JP3440812B2 - 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 gyro, and more particularly to a vibrating gyro used for preventing camera shake of a video camera, a car navigation system, a pointing device and the like.

[0002]

2. Description of the Related Art As a conventional vibrating gyro, the present applicant has applied for a vibrating gyro having a structure disclosed in Japanese Patent Laid-Open No. 7-332988. This will be described with reference to the drawings.

A vibrating gyro 100 as a first conventional example shown in FIG. 5 includes a vibrator 101. In the oscillator 101, a first piezoelectric substrate 103 polarized in the thickness direction and a second piezoelectric substrate 104 polarized in the opposite direction to the first piezoelectric substrate 103 are bonded via an intermediate electrode 105. It is constructed as a unit. Then, on the one main surface of the first piezoelectric substrate 103, along the longitudinal direction of the first piezoelectric substrate 103, the two divided electrodes 106a,
106b is provided, and the common electrode 107 is formed on the entire one main surface of the second piezoelectric substrate 104.
1 is configured. The vibrator 101 of the vibrating gyro 100 is provided between the first piezoelectric substrate 103 and the second piezoelectric substrate 104, that is, in the intermediate electrode 105.
A linear support member 108 is provided and supported at a position corresponding to a node point of the vibrator 101.

Another conventional vibration gyro is disclosed in Japanese Patent Application Laid-Open No. 9-250931.
This will be described with reference to the drawings. A vibration gyro 110 according to a second conventional example shown in FIG. 6 includes a vibrator 111. In the vibrator 111, a first piezoelectric substrate 113 polarized in the thickness direction and a second piezoelectric substrate 114 polarized in the opposite direction to the first piezoelectric substrate 113 are bonded via a metal plate 115. It is constructed as a unit. Then, the first piezoelectric substrate 113 is provided on one main surface of the first piezoelectric substrate 113.
Along the longitudinal direction of the second piezoelectric substrate 114, electrodes 116a and 116b divided into two are provided so as to be separated from each other, and one main surface of the second piezoelectric substrate 114 is provided along the longitudinal direction of the second piezoelectric substrate 114. Then, the divided electrodes 117a and 117b are provided so as to be separated from each other, and the vibrator 111 is configured. Then, the vibrator 1 of this vibrating gyro 110
11, a plate-shaped support portion 118 is integrally formed at a position corresponding to the node point of the vibrator 111 on the metal plate 115, and a base (not shown) is provided on the tip side of the support member 118. ) Is integrally formed, and the vibrator 111 is supported via the support member 118 and the mounting portion 119.

The vibrators 101 and 111 of these vibrating gyros 100 and 110 generate bending vibrations in the x-axis direction shown in FIGS. 6 and 7 when a drive signal is applied. When a rotational angular velocity around the z-axis direction is applied to the oscillators 101 and 111, a Coriolis force corresponding to the rotational angular velocity is generated in the y-axis direction and the oscillators 101 and 111 are generated.
Generates bending vibration due to Coriolis force in the y-axis direction.

[0006]

However, the conventional vibrating gyroscope described above has the following problems.

That is, in the vibrating gyro, it is ideal that the support member is point-connected to a true node point existing inside the vibrator. However, that is physically impossible. Therefore, as shown in the first conventional example and the second conventional example, the supporting member is in contact with and connected to the piezoelectric substrate even around the true node point, which inevitably causes vibration of the vibrator. This is a factor that leaks to the outside through the support member and disturbs the vibration stability.

Further, in the vibrating gyro, the oscillator is y
When a flexural vibration due to Coriolis force is generated in the axial direction, a pendulum motion with the node point as the center is performed near the node point of the oscillator. As a result, a force due to the Coriolis force parallel to the longitudinal direction of the vibrator, that is, parallel to the z-axis direction is applied to the support member arranged near the node point of the vibrator.

