JP3301403B2 - Vibrating gyro - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyroscope, and more particularly, to a vibrating gyroscope used for detecting an angular velocity for preventing camera shake.

[0002]

2. Description of the Related Art FIG. 14 is a perspective view showing an example of a conventional vibrating gyroscope. Vibrating gyroscope 1 includes, for example, positive triangular <br/> pillar shaped vibrating body 2. Piezoelectric elements 3a, 3b, 3c are formed on three side surfaces of the vibrating body 2, respectively. In order to use the vibrating gyroscope 1, an oscillation circuit 4 is connected between the piezoelectric elements 3a and 3b and the piezoelectric element 3c, for example, as shown in FIG. Further, the piezoelectric elements 3a, 3b
Are connected to the detection circuit 5. The detection circuit 5 includes a differential circuit, a synchronous detection circuit, a smoothing circuit, a DC amplifier circuit, and the like.

In the vibrating gyroscope 1, the output signal of the piezoelectric element 3c is fed back to the oscillation circuit 4. In the oscillation circuit 4, the feedback signal is amplified and the phase is adjusted to form an excitation signal. The excitation signal thus obtained is provided to the piezoelectric elements 3a and 3b. Thereby, the vibrating body 2 bends and vibrates in a direction orthogonal to the surface on which the piezoelectric element 3c is formed. In this state, the piezoelectric elements 3a, 3
The bending state of b is the same, and its output signal is also the same. Therefore, no signal is output from the differential circuit of the detection circuit 5. When the vibrating body 2 rotates around the axis of the vibrating body 2 in a state of bending vibration, the vibration direction of the vibrating body 2 changes due to Coriolis force. Therefore, the piezoelectric elements 3a,
A difference occurs in the signal output from 3b, and the signal is output from the differential circuit. This signal is detected by a synchronous detection circuit, smoothed by a smoothing circuit, and amplified by a DC amplifier circuit. Therefore, by measuring the output signal of the detection circuit 5,
The rotational angular velocity can be detected.

Further, as the vibrating gyroscope 1, as shown in FIG. 16, a vibrating body 2 may be manufactured by joining two piezoelectric substrates 6a and 6b. These piezoelectric substrates 6a,
6b are polarized in opposite directions, as indicated by the arrows in FIG. In this case, two electrodes 7a and 7b extending in the longitudinal direction are formed on one surface side of the vibrating body 2, and the electrode 8 is formed on the entire surface on the other surface side of the vibrating body. Even in such a vibrating gyroscope 1, the angular velocity can be detected by the circuit shown in FIG.

[0005]

However, these vibrating gyros can only detect the angular velocity about the axis of the vibrating body, and can detect only the angular velocity in one direction. Therefore, in order to detect angular velocities in two directions, it is necessary to use two vibrating gyroscopes, and two oscillation circuits are required to excite these vibrating gyroscopes. Such an oscillation circuit is expensive, and the cost for detecting angular velocities in a plurality of directions increases.

Therefore, the main object of the present invention is to provide:
An object of the present invention is to provide a vibrating gyroscope capable of detecting angular velocities in two directions with one element.

[0007]

According to the present invention, there are provided a center member, four vibrating arms formed radially outward from the center member so that adjacent members on the same plane are orthogonal to each other, Between the vibrating arms
Four weight arms formed radially outward from the center member, and the vibrating arm bends and vibrates on the same plane, and the Coriolis force of the vibration of the vibrating arm is used.
And an excitation detecting means for outputting a signal corresponding to the displacement caused by the vibration gyro. In such a vibrating gyroscope, the vibrating arm and the weight arm are formed of the piezoelectric substrate, and the electrodes are formed on the vibrating arm, so that the excitation detection means can be formed by the electrode and the piezoelectric substrate. Further, the central member, the arm for vibration and the arm for weight may be integrally formed by a metal plate, and the excitation detecting means may be formed by a piezoelectric element formed on the metal plate. Furthermore, the central member is formed of a piezoelectric substrate, the central portion
The material , the vibrating arm and the weight arm may be integrally formed. Further, when the vibration arm and the weight arm are formed of a piezoelectric substrate, the vibration arm and the weight arm can be arranged on a substrate used as a central member.

