JPH04337431A - Detector for power, acceleration, magnetism relating to three-dimensional direction - Google Patents

Abstract

PURPOSE:To equalize detection sensitivity of X, Y, Z-axes directional components in an acceleration detector relating to three-dimensional direction, using a capacity device. CONSTITUTION:A fixed substrate 10 is fixed to a device box 40, and the periphery of a flexible substrate 20 is fixed to the device box 40. When acceleration works on a work 30, deformation is generated on the flexible substrate. Displacement is generated on a displacement substrate 81 as a result through a connection member 70. Capacity devices C1, C3, C5 are formed by fixed electrodes 11, 13, 15 formed on the under surface of the fixed substrate 10, as well as displacement electrodes 21, 23, 25 formed on the upper surface of the displacement substrate 81 in an opposed manner to the fixed electrodes. The acceleration in X-axis direction is detected by variation in the capacity values of the capacity devices C1, C3, while the acceleration in Z-axis direction is detected by the variation in the capacity value of the capacity device C5. The periphery of the displacement substrate 81 is tilted, while inter-electrode distance of C1 and C3, and inter-electrode distance of C5 are changed, and the detection sensitivity in each axial direction is thus adjusted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force/acceleration/magnetism detection device, and more particularly to a detection device capable of obtaining detected values for each three-dimensional component.

0002

2. Description of the Related Art In the automobile industry, machinery industry, etc., there is an increasing demand for detection devices that can accurately detect physical quantities such as force, acceleration, and magnetism. In particular, a compact device that can detect these physical quantities for each three-dimensional component is desired.

In order to meet these demands, a gauge resistor is formed on a semiconductor substrate such as silicon, and the mechanical strain that occurs in the substrate due to an external force is converted into an electrical signal using the piezoresistive effect. Force, acceleration, and magnetism detection devices have been proposed. However, a detection device using such a gauge resistor has problems in that it is expensive to manufacture and requires temperature compensation. Therefore, the patent application No. 2-27
No. 4,299 proposes a novel detection device that utilizes changes in capacitance. In this new detection device, a capacitive element is composed of a fixed electrode formed on a fixed substrate and a displacement electrode that generates displacement due to the action of force. Each of the three-dimensional components of the applied force can be detected. In addition, Japanese Patent Application No. 2-416188 discloses a manufacturing method for this new detection device, and PCT/JP91/00428, an international application based on the Patent Cooperation Treaty, discloses the following:
A method of testing this novel detection device is disclosed.

0004

[Problems to be Solved by the Invention] However, the above-mentioned novel force/acceleration/magnetism detection device that utilizes changes in capacitance has the problem of variations in detection sensitivity in each three-dimensional axis direction. be. More specifically, a three-dimensional coordinate system with an XY plane parallel to the substrate surfaces of the fixed substrate and the displacement substrate is defined, and the fixed electrode formed on the fixed substrate, the displacement electrode formed on the displacement substrate, and the When detecting the X, Y, and Z axis components of the applied force based on changes in the capacitance of the capacitive element configured by , the detection sensitivity in the X-axis direction and the detection sensitivity in the Y-axis direction are the same, but There is a difference between these and the detection sensitivity in the Z-axis direction. When a difference in detection sensitivity occurs in this way, it is necessary to perform sensitivity correction on the detection value of each axial component extracted as an electrical signal. Therefore, a disadvantage arises in that the electric circuit that processes the detection signal becomes complicated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a three-dimensional force/acceleration/magnetism detection device in which the detection sensitivity in each three-dimensional axis direction is adjusted to a desired value.

