JP2003014464A - Vibration gyro and its adjusting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration gyro and its adjusting method capable of adjusting a resonance frequency without processing a vibrator directly. SOLUTION: This gyro is equipped with a piezoelectric element 1 having a beam part 11 and a support part 12, a base 2 where the support part 12 is fixed, and processable frequency adjusting parts 3, 4. The processable frequency adjusting parts 3, 4 are bonded and fixed onto the support part 12 and the base 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration gyro and a method for adjusting a vibration gyro for correcting a camera shake of a video camera or a digital still camera, or for detecting an angular velocity used for posture control of a vehicle, calculation of a traveling direction, and the like. Is.

[0002]

2. Description of the Related Art Conventionally, various gyros have been developed as sensors for detecting angular velocity. The types are roughly
Mechanical coma gyro, fluid type gas rate gyro,
It is classified into a vibration gyro that uses the vibration of a tuning piece and a tuning fork, an optical fiber gyro, and a ring laser gyro. The optical gyro detects the Sagnac effect, and the others use the Coriolis force, which is a manifestation of the law of conservation of angular momentum of the rotating body, to detect the angular velocity. Which gyro is selected is determined in consideration of accuracy, price, size, etc. suitable for the intended use.

For example, in Japanese Patent No. 2780643,
A quadrangular prismatic vibrating gyro is disclosed. The vibrator of this gyro is a quadrangular prism sound piece of a bimetal structure using a piezoelectric substrate, and electrodes are formed on the main surface of the piezoelectric body. The electrode on one side is used as a common electrode, and the other electrode is divided and used as a driving / detecting electrode.

Driving is performed by applying a drive voltage from an oscillation circuit to a drive / detection electrode through a load resistor to excite drive vibration. On the other hand, the Coriolis force Fc is expressed as Fc = 2mv × Ω, where m is the mass, v is the vibration velocity, and Ω is the rotational angular velocity. In this case, since the rotation axis is set in the long axis direction of the prism, the Coriolis force Fc is generated in the direction perpendicular to the driving vibration and parallel to the prism cross section. The Coriolis force Fc is calculated by amplifying the difference between the charges generated in the divided electrodes.

Further, as another example, Japanese Patent Laid-Open No. 10-325.
Japanese Patent No. 727 discloses a triangular prismatic piece gyro. In this patent, the oscillator is made of a constant elastic metal such as elinvar, and a piezoelectric substance is bonded onto the oscillator to excite drive vibration through a load resistor. The method of detecting the Coriolis force and using the load resistance is the same as in Japanese Patent No. 2780643.

A method of adjusting the vibration gyro is disclosed in, for example, Japanese Patent Laid-Open No. 10-325727. In this patent, the vibration balance of the vibrator is adjusted by cutting the edge of the vibrator to adjust the phase difference between the output caused by the Coriolis force and the other output to be 90 °. Further, in Japanese Patent No. 2558977, a concavo-convex portion is formed along the longitudinal direction of the vibrator at the widthwise center of the side surface of the vibrator to adjust the resonance frequency. Furthermore, JP-A-1
Japanese Patent Laid-Open No. 0-103961 discloses a method of adjusting temperature characteristics by trimming an electrode portion in a square-column vibrating piece vibrating gyro using a piezoelectric vibrator.

[0007]

Adjustment is indispensable in order to improve the production yield of the vibration gyro and reduce the price. However, in the conventional technique, the adjustment of the vibration gyro requires a direct physical processing operation such as cutting or adding a mass to the vibrator itself. However, this always included the possibility of degrading the characteristics of the vibrator, and was not an appropriate adjustment method.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration gyro that can adjust the resonance frequency without directly processing the vibrator and a method for adjusting the vibration gyro.

[0009]

A vibrating gyroscope according to the present invention comprises a piezoelectric element having a beam portion and a supporting portion, a base to which the supporting portion is fixed, and a frequency adjusting portion capable of being processed. The frequency adjusting unit is adhesively fixed to the supporting unit and the base. Accordingly, the resonance frequency of the vibration gyro can be adjusted by processing the frequency adjusting unit without processing the piezoelectric element that is the vibrator. Therefore, variations in sensitivity can be reduced without lowering the measurement accuracy of the vibration gyro, and the yield can be improved.

