JPH10325728A - Adjustment method of angular velocity sensor - Google Patents

Abstract

(57) Abstract: An object of the present invention is to surely suppress unnecessary vibration in a detection axis direction generated when a vibrator is vibrated in a drive axis direction, and to reduce offset temperature drift of an angular velocity sensor. SOLUTION: In an angular velocity sensor provided with a tuning-fork-shaped vibrator 2, a driving signal whose phase is inverted is input to driving electrodes 12a and 12b to vibrate the vibrator 2. The frequency of the drive signal is not the resonance frequency in the drive axis direction that excites the vibrator 2 when detecting the angular velocity, but the resonance frequency in the detection axis direction orthogonal to the drive shaft. Then, the current flowing through the detection electrode 22b is detected by using the current-voltage conversion circuit 44, the detection signal and the drive signal are displayed on the oscilloscope 46, and the ridge line of the transducer 2 to be trimmed is determined from the phase difference between the signals. Then, the ridge is trimmed until the amplitude of the detection signal becomes zero (or a predetermined threshold). As a result,
Unwanted vibration in the detection axis direction generated at the time of angular velocity detection can be suppressed, and offset temperature drift can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adjustment method for adjusting vibration characteristics of a vibrator constituting a vibration type angular velocity sensor used for vehicle control of automobiles, navigation, and prevention of camera shake of a video camera.

[0002]

2. Description of the Related Art Conventionally, an angular velocity sensor provided with a tuning-fork-shaped vibrator comprising, for example, a pair of arm portions formed in a prismatic shape and a connecting portion connecting one end of each of the arm portions (for example, Japanese Patent Application Laid-Open No. H08-208, 1988) JP-A-210860), an angular velocity sensor provided with a prism-shaped vibrator having one end fixed (see JP-A-8-152328), or a node of vibration fixed so that both ends are free. 2. Description of the Related Art An angular velocity sensor that detects an angular velocity by using a vibrating portion formed in a prismatic shape, such as an angular velocity sensor having a prismatic vibrator (for example, see Japanese Patent Application Laid-Open No. 6-241815) is known.

In this type of angular velocity sensor, a vibrating portion of a vibrator is vibrated in a predetermined drive axis direction orthogonal to a central axis in a longitudinal direction of the vibrator, and when an angular velocity is input to the vibrator, the vibrator is activated. This is for detecting the angular velocity applied to the vibrator by detecting the Coriolis force received from the magnitude of vibration generated in the detection axis direction orthogonal to the drive axis direction in the vibrating part. Formed of metal,
Two types are known, one in which a driving and detecting piezoelectric body is attached to the outer wall, and the other in which a vibrator is formed of a piezoelectric body and driving and detecting electrodes are formed on the outer wall.

In this type of angular velocity sensor, the resonance frequency of the vibrating portion in the direction of the drive axis (in other words, the frequency of the drive signal when the vibrator is vibrated in the direction of the drive axis;
Hereinafter, the drive frequency fd) and the resonance frequency in the detection axis direction (in other words, the vibration frequency in the detection axis direction at the time of detecting the angular velocity; hereinafter, referred to as the detection frequency fs) are close to each other. For this reason, when the angular velocity sensor is vibrated in the drive axis direction at the drive frequency fd, the vibration section vibrates in the detection axis direction even though the angular velocity is not applied to the angular velocity sensor, and an unnecessary detection signal (offset) is generated. Signal).

If the offset signal is always constant irrespective of the use environment of the angular velocity sensor, the angular velocity can be accurately detected by removing the offset signal from the detection signal obtained at the time of detecting the angular velocity. However, actually, since the offset signal changes depending on the temperature of the angular velocity sensor, the conventional angular velocity sensor has a problem that the angular velocity cannot be detected with high accuracy by the offset signal.

On the other hand, conventionally, as a method of reducing the offset signal, for example, as disclosed in Japanese Patent Laid-Open No. 6-289043, an angular velocity sensor is actually driven to detect the offset signal, and the offset signal is detected. It has been proposed to adjust the vibration characteristics of the vibrator so that the signal becomes zero.

[0007]

However, in the above-mentioned conventional adjusting method, a change in the offset signal with respect to a change in the temperature of the angular velocity sensor (hereinafter referred to as offset temperature drift).
Was not able to be reduced sufficiently. In other words, conventionally, the vibration characteristics of the vibrator were adjusted based on the idea that the offset temperature drift can be reduced to zero by setting the offset signal generated when the angular velocity is not applied to the angular velocity sensor to zero. Even if the offset signal is set to zero under the conditions, an offset signal is generated when the temperature of the vibrator changes, and the offset temperature drift cannot be set to zero.

[0008] When the inventor of the present application investigated the cause in detail, the following was found. That is, the offset signal is not only an unnecessary vibration generated in the detection axis direction when the vibrator is vibrated in the drive axis direction, but also a drive signal applied to a driving electrode or a piezoelectric body for driving the vibrator. It also changes due to electric noise generated inside the vibrator, harmonic components of the resonance frequency in the drive axis direction and the detection axis direction of the vibrator, and the like. The offset temperature drift is caused by the unnecessary vibration of the vibrator, which is affected by the temperature, out of the unnecessary vibration of the vibrator, electrical noise, harmonic components of the resonance frequency, and the like that affect the offset signal. , Found to be unaffected by other factors.

Therefore, even if the offset signal is simply detected and the vibration characteristics of the vibrator are adjusted so that the offset signal becomes zero, unnecessary vibration of the vibrator that affects the offset temperature drift is reduced. Not always possible,
As a result, the conventional adjustment method cannot surely reduce the offset temperature drift.

The present invention has been made in view of such a problem, and in a vibration type angular velocity sensor, unnecessary vibration in a detection axis direction generated when a vibrator is vibrated in a drive axis direction is suppressed, and a detection signal is generated. An object of the present invention is to provide a method for adjusting an angular velocity sensor that can reliably suppress offset temperature drift.

[0011]

According to a first aspect of the present invention, there is provided a vibrator having a vibrating portion formed in the shape of a prism and a driving signal input from the outside. An angular velocity sensor comprising: a driving unit that excites the vibrator in a driving axis direction orthogonal to a central axis in a longitudinal direction of the vibrating unit; and a detecting unit that detects vibration generated in the vibrating unit in a detection axis direction orthogonal to the driving shaft. An adjustment method for adjusting the vibration characteristics of the vibrator in order to suppress unnecessary vibration of the vibrating portion generated in the detection axis direction when the vibrator is excited by the driving means, and corresponds to the resonance frequency of the vibrating portion in the detection axis direction. The vibrator is vibrated by inputting the obtained AC voltage as a drive signal to the drive means, and the vibration characteristics of the vibrator are adjusted so that the amplitude of the detection signal obtained by the detection means at that time becomes small. And it features.

As described above, according to the method of the present invention, in adjusting the vibration characteristics of the vibrator, the vibrator is not vibrated at the driving frequency fd at the time of detecting the angular velocity as in the related art.
The vibrator is vibrated at a resonance frequency (detection frequency fs) in the detection axis direction. Therefore, in the present invention, the detection signal obtained at the time of adjusting the vibration characteristics includes, in addition to the unnecessary vibration generated in the detection axis direction when the vibrating portion of the vibrator is vibrated in the drive axis direction, as well as the offset signal generated at the time of normal driving. Therefore, although noise components such as electrical noise and harmonic components of the resonance frequency are included, the noise components are significantly reduced, and the detection signal changes according to unnecessary vibration in the detection axis direction of the vibration unit. .

