JP2002022448A - Angular speed sensor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance detection accuracy of angular speed. SOLUTION: The angular speed sensor comprises a tuning fork oscillator 21 composed of piezoelectric ceramic having a base 22 on which protruding fixing parts 22a, 22b are formed, and an exciting shaft 23 and a detecting shaft 24 standing oppositely on the base 22. As the polarizing direction of the exciting shaft 23, plane normal polarization is performed such that exciting electrodes 25a, 25c and 25b, 25d on the surface and rear of the exciting shaft 23 have opposite polarization directions. As the polarizing direction of the detecting shaft 24, plane normal polarization is performed such that detection electrodes 26a, 26c and 26d, 26f on the opposite sides on the surface and rear of the detecting shaft 24 have opposite polarization directions. Furthermore, in-plane polarization is performed such that central detection electrodes 26b, 26e on the surface and rear of the detecting shaft 24 have a zero potential with respect to the detection electrodes 26a, 26c, 26d and 26f.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor and a method for manufacturing an angular velocity sensor, and more particularly, to an angular velocity sensor used for attitude control of a moving body such as a vehicle, an aircraft, a ship, and a navigation system, and a method for manufacturing the angular velocity sensor. .

[0002]

2. Description of the Related Art In recent years, as information has become more sophisticated, sensors capable of obtaining more accurate information have been demanded, and sensors have been developed in various fields. In particular, angular velocity sensors are among the most important of these sensors, and among them, the tuning fork vibration type has been applied in a wide field because it can be reduced in size and weight.

As a conventional tuning-fork type angular velocity sensor of this type, for example, the one shown in FIG. 34 is known. In FIG. 34, a base 1 is provided with a U-shaped metal diaphragm 3 via a fixed shaft 2, and is disposed above the metal diaphragm 3 in a direction perpendicular to the surface of the metal diaphragm 3. A pair of metal plates 4 and 5 are provided.

An excitation piezoelectric element 6 is provided on one surface of the metal vibration plate 3, and a monitoring piezoelectric element 7 is provided on the other surface, and these piezoelectric elements 6, 7 are provided.
Are fixed to the metal diaphragm 3 by an adhesive. Further, Coriolis detecting piezoelectric elements 8 and 9 are provided on the metal plates 4 and 5 so as to be orthogonal to the planes of the piezoelectric elements 6 and 7.
5 is fixed. And. The metal vibration plate 3, the metal plates 4 and 5, and the piezoelectric elements 6 to 9 constitute a tuning fork vibrator 20.

The piezoelectric elements 6 to 9 are connected to lead pins 14 to 17 by lead wires 10 to 13, respectively.
These lead pins 14 to 17 are electrically insulated from the base 1 via an insulator 18 such as glass.

Next, the operation of the angular velocity sensor will be described.

FIG. 34A is a diagram showing an excitation state of the angular velocity sensor, and FIG. 34B is a diagram showing a state of detecting the Coriolis force of the angular velocity sensor.

First, in FIG. 1A, when a voltage is applied to the excitation piezoelectric element 6, the tuning fork vibrator 20 is excited in the direction indicated by the arrow A. The excitation frequency and amplitude at this time are monitored by the monitoring piezoelectric element 7, so that the voltage applied to the excitation piezoelectric element 6 is controlled so that the tuning fork vibrator 20 is always excited at a constant frequency and amplitude. .

On the other hand, as shown in FIG. 34 (b), when a rotational angular velocity ω is applied to the detection shaft 18 of the sensor in the direction of arrow B, the metal plates 4, 5 are caused by Coriolis force generated in a direction perpendicular to the excitation direction A. It bends in opposite directions 19a and 19b.

The Coriolis force FC generated at this time is
Is FC = 2 mVω.

Here, m is the mass of the tuning fork vibrator, V is the excitation speed, and ω is the applied rotational angular velocity.

The Coriolis force FC extends in one direction of the Coriolis detecting piezoelectric elements 8 and 9 and generates a distortion in the other direction in which the Coriolis detecting piezoelectric elements 8 and 9 contract. Therefore, the detection voltages of the Coriolis detecting piezoelectric elements 8 and 9 are output as differential outputs. Since it can be taken out from the lead pins 13 and 15 via the lead wires 10 and 11, an angular velocity can be obtained from this differential output.

[0013]

However, in such a conventional angular velocity sensor, when a rotational angular velocity ω is generated, a Coriolis force is applied to the tuning fork vibrator 20 to cause the tuning fork vibrator 20 to move as shown in FIG. Since the rotational moment M generated by bending in the directions indicated by 19a and 19b is applied to the fixed shaft 2, the degree of fixation of the fixed shaft 2, the base 1, and the metal diaphragm 3 depends on the variation factor of the angular velocity detection accuracy of the sensor. As a result, there is a problem that the detection accuracy of the angular velocity cannot be improved.

Further, since the excitation piezoelectric element 6, the monitor piezoelectric element 7, and the Coriolis detection piezoelectric elements 8, 9 are fixed to the metal vibration plate 3 and the metal plates 4, 5 with an adhesive, the dispersion of the adhesion and the adhesion are reduced. In addition to the temperature characteristics of the agent causing variations in the detection accuracy of the angular velocity of the sensor, the adhesion accuracy, the bending accuracy of the tuning fork vibrator 20, the fixing accuracy of the fixed shaft 2, the tuning fork vibrator 20, and the base 1 and the like. The variation in the accuracy of the assembling process also caused the variation in the accuracy of detecting the angular velocity by the sensor.

Further, since the shapes (thickness and width) of the metal vibration plate 3 and the metal plates 4 and 5 do not match in the excitation direction and the Coriolis detection direction, the resonance frequency Fa at the time of excitation is different from that in FIG. It is difficult to match the resonance frequency Fb at the time of Coriolis detection, resulting in a non-resonant type angular velocity sensor, which has a problem that the sensitivity is reduced as compared with the resonance type.

The lead wires 10 to 13 are connected to the piezoelectric elements 6 to 9 respectively.
Are connected to the vibrating metal plate 3 and the vibrating plates 4 and 5 via the interface, the torsion of the lead wires 10 to 13 causes a variation in the detection accuracy of the angular velocity of the sensor.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide an angular velocity sensor and a method of manufacturing the angular velocity sensor which can enhance the accuracy of detecting the angular velocity.

[0018]

According to a first aspect of the present invention, there is provided an angular velocity sensor comprising: a base on which a protruding fixing portion is formed; a first excitation shaft standing upright from the base and opposed to the base; A tuning fork vibrator composed of a piezoelectric element having a shaft,
The tuning fork vibrator is excited in an in-plane direction where the first excitation axis and the first detection axis are close to and separated from each other, and an angular velocity having a rotation axis in the same direction as the central axis of the tuning fork vibrator is applied in the excited state. In the angular velocity sensor configured to detect a Coriolis force generated in a direction substantially perpendicular to the excitation direction as a deflection in a direction perpendicular to the surface of the tuning fork vibrator, the polarization direction of the first excitation axis is A plurality of pairs of opposing electrodes on the front and back surfaces of one excitation axis perform surface-perpendicular polarization so that the polarization directions are opposite to each other, and the polarization directions of the first detection axis are on both sides of the front and back surfaces of the first detection axis. In the counter electrode, the surface is polarized perpendicularly to the front and back surfaces,
The center counter electrode on the front and back surfaces of the first detection axis has a configuration in which in-plane polarization is performed between the counter electrodes on both sides so that the center counter electrode has zero potential.

