JPS63238493A - Moving mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a moving mechanism suitable for use, for example, in initializing the probe of a scanning tunneling microscope.

[Conventional technology]

For example, in a scanning tunneling microscope, it is necessary to bring the probe close to the sample at an extremely small distance (approximately 10A order), but the movement mechanism for this purpose has conventionally been
A movement mechanism using a piezoelectric actuator is used. Figures 4(a) and ('b) are, for example, U.S. Pat.
43.993, in which A is a moving body and B is a guide portion of the moving body. The moving body A has two parallel horizontal lower arms 1 and upper arms 2, and a vertical (two directions) central arm 3.
This H-body is provided with a head arm 4 extending upward from the upper arm 2, and a probe 5 is attached to the tip of the head arm 4. Each of these arms 1~
4 is a telescoping arm made up of a piezoelectric actuator. The guide part B has two parallel guide grooves 6.7,
One end leg portions of arms l and 2 are engaged with guide groove 6, and 1. The other end legs of the arms 1 and 2 are engaged with the guide groove 7.

In this configuration, when a negative voltage is applied to the piezoelectric actuator of the lower arm 1 and a positive voltage is applied to the piezoelectric actuator of the upper arm 2, the upper arm 2 is extended and the left and right legs are pushed to the bottom of the guide groove 6.7. Fixed by pressure, the lower arm 1 is contracted and the engagement between the left and right legs and the guide grooves 6.7 is loosened. Next, a negative voltage is applied to the piezoelectric actuator of the center arm 3 to cause it to contract, and then a voltage opposite to the above is applied to the piezoelectric actuators of the lower arm 1 and the upper arm 2 with a slightly different timing. The legs are fixed in the guide grooves 6.7 and the legs of the upper arm 2 are released. Next, when the piezoelectric actuator of the central arm 3 is unloaded, the movable body A slightly moves in the direction of the illustrated arrow by the amount of contraction of the central arm 3 described above. By repeating this sequence, the moving body A can be moved in the shape of an inchworm. The head arm 4 is used for ultra-fine seed motion of the probe 5, and when initially setting the distance of the probe 5 to the sample,
With this head arm 4 extended, the movable body A is roughly moved toward the sample, and when a tunnel current is detected, the coarse movement of the movable body A is stopped. [Problem to be solved by the invention] In this way, the moving body A moves by expanding and contracting the three piezoelectric actuators according to a predetermined sequence, but the maximum displacement of commercially available piezoelectric actuators is 2.
Since the diameter is approximately 0 μm, the machining accuracy of the guide groove must be extremely high, and the leg of the arm that moves during movement will be in a state of sliding within the groove, so the movement cycle will be shortened. There is a problem in that when the height is increased to move at high speed, the amount of movement becomes unstable. Furthermore, since the moving body A is on one side of the probe 5,
There is a problem in that thermal expansion strain (displacement) due to heat generated by the piezoelectric actuator directly acts on the probe 5.

This invention was made to solve the above problem.
The machining accuracy is one that can be easily obtained with current technology, and it is also capable of stable high-speed movement, and can eliminate the effects of thermal expansion distortion caused by the heat generated by the piezoelectric actuator on the object to be moved, such as the above-mentioned probe. The purpose is to provide a mechanism.

[Means to solve the problem]

In order to achieve the above object, this invention has two guide plates erected in parallel on a base with their guide surfaces facing each other, upper and lower leaf springs horizontally parallel, and fixed on the base. a one-dimensional inch worm supported by a parallel spring mechanism and arranged perpendicularly between the guide surfaces of the guide plate with a predetermined gap between the two guide surfaces to support the moving object; The one-dimensional inch worm has a left-right symmetrical structure, including an extensible part into which a moving piezoelectric actuator is press-fitted in an upward and downward direction, and an upper and lower part which continues vertically into the elastic part and into which a piezoelectric actuator for clamping is press-fitted upwardly and downwardly. The clamp part has a clamp element having a clamp surface part of a predetermined area that can be clamped to the corresponding guide plate, and a clamp element that amplifies the extensional displacement of the piezoelectric actuator for clamping to the clamp element. The clamp element is configured to include a portion that elastically drives the clamp element outward by transmitting the signal.