At this time, in the second conventional example, since the supporting member formed so as to project from the side surface of the vibrator is plate-shaped, it is caused by the Coriolis force parallel to the z-axis direction applied to the supporting member. It has a structure with a large binding force against the force. Therefore, the amplitude of the vibrator is restricted, the obtained Coriolis signal becomes small, and the detection sensitivity also decreases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a vibration gyro which is less likely to cause vibration leakage of the vibrator and has high Coriolis force detection sensitivity.

[0011]

In order to achieve the above object, the present invention provides a first piezoelectric substrate which is polarized in the thickness direction, and a first piezoelectric substrate which is laminated on the first piezoelectric substrate and is polarized in the thickness direction. A second piezoelectric substrate, a metal plate as an intermediate electrode layer provided between the first piezoelectric substrate and the second piezoelectric substrate, and a first piezoelectric substrate formed on one main surface of the first piezoelectric substrate. A driving unit for driving the vibrator in the thickness direction, which includes a columnar vibrator including one band-shaped electrode and a second band-shaped electrode formed on one main surface of the second piezoelectric substrate; A vibrating gyroscope comprising: a detecting unit that detects displacement generated by bending of the vibrator, wherein the metal plate is located near a node point of the vibrator.
A metal plate body portion formed in a narrow width Te, the width of the metal plate body portion
Parallel to each main surface of the first and second piezoelectric substrates from the narrow portion
A support member extending in the width direction of the vibrator while having a surface is integrally provided, and
Thickness of the metal plate in the portion sandwiched by the second piezoelectric substrate
Thin, or metal near the node point of the oscillator
First and second piezoelectric bases at portions sandwiching the plate
By scraping off the other main surface of the plate , the metal plate is not in contact with the first piezoelectric substrate and the second piezoelectric substrate in the vicinity of the node points of the vibrator.

The support member for the metal plate is the
It is characterized in that it extends in the width direction of the vibrator from the vicinity of the dot point, and is bent to have a surface that is substantially orthogonal to the longitudinal direction of the vibrator at the tip .

[0013]

[0014]

As a result, since the supporting member does not directly contact the piezoelectric substrate, the function of the supporting member for restraining the vibration of the vibrator can be reduced, and the amount of bending of the vibrator becomes sufficiently large. The signal becomes larger and the sensitivity as a vibration gyro improves.

Further, by bending the support member so as to have a surface orthogonal to the longitudinal direction of the vibrator, the force in the direction parallel to the vibrator longitudinal direction due to the Coriolis force applied to the support member is applied to the vibrator longitudinal direction. Since the structure is absorbed (buffered) by the plane orthogonal to the direction, the amplitude of the oscillator is not constrained, and thus the obtained Coriolis signal becomes large and the detection sensitivity is also improved.

Further, for a metal plate integrally having a supporting member, the width near the intersection of the metal plate main body and the supporting member is compared with the width of the portion other than the intersection, and the width near the intersection is narrowed. By doing so, since the point support at the node points of the vibrator can be configured in a pseudo manner, the vibration leakage from the vibrator to the support member can be reduced, and the flexural vibration of the vibrator is not hindered, and the vibration gyro The sensitivity of is improved.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2, 10
Is a vibrating gyro and includes a vibrator 11. Oscillator 11
Is a first piezoelectric substrate 13 made of piezoelectric ceramics polarized in the thickness direction, that is, the x-axis direction in the drawing,
A second piezoelectric substrate 14 made of piezoelectric ceramics polarized in the opposite direction to the first piezoelectric substrate 13 is bonded and integrated via a metal plate 15 as an intermediate electrode layer made of a constant elastic metal such as elinvar. Is composed of On the one main surface of the first piezoelectric substrate 13, two first strip electrodes 16a are provided so as to be separated from each other in the longitudinal direction of the first piezoelectric substrate 13, that is, along the y-axis direction in the drawing. , 16b are provided, and a full-surface electrode 17 is provided on almost the entire other main surface. A second strip electrode 18 is provided on almost the entire one main surface of the second piezoelectric substrate 14, and a full-surface electrode 19 is provided on almost the entire other main surface. These electrodes are formed by using a thick film forming technique such as printing or a thin film forming technique such as vapor deposition, plating or sputtering.
The entire surface electrode 17 of the first piezoelectric substrate 13 and the entire surface electrode 19 of the second piezoelectric substrate 14 are connected to the metal plate 1
The vibrator 11 is configured by being attached to the member 5 with an adhesive made of an epoxy resin or the like.

