JP2006084273A - Tuning fork type vibrator for piezoelectric vibration gyro - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized, high-characteristic, and low-cost tuning fork type vibrator for a piezoelectric vibration gyro. <P>SOLUTION: La<SB>3</SB>Ga<SB>5</SB>SiO<SB>14</SB>monocrystal is used as a material for forming the tuning fork type vibrator comprising two or more arm parts 12a. A crystal orientation in the vibrator is disposed so that an X axis of the crystal orientation is substantially orthogonal to the axis of each arm part 12a and a Y axis thereof makes an angle of -15°±10° with a surface including the axis of each arm part 12a in order that the highest piezoelectric characteristics are revealed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibrator, particularly a tuning fork vibrator for a piezoelectric vibratory gyroscope, which is a component part of a gyroscope used mainly in an automobile navigation system, attitude control, a camera-integrated VTR camera shake prevention device, and the like.

  A vibrating gyroscope is an angular velocity sensor that utilizes a dynamic phenomenon in which when an angular velocity is applied to an object having velocity, the object itself generates a Coriolis force in a direction perpendicular to the velocity direction.

  More specifically, mechanical vibration, that is, driving vibration, can be excited by applying an electrical signal, and mechanical vibration in a direction orthogonal to the driving vibration, that is, magnitude of detected vibration. When the angular velocity about the axis parallel to the intersecting line of the drive vibration surface and the detection vibration surface is given in a state where the drive vibration is excited in advance in a system that can electrically detect the Coriolis force, As a result, detection vibration is generated and detected as an output voltage.

  Since the detected output voltage is proportional to the magnitude and angular velocity of the drive vibration, the magnitude of the angular velocity can be obtained from the magnitude of the output voltage when the magnitude of the drive vibration is constant. Among the vibrating gyros having such a configuration, a piezoelectric gyro that performs conversion between an electrical signal and mechanical vibration by a piezoelectric effect is referred to as a piezoelectric vibrating gyro.

  At present, a vibrator having a structure in which a vibrator body is made of a piezoelectric material is frequently used as a vibrator used in a piezoelectric vibration gyro because it is excellent in productivity and accuracy. Materials that exhibit piezoelectricity have been actively developed and reported so far, and there are many materials, but there are few materials that are actually applied as electronic devices.

  As a material used for a vibrator for a piezoelectric vibration gyro, the piezoelectric materials that have been put to practical use so far are currently PZT ceramics for polycrystals, quartz for single crystals, and lithium niobate. In addition, these piezoelectric materials have advantages and disadvantages, greatly affecting not only the performance of the piezoelectric vibration gyro but also the shape and productivity.

Here, in order to obtain a small and inexpensive piezoelectric vibration gyro, characteristics required for the piezoelectric material constituting the vibrator are listed as follows.
(1) The electromechanical coupling coefficient is large.
(2) The elasticity and piezoelectricity are stable with respect to temperature changes, and the heat resistance is excellent.
(3) The sound speed is low.
(4) Excellent workability.
(5) The material itself is excellent in productivity.

  And these reasons are as follows. First, if the electromechanical coupling coefficient is large, a predetermined detection sensitivity can be obtained, and the output of the vibrator can be handled with low-amplification amplification. Therefore, the circuit scale for driving detection can be small, and it is small and inexpensive. A piezoelectric vibration gyro is obtained. Second, when the change in elasticity and piezoelectricity with respect to the temperature change is small, the temperature stability of the vibration gyro output can be improved with a simple circuit without using a special correction means, and the circuit scale for driving detection can be reduced. In addition to being excellent in heat resistance, the piezoelectric vibration gyro can be easily reflow mounted, and the terminals of the piezoelectric vibration gyro can be surface mounted. Miniaturization is possible.

  Third, if the sound velocity is low, for example, when considering the downsizing of a vibrator using bending vibration, the resonance frequency can be lowered without making the shape of the vibrator elongated, that is, the sensitivity can be maintained, Therefore, it becomes easy to design small. Fourthly, with regard to workability, as disclosed in Patent Document 1, for example, it is known that if anisotropic etching is possible, miniaturization using photolithographic technology becomes possible. ing.