[0008] The four vibration arms vibrate on the plane on which they are arranged, centering on the central member, by the excitation detecting means. At this time, since the adjacent vibration arms are arranged on the radiation so as to be orthogonal to each other, a force acts in a direction of rotating as a whole by the vibration of the vibration arms. However, since the weight arm is formed between the vibration arms, the weight is applied in a direction opposite to the vibration direction of the vibration arm so that the force acts in a direction in which the rotational force due to the vibration of the vibration arm is offset. The arm vibrates. When the arm rotates about the axis of the vibration arm, the vibration direction of the vibration arm changes due to the Coriolis force, and a signal corresponding to the Coriolis force is output from the excitation detecting means. Here, since the four vibration arms are arranged orthogonally,
Signals corresponding to angular velocities in two orthogonal directions can be obtained. In this vibrating gyroscope, the excitation detecting means is formed by the piezoelectric body and the electrode formed thereon, but the vibration arm itself may be formed by a piezoelectric body, or a piezoelectric element different from the vibration arm may be used. May be used as excitation detection means. That is, the excitation detection means is formed by a structure capable of generating a bending vibration in the vibration arm by the excitation signal and outputting a signal corresponding to the displacement of the vibration arm.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0010]

FIG. 1 is a perspective view showing an example of a vibrating gyroscope according to the present invention. The vibrating gyroscope 10 includes a central member 12 having, for example, a square planar shape. On the same plane including the central member 12, the four vibration arms 14a,
14b, 14c and 14d are formed. Vibration arm 1
4a to 14d are each formed in a rectangular parallelepiped shape, and are arranged such that adjacent ones are orthogonal to each other. In addition, 4
Weight arms 16 a, 16 b, 16 c, each having a square planar shape, are provided between the two vibration arms 14 a to 14 d.
16d are formed. The weight arms 16a to 16d also
It is arranged radially outward from the central member 12.
The central member 12, the vibrating arms 14a to 14d, and the weight arms 16a to 16d are integrally formed.

Central member 12, vibrating arms 14a to 14
The d and the weight arms 16a to 16d are formed, for example, by joining two piezoelectric substrates 18 and 20 together. These piezoelectric substrates 18 and 20 are polarized, for example, from the facing surface side to the joining surface side, as shown by arrows in FIG. For example, electrodes are formed on the entire surface of the piezoelectric substrate 18, and the electrodes are divided by the grooves 22, 24, and 26.

The groove 22 is formed at the center in the width direction of the vibrating arms 14a and 14c so as to extend from the vibrating arm 14a toward the vibrating arm 14c. The groove 24 is formed so as to extend from the vibration arm 14b toward the vibration arm 14d at the center in the width direction of the vibration arms 14b and 14d. Further, the groove 26 is provided inside the central member 12 with the vibrating arm 1.
4a to 14d are formed to be divided. The electrodes 28a and 28b on the vibrating arm 14a separated by these grooves 22, 24 and 26, and the vibrating arm 14
b, electrodes 32a and 32b on vibrating arm 14c, and electrode 34 on vibrating arm 14d.
a and 34b are used for signal input / output. Further, over the entire surface of the piezoelectric substrate 20, as shown in FIG.
An electrode 36 is formed. Such a vibration arm 14a
Excitation detecting means is constituted by the piezoelectric substrate and the electrodes forming １４14d. Although the electrodes are also formed on the piezoelectric substrate 18 constituting the weight arms 16a to 16d by adopting a manufacturing method described later,
This electrode is not related to the operation of the vibrating gyroscope 10.

In order to manufacture such a vibrating gyroscope 10, for example, as shown in FIG.
8 and 20 are joined together, a plurality of original plates 38 each having electrodes formed on both sides are stacked, and a cut 40 is formed with a dicer or the like on a solidified body with wax or the like. This cut 40
Thereby, the vibrating arms 14a to 14d and the weight arms 16a to 16d are formed. And cut 4
0 is formed in the electrode on one surface of each original plate 38 on which the grooves 2 are formed.
By forming 2, 24, 26, the vibration gyro 1
0 is created. The electrodes on the other portions may be removed by etching or the like while leaving the electrodes on the vibrating arms 14a to 14d. At this time, the vibrating arms 14a to 14a
Etching is performed so that the electrode on 14d is divided into two. In this case, it is not necessary to form the grooves 22, 24, 26. In other words, if there are electrodes for signal input / output on the vibrating arms 14a to 14d, it is not necessary to form electrodes for other portions.

