JPH07163163A - Ultrasonic transducer - Google Patents

Abstract

(57) [Abstract] [Purpose] In the conventional ultrasonic transducer, the lead wire is used to connect the piezoelectric element and the external control circuit, so the quality is not stable and the number of man-hours is large. Therefore, there is a problem that the manufacturing cost becomes high. The present invention provides an ultrasonic transducer having a stable manufacturing quality with a lower manufacturing cost than conventional products. In FIG. 1, reference numeral 1 is a piezoelectric element having a front surface polarized into four regions and a back surface grounding electrode 8 formed thereon, and 19 is a grounding electrode pressed against the grounding electrode 8 of the piezoelectric element 1. The plates 4 are pressed into contact with the four regions of the piezoelectric element 4
Printed circuit board having two electrodes, 2 and 3 are piezoelectric elements 1
And a vibrating body 5 for holding the printed circuit board 4 and the grounding electrode 19 under pressure. For fastening, the vibrating bodies 2 and 3 and the piezoelectric element 1 and the grounding electrode plate 19 are clamped between the vibrating bodies 2 and 3. Bolt. According to the structure of the present invention, the lead wire is not required and the soldering is not necessary, so that the problem caused by the soldering work of the lead wire is solved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rod-shaped ultrasonic vibrator which serves as a power generating portion of a pencil type or an elongated type (slender type) ultrasonic motor.

[0002]

2. Description of the Related Art A pencil type, an elongated type or a slender type ultrasonic motor has been developed by the present applicant and has already been put to practical use by being mounted on an optical device such as a camera. The configuration of the rod-shaped ultrasonic vibrator of the ultrasonic motor will be described below with reference to FIG.

FIG. 29 is an exploded perspective view of a conventional rod-shaped ultrasonic vibrator.

The rod-shaped ultrasonic transducer is a disk-shaped piezoelectric element 1,
A first vibrating body 2 and a second vibrating body 3 formed of a metal material,
It is composed of an insulating sheet 22 made of a resin material, an electrode plate 19, and a fastening bolt 5 for fastening them.

Electrodes are provided on one end face and side faces of the piezoelectric element 1 in such a manner that the disk portion is divided into approximately four equal parts, and electrodes are provided on the other end faces on substantially the entire surface. The piezoelectric element 1 is polarized in the thickness direction for each electrode, and the electrodes facing each other with respect to the central axis are polarized in opposite directions. Each electrode has a lead wire 24 for feeding on the side surface of the piezoelectric element.
Are connected by soldering. A pair of electrodes facing each other is referred to as an A phase, and another pair of electrodes is referred to as a B phase.

When a voltage is applied to the phase A of the piezoelectric element, one electrode expands and the other compresses. When the voltage is an AC voltage, the vibrator causes bending vibration. When a voltage is similarly applied to the B phase, bending vibration occurs in a direction including the central axis and orthogonal to the vibration direction of the A phase. When an appropriate voltage phase difference is applied to the voltage applied to the B phase with respect to the voltage applied to the A phase, an arbitrary point of the oscillator causes elliptical motion.

When a moving body (not shown) is brought into pressure contact with an arbitrary point of the vibrator that is vibrating in this way, for example, the tip end surface of the first vibrating body 2, the moving body will generate surface particles of the vibrating body. The elliptical movement gives the feed force. The moving body is cylindrical,
By rotationally fixing the central axis of the moving body, the moving body is given a rotational motion to form an ultrasonic motor.

[0008]

The above-mentioned ultrasonic transducer has the following problems.

The piezoelectric element and the external control circuit are connected by a lead wire, and this lead wire is fixed to the piezoelectric element by soldering. In this structure, the lead wire comes off due to a soldering failure. Is likely to occur, causing a problem such as difficulty in reaching the solder melting temperature due to heat transfer to the piezoelectric element and the vibrating body. The vibration characteristics of the oscillator vary depending on the solder attachment state. Depolarization of the piezoelectric element may occur due to the temperature rise of the piezoelectric element during soldering. Therefore, for these reasons, it is difficult to always manufacture an ultrasonic transducer with stable performance by the conventional technology, and it is difficult to manufacture the ultrasonic vibrator due to the low work efficiency in the soldering process of the lead wire and the difficulty of quality control. There are problems such as high cost, low reliability of the ultrasonic transducer and concern about durability due to the use of lead wires for connecting the piezoelectric element and the external control circuit.

An object of the present invention is to provide an improved ultrasonic wave which is superior in reliability and durability to the above-mentioned conventional ultrasonic wave oscillator and which can be manufactured at a lower cost than the conventional ultrasonic wave oscillator. It is to provide a vibrator.

