JP2003166828A - Physical quantity measuring device and vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress noise of a detection signal caused by linear acceleration or a disturbance acting on a vibrator while minimizing rigidity of a driving vibration arm in a physical quantity measuring device detecting a physical quantity by using the vibrator having a bending vibration arm. <P>SOLUTION: The physical quantity measuring device, for example, a vibrating type gyroscope is provided with the vibrator, a driving means of applying driving vibration to the vibrator, a detecting means of acquiring an output signal based upon detection vibration applied to the vibrator in response to the physical quantity, and a detecting circuit processing the output signal and acquiring a detection signal corresponding to the physical quantity. The vibrator is provided with at least one bending vibration arm 1A and 1B bending and vibrating in a predetermined plane (an X-Y plane). The bending vibration arm is provided with at least one pair of mutually opposing base parts 2A and 2B and a connecting part 3 connecting the base parts 2A and 2B. A pair of recessed parts 8A and 8B is formed by the connecting part 3 and the pair of base parts 2A and 2B. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a physical quantity measuring device and a vibrator.

[0002]

2. Description of the Related Art Piezoelectric vibrating gyroscopes utilize the fact that when angular velocity is applied to a vibrating object, a Coriolis force is generated in a direction perpendicular to the vibrating object. Then, the principle is analyzed by a mechanical model (for example, "Acoustic Wave Element Technology Handbook", Ohmsha, Nos. 491-497).
page).

The applicant has been making various studies on the application of the vibration type gyroscope, and examined the use of the vibration type gyroscope as a rotation speed sensor used in a vehicle control method of a vehicle body rotation speed feedback type of an automobile. . In such a system, the steering wheel direction itself is detected by the rotation angle of the steering wheel. At the same time, the rotational speed at which the vehicle body is actually rotating is detected by the vibration gyroscope. Then, the direction of the steered wheels and the actual rotation speed of the vehicle body are compared to obtain a difference, and the wheel torque and the steering angle are corrected based on the difference,
Achieve stable vehicle body control.

In such control, highly accurate detection of angular velocity is indispensable. However, if high-accuracy angular velocity detection is attempted, unnecessary displacement easily occurs in the flexural vibration arm of the vibrator, and the unnecessary displacement causes an error immediately in the detection signal from the arm. That is, in the vibration type gyroscope, the driving vibration arm of the vibrator is excited, the vibrator is rotated or rotated in this state, and the detection vibration excited by the vibrator is detected by the detection electrode attached to the detection vibration arm. To detect. The alternating-current output signal thus obtained is supplied to the detection circuit, processed so as to reduce the influence of drive vibration as much as possible, and finally an output signal corresponding to the rotational angular velocity is obtained. This output signal is usually output as a DC voltage value. Therefore, the influence of unnecessary vibration or displacement immediately affects the absolute value of the rotational angular velocity as noise, and it is difficult to cut this noise accurately.

The applicant of the present invention has disclosed in Japanese Patent Laid-Open No. 11-125528 that a long through hole is formed in a drive vibration arm and a detection vibration arm of a vibrator. By providing the elongated bending vibration arm with the through hole extending in the longitudinal direction of the arm, the resonance frequency of the arm can be reduced. Further, by providing a drive electrode and a detection electrode on the inner wall surface of this through hole, an attempt was made to reduce the aforementioned unnecessary displacement and vibration.

[0006]

However, as a result of further study by the present applicant, when a through hole is formed in the drive vibration arm or the detection vibration arm, noise may increase in some cases. . For example, when the vibration type gyroscope is mounted on an automobile and used to control the direction of the vehicle body of the automobile, it is necessary to attach a housing containing the vibration type gyroscope to the vehicle body chassis of the automobile. In this case, external vibration (linear acceleration) is transmitted from the vehicle body chassis of the automobile to the vibrator. When such irregular linear acceleration or disturbance is applied, noise may increase.

An object of the present invention is to provide a physical quantity measuring device for detecting a physical quantity by using a vibrator having a bending vibration arm, while suppressing the rigidity of the driving vibration arm to be low and detecting the linear acceleration or disturbance applied to the vibrator. It is to be able to suppress the noise of the signal.