In order to use the vibrating gyroscope 10,
A circuit as shown in FIG. 4 is used. In FIG. 4, the electrodes 28a, 28b, 30a, 30 of the vibrating arms 14a to 14d are shown for easy understanding of the connection relationship.
b, 32a, 32b, 34a, 34b are shown side by side. The entire surface electrode 36 formed on the piezoelectric substrate 20 is connected to a reference potential.

Electrodes 28 of vibrating arms 14a to 14d
b, 30b, 32b, and 34b have resistors 42,
44, 46 and 48 are connected. These resistors 42, 4
4, 46, 48 and electrodes 28a, 30a, 32a, 34a
The oscillation circuit 50 is connected between the two. Further, the electrodes 28b and 32b of the vibrating arms 14a and 14c are connected to a differential circuit 52, and the differential circuit 52 is connected to a synchronous detection circuit 54.
Connected to. Further, the synchronous detection circuit 54 includes a smoothing circuit 5.
6 and the smoothing circuit 56 is connected to the DC amplifier circuit 58. Similarly, the electrodes 3 of the vibrating arms 14b and 14d
0b and 34b are connected to another differential circuit 60, and the differential circuit 60 is connected to the synchronous detection circuit 62. Further, the synchronous detection circuit 62 is connected to the smoothing circuit 64,
Is connected to a DC amplifier circuit 66.

Electrodes 28 of vibrating arms 14a to 14d
Output signals from a, 30a, 32a, and 34a are fed back to the oscillation circuit 50. The returned signal is output from the oscillation circuit 50.
And the phase is adjusted to form an excitation signal. This excitation signal is applied to the electrodes 28b, 30b, 32b, 34b of the vibrating arms 14a to 14d. As a result, the vibrating arms 14a to 14d flex and vibrate on the same plane as indicated by the solid and dotted arrows in FIG. At this time, the vibrating arms 14a to 14d
Vibrate so as to be in the same rotational direction, so that a force acts on the vibrating gyro 10 in the rotational direction. However,
The weight arms 16a to 16d vibrate in such a direction as to offset the rotational force caused by the vibrations of the vibration arms 14a to 14d, and the rotational force does not act on the vibration gyro 10 as a whole.

At this time, since the bending states of the vibrating arms 14a to 14d are the same, the electrodes 28b, 30b, 32
The signals output from b and 34b are the same. Therefore, no signal is output from the differential circuits 52 and 60.
Therefore, it is understood that no angular velocity is applied to the vibrating gyroscope 10. In such a vibration state, the vibration
The gyro 10 includes a vibration arm 14a and a vibration arm 1
When rotated about an axis passing through 4c, Coriolis force acts in a direction orthogonal to the vibration direction of the vibration arms 14a and 14c as shown in FIG. At this time, since the Coriolis force does not act on the other vibration arms 14b and 14d, the vibration directions of these vibration arms 14b and 14d do not change.

As shown by solid and dotted arrows in FIG. 6, Coriolis forces in opposite directions act on the vibrating arms 14a and 14c. Therefore, the vibration arms 14a, 1
4c is displaced in the opposite direction, and a signal corresponding to the displacement is output from the electrodes 28b and 32b. Therefore, the electrode 28
The signals output from b and 32b include signals of opposite polarity corresponding to Coriolis force. When such a signal is input to the differential circuit 52, the differential circuit 52 outputs
A large signal corresponding to the Coriolis force is output.

The output signal of the differential circuit 52 is detected by a synchronous detection circuit 54 in synchronization with the signal of the oscillation circuit 50. As a result, only the positive portion or only the negative portion of the output signal of the differential circuit 52, or a signal obtained by inverting either the positive or negative signal is detected. The detected signal is smoothed by a smoothing circuit 56 and further amplified by a DC amplifier circuit 58. Since the output signal of the differential circuit 52 has a level corresponding to the Coriolis force, the level of the output signal of the DC amplifier circuit 58 also corresponds to the Coriolis force. The size can be detected. Further, when the direction of the angular velocity applied to the angular velocity sensor 10 is reverse, the polarity of the signal detected by the synchronous detection circuit 54 is reversed. Therefore, the polarity of the output signal of the DC amplifier circuit 58 is also reversed, and depending on the polarity of the output signal of the DC amplifier circuit 58,
The direction of the angular velocity can be detected.