[0006]

[Means for Solving the Problems] (1) The first invention of the present application provides a device for detecting axial components of force in an XYZ three-dimensional coordinate system, in which a fixed substrate having a fixed surface extending approximately along an XY plane is used. and a displacement substrate having a displacement surface facing the fixed surface and extending approximately along the XY plane, a fixed electrode formed on the fixed surface, and a displacement electrode formed on the displacement surface. At least three pairs of electrodes are configured to face each other, and when a force in the X-axis direction is applied to a predetermined point of action that can displace the displacement substrate, the first electrode pair of the three pairs of electrodes is The structure is configured so that the applied force in the X-axis direction can be detected based on the change in the distance between the electrodes, and when the force in the Y-axis direction is applied to the point of action, the second of the three electrode pairs The structure is configured so that the applied force in the Y-axis direction can be detected based on the change in the distance between the electrode pairs, and when the force in the Z-axis direction is applied to the point of application, the force in the Z-axis direction The structure is configured such that the applied force in the Z-axis direction can be detected based on a change in the inter-electrode distance for the third electrode pair, and the average inter-electrode distance for the third electrode pair is calculated based on the change in the inter-electrode distance for the third electrode pair. Alternatively, the distance between the electrodes may be different from the average inter-electrode distance in the second electrode pair.

(2) The second invention of the present application is the detection device according to the first invention, which includes a fixed part fixed to the device housing, an action part to which external force is transmitted, and a fixed part. and a flexible part formed between the action part and the action part;
and an effecting body that receives an external force and transmits this force to the acting part of the flexible substrate, and is configured to displace the displacement board based on the displacement generated in the acting part. This is what I did.

(3) A third invention of the present application is a detection device according to the above-mentioned first or second invention, in which a surface on which the electrodes forming the first electrode pair and the electrodes forming the second electrode pair are formed. The average inter-electrode distance is made different by making the electrodes inclined with respect to the formation surface of the electrodes constituting the third electrode pair.

(4) A fourth invention of the present application is a detection device according to the first or second invention, in which a surface on which the electrodes forming the first electrode pair and the electrodes forming the second electrode pair are formed. The average inter-electrode distance is made different by providing a step on the surface on which the electrodes constituting the third electrode pair are formed.

(5) A fifth invention of the present application is such that in the detection device according to the first to fourth inventions described above, the displacement substrate is displaced by a force generated due to acceleration, and acceleration can be detected. This is what I did.

(6) The sixth invention of the present application is such that in the detection device according to the first to fourth inventions described above, the displacement substrate is displaced by a force generated due to magnetism to detect magnetism. This is what I did.

0012

[Operation] According to the present invention, the average inter-electrode distance of the electrode pair that detects the force in the X-axis direction and the electrode pair that detects the force in the Y-axis direction, and the average inter-electrode distance of the electrode pair that detects the force in the Z-axis direction. Each electrode is formed so that the distance between the electrodes is different. In this invention, the change Δd in the inter-electrode distance is detected as the change ΔC in capacitance, but if the average inter-electrode distance of the electrode pair differs, the value of ΔC obtained for the same Δd differs. Therefore, sensitivity can be adjusted by adjusting the average inter-electrode distance.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on illustrative embodiments. First, the basic structure and basic principle of a detection device to which the present invention is applied will be briefly described. FIG. 1 is a side sectional view showing the basic structure of an acceleration detection device to which the present invention is applied. The main components of this detection device are a fixed substrate 10, a flexible substrate 20, an effecting body 30,
And there is a device housing 40. FIG. 2 shows a bottom view of the fixed substrate 10. FIG. 1 shows a cross section of the fixed substrate 10 of FIG. 2 taken along the X axis. The fixed substrate 10 is a disk-shaped substrate as shown in the figure, and the periphery thereof is fixed to the device casing 40. On this lower surface, fan-shaped fixed electrodes 11 to 14 are provided.
A disk-shaped fixed electrode 15 is formed as shown in the figure. On the other hand, FIG. 3 shows a top view of the flexible substrate 20. A cross section of the flexible substrate 20 of FIG. 3 taken along the X-axis is shown in FIG. The flexible substrate 20 is also a disk-shaped substrate as shown in the figure, and its periphery is fixed to the device casing 40. On this upper surface, fan-shaped displacement electrodes 21 to 24 and a disc-shaped displacement electrode 25 are formed as shown in the figure. The effecting body 30 is
As shown by the broken line in FIG. 3, the upper surface thereof has a cylindrical shape, and is coaxially joined to the lower surface of the flexible substrate 20. The device housing 40 has a cylindrical shape and firmly supports the fixed substrate 10 and the flexible substrate 20 around the fixed substrate 10 and the flexible substrate 20.