Here, the metal plate 15 is the metal plate body 15
a is integrally formed with four support members 15b provided so as to project from the side surface corresponding to the node point of the vibrator 11, and is formed by punching a single metal plate by press working. It With this vibrating gyro 10,
The metal plate 15 and the first piezoelectric substrate 13 and the second piezoelectric substrate 14 are structured so as to be in non-contact with each other in the vicinity of the node points of the vibrator 11, that is, separated from each other. Here, the metal plate 15 integrally has a supporting member 15b so as to project from the vicinity of the node point, and thus the metal plate 15 and the vibrator 11 are not in contact with each other near the node point. As a result, the support member 15b also has a non-contact relationship with the vibrator 11.

The metal plate 15 and the first piezoelectric substrate 1
As means for making the third piezoelectric substrate 14 and the second piezoelectric substrate 14 non-contact with each other, for example, in the present embodiment, a portion of the metal plate 15 corresponding to the vicinity of the node point of the vibrator 11 is thinly processed. It As a method of thinning a part of the metal plate 15, there are a method of etching both sides of a thinned portion of the metal plate 15 or a press working from only both sides of the portion. Further, as another means for bringing the metal plate 15 and the first piezoelectric substrate 13 and the second piezoelectric substrate 14 into non-contact with each other, although not particularly shown, the first piezoelectric substrate 13 and the second piezoelectric substrate 13 are not shown. It is also configured by scraping off a portion of the other principal surface of the piezoelectric substrate corresponding to the vicinity of the node point of the vibrator 11.

As described above, in the metal plate 15 integrally including the metal plate body 15a and the supporting member 15b, the metal plate 15, the first piezoelectric substrate 13 and the second piezoelectric substrate 14 vibrate. The support member 15b is also in non-contact relationship with the vibrator 11 by being non-contact near the node point of the child 11. As a result, the support member 15b becomes
The function of restraining the vibration of the vibrator 11 is reduced, the vibration of the vibrator 11 is stabilized, and the change of the amplitude of the vibrator 11 due to the change of the external environment such as humidity and temperature becomes small. The vibration gyro 10 that can obtain a stable detection signal can be configured. In addition, the support member 15b and the first piezoelectric substrate 1
3 and the second piezoelectric substrate 14 are not in contact with each other,
Vibration is less likely to leak to the outside through the support member 15b,
Therefore, the amplitude of the vibrator 11 is increased, and the sensitivity of the vibration gyro 10 is also improved.

Further, the vibrating gyro 10 is composed of the metal plate 1
The support member 15b of No. 5 is bent so as to have a surface 15b ′ that is substantially orthogonal to the longitudinal direction of the vibrator 11, that is, the z-axis direction. Then, the vibration gyro 10 is attached to the attachment substrate 21 via the four support members 15b (surface 15b ').

The vibrator 11 generates bending vibration in the x-axis direction in response to a drive signal from an oscillation circuit 30 described later. Then, when a rotational angular velocity around the z-axis direction is applied to the oscillator 11, a Coriolis force corresponding to the rotational angular velocity is generated in the y-axis direction, and the oscillator 11 generates bending vibration due to the Coriolis force in the y-axis direction. . Then, near the node point of the oscillator 11, a pendulum motion centering on the node point is performed. As a result, the support member 1 disposed near the node point of the vibrator 11
A force due to the Coriolis force parallel to the longitudinal direction of the vibrator 11, that is, parallel to the z-axis direction is applied to 5b. Then, the support member 15b has a surface 15b ′ that is substantially orthogonal to the longitudinal direction of the vibrator 11, that is, the z-axis direction.
Since it is bent so as to have
The force due to the Coriolis force applied to b is the surface 15b ′.
Since the structure is such that it is absorbed (buffered), the amplitude of the vibrator 11 is not restricted, and therefore the obtained Coriolis signal is increased and the detection sensitivity is also improved.