With such a configuration, the tuning fork vibrator is excited in the in-plane direction, and in this excited state, an angular velocity is applied around the central axis of the tuning fork vibrator, so that the plane perpendicular to the excitation direction is generated. The angular velocity can be detected by detecting the Corioliska that occurs in the vertical direction as the deflection of the detection axis in the direction perpendicular to the plane of the detection axis.

In this configuration, since the tuning fork vibrator can be integrated with a unimorph, no adhesive is required as in the case of forming a bimorph tuning fork vibrator, and the vibration characteristics can be stabilized. In addition, the in-plane vibration characteristics can be stabilized by utilizing the characteristics of the tuning fork vibrator.

Further, since the excitation of the tuning fork vibrator is in-plane tuning fork excitation, the excitation efficiency can be improved, and a plurality of pairs (two electrodes) of the front and back surfaces are formed on the excitation shaft. Thus, the area of the excitation electrode for in-plane excitation can be increased, so that the excitation efficiency can be improved.

In addition, an electrode which becomes zero potential due to in-plane polarization is disposed at the center of the detection axis, and +
-By arranging the electrodes with the opposite potential, the detection output of Coriolis can be taken out by the differential between the electrodes on both sides and the electrode at the central zero potential, so that noise can be canceled and the detection sensitivity can be improved. Can be improved.

An angular velocity sensor according to a second aspect of the present invention is provided on a surface of the first excitation shaft and is led out to the base.
Two excitation electrodes, two excitation electrodes provided on the back surface of the first excitation shaft so as to face the two excitation electrodes and led to the base, and provided on the front surface of the first detection shaft. Three detection electrodes led to the base, three detection electrodes provided on the back surface of the first detection shaft so as to face the three detection electrodes, and led to the base; An arm-shaped fitting portion fitted to the ridge portion so as to sandwich the ridge portion of the fixed portion, and holding the tuning fork vibrator by fitting the fixed portion to the fitting portion. And a holding member.

With such a configuration, by leading both the excitation and detection electrodes to the base, the signal line connection with the circuit board can be performed on the base with little vibration, thereby improving the connection reliability. Can be achieved.

Also, a holding member for holding the tuning fork vibrator is provided, and the holding member is provided with an arm-shaped fitting portion fitted to the ridge so as to sandwich the ridge of the fixed portion in the form of a protrusion. When the tuning fork vibrator is held, the arm-shaped fitting portion is deformed to obtain a spring property, and the tuning fork vibrator can be stably held. The influence can be reduced.

An angular velocity sensor according to a third aspect of the invention has a configuration in which the tuning fork vibrator is mounted on a circuit board via the holding member.

With this configuration, the holding member can be easily mounted directly on the circuit board by soldering or the like, so that the mounting reliability of the tuning fork vibrator can be increased and the workability of the mounting operation can be improved. Can be improved.

The angular velocity sensor according to a fourth aspect of the invention has a configuration in which the tuning fork vibrator is mounted on a circuit board such that the rotation axis and the yaw rotation axis direction of the tuning fork vibrator are in the same direction.

With such a configuration, the angular velocity at the time of yaw rotation of an automobile or the like can be detected with high accuracy.

An angular velocity sensor according to a fifth aspect of the present invention is provided integrally with the tuning fork vibrator with a base of the tuning fork vibrator interposed therebetween,
A second detection axis opposed to the first excitation axis and having a polarization direction and an electrode under the same conditions as the first detection axis, and provided integrally with the tuning fork vibrator with the base of the tuning fork vibrator interposed therebetween; , The first detection axis and the first
A second excitation axis having a polarization direction and an electrode having the same conditions as the excitation axis; and the first excitation axis and the first detection when the first excitation axis and the second excitation axis are excited in the in-plane direction. The second excitation axis and the second detection axis are excited in directions opposite to the excitation direction of the axes, and when the Coriolis force is generated in a direction substantially orthogonal to the excitation direction, the first detection axis and the second detection axis Vibrates in the direction perpendicular to the surface in the opposite direction.

With such a configuration, the tuning fork vibrator has an H-shaped structure in which the excitation axis and the detection axis are alternately opposed to each other with the base interposed therebetween, so that the vibration leak due to the tuning fork vibration is reduced during in-plane excitation. be able to. In addition, when detecting the vertical direction of the plane, the vertical vibrations of the upper and lower two sets of tuning fork vibrators can be applied in the direction in which the moments cancel each other out. You can get a child. As a result,
The detection sensitivity can be improved, and the excitation is performed in the in-plane direction by opening and closing directions (proximity,
(Separation directions) are opposite to each other, and a stable fixing can be performed by reducing (cancelling) the moment at the fixing portion.

Further, the moment generated in the fixed portion can be caused to act in the direction of canceling by the upper and lower excitation axes and the detection axis by the surface vertical vibration at the time of detection of Corioliska, so that the stable fixation against Corioliska detection is achieved. Can do it. As a result, the efficiency of both excitation and detection can be improved, and the sensitivity can be improved.

In the angular velocity sensor according to a sixth aspect, the holding member is made of tungsten, phosphor bronze, or stainless steel.

With such a configuration, as the holding member,
Uses tungsten, phosphor bronze, or stainless steel with high specific gravity and high spring properties to reduce vibration leakage during excitation of the tuning fork vibrator and detection of Coriolis force, and holds the tuning fork vibrator stably with the holding member can do.

A method of manufacturing an angular velocity sensor according to a seventh aspect of the present invention is the method of manufacturing an angular velocity sensor according to any one of the first to sixth aspects of the present invention. After preparing the excitation electrode and the detection electrode collectively by photolithography on the sheet material, and then applying a voltage to the excitation electrode and the detection electrode to collectively perform the polarization process in the polarization direction, The tuning fork vibrator is cut out from the sheet material.

In such a manufacturing method, the tuning fork vibrator, which is the heart of the acceleration sensor, is formed by collective electrode formation, collective polarization processing,
It can be manufactured by the consolidation cutout method, and the cost of the acceleration sensor can be reduced.

In the method for manufacturing an angular velocity sensor according to an eighth aspect of the present invention, the holding member plated is prepared.
After fitting the fixing portion of the tuning fork vibrator cut out of the sheet material into the fitting groove of the holding member, the holding member is heated to fill the gap between the fixing portion and the fitting groove with the plating. I am trying to do it.

According to such a manufacturing method, the holding member can be brought into close contact with the fixing portion, and the tuning fork vibrator can be stably and reliably attached to the holding member.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is an explanation based on an embodiment of the present invention.

FIGS. 1 to 16 are views showing a first embodiment of an angular velocity sensor and a method of manufacturing the angular velocity sensor according to the present invention. The angular velocity sensor according to the present embodiment controls the attitude of a moving body such as a vehicle, an aircraft or a ship. And navigation systems.

First, the configuration will be described. 1 and 2, a tuning fork vibrator 21 includes a base 22 on which protruding fixing portions 22a and 22b are formed, an excitation shaft (first excitation shaft) 23 standing upright from the base 22, and opposed to each other. A detection axis (first detection axis) 24 is provided, and is made of piezoelectric ceramics.