The fixed substrate 10 and the flexible substrate 20 are arranged parallel to each other at a predetermined interval. Both are disk-shaped substrates, but the fixed substrate 10 is highly rigid and does not easily bend, while the flexible substrate 20 is flexible and bends when force is applied. There is. In the example shown in FIG. 1, the rigidity of the fixed substrate 10 is increased by increasing the thickness, and the flexibility is imparted to the flexible substrate 20 by decreasing the thickness. Also, it may be made to have flexibility. Alternatively, flexibility can be imparted by forming grooves or through holes in the substrate. The fixed substrate 10, the flexible substrate 20, and the action body 30 may be made of any material as long as they can perform their original functions. For example, it can be made of semiconductor, glass, etc., or it can be made of metal. However, when the fixed substrate 10 and the flexible substrate 20 are made of metal, it is necessary to take measures such as forming an insulating layer between the electrodes so that the electrodes do not short-circuit. Also,
Each electrode layer may be made of any material as long as it has conductivity. Note that the fixed substrate 10 and the flexible substrate 2
0. When the effecting body 30 is composed of a semiconductor substrate or a glass substrate, it is preferable that the shape thereof is not a disk shape but a rectangular plate shape in order to facilitate assembly.

Now, as shown in FIG. 1, a point of action P is defined at the center of gravity of the effecting body 30, and XY
Define the Z three-dimensional coordinate system as shown in the figure. That is, Figure 1
The X-axis is defined to the right, the Z-axis is upward, and the Y-axis is perpendicular to the paper and toward the back of the paper. The central part of the flexible substrate 20 to which the action body 30 is joined is called an action part, and the peripheral part fixed by the device casing 40 is called a fixed part.
If the part between these parts is called a flexible part, when acceleration acts on the effecting body 30, the flexible part is bent, and the acting part is displaced with respect to the fixed part. Here, if this entire detection device is mounted on, for example, a car, acceleration will be applied to the effecting body 30 based on the running of the car. This acceleration causes an external force to act on the point of application P. When no force is applied to the point of application P, as shown in FIG.
and remain parallel to each other with a predetermined interval. now,
A combination of fixed electrodes 11 to 15 and displacement electrodes 21 to 25 facing each other is a capacitive element C1.
I will call it ~C5. Here, for example, the point of action P
When a force Fx in the X-axis direction is applied to the flexible substrate 20, this force Fx generates a moment force on the flexible substrate 20, causing the flexible substrate 20 to bend as shown in FIG. Due to this bending, the distance between the displacement electrode 21 and the fixed electrode 11 increases, but the distance between the displacement electrode 23 and the fixed electrode 13 decreases. If the force acting on the point of application P is -Fx in the opposite direction, a deflection in the opposite relationship will occur. When the force Fx or -Fx acts in this manner, a change appears in the capacitance of the capacitive elements C1 and C3, and by detecting this, the force Fx or -Fx can be detected. At this time, the displacement electrodes 22, 24,
Although the distance between each of the electrodes 25 and the fixed electrodes 12, 14, and 15 may partially increase or decrease, it may be considered that the distance does not change as a whole. On the other hand, when force Fy or -Fy in the Y direction is applied, the displacement electrode 2
Similar changes occur only in the distance between the displacement electrode 24 and the fixed electrode 12 and the distance between the displacement electrode 24 and the fixed electrode 14. Furthermore, when a force Fz in the Z-axis direction is applied, the distance between the displacement electrode 25 and the fixed electrode 15 becomes smaller, as shown in FIG. growing. At this time, the distance between the displacement electrodes 21 to 24 and the fixed electrodes 11 to 14 also becomes smaller or larger;
The change in the distance between the displacement electrode 25 and the fixed electrode 15 is most remarkable. Therefore, force Fz or -Fz can be detected by detecting a change in the capacitance of this capacitive element C5.

