JPH03276072A - Signal processing circuit for acceleration detecting device - Google Patents

Abstract

PURPOSE:To obtain a correct measured value by finding the reverse matrix of a characteristic matrix showing the state of interference caused between axial components in advance and carrying out correction arithmetic operation using this reverse matrix by an analog arithmetic circuit. CONSTITUTION:Such coefficients K11 - K13, K21 - K23, and K31 - K33 that Ax=K11Vx+K12Vy+K13Vz, Ay=K21Vx+K22Vy+K23Vz, and Az=K31Vx+ K32Vy+K33Vz are hold are found, where Ax, Ay, and Az are the X-axial component, Y-axial component, and Z-axial component of an external force operating on an operation point and Vx, Vy, and Vz are voltage values obtained according to a bridge circuit consisting of plural resistance elements. Then the values of the terms in the right members of the relational expressions are calculated by using analog multipliers 101 - 109 and the right members are added by using analog adders 111 - 113 to obtain the detected values Ax, Ay, and Az from the arithmetic results.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a signal processing circuit for an acceleration detection device, particularly an acceleration detection device that detects acceleration in two-dimensional or three-dimensional directions using a resistance element exhibiting a piezoresistive effect. The present invention relates to a signal processing circuit suitable for devices.

[Conventional technology]

The development of various sensors is important for the automation of industrial equipment. As one such sensor, a force detection device has been proposed that detects force in a two-dimensional or three-dimensional direction using a resistance element exhibiting a piezoresistance effect. This force detection device can detect the direction and magnitude of an external force applied to a predetermined point of action from a change in the resistance value of a resistance element formed on a single crystal substrate. If a weight body is formed at this point of action, the acceleration acting on the weight body can be detected as a force, so that it can also be applied as an acceleration detection device. Furthermore, if a magnetic material is formed at the point of action, the magnetism acting on the magnetic material can be detected as a force, and therefore it can also be applied as a magnetic detection device. For example, Japanese Patent Application Laid-Open No. 1-263576 discloses a magnetic detection device and an acceleration detection device to which such a force detection device is applied.

[Problem to be solved by the invention]

However, conventional acceleration detection devices (or force detection devices and magnetic detection devices based on the same principle) have a problem in that interference occurs in output characteristics in two-dimensional or three-dimensional axial directions. For example, in a three-dimensional acceleration detection device, each of the X-axis direction component, Y-axis direction component, and Z-axis direction component of acceleration acting on a predetermined point of action must be detected independently. However, in conventional detection devices, these axial components interfere with each other, and the detected value of one axial component is influenced to some extent by the detected value of the other axial component.

Such interference is undesirable because it reduces the reliability of measured values.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a signal processing circuit for an acceleration detection device that can obtain accurate detection values that are free from interference from components in other axis directions.

[Means to solve the problem]

(L) The invention in Box 1 arranges a plurality of resistance elements exhibiting a piezoresistance effect in which electrical resistance changes due to mechanical deformation on a single crystal substrate, and applies acceleration to a predetermined point of action in an XYZ three-dimensional coordinate system. When an external force is applied, this external force causes mechanical deformation on the single crystal substrate, and the X-axis direction component Ax, Y-axis direction component Ay, and Z-axis direction component Az of the external force acting on the point of application are In a signal processing circuit for an acceleration detection device that detects voltage values VxSVy, Vz obtained based on a bridge circuit configured of resistive elements, there is a
-KlIVx + to 12Vy + to 13VzAy =K
21Vx + to 22Vy + 23VzAz = K31
Coefficients Kll, K12°K13. such that the relational expression of 32Vy + 33Vz holds true for Vx +. K21.
K22. K23. K31. K32
Find K33, calculate the value of the term on the right side of the relational expression using an analog multiplier, add the right side of the relational expression using an analog adder, and calculate the detected value AX SA from these calculation results.
It is configured to obtain y and Az.