Further, in this vibrating gyroscope 10, the metal plate 15 is compared with a portion near the intersection between the metal plate body 15a and the supporting member 15b and a portion other than the vicinity of the intersection to compare the metal plate 1 with the metal plate 1.
The width of 5 is narrower near the intersection. The intersection of the metal plate body 15a and the support member 15b coincides with the true node point of the vibrator 11. With this configuration, since the point support at the true node point of the vibrator 11 can be configured in a pseudo manner, vibration leakage from the vibrator 11 to the support member 15b can be reduced and the vibrator 11 can be bent. The sensitivity of the vibration gyro 10 is improved without disturbing the vibration.

Next, the operation of the vibrating gyro 10 will be described with reference to FIG. In order to apply a drive signal to the vibrator 11, the output end of the oscillation circuit 30 as a driving unit is connected to the second strip electrode 18 of the vibrator 11. Then, the two first strip electrodes 16a and 16b of the vibrator 11 are provided.
Is connected to the input end of the oscillation circuit 30 via two IV conversion circuits 32a and 32b. Also the two first
The strip-shaped electrodes 16a, 16b of the detection circuit 40 serving as the detection means have two input terminals of the IV conversion circuits 32a, 32b.
It is connected via b. Further, the metal plate 1 of the vibrator 11
5 is connected to the reference potential point.

The oscillating circuit 30 includes a synthesizing circuit 301 and an AGC.
It is composed of a circuit 302 and a phase circuit 303. Two first strip electrodes 16a and 16b of the vibrator 11
The feedback signal output from the I-V conversion circuit 32a, 3
It is converted into a voltage in 2b and is input to the combining circuit 301 to be combined. The output signal of the combining circuit 301 is AGC
It is input to the circuit 302 and the amplitude is kept constant. AG
The output signal of the C circuit 302 is input to the phase circuit 303,
The output signal of the oscillation circuit 30, that is, the drive voltage of the drive signal and the oscillation point of the drive signal are adjusted. Then, the output signal of the phase circuit 303 is the output signal of the oscillation circuit 30,
It is input to the second strip electrode 18 of the vibrator 11.

The detection circuit 40 is composed of a differential amplification circuit 401, a synchronous detection circuit 402, a smoothing circuit 403, and a DC amplification circuit 404. The detection signals output from the two first strip electrodes 16a and 16b of the vibrator 11 are converted into voltages by the IV conversion circuits 32a and 32b,
It is input to the differential amplifier circuit 401, and the difference between the output signals of the two first strip electrodes 16a and 16b is output by the differential amplifier circuit 401. The output signal of the differential amplifier circuit 401 is input to the synchronous detection circuit 402 and detected. At this time, the detection position (detection timing) is determined according to the signal output from the combining circuit 301. Synchronous detection circuit 40
The output signal 2 is input to the smoothing circuit 403 and smoothed. The output signal of the smoothing circuit 403 is input to the DC amplification circuit 404, is DC amplified, and is output as the detection signal of the detection circuit 40.

In this vibrating gyro 10, the oscillation circuit 30
A drive signal such as a sine wave signal output from the oscillator 1
It is applied between the second strip-shaped electrode 18 and the intermediate electrode 15. This drive signal causes the second piezoelectric substrate 14 to flexurally vibrate. Therefore, the vibrator 11 flexurally vibrates in the direction (x-axis direction) orthogonal to the main surface thereof. In this state,
When a rotational angular velocity about the central axis is applied to the oscillator 11, a signal due to the Coriolis force corresponding to the rotational angular velocity is generated between the two first strip electrodes 16a and 16b. A signal caused by the Coriolis force is detected from the two first strip electrodes 16a and 16b via the detection circuit 40.

