JP3039625B2 - Angular velocity detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity detecting device for detecting an angular velocity of a moving object by detecting Coriolis force. The present device can be applied to a navigation system or attitude control of a moving object such as a vehicle, an aircraft, or a ship, or a camera shake correction of an imaging device.

[0002]

2. Description of the Related Art Coriolis force Fc is proportional to the product (Ω × V) of the angular velocity Ω of the object to be detected and the vibration velocity V of the vibrating body.
It is known that it works on the vibrating body. If the vibration velocity V is constant, the Coriolis force Fc increases in proportion to the angular velocity Ω, so that the vibration state of the vibrating body changes according to the Coriolis force Fc. Therefore, if this vibration state is detected, the angular velocity Ω can be detected. An angular velocity detecting device called a so-called piezoelectric vibrating gyroscope uses a piezoelectric element that converts mechanical vibration into an electrical signal as a vibrating body, and the vibration state of the vibrating body based on the angular velocity Ω of the detected body Is output from this angular velocity detecting device as an electric signal.

[0003] Such a conventional angular velocity detecting device is disclosed in, for example, the 150th Committee of the 150th Committee of the Technology of Elastic Wave Devices of the Japan Society for the Promotion of Science
Materials of the 6th meeting (Hei 8-1-23) p. 198-201
It is described in. This conventional angular velocity detecting device includes a tuning-type piezoelectric vibrator formed by connecting the base ends of two vibrating pieces extending along a predetermined plane. Due to the non-uniformity of the vibrating piece, even when the vibrating piece vibrates in the X-axis direction with the angular velocity being zero, a vibration component in the Z-axis direction orthogonal to the vibrating piece, a so-called leak vibration component, is generated. Have. Since the leak vibration component occurs in the same vibration direction as the vibration due to the Coriolis force, the angular velocity detected based on the Coriolis force is
An error occurs due to the leakage vibration component. One vibrating reed of the above-described conventional vibrator includes a driving electrode for causing the vibrating reeds to vibrate in a coupled manner, and a surface (hereinafter, referred to as a side surface) perpendicular to the predetermined plane of the driving electrode. Are trimmed to reduce their non-uniformity, and thus the leakage vibration component of the resonator element is suppressed.

[0004]

However, in the angular velocity detecting device having the plurality of vibrating pieces, when trimming the driving electrode provided on the side face of the vibrating piece,
Since the reference plane for specifying the direction of the vibrating bar is set on the side surface of one vibrating bar whose extension direction is defined by a single vector, the direction of the vibrating bar is not sufficiently specified, and trimming is not performed. Accuracy cannot be improved. The accuracy of the trimming affects the degree of suppression of the leakage vibration component of the vibrating reed, that is, the detection accuracy of the angular velocity. Therefore, in the above-described conventional apparatus, the detection accuracy of the angular velocity is insufficient. The present invention has been made in view of such a problem, and an object of the present invention is to provide an angular velocity detection device capable of improving the angular velocity detection accuracy as compared with the related art.

[0005]

In order to solve the above-mentioned problems, an angular velocity detecting device according to the present invention comprises first and second vibrating portions capable of coupled vibration when a predetermined signal is applied, When rotation about a predetermined axis is applied to the first and second vibrating portions, the rotation of the first and second vibrating portions is determined by the Coriolis force acting in a predetermined direction perpendicular to both the vibration direction of the first and second vibrating portions and the predetermined axis. The first and second vibrating portions extend along a predetermined plane, the first vibrating portion includes an element to which the predetermined signal is applied, and the element includes the element described above. A surface region substantially parallel to a predetermined plane is provided, and a portion of the surface region is trimmed such that when the angular velocity is zero, the vibration components of the first and second vibration portions in the predetermined direction are reduced. It is characterized by the following.

The first and second vibrating portions vibrate in a coupled manner when a predetermined signal is applied to the element. When the detected object provided with the present angular velocity detecting device makes a motion including a rotational motion component around a predetermined axis, the first and second vibrating portions are subjected to a rotational force around this axis, and the vibration direction and A Coriolis force Fc based on the vibration velocity V and the angular velocity Ω of the object to be detected acts in a predetermined direction perpendicular to both of the predetermined axes. Since the Coriolis force Fc corresponds to the angular velocity Ω of the detected object, the present apparatus can detect the angular velocity Ω of the detected object.