[0008]

SUMMARY OF THE INVENTION The present invention is a physical quantity measuring device for detecting a physical quantity using a vibrator,
Drive means for exciting drive vibration to the vibrator, detection means for obtaining an output signal based on the detected vibration excited by the vibrator according to a physical quantity, and a detection circuit for processing the output signal and obtaining a detection signal corresponding to the physical quantity are provided. The vibrator includes at least one flexural vibration arm that flexurally vibrates in a predetermined plane, and the flexural vibration arm includes at least a pair of bases and a connecting portion connecting these bases. And a pair of concave portions are formed by the connecting portion and the pair of base portions.

Further, according to the present invention, there is provided a vibrator used for detecting a physical quantity, wherein a detected vibration is excited in the vibrator according to the physical quantity while driving vibration is excited in the vibrator, At least one bending vibration arm that bends and vibrates in a predetermined plane is provided, and this bending vibration arm includes at least a pair of base portions and a connecting portion that connects these base portions, and the connecting portion and the pair of base portions. It is characterized in that a pair of concave portions is formed by and.

The present inventor has proposed a physical quantity measuring device, for example, a vibrating gyroscope, in which a vibrating arm for driving and detecting is provided with a flexural vibrating arm that flexibly vibrates in a predetermined plane. The present invention has conceived a shape in which at least a pair of base portions facing each other and a connecting portion that connects these base portions are provided, and a pair of concave portions is formed by the connecting portion and the pair of base portions. By applying a bending vibration arm of such a shape to a vibrator for physical quantity measurement, when disturbance or linear acceleration is applied to the vibrator from the outside, the noise included in the output signal from the vibrator is reduced. It can be reduced. Hereinafter, the reason will be described with reference to the drawings as appropriate.

FIG. 1 is a diagram schematically showing a pair of drive vibration arms 1A and 1B of a vibrator according to an embodiment of the present invention. 2A is a front view of the arms 1A and 1B of FIG. 1 viewed from the second plane 1d side, and FIG. 2B is a view of the arms 1A and 1B viewed from the first plane 1a side. FIG.

Each of the arms 1A and 1B has an elongated shape as shown in FIG. 2, and the cross-sectional shape of the arm is substantially H-shaped as shown in FIG. Arm 1
A and 1B extend straight from a predetermined fixing portion 6.
Each arm 1A, 1B has a predetermined surface (the XY plane in this example)
It is designed to bend and vibrate along the direction of arrow F. The arms 1A and 1B include a pair of first flat surfaces 1a and 1b that are substantially perpendicular to a predetermined surface and a pair of second flat surfaces 1c and 1d that are substantially parallel to the predetermined surface. Each arm 1A, 1B includes a pair of elongated bases 2A, 2B and a base 2
It is composed of a connecting portion 3 for connecting A and 2B. Base 2
Each of A, 2B and the connecting portion 3 has an elongated flat plate shape.
Then, recesses 8A and 8B are provided on both sides of the connecting portion 3, respectively. The recess 8A is formed to be recessed from the second plane 1c toward the center of the arm, and the recess 8B is formed to be recessed from the second plane 1d toward the center of the arm.

When the drive vibrating arm having such a form is adopted, the mass of the arm is reduced by the amount of the recesses 8A and 8B, so that the arm has less resistance to vibration in the direction of arrow F and the resonance frequency can be reduced. .

However, from the viewpoint of reducing the resistance against vibration in the direction of arrow F, it is more preferable to form the through hole by connecting the concave portions 8A and 8B without providing the connecting portion 3. However, when the connecting portion 3 is not provided, the bases 2A and 2B have a strong tendency to vibrate independently of each other. Here, it is assumed that linear acceleration is temporarily applied to the arms 1A and 1B as indicated by an arrow H. Then, each of the bases 2A and 2B is likely to be displaced in response to this disturbance, and therefore the bending vibration of the arm is likely to be affected. Then, external disturbances and linear accelerations appear irregularly not only in the arrow H direction but also in all directions, and it is difficult to predict. As described above, if the deformation and reaction with respect to an irregular disturbance are relatively easy, it is difficult to reduce or cut noise.

On the other hand, in the present invention, by connecting the pair of bases 2A and 2B by the connecting part 3, the connecting part 3 acts as a kind of beam, and the bases 2A and 2B operate integrally. The unnecessary displacement as described above is unlikely to occur.

