JP2935231B2 - Feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed device, and more particularly to a feed device for feeding a movable body to a fixed side.

[0002]

2. Description of the Related Art For example, STM (scanning tunnel microscope)
Is a step feeder using inertia. In the feed device utilizing inertia, for example, a probe mounting base for supporting a probe is fed by a driving leg made of a piezoelectric body. The drive leg slowly expands, contracts or shears so that the probe mounting base does not slip, and the mounting base is sent only to a portion corresponding to the amount of deformation. Then, after moving the movable part, the drive leg is rapidly piezoelectrically deformed and returned. At this time, the mounting base hardly moves due to its inertia, and the driving legs of the piezoelectric body make a sliding frictional movement with respect to the mounting base or the fixed side.

Another conventional feeder is disclosed in Japanese Patent Application No. 62-109133 (JP-A-63-274894).
As suggested by: This feeder has two types of drive legs, and while the movable body is supported by the first drive leg, the second drive leg is contracted and sheared in the feed direction, and then the second drive leg is extended. Thus, the movable body is supported, and the operation of contracting and shearing the first drive leg is repeated.

[0004]

A drawback of the conventional feed device utilizing inertia is that when the drive leg returns to its original shape, its tip makes a sliding frictional movement with respect to the mounting base or the fixed side. In addition, although a hard substance such as sapphire is used for the material of the tip of the drive leg, there are many problems in view of durability.
The STM used on a large sample stage has a drawback that the surface of the sample is damaged by the sliding frictional motion of the drive leg.

On the other hand, Japanese Patent Application No. 62-109133 (Japanese Patent Application Laid-Open No. 63-274894) proposed by the present applicant has been proposed.
The feed device according to item (1) does not damage the surface of the sample because the drive leg has no sliding frictional motion. However, this device requires two sets of drive legs to alternately support the movable body, and thus has a disadvantage in that the number of drive legs increases. In addition, since the mounting positions of the two types of drive legs are different, there is a severe requirement for the flatness of the fixed side or the movable side that comes into contact with the tip of the drive leg. Therefore, in order to realize reliable feeding, a stacked piezoelectric body is used, and a gap between the fixed side or the movable body when the drive leg is contracted is reduced by 0.5.
It was necessary to make it more than μm. Therefore, there is a disadvantage that a large number of driving legs made of piezoelectric materials stacked in multiple layers are required, which increases the cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is intended to prevent a driving leg from sliding frictional movement with respect to a fixed side or a movable body and to reduce the number of driving legs. It is another object of the present invention to provide a feeding device that performs reliable feeding even when a gap between the fixed leg and the movable body when the driving leg is contracted is small.

[0007]

According to the present invention, the movable body is supported on a fixed side by a drive leg which expands and contracts in a longitudinal direction and deforms in a feed direction and a reverse direction. Momentarily contracts the tip of the drive leg away from the fixed side or the movable body, deforms the drive leg in the feed direction or the opposite direction during the minute time when the movable body is floating, and extends the drive leg. Then, after the movable body is supported by the drive leg, the drive leg is deformed in the reverse direction or the feed direction at a speed that the movable body can follow.

[0008]

Therefore, the drive leg is contracted so that its tip is separated from the fixed side or the movable body and the movable leg loses its support by the drive leg and the drive leg is moved in the feed direction or the reverse direction. Is transformed into Then, the drive leg is extended, and after the tip end contacts the fixed side or the movable body and the movable body is supported by the drive leg, the drive leg is slowly moved in the reverse direction or the feed direction at a speed that the movable body can follow. By deforming, the movable body is sent to the fixed side by a distance equal to the deformation amount.

[0009]

1 to 3 show a feeder according to a first embodiment of the present invention.
1 on the fixed base 11 to the left in FIG. The movable body 10 has at least a pair of drive legs 12 at its lower part. Drive leg 12
As shown in FIG. 2, is composed of a laminate of a shear deformation plate 13 and an expansion deformation plate 14, and has a structure in which an insulating layer 15 is interposed between the two. Alternatively, as shown in FIG. 3, a structure in which two shear deformation plates 13 and two elastic deformation plates 14 are combined may be used. In this case, the insulating layer 15
Can be omitted, and the displacement can be increased by further laminating.

