JP2002353530A - Laminated electromechanical energy conversion element and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated piezoelectric element using a through-hole capable of miniaturizing an oscillatory wave motor. SOLUTION: The laminated piezoelectric element is provided, where a plurality of electrode regions 4 and 5 of a plurality of piezoelectric layers 2 and 3 are connected using a through-hole 6; the through-hole 6 is formed into a semicircle so as to be exposed to the outside diameter part, so that the area of an insulation part around the through-hole 6 is reduced to be as small as possible, resulting in an enlarged area of effective piezoelectric active part of the laminated piezoelectric element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated electro-mechanical energy conversion element such as a piezoelectric element and a method of manufacturing the laminated electro-mechanical energy conversion element, and more particularly to a laminated electro-mechanical energy conversion element. And a through hole for connection between layers.

[0002]

2. Description of the Related Art Conventionally, piezoelectric materials having an electric-mechanical energy conversion function have been used in a wide variety of piezoelectric elements and piezoelectric devices. Above all, as a recent trend,
These piezoelectric elements and piezoelectric devices are not used in a single plate shape but in a thin sheet shape in which a large number of piezoelectric elements and piezoelectric devices are stacked.

[0003] This is largely due to the fact that a large deformation strain and a large force can be obtained with a low applied voltage by lamination as compared with a single plate-shaped piezoelectric element. Further, sheet molding and lamination manufacturing methods have become widespread, and the thickness of each layer has been reduced, so that small-sized, high-performance laminated piezoelectric elements and piezoelectric devices can be easily manufactured. is there.

For example, a laminated piezoelectric element for a vibration wave motor, which is one example of a vibration wave driving device, is disclosed in JP-A-6-77.
550, JP-A-6-120580, JP-A-8-213664 and the like have been proposed. Also. As other examples, many laminated piezoelectric elements for a vibrating gyroscope and a piezoelectric transformer have been proposed.

[0005] The laminated electro-mechanical energy conversion element used for such various uses has a structure in which a plurality of layered materials having an electro-mechanical energy conversion function in which an electrode region is formed are stacked. That is, as a typical example, a piezoelectric ceramic layer (hereinafter, referred to as an internal electrode) provided on the surface of an electrode layer formed of an electrode material (hereinafter, referred to as an internal electrode) is provided.
(Called a piezoelectric layer).

Recently, as an interlayer wiring for connecting a plurality of laminated internal electrodes, a through hole (or a via hole) in which a hole is formed in a layer of a piezoelectric layer and an electrode material is embedded is provided. For example, for example, see JP-A-6-12058.
No. 0, JP-A-8-213664 and the like have become more common. Note that Japanese Patent Laid-Open No. 6-
Japanese Patent Application Laid-Open No. 77550 discloses an example in which an external electrode as an interlayer wiring is used outside.

This is because the reliability of the electrical connection has been improved by improving the precision of the positioning of the through hole due to the improvement of the manufacturing apparatus and the manufacturing technology, and further, by using the through hole. This is because there are advantages such as downsizing of the element.

FIG. 8 shows a conventional laminated piezoelectric element described in Japanese Patent Application Laid-Open No. Hei 8-213664. The laminated piezoelectric element 31 has a through hole 1 for connecting internal electrodes.
As shown in FIG. 9, it is incorporated in a vibration wave motor 40 and has already been put to practical use, for example, as an autofocus motor for a camera lens.

In FIG. 8, in a disc-shaped laminated piezoelectric element 31 having a through hole formed in the center, a through hole 36 indicated by a black circle is formed on the inner diameter side so as to obtain conduction between the laminated piezoelectric layers. It was made. On the surfaces of the two types of piezoelectric layers 32 and 33 constituting the laminated piezoelectric element 31, four divided internal electrodes (electrode patterns) 34 (34-1, 34-2,
34-3, 34-4) and 35 (35-1, 35-2,
35-3, 35-4) are provided. The first and lower surface layers are the piezoelectric layers 3 from the second layer to the twenty-fifth layer.
2 and 33 are arranged alternately. A through hole 36 indicated by a black circle in the figure is formed on the inner diameter side of each piezoelectric layer, and four divided electrode portions 34 (34-1, 34-1) of each internal electrode 34 in each of the piezoelectric layers 32 stacked alternately. 34-2, 3
4-3, 34-4) are provided in the electrode portion so as to conduct in the direction in which they overlap.

