JPH1089970A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance detection sensitivity by providing a driving piezoelectric element for exciting an oscillator in a specified direction and a pair of piezoelec tric elements for detecting rotation of the oscillator on the side face of the oscillator having a pair of opposite concave and convex faces. SOLUTION: The angular velocity sensor 1 comprises a driving piezoelectric element 3 for exciting an oscillator 2 in a specified direction and a pair of piezoelectric elements 4A, 4B for detecting rotation of the oscillator fixed to the side face of the oscillator 2. The oscillator 2 has one concave side face 2A and the other convex side face 2B wherein the convex side face 2B defines an edge part 2C while the concave face 2A and the convex face 2B define edge parts 2D, 2E. The piezoelectric element is fixed to the side face of the oscillator 2 substantially in the center thereof and comprises a piezoelectric layer 6 and a pair of electrode layers 7A, 7B formed on the opposite sides thereof. The angular velocity sensor 1 is connected with a drive detection circuit and a Coriolis force is detected by connecting the driving piezoelectric element 3 and the pair of piezoelectric elements 4A, 4B with the drive detection circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor used in a direction detection used in a car navigation system or the like and a camera shake detection of a camera-integrated video tape recorder or the like, and particularly to an angular velocity sensor using a piezoelectric element.

[0002]

2. Description of the Related Art Conventionally, an angular velocity sensor has been used for an aircraft or the like to detect an angular velocity in an inertial coordinate system and calculate a traveling direction of the aircraft or the like. However, in recent years, the angular velocity sensor has been applied as an auxiliary function of a navigation system mounted on a car or to a camera shake detection function of a camera integrated video tape recorder, and the demand for the sensor has been rapidly increasing.

As shown in FIG. 10, such an angular velocity sensor includes a substantially triangular prism-shaped vibrator 100 and this vibrator 10.
0, three piezoelectric elements 101 arranged on three side surfaces,
A pair of support members 102 for supporting the vibrator 100 are provided. In this angular velocity sensor, three piezoelectric elements 1
Reference numeral 01 denotes a substantially rectangular shape slightly smaller than the side surface of the vibrator 100, and has substantially the same shape. The pair of support members 102 support the vibrator 100 near both ends in the longitudinal direction. At this time, the support member 102 supports the vibrator 100 so as to be in contact with a side formed by adjacent side surfaces of the vibrator 100.

In the conventional angular velocity sensor configured as described above, one of the three piezoelectric elements 101 is used as a driving piezoelectric element 101A for driving and driving the vibrator 100.
The remaining two are used as the detecting piezoelectric element 101B. That is, in this angular velocity sensor, the support member 102
Element 1 disposed on the side opposite to the side supported by
01 is a driving piezoelectric element 101A, and the other two elements arranged on the other side are detection piezoelectric elements 101B.

Therefore, when a driving signal is supplied to the driving piezoelectric element 101A, the vibrator 100 performs bending vibration with the point supported by the supporting member 102 as a fulcrum. In this state, the angular velocity sensor is connected to the vibrator 100 in FIG.
When a rotational movement is made about the Z axis during the middle, a Coriolis force is generated in a direction orthogonal to the vibration direction of the bending vibration.
In this angular velocity sensor, the direction of the bending vibration changes due to the Coriolis force.

The angular velocity sensor can detect the rotational angular velocity by sensing a change in the vibration direction of the bending motion due to the Coriolis force. In this angular velocity sensor, a change in the vibration direction of the bending motion due to the Coriolis force is sensed by taking the difference between the output voltages from the pair of detection piezoelectric elements 101B.

When the drive signal is applied to the drive piezoelectric element 101A, the angular velocity sensor vibrates in the direction indicated by the arrow S in FIG. When the angular velocity sensor performs only the bending motion by the driving piezoelectric element 101A, the pair of detection piezoelectric elements 101B generate substantially the same output voltage.
Therefore, at this time, the pair of detecting piezoelectric elements 101B
Then, when the differential of each output voltage is obtained, it becomes substantially zero.

On the other hand, when the angular velocity sensor causes a change in the vibration direction of the bending motion due to Coriolis force, the output voltage generated from the pair of detection piezoelectric elements 101B depends on the angle between the vibration direction and the detection piezoelectric element 101B. Change. In this case, the pair of detection piezoelectric elements 101B generate different output voltages because the angles formed by the respective detection piezoelectric elements 101B and the vibration direction are different. Then, in this angular velocity sensor, a change in the vibration direction can be sensed by taking a difference between the output voltages from the pair of detection piezoelectric elements 101B. Thereby, the angular velocity sensor can detect the rotational angular velocity.

