JPH07213081A - Multilayer piezoelectric element and vibration-wave drive device - Google Patents

Abstract

PURPOSE:To form traveling waves whose wave number is one or more in the circumferential direction by a method wherein a plurality of first piezoelectric-element sheets which are arranged in the circumferential direction at intervals of an odd multiple of a 1/4 wavelength and second piezoelectric-element sheets in which electrode parts have been formed on the whole of one side of a piezoelectric ceramic are disposed alternately. CONSTITUTION:A GND electrode 14G with a length of a 1/4 wavelength is formed in the circumferential direction on a piezoelectric-element sheet (PE) 4 at the outermost layer. Power-supply electrodes 14A, 14B for an A-phase and a B-phase are formed on both sides of the GND electrode 14G. In a PE sheet 2 as a second sheet from the upper part, a PE 2 as a fourth sheet and a PE 3 in the lowermost layer, first electrodeless parts 15-1 in which an electrode with a length of a 3/4 wavelength is not formed are formed so as to be identical to the center in the circumferential direction of the GND electrode 14G of the PE 4. In addition, second electrodeless parts 15-1 in which an electrode with a length of a 1/4 wavelength is not formed are formed in symmetric positions of the first electrodeless parts 15-1. Then, positive and negative electrodes 12A, 13A, 12B, 13B for an A-phase and a B-phase which has a length of a 1/2 wavelength are formed on both sides between both electrodeless parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated piezoelectric element and a vibration wave driving device represented by an ultrasonic motor using bending traveling waves using the laminated piezoelectric element.

[0002]

2. Description of the Related Art Conventionally, an annular or disk-shaped ultrasonic motor has been disclosed in, for example, Japanese Patent Publication No. 1-17354, in which an electrostrictive element is formed on an elastic body having a low vibration damping property such as metal. Alternatively, a piezoelectric element is fixed to a vibrator, a moving body (contact body) is brought into pressure contact with the surface of the elastic body, and high-frequency voltages having different phases in time are applied to parallel electrode groups of the electrostrictive element or the piezoelectric element. By applying the voltage, the moving body (contact body) is (relatively) driven.

In the piezoelectric element used in this vibrator, a large number of divided electrodes are arranged on one surface side, and a full surface electrode is provided on the opposite surface side to be joined to the elastic body. The plurality of electrodes on one side are composed of a plurality of A-phase and B-phase electrode groups used for driving, and these two-phase electrode groups are positioned relative to each other by a quarter wavelength or an odd multiple of a quarter wavelength. The plurality of piezoelectric elements of each group, which are arranged with a spacing of λ and are polarized in different directions, have a spacing of ½ wavelength, and the piezoelectric elements of the same group having different polarization directions. When a high-frequency voltage is simultaneously applied to the two, vibration of one wavelength is excited, and if a plurality of sets of this are prepared, standing waves with a wave number corresponding to the number are formed, and as a result, traveling waves of one or a plurality of wave numbers are generated. Be excited.

[0004]

However, since the above-mentioned conventional electrostrictive or piezoelectric element has a single layer structure, it is necessary to drive an ultrasonic motor using this piezoelectric element with a practical output of several tens. It is necessary to apply a high frequency voltage of Volt,
The voltage of the battery, which is the power source for portable devices such as cameras, was not sufficient, and it was necessary to prepare a booster circuit.

Here, there is known a laminated ceramic actuator [Kenji Uchino: Piezoelectric / electrostrictive actuator; Kyoritsu Shuppan] using a piezoelectric element in which piezoelectric element plates are laminated, but this has a simple polarization direction. If you try to stack a piezoelectric element plate that has a complicated structure in which the piezoelectric elements are simply stacked and divided into a number of electrodes and the polarization polarities alternate, the wiring for polarization processing and driving becomes complicated, It could not be realized.