Further, two excitation electrodes are provided on the surface of the excitation shaft 23.
25a and 25b are provided, and two excitation electrodes 25c and 25d are provided on the back surface of the excitation electrode 23 so as to face the excitation electrodes 25a and 25b.
d is led out to the base 22.

Also, three detection electrodes 26 are provided on the surface of the detection shaft 24.
a to 26c and three detection electrodes 26 on the back surface of the detection shaft 24 so as to face the detection electrodes 26a to 26c.
d to 26f are provided, and these detection electrodes 26a to 26f
Is led out to the base 22.

Further, the excitation electrodes 25a and 25d and the excitation electrodes
Plane-perpendicular polarization is performed on 25b and 25c so that the polarization directions are opposite to the directions indicated by arrows 27a and 27b. The detection electrodes 26a and 26f on both sides and the detection electrodes 26c and 26d
Is perpendicularly polarized so that the polarization direction is opposite to the direction indicated by arrows 28a and 28b, and the central detection electrode 26b and the electrodes 26a and 26c on both sides are in-plane polarized in the directions of arrows 29a and 29b. And the center detection electrode 26e and both side electrodes 26
d and 26f are in-plane polarized in the directions of arrows 29c and 29d opposite to the directions of arrows 29a and 29b.

For this reason, the positive potential after polarization is
a and 25c and the detection electrodes 26a and 26d, the negative electrodes become the excitation electrodes 25b and 25d and the detection electrodes 26f and 26c, and the central detection electrodes 26b and 26e become the zero electrodes and become the base 22.
Is derived.

The excitation electrodes 25a and 25b formed on the surface of the excitation shaft 23 are connected by wires 30a, and the electrodes 25c and 25d formed on the back surface of the excitation shaft 23 are connected to the wires 30b.
Connected by

Further, independent electrodes 31a to 31d are formed on the front and back surfaces of the fixing portions 22a and 22b, respectively, and these independent electrodes 31a to 31d come into contact with a clamper block (holding member) 32 shown in FIGS. It has become.

The clamper block 32 is made of tungsten,
It is made of phosphor bronze, stainless steel, or the like, and holds the tuning fork vibrator 21 so as to sandwich the fixing portions 22a and 22b.

That is, the clamper block 32 is fixed by a main body 33 on which guide pins 33a to 33d are formed, and V-grooves 34a, 35a provided on the main body 33 and formed at the distal end.
The fixing portions 22a, 22b hold the ridges ad of the 22a, 22b.
Arm members (fitting portions) 34 and 35 fitted to 22b are provided, and the main body 33 and arm members 34 and 35 are separated by three sleeves 36a and 36b to form the arm members 34 and 35 in the main body 33. Have been. In addition, the tip of the arm members 34 and 35 has V
A semicircular groove may be formed instead of the groove.

The clamper block 32 obtains a spring property by holding the tuning fork vibrator 21 by the arm members 34 and 35 and deforming the arm members 34 and 35 so that the areas of the slits 36a and 36b are widened. Can be.

The V-grooves 34a, 35 of the clamper block 32
As shown in FIG. 4A, low melting point plating 37 is previously applied to a. After the clamper block 32 is attached to the tuning fork vibrator 21, the V-grooves 34a and 35a are shown in FIG. As shown in the drawing, the low melting point plating 37 is heated by the heater block 38 to reflow, so that the V-grooves 34a, 35a of the ridges a to d of the fixed portions 22a, 22b generated by the processing accuracy of the tuning fork vibrator 21.
Are filled with low melting point plating 37 via the independent electrodes 31a to 31d to reduce the variation in fixing the tuning fork vibrator 21 and the clamper block 32. In addition, the tuning fork vibrator 21
Alternatively, the independent electrodes 31a to 31d may be grounded via the clamper block 32 to which the low melting point plating 37 is applied.

Here, the operation mechanism of the tuning fork vibrator 21 will be described with reference to FIG.

The fixed part 22a,
In the tuning fork vibrator 21 having the fixed 22b, the excitation shaft 23 and the detection shaft 24 are excited in in-plane directions 39a, 39b and 39c, 39d as shown in FIG. You.

Specifically, when the excitation shaft 23 oscillates in the direction of arrow 39a, the detection shaft 24 oscillates in the direction of arrow 39c due to the tuning fork effect, and at the next moment, the excitation shaft 23 and the detection shaft 24 move in the direction of arrow 39a.
Vibration occurs in the directions of arrows 39b and 39d opposite to directions a and 39c, and this operation, that is, the in-plane vibration where the excitation shaft 23 and the detection shaft 24 approach and separate from each other is repeated.

In such an in-plane excitation state, when a rotational angular velocity Ω about the center axis 40 of the vibrator 21 is applied to the tuning fork vibrator 21, Coriolis force is generated in a direction substantially orthogonal to the excitation direction. As a result, the excitation shaft 23 and the detection shaft 24 generate vibrations in components perpendicular to the plane 40a and 40b as shown in FIGS. Then, this vibration component is
The magnitude of the applied angular velocity is measured by detecting with the detection electrodes 26a to 26f formed on the 24.

FIG. 6 is a diagram showing a circuit configuration for detecting excitation and angular velocity.

In FIG. 6, the excitation electrodes 25a and 25b formed on the surface of the excitation shaft 23 are connected to one terminal (COMO) of a power source 42.
The excitation electrodes 25c and 25d connected to the N-line) 42a and formed on the back surface are connected to the other terminal (DRV
Line) 42b, and by applying positive and negative voltages alternately from the power source 42 to the excitation electrodes 25a to 25d, the right part of the excitation shaft 23 surrounded by the reference numeral 43a and the left part surrounded by the reference numeral 43b alternately extend. The contraction is repeated, and the excitation shaft 23 vibrates in the in-plane direction X.

At this time, the detection axis is set by the tuning fork effect.
24 vibrates in the in-plane direction X by the mechanism described above.

The electrodes 26a to 26c formed on the detection shaft 24 vibrate in the direction perpendicular to the plane Y generated by the generation of the Coriolis force.
Detection axis by alternate expansion and contraction with the lower part surrounded by 44b
The voltage generated in 24, the electrode 26b as the ground electrode, the detection electrode 26a taken from the differential amplifier 45, the differential output of 26c ^- output terminal 46 as the (S and the differential between the S ⁺ line output)
a and 46b can be taken out. FIG.
Medium, + and-indicate a high potential and a low potential, respectively.

Next, the configuration of the angular velocity sensor to which the tuning fork vibrator 21 is mounted will be described with reference to FIGS.

FIG. 7 is a view showing a vibrator unit. In FIG. 7, the clamper block 32 and the tuning fork vibrator 21
The vibrator unit 47 is formed by integrating electronic components 48a,
48b is attached to a substrate 48 provided integrally.
Specifically, guide pins 33a, 33b formed on the main body 33
Is inserted into an insertion hole formed in the substrate 48 and soldered, so that the vibrator unit 47 is fixed to the substrate 48 via the clamper block 32. The substrate 48 includes the circuit described with reference to FIG.

As shown in FIG. 8, an excitation electrode 25d formed on the back surface of the excitation shaft 23 and a COMMON pattern (not shown) described on the circuit of FIG.
49a.

