JP2007093615A - Angular velocity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce in mass production manner, small-sized and high-precision multi-axis angular velocity sensors. <P>SOLUTION: Along a Z-axis, a pivot 130 is provided on a substrate 100, of which the upper surface is along an XY plane and a rotor 200 of which the outer side is annular structure is fitted. The rotor 200 is supported by the pivot 130 so as to be freely inclining and freely rotating. By supplying alternating voltage to stators 111 and 115, the rotor 200 rotates while floating. If the angular velocity ωx about X-axis is working to the substrate 100, the part 211 of the substrate 100 moving above the X-axis with a velocity component in the Y-axis positive direction is acted by the Coriolis force Fcz in the Z-axis positive direction and the rotor moves away from the substrate. A capacitative element is formed with fixed electrode pair 141A and 141B on the substrate side and a moving electrode 231. By measuring the capacitance value of the fixed electrode pair 141A and 141B, the size of the Coriolis force Fcz can be detected which is output as the angular velocity ωx. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an angular velocity sensor, and more particularly, to an angular velocity sensor suitable for mass production using micromachining technology and semiconductor technology.

  In the automobile industry and the machine industry, there is an increasing demand for sensors that can accurately detect the acceleration and angular velocity of a moving object. Various types of acceleration sensors have been proposed in the past, and small sensors capable of accurately detecting the applied acceleration in two or three dimensions have been put into practical use. For example, Patent Document 1 below discloses an acceleration sensor that uses a change in resistance value of a piezoresistive element formed on a semiconductor substrate. Also, the following Patent Document 2 discloses an acceleration sensor that uses a capacitance element or a piezoelectric element to detect applied acceleration for each coordinate axis direction. A multi-axis acceleration sensor using a type of piezoelectric element is disclosed.

  On the other hand, there are relatively few references on angular velocity sensors. In particular, almost no literature on angular velocity sensors that can simultaneously detect angular velocities around multiple axes can be found. Normally, the angular velocity sensor is used to detect an angular velocity such as a power axis of a vehicle, and has only a function of detecting an angular velocity around a specific one axis. When obtaining the rotational speed of such a power shaft, it is sufficient to use a one-dimensional angular velocity sensor. However, as a sensor for detecting the angular velocity of an object that freely moves in a three-dimensional space, a two-axis Alternatively, a multi-axis angular velocity sensor that can simultaneously detect angular velocities around three axes is desired.

In order to meet such demand, the inventor of the present application has proposed a novel multi-axis angular velocity sensor in Patent Document 4 below. This new angular velocity sensor generates Coriolis force in the direction of the third coordinate axis when an angular velocity acts around the second coordinate axis on an object moving in the direction of the first coordinate axis in the XYZ three-dimensional orthogonal coordinate system. In this method, the applied angular velocity is indirectly detected by detecting the generated Coriolis force. For the detection of Coriolis force, techniques cultivated by conventional acceleration sensors are applied, and piezoresistive elements, capacitive elements, piezoelectric elements, and the like are used.
International Publication No. WO88 / 08522 International Publication No. WO92 / 17759 International Publication No. WO93 / 02342 International Publication No. WO94 / 23272

  An object of the present invention is to provide a more specific and practical mechanism of an angular velocity sensor based on the above-described principle, and in particular, a novel for realizing a multi-axis angular velocity sensor using micromachining technology and semiconductor technology. Is to provide a simple method. By applying the present invention, it is possible to mass-produce small and highly accurate multi-axis angular velocity sensors.

(1) According to a first aspect of the present invention, in the angular velocity sensor,
A substrate having an upper surface along the XY plane in an XYZ three-dimensional coordinate system; a weight body that performs rotational movement in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis;
Energy supply means for supplying energy to the weight body so that the weight body performs a rotational movement while maintaining a certain distance with respect to the upper surface of the substrate in a state where no external force acts;
X-axis upward distance measuring means for measuring the distance between the upper surface of the substrate and the passing weight body when the weight body passes over the X-axis;
And the angular velocity around the X-axis acting on the substrate is detected based on the distance measured by the X-axis upward distance measuring means.

(2) According to a second aspect of the present invention, in the angular velocity sensor according to the first aspect described above,
Providing a first weight body and a second weight body that rotate in a non-contact state with respect to the upper surface of the substrate with the Z axis as a rotation axis;
The first weight body and the second weight body are arranged so that the second weight body is located above the negative X axis when the first weight body is located above the positive X axis. Rotate the phase by 180 degrees,
Positive X-axis upward distance measuring means for measuring the distance between the upper surface of the substrate and the passing weight body when any weight body passes over the positive X-axis;
Negative X-axis upward distance measuring means for measuring the distance between the upper surface of the substrate and the passing weight body when any weight body passes over the negative X-axis;
Difference calculating means for obtaining a difference between the distance measured by the positive X-axis upward distance measuring means and the distance measured by the negative X-axis upward distance measuring means;
And the angular velocity around the X axis acting on the substrate is detected based on the difference obtained by the difference calculating means.

(3) According to a third aspect of the present invention, in the angular velocity sensor according to the first aspect described above,
Y-axis upward distance measuring means for measuring the distance between the substrate upper surface and the weight body when the weight body passes over the Y-axis is further provided,
Based on the distance measured by the X-axis upward distance measuring means, the angular velocity around the X-axis acting on the substrate is detected, and on the basis of the distance measured by the Y-axis upward distance measuring means, the Y-axis acting on the substrate The angular velocity around is detected.

(4) According to a fourth aspect of the present invention, in the angular velocity sensor according to the third aspect described above,
Providing a first weight body and a second weight body that rotate in a non-contact state with respect to the upper surface of the substrate with the Z axis as a rotation axis;
When the first weight body is positioned above the positive X axis, the second weight body is positioned above the negative X axis, and when the first weight body is positioned above the positive Y axis The first weight body and the second weight body are rotated by shifting the phase by 180 ° so that the second weight body is positioned above the negative Y axis.
Positive X-axis upward distance measuring means for measuring the distance between the upper surface of the substrate and the passing weight body when any weight body passes over the positive X-axis;
Negative X-axis upward distance measuring means for measuring the distance between the upper surface of the substrate and the passing weight body when any weight body passes over the negative X-axis;
Positive Y-axis upward distance measuring means for measuring the distance between the upper surface of the substrate and the passing weight body when any weight body passes over the positive Y-axis;
Negative Y-axis upward distance measuring means for measuring the distance between the upper surface of the substrate and the passing weight body when any weight body passes over the negative Y-axis;
First difference calculating means for obtaining a difference between the distance measured by the positive X-axis upward distance measuring means and the distance measured by the negative X-axis upward distance measuring means;
Second difference calculation means for obtaining a difference between the distance measured by the positive Y-axis upward distance measurement means and the distance measured by the negative Y-axis upward distance measurement means;
And detecting the angular velocity around the X-axis acting on the substrate based on the difference obtained by the first difference calculating means, and detecting Y acting on the substrate based on the difference obtained by the second difference calculating means. The angular velocity around the axis is detected.

(5) According to a fifth aspect of the present invention, in the angular velocity sensor according to the fourth aspect described above,
In addition to the first weight body and the second weight body, a third weight body and a fourth weight body that perform rotational movement in a non-contact state with respect to the upper surface of the substrate about the Z axis as a rotation axis. A weight,
When the first weight body is located above the positive X axis, the second weight body is located above the negative X axis, and the third weight body is located above the positive Y axis, The first weight body, the second weight body, the third weight body, and the fourth weight body are interposed through the intermediate member so that the fourth weight body is positioned above the negative Y axis. Are combined.

(6) According to a sixth aspect of the present invention, in the angular velocity sensor according to the second, fourth, and fifth aspects described above,
The plurality of weight bodies used have the same shape and mass.

(7) According to a seventh aspect of the present invention, in the angular velocity sensor according to the first to sixth aspects described above,
Prepare an annular structure that surrounds the periphery of the Z axis, and use the energy supplied from the energy supply means to rotate the annular structure in a non-contact state with respect to the upper surface of the substrate with the Z axis as the rotation axis. Thus, a part of the annular structure is regarded as one weight body, and is used as a target for distance measurement.

(8) According to an eighth aspect of the present invention, in the angular velocity sensor according to the first to seventh aspects described above,
The rotational motion of the weight body is always a continuous rotational motion in the same rotational direction.

(9) According to a ninth aspect of the present invention, in the angular velocity sensor according to the eighth aspect described above,
A pivot fixed to the upper surface of the substrate is provided so as to extend along the Z axis, and the weight body is supported by the pivot so as to be rotatable and movable in the Z axis direction with a predetermined degree of freedom. It is a thing.

(10) According to a tenth aspect of the present invention, in the angular velocity sensor according to the first to seventh aspects described above,
The rotational motion of the weight body is a reverse rotational motion that alternately repeats the rotation in the clockwise direction and the rotation in the counterclockwise direction.

(11) An eleventh aspect of the present invention is the angular velocity sensor according to the tenth aspect described above,
A first weight body that performs a reversal rotation motion across the positive X axis, a second weight body that performs a reversal rotation motion across the negative X axis, and a positive Y axis The first weight body and the second weight body are provided with a third weight body that performs the reverse rotation motion and a fourth weight body that performs the reverse rotation motion so as to cross the negative Y axis. The rotation direction of the reverse rotation motion of the third weight body and the rotation direction of the reverse rotation motion of the fourth weight body are always set to be opposite to each other.

(12) According to a twelfth aspect of the present invention, in the angular velocity sensor according to the tenth or eleventh aspect described above,
A support made of a material capable of twisting around the Z-axis is fixed to the upper surface of the substrate, and the weight body is supported by this support.

(13) According to a thirteenth aspect of the present invention, in the angular velocity sensor according to the first to twelfth aspects described above,
At least a part of the weight body is made of a dielectric,
The energy supply means is configured by a plurality of electrodes arranged along the rotational movement path of the weight body, and a voltage supply circuit that supplies alternating voltages having different phases to the plurality of electrodes.

(14) According to a fourteenth aspect of the present invention, in the angular velocity sensor according to the first to thirteenth aspects,
Distance measuring means for measuring the distance between the weight body passing over the predetermined coordinate axis and the upper surface of the substrate, a moving electrode formed on the lower surface of the weight body, a fixed electrode formed near the coordinate axis on the upper surface of the substrate, And a detection circuit for detecting a capacitance value of a capacitive element constituted by a moving electrode and a fixed electrode.

(15) According to a fifteenth aspect of the present invention, in the angular velocity sensor according to the fourteenth aspect described above,
The fixed electrode is constituted by a first fixed electrode and a second fixed electrode arranged adjacent to each other,
The moving electrode is constituted by an electrically single electrode that can face both the first fixed electrode and the second fixed electrode,
The detection circuit is configured by a circuit that electrically detects a capacitance value between the first fixed electrode and the second fixed electrode.

(16) According to a sixteenth aspect of the present invention, in the angular velocity sensor,
A substrate having an upper surface along the XY plane in an XYZ three-dimensional coordinate system; a weight body that performs rotational movement in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis;
Energy supply means for supplying energy to the weight body so that the weight body performs a rotational movement while maintaining a constant distance with respect to the Z axis in a state where no external force is applied;
Distance measuring means for measuring the distance between the weight body and the Z axis;
The angular velocity around the Z-axis acting on the substrate is detected based on the distance measured by the distance measuring means.

(17) According to a seventeenth aspect of the present invention, in the angular velocity sensor according to the sixteenth aspect described above,
Providing a first weight body and a second weight body that rotate in a non-contact state with respect to the upper surface of the substrate with the Z axis as a rotation axis;
The first weight body and the second weight body are arranged so that the second weight body is located above the negative X axis when the first weight body is located above the positive X axis. Rotate the phase by 180 degrees,
A positive X-axis distance measuring means for measuring a distance to the Z-axis when any weight body passes over the positive X-axis;
Negative X-axis distance measuring means for measuring the distance to the Z-axis when any weight body passes over the negative X-axis;
Arithmetic means for calculating the sum of the distance measured by the positive X-axis distance measuring means and the distance measured by the negative X-axis distance measuring means;
The angular velocity around the Z-axis acting on the substrate is detected based on the sum obtained by the calculation means.

(18) According to an eighteenth aspect of the present invention, in the angular velocity sensor according to the seventeenth aspect described above,
The rotational motion of the weight body is always a continuous rotational motion in the same rotational direction.

(19) According to a nineteenth aspect of the present invention, in the angular velocity sensor according to the eighteenth aspect described above,
The first weight body and the second weight body are joined using an intermediate member having elasticity,
A pivot fixed to the upper surface of the substrate is provided so as to extend along the Z axis, and the intermediate member is rotatably supported by the pivot.

(20) According to a twentieth aspect of the present invention, in the angular velocity sensor according to the seventeenth aspect described above,
The rotational motion of the weight body is a reversal rotational motion in which the rotation in the clockwise direction and the rotation in the counterclockwise direction are alternately repeated.

(21) According to a twenty-first aspect of the present invention, in the angular velocity sensor according to the twentieth aspect described above,
A support made of a material capable of causing twisting around the Z axis is fixed to the upper surface of the substrate, and the weight body is supported by the support through an intermediate member having elasticity. .

(22) According to a twenty-second aspect of the present invention, in the angular velocity sensor according to the sixteenth to twenty-first aspects described above,
At least a part of the weight body is made of a dielectric,
The energy supply means is configured by a plurality of electrodes arranged along the rotational movement path of the weight body, and a voltage supply circuit that supplies alternating voltages having different phases to the plurality of electrodes.

(23) According to a twenty-third aspect of the present invention, in the angular velocity sensor according to the sixteenth to twenty-second aspects described above,
A distance measuring means for measuring the distance between the weight body and the Z-axis is provided by a predetermined offset amount inside or outside the moving electrode formed on the lower surface of the weight body and the position facing the moving electrode on the upper surface of the substrate. This is constituted by a fixed electrode formed at a shifted position and a detection circuit for detecting a capacitance value of a capacitive element constituted by the moving electrode and the fixed electrode.