  Fifth, regarding the productivity of the material itself, the basic conditions include the high level of technical perfection related to material production, the availability of raw materials, the ability to manufacture with a simple process and low cost, and the materials including the manufacturing process. It is an important item that the environmental load is small and cannot be ignored in selecting materials.

  From this point of view, the characteristics of a conventional piezoelectric material that has been put to practical use in a vibrator for a piezoelectric vibration gyro will be described below. Since PZT ceramics have a large electromechanical coupling coefficient, a predetermined sensitivity can be obtained with a small drive detection circuit scale. In addition, since the speed of sound is low, the length of the vibrator can be shortened, which is advantageous for miniaturization. However, since it is a chemically stable material, the processing itself has to rely on mechanical ones, and there is a limit to fine processing. Furthermore, the Curie point is generally low, and when exposed to a high temperature environment such as reflow, there is a considerable deterioration in the piezoelectric characteristics, leading to variations in performance.

  Since quartz is excellent in frequency temperature characteristics, when used as a vibrator for a piezoelectric vibration gyro, it is easy to obtain a vibration gyro that is stable in output with respect to temperature change, that is, with high accuracy. Quartz is a single crystal material suitable for miniaturization of a vibrator because it can be finely processed by etching with hydrofluoric acid. However, since the electromechanical coupling coefficient is small, the efficiency of drive vibration and detection vibration as a vibrator is low, and the circuit configuration tends to be complicated to compensate for it. As a result, the device size cannot be reduced. .

  Lithium niobate has a large electromechanical coupling coefficient, and is generally more stable than a polycrystalline PZT-based ceramic, and is a single crystal material that requires only a very small circuit scale. However, since the speed of sound is high, the resonance frequency of the vibrator becomes high, and there is a problem that the sensitivity is lowered when the size is reduced. At the same time, it is a material that is difficult to etch like PZT, so it does not rely on mechanical processing. There is also difficulty in microfabrication.

Lanthanum gallium silicate (La ₃ Ga ₅ SiO ₁₄ : hereinafter referred to as langasite) single crystal has a larger electromechanical coupling coefficient than quartz, excellent temperature characteristics, low sound speed, and enables fine processing by etching. Therefore, it is a single crystal material suitable for miniaturization. Patent Document 2 discloses a technique of applying a langasite single crystal plate as a material for a vibrator for a piezoelectric vibration gyro.

  In general, a piezoelectric single crystal exhibits anisotropy, and its elasticity, piezoelectricity, and dielectric properties vary depending on the crystal orientation. Documents including Patent Document 2 disclose that the above-described lithium niobate exhibits strong piezoelectric characteristics in an orientation in the vicinity of ± 140 ° Y around the X axis (or ± 50 ° Z around the X axis). Yes.

JP 60-73414 A JP 2001-255152 A

  Therefore, the characteristics inherent to the langasite single crystal can be sufficiently exhibited by matching the crystal orientation and the shape of the vibrator with respect to the langasite single crystal. However, the technology of matching the crystal orientation of the langasite single crystal with the vibrator for a piezoelectric vibration gyro has not been disclosed yet. Accordingly, an object of the present invention is to provide a tuning fork vibrator for a piezoelectric vibration gyro having a small size, high characteristics, and low cost by examining the above-described technique.

  The present invention has been made as a result of examining the relationship between the crystal orientation of the langasite single crystal in the vibrator and the piezoelectric characteristics.

  That is, the present invention provides a tuning fork vibrator having a plurality of arm portions extended from one surface of a substantially rectangular parallelepiped base portion made of a langasite single crystal, and a surface parallel to a plane including the axes of the plurality of arm portions. Is the principal plane, and the crystal orientation of the langasite single crystal is the direction in which the X-axis is perpendicular to the axial direction of the arm portion and the angle between the Y-axis and the principal plane Is a tuning-fork vibrator for a piezoelectric vibration gyro, which is arranged to be -15 ° ± 10 °.