That is, according to the method of the present invention, since the vibrating portion is vibrated at the detection frequency fs, unnecessary vibration generated in the detection axis direction is reduced as compared with the case where the vibrating portion is vibrated at the drive frequency fd. The detection signal obtained through the detection means can be greatly amplified, and changes substantially corresponding to the unnecessary vibration without being substantially affected by the noise component. The transfer characteristic of the vibration component at the detection frequency fs can be detected.

In the present invention, since the vibration characteristics of the vibrator are adjusted so that the amplitude of the detection signal is reduced, unnecessary vibration which occurs in the detection axis direction of the vibrating portion at the time of detecting the angular velocity is ensured by this adjustment. The offset temperature drift caused by the unnecessary vibration can be suppressed.

When the vibration characteristics of the vibrator are adjusted by the method of the present invention, the detection signal obtained when detecting the angular velocity includes:
Noise components such as electrical noise and harmonic components of the resonance frequency are superimposed as an offset signal, but since this offset signal does not change with temperature, this offset signal is removed from the detection signal. This makes it possible to detect the angular velocity extremely accurately.

Here, the adjustment of the vibration characteristics of the vibrator refers to the adjustment of the rigidity of the vibrator, and more specifically, a member (for example, a metal piece or the like) capable of adjusting the rigidity of the vibrator. May be applied or the cross-sectional shape of the vibrator may be changed by a method of cutting off a part of the vibrator. In particular, when a part of the vibrator is cut off as described in claim 2, the adjusting operation can be performed easily as compared with a case where the adjusting member is attached to the vibrator.

When adjusting the characteristics of the vibrator by shaving a part of the vibrator, the wall surface of the vibrator may be shaved. In this way, at least one of the ridges along the longitudinal direction of the vibrating portion may be cut in the vibrator.

When adjusting the vibration characteristics of the vibrator by shaving the ridge line of the vibrating section, the vibrator may include a pair of arm sections as a vibrating section, When each of the arm portions is formed in a tuning fork shape by a connecting portion that connects one end of each arm portion, at least one of the ridges along the longitudinal direction of the pair of arm portions in the vibrator may be cut off. Good. In other words, a tuning fork-shaped vibrator is provided with a pair of arms connected to each other by a connecting portion as a vibrating portion for detecting an angular velocity. However, a ridgeline on one arm side of the pair of arms is cut off. If
The vibration characteristics of the whole vibrator can be adjusted.

Further, as an angular velocity sensor for detecting an angular velocity using a tuning fork as described above, two sets of tuning forks each including a pair of arms and a connecting part are connected to each tuning fork. By combining and integrating the connecting parts of the parts, a comb-shaped or H-shaped vibrator is provided, and at the time of detecting the angular velocity, the driving means sets each arm constituting one tuning fork of the vibrator to each arm. Excitation is performed in the drive axis direction orthogonal to the central axis in the longitudinal direction of the arm section, and the detection means is configured to detect the detection axis in the detection axis direction orthogonal to the drive axis generated in each of the arms constituting the other tuning fork that is not excited by the drive means. It is also conceivable to configure to detect vibration.

In the angular velocity sensor having such a comb-shaped or H-shaped vibrator, when adjusting the vibration characteristics of the vibrator, the lengthwise direction of the arm portion constituting the two sets of tuning fork portions is adjusted. If at least one of the ridge lines is cut, the vibration characteristics of the entire vibrator can be adjusted.

An angular velocity sensor having a tuning fork-shaped vibrator according to claim 4 or an angular velocity sensor having a comb-shaped or H-shaped vibrator combining two sets of tuning forks as set forth in claim 5 In the above, the vibration characteristic of the vibrator can be greatly changed by shaving the vicinity of the root of the arm portion forming the tuning fork. Therefore, in this case, the adjustment operation of the arm portion is performed as described in claim 6. Any of a ridgeline near the connecting portion, a ridgeline of the connecting portion, and a ridgeline from the vicinity of the connecting portion of the arm portion to the connecting portion side may be cut.

In this way, the vibration characteristics of the vibrator can be largely changed with a relatively small amount of shaving, so that the amount of shaving the vibrator for adjusting the vibration characteristics can be reduced. As a result, the adjustment operation can be performed efficiently, and the strength of the vibrator can be prevented from being reduced by the adjustment.

On the other hand, if the vibrator is not a tuning fork or a comb or an H-shape having two sets of tuning forks, but is composed of one vibrating portion having one end of a prism fixed, the invention will be described in claim 7. In the case where the vibrator consists of one vibrating part in which the part that becomes a node during vibration is fixed so that both ends of the prism are free, As described in claim 8, the ridgeline near the center in the longitudinal direction of the vibrating portion may be cut. This is because when the vibrator consists of one vibrating part with one end of the prism fixed, the vibration characteristics can be greatly changed by shaving the vicinity of the fixed part of the vibrating part. This is because, in the case where a portion serving as a node at the time of vibration so as to be free is composed of one fixed vibrating portion, the vibration characteristic can be largely changed by cutting the vicinity of the central portion in the longitudinal direction of the vibrating portion. . In other words, this way,
The amount of shaving of the vibrator during the adjustment can be reduced, the efficiency of the adjusting operation can be improved, and the strength of the vibrator can be prevented from being reduced by the adjustment.

When adjusting the vibration characteristics of the vibrator by shaving the ridge line of the vibrating portion as described above, any ridge line that can reduce the amplitude of the detection signal may be used as the ridge line for performing the adjustment work, but should be shaved. When the shape (dimensions) of the vibrator is determined, the ridge line can be uniquely set based on the relationship between the phase of the drive signal input to the drive means and the phase of the detection signal. The signal and the detection signal may be simultaneously monitored, and the ridgeline for performing the adjustment operation may be determined based on the phase relationship between the signals.

When the vibration characteristics of the vibrator are adjusted by cutting the ridge line of the vibrating portion, the length of cutting the ridge line may be adjusted.
As described in above, the depth at which the ridge line is cut may be adjusted. And if you cut the ridge like this,
Excessive shaving will increase the amplitude of the detection signal,
In such a case, the amplitude of the detection signal can be reduced by cutting other ridge lines (for example, if the vibrating portion is a quadrangular prism, adjacent ridge lines).

Further, the adjusting method according to the present invention detects a transmission characteristic of a vibration component corresponding to a resonance frequency of the vibrator in a detection axis direction, and adjusts the vibration characteristic of the vibrator so as to reduce the transmission characteristic. Therefore, regardless of the shape of the vibrator as described above (tuning fork shape, comb shape using a tuning fork or H-shape, prismatic shape), an angular velocity using a vibrator having one or more vibrating portions formed in a prismatic shape is used. Any type of angular velocity sensor can be applied as long as it is a so-called vibration type angular velocity sensor that detects the angular velocity.

More specifically, for example, an angular velocity sensor in which a vibrator is formed of metal and a piezoelectric body as a driving unit and a detecting unit is attached to an outer wall thereof, or the vibrator is formed of a piezoelectric body Even if it is an angular velocity sensor in which an electrode as a driving means and a detecting means is formed on its outer wall,
The effects described above can be obtained by applying the method of the present invention.

In particular, when the vibrator is used for adjusting an angular velocity sensor made of a piezoelectric material, an angular velocity sensor capable of detecting the angular velocity with high accuracy can be realized at low cost, which is preferable. . In other words, an angular velocity sensor in which a vibrator is formed of a piezoelectric body does not require a piezoelectric body to be attached to the vibrator, and therefore can be manufactured more easily and at a lower cost than an angular velocity sensor in which a vibrator is formed of metal. If the present invention is applied to adjustment of this type of angular velocity sensor, an angular velocity sensor that can obtain good detection accuracy can be realized at low cost.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view illustrating the entire configuration of the angular velocity sensor according to the embodiment, and FIG. 2 is an explanatory diagram illustrating the vibrator according to the embodiment as viewed from front, rear, left and right.