(24) According to a twenty-fourth aspect of the present invention, in the angular velocity sensor according to the twenty-third aspect described above,
The fixed electrode is constituted by a first fixed electrode and a second fixed electrode arranged adjacent to each other,
The moving electrode is constituted by an electrically single electrode that can face both the first fixed electrode and the second fixed electrode,
The detection circuit is configured by a circuit that electrically detects a capacitance value between the first fixed electrode and the second fixed electrode.

  By using the present invention, a multi-axis angular velocity sensor using micromachining technology and semiconductor technology can be realized, and a small and highly accurate multi-axis angular velocity sensor can be mass-produced.

<<< §1. Basic principle of the present invention >>
First, the basic principle of the angular velocity sensor according to the present invention will be described with reference to FIG. The angular velocity sensor shown in FIG. 1 has a function of detecting angular velocities ωx and ωy around the X axis and the Y axis in the XYZ three-dimensional coordinate system. The substrate 10 has a flat upper surface 11 and functions as an apparatus housing. Here, the XYZ three-dimensional coordinate system is defined so that the upper surface 11 is included in the XY plane, and the Z axis extending upward from the origin O is an axis orthogonal to the upper surface 11. Now, it is assumed that a weight body 20 having a predetermined mass is prepared, and the weight body 20 is rotationally moved along a trajectory C shown in the drawing with the Z axis as a rotation axis. That is, the weight body 20 performs a rotational movement in a non-contact state with respect to the upper surface 11 of the substrate 10. At this time, energy for rotational motion is supplied from the energy supply means 30 to the weight body 20 so that the weight body 20 performs rotational motion while maintaining a constant distance h with respect to the upper surface 11. To do.

  Of course, in an actual angular velocity sensor, a specific mechanism for supporting the weight body 20 with respect to the substrate 10, or a specific mechanism for rotating the surface while maintaining a certain distance h in a non-contact state with the upper surface 11. Such a specific mechanism will be described in detail in §5 and later. Here, unless an extra force (external force) from outside the system such as a Coriolis force or a force based on acceleration is applied (that is, as long as the substrate 10 is in a stationary state), a constant distance h is always maintained from the upper surface 11. On the other hand, it is assumed that some mechanism for causing the weight body 20 to rotate is provided.

  This angular velocity sensor further includes an X-axis upward distance measuring means 40 for measuring the distance between the upper surface 11 and the passing weight body 20 when the weight body 20 passes over the X-axis, and the weight body 20. Is provided with Y-axis upward distance measuring means 50 for measuring the distance between the upper surface 11 and the passing weight body 20 at the time of passing over the Y-axis. As described above, the weight body 20 always moves at a height of a distance h from the upper surface 11 in a state where a force from outside the system does not act. In other words, the weight body 20 moves along a circular orbit C on the plane indicated by the equation Z = h. Therefore, in this state, the measured value by the X-axis upward distance measuring means 40 and the measured value by the Y-axis upward distance measuring means 50 are both the steady state distance h.

  However, when the entire system is rotating at an angular velocity ωx around the X axis or an angular velocity ωy around the Y axis, in other words, when the angular velocity ωx or ωy acts on the substrate 10, this angular velocity Therefore, the Coriolis force based on the above acts on the weight body 20, and the movement of the weight body 20 deviates from the original circular orbit C.

Here, the relationship between the angular velocity acting on the moving object and the Coriolis force will be briefly described with reference to FIG. Now, as shown in FIG. 2, a case is considered in which a weight body 20 having a predetermined mass m is moving at a predetermined speed Vy in the Y-axis direction in an XYZ three-dimensional coordinate system. At this time, if the entire coordinate system is rotated at an angular velocity ωx around the X axis, the motion of the weight body 20 in the coordinate system can be handled as if the external force Fcz in the Z axis direction was generated. . This external force Fcz is an apparent force that appears only in this system and is called Coriolis force.
Fcz = 2 ・ m ・ Vy ・ ωx
Is defined by the expression In the example shown in FIG. 2, the orbit of the weight body 20 moving in the Y-axis direction is bent in the Z-axis direction by the action of the Coriolis force Fcz.

Therefore, the action of the Coriolis force on the weight body 20 when the angular velocity ωx around the X axis is applied to the entire system shown in FIG. As shown in FIG. 3, the weight body 20 has a velocity component Vy in the Y-axis direction that is a tangential direction of the circular orbit C at the moment of passing over the X-axis. Accordingly, when the angular velocity ωx around the X axis acts on the entire system at this moment, the Coriolis force Fcz acts in the Z axis direction. The energy supply means 30 supplies energy for rotating the weight body 20 along the original circular orbit C (orbit planned when the angular velocity ωx = 0). When the Coriolis force Fcz in the Z-axis direction is applied, the weight body 20 deviates from the original circular orbit C by Δh in the Z-axis direction and passes through a point separated by a distance h + Δh from the substrate upper surface 11 as shown in the figure. Will do. The distance Δh from the initial circular orbit C is a value related to the applied Coriolis force Fcz. As mentioned above, the magnitude of this Coriolis force Fcz is
Fcz = 2 ・ m ・ Vy ・ ωx
Therefore, if the mass m and the motion speed Vy of the weight body 20 are kept constant, the Coriolis force Fcz becomes a value proportional to the angular speed ωx, and eventually the weight body 20 passes above the X axis. The distance Δh from the initial circular orbit C at the time of the operation can be used as a value indicating the angular velocity ωx. Since h is constant, if the distance h + Δh between the weight body 20 and the substrate upper surface 11 can be measured, the value of the angular velocity ωx can be obtained.

  The angular velocity sensor shown in FIG. 1 has a function of detecting an angular velocity ωx around the X axis and an angular velocity ωy around the Y axis based on such a principle. That is, when the substrate 10 as the sensor housing is attached to the measurement target and energy is supplied from the energy supply means 30, the weight body 20 rotates along the circular orbit C. In this state, the X-axis upward distance measuring means 40 outputs a measured value of the distance from the substrate upper surface 11 when the weight body 20 passes above the X-axis, and the Y-axis upward distance measuring means 50 outputs A measured value of the distance from the substrate upper surface 11 when the weight body 20 passes above the Y axis is output. Therefore, the output of the X-axis upward distance measuring means 40 indicates the angular velocity ωx around the X-axis of the substrate 10 (that is, the angular speed ωx of the object to be measured), and the output of the Y-axis upward distance measuring means 50 is It shows the angular velocity ωy around the Y axis of the substrate 10 (that is, the angular velocity ωy of the object to be measured).

  When a reverse angular velocity is applied, the direction of the generated Coriolis force is reversed, and the sign of the distance Δh from the circular orbit C is reversed, so that the weight body 20 and the substrate upper surface 11 are reversed. The direction of the acting angular velocity can be recognized depending on whether the distance h has increased or decreased.

<<< §2. Cancel acceleration component >>>
Considering the environment in which the angular velocity sensor is actually used, an environment in which only a pure angular velocity acts is very rare, and usually it is often used in an environment in which both acceleration and angular velocity act. When it is assumed to be used in such a general environment, a function for accurately detecting only the angular velocity without being affected by acceleration is required.

  In fact, the angular velocity sensor described in the above section 1 cannot accurately detect the angular velocity in an environment where acceleration acts. That is, in FIG. 3, in an environment where only the angular velocity ωx is acting, the distance Δh is an amount based only on the Coriolis force Fcz proportional to the angular velocity ωx, and the measured value of Δh indicates the angular velocity ωx. Become. However, when the acceleration αz in the Z-axis direction acts on the entire system, a force Faz based on the acceleration αz is applied to the weight body 20, and the distance Δh is a Coriolis force proportional to the angular velocity ωx. Since the amount is determined by both Fcz and the force Faz based on the acceleration αz, the measured Δh value includes an acceleration component, and an accurate angular velocity ωx cannot be obtained.

  Of course, a general acceleration sensor is used in combination with the angular velocity sensor described in §1, and the acceleration value detected by the acceleration sensor is corrected to cancel the acceleration component. Is also possible. However, the device configuration that is always premised on the combined use with the acceleration sensor must be complicated, which is not preferable from the viewpoint of downsizing and cost reduction of the device. Although the angular velocity sensor described in §2 basically adopts the principle of the angular velocity sensor described in §1, it is possible to easily obtain a detection value in which the acceleration component is canceled.

  FIG. 4 shows a basic configuration of an angular velocity sensor having a function of canceling the acceleration component. This sensor is characterized in that a pair of weight bodies 21 and 22 are provided on the track C. Each of the weight bodies receives the supply of energy from the energy supply means 30 and performs a rotational movement in a non-contact state with respect to the substrate upper surface 11 with the Z axis as a rotation axis. However, as illustrated, when the first weight body 21 is located above the positive X axis, the first weight body 22 is located above the negative X axis. And the second weight body rotate in a state where the phases are shifted from each other by 180 °. Therefore, when the first weight body 21 is located above the positive Y axis, the second weight body 22 is located above the negative Y axis.

  The angular velocity sensor is provided with four sets of distance measuring means. That is, the positive X-axis upward distance measuring means 41 has the substrate upper surface 11 when any weight body passes over the positive X-axis (the point where the first weight body 21 exists in FIG. 4). The negative X-axis upward distance measuring means 42 has a function of measuring the distance between the weight and the passing weight body. It has a function of measuring the distance between the upper surface 11 of the substrate and the passing weight body at the time of passing through the point where the weight body 22 exists. The positive Y-axis upward distance measuring means 51 has a function of measuring the distance between the substrate upper surface 11 and the passing weight body when any weight body passes over the positive Y-axis. The negative Y-axis upward distance measuring means 52 has a function of measuring the distance between the substrate upper surface 11 and the passing weight body when any weight body passes over the negative Y-axis.

  Further, a first difference calculating means 43 for obtaining a difference between the distance measured by the positive X-axis upward distance measuring means 41 and the distance measured by the negative X-axis upward distance measuring means 42, positive Y And a second difference calculation means 53 for determining a difference between the distance measured by the axial upward distance measuring means 51 and the distance measured by the negative Y-axis upward distance measuring means 52, and finally. Based on the outputs of the difference calculation means 43 and 53, the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis are detected.

  Next, the detection principle and the reason for canceling the acceleration component in this angular velocity sensor will be described. Now, as shown in FIG. 4, a pair of weight bodies 21 and 22 rotate on a circular orbit C included on a plane indicated by Z = h with a phase shifted by 180 ° from each other. Let us consider a state in which energy is supplied from the energy supply means 30 to be performed. In this state, as shown in the figure, the first weight body 21 passes over the positive X-axis with a velocity Vy in the Y-axis positive direction, and at the same time, the second weight body 22 passes over the negative X-axis. Through Y-axis negative direction speed -Vy. At this time, if an angular velocity ωx around the X axis is acting on the entire system, the Coriolis force in the Z-axis positive direction is applied to the first weight body 21 as shown in FIG. Fcz is added, and the first weight body 21 deviates upward from the original circular orbit C. On the other hand, a negative Coriolis force -Fcz in the Z-axis direction is applied to the second weight body 22, and the second weight body 22 is moved downward from the original circular orbit C.

  Now, it is assumed that the first weight body 21 and the second weight body 22 have exactly the same shape and the completely same mass. Here, since they are always rotating with a phase difference of 180 °, the absolute value of the speed of the rotating motion is the same. Therefore, the absolute value of the Coriolis force acting on both weight bodies is the same, and the first weight body 21 is deviated upward from the circular orbit C by Δh and passes the position of the distance h + Δh from the substrate upper surface 11. In this case, the second weight body 22 deviates downward from the circular orbit C by Δh, and passes through the position of the distance h−Δh from the upper surface 11 of the substrate. Therefore, the output of the positive X-axis upward distance measuring means 41 is h + Δh, and the output of the negative X-axis upward distance measuring means 42 is h−Δh. Eventually, the difference calculation means 43 outputs 2 · Δh, which is the difference between the two. This difference 2 · Δh indicates the magnitude of the applied Coriolis force Fcz (−Fcz), and indicates the magnitude of the angular velocity ωx around the X axis. When the direction of the applied angular velocity ωx is opposite, the direction of the Coriolis force is reversed, and the output from the difference calculation means 43 is −2 · Δh. Therefore, the sign of the output signal obtained from the difference calculation means 43 indicates the direction of the angular velocity ωx, and the magnitude of the output signal indicates the magnitude of the angular velocity ωx.

  Here, even if acceleration acts on the entire system, this acceleration does not affect the detection result. That is, even if some acceleration component acts on the entire system, the force based on this acceleration component is applied to both the first weight body 21 and the second weight body 22, It is canceled when the difference is taken. For example, in the example shown in FIG. 5, since the acceleration αz in the Z-axis direction is applied, it is assumed that both weight bodies are further displaced by Δk in the positive Z-axis direction due to the force Faz based on the acceleration αz. In this case, the output of the positive X-axis upward distance measuring means 41 is h + Δh + Δk, the output of the negative X-axis upward distance measuring means 42 is h−Δh + Δk, and the difference output from the difference calculating means 43 is still 2 · Δh. Become. That is, since the difference is taken, the influence of the acceleration αz is canceled.

  As described above, the acceleration component can be canceled by using the pair of weight bodies that perform the rotational motion in a state where the phases are shifted from each other by 180 °.