In general, the capacitance C of a capacitive element is expressed as C=εS, where S is the electrode area, d is the electrode spacing, and ε is the dielectric constant.
/d. Therefore, as the distance between the opposing electrodes approaches, the capacitance C increases, and as the distance between the opposing electrodes approaches, the capacitance C decreases. This detection device utilizes this principle to measure the change in capacitance between each electrode, and based on this measurement value, detects the external force acting on the point of action P, or in other words, the applied acceleration. be. That is, acceleration in the X-axis direction is based on the capacitance change between capacitive elements C1 and C3, acceleration in the Y-axis direction is based on the capacitance change in capacitive elements C2 and C4, and acceleration in the Z-axis direction is based on the capacitance change in capacitive element C5. Detection is performed based on each.

Actually, acceleration components in each axis direction are detected by a detection circuit as shown in FIG. That is, the capacitance values of the capacitive elements C1 to C5 are converted into voltage values V1 to V5 by the CV conversion circuits 51 to 55, respectively. Then, the acceleration in the X-axis direction is calculated by the subtracter 61 (V1
−V3) is obtained at the terminal Tx as a differential voltage calculated as (V2−
V4) is obtained at the terminal Ty as a differential voltage after performing the calculation, and the acceleration in the Z-axis direction is obtained as a voltage V5 at the terminal T.
can be obtained by z.

The basic structure and operating principle of this acceleration detecting device have been described above, and a cross section of a more practical structure is shown in FIG. The device shown in FIG. 7 is similar to the basic device described above in that fixed electrodes 11 to 15 are formed on a fixed substrate 10 fixed to a device housing 40, but displacement electrodes 21 to 25 are formed on a fixed substrate 10 fixed to a device housing 40. The formation position is slightly different. That is, the bottom surface of a cylindrical joining member 70 is fixed to the center part (acting part) of the upper surface of the flexible substrate 20, and the center part of a disc-shaped displacement board 80 is fixed to the upper surface of this joining member 70. There is. The displacement electrodes 21 to 25 are formed on the upper surface of this displacement substrate 80. The arrangement of the displacement electrodes 21 to 25 is the same as that shown in FIG. The structure shown in FIG. 7 can be expected to operate with higher sensitivity than the basic structure shown in FIG. That is, in the structure shown in FIG.
The displacement based on the force acting on the flexible substrate 20 is not sufficiently transmitted to the outer peripheral portion (fixed portion) of the flexible substrate 20. This is because this outer circumferential portion is fixed to the device housing 40 and therefore cannot be significantly displaced. Therefore, the displacement electrode 21
No displacement occurs efficiently in the outer circumferential portion of .about.24. On the other hand, according to the structure shown in FIG. 7, the displacement board 80 is only joined at its center to the center (action part) of the flexible board 20 by the joining member 70, and the The displacement is not limited in any way by 40. Therefore, displacement occurs efficiently in the displacement electrodes 21 to 25.

