JP2001194150A - Angular velocity detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity detecting apparatus of high sensitivity using a vibrating beam shaped to maximize sensitivity to angular velocity, by coinciding a resonant frequency in the direction of exciting vibration with a resonant frequency in the direction in which Coriolis force is generated, while eliminating mechanical coupling. SOLUTION: In the angular velocity detecting apparatus, a first lithium tantalate piezoelectric element 2 and a second lithium tantalate piezoelectric element 3, which are polarized in opposite directions, are laminated together to provide a bimorph structure vibrating beam 1 in the form of a rectangular solid, the vibrating beam 1 being supported at both ends. The vibrating beam 1 is shaped so that the value of thickness t of the vibrating beam 1 is greater than the value of width W thereof and the shape ratio W/t of the width W to the thickness t is not less than 0.864 nor more than 0.957. The vibrating beam 1 is frequency adjusted by laser trimming so that while mechanical coupling is avoided, the resonant frequency in the direction of exciting vibration coincides with the resonant frequency in the direction in which Coriolis force is generated. Thus, the vibrating beam 1 can be machined to have maximum sensitivity to angular velocity.

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 and an application device thereof, and more particularly, to a vibration type angular velocity detecting device for detecting a Coriolis force in accordance with an angular velocity by vibrating a vibrating body, and a camera shake using the same. Camera with prevention function,
It relates to a car navigation system and a car.

[0002]

2. Description of the Related Art A conventional angular velocity detecting device is disclosed, for example, in Japanese Patent Application Laid-Open No. 7-332988. An angular velocity detection sensor having a structure advantageous for adjusting the resonance frequency of such a vibrating beam is disclosed in Japanese Patent Application Laid-Open No. 10-19578.

[0003]

However, the above-mentioned Japanese Patent Application Laid-Open No.
JP-A-332988 does not specifically describe the shape of the vibrating beam having the maximum sensitivity to angular velocity. On the other hand,
As shown in Japanese Patent Application Laid-Open No. 10-19578, in general, in order to maximize the sensitivity to angular velocity in a certain element (including the vibrating beam disclosed in Japanese Patent Application Laid-Open No. 7-332988), it is necessary to add the element. It is necessary to match the resonance frequency in the vibration direction with the resonance frequency in the direction in which Coriolis force is generated.

In the vibrating beam disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-332988, the resonance frequencies in each direction can be matched by matching the second moment of area in each direction.
However, when the width and thickness of the vibrating beam are matched to match the second moment of area, a phenomenon called mechanical coupling occurs, and despite vibrating the vibrating beam in the excitation direction, It also vibrates in the direction in which Coriolis forces are generated. Therefore, in the prior art, it is not possible to vibrate only in the vibration direction.

As the piezoelectric material used for the vibrating beam, there are a powder sintered body such as lead zirconate titanate PZT or ceramics, and a single crystal such as quartz or lithium tantalate LT. Of these, lithium tantalate has higher sensitivity than PZT, but is significantly affected by mechanical coupling, and it has been conventionally difficult to use it for a vibrating beam.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vibrating beam having a shape in which the resonance frequency in the direction of vibration and the resonance frequency in the direction in which Coriolis force is generated are matched while eliminating the mechanical coupling, and the sensitivity to angular velocity is maximized. An object of the present invention is to provide an angular velocity detecting device using the same.

Another object of the present invention is to provide a camera, a car navigation system, and a car to which the angular velocity detecting device is applied.

[0008]

In order to achieve the above object, the present invention provides an angular velocity detecting device for detecting Coriolis force according to an angular velocity by a doubly supported vibrating beam. A vibrating beam having a rectangular parallelepiped bimorph structure in which a polarized first lithium tantalate piezoelectric body and a second lithium tantalate piezoelectric body polarized in a direction opposite to the polarization direction of the first piezoelectric body are stacked. And an angular velocity detecting device in which the thickness t of the vibrating beam is larger than the width W of the vibrating beam.

In order to achieve the above object, the present invention also provides an angular velocity detecting device for detecting a Coriolis force in accordance with an angular velocity by a doubly supported vibrating beam.
Vibration of a rectangular parallelepiped bimorph structure in which a first lithium tantalate piezoelectric material polarized in the thickness direction and a second lithium tantalate piezoelectric material polarized in a direction opposite to the polarization direction of the first piezoelectric material are stacked. And the thickness t of the vibrating beam is larger than the width W of the vibrating beam, and the shape ratio W of the width W to the thickness t is W
We propose an angular velocity detector in which / t is 0.864 or more and 0.957 or less.