The first and second vibrating portions extend along a predetermined plane, and a surface area of an element for vibrating the vibrating portion is substantially parallel to the plane.
Therefore, when a plane parallel to this plane of the angular velocity detecting device is arranged on a predetermined stage, the surface area of the element becomes substantially parallel to the stage, so that, for example, even when the element is irradiated with a laser beam to perform trimming. The laser beam can be irradiated to this from an accurate angle, and a part of this element can be precisely trimmed. Here, a part of the surface area of the element is trimmed so that the vibration components of the first and second vibration portions in the predetermined direction when the angular velocity is zero are reduced. This predetermined direction coincides with the direction of the Coriolis force Fc. The vibration component in the predetermined direction when the angular velocity is zero is accurately reduced by the trimming. Therefore, by performing this trimming, the vibration component in the predetermined direction, which is superimposed on the vibration component due to the Coriolis force Fc, can be reduced with high accuracy.

The above element is a first electrode, and the first vibrating portion is formed on the first electrode, the crystal provided with the first electrode, and the crystal surface opposed to the crystal surface provided with the first electrode. A second electrode provided, and a third electrode provided on a crystal surface between the first electrode and the second electrode, wherein the first electrode is arranged closer to the third electrode than the second electrode. It is desirable that the trimmed electrode be trimmed. When the distance between the electrodes arranged on the crystal is short, the electric field formed by these electrodes becomes larger than the ideal value, and the crystal bends greatly according to the inverse piezoelectric effect. In the case where the electrode serving as the first electrode is arranged closer to the third electrode than the second electrode in advance, it has been found that the electric field formed by this electrode and the second electrode is larger than an ideal value. If the first electrode is formed by trimming this electrode, the electric field becomes smaller and approaches the ideal value. That is, by setting each electrode in this way, the electrode to be trimmed can be specified.

The above element is a first electrode, and the first vibrating portion includes a first electrode, a crystal provided with the first electrode,
A second electrode provided on a crystal surface opposite to the crystal surface on which the first electrode is provided, wherein the first electrode is formed by trimming an electrode having a larger area than the second electrode. desirable. Since the area of the first electrode is larger than the area of the second electrode, the first electrode has a region that does not overlap with the second electrode in the normal direction. When trimming is performed by irradiating such a region with a laser beam from its normal direction, the second electrode is not trimmed even if the laser beam passes through the crystal.

Further, the element is a first electrode, the first vibrating portion includes a first electrode and a crystal provided with the first electrode, and the second vibrating portion includes another electrode and another crystal. It is preferable that the first electrode be formed by trimming an electrode having a larger area than another electrode. In this case, only by trimming the first electrode of the first vibrating portion, it is possible to reduce the leakage vibration of the first and second vibrating portions that are coupled and vibrate.

[0011] Further, there are provided first and second vibrating reeds capable of coupled vibration and including first and second vibrating parts, respectively.
It is desirable that at least one of the first and second vibrating bars includes an electrically insulated thin film. In this case, the resonance frequency of the resonator element can be adjusted using this thin film.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An angular velocity detecting device according to an embodiment will be described below. The same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 shows an angular velocity detecting device 100 according to the present embodiment. The angular velocity detecting device 100 includes a fixed substrate 1
0, a vibrator 20 fixed to one surface (hereinafter, upper surface) of the fixed substrate 10 and a driving signal fixed to the other surface (hereinafter, lower surface) of the fixed substrate 10 to vibrate the vibrator 20 An electric circuit 30 for detecting a signal output from the vibrator 20 in accordance with the vibration state of the vibrator 20
It has.

The upper surface of the fixed substrate 10 has a main surface 11 and an installation surface 12 adjacent to the main surface 11. Main surface 11
The boundary between the mounting surface 12 and the mounting surface 12 forms a step S, and the mounting surface 1
The reference numeral 2 is more distant from the lower surface of the fixed substrate 10 than the main surface 11. As shown in the drawing, the crystal has an X axis, a Y axis, and a Z axis that are orthogonal to each other, and the main surface 11 and the installation surface 12 of the fixed substrate 10 are both parallel to the XY plane.