  According to the present invention, in the tuning fork type piezoelectric vibration gyro vibrator, the driving electrode, the detection electrode, and the reference potential electrode are formed on at least one of the main surface and the side surface, and the arm portion between the electrodes is formed. An in-plane vibration in a direction parallel to the main surface and an out-of-plane vibration in a direction orthogonal to the main surface are excited and detected by an electric field piezoelectric lateral effect in the thickness direction or the width direction.

  Further, according to the present invention, in the tuning fork-type piezoelectric vibration gyro vibrator, the two arm portions are integrally formed with the base portion, and the main surfaces of the two arms are close to each other on the main surface. The first electrode, the second electrode, and the third electrode are formed in this order, and in the direction parallel to the main surface due to the piezoelectric lateral effect due to the electric field in the direction parallel to the main surface and perpendicular to the longitudinal direction of the arm portion. An in-plane vibration and an out-of-plane vibration in a direction orthogonal to the main surface are excited and detected. At this time, the two main surfaces forming the electrodes can be either on the same side or on opposite sides.

  Since the tuning fork vibrator for a piezoelectric vibration gyro according to the present invention has a higher electromechanical coupling coefficient and more stable temperature characteristics than the conventional one, a piezoelectric vibration gyro can be configured with a small circuit. That is, it contributes to miniaturization of the piezoelectric vibration gyro. In addition, since the langasite single crystal constituting the vibrator can be etched, it can be processed with higher dimensional accuracy than mechanical processing.

  In addition, according to the crystal orientation arrangement of the present invention, even if an electrode is formed only on one side on the main surface, it functions as a tuning fork vibrator, leading to simplification of the electrode forming process and reducing manufacturing costs. Also contribute. That is, it is possible to provide a tuning fork vibrator for a piezoelectric vibration gyro that is smaller, more accurate, and less expensive than the conventional one.

  The langasite single crystal has a crystal structure belonging to the trigonal group 32. Accordingly, the langasite exhibits symmetry belonging to the point group 32, and exhibits six independent elastic constants and two independent piezoelectric constants. Table 1 is a table in which elastic constants are displayed in a matrix, Table 2 is a table in which piezoelectric constants are displayed in a matrix, and Table 3 is a table in which dielectric constants are displayed in a matrix.

The langasite single crystal exhibits an elastic constant as shown in Table 1, a piezoelectric constant as shown in Table 2, and a dielectric constant as shown in Table 3, and is an electromechanical coupling that is an indicator of the strength of the piezoelectric effect. For the coefficient k, from the arrangement of the piezoelectric constants shown in Table 1, k ₁₁ that is displaced in one direction by applying an electric field to one axis of crystal orientation, or k _{12 that} is displaced in two directions is effective for the piezoelectric effect. That is, since the electromechanical coupling coefficient differs depending on the crystal orientation, the electromechanical coupling coefficient can be increased by matching the crystal orientation and the vibration direction.

  Next, embodiments according to the present invention will be described with specific examples. In the present invention, the Langasite single crystal is used in a state where the crystal orientation is optimized as a material constituting the vibrator as described above. Here, an example will be described in which a tuning fork vibrator having two arm portions is formed of a langasite single crystal. FIG. 5 is a diagram for explaining the shape and vibration mode of a tuning fork vibrator, FIG. 5 (a) is a perspective view of the tuning fork vibrator, FIG. 5 (b) is in-plane vibration, and FIG. 5 (c). FIG. 4 is a diagram showing out-of-plane vibration.

  As described above, a tuning fork shape that can be designed to be relatively easy to support and have a low resonance frequency is selected as the vibrator shape, and functions as a tuning fork vibrator for a piezoelectric vibration gyro using two vibration modes. Here, the description will be given of a tuning fork shape having two arm portions, but the present invention can also be applied to a tuning fork shape having three or more arm portions.

  The operation principle will be described below. Based on the crystal orientation indicating the piezoelectricity of the selected piezoelectric single crystal material, an electrode coupled to the in-plane vibration mode and the out-of-plane vibration mode is arranged to form a tuning fork-type piezoelectric vibrator capable of excitation and detection, and in-plane vibration A drive signal having a frequency close to the mode resonance frequency is applied to the electrode to excite the in-plane vibration mode. In this state, when an angular velocity about the length direction of the vibrator is applied, a Coriolis force proportional to the angular velocity acts on the vibrator to generate an out-of-plane vibration mode.