As shown in FIG. 1, the angular velocity sensor of the present embodiment has a vibrator formed in a tuning fork shape by a pair of left and right arms 4, 6 and a connecting portion 8 connecting one end of each of the arms 4, 6. 2 is provided. The arm portions 4 and 6 and the connecting portion 8 of the vibrator 2 are each in the shape of a quadrangular prism, and the vibrator 2 is manufactured by integrally forming these components with a piezoelectric body.
The piezoelectric body constituting the vibrator 2 can be a ceramic piezoelectric body such as PZT, quartz, or the like. However, the vibrator 2 of this embodiment can be set to any polarization direction and is easy to manufacture. PZT is used.

Next, as shown in FIG. 2A, one surface (X1 surface) of the vibrator 2 having a concave shape is provided with a pair of drive electrodes 12 from the connecting portion 8 to the respective arm portions 4 and 6.
a, 12b are formed, and these drive electrodes 12a, 12b are formed.
b, the monitor electrodes 14a, 14b and the temporary GND electrodes 16a, 16b
And polarization electrodes 18a and 18b are formed in this order, and pad electrodes 20a and 20b for extracting a detection signal are formed at the tips of the arms 4 and 6, respectively.

Then, the drive electrodes 12a and 12b pass through the connecting portion 8 and the opposing surfaces of the arms 4, 6 facing each other, and the left and right outer surfaces (Y1, Y
2) and the monitor electrodes 14a and 14
b is formed on each of the facing surfaces of the arms 4 and 6, respectively, and the provisional GND electrodes 16a and 16b are
The polarization electrodes 18a and 18 are formed on the Y1 and Y2 surfaces, respectively.
b is formed in the entire width direction from the Y1, Y2 surface side of each arm portion 4, 6 to the opposing surface side, and the pad electrodes 20a and 20b are respectively formed on the Y1, Y2 surface side of each arm portion 4, 6 respectively. Is formed. In addition, each of the polarization electrodes 18a and 18b is
The temporary GND electrode 16 is connected via the short-circuit electrodes 26a and 26b.
a, 16b are respectively connected (short-circuited).

On the other hand, as shown in FIGS. 2B and 2C, the detecting electrodes 22a, 18b are located on the Y1 and Y2 sides of the arms 4, 6, respectively, at positions corresponding to the polarizing electrodes 18a, 18b.
On the other surface (X2 surface) of the vibrator 2 having a concave shape, drive electrodes 12a and 12b, monitor electrodes 14a and 14b, and a detection electrode 18a are formed as shown in FIG. , 18b as a reference electrode for
An ND electrode 24 is formed. The detection electrodes 22a,
22b is the Y1, Y2 surface of each arm part 4, 6;
It is formed at the position on the X2 plane side from the center.

Then, the provisional GND electrode 24 on the X2 side and the X
The temporary GND electrodes 16a and 16b on the first surface are the short-circuit electrodes 2 formed on the Y1 and Y2 surfaces of each arm 4.6, respectively.
They are connected (short-circuited) to each other via 8a and 28b. Further, the pad electrodes 20a, 20b on the X1, X2 surface side
And the detection electrodes 22a and 22b on the Y1 and Y2 surfaces are connected (short-circuited) to each other via detection signal extraction electrodes (extraction electrodes) 30a and 30b formed on the Y1 and Y2 surfaces, respectively. .

Note that the vibrator 2 of the present embodiment includes detection electrodes 22a and 22b and short-circuit electrodes 28 formed on the Y1 and Y2 planes.
a, 28b and the extraction electrodes 30a, 30b are formed on each surface of the piezoelectric body formed in a tuning fork shape, and then X
By applying a voltage between the electrodes formed on the X1 and X2 planes, the piezoelectric body is polarized in the direction from the X1 plane to the X2 plane (the direction indicated by the arrow in FIG. 1). The detection electrodes 22a and 22b and the short-circuit electrodes 28a and 28
b and the extraction electrodes 30a and 30b are formed respectively, and the provisional GND electrode 24 on the X2 side and the provisional GND electrode 16 on the X1 side are formed.
a, 16b, pad electrodes 20a, 20b on the X1 side and Y
The detection electrodes 22a and 22b on the Y1, Y2 side are short-circuited, respectively.

Next, in the vibrator 2 thus manufactured, the end face on the connecting portion 8 side is bonded to the pedestal portion 32b of the supporter 32 having a U-shaped cross section with an adhesive (for example, an epoxy-based adhesive). Then, the main body side of the supporter 32 is fixed to the surface of the plate-like base 36 by welding or bonding via a spacer 34, so that the back surface (X2 surface) is Is fixed so as to face the surface.

The supporter 32 has a pedestal 32 for joining the vibrator 2 to a main body fixed to a base 36 via a spacer 34 via a neck 32a for absorbing vibration.
b, and is integrally formed in a D-shaped cross section with a metal such as 42N, for example. Further, the base 36 is for fixing the vibrator 2 directly or via a vibration-proof rubber to a housing of the angular velocity sensor or a vehicle body or the like for which an angular velocity is to be detected. The base 36 has eight terminals T1 to T8 corresponding to the drive electrodes 12a and 12b, the monitor electrodes 14a and 14b, the temporary GND electrodes 16a and 16b, and the pad electrodes 20a and 20b formed on the vibrator 2. It is erected. Each terminal T1-T8
Is for relaying each electrode to a detection circuit (not shown), and each electrode and terminals T1 to T8 are
They are connected by wire bonding via wires W1 to W8, respectively. Note that the base 36 and the terminals T1 to T8 are electrically insulated.

When detecting the angular velocity using the angular velocity sensor of the present embodiment having the above-described configuration, first, the driving electrodes 12a and 12b formed on the X1 plane of the vibrator 2 and the X
By applying an alternating voltage whose phase is inverted as a drive signal between the temporary GND electrodes 24 formed on the two surfaces as drive signals, the arms 4 and 6 are aligned in the direction in which the arms 4 and 6 are arranged (left and right). ) In the direction of the drive axis (Y axis shown in the figure). The frequency of the AC voltage applied as the drive signal at this time is the resonance frequency of the vibrator 2 in the Y-axis direction. During this driving, the monitor electrodes 14a, 14a
The output (current) from b is monitored, and the drive signal is controlled so that the amplitude in the Y-axis direction of each of the arms 4 and 6 becomes constant even when the temperature changes (self-excited control oscillation).

Next, when the vibrator 2 is oscillated by self-excited control as described above, a Z-axis centered on the Z-axis parallel to the arms 4, 6 at the center position of the arms 4, 6. When the angular velocity Ω about the axis is input, each of the arms 4 and 6 is moved in the X-axis direction (the detection axis direction) through the X1 and X2 planes by Coriolis force.
Vibrates. Since the vibration component in the X-axis direction is proportional to the current flowing between the detection electrodes 22a and 22b and the temporary GND electrode 24, the current between each of these electrodes is converted into a voltage value. The angular velocity Ω is detected by taking the difference between the values.

When the angular velocity Ω around the Z-axis is detected using the angular velocity sensor of the present embodiment as described above, the detection accuracy of the angular velocity Ω decreases when the offset temperature drift occurs. Therefore, in the present embodiment, adjustment is performed to suppress unnecessary vibration in the X-axis direction in each of the arms 4 and 6 which is a main cause of the offset temperature drift to zero or a predetermined threshold or less. Hereinafter, this adjustment method will be described.