Now, let us touch upon the subject matter of the present invention. In the acceleration detection device with the practical structure shown in FIG. 7, acceleration in the X-axis direction, acceleration in the Y-axis direction, and Z
Let's consider the detection sensitivity for acceleration in the axial direction. Considering that the electrodes are arranged as shown in FIGS. 2 and 3, it will be understood that the detection sensitivity in the X-axis direction and the detection sensitivity in the Y-axis direction are the same. The X-axis and the Y-axis are orthogonal axes within the same plane, and the geometrical conditions regarding detection are exactly the same. That is, the electrode pair 11, 21
The acceleration in the X-axis direction is detected based on the change in capacitance between the electrode pair 12 and 22 and the electrode pair 14 and 24. The acceleration in the Y-axis direction is only detected based on this, and theoretically the detection sensitivities of both are completely equal. On the other hand, acceleration detection in the Z-axis direction is performed using the electrode pair 15,
This is done based on the change in capacitance at 25, and the geometric conditions are different from those for detecting acceleration in the X-axis or Y-axis direction. Therefore, the detection sensitivity in the Z-axis direction is generally lower than the detection sensitivity in the X-axis or Y-axis directions. In this way, if the detection sensitivity varies in each three-dimensional axis direction, a processing circuit for sensitivity correction becomes necessary, which is not preferable. The present invention presents a technique useful for adjusting the detection sensitivity in each axial direction.

FIG. 8 is a side sectional view of an acceleration detection device according to an embodiment of the present invention. When compared with the device shown in FIG. 7, the features of its structure become clear. In the device shown in FIG.
Displacement electrodes 21 to 2 are provided on the upper surface of a flat disk-shaped displacement substrate 80.
In contrast, in the device shown in FIG. 8, a displacement electrode 2 is formed on the upper surface of a dish-shaped displacement substrate 81 with an inclined peripheral surface.
1 to 25 are formed. The displacement electrode 25 is formed on a flat surface at the center, while the displacement electrodes 21 to 24 are formed on inclined surfaces around it. As mentioned above, the electrode 11
-15 and electrodes 21-25 facing each other
When the capacitive elements constituted by and are respectively represented as C1 to C5, in the structure shown in FIG. 7, the average inter-electrode distances of the capacitive elements C1 to C5 are all equal. On the other hand, in the structure shown in FIG. 8, the average inter-electrode distance of capacitive elements C1 to C4 is larger than the average inter-electrode distance of capacitive element C5.

Here, in general, the distance d between the electrodes of the capacitive element
Considering the relationship between C and capacitance value C, a relationship as shown in the graph shown in FIG. 9 is known. According to this relationship, it can be seen that when a displacement of the width Δd occurs around the inter-electrode distance d=d1, a large capacitance value change of ΔC1 is obtained. However, when a displacement of the width Δd occurs around the inter-electrode distance d=d2, only a small capacitance change of ΔC2 is obtained. That is, even when the same displacement Δd is detected as a change in capacitance, the obtained capacitance value change (that is, detection sensitivity) differs depending on the inter-electrode distance d. More specifically, the smaller the inter-electrode distance d, the higher the detection sensitivity. After all, in the structure shown in FIG. 8, by increasing the average distance between the electrodes of the capacitive elements C1 to C4, the detection sensitivity in the X-axis and Y-axis directions can be lowered to match the detection sensitivity in the Z-axis direction. In reality, the sensitivity differs depending on the electrode area, so the area of each electrode and the degree of inclination of the displacement substrate should be comprehensively taken into consideration.
The design will be such that the sensitivity in each of the X, Y, and Z axis directions is equal.

On the other hand, in order to increase the detection sensitivity in the X-axis and Y-axis directions and make the difference with the detection sensitivity in the Z-axis direction noticeable,
A structure as shown in FIG. 10 may be used. Here, a dish-shaped displacement substrate 82 whose periphery is inclined upward is used to reduce the average distance between the electrodes of the capacitive elements C1 to C4. Therefore, the detection sensitivity in the X-axis and Y-axis directions is further improved.

[0023] Instead of providing an inclination to the displacement substrate, the average inter-electrode distance can also be changed by providing a step. The structure shown in FIG. 11 is an example in which a displacement substrate 83 with an upwardly convex central portion is used, and the distance between electrodes of a capacitive element formed in the central portion is reduced to improve detection sensitivity in the Z-axis direction. It is. Furthermore, the structure shown in FIG. 12 uses a displacement substrate 84 with a downwardly convex central portion, and increases the distance between the electrodes of the capacitive element formed in the central portion to reduce the detection sensitivity in the Z-axis direction. This is an example.