  If an electric signal generated by this out-of-plane vibration mode is taken out from the electrode, an electric signal proportional to the angular velocity can be obtained and function as a piezoelectric vibration gyro. In this case, the in-plane vibration mode is used for the drive mode and the out-of-plane vibration mode is used for the detection mode, but these may be switched to use the out-of-plane vibration mode for the drive mode and the in-plane vibration mode for the detection mode. Is possible.

Based on the basic operating principle and configuration of the piezoelectric vibration gyro described above, in this embodiment, a langasite single crystal is used as the piezoelectric single crystal material, and an electromechanical coupling coefficient k ₁₂ is used to form one main surface. A tuning fork type piezoelectric vibrator with only electrodes formed therein was constructed. FIG. 1 is a perspective view schematically showing a tuning fork vibrator, FIG. 1 (a) is a tuning fork vibrator of the present invention in which the angle between the Y axis of the crystal axis and the principal surface is adjusted, and FIG. As a comparative example, a tuning fork type vibrator in which the Y axis of the crystal axis is prepared in parallel with the main surface. In FIG. 1, 11a and 11b are base parts, 12a and 12b are arm parts, and 13 is an electrode.

  Here, as shown in FIG. 1A, the tuning fork vibrator was prepared so that the angle formed between the Y axis of the crystal axis and the principal surface was −15 °. A vibration simulation using the finite element method was performed for this tuning fork vibrator. The X-axis, Y-axis, and Z-axis in the coordinate direction of the tuning fork vibrator are defined in directions 1 to 3 for convenience. In FIG. 1A, the electrodes 13 formed in the form of three strips on the main surface of each arm portion 12a are coupled to the in-plane vibration mode and the out-of-plane vibration mode. Functions as a component of the piezoelectric vibration gyro.

  It is more advantageous in manufacturing, assembly, and wiring that the belt-like electrode 13 is formed on the main surface on the same side of both arm portions 12a. Further, on the other main surface of each arm portion, three strip-shaped electrodes may be formed in parallel with the longitudinal direction of the arm portion 12a. Providing electrodes on both main surfaces of the arm portion reduces the productivity, but the driving and detection efficiencies are each doubled, enabling higher sensitivity.

  FIG. 2 is a perspective view showing a tuning fork vibrator in which three strip electrodes are formed on the main surface of the arm portion in the present embodiment. In FIG. 2, 21 is a base, 22a and 22b are arm portions, 23a and 23b are drive electrodes, 24a and 24b are detection electrodes, and 25a and 25b are reference potential electrodes.

  FIGS. 3A and 3B are diagrams for explaining vibration modes in the tuning fork vibrator according to the present embodiment. FIG. 3A shows an in-plane vibration mode, and FIG. 3B shows an out-of-plane vibration mode. . In this tuning fork vibrator, as shown in FIG. 3A, a drive voltage is applied between the drive electrodes 23a and 23b, the detection electrodes 24a and 24b, and the reference potential electrodes 25a and 25b. An electric field such as 3 (a) is generated. As a result, the left and right sides of the drive electrodes 23a and 23b in the drawing have opposite electric fields, so that one of the arm portions 22a and 22b expands in the longitudinal direction and the other contracts in the longitudinal direction.

  Therefore, the in-plane vibration mode can be excited by the drive electrodes 23a and 23b. Similarly, by applying a voltage having a phase opposite to that applied to the drive electrodes 23a and 23b between the drive electrodes 23a and 23b, the detection electrodes 24a and 24b, and the reference potential electrodes 25a and 25b, in-plane vibration The mode can be excited with twice the efficiency.

  Here, when an angular velocity is applied to the longitudinal axes of the arm portions 22a and 22b, an out-of-plane vibration mode based on Coriolis force is generated as shown in FIG. This vibration causes the left and right arms to be displaced in the opposite direction in the direction perpendicular to the main surface of the tuning fork vibrator. This vibration can be detected as a signal difference between the detection electrode 24a and the reference potential electrode 25a and between the detection electrode 24b and the reference potential electrode 25b.