Preferably, the beam portion is formed by laminating two flat plate piezoelectric bodies in a bimorph type so that their polarization axes are opposed to each other, and the supporting portion is at least the front and back main surfaces of the beam portion. It is formed on one side. Thereby, the vibration can be driven and the rotational angular velocity can be obtained by using the Coriolis force.

[0011] Preferably, at least two frequency adjusting sections form one set, and the frequency adjusting sections are symmetrically bonded and fixed to the supporting section in a set. Thereby, the balance of the vibration direction is good, and the resonance frequency can be easily adjusted.

Further, preferably, the material of the frequency adjusting section is metal or ceramics. Thereby,
Since good vibration can be obtained, highly accurate measurement can be performed.

Further, in the vibration gyro adjusting method of the present invention, the piezoelectric element having the beam portion and the supporting portion, the base to which the supporting portion is fixed, and the supporting portion and the base are bonded and fixed. A frequency adjusting unit, wherein the beam portion is a method of adjusting a vibration gyro having at least two resonance vibration modes in which vibration directions are substantially orthogonal, by changing the shape of the frequency adjusting unit, The contact area between the supporting part and the frequency adjusting part is changed to adjust the frequency difference between the resonance vibration modes. As a result, it is not necessary to process the piezoelectric element that is the vibrator, so that the frequency difference can be easily adjusted without lowering the measurement accuracy.

Further, in another vibration gyro adjusting method of the present invention, a piezoelectric element having a beam portion and a supporting portion, a base to which the supporting portion is fixed, and an adhesive fixing to the supporting portion and the base. A method of adjusting a vibrating gyroscope, wherein the beam part has at least two resonance vibration modes in which vibration directions are substantially orthogonal to each other, and a material of the frequency adjuster is changed. Thus, the mass density of the frequency adjusting unit is changed to adjust the frequency difference between the resonance vibration modes.

Further, in another vibration gyro adjusting method of the present invention, a piezoelectric element having a beam portion and a supporting portion, a base to which the supporting portion is fixed, and an adhesive fixing to the supporting portion and the base. A method of adjusting a vibrating gyroscope, wherein the beam portion has at least two resonance vibration modes in which vibration directions are substantially orthogonal to each other. On the adhesive surface of, a plurality of regularly arranged adjustment pieces that are adhesively fixed to the support portion are formed, and by cutting the adjustment pieces from the frequency adjustment portion by cutting, respective frequencies of the resonance vibration modes are obtained. The difference is being adjusted. Thereby, the frequency difference can be adjusted discretely.

Preferably, the adjusting piece is separated from the frequency adjusting section by laser processing.

Another vibration gyro adjusting method of the present invention is a piezoelectric element having a beam portion and a supporting portion, a base to which the supporting portion is fixed, and an adhesive fixing to the supporting portion and the base. A method for adjusting a vibrating gyroscope, wherein the beam part has at least two resonance vibration modes in which vibration directions are substantially orthogonal to each other, and a cut is made in the frequency adjuster by laser processing. By performing the adjustment, the frequency difference between the resonance vibration modes or the balance in the vibration direction of the resonance vibration modes is adjusted. As a result, the frequency difference or the balance in the vibration direction can be adjusted without processing the piezoelectric element that is the vibrator.
The frequency difference or the balance in the vibration direction can be easily adjusted without lowering the measurement accuracy.

Preferably, the notch of the frequency adjusting section is formed by cutting.

Further, preferably, at least two of the frequency adjusting sections are a set, and the frequency adjusting sections are symmetrically bonded and fixed to the supporting section in a set. Thereby, the balance in the vibration direction is good, and the frequency difference or the balance in the vibration direction can be easily adjusted.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A vibration gyroscope and a method of adjusting the same according to a first embodiment of the present invention will be described with reference to the drawings. Note that the same reference numerals are given to the same parts throughout the drawings.

FIG. 1 is a perspective view showing the structure of a vibrating gyroscope according to the first embodiment of the present invention. The main components of the vibrating gyroscope according to the first embodiment are the piezoelectric element 1 which is a vibrator, the base 2, and the frequency adjusting units 3 and 4. As shown in the figure, the longitudinal direction of the piezoelectric element 1 is the X axis, the left-right direction when viewed from the X-axis direction is the Y axis, and the vertical direction is the Z axis. It is assumed that these coordinate axes are the same in the drawings in which the piezoelectric element is shown.

