential capacitances for X-axis inertial signal detection. The first detection capacitor C12a and the fourth detection capacitor On the basis of C12d, the second detection capacitor C12b and the third detection capacitor C12c all constituting the differential capacitance for Y-axis inertial signal detection, the first detection capacitor C12a and the third detection capacitor C12c, and the second detection capacitor C12b and the first detection capacitor C12b are realized. The four detection capacitors C12d all constitute the design of differential capacitors for X-axis and Y-axis inertial signal detection.

In another specific embodiment of the present invention, if an even number of fixed electrode groups is set, all fixed electrode groups are arranged symmetrically about the X axis; if an odd number of fixed electrode groups is set, four fixed electrode groups of one of the fixed electrode groups are arranged The electrodes 2 are arranged symmetrically about the X-axis and the Y-axis, and the remaining even-numbered fixed electrode groups are arranged symmetrically about the X-axis.

Since the inertial measurement device of the present invention detects the X-axis and Y-axis inertial signals through the differential capacitance formed by the parallel connection of two fixed plates, therefore, the inertial device of the present invention is provided with a fixed electrode group Higher measurement sensitivity can be obtained, and compared with existing inertial devices capable of obtaining the same sensitivity, it can have a smaller size, which is beneficial to the miniaturization of inertial devices.

Since the inertial measurement device of the present invention only involves the improvement of X-axis and Y-axis inertial signal detection, the setting and detection method of the Z-axis detection capacitor perpendicular to the X-axis and Y-axis are not described. However, it is clear to those skilled in the art that if Z-axis inertial signal detection is required, a Z-axis detection capacitor can be formed on the basis of the inertial measurement device of the present invention to detect the Z-axis inertial signal alone, which can be used in the lining The Z-axis fixed electrode is arranged on the bottom, so that it forms a Z-axis detection capacitor with the mass block 1. In this way, when the external acceleration along the Z-axis direction is input, since the anchoring part 3 is located at the structural center M0 of the mass block 1, the elastic torsion The beam 4 extends along the X-axis direction, and the mass of the mass block 1 on both sides of the X-axis is not equal, so that the entire mass block 1 will swing around the X-axis with the anchor portion 2 as a fulcrum, forming a seesaw swing structure, so that It is sensitive to the acceleration signal in the Z-axis direction; in addition, it can also detect the Z-axis inertial signal by configuring a single-axis accelerometer separately.

On the basis of the above-mentioned inertial measurement device, in order to directly output X-axis and Y-axis inertial signals without additionally configuring related circuits for obtaining X-axis and Y-axis inertial signals during use, the present invention also provides a method such as Inertial measurement system shown in Fig. 3, it comprises detection unit and inertial measurement device of the present invention, the mass block 1 of this inertial measurement device is connected with modulation signal input end as movable electrode, to receive the modulation that is input through modulation signal input end signal Vm; the detection unit includes a differential processing circuit U1, a control circuit, and four Y-axis detection switches corresponding to the fixed electrode groups and four X-axis detection switches corresponding to the fixed electrode groups, that is, each fixed electrode group has Corresponding four Y-axis detection switches and four X-axis detection switches. As shown in FIG. 3 , in the fixed electrode group, the change directions of the first detection capacitance C12a and the second detection capacitance C12b are consistent when the proof mass 1 is translated along the Y-axis direction, and the first detection capacitance C12a and the fourth detection capacitance C12d are in the same direction. When the changing direction of the mass 1 when it rotates around the anchor portion 3 is arranged in the same way, a branch of the fixed electrode 2a of the first detection capacitor C12a is connected to the first input terminal Vin1 of the differential processing circuit U1 through the first Y-axis detection switch K1a , the other branch is connected to the second input terminal Vin2 of the differential processing circuit U1 through the first X-axis detection switch K2a; a branch of the fixed electrode 2b of the second detection capacitor C12b is connected to the first input terminal through the second Y-axis detection switch K1b Terminal Vin1 is connected, and the other branch is connected to the first input terminal Vin2 through the second X-axis detection switch K2b; a branch of the fixed electrode 2c of the third detection capacitor C12c is connected to the second input terminal Vin2 through the third Y-axis detection switch K1c The other branch is connected to the first input terminal Vin1 through the third X-axis detection switch K2c; a branch of the fixed electrode 2d of the fourth detection capacitor C12d is connected to the second input terminal Vin2 through the fourth Y-axis detection switch K1d, The other branch is connected to the second input terminal Vin2 through the fourth X-axis detection switch K2d; wherein, the first input terminal Vin1 and the second input terminal Vin2 are the positive and negative input terminals of the differential processing circuit, and the first input terminal Vin1 can be a positive input terminal or a negative output terminal. The control circuit is configured to output a Y-axis detection switch signal Pk1 to all Y-axis detection switches, and to output an X-axis detection switch signal Pk2 to all X-axis detection switches, and the Y-axis detection switch signal Pk1 is consistent with the X-axis detection switch. The switch signal Pk2 causes the Y-axis detection switch and the X-axis detection switch to be turned on time-sharingly.