According to another aspect of the present invention, there is provided an angular velocity detecting apparatus for detecting a Coriolis force corresponding to an angular velocity by at least two doubly supported vibrating beams arranged so that their longitudinal directions are orthogonal to each other. The present invention proposes a camera provided with a device and an image stabilizing unit for correcting camera shake based on the output of the angular velocity detecting device, and adopting any one of the angular velocity detecting devices.

According to another aspect of the present invention, a Coriolis force corresponding to an angular velocity is detected by at least two doubly supported vibrating beams arranged so that their longitudinal directions are orthogonal to each other. In a car navigation system including an angular velocity detecting device and means for detecting a traveling direction of a vehicle based on an output of the angular velocity detecting device, a car navigation system employing any of the angular velocity detecting devices is proposed.

According to the present invention, in order to attain the above object, Coriolis force corresponding to the angular velocity is detected by at least two doubly supported vibrating beams arranged so that their longitudinal directions are orthogonal to each other. The present invention proposes an automobile having an angular velocity detecting device and means for controlling the attitude of the vehicle based on the output of the angular velocity detecting device, and employing any one of the angular velocity detecting devices.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, referring to FIGS.
An embodiment of an angular velocity detecting device according to the present invention and its applied equipment will be described.

[0014]

Embodiment 1 FIG. 1 is an exploded view showing an element portion of an angular velocity detecting device according to Embodiment 1 of the present invention. However, the package portion and the cover are omitted, and circuit portions such as an amplifier circuit are not shown.

The Z axis is a vibration direction, the Y axis is a detection direction, that is, a direction in which Coriolis force is generated, and an angular velocity ω is applied around the X axis.

The element portion is roughly divided into a vibrating beam 1 vibrating in the Z-axis direction for detecting an angular velocity, a first suspension 9, a second suspension 16, and a fixed base made of an insulator. 15 When these are assembled, the element section of the angular velocity detecting device is completed.

The main surface of the first piezoelectric substrate 2 of the vibrating beam 1 is 4
The first suspension 9 is provided by the connection arm 12 at the location.
, And the outer frame 11 of the first suspension 9 is fixed to the fixing base 15 with an adhesive. The main surface of the second piezoelectric substrate 3 of the vibrating beam 1 is fixed to the second suspension 16 by four connection arms 17. The outer frame 18 of the second suspension 16 has four connection arms 1.
By 7, it is fixed to the fixed base 15.

The main surface of the first piezoelectric substrate 2 and the four connection arms 12 are connected at nodes where the doubly supported beam performs primary flexural resonance vibration in the Z-axis direction. Similarly,
The main surface of the second piezoelectric substrate 3 and the four connection arms 17 are connected at nodes where the doubly supported vibrating beam 1 performs primary flexural resonance vibration in the Z-axis direction. The vibrating beam 1
The first suspension 9 and the second suspension 16 are supported so as to sandwich them.

Since the first suspension 9 and the second suspension 16 have the same structure, the structure of the suspension will be described using the first suspension 9 as an example. The first suspension 9 includes an outer frame 11 and two inner frames 10, and the outer frame 11 and the inner frame 10 are connected by a connection portion 14. Each inner frame 10 has a connecting arm 12
Are formed, and the first suspension 9 includes:
A total of four connecting arms 12 are formed. The vibrating beam 1 is supported at four places by these connection arms 12.

Each inner frame 10 has a connecting arm 12
A bent spring 13 bent in a U-shape is formed therebetween. For this reason, when the vibrating beam 1 bends and vibrates in the Y-axis direction, the vibration is not hindered by the first suspension 9 and the vibrating beam 1 is moved in the Y-axis direction while being free from vibration. 9 supported. Also,
Since the thickness thereof is thinner than the width of the connection portion 14 and the inner frame 10, the first suspension 9 can support the vibrating beam 1 in a state where it can freely vibrate in the Z-axis direction. When the first suspension 9 having such a shape is used, in a state where the vibrating beam 1 constantly performs primary bending resonance vibration in the Z-axis direction, when the angular velocity ω is applied around the X-axis, the vibration is synchronized with the vibration. Of the vibrating beam 1
It does not restrain the Coriolis force generated in the axial direction.

