JP3732601B2 - Energy-confined piezoelectric vibration gyroscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gyroscope for detecting a rotational angular velocity, and more particularly to a piezoelectric vibration gyroscope using an energy confinement vibration mode of a piezoelectric vibrator.
[0002]
[Prior art]
A piezoelectric vibration gyroscope (hereinafter referred to as a piezoelectric vibration gyro for the sake of simplicity) is a state where a piezoelectric vibrator is excited in a certain direction, and the piezoelectric vibrator is rotated around an axis perpendicular to the excitation direction. , The Coriolis force generated in the direction perpendicular to the excitation direction and the rotation axis is detected, and the rotational angular velocity is detected, and there are various applications. Recently, for example, a car navigation system, It has come to be used for a camera shake correction mechanism of a VTR camera.
[0003]
As a piezoelectric vibration gyro, a piezoelectric vibration gyro using an energy confinement vibration mode using a piezoelectric vibrator that vibrates in an energy confinement vibration mode in which vibration energy is concentrated in the vicinity of a drive electrode is disclosed in, for example, Japanese Patent Laid-Open No. 62-162915. And Japanese Patent Laid-Open No. 5-322580.
[0004]
The piezoelectric vibration gyro using the energy confinement vibration mode has the advantage that the vibration energy is concentrated in the local area of the piezoelectric vibrator, so that the piezoelectric vibrator can be supported easily and easily, and there is no need for a free lead wire. There is.
[0005]
Japanese Patent Laid-Open No. Sho 62-162915 discloses that in order to confine vibration energy locally, the vibrator is locally thickened, the portion is polarized in the thickness direction, and a drive electrode is provided on the opposed end face of the thick local area. A device in which a detection electrode is provided on a side surface is disclosed. As another example, a drive electrode and a detection electrode are provided on one surface of a piezoelectric plate, and a cross finger electrode is provided as a detection electrode between the drive electrodes.
[0006]
In Japanese Patent Laid-Open No. 5-322580, a partial area of a piezoelectric plate is polarized in the thickness direction, two sets of counter electrodes are provided on the main surface of the polarization area, and the counter directions are perpendicular to each other, and one counter electrode is driven. A piezoelectric vibration gyro using the other counter electrode as a detection electrode is disclosed.
[0007]
[Problems to be solved by the invention]
In the conventional piezoelectric vibration gyro described above, when a piezoelectric plate is excited with a pair of drive electrodes in a direction perpendicular to the polarization direction of the piezoelectric plate, and the rotation of the polarization direction is applied, the direction is perpendicular to the polarization direction and the excitation direction. the resulting Te Coriolis force by the pair of detecting electrodes Karae an output signal corresponding to the vibration, although detected by the detecting circuit the rotation angle speed detecting circuit from the output signal, the rotation is not applied when vibration due to the Coriolis force is generated Therefore, it is not possible to test whether the piezoelectric vibration gyro is operating correctly without applying rotation.
[0008]
In addition, the piezoelectric vibration gyro using the energy confinement vibration mode disclosed in Japanese Patent Application Laid-Open No. 62-162915 has a need to locally increase the thickness of the piezoelectric plate or form a cross finger electrode. There are difficulties. In addition, since the pair of drive electrodes and the pair of detection electrodes are provided in the vicinity of each other, the drive electric field applied from the drive electrodes to the piezoelectric plate is affected by the detection electrodes, and the accuracy of the drive electric field changes due to the change of the drive field direction. The shortcoming is seen.
[0009]
The piezoelectric vibration gyro using the energy confinement vibration mode disclosed in Japanese Patent Laid-Open No. 5-322580 is simple in configuration and easy to manufacture, but a pair of drive electrodes and a pair of detection electrodes are provided in the vicinity of each other. The drive electric field applied from the drive electrode into the piezoelectric plate is affected by the detection electrode, the drive electric field direction changes, and it is difficult to obtain an accurate detection output.
[0010]
Accordingly, an object of the present invention is to provide a piezoelectric vibration gyro using an energy confinement vibration mode having a function of testing whether or not the piezoelectric gyro operates correctly without rotating the piezoelectric plate.