[0011]

A drawback of the above-mentioned conventional ultrasonic vibrator is that a lead wire is used as a means for electrically connecting the piezoelectric element and the external control circuit. Therefore, in the present invention, a large number of printed circuit (printed wiring) boards that do not require soldering work are used as the electrical connection means between the piezoelectric element and the external control circuit. And the printed circuit board is attached at the same time when the piezoelectric element and the oscillator main body are fastened by a fastening bolt which is a backbone member of the oscillator. Therefore, according to the improved ultrasonic transducer of the present invention, the soldering process of the lead wire is not necessary in the assembly process, and as a result, the assembly work efficiency is significantly improved and the defect rate is significantly reduced. Therefore, the manufacturing cost is reduced, and since the ultrasonic vibrator having stable performance can be manufactured at all times, the ultrasonic vibrator having high reliability and durability is provided.

[0012]

EXAMPLES Examples of an improved ultrasonic transducer according to the present invention will be described below with reference to FIGS. 1 to 28.

<Embodiment 1> FIG. 1 is an exploded perspective view of a rod-shaped ultrasonic transducer showing a first embodiment of the present invention. FIG. 2 is a front view showing the electrode arrangement of the piezoelectric element plate used in this example.

The rod-shaped ultrasonic vibrator includes a disk-shaped piezoelectric element plate 1, a first vibrating body 2 made of a metal material, a second vibrating body 3, and a printed circuit board 4 for supplying electric power to each electrode of the piezoelectric element plate. An electrode plate 19 for setting the common electrode 8 of the piezoelectric element plate to the GND potential, and a fastening bolt 5 for fastening them.
It is composed of

As shown in FIG. 2, an electrode 6 is arranged on one surface of the piezoelectric element plate 1 so as to divide the entire circumference of the piezoelectric element plate into four equal parts, and a common electrode is provided on the other surface of the piezoelectric element plate. 8 is arranged on the substantially entire surface. The piezoelectric element plate is polarized in the thickness direction for each electrode. As shown in FIG.
6B1 and 6A2 and 6B2 are polarized in opposite directions. Electrodes 6A1 and 6A2 are phase A, electrodes 6B1 and 6B
Let B be phase 2.

A substrate electrode 7 is arranged on the disk portion of the printed circuit board 4 in such a manner that the circumference of the disk portion is roughly divided into four equal parts. The substrate electrodes 7 are the electrodes of the piezoelectric element plate 1 and 7A1-6A1, 7A2.
-6A2, 7B1-6B1, 7B2-6B2 are arranged in contact with each other. Further, the printed circuit board 4 is provided with a connection terminal 9 for connecting to a control circuit (not shown), and 7A1-9A1 and 7A2-9A are provided by lead electrodes on the printed circuit board.
2, 7B1-9B1 and 7B2-9B2 are connected.

The electrodes 6 of the piezoelectric element plate 1 and the electrodes 7 of the printed circuit board 4, and the common electrode 8 and the electrode plate 19 are brought into contact with each other, and an electric field is applied between the printed circuit board and the electrode plate 19 having the GND electrode 19 GND. Electric power is supplied to the element plate 1.

Connection terminals 9A1 and 9A2 and GND electrode 1
By applying an electric potential to 9, the electric potential is applied to the A phase of the piezoelectric element. Similarly, the connection terminals 9B1 and 9B2 and the GND electrode 1
An electric potential is applied to the B-phase by applying an electric potential between 9 and 9. A lead wire, a flexible substrate, or the like is connected to the connection terminal and the GND electrode 19 by a soldering connector or the like, and is connected to an external control circuit.

When an electric field is applied to phase A, electrode 6A
Since 1 and 6A2 are polarized in opposite directions, the oscillator
A force for bending in the X direction shown in is generated. Similarly, when an electric field is applied to the B phase, a bending force is generated in the Y direction that is substantially orthogonal to the X direction.

When the applied voltage is an AC voltage and an AC frequency near the natural frequency of bending vibration of the vibrator is selected and applied to the piezoelectric element, periodic and stable bending vibration of the vibrator can be obtained. When the voltage applied to the B phase is given an appropriate time phase difference with respect to the voltage applied to the A phase, any point of the vibrator vibrates so that its locus draws an ellipse. When a moving body (not shown) is brought into pressure contact with an arbitrary point of the vibrator vibrating in this way, for example, the upper end surface of the first vibrating body 2, the moving body is fed by the elliptic motion of the surface particles of the vibrator. Is given the power of.

The piezoelectric element plate 1 is arranged near the maximum strain position of the vibrator. Since the printed board 4 is arranged at a position adjacent to the piezoelectric element plate 1, the distortion of the printed board 4 due to the deformation of the vibrator becomes large. To reduce the energy consumption due to the damping of the oscillator,
For the printed circuit board, it is desirable to select a material that can obtain a material with small attenuation. In this embodiment, the base of the printed circuit board is made of a ceramic material to form a vibrator with a small amount of attenuation. It is also possible to select a metal material such as Al as the base of the printed circuit board.

When a ceramic plate is used as the base of the printed circuit board in order to suppress the increase of the total length of the vibrator and the increase of the attenuation amount of the vibrator as described above, the thickness of the ceramic plate is 0.8 mm or less. It is desirable to do.
When a metal material is used, it is desirable to use a material such as Al or Fe that has small vibration damping. When the metal substrate is used as the base substrate, an insulating layer is required between the base substrate and the electrode, but since this insulating layer is usually made of a resin material, vibration damping becomes large. In order to reduce the consumption of vibration energy by the printed circuit board, the insulating layer is
It is desirable that the thickness is μm or less.