  In the above description, the positive X-axis upward distance measuring means 41, the negative X-axis upward distance measuring means 42, and the difference calculating means 43 that takes the difference between the outputs of these two measuring means are used. The operation of detecting the angular velocity ωx of the positive Y-axis upward distance measuring means 51 and the negative Y-axis upward distance measuring means 52, and the difference calculating means 53 for taking the difference between the outputs of these measuring means are used. For example, the angular velocity ωy about the Y axis can be detected based on the same principle. In this way, the angular velocity ωx around the X axis is detected at the moment when both weight bodies 21 and 22 pass above the positive X axis and above the negative X axis, and above the positive Y axis and above the negative Y axis. If the angular velocity ωy around the Y-axis is detected at the moment of passing, the angular velocities ωx and ωy can be detected alternately. The detection cycle can be adjusted by the rotational speed of the weight bodies 21 and 22.

<<< §3. Rotor structure with weight body >>>
In §2 described above, the method of canceling the acceleration component by rotating the pair of weights with the phases shifted by 180 ° from each other has been described. In principle, the pair of weights may be configured as completely separate objects, but in practice, it is preferable to prepare the pair of weights as a single structure. . Although the acceleration component can be canceled by using at least two weight bodies, it is preferable to use a larger number of weight bodies in practice.

  Here, an embodiment in which a rotor is formed by connecting a plurality of weight bodies to each other will be described. The embodiment shown in FIG. 6 is an example in which the rotor 60 is formed by connecting four sets of weight bodies 21, 22, 23, 24 via arms 61, 62, 63, 64. The four arms 61 to 64 are arranged on a plane of Z = h, and are coupled to each other at a point P while maintaining an angle of 90 °. Weight bodies 21-24 are coupled to the outer end portions of the respective arms. When such a rotor 60 is rotated around the point P, the four weight bodies 21-24 are The rotary motion is performed on the circular orbit C with a phase difference of 90 ° from each other. Thus, since the four weight bodies 21-24 are arranged with a phase difference of 90 ° from each other, when the first weight body 21 is positioned above the positive X-axis as in the state shown in the figure. The second weight body 22 is located above the negative X axis, the third weight body 23 is located above the positive Y axis, and the fourth weight body is located above the negative Y axis. It becomes like this. Therefore, if the distance between each weight body and the substrate upper surface 11 is measured at this moment, the angular velocity around the X axis is based on the measurement results regarding the first weight body 21 and the second weight body 22. ωx can be detected, and at the same time, the angular velocity ωy around the Y-axis can be detected based on the measurement results relating to the third weight body 23 and the fourth weight body 24.

  In order to perform such detection, the center point P of the rotor 60 must be supported at a predetermined position on the Z-axis. In this case, the following two conditions are satisfied. is required. The first condition is that each weight body 21-24 can rotate about the Z axis as a rotation axis, and the Coriolis force acting on the weight body during the rotational motion is detected. This condition is indispensable for realizing the basic principle. The second condition is that each weight body 21-24 is movable with a predetermined degree of freedom in the Z-axis direction, and the Coriolis force is detected as a change in the distance from the substrate upper surface 11. In order to achieve this, it is indispensable that each weight body is configured to be movable within a necessary range in the Z-axis direction.

  FIG. 7 is a plan view showing a more practical configuration of the rotor 60 shown in FIG. The four weight bodies 21-24 are connected to the outer end portions of the four arms 61-64, and the inner end portions of the four arms 61-64 are the center disposed in the vicinity of the center point P. It is connected to the member 65. The rotor 60 has rigidity as a whole, and rotates around the center point P as indicated by an arrow in the figure.

  At the instant shown in the drawing, the first weight body 21 passes through the positive X axis with the speed Vy in the Y axis positive direction, and the second weight body 22 has a negative X speed with the speed −Vy in the Y axis negative direction. Pass through the axis. Therefore, in an environment in which an angular velocity ωx around the X axis is acting, a Coriolis force Fcz in the Z-axis positive direction acts on the first weight body 21 and acts on the second weight body 22. Thus, the Coriolis force -Fcz in the Z-axis negative direction acts, and the angular velocity ωx is detected as the difference between the two. Similarly, the third weight body 23 passes through the positive Y axis at a speed −Vx in the X axis negative direction, and the fourth weight body 24 passes through the negative Y axis at a speed Vx in the X axis positive direction. Therefore, in an environment where the angular velocity ωy around the Y axis is acting, Coriolis forces in opposite directions act on the third weight body 23 and the fourth weight body 24, respectively, and the difference between the two Angular velocity ωy is detected.

  As already described in §2, the influence of acceleration can be canceled by taking the difference. Further, depending on the action of the angular velocity ωx, no Coriolis force is generated for the third weight body 23 and the fourth weight body 24 having a velocity component in the X-axis direction. Similarly, the angular velocity Depending on the action of ωy, no Coriolis force is generated for the first weight body 21 and the second weight body 22 having the velocity component in the Y-axis direction. Therefore, even in an environment where both the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis are acting, it is possible to detect both of them independently and to cause interference between them. There is no.

  Further, when the angular velocity ωz around the Z axis is acting, the angular velocity sensor according to the present invention cannot detect the angular velocity ωz itself, but the detection result of the angular velocity ωx or the angular velocity ωz due to the presence of the angular velocity ωz. Will not be affected. For example, even if the Coriolis force Fcx directed in the X-axis positive direction acts on the first weight body 21 due to the angular velocity ωz, the second weight body 22 moves in the X-axis negative direction. Since the Coriolis force -Fcx acts, the influence of these Coriolis forces is canceled for the rotor 60 as a whole.

  As described above, when the rotor 60 shown in FIG. 7 is used, detection values of both the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis can be obtained every time the rotor 60 rotates 90 °. . In order to shorten this detection cycle, the rotational speed of the rotor 60 may be increased, but the number of weight bodies may be increased. For example, FIG. 8 is a plan view of a rotor 68 including eight weight bodies 21-28. When such a rotor 68 is used, detection values of both the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis can be obtained every time the rotor 68 rotates 45 °, and the rotor 60 shown in FIG. As compared with the case of using, even if the rotation speed is the same, the detection cycle can be shortened to ½.

  In addition, when forming a rotor using a several weight body, it is preferable to make the shape and mass of each weight body the same. Of course, the present invention can be realized even if a plurality of weight bodies having different shapes or masses are used, but it is not practical because it is necessary to perform a correction operation in consideration of the mass and moment in order to cancel the acceleration component. .

  The rotor 70 shown in FIG. 9 includes four arms 71-74, a central member 75 connected to the inner end thereof, and an annular structure 76 connected to the outer end thereof. The center point P is supported on the Z axis, and the annular structure 76 is rotationally moved in a non-contact state with respect to the substrate upper surface 11 about the Z axis as a rotation axis by using energy supplied from the energy supply means 30. Then, this annular structure 76 functions as a number of weight bodies. That is, if a part of the annular structure 76 is regarded as one weight body and is a target for distance measurement, angular velocity detection based on the above-described principle can be performed. For example, as shown in FIG. 9, if mass points M1-M4 are defined on the annular structure 76 and these mass points are regarded as weight bodies 21-24, respectively, the rotor 70 is the same as the rotor 60 shown in FIG. Become equivalent.

  In principle, the rotor 70 having the annular structure 76 functions as a rotor having an infinite number of weights, so that the angular velocity detection cycle can be shortened to zero and continuous in time. It is possible to obtain the detected value.

<<< §4. Reversal rotation of rotor >>>
In all the examples described so far, the rotor as the weight body or its assembly is always moved in the same rotational direction. For example, in the example using the rotor 60 shown in FIG. 7, the entire rotor 60 is rotated “counterclockwise” around the point P, and the rotation direction “counterclockwise” remains unchanged. A continuous rotational motion will be performed.

  However, according to the basic principle of the present invention, it is only necessary to repeatedly execute a motion in which the weight body crosses the X-axis or Y-axis with a velocity component perpendicular to the axis. There is no need to continuously rotate the body.

  For example, as shown in FIG. 10, even if the rotor 60 is rotated in the reverse direction, angular velocity detection based on the basic principle of the present invention is possible. Here, the reverse rotation movement refers to a movement that alternately repeats the rotation in the clockwise direction and the rotation in the counterclockwise direction. In the example shown in FIG. 10, the rotation of the first half cycle (rotation in the clockwise direction) in which each weight body 21-24 is moved from position A to position B, and conversely from position B to position A. The second half period of rotational movement (rotational movement in the counterclockwise direction) to be moved to is repeated alternately. Since the X-axis or Y-axis is located between the positions AB, the weight body crosses over the X-axis or Y-axis with a velocity component perpendicular to the axis in each of the first half cycle and the second half cycle. In short, each weight body repeats reciprocating motion along an arcuate trajectory. In other words, each weight body will oscillate along an arc that crosses each axis, and in particular, if it is made to oscillate at a specific resonance frequency, efficient reciprocation is possible. Become.

  However, it is necessary to note that the sign of the detected value is inverted between the first half period and the second half period when such a reversal rotational motion is performed. That is, the detection value obtained when the weight body crosses over each axis in the first half cycle in which the weight body moves from position A to position B, and each axis in the second half cycle in which the weight body moves from position B to position A. The detected value obtained when crossing the sky is reversed in sign because the direction of the Coriolis force acting is reversed. Therefore, for example, a process for reversing the sign is necessary for the detection value obtained in the second half cycle.

  As described above, “rotational motion” in this specification includes both “continuous rotational motion” in which the rotational direction is always constant and “inverted rotational motion (vibration)” in which the rotational direction is periodically reversed. It is used in a broad concept, and the rotation angle with respect to the center does not need to cover the entire range of 360 °. As shown in FIG. 10, a constant angle θ corresponding to the position AB defined on both sides of the X axis or the Y axis is used. It is enough to rotate only.

  The merit of rotating the rotor in a reverse rotation without continuously rotating is that the support mechanism of the rotor is simplified as in the embodiment of §8 described later. That is, in the case of reverse rotation motion, it is not necessary to rotate the rotor by 360 °, and it is sufficient to rotate the rotor by the angle θ shown in FIG. 10, so that the twist can be generated around the Z axis by the angle θ. In this manner, the rotor may be fixed on the substrate. In short, it is possible to adopt a simple structure in which a support made of a material capable of twisting around the Z-axis is fixed on the substrate and the rotor (weight body) is supported by this support.

  However, when such a simple structure is adopted, vibration due to the reversal rotation of the rotor propagates from the substrate to the apparatus housing via the support. That is, because the entire rotor rotates in the clockwise direction in the first half cycle, this clockwise rotating element propagates to the housing, and in the second half cycle, the entire rotor rotates in the counterclockwise direction. This counterclockwise rotating element propagates to the housing. In this manner, the vibration component of the rotor leaking into the apparatus housing is not preferable for accurate detection. For example, just touching the device housing affects the reverse rotation of the rotor, and the detection result is also affected by the manner in which the device housing is attached to the object to be measured.

  In order to prevent such vibration leakage, the reverse rotation motion may be performed in such a manner that the clockwise rotation and the counterclockwise rotation cancel each other. Specifically, in the first half cycle, as shown in FIG. 11, the first weight body 21 and the second weight body 22 (the weight body crossing the X axis) are moved from the position A to the position B. The third weight body 23 and the fourth weight body 24 (weight bodies crossing the Y axis) are rotated counterclockwise so as to move from the position B to the position A. Rotate in the direction. Then, in the second half cycle, as shown in FIG. 12, the first weight body 21 and the second weight body 22 (weight bodies crossing the X axis) are moved from the position B toward the position A. Rotate in the clockwise direction, and rotate the third weight body 23 and the fourth weight body 24 (weight bodies crossing the Y axis) in the clockwise direction so as to go from position A to position B. Exercise.

  Thus, the rotation direction of the reverse rotation motion of the first weight body 21 and the second weight body 22 and the rotation direction of the reverse rotation motion of the third weight body 23 and the fourth weight body 24 are as described above. Is always set in the opposite direction, the clockwise vibration component and the counterclockwise vibration component cancel each other in the rotor 60, and vibration leakage to the apparatus housing is suppressed. Is possible. However, when such a driving method is adopted, it is necessary to make the arms 61, 62, 63, 64 constituting the rotor 60 have a certain degree of flexibility (the flexibility of the arms). Can be adjusted by thickness, for example).

<<< §5. Specific Example of Angular Velocity Sensor of the Present Invention >>
Subsequently, the angular velocity sensor according to the present invention will be described based on a more specific embodiment. FIG. 13 is a plan view of this embodiment, and FIG. 14 is a side sectional view showing a state in which this embodiment is cut along the X axis. This embodiment is an angular velocity sensor that can be manufactured using micromachining technology and semiconductor technology, and all necessary components are formed on a semiconductor substrate.

  The main components of this angular velocity sensor are a substrate 100 and a rotor 200. As shown in FIG. 14, the substrate 100 includes a silicon substrate 101 and a silicon oxide film 102 formed on the silicon substrate 101. Here, the upper surface 103 of the substrate is included in the XY plane. An XYZ three-dimensional coordinate system is defined and described below.

  A rotor 200 is disposed on the upper surface 103 of the substrate 100. As clearly shown in the plan view of FIG. 15, the rotor 200 basically has the same structure as the rotor 60 shown in FIG. 7. That is, the four arms 221-224 are arranged with an angle difference of 90 ° from each other, and the inner end portions thereof are connected to the central member 225 having a thick cylindrical shape. Also, weight bodies 211-214 are connected to the outer ends of the arms 221-224, respectively. The four arms 221-224 and the four weight bodies 211-214 are all the same in shape and mass.

  The main body of the rotor 200 is made of a dielectric material, and a conductive electrode is formed on the lower surface thereof. That is, the weight bodies 211-214, the arms 221-224, and the central member 225 constituting the main body of the rotor 200 are all made of a dielectric material (polysilicon in this example). Moving electrodes 231-235 made of a conductive material (in this example, aluminum or polysilicon doped with high-concentration impurities) are formed on the lower surfaces of 211-214 and the central member 225 (moving electrodes 233 and 234). Is shown in FIG. The reason why the main body portion of the rotor 200 is made of a dielectric material is to cause the rotor 200 to perform a rotational motion by the principle of an induction motor, as will be described in detail in §6. The reason why the moving electrodes 231-234 are formed on the lower surfaces of the respective weight bodies 211-214 is that the distance between the weight bodies 211-214 and the substrate upper surface 103 is measured as described in detail in §7. This is for forming a capacitor element.