[0011]
In addition, the present invention achieves the above-described object and prevents the output electrode from adversely affecting the drive electric field by sharing the output electrode as a part of the drive electrode in a limited region of the main surface of the piezoelectric plate. It is an object of the present invention to provide an energy confinement piezoelectric vibration gyro with a simple structure, a small size, and high accuracy.
[0012]
[Means for Solving the Problems]
The present invention includes a piezoelectric vibrator having a piezoelectric plate driving electrode pairs and detection electrode pairs are formed on the main surface of the region that having a polarization in the thickness direction of the piezoelectric plate,
Leave exciting the area between the drive electrode pairs of said piezoelectric plate in a first direction perpendicular to the thickness direction by applying a driving voltage to the driving electrode pairs, rotating parallel said piezoelectric plate is in the thick viewed direction rotation from the input signal by receiving a signal corresponding to the vibration due to the Coriolis force generated perpendicular second direction the thick viewed direction and said first direction when rotated about the shaft from the detection electrode pair as an input signal in the energy trapping piezoelectric vibrating gyroscope utilizing vibration and a detection circuit for detecting angular velocity,
It formed on a main surface of the piezoelectric plate in a region outside between the driving electrode pairs, energy-trap piezoelectric resonator, characterized in that it comprises a test auxiliary electrodes for exciting the piezoelectric plate in the second direction It is a gyroscope.
[0013]
The piezoelectric vibration gyroscope of the present invention further includes a drive source connected to one of the drive electrode pairs for generating the drive voltage, a switch for selectively applying the drive voltage from the drive source to the auxiliary electrode, which is connected to the output of the detection circuit, the drive source may be have a determining circuit for determining an abnormality of the detection output when connected to the auxiliary electrode.
[0014]
According to one aspect of the present invention, the drive electrode pair has a direction perpendicular to the first direction at one of two positions on the main surface and spaced apart from each other by a predetermined distance in the first direction. A strip-shaped first electrode provided to extend to the other, and strip-shaped second and third electrodes provided at the other position so as to extend at a distance from each other in a direction substantially perpendicular to the first direction. The auxiliary electrode is provided to extend in parallel with the first direction along a region between the first electrode and the second and third electrodes, together form so as to apply a driving voltage for excitation between the first electrode and the second and third electrodes, corresponding to the second and third electrodes, the vibration generated in said second direction the used as the detection electrode pair obtain the output voltage, between the first electrode and the second and third electrodes The piezoelectric vibrating gyroscope, characterized in that utilizing the energy confinement mode of thickness shear vibration that occurs can be obtained.
[0015]
The second and third electrodes are respectively connected to first and second current detection circuits having a virtual ground function, and an excitation drive voltage is applied to the first electrode, It is preferable that the detection output is obtained from the difference voltage generated between the outputs of the second current detection circuit.
[0016]
The circuit includes a differential circuit connected between outputs of the first and second current detection circuits for detecting a difference between output voltages of the current detection circuits, and a synchronization circuit connected to the differential circuit output. A detection circuit; and a rectifier circuit connected to the output of the synchronous detection circuit; the determination circuit is connected to an output of the rectification circuit; and the drive source is the first and second current detection circuits. An oscillation circuit for oscillating a signal having a self-excitation drive frequency connected between the outputs, and a drive circuit for outputting an alternating voltage of the self-excitation drive frequency as the drive voltage connected to the output of the oscillation circuit; It is good to compose with.
[0017]
As the piezoelectric plate, piezoelectric ceramics is used, and only the region between and in the vicinity of the first to third electrodes of the piezoelectric ceramics is polarized in the thickness direction.
[0018]
A piezoelectric crystal plate having a polarization axis in the thickness direction can also be used as the piezoelectric plate.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view showing a configuration of a vibrator of an energy-confined vibration gyro according to an embodiment of the present invention. As shown in FIG. 1, the piezoelectric vibrator uses a piezoelectric plate 10 made of, for example, a piezoelectric ceramic plate such as PZT or barium titanate and having a polarization axis at the center in the thickness direction. A strip-shaped first electrode 11 is provided on the main surface of the central portion of the piezoelectric plate 10. A second electrode 12 and a third electrode 13 are formed away from each other at a predetermined distance from the first electrode 11 in parallel with the first electrode. These electrodes 11, 12, 13 are connected to terminal portions 14, 15, 16 for leading to the outside.