(2) The invention in Box 2 arranges a plurality of resistance elements exhibiting a piezoresistance effect in which electrical resistance changes due to mechanical deformation on a single crystal substrate, and applies an external force due to acceleration to a predetermined point of application. Then, this external force causes mechanical deformation in the single crystal substrate, and the X-axis direction component Ax of the external force acting on the point of application and the Y-axis direction component AV orthogonal to this are
between Ax, Ay and Vx, Vy in a signal processing circuit for an acceleration detection device that detects the voltage based on the respective bridge voltage values Vx and Vy of two sets of bridge circuits constituted by a plurality of resistance elements. AX = K11Vx + 12Vy Ay = 21Vx + 22V)' Coefficients Kll, KL2゜K
21. Find K22, calculate the value of the term on the right side of the relational expression using an analog multiplier, add the right side of the relational expression using an analog adder, and calculate the detected value A from these calculation results.
It is configured to obtain x and Ay.

[For production]

According to the signal processing circuit for an acceleration detection device of the present invention, a characteristic matrix indicating the state of interference occurring between each axial component and an inverse characteristic matrix, which is the inverse matrix thereof, are obtained in advance. Then, by performing a correction calculation using this inverse characteristic matrix, the influence of interference can be canceled out. Furthermore, since all of this correction calculation is performed by an analog calculation circuit, the circuit configuration is simple and the correction circuit can be realized at low cost.

Furthermore, since it is an analog calculation, the calculation speed is high, and there is no problem when measuring instantaneous phenomena.

〔Example〕

Structure of Force Detection Device Before explaining the signal processing circuit according to the present invention, the structure of the acceleration detection device to which this signal processing circuit is applied will be explained. FIG. 1 is a side sectional view of this acceleration detection device, and FIG. 2 is a top sectional view of this device taken along cutting line A-A.

The part that performs the central function of this detection device is the single crystal substrate 1.
It is 0. In this embodiment, a silicon single crystal substrate is used. The single crystal substrate 10 has a disk shape as shown in FIG. 2, and in this specification, the central portion is an acting portion 11, the periphery thereof is a flexible portion 12, and the outer peripheral portion thereof is a fixed portion 13. , I will call it. A cylindrical groove is formed on the lower surface of the substrate, and the flexible portion 12 is a portion located above this groove. Since the groove is formed, the flexible portion 12
is a thin part and has flexibility. A cylindrical pedestal 20 is connected below the fixed part 13, and a cylindrical weight body 30 is connected below the action part 11.

In this embodiment, the weight body 30 is made of glass. Since a silicon substrate is used as the single-crystal substrate 10, it is preferable to use a borosilicate glass such as Pyrex, which has a fat expansion coefficient similar to that of silicon, as the weight body 30. The lower surface of the pedestal 20 is fixed to the bottom surface of the case 40.
0 is covered with a lid 41.

As shown in FIG. 2, a plurality of resistance elements R (Rxl~Rx4°Ryl~R
y4. Rzl to Rz4) are formed. These resistance elements R are resistance elements having a piezoresistance effect in which electrical resistance changes by mechanical deformation, and the flexible portion 12
is placed in a predetermined direction on the top surface of the An external wiring electrode 50 is led out from the inside of the case to the outside so as to pass through a wiring hole on the side surface of the case 40. The internal end of this external wiring electrode 50 is connected to a bonding pad 520M1 (not shown in the figure) provided on the fixed portion 13 of the single crystal substrate 10 by a bonding wire 51.

This bonding pad 52 is connected to the resistance element R by a wiring pattern not shown. therefore,
If the external wiring electrode 50 is electrically connected to an external control device (not shown), a change in the resistance value of the resistance element R can be measured by the external control device.

Now, take the X-axis to the right in Figure 2, the Y-axis to the top, and the Z-axis to the perpendicular direction to the paper (top of the diagram in Figure 1) to form an XYZ three-dimensional coordinate system. Define. In this coordinate system, four resistance elements RXL-Rx4 are arranged on the X-axis and are used to detect the acceleration component in the X-axis direction, and four resistance elements RyL-Ry4 are arranged on the Y-axis.
It is used to detect the acceleration component in the Y-axis direction, and the four resistance elements Rzl to Rz4 are arranged on an axis parallel to and in the vicinity of the X-axis, and are used to detect the acceleration component in the Z-axis direction.

