JPH087228B2 - Acceleration detection device - Google Patents

Description

The present invention relates to an acceleration detecting device, and more particularly to an acceleration detecting device capable of detecting two-dimensional or three-dimensional acceleration using a resistance element exhibiting a piezoresistive effect. Regarding

[Conventional technology]

Various industrial devices involving movements such as robots need to detect acceleration in a two-dimensional or three-dimensional coordinate system. That is, in the three-dimensional coordinate system represented by the three axes of XYZ, it becomes necessary to independently detect the two-axis or three-axis direction components of acceleration. Conventionally, generally used acceleration detection devices detect stress strain caused by acceleration by converting it into an electric quantity with a strain gauge or the like using a semiconductor or the like. Usually, a strain gauge is often formed in the structure of the cantilever, and acceleration of a specific direction is often detected by the stress strain of the cantilever.

[Problems to be Solved by the Invention]

However, the conventional acceleration detection device has a problem that the structure is complicated and is not suitable for mass production. For example,
In the device using the cantilever structure, three sets of cantilevers must be combined three-dimensionally in order to detect the components in the three axial directions. Therefore, it is not suitable for mass production and the cost becomes high.

Therefore, it is an object of the present invention to provide an acceleration detecting device which has a low manufacturing cost, is suitable for mass production, and has high measurement accuracy.

[Means for solving the problem]

(1) The first invention of the present application is, in an acceleration detecting device, a fixing part fixed to the device body, an action part receiving a force action due to an acceleration applied to the device body, a fixing part and an action part. A single-crystal substrate having a flexible portion connecting between them is prepared, and a plurality of resistance elements exhibiting a piezoresistive effect in which electric resistance is changed by mechanical deformation are provided on the single-crystal substrate. In the area where mechanical deformation occurs due to the displacement between the fixed part and the fixed part, it is arranged so that mechanical deformation in at least two axial directions in the three-dimensional Cartesian coordinate system can be detected, and the change in electrical resistance of each resistance element Based on the above, it is configured so that each axial component of the acceleration applied to the apparatus main body can be detected.

(2) A second invention of the present application is the acceleration detecting device according to the first invention, wherein the central portion of the single crystal substrate is the acting portion, the outer peripheral portion is the fixing portion,
The portion between these is made a flexible portion, a pedestal for supporting the fixed portion is provided, a weight body is arranged in the central space of this pedestal, and this weight body is connected to the action portion to cause acceleration. The force is made to act effectively.

(3) A third invention of the present application is the acceleration detecting device according to the first invention, wherein the central portion of the single crystal substrate is a fixed portion, the outer peripheral portion is a working portion,
The part between these is made a flexible part, a pedestal supporting the fixed part is provided, a weight body is arranged around this pedestal, and the force caused by acceleration is connected by connecting this weight body to the action part. It is designed to work effectively.

(4) A fourth invention of the present application is, in the acceleration detecting device according to the above-mentioned first to third invention, so as to limit displacement in three-dimensional directions of the acting portion or the weight body caused by a force caused by acceleration. A displacement limiting member is further provided at a predetermined distance from the acting portion or the weight body.

[Work]

(1) According to the first invention of the present application, when a force acts on the single crystal substrate based on acceleration, mechanical deformation occurs in the substrate,
The electric resistance of the resistance element formed on the substrate changes. The direction and magnitude of the applied acceleration can be detected by the change in the electric resistance. As described above, in the device of the present invention, the portion that performs the central function of the device is integrated into one single crystal substrate. The fixed portion, the acting portion, and the flexible portion that compose the single crystal substrate can all be formed by processing the wafer that is the base of the substrate, and each resistance element arranged on the substrate is also a common semiconductor. It can be formed by a planar process. Therefore, mass production can be performed by the same process as that of the semiconductor device, and cost reduction can be realized. Moreover, since the measurement is performed using the piezoresistive element, highly accurate measurement results can be obtained.

(2) According to the second invention of the present application, the outer peripheral portion of the single crystal substrate is fixed to the apparatus main body by the pedestal, and the weight body is connected to the central portion of the single crystal substrate. The weight body has a function of effectively exerting a force resulting from the applied acceleration on the central portion of the single crystal substrate. Since the weight body is located in the central space of the pedestal, it is possible to save space in the entire device.