Similarly, in each of the other piezoelectric layers 33, the four divided electrode portions 3 of the internal electrodes 35 are similarly formed.
Four through holes are further provided in the electrode portion so as to conduct in the direction in which 5 (35-1, 35-2, 35-3, 35-4) are overlapped. However, since the 25th layer has no layer below it, no through hole is provided.

The eight through holes 36 are independent of each other and are non-conductive, and the surface electrodes 37 are formed by exposing the ends of the through holes 36 on the surface of the laminated piezoelectric element 31. Further, each of the internal electrodes 34 and 35 is not formed up to the outer diameter and inner diameter edges, and there is a non-electrode region at the outer diameter and inner diameter edges.

The thus constituted laminated piezoelectric element 31 shown in FIG. 8 is subjected to the following polarization treatment so as to generate vibration suitable for a vibration wave motor as a vibration wave driving device. .

In the laminated piezoelectric element 31, the internal electrode 35 of each piezoelectric layer 33 inside the element is divided into four divided electrode portions 35.
(35-1, 35-2, 35-3, 35-4), and the electrode portions 35-1, 35-
3 and two electrode portions 35-2 and 35-4 are polarized to + (plus) and-(minus) so that the polarization polarities are different from each other.

That is, as shown in FIG.
-1, 35-3 are A +, A? , Electrode portions 35-2, 35-
4 is B +, B? The A-phase and the B-phase, respectively, and the four divided electrode portions 34 (34-1, 34-2, 34-3, 34-4) of the internal electrode 34 of the piezoelectric layer 32 facing them are also 180 degrees. Electrode portions 34-1 and 34-3 at positions
And two of the electrode portions 34-2 and 34-4 are set to an AG phase and a BG phase, and are electrically grounded.

FIG. 9 is a sectional view of a rod-shaped vibration wave motor 40 as a vibration wave driving device in which the laminated piezoelectric element 31 is incorporated in a vibration body 41. The laminated piezoelectric element 31 includes a vibrating body 41
Are in direct contact with the wiring board 38 connected to an external power supply and are clamped by bolts 44 between the metal parts 42 and 43 which are elastic bodies. Then, the eight surface electrodes 37 of the laminated piezoelectric element 31 and the electrode patterns of the wiring board 38 are electrically connected.

The driving principle of the rod-shaped vibrating wave motor 40 is as follows. Two orthogonal bending vibrations are generated in the vibrating body 41 in which the laminated piezoelectric element 31 is incorporated, and the rotor 47 is brought into pressure contact with the bending vibrations.
Is driven by a frictional force.

That is, the AG phase opposed to the A phase and the B phase,
The BG phase is set to the ground, and a high-frequency voltage substantially equal to the natural frequency of the vibrating body is applied to the A phase. Further, the B phase, which differs from the A phase by 90 degrees in the spatial phase position, is electrically shifted by 90 degrees from the A phase. And applying a high-frequency voltage having the same frequency but different
A driving vibration is obtained by synthesizing two bending vibrations generated in (1).

The rotor 47, which comes into pressure contact with one surface of the metal component 42 via a spring 45 and a spring support 46, is frictionally driven by the drive vibration generated in the vibrator 41,
Gear 48 as an output member that rotates integrally with the rotor 47
Outputs a driving force.

[0019]

However, when a conventional vibration wave motor was examined in order to develop a more compact vibration wave motor, it was found that the laminated piezoelectric element had the following problems. Have been.