The differential processing circuit can adopt the existing differential processing circuit that uses the principle of differential capacitance to detect inertial signals. The differential processing circuit usually includes a differential amplifier circuit, a demodulation circuit and a filter circuit. Here, since the differential processing circuit itself is not the original The improvement point of the invention, so its specific structure will not be described in detail.

Figure 4 shows that when the Y-axis detection switch signal Pk1 controls all the Y-axis detection switches K1a, K1b, K1c, and K1d to close, and the X-axis detection switch signal PK2 controls all the X-axis detection switches K2a, K2b, K2c, and K2d to open In this structure, the first detection capacitor C12a and the second detection capacitor C12b are connected in parallel to the first input terminal Vin1 of the differential processing circuit U1, and the third detection capacitor C12c and the fourth detection capacitor C12d are connected in parallel to the differential The differential output mode of the second input terminal Vin2 of the processing circuit U1, therefore, referring to the above description, it can be seen that this structure can detect the inertial signal in the Y-axis direction, which means that when the movable electrode receives the modulation signal Vm, the differential processing The output terminal Vout of the circuit U1 will output the inertial signal in the Y-axis direction.

Figure 5 shows that when the Y-axis detection switch signal Pk1 controls all the Y-axis detection switches K1a, K1b, K1c, and K1d to be turned off, and the X-axis detection switch signal PK2 controls all the X-axis detection switches K2a, K2b, K2c, and K2d to be closed In this structure, the first detection capacitor C12a and the fourth detection capacitor C12d are connected in parallel to the second input terminal Vin2 of the differential processing circuit U1, and the third detection capacitor C12c and the second detection capacitor C12b are connected in parallel to the differential The differential output mode of the first input terminal Vin1 of the processing circuit U1, therefore, referring to the above description, it can be seen that this structure can detect the inertial signal in the X-axis direction, which means that when the movable electrode receives the modulation signal Vm, the differential processing The output terminal Vout of the circuit U1 will output an inertial signal in the X-axis direction.

The above-mentioned Y-axis detection switch and X-axis detection switch can use field effect transistors or triodes to facilitate the integration of detection units on the chip, and the field effect transistors are preferably metal-oxide semiconductor field effect transistors (MOSFETs). For field effect transistors, the Y-axis detection switch signal Pk1 and the X-axis detection switch signal Pk2 can control the on-off status of the Y-axis detection switch and the X-axis detection switch through their grids; for the triode, the Y-axis detection switch signal Pk1 and X The axis detection switch signal Pk2 can control the on-off state of the Y-axis detection switch and the X-axis detection switch through its base correspondingly.

As shown in Figure 6, the above-mentioned Y-axis detection switch signal Pk1 and X-axis detection switch signal Pk2 can both be PWM signals, so that the control circuit can be realized by using a single-chip microcomputer or FPGA, etc., specifically to divide the frequency of the clock signal connected to the chip , and use the timer to adjust the duty cycle to obtain the corresponding Y-axis detection switch signal Pk1 and X-axis detection switch signal Pk2.