[Effect]

In this invention, since the extension displacement of the piezoelectric actuator for clamping is greatly amplified, the required machining accuracy is normally easily achievable, and the moving part is not in contact with the guide plate during movement. Therefore, even if the movement cycle is increased or the amount of movement per time is reduced, the movement can be performed minute by minute with good reproducibility, and high-speed movement can be achieved. In addition, since the clamp part is continuous above and below the expandable part, the thermal expansion strain caused by the heat generated by the piezoelectric actuator is canceled out in the central part, so that if the support to be moved is connected to the central part, the movement can be made. The above thermal expansion strain does not act on the object.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment in which the present invention is applied to a coarse movement mechanism of an STM probe. In both figures, 10
21.21 is a vibration isolation table that absorbs vibrations, and 21.21 is a guide plate that runs parallel to the vibration isolation table 10 at a predetermined interval. . 3
0 is a one-dimensional inchworm (hereinafter referred to as
The movable body (shown enlarged in FIG. 2) is vertically supported by a parallel spring mechanism 22, and is placed between the guide surfaces of parallel guide plates 21 and 21, with both sides thereof being a guide surface. They are held so as to be separated by a small predetermined clearance δ. This parallel spring mechanism 22 connects two horizontally oriented leaf springs 22A, 22A with one end of each, and connects the other end with a base plate 23A vertically erected on the vibration isolating table 10. It has a shape consisting of a connecting plate portion 23B, and the connecting plate portion 23B is fixed to a proper position on the rear surface of the movable body 30 via a mounting member 24. Furthermore, a "shaped mounting base 26 that pairs with the mounting member 24 is fixed to the front surface of the movable body 30 so that its base surface is horizontal, and at the tip of the base surface,
A three-dimensional fine movement drive mechanism 27 that holds the probe 25 vertically downward is mounted and fixed.

The movable body 30 is a cutout block-like body with a bilaterally symmetrical structure, and is formed using electrical discharge machining technology (accuracy of about 5 μm), and as shown in FIG. It consists of a clamp part 60 that is continuous with a part 50 in between.

In addition, in FIG. 3, for convenience of explanation, the movable body 30 is shown in an unclamped state and floating in the air.

The stretchable part 40 consists of two parallel elastic stretchable parts 41.41 bridging the upper and lower boundary parts 50.
Reference numeral 41 defines a storage portion 43 that stores a piezoelectric actuator 42 for movement, and the piezoelectric actuator 42 has one end surface in contact with the upper surface of the pressure receiving portion 50A protruding from the lower boundary portion 50, and Fixing screw 4 that screws in and penetrates
4 is housed in the storage section 43 under a pressing force via a ball 45 engaged with the other end surface. The elastic expansion/contraction part 41 is integrally continuous with the upper boundary part 50 via a vertically oriented parallel spring part 46 provided at one end, and continues integrally with the upper boundary part 50 via a horizontally oriented parallel spring part 47 provided at the other end. 50 and is integrally continuous with the side surface of the pressure receiving portion 50A. The lower clamp part 60 is connected to the lower boundary part 5 via the bottom side or a gap.
0, and an outer U-shaped portion 63 that covers the opening of the inner U-shaped portion 62. Both U-shaped portions 62 and 63 act as piezoelectric actuators for clamping. The pressure receiving portion 64 receives the displacement force of 66 and the pressure receiving portion 6
The piezoelectric actuator 66 is press-fitted between both pressure receiving parts 64. 67 is a fixing screw, and 6th is a ball. The ends of the transmission portion 65 of the inner U-shaped portion 62 and the outer U-shaped portion 63 are U-shaped, and the outer hinge portion 69 of the elastic hinge mechanism portion 71 has an outer hinge portion 69 and an inner hinge portion 70 that are parallel to each other. It is integrally continuous with the inner hinge part 70. This elastic hinge mechanism section 71 has an elastic amplification mechanism section (hinge section).
72 are integrally continuous, and 73 is a clamp element, which has a clamp surface part 73a of a predetermined area slightly protruding from the other parts on the outer surface side, and has a free end close to and opposite to the elastic hinge mechanism part 71, It is provided in parallel with the hinge portion 72 and integrally continues with the hinge portion 72 to the boundary portion 50 via a vertical parallel spring portion 74 . The outer hinge portion 69, the inner hinge portion 70, and the hinge portion 72 have elastic hinges (the thinnest southern parts) formed by making the inner and outer surfaces arc concave. The upper clamp part 60 also has the same structure as the lower clamp part 60. In addition, 75 is the mounting member 2
4 and the mounting base 26 are screw holes formed in the lower boundary portion 50. Also, 3
The dimensional fine movement mechanism 27 has a probe holder driven by a piezoelectric actuator that expands and contracts in the X-axis direction, a piezoelectric actuator that expands and contracts in the Y-axis direction, and a piezoelectric actuator that expands and contracts in the Z-axis direction. It can be displaced in units of 5 μm.