FIG. 2 is an oblique view of the front side and the back side of the vibrating beam 1. The vibrating beam 1 includes a first piezoelectric substrate 2
, A second piezoelectric substrate 3, and an intermediate layer 4, and the first piezoelectric substrate 2 and the second piezoelectric substrate 3 are joined to each other via the intermediate layer 4. Further, the first piezoelectric substrate 2
A metal thin film is previously formed on the main surface and the sub surface of the second piezoelectric substrate 3. Among them, the first piezoelectric substrate 2
The dividing pattern 5 divides the thin-film electrode into two only on the main surface of, and the first thin-film electrode 6 and the second thin-film electrode 7 are formed. A third thin film electrode 8 is formed on the entire main surface of the second piezoelectric substrate 3.

These thin-film electrodes only need to have conductivity,
Au / Cr thin film, Au / Ti thin film, Pt / Ti thin film, A
A u / Pt / Ti thin film, Ni / Ti thin film, or the like is used.
Under the Au thin film, Pt thin film and Ni thin film,
The reason why the i-thin film is formed is to enhance the adhesion between the underlying first and second piezoelectric substrates 2 and 3 and the Au, Pt, and Ni thin films. The intermediate layer 4 may be, for example, an epoxy-based adhesive layer or a Sn-Pb solder layer. Further, the first piezoelectric substrate 2 and the second piezoelectric substrate 3 used here are single-crystal lithium tantalate piezoelectric substrates of 130 ° rotation Y-cut, and are polarized in the thickness direction in opposite directions. . Here, the width of the vibrating beam 1 is denoted by W, and the thickness is denoted by t.

FIG. 3 is a view for explaining the principle of vibrating the vibrating beam 1 in the Z-axis direction. The polarization directions of the first piezoelectric substrate 2 and the second piezoelectric substrate 3 are opposite to each other along the thickness direction, as indicated by arrows. The first piezoelectric substrate 1 and the second piezoelectric substrate 3 are joined via the intermediate layer 4 so as to have such a relationship.

An AC voltage 19 is applied to the third thin-film electrode 8 (see FIG. 2), the first thin-film electrode 6 and the second thin-film electrode 7 formed on the main surface of the second piezoelectric substrate 3. By applying this voltage, the first piezoelectric substrate 2 extends in the X-axis direction as indicated by an arrow, and the second piezoelectric substrate 3 contracts in the X-axis direction as indicated by an arrow. When the polarity of the applied voltage is reversed, the first piezoelectric substrate 2 contracts in the X-axis direction, and the second piezoelectric substrate 3 extends in the X-axis direction. A series of operations is repeated according to the frequency of the applied voltage. As a result of this operation, the vibrating beam 1 having the bimorph structure supported at both ends flexurally vibrates at a speed V in the Z-axis direction.

If the frequency of the AC voltage 19 becomes a resonance frequency that causes the vibrating beam 1 to undergo primary bending resonance vibration in the Z-axis direction, the velocity V in the Z-axis direction shows the maximum value and at the same time, The displacement at the central portion in the longitudinal direction (the portion serving as the antinode of the primary resonance vibration) indicates the maximum displacement. At this time,
When the angular velocity ω is applied around the X axis, a Coriolis force Fc is generated in the Y axis direction of the vibrating beam 1 in synchronization with the bending vibration in the Z axis direction. When the Coriolis force Fc is applied, the bending vibration in the Z-axis direction becomes an oblique bending vibration having a certain angle with respect to the Z-axis.

FIG. 4 shows an AA cross section of the center of the vibrating beam 1 in the longitudinal direction in FIG. In FIG. 4, the intermediate layer 4 is shown separately for each layer for easy understanding. The intermediate layer 4 includes a fourth thin film electrode 20 formed on the entire sub surface of the first piezoelectric substrate 2 and a fifth thin film electrode formed on the entire sub surface of the second piezoelectric substrate 3. 21
And an adhesive layer 22.