FIG. 9 is a diagram for explaining the connection between each electrode and the circuit described in FIG.

In FIG. 9, formed on the surface of the excitation shaft 23
Excitation electrode 25a formed on the substrate 48
The turns are connected by wires 49b. In addition, inspection
First detection (not shown) formed on the output electrode 26c and the substrate 48
Pattern (S of differential amplifier 45 ^-Side) by wire 49c
Connected.

The center detection electrode 26b and the second detection pattern (not shown) formed on the substrate 48 are connected by a wire 49d. The detection electrode 26a is connected to a third detection pattern (not shown) (not shown) formed on the substrate 48.
(S ⁺ side) is connected by a wire 49e.

On the other hand, the vibrator unit 47 mounted on the substrate 48 shown in FIG. 9 includes electronic components 50a, 50b as shown in FIG.
Are mounted and connected to the substrate 50 mounted on the supporter 51. More specifically, the vibrator unit 47 and the board 48 are inserted into the through holes (not shown) formed in the board 50 and soldered by the guide pins 33c and 33d of the clamper block 32, so that the Mounted on The substrate 48 and the substrate 50 are connected by a flexible substrate 52a,
52a is fixed to the bottom 52 of the supporter 51 by an adhesive or the like.

As shown in FIGS. 11 and 12, the supporter 51 has lead pins 54a to 54c hermetically fixed by sealing glasses 53a to 53c and brazing (indicated by reference numeral 53d).
A bottom portion 52 is attached to a stem 55 having a lead pin 54d hermetically joined by the above method.

A cap 56 is attached to the stem 55 as shown in FIGS. The bottom surface of the cap 56 is attached to the stem 55 by vacuum suction, and the entire bottom surface 56a of the cap 56 is linked to the stem 55 by link projection welding or cold pressing.
It is fixed at 55. Thus, the angular velocity sensor 58 is obtained.

In FIG. 13, reference numeral 57 denotes a glass ball for insulating and floating from the substrate when the angular velocity sensor 58 is mounted on a substrate (not shown).

When the angular velocity sensor 58 is mounted on an automobile or the like, as shown in FIG.
By installing the tuning fork vibrator 21 on the acceleration sensor 58 so that the upper direction 59a is the top and the lower direction 59b is the ground, the yaw rotation of the car acts with the center axis 59 of the tuning fork vibrator 21 as the rotation axis. To do.

FIGS. 15 and 16 are views for explaining a method of manufacturing the tuning fork vibrator 21. FIGS.

First, as shown in FIG. 15A, a piezoelectric ceramic sheet material 60 which is fired into a sheet and finished to a predetermined thickness is prepared. Then, after forming electrodes on the entire surface of the sheet material 60 by electroless Ni plating or gold sputtering as shown in FIG. 2B, the end faces 60a to 60d of the sheet material 60 are formed as shown in FIG. And the electrodes are removed from the end faces 60a to 60d to finish the end faces 60a and 60b serving as the reference surfaces for the processing.

Next, as shown in FIG.
By performing photolithography processing on the front and back electrodes 60, detection electrodes including excitation electrodes and zero potential electrodes are collectively formed.

Next, as shown in FIG. 16 (a), the polarization 27a, 27b, 28a, 28b, 29a in each direction shown in FIG.
Perform ~ 29d.

Next, as shown in FIG.
After dividing the strip 60 into strip sheets 62a and 62b, a strip sheet 63 having a shape of the tuning fork vibrator 21 is cut from each strip sheet 62a and 62b as shown in FIG. From the sheet 63, as shown in FIG.
21 is divided into pieces.

As described above, in the present embodiment, the base 22 on which the protruding fixing portions 22a and 22b are formed, and the base 22
Excitation shaft 23 and detection shaft 24, which are erected from
Tuning fork vibrator 21 composed of piezoelectric ceramic having
And arm members 34 and 35 formed with V-grooves 34a and 35a fitted to the ridges a to d so as to sandwich the ridges a to d of the fixing portions 22a and 22b. Fixed parts 22a, 22 on 35a
b, and a clamper block 32 for holding the tuning fork vibrator 21 by fitting the same.
25a to 25d, detection electrodes 26a to 26f are provided on the front and back surfaces of the detection shaft 24, and excitation electrodes 25a and 25d on the front and back surfaces of the excitation shaft 23 are used as polarization directions of the excitation shaft 23.
The surface perpendicular polarization is performed so that the polarization directions are opposite to each other at 25b and 25c.
The detection electrodes 26a, 26c, 26d, and 26f on both sides of the front and back of the surface 24 perform reverse surface vertical polarization on the back surface, and the detection electrodes 26a and 26e on both sides of the center detection electrodes 26b and 26e on the front and back of the detection shaft 24. , 26c, 26d, 26f
Because 26b and 26e were subjected to in-plane polarization such that they became zero potential,
The tuning fork vibrator 21 is excited in the in-plane direction, and in this excited state, a Corioliska that is generated in a plane perpendicular direction to the excitation direction by applying an angular velocity about the central axis of the tuning fork vibrator 21 is generated. The angular velocity can be detected by detecting the deflection as a deflection in the direction perpendicular to the surface of the detection axis.

Further, since the tuning fork vibrator 21 can be formed into a unimorph integral structure, no adhesive is required as in the case of forming a bimorph tuning fork vibrator, and the vibration characteristics can be stabilized. In addition, the characteristics of the tuning fork type vibrator 21 can be utilized to stabilize the in-plane vibration characteristics.

Further, when the clamper block 32 holding the tuning fork vibrator 21 holds the tuning fork vibrator 21,
The spring properties can be obtained by deforming the elements 4 and 35, the tuning fork vibrator 21 can be stably held, and the variation in fixing can be reduced from affecting the detection sensitivity.

Further, since the excitation of the tuning fork vibrator 21 is an in-plane tuning fork excitation, the excitation efficiency can be improved, and the excitation shaft 23 can be formed by forming two electrodes on the front and back surfaces. Since the area of the excitation electrode for internal excitation can be increased, the excitation efficiency can be improved.

Further, on the detection axis 24, detection electrodes 26b and 26e having zero potential due to in-plane polarization are disposed at the center, and the detection electrodes 26a having positive and negative potentials on both sides due to surface perpendicular polarization.
By arranging 26c, 26d, and 26f, the detection output of Coriolis can be taken out by the differential between the electrodes on both sides and the electrode at the center zero potential, so that noise can be canceled and the detection sensitivity can be improved. .

Further, excitation and detection electrodes 25a to 25d, 26
By leading a to 26f to the base 22, the signal line connection with the circuit board 48 can be performed on the base 22 with less vibration, so that the connection reliability can be improved.

The tuning fork vibrator 21 is connected to a clamper block 32.
Mounted on the circuit board 48 via the
32 can be easily mounted directly on the circuit board 48 by soldering or the like, so that the reliability of the mounting of the tuning fork vibrator 21 can be increased and the workability of the mounting operation can be improved.

The center axis (rotation axis) 59 of the tuning fork vibrator 21
Tuning fork vibrator 21 so that the
Is mounted on the circuit board 48, so that the angular velocity during yaw rotation of an automobile or the like can be detected with high accuracy.