The vibrator 20 includes a main surface 11 of the fixed substrate 10.
And a predetermined distance from each other. This vibrator 20
Is configured by providing a plurality of electrodes on a crystal. Vibrator 20
The upper and lower surfaces of the quartz crystal are substantially perpendicular to the Z axis of the quartz crystal,
Therefore, these upper and lower surfaces are parallel to the XY plane orthogonal to the Z axis of the crystal. The vibrator 20 includes the fixed substrate 11
The fixing portion 1 is fixed to the installation surface 12 of the fixing device. Also,
The vibrator 20 is separated from the fixed part 1, the support part 2 extending along the Y axis of the crystal, the base 3 extending from the tip of the support part 2 along both the positive and negative directions of the X axis of the crystal, and away from the fixed part 1. And a pair of excitation vibrating reeds 4 and 5 extending from both ends of the base 3 and a pair of detecting vibrating reeds 6 and 7 extending from both ends of the base 3 so as to approach the fixed portion 1. Each vibrating bar 4, 5, 6, 7
Are metal thin films 4e and 5 for adjusting the resonance frequency.
e, 6e, and 7e are provided at the distal end, respectively. These thin films 4e, 5e, 6e, 7e are not connected to any wiring and are therefore electrically insulated. Also, a plurality of electrode pads 1 a
To 1 h, and each electrode 4 a to 4 b of the resonator element 4 to 7.
4d, 5a to 5d, 6a to 6d, and 7a to 7d (see FIG. 2) are electrically connected to the electric circuit 30 via wiring (not shown) and electrode pads 1a to 1h.

FIG. 2 shows the angular velocity detector 10 shown in FIG.
0 is a system configuration diagram of FIG. 5, which shows a cross section taken along the line AA of the excitation vibrating reeds 4 and 5 shown in a region XA, and a region XB.
2 shows a cross section taken along the line BB of the detecting vibrating reeds 6 and 7 shown therein, and an electric circuit 30 electrically connected to the vibrator 20.

The excitation vibrating reeds 4 and 5 have crystal pieces 4p and 5p having a substantially rectangular cross section perpendicular to the Y axis of the crystal. The crystal blanks 4p and 5p are mounted on a quartz substrate (Z
Plate) is etched from its upper and lower surfaces. In the description, a substantially rectangular shape means not only a rectangular shape defined mathematically, but also crystal pieces 4p and 5p as shown in FIG.
Pentagonal cross-sectional shape based on the imperfectness of the etching when etching. Electrodes 4a to 4d and 5a to 5d are provided on each side of the crystal blanks 4p and 5p having a substantially rectangular cross-sectional shape, respectively.

The detecting vibrating reeds 6, 7 have crystal pieces 6p, 7p having a substantially rectangular cross section perpendicular to the Y axis of the crystal. Electrodes 6a to 6d and 7a to 7d are placed on the corners of crystal blanks 6p and 7p each having a substantially rectangular cross-sectional shape.
Is provided.

The electric circuit 30 generates a predetermined AC voltage signal to generate the electrodes 4a and 4b and the electrodes 4c and 4 of the vibrating piece 4 for excitation.
d, electrodes 5a to 5 of the excitation vibrating reed 5 which vibrate in conjunction with the vibration of the excitation vibrating reed 4
It comprises an impedance conversion circuit 32 for converting a current signal input from d into a voltage signal, a buffer circuit 33 such as a voltage follower, a DC cut capacitor 34 for cutting a DC component of the signal, a demodulation circuit 35, and an amplification circuit 36. An excitation drive circuit is provided, and the excitation vibrating reeds 4, 5 are continuously coupled and vibrated along the X-axis direction of the crystal by the signal output from the excitation drive circuit.

The electric circuit 30 includes the detecting vibrating reed 6,
7, the electrodes 6a to 6d, 7
a to 7d, an impedance conversion circuit 37 that converts a current signal input to a voltage signal into a voltage signal, a differential amplifier circuit 38 that outputs a difference between two signals input in opposite phases, and a differential amplifier circuit 3
8, a phase shift circuit 39 for shifting the phase of the signal output from the self-exciting circuit 31 by about 90 ° so as to match the phase of the signal output from the self-exciting circuit 31, a signal synchronized with the phase of the signal output from the self-exciting circuit 31 A synchronous detection circuit 40 performs synchronous detection of a signal output from the phase shift circuit 39 and performs full-wave rectification, an integration circuit 41 for smoothing a signal output from the synchronous detection circuit 40, and an amplification circuit 42. A detection circuit. Therefore, the amplifier circuit 42 outputs a DC voltage signal proportional to the vibration amplitude of the detecting vibrating bars 6 and 7 in the Z-axis direction.