[0020]
Furthermore, outside the region between the first electrode 11 and the second and third electrodes 12 and 13, and the auxiliary electrode 21 is provided so as to extend along the region. A terminal portion 23 is also connected to the auxiliary electrode 21.
[0021]
Note that these electrodes and terminal portions are preferably made of silver paste or gold sputtering. Of course, other conductive films can be used. A lead wire can also be used without providing a terminal portion for leading to the outside on the vibrator.
[0022]
As shown in the figure, the three-dimensional coordinates are determined with the thickness direction being the Z axis, the opposing direction of the electrodes being the X axis, and the direction orthogonal to these being the Y axis.
[0023]
In operation, when a driving voltage (alternating current) is applied between the first electrode 11 and the second and third electrodes 12 and 13, vibration in the X direction is excited. In this state, when the piezoelectric plate 10 rotates around the Z axis, vibration due to the Coriolis force is generated in the Y direction, and an electromotive force is generated between the second and third electrodes. By detecting this electromotive force, it is possible to detect the magnitude of vibration caused by the Coriolis force, and hence the rotational angular velocity.
[0024]
Since the vibration energy is confined in the central portion of the piezoelectric plate and does not reach the periphery, it is easy to support the peripheral portion of the piezoelectric plate.
[0025]
Next, when the driving voltage is supplied to the first electrode 11 and applied to the auxiliary electrode 21 while the piezoelectric vibrator 1 is stationary without being rotated, the driving electric field is applied to the auxiliary electrode 21 and the second electrode 21. Further, the piezoelectric plate 10 is excited substantially in the Y direction because it is applied between the third electrode 12 and the third electrode 12. As a result, vibration in the Y direction equivalent to when rotation is applied while driving in the X direction is generated. As a result, an output signal corresponding to the vibration in the Y direction can be obtained from the second and third electrodes. From this output signal, it can be determined whether or not the piezoelectric vibration gyro, in particular, the detection circuit connected to the vibrator is normal. In other words, the piezoelectric vibration gyro can be tested by switching the drive voltage application to the auxiliary electrode.
[0026]
FIG. 2 is a modification of the piezoelectric vibrator 1 of FIG. 1, in which another auxiliary electrode 22 and a terminal portion 24 connected thereto are provided as an auxiliary electrode for testing opposite to the auxiliary electrode 21 of FIG. It is. The auxiliary electrodes 21 and 22 will be referred to as first and second auxiliary electrodes, respectively. By switching the drive voltage application from the first auxiliary electrode 21 to the second auxiliary electrode 22, it becomes equivalent to the rotation in the opposite direction being given, and this is equivalent to giving the rotation in the opposite direction to the piezoelectric vibrating gyroscope. Test can be done.
[0027]
FIG. 3 is a block diagram showing a circuit configuration connected to the piezoelectric vibrator 1 of FIG. 1 or FIG. Referring to FIG. 3, current detection circuits 31 and 32 are connected to the second and third electrodes 12 and 13 of the piezoelectric vibrator 10, respectively. A differential amplifier circuit 33 is connected to the output side of the current detection circuits 31 and 32, and a detection output of the piezoelectric vibration gyro is obtained via the synchronous detection circuit 34 and the rectification circuit 35. On the other hand, the current detection circuits 31 and 32 are connected to the oscillation circuit 36 for satisfying the self-excited oscillation condition, and are connected to the first electrode 11 via the X vibration drive circuit 37 for applying the X direction vibration. A self-excited oscillation circuit is configured. By this self-excited oscillation circuit, an AC voltage having a frequency substantially equal to the resonance frequency of the thickness shear vibration of the piezoelectric vibrator is applied to the electrode 11. The main force of the oscillation circuit 36 is connected to a Y vibration drive circuit 38 for applying a Y direction vibration, and its output is selectively connected to the auxiliary electrode 21 (or 22) via the switch circuit 39. The A determination circuit 40 is connected to the output side of the rectifier circuit 35 to determine whether or not the piezoelectric vibration gyro is operating normally from the detected output.