First, the structure of the piezoelectric element 1 will be described with reference to the drawings. FIG. 2 is a perspective view showing the configuration of the piezoelectric element of the present invention. The piezoelectric element 1 has a bimorph structure in which two lithium niobate (LiNbO ₃ ) substrates 101 and 102, which are piezoelectric single crystal substrates, are bonded by direct bonding so that their polarization directions face each other.

The piezoelectric element 1 has a beam portion 11 of a square pole piece type.
And a supporting portion 12 fixed to the base 2 or the frequency adjusting portions 3 and 4. The drive / detection electrodes 103 and 104 and the shared electrode 10 are provided on the front and back main surfaces of the beam 11.
5 are formed on each surface. The drive / detection electrodes 103 and 104 are formed on the same surface. These driving / detecting electrodes 103 and 104 and the common electrode 10
By applying an appropriate AC drive voltage between the beams 5,
The driving vibration of No. 1 is excited. The drive vibration is excited in the Z-axis direction, and the Coriolis force appears as vibration in the Y-axis direction.
Note that in FIG. 2, the thicknesses of the drive / detection electrodes 103 and 104 and the shared electrode 105 are exaggerated for the sake of clarity. In reality, it is not this thick. The support portion 12 is formed on at least one of the front and back main surfaces of the beam portion 11.

To bond the piezoelectric single crystal substrates to each other in the production of the piezoelectric element 1, the direct bonding is used as described above. Here, the principle of direct bonding will be described with reference to FIG. FIG. 3 is a schematic diagram for explaining the principle of direct joining.
3A, 3B, and 3C are in the order of steps of direct bonding. 106 and 107 are piezoelectric single crystal substrates. L1 and L in FIGS. 3A, 3B, and 3C
2, L3 indicates the distance between the substrates 106 and 107,
The relationship of L1>L2> L3 is established. Both surfaces of the piezoelectric single crystal substrates 106 and 107 are mirror-polished.

First, as shown in FIG. 3 (a), the substrates 106 and 107 are first subjected to a hydrophilic treatment, and then the substrates 106 and 1 are made hydrophilic.
The 07 surface is terminated with a hydroxyl group (OH group). Next, FIG.
As shown in (b), the two substrates 1 subjected to hydrophilic treatment
06 and 107 are attached to each other so that their polarization axes face each other. Then, the two substrates 106 and 107 are attracted to each other by an attractive force such as hydroxyl group polymerization or hydrogen bond to be bonded. Finally, by heat-treating the two substrates 106 and 107, as shown in FIG.
The constituent atoms of 7 are covalently bonded via the oxygen atom (O), and the direct bonding is completed.

In the direct bonding, since the substrates 106 and 107 are bonded at the atomic level without an adhesive layer interposed therebetween, the bonding strength is high and there is no energy loss in the adhesive layer. for that reason,
This is one of the joining methods suitable for the vibration gyro that positively uses the resonance effect.

Next, a method for producing the piezoelectric element 1 will be described with reference to FIG. FIG. 4 is an explanatory diagram of a process for producing the piezoelectric element of the present invention. 4 (a), (b), (c),
(D) and (e) are arranged in the order of steps.

First, as shown in FIG. 4A, the substrate 10
6, 107 are directly bonded by the above-described method so that the polarization axes face each other. For example, 106 and 107 are piezoelectric single crystal lithium niobate substrates (140 ° rotated Y plate), and the thickness of each of the substrates 106 and 107 is 350 μm.
m and 1050 μm.

Next, as shown in FIG. 4B, the thicker substrate 107 side is ground to form a concave groove 108 in the substrate 107. Next, as shown in FIG.
A metal electrode 109 is formed on the substrate 106. Note that FIG.
Substrates 106 and 107 shown in FIG.
The substrates 106 and 107 of (b) are shown inverted. For forming the electrode 109 on the substrate 106 side, for example, Au--
After the Cr electrode is formed over the entire surface by sputtering, pattern formation is performed by a technique such as lift-off or etching. Electrode 10
As shown in FIG. 4C, 9 has a rectangular shape formed at equal intervals. The position where the electrode 109 is formed is
It is determined in consideration of the structure when each piezoelectric element 1 is completed. At this time, the alignment with the groove 108 on the back surface is required, and a double-sided aligner may be used for that.