When the effective level of the Y-axis detection switch signal is consistent with the effective level of the X-axis detection switch signal, the X-axis detection switch signal can be obtained by inverting the Y-axis detection switch signal through an inverter, wherein, The effective level of the Y-axis detection switch signal is the level at which the Y-axis detection switch is closed, and the effective level of the X-axis detection switch signal is the level at which the X-axis detection switch is closed. Therefore, the effective level depends on Selection of X-axis detection switch and Y-axis detection switch.

In order to avoid the problem that the X-axis detection switch and the Y-axis detection switch are closed at the same time due to parameter differences, as shown in Figure 6, it is preferable that the effective level of the Y-axis detection switch signal is adjacent to the effective level of the X-axis detection switch signal. A fixed time delay ΔT is set between the levels. The time delay ΔT is usually at the level of microseconds or even nanoseconds, which can prevent the X-axis detection switch and the Y-axis detection switch from being closed at the same time. Therefore, the time delay ΔT can be obtained by adding an even number of inverters , that is, the time delay ΔT is obtained through the action time of multiple CMOS devices. If a longer time delay is required, it can also be achieved by a phase shifter.

In order to facilitate the formation of the Y-axis detection switch signal and the X-axis detection switch signal that meet the time-sharing detection conditions, in a specific embodiment of the present invention, the Y-axis detection switch and the X-axis detection switch are completely the same switch. The same includes the same types and parameters, which can make the Y-axis detection switch and the X-axis detection switch have basically the same switching characteristics within the range of error tolerance, thereby reducing the required time delay ΔT to the minimum.

In order to facilitate subsequent circuit analysis of the X-axis and Y-axis inertial signals, as shown in Figure 6, the Y-axis detection switch signal Pk1 and the X-axis detection switch signal Pk2 preferably have the same period (periods are both T), and the duty cycle is also the same the PWM signal. Further, the active level of the Y-axis detection switch signal Pk1 is preferably consistent with the active level of the X-axis detection switch signal Pk2 , for example, both are high level.

The above-mentioned embodiments mainly focus on describing differences from other embodiments, but those skilled in the art should be clear that the above-mentioned embodiments can be used alone or in combination with each other as required.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and not intended to limit the scope of the present invention. Those skilled in the art will appreciate that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims (10)