A printed circuit board is used to supply power to the piezoelectric element,
By using the fastening structure of the vibrator, complicated work such as bonding is not required, and simple and stable power supply can be performed.

<Embodiment 2> FIG. 3 shows a second embodiment of the vibrator of the present invention.
It is an example of. In this embodiment, electrodes are attached to both surfaces of the piezoelectric element plate 1, polarized in the thickness direction (not divided into four regions, and polarized to the same polarity on the entire surface), and then the electrode on one surface is removed by polishing or the like. . It is arranged so that the surface from which the electrode is removed and the electrode surface of the printed board are in contact with each other.

Power is supplied to the phase A by the electrodes 7A1 and 7A2 of the printed circuit board 4, but a voltage opposite to that of the substrate electrode 7A1 is applied to the substrate electrode 7A2. If an AC voltage is applied, bending vibration is applied to the vibrator. Similarly, a voltage is applied to the B phase and bending vibration is applied.

<Embodiment 3> FIG. 4 is an exploded perspective view of a rod-shaped ultrasonic transducer showing a third embodiment of the present invention.

The structure of the vibrator is the same as that of the first embodiment shown in FIG. 1, but a flexible printed circuit board 20 is used as the printed circuit board 4, and the disk portion also serving as the electrode plate 19 shown in FIG. It has a disc-shaped electrode 7 GND. The printed circuit board 20 also has a connection terminal 9 for connecting to an external control circuit (not shown).

The substrate electrodes 7A1 and 7A2 are electrically connected by a printed pattern at the inner diameter portion on the printed circuit board, and 7A1 is electrically connected to the connection terminal 9A. The board electrodes 7B1 and 7B2 are conducted outside the vibrator outer diameter of the printed circuit board disk portion,
7B1 is electrically connected to the connection terminal 9B. Printed circuit board 20
Substrate electrodes and piezoelectric element electrodes are 7A1-6A1, 7A2-
6A2, 7B1-6B1, 7B2-6B2, and 7GN
It is arranged at a position where D and the electrode 8 are in contact with each other.

By arranging the piezoelectric element plate 1 and the printed circuit board 20 in this way and applying a voltage to the connection terminal 9A, A
The phase is driven, and the B phase is driven by applying a voltage to the connection terminal 9.

FIG. 5 shows the state of deformation of the rod-shaped vibrator when bending deformation occurs. The force exerted by the unit area dA of the piezoelectric element on the bending of the vibrator in the X direction increases in proportion to the distance x of the region dA from the central axis of the vibrator in the X direction. That is, it is given by dA × x. When the bending deformation is generated in the vibrator, the generated force can be effectively used by using the outer diameter side of the piezoelectric element. By arranging the printed pattern for conducting the substrate electrode 7 on the inner diameter side and the outer side of the outer diameter of the vibrator, the outer diameter portion of the piezoelectric element can be effectively used, and an efficient vibrator can be formed.

The flexible printed board is formed by adhering a copper foil to a resin sheet as a base material with an adhesive. Since the resin sheet and the adhesive have large vibration damping, the vibration damping of the entire vibrator becomes large and the efficiency of the vibrator decreases.

In order to examine the change in the vibration damping amount of the vibrator due to the printed circuit board, a test-use vibrator was prepared and compared. The outer shape of the vibrator has a diameter of 8 mm and a total length of 13.5 mm. The first and second vibrators are made of BS material, and the fastening bolts are made of free-cutting steel plated with KN. Piezoelectric element is P
It is ZT and has a thickness of 0.4 mm. The oscillator is used for bending primary vibration and has a resonance frequency of 64 kHz.

In the flexible printed circuit board, the base sheet was made of polyimide resin and had a thickness of 25 μm, the electrodes were copper foil sheets and had a thickness of 35 μm, and two types of printed circuit board materials having different adhesive thicknesses were prepared. This printed circuit board material is for investigating the change of the attenuation amount of the vibrator, and the power supply to the piezoelectric element is performed by the electrode plate.

FIG. 6 shows a comparison of the Q values (representing the amount of attenuation, the larger the value, the smaller the attenuation) of the vibrators at the resonance frequency when using each printed circuit board material. By using a printed board without an adhesive layer, it is possible to form an efficient vibrator with a small increase in attenuation.

<Fourth Embodiment> FIG. 7 is an exploded perspective view of an ultrasonic transducer according to a fourth embodiment of the present invention. FIG. 8 shows details of a part of the flexible printed circuit board used in this embodiment.

The piezoelectric element plate 1, the first vibrating body 2 and the second vibrating body 3, and the fastening bolts 5 used in this embodiment have the same shape and material as those in the above embodiment. The arrangement and fastening of each member is the same, but an insulating sheet 22 made of an electrically insulating material is arranged between the first vibrating body and the flexible printed board 20.