Next, the operation of this embodiment will be explained.

First, the clamping operation of the upper clamp section 60 will be explained. When a predetermined positive voltage is applied to the clamping piezoelectric actuator 66, the piezoelectric actuator 66 expands in the vertical direction (Z-axis direction) by an amount corresponding to the voltage value. Due to the expansion of the piezoelectric actuator 66, the U-shaped portions 62 and 6
A pressing force is applied to the pressure receiving legs 64 of No. 3 in a direction to relatively separate them, and a tensile force is applied to both transmission legs 65 in opposite directions in the Z-axis direction. For convenience of explanation, suppose that the U-shaped portion 63 is displaced downward with respect to the figure, and the outer hinge portion 69
The thinnest inner α portion rotates around the elastic hinge H of the inner hinge portion 70, and along with this rotation, the thinnest southern β portion of the hinge portion 72 rotates, and the clamp member 73 rotates this in the direction of the arrow shown in the figure. A rotational force acts to cause the object to rotate. The lamp element 73 tends to be rotated due to the rotational force, but due to the action of the parallel spring portion 74, the components in the biaxial directions are eliminated and the components in the lateral direction (
Only the component in the Y-axis direction) acts, and the left and right clamp members 73 are displaced toward the guide +7i21.21, respectively, with their clamp surfaces 73a parallel to the Z-axis direction, and the guide plates 21.21 This results in a pressure welding engagement (clamp). The amount of displacement of the clamp element 73 at this time is determined by the ratio of the distance IJcx to the distance Hβ, and a displacement amount that is about three times the amount of displacement of the piezoelectric actuator 66 can be easily obtained.

When the application of the voltage is stopped, the outer hinge portion 69, inner hinge portion 70, and hinge portion 72 are elastically displaced and return to the illustrated positions, and the left and right clamp members 73 are separated from the guide plate 21 with which they were frictionally engaged. The clamp will be released.

As mentioned above, the maximum displacement amount of the piezoelectric actuator 66 is about 20 μm, so if the magnification of the displacement is 3 times, it will be 6 times 120 μm because of the symmetrical structure.
becomes. Since the machining accuracy that can be easily obtained at present is about 30 μm, considering the clearance δ, the minimum displacement of the clamp element 73 is required to be about 40 μm, but the above embodiment fully satisfies this requirement. be able to.

When the upper clamp part 60 performs the above-mentioned clamping operation, if the clamp member 73 is likened to a human hand, the movable body 30 will be in a state where it is pulling the left and right guide plates 21 with both hands. There is a left-right shift in the part,
Although there is a possibility that the movable body 30 may engage with either of the guide plates 21, in this embodiment, the entire movable body 30 is elastically supported by the parallel spring mechanism 22. The other parts except the upper left and right clamps are guide plates 21 and 21.
It becomes a non-contact state.

Next, the expansion/contraction operation of the expansion/contraction section 40 will be explained.

It is now assumed that the upper piezoelectric actuator 66 is expanded and the upper clamp section 60 is performing the above-described clamping operation. In this state, when a predetermined positive voltage is applied to the moving piezoelectric actuator 42 and it is expanded, a Z
Since a force directed in the axial direction acts, the horizontal parallel spring portion 47
Due to the elastic displacement, the left and right elastic expansion/contraction parts 41 expand in the Z-axis direction. When the voltage application is stopped, the piezoelectric actuator 42 contracts to the state before voltage application, so that the parallel spring portion 47 returns to the illustrated state due to its elasticity. Conversely, when a predetermined negative voltage is applied to the piezoelectric actuator 42, the piezoelectric actuator 42 contracts, and the left and right elastic tensioning parts 41 also become parallel spring parts 47.
It contracts in the Z-axis direction due to the displacement of .

Next, when moving the moving body 30 of the embodiment downward, the following sequence is executed. Note that the moving body 30
The piezoelectric actuator 66 of the lower clamp part 60 receives a positive voltage, and the clamp part 60 moves towards the left and right guide plates 21.
Assume that the clamp is engaged.