When performing this adjustment work, the provisional GND electrode 24 is grounded to the reference potential, and each drive electrode 12a, 1
An AC drive signal which fluctuates around the reference potential and whose phase is inverted is applied to 2b. Specifically, as shown in FIG. 3, an AC drive signal is generated from the oscillator 40, and the drive signal is directly input to the drive electrode 12b.
This drive signal is input to the drive electrode 12a via an inversion circuit 42 for phase inversion. At this time, the frequency of the drive signal output from the oscillator 40 is not the drive frequency fd at the time of detecting the angular velocity, but the resonance frequency (detection frequency fs) of each of the arms 4 and 6 in the X-axis direction.

On the other hand, the detection electrode 22b is
A current-voltage conversion circuit 44 for converting a current flowing between the “b” and the temporary GND electrode 24 into a voltage is connected, and a detection signal indicating a vibration state of the arm unit 6 in the X-axis direction is connected through the circuit 44. Take out. Note that the current-voltage conversion circuit 44 is a known circuit including an operational amplifier OP1 and a resistor R1.

Then, the detection signal and the driving signal from the oscillator 40 are input to the oscilloscope 46, respectively.
Display each signal waveform. And the oscilloscope 46
In the case where the level (amplitude) of the detection signal indicated in the above is larger than zero (or a predetermined threshold), the direction in which the vibrator 2 is to be trimmed is determined from the phase relationship between the signals, and the ridge line in that direction is determined. Is trimmed using a router 48 or the like (see FIG. 4A).

For example, as shown in FIG. 5A, when the drive signal and the detection signal have the same phase, the right arm 6
5B is trimmed, and as shown in FIG. 5B, when the drive signal and the detection signal are in opposite phases, as shown in FIG. Trim the ridge portion that is the boundary with the Y1 plane. Then, since the amplitude of the detection signal decreases, the trimming is continued until the amplitude becomes substantially zero (or a predetermined threshold value).

FIG. 6 shows the result of actually adjusting the vibrator 2 (sample 1 and sample 2) in such a procedure. FIG.
As shown in (a), in the case of sample 1, before the adjustment, the phase of the detection signal and the drive signal are in phase, and the detection signal (output)
Is 56.2 mV, while the ridge portion which is the boundary between the X1 plane and the Y2 plane of the right arm 6 is trimmed, the phase is kept in phase, and the amplitude is adjusted to 5.
Reduced to 6 mV. As a result, 17 ° /
The offset temperature drift that occurred for sec. could be reduced to 3 ° / sec. On the other hand, as shown in FIG. 6B, in the case of sample 2, before the adjustment, the phase of the detection signal and the driving signal were opposite, and the amplitude of the detection signal (output) was 37.5 mV. On the other hand, by trimming the ridge portion which is the boundary between the X1 plane and the Y1 plane of the left arm section 4, the amplitude was reduced to 3.2 mV while the phase remained opposite. As a result, the offset temperature drift, which was 11 ° / sec. Before the adjustment, could be reduced to 2 ° / sec. Therefore, it can be seen that the adjustment method described above can reduce unnecessary vibration of the vibrator 2 in the detection axis direction (X-axis direction) and sufficiently suppress the offset temperature drift.

Next, the relationship between the trimming amount, the amplitude of the detection signal, and the offset temperature drift will be described. FIG.
As shown in FIG. 7, when the phase of the drive signal and the phase of the detection signal are opposite to each other, the ridge portion which is the boundary between the X1 plane and the Y1 plane of the left arm unit 4 is trimmed by the above adjustment method. Although the amplitude of the detection signal decreases, if the amount of trimming is further increased, the phase of the drive signal and the detection signal is inverted to become the same, and the amplitude of the detection signal increases. On the other hand, the offset temperature drift decreases as the vibration characteristic of the vibrator 2 changes due to the trimming. However, when the trimming amount is further increased, the gradient with respect to the temperature is inverted, and the drift width increases. . Next, in a state where the phase relationship between the drive signal and the detection signal is inverted and the respective signals are in the same phase, the ridge portion which is the boundary between the X1 plane and the Y2 plane of the right arm 6 is trimmed. Then, the amplitude of the detection signal decreases, and the offset temperature drift also decreases. Therefore, even when trimming is excessively performed at the time of adjusting the vibration characteristics of the vibrator 2 by trimming, the vibration characteristics can be easily readjusted by changing the trimming position (ridge line).

The size of the vibrator 2 of the present embodiment is such that the width of each of the arms 4 and 6 in the Y-axis direction (lateral direction) is about 2.0 m.
m, the gap (width in the Y-axis direction) between the arm portions 4 and 6 is about 0.6 mm, the width of the connecting portion 8 in the Z-axis direction is about 3 mm, and the arm portions 4 and 6 and the connecting portion 8 are in the X-axis direction. Is about 2.1m thick
m, the length from the tip of the arm portion 4, 6 in the Z-axis direction of the connecting portion 8 to the end face of the connecting portion 8 on the supporter 32 side is about 20 mm. The length of the supporter 32 in the Z-axis direction is about 4 mm.
It is.

Then, in the vibrator 2 of this size,
5 from the root of arm 4 or 6 (joining position with connection 8)
Even if trimming was performed on the tip side separated by not less than mm, a great effect was not obtained. The trimming position may be such that only the arm portions 4 and 6 or the connecting portion 8 is trimmed. However, in order to obtain an effect with a small trimming amount in consideration of the damage of the vibrator 2, It is desirable to trim both the parts 4, 6 and the connecting part 8. Further, when trimming in this manner, the shaving depth may be adjusted in the vicinity of the roots of the arms 4 and 6, but the depth should be limited to about 0.5 mm in consideration of the damage of the vibrator 2. Is desirable.

By the way, in the description of the above adjusting method, when the phase of the detection signal and the phase of the drive signal are the same, the ridge portion which is the boundary between the X1 plane and the Y2 plane of the right arm 6 is trimmed, When the phase of the detection signal and the phase of the drive signal are opposite to each other, it has been described that the ridge portion which is the boundary between the X1 plane and the Y1 plane of the left arm unit 4 is trimmed, but the amplitude of the detection signal is reduced. (In other words, to reduce the offset temperature drift), the position of the ridge line to be trimmed differs depending on the shape and size of the vibrator 2. Therefore, if the type of the vibrator is different, the detection signal and the drive signal are different. The ridge line to be trimmed may be reversed depending on the topological relationship. Therefore, for the ridge line to be trimmed first according to the phase relationship between the detection signal and the drive signal,
What is necessary is just to set suitably according to the kind of the vibrator to be adjusted.

In the case of a tuning-fork-shaped vibrator as in this embodiment, as shown in FIG.
The change in the vibration characteristics obtained when the ridge line P1 outside (Y1 side) of one surface is shaved is the ridge line P2 inside the X2 surface of the left arm portion 4 and the ridge line inside the X1 surface of the right arm portion 6. P
3 or the ridge line P outside the X2 plane of the right arm 6
4 can also be realized in the same manner. The change in vibration characteristics obtained when the ridge line P5 outside the X1 plane (Y2 side) of the right arm section 6 is shaved is the ridge line P6 inside the X2 plane of the right arm section 6 and the left arm section. X1 of 4
Ridge line P7 on the inner side of the surface or X2 of the arm 4 on the left side
The same can be realized by cutting the ridge line P8 outside the surface. Therefore, at the time of the above adjustment, from the ridge lines from which the same characteristic change is obtained, a ridge line that is easy to work is appropriately selected,
You may make it trim.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, but can take various forms. For example, in the above embodiment, in order to detect the vibration of the vibrator 2 in the X-axis direction (detection axis direction) at the time of adjustment, the output from the detection electrode 22b formed on the right arm portion 6 is taken in. But
For example, as shown in FIG. 8, the outputs from the detection electrodes 22a and 22b formed on the left and right arms 4 and 6 are respectively sent to a pair of current-voltage conversion circuits 44a and 44b including an operational amplifier OP1 and a resistor R1. Alternatively, these detection signals may be input to the differential amplifier 45 to obtain a difference between the detection signals, and the difference may be input to the oscilloscope 46 as a detection signal.