When a voltage signal from the excitation drive circuit is input to the excitation vibration piece 4, the excitation vibration piece 4 bends along the X-axis direction according to the inverse piezoelectric effect of the crystal piece 4p. The parameters of each circuit of the oscillation circuit including the excitation drive circuit and the excitation vibrating bars 4 and 5 are set so as to satisfy the oscillation conditions. Further, the excitation vibrating piece 5 is mechanically coupled to the excitation vibrating piece 4 via the base 3 of FIG. 1, and when the excitation vibrating piece 4 vibrates in the X-axis direction, the reverse is applied. Vibrates in phase. Therefore, the excitation vibrating bars 4 and 5
Vibrates continuously along the X-axis.

When the vibrating vibrating bars 4 and 5 are vibrating in the X-axis direction, the object provided with the angular velocity detecting device moves at the angular velocity Ω around the rotation axis Y1 shown in FIG. Is performed, the Coriolis force Fc proportional to the product (V × Ω) of the vibration velocity V and the angular velocity Ω of the excitation vibrating reeds 4 and 5 in the X-axis direction is obtained.
Acts on the vibrating reeds 4 and 5 along the Z-axis direction. The excitation vibrating reeds 4, 5 also vibrate in the Z-axis direction by the Coriolis force Fc. This vibration is also transmitted to the detecting vibrating reeds 6, 7, so that the detecting vibrating reeds 6, 7 vibrate along the Z-axis direction. Therefore, the vibration amplitude of the detecting vibrating bars 6 and 7 in the Z-axis direction is proportional to the angular velocity Ω of the detected object. When the detecting vibrating pieces 6 and 7 vibrate in the Z-axis direction, the quartz pieces 6p and 7p are set based on the piezoelectric effect of the quartz pieces 6p and 7p.
From each of the electrodes 6a to 6d and 7a to 7d provided on 7p,
An AC signal SA whose amplitude is proportional to the amplitude of the vibration is output. The AC signal SA is input to a detection circuit, and the detection circuit outputs a DC voltage signal SD proportional to the amplitude of the AC signal SA.
Is output. DC voltage signal S output from the detection circuit
The level of D is proportional to the amplitude of the AC signal SA,
The amplitude of A is proportional to the amplitude of the vibration of the detecting vibrating reeds 6, 7, and the amplitude of the vibration of the detecting vibrating reeds 6, 7 is proportional to the angular velocity Ω of the detected object. Therefore, the level of the DC voltage signal SD output from the detection circuit is proportional to the angular velocity Ω of the detected object.

FIG. 3 shows a cross section perpendicular to the Y-axis of the crystal of the excitation vibrating reed 4. Quartz blank 4p divided into four by Z axis and X axis passing through center of gravity O in XZ plane of crystal blank 4p
Are defined as regions R1, R2, R3 and R4, respectively. Part 40a of the surface area of the electrode 4a on the upper surface of the resonator element 4
Is trimmed by moving the laser beam LB in the direction of the arrow X1 while scanning the laser beam LB in the Y-axis direction. At a certain moment, the electrodes 4a and 4b and the electrode 4
When a predetermined voltage is applied between c and 4d, the regions R1 and R4 extend along the Y-axis direction and the regions R2 and R3 contract along the Y-axis direction according to the inverse piezoelectric effect. The resonator element 4 is bent along the positive X-axis direction of the quartz crystal. The extension amount of the region R1 depends on the electrodes 4a and 4d
It is approximately proportional to the magnitude of the electric field between them. Similarly, the extension amount of the region R4 depends on the magnitude of the electric field between the electrodes 4b and 4d and the region R2.
Is the amount of electric field between the electrodes 4a and 4c, the amount of contraction of the region R3 is the amount of electric field between the electrodes 4b and 4c,
It is almost proportional.