The embodiment shown in FIG. 13 is a further improvement of the embodiment shown in FIG. 11 to improve the detection accuracy in the Z-axis direction. The flexible substrate 20 and the displacement substrate 91 are connected by a connecting member 92, and an auxiliary substrate 93 is further provided between them. A through hole is formed in the center of this auxiliary board 93, and the connecting member 92 is inserted into this through hole. Displacement electrodes 21 to 25 formed on the upper surface of the displacement substrate 91 and fixed electrodes 11 to 15 formed on the lower surface of the fixed substrate 10
The capacitive elements C1 to C5 are configured by the above-described embodiments, but in this embodiment, the displacement electrodes 26 formed on the lower surface of the displacement substrate 91 and the auxiliary substrate 9
3 and a fixed electrode 16 formed on the upper surface of the capacitive element C6. In a detection device having such a configuration, a detected value in the Z-axis direction is obtained by a circuit shown in FIG. That is, the capacitance values of the capacitive elements C5 and C6 are converted into voltage values V5 and V6 by the CV conversion circuits 55 and 56, and the difference V5-V6 is obtained by the subtracter 63, and this is used as the detected value in the Z-axis direction. . If the difference is also used for detection in the Z-axis direction in this way, error factors are canceled out and more accurate detection becomes possible. Regarding this reason, please refer to the international application PCT/J based on the Patent Cooperation Treaty.
It is detailed in §4 of specification P91/00428.

Although the present invention has been described above based on a three-dimensional acceleration detecting device, the present invention is not limited to only an acceleration detecting device, but can also be applied to a force detecting device or a magnetic detecting device. be. For example, in the acceleration detection device shown in FIG. 8, if a contactor is attached to the effecting body 30 and the flexible substrate 20 is displaced based on the force acting on the tip of the contactor, it can be used as a three-dimensional force detection device. can be used. Furthermore, if the effecting body 30 is made of a magnetic material, the effecting body 30 will receive magnetic force based on the magnetic field of the space in which the detection device is placed, so it can be used as a magnetic detection device. can.

[0026] In the above embodiment, an example was shown in which the distance between the electrodes is adjusted by tilting the displacement substrate or forming a stepped structure, but it is also possible to tilt the fixed substrate or forming a stepped structure. . Further, the distance between the electrodes may be adjusted by other methods. Furthermore, in the above embodiment, five fixed electrodes and five displacement electrodes are provided, but one electrode may be composed of one common electrode, or a larger number of electrodes may be provided. .

[0027]

Effects of the Invention As described above, according to the present invention, in a force/acceleration/magnetism detection device in three-dimensional directions, an electrode pair for detecting a force in the X-axis direction and an electrode pair for detecting a force in the Y-axis direction can be used. Since each electrode is formed so that the average inter-electrode distance and the average inter-electrode distance of the electrode pair that detects the force in the Z-axis direction have desired values, the detection sensitivity in each three-dimensional axis direction is improved. It is possible to provide a detection device in which the value is adjusted to a desired value.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the basic structure of an acceleration detection device to which the present invention is applied.

2 is a bottom view of the fixed substrate 10 in the detection device shown in FIG. 1. FIG.

3 is a top view of the flexible substrate 20 in the detection device shown in FIG. 1. FIG.

4 is a side sectional view showing a state where a force Fx in the X-axis direction is applied to the detection device shown in FIG. 1; FIG.

5 is a side sectional view showing a state where a force Fz in the Z-axis direction is applied to the detection device shown in FIG. 1. FIG.

6 is a circuit diagram showing a signal processing circuit used in the detection device shown in FIG. 1. FIG.

7 is a side sectional view showing a more practical structure of the detection device shown in FIG. 1. FIG.

