JPS62152379A - Bidirectional microdisplacement device - Google Patents

Abstract

PURPOSE:To enable a movable carriage to perform microdisplacement independently in two(2) directions in a simple constitution, by providing a rectangular hollow portion except at the middle portion in a plate piezoelectric element and by fitting a movable carriage to the centre of the middle portion of the piezoelectric element. CONSTITUTION:Both ends of a rectangular piezoelectric element 7 with a polar ize axis in the thickness direction and having electrodes on upper and lower surfaces are fixed between a recess base 13 and fixed members 14a & 14b with an insulation 16 inserted in between. A rectangular hollow portion is pro vided between the both fixed ends of the piezoelectric element 7 except at its middle portion. One of the upper and lower surface electrodes of the piezoe lectric element 7 forms a common electrode 7a; the other electrode on the other surface in the middle portion of the piezoelectric element is separated into circumferential electrodes 7b and 7c. The electrodes in the middle portion of the piezolectric element are further separated into electrodes 7d and 7e in its middle part at right angles with perfect to fixed ends and a movable carriage 15 is installed at the centre of the middle portion of piezoelectric element.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a two-direction minute displacement device for precise positioning in two directions on the same plane. This device can be used for positioning a color solid-state image sensor of a video camera, a displacement device for a high-resolution solid-state image sensor, and the like.

Conventional technology Positioning by micron or submicron displacements has conventionally been performed by mechanical means, using stepping motors or DC servo motors, and converting rotational motion into linear motion by twisting the pole. For this reason, in order to improve accuracy without eliminating errors caused by mechanical coupling, the device must become larger.

Therefore, a micro-displacement device using the inverse piezoelectric effect of a piezoelectric element that can be electrically controlled was devised, and
There is an insect type movement mechanism as shown in Japanese Patent No. 97. FIG. 3 is an explanatory diagram of the above-mentioned insect-shaped moving mechanism, which has a structure in which clamp elements 2.3 using electrostatic force or electromagnetic force are attached to both ends of the cylindrical piezoelectric element 1. In the same figure (a), the clamp element 2.3 is clamped to the fixed base 4, in the same figure (b), the clamp element 3 is made free, and in the same figure (c), a voltage is applied to the piezoelectric element 1, and the piezoelectric element 1 is growing. In the same figure (d), the clamp element 3 is clamped to the fixed base 4 again in the extended state, the clamp element 2 is made free in the same figure (e), the applied voltage is removed in the same figure (f), and the same figure In (g), the clamp element 2 is clamped again. This results in the same state as in FIG. 2(a), with a displacement of Δe. By attaching the moving mechanism in two directions, a two-direction minute displacement device can be easily obtained. Since the strain caused by the inverse piezoelectric effect is small, highly accurate positioning is possible.

Also, Special Publication No. 58-130677, No. 58-1967
In Publication No. 73, a rectangular piezoelectric element having a polarization axis in the thickness direction is bonded to the upper and lower surfaces of a thin metal plate of the same shape, and a bending vibrator (bimorph vibrator) in which one end or both ends are fixed is used. A displacement device for a solid-state image sensor has been disclosed which increases the light-receiving area by displacing the solid-state image sensor and achieves higher resolution.

FIG. 4 shows one example of a unidirectional minute displacement device using the bending vibrator. The bending transducer 5.5 with both ends fixed is arranged in parallel, and the bending transducer 5.5 has the maximum amount of displacement.
A movable table 6 on which a solid-state image pickup device, etc. is mounted is provided at the center position of '.

Problems to be Solved by the Invention Although it is possible to easily create a two-way fine displacement device by attaching the above-mentioned insect-shaped minute displacement device in two directions on the same surface, one of the driving bodies is constantly forced by electrostatic force, Alternatively, it must be clamped using electromagnetic force, so in devices that are portable or tilted, it is necessary to separately secure objects that move when not in operation, making the structure complex and increasing the size of the device. Additionally, when moving, the weight of the moving object concentrates on the part where the clamp is removed, making it mechanically unstable.

In the case of a micro-displacement device using a bending vibrator, the amount of strain is large (it can be removed, but the generated force is weak and it is not possible to move heavy objects. Also, when a large load is applied, the resonant frequency of the vibrator decreases, causing the drive Harmonic components of the frequency tend to resonate, causing problems in durability.Therefore, in order to create a two-direction minute displacement device, a displacement device (first displacement unit) using the above-mentioned bending vibrator, Although it is easy to think of means to displace the ! (second displacement unit),
Since the weight of the second displacement unit is applied to the first displacement unit, in order to reduce the influence of the weight of the second displacement unit, it is necessary to make the bending vibrator of the first displacement unit thicker, resulting in an increase in size.

Additionally, durability also poses a problem.