In a laminated piezoelectric element using a through-hole, an insulating portion (around the through-hole) is provided around the through-hole in order to make the through-hole and the electrode portion of another internal electrode that is basically not conductive from the through-hole. In FIG. 8, the non-electrode forming portion 3
9 areas).

When the outer diameter of the laminated piezoelectric element is reduced while the through hole is formed on the inner diameter side as in the conventional electrode configuration shown in FIG. 8, a circular insulating material is formed around the through hole. Therefore, the area of the piezoelectric active portion (the portion between the internal electrodes 34 and 35) required for driving the vibration wave motor cannot be made sufficiently large. In this case, it was found that the performance of the small vibration wave motor could hardly be expected.

It is an object of the present invention to provide a laminated electro-mechanical energy conversion element and a method of manufacturing the same which are effective for improving the performance of a further small vibration wave motor.

[0023]

According to a first aspect of the present invention, a plurality of layers having a plurality of electrode regions and having an electromechanical energy conversion function are stacked, and a through hole is formed between each of the plurality of electrode regions. Stacked electricity connected using? In the mechanical energy conversion element, at least a plurality of the through holes are formed in an outer diameter or an inner diameter, or an outer diameter and an inner diameter, and the filler filled in the through hole faces an end surface of the outer diameter or the inner diameter. I do.

In a second aspect based on the first aspect, the through hole is formed in a substantially elliptical shape.

According to a third aspect of the present invention, in any one of the above-described aspects, conduction from the outside can be achieved from an end face of a through hole formed in the outer diameter portion or the inner diameter portion.

According to a fourth aspect of the present invention, in any one of the above aspects, the insulating portion around the through hole is formed substantially concentrically around the through hole at the outer or inner diameter portion of the laminated electro-mechanical energy conversion element. The feature is that.

According to a fifth aspect of the present invention, in any one of the above-mentioned inventions, each of the plurality of electrode regions in the plurality of layers excluding a through hole and an insulating portion around the through hole extends to an outer or inner edge of the laminated piezoelectric element. It is characterized by reaching.

According to a sixth aspect, in the fourth aspect, the through hole is not formed in the uppermost layer and the lowermost layer.

According to a seventh aspect of the present invention, in the first or second aspect, the through hole in one or more layers facing the end face of the outer diameter portion is used as a mark. Thus, it is possible to identify the element and determine the position of the element in the circumferential direction.

According to an eighth aspect of the present invention, a green sheet having a size larger than the outer diameter of the finished product in which the internal electrodes are formed on one surface is overlapped to form a through-hole substantially at the center of the outer or inner diameter of the finished product. A laminated body obtained by filling the through hole with a filler to form a laminated body, firing the laminated body, and machining the outer diameter portion to obtain a predetermined outer diameter. This is a method for manufacturing a mechanical energy conversion element.

According to a ninth aspect of the present invention, a green sheet having a size larger than the outer diameter of a finished product having an internal electrode formed on one surface is overlapped, and two green sheets having portions slightly overlapping substantially at the outer diameter position of the finished product are provided. The through-holes are formed substantially in the radial direction, and a laminate obtained by filling the through-holes with a filler is formed into a laminate, and after firing the laminate, the outer diameter portion is machined to obtain a predetermined outer diameter. And a method for manufacturing a laminated electro-mechanical energy conversion element.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a first embodiment of the present invention. The laminated piezoelectric element 1 as the laminated electro-mechanical energy conversion element of the present embodiment includes:
The through hole formed in the center portion is used as the inner diameter portion, and conduction between the stacked piezoelectric layers is obtained by using the through hole. The diameter of the laminated piezoelectric element 1 is smaller than that of the conventional example, as described later.

As shown in FIG. 1, slits (not-electrode-forming portions) formed in a cross shape with the diameter portions orthogonal to each other are formed on the surfaces of the two types of piezoelectric layers 2 and 3 constituting the laminated piezoelectric element 1. ), The internal electrodes 4 and 5 are connected to the electrode portions 4-1 and 4-
2,4-3,4-4 and the electrode parts 5-1,5-2,5-3,
The piezoelectric layers 2 and 3 are alternately arranged from the second layer to the 25th layer in every other layer below the first layer which is the surface layer (uppermost layer). Each internal electrode reaches the outer and inner edges of the disk-shaped piezoelectric body constituting each layer.