(3) According to the third invention of the present application, the central portion of the single crystal substrate is fixed to the device main body by the pedestal, and the weight body is connected to the outer peripheral portion of the single crystal substrate. The weight body has a function of effectively exerting a force resulting from the applied acceleration on the outer peripheral portion of the single crystal substrate. Since the weight body is located in the space around the pedestal, it is possible to save space in the entire device. Further, since the mass of the weight body is larger than that of the device of the second invention described above, the sensitivity can be efficiently increased.

(4) According to the fourth aspect of the present invention, even if a large acceleration acts on the apparatus main body, the action portion or the weight body is prevented from moving by the displacement limiting member and is displaced beyond a predetermined upper limit value. Never. Therefore, it is possible to avoid the occurrence of unreasonable mechanical deformation of the single crystal substrate, and it is possible to prevent the single crystal substrate from being damaged by the action of large acceleration.

〔Example〕

The present invention will be described below based on illustrated embodiments.
FIG. 1 is a side sectional view of an acceleration detecting device according to an embodiment of the present invention, and FIG. 2 is an upper sectional view of the device taken along the section line AA. The single crystal substrate 10 plays a central role in this detection device. In this embodiment, a silicon single crystal substrate is used. The single crystal substrate 10 is
As shown in FIG. 2, it has a disk shape, and in this specification, the central portion is referred to as the action portion 11, the periphery thereof is referred to as the flexible portion 12, and the outer peripheral portion thereof is referred to as the fixed portion 13. . A tubular groove is formed on the lower surface of the substrate, and the flexible portion 12 is a portion located above the groove. Since the groove is formed, the flexible portion 12 has a thin wall portion and has flexibility. A cylindrical pedestal 20 is connected below the fixed portion 13, and a cylindrical weight body 30 is connected below the acting portion 11. In this embodiment, a glass material is used for the weight body 30. Since the silicon substrate is used as the single crystal substrate 10, it is preferable to use borosilicate glass such as Pyrex having a thermal expansion coefficient close to that of silicon as the weight body 30. pedestal
The lower surface of the case 20 is fixed to the bottom surface of the case 40, and the upper portion of the case 40 is covered with a lid 41.

As shown in FIG. 2, a plurality of resistance elements R (Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4) are provided on the upper surface of the single crystal substrate 10.
Are formed. These resistance elements R are resistance elements having a piezoresistive effect in which electric resistance changes due to mechanical deformation, and are arranged on the upper surface of the flexible portion 12 in a predetermined direction. The external wiring electrode 50 is led out from the inside of the case to the outside so as to pass through the wiring hole on the side surface of the case 40. The inner end of the external wiring electrode 50 is connected by a bonding wire 51 to a bonding pad 52 (not shown in FIG. 1) provided on the fixed portion 13 of the single crystal substrate 10. The bonding pad 52 is connected to the resistance element R by a wiring pattern (not shown). Therefore, the external wiring electrode 50 is connected to an external control device (not shown).
When electrically connected to, the change in the resistance value of the resistance element R can be measured by an external control device.

Now, in FIG. 2, the X axis is in the right direction, the Y axis is in the upward direction, and the Z axis is in the direction perpendicular to the paper surface (the upward direction in the drawing in FIG. 1).
Each axis is taken to define an XYZ three-dimensional coordinate system. In this coordinate system, four resistance elements Rx1 to Rx4 are arranged on the X axis and are used for detecting an acceleration component in the X axis direction, and four resistance elements Ry1 to Ry4 are arranged on the Y axis and in the Y axis direction. Used to detect the acceleration component of the four resistance elements Rz1 to Rz4 are X
It is arranged on an axis parallel to the axis and in the vicinity thereof, and is used for detecting the acceleration component in the Z-axis direction. As described above, each of the resistance elements R is electrically connected to the external control device through the external wiring electrode 50. In this controller,
For each resistance element R, a bridge circuit as shown in FIG. 3 is assembled. That is, for the resistance elements Rx1 to Rx4, a bridge circuit as shown in FIG. 7A is assembled, and for the resistance elements Ry1 to Ry4, a bridge circuit as shown in FIG. For Rz4, a bridge circuit as shown in FIG. A predetermined voltage or current is supplied from the power supply 60 to each bridge circuit, and each bridge voltage is measured by the ammeters 61, 62, 63.