On the front surface of the disk portion of the flexible printed circuit board 20, there is provided a substrate electrode 7 which is obtained by dividing the disk portion into four equal parts, as in the above-mentioned embodiment. As shown in FIG. 101A1, 101B1, 101B
2 is arranged and is electrically connected to the back surface. A conductive electrode 102 is arranged on the back surface and is electrically connected through through holes 101A1 and 101A2 and 101B1 and 101B2. With this structure, the substrate electrodes 7A1 and 7A
2, 7B1 and 7B2 are electrically connected, and the A phase and B of the piezoelectric element
An electrical signal is applied to each phase.

The conductive electrodes 102 are arranged concentrically on the disk portion so as to cover substantially the entire surface of the disk portion. This is to prevent deviation of the resonance frequency and bias of the vibration direction due to having a non-uniform contact portion in the vibrator, and to improve the propagation of the vibration wave.

By thus conducting the board electrodes on the back surface of the printed board, the area of the board electrodes can be made as large as possible, and the electrode area of the piezoelectric element also becomes large.
As a result, a vibrator having a large output and high efficiency can be provided.

In this embodiment, the flexible printed circuit board and the resin sheet 22 are shown as separate bodies.
The same effect can be obtained by applying a cover coat to 0 to ensure the insulation of the conducting electrode 102.

<Embodiment 5> FIG. 9 is an exploded perspective view of a rod-shaped ultrasonic transducer showing a fifth embodiment of the present invention. FIG. 10 is a detailed view of a part of the flexible printed board 20 used in this embodiment.

As shown in FIGS. 9 and 10, in the disk portion of the flexible printed board 20, substrate electrodes 7 that divide the circumference into approximately four equal parts are arranged on both sides of the disk portion. As shown in FIG. 10, the substrate electrodes 7A1 and 7A2 are connected by the conductive pattern 103a on the front surface of the printed circuit board, and the substrate electrode 7B3 is connected.
And 7B4 are connected by a conductive pattern 103b on the back surface of the printed board. Each substrate electrode 7 is electrically connected to the substrate electrode on the opposite surface through the through hole 101. The board electrode 7A1 and the connection terminal 9A, and the board electrode 7B1 and the connection terminal 9B are connected by a conductive pattern on the printed board.

The substrate electrode 7GND is provided to give the piezoelectric element 1 a GND potential. The board electrodes 7GND are provided on both sides of the printed board, and are electrically connected between the two sides by through holes 104.

The respective parts constituting the vibrator are arranged as shown in FIG. In this embodiment, two piezoelectric elements are used, and power is supplied to each piezoelectric element by disposing the printed circuit board so as to be sandwiched by the piezoelectric elements.

With such a structure, it is possible to increase the number of piezoelectric elements without complicating the structure for supplying power to the piezoelectric elements, and it is possible to form a vibrator capable of obtaining a large output.

<Embodiment 6> FIG. 11 is a longitudinal sectional view of a rod-shaped ultrasonic transducer showing the structure of a sixth embodiment of the present invention.

In this example, six piezoelectric element plates 1 are used, but a vibrator having an even number such as four or eight can be easily formed by using the same structure.

As shown in FIG. 12, the flexible printed circuit board 20 has four disk portions 20R1 to 20R4,
The disk portions 20R1, 20R2, 20R3 have the same substrate electrode structure as in FIG. GND on the disk part 20R4
Electrodes 7 GND for potential are arranged on both sides, and conduction is provided on both sides by through holes. The connection terminal and the substrate electrode are connected by 9A-7A, 9B-7B, 9G-7GND.

Disk portions 20R1, 20 of the printed circuit board 20
The piezoelectric element plates 1 are arranged so as to sandwich R2 and 20R3. The surface of the piezoelectric element plate 1 having the electrodes 6 is the printed circuit board 20.
The electrode plate 21 made of metal and arranged on the opposite surface of the piezoelectric element is in pressure contact with the fastening bolt 5 and is electrically connected. The first vibrating body 2, the second vibrating body 3, and the fastening bolt 5 are made of a metal material, and the second vibrating body 3
Are in contact with the printed circuit board disk portion 20R4, so that they are all at the GND potential. By arranging in this way, a voltage is applied to all the piezoelectric elements.

With the structure of this embodiment, the number of piezoelectric elements can be easily made plural, and a vibrator which produces a large output can be easily produced.

In the above embodiments, the piezoelectric element plate is divided into four, and driving by two phases of A and B is shown, but the present invention is not limited to this, and the piezoelectric element plate and each electrode of the piezoelectric element are connected. It is also possible to divide the printed circuit board for power supply into an arbitrary number and drive by applying voltages of two or more phases.

FIG. 13 shows an example in which the flexible printed circuit board 20 and the piezoelectric element plate 1 are divided into six parts and driven by three phases.

FIG. 14 shows an example in which the flexible printed circuit board 20 and the piezoelectric element plate 1 are divided into eight and driven by four phases.