The outer diameter end of each piezoelectric layer is indicated by a black circle 4 in the figure.
The individual through holes 6 are formed. That is, each of the electrode portions 4-1 4-2, 4-3, and 4-4, which are divided into four of the internal electrodes 4 of the piezoelectric layers 2 of every other layer, are electrically connected to each other in a stacked state. Four through holes 6 were provided.

The electrode portions 5-1, 5-2, 5-3, and 5- are divided into four internal electrodes 5 of each of the other piezoelectric layers 3 disposed between the piezoelectric layers 2. Four more through-holes 6 were provided so as to conduct when the four were superposed. However, since only the 25th layer does not need to be electrically connected to the layer below it, no through hole is provided. These eight through holes 6 are independent of each other and are non-conductive.

Each of the eight through holes 6 exposes an end of the through hole 6 on the surface of the laminated piezoelectric element 1 to form eight surface electrodes 7 having the same size as the diameter of the through hole.

After the above configuration, polarization processing was performed in the same manner as in the following conventional example to give a polarization polarity suitable for the vibration wave motor. That is, in the laminated piezoelectric element 1, the four divided electrode portions 5-1, 5-2, 5-3 and 5-4 of the internal electrode 5 of the internal piezoelectric layer 3 are connected to the electrode portions having a positional relationship of 180 degrees. The two electrode portions 5-1 and 5-3 and 5-2 and 5-4 were polarized so that the polarization polarities were different from each other to + (plus) and-(minus).

That is, as shown in FIG.
1, 5-3 are A +, A- and 5-2, 5-4 are B +, B
? , And A and B phases, respectively. Then, the four divided electrode portions 4 of the internal electrodes 4 of the piezoelectric layer 2 facing these are formed.
1, 4-2, 4-3, and 4-4 are also connected to the electrode units 4-1 and 4-3 and 4-2 and 4-4 at the positions of 180 degrees, respectively.
And BG phases, and electrically grounded.

FIG. 3 is a view in which the laminated piezoelectric element 1 is incorporated in a vibrating body 21 constituting a rod-shaped small vibrating wave motor 20, which is substantially the same in structure as the conventional one, but has a small diameter.

The laminated piezoelectric element 1 was fastened by metal parts 22 and 23 which are elastic bodies of the vibrating body 21 and bolts 24 so that the wiring board 8 was in close mechanical contact with the laminated piezoelectric element 1.

The wiring substrate 8 is provided with wiring electrode patterns, and is electrically connected to each surface electrode 7 of the laminated piezoelectric element 1 so as to be connected to an external power supply. Wiring board 8
Is obtained by patterning a commonly used 25 .mu.m thick polyimide sheet on a 35 .mu.m thick copper foil for wiring.

Then, similarly to the conventional example, a high frequency voltage substantially matching the natural frequency of the vibrating body is applied to the A phase with the AG phase and the BG phase facing the A phase and the B phase as grounds.
Further, the A phase is shifted to the B phase having a spatial phase position different by 90 degrees from the A phase.
A high frequency voltage having the same frequency, which is electrically different from the phase by 90 degrees, was applied. In this manner, the rotor 27 which has come into pressure contact with one surface of the elastic member 22 through the spring 30 and the spring support member 31 by the driving vibration obtained by combining the two bending vibrations of the vibrating member 21 rubs. The driving force is output by a gear 28 as an output member which is driven by force and rotates integrally with the rotor 27.