As shown in FIG. 1, the weight body 30 is suspended in the central space of the cylindrical pedestal 20. When acceleration is applied to the case 40, the weight
An external force acts on 30, and the weight body 30 is displaced from the fixed position. Therefore, the acting portion 11 connected to the weight body 30 is also displaced from the fixed position, and the mechanical strain generated by this displacement is absorbed by the mechanical deformation of the flexible portion 12. When the flexible portion 12 is mechanically deformed, the electric resistance of the resistance element R formed thereon changes. As a result, the equilibrium condition of the bridge circuit shown in FIG. 3 is broken and the needles of the voltmeters 61, 62, 63 swing. This is the basic principle of acceleration detection by this device.

Now, when the resistance element R is arranged as shown in FIG.
In the bridge circuit of FIG. 3, the voltmeter 61 can detect the acceleration component in the X-axis direction, the voltmeter 62 can detect the acceleration component in the Y-axis direction, and the voltmeter 63 can detect the acceleration component in the Z-axis direction. The reason for this will be described below. Figure 4 shows
In the apparatus shown in FIG. 1, the force Fx in the X-axis direction is applied to the weight body 30.
FIG. 6 is a schematic diagram showing a stress strain applied to each resistance element R when is applied. The figure (a) shows the stress distribution in the cross section along the resistance elements Rx1 to Rx4, and the figure (b) shows the resistance element.
The stress distribution in the cross section along Ry1 to Ry4 is shown, and FIG. 7C shows the stress distribution in the cross section along the resistance elements Rz1 to Rz4. In the stress distribution, the extending direction is indicated by + and the contracting direction is indicated by −. For example, FIG. 4A shows resistance elements Rx1 to Rx when a force Fx in the X direction acts on the weight body 30.
The stress distribution in the cross section along x4 is shown. Weight body
The force Fx acting on 30 acts as a moment force on the surface of the single crystal substrate 10 and causes mechanical deformation in a contracting direction with respect to the resistance elements Rx1 and Rx3, resulting in resistance elements Rx2 and Rx.
For x4, mechanical deformation occurs in the extending direction. On the other hand, in the resistance elements Ry1 to Ry4, the stress does not change as shown in FIG. 4 (b). This is the resistance element Ry1 ~ R
This is because the arrangement direction (Y-axis direction) of y4 is orthogonal to the direction of force Fx. Regarding the resistance elements Rz1 to Rz4, the same changes as those of the resistance elements Rx1 to Rx4 occur as shown in FIG. 4 (c). Similarly, the stress distribution generated in each resistance element R when a force Fy in the Y-axis direction is applied is shown in FIGS.
The stress distribution generated in each resistance element R when an axial force Fz is applied is shown in FIGS. 6 (a) to 6 (c). Here, if a resistance element having a property that the resistance value increases with respect to the mechanical deformation in the extending direction and the resistance value decreases with respect to the mechanical deformation in the contracting direction, it acts on the weight body 30. Force Fx, Fy, Fz
The relationship between the resistance value of each resistance element R and the change of the resistance value is as shown in Table 1 below. Here, the sign + indicates an increase in the resistance value, the sign − indicates a decrease in the resistance value, and 0 indicates that the resistance value does not change.

Referring to Table 1 and the bridge circuit of FIG. 3,
The voltmeter 61 detects the force Fx and the voltmeter 62 detects the force.
It can be seen that Fy is detected and the force Fz is detected by the voltmeter 63. For example, if force Fx acts, the third
In the bridge circuit of FIG. 10A, the resistance values on one opposite side both increase and the resistance values on the other opposite side both decrease,
The needle of the voltmeter 61 will swing. However, in the bridge circuit of FIG. 3 (b), the needle of the voltmeter 62 does not swing because there is no change in any resistance value, and in the bridge circuit of FIG. 3 (c), the resistance of each opposite side is reduced. One increases the resistance value and the other decreases the resistance value, which eventually offset each other, and the needle of the voltmeter 63 cannot be swung. In this way, each direction component of the acceleration acting on the main body of the apparatus is detected as the deflection of the needle of the voltmeter 61-63.