  The signals of the detection electrodes 24a and 24b generated by the out-of-plane vibration mode have the same amplitude and the same phase. In the above description, the case where the piezoelectric vibration gyro is configured using the in-plane vibration mode as the drive mode and the out-of-plane vibration mode as the detection mode has been described, but the tuning fork is similarly applied when the drive mode and the detection mode are switched. It can be used as a shape oscillator.

  FIG. 4 is a block diagram showing a circuit configuration in the present embodiment. In FIG. 4, 40 is a tuning fork vibrator, 41 is a phase shift circuit, 42 is an adder circuit, 43 is a self-excited oscillation circuit, 44 is a synchronous detection circuit, 45 is a low-pass filter, 46a and 46b are operational amplifiers, 47a and 47b are A resistor, 48 is a reference potential, and 49 is an output section.

  Here, the signal output from the self-excited oscillation circuit 43 is applied to the drive electrode 23b, and the signal output from the self-excited oscillation circuit 43 is simultaneously applied to the drive electrode 23a by inverting the phase by the phase shift circuit 41. Then, the in-plane vibration mode is excited. The detection electrodes 24a and 24b are connected to a current detection circuit including an operational amplifier 46b and a resistor 47b, and an operational amplifier 46a and a resistor 47a.

  Thereby, the potentials of the detection electrodes 24a and 24b are fixed to the reference potential by the virtual ground of the operational amplifier. As a result, the detection electrodes 24a and 24b can generate a reference potential for applying a driving electric field simultaneously with the detection of the out-of-plane vibration mode. The outputs of the two current detection circuits are input to the adder circuit 42 and the self-excited oscillation circuit 43.

  The in-plane vibration mode components of the two signals input to the adder circuit 42 have opposite phases, and the out-of-plane vibration mode components have the same phase. Therefore, the signal input from the adder circuit 42 to the synchronous detection circuit 44 is only the out-of-plane vibration mode component generated by the Coriolis force proportional to the angular velocity, and the DC voltage output from the low-pass filter 45 is a voltage proportional to the angular velocity. Become.

  Therefore, it functions as an angular velocity sensor. The signal output from the self-excited oscillation circuit 43 is used as a reference signal for the synchronous detection circuit 44 at the same time as being fed back to the drive electrode 23 b and the phase shift circuit 41. Based on the above principle of operation, a tuning fork vibrator functioning as a component of a piezoelectric vibration gyro was simulated.

  Here, the tuning fork vibrator shown in FIG. 1A and the Langasite single crystal shown in FIG. 1B are arranged in a direction parallel to the principal plane of the Y axis of crystal orientation (hereinafter referred to as Z-cut and Note) A conventional tuning fork type vibrator was compared. The dimensions of this analysis model are as follows: the total length in the longitudinal direction is 5.2 mm, the thickness is 0.25 mm, the width of the base is 0.66 mm, the width of each arm is 0.22 mm, and the length of the arm is 3.2 mm. Thus, the resonance frequency of the in-plane vibration mode and the out-of-plane vibration mode is about 15 kHz.

  The evaluation item was the capacity ratio γ. The capacity ratio γ is an index indicating the conversion efficiency between the electric energy and the mechanical energy of the piezoelectric vibrator. The smaller the capacity ratio γ, the higher the efficiency, which is proportional to the reciprocal of the electromechanical coupling coefficient k. Table 4 shows changes in γ depending on the crystal orientation. Here, the relative value where γ of the conventional Z-cut piezoelectric vibrator is 100 is shown.

  Table 5 shows the change rate of the resonance frequency in each vibration mode. Here, the relative value with the resonance frequency of the Z-cut piezoelectric vibrator as 100 is shown.

  From the simulation results, the tuning fork vibrator configured by rotating the Y axis of the crystal orientation of the langasite single crystal by −15 ° about the X axis as the rotation axis is more than the conventional Z cut tuning fork vibrator. For γ and γ, the driving vibration mode and the detection vibration mode were about 10% better, respectively. Similarly, it was found that the resonance frequency was lowered by about 10%.