Here, since the vibrating beam 1 is vibrated at the resonance frequency in the Z-axis direction, if the resonance frequency in the Y-axis direction of the vibrating beam 1 matches the resonance frequency in the Z-axis direction, the Coriolis force Fc , The displacement in the Y-axis direction when oblique bending vibration occurs is maximized. When the displacement in the Y-axis direction is maximum, the strain in the Y-axis direction generated on the first piezoelectric substrate 2 is maximum. For example, when the vibrating beam 1 is bent in the negative direction of the Y-axis, the portion of the first piezoelectric substrate 2 sandwiched between the first thin film electrode 6 and the fourth thin film electrode 20 has the maximum elongation, that is, the maximum tension. The portion of the first piezoelectric substrate 2 sandwiched between the second thin-film electrode 7 and the fourth thin-film electrode 20 exhibits a maximum contraction, that is, a maximum compressive stress.

This expansion and contraction causes the first thin film electrode 6
And a potential −V is generated at the second thin-film electrode 7. In this manner, the potential V having the maximum absolute value is generated between the first thin film electrode 6 and the second thin film electrode 7,
The vibrating beam 1 will obtain the maximum sensitivity. As a result, when the resonance frequency in the Z-axis direction, which is the vibration direction, and the resonance frequency in the Y-axis direction, which is orthogonal to the direction and which is the detection direction, match, the detection sensitivity of the vibrating beam 1 can be maximized.

Z of bi-supported vibrating beam 1 with bimorph structure
It is known that the resonance frequencies in the axial direction and the Y-axis direction are represented by the following equation: f = {α ² / (2πl ² )} · {(EI / DA)} Here, f is the resonance frequency in each direction, I is the second moment of area of the vibrating beam 1, E is the Young's modulus of the vibrating beam 1, D is the density of the vibrating beam 1, A is the cross-sectional area of the vibrating beam 1, and α is the resonance. This is a constant depending on the mode (primary vibration mode: 4.73).

As is clear from this equation, in order to make the resonance frequency in the Z-axis direction coincide with the resonance frequency in the Y-axis direction, the secondary moment of area of the vibrating beam 1 around the Z-axis and the vibration around the Y-axis are required. What is necessary is just to make the second moment of area of the beam 1 coincide. That is, it is only necessary to make the values of the width W and the thickness t coincide.

However, when the width W and the thickness t are made as close as possible, and the resonance frequencies in each direction are made as close as possible, the vibration in the Z-axis direction so as to draw the vibration locus 23 Vibration in the excitation direction leaks in the Y-axis direction, which is the detection direction, and leakage vibration due to mechanical coupling, which is coupled vibration, is induced. Due to this mechanical coupling, the vibrating beam 1 draws a vibration locus 24 of oblique vibration. Under the influence, the Coriolis force due to the angular velocity cannot be accurately detected.

Here, a value called a coupling ratio is introduced as an amount representing the mechanical coupling. This coupling ratio is represented by (amplitude in the Y-axis direction / amplitude in the Z-axis direction) when the vibrating beam 1 is vibrated in the Z-axis direction.

FIG. 5 shows an example of an experimental apparatus for measuring the coupling ratio. In order to measure the vibration amplitude of the vibrating beam 1 in the Z-axis direction and the Y-axis direction, a two-channel laser Doppler vibrometer is used. That is,
In order to measure the vibration amplitude in the Z-axis direction, the laser is used to measure the vibration amplitude in the Y-axis direction using the lens 28 of the channel 1 to which the laser is output and the laser Doppler vibrometer 27 of the channel 1. A channel 29 lens 29 and a channel 2 laser Doppler vibrometer 26 are used. Those laser Doppler vibrometers 27 and 2
6, the output signal corresponding to the vibration state of the vibrating beam 1 is F
It is input to the FT analyzer 25. FFT analyzer 2
5 analyzes those signals. The element 32 provided with the vibrating beam 1 is placed on the holder 31 on the vibration isolator 30 and measured.

According to the above experimental apparatus, the coupling ratio can be measured. Using the experimental apparatus shown in FIG. 5, the relationship between the width W of the vibrating beam 1 and the coupling ratio was examined in order to eliminate the influence of the mechanical coupling.

FIG. 6 shows the relationship between the width W of the vibrating beam 1 and the coupling ratio when the thickness t of the vibrating beam 1 is 1.014 mm. It was found that if the width W of the vibrating beam 1 is 0.970 mm or less, the coupling ratio becomes 6% or less, and a vibration locus such as the vibration locus 23 in the Z-axis direction is obtained.