In this embodiment, the three-dimensional acceleration detecting device for detecting the acceleration direction components of all three axes of XYZ has been described, but the two-dimensional acceleration detection for detecting the acceleration direction components of two axes of XY, YZ or XZ. The device can be similarly configured. In this case, the resistance element and the bridge circuit may be prepared only for two axes.

The above is the basic operation principle of the acceleration detecting device shown in FIG. Next, a more preferred embodiment will be shown when this device is put to practical use. In the apparatus shown in FIG. 1, as described above, the weight body 30 is suspended in the lower portion of the working portion 11. In this state, if a large acceleration acts, the weight
30 produces a large displacement according to the magnitude of the applied acceleration. However, since the flexible portion 12 is a silicon single crystal substrate, its flexibility is also limited. Therefore, if a large displacement occurs, it cannot be absorbed,
The single crystal substrate 10 is damaged by causing cracks.

FIG. 7 is a side sectional view showing another embodiment in which a device for preventing such damage of the single crystal substrate 10 is elaborated. In this embodiment, the strain element 1 is formed on the lower surface of the silicon single crystal substrate 10A.
The flexure element 10B is fixed to the lower surface of 0A. The flexure element 10B is composed of a central action portion 11B, a flexible portion 12B around the action portion 11B, and a fixed portion 13B that is an outer peripheral portion around the action portion 11B. The flexible portion 12B is thinner than other portions and has flexibility. In the device of this embodiment, the two members, that is, the single crystal substrate 10A and the strain element 10B, fulfill the same function as the single crystal substrate 10 of the device shown in FIG. As the strain generating body 10B, a metal having a thermal expansion coefficient close to that of a silicon single crystal substrate, for example, Kovar (iron, cobalt,
It is preferable to use a nickel alloy). A weight 31 is connected to the lower surface of the action portion 11B, and a cylindrical pedestal 21 is connected to the lower surface of the fixed portion 13B. A bottom plate 42 is further connected to the lower surface of the pedestal 21. FIG. 8 is a top view of this device. On the upper surface of the single crystal substrate 10A, the resistance element R
Is formed, and the bonding pad 52 and the external wiring electrode 53 are connected by the bonding wire 51. The feature of this device is that the single crystal substrate 10A is not directly connected to the weight body 31. Since the flexure element 10B is interposed between the two, the force from the weight body 31 causes the single crystal substrate 10A to move.
Not directly transmitted to. Therefore, even if a large acceleration acts, it is possible to prevent the single crystal substrate 10A from being damaged. Another feature of this device is the shape of the weight body 31 and the pedestal 21. The weight body 31 has an inverted T-shaped cross section, and the pedestal 21 has a shape that encloses the weight body 31 while keeping a constant space therebetween. Even if a large acceleration is applied to this device and a force that moves the weight body 31 to the upper side in the figure acts, the upper peripheral surface 31a of the weight body 31 does not move to the base 2
Since the weight body 31 collides with the lower peripheral surface 21a, the upward displacement of the weight body 31 is limited within a predetermined limit. Further, even if a force that moves the weight body 31 in the left-right direction in the drawing acts, the outer surface 31b of the weight body collides with the inner side surface 21b of the pedestal 21.
The displacement of 31 to the left and right is limited within the specified limit. Further, even if a force that moves the weight body 31 downward is applied, the lower surface 31c of the weight body 31 collides with the upper surface 42c of the bottom plate 42, so that the weight body 31 is not displaced downward. Limited to within the prescribed limits. After all, the displacement of the weight body 31 in the three-dimensional direction is limited within a predetermined limit, and it is possible to prevent the single crystal substrate 10A from being subjected to mechanical deformation exceeding the allowable limit, and when a large acceleration is applied, The crystal substrate 10A can be protected from damage.