Specifically, the laminated piezoelectric element of the present embodiment has an outer diameter of 6 mm, an inner diameter of 1.7 mm, a thickness of about 1.6 mm,
The thickness of the piezoelectric layer is about 60 μm, and the thickness of the internal electrode is 2 to 3 μm.
m, the total number of piezoelectric layers was 25, and the internal electrodes were 24. The diameter of the through hole is 0.35 mm. The outer diameter of the metal parts 22 and 23 which are elastic bodies is the same 6 mm.
It is.

The above-described conventional laminated piezoelectric element has an outer diameter of 10 mm.
mm, the inner diameter was 2.8 mm, the thickness was about 2.3 mm, the thickness of the piezoelectric layer was about 90 μm, the thickness of the internal electrode was 2 to 3 μm, and the total number of piezoelectric layers was 25.

The laminated piezoelectric element of the present embodiment has a smaller outer diameter and a smaller thickness per layer than the conventional example.

The method for manufacturing the laminated piezoelectric element of the present embodiment is as follows.
Piezoelectric ceramic powder and organic binder for the piezoelectric layer
First, a hole for making a through-hole was made on a grease sheet made of silver and palladium powder.
The paste was filled, and then a silver / palladium paste serving as an internal electrode was formed by screen printing. Then, the inner diameter was opened by machining before firing. Then, in a lead atmosphere, about 1100
After sintering at ℃, after sintering, polarization, double-sided lapping was performed, and finally the outer diameter portion was processed by mechanical (grinding) processing to produce.

A plurality of green sheets to be used as the piezoelectric layer are obtained from a single large sheet. Later, the outer part is machined into a circular shape. Therefore, in the finished product of the laminated piezoelectric element 1, the through hole 6 is formed in a semicircular shape at the outer end of the piezoelectric layers 2 and 3, but the state before firing of the through hole 6 is shown in FIG. As shown in the figure, a circle (shown as 0.35 m in diameter before firing)
m), and finally, the outer diameter is formed into a circular shape by machining, whereby the through hole 6 is formed in a substantially semicircular shape indicated by double oblique lines.

In this embodiment, a through hole is formed aiming at the outer diameter. At present, the positional accuracy with respect to the outside diameter of the through hole in manufacturing is
0.1mm, the diameter of the through hole is slightly increased to 0.35mm so that the charged material in the through hole is not scraped off
And

The radius of the approximately 1/4 circular insulating portion around the through hole is approximately equal to the radius of the through hole on the outer diameter.
0.6 mm. By the way, the slit separating the electrode layers is about 0.4 mm.

These values are dimensions that ensure insulation during use, and are values determined in consideration of the positional deviation of each electrode portion and through hole in the production of the laminated piezoelectric element, the use conditions, and the like. In the future, we want to make it even smaller by improving manufacturing technology.

As described above, in the laminated piezoelectric element 1 according to the present embodiment, the through hole 6 and the surface electrode 7 are formed at the outer diameter end of the element, and the area of the insulating portion formed around the through hole is substantially reduced. It has been reduced to half. Further, the internal electrode extends a region (hatched region in FIG. 1) to the outer diameter and the inner diameter end.

As a result, the performance (rotational speed and torque) and efficiency of the vibration wave motor could be improved as expected.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
An embodiment will be described.

The laminated piezoelectric element 11 of this embodiment has through holes formed in the inner diameter and the outer diameter, respectively.
Other modes, driving methods, manufacturing methods, and the like are all the same as those of the first embodiment.

As shown in FIG. 2, the internal electrodes 14 and 15 are divided into four on the surfaces of the two types of piezoelectric layers 12 and 13 constituting the laminated piezoelectric element 11 through slits (non-electrode forming portions). The piezoelectric layers 12 and 13 are alternately arranged every other layer from the first layer. The internal electrode has reached the outer diameter end and the inner diameter end.

At the outer diameter end and inner diameter end of each piezoelectric layer, through holes 16 indicated by black circles in the figure are formed, and the through holes 16 formed at the outer ends are the same as those in the first embodiment. The through hole 16 formed at the inner diameter end is formed in the same manner as the through hole formed at the outer end.