In the vibrating gyroscope of the above embodiment, the support member 15b of the metal plate 15 is the vibrator 11
It is configured to have a surface orthogonal to the longitudinal direction (z-axis direction) of the vibrator 11 by bending toward the upper side of the support member 15. For example, as shown in FIG.
b may be bent toward the lower side of the vibrator 11.
Note that the other configuration is the vibration gyro 1 shown in FIGS.
Since it is the same as 0, the same numbers are assigned and the description thereof is omitted.

[0030]

As described above, in the vibrating gyroscope according to the present invention, since the supporting member does not directly contact the piezoelectric substrate, the function of the supporting member to restrain the vibration of the vibrator can be reduced, and the vibrator can be reduced. The amount of bending is sufficiently large, the obtained Coriolis signal is large, and the sensitivity as a vibration gyro is improved.

Further, by bending the support member so as to have a surface orthogonal to the longitudinal direction of the oscillator, the force in the direction parallel to the oscillator longitudinal direction due to the Coriolis force applied to the support member is applied to the oscillator. Since the structure is such that it is absorbed (buffered) by the plane orthogonal to the longitudinal direction, the amplitude of the oscillator is not restricted, and therefore the obtained Coriolis signal becomes large and the detection sensitivity is also improved.

Further, a metal plate integrally having a supporting member is compared with the vicinity of the intersection of the metal plate body and the supporting member and the portion of the metal plate other than near the intersection, and the vicinity of the intersection is narrowed. By doing so, since the point support at the node points of the vibrator can be configured in a pseudo manner, the vibration leakage from the vibrator to the support member can be reduced, and the flexural vibration of the vibrator is not hindered, and the vibration gyro The sensitivity of is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a vibrating gyroscope according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the structure of the vibrating gyroscope according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an operation circuit of the vibrating gyroscope according to the first embodiment of the present invention.

FIG. 4 is an exploded perspective view showing another example of the structure of the vibrating gyroscope according to the embodiment of the present invention.

FIG. 5 is a perspective explanatory view showing a first example of a conventional vibrating gyro.

FIG. 6 is a perspective explanatory view showing a second example of a conventional vibrating gyro.

[Explanation of symbols]

10 Vibration gyro 11 oscillators 13 First Piezoelectric Substrate 14 Second piezoelectric substrate 15 Metal plate 15a Metal plate body 15b support member 16a, 16b First strip electrode 18 Second strip electrode 21 Mounting board

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01C 19/56 G01P 9/04

Claims (2)

(57) [Claims] 1. A first piezoelectric substrate which is polarized in a thickness direction, a second piezoelectric substrate which is laminated on the first piezoelectric substrate and is polarized in the thickness direction, and the first piezoelectric body. A metal plate as an intermediate electrode layer provided between a substrate and the second piezoelectric substrate; a first strip electrode formed on one main surface of the first piezoelectric substrate; A second belt-shaped electrode formed on one main surface of the body substrate, and a driving unit for driving the vibrator in the thickness direction, which includes a columnar vibrator, and a displacement generated by bending the vibrator. a vibrating gyroscope comprising: a detection means for detecting the the said metal plate is narrower at a node near the point of the vibrator
And a narrow portion of the metal plate body formed on the
Parallel to the main surfaces of the first and second piezoelectric substrates
The first and second piezoelectric elements which are integrally provided with a support member extending in the width direction of the vibrator while having a surface, and which are near the node point of the vibrator.
Reduce the thickness of the metal plate between the body substrate
Or the gold near the node point of the oscillator
The first and second pressures in the portion sandwiching the metal plate
By scraping off the other main surface of the electric substrate, the metal plate and the first piezoelectric substrate and the second piezoelectric substrate are not in contact with each other near the node point of the vibrator. Let's say a vibrating gyro. 2. The support member for the metal plate is the vibration member.
It extends from the vicinity of the node point of the child in the width direction of the oscillator,
Previously by the being bent so as to have a longitudinal direction substantially perpendicular to the plane of the oscillator, characterized in, vibrating gyroscope according to claim 1.