JPH04331303A - Slight motion apparatus - Google Patents

Abstract

PURPOSE:To obtain a slight motion apparatus which enables execution of a stable slight motion operation in a wide extent. CONSTITUTION:First and second sliders 6a and 6b are disposed between guide surfaces formed of one side of a side plate 2 and the respective one side of clampers 9a and 9b and these sliders are pressed and fixed elastically between the guide surfaces by parallel springs 7a and 7b through the intermediary of the clampers 9a and 9b. First and second piezoelectric bodies which can remove the fixation by these parallel springs and a third piezoelectric body 3c which connects and integrate the two sliders with each other are provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine movement device for a probe of a scanning probe microscope, for example.

0002

[Prior Art] Generally, a scanning tunneling microscope (STM)
) and scanning atomic force microscopes (AFM) use a probe with a sharp tip to approach the sample surface, and the atoms at the tip of the probe and the
It detects tunneling currents and atomic forces based on physical interactions with atoms on the sample surface, and outputs information on changes in the sample surface at the atomic scale as the probe scans along the sample surface. It is used to obtain a two- or three-dimensional information distribution image on a CRT or the like.

[0003] When scanning the probe side during the above scanning, a tripod piezoelectric drive body or a cylindrical piezoelectric tube is generally used for this drive. However, with such a driving member, the scanning range is narrow and sufficient observation cannot be performed.

[0004] Accordingly, as a drive device capable of scanning a wide range and having micro-motion resolution on an atomic scale level, a specimen-side driven inchworm device has been proposed, for example, in Japanese Patent Laid-Open No. 52006/1983. . This conventional example will be explained with reference to FIGS. 5(A) and 5(B).

[0005] First and second sliders 31A and 31B, whose one end faces are pressed against the surface 38 of the side wall 30, are fixed to both ends of the first piezoelectric body 32, respectively. On the other end surfaces of these sliders 31A and 31B, second and third piezoelectric bodies 33A and 33B are fixed at one end surface side. The other end surfaces of both piezoelectric bodies 33A, 33B are slidably abutted on blocks 34A, 34B having surfaces 39A, 39B parallel to the pressed surface 38 of the side wall 30. These blocks 34A, 34B are connected by screws 35A, 35B.
It is fixed to a base 36 that is integral with the side wall 30. In the above configuration, the moving stage is the slider 31A or 31B.
and by the inchworm action described below,
Slight movement is sent.

First, by applying a voltage to the second piezoelectric body 33A and expanding it in the direction shown by the arrow, the first slider 31A is pressed and fixed against the side wall 30. On the other hand, at this time, no voltage is applied to the third piezoelectric body 33B, and the second slider 31B is released from the side wall 30. Next, a voltage is applied to the first piezoelectric body 32 to determine the minute movement amount of the movement stage. As a result, this piezoelectric body 32
is extended by a predetermined distance Δd in the direction shown by the arrow, and the second slider 31B is moved by the distance Δd as shown by the broken line. Then, while applying a voltage to the third piezoelectric body 33B and leaving no voltage applied to the second piezoelectric body 33A, the second slider 31B is extended in the direction of the arrow and fixed to the side wall 30, and the first slider 31A is to liberate. Next, the voltage application to the first piezoelectric body 32 is released, and the first slider 31A is attracted toward the second slider 31B by the distance Δd. The translation stage is thus moved by a distance Δd in one direction, for example in the X direction. By continuing the above steps n times, the slider 31B becomes d=Δd
It travels a distance of xn and moves the moving stage by a distance of d.

[0007] This conventional fine movement device consisting of an inch worm can set an arbitrary movement unit amount simply by changing the voltage value applied to the first piezoelectric body 32, and has the ability to
It can be moved in minute units close to electronic resolution. Moreover, if the side walls 30 and blocks 34A, 34B are parallel and flat over several millimeters, the wide range of travel distance required by the STM device can be easily achieved.

[0008]

However, in the conventional fine movement device described above, when fixing the moving stage, it is necessary to apply voltage to both piezoelectric bodies 33A and 33B at the same time.

However, in an STM device, the voltage applied to the piezoelectric body is several hundred volts, and applying this voltage to fix the moving stage causes instability of the power supply and temperature fluctuations of the piezoelectric body. A drift condition occurs and the stage of the STM device becomes unstable. An object of the present invention is to provide a fine movement device capable of stable fine movement over a wide range.

