JP2590553Y2 - Piezoelectric vibration gyro - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibratory gyroscope using ultrasonic vibration of a piezoelectric vibrator among gyroscopes used for a camera navigation system or a camera-integrated VTR. The present invention relates to a small-sized piezoelectric vibrating gyroscope that has a simple structure and is easily supported, using a mode of energy trapping vibration as a vibration mode of a piezoelectric vibrator.

[0002]

2. Description of the Related Art A piezoelectric vibrating gyroscope is a gyroscope utilizing a dynamic phenomenon that when a rotational angular velocity is applied to a vibrating object, a Coriolis force is generated in a direction perpendicular to the vibration direction.

Generally, when a vibrator is rotated in a state where one vibration is excited in a combined vibration system in which vibrations in two different directions orthogonal to each other can be excited, the above-mentioned action of the Coriolis force causes the vibration. A force acts in a direction perpendicular to the vibration, and the other vibration is excited.

Here, since the magnitude of the vibration is proportional to the magnitude of the vibration of the input-side vibrator and the rotational angular velocity, the magnitude of the vibration of the input-side vibrator is fixed. The magnitude of the rotational angular velocity can be obtained from the magnitude of the output voltage.

As shown in FIG. 7, a conventional piezoelectric vibrating gyroscope has electrodes formed on substantially both sides of a metal triangular prism 110 having a cross section of an equilateral triangle, and electrodes formed on both sides thereof to be polarized in the thickness direction. The three piezoelectric ceramic thin plates 111, 112, 113 thus formed are joined together.

Here, as shown in FIG. 8, the metal triangular prism 110 can bend and vibrate at substantially the same resonance frequency in a direction connecting each side and a vertex facing this side. Sheets of piezoelectric ceramics 111
When a voltage having a frequency substantially equal to the resonance frequency of the metal triangular prism 110 is applied, the surface of the metal triangular prism 110 to which the piezoelectric ceramic thin plate 111 is joined vibrates in a direction perpendicular to the surface.

As shown in FIG. 9, the metal triangular prism 110 is provided on two adjacent piezoelectric ceramic thin plates 111 and 112 with the same amplitude and the same phase as the resonance frequency of the metal triangular prism 110. Is applied, the piezoelectric ceramic thin plate 1
11 and the bending vibration of the metal triangular prism 110 in the direction perpendicular to the surface to which the piezoelectric ceramic thin plate 112 is bonded are combined with each other to form the metal triangular prism 110. The surface to which the other piezoelectric ceramic thin plate 113 is bonded vibrates in a direction perpendicular to this surface.

Further, as shown in FIG. 10, the metal triangular prism 110 is provided on two adjacent piezoelectric ceramic thin plates 111 and 112 with the same amplitude and opposite phase having substantially the same resonance frequency as the metal triangular prism 110. Is applied, the piezoelectric ceramic thin plate 1
11 and the bending vibration of the metal triangular prism 110 in the direction perpendicular to the surface to which the piezoelectric ceramic thin plate 112 is bonded are combined with each other to form the metal triangular prism 110. The surface to which the other piezoelectric ceramic thin plate 113 is bonded vibrates in a direction parallel to this surface.

On the other hand, in the state shown in FIG.
When the metal triangular prism 110 is rotated around the center in the length direction of the metal 10 as a rotation axis, the metal triangular prism 110 is, as shown in FIG. The surface to which the ceramic thin plate 113 is bonded vibrates in a direction perpendicular to this surface and in a direction perpendicular to the surface.

Here, as shown in FIG. 10, the bending vibration of the metal triangular prism 110 in the direction parallel to the surface to which the piezoelectric ceramic thin plate 113 is joined is two adjacent vibrations.
The piezoelectric ceramic thin plates 111 and 112 can be obtained by applying a voltage having the same amplitude and an opposite phase frequency substantially equal to the resonance frequency of the metal triangular prism 110 to the piezoelectric ceramic thin plates 111 and 112.
In a direction parallel to the surface of the metal triangular prism 110 to which the piezoelectric ceramic thin plate 113 is bonded, the metal triangular prism 11
In the case where 0 is caused to bend and vibrate, voltages having the same amplitude and opposite phases are generated in the other two piezoelectric ceramic thin plates 111 and 112 by the reverse action, and the piezoelectric ceramic thin plates 111 and 112 are driven for driving. Is decreased by that amount, and the other voltage is increased by that amount.