Further, it is important that the symmetry of the arm with respect to the predetermined plane (XY plane) is increased by providing the pair of recesses 8A and 8B. For this reason, the arm is unlikely to be displaced in only one direction. However, only the recess 8A is provided,
Even if the concave portion 8B is not provided, the base portions 2A and 2B operate integrally, so that the displacement amount itself should be smaller than that when the through hole is formed. However, in this case, the geometrical symmetry of the arm with respect to the predetermined surface is low, which causes the arm to be largely displaced in the direction in which the recess is present, as viewed from the predetermined surface. As a result, flexural vibration in the predetermined plane of the vibrator is likely to be adversely affected for a long period of time.

Furthermore, as shown in FIG. 3, it is more advantageous to apply the present invention to a bending vibration arm provided with a detecting means. The arm 12 has an elongated shape as in FIG. 2 described above. The cross-sectional shape of the arm is substantially H-shaped. The arm 12 has a predetermined surface (X-Y in this example).
It is designed so as to make bending vibration along a plane) as indicated by an arrow G, and this vibration is detected by the detection means as detection vibration. The arm 12 includes a pair of first flat surfaces 12a and 12b that are substantially perpendicular to the predetermined surface, and a pair of second flat surfaces 12c and 12d that are substantially parallel to the predetermined surface.

The arm 12 is composed of a pair of elongated base portions 12A and 12B and a connecting portion 13 connecting the base portions 12A and 12B. The bases 12A and 12B and the connecting portion 13 are each in the shape of an elongated flat plate. Then, recesses 18A and 18B are provided on both sides of the connecting portion 13, respectively. The recess 18A is formed to be recessed from the second plane 12c toward the center of the arm.
B is formed to be recessed from the second flat surface 12d toward the center of the arm.

Also in such a detection vibration arm, unnecessary vibration displacement can be suppressed in response to disturbance or application of irregular linear acceleration, as described above. In particular, when an unnecessary and asymmetrical vibration displacement with respect to a predetermined surface is induced on the detection vibration arm side, the signal is directly superimposed on the genuine detection signal. Therefore, the present invention provides
It is particularly effective when applied to the detection vibration arm.

In a preferred embodiment, at least one bending vibration arm is provided with the driving means.

In a preferred embodiment, at least one flexural vibration arm is provided with detection means.

In a preferred embodiment, the flexural vibration arm includes a pair of first planes substantially perpendicular to the predetermined plane and a pair of second planes substantially horizontal to the predetermined plane. , The recess is provided on the second plane side. Such a shape is illustrated in FIGS. 1 and 3.

In a preferred embodiment, the drive means is
The first drive electrode provided on the first plane and the second drive electrode provided on the inner wall surface of the recess so as to face the first drive electrode are provided.

This embodiment will be illustrated with reference to FIGS. 1 and 2. In this example, the first electrodes 4A and 4B are formed on the first planes 1a and 1b, respectively. Recesses 8A, 8B
On the inner wall surfaces 1e, 1f of the second electrodes 5A, 5B, 5
D and 5F are formed. The second electrodes 5A and 5D face the first electrode 4A, and the second electrodes 5B and 5F face the first electrode 4B.

A conductive film 5 is formed on one surface 1g of the connecting portion 3.
C is formed. The conductive film 5C is connected to the electrodes 5A and 5B and supplies electric power to the electrodes 5A and 5B. A conductive film 5E is formed on the other surface 1g of the connecting portion 3. The conductive film 5E is connected to the electrodes 5D and 5F and supplies electric power to the electrodes 5D and 5F.

In this example, the arms 1A and 1B are caused to flexurally vibrate, and the phase of vibration in the arm 1A and the phase of vibration in the arm 1B are set to opposite phases. That is, the first electrodes 4A, 4B of the arm 1A and the second electrodes 5A, 5B, 5D, 5F of the arm 1B are connected at the same potential, and the second electrodes 5A, 5B, 5D, 5F of the arm 1A are connected. The first electrodes 4A and 4B of the arm 1B are connected at the same potential. The piezoelectric material forming the vibrator is assumed to be polarized in the arrow F direction. In this state, an AC voltage is applied to the bases 2A and 2B as indicated by arrows A, B, C and D. Here, if the phase of the voltage on the base 2A side is opposite to the phase of the voltage on the base 2B side, the displacement of the base 2A and the displacement of the base 2B are in opposite phase. That is, if the base 2A is stretched at a certain moment, the base 2B is contracted,
When the base 2A contracts, the base 2B extends. As a result, the arms 1A and 1B flexurally vibrate in the arrow F direction.
Further, the vibration displacement of the arm 1A and the vibration displacement of the arm 1B have opposite phases.