[0009]

In the conventional angular velocity sensor as described above, the vibrator 100 is formed in a columnar body having a substantially equilateral triangular cross section.
The detecting piezoelectric element 101B was provided on the side surface. In such a conventional angular velocity sensor, the detecting piezoelectric element 100B is disposed so as to have an angle of about 30 ° with respect to the vibration direction of the bending motion by the driving piezoelectric element 101A.

In this conventional angular velocity sensor, the angle at which the pair of detecting piezoelectric elements 101B is disposed is set to 60 ° with respect to the Coriolis force. For this reason, it was difficult for the pair of detection piezoelectric elements 101B to detect the Coriolis force with sufficient sensitivity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an angular velocity sensor having improved detection sensitivity by arranging a piezoelectric element at an optimum position with respect to Coriolis force. For the purpose of providing.

[0012]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems and achieve the above-mentioned object, and as a result, to improve the detection sensitivity of the angular velocity sensor,
The inventors have found that the Coriolis force can be increased by reducing the rigidity of the vibrator and increasing the amplitude of the angular velocity sensor, and have completed the present invention.

That is, the angular velocity sensor according to the present invention comprises:
A vibrator formed on a columnar body and having a pair of concave and convex surfaces facing each other as side surfaces, and a driving piezoelectric element mounted on the side surface of the vibrator and exciting the vibrator in a predetermined direction And a pair of detecting piezoelectric elements attached to the side surface of the vibrator and detecting rotation of the vibrator.

In the angular velocity sensor according to the present invention configured as described above, since the vibrator configured so that the concave surface and the convex surface face each other is used, the rigidity of the vibrator is low. For this reason, in this angular velocity sensor,
When the driving piezoelectric element vibrates the vibrator in a predetermined direction,
Since the resonance frequency of the vibrator is low, the vibration speed is high. Therefore, in this angular velocity sensor, the Coriolis force can be increased, and as a result, the detection sensitivity is improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an angular velocity sensor according to the present invention will be described below in detail with reference to the drawings.

As shown in FIGS. 1 and 2, an angular velocity sensor 1 according to this embodiment has a vibrator 2 formed in a columnar body.
And attached to the side of the vibrator 2
And a pair of detecting piezoelectric elements 4A and 4B attached to the side surface of the vibrator 2 to detect the rotation of the vibrator 2. Further, the angular velocity sensor 1 includes a pair of support members 5A and 5B attached near the both ends in the longitudinal direction of the vibrator 2 to support the vibrator 2. In the following description,
The driving piezoelectric element 3 and the pair of detecting piezoelectric elements 4A and 4B are collectively referred to simply as “piezoelectric element”.

In the angular velocity sensor 1, the vibrator 2
As shown in FIG. 2, one side surface is a concave surface 2A, and the other side surface is a convex surface 2B. This convex surface 2B
Has an edge portion 2C. In addition, these concave surfaces 2A
The convex surface 2B and the convex surface 2B are abutted at a predetermined angle to form edge portions 2D and 2E. As described later, a piezoelectric element is disposed on the side surface of the vibrator 2 configured as described above, and a pair of support members 5A and 5B are attached to the vicinity of a longitudinal vibration node of the edge portion 2C. .

The vibrator 2 is made of, for example, a constant elastic material that generally generates mechanical vibration such as an elinvar. Also, in this vibrator 2, after processing, 400
By heating to ６００600 ° C., the temperature characteristics of the detection sensitivity were adjusted.

In the angular velocity sensor 1, the piezoelectric element is attached to a substantially central portion of the side surface of the vibrator 2, and includes a piezoelectric layer 6 having piezoelectric characteristics and a pair of piezoelectric layers 6 Electrode layers 7A and 7B. The piezoelectric element has a substantially rectangular shape and is formed to be slightly smaller than the side surface of the vibrator 2. In this angular velocity sensor 1, the piezoelectric element has a concave surface 2
One sheet is provided corresponding to the shape of A, and two sheets are provided on the convex surface 2B, for a total of three sheets.

The piezoelectric layer 6 constituting the piezoelectric element is made of, for example, P
It is formed by processing a piezoelectric ceramic such as ZT, but the material is not limited. The electrode layers 7A and 7B constituting the piezoelectric element are made of a conductor such as gold, and are formed on both surfaces of the piezoelectric layer 6 by a method such as electroless plating. The piezoelectric element is connected to the vibrator 2
Are bonded to the concave surface 2A and the convex surface 2B through an thermosetting process using an adhesive such as an epoxy resin.