FIG. 7 is a graph showing the relationship between the width W of the vibrating beam 1 and the resonance frequency difference. The width W of the vibrating beam 1 is 0.970m
m, the resonance frequency difference was about 1400 Hz.
From the results shown in FIG. 7, it can be seen that the smaller the element width W, the larger the resonance frequency difference. As described above, if the resonance frequency in the Z-axis direction and the resonance frequency in the Y-axis direction are matched, the detection sensitivity of the vibrating beam 1 can be maximized. For this reason, the vibration beam 1 was trimmed using a YAG laser to adjust the frequency.

FIG. 8 shows the vibrating beam 1 and the connecting arm 17 of the second suspension. As shown in FIG. 8, on the main surface of the second piezoelectric substrate 3 on which the third thin film electrode 8 is formed,
A laser trimming groove 33 is formed. The laser trimming groove 33 is formed parallel to the width direction of the second piezoelectric substrate 3 so as not to change the coupling ratio before trimming. A plurality of laser trimming grooves 33 may be formed as shown in FIG. 8, and the depth and width of the laser trimming grooves 33 are
It can be changed according to the frequency adjustment amount.

FIG. 9 shows the result of frequency adjustment of the vibrating beam 1 having a coupling ratio of 6% by laser trimming. The horizontal axis is the volume removal rate by laser trimming, and the vertical axis is the resonance frequency difference. As shown in FIG.
If the volume removal rate is increased, the resonance frequency in each direction can be matched. Even when the resonance frequencies in the respective directions matched, the coupling ratio at that time was almost the same as the coupling ratio before laser trimming.

Further, such frequency adjustment is performed at 5000 Hz.
To the extent that it was easily achieved, there was no problem in production efficiency. When the frequency difference is 5000 Hz, the width W of the vibrating beam 1 is 0.876 mm, and the coupling ratio is 6% or less.

As described above, in consideration of the frequency adjustment, so-called easy matching, and the production efficiency, the lower limit of the shape ratio W / t between the width W and the thickness t of the vibrating beam 1 is determined, and the required resonance frequency difference is determined. Is considered, the upper limit of the shape ratio W / t is determined.

After all, the shape ratio W / t is 0.864 or more and 0.957 or more.
If below, mechanical coupling does not occur,
The vibrating beam 1 can vibrate in an exciting vibration direction. Further, when the frequency is adjusted by laser trimming, the resonance frequency in the direction of the excitation vibration and the resonance frequency in the direction in which the Coriolis force is generated can be easily matched, and the vibrating beam 1 having the maximum sensitivity to the angular velocity can be obtained. .

FIG. 10 is a diagram showing a configuration of an angular velocity detecting system of the angular velocity detecting device according to the present invention. An oscillation circuit 34 for applying an AC voltage for oscillating the vibrating beam 1 at a resonance frequency in the Z-axis direction between the first thin film electrode 6 and the second thin film electrode 7 and the third thin film electrode 8 is provided. A differential amplifier circuit 35 for differentially amplifying the potential difference between the thin film electrode 6 and the second thin film electrode 7 is provided. Further, in order to extract a potential difference proportional to the Coriolis force, the synchronous detection circuit 36 and the DC amplification circuit 3
7 and the like are provided. While the angular velocity detecting device is in the operating state, an alternating voltage is applied between the first thin-film electrode 6, the second thin-film electrode 7, and the third thin-film electrode 8 by the oscillation circuit 34. Vibrates in the Z-axis direction. However,
The frequency of this AC voltage is a frequency at which the vibrating beam 1 resonates in the Z-axis direction. The vibration speed at this time is V, and the mass of the vibrating beam is m.

In this state, when the angular velocity detector rotates at an angular velocity ω about the X axis, a Coriolis force Fc (= 2 mVω) corresponding to the angular velocity is generated in the Y-axis direction.
This Coriolis force Fc is applied in the Y-axis direction,
In the Y-axis direction.