As described above, each of these resistance elements R is electrically connected to an external control device through the external wiring electrode 50. In this control device, a bridge circuit as shown in FIG. 3 is constructed for each resistance element R. That is,
Resistance element Rx1. - For Rx4, a bridge circuit as shown in the same figure (a) is constructed, and resistor elements Ry1 to Ry4
For the resistor elements RzL to Rz4, a bridge circuit as shown in FIG. 5(b) is constructed, and for the resistive elements RzL to Rz4, a bridge circuit as shown in FIG. 2(c) is constructed. Each bridge circuit is supplied with a predetermined voltage or current from a power source 60, and each bridge voltage is measured by an ammeter 61, 62, 63.

As shown in FIG. 1, the weight body 30 is suspended in the central space of the cylindrical base 20. As shown in FIG. When acceleration is applied to the case 40, an external force acts on the weight body 30 due to this acceleration, and the weight body 30 is displaced from its home position. Therefore, the acting part 11 connected to the weight body 30 is also displaced from its normal position, and the mechanical strain caused by this displacement is absorbed by the mechanical deformation of the flexible part 12.

When mechanical deformation occurs in the flexible portion 12, the electrical resistance of the resistance element R formed thereon changes. As a result, the equilibrium condition of the bridge circuit shown in FIG. 3 is disrupted, and the voltmeter 61.
The needle of 62.63 will swing. This is the basic principle of acceleration detection by this device.

Now, if the resistance element R is arranged as shown in Fig. 2, in the bridge circuit shown in Fig. 3, the voltmeter 61 detects the acceleration component in the 63, acceleration components in the X-axis direction can be detected.

The reason for this will be explained below. FIG. 4 is a schematic diagram showing the stress strain applied to each resistance element R when a force Fx in the X-axis direction is applied to the weight body 30 in the apparatus shown in FIG. The figure (a) shows the stress distribution in the cross section along the resistance elements Rxl to Rx4, and the figure (b) shows the stress distribution in the cross section along the resistance elements Rxl to Rx4.
1 to Ry4, and FIG. 1C shows the stress distribution in a cross section along the resistance element Rzl-Rz4.

In the stress distribution, the direction of expansion is indicated by the symbol 10, and the direction of contraction is indicated by the symbol -. For example, FIG. 4(a) shows the resistance elements Rxl to RX when the force Fx in the X direction is applied to the weight body 30.
4 shows the stress distribution in the cross section along 4. The force Fx acting on the weight body 30 acts as a moment force on the surface of the single crystal substrate 10, mechanically deforming the resistance elements RXI and Rx3 in the direction of shrinkage, and causing resistance elements Rx2 and Rx4 to undergo mechanical deformation in the direction of contraction. mechanical deformation occurs in the elongation direction.

On the other hand, for the resistance elements Ry1 to Ry4, the fourth
As shown in Figure (b), the stress does not change. This means that the direction in which the resistance elements RyL-Ry4 are arranged (Y-axis direction) is the force Fx.
This is because it is perpendicular to the direction of. Resistance element Rzl~R
Regarding z4, as shown in FIG. 4(C), the same change occurs as in the resistance elements Rxl to Rx4.

Similarly, FIGS. 5(a) to (c) show the stress distribution generated in each resistance element R when a force Fy in the Y-axis direction is applied, and the stress distribution in each resistance element R when a force Fz in the X-axis direction is applied. The stress distributions occurring in this case are shown in FIGS. 6(a) to 6(C). Here, if a resistance element is used that has a property that its resistance value increases against mechanical deformation in the direction of extension and decreases against mechanical deformation in the direction of contraction, the effect on the weight body 30 The force Fx, F
The relationship between y, Fz and the change in resistance value of each resistance element R is as shown in Table 1 below. Here, the sign 10 is the increase in resistance value,
The sign - indicates a decrease in resistance value, and O indicates no change in resistance value.

Table 1> Referring to Table 1 and the bridge circuit in FIG. 3, the voltmeter 61 detects the force Fx, the voltmeter 62 detects the force Fy, and the voltmeter 63 detects the force Fz. You can understand that.

For example, when force FX is applied, in the bridge circuit shown in FIG. 3(a), the resistance value on one opposite side increases, and the resistance value on the other opposite side decreases, so that the needle of the voltmeter 61 swings. become. However, in the bridge circuit of FIG. 3(b), there is no change in any of the resistance values, so the needle of the voltmeter 62 does not swing, and in the bridge circuit of FIG. 3(C),
One of the resistors forming each opposite side increases in resistance value, and the other side decreases in resistance value, and eventually they cancel each other out, so that the needle of the voltmeter 63 does not swing. In this way, each direction component of the acceleration acting on the main body of the device is detected as the deflection of the needles of the voltmeters 61 to 63.