Therefore, these piezoelectric ceramic thin plates 1
The voltage of the difference between the terminal voltages of the terminals 11 and 112 is a voltage proportional to the rotational angular velocity of the metal triangular prism 110.

[0012]

In the conventional piezoelectric vibrating gyroscope shown in FIGS. 7 to 11, since the bending vibration mode of the columnar piece is used, the vibrator is supported and fixed. Must be performed at the node of the vibration.

Further, in the conventional piezoelectric vibrating gyroscope,
It was necessary to connect the drive / detection circuit and the electrode of the vibrator with a lead wire, and it was difficult to suppress a change in characteristics due to a variation in the connection state of the lead wire.

Further, the conventional piezoelectric vibrating gyroscope is driven
Since the vibrator supported by the holding member is mounted on the board on which the detection circuit is configured and assembled,
It has been difficult to form a thin piezoelectric vibrating gyroscope.

The present invention has been made in view of the above points, and has as its object to connect a drive / detection circuit and an electrode of a vibrator without using a lead wire. And a thin piezoelectric vibrating gyroscope.

[0016]

According to the present invention, a part of a piezoelectric plate is provided with opposing electrodes facing each other and at least one electrode present in a direction orthogonal to a direction in which the opposing electrodes are connected. An energy trapping vibrator that is polarized in the thickness direction of the piezoelectric plate and utilizes an energy trapping vibration mode, and a drive circuit and a detection circuit provided in another portion on the piezoelectric plate, and applies a voltage between the opposed electrodes. And exciting the piezoelectric plate in a direction connecting the opposing electrodes, and detecting vibration in a direction orthogonal to the exciting direction by an electrode present in a direction orthogonal to the direction connecting the opposing electrodes. A vibrating gyroscope is obtained. Further, according to the present invention, a part of the piezoelectric plate includes a first opposing electrode opposing each other and a second opposing electrode present in a direction orthogonal to a direction in which the first opposing electrode is connected. An energy trapping vibrator that is polarized in the thickness direction of the piezoelectric plate and uses an energy trapping vibration mode, and a drive circuit and a detection circuit provided in another portion on the piezoelectric plate, between the first counter electrode. A piezoelectric vibrating gyroscope, wherein a voltage is applied to excite the piezoelectric plate in a direction connecting the first opposing electrodes, and vibration in a direction orthogonal to the excitation direction is detected by the second opposing electrodes. Is obtained.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

However, the configuration, operation, and the like of a range that can be clearly recalled from the description of the present embodiment are omitted or simplified in order to avoid a complicated description.

Prior to the description of the embodiment, an energy trapping vibrator used in the piezoelectric vibrating gyroscope according to the present invention will be described.

Here, the energy confinement vibration is a vibration mode in which the energy of the vibration is concentrated near the drive electrode, and includes longitudinal vibration in the thickness direction of the piezoelectric plate, sliding vibration, and widthwise vibration of the piezoelectric rectangular plate. There are many vibration modes such as longitudinal vibration and sliding vibration, and they are generally widely used for intermediate frequency filters of FM radios and televisions.

As described above, since the energy of the energy confinement vibration is concentrated near the driving electrode as described above, for example, as shown in FIG. 12 and FIG.
Using a voltage plate 10 of mx 6 mm and a thickness of 0.2 mm, a drive electrode 11
10.7 for FM radio formed with a, 11b and 12
In a MHz ceramic filter, the drive electrode 11
If spaces are formed on both sides of a region having a diameter of 3 mm around a, 11b, and 12, as shown in FIG.
Even if the other parts are fixed by the resin 13, the characteristics of the vibrator are hardly affected.

Accordingly, by forming a space on both sides of a predetermined area around the driving electrodes 11a, 11b and 12 of the piezoelectric plate 10 as described above, the driving electrodes 11
It is possible to obtain a piezoelectric vibrator or a filter using the piezoelectric vibrator in which the formation of the lead terminals a, 11b and 12 is free and the supporting structure does not affect the vibrator characteristics.

1 and 2 show an example of a parallel electric field excitation type thickness-slip mode energy trapping oscillator used in the piezoelectric vibrating gyroscope of the present invention.

In this energy trapping vibrator, opposing partial electrodes 14a and 14b are formed on the same surface of a piezoelectric plate 100 formed such that the polarization direction is the thickness direction.

The partial electrodes 14a, 14 of the piezoelectric plate 100
An electric field in a direction substantially parallel to the surface of the piezoelectric plate 100 is applied to the portion sandwiched by b.