At this time, the piezoelectric element disposed on the concave surface 2A is first formed as a substantially flat piezoelectric element block. Then, a cut is made in the piezoelectric element block at a substantially central portion of the piezoelectric element block in the direction in which the work is to be started in the longitudinal direction, in parallel with the longitudinal direction. Then, after aligning the cut with the center of the concave surface 2A,
The notch bends the piezoelectric element block. As a result, the piezoelectric element block becomes a piezoelectric element bent substantially at the center corresponding to the surface shape of the concave surface 2A. That is, the piezoelectric element thus formed is used as a pair of piezoelectric layers 6.
Are connected by an electrode layer 7A facing outward.

Further, in the angular velocity sensor 1, a pair of support members 5A and 5B are attached to the vibrator 2 in the vicinity of the vibration node and support the vibrator 2. The support members 5A and 5B are made of, for example, a metal wire and are welded to the vibrator 2 by a technique such as spot welding. At this time, the pair of support members 5A, 5A
B are attached to the edge 2C of the vibrator 2, respectively. Therefore, the pair of support members 5A and 5B support the vibrator 2 at two points. Note that these support members 5A and 5B may be fixed to the vibrator 2 using a conductive paste or the like. And these support members 5
A and 5B may be used as ground terminals in the angular velocity sensor 1.

As shown in FIG. 3, the angular velocity sensor 1 according to the present invention configured as described above is connected to the drive detection circuit 10, and the piezoelectric element is selectively used for driving the vibrator and for detecting vibration. The angular velocity sensor 1 detects the Coriolis force by connecting the driving piezoelectric element 3 and the pair of detecting piezoelectric elements 4A and 4B to the drive detecting circuit 10.

That is, in the angular velocity sensor 1 according to the present embodiment, the piezoelectric element provided on the concave surface 2A is used as the driving piezoelectric element 3, and the remaining two piezoelectric elements provided on the convex surface 2B are used as detecting piezoelectric elements. These are elements 4A and 4B. In the driving piezoelectric element 3, a pair of piezoelectric layers 6 are arranged at a surface including the edge portion 2 </ b> C to which the pair of support members 5 </ b> A and 5 </ b> B are attached, that is, at symmetrical positions with respect to the XZ plane in FIG. Further, the pair of detecting piezoelectric elements 4A and 4B are also arranged at symmetric positions with the XZ plane in FIG. 1 as a plane of symmetry.

The drive detecting circuit 10 to which the angular velocity sensor 1 is connected includes an oscillation circuit 11 to which the driving piezoelectric element 3 is connected and a phase to which the driving piezoelectric element 3 is connected via the oscillation circuit 11. A correction circuit 12, a differential amplifier circuit 13 to which the pair of detection piezoelectric elements 4A and 4B are connected, a synchronous detection circuit 14 connected to the differential amplifier circuit 13,
The DC detection circuit 15 is connected to the synchronous detection circuit 14.

In the angular velocity sensor 1 described above, the driving piezoelectric element 3 described above is connected to the oscillation circuit 11.
The driving signal is applied to the driving piezoelectric element 3 by the oscillation circuit 1.
Supplied from 1. Thereby, the driving piezoelectric element 3
As shown by the X-axis in FIG. 1, the vibrator 2 can be vibrated vertically in a stable manner.

The differential amplifier circuit 13 has the above-described 2
The detection piezoelectric elements 4A and 4B are connected. And
The differential amplifier circuit 13 includes two detection piezoelectric elements 4A and 4B.
, The output voltage from each of them is detected, and the differential of these output voltages is obtained and amplified.

At this time, the two detecting piezoelectric elements 4A, 4A
B is connected to the phase correction circuit 12 and supplies an output voltage to the phase correction circuit 12 as well. That is,
These two detection piezoelectric elements 4A and 4B are also used as feedback piezoelectric elements. Therefore, in the phase correction circuit 12, the output voltages from the two detection piezoelectric elements 4A and 4B are combined and supplied to the oscillation circuit 11 described above.

The phase correction circuit 12 is also connected to a synchronous detection circuit 14, and supplies the output voltage to the synchronous detection circuit 14. As a result, the synchronous detection circuit 14 detects only a component synchronized with the drive signal among the outputs detected by the differential amplifier circuit 13. Further, the synchronous detection circuit 14 is connected to a DC amplification circuit 15. Therefore, the signal detected by the synchronous detection circuit 14 is amplified by the DC amplification circuit 15 and becomes an output signal.