Further, in the above-described embodiment, at the time of adjustment, it has been described that the vibrator 2 is vibrated at the detection frequency fs using the pair of drive electrodes 12a and 12b provided on the vibrator 2. Represents one drive electrode 12a (or 1
2b) and the provisional GND electrode 24 can be caused to vibrate simply by applying an AC voltage. Therefore, during adjustment, the vibrator 2 is caused to vibrate using only one of the drive electrodes 12a (or 12b). You may. However, in this case, it goes without saying that the frequency of the drive signal is the detection frequency fs.

On the other hand, in the above embodiment, the adjusting method of the angular velocity sensor provided with the tuning-fork-shaped vibrator 2 has been described. However, the adjusting method of the present invention includes the vibrator having the vibrating portion formed in a prismatic shape. As long as the angular velocity sensor is used, it can be applied in the same manner as the above embodiment. That is, as the angular velocity sensor, besides the one having the tuning fork-shaped vibrator, for example,
As shown in FIG. 9A, an electrode is formed on a quadrangular prism-shaped piezoelectric body, and one end thereof is fixed on a base 56 by a supporter 54 made of a metal having a U-shaped cross section (such as 42N). 10A, for example, as shown in FIG.
An electrode is formed on a quadrangular prism-shaped piezoelectric body, and a portion serving as a node of vibration is formed on support bases 74 and 75 made of resin or the like.
An angular velocity sensor including a vibrator including one vibrating portion formed in a prismatic shape, such as a vibrator including a vibrator 72 fixed on the sensor 6 is known.

As an angular velocity sensor for detecting an angular velocity using a tuning fork, as shown in FIGS. 11 and 12,
Two sets of two arm portions constituting a tuning fork are provided, and these arm portions 103, 104, 105, and 106 are arranged in parallel, and one end thereof is connected by a common connecting portion 102, thereby forming a comb shape. 13, or as shown in FIG. 13, two sets of two arms constituting a tuning fork are provided, and these sets of arms 203, 204 and 205, 206 are respectively connected to a connecting part. The oscillator 20 formed in an H shape by being arranged and connected on both sides of the
One using 0 is also conceivable.

Also in these angular velocity sensors, if the vibration characteristics of the vibrator are adjusted in the same manner as in the above embodiment, an angular velocity sensor free from offset temperature drift can be realized. Hereinafter, the configuration and adjustment method of each of these angular velocity sensors will be described.

The vibrator 52 of the angular velocity sensor shown in FIG. 9A has the same configuration as the right arm 6 of the vibrator 2 of the above embodiment, and as shown in FIG. A pair of drive electrodes 58a and 58b, a monitor electrode 60, and a temporary electrode are arranged on the surface (X1 plane) of the piezoelectric body formed in the shape of a quadrangular prism from the fixed end side fixed on the base 56 via the supporter 54 in order. GND electrode 62, polarization electrode 64,
A pad electrode 66 is formed, and on the right side (Y2 side) side,
A detection electrode 68 is provided at a position corresponding to the polarization electrode 64 on the X1 plane.
Are formed, and the driving electrode 5 is formed on the back surface (X2 surface) side.
8A and 58B, a temporary GND electrode 70 serving as a reference electrode for the monitor electrode 60 and the detection electrode 68 is formed. The provisional GND electrode 62 is connected (short-circuited) to the polarization electrode 64 via the short-circuit electrode 62a formed on the X1 plane, and is connected to the X2 plane via the short-circuit electrode 62b formed on the Y2 plane. The pad electrode 66 is connected (short-circuited) to the temporary GND electrode 70, and is connected to the detection electrode 68 on the Y2 surface via an extraction electrode 66a formed on the Y2 surface.

The detection electrode 68 is formed at a position on the X2 plane side from the center of the Y2 plane. No electrode is formed on the left side surface (Y1 plane) of the vibrator 52. The vibrator 52 of this embodiment is manufactured in the same procedure as that of the vibrator 2 of the above embodiment, and the piezoelectric body constituting the vibrator 52 is polarized in the direction from the X1 plane to the X2 plane.

Next, the vibrator 52 is fixed on the base 56 via the supporter 54 such that the X2 plane of the vibrator 52 faces the surface of the base 56, similarly to the vibrator 2 of the above embodiment. However, on the base 56, five terminals T11 to T15 corresponding to the drive electrodes 58a and 58b, the monitor electrode 60, the provisional GND electrode 62, and the pad electrode 66 formed on the X1 plane of the vibrator 52 are erected. Each of these electrodes and terminals T11 to T15 are connected to a wire W
Connection is made by wire bonding via 11 to W15 (see FIG. 9A). The base 56 and the terminals T11 to T15 are electrically insulated.

When the angular velocity is detected by using the angular velocity sensor of the present embodiment thus configured, the driving electrode 58
a, 58b and the provisional GND electrode 70, respectively, by applying an alternating voltage of which phase is inverted as a drive signal, the vibrator 52 is driven in the left and right drive axis directions around the supporter 54 (Y axis shown in the figure). Direction), and further controls the drive signal so that the output from the monitor electrode 60 (in other words, vibration in the Y-axis direction) becomes constant (self-excited control oscillation).
Needless to say, the frequency (drive frequency fd) of the AC voltage applied as a drive signal at this time is
2 is the resonance frequency in the Y-axis direction. When the vibrator 52 is oscillated by self-excited control, the vibrator 5
When the angular velocity Ω centered on the central axis (Z axis) in the longitudinal direction of No. 2 is input, the vibrator 52 generates X
Vibrates also in the X-axis direction (detection axis direction) that penetrates the X1 and X2 planes,
Since the vibration component in the X-axis direction is proportional to the current flowing between the detection electrode 68 and the temporary GND electrode 70, by converting the current between these electrodes into a voltage value, the angular velocity Ω around the Z-axis is obtained. Is detected.

On the other hand, when adjusting the vibrator 52 of this embodiment, for example, the oscillator 40, the inverting circuit 42,
The drive electrodes 58a and 58b are connected to the temporary G by using an adjustment system including the current-voltage conversion circuit 44 and the oscilloscope 46.
By applying a drive signal having a resonance frequency (detection frequency fs) in the X-axis direction of the vibrator 52 in the X-axis direction and a phase inverted from each other to the ND electrode 70, the vibrator 52 is driven at the detection frequency fs. Vibration is performed, and a detection signal and a drive signal obtained from the detection electrode 68 at that time are monitored. When the level (amplitude) of the detection signal is larger than zero (or a predetermined threshold), the ridge of the vibrator 52 determined by the phase relationship between the detection signal and the drive signal is trimmed to obtain the detection signal. The amplitude of zero (or a predetermined threshold)
To lower. As a result, unnecessary vibration of the vibrator 52 in the X-axis direction is eliminated, and the offset temperature drift of the angular velocity sensor can be reduced as in the above-described embodiment. When adjusting the vibration characteristics of the vibrator 52 as described above, the ridge portion near the supporter 54 in the vibrator 52 may be trimmed.