Next, the feeding operation of the movable body 10 having the driving legs 12 shown in FIG. 2 or 3 will be described with reference to FIGS. In a stationary state, the movable plate is supported by extending the telescopic plate 14 of the drive leg 12 (FIG. 1A). Next for a short time
The elastic plate 14 is contracted for t (FIG. 1-B). Then, the movable body 10 loses its support and starts free fall. Drive leg 1
While the movable body 10 is floating with the distal end of the movable member 2 being separated from the surface of the fixed base 11, the shearing deformable plate 13 is sheared as shown in FIG. Then, the drive leg 12 lands (FIG. 1-D). Next, the shear deformation plate 13 is slowly sheared in a direction opposite to that of FIG. 1C so that the tip of the drive leg 12 in contact with the fixed base 11 does not slip. Then, the movable body 10 is sent by a distance equal to this deformation amount (FIG. 1-E).

When it is desired to stop by one step of movement, the elastically deformable plate 14 is contracted (FIG. 1-F),
The deformation of No. 3 is made zero (FIG. 1-G), and the elastically deformable plate 14 is extended to return to the state of FIG. 1-A. On the other hand, when moving continuously, it is sheared from FIG. 1-F to the state of FIG. 1-C. Thereafter, the operation is repeated in the order of C, D, E, F, and C in FIG. FIG. 4 shows a timing chart of the voltage Ve applied to the elastically deformable plate 14 and the voltage Vs applied to the shearing deformable plate 13 when moving and stopping at two steps. In FIG. 4, A to G correspond to the respective steps in FIG.

The movable body 10 falls freely during Δt when its driving leg 12 is contracted. However, since Δt is very short, the falling distance is very small. That is, since the movable body 10 has inertia, a change in the height of the movable body 10 is very small as compared with the amount of deformation of the elastic plate 14. Specifically, the distance h at which the movable body 10 naturally falls is given by the following equation.

H = (1/2) g (△ t) ^{2 where} g = 9.8 (m / s ² ) is the gravitational acceleration. △
If t = 10 μs, h = 0.5 nm. Δt =
Even if it is 100 μs, h = 50 nm. Assuming that the expansion and contraction of the expansion and contraction plate 14 is 500 nm, the driving leg 12 does not come into contact with the fixed side 11 at the time of the shearing deformation in FIG.

Next, a second embodiment will be described with reference to FIG. In this embodiment, the driving leg 12 is mounted on the fixed side without mounting the driving leg 12 on the movable body 10, and the movable body 10 is fed. If the movable body 10 is sufficiently heavy, the upper fixed plate 18 may be omitted. The movable body 10 is provided between a drive leg 12 including a telescopic deformation plate 14 and a shear deformation plate 13 attached to a lower fixed base 11 and a drive leg 12 having a similar structure attached to an upper fixed plate 18. It is structured to be sandwiched. The upper fixing plate 18 is not allowed to move in the lateral direction. In this embodiment, the leaf spring 19 does not move in the lateral direction.

In order to increase the force for pressing the movable body 10, the weight of the upper fixed plate 18 may be increased, or the force of the leaf spring 19 may be further increased after increasing the own weight. For example, 10
When the upper fixed plate 18 having its own weight of g is pressed with a force of 1 kg weight, the acceleration applied to the upper fixed plate 18 is g (gravitational acceleration).
And the upper fixed plate 1 during Δt = 10 μs
8 is lowered by 50 nm, but a sufficient gap is secured, and the bottom of the drive leg 12 does not come into contact with the movable body 10 while the drive leg 12 on the upper fixed plate 18 side is contracted and sheared. . 10kg when the amount of expansion and contraction is 500nm
When pressed by heavy force, the drive leg 12 comes into contact with the movable body 10 while the elastically deformable plate 14 of the drive leg 12 on the upper fixed plate 18 side is contracted. In such a case, the upper fixing plate 1
8 may be increased in its own weight and its inertia may be increased.

When the mass of the fixed base 11 or the movable body 10 to which the driving leg 12 made of a piezoelectric body is attached is sufficiently larger than the mass of the expansion / contraction plate 14 of the driving leg 12, the amount of deformation of the expansion / contraction plate 14 is free. It becomes a gap for falling. Even when the movable body 10 does not have a sufficient mass ratio with respect to the elastically deformable plate 14, the worst case may be considered under the condition that the position of the center of gravity of the piezoelectric body 14 does not change. A gap of 1/2 is secured at a minimum.