Further, by using tungsten, phosphor bronze or stainless steel having a large specific gravity and a high spring property as the clamper block 32, vibration leakage at the time of excitation of the tuning fork vibrator 21 and detection of Coriolis force can be reduced. The tuning fork vibrator 21 can be stably held by the clamper block 32.

In manufacturing the tuning fork vibrator 21,
A piezoelectric ceramic sheet material 60 is prepared, and the sheet material 60 is prepared.
Excitation electrode 25a collectively by photolithography
To 25d and the detection electrodes 26a to 26f are formed, and then a voltage is applied to the excitation electrodes 25a to 25d and the detection electrodes 26a to 26f to collectively perform polarization processing in the polarization direction as shown in FIG. Since the tuning fork vibrator 21 is cut out from the sheet material 60, the tuning fork vibrator 21, which is the heart of the acceleration sensor 58, can be manufactured by the collective electrode formation, collective polarization processing, and the collective cutout method. Cost can be reduced.

Further, a clamper block 32 which has been subjected to a low melting point plating 37 is prepared, and the fixing portions 22a, 22b of the tuning fork vibrator 21 cut from the sheet material 60 are fixed to the V-grooves 34a, 35a of the clamper block 32. After that, the clamper block 32 is heated by the heater block 38 to fill the gap between the fixing portions 22a, 22b and the V-grooves 34a, 35a with the low melting point plating 37. Tuning fork vibrator that can be in close contact with 22a and 22b
21 can be stably and reliably attached to the clamper block 32.

FIGS. 17 to 33 are views showing a second embodiment of the angular velocity sensor and the method for manufacturing the angular velocity sensor according to the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals. And the description is omitted.

In FIGS. 17 and 18, a tuning fork vibrator 71 includes a base 72 on which protruding fixing portions 72a and 72b are formed, a first excitation shaft 73 standing upright from the base 72 and facing the second base. It has a second excitation shaft 74, a first detection shaft 75, and a second detection shaft 76, and is made of piezoelectric ceramics. Also, the first excitation shaft 73, the second
The excitation shaft 74, the first detection shaft 75, and the second detection shaft 76 are provided so as to intersect with the base 72 interposed therebetween. That is, the tuning fork vibrator 71 includes two pairs of tuning fork vibrators 71a and 71b with the base 72 interposed therebetween.
Are facing each other.

Also, two excitation electrodes 77a and 77b are provided on the surface of the first excitation shaft 73, and the second excitation shaft 74
Are provided with two excitation electrodes 78a and 78b, and these electrodes 77a, 77b, 78a and 78b are led out to the base 72.

The excitation electrode 77 is provided on the back surface of the first excitation shaft 73.
The two excitation electrodes 79a and 79b are provided so as to oppose the excitation electrodes 78a and 78b, and the two excitation electrodes 80a and 80b are arranged on the back surface of the second excitation shaft 74 so as to oppose the excitation electrodes 78a and 78b.
80b are provided. These electrodes 79a, 79b, 80
a and 80b are led out to the base 72.

Also, three detection electrodes 81a to 81c are provided on the surface of the first detection shaft 75, and the second detection shaft 76
Are provided with three detection electrodes 82a to 82c, and these detection electrodes 81a to 81c and 82a to 82c are
It is derived and linked to 72.

The detection electrode 81a is provided on the back surface of the first detection shaft 75.
The detection electrodes 83a to 83c are provided so as to face the detection electrodes 82a to 82c.
The three detection electrodes 84a to 84c are provided so as to be opposed to .about.82c, and these detection electrodes 83a to 83c and 84a to 84c are led out to the base 72 and connected thereto.

Also, the excitation electrodes 77a and 77b formed on the front surface of the first excitation shaft 73 and the excitation electrodes 79a and 79 formed on the back surface.
b indicates that the surface is perpendicularly polarized so that the polarization directions are opposite to the directions indicated by arrows 85a and 85b, and the excitation electrodes 78a and 78b formed on the front surface of the second excitation shaft 74 and the excitation electrode formed on the back surface. The plane perpendicular polarization is performed such that the polarization directions of 80a and 80b are opposite to the directions indicated by arrows 86a and 86b.

The detection electrodes 81a, 81c on both sides of the front surface of the first detection shaft 75 and the detection electrodes 83a, 83a formed on both sides of the back surface.
83c is perpendicularly polarized in the opposite direction as indicated by arrows 87a and 87b. The center detection electrode 81b on the surface of the first detection axis 75 and the detection electrodes 81a and 81c on both sides are in the first direction indicated by 88a and 88b.
The detection electrode 83b at the center on the back of the detection shaft 75 and the detection electrodes on both sides
83a and 83c are in-plane polarized in directions indicated by 89a and 89b, respectively.

The detection electrodes 82a, 82c on both sides of the front surface of the second detection shaft 76 and the detection electrodes 84a,
84c is perpendicularly polarized in the opposite direction indicated by arrows 90a and 90b, and the center detection electrode 82b on the surface of the second detection shaft 76 and the detection electrodes 82a and 82c on both sides are in the second direction indicated by 91a and 91b.
The center detection electrode 84b on the back of the detection shaft 76 and the detection electrodes on both sides
84a and 84c are in-plane polarized in directions indicated by 92a and 92b, respectively.

For this reason, the positive potential after the polarization is
a, 79b, 78b, 80a and detection electrodes 81c, 83a, 82
a, 84c and the negative electrodes are the excitation electrodes 79a, 77b,
78a, 80b and detection electrodes 81a, 83c, 82c, 84a are provided, and the central detection electrodes 81b, 83b and 82b, 84b are zero electrodes and are led out to the base 72.

The excitation electrodes 77a, 77b, 78a, 78b formed on the surfaces of the first excitation shaft 73 and the second excitation shaft 74 are connected by wires 93a, 93b, 93c. Excitation electrode formed on the back of second excitation shaft 74
79a, 79b, 80a, 80b are connected by wires 93d, 93e, 93f.

The detection electrodes 81a to 81c and 82a to 82c formed on the front surfaces of the first detection shafts 75 and 76 are connected by a base 72, and are formed on the back surfaces of the first and second detection shafts 75 and 76. The detected electrodes 83a to 83c and 84a to 84c are connected by a base 72.

Further, independent electrodes 94a to 94d are formed on the front and back surfaces of the fixing portions 72a and 72b, respectively. These independent electrodes 94a to 94d have the same configuration as that of the first embodiment as shown in FIGS. The clamper block 32 having the shape shown in FIG.
As shown in FIG. 7, a low melting point plating 37 is applied. After the clamper block 32 is attached to the tuning fork vibrator 71, the V groove 34
The heater blocks a and 35a are as shown in FIG.
By heating at 38 and reflowing the low melting point plating 37, the fixed portion 72 generated by the processing accuracy of the tuning fork vibrator 71 is formed.
The gap between the ridges a to d of the a and 72b and the V-grooves 34a and 35a is filled with the low melting point plating 37 via the independent electrodes 94a to 94d so as to reduce the variation in fixing the tuning fork vibrator 71 and the clamper block 32. ing.

Here, the operation mechanism of the tuning fork vibrator 71 will be described with reference to FIG.

The clamper block 32 fixes the fixed portion 72a,
The tuning fork vibrator 71 to which 72b is fixed includes first and second excitation shafts 73,
The first and second excitation shafts 73 and 74 and the first and second detection shafts 75 and 76 are excited in in-plane directions 96a to 96d and 97a to 97b as shown in FIG. .