[0006]

The structure for achieving the object of the present invention is to provide a laminated piezoelectric element in which a plurality of piezoelectric element plates each having an electrode formed on one side of a piezoelectric ceramic are laminated in the thickness direction. Wavelength (λ) in the circumferential direction due to expansion and contraction
, Two groups of a plurality of electrode portions that excite standing waves of one or a plurality of wave numbers are formed in the same phase in the thickness direction on one surface side of the piezoelectric ceramic, and in the circumferential direction an odd multiple of 1/4 A plurality of first piezoelectric element plates arranged at intervals,
An electrode portion is formed on one surface side of the piezoelectric ceramics over the front surface, and the piezoelectric ceramics has second piezoelectric element plates alternately laminated with the first piezoelectric element plates. ) Direction expansion and contraction in a plurality of layers can be simultaneously formed, and a conventional piezoelectric element capable of forming a traveling wave of one or a plurality of wave numbers in the circumferential direction by combining two standing waves to be excited. Compared with this, it is possible to obtain the same amplitude with a lower frequency applied voltage, and a booster circuit is unnecessary.

If an electrode portion is formed on the second piezoelectric element plate corresponding to the electrode portion of the first piezoelectric element plate and an intermediate voltage is applied to the electrode portion, a double electric field is generated. It is possible to supply the voltage, and it is possible to drive at a lower voltage.

On the other hand, it is possible to facilitate the formation of the electrode film by having an electrode-free portion in which no electrode portion is formed on one surface side of the first piezoelectric element plate, but it is possible to form a quarter wavelength. By forming the electrode portions over the entire surface at intervals of, the expansion and contraction energy can be taken out more.

On the other hand, the electrodes of the piezoelectric element plates to be laminated are electrically connected to corresponding electrode portions in the thickness direction every other layer by through holes, or to the uppermost piezoelectric element plate to be laminated,
By forming a plurality of electrode parts that are electrically connected to the lower layer electrode parts through through holes, the number of wiring lines during polarization and the number of power supply wiring lines from the drive circuit can be reduced, and furthermore, the uppermost piezoelectric element By using only the electrodes formed on the plate, it is possible to apply a frequency voltage for polarization processing and driving.

Then, by gathering one end sides of the plurality of electrode portions formed on the uppermost piezoelectric element plate at substantially one place,
The connection part of the flexible printed circuit board connected for power supply can be made smaller, the cost can be reduced and the vibration damping due to the board resin can be suppressed to a small level. The drive efficiency of the drive device can be improved.

Of course, since a sensor phase can be provided also in this laminated piezoelectric element, the drive control of the vibration wave drive device can be performed with high accuracy.

[0012]

1 is an exploded perspective view showing a first embodiment of a laminated piezoelectric element according to the present invention, and FIG. 2 is a plan view of electrodes formed on one side of piezoelectric ceramics constituting the laminated piezoelectric element of FIG. Indicates.

The laminated piezoelectric element of this embodiment is shown in FIG.
(F) is a laminated piezoelectric element plate made of six annular piezoelectric ceramics, and is divided into three types of elements by an electrode pattern formed on one side of these piezoelectric ceramics.

On the uppermost piezoelectric element plate 4 having the first electrode pattern, the GND electrode 14G for the ground (GND) is formed with a length of a quarter wavelength (λ) in the circumferential direction. On both sides of 14G, the A-phase power supply electrode 14A (1
4A (+), 14A (-), and B-phase power supply electrode 14B
(14B (+), 14B (-)) are formed, and the inner circumference side feeding electrodes 14A (-), 14B (-) are made shorter than the outer circumference side feeding electrodes 14A (+), 14B (+). That is, the portion of the A phase and the B phase, which are polarized in the (+) direction, is more G than the portion that is polarized in the (−) direction.
This is because it is provided at a position apart from the ND electrode 14G. Further, since one end side of each of these power supply electrodes is provided adjacent to the GND electrode 14G, as shown in FIG. 6, they are connected compactly by the flexible printed circuit board 30 connected to a drive circuit (not shown).

The piezoelectric element plate having the second electrode pattern is the second piezoelectric element plate 2 from the top, the fourth piezoelectric element plate 2 from the top as shown in FIGS. 2 (b), (d) and (f). The sixth (lowermost layer) piezoelectric element plate 3 and the GN of the uppermost piezoelectric element plate 4
When the D electrode 14G is used as a reference, the first electrodeless portion 15-1 in which no electrode having a length of 3/4 wavelength (λ) is provided with the center of the GND electrode 14G being the same as the circumferential center. Then, a second electrodeless portion 15-2 in which no electrode having a length of ¼ wavelength (λ) is formed is provided at a position symmetrical to the first electrodeless portion 15-1. The positive and negative electrodes 12 (13) A (+) and 12 (13) A (-) for the A phase and the positive and negative electrodes for the B phase with a length of a half wavelength between the two electrodeless portions. Electrodes 12 (13) B (+), 12 (13) B
(-) Is formed on both sides.