FIG. 6 shows a third embodiment. In this embodiment, the columnar movable body 10 is fed in the axial direction. The movable body 10 is fed by the two driving legs 12 attached to the V-groove portion of the fixed base 11 and the driving legs 12 pressed by the leaf spring 19 via the fixed plate 18. While the elastically deformable plate 14 of the driving leg 12 is contracting, the shearing deformable plate 13 is deformed in the feed direction of the movable body 10, and after the driving leg 12 lands, the shearing deformable plate 13 slowly moves the movable body 10 in the axial direction. I try to send. In this embodiment, the weight of the fixing plate 18 and the spring 1
The relationship of the pressing force 9 is the same as that in the case where the movable body 10 in FIG. 5 is a plate.

Next, a fourth embodiment will be described with reference to FIG. In this embodiment, the direction of polarization of the shear deformation plate 13 of the drive leg 12 is perpendicular to the axis and is set to the circumferential direction, whereby the disk-shaped movable body 10 is fed in the circumferential direction. That is, here, the motor is a motor that rotates the movable body 10. In this case, no fixed base is provided, and the circular leaf spring 19 forms the fixed side. The elastic restoring force of the circular leaf spring 19 is adjusted by the bolt 23. And a circular leaf spring 19
The three fixed legs are supported on the inner peripheral surface at intervals of 120 °.

Next, a fifth embodiment will be described with reference to FIGS. In this embodiment, the drive leg 12 includes two shear deformation plates, an X-direction shear deformation plate 26 and a Y-direction shear deformation plate 27, and these shear deformation plates 26, 27 are combined with an expansion deformation plate 29. It has become so. Accordingly, the movable body 10 can be moved two-dimensionally in the X and Y directions with respect to the fixed base 11. By adjusting the amount of deformation in the X and Y directions, two-dimensional movement in an arbitrary direction becomes possible.

FIGS. 10 and 11 show a sixth embodiment. In this embodiment, the movable body 10 is made circular, and a circumferential shearing plate 28 is further added to the drive leg 12 in addition to the fourth embodiment, so that not only two-dimensional feed but also rotary movement is possible. I have to.

FIGS. 12 and 13 show an embodiment of an STM coarse movement mechanism in which two-dimensional feed and one-dimensional feed are combined. In this embodiment, the movable body 10 is a magnet 3
2 and is supported by a one-dimensional feed mechanism composed of a pair of drive legs 12 while being attracted to a fixed base 11. A probe mounting base 34 is attracted to the distal end side of the movable body 10 via a magnet 33.
The mounting base 34 is a drive leg 1 composed of a two-dimensional feed mechanism.
2. The probe 35 attached to the tip of the mounting table 34 is
The surface shape is detected by contacting the surface of the sample 37 above.

Such a coarse movement mechanism can be mounted on a sample introduction part of a transmission electron microscope, and can be mounted on an electron microscope and an ST microscope.
Combination with M is realized. The shearing plates used for feeding in the X and Y directions are used as scanners in the X and Y directions after reaching a predetermined field of view.

Next, an eighth embodiment will be described with reference to FIG. In this embodiment, an X-direction shearing plate 41 and a Y-direction shearing plate 42 are attached to the lower end of a cylindrical piezoelectric body 40,
The expansion and contraction of the drive leg 12 necessary for driving is performed by two-dimensional movement using the expansion and contraction of the cylindrical piezoelectric body 40. Tip 3
The tube scanner 45 to which 5 is attached is supported by the lower end of the attachment base 34. Then, the mounting table 34 is sent in the Z direction by the drive legs 12 provided on the movable body 10. The drive leg 12 for feeding in the Z direction is pressed by a holding plate 20, and the holding plate 20 is pressed by a bolt 44 via a coil 43.

A tube scanner 45 to which a probe 35 is attached
Is transmitted in the Z direction by the drive leg 12, thereby realizing a three-dimensional coarse movement mechanism. With the tube scanner 45 fixed, the feed mechanism of the third embodiment shown in FIG.
When the probe 35 is attached to the tip, three-dimensional coarse movement with a mechanism for feeding the probe 35 itself in the Z direction, that is, the direction in which the probe 35 approaches the sample 37, is also possible.

Next, a ninth embodiment will be described with reference to FIGS. In this embodiment, the movable body 10 is fed by a cylindrical piezoelectric body 48 shown in FIGS. The cylindrical piezoelectric body 48 is formed into a cylinder having a predetermined thickness, and an inner electrode 49 is provided on the inner peripheral surface thereof as a common electrode continuously at 360 °. On the other hand, the outer electrode 50 is formed on the outer peripheral surface of the piezoelectric body 48 into four parts at 90 ° intervals. With such a cylindrical piezoelectric body 48, it is possible to omit a piezoelectric body that undergoes shear deformation.