On the other hand, the vibrator 72 of the angular velocity sensor shown in FIG. 10A uses the electrodes of the vibrator 52 shown in FIG.
This is formed symmetrically in the vertical direction from the center in the longitudinal direction of the piezoelectric body with respect to the quadrangular prism-shaped piezoelectric body.
As shown in FIG. 5, a pair of left and right drive electrodes 82a and 82b are formed at the center in the longitudinal direction of the surface (X1 plane) of the piezoelectric body. Then, on the X1 plane above and below the drive electrodes 82a and 82b, monitor electrodes 84a and 84b are provided, respectively.
b and the temporary GND electrodes 86a and 86b are formed.
Above and below, a polarization electrode 88a, 88b and a pad electrode 90a, 90b are formed in order.

On the right side (Y2 plane) of the vibrator 72, detection electrodes 92a and 92b are formed at positions corresponding to the polarization electrodes 88a and 88b on the X1 plane, respectively.
Surface), drive electrodes 82a and 82b, monitor electrode 84
a, 84b, and a temporary GND electrode 94 serving as a reference electrode for the detection electrodes 92a, 92b. The temporary GND electrodes 96a and 96b are respectively connected to the polarizing electrodes 88 via the short-circuit electrodes 96a and 96b formed on the X1 plane.
a, 88b (short-circuit), and via the short-circuit electrodes 98a, 98b formed on the Y2 surface, to the temporary GND electrode 94 on the X2 surface (short-circuit). Further, the pad electrodes 90a, 90b , Detection electrodes 92a, 92 on the Y2 surface via extraction electrodes 99a, 99b formed on the Y2 surface, respectively.
2b.

The detection electrodes 92a and 92b are formed on the Y2 plane at a position closer to the X2 plane than the center. No electrode is formed on the left side surface (Y1 plane) of the vibrator 72. And the vibrator 72 of the present embodiment is
The piezoelectric body, which is manufactured by substantially the same procedure as the vibrators 2 and 72 of the above embodiment, is polarized in a direction from the X1 plane to the X2 plane.

Next, the vibrator 72 of this embodiment drives the both ends of the vibrator 72 left and right by applying an alternating voltage whose phase is inverted between the drive electrodes 82 a and 82 b and the temporary GND electrode 94. Since the vibrator can be vibrated in the axial direction (Y-axis direction), two portions serving as nodes of the vibration are supported by supporters 74 and 75 made of resin.
5, and is fixed on the base 76. The drive electrodes 82a, 82 formed on the X1 plane of the vibrator 72
b, monitor electrodes 84a, 84b, temporary GND electrodes 86a,
86b and the pad electrodes 90a and 90b are respectively connected to eight terminals T21 to T28 erected on the base 76.
Are connected by wire bonding via wires W21 to W28 (see FIG. 10A). The base 76 and the terminals T21 to T28 are electrically insulated.

When detecting the angular velocity using the angular velocity sensor of the present embodiment having the above-described configuration, the driving electrode 82
a, 82b and the provisional GND electrode 94, by applying an alternating voltage of which phase is inverted as a drive signal to resonate both ends of the vibrator 72 in the Y-axis direction, and furthermore, monitor electrodes 84a, 84b (In other words, vibration in the Y-axis direction) is controlled so that the drive signal is constant (self-excited control oscillation). The frequency of the drive signal at this time is also the resonance frequency of the vibrator 72 in the Y-axis direction, as in the above embodiment. When the vibrator 72 is self-excited and oscillated in this way, when an angular velocity Ω about the longitudinal central axis (Z axis) of the vibrator 72 is input, both ends of the vibrator 72 are Are, by Coriolis force, X
Vibrates also in the X-axis direction (detection axis direction) that penetrates the X1 and X2 planes,
Since the vibration component in the X-axis direction is proportional to the current flowing between the detection electrodes 92a and 92b and the provisional GND electrode 94, the current between these electrodes is converted into a voltage value.
The angular velocity Ω around the Z-axis is detected by calculating the difference between the respective voltage values using a differential amplifier circuit or the like.

On the other hand, when adjusting the vibrator 72 of this embodiment, for example, the adjustment system shown in FIG. 3 or FIG. 8 is used to apply vibration between the drive electrodes 82a and 82b and the provisional GND electrode 94. By applying a drive signal having a resonance frequency (detection frequency fs) in the X-axis direction of the vibrator 72 and a phase inverted from each other, the vibrator 72 is vibrated at the detection frequency fs. A detection signal obtained from the 92b side (or a detection signal obtained by calculating a difference between the detection signals obtained from the respective electrodes 92a and 92b) and a drive signal are monitored. When the level (amplitude) of the detection signal is greater than zero (or a predetermined threshold), the detection is performed by trimming the ridge line of the vibrator 72 determined by the phase relationship between the detection signal and the drive signal. The amplitude of the signal is reduced to zero (or a predetermined threshold).

As a result, unnecessary vibration of the vibrator 72 in the X-axis direction is eliminated, and the offset temperature drift of the angular velocity sensor can be reduced as in the above embodiment.
In the case of the quadrangular prism-shaped vibrator 72 fixed at the nodes of the vibration so that both ends are free as in this embodiment, the ridge portion near the center where the drive electrodes 82a and 82b are formed is provided. Should be trimmed.

Next, the vibrator 100 of the angular velocity sensor shown in FIGS.
This is a so-called four-leg tuning fork in which two sets of tuning forks 5 and 106 with different intervals are combined, and a tuning fork with a narrow interval between the arms 103 and 104 is arranged between one tuning fork with a wide interval between the arms 105 and 106. Thus, the connecting portions of the tuning forks are connected (comb shape). As in the case of the vibrator 2 shown in FIG. 1, a supporter 107 having a torsion beam 108 in the center is formed of an adhesive material or the like for the connecting portion 102 of the vibrator 100 in the same manner as the vibrator 2 shown in FIG. And the supporter 107 further includes
Through a spacer 110 in order to arrange 106 in parallel at a position separated by a certain distance from the base 111,
It is fixed on the base 111 by welding or the like.

FIG. 11 is a perspective view showing the entire structure of the angular velocity sensor provided with the comb-shaped vibrator 100, and FIG.
FIG. 4 is an explanatory diagram showing a state in which the vibrator 100 is viewed from front and rear (X1 plane, X2 plane) and left and right (Y1 plane, Y2 plane).
The vibrator 100 is formed in a comb shape by, for example, machining PZT by dicing or the like. The four arms 103 to 10 constituting the vibrator 100
6, a pair of arm portions 10 constituting a central tuning fork portion.
The vibrator 100 is attached to each of the arm portions 103-1 to 3-4.
The electrodes for vibrating in the arrangement direction (Y-axis direction) of the pair 06 are formed, and a pair of arm portions 10 constituting an outer tuning fork portion are formed.
5 and 106, each arm portion 1 added to the vibrator 100 is provided.
Electrodes for detecting the angular velocity Ω around the Z-axis parallel to the central axes of 03 to 106 are formed.

That is, as shown in FIG.
The drive electrodes 112 and the monitor electrodes 113 are respectively formed on the X1 surface (the surface opposite to the base 111) of the X-rays 3 and 104, and the X2 surface (the back surface facing the base 111) is formed on the X3 surface. Temporary GND electrode 12 for grounding to a reference potential
0 is formed. And each of the arm portions 103, 10
4 drive electrode 112 and monitor electrode 113
Are connected to each other on the X1 plane of the connecting part 102, and are formed on the X2 plane of the arm parts 103 and 104, respectively.
The electrodes 120 are connected to each other on the X2 plane of the connection part 102.