A negative voltage is applied to the moving piezoelectric actuator 42 to contract the extensible part 40, and a positive voltage is applied to the piezoelectric actuator of the upper clamp part 60 to perform a clamping operation, and the piezoelectric actuator of the lower clamp part 60 is is unloaded, the clamp is released, and the voltage applied to the moving piezoelectric actuator 42 is removed. This results in
The movable body 30 as a whole moves downward by the amount of contraction of the telescoping section 40 .

By repeating this sequence, the movable body 30 moves without sliding on the guide plate 21, so that it can be moved an arbitrary distance in the vertical direction of the Z-axis.

In this embodiment, since the clamp part 60 is continuous above and below the extensible part 40, the deformation (thermal expansion strain) of the movable body 30 due to the heat generated by the expansion and contraction of the piezoelectric actuator 66 occurs at the center of the movable body 30. Since the mounting base 26 that supports the three-dimensional fine movement mechanism 27 is connected to the lower boundary part 50, the three-dimensional fine movement mechanism 27 is hardly affected by the deformation caused by the heat, and therefore If the moving mechanism of this embodiment is used, the three-dimensional fine movement mechanism 27 can be moved in the Z-axis direction with extremely high precision, and is extremely suitable as a coarse movement mechanism of a scanning tunneling microscope.

In the above embodiment, the present invention is applied to a coarse movement mechanism of an STM, but the present invention is not limited to this.

〔Effect of the invention〕

As explained above, this invention eliminates the need for high-precision machining of component parts, so manufacturing costs can be sufficiently reduced compared to conventional methods, and when moving, the moving parts are guided. Since it moves without friction with the plate, stable high-speed movement is possible.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention, and FIG.
The figure is a nn arrow view in the above embodiment, Fig. 3 is a front view of the one-dimensional Ichi worm in the above embodiment, and Fig. 4 (a
) and middle) are diagrams showing a conventional moving mechanism. 21-clamp plate, 22-parallel spring mechanism, 30-i
Dimensional inchworm, 40--extensible part, 41--elastic extensible part, 42-- piezoelectric actuator for movement, 50-- boundary part, 60-- clamp part, 61-- displacement transmission part,
66--piezoelectric actuator for clamp, 71--elastic hinge mechanism section, 72--elastic amplification mechanism section, 73--clamp element, 73a--clamp surface section.

Claims (3)

[Claims] (1) 2 erected in parallel on the base with the guide surfaces facing each other
A book guide plate has upper and lower leaf springs that are parallel to each other in a horizontal direction, and is supported by a parallel spring mechanism fixed on the base, and supports a moving object between the guide surfaces of the guide plate. A one-dimensional inchworm is arranged vertically with a predetermined gap between the surfaces, and the one-dimensional inchworm has a left-right symmetrical structure, and a piezoelectric actuator for movement is press-fitted vertically. It has an extendable part and an upper and lower clamp part that is continuous with the extendable part and into which a piezoelectric actuator for clamping is vertically press-fitted, and the clamp part has a predetermined area that can be clamped and engaged with the corresponding guide plate. A moving mechanism comprising a clamp element having a clamping surface portion and a portion that amplifies and transmits the extensional displacement of the clamping piezoelectric actuator to the clamp element to elastically drive the clamp element outward. (2) Parallel two parts in which the elastic part bridges between two boundary parts where the clamp parts are continuous at a predetermined distance in the downward direction and defines a housing part into which the piezoelectric actuator for movement is press-fitted. A moving mechanism comprising an elastic stretchable section of a book, the elastic stretchable section having a vertical parallel spring section at its upper end and a horizontal parallel spring section at its lower end. (3) a displacement transmitting section in which the clamp section defines a vertically parallel spring section continuous to a boundary section that borders the clamp section with the telescopic section; and a housing section into which a piezoelectric actuator for clamping is press-fitted; the displacement transmitting section; an elastic hinge mechanism that is integrally continuous with and converts the vertical displacement of the displacement transmitting section into rotational displacement; and an elastic hinge mechanism that is integrally and continuous with the parallel spring section that amplifies the rotational displacement of the elastic hinge mechanism. Claims characterized in that the clamping element has an elasticity amplifying mechanism section that transmits the elasticity to the clamping element, and the clamping element is a clamping element whose one end that is integrally continuous with the boundary section via the parallel spring section is a free end. The moving mechanism according to the range 1 or 2.