As shown in FIG. 16, a cylindrical piezoelectric body 48 having four divided electrodes 50 can be moved in a direction of expansion and contraction and in a lateral direction by a single piezoelectric body 48 as shown in FIG. As shown in FIG. 17, lateral deformation utilizes the fact that the cylinder 48 bends due to expansion and contraction of the side surface of the opposite cylinder. When the cylinder 48 is deformed so that the amount of elongation and the amount of shrinkage on both sides are the same, the elongation and the shrinkage are offset on the central axis, as is apparent from FIG.

FIG. 15 shows an operation in which feed is realized by such a cylindrical piezoelectric body 48 as to perform an action equivalent to deformation in two directions by the elastically deformable plate and the shearing deformable plate.
When the movable body 10 is supported by the outer peripheral portion on the lower end side of the drive leg 12 made of a cylinder as described above, the movable body 10 is vertically Motion.

FIG. 1 shows an embodiment in which such vertical movement is prevented.
8 and FIG. In this embodiment, a conical pin 54 is attached to the bottom of a drive leg 12 made of a cylindrical piezoelectric body 48 via a bottom plate 53.

The principle of operation of the cylindrical piezoelectric body 48 is as shown in FIG. 17, in which the height of the side surface of the cylinder changes when it is bent, but the change in height on the center axis of the cylinder is negligible. small. Therefore, by attaching the pin 54 on the central axis at the bottom of the cylindrical piezoelectric body 48 and supporting the movable body 10 with the pin 54, it becomes possible to realize a feed with very little change in height. 3 to support the movable body 10
More drive legs 12 are required. FIG. 18 shows an operation of feeding the movable body 10 by such a driving leg. In this figure, E, S, and N represent the expansion and contraction of the cylindrical side surface, respectively.
And a state without expansion and contraction.

[0030]

As described above, according to the present invention, the drive leg is contracted instantaneously, the tip of the drive leg is separated from the fixed side or the movable body, and the drive leg is fed during a very short time when the movable body is floating. After the drive leg is extended and the movable body is supported by the drive leg, the drive leg is deformed in the reverse direction or the feed direction at a speed that the movable body can follow. Therefore, no sliding frictional motion occurs when the movable body moves. Therefore, it is possible to realize a feeder that feeds the movable body in one-dimensional or two-dimensional directions without a movement that causes dynamic friction, that is, without a sliding movement. Moreover, since the deformation of the drive leg in the feed direction or the reverse direction is performed while the drive leg is contracted and the movable body loses support, the number of drive legs can be reduced, and
It is possible to reduce a gap between the fixed leg and the movable body when the drive leg is contracted.

[Brief description of the drawings]

FIG. 1 is a front view showing the operation of a first embodiment.

FIG. 2 is an enlarged perspective view of a driving leg. In the drawings after this figure, arrows in the piezoelectric body indicate polarization axes.

FIG. 3 is an enlarged perspective view of a driving leg.

FIG. 4 is a graph showing a feeding operation.

FIG. 5 is an external perspective view of a feeder according to a second embodiment.

FIG. 6 is a longitudinal sectional view of a feeder according to a third embodiment.

FIG. 7 is a plan view of a feeder according to a fourth embodiment.

FIG. 8 is a front view of a feeder according to a fifth embodiment.

FIG. 9 is a side view of the same.

FIG. 10 is a front view of a feeder according to a sixth embodiment.

FIG. 11 is a view taken along line XI-XI in FIG. 10;

FIG. 12 is a plan view of a seventh embodiment.

FIG. 13 is a front view of the same.

FIG. 14 is a longitudinal sectional view of the eighth embodiment.

FIG. 15 is a front view showing a feeding operation of the ninth embodiment.

FIG. 16 is a cross-sectional view showing a drive leg of the feeder.

FIG. 17 is a front view showing a deformation of the driving leg.

FIG. 18 is a front view showing the operation of the feeder of the tenth embodiment.

FIG. 19 is a vertical sectional view of the driving leg.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Movable body 11 Fixed base 12 Drive leg 13 Shear deformation plate 14 Elastic deformation plate 48 Cylindrical piezoelectric body 49 Inner electrode 50 Outer electrode 54 Pin

Claims (1)

(57) [Claims] 1. A movable leg is supported on a fixed side by a drive leg that expands and contracts in a length direction and deforms in a feed direction and a reverse direction. The movable leg is deformed in the feed direction or the opposite direction during a very short time when the movable body is floating, and the movable leg is extended to move the movable body to the movable leg. Wherein the drive leg is deformed in a reverse direction or a feed direction at a speed at which the movable body can follow the support leg.