  It is not necessary to form the electrode 235 on the lower surface of the central member 225. However, when a general semiconductor manufacturing process is performed, in the step of forming the moving electrode layer on the lower surface of each weight body, the central member 225 The electrode layer 235 is also formed on the lower surface. Since this electrode layer 235 does not hinder the operation of the angular velocity sensor, in this embodiment, the electrode layer 235 is left as it is.

  A cylindrical pivot 130 is fixed on the substrate 100 so as to extend along the Z axis. As shown in FIG. 15, the center member 225 of the rotor 200 has a thick cylindrical shape, and a columnar cavity is formed at the center. The diameter of this cavity is slightly larger than the diameter of the pivot 130, and as shown in FIG. 14, when the rotor 200 is fitted to the pivot 130 by passing the pivot 130 through the cavity 130, the pivot 130. An air gap is formed between the outer peripheral portion and the inner peripheral portion of the cavity. By this gap, the rotor 200 is supported so as to be rotatable with respect to the pivot 130 and tilted with a predetermined degree of freedom (in other words, each weight body is movable in the Z-axis direction). Will be. A disc-shaped stopper 131 is attached to the upper end of the pivot 130 to prevent the rotor 200 from falling off the pivot 130. The pivot 130 and the stopper 131 may be made of any material, but are preferably made of an insulating material so as not to hinder electrical operation when the rotor 200 comes into contact.

  Note that FIG. 14 shows a state in which the rotor 200 has floated on the substrate 100, but this is because the rotor 200 is in a rotating motion, as will be described later.

  As can be seen from the plan view of FIG. 13, eight stator electrodes 111 to 118 are arranged on the substrate 100 so as to surround the periphery of the rotor 200. These stator electrodes 111 to 118 supply energy for rotating the rotor 200. In this embodiment, eight stator electrodes 111-118 are arranged on the X-axis, W1-axis, Y-axis, and W2-axis that intersect with each other with an angular difference of 45 ° along the rotational motion path of each weight body 211-214. Although it is arranged, more stator electrodes may be arranged in order to perform smoother rotational movement.

  Each stator electrode 111-118 is fixed on the substrate 100 via a pedestal made of an insulating material. For example, as shown in the side sectional view of FIG. 14, the stator electrode 111 is fixed on the substrate 100 via a pedestal 121, and the stator electrode 115 is fixed on the substrate 100 via a pedestal 125. Yes. In this embodiment, each pedestal is made of polysilicon, and the stator electrode is made of aluminum. The reason why each stator electrode is provided on the substrate 100 via an insulating pedestal is to make the floating rotation of the rotor 200 smoothly as described later.

  FIG. 16 is a plan view showing a state where the stopper 131 of the angular velocity sensor shown in FIG. 13 is removed and the rotor 200 is removed, and the state where the fixed electrodes 141A-144A, 141B-144B are arranged on the substrate 100 is shown. It is clearly shown. Each of these fixed electrodes is arranged in pairs near each coordinate axis. That is, the fixed electrode pair 141A, 141B is disposed near the positive X axis, the fixed electrode pair 142A, 142B is disposed near the negative X axis, and the fixed electrode pair 143A, 143B is disposed near the positive Y axis, The fixed electrode pair 144A, 144B is disposed near the negative X axis. Moreover, as indicated by broken lines in FIG. 13, the movements formed on the lower surface of each weight body when each weight body 211-214 of the rotor 200 passes over the X axis and the Y axis. Each fixed electrode 141A-144A, 141B-144B is arrange | positioned in the position which opposes the electrode 231-234.

  If each fixed electrode is arranged at the position as described above on the substrate 100, a capacitive element is formed at the position of each axis when each weight body 211-214 passes over the X axis and the Y axis. Will be. For example, FIG. 14 shows a state where the weight body 211 is positioned above the positive X axis and the weight body 212 is positioned above the negative X axis. In this state, the moving electrode 231 formed on the lower surface of the weight body 211 is opposed to both the fixed electrode pair 141A and 141B formed on the substrate 100, and a pair of capacitive elements is formed. Similarly, the moving electrode 232 formed on the lower surface of the weight body 212 faces both the fixed electrode pairs 142A and 142B formed on the substrate 100, and a pair of capacitive elements is formed. These capacitive elements are used to measure the distance between each weight body and the upper surface of the substrate, and details will be described in Section 7.

  FIG. 16 shows the voltage supply circuit 310 and the detection circuit 320 as a block diagram. The voltage supply circuit 310 is a circuit for supplying a predetermined voltage to each of the stator electrodes 111-118. Reference numeral 320 denotes a circuit for detecting the capacitance value of each capacitive element described above. Actually, wiring for voltage supply exists between each stator electrode 111-118 and the voltage supply circuit 310, and between each fixed electrode 141 A- 144 A, 141 B- 144 B and the detection circuit 320. There is also a capacitance detection wiring. However, in order to avoid the figure from becoming complicated, illustration of these wirings is omitted in FIG. In this embodiment, since the substrate 100 is a semiconductor substrate, the process of forming such wiring can be easily incorporated into the process of the semiconductor manufacturing process.

<<< §6. Principle of rotor rotation >>>
Here, the principle of the rotational operation of the rotor in the angular velocity sensor whose structure is described in §5 will be described. This principle has been known for a long time as the principle of an induction motor, and has recently been used as a principle for rotating a micromotor formed on a semiconductor substrate in fields such as micromachining. In the present embodiment, by supplying alternating voltages having different phases from the voltage supply circuit 310 to the stator electrodes 111-118, rotational energy is supplied to the rotor 200 made of a dielectric material.

  Now, as shown in FIG. 17, a predetermined voltage is applied between the stator electrode 111 and the stator electrode 115 to generate a positive charge on the stator electrode 111 side and a negative charge on the stator electrode 115 side. . Then, since the main body portion of the rotor 200 is made of a dielectric material, a polarization action occurs inside, and negative charges are collected on the weight body 211 side and positive on the weight body 212 side as shown in the figure. Charges will be collected. FIG. 18 is a side sectional view showing the state at this time (hatching indicating a section is omitted). Coulomb attractive force is applied between the weight body 211 and the stator electrode 111 and between the weight body 212 and the stator electrode 115, respectively.

  Subsequently, the voltage application between the stator electrode 111 and the stator electrode 115 is stopped. Instead, a predetermined voltage is applied between the stator electrode 112 and the stator electrode 116, and as shown in FIG. A positive charge is generated on the stator electrode 116 and a negative charge is generated on the stator electrode 116 side. When the charge distribution state on the stator electrode side changes in this way, the polarization state in the rotor 200 changes accordingly, but the charge transfer speed in the dielectric is slower than the charge transfer speed in the conductor. Therefore, the change in the polarization state in the rotor 200 cannot sufficiently follow the change in the charge distribution state on the stator electrode side. Therefore, as shown in FIG. 19, even after the electrode distribution on the stator electrode side changes, the polarization state on the rotor side remains as it was immediately before, and the Coulomb attractive force acts between the weight body 211 and the stator electrode 112. A Coulomb attractive force acts between the weight body 212 and the stator electrode 116. As a result, a rotational force directed in the direction of the arrow in the figure acts on the rotor 200, and the rotor 200 rotates to the position shown in FIG.

  Therefore, this time, the voltage application between the stator electrode 112 and the stator electrode 116 is stopped, and instead, a predetermined voltage is applied between the stator electrode 113 and the stator electrode 117 so that a positive charge is applied to the stator electrode 113 side. If a negative charge is generated on the stator electrode 117 side, a Coulomb attractive force acts between the weight body 211 and the stator electrode 113, and a Coulomb attractive force is generated between the weight body 212 and the stator electrode 117. Works. As a result, the rotor 200 is further subjected to a rotational force in the counterclockwise direction. In the same manner, if the charge distribution related to the stator electrodes 111-118 is moved counterclockwise, the rotor 200 continuously rotates counterclockwise accordingly.

  After all, if the AC voltage signals S1-S8 as shown in FIG. 21 are supplied from the voltage supply circuit 310 to the respective stator electrodes 111-118, the rotor 200 can be continuously rotated in the counterclockwise direction. It becomes possible. Of course, if the supplied AC voltage signal is changed, it can be rotated continuously in the clockwise direction, or it can be rotated in the reverse direction alternately repeating the clockwise movement and the counterclockwise movement. . However, in the structure shown in this embodiment, it is preferable that the rotor 200 is continuously rotated at a constant rotational speed. When the rotor 200 is continuously rotated at a constant speed, a fluid layer of air is formed on the lower surface of the rotor 200, and the rotor 200 rotates in a state where it floats above the substrate 100 as shown in FIG. It is possible to maintain a stable rotational motion. The reason why the rotor 200 floats in the rotating state is that the Coulomb attractive force acts on the stator electrode provided on the pedestal and the rotor 200 is on the air fluid layer formed with the rotation. is there.

  In this way, the rotor 200 performs a stable continuous rotational movement in a non-contact state with respect to the substrate 100, so that a vibration component accompanying rotation does not leak to the substrate side, and a reliable angular velocity detection becomes possible.

  In the above, the embodiment in which the rotor (weight body) is continuously rotated based on the principle of the induction motor has been described. However, in implementing the present invention, the principle for rotating the rotor is limited to the principle of the induction motor. Is not to be done. In short, any method may be used as long as the rotor (weight body) can be rotated without contacting the substrate. For example, it is possible to adopt a structure in which the rotor is rotated based on the principle of a variable capacity motor or an electret motor.

<<< §7. Principle of distance detection between weight body and substrate >>>
According to the basic principle of the angular velocity sensor according to the present invention, the Z-axis is detected by detecting the distance between the weight body and the substrate when the weight body in rotational motion passes above the X-axis or Y-axis. The Coriolis force Fcz acting in the direction is obtained, and the angular velocity ωx around the X axis or the angular velocity ωy around the Y axis is indirectly detected. Here, the principle of detecting the distance between the weight body and the substrate in the angular velocity sensor whose structure is described in §5 will be described.

  Consider a pair of capacitive elements formed by a fixed electrode pair formed on a substrate and a moving electrode formed on the lower surface of the weight body. For example, the side sectional view of FIG. 22 shows a state in which the moving electrode 231 formed on the lower surface of the weight body 211 is opposed to the pair of fixed electrodes 141A and 141B formed on the substrate 100. This state can be replaced with the equivalent circuit shown in the upper right of the figure. That is, the first capacitor element C1A is formed by the first fixed electrode 141A and a part of the moving electrode 231, and the second capacitor element C1B is formed by the second fixed electrode 141B and a part of the moving electrode 231. Yes. Moreover, since the moving electrode 231 is a single electrode, the pair of capacitive elements C1A and C1B are connected in series with the moving electrode 231 as an intermediate point.

Therefore, if the entire pair of capacitive elements C1A and C1B connected in series is regarded as one capacitive element C1, the capacitance value of the capacitive element C1 is C1, and the capacitance values of the individual capacitive elements C1A and C1B are When C1A and C1B, respectively,
1 / C1 = (1 / C1A) + (1 / C1B)
In particular, when C1A = C1B,
C1 = C1A / 2
It becomes.

  Similarly, regarding the moving electrode 232 formed on the lower surface of the weight body 212 and the pair of fixed electrodes 142A and 142B opposed to the moving electrode 232, the equivalent circuit as shown in the upper left of FIG. Will be. On the other hand, FIG. 23, which shows a cut surface along the Y-axis, shows an equivalent circuit of the moving electrode 233 formed on the lower surface of the weight body 213 and the pair of fixed electrodes 143A and 143B facing this, An equivalent circuit for the movable electrode 234 formed on the lower surface of the weight body 214 and a pair of fixed electrodes 144A and 144B facing the movable electrode 234 is shown, and the capacitive elements C3 and C4 are configured by these equivalent circuits. Will be.

  After all, when the rotor 200 is at the position shown in FIG. 24, the capacitive element C1 is formed below the weight body 211 located above the positive X axis, and the weight body located above the negative X axis. A capacitor element C2 is formed below 212, a capacitor element C3 is formed below the weight body 213 located above the positive Y axis, and below the weight body 214 located above the negative Y axis. The capacitor element C4 is formed.

  A pair of fixed electrodes (for example, fixed electrodes 141A and 141B) is provided on the substrate side, and a pair of capacitor elements (for example, capacitor elements C1A and C1B) connected in series is replaced by one capacitor element (for example, capacitor element C1). The reason for handling it is that wiring for the moving electrode provided on the rotor 200 side is difficult. For example, in the equivalent circuit shown in the upper right of FIG. 22, in order to directly measure the capacitance value of one capacitive element C1A itself, wiring for the fixed electrode 141A and wiring for the moving electrode 231 are required. However, the moving electrode 231 is an electrode that is rotated by the rotational motion of the rotor 200. As described above, the rotor 200 performs the rotational motion in a non-contact state with respect to the substrate 100. However, it is difficult to perform wiring. On the other hand, if the capacitance value of the entire pair of capacitive elements C1A and C1B connected in series is measured as the capacitance value of the capacitive element C1, wiring to the moving electrode 231 becomes unnecessary. That is, it is only necessary that the capacitance value between the first fixed electrode 141A and the second fixed electrode 141B can be measured electrically, so that wiring to the pair of fixed electrodes is performed. It ’s enough.