Further, in the preferred embodiment, as shown in FIG. 3, the detecting means includes the first detecting electrodes 14A and 14B provided on the first flat surfaces 12a and 12b, and the concave portion 1.
Second detection electrodes 15A, 15B, 15 provided on the inner wall surfaces of 8A, 18B so as to face the first detection electrodes.
D and 15F. The conductive film 15C is the electrode 15
It is connected to A and 15B and supplies electric power to the electrodes 15A and 15B. The conductive film 15E is connected to the electrodes 15D and 15F and supplies electric power to the electrodes 15D and 15F.

In the detection vibration arm 12 shown in FIG. 3, the first electrodes 14A and 14B are connected to have the same potential, and the second electrodes 15A, 15B, 15D and 15F are also used.
Are connected to make the same potential. The piezoelectric material forming the arm 12 is assumed to be polarized in the direction of arrow G. In this state, when the arm 12 is flexed and vibrated as indicated by an arrow G,
Since an alternating current is generated between the first electrode and the second electrode, this is taken out as an output signal. Then, the detection circuit performs a predetermined process to extract a detection signal corresponding to the physical quantity.

The physical quantity to be measured in the present invention is
There is no particular limitation. When drive vibration is excited on a vibrator and the vibration state of the vibrator changes due to the influence of the physical quantity on the vibrator during drive vibration, the physical quantity that can be detected by the detection circuit from this change in vibration state is targeted. . As such physical quantity, acceleration, angular velocity, and angular acceleration applied to the vibrator are particularly preferable. An inertial sensor is preferable as the measuring device.

In a preferred embodiment, the oscillator is made of a piezoelectric material, preferably a piezoelectric single crystal.

Examples of the piezoelectric single crystal include quartz, lithium niobate, lithium tantalate, lithium niobate-lithium tantalate solid solution, lithium borate, and langasite. Particularly preferred is a 130 ° Y plate of lithium niobate, lithium tantalate, or lithium niobate-lithium tantalate solid solution.

A design example of each portion of the bending vibration arm of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of the bending vibration arm. Here, the ratio a / b of the thickness a of the connection portion to the thickness b of the base portion (the distance between the pair of second planes) is 0.4 or less from the viewpoint of reducing the resonance frequency of the flexural vibration arm. Is preferable, and 0.
It is more preferably 2 or less. a / b is 0.05 from the viewpoint of suppressing irregular vibration such as torsional vibration of the base when external disturbance or linear acceleration is applied to the arm.
The above is preferable.

The ratio d / c of the width d of the concave portion to the total width c of the bending vibration arm is preferably 0.4 or more, and more preferably 0.6 or more from the viewpoint of reducing the resonance frequency of the bending vibration arm. More preferably, d / c
Is preferably 0.95 or less from the viewpoint of suppressing irregular vibration such as torsional vibration of the base portion when external disturbance or linear acceleration is applied to the arm.

The present invention can be particularly suitably applied to a so-called horizontal type vibrating gyroscope. In the horizontal vibration type gyroscope, the vibrator extends in a predetermined plane substantially horizontal to the rotation axis. In this case, particularly preferably, both the drive vibration arm and the detection vibration arm flexurally vibrate along a predetermined surface. FIG. 5 shows a vibrator 21 according to this embodiment.

In the vibrator 21, the supporting portions 23A and 23B project from the peripheral portion of the base portion 22. Each support part 2
Bending vibration arms (driving vibration arms) 24A, 24B, 2 in the direction orthogonal to the respective support portions from the tip side of 3A, 23B.
4C and 24D are extended. The cross-sectional shape and the front shape of each bending vibration arm are the same as those shown in FIGS. 1 and 2. In addition, in FIG. 5, the drive electrodes and the detection electrodes are not shown in order to make the drawing easy to see. By applying an AC voltage to each of the drive vibration arms 24A-24D as described above, bending vibration is performed in the XY plane as indicated by arrow F.