Although not shown, an Au-Cr electrode is formed on the entire surface of the substrate 107 side. Further, since the groove 108 is formed on the substrate 107 side, it is difficult to apply the photolithography technique. Therefore, the electrodes are formed by a method such as sputtering or vapor deposition using a stencil mask.

Next, the substrates 106 and 107 are attached to each piezoelectric element 1.
Split into. As shown in FIG. 4D, each piezoelectric element 1 is divided along a dividing line 110 with a dicing saw.
Cut out. As shown in FIG. 4E, the piezoelectric element 1 is created.

The piezoelectric element 1 produced by the above-described method is set on the base 2, and the bottom surface and the back surface of the supporting portion 12 are fixed to the base 2 with an adhesive. When a metal having a high specific gravity, such as brass, is used as the material of the base 2, the supporting portion 12 is firmly fixed, so that the measurement accuracy is high. Other than that, it is preferable to use ceramics having temperature characteristics similar to those of the piezoelectric element 1. As the adhesive, for example, an epoxy adhesive is used.

The frequency adjusting portions 3 and 4 are fixed to the side surface of the supporting portion 12 of the piezoelectric element 1 with an adhesive agent, and are also fixed to the base 2 with an adhesive agent on the back surface and the bottom surface. The frequency adjusting parts 3 and 4 are cubic shapes having the same cross-sectional area as the supporting part 12 of the piezoelectric element 1. As the material, the same material as the base 2 (for example, a metal having a high specific gravity such as brass or a ceramic having a temperature characteristic close to that of a piezoelectric element) is used.

The electrodes formed on the piezoelectric element 1 are the driving / detecting electrodes 103 and 104 and the common electrode 105. These electrodes 103, 104 and 105 are the drive / detection combined electrodes 203 and 204 and the common electrode 20 provided on the base 2.
It is connected to 5. Although not shown, the electrodes of the base 2 are connected to a drive detection circuit and exchange signals for drive and detection.

FIG. 5 is a perspective view for explaining a vibrating gyro adjusting method according to the first embodiment of the present invention.
FIG. 5A shows the configuration of a vibrating gyroscope in which the frequency adjusting unit is not installed. As shown in FIG. 5A, even if the back surface and the bottom surface of the supporting portion 12 are simply adhered to the base 2 without using the frequency adjusting portions 3 and 4, it can be used as a vibration gyro.

Next, a method of adjusting the vibration gyroscope according to the first embodiment will be described. Generally, in the vibration gyro, in order to improve the sensitivity, the resonance frequencies of the two resonance vibration modes in the Z direction (driving vibration direction) and the Y direction (vibration direction by Coriolis force) in the vibration gyro are set to be as close as possible. For example, a detuning degree (a value obtained by dividing the difference between two resonance frequencies by one resonance frequency) is used as an index indicating the closeness of the resonance frequencies. The smaller the degree of detuning, that is, the closer the two resonance frequencies are, the larger the amplitude due to the Coriolis force and the better the sensitivity.

In the vibrating gyro, the fixed state of the support 12 affects the resonance frequency of the piezoelectric element 1. In the vibrating gyro, it is necessary to fix a part of the piezoelectric element 1 which is the vibrator, but as the fixing area of the vibrator becomes larger, the fixed state of the piezoelectric element 1 which is the vibrator influences the resonance vibration mode. Exert.

The two resonance frequencies change depending on the fixed state. Therefore, the detuning degree also changes. That is, the degree of detuning can be changed by changing the fixed state. When the shapes of the frequency adjusting units 3 and 4 are changed, the contact areas between the frequency adjusting units 3 and 4 and the supporting unit 12 are changed, and the fixed state is changed. Therefore, the shapes of the frequency adjusting units 3 and 4 should be changed. Thus, the detuning degree can be set to a desired value.

FIG. 5B shows the structure of a vibrating gyro in which the shape of the frequency adjusting section is changed. The vibrating gyro of FIG. 5B is the frequency adjusting unit 3 of the vibrating gyro of FIG.
As compared with 4, the piezoelectric element 1 is fixed by using the frequency adjusting portions 31 and 41 which are lower in height. Even with a vibration gyro whose detuning degree deviates from the specified value due to processing variations, the detuning degree can be adjusted and kept within the specified value by using the low-frequency adjusting units 31 and 41. That is, by appropriately changing the shapes of the frequency adjusting units 3 and 4, it is possible to change the fixed state of the piezoelectric element 1 and adjust the detuning degree of the vibration gyro within a specified value.