The Coriolis force F in the negative Y-axis direction shown in FIG.
When c is applied, the potential generated at the first thin-film electrode 6 is changed to +
V, and the potential generated at the second thin-film electrode 7 is −V.
The potential generated at the first thin-film electrode 6 and the second thin-film electrode 7 is detected in a form in which a signal resulting from the vibration of the vibrating beam 1 is synthesized in addition to a signal accompanying the Coriolis force Fc. The signal due to the Coriolis force Fc is the first thin-film electrode 6
Since the sign is different between the second thin-film electrode 7 and the second thin-film electrode 7, if these values are input to the differential amplifier circuit 35 and the difference between them is taken, the signal caused by the vibration of the vibrating beam 1 is canceled out, and the Coriolis force F
Only the signal according to c can be read. A voltage signal obtained through a differential amplifier circuit 35 is detected by a synchronous detection circuit 36 based on the frequency of an oscillation circuit 34 that vibrates the vibrating beam 1 at the resonance frequency in the Z-axis direction. Further, the voltage is amplified by the DC amplifier circuit 37, and a voltage value based on the deflection due to the Coriolis force Fc is extracted as a voltage value proportional to the angular velocity ω.

The angular velocity is detected by using the above method. However, the configuration of the circuit in FIG. 10 is one embodiment, and the present invention is not limited to the circuit configuration as long as the vibrating beam 1 of the angular velocity detecting device according to the present invention shown in FIGS. .

FIG. 11 is a diagram showing a state where the vibrating beam 1, the first suspension 9, the fixed base 15, and the second suspension 16 of the angular velocity detecting device shown in FIG. 1 are assembled. In a state where these are assembled, the first thin film electrode 6 and the second thin film electrode 7 and the first suspension 9 conduct, and the third thin film electrode 8 and the second suspension 16
(See FIGS. 2 and 1). Therefore, a part of the first suspension 9 indicated by a broken line BB is
The first thin film electrode 6 and the second thin film electrode 7 are electrically separated by cutting using a laser. A connection line a connected to the first thin-film electrode 6, a connection line b connected to the second thin-film electrode 7,
When the external thin film electrode 8 is connected to an external oscillation circuit 34 and a differential amplifier circuit 35 through a connection line c or the like,
The vibrating beam 1 can be actually operated.

[0047]

[Embodiment 2] Fig. 12 is a view showing a state in which a part of a video camera in which two angular velocity detecting devices according to the present invention are arranged so that their longitudinal directions are orthogonal to each other is cut.
The video camera according to the second embodiment is roughly classified into a video tape mounting unit 111, a camera unit 114, an audio input unit 116, and a finder unit 112. Camera unit 1
Reference numeral 14 denotes the lens unit 113 and the substrate 1 on which the angular velocity detection sensor is mounted.
15 are included.

FIG. 13 shows the lens section 113 and the angular velocity detection sensor mounting board 115 of FIG. An angular velocity detecting device 121 for detecting horizontal camera shake and an angular velocity detecting device 122 for detecting vertical camera shake are mounted on the angular velocity detecting device mounting board 115. Although a detailed structure is not shown here, the mounting substrate 115 is fixed to the lens unit 113 by, for example, screws and is integrated. Therefore, the lens unit 113 is moved horizontally and / or
Alternatively, when moving in the vertical direction, the angular velocity detector mounting board 115 also moves at the same time, so that the angular velocities in each direction can be detected by the angular velocity detectors 121 and 122.

FIG. 14 shows a substrate 115 for mounting an angular velocity detecting device.
FIG. 3 is a view as viewed from the back side. Angular velocity detector 121, 1
Reference numeral 22 is arranged at a position as close as possible to the lens optical axis 132 at the lens outer diameter position 131, and furthermore, their longitudinal directions, that is, the X-axis are orthogonal to each other. However, since the angular velocity detector 121 and the angular velocity detector 122 are both vibration type angular velocity detectors, they are shifted by about 500 Hz so that the resonance frequencies do not interact.

Although the second embodiment has been described as applied to a video camera, it can be applied not only to a video camera but also to a still camera or a movie camera, and is also useful as a means for preventing camera shake of binoculars and telescopes.

In this embodiment, two angular velocity detectors are arranged so that their longitudinal directions are orthogonal to each other. However, three angular velocity detectors are arranged along the X, Y, and Z axes. Is also good. In this case, camera shake is detected three-dimensionally, and camera shake can be more strictly prevented.

[0052]

[Embodiment 3] Fig. 15 is a view showing a car equipped with a car navigation system in which at least two angular velocity detecting devices according to the present invention are arranged so that their longitudinal directions are orthogonal to each other. The passenger car 145 has an engine 141
And the car navigation system data processing unit 144
, An angular velocity detector 146, a GPS satellite signal receiving antenna 143 for receiving signals from GPS satellites, and a car navigation information display unit 1 for displaying data processing results
42 are mounted. The processing unit 144 provided in the passenger car 145 processes data from the antenna 143, data from the engine 141, data from the angular velocity detecting device 146 according to the present invention, and data from the wheels 147.