On the other hand, a detection electrode 114 is formed on the X1 plane of the arm 105, a detection electrode 122 is formed on the X2 plane, and a Y1 plane, which is the outer side surface of the vibrator 100, is formed on the X1 plane.
A temporary GND electrode 125 is formed, and a short-circuit electrode 129 that connects (short-circuits) the detection electrodes 114 and 122 on the X1 and X2 planes is formed. The arm 10
6, a temporary GND electrode 115 is formed on the X1 plane,
A temporary GND electrode 121 is formed on the surface, and the vibrator 100
The detection electrode 124 is formed on the Y2 surface, which is the outer side surface of the X-ray, and the provisional GND electrodes 115 and 12 on the X1 and X2 surfaces.
1 are connected to each other (short-circuit).

Next, a pad electrode 116 for extracting a detection signal is formed on the X1 surface of the connecting portion 102. The pad electrode 116 is connected to the X1 surface of the arm portion 105 via an extraction electrode 118. The arm portion 106 is connected to the formed detection electrode 114 and is connected to the arm portion 106 via the extraction electrode 126.
Is connected to the detection electrode 124 formed on the Y2 plane. A pad electrode 117 for grounding a temporary GND electrode is also formed on the X1 plane of the connecting portion 102. The pad electrode 117 is connected to the arm portion 1 via an extraction electrode 119.
The temporary GND electrode 115 formed on the X1 plane of No. 06 is connected. The temporary GND electrode 121 of the arm 106 connected to the temporary GND electrode 115 is connected to the connecting portion 1.
02 through the extraction electrode 123 formed on the X2 plane and the extraction electrode 127 formed on the Y1 plane of the arm 105.
Temporary GND electrode 12 formed on Y1 surface of arm 105
5 and the provisional GND electrodes 120 formed on the X2 plane of the arm portions 103 and 104 are connected to each other.

Then, as shown in FIG.
Reference numeral 1 denotes a drive electrode 1 formed on the X1 plane of the connecting portion 102.
12, four terminals T31 to T3 corresponding to the monitor electrode 113, the pad electrode 116, and the pad electrode 117.
4 and each of these electrodes and each terminal T3.
1 to T34 are connected by bonding wires W31 to W34, respectively. The vibrator 1
The procedure for forming the electrodes on each surface of 00 is exactly the same as that of the vibrator 2 shown in FIG.

When detecting the angular velocity by using the angular velocity sensor thus configured, the driving arm 10
By applying a drive signal (AC voltage) between the drive electrode 112 formed on the third and fourth electrodes 104 and the provisional GND electrode 120, the inner tuning fork formed by the arms 103 and 104 is driven left and right. By controlling the drive signal using a control circuit (not shown) so as to resonate in the axial direction (Y-axis direction shown in the drawing) and to keep the output from the monitor electrode 113 constant, the tuning fork inside the vibrator 100 is formed. The part is self-oscillated. When the vibrator 100 is self-excited and oscillated in this manner, when an angular velocity Ω about the longitudinal central axis (Z axis) of the vibrator 100 is input,
The arms 103 and 104 also vibrate in the X-axis direction (detection axis direction) penetrating the X1 and X2 planes by Coriolis force. Then, each arm part 1 constituting the outer tuning fork part
05, 106 also vibrate in the X-axis direction, and the detection electrodes 114, 1
22 and the provisional GND electrode 125 and the detection electrode 12
4 and the provisional GND electrodes 115 and 12170, a current proportional to the vibration in the X-axis direction flows. By converting the current between these electrodes into a voltage value, the angular velocity Ω around the Z-axis is changed. To detect.

When adjusting the vibrator 100 of this embodiment, an AC voltage having a resonance frequency (detection frequency) in the detection axis direction of the vibrator 100 is applied as a drive signal, as in the above-described embodiment. , Then the detection electrodes 114, 122, 1
The detection signal obtained through the monitor 24 is monitored, and the ridge line of the vibrator 100 is trimmed so that the level (amplitude) of the detection signal becomes zero (or less than a predetermined threshold). As a result, unnecessary vibration of the vibrator 100 in the detection axis direction is eliminated, and the offset temperature drift of the angular velocity sensor can be reduced as in the above embodiment. The ridge line to be trimmed may be on the outside or inside as long as it is a ridge line of each of the arm portions 103 to 106.

Next, the vibrator 200 of the angular velocity sensor shown in FIG.
Each of the tuning forks has an H-shape connected at a connecting portion 202 such that the reference numerals 3, 204 and 205, 206 face in opposite directions. The vibrator 200 is formed in an H-shape by machining PZT by dicing or the like, and the vibrator 200 is attached to the pair of arms 203 and 204 forming one tuning fork. An electrode for vibrating in the arrangement direction (Y-axis direction) is formed, and a pair of arms 205 and 206 constituting the other tuning fork are provided with the arms 203 to 206 applied to the vibrator 200.
An electrode for detecting the angular velocity around the z-axis parallel to the central axis of is formed.

That is, the drive electrode 207 and the monitor electrode 208 are formed on the X1 surface (one surface of the vibrator 200 having an H shape) of the arm portions 203 and 204. Then, the drive electrode 20 of each arm 203, 204
7 and the monitor electrode 208 are connected to each other at the connection portion 202. Further, temporary GND electrodes 210 and 211 are formed on the X1 surface of the arm portions 205 and 206, respectively.
The detection electrodes 212 and 21 are provided on the Y1 and Y2 planes (outer side surfaces of the vibrator 200 in the respective arm portions 205 and 206).
3 are formed.

The X2 plane of the vibrator 200 (vibrator 20
0), an arm 2
03 and 204 through the connecting portion 202 and the arm portion 20
Temporary GND electrodes 209 are formed over substantially the entire area extending to the arm portions 205 and 206. The temporary GND electrodes 210 and 211 formed on the X1 plane of the arm portions 205 and 206
Short-circuit electrodes 21 formed on the Y1 and Y2 planes 206
8, 219 are connected to the temporary GND electrode 209 on the X1 plane. Further, pad electrodes 214 and 215 for extracting a detection signal are formed on the X1 surface of the connection portion 202, and the detection electrodes 212 and 213 formed on the Y1 and Y2 surfaces of the arm portions 205 and 206 are connected to the extraction electrode 216. , 217 are connected to the pad electrodes 214, 215, respectively.

When detecting the angular velocity using the vibrator 200 having such a configuration, for example, the X
At the same time as fixing the two surfaces on the base via the supporter,
The temporary GND electrode 209 on the X2 plane is grounded to the reference potential. Then, the drive electrodes 2 formed on the arm portions 203 and 204 are formed.
07 and the provisional GND electrode 209, a drive signal (AC voltage) is applied between these arm portions 103, 1
The drive signal is generated by using a control circuit (not shown) so that the tuning fork formed by the drive circuit 04 resonates in the left and right drive axis directions (Y axis direction shown in the figure) and the output from the monitor electrode 208 becomes constant. By performing the control, the tuning fork inside the vibrator 200 is caused to self-oscillate.

When an angular velocity Ω about the Z-axis is input during the self-excited control oscillation of the vibrator 200, the arms 203 and 204 are moved to the X1 and X2 planes by Coriolis force. Vibrates also in the X-axis direction (not shown) penetrating through. Then, each of the arm portions 2 constituting the other tuning fork portion
05 and 206 also vibrate in the X-axis direction.
2 and the provisional GND electrodes 209 and 210, and between the detection electrode 213 and the provisional GND electrodes 209 and 211, X
A current proportional to the axial vibration flows. Then, this current is taken out through the pad electrodes 214 and 215 and converted into a voltage value, thereby detecting the angular velocity Ω around the Z axis.