Here, the change in the detuning degree of the vibration gyroscope according to the first embodiment will be described using actual measurement results. Figure 10
FIG. 6 is a diagram showing the relationship between the height of the frequency adjustment unit and the degree of detuning. This is the measurement result of the degree of detuning when one of the frequency adjusting units is left as it is and the depth and width of one of the frequency adjusting units are kept constant and only the height is changed. As can be seen from FIG. 10, the detuning degree is changed by changing the height of one frequency adjusting section.

FIG. 11 is a diagram showing the relationship between the width of the frequency adjusting section and the degree of detuning. This is the measurement result of the degree of detuning when one of the frequency adjusting units is left unchanged and one of the frequency adjusting units has the same height and depth and only the width (Y direction) is changed. As can be seen from FIG. 11, the detuning degree is changed by changing the width of one frequency adjusting unit.

It can be seen from FIGS. 10 and 11 that the detuning degree is changed by changing the shape of the frequency adjusting section. Although the degree of change of the detuning degree is different between FIG. 10 and FIG. 11, it can be seen that the detuning degree is changed not only by changing the height of the frequency adjusting unit but also by changing the width, and the vibration gyro can be adjusted. .

As described above, according to the vibrating gyroscope and the adjusting method thereof according to the first embodiment, the shapes of the frequency adjusting portions 3 and 4 to which the piezoelectric element 1 is adhered and fixed are changed to change the shape of the piezoelectric element 1. Since the fixed state is changed to adjust the detuning degree, it is possible to adjust the detuning degree to a desired value without processing the piezoelectric element 1 which is the vibrator. As a result, even with a vibration gyroscope whose detuning degree is outside the allowable range, the detuning degree can be adjusted within the allowable range, so that the production yield can be improved.

(Second Embodiment) A vibrating gyroscope and a method of adjusting the same according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a perspective view showing the configuration of the vibrating gyroscope according to the second embodiment. The basic configuration of the vibration gyro of the second embodiment is the same as that of the vibration gyro of the first embodiment. The difference is that the fixed state of the piezoelectric element is not changed by changing the height or width of the frequency adjustment section, but the fixed state of the piezoelectric element is changed by making a notch in the frequency adjustment section to change the detuning degree. Is the point to adjust.

The structure of the vibration gyro shown in FIG. 6A will be described. The piezoelectric element 1 is installed on the base 2 and fixed by the frequency adjusting units 3 and 4. Frequency adjustment unit 3,
A notch 51 having a predetermined depth is vertically formed in the base 4 and the base 2 with a dicing saw along the X-axis direction.

The notch 51 weakens the fixed state of the upper portion of the piezoelectric element 1 and changes the detuning degree. The detuning degree can be adjusted within the range of the specified value by appropriately making the cuts 51 in the frequency adjusting units 3 and 4. The notch 51 may be provided in the frequency adjusting units 3 and 4, and may not be provided in the base 2. However, when processing is performed after fixing the frequency adjusting units 3 and 4 on the base 2, a dicing saw is used to cut only the frequency adjusting units 3 and 4.
Since it is difficult to provide the base 1, the base 2 is machined as shown in FIG. If laser processing is used, only the frequency adjusting units 3 and 4 can be processed.

Further, in the vibration gyro of FIG. 6B, the frequency adjusting portions 32 and 42 have grooves formed on the surfaces to be bonded to the piezoelectric elements 1 at regular intervals using a dicing saw. A plurality of adjustment pieces 301 are formed. FIG. 7 is a perspective view showing the configuration of the frequency adjusting unit.
FIG. 7A shows the frequency adjusting unit 32 (42) of the vibration gyro of FIG. 6B.

The frequency adjusting unit 32 (42) in FIG. 7 (a)
Is formed by forming grooves in the vertical direction at regular intervals on the surface of the piezoelectric element 1 that is adhered to the supporting portion, and then forming grooves in the horizontal direction at regular intervals so that the constant intervals are provided in the vertical and horizontal directions. In addition, the regularly arranged adjustment pieces 301 are formed. In addition,
In FIG. 7A, the adjustment piece 301 is formed only on the upper surface of the bonding surface with the piezoelectric element 1 and not on the entire surface. It doesn't matter.