The crystal blank 4p is an ideal rectangle, and the extension amounts of the regions R1 and R4 are equal, and the regions R2 and R
When the contraction amounts of the pieces 3 are equal, the resonator element 4 bends along the X axis. However, the cross-sectional shape of the actual crystal blank 4p is not an ideal rectangle, and each of the regions R1 to R4
Of the vibrating piece 4 does not coincide with the X axis before the trimming is performed because the amount of expansion and contraction of the vibrating piece 4 also varies due to imperfect cross-sectional shapes and manufacturing errors in the mounting positions of the electrodes 4a to 4d. . Here, it is assumed that the extension amount of the region R4 before the trimming is performed is larger than the extension amount of the region R1. In this case, the resonator element 4 bends according to the stress in the direction from the region R4 to the region R2. That is, the vibration of the resonator element 4 due to the bending has not only a vibration component in the X-axis direction but also a vibration component in the Z-axis direction (hereinafter, leakage vibration component). Since the leak vibration component in the Z-axis direction is transmitted to the detecting vibrating piece 6 shown in FIG. 1 and is output as angular velocity information, the leak vibration component in the Z-axis direction causes a measurement error. In particular, even when the angular velocity of the object to be detected is zero, when there is a leakage vibration component,
The measured angular velocity will show a non-zero value. Therefore, a portion 40a of the electrode 4a provided on the region R2
Is removed by trimming, the magnitude of the electric field formed by the electrodes 4a and 4c becomes smaller, so that the contraction amount of the region R2 defined by the electric field becomes smaller.
When the amount of contraction of the region R2 is small, it resists the stress applied from the region R4 to the region R2, so that the vibration component of the resonator element 4 in the Z-axis direction can be removed.

Actually, the extension amount of the region R4 is equal to that of the region R1.
It is not known whether it is larger than the amount of extension of, and it is unknown which part should be trimmed. Therefore,
The electrode 4a before trimming is made closer to the electrode 4c than the electrode 4b in advance. In this case, the contraction amount of the region R2 is significantly larger than the ideal value, and as a result, the stress from the region R4 toward the region R2 is reduced by the crystal blank 4p.
Occurs within. That is, the extension amount of the region R4 is equal to the region R1.
Is larger than the amount of elongation, the stress component in the positive Z-axis direction due to the contraction of the region R2 is added to the stress component in the positive Z-axis direction due to the expansion of the region R4, and the vibration component in the positive Z-axis direction is further increased. However, when it is small, the stress component in the negative direction of the Z-axis due to the extension of the region R1 is reduced by
It is canceled by the stress component in the positive axis direction. Since the contraction amount of the region R2 is set to be very large, the leakage vibration component in the Z-axis direction has a positive value at a certain moment due to the electrode 4a before being trimmed in any case. Have. With this setting, the region R
Only by trimming a portion 40a of the electrode 4a on the second 2, the magnitude of the leak vibration component in the positive Z-axis direction at a certain moment can be made close to zero. That is, according to the above-described electrode arrangement, it is possible to specify a trimming portion for reducing a leakage vibration component.

In order to make the leak vibration component in the Z-axis direction as close to zero as possible and to improve the detection accuracy of the present angular velocity detecting device, it is necessary to improve the accuracy of the trimming. Therefore, trimming by the laser beam LB is performed as follows. Referring again to FIG. 1, the excitation vibrating reeds 4, 5
The surface regions of the upper surface electrodes 4a and 5a are substantially parallel to a virtual plane (XY plane) defined by the extension direction of the resonator elements 4 and 5. The lower surface of the fixed substrate 10 set in a plane parallel to the XY plane is arranged on an XY stage of a laser beam trimming device (not shown), and the laser beam is irradiated from above vertically onto the electrode 4a before being trimmed. The trimming is performed by moving the stage in the XY plane. In this trimming, the angular velocity detector is fixed to a stationary XY stage (angular velocity Ω =
0), while measuring the amplitude of the AC voltage signal output from the output point A in FIG. 2, so that the measured amplitude approaches zero. In other words, a portion 40a of the electrode 4a has an angular velocity Ω
Is zero so that leakage vibration components in the Z-axis direction of the excitation vibrating reeds 4 and 5 are trimmed.

Each of the vibrating bars 4 to 7 in FIG. 1 is provided with an electrically insulated metal thin film 4 e to 7 e for adjusting the resonance frequency, and these thin films 4 e to 7 e correspond to those in FIG. While measuring the frequency of the AC output voltage of the self-exciting circuit 31,
Trimming is performed so that the measured frequency becomes a target set value. That is, the frequency difference (fx−fx) between the resonance frequency fx of the excitation vibrating reeds 4 and 5 in the X-axis direction and the resonance frequency fz of the detection vibrating reeds 6 and 7 in the Z-axis direction is 2 × the resonance frequency fx. Trimming is performed so as to be 2.5%. When the lower surface of the fixed substrate 10 is arranged on the XY stage, the surface areas of the electrodes 4a and 5a become substantially parallel to the stage. Therefore, since the electrodes 4a and 5a can be irradiated with the laser beam from an accurate angle with respect to this plane, a part of the electrodes 4a and 5a can be trimmed precisely, and the accuracy of the detected angular velocity is improved. be able to. Further, when a camera is arranged above the XY stage, by processing an image captured by the camera, the position can be detected by automatic control, and productivity can be improved.