[0028]
FIG. 4 is a diagram showing a configuration example of the current detection circuits 31 and 32 of FIG. 3 and has a function of virtually grounding the second and third electrodes 12 and 13. In this circuit, the non-inverting input terminal (+) of the operational amplifier 41 is grounded to the reference voltage, and a resistor R is connected from the output terminal of the operational amplifier 41 to the inverting input terminal. The inverting input terminal (−) is always kept at the ground reference potential by the virtual ground function of the operational amplifier. When a current flows into the inverting terminal, it is converted into a voltage by the resistor R. That is, an output of Vout = −iR is obtained. In other words, this current detection circuit is a circuit that has an input impedance that is substantially zero and that can obtain an output voltage proportional to the input current.
[0029]
This current detection circuit is used for the current detection circuits 31 and 32 of FIG. At that time, the inverting input terminal (−) is connected to the second and third electrodes 12 and 13. As a result, the drive voltage is applied between the first electrode 11 and the second and third electrodes 12 and 13, and the electromotive force between the second and third electrodes 12 and 13 is detected by current detection. The potential difference between the outputs of the circuits 31 and 32 can be detected.
[0030]
Next, the driving principle of the piezoelectric vibrator in the above embodiment of the present invention will be specifically described with reference to the drawings.
[0031]
FIGS. 5A and 5B are a plan view and a cross-sectional view showing only the electrode portion, respectively, showing the basic structure of the energy confinement type vibrator shown in FIGS. Referring to FIGS. 5 (a) and 5 (b), on the same surface of the central portion of the piezoelectric plate 10 polarized in the thickness direction (Z-axis direction), a slit-like shape facing each other with a gap in the X-axis direction. Electrodes D1 and D2 are formed. T1 and T2 are terminal portions. When a voltage is applied between the terminals T1 and T2, an electric field in a direction substantially parallel to the plane of the plate (X direction) is applied to the region (interelectrode region) of the piezoelectric plate 10 between the opposing electrodes D1 and D2. Therefore, strain in the X direction occurs in the inter-electrode region due to the interaction with the polarization in the thickness direction (Z-axis direction) orthogonal to the electric field. When the dimensions of the electrodes D1 and D2 are designed in accordance with the characteristics of the piezoelectric plate 10 and the applied voltage is an AC voltage having a frequency that matches the resonance frequency of the interelectrode region, thickness shear vibration can be excited in the interelectrode region. . The vibration is trapped without being attenuated and propagated around the area between the electrodes. That is, an energy confinement oscillator can be configured. Further, since this vibration is a thickness shear vibration caused by an electric field parallel to the surface of the piezoelectric plate, it is called a parallel electric field excitation type thickness shear vibration. The thickness shear vibration is vibration in which the direction of displacement of the piezoelectric plate is parallel to the plate surface and the wave propagation direction is in the thickness direction of the plate. In order to illustrate the state of this vibration, FIG. 6 shows a displacement distribution in the thickness direction (Z-axis direction) when resonating at a half wavelength.
[0032]
The vibrator shown in FIGS. 1 to 3 uses the above basic structure. That is, the 1st electrode 11 is D1 electrode, and the 2nd electrode 12 and the 3rd electrode 13 which oppose this are D2 electrodes. The D2 electrode is divided into two to constitute a detection electrode, constitutes a second electrode 12 and a third electrode 13, and is connected to current detection circuits 31 and 32 each having a virtual ground function. Thereby, since the second electrode 12 and the third electrode 13 are virtually maintained at the reference potential, they can be regarded as ground terminals in terms of potential. Therefore, when a driving voltage for excitation having a frequency substantially equal to the resonance frequency of the thickness shear vibration mode of the piezoelectric plate is applied to the first electrode 11, the first, second, In addition, the middle point of the straight line connecting the center of the first electrode 11 and the centers of the second and third electrodes 12 and 13 is connected to a region (interelectrode region) surrounded by the third electrodes 11, 12 and 13. Thickness shear vibration in the energy confinement vibration mode in the direction of the straight line (X direction) occurs.