By the way, if the capacitance value C of the capacitive element constituted by a pair of electrodes is S, the electrode area is d, and the dielectric constant between the electrodes is ε,
C = ε · S / d
It is expressed by the following formula. Here, if the electrode area S and the dielectric constant ε are constant, the capacitance value C is inversely proportional to d, and if the capacitance value C can be measured, the electrode interval d can be obtained. . Therefore, in the equivalent circuits shown in FIGS. 22 and 23, the values of the capacitance values C1, C2, C3, and C4 are the distances between the weights 211, 212, 213, and 214 and the upper surface of the substrate 100, respectively. It becomes a related value. Eventually, if these capacitance values C1-C4 are detected by the detection circuit 320, this detection value becomes a value indicating the distance between the weight body and the substrate, and a value indicating the applied angular velocity.

  Next, the principle of actual angular velocity detection will be described with reference to FIG. Now, it is assumed that the rotor 200 is continuously rotating at a constant speed in a counterclockwise direction when viewed from above, based on the principle described in §6 above. At this time, assuming that an angular velocity ωx around the X axis as shown in the figure acts on the substrate 100, the Coriolis force Fcz in the positive direction of the Z axis is instant at the moment when the weight body 211 passes above the positive X axis. Act. At this time, the weight body 212 is passing above the negative X-axis, and the Coriolis force -Fcz in the Z-axis negative direction acts on this weight body 232. As a result, the entire rotor 200 is tilted as shown, and the electrode spacing of the capacitive element C1 is widened and the electrode spacing of the capacitive element C2 is narrowed as compared to the reference state in which no angular velocity acts. As a result, the capacitance value C1 decreases by ΔC1, and the capacitance value C2 increases by ΔC2. Therefore, taking the difference (ΔC1 + ΔC2) between the two capacitance values indicates the direction of the angular velocity ωx around the X axis where the sign of this difference acts, and the magnitude of this difference is an amount indicating the magnitude of the angular velocity ωx. . Note that ΔC1 and ΔC2 are not strictly equal, but at a practical level, they can be handled as ΔC1 = ΔC2 = ΔC, and the difference can be obtained as 2 · ΔC.

  FIG. 26 is a circuit diagram illustrating a specific circuit configuration example of the detection circuit 320. The capacitance values of the capacitive elements C1, C2, C3, and C4 are converted into voltage values V1 by C / V conversion circuits 321, 322, 323, and 324 having a function of converting the capacitance value C into the voltage value V, respectively. , V2, V3, and V4, the differential amplifier 325 calculates the difference between the voltage values V1 and V2, and the differential amplifier 326 calculates the difference between the voltage values V3 and V4. As described above, the voltage value difference (V1−V2) is output from the differential amplifier 325 as the output voltage Vωx indicating the angular velocity ωx around the X axis, and the voltage value difference (V3−V4) is the Y axis. It is output from the differential amplifier 326 as an output voltage Vωy indicating the surrounding angular velocity ωy.

  In the embodiment shown here, as shown in FIG. 24, since the rotor 200 having four weight bodies is used, each time the rotor 200 rotates 90 ° (each weight body passes on each axis). Each time, output voltages Vωx and Vωy indicating correct detection values are obtained. Further, when the rotor 70 having the annular structure 76 as shown in FIG. 9 is used, if a moving electrode is formed on the entire lower surface of the annular structure 76, a correct detection value is always output. It will be.

  The fixed electrodes 141A to 144A and 141B to 144B in the above-described embodiments are all arranged on the coordinate axes, but it is sufficient that the pair of fixed electrodes are arranged adjacent to the coordinate axes. 27 (the reference position of the weight body 211-214 is indicated by a broken line), the fixed electrodes 141C-144C, 141D-144D may be arranged with the coordinate axes interposed therebetween. In addition, the pair of adjacent fixed electrodes may be different in shape and size, but in order to simplify the detection circuit, it is necessary to make all the fixed electrodes have the same shape and the same size. preferable.

<<< §8. Another embodiment of the angular velocity sensor of the present invention >>>
The embodiment described in §5 is an angular velocity sensor having a structure suitable for continuously rotating the rotor. Here, an example of an angular velocity sensor having a structure suitable for rotating the rotor in a reverse rotation is used. Indicates. FIG. 28 is a side sectional view of such an embodiment, and FIG. 29 is a plan view showing the arrangement of the main components of this embodiment.

  The structure of the substrate 100 in this angular velocity sensor is exactly the same as the embodiment described in §5. The structure of the rotor 250 is substantially the same as the structure of the rotor 200 described in §5. However, the central member 260 is a cylindrical block, and is fixed to the upper end of the support 270 via the electrode 265. The support 270 is a cylindrical block, and the lower end is fixed on the substrate 100. Eventually, the rotor 250 is in a state where its central portion is fixed on the substrate 100 via the support 270. However, although the weight bodies 211-214 are indirectly connected to the substrate 100 via the arms 221-224 and the support body 270, they can be rotated in a rotating manner without contact with the substrate 100. It is in a state.

  In order to reversely rotate the rotor 250, it is necessary to use a support body 270 having a structure capable of generating a twist around the Z axis. In this embodiment, as described above, the support 270 is made of polysilicon, and by setting the size of the diameter to an appropriate dimension, it is possible to perform the reverse rotational movement with the required degree of freedom. ing.

  In this embodiment, in order to realize smoother rotational rotation, twelve stator electrodes are provided so that the angle difference is 30 °. FIG. 29 is a plan view showing the arrangement of these twelve stator electrodes E11 to E22 and the rotor 250. In order to reversely rotate the rotor 250, a predetermined AC voltage may be applied to each stator electrode.

  For example, as shown in FIG. 30, if a positive charge is generated in the stator electrode E11 and a negative charge is generated in the stator electrode E17, a negative charge is generated in the weight body 211 and a weight body 212 is formed on the rotor 250 side. A polarization phenomenon occurs in which positive charges are collected. Subsequently, when the stator electrodes E11 and E17 are returned to the neutral state and a positive charge is generated in the stator electrode E12 and a negative charge is generated in the stator electrode E18, the rotor 250 starts to rotate counterclockwise. Next, when the stator electrodes E12, E18 are returned to the neutral state and positive charges are generated in the stator electrode E11 and negative charges in the stator electrode E17, respectively, as shown in FIG. Flip around. Furthermore, if the stator electrodes E11 and E17 are returned to the neutral state, and a positive charge is generated in the stator electrode E22 and a negative charge is generated in the stator electrode E16, the rotor 250 continues to rotate further clockwise. Therefore, if the stator electrodes E22 and E16 are returned to the neutral state and positive charges are generated in the stator electrode E11 and negative charges in the stator electrode E17 as shown in FIG. 30, the rotational movement of the rotor 250 is counteracted. Flip clockwise.

  If the driving operation as described above is performed, the rotor 250 rotates counterclockwise in the first half cycle, and rotates clockwise in the second half cycle. As shown by the arrows in the figure, the rotor 250 rotates at a predetermined angle. Within this range, it will rotate and vibrate in reverse.

  However, when the rotor 250 performs such reverse rotational movement, the vibration component of the rotor propagates to the substrate 100 via the support 270, and there is an adverse effect that the vibration leaks to the apparatus housing. As described in. In addition, it has already been described that in order to prevent such vibration leakage, the reverse rotation motion may be performed in such a manner that the clockwise rotation and the counterclockwise rotation cancel each other. That is, in the case of a rotor having four weight bodies, as shown in FIG. 11 in the first half cycle and in FIG. 12 in the second half cycle, each weight body is rotated in a predetermined direction. You can do it.

  In order to apply such reverse rotation motion to the embodiment shown in FIG. 29, the following driving method may be implemented. First, as shown in FIG. 31, positive charges are generated on the stator electrodes E11 and E14, and negative charges are generated on the stator electrodes E17 and E20, respectively. Then, on the rotor 250 side, a polarization phenomenon occurs in which negative charges are collected in the weight bodies 211 and 213 and positive charges are collected in the weight bodies 212 and 214. Subsequently, when the stator electrodes E11, E14, E17, and E20 are returned to the neutral state and positive charges are generated in the stator electrodes E12 and E13 and negative charges are generated in the stator electrodes E18 and E19, respectively, as shown in FIG. The weight bodies 211 and 212 start to rotate counterclockwise, and the weight bodies 213 and 214 start to rotate clockwise. Next, when the stator electrodes E12, E13, E18, E19 are returned to the neutral state, and positive charges are generated in the stator electrodes E11, E14 and negative charges are generated in the stator electrodes E17, E20, respectively, as shown in FIG. The rotation direction of each weight body is reversed. Furthermore, if the stator electrodes E11, E14, E17, and E20 are returned to the neutral state and positive charges are generated on the stator electrodes E15 and E22 and negative charges are generated on the stator electrodes E16 and E21, respectively, as shown in FIG. The weight bodies 211 and 212 continue to move clockwise, and the weight bodies 213 and 214 continue to move counterclockwise. Therefore, when the stator electrodes E15, E16, E21, and E22 are returned to the neutral state and positive charges are generated in the stator electrodes E11 and E14 and negative charges are generated in the stator electrodes E17 and E20, respectively, as shown in FIG. The rotation direction of each weight body is reversed.

  When the driving operation as described above is performed, the two weight bodies constituting the rotor 250 rotate clockwise, and the remaining two weight bodies rotate counterclockwise. It is possible to prevent the adverse effect that the vibration leaks to the apparatus housing. If a resonance frequency specific to the rotor 250 is selected as the frequency (vibration frequency) of the reverse rotation motion, efficient driving is possible.

<<< §9. Basic principle of angular velocity detection around the Z axis >>
In the XYZ three-dimensional coordinate system, the angular velocity sensor described so far detects the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis by rotating the weight body on the substrate parallel to the XY plane. there were. Here, the principle of detecting the angular velocity ωz about the Z axis perpendicular to the substrate will be described.

  FIG. 34 is a perspective view showing the detection principle of the angular velocity ωz. The individual components shown in this figure are substantially the same as those shown in FIG. That is, the substrate 10 has a flat upper surface 11 and functions as an apparatus housing. The XYZ three-dimensional coordinate system is defined such that the upper surface 11 is included in the XY plane, and the Z axis extending upward from the origin O is an axis orthogonal to the upper surface 11. Here, energy is supplied from the energy supply means 30 to the weight body 20 having a predetermined mass so that the weight body 20 rotates along the orbit C in the figure with the Z axis as the rotation axis. To do. At this time, in a state where an external force such as angular velocity or acceleration does not act on this system, the weight body 20 maintains a constant distance h with respect to the upper surface 11 and a constant distance r with respect to the Z axis. While maintaining, energy supply from the energy supply means 30 is performed so as to rotate along the track C. Therefore, in a state where no external force is applied to the system (a state where the substrate 10 is stationary), the weight body 20 receives the energy supply from the energy supply means 30, and the weight body 20 is a plane represented by the equation Z = h. In this case, a rotational movement is made on a circular orbit C having a radius r.

  The angular velocity sensor further includes distance measuring means 80 that measures the distance (radius of rotational mobility) between the Z axis and the weight body 20 when the weight body 20 passes over the X axis. As described above, the weight body 20 always moves along the circular orbit C in a state where a force from outside the system does not act. In this state, the measured value by the distance measuring means 80 is always a constant radius. The value r is indicated.

However, when the entire system is rotating at an angular velocity ωz around the Z axis, in other words, when the angular velocity ωz is acting on the substrate 10, the Coriolis force based on this angular velocity is applied to the weight body 20. The movement of the weight body 20 deviates from the original circular orbit C. That is, as shown in FIG. 34, when the entire system rotates at an angular velocity ωz around the Z axis, the weight body 20 moving over the X axis with a velocity component Vy in the Y axis direction is used. , The Coriolis force Fcx in the X-axis direction (-Coriolis force in the X-axis direction -Fcx depending on the direction of the angular velocity ωz) acts.
Fcx = 2 ・ m ・ Vy ・ ωz
Is defined by the expression In the example shown in FIG. 34, due to the action of the Coriolis force Fcx, the trajectory of the weight body 20 moving in the Y-axis direction is distorted in the X-axis direction, and the weight at the time when it passes over the X-axis. The distance between the body 20 and the Z axis increases or decreases by Δr (depends on the direction of the angular velocity ωz), and becomes r ± Δr.

  If the mass m and the motion speed Vy of the weight body 20 are kept constant, the Coriolis force Fcx becomes a value proportional to the angular speed ωz, and eventually the initial circular orbit C when the weight body 20 passes above the X axis. The distance Δr from can be used as a value indicating the angular velocity ωz. Since r is constant, if the distance r + Δr between the weight body 20 and the Z axis can be measured, the value of the angular velocity ωz can be obtained. The angular velocity sensor shown in FIG. 34 has a function of detecting an angular velocity ωz around the Z axis based on such a principle. That is, the output of the distance measuring means 80 indicates the detected value of the angular velocity ωz.

  The above is the basic principle for detecting the angular velocity ωz. However, as described in §2, it is preferable to provide a function for canceling the influence of acceleration. In the configuration shown in FIG. 34, even if the trajectory of the weight body 20 is displaced by Δr in the X-axis direction, whether the displacement is caused by the Coriolis force Fcx or the force Fax based on the acceleration αx in the X-axis direction. It cannot be distinguished whether it is the cause or not.

  FIG. 35 shows a basic configuration of an angular velocity sensor having a function of canceling the acceleration component. In this sensor, a pair of weight bodies 21 and 22 are prepared, and each weight body is supplied with energy from the energy supply means 30 and moves on a circular orbit C having a radius r about the Z axis as a rotation axis. Rotating motion. However, as illustrated, when the first weight body 21 is located above the positive X axis, the first weight body 22 is located above the negative X axis. And the second weight body rotate in a state where the phases are shifted from each other by 180 °.