Further, elongated circumferential flexural vibration arms 25A and 25B project from the peripheral edge of the base portion 22. Each of the arms 25A and 25B has a form as shown in FIG.

When each drive vibrating arm is vibrated as indicated by the arrow F, and the oscillator 21 is rotated about the axis Z in this state, the pair of support portions 23A, 23B are centered at their roots as indicated by the arrow H. As it flexes and vibrates. Corresponding to this, the detection vibration arms 25A and 25B flexurally vibrate around the root of the arm as indicated by an arrow G. A detection signal is generated based on this bending vibration and processed in the detection circuit.

FIG. 6 is a block diagram showing an example of the drive circuit and detection circuit of the vibrator according to this embodiment. The vibrator 21 of this example includes drive electrodes 4A, 4B, 5A, 5
B, 5D, 5F and detection electrodes 14A, 14B are provided. 24A-24D are drive vibration arms, and
5A and 25B are detection vibration arms.

An external self-oscillation circuit 36 is connected to the drive electrodes. At startup, noise is input to the self-excited oscillation circuit 36 from the startup circuit. This noise passes through the oscillator, undergoes frequency selection, and is then input to the AC amplifier 34 for amplification. A part of the output signal from the AC amplifier 34 is taken out, inputted to the rectifier, and converted into the amplitude level (magnitude). A signal of this amplitude is supplied to the amplitude control amplifier 35.
To enter.

The detection circuit 32 is a circuit for processing the output signal of the vibrator and extracting the genuine detection signal. Detection electrodes 14A, 14B, 15A, 15B, 15 of the oscillator
The output signals from D and 15F are supplied to the respective preamplifiers 26A and 26A.
Amplify with B. Each output from each amplifier 26A, 26B contains at least a true detection signal corresponding to the angular velocity. In this example, the detection signals included in the output signals have opposite phases. Therefore, each output signal is input to the subtractor 27 to be subtracted, the influence of drive vibration is canceled out, and a true detection signal is left. Next, the output from the subtractor 27 is passed through the AC amplifier 28, the wave detector 29, the low-pass filter 30, and the limiter 31, and a true detection signal is obtained from the terminal.

The detector 29 detects the output signal using the phase shift signal based on the drive signal. That is, the derivative signal from the driving vibration is passed through the phase shifter 33 and the phase is shifted, for example, by 90 ° to obtain the phase shift signal. When the phase shift signal is input to the detection circuit 29 and the output signal is detected, unnecessary leak signals are eliminated from the detection output, and a true detection signal is obtained. This detected signal is input to the smoothing circuit and its output is amplified.

Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above embodiments. For example, the shape of the base and the shape of the recess are not particularly limited. Further, the polarization direction of the piezoelectric material at the base, the position and shape of the drive electrode and the detection electrode on the vibrating arm are not limited.

[0043]

As described above, according to the present invention, in a physical quantity measuring device for detecting a physical quantity using a vibrator having a flexural vibration arm, the vibration of the driving vibration arm is suppressed while being added to the vibrator. It is possible to suppress noise in the detection signal due to linear acceleration or disturbance.

[Brief description of drawings]

FIG. 1 is a drive vibration arm 1 according to an embodiment of the present invention.
It is a figure which shows typically the shape of the cross section of A and 1B.

2A is a front view of the arms 1A and 1B of FIG. 1 as viewed from a second plane 1d side, and FIG. 2B is a front view of the arms 1A and 1B of FIG. It is the front view seen from.

FIG. 3 is a detection vibration arm 1 according to another embodiment of the present invention.
It is a figure which shows the cross-sectional shape of 2 typically.

FIG. 4 is a cross-sectional view showing a design example of a bending vibration arm of the present invention.

FIG. 5 is a perspective view showing an example of a vibrator of the present invention.

FIG. 6 is a block diagram showing an example of a vibrating gyroscope according to the present invention.