0010

[Means for Solving the Problems] Therefore, in order to achieve the above object, the fine movement device of the present invention includes first and second sliders disposed between two guide surfaces so as to be movable along them. two elastic bodies that elastically press and fix these sliders between guide surfaces, and first and second piezoelectric bodies that are independent of each of these elastic bodies and can release the elastic pressure of the elastic bodies. , and a third piezoelectric body that connects and integrates both the sliders.

[0011]

[Operation] A voltage is applied to the second piezoelectric body to release the second slider from being pressed and fixed, and a voltage is applied to the third piezoelectric body to cause it to expand. As a result, the second slider is displaced in one direction by the extension of the third piezoelectric body. Next, a voltage is applied to the first piezoelectric body to release the first slider from being pressed and fixed, and the voltage applied to the third piezoelectric body is released. As a result, the first slider is displaced in the direction of displacement of the second slider. By repeating this operation, the moving stage provided on the slider is moved within a predetermined range.

0012

[Example] Below, Figure 1 (A), (B) and Figure 2 (C
) and (D), a fine movement device according to an embodiment of the present invention will be described. In addition, (A), (B), (C) and
(D) is a perspective view, a side view, a plan view, and a front view of the device.

In the figure, reference numeral 1 indicates a base, and a side plate 2 is provided upright on the upper surface of one end side of the base. Also, this base 1
A convex portion 3 having a flat upper surface is formed near the side plate 2 on the upper surface thereof so as to extend along the side plate 2 in the X direction. The convex portion 3 has a pair of through holes 4a and 4b extending in parallel to each other in the Y direction with a predetermined interval in the X direction.
is formed. One end side of these through holes 4a, b4 faces the side plate 2, and therein are first and second piezoelectric bodies 5 that can be expanded and contracted in the Y direction by applying a voltage.
a and 5b are inserted through the through holes 4a and 4b so that both ends protrude from the through holes 4a and 4b, respectively. One end surface of these piezoelectric bodies 5a, 5b is adhered to the inner surface (guide surface) of the side plate 2. First and second sliders 6a and 6b are mounted on the upper surface of the convex portion 3 so as to be slidable in the X direction so as to be positioned above the piezoelectric bodies 5a and 5b, respectively. These sliders 6a, 6b preferably include the piezoelectric body 5
It is made of ceramic having approximately the same coefficient of thermal expansion as a and 5b. Further, between these sliders 6a and 6b, there is a third piezoelectric body 5c, and both ends of the third piezoelectric body 5c are connected to the sliders 6a and 6b.
are provided so as to be adhered to mutually opposing surfaces of the. This third piezoelectric body 5c is set to be able to expand and contract in the X direction by applying a voltage. Thus, both sliders 6a, 6b and the third piezoelectric body 5c constitute a movable part of the inchworm.

First and second parallel springs 7a and 7b are fixed to the upper surface of the other end of the base 1 with screws 8a and 8b. These first and second parallel springs 7a,
7b is the first and second slider 6a, 6b;
They face each other via first and second clampers 9a and 9b. These clampers 9a, 9b are provided with parallel springs 7a
, 7b, and when no voltage is applied to the first and second piezoelectric bodies 5a, 5b, the biasing forces of these springs 7a, 7b cause the sliders 6a, 6b to One side (guide surface) makes surface contact and presses them in the opposite Y direction, and these sliders 6a, 6b
is clamped and fixed between the side plate 2. In addition, at this time, so that a predetermined gap is created between the clampers 9a and 9b and the first and second piezoelectric bodies 5a and 5b,
The piezoelectric bodies 5a, 5b have a total length (Y
direction) is set to be slightly shorter. The positions of the parallel springs 7a, 7b are set by adjusting screws 10 so that the gaps formed between the clampers 9a, 9b and the first and second piezoelectric bodies 5a, 5b are at a predetermined distance.
a, 10b.

In the fine movement device configured as described above, when no voltage is applied to the first and second piezoelectric bodies 5a and 5b, the slider 6a is moved by the biasing force of the parallel springs 7a and 7b.
, 6b are pressed and fixed to the side plate 2 via clampers 9a and 9b (slider clamps). When a voltage is applied to the first and second piezoelectric bodies 5a and 5b, they extend in the Y direction, displacing the clampers 9a and 9b in the same direction, and causing the slider 6 by these clampers 9a and 9b to move in the same direction.
The fixation of a and 6b is released (release of the slider), and the sliders 6a and 6b are made movable along a pair of guide surfaces parallel to the X direction. Therefore, now the first slider 6
When a predetermined voltage is applied to the third piezoelectric body 5c with the second slider 6b clamped and the second slider 6b released, the piezoelectric body 5c extends in the X direction by a length proportional to this voltage value. The second slider 6b is displaced in the same direction. Next, when the voltage applied to the third piezoelectric body 5c is released while the second slider 6b is clamped and the first slider 6a is released, the piezoelectric body 5c contracts in the X direction by the amount of extension. The first slider 6a is displaced in the same direction. By repeating this series of operations, the entire inchworm, together with a moving stage (not shown) fixed thereto, moves in the X direction by a distance equal to the number of operations x 1 operation,
The moving stage can be moved over a wide range. Of course, the first slider 6a and the second slider 6
The inchworm can also be moved in the anti-X direction by reversing the clamped state and released state with b.