  The angular velocity sensor is provided with a pair of distance measuring means. That is, the positive on-axis distance measuring means 81 is configured such that when any weight body passes over the positive X-axis (the point where the first weight body 21 exists in FIG. 35), The negative on-axis distance measuring means 82 has a function of measuring the distance to the weight body that is passing, and any weight body is above the negative X-axis (the second weight in FIG. It has a function of measuring the distance between the Z-axis and the passing weight body at the time of passing through the point where the body 22 exists. In addition, a calculation means 83 for obtaining the sum of the distance measured by the positive X-axis distance measurement means 81 and the distance measured by the negative X-axis distance measurement means 82 is provided. Based on the output of the calculation means 83, the angular velocity ωz around the Z axis is detected.

  Next, the detection principle and the reason for canceling the acceleration component in this angular velocity sensor will be described. Now, as shown in FIG. 35, a pair of weight bodies 21 and 22 rotate on a circular orbit C included on a plane indicated by Z = h with a phase shifted by 180 ° from each other. Let us consider a state in which energy is supplied from the energy supply means 30 to be performed. In this state, as shown in the figure, the first weight body 21 passes over the positive X-axis with a velocity Vy in the Y-axis positive direction, and at the same time, the second weight body 22 passes over the negative X-axis. Through Y-axis negative direction speed -Vy. At this time, if an angular velocity ωz around the Z-axis is acting on the entire system, a Coriolis force Fcx in the X-axis positive direction is applied to the first weight body 21, and the first The weight body 21 deviates from the original circular orbit C to the outside (the direction away from the Z axis). On the other hand, a negative Coriolis force -Fcx in the negative direction of the X axis is applied to the second weight body 22, and the second weight body 22 deviates from the original circular orbit C to the outside.

  Now, it is assumed that the first weight body 21 and the second weight body 22 have exactly the same shape and the completely same mass. Here, since they are always rotating with a phase difference of 180 °, the absolute value of the speed of the rotating motion is the same. Therefore, the absolute value of the Coriolis force acting on both weights becomes the same, and it is assumed that the first weight 21 is moved outward from the circular orbit C by Δr and passes the position of the distance r + Δr from the Z axis. For example, the second weight body 22 also deviates from the circular orbit C by Δr and passes through the position of the distance r + Δr from the Z axis. Therefore, the calculation means 83 outputs 2r + 2 · Δr corresponding to the sum of these. If the output value 2r of the calculation means 83 in a state where no external force is applied is determined in advance as a reference value, the difference 2 · Δr from the reference value 2r becomes a value indicating the angular velocity ωz around the Z axis. When the direction of the applied angular velocity ωz is reversed, the direction of the Coriolis force is reversed, and the two weight bodies 21 and 22 are both disengaged from the original circular orbit C. In this case, the output from the calculation means 83 is 2r−2 · Δr. Therefore, the sign of the output signal obtained from the calculation means 83 indicates the direction of the angular velocity ωz, and the magnitude of the output signal indicates the magnitude of the angular velocity ωz.

  Here, consider a case in which acceleration acts on the entire system. Since the force Faz generated based on the acceleration αz in the Z-axis direction and the force Fay generated based on the acceleration αy in the Y-axis direction are both orthogonal to the Coriolis force Fcx in the X-axis direction, they interfere with this measurement system. Never do. However, since the force Fax generated based on the acceleration αx in the X-axis direction is in the same direction as the Coriolis force Fcx, the influence of interference must be considered. Actually, in the measurement system using the single weight body 20 shown in FIG. 34, the force Fax generated based on the acceleration αx interferes with the detected value of the angular velocity ωz. However, in the measurement system shown in FIG. 35 using a pair of weight bodies 21 and 22, this interference is cancelled. This is because when the force Fax generated based on the acceleration αx is applied, the two weight bodies 21 and 22 both generate the displacement Δx in the positive X-axis direction. The output increases by Δx, but the output of the negative X-axis distance measuring means 82 decreases by Δx. Therefore, the output of the calculation means 83 does not change due to the action of the acceleration αx.

  As described above, the acceleration component can be canceled by using the pair of weight bodies that perform the rotational motion in a state where the phases are shifted from each other by 180 °.

  In the above description, the positive X-axis distance measuring unit 81 and the negative X-axis distance measuring unit 82 are used to perform measurement when the weight body passes the X axis. The angular velocity ωz can be similarly detected even if measurement is performed when the weight body passes the Y axis using the positive Y-axis distance measuring means and the negative Y-axis distance measuring means. Needless to say, the angular velocity ωz can be measured not only on the X axis and the Y axis but also when the weight body passes on an arbitrary axis.

<<< §10. Specific Example of Three-dimensional Angular Velocity Sensor >>>
In §5, a specific example of the two-dimensional angular velocity sensor that can simultaneously detect the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis has been described. Here, by applying the principle described in §9 to this two-dimensional angular velocity sensor, the angular velocity ωx around the X axis, the angular velocity ωy around the Y axis, and the angular velocity ωz around the Z axis can be detected. An embodiment that implements the sensor will be described.

  FIG. 36 is a plan view of the three-dimensional angular velocity sensor, and FIG. 37 is a side sectional view showing a state in which the sensor is cut along the X axis. Since the structure of this three-dimensional angular velocity sensor is almost the same as the structure of the two-dimensional angular velocity sensor (see FIGS. 13 to 16) described in §5, only the difference between the two will be described here. Constituent elements common to both are indicated by the same reference numerals, and detailed description thereof is omitted.

  The first feature of this three-dimensional angular velocity sensor is that a rotor 400 having a structure having a stretchable part is used. As clearly shown in the plan view of FIG. 38, the rotor 400 has a structure in which four weight bodies 411 to 414 are connected to a central member 425 by four arms 421 to 424. Here, the four arms 421-424 have a zigzag structure as shown in the figure, and have elasticity. Therefore, when a force in a direction away from the center member 425 or a force in a direction approaching the center member 425 is applied to each weight body 411-414, the weight body can be displaced in the direction of the applied force. It is. The movement electrodes 431-434 are formed on the lower surfaces of the respective weight bodies 411-414 (the electrodes 433 and 434 are not shown), and the electrodes 435 are formed on the lower surface of the central member 425 as described above. The same as the two-dimensional angular velocity sensor.

  The second feature of the three-dimensional angular velocity sensor is that the shape and arrangement of the fixed electrodes on the substrate are slightly changed, and a new fixed electrode is added to detect the angular velocity ωz. FIG. 39 is a plan view showing a state where the stopper 400 of the angular velocity sensor shown in FIG. 36 is removed and the rotor 400 is removed. The fixed electrodes 145A to 148A and 145B to 148B arranged on the substrate 100 have the same function (that is, the angular velocity ωx around the X axis) as the fixed electrodes 141A to 144A and 141B to 144B shown in FIG. The fixed electrode fulfills the function of detecting the angular velocity ωy around the Y axis), but the area of each electrode is slightly smaller. The reason why the area is reduced in this way is that the four arms 421 to 424 constituting the rotor 400 have elasticity, so that the weight bodies 411 to 414 may be slightly displaced based on the elasticity of the arms. This is to prevent a change in the area of the capacitor element to be formed. On the other hand, the fixed electrodes 145C, 145D, 146C, and 146D are electrodes added to detect the angular velocity ωz around the Z axis. The detection circuit 330 calculates the capacitance value of a capacitive element configured by a total of 12 fixed electrodes arranged on the substrate 100 and a moving electrode formed on the rotor 400 side (the lower surface of each weight body). The detected value of the three-dimensional angular velocities ωx, ωy, ωz is output as an output of this circuit.

  The detection principle of the angular velocities ωx and ωy by this sensor is as already described in §7. Here, the detection principle of the angular velocity ωz will be described below. FIG. 40 is a plan view showing the capacitive element formed at the moment when the weight bodies 411 and 412 pass over the X-axis. Here, the constituent elements 431 and 432 indicated by broken-line rectangles indicate moving electrodes formed on the lower surfaces of the weight bodies 411 and 412, respectively, and the constituent element 420 is an intermediate with elasticity that connects both weight bodies. The member is shown. When the movable electrodes 431 and 432 as indicated by broken lines in the drawing are positioned above the fixed electrodes arranged on the substrate 100, capacitive elements are formed by the opposing electrodes, respectively. That is, the fixed electrodes 145A, 145B, 145C, 145D and the moving electrode 431 form the capacitive elements C1A, C1B, C5C, C5D, and the fixed electrodes 146A, 146B, 146C, 146D and the moving electrode 432 form the capacitive element C2A. , C2B, C6C, C6D are formed. Here, as described above, if the circuit shown in the left half of FIG. 26 is configured using the capacitive elements C1A, C1B, C2A, and C2B, the angular velocity ωx around the X axis can be detected. Here, it will be shown that the angular velocity ωz about the Z-axis can be detected using the capacitive elements C5C, C5D, C6C, and C6D.

  Consider a case where the rotor 400 is rotating at a constant speed in the state where no external force is applied to the sensor. In this steady state, at a moment when the weight bodies 411 and 412 pass over the X-axis, each fixed electrode and each moving electrode are fixed so that the positional relationship shown in the plan view of FIG. 40 is maintained. It is assumed that electrodes have been arranged. In this case, the hatched portion of each fixed electrode is the portion facing the moving electrode. In other words, the capacitive element is formed only in the hatched region. It should be noted that the fixed electrodes 145A, 145B, 146A, and 146B for detecting the angular velocity ωx are all hatched and the entire surface is involved in the formation of the capacitive element, whereas the fixed electrodes 145A, 145B, 146A, and 146B are used for detecting the angular velocity ωz. The fixed electrodes 145C, 145D, 146C, and 146D are all hatched only in the left half of the figure. In short, the fixed electrodes 145A, 145B, 146A, and 146B are formed at positions that are symmetric with respect to the Y axis, whereas the fixed electrodes 145C and 145D have a predetermined offset outward (in the direction away from the Z axis). The fixed electrodes 146C and 146D are formed at positions shifted by a predetermined offset amount inwardly (in the direction approaching the Z axis).

  Now, let us consider a case where an angular velocity ωz around the Z axis acts on the entire sensor. As already described in §9, when the angular velocity ωz is applied, Coriolis force along the radial direction of the circular motion is applied to each of the weight bodies 411-414. In the rotor 400, since each weight body is connected by the elastic intermediate member 420 (arms 421-424), the orbit of the weight body is outside (inside depending on the direction of the angular velocity ωz) by this Coriolis force. Will change. For example, if the trajectory of each weight body changes to the outside, the positional relationship between the fixed electrode and the moving electrode around the X axis is as shown in FIG. That is, the moving electrode 431 passing over the positive X-axis is displaced by a predetermined amount Δr in the positive X-axis direction by the action of the Coriolis force Fcx in the positive X-axis direction and passes over the negative X-axis. The moving electrode 432 in the middle is displaced by a predetermined amount Δr in the negative X-axis direction by the action of the Coriolis force −Fcx in the negative X-axis direction.

  When the position of the moving electrode is displaced in this way, the electrode area of the capacitive element constituted by the fixed electrodes 145A, 145B, 146A, 146B used for detecting the angular velocity ωx around the X axis (the area of the hatched portion in the figure) Does not change. In other words, the fixed electrodes 145A, 145B, 146A, and 146B always have the entire area as the moving electrode even if the trajectory of the weight body is displaced in the radial direction of the circular motion based on the expansion and contraction of the intermediate member 420. It will be arranged so as to face each other. For this reason, the angular velocity ωz around the Z axis does not interfere with the detection of the angular velocity ωx around the X axis. For the same reason, the angular velocity ωz around the Z axis does not interfere with the detection of the angular velocity ωy around the Y axis.

  On the other hand, there is a change in the electrode area (area of the hatched portion in the figure) of the capacitive element constituted by the fixed electrodes 145C, 145D, 146C, and 146D used for detecting the angular velocity ωz around the Z axis. Here, when the capacitive elements constituted by the fixed electrodes 145C, 145D, 146C, 146D and the moving electrodes 431, 432 are referred to as capacitive elements C5C, C5D, C6C, C6D, respectively, in the state shown in FIG. The capacitance values of the capacitive elements C5C and C5D increase as the electrode area increases, and the capacitance values of the capacitive elements C6C and C6D decrease as the electrode area decreases.

  By the way, although it is difficult to perform wiring for the rotor 400 that performs the rotational movement for the measurement of the capacitance value, each of the capacitances described above is formed by forming a pair of fixed electrodes. This value can be measured simply by wiring on the substrate 100 side. That is, if the entire pair of capacitive elements C5C and C5D connected in series is regarded as one capacitive element C5 and the entire pair of capacitive elements C6C and C6D connected in series is regarded as one capacitive element C6, The capacitance value can be measured as a capacitance value between the fixed electrodes 145C and 145D, and the capacitance value of the capacitive element C6 can be measured as a capacitance value between the fixed electrodes 146C and 146D.

  FIG. 42 is a circuit diagram showing a specific circuit configuration example for detecting the angular velocity ωz. Capacitance values of the capacitive elements C5 and C6 are converted into voltage values V5 and V6 by C / V conversion circuits 331 and 332 having a function of converting the capacitance value C into a voltage value V, respectively. The difference between the voltage values V5 and V6 is calculated and output by the amplifier 333. This output voltage indicates a difference (Fcx − (− Fcx)) in consideration of the sign of the applied Coriolis force, and is a value corresponding to the applied angular velocity ωz around the Z axis.

  Even in an environment where acceleration acts, the output voltage of the differential amplifier 333 is not affected by the acceleration. For example, when the acceleration αx in the X-axis direction acts, as shown in FIG. 43, both the moving electrodes 431 and 432 are displaced in the X-axis direction by the force Fax based on the acceleration αx, but the capacitive elements C5C, Since the electrode areas of C5D, C6C, and C6D all increase by the same amount, this increase is canceled by taking the difference by the differential amplifier 333. When the acceleration αy in the Y-axis direction is applied, the movable electrodes 431 and 432 are slightly displaced in the Y-axis direction, but there is no change in the electrode areas of the capacitive elements C5C, C5D, C6C, and C6D. There is no influence on the capacitance value of each capacitive element. Further, when the acceleration αz in the Z-axis direction is applied, the electrode intervals of the capacitive elements C5C, C5D, C6C, and C6D all increase or decrease by the same amount, so that the capacitance value also increases or decreases by the same amount. However, this difference is canceled by taking the difference by the differential amplifier 333.