Further, the vibrating gyroscope 10 includes the vibrating arm 1
When the rotation about the axis passing through the vibration arm 14b and the vibration arm 14d is performed, the vibration arm 14 is rotated in the same manner as when the rotation is performed about the axis passing through the vibration arms 14a and 14c.
Coriolis force acts on b and 14d. At this time, no Coriolis force acts on the vibrating arms 14a and 14c. Therefore, the differential arm 60, the synchronous detection circuit 62, the smoothing circuit 64, and the DC amplifier circuit 66 allow the vibration arm 14b,
An angular velocity about the axis passing through 14d can be detected.

As described above, in this vibration gyro 10,
Angular velocity about two orthogonal axes can be detected. Moreover, only one oscillating circuit 50 is required to excite the fundamental vibrations to the vibration arms 14a to 14d, and the cost can be reduced as compared with the conventional method using two oscillating circuits.

The vibration gyro 10 shown in FIG.
Although the center member 12, the vibrating arms 14a to 14d, and the weight arms 16a to 16d are formed integrally, they may be formed individually. In this case, for example, as shown in FIG.
Vibrating arms 14a to 14d individually formed on
And weight arms 16a to 16d. Here, as the base 70, it is preferable to use the same material as the vibration arm and the weight arm. The base 70
Electrodes 3 of vibration arms 14a to 14d adhered to
In order to use 6 as a common electrode, for example, a base 7
An electrode may be formed on the entire surface or the upper surface of the base 70, and the electrode formed on the base 70 may be connected to a reference potential.

In order to manufacture such a vibrating gyroscope 10, as shown in FIG. 8, an original plate 38 in which electrodes are formed on both surfaces by bonding piezoelectric substrates 18 and 20 is adhered on a base 70. You. Then, using a dicer or the like, the vibrating arms 14a to 14d and the weight arms 16a to 16d
The original plate 38 is cut so that is separated. Further, by forming grooves in the electrodes formed on the upper surfaces of the vibration arms 14a to 14d, each vibration arm 14a
Two electrodes for excitation detection are formed on .about.14d.
In FIG. 7, since each part is formed by cutting the original plate 38, the central part 38a of the original plate 38 remains. However, even without this central part 38a, the angular velocity is detected by the vibrating gyroscope 10. can do.

The center member 12, the vibrating arm 14a
When the weight arms 14a to 14d and the weight arms 16a to 16d are integrally formed of a piezoelectric material, the whole may be formed in a disk shape as shown in FIG. Further, as shown in FIG. 10, the vibrating arms 14a to 14d and the weight arms 16a
To 16d may have the same shape. In this case, the vibrating arms 14a to 14d and the weight arms 16a
-16d are arranged at an angle of 45 °. Further, as shown in FIG. 11, for example, fan-shaped vibrating arms 14a to 14d and weight arms 16a to 16d may be bonded on a circular base 70. Also in this case, similarly to the vibrating gyroscope shown in FIG. 10, the vibrating arms 14a to 14d and the weight arms 16a to 16d are arranged at an angle of 45 °.

Further, the center member 12, the vibration arm 14
a to 14d and the weight arms 16a to 16d may be integrally formed of a metal plate or the like. In this case, FIG.
As shown in FIG. 2, on the vibrating arms 14a to 14d,
The piezoelectric elements 72a, 72b, 72c, 72d are formed. In each of the piezoelectric elements 72a to 72d, an electrode divided into two in the width direction is formed on one surface of one piezoelectric substrate polarized in the thickness direction, and an electrode is formed on the entire surface on the other surface. It is a thing. The whole surface electrodes formed on the other surface side of the piezoelectric substrate are connected to the vibrating arms 14a to 14a.
4d. In such a vibrating gyroscope 10 as well, the entire surface electrodes of the piezoelectric elements 72a to 72d are connected to the reference potential, and the divided electrodes are used for excitation detection, whereby the bending arms 14a to 14d are flexibly vibrated in the same plane. Can be generated, and the angular velocity can be detected using the circuit shown in FIG.