[0033]
In this state, when the piezoelectric plate 10 is rotated about an axis orthogonal to the principal surface, the direction of the thickness shear vibration that is excited (Y direction) is caused by the action of the Coriolis force. Thickness sliding vibration occurs. Due to the thickness shear vibration generated by this Coriolis force, the impedance between the first electrode 11 and the second electrode 12 and between the first electrode 11 and the third electrode 13 changes, and as a result, The current value flowing into the current detection circuits 31 and 32 changes. As described above, since the second electrode 12 and the third electrode 13 are arranged symmetrically with respect to the direction of the thickness shear vibration that is excited, the second electrode 12 and the third electrode 13 are caused by the Coriolis force flowing into the current detection circuits 31 and 32. The currents that change due to the vibration are equal in amplitude and different in phase by 180 degrees. Therefore, the output voltages of the current detection circuits 31 and 32 are also voltages that are 180 degrees out of phase with each other, the difference between these output voltages is detected as a differential voltage by the differential circuit 33, and this voltage is detected by the synchronous detection circuit 34. The detection output can be obtained as a DC output voltage proportional to the applied rotational angular velocity by performing synchronous detection at the timing of
[0034]
On the other hand, the current detection circuits 31 and 32 are connected to the electrode 11 through an oscillation circuit 36 and an X vibration drive circuit 37 for satisfying the self-excited oscillation condition, and constitute a self-excited oscillation loop. As a result, the resonance frequency of the vibrator is automatically adjusted and the vibrator can be driven efficiently, so that a highly sensitive gyro can be obtained.
[0035]
In addition, when the piezoelectric vibrator 1 is in a stationary state where no rotation is applied, if the switch 39 is turned on and a Y vibration drive voltage is applied to the auxiliary electrode 21, vibration in the Y direction is generated and rotation is applied as described above. When this occurs, an equivalent vibration occurs, so that a detection output is obtained from the rectifier circuit 35. The determination circuit 40 determines whether or not it is operating normally based on the level of the Y vibration drive voltage and this detection output, and outputs a determination signal.
[0036]
Here, the phrase “having polarization in the thickness direction” of the piezoelectric plate used in the present invention is not limited to being polarized only in the thickness direction, but also includes one having a polarization component in the thickness direction. Of course, since the larger polarization component in the thickness direction is better, the one polarized only in the thickness direction is most advantageous.
[0037]
When a piezoelectric ceramic is used as the piezoelectric plate 10, polarization processing is required as is well known, but the polarization region may extend over the entire piezoelectric plate, or may be limited to only a region confining vibration. .
[0038]
As the piezoelectric plate 10, a piezoelectric crystal plate (for example, quartz, LiNbO3, LiTO3, etc.) can be used. In that case, in order to have a polarization axis in the thickness direction, a Z-cut plate is most preferable, but a rotating Y-cut plate can also be used.
[0039]
【The invention's effect】
According to the present invention, the drive voltage is applied to the drive electrodes of the piezoelectric vibrator so that the drive electrodes are excited in the X direction, and the Y-direction vibration based on the Coriolis force generated by the rotation applied to the piezoelectric vibrator is detected. In an energy confinement type piezoelectric vibration gyro that is obtained as an output signal from the electrodes and detects the angular velocity of rotation from the output signal to the detection circuit, the auxiliary extending in the X direction along the region outside the region between the drive electrodes Since an electrode is provided and a drive voltage is applied to the auxiliary electrode without any rotation, the vibration in the Y direction is forcibly generated. Therefore, the operation of the piezoelectric vibration gyro is normal from the detection signal at that time. You can know whether or not.
[0040]
Furthermore, according to the present invention, driving is performed using only a pair of slit-like electrodes arranged in parallel on the main surface of the piezoelectric plate, and one of the pair of electrodes is divided into two to detect electrodes. Therefore, the drive electric field is not adversely affected by the presence of the detection electrode, and the Y-direction vibration can be detected while maintaining the electric field for exciting the X-direction vibration. Obtainable. In addition, since energy-confined vibration is used, a gyro that is easy to support and highly reliable can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a piezoelectric vibrator according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a configuration of a piezoelectric vibrator according to another embodiment of the present invention.
FIG. 3 is a block diagram showing a circuit configuration of a gyro using a piezoelectric vibrator.
4 is a circuit diagram showing an example of a current detection circuit used in the circuit of FIG. 3. FIG.
5A and 5B are diagrams showing a basic structure of a vibrator employed in the piezoelectric vibrator of FIGS. 1 and 2, wherein FIG. 5A is a plan view, and FIG. 5B is a side view excluding electrode terminal portions.