Although this embodiment has been described as a three-dimensional acceleration detection device that detects acceleration direction components of all three axes of XYZ, a two-dimensional acceleration detection device that detects acceleration direction components of two axes such as XYSYZ or XZ may also be used. It can be configured similarly.

In this case, resistance elements and bridge circuits need only be prepared for two axes. In addition, although an example was shown in which three sets of bridges are used to detect acceleration components in each of the three axial directions, a device that uses two sets of bridges to detect acceleration components in each of the three axial directions (for example, US Patent No. 47
No. 45812), the present invention can also be applied to. In addition, although the acceleration detection device has been explained here as an example, if a magnetic body is used instead of the weight body 30, this device becomes a magnetic detection device that detects the magnetism acting on the magnetic body, and the weight body 30 If the structure is such that an external force acts directly on it, it becomes a force detection device.

Signal Processing Circuit Next, the signal processing circuit according to the present invention will be explained. As mentioned above, the force to be detected (or acceleration or magnetism) is detected in the bridge circuit shown in FIG. The Z-axis direction component is detected by the voltage value Vy at 62 and the voltage value Vz at the voltmeter 63, respectively. Note that in a device that detects acid content in three axial directions using two sets of bridges, the voltage values obtained by performing calculations based on the bridge voltages are used as Vx, Vy, and Vz, rather than the bridge voltage itself. Become. Theoretically, if each resistance element R is arranged as shown in Figure 2, and each resistance element has the same resistance value, all has the same temperature characteristics, and all resistance changes due to strain are equal, Specifically, each of the axial components detected in this way is obtained as a completely independent detection value, and no interference occurs. However, when actually forming each resistance element, such ideal conditions cannot be obtained, and thus interference occurs between each detected value. The state of this interference can be actually measured. That is, a force of known magnitude (
Or, by applying acceleration or magnetism) in a predetermined direction,
The detected value (reading of each voltmeter) obtained at that time is actually measured. As a result, it is known that the following characteristic matrix is obtained.

Here, VX, Vy, 'VZ are the voltmeters 61.
62.63, and Ax, Ay, and Az are the component values in each direction of the actually applied force (or acceleration or magnetism). Moreover, PIL-P33 is a coefficient that constitutes a characteristic matrix. This determinant now has a coefficient Kll~ of 3
The matrix using 3 is the inverse matrix of the matrix using coefficients Pa1-P33. If we write this determinant as a general formula, Ax = K11Vx + 12Vy + 13V
zAy = K21Vx +22Vy +23
VzAz =K31Vx +32Vy +33
It becomes Vz. Therefore, for the voltage values VX, Vy, and Vz obtained by the voltmeters 61 to 63, the coefficient Kll~ is 33.
If the above equation is calculated using , correct detection values Ax, Ay, and Az without interference will be obtained.

The signal processing circuit of the present invention performs this calculation using an analog circuit. FIG. 7 shows a block diagram of this circuit. Here, Vx, Vy.

Vz is an analog voltage obtained by voltmeters 61 to 63, respectively. Block 1 with 11=K33 displayed in the coefficient
01 to 109 are analog multipliers that multiply the respective coefficient values, and blocks 111 to 11 indicated by "10" symbols
3 is an analog adder.

If a circuit with such a configuration is used, the correct detection value Ax,
Ay and Az are obtained as output voltages of adders 111 to 113. This can be easily understood since this circuit corresponds to the above-mentioned arithmetic expression.

The above is a circuit for a three-dimensional detection device, but for a two-dimensional detection device, it is only necessary to perform the calculation 12Vy for Ax −KllVx + AV = 22Vy for K21Vx +, so the block diagram in FIG. 8 is used. The circuit shown in can be used. Blocks 201-2
04 is an analog arithmetic unit that multiplies the respective coefficient values, and correct detected values Ax and Ay are obtained as the output voltages of the adders 211 and 212.

Note that a three-dimensional detection device uses nine coefficients and a two-dimensional detection device uses four coefficients, but if the coefficient value is zero, a multiplier for this is not necessary.