For the trimming, a sand blast that emits metal particles, sand, or an abrasive from a nozzle can be used in addition to the laser trimmer using the laser beam. Further, the trimming of the excitation vibrating reed 5 can be performed using the same method as that of the vibrating reed 4.
However, since the vibrating bar 5 is coupled with the vibrating bar 4, the vibrating bar 5 vibrates.
The trimming of the vibrating reed 5 does not necessarily have to be performed, and the vibrating reed 5 does not need to be arranged in an electrode like the vibrating reed 4 as described below.

FIG. 4 shows a cross section perpendicular to the Y-axis of the crystal of the vibrating piece 5 for excitation. The vibrating piece 5 for excitation is different from the vibrating piece 4 in that the electrode 5a before trimming is used in advance.
Is not closer to the electrode 5c than the electrode 5b,
The electrode 5a is not trimmed. In this case, the excitation vibrating piece 5 alone has a leakage vibration component in the Z-axis direction. Here, it is assumed that, at a certain moment, the resonator element 5 has a component in the negative direction of the Z axis. In this case, the vibrating reed 4 before trimming shown in FIG. 3 independently has a component in the positive direction of the Z-axis. And have a larger leakage vibration component in the Z-axis direction.

By slightly trimming only the electrode 4a of one of the vibrating reeds 4, the leakage vibration component of the vibrating reed 4 alone can be removed. At this time, since the vibrating reed 5 still has a leak vibration component in the Z-axis direction, the vibrating reed 4 having a coupled vibration has a leak vibration component in the Z-axis direction. Therefore, by itself, the electrode 4a of the resonator element 4 is further trimmed until it has a leak vibration component in the Z-axis direction in a direction opposite to that before the trimming. In this case, the leakage vibration components of the vibrating reeds 4 and 5 that undergo coupled vibration cancel each other. Therefore, only by trimming the electrode 4a of the vibrating reed 4, it is possible to reduce the leakage vibration component of the vibrating reeds 4 and 5 that vibrate in a coupled manner. By performing the trimming in this way, the step of trimming the resonator element 5 can be omitted, and the area of the electrode 4a to be trimmed can be set large. When the area of the trimmed electrode 4a is large, the following advantages are obtained.

In FIG. 3, the area of the upper electrode 4a before trimming is equal to the area of the lower electrode 4b. At this time, an electrode region overlapping in the Z-axis direction exists in the cross section shown in FIG. In this case, a portion of the electrode 4b immediately below the portion 40a to be removed by trimming may be removed by transmitting the laser beam LB through the crystal blank 4p. As described above, when the area of the electrode 4a to be trimmed can be made larger than that of the opposing electrode 4b, the laser beam LB is
Even when p is transmitted, the opposing electrode 4b can be prevented from being removed. The wavelength of the laser beam transmitted through the crystal blank 4p is 1.064 μm (YA
G laser). In order not to transmit the crystal piece 4p, it is desirable to use a laser beam having a wavelength longer than at least 1.064 μm. In addition, the wavelength 10.6
When a laser beam of μm (CO2 laser) is used, the laser beam is absorbed by the crystal blank 4p and
p is damaged. Therefore, in order not to damage the crystal blank 4p, it is desirable to use a laser beam having a wavelength shorter than at least 10.6 μm.

FIG. 5 shows a cross section of the excitation vibrating reed 4 in which the area of the electrode 4a to be trimmed is larger than that of the opposing electrode 4b as described above. Since the area of the upper electrode 4a before the trimming of the vibrating reed 4 is larger than the area of the lower electrode 4b, the normal of the upper electrode 4a before the trimming necessarily passes through the lower electrode 4b. Not have areas. In this case, even in the case where the laser beam LB passes through the crystal blank 4p in this region, the lower surface electrode 4b is not removed, and high-precision trimming can be performed. Note that the portion to be trimmed is not limited to the above, and the portion described below may be trimmed.