  In general, the SN ratio of a piezoelectric vibration gyro is proportional to the excitation efficiency in the drive vibration mode and the detection efficiency in the detection vibration mode, and inversely proportional to the drive frequency. The S / N ratio is improved as γ of the tuning fork vibrator is lower and as the driving frequency is lower. Therefore, the S / N ratio as a piezoelectric vibration gyro is about 30% when a tuning fork vibrator in which the Y axis of crystal orientation is rotated by −15 ° about the X axis is used rather than a conventional Z cut tuning fork vibrator. It can be said that it improves.

  As described above, the piezoelectric vibrating gyroscope using the tuning fork vibrator composed of the Langasite single crystal whose crystal orientation is rotated by −15 ° ± 10 ° about the X axis is the one using the conventional Z-cut tuning fork vibrator. In comparison, since the drive and detection efficiency can be improved and the resonance frequency of the tuning fork vibrator can be kept low, the circuit scale can be reduced.

  In addition, since etching can be performed due to the characteristics of the material itself, fine processing can be performed in any shape. Furthermore, since the speed of sound propagating in the single crystal is low, the tuning fork vibrator can be made small when designing a tuning fork vibrator having the same frequency. Therefore, according to the present invention, the tuning fork vibrator can be reduced in size as compared with the prior art, and the piezoelectric vibration gyro can be configured with a small circuit configuration.

  Although no specific example is shown, the same effect can be obtained even when an electrode is formed on the side surface of the tuning fork vibrator or only on one of the opposing main surfaces of the individual arm portions. can get. And this invention is not limited to the said embodiment, Even if there is a design change of the range which does not deviate from the summary of this invention, it is contained in this invention. That is, it goes without saying that various modifications and corrections that can be made by those skilled in the art are included.

The perspective view which shows the outline of a tuning fork type vibrator. FIG. 1A is a diagram showing a tuning fork vibrator in which the angle between the Y axis of the crystal axis and the principal surface is adjusted. FIG. 1B is a diagram showing a tuning fork vibrator in which the Y axis of the crystal axis is prepared in parallel with the main surface. The perspective view which shows the tuning fork type | formula vibrator which formed three strip | belt-shaped electrodes in the main surface of an arm part. 4A and 4B illustrate a vibration mode in the vibrator according to the present embodiment. FIG. 3A shows an in-plane vibration mode. FIG. 3B shows an out-of-plane vibration mode. FIG. 2 is a block diagram illustrating a circuit configuration in this embodiment. The figure explaining the shape and vibration mode of a tuning fork vibrator. FIG. 5A is a perspective view of a tuning fork vibrator. FIG. 5B shows in-plane vibration. FIG. 5C shows the out-of-plane vibration.

Explanation of symbols

11a, 11b, 21, 51 Base 12a, 12b, 22a, 22b, 52a, 52b Arm 13 Electrode 23a, 23b Drive electrode 24a, 24b Detection electrode 25a, 25b Reference potential electrode 40, 50 Tuning fork vibrator 41 Phase shift circuit 42 adder circuit 43 self-excited oscillation circuit 44 synchronous detection circuit 45 low-pass filters 46a and 46b operational amplifiers 47a and 47b resistor 48 reference potential 49 output section

Claims (4)