Next, specific examples of circuit configurations of the multipliers and adders shown in the block diagrams of FIGS. 7 and 8 will be explained.

FIG. 9 is a circuit diagram showing an example of the configuration of a multiplier. When voltage Vin is applied to the input end of operational amplifier OPI, voltage V out is obtained at the output side.

Here, if we set R3-R1//R2 (// indicates the resistance value when two resistors are connected in parallel), Vout
= −(R2/R1) ・Vin. Therefore, it functions as a multiplier that multiplies the coefficient -(R2/R1). On the other hand, FIG. 10 is a circuit diagram showing an example of the configuration of an adder. All resistors R may have the same resistance value.

The voltages Vinl and Vin are applied to the input side of the operational amplifier OP2.
2. When Vin3 is given, the voltage V Out on the output side
is obtained. Here, Vout −(Vinl +V1n2 +Vin3)
・It becomes 2/3. Therefore, input voltages can be added. FIG. 11 shows a circuit that functions as both a multiplier and an adder. When voltages V1nl, Vin2, and Vin3 are applied to the input terminal of the operational amplifier OP3, a voltage V out is obtained at the output side. Here, Vo
ut --((R4/R1) ・Vinl+ (R4/
R2) ・Vin2 + (R4/R?l) ・Vin3). In other words, this circuit functions as both a multiplier and an adder.

Figure 12 shows Ax - (KIIVX 12Vy + 18Vz) using the multiplier shown in Figure 9 and the adder shown in Figure 10.
- It is a diagram showing a specific circuit that performs the calculation 273. Here, an example of a circuit configuration in the case where Kll>01, 12<O, and 13>0 is shown. The voltages VX, Vy, and Vz are
The voltages appearing on the voltmeters 61 to 63 in Fig. 3 are applied as they are to the operational amplifiers OP4゜OF5.0
By P6, =K11 times, =K12 times, =K respectively
It is amplified 13 times. For that purpose, Rl&-R11/
/R12, R23-R22/R2L, R33-R31/
/R82, and further, l Kll I -R12/R1
1, K12 + -R22/R2L, l KlB
Each resistance value may be set so as to be 1-R32/R31. Note that this amplification operation causes the sign to be inverted.

For Vy, since K12<O, the sign may remain inverted, but for Vx and Vz, KIL>0
, KlB>0, so it is necessary to invert the sign again to restore the original sign. Therefore, this sign inversion is performed by operational amplifiers OP7 and OF2. here,
R14-R15-2・RlB, R34-R35-2・R
3B, the operational amplifiers OP7 and OF2 have an amplification factor of 1 and function simply to invert the sign.

Thus, K11Vx 5 to 12Vy, K13Vz
, and voltages corresponding to these values are applied to the operational amplifier OP9. Here, R4L-R42-R
43-R44-R45, operational amplifier op9
functions as an adder, Vout = (18Vz to KlIVx + 13V to KlIVx +
z) @ 2/3rd (outputted. This output voltage V o
ut corresponds to the detected value Ax.

An example of the signal processing circuit for a force detection device according to the present invention has been described above based on FIG. 12, but the present invention can be implemented using various other circuits. The multiplier and adder in the present invention may be any circuit as long as it can perform analog processing of multiplication and addition. Further, there is no need to configure the multiplier and the adder with separate circuit elements. For example, if a circuit as shown in FIG. 11 is used, one operational amplifier OP3 can serve as both a multiplier and an adder, which is advantageous in that the number of parts can be reduced.

However, when using this circuit, consider the signs of the coefficients and set the input voltages Vinl, Vin2, Vin
It is necessary to make sure that 3 has a sign. In any case, performing correction calculations using analog circuits like this reduces costs and completes calculations quickly compared to correction calculations using digital circuits, making it possible to measure instantaneous phenomena. This is advantageous in such cases. In particular, acceleration detection devices are used to detect shocks during collisions, and by applying the present invention, correct measured values can be obtained instantaneously.

As described above, the signal processing circuit according to the present invention is widely applicable to acceleration detecting devices, magnetic detecting devices, etc. that use force detecting devices as a base, and although the acceleration detecting device has been described in the embodiments of the present application, the signal processing circuit according to the present invention It can also be widely applied to force detection devices and magnetic detection devices.