The driving piezoelectric element 3 thus arranged
Vibrates the vibrator 2 in a predetermined direction and a predetermined strength by applying a predetermined drive signal. At this time, the transducer 2 moves along the symmetry plane indicated by the XZ plane in FIG.
It vibrates in a direction parallel to the middle X axis.

At this time, the two detecting piezoelectric elements 4A, 4A
B output the same sine wave, respectively, because they bend similarly. Outputs from the two detection piezoelectric elements 4A and 4B are supplied to the oscillation circuit 11 in a form synthesized by the phase correction circuit 12. In this case, the output from the two detection piezoelectric elements 4A and 4B is corrected by the phase correction circuit 12 for a voltage error and a phase error therebetween. As a result, a predetermined sine wave is output from the oscillation circuit 11 to the driving piezoelectric element 3.

The outputs from the two detecting piezoelectric elements 4A and 4B are detected by the differential amplifier circuit 13 for differential, and are output from the differential amplifier circuit 13 to the synchronous detection circuit 14 in a differential manner. You. Then, the differential signal output from the differential amplifier circuit 13 is detected by the synchronous detection circuit 14 only for a component synchronized with the signal from the phase correction circuit 12 described above.
In this case, the angular velocity sensor 1 includes two detection piezoelectric elements 4.
If it is confirmed that the differential between the outputs from A and 4B is 0, it is possible to detect the non-rotation.

On the other hand, when an external vibration or the like is applied, the angular velocity sensor 1 rotates about the Z axis in FIG.
At this time, Coriolis force is generated in the angular velocity sensor 1 in a direction substantially orthogonal to the vibration direction during non-rotation. Therefore, the vibration direction of the angular velocity sensor 1 is deviated from the vibration direction during non-rotation. At this time, the two detection piezoelectric elements 4A and 4B generate different output voltages because the angles formed by the changed vibration directions are different from each other.

For example, the output voltage from one detecting piezoelectric element 4A increases, and conversely, the other detecting piezoelectric element 4A
The output voltage from B decreases. At this time, the absolute values of the change amounts of the output voltages from the two detection piezoelectric elements 4A and 4B are substantially equal. Therefore, the output from the two piezoelectric elements for detection 4A and 4B is supplied to the oscillation circuit 11 in a combined form, so that approximately the same output as during non-rotation is supplied. Therefore, also in this case, a predetermined sine wave is output from the oscillation circuit 11 to the driving piezoelectric element 3 as in the non-rotation state.

The outputs from the two detecting piezoelectric elements 4A and 4B are supplied to the differential amplifier circuit 1 in the same manner as in the non-rotating state described above.
Differential at 3 Then, in the same manner as in the above-mentioned non-rotation, the synchronous detection circuit 14 detects only the component synchronized with the signal from the phase correction circuit 12. In the case of rotating at a predetermined angular velocity about the Z-axis as described above, the output from the two detection piezoelectric elements 4A and 4B is different, so that the detected signal has a predetermined value. This signal is amplified by the DC amplifier circuit 15 to become an output signal.

The angular velocity sensor 1 can detect the angular velocity by detecting the output signal obtained as described above. That is, the angular velocity sensor 1
Can detect the rotation direction from the polarity of the output signal, and can detect the rotation speed from the magnitude of the output signal.

In the angular velocity sensor 1, as described above, since the side surface of the vibrator 2 is configured so that the concave surface 2A and the convex surface 2B abut, the rigidity of the vibrator 2 is low. As a result, in the angular velocity sensor 1, the vibrator 2 has a low resonance frequency, and vibrates greatly due to the drive signal. Therefore, the angular velocity sensor 1 has improved detection sensitivity. That is, the angular velocity sensor 1 according to the present invention has a larger change in the output signal than the conventional one.

In the angular velocity sensor 1, generally,
The driving piezoelectric element 3 and the detecting piezoelectric elements 4A and 4B disposed on the side surface of the vibrator 2 must all be controlled to have substantially the same resonance frequency. That is, the detection piezoelectric elements 4A and 4B disposed on the side surface of the vibrator 2 have substantially the same output voltage during non-rotation by making the resonance frequencies substantially the same. The driving piezoelectric element 3
By making the resonance frequency substantially the same, the vibrator 2 can be stably vibrated.