The difference between the second and fourth piezoelectric element plates 2 and the sixth (lowermost layer) piezoelectric element plate 3 is that the piezoelectric element plate 4 from the uppermost layer of the first layer to the piezoelectric element plate of the lowermost layer. Conductive holes 50 through which the electrodes and the conductive wires 42 to 45 come into contact with each other in the piezoelectric element plates of the second layer and the fourth layer arranged between 3 and conductive wires for conducting the first electrodeless portion. Only the conduction hole 50a through which 41 passes is formed, and other points have the same structure.

The piezoelectric element plate having the third electrode pattern is the third and fifth from the top shown in FIGS. 2 (c) and 2 (e).
In the th piezoelectric element plate 1, the GND electrode 11G is formed on the entire surface, the through hole 51 is formed in a non-contact state with the GND electrode 11G, and the conductive wires 42 to 45 penetrate therethrough, and the conductive wire 4
And a conductive hole 52 penetrating through so as to make contact with each other.

The six piezoelectric element plates 1, 2, 3 and 4 having the above-described structure are laminated in the phase of the arrangement shown in FIG. The conductive line 41 includes the first-layer GND electrode 14G and the third layer GND electrode 14G.
And the conductive wire 42 is electrically connected to the GND electrode 11G of the piezoelectric element plate 1 of the fifth layer, and the conductive wire 42 is the electrode 14B (−), 12B (−), 13B of the piezoelectric element plates 2 and 3 of the second, fourth and sixth layers.
Conductive (-), the conductive wire 43 is also the electrode 14B
(+), 12B (+), and 13B (+) are electrically connected, and the conductive line 44 has electrodes 14A (-), 12A (-), and 13A.
Conductive line (-), the conductive wire 45 is also the electrode 14B
It conducts to (+), 12B (+), and 13B (+).

In order to facilitate understanding, the conductive wire 41
It is supposed that the electrodes are electrically connected between the laminated piezoelectric element plates by .about.45, but this is actually done by through holes, which eliminates the work of connecting conductors every other layer, or the outer edge. The conductive paint is not applied to the parts to cause protrusions.

FIG. 3 is a schematic diagram showing a polarization treatment method for the laminated piezoelectric ceramics shown in FIG.

All the contact pins for the polarization treatment are brought into contact with the electrodes of the uppermost piezoelectric element plate 4, and the GND electrode 1
For 4G, positive electrodes 14A (+), B for A and B phases
(+) Is a positive voltage, A and B phase negative electrodes 14A (-),
A negative voltage is applied to B (-). Here, the whole surface electrode 11G of the piezoelectric element plate 1 of the third and fifth layers is polarized through a through hole (indicated by a lead wire 41 in FIG. 1) that is electrically connected to the GND electrode 14G of the piezoelectric element 4 of the uppermost layer. A voltage is applied, and the positive electrodes 12 (13) A of the second, fourth and sixth piezoelectric element plates 2 and 3 arranged so as to sandwich the piezoelectric element plates 1 of the third and fifth layers, B (+) is provided with a negative electrode 12 (13) through a through hole (indicated by conducting wires 43, 45 in FIG. 1) that is electrically connected to the electrodes 14A (+) and B (+) of the uppermost piezoelectric element plate 4. A and B (-) have through-holes (shown by conductors 42 and 44 in FIG. 1) that are electrically connected to the electrodes 14A (-) and B (-) of the uppermost piezoelectric element plate 4.
The above voltage for polarization processing is applied via.

FIG. 4 is a development view (developed at the center of the electrode 14G) showing the polarization state of the laminated piezoelectric element 10 subjected to the polarization treatment shown in FIG. 3, and the arrow indicates the polarization direction.

Here, the piezoelectric ceramics to be polarized are the piezoelectric ceramics of the second, third, fourth and fifth layers, and the positive electrode 12 (where a high potential voltage is applied to the GND electrode 11G). 13) Between A and B (+), GN
Negative electrode 1 that is polarized toward D electrode 11G
Between 2 (13) A and B (-), the polarization process is performed from the GND electrode 11G toward the negative electrodes 12 (13) A and B (-).