The structure for driving the vibrator by applying voltages of two or more phases is not limited to this embodiment, and can be easily implemented in other embodiments.

<Embodiment 7> FIG. 15 is an exploded perspective view of a rod-shaped ultrasonic vibrator showing a seventh embodiment of the present invention. FIG. 16 is a plan view showing the electrode arrangement of the piezoelectric element plate 1 used in this example.

The vibrator is a disk-shaped piezoelectric element plate 1, a first vibrating body 2 and a second vibrating body 3 made of a metal material, and a printed circuit board 4 for connecting each electrode of the piezoelectric element plate and an external control circuit. An electrode plate 19 for setting the common electrode 8 of the piezoelectric element plate to the GND potential, and a fastening bolt 5 for integrating them.

As shown in FIG. 15, an electrode 6 is arranged on one surface of the piezoelectric element plate 1 so as to divide the circumference of the piezoelectric element into approximately four equal parts, and a common electrode 8 is provided on the opposite surface of the piezoelectric element. Almost all over the place. The piezoelectric element plate 1 is polarized in the thickness direction for each electrode, and as shown in FIG.
B1 and 6B2 are polarized in opposite directions. Electrode 6A is A
The phase, the electrodes 6B1 and 6B2 are the B phase, and the electrode 6S is the sensor phase.

On the disc portion of the printed circuit board 4, the substrate electrodes 7 are arranged in such a manner that the circumference of the disc portion is roughly divided into four. The substrate electrode 7 includes the electrodes 6 of the piezoelectric element 1 and 7A-6A, 7B1-6.
B1, 7B2-6B2, 7S-6S are arranged in contact with each other. Further, the printed circuit board is provided with a connection terminal 9 and is connected to the printed circuit board 4 by a printed pattern.
A-9A, 7B1-9B1, 7B2-9B2, 7S-9
Connected by S.

Power is supplied to the piezoelectric element plate 1 by applying a voltage between the connection terminal 9 of the printed board and the electrode plate 19. By applying a voltage to the connection terminal 9A, the voltage is driven to the A phase of the piezoelectric element. Similarly, the connection terminals 9B1 and 9B
By applying a voltage to 2, the B phase is driven. A lead wire, a flexible printed circuit board, or the like is soldered to the connection terminal 9 and the electrode 19 and fixed by a connector or the like to be connected to an external control circuit.

When voltage is applied to phase A, electrode 6A
Causes distortion, and the vibrator bends in the X direction shown in FIG. Similarly, when a voltage is applied to the B phase, the B phase is bent in the Y direction which is substantially orthogonal to the X direction. When the applied voltage is an AC voltage and an AC frequency near the natural frequency of bending vibration of the vibrator is selected, periodic and stable bending vibration of the vibrator can be obtained. Further, when the voltage applied to the B phase is given an appropriate time phase difference with respect to the voltage applied to the A phase, any point of the vibrator vibrates so that the locus draws an ellipse. When a moving body (not shown) is brought into pressure contact with an arbitrary point of the vibrator vibrating in this way, for example, the upper end surface of the first vibrating body 2, the moving body causes an elliptic motion of surface particles of the vibrator, The power of feeding is given.

The electrode 6S of the piezoelectric element is distorted by the bending deformation of the vibrator, and charges are generated by the piezoelectric effect. The vibration state of the vibrator is monitored by detecting this electric charge from the connection terminal 9S. The electrode 6S is arranged at a position shifted by 0 rad with respect to the A-phase piezoelectric element. FIG. 17 shows the relationship between the voltage applied to the A-phase piezoelectric element and the phase difference between the output signals of the sensor phase (hereinafter referred to as θA-S) and the magnitude (Vs) of the output signal of the sensor phase at this time. Shown in. When the vibrator is driven in the bending primary vibration mode, the phase difference θA-S at the resonance frequency Fr is (90π / 18) for both CW (clockwise direction) and CCW (counterclockwise direction).
0) rad, which gradually shifts at a frequency higher than the resonance frequency. The magnitude (Vs) of the output signal has a maximum value in the vicinity of the resonance frequency, and gradually decreases at frequencies higher than the resonance frequency. Therefore, the relationship between the input frequency and the resonance frequency of the vibrator can be monitored by observing the phase difference θA-S and the magnitude of the output signal when vibration is applied, and the vibrator can be stably driven.

The piezoelectric element plate 1 is arranged near the maximum strain position of the vibrator. Since the printed circuit board 4 is arranged adjacent to the piezoelectric element plate 1, the distortion of the printed circuit board 4 due to the deformation of the vibrator becomes large. In order to suppress the consumption of vibration energy due to the damping of the vibrator, it is desirable that the printed board 4 be made of a material with small damping. In this embodiment, a ceramic material is used as the base material of the printed circuit board 4 to form a vibrator with a small amount of attenuation.
It is also possible to select a metal material such as aluminum as the base of the printed circuit board.