In a tuning fork vibrator in which a substantially rectangular parallelepiped base and a plurality of arms extending from one surface of the base are integrally formed of a piezoelectric single crystal, a surface parallel to a plane including the axes of the plurality of arms is provided. When the main surface and a surface substantially orthogonal to the main surface are side surfaces, a driving electrode, a detection electrode, and a reference potential electrode are formed on at least one of the main surface or the side surfaces, and the electrode between the electrodes is formed. A tuning fork for a piezoelectric vibration gyro that excites and detects in-plane vibration in a direction parallel to the main surface and out-of-plane vibration in a direction substantially perpendicular to the in-plane vibration by an electric field piezoelectric lateral effect in the thickness direction of the arm portion. In the resonator, the piezoelectric single crystal is a La ₃ Ga ₅ SiO ₁₄ single crystal, and the X-axis of the crystal orientation of the piezoelectric single crystal is substantially perpendicular to the main surface, and the crystal orientation of the piezoelectric single crystal is The angle between the Y axis and the side surface is -1. The piezoelectric vibrating gyro tuning fork oscillators, characterized in that ° is ± 10 °. In a tuning fork vibrator in which a substantially rectangular parallelepiped base and a plurality of arms extending from one surface of the base are integrally formed of a piezoelectric single crystal, a surface parallel to a plane including the axes of the plurality of arms is provided. When the main surface and a surface substantially orthogonal to the main surface are side surfaces, a driving electrode, a detection electrode, and a reference potential electrode are formed on at least one of the main surface or the side surfaces, and the electrode between the electrodes is formed. A tuning fork for a piezoelectric vibration gyro that excites and detects in-plane vibration in a direction parallel to the main surface and out-of-plane vibration in a direction substantially perpendicular to the in-plane vibration by an electric field piezoelectric transverse effect in the width direction of the arm portion. In the vibrator, the piezoelectric single crystal is a La ₃ Ga ₅ SiO ₁₄ single crystal, and an X axis of a crystal orientation of the piezoelectric single crystal is substantially orthogonal to a plurality of arm portions of the tuning fork vibrator, Y axis of crystal orientation of single crystal and front The piezoelectric vibrating gyro tuning fork oscillators, characterized in that the angle main surface forms is -15 ° ± 10 °. An axis of the two arm portions in a tuning fork vibrator in which a substantially rectangular parallelepiped base portion, a first arm portion and a second arm portion extending from one surface of the base portion are integrally formed of a piezoelectric single crystal When the surface parallel to the plane to be included is the main surface, the first electrode and the second electrode are sequentially formed on the same main surface of the first arm portion and the second arm portion from the side closer to the other arm portion. The third electrode is formed in parallel with the longitudinal direction of the arm portion, is parallel to the main surface, and is parallel to the main surface by a piezoelectric lateral effect caused by an electric field in a direction perpendicular to the longitudinal direction of the arm portion. In a tuning fork vibrator for a piezoelectric vibration gyro that excites and detects in-plane vibrations in various directions and out-of-plane vibrations in a direction substantially perpendicular to the in-plane vibrations, the piezoelectric single crystal is La ₃ Ga ₅ SiO ₁₄ single The X-axis of the crystal orientation of the piezoelectric single crystal is A piezoelectric vibrating gyroscope characterized in that an angle formed between a Y axis of a crystal orientation of the piezoelectric single crystal and the principal surface is −15 ° ± 10 ° substantially perpendicular to a plurality of arms of the tuning fork vibrator. Tuning fork type vibrator. An axis of the two arm portions in a tuning fork vibrator in which a substantially rectangular parallelepiped base portion, a first arm portion and a second arm portion extending from one surface of the base portion are integrally formed of a piezoelectric single crystal When a surface parallel to a plane including the main surface is a main surface, one main surface of the first arm portion, and a main surface on the opposite side of the second arm portion, sequentially from the side closer to the other arm portion, The first electrode, the second electrode, and the third electrode are formed in parallel to the longitudinal direction of the arm portion, and are parallel to the main surface, and the piezoelectric lateral effect due to an electric field in a direction perpendicular to the longitudinal direction of the arm portion. In the tuning fork vibrator for a piezoelectric vibration gyro that excites and detects in-plane vibration in a direction parallel to the main surface and out-of-plane vibration in a direction substantially perpendicular to the in-plane vibration, the piezoelectric single crystal includes: a la ₃ Ga ₅ SiO ₁₄ single crystal, the piezoelectric single crystal The X axis of the crystal orientation is substantially perpendicular to the plurality of arm portions of the tuning fork vibrator, and the angle formed between the Y axis of the crystal orientation of the piezoelectric single crystal and the main surface is −15 ° ± 10 °. A tuning-fork vibrator for a piezoelectric vibratory gyro.

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