Specifically, when the first excitation shaft 73 vibrates in the direction of the arrow 96b, the first detection shaft 75 is moved by the arrow 96b due to the tuning fork effect.
When the second excitation shaft 74 oscillates in the direction of arrow a and the second excitation shaft 74 similarly oscillates in the direction of arrow 97a, the second detection shaft 76 moves in the direction of arrow 97b by the tuning fork effect.
At the next moment, the first excitation shaft 73 and the first detection shaft 75 oscillate in the directions of arrows 96c and 96d opposite to the arrows 96a and 96b, and similarly the second excitation shaft 74 and the second detection shaft 76 vibrates in the direction of the arrows 97d and 97c opposite to the directions of the arrows 97b and 97a,
This operation, that is, the first excitation shaft 73 and the first detection shaft 75
And the second excitation shaft 74 and the second detection shaft 76 repeat the in-plane vibration approaching and separating from each other.

In such an in-plane excitation state, when a rotational angular velocity Ω about the center axis 98 of the vibrator 71 is applied to the tuning fork vibrator 71, Coriolis force is generated in a direction substantially orthogonal to the excitation direction. Therefore, the first and second excitation axes 73 and 74 and the first and second detection axes 75 and 76 generate vibrations of components in the direction perpendicular to the plane 99a to 99d as shown in FIGS. Then, the vibration components are detected by the detection electrodes 81a to 81c, 82a to 82c, 83a to 83c, 84a to 81a formed on the first and second detection shafts 75 and 76.
By detecting at 84c, the magnitude of the applied angular velocity is measured.

FIG. 22 is a diagram showing a circuit configuration for detecting excitation and angular velocity.

In FIG. 22, excitation electrodes 77a, 77b, 78a, 78b formed on the surfaces of the first and second excitation shafts 73, 74 are provided with power sources.
Excitation electrodes 79a, 79b, 80 which are connected to one terminal (DRV line) 100a of
a and 80b are the other terminals (COMMON line) 1 of the power supply 100
The first and second excitation shafts 73 and 74 are surrounded by reference numerals 101a and 102a, and are denoted by reference numeral 101 by alternately applying positive and negative voltages from the power supply 100 to the excitation electrodes 77a and the like.
b, the right part surrounded by 102b alternately expands and contracts repeatedly,
The first and second excitation shafts 73 and 74 vibrate in the in-plane direction X.

At this time, the first, due to the tuning fork effect,
2 The detection shafts 75 and 76 vibrate in the in-plane direction X by the mechanism described above.

The detection electrodes 81a and 82c, the detection electrodes 81b and 82b, and the detection electrodes 81c and 82a
Are connected to each other, and the detection electrode 83a and the detection electrode 84
c, the detection electrode 83b and the detection electrode 84b are connected, and the detection electrode 83c and the detection electrode 84a are connected. The detection electrode 81a and the detection electrode 82c are connected to one pole of the differential amplifier 103, and the detection electrode 81c and the detection electrode 82a are connected to the differential amplifier 103.
Is connected to the other pole.

Therefore, the first detection axis 75 and the second detection axis
When 76 vibrates in the direction perpendicular to the plane due to the Coriolis force, the upper portion surrounded by reference numerals 104a and 105a and the upper portions 104b and 105
1st, 2nd by the alternate expansion and contraction with the lower part surrounded by b
The voltage generated on the detection axes 75 and 76 is applied to the detection electrodes 81b, 82b and 83
b, and 84b as the ground electrode, the differential amplifier 103 detecting electrode 81a taken from, 81c, 82a, the differential output of 82c ^- output terminal 106 as the (S and the differential between the S ⁺ line output)
a, 106b. Fig. 2
2, + and-indicate a high potential and a low potential, respectively.

Next, the configuration of the angular velocity sensor to which the tuning fork vibrator 21 is attached will be described with reference to FIGS.

First, FIG. 23 is a diagram showing a vibrator unit. In FIG. 23, the clamper block 32 and the tuning fork vibrator 71
The vibrator unit 107 formed by integrating the electronic components 108a
To 108d are attached to a substrate 108 provided integrally therewith.

More specifically, the guide pins 33a and 33b formed in the main body 33 are inserted into the insertion holes formed in the board 108 and soldered, so that the vibrator unit 107 is connected to the board via the clamper block 32. Fixed to 108. Note that the substrate 108 includes the circuit described in FIG.

As shown in FIG. 24, the excitation electrode 80b formed on the back surface of the first excitation shaft 73 is connected to the COMMON pattern (not shown) formed on the substrate 108 by the wire 109a. ing.

FIG. 25 is a diagram for explaining the connection between each electrode and the circuit described in FIG.

In FIG. 25, an excitation electrode 77b formed on the surface of the first excitation shaft 73 is connected to an excitation pattern (not shown) formed on the substrate 108 by a wire 109b.
In addition, a first detection pattern (not shown) formed on the detection electrode 81a of the first detection axis 75 and the substrate 108 (not shown).
^- side) are connected by wire 109c.

Further, the detection electrode 81c of the first detection axis 75 and the substrate
A second detection pattern (not shown) formed on 108 (S ⁺ side of differential amplifier 103) is connected by wire 109d. The detection electrode 81b of the first detection axis 75 is connected to a third detection pattern (not shown) formed on the substrate 108 by a wire 109.
e.

On the other hand, as shown in FIGS. 26 and 27, the vibrator unit 107 mounted on the substrate 108 shown in FIG.
a to 110 e are mounted and connected to the substrate 112 mounted on the supporter 111.

More specifically, the vibrator unit 107 and the substrate 108 are connected via the supporter 111 by inserting the guide pins 33c and 33d of the clamper block 32 into insertion holes (not shown) formed in the substrate 112 and soldering the same. And is attached to the substrate 112. The substrate 108 and the substrate 112 are connected by a flexible substrate 113a, and the flexible substrate 113a is fixed to the bottom 113 of the supporter 111 by an adhesive or the like.

As shown in FIGS. 28 and 29, the supporter 111 is connected to lead pins 115a to 115c hermetically fixed by sealing glasses 114a to 114c and brazing (reference numeral 114d).
The bottom 113 is attached to a stem 116 having a lead pin 115d that is hermetically joined by the above-described method.

A cap 117 is attached to the stem 116 as shown in FIGS. This cap 117 is fixed to the stem 116 by vacuum suctioning the cap 117 with the bottom surface attached to the stem 116 and link-projection welding or cold pressing the entire periphery of the bottom surface 117a of the cap 117 to the stem 116. Has become. Thus, the angular velocity sensor 118 is obtained.

In FIG. 30, reference numeral 119 denotes an angular velocity sensor 118.
Is a glass ball that is insulated from the substrate and floats when mounted on a substrate (not shown).

When the angular velocity sensor 119 is mounted on an automobile or the like, as shown in FIG. 30, the acceleration is set so that the upward direction 120a of the central axis 120 of the tuning fork vibrator 71 is the top and the downward direction 120b is the ground. By installing the tuning fork vibrator 71 on the sensor 118, the yaw rotation of the vehicle acts on the center axis 120 of the tuning fork vibrator 71 as a rotation axis.

FIGS. 32 and 33 are views for explaining a method of manufacturing the tuning fork vibrator 21. FIGS.