Therefore, if a positive voltage is applied between the positive power supply electrodes 14A, B (+) and the GND electrode 14G of the uppermost piezoelectric element plate 4 of the laminated piezoelectric element 10 polarized in this way, , Positive electrode 1 of the intermediate layer of piezoelectric ceramics
2 (13) A and B (+) are contracted in the thickness direction, so that the negative power supply electrodes 14A and B (−) and the GND electrode 14G.
If a negative voltage is applied between the positive electrode 12 and the positive electrode 12 (13) A, B (-) of the piezoelectric ceramic of the intermediate layer extends in the thickness direction, an AC voltage is applied to these feeding electrodes. Then, expansion and contraction are repeated and vibration is excited.

In FIG. 6, the laminated piezoelectric element 10 is fixed to the back surface side of the ring-shaped vibrating elastic body 20 with an adhesive agent.
The flexible substrate 30 for connection is adhered to the power supply electrode of the piezoelectric element plate 4 of the layer. This flexible substrate 30 is connected to a drive circuit (not shown), and the A-phase power supply electrode 1
4A (+) and (-) are connected to the A-phase power supply pattern 31A, B-phase power supply electrodes 14B (+) and (-) are connected to the B-phase power supply pattern 31B, and GND electrode 14G is connected to the GND. The power feeding pattern 31G is connected.

A terminal portion 32A on the other end side of the A-phase power feed pattern 31A and a terminal portion 3 on the other end side of the B-phase power feed pattern 31B.
When an AC voltage having a phase shift is input to the 2B from a drive circuit (not shown), the A phase and the B phase have a positional phase of 1/4, so that a traveling wave is generated by combining the standing waves of both phases. Are formed, and an elliptical motion is formed on the surface particles of the driving surface of the vibrating elastic body 20. Therefore, when the vibrator constituted by the laminated piezoelectric element 10 and the vibrating elastic body 20 is used as a stator, and a rotor (not shown) is brought into pressure contact with the driving surface of the vibrating elastic body 20, the ultrasonic wave for rotating the rotor is generated. It can be used as a motor,
Further, if a seed member such as paper is brought into pressure contact, it can be used as a sheet feeding device, and further, the laminated piezoelectric element and the vibrating elastic body 20 are formed into an elliptical shape, and a linear portion on one side thereof extends linearly. The present invention can be applied to various types of vibration wave drive devices in which a linear drive device can be utilized by making pressure contact with a stator (not shown).

In the polarization treatment method shown in FIG. 3 described above, separate contact pins are respectively brought into contact with the positive and negative electrodes of the A and B phases to apply the same potential voltage. However, as shown in FIG. 5, the positive power supply electrodes 14A (+) and 14B (+) of the uppermost piezoelectric element plate 4 are connected, and the negative power supply electrodes 14A (−) and 14B (−) are connected. If they are connected in advance, the number of contact pins can be reduced. And after the polarization process,
By cutting off the connecting portions 14C and 14D, the same laminated piezoelectric element as shown in FIG. 1 can be obtained.

The laminated piezoelectric element 10 shown in FIG.
Although the sensor phase for detecting the vibration state is not provided, as shown in FIG. 7B, the piezoelectric element plate 2 of the second layer is provided.
The sensor electrode 12S having a quarter wavelength width is provided in the first electrodeless portion 15-1 without contact with the conduction hole 50a, while the uppermost piezoelectric element plate 4 is electrically conducted with the sensor electrode 12S by a through hole or the like. The electrode 14S is formed.

Therefore, if a positive or negative voltage is applied to the electrode 14S during the polarization process, the polarization process for the sensor is performed with the electrode 11G of the piezoelectric element plate 1 of the third layer.
Note that, for example, if the power feeding electrode 14A
If it is connected to the (+) at the outer peripheral portion, no wiring for the sensor is particularly prepared for the polarization treatment.

The flexible printed circuit board 30 connected to a driving circuit for driving is, as shown in FIG.
The S-phase power feed pattern 31S is provided so as not to contact the GND power feed pattern 31G.

FIG. 9 shows a second embodiment of the present invention.

Similar to the case shown in FIG. 2, the laminated piezoelectric element of this embodiment is composed of six piezoelectric ceramics, and the different points are shown in FIGS. 9 (b), 9 (d) and 9 (f). , Second,
Electrodes are formed on the entire circumference of the piezoelectric element plates of the fourth and sixth layers at intervals of a quarter wavelength, and the positive electrode of phase A 12 (1
3) By arranging A (+) and the negative electrode 12 (13) A (−), and the B-phase positive electrode 12 (13) B (+) and the negative electrode 12 (13) B (−) at every other pole, Phase A and Phase B are 4 overall
One-half wavelength spacing is obtained.