As shown in FIG. 6B, the frequency adjusting section 3
When 2 and 42 are bonded to the piezoelectric element 1, the adjustment pieces 301 and the supporting portion of the piezoelectric element 1 are bonded. Similar to FIG. 6A, a cut 52 having a predetermined depth is vertically formed in the frequency adjusting units 32 and 42 in the X-axis direction. At this time, the notch 52 causes the adjustment piece 301 to move to the frequency adjustment sections 32, 42.
To be disconnected from. Since the adjustment pieces are regularly arranged, the fixed state changes discretely depending on the number and position of the adjustment pieces 301 to be separated. That is, the detuning degree can be adjusted discretely. Since each of the desired adjustment pieces 301 must be cut, the cut 52 is made by laser processing that can surely perform processing at a desired position.

FIG. 7B shows another example of the frequency adjusting section. As shown in FIG. 7B, the shape of the adjustment pieces 302 may be a plate shape as long as they are regularly arranged.

As described above, according to the vibrating gyroscope and the method of adjusting the same according to the second embodiment, the notch 51 is formed in the frequency adjusting portions 3 and 4 to which the piezoelectric element 1 is adhesively fixed so that the piezoelectric element 1 can be made. Since the fixed state is changed and the detuning degree is adjusted, the detuning degree can be adjusted to a desired value without processing the piezoelectric element that is the vibrator. As a result, even with a vibration gyroscope whose detuning degree is outside the allowable range, the detuning degree can be adjusted within the allowable range, so that the production yield can be improved.

(Third Embodiment) A vibrating gyroscope and a method of adjusting the same according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a perspective view showing the configuration of the vibrating gyroscope according to the third embodiment. The basic configuration of the vibrating gyroscope of the third embodiment is the same as that of the vibrating gyroscope of the first embodiment. The difference is that the fixed state of the piezoelectric element is not changed by changing the height or width of the frequency adjustment section, but the fixed state of the piezoelectric element is changed by making a horizontal cut in the frequency adjustment section. is there. Also, the vibration balance is adjusted instead of adjusting the detuning degree of the vibration gyro.

The structure of the vibration gyro shown in FIG. 8 will be described. The piezoelectric element 1 is installed on the base 2 and fixed by the frequency adjusting units 3 and 4. A notch 53 having a predetermined depth in the horizontal direction is made by a dicing saw in the lower portion of the frequency adjusting units 3 and 4 along the X-axis direction. With the notch 53, the vibration balance of the vibration gyro can be adjusted.

Here, the adjustment of the vibration balance is to prevent the vibration direction from shifting. In the vibration gyro shown in FIG. 8, the vibration mode in the Z-axis direction is used as drive vibration. This deviation in the vibration direction directly leads to an increase in noise of the detection signal. Therefore, it is necessary to adjust the balance so that the vibration direction does not shift.

By making a horizontal cut 53 in the frequency adjusting portions 3 and 4, the fixed state of the piezoelectric element 1 in the Y-axis direction changes. Since the deviation in the vibration direction is a component in the Y-axis direction, the vibration balance can be adjusted by appropriately making the cuts 53 in the frequency adjusting units 3 and 4.

As described above, according to the vibrating gyroscope and the adjusting method thereof according to the third embodiment, the piezoelectric element 1 is formed by appropriately making the cuts 53 in the frequency adjusting portions 3 and 4 to which the piezoelectric element 1 is adhered and fixed. Since the fixed state is changed to adjust the vibration balance of the piezoelectric element 1, the vibration balance can be adjusted without processing the piezoelectric element that is the vibrator. As a result, the vibration direction does not shift, the increase of noise due to the error of the vibration axis is prevented, the S / N ratio of Coriolis force detection is improved, and high quality measurement can be performed.

In the third embodiment, the vicinity of the bonding surface between the frequency adjusting units 3 and 4 and the base 2 is processed by laser. However, it is not necessary to process the vicinity of the base 2, and the frequency adjusting unit is not necessary. Any part of 3 and 4 may be processed. Also,
It is not necessary to limit to laser processing, and there is no problem in cutting processing.

In the vibrating gyroscope according to the embodiment of the present invention, the piezoelectric element serving as a vibrator is of the cantilever beam type in which a piezoelectric single crystal has a bimorph structure. This is a piezoelectric ceramic. Any piezoelectric element having a structure in which the beam portion and the support portion are formed separately and the support portion can be fixed not by a point but by a surface may be used. Also, even if the structure is one in which a constant elastic metal such as elinvar is used as the material of the vibrator and a piezoelectric flat plate is attached to the surface thereof, it is sufficient if it has a beam portion and a support portion that can be fixed by the surface. .