FIG. 9 is a side sectional view of an acceleration detecting device according to another embodiment of the present invention. The components of this device are similar to those of the device of FIG. The single crystal substrate 10 has an action part 11,
It is composed of a flexible portion 12 and a fixed portion 13, and has a resistance element R on the upper surface.
(Not shown) is formed. A cylindrical weight body 32 is connected to the lower surface of the action portion 11, and a cylindrical pedestal 22 is connected to the lower surface of the fixed portion 13. The pedestal 22 is fixed to the bottom surface of the case 43. Further, on the upper surface of the single crystal substrate 10, a lid member 44 having a disk-shaped hollow portion at the center of the lower surface is attached. Even in the acceleration detecting device having such a structure,
It is possible to control the displacement of the weight body 32 in the three-dimensional direction.
That is, a large acceleration is applied to this device, and the weight 32
Even if a force is applied to move the upper part of the drawing to the upper side of the figure, the upper surface of the acting portion 11 of the single crystal substrate 10 will be
Since it collides with a, the upward displacement of the weight body 32 is limited within a predetermined limit. In addition, even if a force that moves the weight body 32 in the left-right direction acts, the outer surface 32 of the weight body 32
Since a collides with the inner surface 22a of the pedestal 22, the lateral displacement of the weight body 32 is limited within a predetermined limit. Furthermore, the weight body
Even if a force to move the weight 32 downward is applied, the lower surface 32b of the weight body 32 collides with the bottom surface 43b of the case 43, so that the weight body 32 cannot be displaced downward within a predetermined limit. Limited.
Eventually, the displacement of the weight body 32 in the three-dimensional direction is limited within a predetermined limit, it is possible to prevent the single crystal substrate 10 from being subjected to a mechanical deformation exceeding the allowable limit, and when a large acceleration is applied, The crystal substrate 10 can be protected from damage.

FIG. 10 is a side sectional view of an acceleration detecting device according to still another embodiment of the present invention. The components of this device are also almost the same as the device of FIG. The single crystal substrate 10 has an action part 11,
It is composed of a flexible portion 12 and a fixed portion 13, and has a resistance element R on the upper surface.
(Not shown) is formed. A stepped columnar weight body 33 is connected to the lower surface of the action portion 11, and a stepped cylindrical pedestal 23 is connected to the lower surface of the fixed portion 13. Pedestal 23 is case 45
Fixed to the bottom of the. Even if a large acceleration is applied to this device and a force that moves the weight body 33 upward in the figure acts, the upper peripheral surface 33a of the weight body 33 collides with the lower peripheral surface 23a of the pedestal 23. The upward displacement of the weight body 33 is limited within a predetermined limit. In addition, even if a force that moves the weight body 33 in the left-right direction in the drawing acts, the outer surface 33b of the weight body 33 does not move to the pedestal 2.
Since the weight body 33 collides with the inner side surface 23b, the lateral displacement of the weight body 33 is limited within a predetermined limit. Further, even if a force that moves the weight body 33 downward is applied, the lower surface 33c of the weight body 33 collides with the bottom surface 45c of the case 45, so that the weight body 33 is not displaced downward. Limited to within the prescribed limits.

FIG. 11 is a side sectional view of an acceleration detecting device according to another embodiment of the present invention. This device has an inverted relationship between the inside and outside of the devices described so far. That is, the outer peripheral portion of the single crystal substrate 10 is the acting portion 11, the inner portion thereof is the flexible portion 12, and the central portion thereof is the fixing portion 13. A cylindrical pedestal 70 is connected to the lower surface of the fixed portion 13, and the pedestal 70 is fixed to the bottom surface of the case 46. A cylindrical weight body 80 is connected to the lower surface of the action portion 11. When acceleration is applied, the cylindrical weight body 80 is displaced, and this displacement is transmitted to the single crystal substrate 10. The displacement of the weight body 80 in the left-right direction in the drawing can be limited by the gap formed between the weight body 80 and the pedestal 70. That is, even if a force that moves the weight body 80 in the left-right direction acts, the inner side surface 80a of the weight body 80 collides with the outer side surface 70a of the pedestal 70, so that the weight body 80 moves to the left and right. Will be limited to within a predetermined limit.

The examples described above are examples in which a cylindrical weight body and a cylindrical pedestal are used for a disk-shaped single crystal substrate, but the present invention is limited to those using a circular member. is not. For example, a square single crystal substrate may be used, and a rectangular parallelepiped weight body and a pedestal surrounding the weight body from four sides may be used.