Therefore, since the piezoelectric ceramics can be used over the entire circumference, the same output can be obtained at a lower voltage as compared with the first embodiment described above.

In the present embodiment, the above-mentioned second and fourth
Also, since the A-phase and B-phase electrodes are arranged alternately around the entire circumference of the sixth piezoelectric element plates 2 and 3, the piezoelectric element plate of the first layer arranged in the uppermost layer for polarization processing and power feeding. The power supply electrodes formed in 4 are arranged in four inner and outer circumferential directions,
Similar to the first embodiment, each of the through holes of the piezoelectric element plates of the second and lower layers can be connected.

In addition, these power supply electrodes 14A (+),
One ends of (−), 14B (+), and (−) are arranged close to the GND electrode 14G to facilitate collective connection with the flexible printed circuit board as in the first embodiment.

As shown in FIG. 7, an electrode for detecting the vibration state may be provided on a part of the second layer piezoelectric element plate.

FIG. 10 shows a third embodiment of the present invention.

In this embodiment, (b), (d) of FIG.
As shown in (f), the second embodiment shown in FIG. 9 is that electrodes are formed on the entire circumference of the piezoelectric element plates 2 and 3 of the second, fourth and sixth layers at intervals of a quarter wavelength. Similar to the example, but with the third and fifth layer piezoelectric element plates 6 shown in (c) and (e) of FIG.
The GND electrode 16A in the same phase as the A-phase and B-phase electrodes of the piezoelectric element plates 2 and 3 arranged above and below.
And 16B are alternately formed at quarter wavelength intervals. Further, electrodes for polarization and power feeding are concentrically formed on the piezoelectric element plate 4 of the uppermost first layer for six rounds, and the two power feeding electrodes 14AG and 14BG on the inner circumferential side are provided in each of the above-described embodiments. As in the example, the through holes allow the electrodes of the piezoelectric element plates 6 of the third and fifth layers, specifically, the feeding electrode 14AG to be A.
The phase GND electrode 16A and the power supply electrode 14BG are connected to the B phase GND electrode 16B. In addition, the power supply electrodes 14A (+), (-), 14B (+),
(−) Indicates the electrodes 12 (13) A (+), (−), 12 of the same phase and the same polarity of the piezoelectric element plates 2 and 3 of the second, fourth and sixth layers.
(13) B (+) and (-) are similarly connected by through holes.

The polarization treatment method for the laminated piezoelectric element having the above-described structure is substantially the same as that of the first embodiment described above, except that the power supply electrodes for GND are 14AG and 14BG.
It is divided into two, and by supplying an intermediate potential to the power supply electrodes 14AG and 14BG for both GNDs, each GND of the piezoelectric element plates 6 of the third and fifth layers is supplied.
The intermediate potential is applied to the electrodes 16A and 16B.

The power supply electrodes 14A (+), 14B
A positive voltage is applied to (+) and the power supply electrodes 14A (-), 14
When a negative voltage is supplied to B (-) from a drive circuit (not shown), positive and negative voltages are applied to the positive and negative electrodes of the second, fourth and sixth piezoelectric element plates 2 and 3, respectively, and this polarization is applied. The state is shown in FIG.

As shown in FIG. 12, in the flexible substrate 30 connected to the power supply electrode of this laminated piezoelectric element, the power supply pattern 31A ¹ is connected to the GND electrode 14AG, and the power supply pattern 31B ¹ is connected to the GND electrode 14BG. And both of these feeding patterns 31A ¹ ,
A drive voltage is supplied to 31B ¹ from a drive circuit (not shown) via terminal portions 32A ¹ and 32B ¹ as follows.

That is, the feeding electrodes 14A (+), (-)
Terminal portion 32A electrically connected to the power supply electrode 14B (+),
The phase difference of the drive frequency voltage supplied to the terminal portion 32B that conducts to (-) is +90 deg or -90 deg, but the drive is supplied between the terminal portions 32A and 32A ¹ and between the terminal portions 32B and 32B ¹ , respectively. Frequency voltage phase difference is 1
It becomes 80 deg. Therefore, the second, third, fourth and fifth layers of the piezoelectric ceramics sandwiched between the GND electrodes 16A, B and the electrodes 12 (13) A, B (+), (-) are
The voltage is twice as high as that in the above-described first and second embodiments. Therefore, even lower voltage driving is possible.