6 is a diagram showing a displacement distribution in the thickness direction in the thickness shear vibration of the vibrator having the basic structure of FIG. 5; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator 10 Piezoelectric plate 11 1st electrode 12 2nd electrode 13 3rd electrode 14, 15, 16, 23, 24 Terminal part 21 1st auxiliary electrode 22 2nd auxiliary electrode 31 Current detection circuit 32 Current detection circuit 33 Differential circuit 34 Synchronous detection circuit 35 Rectifier circuit 36 Oscillation circuit 37 X vibration drive circuit 38 Y vibration drive circuit 39 Switch 40 Determination circuit 41 Operational amplifier

Claims (7)

A piezoelectric vibrator having a piezoelectric plate driving electrode pairs and detection electrode pairs are formed on the main surface of the region that having a polarization in the thickness direction of the piezoelectric plate,
Leave exciting the area between the drive electrode pairs of said piezoelectric plate in a first direction perpendicular to the thickness direction by applying a driving voltage to the driving electrode pairs, rotating parallel said piezoelectric plate is in the thick viewed direction rotation from the input signal by receiving a signal corresponding to the vibration due to the Coriolis force generated perpendicular second direction the thick viewed direction and said first direction when rotated about the shaft from the detection electrode pair as an input signal in the energy trapping piezoelectric vibrating gyroscope utilizing vibration and a detection circuit for detecting angular velocity,
They formed on a main surface of the piezoelectric plate in a region outside between the driving electrode pairs, energy-trap piezoelectric resonator, characterized in that it comprises a test auxiliary electrodes for exciting the piezoelectric plate in the second direction Gyroscope. The piezoelectric vibrating gyroscope of claim 1,
A drive source connected to one of the drive electrode pair for generating the drive voltage; a switch for selectively applying a drive voltage from the drive source to the auxiliary electrode; and an output of the detection circuit for connecting the drive A piezoelectric vibration gyroscope comprising: a determination circuit for determining an abnormality in detection output when a source is connected to the auxiliary electrode. The piezoelectric vibrating gyroscope of claim 2,
The drive electrode pair is:
A strip-shaped first electrode provided on one of the two positions on the main surface and spaced apart from each other in a first direction by extending in a direction perpendicular to the first direction; ,
A strip-like second and third electrodes provided at the other position so as to extend in a direction substantially perpendicular to the first direction at a distance from each other;
The auxiliary electrode is provided to extend in parallel with the first direction along a region between the first electrode and the second and third electrodes,
Together form so as to apply a driving voltage for excitation between said first electrode and said second and third electrodes, said second and third electrodes, the vibration generated in said second direction used by said detecting electrode pair to obtain a corresponding output voltage,
A piezoelectric vibration gyroscope using an energy confinement mode of thickness-shear vibration generated between the first electrode and the second and third electrodes. The piezoelectric vibrating gyroscope of claim 3,
The second and third electrodes are respectively connected to first and second current detection circuits having a virtual ground function, and an excitation drive voltage is applied to the first electrode, A piezoelectric vibration gyroscope configured to obtain a detection output from a differential voltage generated between outputs of a second current detection circuit. The piezoelectric vibrating gyroscope of claim 4,
The detection circuit is connected between the outputs of the first and second current detection circuits, and is connected to a differential circuit for detecting a difference in output voltage between the current detection circuits, and to the differential circuit output. A synchronous detection circuit; and a rectifier circuit connected to an output of the synchronous detection circuit, wherein the determination circuit is connected to an output of the rectifier circuit, and the drive source is the first and second currents An oscillation circuit for oscillating a self-excitation drive frequency signal connected between the outputs of the detection circuit, and a drive circuit connected to the output of the oscillation circuit and outputting an AC voltage of the self-excitation drive frequency as the drive voltage A piezoelectric vibration gyroscope characterized by comprising: In the piezoelectric vibration gyroscope according to any one of claims 1 to 5,
A piezoelectric vibration gyroscope using piezoelectric ceramics as the piezoelectric plate, wherein only the region between and in the vicinity of the first to third electrodes of the piezoelectric ceramics is polarized in the thickness direction. In the piezoelectric vibration gyroscope according to any one of claims 3 to 5,
A piezoelectric vibration gyroscope using a piezoelectric crystal plate having a polarization axis in the thickness direction as the piezoelectric plate.

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