The car navigation system is a system for determining the position of a passenger car 145 based on a position signal from a GPS satellite and guiding the passenger to a destination. But G
Since the signal from the PS satellite has an error of several meters to several tens of meters, the system may erroneously recognize the current position on an intricate road or alley in an urban area.

In order to correct the error, the data processing unit 144 of the third embodiment uses data from at least two angular velocity detectors 146 arranged so that their longitudinal directions are orthogonal to each other. For example, when the passenger car 145 senses the rotation direction 148 of the passenger car, the data processing unit 144
Processes the movement data of the passenger car 145 based on the data from the angular velocity detecting device 146 and the data from the wheels 147. After that, the detailed behavior of the vehicle body is obtained based on the position information from the GPS satellite, and the corrected position is displayed on the information display unit 142.

[0055]

Fourth Embodiment Data from the angular velocity detector 146 of the third embodiment can be used as data for controlling the attitude of a vehicle. In this case, at least two angular velocity detecting devices arranged so that their longitudinal directions are orthogonal to each other;
A data processing unit 144 is provided as means for controlling the attitude of the vehicle based on the output of the angular velocity detection device.

Assuming that the X axis is the direction of travel of the vehicle, the object to be controlled is a vertical movement (bounce) along the Z axis of the vehicle, a pitching around the Y axis, a rolling around the X axis, a yawing around the Z axis, and the like. Is included.

The fourth embodiment includes, for example, three angular velocity detectors 146 arranged so that their longitudinal directions are orthogonal to each other along the X-axis, Y-axis, and Z-axis directions. Data processing unit 1
When detecting bounce, pitching, rolling, and yawing of the vehicle based on the outputs from the three angular velocity detectors 146, the controller 44 sends a signal to a suspension or a shock absorber to control the posture and the riding comfort of the vehicle.

[0058]

According to the present invention, since the thickness t of the vibrating beam of the vibrating beam applied to the angular velocity detecting device is made larger than the width W of the vibrating beam, the vibrating beam can be formed without mechanical coupling. Vibration can be performed in the vibration direction.
In addition, if the frequency of this vibrating beam is adjusted by laser trimming, the resonance frequency in the vibration direction and the resonance frequency in the direction in which Coriolis force is generated are matched without generating mechanical coupling, and the sensitivity to angular velocity is maximized. Can be processed into a vibrating beam. As a result, a highly sensitive angular velocity detecting device is obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an element portion of an angular velocity detecting device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a front side and a back side of a vibrating beam.

FIG. 3 is a diagram illustrating a principle of vibrating a vibrating beam in a Z-axis direction.

FIG. 4 is a cross-sectional view of the vibrating beam in FIG.
It is a figure showing a section.

FIG. 5 is a diagram showing an example of an experimental device for measuring a coupling ratio.

FIG. 6 is a diagram showing the relationship between the width W of the vibrating beam and the coupling ratio when the thickness t of the vibrating beam is 1.014 mm.

FIG. 7 is a graph showing a relationship between a width W of a vibrating beam and a resonance frequency difference.

FIG. 8 is a diagram showing a vibrating beam and a connection arm of a second suspension.

FIG. 9 is a diagram illustrating a result of frequency adjustment of a vibration beam having a coupling ratio of 6% by laser trimming.

FIG. 10 is a diagram showing a configuration of an angular velocity detection system of the angular velocity detection device according to the present invention.

11 is a diagram showing a state where the vibrating beam, the first suspension, the fixed base, and the second suspension of the angular velocity detecting device of FIG. 1 are assembled.

FIG. 12 is a perspective view showing a state in which a part of a video camera in which two angular velocity detecting devices according to the present invention are arranged so that their longitudinal directions are orthogonal to each other is cut away.

13 is a diagram showing a lens unit and an angular velocity detection sensor mounting board of the video camera of FIG.

14 is a view of the angular velocity detection device mounting board of FIG. 13 as viewed from the back side.