[0016] In the inchworm having the above configuration, the first
Furthermore, since the sliders 6a and 6b are clamped when the voltage applied to the second piezoelectric bodies 5a and 5b is released,
There is no possibility that weak vibrations generated when a voltage is applied to these piezoelectric bodies 5a and 5b are transmitted to the inchworm, and that weak noises do not affect surrounding electric circuits (not shown). Furthermore, the sliders 6a and 6b are piezoelectric bodies 5a and 5.
Since the piezoelectric bodies 5a, 5b and the clampers 9a, 9b are made of ceramic whose coefficient of thermal expansion is almost equal to that of the piezoelectric body 5b, the gaps between the piezoelectric bodies 5a, 5b and the clampers 9a, 9b are hardly affected by ambient temperature changes, and therefore the entire inchworm operation will not become unstable due to changes in ambient temperature.

Next, a fine movement device according to another embodiment will be explained with reference to FIGS. 3A to 3D and FIGS. 4A and 4B. In addition, (A), (B), (C) of Fig. 3
, and (D) are respectively a front view, a side view, a top view, and a bottom view of the device, and (A) and (B) of FIG.
They are a perspective view and a developed view of a cylindrical piezoelectric body used in this device.

In FIG. 3, the reference numeral 11 indicates a base, and at the upper and lower ends of this one side surface, there are side surfaces facing this one side surface, respectively, and first and second bases that are elastically deformable in a direction away from the base 11. Arm portions 12a and 12b are integrally provided in a protruding manner. Triangular grooves 13a, 13b, 13c are formed on the surfaces of the base 11 and arm portions 12a, 12b that extend in the X direction, and guide surfaces extending approximately parallel to each other are formed on the inner surfaces of these triangular grooves. It consists of A groove 13 between the base 11 and the first arm portion 12a
A first slider 14a is provided between a and 13b, and grooves 13a and 13c are provided between the base 11 and the second arm portion 12b.
A second slider 14b is located between the arm portions 12a,
They are each clamped by the elastic force of 12b. These sliders 14a, 14b have triangular grooves 13a, 13b.
, 13c so that the inner surface (guide surface) and outer surface of
It has a cylindrical shape. And these sliders 14a
, 14b, a cylindrical third piezoelectric body 15c is provided such that both ends of the third piezoelectric body 15c are adhered to mutually opposing flat end surfaces of the sliders 14a and 14b. This third piezoelectric body 15c is set to be able to expand and contract in the X direction and the circumferential direction (Θ direction) by applying a voltage, as will be described later. Thus, both sliders 14a, 14b and the third piezoelectric body 15c constitute a movable part of the inchworm.

Near the ends between the base 11 and the first and second arm parts 12a and 12b, first and second piezoelectric bodies 15a and 15b, which are extendable and contractible in the Y direction, have one end surface. They are attached to the side surfaces of the base 11, respectively. The other ends of the piezoelectric bodies 15a, 15b extend to near one opposing side surface of the arm portions 12a, 12b. When no voltage is applied to these piezoelectric bodies 15a, 15b, the other end faces are connected to the arm portions 12a, 12b.
It is spaced apart by a small distance from the extending ends of adjustment screws 16a and 16b screwed in from the other side. Thus, piezoelectric body 1
When no voltage is applied to 5a, 15b, sliders 14a, 14b are clamped and fixed between triangular grooves 13a, 13b, 13c by the elastic force of arm portions 12a, 12b. And piezoelectric bodies 15a, 15b
When a predetermined voltage is applied to these piezoelectric bodies 15a, 15
b extends in the Y direction, presses the adjustment screws 16a, 16b, and moves the arm portions 12a, 12b in the Y direction against these elastic forces.
Mutate in the direction. As a result, sliders 14a, 14
b is released from the triangular grooves 13a, 13b, and 13c.

The third piezoelectric body 15c can expand and contract along the central axis, and can also expand and contract (rotate) in the circumferential direction. An example of a piezoelectric material capable of rotation and linear motion with one degree of freedom is shown in Figs. 4(A) and (
This will be explained with reference to B). This piezoelectric body 15c is a hollow cylindrical body 17 that is made of a piezoelectric material and has both ends open.