As shown in FIG. 32A, a piezoelectric ceramic sheet material 121 which is fired into a sheet and finished to a predetermined thickness is prepared. Next, as shown in FIG. 3B, electrodes are formed on the entire surface of the sheet material 121 by electroless Ni plating or gold sputtering or the like, and then the end faces 121a to 121d of the sheet material 121 are formed as shown in FIG. And the electrodes are removed from the end faces 121a to 121d to finish the end faces 121a and 121b serving as reference faces for the processing.

Next, as shown in FIG.
By subjecting the front and back electrodes 121 to photolithography processing, detection electrodes including excitation electrodes and zero potential electrodes are collectively formed.

Next, as shown in FIG. 33 (a), the plane perpendicular polarization 122a and the in-plane polarization 122b are collectively performed,
Polarization 85a, 85b, 86a, 86b, 87 in each direction shown in FIG.
a, 87b, 88a, 88b, 89a, 89b, 90a, 90b, 91a
To 91d and 92a to 92d.

Next, as shown in FIG.
After the 121 is divided into strip sheets 123a and 123b, a strip sheet 124 having a shape of the tuning fork vibrator 71 is cut from each of the strip sheets 123a and 123b as shown in FIGS. The tuning fork vibrator 71 is divided into individual pieces from the strip sheet 124 as shown in FIG.

As described above, in this embodiment, the first excitation shaft 73 and the second detection shaft 76 are opposed to each other with the base 22 interposed therebetween, and the second excitation shaft 74 and the first detection shaft 75 are opposed to each other. When the shaft 73 and the second excitation shaft 74 are excited in the in-plane direction, the first excitation shaft
73 and the excitation direction of the first detection shaft 75, the second excitation shaft 74 and the second
The detection shaft 76 is excited in the opposite direction, and when Coriolis force is generated in a direction substantially perpendicular to the excitation direction, the first detection shaft 75 and the second detection shaft 76 oscillate in opposite directions perpendicular to the plane. In other words, the excitation shaft with the tuning fork vibrator 71
Due to the H-shaped structure in which the detection shafts 73 and 74 and the detection shafts 75 and 76 are alternately opposed, vibration leakage due to tuning fork vibration can be reduced during in-plane excitation.

In addition, when detecting the vertical direction of the surface, the vertical vibrations of the upper and lower two sets of tuning fork vibrators 71a and 71b can be applied in the direction in which the moments cancel each other. The tuning fork vibrator 71 with less vibration leakage can be obtained. As a result, the detection sensitivity can be improved, and the excitation can be performed in the in-plane direction such that the opening and closing directions (proximity and separation directions) of the two sets of the excitation shafts 73 and 74 and the detection shafts 75 and 76 are opposite to each other. The moment at the fixing portions 72a and 72b can be reduced (canceled) and stable fixing can be performed.

Further, the moment generated in the fixed portions 72a and 72b by the surface vertical vibration at the time of detection of the Coriolis can be caused to act in the direction in which the upper and lower excitation shafts 73 and 74 and the detection shafts 75 and 76 cancel each other. Stable fixing can be performed for detection. As a result, the efficiency of both excitation and detection can be improved, and the sensitivity can be improved.

The effects of the same configuration and manufacturing method as in the first embodiment are the same as those in the first embodiment, and a description thereof will not be repeated.

[0131]

According to the present invention, the tuning fork vibrator can be formed into a unimorph integral structure, so that an adhesive is unnecessary as in the case of forming a bimorph tuning fork vibrator, and the vibration characteristics can be stabilized. In addition, the in-plane vibration characteristics can be stabilized by utilizing the characteristics of the tuning fork vibrator.

Also, since the excitation of the tuning fork vibrator is in-plane tuning fork excitation, the excitation efficiency can be improved and a plurality of pairs (two electrodes) of the front and back surfaces are formed on the excitation shaft. Thus, the area of the excitation electrode for in-plane excitation can be increased, so that the excitation efficiency can be improved.

Further, an electrode which becomes zero potential due to in-plane polarization is arranged at the center of the detection axis, and +
-By arranging the electrodes with the opposite potential, the detection output of Coriolis can be taken out by the differential between the electrodes on both sides and the electrode at the central zero potential, so that noise can be canceled and the detection sensitivity can be improved. Can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of an angular velocity sensor and a method for manufacturing the angular velocity sensor according to the present invention, wherein (a) is a front view of the tuning fork vibrator, and (b) is a polarization direction of the tuning fork vibrator. FIG. 4 is a bottom view of an excitation axis and a detection axis, showing the above.

FIG. 2A is a side view of the tuning fork vibrator of the first embodiment,
(B) is a rear view of the tuning fork vibrator of the first embodiment.

3A is a front view showing a state where the tuning fork vibrator of the first embodiment is held by a clamper block, FIG. 3B is a side view thereof, and FIG. 3C is a bottom view thereof.

FIG. 4A is a partial detailed view of a clamper unit according to the first embodiment, and FIG. 4B is a diagram illustrating a state in which the clamper unit is heated by a heater.

5A is a diagram illustrating an excitation state of the tuning fork vibrator according to the first embodiment, FIG. 5B is a side view illustrating a vibration state of the tuning fork vibrator when Coriolis force is generated, and FIG. It is a perspective view of the tuning fork vibrator in the state of (b).

FIG. 6 is a diagram illustrating an angular velocity detection circuit of the tuning fork vibrator according to the first embodiment.

7A is a front view showing a state where the tuning fork vibrator unit of the first embodiment is mounted on a substrate, FIG. 7B is a side view thereof, and FIG. 7C is a bottom view thereof.

FIG. 8A is a front view showing a state where the back surface of the tuning fork vibrator unit of the first embodiment is wire-bonded to a substrate, and FIG. 8B is a bottom view thereof.

9A is a front view showing a state where the surface of the tuning fork vibrator unit of the first embodiment is wire-bonded to a substrate, FIG. 9B is a side view thereof, and FIG. 9C is a bottom view thereof.

FIG. 10A is a top view illustrating a state where the tuning fork vibrator unit according to the first embodiment is mounted on a substrate and a supporter.
(B) is the front view, (c) is the side view.

11A is a front view showing a state where the tuning fork vibrator unit of the first embodiment is mounted on a stem, and FIG. 11B is a side view thereof.

FIG. 12 is a top view showing a state where the tuning fork vibrator unit of the first embodiment is mounted on a stem.

13A is a front view of the angular velocity sensor according to the first embodiment, and FIG. 13B is a side view thereof.

FIG. 14 is a top view of the angular velocity sensor according to the first embodiment.

FIGS. 15A to 15D are diagrams illustrating a manufacturing procedure of the tuning fork vibrator of the first embodiment.

16 (a) to (d) are views showing a manufacturing procedure of the tuning fork vibrator subsequent to FIG. 15 (d).

17A and 17B are diagrams showing a second embodiment of the angular velocity sensor and the method of manufacturing the angular velocity sensor according to the present invention, wherein FIG. 17A is a front view of the tuning fork vibrator, and FIG. 17B is a polarization direction of the tuning fork vibrator. (C) is a bottom view of the excitation axis and the detection axis showing the polarization direction of the tuning fork vibrator.