FIG. 15 is a diagram showing a passenger car mounted with a car navigation system in which at least two angular velocity detection devices according to the present invention are arranged so that their longitudinal directions are orthogonal to each other.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration beam 2 First piezoelectric substrate 3 Second piezoelectric substrate 4 Intermediate layer 5 Divided pattern 6 First thin film electrode 7 Second thin film electrode 8 Third thin film electrode 9 First suspension 10 First suspension Inner frame 11 Outer frame of first suspension 12 Connection arm of first suspension 13 Bending spring 14 Connecting portion 15 Fixed base 16 Second suspension 17 Connection arm of second suspension 18 Outer frame of second suspension 19 AC Voltage 20 Fourth thin film electrode 21 Fifth thin film electrode 22 Adhesive layer 23 Vibration trajectory 24 Oblique vibration trajectory 25 FFT analyzer 26 Channel 2 laser Doppler vibrometer 27 Channel 1 laser Doppler vibrometer 28 Channel 1 lens 29 Lens of channel 2 30 Anti-vibration table 31 Holder 32 Element 33 Re Trimming groove 34 Oscillation circuit 35 Differential amplification circuit 36 Synchronous detection circuit 37 DC amplification circuit 111 Video tape mounting unit 112 Finder unit 113 Lens unit 114 Camera unit 115 Angular velocity detection device mounting board 116 Audio input unit 121 For detecting horizontal camera shake Angular velocity detecting device 122 Angular velocity detecting device for detecting vertical camera shake 131 Lens outer diameter position 132 Lens optical axis 141 Engine 142 Car navigation information display unit 143 GPS satellite signal receiving antenna 144 Car navigation system data processing unit 145 Passenger car 146 Angular velocity detecting device 147 Wheel 148 Passenger car rotation direction

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuo Otsu 1 Kitano, Makino, Mizusawa-shi, Iwate Inside Hitachi Media Electronics Co., Ltd. (72) Inventor Kanji Kadota 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref. F-term in Hitachi Digital Media System Division (reference) 2F029 AA02 AB07 AC02 AC05 AC12 2F105 AA02 AA08 BB03 BB14 BB15 CC06 CD02 CD06 CD13 5H180 AA01 FF05 FF27 9A001 JZ78 KK37 KZ42

Claims (5)

[Claims] 1. An angular velocity detecting device for detecting a Coriolis force according to an angular velocity by a doubly supported vibrating beam, wherein said vibrating beam comprises: a first lithium tantalate piezoelectric body polarized in a thickness direction; A vibrating beam having a rectangular parallelepiped bimorph structure in which a second lithium tantalate piezoelectric material polarized in a direction opposite to the polarization direction of the vibrating beam is laminated, and the thickness t of the vibrating beam is the width of the vibrating beam. An angular velocity detection device characterized by being larger than W. 2. An angular velocity detecting device for detecting Coriolis force according to an angular velocity by a doubly supported vibrating beam, wherein the vibrating beam is a first lithium tantalate piezoelectric body polarized in a thickness direction; A vibrating beam having a rectangular parallelepiped bimorph structure in which a second lithium tantalate piezoelectric material polarized in a direction opposite to the polarization direction of the vibrating beam is laminated, and the thickness t of the vibrating beam is the width of the vibrating beam. W and the shape ratio W / t of the width W and the thickness t is 0.864.
An angular velocity detection device having a value of not less than 0.957 and not more than 0.957. 3. An angular velocity detecting device for detecting Coriolis force according to angular velocity by at least two doubly supported vibrating beams arranged so that their longitudinal directions are orthogonal to each other, and a camera shake based on an output of said angular velocity detecting device. A camera comprising: a vibration-proof unit that corrects the angular velocity, wherein the angular velocity detection device is the angular velocity detection device according to claim 1 or 2. 4. An angular velocity detecting device for detecting Coriolis force according to angular velocity by at least two doubly supported vibrating beams arranged so that their longitudinal directions are orthogonal to each other, and a vehicle based on an output of said angular velocity detecting device. 3. A car navigation system comprising: means for detecting a traveling direction of a vehicle, wherein the angular velocity detecting device is the angular velocity detecting device according to claim 1 or 2. 5. An angular velocity detecting device for detecting Coriolis force according to angular velocity by at least two doubly supported vibrating beams arranged so that their longitudinal directions are orthogonal to each other, and a vehicle based on an output of said angular velocity detecting device. An automobile comprising: means for controlling the attitude of the vehicle, wherein the angular velocity detection device is the angular velocity detection device according to claim 1 or 2.