FIG. 6 shows a cross section of the excitation vibrating reed 4. In this resonator element 4, the extension amount of the region R1 is different from that of the other regions R.
It is assumed that it is larger than the expansion and contraction amount of 2 to R4. In this case, by removing a portion 40a of the electrode 4a on the region R1 by trimming, the electric field by the electrodes 4a and 4d can be reduced, the amount of extension can be reduced, and the Z-axis leakage vibration of the resonator element 4 can be reduced. Components can be reduced. Also,
Even when the contraction amount of the region R3 is larger than the contraction amounts of the other regions R1, R2, and R4, a portion of the electrode 4a on the region R1
Oa is removed by trimming to obtain the region R
By reducing the amount of expansion of the vibration element 1, the contraction of the region R3 can be limited, and the vibration component in the Z-axis direction of the resonator element 4 can be reduced.

As described above, the angular velocity detecting device 100 according to the present embodiment includes the first and second vibrating portions 4 and 5 capable of coupled vibration by applying a predetermined signal. A predetermined axis (Y1
Coriolis that acts in a predetermined direction (Z-axis) perpendicular to both the vibration direction (X-axis) and a predetermined axis (Y1-axis) of the first and second vibrating portions 4 and 5 when rotation about the axis is applied. Force Fc
Therefore, in the angular velocity detecting device that detects the angular velocity Ω of rotation, the first and second vibrating parts 4 and 5 extend along a predetermined plane (XY plane), and the first vibrating part 4 receives the predetermined signal. An element (electrode) 4a to be applied is provided.
a has a surface area substantially parallel to a predetermined plane (XY plane), and a part 40a of this surface area has the above-mentioned predetermined direction (1) of the first and second vibrating parts 4, 5 when the angular velocity Ω is zero. Z
The shaft is trimmed to reduce the vibration component. As described above, according to the present embodiment, since the leakage vibration component in the Z-axis direction can be precisely reduced, the detection accuracy of the angular velocity detecting device can be improved.

In the above embodiment, the amplitude of the vibration is described as the vibration state. However, this may be a state indicating a physical quantity such as the phase or mode of the vibration.

In the above embodiment, an electrode is used as the element 4a. However, if the vibrating parts 4 and 5 are coupled and vibrate by application of a signal, the element 4a is constituted by a piezoelectric element instead of the electrode 4a. Transducers may be used. In this case, the first vibrating portion 4 may be configured by attaching the transducer to a metal column.

In the embodiment described with reference to FIG. 3, the element 4a is a first electrode and the first vibrating portion 4
Are a first electrode 4a and a quartz crystal 4 provided with the first electrode 4a.
p, the second electrode 4b provided on the surface of the crystal 4p opposite to the surface of the crystal 4p provided with the first electrode 4a, and the surface of the crystal 4p between the first electrode 4a and the second electrode 4b. Provided with a third electrode 4c provided, and the first electrode 4a is provided with a second electrode 4b.
An electrode arranged closer to the third electrode 4c is trimmed. As described above, the electrode 4a
By setting the positions of 〜4c, the trimming portion of the electrode 4a can be specified. By this trimming, the first and second vibrating parts 4, when the angular velocity is zero,
The magnitude of the vibration component in the direction orthogonal to the vibration direction of No. 5 can be made close to zero.

In the embodiment described with reference to FIG. 5, the element 4a is a first electrode and the first vibrating portion 4
Are a first electrode 4a and a quartz crystal 4 provided with the first electrode 4a.
p, and a second electrode 4b provided on the surface of the crystal 4p opposed to the surface of the crystal 4p provided with the first electrode 4a, wherein the first electrode 4a has an area larger than that of the second electrode 4b. Is trimmed. Since the area of the first electrode 4a is larger than the area of the second electrode 4b, the first electrode 4a has a region that does not overlap with the second electrode 4b in the normal direction.
When such a region is irradiated with a laser beam LB from its normal direction and trimmed, the laser beam LB
Is not transmitted through the crystal 4p, the second electrode 4b is not trimmed.