In order to reduce the number of wiring lines during polarization processing, as in the first and second embodiments, 14A (+) is not used for the piezoelectric element plate 4 of the first layer at an unused portion. And 14B
(+), 14A (-) and 14B (-), 14AG and 14
It is also possible to connect BG and cut or cut off these connection parts after polarization processing. Further, similarly to the second embodiment, electrodes for detecting a vibration state may be provided in the first layer and the second layer.

FIG. 13 shows a lens barrel having an ultrasonic motor using the laminated piezoelectric element in each of the above embodiments as a drive source.

Reference numeral 100 denotes a vibrator in which the laminated piezoelectric element 10 is bonded to the elastic body 20 shown in FIG. 6, for example, which abuts the stopper member 102 via the pressure spring 101 and has an annular shape on the drive surface side. The output member 103, which is a rotor, is in pressure contact with the friction member 104. Reference numeral 105 denotes a roller connected to the focus key 106, which moves the focus lens L in the optical axis direction by rotating around the optical axis.
This roller 105 is an output member 103 from the ultrasonic motor.
And the manual focus ring 107 that moves in the direction of the optical axis to switch between manual focus and auto focus, is in frictional contact with the manual output ring 108 that rotates around the optical axis, and the manual focus ring 107 has the manual output ring. In the case of a non-coupled autofocus state with 108, the rotation of the output member 103 causes differential rotation to drive the focus key 106 to rotate,
The focus lens L is driven by the ultrasonic motor for focusing. When the manual focus ring 107 is connected to the manual output ring 108, rotating the manual focus ring 107 causes the roller 1 to rotate.
Similarly, the focus lens L is moved by the focus key 106 by the differential rotation of 05,
Manual focus is performed.

In each of the above-mentioned embodiments, the laminated piezoelectric element is formed by laminating six piezoelectric ceramics, but the invention is not limited to this, and the laminated piezoelectric element is formed on the piezoelectric element plate arranged in the intermediate layer. The number of electrodes may be set according to the required number of traveling waves.

[0047]

As described above, the laminated piezoelectric element of the present invention can form a traveling wave by combining standing waves of one or a plurality of wave numbers, and is required for polarization processing and power supply for driving. Wiring can be reduced.

Further, the electrodes are connected between the respective layers by through holes, which eliminates the need for the work of connecting the conductive wires for every other layer, or the conductive coating is applied to the outer edges to form the protrusions. There is no such thing.

Furthermore, since power supply for polarization processing and driving can be performed only by the electrodes provided on the uppermost piezoelectric element plate, it is possible to reduce wiring for polarization processing and power supply wiring for driving. Become.

On the other hand, in connection with the drive circuit, since the electrodes for power supply are concentrated in one place, the area of the connection portion of the flexible board for connection can be reduced, and the cost can be reduced. Vibration damping due to the substrate resin can be suppressed to a small level, and the driving efficiency of a vibration wave driving device such as a vibration wave motor using this piezoelectric element can be improved.

Of course, since the sensor phase can be provided also in this laminated piezoelectric element, the drive control of the vibration wave drive device can be performed with high accuracy.

Further, since no electrode is provided on the outer surface of the lowermost layer of the laminated piezoelectric element, when the laminated piezoelectric element is bonded to the vibrating elastic body, for example, the piezoelectric element plate of the lowermost layer is bonded to the elastic body with an adhesive. It is only necessary to adhere them, and it is not necessary to apply a conductive paint to the side surface of the piezoelectric ceramic in order to easily connect the whole surface electrode provided on the joint surface side to the GND side of the drive circuit as in the conventional case.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a laminated piezoelectric element showing a first embodiment of the present invention.

FIG. 2 is a plan view showing electrodes of each piezoelectric element plate constituting the laminated piezoelectric element of FIG.

FIG. 3 is a perspective view showing a polarization treatment method for the laminated piezoelectric element shown in FIG.

FIG. 4 is a development view showing polarization directions of the laminated piezoelectric element of FIG.

5 is a plan view of the electrodes of the uppermost piezoelectric element plate showing a modification of the embodiment of FIG.