FIG. 3 is a diagram in which the laminated piezoelectric element 11 is incorporated in a vibrating body 21 constituting a rod-shaped vibrating wave motor 20. The laminated piezoelectric element 11 sandwiches the wiring board 18 and
The first metal parts 22 and 23 are in full contact with each other and are fastened by bolts 23.

The laminated piezoelectric element of the present embodiment differs from the laminated piezoelectric element of the first embodiment in that the laminated piezoelectric element also has a through hole in the inner diameter. This is because, by dispersing a plurality of through-holes on the outer diameter side and the inner diameter side, the wiring electrode pattern on the wiring board 18 can have a sufficient space and the design is simplified. . In developing a small vibration wave motor, this has a great practical effect.

As a result, the performance (rotational speed and torque) of the small vibration wave motor and the motor efficiency were improved.

In the embodiment shown in FIG. 2, through holes having a substantially semicircular shape are formed at the inner diameter end and the outer diameter end, however, all through holes may be provided at the inner diameter end. However, as described above, the area around the inner diameter due to the reduction in diameter becomes considerably small, and the design of the electrode pattern for wiring of the wiring board becomes considerably troublesome. Therefore, it is preferable to disperse the through holes in the outer diameter or the outer diameter and the inner diameter.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
An embodiment will be described.

As shown in FIG. 4, the laminated piezoelectric element 10 according to the first embodiment shown in FIG. 1 has the same structure as that of the first embodiment shown in FIG. Similarly to the above, the piezoelectric layers 2 and 3 are alternately arranged from the second layer to the 25th layer every other layer below the first layer.
However, the 25th layer is the final layer, and there is no need to conduct electricity to the layer below it, so that no through hole is provided.

In the laminated piezoelectric element 10, the cross section of the through hole is exposed on the outer peripheral surface other than the first and 25th layers. All other forms, driving methods, manufacturing methods, etc. are the first
This is the same as the embodiment.

FIG. 5 is a view in which the laminated piezoelectric element 10 shown in FIG. 4 is incorporated in a vibrating body 21 'constituting a rod-shaped vibrating wave motor 20'. The laminated piezoelectric element 10 is an elastic body of the vibrating body 20 '. Contact with the metal parts 22 and 23 which are
Is tightened.

Since the cross-section of the through-hole 6 is linearly exposed at the outer peripheral portion of the laminated piezoelectric element 10, unlike FIG. 3, a wiring board 19 is wound around and the exposed through-hole is connected to the outside. Is conducted. Wiring board 19
The electrode patterns are connected so as to drive the vibration wave motor with the cross section of each of the eight through holes.

When the wiring board 8 is sandwiched between the elastic metal component and the laminated piezoelectric element as in the first embodiment, the wiring board is made of a normal polyimide resin, so that the vibration attenuation is large. However, the performance and efficiency of the vibration wave motor deteriorate. In particular, such a small vibration wave motor has a great influence of such a slight vibration damping. Therefore, the method of not sandwiching the wiring board as in the present embodiment is very useful for the small vibration wave motor. .

As described above, this embodiment is highly effective for improving the performance of a small vibration wave motor.

Here, when establishing conduction with the wiring board, it is not necessary to expose the through-holes exposed in all layers of the laminated piezoelectric element, and conduction can be achieved even with a cross section of only one layer of through-holes. Further, the position of the layer of the through hole to be exposed may be different for each through hole. These are very convenient in designing the electrode pattern of the wiring board.

However, it should be noted that if the number of layers having no through holes in the outer diameter increases, the area of the internal electrodes, which are the piezoelectric active portions of the original laminated piezoelectric element, decreases, and the performance of the motor decreases. is there.

(Fourth Embodiment) FIG. 6 shows a fourth embodiment of the present invention.
An embodiment will be described.

The laminated piezoelectric element 1 'of this embodiment is the same in appearance as the laminated piezoelectric element 1 of the first embodiment of the present invention. As shown in FIG. 6, the laminated piezoelectric element 1 '
The piezoelectric layers 2 'and 3' are alternately arranged from the second layer to the twenty-fifth layer every other layer below the first layer, similarly to the laminated piezoelectric element 1 of the first embodiment.