In this angular velocity sensor 1, since the resonance frequency of the piezoelectric element can be easily adjusted, the resonance frequency of the piezoelectric element is substantially the same. This angular velocity sensor 1
Specifically, by setting the deviation of the resonance frequency between the piezoelectric elements within ± 3 Hz, a high output can be obtained.

Further, the angular velocity sensor according to the present invention is not limited to the one described above, and has a structure in which the cross section of the vibrator is substantially V-shaped as shown in FIGS. There may be. In the angular velocity sensor 20 according to the second embodiment shown in FIGS. 4 and 5, the same members as those of the above-described angular velocity sensor 1 are denoted by the same reference numerals, and the detailed description of the configuration and operation is omitted. Omitted.

An angular velocity sensor 20 according to the second embodiment has a vibrator 21 formed in a columnar body and having a concave surface and a convex surface as a side surface, and a side surface of the vibrator 21. A driving piezoelectric element 22 mounted to excite the vibrator 21 in a predetermined direction; and a pair of detecting piezoelectric elements 23A and 23B mounted on the side surface of the vibrator 21 to detect the rotation of the vibrator 21. Is provided. Further, the angular velocity sensor 20 includes a pair of support members 5A and 5B attached near a node of vibration in the longitudinal direction of the vibrator 21 and supporting the vibrator 21.

In this angular velocity sensor 20, the vibrator 21 has a substantially V-shaped cross section. One side of the vibrator 21 is a concave surface 21A.
The other convex side surface is referred to as a convex surface 21B. The vibrator 21 has a pair of driving piezoelectric elements 2 on its concave surface 21A.
2, and a pair of detecting pressure transmission elements 23A and 23B are disposed on the convex surface 21B.

The angular velocity sensor 20 according to the second embodiment configured as described above is connected to the drive detection circuit 10 and detects Coriolis force, as shown in FIG. That is, in the angular velocity sensor 20, the pair of driving piezoelectric elements 22 is connected to the oscillation circuit 11, and the pair of detecting piezoelectric elements 23A and 23B are connected to the differential amplifier circuit 13 and the phase correction circuit 1.
2 are connected. Therefore, this angular velocity sensor 2
At 0, the detecting piezoelectric elements 23A and 23B detect vibration and are used for feedback of a self-excited signal. The angular velocity sensor 20 detects a change in the vibration direction due to the Coriolis force as in the case of the angular velocity sensor 1 described in the first embodiment.

In the angular velocity sensor 20, a pair of driving piezoelectric elements 22 are formed on the concave surface 21A. At this time, a drive signal is supplied to each of the pair of drive piezoelectric elements 22 from the oscillation circuit 11.
Thus, the pair of driving piezoelectric elements 22 can stably vibrate the vibrator 21 in the direction indicated by the X axis in FIG.

In the angular velocity sensor 20, the resonance frequencies of the three piezoelectric elements 22, 23A, and 23B can be easily adjusted. In the angular velocity sensor 20, a high output can be obtained by setting the deviation of the resonance frequency between the piezoelectric elements 22, 23A, and 23B within ± 3 Hz.

Further, in the angular velocity sensor 20, the side surface of the vibrator 21 is configured so that the concave surface 21A and the convex surface 21B abut each other, as in the first embodiment described above. Rigidity is low. Thereby, in this angular velocity sensor 20, the vibrator 21
Will have a lower resonance frequency and will vibrate more greatly due to the drive signal. Therefore, this angular velocity sensor 20
Means that the detection sensitivity is improved.

Further, the angular velocity sensor according to the present invention is not limited to the above-described one, and as shown in FIGS.
It may be a columnar body formed by connecting a concave surface and a convex surface that are substantially circular arc surfaces. Note that, in the angular velocity sensor 30 according to the third embodiment shown in FIGS. 7 and 8, the same members as those of the angular velocity sensor 1 according to the above-described first embodiment are denoted by the same reference numerals. Detailed description of the configuration and operation is omitted.

The angular velocity sensor 30 according to the third embodiment has a vibrator 31 which is formed in a columnar body and has a concave surface and a convex surface which abut against each other. A driving piezoelectric element 32 that is attached to excite the vibrator 31 in a predetermined direction, and a pair of detecting piezoelectric elements 33A and 33B that are attached to side surfaces of the vibrator 31 and detect rotation of the vibrator 31; Is provided. Further, the angular velocity sensor 30 includes a pair of support members 5A and 5B attached near a node of vibration in the longitudinal direction of the vibrator 31 and supporting the vibrator.