In order to suppress the increase in the total length of the vibrator and the increase in the attenuation amount of the vibrator as described above, when the ceramic plate is used as the base of the printed board, the plate thickness is 0.8 mm or less. desirable. When a metal material is used, it is desirable to use a material such as aluminum having a small vibration damping. When using a metal material as the base substrate,
An insulating layer is required between the base substrate and the electrode plate, but since a resin material is usually used for this insulating layer, vibration damping becomes large. Therefore, it is desirable that the insulating layer provided on the printed board has a thickness of 80 μm or less.

<Embodiment 8> FIG. 18 is an exploded perspective view showing an eighth embodiment of the present invention, which is a modification of the second embodiment shown in FIG.

The piezoelectric element plate 1 is provided with electrodes on both sides, polarized in the thickness direction (polarized to the same polarity on all surfaces without being divided into four regions), and then the electrodes on one surface are removed by polishing or the like. It is arranged so that the surface from which the electrodes have been removed contacts the electrode surface of the printed circuit board 4.

Power is supplied to the phase A by the board electrode 7A of the printed board 4. B by the substrate electrodes 7B1 and 7B2
Power is supplied to the phases, but a voltage opposite to that of 7B1 is applied to the substrate electrode 7B2. If an AC voltage is applied, bending vibration is applied to the vibrator. Further, the substrate electrode 7S monitors the vibration state of the vibrator.

<Embodiment 9> FIG. 19 is an exploded perspective view of a rod-shaped ultrasonic vibrator showing a ninth embodiment of the present invention. FIG. 20 is a detailed view of a part of the flexible printed board 20 used in this embodiment.

The structure of the vibrator is almost the same as that of the fifth embodiment shown in FIG. A flexible printed circuit board 20 is used as the printed circuit board 4, and the printed circuit board 20 has a disk portion also serving as the electrode plate 19 shown in FIG. 15, and is provided with a disk-shaped electrode 7GND. The printed circuit board 20 also has a connection terminal 9 for connecting to an external control circuit (not shown).

As shown in FIG. 20, the disk electrode of the flexible printed circuit board is provided with the substrate electrodes 7 which divide the circumference into four equal parts on both sides of the disk part. The board electrodes 7A2 and 7A3 are connected to each other on the back surface of the printed board by a conductive pattern 103a in the inner diameter portion. The board electrodes 7B1 and 7B2 are connected on the front surface of the printed board by a conductive pattern 103b outside the outer diameter of the vibrator. The board electrodes 7 on both sides are electrically connected by through holes 101 provided in the printed board. Substrate electrodes and connection terminals are 7A1-9A, 7B1-9
B, 7S-9S are connected by a conductive pattern on the printed circuit board.

The substrate electrode 7 GND is provided to give the piezoelectric element 1 a GND potential. The board electrodes 7 GND are provided on both surfaces of the printed board, and are electrically connected between the both surfaces by the through holes 104. The board electrode 7GND and the connection terminal 9GND are electrically connected by a conductive pattern on the printed board.

<Embodiment 10> FIG. 21 is an exploded perspective view of a rod-shaped ultrasonic transducer showing a tenth embodiment of the present invention. Figure 2
2 is a partial detailed view of a flexible printed board used in this embodiment and a plan view showing an electrode configuration of a piezoelectric element.

The structure of the vibrator is almost the same as that of the fifth embodiment shown in FIG. 9, and one piezoelectric element 1b of the two piezoelectric element plates has four driving electrodes as shown in FIG. And 1
One sensor electrode 7S is provided. The electrode 7S has a shape symmetrical with the X axis. Substrate electrodes 7 are provided on both surfaces of the printed circuit board 20 at positions corresponding to the respective electrodes of the piezoelectric element.

In the seventh to ninth embodiments, the piezoelectric element 1
The sensor phase is provided by using approximately 1/4 of the above, and therefore the area of the piezoelectric element used for driving is greatly reduced. However, in the present embodiment, the piezoelectric element for sensor and the electrode for sensor are made smaller. To prevent the reduction of driving force.

FIG. 23 shows the state of deformation of the rod-shaped vibrator when bending deformation occurs. The force that the unit area dA of the piezoelectric element acts on the bending of the vibrator in the X direction is given by the product of the length x of the region dA in the X direction from the central axis of the vibrator. That is, when the bending deformation is generated in the vibrator, the force generated by the piezoelectric element can be effectively used by using the outer diameter side of the piezoelectric element. By providing the sensor phase on the inner diameter side of the piezoelectric element, the region of the piezoelectric element used for driving can be arranged at a position where a large amount of force is generated, and a vibrator having a large amount of deformation and high efficiency can be created.

<Embodiment 11> FIG. 24 is a longitudinal sectional view of a rod-shaped ultrasonic transducer according to an eleventh embodiment of the present invention, showing an example in which six piezoelectric element plates 1 are used. The structure of the vibrator using an even number such as eight can be easily formed in the same manner as this embodiment.