6 is an exploded perspective view of a vibrator of an ultrasonic motor using the laminated piezoelectric element shown in FIG.

FIG. 7 is a plan view showing electrodes of each piezoelectric element plate, which is a modification of the embodiment shown in FIG.

8 is a plan view of a flexible substrate for connection used in the laminated piezoelectric element of FIG.

FIG. 9 is a plan view showing electrodes of each piezoelectric element plate constituting the laminated piezoelectric element of the second embodiment.

FIG. 10 is a plan view showing electrodes of each piezoelectric element plate that constitutes the laminated piezoelectric element of the third embodiment.

11 is a development view showing polarization directions of the laminated piezoelectric element of FIG.

12 is a plan view of a flexible board for connection used in the laminated piezoelectric element of FIG.

FIG. 13 is a cross-sectional view of a lens barrel that uses an ultrasonic motor that uses the laminated piezoelectric element according to any of the first to third embodiments as a drive source.

[Explanation of symbols]

 1, 2, 3, 4 Piezoelectric element plate 10 Laminated piezoelectric element 20 Vibration elastic body 30 Flexible substrate

Claims (10)

[Claims] 1. A laminated piezoelectric element in which a plurality of piezoelectric element plates each having an electrode formed on one surface side of a piezoelectric ceramic are laminated in the thickness direction, wherein expansion or contraction in the thickness direction results in one or a plurality of wave numbers at a wavelength (λ) in the circumferential direction. A plurality of two groups of electrode portions for exciting standing waves are formed on one side of the piezoelectric ceramic in the same phase in the thickness direction and arranged at intervals of an odd multiple of a quarter wavelength in the circumferential direction. A plurality of first piezoelectric element plates, and a second piezoelectric element plate in which an electrode portion is formed over the entire surface on one side of the piezoelectric ceramics and which is alternately laminated with the first piezoelectric element plates. A laminated piezoelectric element characterized by: 2. A laminated piezoelectric element in which a plurality of piezoelectric element plates each having an electrode formed on one side of a piezoelectric ceramic are laminated in the thickness direction, wherein expansion or contraction in the thickness direction results in one or more wavenumbers at a wavelength (λ) in the circumferential direction. A plurality of two groups of electrode portions for exciting standing waves are formed on one side of the piezoelectric ceramic in the same phase in the thickness direction and arranged at intervals of an odd multiple of a quarter wavelength in the circumferential direction. A plurality of first piezoelectric element plates, and electrode portions are formed on one side of the piezoelectric ceramics so as to correspond to the electrode portions of the first piezoelectric element plate, and the first piezoelectric element plates are alternately laminated and arranged. A laminated piezoelectric element. 3. The laminated piezoelectric element according to claim 1, wherein the first piezoelectric element plate has an electrode-free portion in which an electrode portion is not formed, on one surface side thereof. 4. The laminated piezoelectric element according to claim 1, wherein electrode portions are formed on the entire surface of one surface of the first piezoelectric element plate at intervals of a quarter wavelength. 5. The electrode according to claim 1, 2, 3, or 4, wherein the electrodes of the laminated piezoelectric element plates are electrically connected to corresponding electrode portions in the thickness direction by through holes. And a laminated piezoelectric element. 6. The method according to claim 1, 2, 3, 4 or 5.
A laminated piezoelectric element characterized in that a plurality of electrode portions electrically connected to the lower layer electrode portions through through holes are formed on the laminated uppermost piezoelectric element plate. 7. The laminated piezoelectric element according to claim 6, wherein one end sides of the plurality of electrode portions formed on the piezoelectric element plate of the uppermost layer are provided so as to be gathered at substantially one place. 8. The method according to claim 1, wherein
A laminated piezoelectric element characterized in that a part of one of the piezoelectric ceramic layers is used as a sensor phase, and an electrode for extracting a signal of the sensor phase is provided on the uppermost piezoelectric element plate. 9. The laminated piezoelectric element according to any one of claims 1 to 8 is bonded to a vibrating elastic body, and alternating voltages having different phases are applied to the laminated two groups of electrode portions, and the elastic vibrating body is applied to the vibrating elastic body. An oscillating wave driving device, characterized in that surface particles of the oscillating elastic body are excited by an elliptic motion by synthesizing two formed standing waves. 10. An apparatus using the vibration wave drive apparatus according to claim 10 as a drive source.