  According to the basic principle shown in FIG. 35, in order to cancel the acceleration component, the sum of the output of the positive X-axis distance measuring means 81 and the output of the negative X-axis distance measuring means 82 is calculated by the calculating means 83. I was asking. On the other hand, in the embodiment shown here, the difference is obtained using the differential amplifier 333 in order to cancel the acceleration component. In this way, the former calculates the sum and the latter calculates the difference, but the two are equivalent in principle. In other words, the former calculates the sum related to the distance r, while the latter calculates the difference in the capacitance value C. Thus, the difference between the two is that the handling is different for the same phenomenon. Naturally, the increase / decrease in r and the increase / decrease in capacitance value C are different in behavior. For example, the circular motion radius of the weight body in the state of FIG. 40 is r, and the circular motion radius of the weight body in the state of FIG. 41 is r + Δr. According to the basic principle shown in FIG. 35, the angular velocity ωz about the Z-axis is obtained based on the sum of the distances from the central axis of the pair of weights whose phases are shifted by 180 °. Therefore, the sum of the distances was “2r” in the state of FIG. 40, but “2r + 2Δr” in the state of FIG. 41, and the angular velocity ωz at which “2Δr”, which is the variation of both states, acted. It becomes the value shown. However, according to the electrode arrangement in this embodiment, the increase / decrease in the capacitance value C does not necessarily coincide with the increase / decrease in the distance r. That is, as can be seen from FIG. 41, the capacitance values of the capacitive elements C5C and C5D increase as the distance r increases, whereas the capacitance values of the capacitive elements C6C and C6D decrease as the distance r increases. For this reason, in the circuit diagram shown in FIG. 42, the sign of the voltage value V6 corresponding to the capacitance value C6 is inverted by the differential amplifier 333. The “calculation for obtaining the difference between” is equivalent to the “calculation for obtaining the sum of the distances r”.

<<<< §11. Modification of 3D angular velocity sensor >>
44 is a side sectional view showing a modification of the three-dimensional angular velocity sensor described in §10. This sensor is obtained by replacing the rotor 400 of the sensor described in §10 with a rotor 450. The only difference between the rotor 400 and the rotor 450 is the structure of an arm having elasticity for connecting the weight bodies 411-414. That is, the arms 421-424 used in the rotor 400 have a zigzag structure when viewed from the top surface, but the rotor 450 of the modified example shown in FIG. 44 has a zigzag structure when viewed from the side surface. Arms 441 to 444 (arms 443 and 444 are not shown) are used.

  As the arm having elasticity, various other structures can be used. For example, a coil spring-like arm may be used. However, when a rotor is formed on a semiconductor substrate using a micromachining technique, manufacturing is easy if a plate spring having a zigzag structure is used as in the examples described above.

  FIG. 45 is a modified example in which the rotor in the three-dimensional angular velocity sensor described in §10 is configured to rotate and rotate. The rotor 500 has substantially the same structure as the rotor 450 shown in FIG. That is, the four weight bodies 511-514 are connected to the center member 560 by the arms 541-544 having a zigzag structure when viewed from the side (the weight bodies 513, 514, arms 543, 544 are Not shown). Moving electrodes 531-534 and 565 are formed on the lower surfaces of the weight body 511-514 and the central member 560 (the moving electrodes 533 and 534 are not shown), and the central member 560 is interposed via the electrode 565 and the support 570. Are fixed on the substrate 100. The support body 570 has a structure capable of generating a twist around the Z axis, and the rotor 500 can perform the reverse rotation motion as described in §8. The operation of this sensor is exactly the same as the operation of the sensor described in §10 except that the rotor 500 performs a reverse rotational motion, and detailed description thereof is omitted here.

  When the angular velocity sensor according to the present invention is attached to an object to be measured, the angular velocity ωx around the X axis and the angular velocity ωy around the Y axis acting on the object can be simultaneously detected, and the influence of the acceleration component can be detected. It is possible to obtain an accurate detection value that is not received. This angular velocity sensor can be manufactured using micromachining technology and semiconductor technology, and is suitable for miniaturization and mass production. Therefore, it is mounted on industrial machines, industrial robots, automobiles, airplanes, ships, etc., and can be widely used as sensors for recognizing motion states or performing feedback control for motions. It can also be used for control for correcting camera shake during shooting by the camera.

It is a perspective view which shows the basic composition of the angular velocity sensor for detecting angular velocity (omega) x and (omega) y around an X-axis and a Y-axis. It is a perspective view which shows the principle which Coriolis force acts when an angular velocity acts on the moving object. It is a perspective view explaining operation | movement of the angular velocity sensor shown in FIG. FIG. 4 is a perspective view showing a basic configuration of an angular velocity sensor for detecting angular velocities ωx and ωy about the X axis and the Y axis while canceling an acceleration component under an environment where acceleration acts. It is a perspective view explaining operation | movement of the angular velocity sensor shown in FIG. It is a perspective view which shows the modification of the angular velocity sensor shown in FIG. It is a top view which shows the specific structural example of the rotor part of the angular velocity sensor shown in FIG. FIG. 8 is a plan view showing a modification of the rotor shown in FIG. 7. FIG. 8 is a plan view showing still another modification of the rotor shown in FIG. 7. It is a top view which shows the operation | movement aspect which carries out reverse rotation motion (vibration motion) of the rotor shown in FIG. It is a top view which shows the 1st operation | movement aspect which carries out reverse rotation motion of the rotor shown in FIG. 7 by the method of canceling a rotational vibration component. It is a top view which shows the 2nd operation | movement aspect which carries out reverse rotation motion of the rotor shown in FIG. 7 by the method of canceling a rotational vibration component. It is a top view of the angular velocity sensor which concerns on the specific Example of this invention of the type which rotates a rotor continuously. It is a sectional side view which shows the state which cut | disconnected the angular velocity sensor shown in FIG. 13 along the X-axis. It is a top view which shows only the rotor of the angular velocity sensor shown in FIG. It is a top view which shows the state which removed the rotor from the angular velocity sensor shown in FIG. It is a top view for demonstrating operation | movement of the angular velocity sensor shown in FIG. It is a sectional side view which shows the cut surface along the X-axis for demonstrating operation | movement of the angular velocity sensor shown in FIG. It is a top view which shows the principle which rotates a rotor by giving a predetermined voltage to the stator of the angular velocity sensor shown in FIG. It is another top view which shows the principle which rotates a rotor by giving a predetermined voltage to the stator of the angular velocity sensor shown in FIG. It is a wave form diagram which shows the alternating voltage which should be given to the stator of the angular velocity sensor shown in FIG. FIG. 14 is a side sectional view showing a cut surface along the X axis in order to show a capacitive element constituted by a moving electrode formed on the rotor side of the angular velocity sensor shown in FIG. 13 and a fixed electrode formed on the stator side. FIG. 14 is a side cross-sectional view showing a cut surface along the Y axis in order to show a capacitive element composed of a moving electrode formed on the rotor side of the angular velocity sensor shown in FIG. 13 and a fixed electrode formed on the stator side. It is a top view which shows the capacitive element comprised by the moving electrode formed in the rotor side of the angular velocity sensor shown in FIG. 13, and the fixed electrode formed in the stator side. FIG. 14 is a side cross-sectional view showing a cut surface along the X axis when an angular velocity ωx around the X axis acts during rotation of the rotor in the angular velocity sensor shown in FIG. 13. It is a circuit diagram which shows the detection circuit used about the angular velocity sensor shown in FIG. It is a top view which shows another example of arrangement | positioning of the fixed electrode used for the angular velocity sensor shown in FIG. It is a sectional side view which shows the cut surface along the X-axis of the angular velocity sensor which concerns on the specific Example of this invention of the type which carries out reverse rotation motion (vibration motion) of a rotor. It is a top view which shows arrangement | positioning of the main components of the angular velocity sensor shown in FIG. It is a top view which shows the operation | movement aspect which carries out reverse rotation motion of the rotor in the angular velocity sensor shown in FIG. FIG. 29 is a plan view showing a first operation mode in which the rotor is rotated in a reverse rotation manner by a method of canceling the rotational vibration component in the angular velocity sensor shown in FIG. 28. It is a top view which shows the 2nd operation | movement aspect which reversely rotationally moves a rotor by the method of canceling a rotational vibration component in the angular velocity sensor shown in FIG. It is a top view which shows the 3rd operation | movement aspect which reversely rotationally moves a rotor by the method of canceling a rotational vibration component in the angular velocity sensor shown in FIG. It is a perspective view which shows the basic composition of the angular velocity sensor for detecting angular velocity (omega) z around Z-axis. It is a perspective view which shows the basic composition of the angular velocity sensor for detecting angular velocity (omega) z around a Z-axis, canceling an acceleration component in the environment where an acceleration acts. It is a top view which shows the specific Example of the three-dimensional angular velocity sensor which can detect angular velocity (omega) x, (omega) y, and (omega) z around three axes. FIG. 37 is a side sectional view showing a state where the angular velocity sensor shown in FIG. 36 is cut along the X axis. It is a top view which shows only the rotor of the angular velocity sensor shown in FIG. It is a top view which shows the state which removed the rotor from the angular velocity sensor shown in FIG. It is a top view which shows the capacitive element formed when external force is not acting on the angular velocity sensor shown in FIG. FIG. 37 is a plan view showing a capacitive element formed when an angular velocity ωz about the Z axis is acting on the angular velocity sensor shown in FIG. 36. It is a circuit diagram which shows a part of detection circuit used about the angular velocity sensor shown in FIG. FIG. 37 is a plan view showing a capacitive element formed when an acceleration αx in the X-axis direction is acting on the angular velocity sensor shown in FIG. 36. FIG. 37 is a side sectional view showing a modified example of the angular velocity sensor shown in FIG. 36 in which the structure of the rotor is changed. FIG. 37 is a side cross-sectional view showing a modification in which the angular velocity sensor shown in FIG.

Explanation of symbols

10: Substrate 11: Upper surface of substrate 20: Weight bodies 21 to 28: Weight body 30: Energy supply means 40: X-axis upward distance measuring means 41: Positive X-axis upward distance measuring means 42: Negative X-axis upward Distance measuring means 43: first difference calculating means 50: Y-axis upward distance measuring means 51: positive Y-axis upward distance measuring means 52: negative Y-axis upward distance measuring means 53: second difference calculating means 60: rotor 61-64: arm 65: center member 68: rotor 70: rotors 71-74: arm 75: center member 76: annular structure 80: distance measuring means 81: positive on-axis distance measuring means 82: negative X-axis Upper distance measuring means 83: computing means 100: substrate 101: silicon substrate 102: silicon oxide film 103: upper surface 111-118 of substrate: stator electrodes 121-128: pedestal 130: pivot 131: stoppers 141A-14 D: Fixed electrodes 142A to 142D: Fixed electrodes 143A to 143D: Fixed electrodes 144A to 144D: Fixed electrodes 145A to 145D: Fixed electrodes 146A to 146D: Fixed electrodes 147A, 147B: Fixed electrodes 148A, 148B: Fixed electrodes 200: Rotor 211 To 214: weight bodies 221 to 224: arm 225: center members 231 to 234: moving electrode 235: electrode 250: rotor 260: center member 265: electrode 270: support 310: voltage supply circuit 320: detection circuits 321 to 324 : C / V conversion circuit 325, 326: Differential amplifier 330: Detection circuit 331, 332: C / V conversion circuit 333: Differential amplifier 400: Rotor 411-414: Arm 420: Intermediate members 421-424: Arm 425: Central members 431-434: moving electrode 435: electrode 441- 44: Arm 450: Rotor 500: Rotors 511 to 514: Weight bodies 531 to 534: Moving electrodes 541 to 544: Arm 560: Center member 565: Moving electrode 570: Support body A, B: Position C: Circular orbit C1 C4: Capacitance elements C1A to C4B: Capacitance elements C5C, C5D, C6C, C6D: Capacitance elements E11 to E22: Stator electrode Fax: Force based on acceleration in the X-axis direction Fcx: Coriolis force in the X-axis direction Fcz: Z-axis direction Coriolis force h: distance Δh: distance difference M1 to M4: mass point O: origin of coordinate system P: point r: distance S1 to S8: AC voltage signal T: time V, V1 to V6: voltage Vx, Vy: each coordinate axis Directional velocity Vωx, Vωy, Vωz: Voltages W1, W2 corresponding to angular velocity around each coordinate axis: Axes X, Y, Z: Each coordinate axis on the three-dimensional coordinate system θ: Angles ωx, ωy, ωz: Around each coordinate axis Angular velocity

Claims (13)