As shown in FIG. 25, the flexible printed circuit board 20 has four disc parts 20R.
1 has a substrate electrode structure similar to that of FIG. 9, and is provided with driving electrodes 7A and 7B and a sensor phase electrode 7S. The disk portions 20R2, 20R3 are provided with electrodes 7A, 7B for the A and B phases.

Disk part 2 of flexible printed circuit board 20
The piezoelectric element plates 1 are arranged so as to sandwich 0R1, 20R2, and 20R3. However, the disk portion 20 of the printed circuit board 20
The surface having the electrode 6 of the piezoelectric element 1 is arranged on the surface of R1 shown in the drawing, and the surface having the electrode 6 of the piezoelectric element 1 is arranged on the other surface of the disk portion. A metal electrode plate 21 is arranged in contact with the common electrode 8 of the piezoelectric element 1. The electrode plate 21 is brought into pressure contact with the fastening bolt 5 to be electrically conducted. First vibrating body 2
The second vibrating body 3 and the fastening bolts 5 are made of a metal material, and the second vibrating body 3 further includes the printed circuit board disk portion 20R4.
Since they are in contact with, they all become GND potential,
The GND potential is applied to all the piezoelectric elements 1.

In this embodiment, the piezoelectric element used as the sensor layer is minute compared to the total volume of the piezoelectric element 1, and the piezoelectric element is effectively used for driving.

In each of the above-described embodiments, the piezoelectric element is divided into four, and driving by two phases of the A and B phases has been shown. However, the present invention is not limited to this, and for supplying power to the piezoelectric element and each electrode of the piezoelectric element. The printed circuit board electrodes may be divided into an arbitrary number and driven by a voltage load of two or more phases.

FIG. 26 shows an example in which the flexible printed circuit board 20 and the piezoelectric element 1 are divided into six parts and driven by three phases.

FIG. 27 shows an example in which the flexible printed circuit board 20 and the piezoelectric element 1 are divided into eight and driven by four phases.

The driving configuration of the vibrator by these two or more sets of voltage loads can be easily implemented in other embodiments of the present invention.

FIG. 28 is a vertical sectional view of a rod-shaped ultrasonic motor using the vibrator described above. Fastening bolt for oscillator 5
Has a small-diameter strut portion 5p at its tip, and the fixing member 15 fixed to the tip of this strut portion 5p enables the motor itself to be fixed, and also serves to support rotation of a moving body or the like. ing. The moving body 18 contacts the tip end surface of the first elastic body 2, and pressure is applied from the fixed member 15 via the bearing member 13 and the gear 14 to the spring case 17 installed in the moving body 18.
It is given by pressing the coil spring 16 of.

[0084]

As described above, in the ultrasonic transducer of the present invention, the use of the lead wire is stopped and the printed wiring board is used as the connecting means for electrically connecting the piezoelectric element and the external control circuit. In addition, since the printed wiring board is sandwiched between the piezoelectric element and the vibrator body by using the tightening force of the fastening bolts of the vibrator, the conventional soldering work of the lead wire becomes unnecessary. Therefore, various problems caused by soldering work, namely, unstable quality, low reliability, poor work efficiency, high manufacturing cost, concern about durability, etc. are solved, and quality is solved. There is provided an ultrasonic transducer which is stable, highly reliable, and can be manufactured at low cost. Further, according to the structure of the present invention, it is possible to easily manufacture an ultrasonic transducer having a higher output than a conventional product at low cost.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an ultrasonic transducer according to a first embodiment of the present invention.

FIG. 2 is a polarization arrangement diagram of a piezoelectric element of the ultrasonic vibrator of FIG.

FIG. 3 is an exploded perspective view of an ultrasonic transducer according to a second embodiment of the present invention.

FIG. 4 is an exploded perspective view of an ultrasonic transducer according to a third embodiment of the present invention.

FIG. 5 is a diagram for explaining a state where a driving force is generated in the ultrasonic transducer.

6 is a diagram showing the configuration and mechanical properties of a flexible printed circuit board used in the ultrasonic transducer shown in FIG.

FIG. 7 is an exploded perspective view of an ultrasonic transducer according to a fourth embodiment of the present invention.

8 is a diagram showing a configuration of a printed circuit board using the ultrasonic transducer of FIG.

FIG. 9 is an exploded perspective view of an ultrasonic transducer according to a fifth embodiment of the present invention.

10 is a diagram showing a configuration of a printed circuit board used in the ultrasonic transducer of FIG.

FIG. 11 is a schematic vertical sectional view of an ultrasonic transducer according to a sixth embodiment of the present invention.

12 is a diagram showing the configuration of a printed circuit board used in the ultrasonic transducer shown in FIG.

13 is a diagram showing another embodiment of a printed circuit board applicable to the ultrasonic transducer of FIG.

FIG. 14 is a diagram showing a configuration of a printed circuit board and a piezoelectric element applicable to the ultrasonic transducer of the type shown in FIG.

FIG. 15 is an exploded perspective view of an ultrasonic transducer according to a seventh embodiment of the present invention.

16 is a diagram showing a polarization arrangement of piezoelectric elements of the ultrasonic vibrator of FIG.