Finally, an example of a method of forming the resistance element R used in the present invention on the single crystal substrate 10 will be described. In this example,
A silicon substrate is used as the single crystal substrate 10, and the resistance element R is formed on this silicon substrate by a semiconductor planar process. First, as shown in FIG. 12 (a),
The N type silicon substrate 101 is thermally oxidized to form a silicon oxide layer 102 on the surface. Then, as shown in FIG. 2B, the silicon oxide layer 102 is etched by a photo-etching method to form an opening 103. Subsequently, as shown in FIG. 3C, boron is thermally diffused from the opening 103 to form a P-type diffusion region 104. Note that the silicon oxide layer 105 is formed in the opening 103 in this thermal diffusion step. Next, as shown in FIG. 3D, silicon nitride is deposited by the CVD method to form the silicon nitride layer 106.
Is formed as a protective layer. Then, as shown in FIG. 7E, the silicon nitride layer 106 and the silicon oxide layer 105 are formed.
After opening the contact hole by photolithography,
As shown in FIG. 6F, the aluminum wiring layer 107 is formed by vapor deposition. And finally, this aluminum wiring layer 10
7 is patterned by photolithography to obtain a structure as shown in FIG. The above steps are shown as an example, and the present invention can be realized by using any resistive element having a piezoresistive effect.

〔The invention's effect〕

(1) According to the first invention of the present application, an acceleration detecting device is provided so that a force is applied to a single crystal substrate based on acceleration and the force is detected as a change in electrical resistance of a resistance element formed on the substrate. Since it is configured, mass production can be performed by the same steps as those for semiconductor devices, cost reduction can be realized, and highly accurate measurement results can be obtained.

(2) According to the second invention of the present application, since the outer peripheral portion of the single crystal substrate is fixed to the apparatus main body by the pedestal and the weight body is provided in the central space of the pedestal, the force due to the applied acceleration is applied. Can be effectively applied to the central portion of the single crystal substrate, and moreover, the space can be saved in the entire device.

(3) According to the third invention of the present application, since the central portion of the single crystal substrate is fixed to the apparatus main body by the pedestal and the weight body is provided around the pedestal, the force caused by the applied acceleration is reduced. It is possible to effectively act on the outer peripheral portion of the crystal substrate, and moreover, it is possible to save space in the entire device. Further, since the mass of the weight body is larger than that of the device of the second invention described above, the sensitivity can be efficiently increased.

(4) According to the fourth aspect of the present invention, since the displacement limiting member for limiting the movement of the acting portion or the weight body is provided, even if a large acceleration acts on the apparatus main body, it is impossible to machine the single crystal substrate. It is possible to avoid mechanical deformation and prevent damage to the single crystal substrate due to the action of large acceleration.

[Brief description of drawings]

1 is a side sectional view of an acceleration detecting apparatus according to an embodiment of the present invention, FIG. 2 is an upper sectional view of the apparatus shown in FIG. 1 taken along the section line AA, and FIG. FIG. 4 is a circuit diagram of a bridge circuit formed by resistance elements in the device shown in FIG.
The figure shows a stress distribution diagram when a force Fx in the X-axis direction acts on the device shown in FIG. 1, and FIG. 5 shows a stress distribution diagram when a force Fy in the Y-axis direction acts on the device shown in FIG. FIG. 6 is a stress distribution diagram when a force Fz in the Z-axis direction acts on the device shown in FIG.
7 is a side sectional view of an acceleration detecting device according to another embodiment of the present invention, FIG. 8 is a top view of the device shown in FIG. 7, and FIG.
FIG. 11 is a side sectional view of an acceleration detecting device according to still another embodiment of the present invention, and FIG. 12 is a process drawing showing an example of a method of forming a resistance element used in the acceleration detecting device of the present invention. 10,10A …… single crystal substrate, 10B …… strain element, 11,11B …… acting part, 12,12B …… flexible part, 13,13B …… fixing part, 20-23…
… Pedestal, 30-33 …… Weight, 40 …… Case, 41 …… Lid,
42 …… bottom plate, 43 …… case, 44 …… cover member, 45,46 ……
Case, 50 ... External wiring electrode, 51 ... Bonding wire, 52 ... Bonding pad, 53 ... External wiring electrode, 60 ... Power supply, 61-63 ... Voltmeter, 70 ... Pedestal, 80 ...
… Weight, 101 …… Silicon substrate, 102 …… Silicon oxide layer, 103 …… Opening, 104 …… P-type diffusion region, 105 …… Silicon oxide layer, 106 …… Silicon nitride layer, 107 …… Aluminum Wiring layer.