[Explanation of symbols]

1A, 1B, 24A, 24B, 24C, 24D Driving vibration arms 1a, 1b First plane 1c, 1d Second plane 1e, 1f Inner wall surface of recess (inner wall surface facing first plane) 1g Connection part Surface 2
A, 2B, 12A, 12B Base part 3, 13 Connection part 4A, 4B, 14A, 14B First electrode 5
A, 5B, 5D, 5F, 15A, 15B, 15D, 15
F Second electrode 6 Fixing part 8A, 8
B, 18A, 18B Recess 12, 25A, 25
B Detection vibration arm XY plane Predetermined plane
Z rotation axis F, G, H Flexural vibration in a predetermined plane

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshio Morita             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation (72) Inventor Takayuki Kikuchi             2-56, Sudacho, Mizuho-ku, Nagoya-shi, Aichi             Inside Hon insulator Co., Ltd. (72) Inventor Takao Soma             2-56, Sudacho, Mizuho-ku, Nagoya-shi, Aichi             Inside Hon insulator Co., Ltd. F-term (reference) 2F105 AA02 BB03 CC01 CD02 CD06                       CD11 CD13

Claims (18)

[Claims] 1. A physical quantity measuring device for detecting a physical quantity using a vibrator, comprising: a vibrator, drive means for exciting drive vibration to the vibrator, and detected vibration excited to the vibrator according to the physical quantity. Detecting means for obtaining an output signal based on, processing said output signal,
A detection circuit for obtaining a detection signal corresponding to the physical quantity is provided, and the vibrator is provided with at least one bending vibration arm that flexibly vibrates in a predetermined plane, and the bending vibration arm has at least a pair of bases. A physical quantity measuring device, comprising: a connecting portion that connects these base portions, wherein a pair of recesses are formed by the connecting portion and the pair of base portions. 2. The flexural vibration arm includes a pair of first flat surfaces substantially perpendicular to the predetermined surface and a pair of second flat surfaces substantially parallel to the predetermined surface. Device according to claim 1, characterized in that a recess is provided on the side of the second plane. 3. The device according to claim 1, wherein at least one of the bending vibration arms is provided with the driving means. 4. The driving means is a driving electrode provided on the surface of the vibrator, and the driving means is a driving electrode.
The device according to claim 1. 5. The first drive electrode provided on the first plane, and the second drive electrode provided on the inner wall surface of the recess so as to face the first drive electrode. 6. The device of claim 4, further comprising a drive electrode of 6. The device according to claim 1, wherein at least one of the bending vibration arms is provided with the detecting means. 7. The detection means is a detection electrode provided on the surface of the vibrator, wherein the detection means is a detection electrode.
The device according to claim 1. 8. The first detection electrode provided on the first plane and the second detection electrode provided on the inner wall surface of the recess so as to face the first detection electrode. 8. The device according to claim 7, further comprising: 9. Device according to any one of claims 1 to 8, characterized in that it is an inertial sensor. 10. A vibrator used to detect a physical quantity, wherein a detected vibration is excited in the vibrator in accordance with a physical quantity in a state where drive vibration is excited in the vibrator, At least one flexural vibration arm that flexurally vibrates in a plane is provided, and the flexural vibration arm includes at least a pair of base portions and a connection portion that connects these base portions, and the connection portion and the pair of A vibrator, wherein a pair of recesses are formed by the base portion. 11. The vibrator according to claim 10, wherein a detecting means for obtaining an output signal based on the detected vibration is provided on the bending vibration arm. 12. The bending vibration arm includes a pair of first flat surfaces substantially perpendicular to the predetermined surface and a pair of second flat surfaces substantially horizontal to the predetermined surface, Characterized in that a recess is provided on the second plane side,
The vibrator according to claim 10 or 11. 13. The vibrator according to claim 10, wherein the vibrator is made of a piezoelectric material. 14. The piezoelectric material is selected from the group consisting of quartz, lithium niobate, lithium tantalate, lithium niobate-lithium tantalate solid solution, lithium borate and langasite. 13. The vibrator according to item 13. 15. The vibrator according to claim 13, wherein the piezoelectric material is polarized in a direction of a piezoelectric axis substantially parallel to the predetermined surface. 16. A first electrode provided on the first plane, and a second electrode provided on the inner wall surface of the recess so as to face the first electrode. The vibrator according to any one of claims 12 to 15, characterized in that 17. The vibrator according to claim 16, wherein the first electrode and the second electrode are drive electrodes. 18. The vibrator according to claim 16, wherein the first electrode and the second electrode are detection electrodes.