FIG. 17 is a diagram for explaining the output of the sensor unit of the ultrasonic transducer of FIG.

FIG. 18 is an exploded perspective view of an ultrasonic transducer according to an eighth embodiment of the present invention.

FIG. 19 is an exploded perspective view of an ultrasonic transducer according to a ninth embodiment of the present invention.

20 is a diagram showing a configuration of a printed wiring board of the ultrasonic transducer of FIG.

FIG. 21 is an exploded perspective view of an ultrasonic transducer according to a tenth embodiment of the present invention.

22 is a diagram showing a configuration of a piezoelectric element and a printed wiring board used in the ultrasonic transducer of FIG.

23 is a view for explaining a driving force generation state in the ultrasonic transducer shown in FIG.

FIG. 24 is a schematic vertical sectional view of an ultrasonic transducer according to an eleventh embodiment of the present invention.

25 is a view showing the structure of a printed wiring board used in the vibrator of FIG.

FIG. 26 is a diagram showing a configuration of a piezoelectric element and a printed wiring board used in the ultrasonic transducer of the format shown in FIG.

FIG. 27 is a diagram showing a configuration of a piezoelectric element and a printed circuit board used in the ultrasonic transducer of the type shown in FIG. 24.

FIG. 28 is a vertical cross-sectional view of an ultrasonic motor configured using the ultrasonic vibrator of the present invention.

FIG. 29 is an exploded perspective view of a conventional ultrasonic transducer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric element 2 ... 1st vibrating body 3 ... 2nd vibrating body 4 ... Printed circuit board 5 ... Fastening bolt 6 ... Piezoelectric element electrode 7 ... Board electrode 8 ... Piezoelectric element common electrode 9 ... Connection terminal 13 ... Bearing member 14 ... Gear 15 ... Fixing member 16 ... Coil spring 17 ... Spring case 18 ... Rotor 19 ... Electrode plate 20 ... Flexible printed circuit board 21 ... Electrode plate 22 ... Insulating sheet 101 ... Through hole 102 ... Conductive electrode 103 ... Conductive pattern

Claims (10)

[Claims] 1. At least one piezoelectric element having two or more sets of electrodes on at least one end surface thereof, and at least one piezoelectric element disposed so as to oppose the two end surfaces of the piezoelectric element and holding the piezoelectric element under pressure. A rod-shaped ultrasonic transducer comprising two elastic bodies and a fastening member for fastening and fixing the piezoelectric element and the elastic body to each other, wherein the ultrasonic transducer is arranged between the piezoelectric element and the elastic body. A printed wiring board is sandwiched between the piezoelectric element and the elastic body by the fastening member, and an electrode portion connected to the electrode of the piezoelectric element is provided on the printed wiring board. An ultrasonic transducer having a connection terminal with a control circuit. 2. At least one piezoelectric element having two or more sets of electrodes and a sensor electrode on the end surface, and arranged to face two end surfaces of the piezoelectric element, and to hold the piezoelectric element under pressure. In a rod-shaped ultrasonic vibrator, comprising: at least two elastic bodies, and a fastening member that fastens and secures the piezoelectric element and the elastic body to each other, between the piezoelectric element and the elastic body. A printed wiring board that is arranged and clamped and held between the piezoelectric element and the elastic body by the fastening member is provided, and the printed wiring board is provided with an electrode portion that is connected to each electrode of the piezoelectric element. An ultrasonic transducer characterized by being provided with a connection terminal for connection with an external control circuit. 3. The ultrasonic vibration according to claim 1, wherein the printed wiring board has electrode portions on both sides and has through holes for electrically connecting the electrode portions on both sides. Child. 4. The ultrasonic transducer according to claim 1, wherein the piezoelectric element is polarized in the thickness direction and has an electrode only on one end surface. 5. The piezoelectric element and the printed wiring board each have an annular disc shape with a hole formed at the center thereof, and the elastic body has an annular body or a hole having a hole formed at the center thereof. The fastening member is a thick cylinder, the fastening member is a shaft-shaped member that is inserted through the holes of the piezoelectric element, the printed wiring board, and the elastic body, and the wiring that connects the electrode portions of the printed wiring board is the printed wiring. The ultrasonic transducer according to claim 1, wherein the ultrasonic transducer is provided along the hole edge of the hole of the substrate and the outer peripheral edge of the printed wiring board. 6. The ultrasonic transducer according to claim 1, wherein the printed wiring board is a flexible printed board. 7. The ultrasonic vibration according to claim 1, wherein the printed wiring board is a flexible printed board and has no adhesive layer between the base sheet and the electrode portion. Child. 8. The ultrasonic transducer according to claim 1, wherein the printed wiring board has a ground electrode portion connected to the ground electrode of the piezoelectric element. 9. The ultrasonic transducer according to claim 2, wherein the size of the sensor electrode is designed to be smaller than the size of other driving electrodes. 10. The sensor electrode is arranged on the inner peripheral side of other driving electrodes.
Ultrasonic transducer.