Further, the piezoelectric element may have a shape other than the cantilever beam type, and the supporting portion may be formed on both sides of the main surface of the beam, and the width of the supporting portion is different from that of the beam portion. There is no problem. Further, even in the tuning fork type, if the piezoelectric element has a supporting portion that can be fixed on the surface, the same effect as in the tuning piece type can be obtained.

FIG. 9 shows the structure of a vibrating gyroscope of a flat plate type base, but the shape of the base is not limited to the L type base 2 as shown in FIG. A flat plate type base 21 or base 22 as shown in FIG. 9A or FIG. 9B may be used. Further, the shape of the frequency adjusting unit does not have to be limited to a cube, and the optimum shape may be set based on the shapes of the base and the vibrator. For example, an L-shaped structure such as the frequency adjusting portions 33 and 43 shown in FIG. 9A may be used to fix the entire side surface of the supporting portion of the piezoelectric element 1.

Further, the number of frequency adjusting sections does not have to be a set of two, and the piezoelectric elements may be installed as many as the number of side surfaces to which the piezoelectric element can be fixed, or only one specific surface can be provided by one frequency adjusting section. You may fix it. Further, as a material of the frequency adjusting section, in order to improve the fixed state of the piezoelectric element, a material having a heavy mass is desirable, and a metal such as brass is preferable. Further, since better vibration can be obtained when the temperature characteristics are closer to those of the piezoelectric element, ceramics whose temperature characteristics are closer to those of the material used for the piezoelectric element may be used.

Although the adjustment effect is strong or weak, the detuning degree can be adjusted by changing the mass density of the material of the frequency adjusting section (for example, changing ceramics to metal).

[0063]

As described above, according to the vibration gyro and the adjusting method thereof of the present invention, the piezoelectric element having the beam portion and the supporting portion, the base to which the supporting portion is fixed, the supporting portion and the base are provided. Since the vibration gyro is adjusted by processing the frequency adjustment unit, the frequency adjustment unit is fixedly bonded to the and, so that the frequency adjustment unit can be processed without processing the piezoelectric element that is the vibrator. You can adjust the gyro. for that reason,
Variation in sensitivity can be reduced without lowering accuracy, and yield can be improved.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a configuration of a piezoelectric element of the present invention.

3A and 3B are schematic diagrams for explaining the principle of direct bonding, and FIG. 3A is a cross-sectional view showing a first step of direct bonding.
FIG. 3B is a sectional view showing the second step of direct bonding, and FIG.
Is a sectional view showing the third step of the direct bonding.

4A and 4B are explanatory views of a process for producing a piezoelectric element of the present invention, FIG. 4A is a perspective view showing a first process, FIG. 4B is a perspective view showing a second process, and FIG. 4D is a perspective view showing the third step, FIG. 4D is a plan view showing the fourth step, and FIG.
Shows the 5th step

FIG. 5 is a perspective view for explaining the method of adjusting the vibration gyroscope according to the first embodiment of the present invention, and FIG.
Is a perspective view showing the configuration of a vibration gyro without a frequency adjustment unit installed, and FIG. 5B is a perspective view showing the configuration of a vibration gyro with the shape of the frequency adjustment unit changed.

FIG. 6 is a perspective view showing a configuration of a vibrating gyroscope according to a second embodiment of the present invention, and FIG. 6A is a perspective view showing a configuration of a vibrating gyroscope provided with a frequency adjusting unit having no adjusting piece; FIG.6 (b) is a perspective view which shows the structure of the vibration gyro provided with the frequency adjustment part which has an adjustment piece.

FIG. 7 is a perspective view showing a frequency adjusting unit of the vibration gyroscope according to the second embodiment of the present invention, and FIG.
FIG. 7B is a perspective view showing a frequency adjusting unit installed in the vibration gyro, and FIG. 7B is a perspective view showing another example of the frequency adjusting unit.

FIG. 8 is a perspective view showing a configuration of a vibrating gyroscope according to a third embodiment of the present invention.