Claims (8)

[Claims] 1. An acceleration detecting device for detecting an acceleration acting in the X-axis direction and the Y-axis direction in an XYZ three-dimensional coordinate system, comprising a semiconductor single crystal substrate, a case accommodating the substrate, and a case in the case. A pedestal for supporting and fixing the substrate, a weight body fixed to a part of the substrate, eight resistance elements formed on the substrate, and a detection circuit connected to the eight resistance elements. , And one of the central portion and the peripheral portion of the substrate is defined as a working portion, the other is defined as a fixed portion, and a flexible portion is defined in a region between the working portion and the fixed portion. sometimes,
The flexible portion has a structure having flexibility by making it thinner than the thickness of the acting portion and the fixing portion, and the pedestal connects the fixing portion and the case to each other to support the substrate. It has a function of supporting, the weight body is fixed to the acting portion, the eight resistance elements are arranged in the flexible portion, and the electric resistance is changed by mechanical deformation of the flexible portion. An element showing a piezoresistive effect, which has an origin O at the center position of the substrate, and has an XYZ three-dimensional coordinate system defined so that the XY plane is parallel to the main surface of the substrate. 4 resistance elements Rx1, Rx2, Rx3, Rx4
Are arranged in this order, and four resistance elements Ry1, Ry2, and
Ry3 and Ry4 are arranged in this order, and of the four resistance elements arranged on each coordinate axis, two are in the positive region of each coordinate axis, and the other two are the negative elements of each coordinate axis. The detection circuits are arranged in the respective regions, and the detection circuit acts in the X-axis direction by the equilibrium state of the bridge circuit in which the resistance elements Rx1 and Rx3 are the first opposite sides and the resistance elements Rx2 and Rx4 are the second opposite sides. A function of detecting acceleration, and a function of detecting acceleration acting in the Y-axis direction by the equilibrium state of a bridge circuit in which the resistance elements Ry1 and Ry3 are the first opposite sides and the resistance elements Ry2 and Ry4 are the second opposite sides, An acceleration detecting device comprising: 2. An acceleration detecting device for detecting acceleration acting in the X-axis direction and the Z-axis direction in an XYZ three-dimensional coordinate system, comprising a semiconductor single crystal substrate, a case accommodating the substrate, and a case in the case. A pedestal for supporting and fixing the substrate, a weight body fixed to a part of the substrate, eight resistance elements formed on the substrate, and a detection circuit connected to the eight resistance elements. , And one of the central portion and the peripheral portion of the substrate is defined as a working portion, the other is defined as a fixed portion, and a flexible portion is defined in a region between the working portion and the fixed portion. sometimes,
The flexible portion has a structure having flexibility by making it thinner than the thickness of the acting portion and the fixing portion, and the pedestal connects the fixing portion and the case to each other to support the substrate. It has a function of supporting, the weight body is fixed to the acting portion, the eight resistance elements are arranged in the flexible portion, and the electric resistance is changed by mechanical deformation of the flexible portion. An element showing a piezoresistive effect, which has an origin O at the center position of the substrate, and has an XYZ three-dimensional coordinate system defined so that the XY plane is parallel to the main surface of the substrate. 4 resistance elements Rx1, Rx2, Rx3, Rx4
Are arranged in this order, and four resistance elements Rz1, Rz2, Rz3, Rz4 are arranged in this order on one coordinate axis on the XY plane, and four resistance elements arranged on each coordinate axis are arranged. Of these, two are arranged in the positive area of each coordinate axis and the other two are arranged in the negative area of each coordinate axis. The detection circuit includes the resistance elements Rx1 and Rx3 as the first opposite side and the resistance element. Rx2, Rx4 is the second opposite side, the function to detect the acceleration acting in the X-axis direction by the equilibrium state of the bridge circuit, the resistance elements Rz1, Rz4 are the first opposite side, and the resistance elements Rz2, Rz3 are the second side. An acceleration detecting device having a function of detecting acceleration acting in the Z-axis direction depending on the equilibrium state of a bridge circuit on the opposite side. 3. An acceleration detecting device for detecting acceleration acting in X-axis direction, Y-axis direction and Z-axis direction in an XYZ three-dimensional coordinate system, comprising a semiconductor single crystal substrate and a case for accommodating the substrate. A pedestal for supporting and fixing the substrate in this case, a weight body fixed to a part of the substrate, 12 resistance elements formed on the substrate, and connected to the 12 resistance elements. And a detection circuit, wherein one of the central portion and the peripheral portion of the substrate is defined as an acting portion and the other is defined as a fixed portion, and the flexible portion is provided in a region between the acting portion and the fixed portion. When you define the division,
