JP3819333B2 - Columnar vibrator for piezoelectric vibration gyro and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a columnar oscillator for a compact, low-cost piezoelectric oscillating gyroscope, and its manufacturing method facilitating electrode formation and polarization. <P>SOLUTION: In the method of manufacturing the columnar oscillator for the piezoelectric oscillating gyroscope, triangular grooves, trapezoidal grooves, or the like are formed at equal spaces on the surface of a piezoelectric plate, and electrodes are formed on the whole surface and back face of the piezoelectric plate including the groove parts. The high electric field is applied between the electrodes on the back face and surface to polarize the piezoelectric plate in the thickness direction. The surface of the piezoelectric plate is polished to eliminate the surface electrode other than the groove part, and the piezoelectric plate is cut in the thickness direction of the piezoelectric plate and along the triangular grooves or trapezoidal grooves. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a columnar vibrator for a piezoelectric vibration gyro, and is particularly suitable for a gyroscope used in an automobile navigation system, attitude control, camera shake prevention device for a camera-integrated VTR, and the like.
[0002]
[Prior art]
A piezoelectric vibration gyro is an angular velocity sensor that utilizes a dynamic phenomenon in which when an angular velocity is applied to an object having velocity, a Coriolis force is generated in the object itself in a direction perpendicular to the velocity direction.
[0003]
Mechanical vibration (drive vibration) can be excited by applying an electrical signal, and the magnitude of mechanical vibration (detection vibration) in the direction orthogonal to the drive vibration can be detected electrically. When the angular velocity about the axis parallel to the line where the drive vibration surface and the detection vibration surface intersect is given with the drive vibration excited in advance, the detection vibration is caused by the action of the Coriolis force described above. 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.
[0004]
Various types of vibrators have been proposed for vibratory gyro vibrators, but columnar sound piece vibrators made of piezoelectric materials are often used for small and inexpensive vibratory gyros due to their simple shape. .
[0005]
FIG. 4 is a perspective view showing an example of a conventional columnar vibrator described in Japanese Patent No. 2660940, in which a plurality of electrodes 22 are applied to the side surface of a cylinder 21 made of a piezoelectric body, and a high electric field is applied between predetermined electrodes. The columnar shape for a piezoelectric vibration gyro is combined with an electrode that can be polarized in order to excite the drive vibration of the cylinder 21 and an electrode that can electrically detect the magnitude of the detected vibration in the direction orthogonal to the drive vibration. It functions as a vibrator. Because of its simple structure, it was very suitable for small and inexpensive piezoelectric vibration gyros.
[0006]
[Problems to be solved by the invention]
However, although the electrode formation in the conventional columnar vibrator shown in FIG. 4 can be formed with good productivity by printing using a screen mask, the market needs for further downsizing and cost reduction of the piezoelectric vibration gyro are increased, A proposal of a structure of a columnar vibrator that can further improve productivity in electrode formation is also desired. In addition, when simultaneously manufacturing a plurality of columnar vibrators, the conventional polarization processing step requires probing each of the plurality of electrodes on the side surface of the columnar vibrator and applying an electric field, which complicates the process and saves time. There was a problem that it took.
[0007]
An object of the present invention is to solve the above-described problems and to provide a small and inexpensive columnar vibrator for a piezoelectric vibration gyro that can easily perform electrode formation and polarization treatment.
[0008]
[Means for Solving the Problems]
According to the present invention, in a columnar vibrator for a piezoelectric vibration gyro that is provided with a plurality of electrodes on a side surface of a columnar body made of a piezoelectric body, a shape obtained by chamfering two adjacent vertices out of quadrangular vertices. A columnar body having a cross-section of the above-mentioned two chamfered side surfaces, including two side surfaces obtained by chamfering, and a structure in which electrodes are formed on the entire surface of every other three side surfaces that are not adjacent to each other, A columnar vibrator for a piezoelectric vibration gyro having a polarization direction in a direction connecting to a side surface that is not chamfered is obtained.
[0009]
Further, according to the present invention, the piezoelectric body including the groove portion is formed on the surface of the piezoelectric plate by forming a groove corresponding to the side surface obtained by chamfering the side surface such as a triangular groove or a trapezoidal groove at equal intervals. Electrodes are formed on the entire front and back surfaces of the flat plate, and then the piezoelectric flat plate is polarized in the thickness direction by applying a high electric field between the back and front electrodes, and then the surface of the piezoelectric flat plate is polished. And removing the surface electrode other than the groove, and further cutting the piezoelectric flat plate in the thickness direction of the piezoelectric flat plate and along the groove. Is obtained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
FIG. 1 is a perspective view showing an embodiment of a columnar vibrator for a piezoelectric vibration gyro according to the present invention. The columnar body 1 is composed of a columnar body 1 having a hexagonal cross section in which two adjacent vertices are chamfered out of quadrangular vertices, and two of the side surfaces of the columnar body 1 obtained by chamfering are obtained. The detection electrodes 3 and 4 are provided on the entire side surface, and the drive electrode 2 is provided on the entire side surface that is not chamfered.
