JPH0225081A - Piezoelectric displacement element - Google Patents

Abstract

PURPOSE:To obtain a miniature camera of high efficiency by a method wherein a piezoelectric displacement element, provided with an electrode which is joined to a central electrode through the intermediary of a piezoelectric material, is made to have a such a structure that a large displacement can be obtained and it is extremely small in size toward a direction of displacement. CONSTITUTION:When a voltage is applied on a central electrode 1 of a piezoelectric displacement element 40, an electric field is induced between electrodes 27 and 25 and the electrode 1 to make the displacement of a piezoelectric material 26 occur, and the bending action of the material 25 happens. For instance, in a case of a photodetecting element actuator of a camera, a flexible substrate 61, whose shape is nearly the same that of the element 40, is overlapped with upside of the element 40 in parallel through the intermediary of a spacer 62, and a photodetecting element CCD is fixed to a central part of the substrate 61 in such a state that its photodetecting plane is in parallel with the substrate 61. The substrate 61 makes a photodetecting element 63 and a signal processing circuit electrically connected with each other, and all electrode 1 is fixed to a chassis 65 through the intermediary of a stad 64, which is housed in a camera. And, when a voltage is impressed on the electrode 1, the displacement of the element 63 occurs, and when the polarity of the voltage is changed, the element 63 is displaced in a reverse direction. Therefore, the CCD can be driven with a lens fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a pressure 1 displacement element used for minute positioning.

[Conventional technology]

The pressure tortoise displacement element is used to blow out the strain caused by applying a voltage to the piezoelectric material as displacement. - Membrane attachment is often used to fix one end of the element and to obtain displacement from an, but the pressure 'If' described in JP-A No. 57-92322 is
The outer periphery of an annular element with a bimorph (trademark) structure is fixed, like a cell element.

There is also one in which a driven body attached to the inner peripheral portion is displaced in the axial direction of the element.

However, in the case of the former piezoelectric displacement element, it is difficult to shorten the length of the element in the displacement direction in order to obtain a sufficient amount of displacement. In the case of the superior piezoelectric displacement element, the length of the element in the displacement direction is shortened, but it is difficult to obtain a displacement l& of the magnitude of light.

(Unsolved Problem to be Solved by the Invention) As described above, in the past, it was possible to simultaneously obtain a displacement amount equivalent to the amount of light of the element and to shorten the length of the pressure displacement element in the displacement direction. It was difficult to do so. The present invention aims to solve this problem and provide a pressure gEfIi element that can obtain a large amount of displacement and has an extremely small dimension in the displacement direction.

[Structure of the invention]

(Means for resolving charging issues) In order to achieve the above object, the present invention.

(1) A center electrode, a slit provided so as not to be connected to the end of the center pole, a piezoelectric material bonded to at least one of the center electrodes, and a piezoelectric material bonded to the center electrode via the piezoelectric material. It was made into a piezoelectric element consisting of electrodes. Also.

(A center electrode having a hole, a slit provided around the hole so as not to be connected to the end of the center electrode, a piezoelectric material to be joined to at least one surface of the center electrode, and a slit provided around the hole so as not to be connected to the end of the center electrode, and a piezoelectric material that is bonded to at least one side of the center electrode, The piezoelectric displacement element consists of an electrode connected to a central electrode.

[Effect]

With the piezoelectric displacement element having the above configuration, in (1) and (2), a large displacement difference occurs between the adjacent portions surrounding the slit in a direction perpendicular to the six faces of the element.

In (2), for example, adjacent pieces of the piezoelectric material to be divided are made to have different bending motions.
When such polarization is arranged, a large displacement difference occurs between adjacent comrades in a direction perpendicular to the front surface of the element.

For example, if the electrodes are arranged so that adjacent pieces of piezoelectric material divided by the slit ζ perform the same bending motion, the inner circumferential part and the outer 1ff1 part of the element will bend in the direction perpendicular to the inner surface of the element. This results in a large displacement difference.