However, the shape of the through hole is different from that of the first embodiment. As shown in FIG. 7A, the through-hole 6 of the laminated piezoelectric element 1 according to the first embodiment had a circular shape with a diameter of 0.35 mm as shown in FIG. However, when the diameter of the through-hole is about 0.35 mm or more, the number of electrode materials to be filled in the through-hole is increased in manufacturing, so that the cost is increased, and cracks tend to occur easily.

Therefore, in the present embodiment, as shown in FIG. 7B, two through holes having a small diameter are formed side by side so as to have a portion slightly overlapping in the radial direction of the laminated piezoelectric element. The overlapping portion is a portion where the through-holes 6 ′ having respective centers at equal distances inside and outside the piezoelectric layers 2 ′ and 3 ′ with the outer lines sandwiched therebetween are overlapped.

By arranging the two through-holes 6 ′ in such a manner as to have a slightly overlapping portion along the radial direction, after firing, the electrode material filled therein and the piezoelectric layer itself shrink. It becomes a through-hole with a substantially oval shape.

In this embodiment, the diameter of the through hole is set to 0.2 mm.

As described above, by forming the through-hole into a substantially elliptical shape having a major axis in the radial direction, even if the positional accuracy of the through-hole is slightly deteriorated in manufacturing, the through-hole can be formed at the outer diameter end or the inner diameter end. It becomes easy to form a through hole. The other modes, manufacturing methods, driving methods, and the like are all the same as those of the first embodiment.

The multilayer piezoelectric element 1 ′ in the present embodiment
Can be incorporated in a rod-shaped vibrating wave motor in the same manner as in the first embodiment shown in FIG. 3, and in this case, the laminated piezoelectric element 1 'is a metal part 22 which is an elastic body of the vibrating body 21. ,
23 and bolts 24, the wiring board 8 is
It was tightened so as to be in close mechanical contact with.

The method of forming through holes formed in the laminated piezoelectric element according to the present embodiment may be applied to the second and third embodiments.

As a result, just as in the first embodiment, the performance and motor efficiency of the vibration wave motor were good.

(Fifth Embodiment) As described in the foregoing embodiment, the exposed through-holes of the outer diameter portion of the laminated piezoelectric element can be easily formed in the element. For example, the exposed through-hole 50 of the outer diameter portion, which is additionally shown in the conventional example of FIG. 8, is used as a mark for circumferentially positioning the laminated piezoelectric element when assembling the vibration wave motor. Can be determined from the side of the device.

Since the number of through-holes is originally a mark, the number of through-holes may be one or a plurality of discriminable ones, and the through-holes may be provided in the number of layers that can be visually identified. That is, at least one layer or a plurality of layers may be provided. In addition, the present invention is also effective for identifying different types of laminated piezoelectric elements and the like that cannot be identified from the appearance. Conventionally, in order to position the laminated piezoelectric element, another through hole for identification is provided in the uppermost layer, and the position is determined by using the mark as a mark when viewed from above the laminated piezoelectric element.

[0081]

As described above, according to the present invention,
When miniaturizing a laminated electro-mechanical energy conversion element such as a laminated piezoelectric element, the area of the effective piezoelectric active portion of the laminated piezoelectric element is enlarged while maintaining the reliability of the conventional through-hole, and further exposed to the outer periphery. It is also possible to attach a wiring board to the cross section of the through-hole to achieve electrical continuity with the outside. The influence of the vibration damping by the wiring board can be reduced, which greatly contributes to the improvement of the performance of the small vibration wave motor. It is also effective as a mark.

[Brief description of the drawings]

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

FIGS. 2A and 2B are a perspective view and an exploded perspective view of a laminated piezoelectric element showing a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a vibration wave motor incorporating the laminated piezoelectric element of FIGS. 1 and 6;

FIGS. 4A and 4B are a perspective view and an exploded perspective view of a laminated piezoelectric element showing a third embodiment of the present invention.