In the embodiment described with reference to FIGS. 3 and 4, the element 4a is a first electrode, and the first vibrating portion 4 is provided with the first electrode 4a and the first electrode 4a. The second vibrating portion 5 includes another electrode 5a.
And a crystal 5p provided with another electrode 5a.
The electrode 4a is formed by trimming an electrode having a larger area than another electrode 5a. In this case, only by trimming the first electrode 4a of the first vibrating part 4, it is possible to reduce the leakage vibration of the first and second vibrating parts 4 and 5, which are coupled and vibrate. By performing the trimming in this way, the trimming step of the second vibrating portion 5 can be omitted, and the trimmed area of the first electrode 4a can be set large.

Further, in the embodiment described with reference to FIG. 1, the first and second vibrating reeds 4, 5 which are capable of coupled vibration and include the first and second vibrating portions 4, 5 respectively are provided. At least one of the first and second vibrating reeds 4, 5 includes thin films 4e, 5e that are electrically insulated. This thin film 4
e and 5e can be trimmed so that the resonance frequencies of the resonator elements 4 and 5 become the target set values.

[0041]

As described above, according to the angular velocity detecting device of the present invention, it is possible to precisely trim a part of the element for vibrating the vibrating part, thereby improving the angular velocity detection accuracy. Can be.

[Brief description of the drawings]

FIG. 1 is a perspective view of an angular velocity detecting device according to an embodiment.

FIG. 2 is a system configuration diagram of the angular velocity detection device shown in FIG.

FIG. 3 is a sectional view of an excitation vibrating reed.

FIG. 4 is a sectional view of an excitation vibrating reed.

FIG. 5 is a sectional view of an excitation vibrating piece.

FIG. 6 is a sectional view of an excitation vibrating reed.

[Explanation of symbols]

100: angular velocity detecting device, 4, 5: vibration part, 4a: element, 40a: part.

Continuation of the front page (56) References JP-A-9-89568 (JP, A) JP-A-3-276013 (JP, A) JP-A-62-250309 (JP, A) JP-A-10-96632 (JP, A) JP-A-5-71966 (JP, A) JP-A-6-194117 (JP, A) JP-A-6-258333 (JP, A) JP-A-7-280572 (JP, A) 3-291517 (JP, A) JP-A-64-31015 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 19/56 G01P 9/04

Claims (5)

(57) [Claims] A first vibration section that is coupled to a predetermined signal to be applied to the first vibration section and a second vibration section that is coupled to the first vibration section when a rotation about a predetermined axis is applied to the first vibration section and the second vibration section;
An angular velocity detecting device for detecting the angular velocity of rotation from Coriolis force acting in a predetermined direction perpendicular to both the vibration direction of the first and second vibration parts and the predetermined axis, wherein the first and second vibration parts Extends along a predetermined plane, the first vibrating portion includes an element to which the predetermined signal is applied, the element has a surface area substantially parallel to the predetermined plane, and An angular velocity detecting device, wherein a part is trimmed so that when the angular velocity is zero, the vibration component of the first and second vibration parts in the predetermined direction is reduced. 2. The device according to claim 1, wherein the element is a first electrode, and the first vibrating portion includes the first electrode, a crystal provided with the first electrode, and a surface of the crystal provided with the first electrode. A second electrode provided on the surface of the crystal opposite to the first electrode, and a third electrode provided on the surface of the crystal between the first electrode and the second electrode, wherein the first electrode comprises: The angular velocity detecting device according to claim 1, wherein the trimming is performed on an electrode arranged closer to the third electrode than the second electrode. 3. The device according to claim 1, wherein the element is a first electrode, and the first vibrating portion includes the first electrode, a crystal provided with the first electrode, and a surface of the crystal provided with the first electrode. And a second electrode provided on a surface of the crystal opposed to the first electrode, wherein the first electrode is formed by performing the trimming on an electrode having a larger area than the second electrode.
3. The angular velocity detecting device according to claim 1. 4. The device according to claim 1, wherein the element is a first electrode, the first vibrating portion includes the first electrode, and a crystal provided with the first electrode, and the second vibrating portion includes another electrode. And a crystal provided with the another electrode, wherein the first electrode comprises:
The angular velocity detecting device according to claim 1, wherein the trimming is performed on an electrode having a larger area than the another electrode. 5. A method according to claim 1, further comprising: first and second vibrating pieces that are capable of coupled vibration and include the first and second vibrating portions, respectively.
The angular velocity detecting device according to claim 1, wherein at least one of the first and second vibrating bars includes a thin film that is electrically insulated.