The flexible portion has a structure having flexibility by making it thinner than the thickness of the acting portion and the fixing portion, and the pedestal connects the fixing portion and the case to each other to support the substrate. It has a function of supporting, the weight body is fixed to the acting portion, the 12 resistance elements are arranged in the flexible portion, and the electrical resistance is changed by mechanical deformation of the flexible portion. An element showing a piezoresistive effect, which has an origin O at the center position of the substrate, and has an XYZ three-dimensional coordinate system defined so that the XY plane is parallel to the main surface of the substrate. 4 resistance elements Rx1, Rx2, Rx3, Rx4
Are arranged in this order, and four resistance elements Ry1, Ry2, and
Ry3, Ry4 are arranged in this order, and four resistance elements Rz1, Rz2, Rz3, Rz4 are arranged in this order on one coordinate axis on the XY plane, and four resistance elements are arranged on each coordinate axis. Of the resistance elements, two are arranged in the positive area of each coordinate axis, and the other two are arranged in the negative area of each coordinate axis. In the detection circuit, the resistance elements Rx1 and Rx3 are arranged on the first opposite side. , The resistance element Rx2, Rx4 is the second opposite side, the function of detecting the acceleration acting in the X-axis direction by the equilibrium state of the bridge circuit, the resistance element Ry1, Ry3 is the first opposite side, the resistance element Ry2, Ry4 is The second opposite side, the function of detecting the acceleration acting in the Y-axis direction depending on the equilibrium state of the bridge circuit, and the resistance element Rz1,
An acceleration detecting device having a function of detecting acceleration acting in the Z-axis direction according to a balanced state of a bridge circuit having Rz4 as a first opposite side and resistance elements Rz2 and Rz3 as a second opposite side. 4. The detection device according to claim 1, wherein a pedestal is connected to the lower surface of the fixed portion of the substrate, a weight body is connected to the lower surface of the operating portion of the substrate, and an upper surface of the substrate is An acceleration detecting device, comprising a lid member connected to limit the displacement of the acting portion in the Z-axis direction within a predetermined range. 5. The detection device according to claim 1, wherein the central portion of the substrate serves as a working portion and the peripheral portion serves as a fixed portion, a pedestal is connected to the lower surface of the fixed portion, and the lower surface of the working portion is overlapped. The weight is connected so that the pedestal surrounds the circumference of the weight body, and the outer surface of the weight body and the inner surface of the pedestal maintain a predetermined distance when acceleration is not applied. An acceleration detecting device characterized in that it functions as a member for limiting the displacement of the weight body in the X-axis direction or the Y-axis direction within a predetermined range. 6. The detection device according to claim 5, wherein a lower surface of the weight body and a facing surface of the case maintain a predetermined distance in a state where no acceleration is applied, and the case is the weight body. An acceleration detecting device characterized in that the acceleration detecting device functions as a member for limiting the displacement of the z in the Z-axis direction within a predetermined range. 7. The detection device according to claim 1, wherein a central portion of the substrate serves as a fixed portion and a peripheral portion serves as a working portion, a pedestal is connected to a lower surface of the fixed portion, and a lower surface of the working portion is overlapped. An acceleration detecting device having a structure in which a weight is connected and the weight surrounds the periphery of the pedestal. 8. The acceleration detecting device according to claim 1, wherein a silicon single crystal substrate is used as the substrate, and the weight body is made of glass.