[0012]
FIG. 2 shows a cross-sectional view of the vicinity of the abdomen of the bending vibration of the columnar vibrator shown in FIG. The polarization treatment is performed from the two detection electrodes 3 and 4 toward the drive electrode 2 as indicated by the direction of the arrow 5 in the figure. As a result, a biased polarization distribution is provided around the corners that are not chamfered. Therefore, by applying an AC voltage between the drive electrode 2 and the detection electrodes 3 and 4 of the columnar vibrator, a displacement distribution biased around the non-chamfered corner is generated, and the drive vibration is excited in the X direction. At the same time, the detection vibration in the Y direction can be detected by measuring the difference between the charges generated in the detection electrodes 3 and 4, and functions as a columnar vibrator for a piezoelectric vibration gyro. The chamfered surfaces need only have the same shape, and a substantially flat surface is suitable, but a curved surface or the like may also be used.
[0013]
Next, a specific manufacturing method in the embodiment of the present invention will be described below with reference to FIG.
[0014]
First, FIG. 3A shows the piezoelectric flat plate 11. Next, as shown in FIG. 3B, a triangular groove or a trapezoidal groove is formed on the surface of the piezoelectric flat plate 11 at equal intervals by a dicing saw, and the front and back surfaces of the piezoelectric flat plate 11 are formed by electroless plating. The electrode 12 is formed on the whole. Here, it is necessary to process the tip of the blade used for dicing into a triangular or trapezoidal shape with symmetrical front and back. Further, after the electrodes are formed, the outer periphery of the piezoelectric flat plate 11 is cut and removed in order to remove unnecessary electrodes attached to the side surfaces of the piezoelectric flat plate 11.
[0015]
Next, as shown in FIG. 3C, a polarization process is performed in the direction of polarization 5 by applying a high voltage between the electrodes on the back surface and the front surface. Incidentally, the degree of polarization becomes stronger in the portion where the distance between the front surface and the back surface is short.
[0016]
Next, as shown in FIG. 3D, the surface of the piezoelectric plate 11 is polished to a predetermined dimension where the surface of the piezoelectric plate 11 appears sufficiently. Finally, as shown in FIG. 3E, the piezoelectric flat plate 11 is cut with a dicing saw in the thickness direction of the piezoelectric flat plate and along a triangular groove or a trapezoidal groove. Thus, the columnar vibrator shown in FIG. 1 is obtained.
[0017]
As described above, the columnar vibrator of the present invention has a very simple structure, and has been devised at the electrode formation position, so that it can be manufactured and a simple method can be taken.
[0018]
【The invention's effect】
According to the columnar vibrator for piezoelectric vibration gyroscope of the present invention, a plurality of electrodes can be formed without using a special pattern mask, and a plurality of columnar vibrators can be simultaneously polarized without requiring a large number of probing. It is possible to obtain a small and inexpensive columnar vibrator for a piezoelectric vibration gyro and a manufacturing method thereof.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a columnar vibrator for a piezoelectric vibration gyro according to the present invention.
2 is a cross-sectional view of the vicinity of an abdomen of bending vibration of the columnar vibrator shown in FIG.
FIG. 3 is an explanatory diagram of specific manufacturing in the embodiment of the present invention. 3A is a cross-sectional view of a piezoelectric flat plate, FIG. 3B is a cross-sectional view in which electrodes are formed on the front and back surfaces after groove processing, and FIG. 3C is a cross-sectional view showing a polarization state after polarization processing. FIG. 3D is a cross-sectional view after polishing the surface of the piezoelectric plate, and FIG. 3E is a cross-sectional view after cutting along the groove in the thickness direction of the piezoelectric flat plate.
FIG. 4 is a perspective view showing an example of a conventional columnar vibrator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,21 Columnar body 2 Drive electrode 3, 4 Detection electrode 5 Arrow 11 which shows the direction of polarization 11 Piezoelectric flat plate 12 Electrode 13 Surface 21 of piezoelectric flat plate Cylinder 22 Electrode

Claims (2)

In the piezoelectric vibrating gyro columnar vibrator comprising subjecting a plurality of electrodes on the side surfaces of the columnar body made of a piezoelectric material, of the vertices of the square, a columnar body having a cross section having a shape chamfered two adjacent vertices, chamfered and includes two side surfaces obtained by the, by the structure of forming the electrode to every other total three whole side surface not adjacent to each other, and a side which has not been been sides and chamfered said two chamfers A columnar vibrator for a piezoelectric vibration gyro, which has a polarization direction in a direction to be connected . A method of manufacturing a piezoelectric vibrating gyroscope for columnar vibrator according to claim 1, to form a groove side at equal intervals on the surface of the piezoelectric flat plate corresponds to the side surface obtained by the above chamfering, including groove portions Electrodes are formed on the entire front and back surfaces of the piezoelectric plate, and then the piezoelectric plate is polarized in the thickness direction by applying a high electric field between the back and front electrodes. A columnar vibrator for a piezoelectric vibration gyro, wherein the surface electrode other than the groove is removed by polishing the surface, and the piezoelectric flat plate is cut along the thickness direction of the piezoelectric flat plate and along the groove. Manufacturing method.

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