002
1]. On the outer peripheral surface of this cylindrical body 17, a first electrode 18a having a band-like pattern and a continuous annular second electrode 18 located on the first electrode are provided.
b is provided. The first electrode 18a has a periodicity, and includes a large number of electrode pieces that extend in parallel with each other at a predetermined interval and are inclined with respect to the central axis of the cylindrical body 17, with adjacent electrode pieces separated from each other at the ends. It is connected and configured. Further, a third electrode 18c is uniformly attached to the inner peripheral surface of the cylindrical body 17 over almost the entire surface.

When a voltage is applied between the first electrode 18a and the third electrode 18c with the bottom of the piezoelectric body 15c having the above structure fixed, the piezoelectric body 15c rotates slightly in the Θ direction. . In addition, the second electrode 18b and the third electrode 18
When a voltage is applied between the piezoelectric body 15c and the
It extends slightly in the X direction along the central axis. And the first
electrode 18a and second electrode 18b, and third electrode 1
When a voltage is applied between the piezoelectric body 15c and the piezoelectric body 15c, the piezoelectric body 15c rotates and its upper end expands. Next, the operation of the inchworm of the fine movement device having the above structure will be explained with reference to FIG.

[0023] First and second sliders 14a, 14
When b is clamped, first the second piezoelectric body 15
b to release the second slider 14b. In this state, the first electrode 18 of the third piezoelectric body 15c
When a voltage is applied between a and the third electrode 18c, the piezoelectric body 15c rotates slightly, thereby rotating the second slider 14b in the Θ direction. Furthermore, when a voltage is applied between the second electrode 18b and the third electrode 18c, the piezoelectric body 15c extends and displaces the second slider 14b in the X direction. When a voltage is simultaneously applied between the first electrode 18a, the second electrode 18b, and the third electrode 18c, the piezoelectric body 15c rotates and extends, moving the second slider 14b in the Θ direction. and displace it in the X direction. Next, the voltage applied to the second piezoelectric body 15b is released, and the second slider 14b is clamped. Then, by applying a voltage to the first piezoelectric body 15a to release the first slider 14a, and then releasing the applied voltage to the third piezoelectric body 15c, the first slider 14a is
is displaced in the X and (or) Θ directions. By repeating this operation, the inchworm can selectively cause the moving stage attached to it to perform linear motion and rotational motion over a wide range.

[0024] The fine movement device of the second embodiment also has the same effects as the first embodiment. 16a, 16b by adjusting these adjustment screws 16a, 16.
Since it can be freely set by b, it is not necessary to form each part with high precision, and there is also an effect that the device can be manufactured at low cost. In the embodiments described above, parallel springs and elastic arms are used as the elastic bodies for fixing the slider between the guide surfaces, but the present invention is not limited to these, and for example, plate springs or coil springs can also be used.

[0025]

As described above, the fine movement device of the present invention can keep the moving stage provided on the slider fixed without applying a voltage to the piezoelectric body. This results in unstable power supply,
The movement stage does not become unstable due to drift conditions caused by temperature fluctuations in the piezoelectric body, and stable micro-movement is possible over a wide range.

[Brief explanation of the drawing]

FIGS. 1A and 1B are a perspective view and a side view of a fine movement device according to an embodiment of the present invention.

FIGS. 2(C) and 2(D) are a plan view and a front view showing the fine movement device.

FIGS. 3A, 3B, 3C, and 3D are a front view, a side view, a top view, and a bottom view, respectively, showing fine movement devices according to other embodiments of the present invention.

4A and 4B are a perspective view and a developed view of a cylindrical piezoelectric body used in the device shown in FIG. 3;

FIGS. 5A and 5B are a plan view and a side view of a conventional fine movement device.

[Explanation of symbols]

2... Side plate, 5a, 15a... First piezoelectric body, 5b, 15b
...Second piezoelectric body, 5c, 15c...Third piezoelectric body, 6a,
14a...first slider, 6b, 14b...second slider, 7a, 7b...parallel spring, 9a. 9b...clamp, 12a, 12b...arm part, 16a, 16b...adjustment screw

Claims (1)

[Claims] 1. First and second sliders disposed between two guide surfaces so as to be movable along them; and two elastic bodies that elastically press and fix these sliders between the guide surfaces. It is provided with first and second piezoelectric bodies that are independent of each of these elastic bodies and capable of releasing the elastic pressure of the elastic body, and a third piezoelectric body that interconnects and integrates both the sliders. Microtremor device.