FIG. 8 is a side cross-sectional view of an acceleration detection device according to an embodiment of the present invention in which detection sensitivity in the X-axis and Y-axis directions is reduced by using a displacement substrate with an inclined surface.

FIG. 9 is a graph showing the relationship between the distance between electrodes and the capacitance value in a capacitive element.

[Figure 10] Using a displacement substrate with an inclined surface, the X-axis and Y-axis
FIG. 2 is a side sectional view of an acceleration detection device according to an embodiment of the present invention with improved detection sensitivity in the axial direction.

FIG. 11 is a side cross-sectional view of an acceleration detection device according to an embodiment of the present invention in which detection sensitivity in the X-axis and Y-axis directions is reduced by using a displacement substrate with steps.

FIG. 12 is a side sectional view of an acceleration detection device according to an embodiment of the present invention in which detection sensitivity in the X-axis and Y-axis directions is improved using a displacement substrate with steps.

13 is a side cross-sectional view of an acceleration detection device according to an embodiment shown in FIG. 11 with improvements for performing detection in the Z-axis direction with high accuracy; FIG.

14 is a circuit diagram of a signal processing circuit used in the detection device shown in FIG. 13. FIG.

[Explanation of symbols]

10...Fixed board 11-16...Fixed electrode 20...Flexible board 21-26...displacement electrode 30...Action body 40...Device housing 51-56...CV conversion circuit 61-63...Subtractor 70...Joining member 80-84...Displacement board 91...Displacement board 92...Joining member 93...Auxiliary board

Claims (6)

[Claims] 1. A device for detecting each axial component of force in an XYZ three-dimensional coordinate system, comprising: a fixed substrate having a fixed surface extending approximately along the XY plane; a displacement substrate having a displacement surface extending along the fixed electrode formed on the fixed surface;
A displacement electrode formed on the displacement surface is configured with at least three pairs of electrodes facing each other, and when a force in the X-axis direction is applied to a predetermined point of action capable of displacing the displacement substrate, The structure is configured such that the applied force in the X-axis direction can be detected based on the change in the inter-electrode distance for the first electrode pair of the three pairs of electrodes, and the force in the Y-axis direction is applied to the point of application. is configured to be able to detect the applied force in the Y-axis direction based on a change in the inter-electrode distance for the second electrode pair of the three electrode pairs, and at the point of application, When a force in the Z-axis direction is applied, the applied force in the Z-axis direction can be detected based on a change in the distance between the electrodes of the third electrode pair of the three pairs of electrodes, The force detection in a three-dimensional direction is characterized in that the average inter-electrode distance in the third electrode pair is different from the average inter-electrode distance in the first electrode pair or the second electrode pair. Device. 2. The force detection device according to claim 1, wherein: a fixed part fixed to the device housing, an acting part to which external force is transmitted, and a space between the fixed part and the acting part. a flexible substrate having a formed flexible portion having flexibility; and an effecting body that receives an external force and transmits this force to the acting portion of the flexible substrate, 1. A force detection device in a three-dimensional direction, characterized in that the device is configured to displace a displacement substrate based on a displacement occurring in a portion. 3. The force detection device according to claim 1, wherein the forming surfaces of the electrodes forming the first electrode pair and the electrodes forming the second electrode pair form the third electrode pair. A force detection device in a three-dimensional direction, characterized in that the average inter-electrode distance is varied by tilting the electrodes with respect to the surface on which they are formed. 4. The force detection device according to claim 1, wherein the forming surfaces of the electrodes forming the first electrode pair and the electrodes forming the second electrode pair form the third electrode pair. 1. A force detection device in a three-dimensional direction, characterized in that the average distance between the electrodes is varied by providing a step on the surface on which the electrodes are formed. 5. The detection device according to claim 1, wherein the displacement substrate is displaced by a force generated due to acceleration, and acceleration can be detected. Detection device. 6. The detection device according to claim 1, wherein the displacement substrate is displaced by a force generated due to magnetism to detect magnetism. Detection device.