Therefore, a piezoelectric displacement element capable of obtaining a large amount of displacement and having extremely small dimensions in the direction of displacement is realized.

(Example) The present invention will now be described in detail with reference to Figure f.

FIG. 1 is a top view of a central electrode used in a piezoelectric displacement element showing one embodiment of the present invention. The piezoelectric displacement element 40f of this embodiment has a rectangular shape with two disjoint parallel strips 2 and 3 of the same size at the end E of the center electrode l. Electrodes 27 and 28, which are bonded to the center electrode 1 via a piezoelectric material 26, are respectively arranged in determined regions as shown in FIGS. 2 and 3. The center electrode 1 is divided into three partial regions 8 to 11 by the slit 2.3 and the dividing lines 4 to 71 connecting the upper end of the slit IJ y and the side R of the center electrode 1. Next, each of the partial regions 8 to 10 is divided into three by dividing lines 11 to 16, one end of which touches the slit 2 or 3, to form a total of nine unit regions 17 to 25. Then, as shown in FIG. 4, electrodes 27, 2B are bonded to the unit regions 17 to 25 via the piezoelectric material 26.

However, in this embodiment, electrodes of the same polarity are not arranged adjacent to each other in the unit regions 17 to 25, and the end region 2
9,301 The electrodes 27 and 28 are not arranged. However, the piezoelectric material 26 is bonded so that when a voltage is applied to the center electrode 1, the direction of the field generated between it and the electrodes 27 and 28 is the same. Here, in Fig. 4 (A-
The cross-sectional view taken along line A is shown, and the cross-sectional views taken along lines B-B and C-C are shown in FIG. They have a bimorph structure with the same polarity. Further, in one embodiment, the dimensions of polarization 27°28 along the slits 2 and 3 are set to 1:2:1.

When a voltage is applied to the center electrode l of the 1st displacement element 40 having such a configuration, an electric field is generated between the electric currents 27 and 28 and the center electrode l, causing displacement of the piezoelectric material 26.
A bending motion as shown in the ggS diagram occurs. Here, Figure 5 (m
l corresponds to Fig. 4 et al.) and is bent in a convex shape at the center.
Figure fb) corresponds to Figure 4 (cl) and is bent into a concave shape at the center.This kind of bending operation can be applied, for example, to an actuator for a light-receiving element in a camera as shown in Figure 6. A flexible printed circuit board 61 having approximately the same shape as the element 40 is stacked parallel to the top of the piezoelectric displacement element 40 with a spacer 62 interposed therebetween, and a light receiving element (CCD: Charge) is mounted in the center of the flexible printed circuit board 61.
Coupled 1)evlce) is fixed such that its light receiving surface is parallel to the flexible printed circuit board 61. The flexible printed circuit board 61 is.

The light-receiving element 63 and the processing circuit No. 16 (not shown here) are electrically depleted. Further, the center electrode 1 is fixed to the chassis 651 via a stud 64, and is housed inside the camera. With the above configuration, when an arbitrary voltage is applied to the center electrode 1, the light receiving element 63
Make the displacement h shown in bl.

Of course, if you change the positive or negative voltage applied, the light receiving element 6
3 is displaced by h in the opposite direction, a total displacement of 2 h can be secured. in this way.

In order to generate sufficient displacement in the original axis direction, the focal point can be changed to the CCDI by driving the camera lens as in the conventional case.
Rather than increasing the focus, the lens remains fixed and the focus can be softened by making full use of COD, thereby providing a compact and cheap camera.

In the previous embodiment, the clothing Il! 7 objects (light receiving element 63)
is electrically connected to the outside, but there is no need for this connection to drive the driven object.
The driven object may be directly connected to the pressure displacement element 40 without using the spacer 62 as shown in FIG. At that time, the covering part #b
The object is directly connected to the central pole 1, and there is a pressure-sensitive material 26 in between.
If the structure is such that it is not pinched, fatigue peeling can be prevented. This means that the pressure 1 changer 40 and the spacer 62
．． I agree with you about the dark side of Stud 64. Also 1
For example, in order to increase the accuracy in the moving direction of the driven object, a sliding bearing 66 is attached to one pole 1 in the center, and a shaft 67 is attached to the chassis 65, as shown in FIG. 67 may be slidable.