1. An inertial measurement device, characterized in that: comprise a substrate, a mass (1) positioned above the substrate and an anchor portion (3) fixed on the substrate, the anchor portion (3) Located at the structural center (M0) of the mass block (1), the mass block (1) is connected to the anchor portion (3) through two elastic torsion beams (4) extending along the X axis, and the The two elastic torsion beams (4) are symmetrical about the Y axis, wherein the X axis and the Y axis are perpendicular to each other on the plane where the mass block (1) is located, and both pass through the structure center (M0); The mass of the mass block (1) on both sides of the Y axis is equal, and the mass of the parts on both sides of the X axis is not equal; The inertial measurement device also includes at least one fixed electrode group arranged on the substrate, the fixed electrode group has four fixed electrodes (2), and the mass block (1) is used as a movable electrode to communicate with the fixed electrode group. The four fixed electrodes (2) of the electrode group respectively form the first detection capacitance (C12a), the second detection capacitance (C12b), the third detection capacitance (C12c) and the fourth detection capacitance (C12d), wherein the first detection capacitance (C12a) and the second detection capacitance (C12b), and the third detection capacitance (C12c) and the fourth detection capacitance (C12d) all constitute a differential capacitance for X-axis inertial signal detection, and the first The detection capacitor (C12a) and the fourth detection capacitor (C12d), and the second detection capacitor (C12b) and the third detection capacitor (C12c) all constitute differential capacitances for Y-axis inertial signal detection. 2. The inertial measurement device according to claim 1, characterized in that: the part of the mass (1) on one side of the X-axis is provided with a lightening hole (101), so that the mass (1) The parts on either side of the x-axis have unequal masses. 3. The inertial measurement device according to claim 1, characterized in that, the mass block (1) is provided with a matching hole (102) at a position corresponding to the fixed electrode (2), and the fixed electrode (2) ) into the corresponding matching hole (102). 4. The inertial measurement device according to claim 1, characterized in that, the four fixed electrodes (2) of the fixed electrode group are symmetrically arranged with respect to the X axis and the Y axis. 5. The inertial measurement device according to any one of claims 1 to 4, wherein the substrate is provided with one fixed electrode group. 6. An inertial measurement system, characterized in that it comprises a detection unit and the inertial measurement device according to any one of claims 1 to 5, wherein the first detection capacitance (C12a) and the second detection capacitance (C12b) When the mass block (1) is translated along the Y-axis direction, the direction of change is the same, and the first detection capacitance (C12a) and the fourth detection capacitance (C12d) are in the mass block (1) The direction of change when rotating around the anchor part (3) is the same; the mass block (1) is used as a movable electrode and connected to the modulation signal input end; The detection unit includes a differential processing circuit (U1), a control circuit, four Y-axis detection switches corresponding to the fixed electrode groups, and four X-axis detection switches corresponding to the fixed electrode groups; the first One branch of the fixed electrode (2a) of the detection capacitor (C12a) is connected to the first input terminal (Vin1) of the differential processing circuit (U1) through the first Y-axis detection switch (K1a), and the other branch is connected through the first The X-axis detection switch (K2a) is connected to the second input terminal (Vin2) of the differential processing circuit (U1); a branch of the fixed electrode (2b) of the second detection capacitor (C12b) passes through the second Y-axis detection The switch (K1b) is connected to the first input terminal (Vin1), and the other branch is connected to the first input terminal (Vin1) through the second X-axis detection switch (K2b); the third detection capacitor (C12c ) one branch of the fixed electrode (2c) is connected to the second input terminal (Vin2) through the third Y-axis detection switch (K1c), and the other branch is connected to the first input terminal (Vin2) through the third X-axis detection switch (K2c) One input terminal (Vin1) is connected; one branch of the fixed electrode (2d) of the fourth detection capacitor (C12d) is connected to the second input terminal (Vin2) through the fourth Y-axis detection switch (K1d), and the other The branch is connected to the second input terminal (Vin2) through the fourth X-axis detection switch (K2d); The control circuit is configured to output a Y-axis detection switch signal (Pk1) to all Y-axis detection switches (K1a, K1b, K1c, K1d) and to output a Y-axis detection switch signal (Pk1) to all X-axis detection switches (K2a, K2b, K2c, K2d) output the X-axis detection switch signal (Pk2), and the Y-axis detection switch signal (Pk1) and the X-axis detection switch signal (Pk2) make the Y-axis detection switches (K1a, K1b, K1c, K1d) and the X-axis detection switches (K2a, K2b, K2c, K2d) are time-divisionally closed. 7. The inertial measurement system according to claim 6, characterized in that, the Y-axis detection switches (K1a, K1b, K1c, K1d) and the X-axis detection switches (K2a, K2b, K2c, K2d) are completely Same switch. 8. The inertial measurement system according to claim 6, characterized in that, both the Y-axis detection switch signal (Pk1) and the X-axis detection switch signal (Pk2) are PWM signals. 9. The inertial measurement system according to claim 8, characterized in that, between the effective level of the Y-axis detection switch signal (Pk1) and the adjacent effective level of the X-axis detection switch signal (Pk2) There is a fixed time delay (ΔT) between them, wherein the active level of the Y-axis detection switch signal (Pk1) is a level that makes the Y-axis detection switches (K1a, K1b, K1c, K1d) closed, and the The effective level of the X-axis detection switch signal ( Pk2 ) is a level at which the X-axis detection switches ( K2 a , K2 b , K2 c , K2 d ) are closed. 10. The inertial measurement system according to claim 8, characterized in that, the Y-axis detection switch signal (Pk1) and the X-axis detection switch signal (Pk2) have the same cycle and the same duty cycle.