Accordingly, these partial electrodes 14a, 14a are adapted to the characteristics of the piezoelectric material of the piezoelectric plate 100 to be used.
By appropriately designing the b-dimension, the parallel electric field excitation type is applied to the portion of the piezoelectric plate 100 sandwiched between the partial electrodes 14a and 14b by the interaction with the polarization in the thickness direction orthogonal to the direction of the electric field. A thickness-slip mode energy confinement oscillator can be configured.

Here, the thickness-shear vibration is a vibration in which both the displacement and the wave propagation direction are parallel to the surface of the piezoelectric plate, and the displacement distribution in the thickness direction of the piezoelectric plate when resonating at a half wavelength is obtained. ,
As shown in FIG.

FIG. 4 shows another example of the energy-trapping combined oscillator used in the piezoelectric vibrating gyroscope of the present invention.

The combined vibrator has partial electrodes 15 opposed to each other at a predetermined interval on one surface substantially at the center of a piezoelectric plate 110 formed so that the polarization direction is the thickness direction.
a, 15b and 16a, 16b are formed.

Here, the partial electrodes 16a and 16b are formed so as to be orthogonal to the other partial electrodes 15a and 15b.

According to this configuration, like the vibrator shown in FIG. 1, the displacement direction, that is, the vibration direction is the direction in which the partial electrodes 15a and 15b are opposed by the partial electrodes 15a and 15b. The thickness-slip mode energy trapping vibrator is formed, and similarly to the first vibrator, the partial electrodes 16a and 16b cause the vibrating direction to be the direction in which the partial electrodes 16a and 16b face each other. Thus, an energy-trapping-type combined oscillator having the thickness-slip-mode energy-trapping oscillator of No. 2 is obtained.

By the way, the resonance frequency of the above-mentioned thickness slip mode is determined by the thickness of the piezoelectric plate.

Therefore, in the vibrator shown in FIG.
Since the thickness-slip mode energy trapping oscillator and the second thickness-slip mode energy trapping oscillator are both formed on the same piezoelectric plate 110, the resonance frequency of the first thickness-slip mode energy trapping oscillator When,
The resonance frequencies of the second thickness-slip mode energy trapping vibrators become equal to each other.

In FIG. 4, one of the partial electrodes 15a, 15
5b, when an AC voltage having a frequency substantially equal to the resonance frequency of the thickness slip mode is applied, the partial electrodes 15a, 15
Thickness slip vibration is excited only in the vicinity of b.

As shown in FIG. 5, the direction of the displacement at this time is the x-axis direction which coincides with the direction in which the exciting partial electrodes 15a and 15b are opposed to each other.

In this state, the partial electrodes 16a, 1
During 6b, almost no output voltage is generated.

Here, when this combined vibrator is rotated about the z-axis direction perpendicular to the surface of the piezoelectric plate 110 as a rotation axis, Coriolis force is generated in a direction perpendicular to the vibration direction, as shown in FIG. , Vibration in the y-axis direction perpendicular to the vibrating vibration direction is generated.

Since the direction of vibration by the Coriolis force is the same as the direction of vibration by the partial electrodes 16a and 16b, a voltage proportional to the rotational angular velocity of the piezoelectric plate 110 is generated between the partial electrodes 16a and 16b.

FIG. 6 shows an embodiment of the piezoelectric vibrating gyroscope according to the present invention in which the above-described energy trap type decoupling vibrator is formed.

In this embodiment, as shown in FIG. 4, partial electrodes 15a, 15a facing each other at a predetermined interval are provided on a part of the piezoelectric plate 120 formed so that the polarization direction is the thickness direction. The energy trapping type resonating vibrator 17 is formed by forming 15b and 16a, 16b so as to be orthogonal to each other.

Further, in this embodiment, the combined oscillator 1
The drive / detection circuit 20 for the piezoelectric vibrating gyroscope is formed on the same surface of the piezoelectric plate 120 on which the piezoelectric vibrating gyroscope 7 is formed.

The partial electrodes 15a, 15b and 16a, 16 forming the combined vibrator 17 of the piezoelectric vibrating gyroscope
b and the drive / detection circuit 20 are connected to the film conductors 18, 1 formed of a thin film or a thick film formed on the piezoelectric plate 120.
9 is performed.

As a result, the piezoelectric vibrating gyroscope according to the present embodiment includes surface drive components such as an IC, a chip resistor, and a chip capacitor constituting the drive / detection circuit 20, and the partial electrodes 15a, 15b and 1
6a and 16b are directly connected to each other.