9A and 9B are perspective views showing another example of the vibration gyro of the present invention, FIG. 9A is a perspective view showing the structure of the vibration gyro of the first flat plate base, and FIG. The perspective view which shows the structure of the vibration gyro of the flat plate type base of FIG.

FIG. 10 is a diagram showing the relationship between the height of the frequency adjustment unit and the degree of detuning.

FIG. 11 is a diagram showing the relationship between the width of the frequency adjustment unit and the degree of detuning.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Piezoelectric element 11 Beam part 12 Support part 105 Shared electrode 108 Groove 109 Metal electrode 110 Dividing line 2, 21, 22 Base 3, 4, 31, 32, 33, 41, 42, 43 Frequency adjusting part 51, 52 Notch 101 , 102 piezoelectric single crystal substrates 103, 104 drive / detection combined electrodes 106, 107 piezoelectric single crystal lithium niobate substrates

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takafumi Koike             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 2F105 AA02 AA08 BB15 CC04 CD02                       CD06 CD13 CD20

Claims (11)

[Claims] 1. A piezoelectric element having a beam portion and a supporting portion, a base to which the supporting portion is fixed, and a frequency adjusting portion capable of being processed, the frequency adjusting portion including the supporting portion. A vibrating gyro, which is fixedly bonded to the base. 2. The beam portion is formed by laminating two flat plate piezoelectric bodies in a bimorph type so that their polarization axes are opposed to each other, and the supporting portion is at least one of front and back main surfaces of the beam portion. The vibrating gyro according to claim 1, wherein 3. The frequency adjusting unit is a set of at least two frequency adjusting units and is symmetrically bonded and fixed to the supporting unit in a pair.
Vibration gyro described in. 4. The vibrating gyroscope according to claim 1, wherein a material of the frequency adjusting unit is metal or ceramics. 5. A piezoelectric element having a beam portion and a support portion, a base to which the support portion is fixed, and a frequency adjusting portion that is adhesively fixed to the support portion and the base, the beam portion Is a method of adjusting a vibration gyro having at least two resonance vibration modes in which the vibration directions are substantially orthogonal to each other, and by changing the shape of the frequency adjusting unit, the supporting unit and the frequency adjusting unit are A method for adjusting a vibration gyro, wherein a contact area is changed to adjust a frequency difference between the resonance vibration modes. 6. A piezoelectric element having a beam portion and a supporting portion, a base to which the supporting portion is fixed, and a frequency adjusting portion that is adhesively fixed to the supporting portion and the base of the piezoelectric element. ,
The beam part is a method of adjusting a vibration gyro having at least two resonance vibration modes in which vibration directions are substantially orthogonal to each other, wherein a mass density of the frequency adjustment part is changed by changing a material of the frequency adjustment part. Is adjusted to adjust the frequency difference between the resonance vibration modes, thereby adjusting the vibration gyro. 7. A piezoelectric element having a beam portion and a support portion, a base to which the support portion is fixed, and a frequency adjusting portion that is adhesively fixed to the support portion and the base of the piezoelectric element. ,
The beam part is a method of adjusting a vibrating gyroscope having at least two resonance vibration modes in which vibration directions are substantially orthogonal to each other, and the supporting part is provided on a surface of the frequency adjusting part that is adhered to the supporting part. A plurality of regularly arranged adjustment pieces that are adhesively fixed to each other are formed, and the adjustment pieces are separated from the frequency adjustment unit by cutting, thereby adjusting the respective frequency differences of the resonance vibration modes. How to adjust the vibration gyro. 8. The adjusting piece is separated from the frequency adjusting section by laser processing.
The method of adjusting the vibration gyro described in. 9. A piezoelectric element having a beam portion and a supporting portion, a base to which the supporting portion is fixed, and a frequency adjusting portion that is adhesively fixed to the supporting portion and the base of the piezoelectric element. ,
The beam part is a method of adjusting a vibration gyro having at least two resonance vibration modes in which vibration directions are substantially orthogonal to each other. A method of adjusting a vibration gyro, comprising adjusting the respective frequency differences or the balance of the vibration directions of the resonance vibration modes. 10. The method of adjusting a vibration gyro according to claim 9, wherein the cut of the frequency adjusting unit is performed by cutting. 11. The method according to claim 9 or 10, wherein at least two frequency adjusting units form a set, and the frequency adjusting units form a set and are symmetrically bonded and fixed to the supporting unit. How to adjust the vibration gyro described.