7 to 10 are top views of a central electrode used in a piezoelectric displacement element showing other embodiments of Akira Honyaku, and will be described in sequence below.

The piezoelectric displacement element 70 shown in FIG. It consists of a combination of lines. In addition, ■:■:■＝■′:■′:
■'=l:2:l. Pressure material (not shown)
The arrangement of electrodes 27 and 28 is the same as in the previous example. With such a configuration, when this piezoelectric displacement element 70 is applied as shown in FIG. 6, the cross-sectional area of the fixed part with the stud 64 can be increased, so that the piezoelectric displacement element 70 has a larger cross-sectional area than when a vertical element with the same area is used. It is possible to control the total dynamics, and as a result, it is possible to obtain a large amount of driving force.

The piezoelectric displacement element 80 shown in FIG.
．． 3, and six slits 848 to 84f are formed in the direction perpendicular to the ribs 82 and 83, leaving a hinge portion at the end thereof. FE? ff
, material (not shown) and electrodes 27 and 28 are different from the previous two embodiments, and each partial region 85a to 85
Everything in c is one @, and the adjacent partial areas 85a~
The comrades of 85C were made with piezoelectric material f+ and welded together to form different electrodes, making six such configurations.
When a voltage is applied to the center line of the L displacement element 80,
A bending motion as shown in FIG. 11 occurs. Here the first
Figure 1 (at is a sectional view taken along the line A'-A' of Figure 8, with a convex shape at the center and a bend in Figure 11 (b).
B'-t3'i section (Ishizuwaka L (C'-C' line section: A
It has 14 curves in the center concave shape.

As can be seen by comparing Fig. 5 and Fig. @11, in this similar example, the partial regions 85a-85c constitute the folded structure 8, so that it is not a state in which two piezoelectric displacement elements are stacked. Equivalent displacement can be obtained.

The l:E electric displacement element 90 in FIG.
82 and 83, and slits 84a to 84f having substantially the same shape as the piezoelectric displacement element 80 of FIG.

The piezoelectric material (not shown) and the arrangement of the electrodes 27, 28 are the same as in the previous embodiment. In this embodiment E having such a configuration, the IEf element 70.8 of FIGS. 7 and 8 is used.
Combines the advantages of 0.

Piezoelectric rfL that provides large driving force and large displacement
This becomes element 90.

The piezoelectric displacement element lOO in FIG. 10 includes slits 102 and 103 having substantially the same shape as the slits 2 and 3 formed in the piezoelectric displacement element 40 in FIG. 1, and these slits.

Eight new slits 104a to 104h and f are newly formed in the right angle direction from the ends of the parts 102 and 103. From this, the intermediate positions of the partial regions 105a to 105c and the end region 1 are formed.
06°107 are connected by a hinge portion. Piezoelectric material (not shown) and electrode 2
The arrangement of 7.28 basically uses the bonding method shown in Figure 8, but in this embodiment, the piezoelectric material is not bonded to the hinge portion 1, and furthermore, the piezoelectric material is not bonded to the end regions 106 and 107. + Joining is performed. At this time, the end regions 106 and 107 and the partial region 105a have the same single pole 27 of all -C. The bending motion in this embodiment f is shown in the A'-A' line cross section in FIG.
The line cross section corresponds to that shown in FIG. 11 tbl, but since the end regions 106 and 107 undergo a bending motion that is convex toward the front in the drawing, the piezoelectric displacement has a very large amount of displacement as a whole. This becomes element 100.

In the above embodiment, vh extending in the horizontal direction of one drawing
The same effect can be achieved even if it is 1.

FIG. 12 to FIG. 14 show still another embodiment of the present invention. These pressure displacement elements are
) are arranged in parallel in an annular manner.