When adjusting the vibrator 200 of this embodiment, as in the above-described embodiment, the vibrator 2 is used as a drive signal.
An AC voltage having a resonance frequency (detection frequency) in the direction of the detection axis of 00 is applied, and the detection signal obtained through the detection electrodes 212 and 213 at that time is monitored, and the level (amplitude) of the detection signal is zero (or a predetermined value). The edge of the vibrator 200 is trimmed so that the threshold value is equal to or less than the threshold value. As a result, the vibrator 2
Unnecessary vibration in the detection axis direction of 00 is eliminated, and the offset temperature drift of the angular velocity sensor can be reduced as in the above embodiment. The ridge line to be trimmed may be on the outside or inside as long as it is a ridge line of each of the arm portions 203 to 206.

Next, in the above-described embodiment, the vibrator 2 including the vibrators 52, 72, 100, and 200 shown in FIGS. Although the angular velocity sensor in which the drive electrode and the detection electrode are formed on the outer wall of the piezoelectric body has been described, the vibrator itself is formed in a tuning fork or prismatic shape with metal, and the piezoelectric body for driving and detecting is attached to the outer wall. Even in the case of a sensor, the same effects as in the above embodiment can be obtained by applying the method of the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of an angular velocity sensor according to an embodiment including a tuning-fork-shaped vibrator.

FIG. 2 is an explanatory diagram showing electrodes formed on the vibrator shown in FIG.

FIG. 3 is an explanatory diagram illustrating a configuration of an adjustment system used for adjusting a vibrator.

FIG. 4 is an explanatory diagram for explaining a method of trimming a vibrator.

FIG. 5 is an explanatory diagram illustrating an adjustment procedure by trimming a vibrator.

FIG. 6 is an explanatory diagram showing measurement results of a change in amplitude of a detection signal and a change in offset temperature drift due to trimming of a vibrator.

FIG. 7 is an explanatory diagram illustrating a relationship between a trimming amount of a transducer and a change in amplitude of a detection signal and a change in offset temperature drift.

FIG. 8 is an explanatory diagram illustrating another configuration example of an adjustment system used for adjusting a vibrator.

FIG. 9 is an explanatory diagram showing a configuration of an angular velocity sensor provided with a prism-shaped vibrator having one end fixed, and electrodes formed on the vibrator.

FIG. 10 is an explanatory diagram showing a configuration of an angular velocity sensor provided with a prism-shaped vibrator fixed at nodes of vibration so that both ends are free, and an electrode formed on the vibrator.

FIG. 11 is an explanatory diagram illustrating a configuration of an angular velocity sensor including a comb-shaped vibrator having two sets of tuning forks.

FIG. 12 is an explanatory view showing electrodes formed on the comb-shaped vibrator shown in FIG.

FIG. 13 is an explanatory diagram illustrating a configuration of an H-shaped vibrator having two sets of tuning forks.

[Explanation of symbols]

2, 52, 72, 100, 200 ... vibrator, 4, 6, 1
03-106, 203-206 ... arm part, 8,10
2,202... Connection part, 12a, 12b, 58a, 58
b, 82a, 82b, 112, 207 ... drive electrodes (drive means), 14a, 14b, 60, 84a, 84b, 11
3,208... Monitor electrodes, 16a, 16b, 24, 6
2,70,86a, 86b, 94,115,120,1
21, 125, 209, 210, 211 ... temporary GND electrode, 18a, 18b, 64, 88a, 88b ... electrode for polarization, 20a, 20b, 66, 90a, 90b, 116,
117, 214, 215: pad electrode, 22a, 22
b, 68, 92a, 92b, 114, 122, 124,
212, 213 ... detection electrodes (detection means), 26a, 26
b, 28a, 28b, 62a, 62b, 96a, 96
b, 98a, 98b, 128, 129, 218, 219
... Electrode for short circuit 30a, 30b, 66, 99a, 99
b, 118, 119, 123, 126, 127, 21
6,217 ... extraction electrode, 32,54,74,75,10
7 supporter, 40 oscillator, 42 inverting circuit, 44,
44a, 44b ... current-voltage conversion circuit, 46 ... oscilloscope.

Claims (11)

[Claims] 1. A vibrator having a vibrating portion formed in the shape of a prism and exciting the vibrator in a driving axis direction orthogonal to a central axis in a longitudinal direction of the vibrating portion by a driving signal input from the outside. An angular velocity sensor comprising: a driving unit that performs vibration and a detection unit that detects vibration that occurs in a detection axis direction orthogonal to the drive shaft in the vibrating unit. The angular velocity sensor generates in the detection axis direction when the driving unit excites the vibrator. An adjustment method for adjusting vibration characteristics of the vibrator in order to suppress unnecessary vibration of the vibrating unit, wherein the driving unit uses an AC voltage corresponding to a resonance frequency of the vibrating unit in a direction of the detection axis as the driving signal. The vibration characteristic of the vibrator is adjusted so that the vibrator is vibrated by inputting the vibration signal so that the amplitude of a detection signal obtained by the detection means at that time becomes small. Adjustment method of that angular velocity sensor. 2. The method for adjusting an angular velocity sensor according to claim 1, wherein the adjustment of the vibration characteristic is performed by cutting a part of the vibrator. 3. The adjustment of the angular velocity sensor according to claim 2, wherein the adjustment of the vibration characteristic is performed by cutting at least one of the ridges of the vibrator along the longitudinal direction of the vibrating part. Method. 4. The vibrator is a vibrator formed in a tuning fork shape by a pair of arms as the vibrating portion and a connecting portion connecting one end of each arm to each other, and adjusting the vibration characteristics. 4. The method according to claim 3, wherein the cutting is performed by cutting at least one of ridges along the longitudinal direction of the pair of arms. 5. In the angular velocity sensor, the vibrator includes two sets of tuning fork portions each including a pair of arm portions as the vibrating portion and a connecting portion connecting one end of each of the arm portions to each other. Are formed in a comb-shape or H-shape by integrating and connecting the connecting portions of the arms, and the driving means is configured such that each of the arm portions constituting one tuning fork portion has a drive shaft orthogonal to the central axis in the longitudinal direction of each of the arm portions. And the detecting means is configured to detect a vibration occurring in a detection axis direction orthogonal to the drive shaft in each of the arm portions constituting the other tuning fork portion. 4. The method for adjusting an angular velocity sensor according to claim 3, wherein the adjustment is performed by cutting at least one of the ridges along the longitudinal direction of the arms constituting the two sets of tuning forks. 6. The vibration characteristic is adjusted by cutting any one of a ridgeline near the connecting portion of the arm portion, a ridgeline of the connecting portion, and a ridgeline from near the connecting portion of the arm portion to the connecting portion side. The method for adjusting an angular velocity sensor according to claim 4, wherein the adjustment is performed. 7. The vibrator includes one vibrating portion having one end of a prism fixed, and the adjustment of the vibration characteristics is performed by cutting a ridgeline near the fixed portion of the vibrating portion. The method for adjusting the angular velocity sensor according to claim 3. 8. The vibrator includes one vibrating part having a portion serving as a node at the time of vibration so that both ends of the prism are free, and the vibration characteristics are adjusted in the longitudinal direction of the vibrating part. The method for adjusting an angular velocity sensor according to claim 3, wherein the adjustment is performed by cutting a ridgeline near the center. 9. The angular velocity sensor adjusting method according to claim 3, wherein the adjustment of the vibration characteristic is performed by adjusting a length of cutting the ridge line. 10. The method for adjusting an angular velocity sensor according to claim 3, wherein the adjustment of the vibration characteristic is performed by adjusting a depth at which the ridge is cut. 11. The method according to claim 1, wherein the vibrator is made of a piezoelectric material.