The center member 12, the vibrating arm 14a
When the weight arms 14a to 14d and the weight arms 16a to 16d are integrally formed of a metal plate, as shown in FIG.
The piezoelectric element 74 may be bonded to the center member 12. This piezoelectric element 74 joins two square piezoelectric substrates,
An electrode divided into eight is formed on one surface side, and an electrode is formed on the entire surface on the other surface side. 8
Each of the vibrating arms 1 of the divided electrodes
4a to 14d, electrodes 76a,
76b, electrodes 78a and 78b, electrodes 80a and 80b, and electrodes 82a and 82b
Used for excitation detection for a to 14d. Also in such a vibrating gyroscope 10, the vibrating arms 14a to 14d can be vibrated on the same plane by using the electrodes shown in FIG. 4 by using the electrodes corresponding to the vibrating arms 14a to 14d. (2) It is possible to detect an angular velocity about two axes.

As shown in FIGS. 12 and 13, in a vibrating gyroscope 10 using a metal plate or the like, the vibrating arms 14a to 14d and the weight arms 16a to 16d
May be formed in a disk shape as shown in FIGS.

[0028]

According to the present invention, one vibrating gyroscope can detect angular velocities about axes in two directions. Further, the vibration gyro can be excited by one oscillation circuit, and the cost can be reduced as compared with the conventional method using two vibration gyros.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a vibrating gyroscope according to the present invention.

FIG. 2 is a perspective view showing the other surface side of the vibrating gyroscope shown in FIG.

FIG. 3 is an illustrative view showing a method of manufacturing the vibrating gyroscope shown in FIG. 1;

FIG. 4 is a block diagram showing a circuit for using the vibrating gyroscope shown in FIG. 1;

FIG. 5 is an illustrative view showing an FEM analysis of a movement when the vibration gyro shown in FIG. 1 is performing a basic vibration.

FIG. 6 is an illustrative view showing an FEM analysis of a motion when an angular velocity is applied to the vibrating gyroscope shown in FIG. 1;

FIG. 7 is a plan view showing another example of the vibrating gyroscope of the present invention.

FIG. 8 is an illustrative view showing a method of manufacturing the vibrating gyroscope shown in FIG. 7;

FIG. 9 is a perspective view showing a modified example of the vibrating gyroscope shown in FIG.

FIG. 10 is a perspective view showing another modified example of the vibrating gyroscope shown in FIG.

FIG. 11 is a plan view showing a modified example of the vibrating gyroscope shown in FIG.

FIG. 12 is a perspective view showing another example of the vibrating gyroscope of the present invention.

FIG. 13 is a perspective view showing a modified example of the vibrating gyroscope shown in FIG.

FIG. 14 is a perspective view showing an example of a conventional vibrating gyroscope.

FIG. 15 is a block diagram showing a circuit for using the conventional vibrating gyroscope shown in FIG.

FIG. 16 is a perspective view showing another example of a conventional vibration gyro.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration gyroscope 12 Central member 14a-14d Vibration arm 16a-16d Weight arm 18, 20 Piezoelectric substrate 28a, 28b Electrode 30a, 30b Electrode 32a, 32b Electrode 34a, 34b Electrode 36 Electrode 70 Base 72a-72d Piezoelectric element 74 Piezoelectric element

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-218914 (JP, A) JP-A 8-271256 (JP, A) JP-A 7-113642 (JP, A) JP-A 2-218914 129513 (JP, A) JP-A-10-160476 (JP, A) JP-A-10-267664 (JP, A) JP-A-9-196682 (JP, A) JP-A-7-113644 (JP, A) JP-A-2000-249555 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 19/56 G01P 9/04

Claims (5)

(57) [Claims] 1. A central member, four vibrating arms are formed radially from the as adjacent ones are orthogonal to each other the central member outward in the same plane, the center between the vibrating arm Four weight arms formed radially outward from the member , and the vibrating arm bends and vibrates on the same plane, and the vibration of the vibrating arm is caused by Coriolis force.
A vibrating gyroscope including excitation detection means for outputting a signal corresponding to displacement . 2. The vibrating arm and the weight arm are formed of a piezoelectric substrate, and an electrode is formed on the vibrating arm to form the excitation detecting means by the electrode and the piezoelectric substrate. The vibrating gyroscope according to claim 1. 3. The center member, the vibrating arm and the weight arm are integrally formed of a metal plate, and the excitation detecting means is formed by a piezoelectric element formed on the metal plate. The vibrating gyroscope according to 1. 4. The central member is formed of a piezoelectric substrate,
The vibrating gyroscope according to claim 2, wherein the center member , the vibrating arm, and the weight arm are integrally formed. 5. The vibrating gyroscope according to claim 2, wherein said vibrating arm and said weight arm are arranged on a substrate used as said central member.