In the angular velocity sensor 30 according to the third embodiment, one side of the vibrator 31 is a concave surface 31A which is a concave arc surface facing inward, and the other side is a convex surface facing outward. The convex surface 31B is an arc surface. The vibrator 31 has a driving piezoelectric element 3 with respect to the concave surface 31A.
2, and a pair of detecting piezoelectric elements 33A and 33B are provided on the convex surface 31B. At this time, the driving piezoelectric element 32 and the detecting piezoelectric elements 33A and 33B are
It is formed and arranged in an arc shape so as to correspond to the surface shape of 1A and the convex surface 31B.

The angular velocity sensor 30 according to the third embodiment configured as described above is connected to the drive detection circuit 10 and detects the Coriolis force, as shown in FIG. That is, in the angular velocity sensor 30, the driving piezoelectric element 32 is connected to the oscillation circuit 11, and the pair of detecting piezoelectric elements 33
A and 33B are connected to the differential amplifier circuit 13 and the phase correction circuit 12. Therefore, in this angular velocity sensor 30, the detecting piezoelectric elements 33A and 33B detect vibration and are used for feedback of a self-excited signal.
The angular velocity sensor 30 detects a change in the vibration direction due to the Coriolis force as in the case of the angular velocity sensor 1 described in the first embodiment.

In the angular velocity sensor 30, the resonance frequencies of the three piezoelectric elements 32, 33A, 33B can be easily adjusted. In the angular velocity sensor 30, a high output can be obtained particularly by setting the deviation of the resonance frequency between the piezoelectric elements 32, 33A, and 33B within ± 3 Hz.

Further, in this angular velocity sensor 30, since the side surface of the vibrator 31 is configured so that the concave surface 31A and the convex surface 31B abut, similarly to the first embodiment, the vibrator 31 Has low rigidity. Thereby, in the angular velocity sensor 30, the vibrator 31
Will have a lower resonance frequency and will vibrate more greatly due to the drive signal. Therefore, this angular velocity sensor 30
Means that the detection sensitivity is improved.

[0053]

As described in detail above, in the angular velocity sensor according to the present invention, the resonance frequency of the vibrator can be lowered by reducing the rigidity of the vibrator. Thus, the angular velocity sensor according to the present invention vibrates greatly due to the drive signal. Therefore, this angular velocity sensor has improved detection sensitivity.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an angular velocity sensor according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a main part of the angular velocity sensor according to the first embodiment.

FIG. 3 is a block diagram for explaining a drive detection circuit of the angular velocity sensor shown in FIGS. 1 and 2;

FIG. 4 is a perspective view of a main part of an angular velocity sensor according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional view of a main part of an angular velocity sensor according to a second embodiment.

FIG. 6 is a block diagram for explaining a drive detection circuit of the angular velocity sensor shown in FIGS. 4 and 5;

FIG. 7 is a perspective view of a main part of an angular velocity sensor according to a third embodiment of the present invention.

FIG. 8 is a vertical sectional view of a main part of an angular velocity sensor according to a third embodiment.

FIG. 9 is a block diagram for explaining a drive detection circuit of the angular velocity sensor shown in FIGS. 7 and 8;

FIG. 10 is a perspective view of a main part of a conventional angular velocity sensor.

[Explanation of symbols]

1 angular velocity sensor, 2 vibrator, 3 driving piezoelectric element,
4 piezoelectric element for detection, 5 support members, 10 drive detection circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Keiichi Kagami 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Katsuyoshi Kawamata 7-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation

Claims (4)

[Claims] 1. A vibrator formed on a columnar body and having a pair of concave and convex surfaces facing each other as side surfaces, mounted on a side surface of the vibrator, and exciting the vibrator in a predetermined direction. An angular velocity sensor comprising: a driving piezoelectric element to be driven; and at least a pair of detecting piezoelectric elements attached to a side surface of the vibrator and detecting rotation of the vibrator. 2. An oscillation circuit for supplying a signal for causing the vibrator to generate a predetermined vibration to the driving piezoelectric element; and the vibrator based on the vibration of the vibrator detected by the detecting piezoelectric element. The angular velocity sensor according to claim 1, further comprising: a vibration detection circuit configured to detect the angular velocity of the piezoelectric element, wherein the piezoelectric element for detection also serves as feedback to the oscillation circuit. 3. The angular velocity sensor according to claim 1, wherein the vibrator has a substantially V-shaped cross section. 4. The angular velocity sensor according to claim 1, wherein the vibrator is formed by abutting a convex surface and a concave surface, each of which is an arc surface, and has a substantially crescent-shaped cross section.