FIG. 5 is a sectional view of a vibration wave motor incorporating the laminated piezoelectric element of FIG. 4;

FIG. 6 is a perspective view of a laminated piezoelectric element showing a fourth embodiment of the present invention, and an exploded perspective view thereof.

FIGS. 7A and 7B are diagrams showing a method of forming a through hole.

FIG. 8 is a perspective view of a conventional laminated piezoelectric element and an exploded perspective view thereof.

FIG. 9 is a sectional view of a vibration wave motor incorporating the laminated piezoelectric element of FIG. 8;

[Explanation of symbols]

 1, 1 ', 10, 11 Multilayer piezoelectric element 2, 3, 2', 3 ', 12, 13 Piezoelectric layer 4, 5, 14, 15 Internal electrode 6, 6', 16 Through hole 7, 7 ', 17 Surface Electrodes 8, 18, 19 Wiring board 20, 20 'Vibration wave motor 21, 21' Vibrator 50 Through hole for mark

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuyuki Kojima 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Tohru Ezaki 1568-4 Onumada, Togane, Chiba Pref. Company F term (reference) 5H680 AA06 AA19 BB16 BC01 CC02 DD01 DD15 DD23 DD27 DD37 DD53 DD66 DD73 DD83 DD92 DD95 FF04 FF08 FF17 FF33 GG11 GG42

Claims (9)

[Claims] 1. A laminated electric device in which a plurality of layers having a plurality of electrode regions and having an electro-mechanical energy conversion function are stacked, and the plurality of electrode regions of the plurality of layers are connected using through holes. In the mechanical energy conversion element, at least a plurality of the through-holes are formed in an outer diameter or an inner diameter, or an outer diameter and an inner diameter, and the filler filled in the through-hole faces an end surface of the outer diameter or the inner diameter. Laminated electrical-mechanical energy conversion element. 2. The laminated electromechanical energy conversion device according to claim 1, wherein the through hole is formed in a substantially elliptical shape. 3. The multilayer electromechanical energy conversion device according to claim 1, wherein conduction from the outside is achieved from an end face of a through hole formed in the outer diameter portion or the inner diameter portion. 4. The insulating part around the through hole is formed substantially concentrically around the through hole of the outer diameter part or the inner diameter part of the laminated electro-mechanical energy conversion element. 4. The laminated electro-mechanical energy conversion device according to 2 or 3. 5. The device according to claim 1, wherein each of the plurality of electrode regions in the plurality of layers extends to an outer or inner edge of the laminated piezoelectric element except for a through hole and an insulating portion around the through hole. The laminated electricity according to any of the above items 4 to 4? Mechanical energy conversion element. 6. The multilayer electromechanical energy conversion device according to claim 4, wherein the through hole is not formed in the uppermost layer and the lowermost layer. 7. The multilayer electromechanical energy conversion device according to claim 1, wherein the through hole in one or more layers facing the end face of the outer diameter portion is used as a mark. 8. A green sheet having a size larger than the outer diameter of a finished product having an internal electrode formed on one side thereof,
Forming a through hole with the outer diameter or inner diameter position substantially at the center of the finished product, forming a through-hole filled with a filler as a laminate, firing the laminate, and subjecting the outer diameter portion to machining. A method for manufacturing a laminated electro-mechanical energy conversion element, wherein a predetermined outer diameter is obtained. 9. A green sheet having a size larger than an outer diameter of a finished product having an internal electrode formed on one side thereof is superimposed,
Two through-holes having portions slightly overlapping each other at substantially the outer diameter position of the finished product are formed substantially in a line in the radial direction, and the through-hole filled with a filler is formed into a laminate, and the laminate is fired. A method for producing a laminated electromechanical energy conversion element, wherein a predetermined outer diameter is obtained by machining the outer diameter portion.