A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
A conductive moving electrode formed on the lower surface of the annular structure;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
A pair of fixed electrodes each composed of a pair of electrodes arranged adjacent to each other on the X axis of the upper surface of the substrate or adjacent to each other so as to sandwich the X axis of the upper surface of the substrate;
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
Each of the pair of electrodes constituting the fixed electrode pair is disposed at a position that can be opposed to the moving electrode that is moving above,
A detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the fixed electrode pair is further provided, and an angular velocity around the X axis acting on the substrate is determined using the detection value of the detection circuit. An angular velocity sensor characterized by detecting. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
A conductive moving electrode formed on the lower surface of the annular structure;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
A first fixed electrode pair comprising a pair of electrodes arranged adjacent to each other on the positive X axis of the upper surface of the substrate or adjacent to each other so as to sandwich the positive X axis of the upper surface of the substrate; ,
A second fixed electrode pair comprising a pair of electrodes arranged adjacent to each other on the negative X axis of the upper surface of the substrate or adjacent to each other so as to sandwich the negative X axis of the upper surface of the substrate; ,
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
The pair of electrodes constituting the first fixed electrode pair and the pair of electrodes constituting the second fixed electrode pair are both arranged at positions that can be opposed to the moving electrode moving upward,
A first detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the first fixed electrode pair;
A second detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the second fixed electrode pair;
Difference calculating means for obtaining a difference between a detection value by the first detection circuit and a detection value by the second detection circuit;
And detecting an angular velocity around the X-axis acting on the substrate using the difference obtained by the difference calculation means. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
A conductive moving electrode formed on the lower surface of the annular structure;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
An X-axis fixed electrode pair comprising a pair of electrodes arranged adjacent to each other on the X-axis of the upper surface of the substrate or adjacent to each other so as to sandwich the X-axis of the upper surface of the substrate;
A pair of fixed Y-axis electrodes each composed of a pair of electrodes arranged adjacent to each other on the Y-axis of the upper surface of the substrate or adjacent to each other so as to sandwich the Y-axis of the upper surface of the substrate;
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
The pair of electrodes constituting the X-axis fixed electrode pair and the pair of electrodes constituting the Y-axis fixed electrode pair are both arranged at positions that can be opposed to the moving electrode moving upward,
An X-axis detection circuit that electrically detects a capacitance value between a pair of electrodes constituting the X-axis fixed electrode pair;
A Y-axis detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the Y-axis fixed electrode pair;
Further comprising
Using the detection value of the X-axis detection circuit, the angular velocity around the X-axis acting on the substrate is detected, and using the detection value of the Y-axis detection circuit, the Y-axis rotation acting on the substrate An angular velocity sensor for detecting an angular velocity of the sensor. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
A conductive moving electrode formed on the lower surface of the annular structure;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
A first fixed electrode pair comprising a pair of electrodes arranged adjacent to each other on the positive X axis of the upper surface of the substrate or adjacent to each other so as to sandwich the positive X axis of the upper surface of the substrate; ,
A second fixed electrode pair comprising a pair of electrodes arranged adjacent to each other on the negative X axis of the upper surface of the substrate or adjacent to each other so as to sandwich the negative X axis of the upper surface of the substrate; ,
A third fixed electrode pair comprising a pair of electrodes arranged adjacent to each other on the positive Y axis on the upper surface of the substrate or adjacent to each other so as to sandwich the positive Y axis on the upper surface of the substrate; ,
A fourth fixed electrode pair composed of a pair of electrodes arranged adjacent to each other on the negative Y axis of the upper surface of the substrate or adjacent to each other so as to sandwich the negative Y axis of the upper surface of the substrate; ,
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
A pair of electrodes constituting the first fixed electrode pair, a pair of electrodes constituting the second fixed electrode pair, a pair of electrodes constituting the third fixed electrode pair, and the fourth fixed electrode pair Each of the pair of electrodes that are configured is disposed at a position that can be opposed to the moving electrode that is moving above,
A first detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the first fixed electrode pair;
A second detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the second fixed electrode pair;
A third detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the third fixed electrode pair;
A fourth detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the fourth fixed electrode pair;
First difference calculation means for obtaining a difference between a detection value by the first detection circuit and a detection value by the second detection circuit;
Second difference calculation means for obtaining a difference between a detection value by the third detection circuit and a detection value by the fourth detection circuit;
And detecting the angular velocity around the X-axis acting on the substrate using the difference obtained by the first difference calculation means, and using the difference obtained by the second difference calculation means, An angular velocity sensor for detecting an angular velocity around the Y-axis acting on the substrate. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
Distance measuring means for measuring a distance between a predetermined point on the X axis and a predetermined portion of the annular structure moving above the X axis;
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
Using the distance measured by the distance measuring means, and having a function of detecting an angular velocity around the X-axis acting on the substrate;
The distance measuring unit is adjacent to the conductive moving electrode formed on the lower surface of the annular structure and the X axis of the upper surface of the substrate, or adjacent to the X axis of the upper surface of the substrate. In either case, the fixed electrode pair consisting of a pair of electrodes arranged at positions that can be opposed to the moving electrode moving upward, and the capacitance value between the pair of electrodes constituting the fixed electrode pair are electrically An angular velocity sensor, wherein the capacitance value detected by the detection circuit is used as a distance measurement value. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
First distance measuring means for measuring a distance between a predetermined point on the positive X axis and a predetermined portion of the annular structure moving above the positive point;
A second distance measuring means for measuring a distance between a predetermined point on the negative X axis and a predetermined portion of the annular structure moving above the negative point;
Difference calculating means for obtaining a difference between a measured value by the first distance measuring means and a measured value by the second distance measuring means;
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
Using the difference obtained by the difference calculation means, it has a function of detecting an angular velocity around the X axis acting on the substrate,
The first distance measuring means includes a conductive moving electrode formed on the lower surface of the annular structure and a positive X axis on the upper surface of the substrate adjacent to each other on the positive X axis. A pair of fixed electrodes composed of a pair of electrodes disposed adjacent to each other so as to sandwich the shaft and facing each of the moving electrodes moving upward, and a pair of electrodes constituting the pair of fixed electrodes And a detection circuit that electrically detects the capacitance value of the sensor, and the capacitance value detected by the detection circuit is used as a distance measurement value.
The second distance measuring means includes a conductive moving electrode formed on the lower surface of the annular structure and a negative X axis on the upper surface of the substrate adjacent to each other on the negative X axis of the upper surface of the substrate. A pair of fixed electrodes composed of a pair of electrodes disposed adjacent to each other so as to sandwich the shaft and facing each of the moving electrodes moving upward, and a pair of electrodes constituting the pair of fixed electrodes And a detection circuit that electrically detects a capacitance value of the angular velocity sensor, wherein the capacitance value detected by the detection circuit is used as a distance measurement value. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
X-axis upward distance measuring means for measuring a distance between a predetermined point on the X-axis and a predetermined portion of the annular structure that moves above the X-axis,
Y-axis upward distance measuring means for measuring a distance between a predetermined point on the Y-axis and a predetermined part of the annular structure that moves above the Y-axis;
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
Using the distance measured by the X-axis upward distance measuring means, the angular velocity around the X-axis acting on the substrate is detected, and using the distance measured by the Y-axis upward distance measuring means, the substrate Has a function of detecting the angular velocity around the Y-axis acting on
The X-axis upward distance measuring means is arranged such that the conductive moving electrode formed on the lower surface of the annular structure and the X-axis of the upper surface of the substrate are adjacent to each other or sandwich the X-axis of the upper surface of the substrate. Adjacent to each other, a fixed electrode pair consisting of a pair of electrodes arranged at positions that can be opposed to the moving electrode that is moving upward, and a capacitance between the pair of electrodes constituting the fixed electrode pair A detection circuit that electrically detects a value, and a capacitance value detected by the detection circuit is used as a distance measurement value,
The Y-axis upward distance measuring means is arranged such that the conductive moving electrode formed on the lower surface of the annular structure and the Y-axis on the upper surface of the substrate are adjacent to each other or sandwich the Y-axis on the upper surface of the substrate. Adjacent to each other, a fixed electrode pair consisting of a pair of electrodes arranged at positions that can be opposed to the moving electrode that is moving upward, and a capacitance between the pair of electrodes constituting the fixed electrode pair An angular velocity sensor comprising: a detection circuit that electrically detects a value; and a capacitance value detected by the detection circuit as a measured value of distance. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A rotor that performs a rotational motion in a non-contact state with respect to the substrate upper surface with a Z axis orthogonal to the substrate upper surface as a rotation axis, and an outer portion forming an annular structure with the Z axis as a central axis;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
First distance measuring means for measuring a distance between a predetermined point on the positive X axis and a predetermined portion of the annular structure moving above the positive point;
A second distance measuring means for measuring a distance between a predetermined point on the negative X axis and a predetermined portion of the annular structure moving above the negative point;
A third distance measuring means for measuring a distance between a predetermined point on the positive Y axis and a predetermined portion of the annular structure moving above the positive point;
A fourth distance measuring means for measuring a distance between a predetermined point on the negative Y axis and a predetermined portion of the annular structure moving above the negative point;
First difference calculation means for obtaining a difference between a measurement value obtained by the first distance measurement means and a measurement value obtained by the second distance measurement means;
Second difference calculation means for obtaining a difference between a measurement value obtained by the third distance measurement means and a measurement value obtained by the fourth distance measurement means;
With
The rotor is disposed on the substrate so as to be able to rotate with a predetermined degree of freedom with respect to the substrate.
An angular velocity around the X-axis acting on the substrate is detected using the difference obtained by the first difference calculation means, and the difference obtained by the second difference calculation means is used to act on the substrate. Has a function to detect the angular velocity around the Y axis,
The first distance measuring means includes a conductive moving electrode formed on the lower surface of the annular structure and a positive X axis on the upper surface of the substrate adjacent to each other on the positive X axis. A pair of fixed electrodes composed of a pair of electrodes disposed adjacent to each other so as to sandwich the shaft and facing each of the moving electrodes moving upward, and a pair of electrodes constituting the pair of fixed electrodes And a detection circuit that electrically detects the capacitance value of the sensor, and the capacitance value detected by the detection circuit is used as a distance measurement value.
The second distance measuring means includes a conductive moving electrode formed on the lower surface of the annular structure and a negative X axis on the upper surface of the substrate adjacent to each other on the negative X axis of the upper surface of the substrate. A pair of fixed electrodes composed of a pair of electrodes disposed adjacent to each other so as to sandwich the shaft and facing each of the moving electrodes moving upward, and a pair of electrodes constituting the pair of fixed electrodes And a detection circuit that electrically detects the capacitance value of the sensor, and the capacitance value detected by the detection circuit is used as a distance measurement value.
The third distance measuring means includes a conductive moving electrode formed on the lower surface of the annular structure and a positive Y axis on the upper surface of the substrate adjacent to each other, or a positive Y on the upper surface of the substrate. A pair of fixed electrodes composed of a pair of electrodes disposed adjacent to each other so as to sandwich the shaft and facing each of the moving electrodes moving upward, and a pair of electrodes constituting the pair of fixed electrodes And a detection circuit that electrically detects the capacitance value of the sensor, and the capacitance value detected by the detection circuit is used as a distance measurement value.
The fourth distance measuring means includes a conductive moving electrode formed on a lower surface of the annular structure and a negative Y axis on the upper surface of the substrate adjacent to each other on the negative Y axis. A pair of fixed electrodes composed of a pair of electrodes disposed adjacent to each other so as to sandwich the shaft and facing each of the moving electrodes moving upward, and a pair of electrodes constituting the pair of fixed electrodes And a detection circuit that electrically detects a capacitance value of the angular velocity sensor, wherein the capacitance value detected by the detection circuit is used as a distance measurement value. In the angular velocity sensor according to any one of claims 1 to 8,
An angular velocity sensor characterized in that the rotor is made of silicon, and the moving electrode formed on the lower surface of the annular structure of the rotor is made of silicon doped with high-concentration impurities. In the angular velocity sensor according to any one of claims 1 to 9,
Providing a pivot fixed to the upper surface of the substrate so as to extend along the Z axis;
The rotor is constituted by an outer part forming an annular structure and an inner part attached so as to be rotatable with respect to the pivot axis and movable in the Z-axis direction with a predetermined degree of freedom. An angular velocity sensor. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A disk-shaped rotor disposed so as to be tiltable with a predetermined degree of freedom with respect to the substrate, with the Z axis orthogonal to the substrate upper surface as a rotation axis;
A moving electrode formed on the lower surface of the rotor;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
A pair of fixed electrodes each composed of a pair of electrodes arranged adjacent to each other on the X axis of the upper surface of the substrate or adjacent to each other so as to sandwich the X axis of the upper surface of the substrate;
With
Each of the pair of electrodes constituting the fixed electrode pair is disposed at a position that can be opposed to the moving electrode that is moving above,
A detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the fixed electrode pair is further provided, and an angular velocity around the X axis acting on the substrate is determined using the detection value of the detection circuit. An angular velocity sensor characterized by detecting. A substrate having an upper surface along an XY plane in an XYZ three-dimensional coordinate system;
A disk-shaped rotor disposed so as to be tiltable with a predetermined degree of freedom with respect to the substrate, with the Z axis orthogonal to the substrate upper surface as a rotation axis;
A moving electrode formed on the lower surface of the rotor;
Energy supply means for supplying energy so that the rotor rotates in a non-contact state with respect to the upper surface of the substrate, with the Z axis serving as a rotation axis in a state where no external force acts;
An X-axis fixed electrode pair comprising a pair of electrodes arranged adjacent to each other on the X-axis of the upper surface of the substrate or adjacent to each other so as to sandwich the X-axis of the upper surface of the substrate;
A pair of fixed Y-axis electrodes each composed of a pair of electrodes arranged adjacent to each other on the Y-axis of the upper surface of the substrate or adjacent to each other so as to sandwich the Y-axis of the upper surface of the substrate;
With
The pair of electrodes constituting the X-axis fixed electrode pair and the pair of electrodes constituting the Y-axis fixed electrode pair are both arranged at positions that can be opposed to the moving electrode moving upward,
A first detection circuit for electrically detecting a capacitance value between a pair of electrodes constituting the X-axis fixed electrode pair; and a capacitance between the pair of electrodes constituting the Y-axis fixed electrode pair. A second detection circuit that electrically detects a value, and using the detection value of the first detection circuit, detects an angular velocity around the X-axis acting on the substrate; and An angular velocity sensor that detects an angular velocity around the Y-axis acting on the substrate by using a detection value of a detection circuit. The angular velocity sensor according to claim 11 or 12,
An angular velocity sensor characterized in that the rotor is constituted by a silicon disk.