In the piezoelectric vibrating gyroscope shown in FIG. 6, since the combined vibrator 17 is constituted by the vibrator in the energy trapping vibration mode as shown in FIG. Even if a support member and other components (the drive / detection circuit 20 in this embodiment) are attached to the portion excluding the vibrating portion, the vibrator characteristics (gyro characteristics)
Has little effect on

In this embodiment, the film conductors 18 and 19 made of a thin film or a thick film formed on the piezoelectric plate 120 are used.
Thus, the partial electrodes 15a, 15 forming the combined vibrator 17
Since the b and 16a, 16b are connected to the drive / detection circuit 20, the gyro characteristics are not adversely affected unlike the conventional connection method of soldering lead wires.

Further, in this embodiment, the drive / detection circuit 20 for the piezoelectric vibrating gyroscope is formed on the same surface of the piezoelectric plate 120 on which the combined vibrator 17 is formed. As compared with the case where the drive / detection circuit is formed on a dedicated substrate independent of the above, a small and thin piezoelectric vibrating gyroscope having a simple structure can be obtained.

[0047]

According to the present invention, as described above, the input / output terminals can be connected without using lead wires, and the piezoelectric vibrating gyro is firmly supported without affecting its gyro characteristics.・ Since it can be fixed, a small and thin piezoelectric vibrating gyroscope with a simple structure and excellent vibration and shock resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a parallel electric field excitation type thickness-slip mode energy trapping vibrator used in the piezoelectric vibrating gyroscope of the present invention.

FIG. 2 is a schematic sectional view of the energy trapping oscillator shown in FIG.

FIG. 3 is a displacement distribution diagram of the energy trapping oscillator shown in FIG. 1;

FIG. 4 is a schematic perspective view of another parallel electric field excited thickness slip mode energy trapping vibrator used in the piezoelectric vibrating gyroscope of the present invention.

FIG. 5 is a displacement distribution diagram of the energy trapping oscillator shown in FIG. 4;

FIG. 6 is a schematic perspective view of one embodiment of a piezoelectric vibrating gyroscope according to the present invention.

FIG. 7 is a schematic perspective view of a conventional piezoelectric vibrating gyroscope.

FIG. 8 is an explanatory diagram of the operation principle of a conventional piezoelectric vibrating gyroscope.

FIG. 9 is another explanatory view of the operation principle of the conventional piezoelectric vibrating gyroscope.

FIG. 10 is still another explanatory view of the operation principle of the conventional piezoelectric vibrating gyroscope.

FIG. 11 is still another explanatory view of the operation principle of the conventional piezoelectric vibrating gyroscope.

FIG. 12 is a schematic plan view of a conventional energy trapping vibrator.

FIG. 13 is a schematic cross-sectional view of the energy trapping oscillator shown in FIG.

FIG. 14 is a schematic sectional view of a support structure of the energy trapping oscillator shown in FIG.

[Explanation of symbols]

 15a, 15b, 16a, 16b Partial electrode 17 Recombination oscillator 18, 19 Film conductor 20 Drive / detection circuit 120 Piezoelectric plate

Claims (2)

(57) [Scope of request for utility model registration] 1. A part of a piezoelectric plate includes opposing electrodes facing each other and at least one electrode present in a direction orthogonal to a direction in which the opposing electrodes are connected to each other. An energy trapping vibrator using a mode, a driving circuit and a detection circuit provided in another portion on the piezoelectric plate, and a voltage is applied between the counter electrodes to connect the counter electrodes in a direction connecting the counter electrodes. A piezoelectric vibrating gyroscope wherein a piezoelectric plate is excited, and vibrations in a direction orthogonal to the exciting direction are detected by electrodes existing in a direction orthogonal to a direction connecting the opposed electrodes. 2. A first piezoelectric element, comprising:
Energy confining vibration formed by utilizing an energy confining vibration mode, polarized in the thickness direction of the piezoelectric plate, and provided with a second counter electrode existing in a direction orthogonal to the direction in which the first and second counter electrodes are connected to each other. And a drive circuit and a detection circuit provided in another portion on the piezoelectric plate, and a voltage is applied between the first counter electrodes, and the piezoelectric plate is moved in a direction connecting the first counter electrodes. A piezoelectric vibratory gyroscope, wherein the piezoelectric vibratory gyroscope is excited and a vibration in a direction orthogonal to the exciting direction is detected by the second counter electrode.