〔Effect of the invention〕

As described above, according to the signal processing circuit for an acceleration detection device of the present invention, the inverse matrix of the characteristic matrix indicating the state of interference occurring between each axial component is obtained in advance, and the correction calculation using this inverse matrix is performed. Since this is carried out using an analog calculation circuit, it becomes possible to instantly obtain accurate measured values that cancel out the influence of interference17 using a low-cost circuit.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an example of an acceleration detection device to which the present invention is applied, and FIG. 2 is a cross-sectional view of the device shown in FIG.
3 is a circuit diagram of a bridge circuit formed by a resistive element in the device shown in FIG. 1, and FIG. 4 is a top sectional view cut along the device shown in FIG. Figure 5 is a stress distribution diagram when Y is applied to the device shown in Figure 1.
FIG. 6 is a stress distribution diagram when an axial force Fy is applied, FIG. 6 is a stress distribution diagram when a biaxial force Fz is applied to the device shown in FIG. A block diagram of a signal processing circuit for an acceleration detection device, FIG. 8 is a block diagram of a signal processing circuit for an acceleration detection device according to the invention of Part 2 of the present application, and FIG. 9 is a specific circuit of a multiplier used in the signal processing circuit of the present application. 10 is a specific circuit diagram of an adder used in the signal processing circuit of the present application, and FIG. 11 is a circuit diagram of a specific circuit that also serves as a multiplier and an adder used in the signal processing circuit of the present application. FIG. 12 is a specific partial circuit diagram of the signal processing circuit for an acceleration detection device according to the invention of Part 1 of the present application. DESCRIPTION OF SYMBOLS 10...Single crystal substrate, 11...Action part, 12...
Flexible part, 13... Fixed part, 20... Pedestal, 30...
- Weight body, 40... Case, 41... Lid, 50...
-External wiring electrode, 51...bonding wire, 5
2... Bonding pad, 53... External wiring electrode, 60... Power supply, 61-63... Voltmeter, 101
~109... Multiplier, 111-113... Adder,
201-204... Multiplier, 211, 212... Adder, OFI-OP9... Operational amplifier. Figure 4 Figure 7 Start 8 Figure 9 Figure 1O Figure 1

Claims (2)

[Claims] (1) A plurality of resistance elements exhibiting a piezoresistance effect in which electrical resistance changes due to mechanical deformation are arranged on a single crystal substrate,
When an external force due to acceleration acts on a predetermined point of action in the XYZ three-dimensional coordinate system, the single crystal substrate is mechanically deformed by this external force, and the X-axis direction component Ax of the external force applied to the point of action is , Y-axis direction component Ay, Z
The axial component Az is converted into voltage values Vx, Vy obtained based on the bridge circuit constituted by the plurality of resistance elements.
, Vz, and between the Ax, Ay, Az and the Vx, Vy, Vz, Ax=K11Vx+K12Vy+K13VzAy=K2.
1Vx+K22Vy+K23VzAz=K31Vx+K
Coefficients K11, K12, K13, K21, K22, K23, K that satisfy the relational expression 32Vy+K33Vz
31, K32, and K33, calculate the value of the term on the right side of the above relational expression using an analog multiplier, add the right side of the above relational expression using an analog adder, and from these calculation results, detect A signal processing circuit for an acceleration detection device, characterized in that it is configured to obtain values Ax, Ay, and Az. (2) A plurality of resistance elements exhibiting a piezoresistance effect in which electrical resistance changes due to mechanical deformation are arranged on a single crystal substrate,
When an external force due to acceleration acts on a predetermined point of action,
This external force causes mechanical deformation in the single crystal substrate, and the X-axis direction component A of the external force acting on the point of application
Signal processing for an acceleration detection device that detects x and a Y-axis direction component Ay orthogonal thereto based on respective bridge voltage values Vx and Vy of two sets of bridge circuits constituted by the plurality of resistive elements. In the circuit, the Ax,
Between Ay and the above Vx and Vy, Ax=K11Vx+K
12Vy Ay=K21Vx+K22Vy Coefficients K11, K12, K2 that satisfy the following relational expression
1, K22 is calculated, the value of the term on the right side of the above relational expression is calculated using an analog multiplier, the right side of the above relational expression is added using an analog adder, and the detected value Ax and A signal processing circuit for an acceleration detection device, characterized in that it is configured to obtain Ay.