The piezoelectric displacement element 120 in FIG. 12 has a circular central electrode 12
A round hole 122 is provided in the center of the hole 122, and the state is close to a tangent to the outer diameter of the round hole 122. J v
) 123 are formed at equal intervals, and 1
All eight partial regions 124 have the same area. The method of joining the piezoelectric material (not shown) and the electrodes 27 and 28 is as follows:
The time setting of a driven object can be roughly divided into two methods depending on the method.

First, as shown in Figure 12(b).

The method of forming all eight partial regions 124 with the same bonding pattern is suitable for fixing the outer periphery of the center electrode 121 and attaching the driven object to the inner periphery (or vice versa). generates a large displacement in the vertical direction of the drawing.

In addition, as shown in Fig. 12), a method of arranging opposite polarization for each adjacent partial region is to
This is suitable for Fa-Zeng, where the driven object is arranged to straddle one another, and generates a displacement with a large driving force in the vertical direction of one drawing.

Although the central electrode 121 shown in FIGS. 13 and 14 has a different shape of the slit 123, it can be transformed into a pressure 1 with the same effect by using 8g12+b) or fcl t other bonding methods. Even in these cases, the number of slits is not necessarily eight, and may be any number.

Although the above-mentioned embodiments specify the piezoelectric material and the method of joining the electrodes, the piezoelectric displacement element of the present invention is not limited to these, and may be any device that realizes a similar bending action. For example, even if piezoelectric materials are bonded separately for each unit area, the electric field generated in the piezoelectric displacement element may vary depending on each unit area, but the result will be the same depending on the positive and negative bonding methods of the electrodes. Any material that realizes the bending motion may be used. Of course, the piezoelectric material and one pole may be joined to only one side of the central electrode.

Furthermore, the number of unit regions for electrode bonding in each partial region may be arbitrarily selected for each partial region, such as 5, for example, 5 instead of 3, or 4 instead of 2. .

〔Effect of the invention〕

As described above, according to the present invention, a piezoelectric displacement element that can obtain a large displacement position and has an extremely small dimension in the displacement direction is realized.

[Brief explanation of the drawing]

1 to 4 are a top view and a cross-sectional view of a piezoelectric displacement element showing an embodiment of ficl of the present invention, FIG. 5 is a cross-sectional view showing a bending operation of the present invention, and FIG. 7 to 10 are top views of a piezoelectric conversion element showing an embodiment of the pond of the present invention, and FIG. 11 is a cross-sectional view showing a second application example of the present invention. A cross-sectional view showing another bending cut,
12 to 14 are top views of a pressure tf stand-up element showing still another embodiment of the present invention. ], 121...Central 1 Chen, 2, 3, 82, 83° 84 a ~ 84 f, 102, 103. 104a
~104h, 123... Thrive% 8,9,10
, 85g-85c, 105a-105c, l 24
...Partial region, 26...Piezoelectric material, 27.28...
・Electric @, 40.70.80.90.100,120...
・Pressure 1 Hentachi Yuko. Agent Patent Attorney Ken Nori Chika Hikaru Matsuyama Figure 2 (α) Figure <a> B (bλ Figure (Goton Figure (d) <b) Figure QO <b> Figure No. Figure diagram

Claims (5)

[Claims] (1) A central electrode, a slit provided so as not to be connected to an end of the central electrode, a piezoelectric material bonded to at least one surface of the central electrode, and a piezoelectric material bonded to the central electrode via the piezoelectric material. A piezoelectric displacement element comprising an electrode. (2) The piezoelectric displacement element according to claim 1, wherein adjacent piezoelectric displacement elements across the slit perform different bending operations. (3) a central electrode having a hole; a slit provided around the hole so as not to be connected to an end of the central electrode; a piezoelectric material bonded to at least one surface of the central electrode; 1. A piezoelectric displacement element comprising: an electrode connected to a central electrode via a central electrode; (4) The piezoelectric displacement element according to claim 3, wherein adjacent members across the slit perform different bending operations. (5) The piezoelectric displacement element according to claim 3, wherein adjacent members across the slit perform the same bending motion.