Means for solving the problem A plate-shaped piezoelectric element having a polarization axis in the thickness direction and electrodes on the upper and lower surfaces is used, both ends of which are fixed, and the center part of the piezoelectric element is left open between the fixed ends. A rectangular hollow part is provided in the central part, the piezoelectric element electrode in the central part is separated from the peripheral surface electrode, and the electrode of the central part piezoelectric element is also separated in the central part in a direction perpendicular to the fixed end. It is constructed by attaching a moving platform to the center of the

Operation In the above configuration, if a voltage is applied to the upper and lower surface electrodes of the fixed end portion of the piezoelectric element, it functions as a lateral camera that generates strain in the longitudinal direction, and displacement occurs in a direction perpendicular to the fixed end portion. The moving table at the center of the central piezoelectric element is
It is possible to make a minute displacement in the direction. Furthermore, when a voltage is applied to the upper and lower surface electrodes of the central piezoelectric element, strain is similarly generated in the longitudinal direction, allowing the central movable stage to be slightly displaced in a direction parallel to the fixed end portion. As a result, independent minute displacement devices in two directions can be constructed on the same piezoelectric element, resulting in miniaturization and simple structure.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention. Reference numeral 7 denotes a rectangular piezoelectric element having a polarization axis in the thickness direction and electrodes on the upper and lower surfaces, and its both ends are connected to the concave base 13 and fixing members 14a, 14 by screws or adhesive, with an insulator 16 in between.
It is fixed between b. A rectangular hollow part is provided between the piezoelectric element 7 and both fixed ends, leaving the center part, and one of the upper and lower surface electrodes of the piezoelectric element 7 is used as a common electrode 7a, and the piezoelectric element central part electrode on the other surface is used as a common electrode 7a. Surrounding electrode 7b.

It is separated from 7c. Further, the central electrode of the piezoelectric element is also separated at the central part in a direction perpendicular to the fixed end to form an electrode 7 d s.
7e, and a moving stage 1 is installed in the center of the piezoelectric element.
5 is attached. If a voltage V is applied to the applied voltage terminal 8 of the common electrode 7a of the piezoelectric element 7 and the applied voltage terminal 9 of the electrode 7b, and a voltage -■ with the same voltage and the polarity is applied to the applied voltage terminal 10 of the electrode 7C. , the piezoelectric element itself causes strain in the thickness and length directions, and since the amount of displacement in the length direction is larger than the thickness, displacement occurs in the direction perpendicular to the fixed end portion, and the amount of displacement is determined by the applied electric field. and piezoelectric constant d
Proportional to 31. Since the polarities of the applied voltages are different, the electrodes 7b and 7c are displaced in opposite directions, and the piezoelectric element 7
It functions as a lateral oscillator that slightly displaces the central part of the oscillator in one direction. Similarly, when voltages with different polarities are applied to the common applied voltage terminal 8 and the applied voltage terminals 11.12 of the electrode 7d17e of the central piezoelectric element, the electrodes 7d and 7e are displaced in opposite directions, and the central portion Mobile platform 15
can be slightly displaced in a direction parallel to the fixed end portion. As a result, independent minute displacement devices in two directions can be constructed on the same piezoelectric element, resulting in miniaturization and simple structure. Moreover, since the piezoelectric element itself is distorted,
It is possible to generate large forces and displace heavy objects. The advantage of being able to be miniaturized in this way is that in applications where a semiconductor element such as a solid-state image sensor is minutely displaced, the displacement device itself can be packaged together with the semiconductor element.

Figure 2 shows an example of packaging. The solid-state image sensor 17 is pasted on the movable stage 15 of the two-direction micro-displacement device with conductive adhesive or the like, and the two-direction micro-displacement device is fixed inside a case 18 made of ceramic or the like. It is enclosed in a case 18 by arranging a glass that transmits light.

Electrical wiring to the solid-state image sensor 17 and the piezoelectric vibrator necessary for two-direction displacement is taken out to the outside through electrodes 19 printed on the case 18. Also, since a single-plate piezoelectric element is used, it is possible to connect the piezoelectric vibrator to the bending vibrator or There is no need for adhesion between piezoelectric elements or adhesion between piezoelectric elements and metal etc., which is required in laminated piezoelectric bodies, etc., and reliability is improved without deterioration of characteristics of the piezoelectric element due to adhesion.

Effects of the Invention According to the present invention, it is possible to construct minute displacement devices independent in two directions on the same piezoelectric element, so it can be made smaller, the structure is simple, and because the strain of the piezoelectric element itself is used, a large force can be generated. It is possible for this to occur.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a two-direction minute displacement device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the two-way minute displacement device according to the present invention packaged, and FIGS. 3 and 4 are FIG. 2 is a front view and a perspective view of a conventional micro-displacement device, respectively. 7...Piezoelectric element, 7a17bs 7cs 7cL
7e...piezoelectric element electrode, 8.9.10.11.1
2... Applied voltage terminal, 13... Concave base, 14a
, 14b... fixed member, 15... moving table. Name of agent Patent attorney Toshio Nakao and one other person 112 Figure 3 t11 - Itoto

Claims (2)

[Claims] (1) A plate-shaped piezoelectric element having a polarization axis in the thickness direction and electrodes on the upper and lower surfaces is used, and both ends of the piezoelectric element are fixed by a fixing member, leaving the center part of the piezoelectric element between the two fixed ends. A rectangular hollow part is provided, at least one of the upper and lower surface electrodes of the piezoelectric element in the central part is separated from the surrounding surface electrode, and furthermore, at least one of the upper and lower surface electrodes of the central piezoelectric element is also perpendicular to the fixed end. A two-direction minute displacement device, characterized in that it is separated at the center and a moving stage is attached to the center of the center piezoelectric element. (2) Among the electrodes on the upper and lower surfaces of the piezoelectric element, one surface is used as a common electrode, and on the other electrode surface, voltages with a phase difference of 180 degrees are applied to the fixed end portion electrodes separated at the center of the piezoelectric element, and Claim 1, characterized in that the piezoelectric element is configured to apply a voltage to the separated electrodes at the center of the piezoelectric element, which is independent of the voltage applied to the fixed end partial electrode and whose phase is 180 degrees different from each other. 2 described in Section 1
Directional minute displacement device.