18A is a side view of the tuning fork vibrator of the second embodiment, FIG.
(B) is a rear view of the tuning fork vibrator of the second embodiment.

19A is a front view showing a state where the tuning fork vibrator of the second embodiment is held by a clamper block, FIG. 19B is a side view thereof, and FIG. 19C is a bottom view thereof.

20A is a partial detailed view of a clamper unit according to the second embodiment, and FIG. 20B is a diagram illustrating a state where the clamper unit is heated by a heater.

21A is a diagram illustrating an excitation state of the tuning fork vibrator according to the second embodiment, FIG. 21B is a side view illustrating a vibration state of the tuning fork vibrator when Coriolis force is generated, and FIG. It is a perspective view of the tuning fork vibrator in the state of (b).

FIG. 22 is a diagram illustrating an angular velocity detection circuit of the tuning fork vibrator according to the second embodiment.

23A is a front view showing a state where the tuning fork vibrator unit of the second embodiment is mounted on a substrate, FIG. 23B is a side view thereof, and FIG. 23C is a bottom view thereof.

FIG. 24 is a front view showing a state where the back surface of the tuning fork vibrator unit of the second embodiment is wire-bonded to a substrate.

25A is a front view showing a state where the surface of the tuning fork vibrator unit according to the second embodiment is wire-bonded to a substrate, FIG. 25B is a side view thereof, and FIG. 25C is a bottom view thereof.

FIG. 26A is a front view illustrating a state where the tuning fork vibrator unit according to the second embodiment is mounted on a substrate and a supporter;
(B) is a side view thereof.

FIG. 27 is a top view illustrating a state where the tuning fork vibrator unit according to the second embodiment is mounted on a substrate and a supporter.

FIG. 28A is a front view showing a state where the tuning fork vibrator unit of the second embodiment is mounted on a stem, and FIG. 28B is a side view thereof.

FIG. 29 is a top view showing a state where the tuning fork vibrator unit according to the second embodiment is mounted on a stem.

FIG. 30A is a front view of the angular velocity sensor according to the second embodiment, and FIG. 30B is a side view thereof.

FIG. 31 is a top view of the angular velocity sensor according to the second embodiment.

FIGS. 32A to 32D are diagrams illustrating a procedure for manufacturing the tuning fork vibrator of the second embodiment.

33 (a) to (e) are views showing a manufacturing procedure of the tuning fork vibrator subsequent to FIG. 32 (d).

34A is a perspective view of a conventional angular velocity sensor, and FIG.
FIG. 4 is a perspective view showing a state of the sensor when Coriolis occurs.

FIG. 35 is a characteristic diagram illustrating a resonance point of the non-resonant angular velocity sensor.

[Explanation of symbols]

21, 71 tuning fork vibrator 22, 72 base 22a, 22b, 72a, 72b fixed part 23 vibration axis (first vibration axis) 24 detection axis (first detection axis) 25a to 25d, 77a, 77b, 78a, 78b, 79a, 79b, 80
a, 80b Excitation electrodes 26a to 26f, 81a to 81c, 82a to 82f, 83a to 83f, 84
a to 84f Detection electrode 32 Clamper block (holding member) 34, 35 Arm member (fitting part) 58, 118 Angular velocity sensor 60, 121 Piezoelectric ceramic sheet material

Continuation of the front page (72) Inventor Haruhiko Sekino 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. No. 1 Matsushita Communication Industrial Co., Ltd. F-term (reference) 2F105 AA02 AA03 AA10 CC01 CD02 CD06 CD13

Claims (8)

[Claims] 1. A tuning fork vibration comprising a piezoelectric element having a base on which a protruding fixing portion is formed, and a first excitation axis and a first detection axis which are erected from the base and opposed to each other. The first excitation axis and the first detection axis are excited in the in-plane direction in which the first excitation axis and the first detection axis are close to and separated from each other, and the rotation axis is the same direction as the central axis of the tuning fork oscillator in the excited state. In an angular velocity sensor configured to detect a Coriolis force generated in a direction substantially perpendicular to the excitation direction as a deflection in a direction perpendicular to the plane of the tuning fork vibrator when an angular velocity is applied, a polarization direction of the first excitation axis A plurality of pairs of opposing electrodes on the front and back surfaces of the first excitation axis perform surface-perpendicular polarization so that the polarization directions are opposite to each other. As a polarization direction of the first detection axis, a table of the first detection axis is used. The counter electrode on both sides on the back A reverse surface perpendicular polarization is performed on the back surface, and an in-plane polarization is such that the central counter electrode at the center counter electrode on the front and back surfaces of the first detection axis has a zero potential between the counter electrodes on both sides. An angular velocity sensor characterized by performing the following. A second excitation electrode provided on a surface of the first excitation shaft and led to the base;
Two excitation electrodes provided on the back surface of the excitation shaft so as to face the two excitation electrodes and led to the base; and three excitation electrodes provided on the front surface of the first detection shaft and led to the base. Three detection electrodes, three detection electrodes provided on the back surface of the first detection axis so as to face the three detection electrodes, and led out to the base, and sandwiching the ridge of the projection-shaped fixing portion. And a holding member that holds the tuning fork vibrator by fitting the fixing portion to the fitting portion. The angular velocity sensor according to claim 1, wherein: 3. The tuning fork vibrator is mounted on a circuit board via the holding member.
An angular velocity sensor as described. 4. The acceleration sensor according to claim 3, wherein the tuning fork vibrator is mounted on a circuit board such that the rotation axis and the yaw rotation axis direction of the tuning fork vibrator are in the same direction. 5. A tuning fork vibrator is provided integrally with the tuning fork vibrator with a base of the tuning fork vibrator interposed therebetween, and has a polarization direction and an electrode facing the first excitation axis and having the same condition as the first detection axis. A second detection axis, provided integrally with the tuning fork vibrator with the base of the tuning fork vibrator interposed therebetween, facing the first detection axis and polarizing directions and electrodes under the same conditions as the first excitation axis; Having a second
An excitation axis, wherein when the first excitation axis and the second excitation axis are excited in an in-plane direction, the second excitation axis and the second excitation axis correspond to the excitation directions of the first excitation axis and the first detection axis. (2) The detection axis is excited in the opposite direction, and the first detection axis and the second detection axis vibrate in opposite directions perpendicular to the plane when Coriolis force is generated in a direction substantially perpendicular to the excitation direction. The angular velocity sensor according to any one of claims 1 to 4, wherein 6. The angular velocity sensor according to claim 1, wherein said holding member is made of tungsten, phosphor bronze, or stainless steel. 7. The method of manufacturing an angular velocity sensor according to claim 1, wherein, when manufacturing the tuning fork vibrator, a sheet material made of a piezoelectric element is prepared and the sheet material is subjected to photolithography. The excitation electrode and the detection electrode are collectively formed, and then a voltage is applied to the excitation electrode and the detection electrode to perform a polarization process collectively in the polarization direction. Then, the tuning fork vibrator is cut out from the sheet material. A method for manufacturing an angular velocity sensor, comprising: 8. A method for preparing the plated holding member, fitting a fixing portion of the tuning fork vibrator cut out of the sheet material into a fitting groove of the holding member, and then removing the holding member. 8. The method for manufacturing an angular velocity sensor according to claim 7, wherein the plating is heated to fill the gap between the fixing portion and the fitting groove.