JPH04142782A - Fine movement 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] [Industrial Application Field] The present invention relates to a fine movement mechanism, and particularly to a fine movement mechanism that is optimal for ultra-precision processing, semiconductor manufacturing equipment, electron microscopes, etc., and for position adjustment on the submicron order. be.

[Conventional technology]

In recent years, in various technical fields, there has been a demand for devices capable of fine position adjustment on the order of submicrons. Typical examples include semiconductor manufacturing equipment such as mask aligners and electron beam lithography equipment used in the manufacturing process of LSIs (Large Scale Integrated Circuits) and VLSIs. These devices require fine positioning on the order of submicrons, and as the positioning accuracy improves, the degree of integration increases, making it possible to manufacture high-performance products. Such fine positioning is necessary not only for the semiconductor manufacturing equipment mentioned above, but also for various high-magnification optical devices such as electron microscopes and ultra-precision processing equipment, and improving its accuracy will improve biotechnology, space development, etc. It will also greatly contribute to the development of cutting-edge technology.

Here, a conventional fine movement mechanism that performs fine positioning will be explained with reference to the drawings. Figure 4 is a side view of the conventional fine movement mechanism.
FIG. 5 is a sectional view taken along the line V-V in FIG. 4. In the figure, reference numeral 1 denotes a fixed part formed as a rigid body, which is fixed by appropriate means.

Reference numeral 2 denotes a movable part formed as a rigid body. The movable part 2 is arranged facing the fixed part 1 with a required space, and is integrally connected to the fixed part 1 by flat plate-shaped elastic parts 3 and 4 at both ends. has been made into The fixed part 1, the movable part 2, and the elastic parts 3, 4 have a predetermined thickness and width, and the elastic parts 3.4 are positioned parallel to each other.

Reference numeral 5 indicates a protrusion protruding from the fixed part 1, 6 a protrusion protruding from the movable part 2, and 7 a piezoelectric actuator disposed between the protrusions 5.6. The piezoelectric actuator 7 is a wedge member 8
between the projections 5.6. When the wedge member 8 is pushed with a force Fl, the distance 11 between the protrusions increases, and the flat elastic members 3 and 4 are displaced by δ in the X direction.

As a result, the reaction force F2 of the flat elastic members 3 and 4 acts on the piezoelectric actuator 7, and the piezoelectric actuator 7
．． It is fixed between 6 and 6.

The force F2 that fixes the piezoelectric actuator 7 is generated by the elastic member 3
, 4 in the X direction in FIG. 4 is expressed by the following equation.

F 2 = k·δ (1) In this state, when a predetermined voltage is applied to the piezoelectric actuator 7, it stretches and the elastic member 3°4 deforms by the amount of displacement U. In other words, a fine movement mechanism for displacing the movable part 2 by U is configured.

As described above, the reason why the piezoelectric actuator 7 is mounted between the protrusion 5 and the protrusion 6 using the wedge member 8 is that the piezoelectric actuator 7 can be easily replaced while giving a preload (fixing force F2) to the piezoelectric actuator. This is to ensure that.

[Problem to be solved by the invention]

When a displacement amount U is generated in the fine movement mechanism, if it is desired to further increase the displacement amount by applying a voltage to the piezoelectric actuator unitar, an excessive stress is applied to the elastic member 3.4 in the above configuration. In order to reduce excessive stress, it is necessary to reduce the thickness t2 of the flat elastic member 3.4 or increase its length 12. However, the elastic member 3.4
When such morphological changes are made to the elastic member 3.4
The rigidity k of the piezoelectric actuator 7 decreases, and the fixing force F2 of the piezoelectric actuator 7 decreases due to the relationship of equation (1), making it impossible to perform proper fixation.

Next, the displacement amount U of the fine movement mechanism will be explained by comparing the case where the displacement amount U is set to 10 μm and the case where it is set to 100 μm, for example. It is assumed that in both cases the stress occurring in the elastic member 3.4 is the same and at a constant level. In order to satisfy this condition, the plate thickness (t2) and length (12) of the flat plate elastic member in each case are t in the case of 10 μm.
lo+' t100+1 for 10%100μm
! ,. . shall be.

For example, t +o= 1 mm, l 1o=
10 mm.

j+oo=0, 3mrn, 1,. .

= 15 mm, the stress in the two cases becomes almost the same. At this time, assuming that the amount δ of the tightening by the wedge member 8 is constant, and comparing the force F2 of the pressing force of the piezoelectric actuator tough, the one for the displacement amount U of 100 μm has a lower rigidity k, compared to the one for the displacement of 10 μm. Approximately 1/100 of the pressure becomes a force. In this way, by using the wedge mechanism and increasing the displacement amount (stroke) of the fine movement mechanism, the piezoelectric actuator 7
Even if you try to fix it, the fixing force will be weak and it will be impractical.

Another possible method for fixing the piezoelectric actuator tough of the fine movement mechanism is to use an adhesive. but,
The method using adhesive has the drawback that it is difficult to replace the piezoelectric actuator and maintenance is poor.

In addition, in the fine movement mechanism formed to produce a large displacement, before the piezoelectric actuator is assembled, two rigid parts, the fixed part 1 and the movable part 2, are connected by flat elastic members 3 and 4 with very low rigidity. Because of this structure, the rigidity of the entire mechanism is low, making it difficult to handle, and the flat elastic member is often deformed during assembly, resulting in defects. However, in order to utilize this effect, the piezoelectric element may be bonded.

An object of the present invention is to provide a fine movement mechanism designed to fix a piezoelectric actuator with a wedge mechanism or adhesive, and to increase the amount of displacement of a movable part, to ensure the fixation of the piezoelectric actuator, and to provide a fine movement mechanism designed to fix the piezoelectric actuator with a wedge mechanism or adhesive, etc., and to ensure the fixation of the piezoelectric actuator. The object of the present invention is to provide a fine movement mechanism that has increased mechanical rigidity and is easy to handle during assembly.

[Means to solve the problem]

In order to achieve the above object, the fine movement mechanism according to the present invention has a first rigid body that is a fixed part and a second rigid body that is a movable part, and the first rigid body and the second rigid body are connected to a first elastic body. Connect with parts,
In a fine movement mechanism in which a piezoelectric element that provides displacement is fixed between a first rigid body and a second rigid body by a fixing means, a second elastic member is provided in parallel with the piezoelectric element, and the second elastic member is provided in parallel with the piezoelectric element. It is characterized in that the first and second rigid bodies are connected by a member.

In the fine movement mechanism according to the present invention, in the above configuration, the first and second elastic members can be flat elastic members.

In the fine movement mechanism according to the present invention, in the above configuration, the first elastic member can be an elastic member having an elastic hinge.

In the fine movement mechanism according to the present invention, in the above configuration, a member having a lever mechanism using an elastic hinge can be used instead of the first elastic member.

Further, in each of the above configurations, the fine movement mechanism according to the present invention has the following features:
The fixing means may be a wedge mechanism.

[Effect]

In the fine movement mechanism according to the present invention, when the piezoelectric element is fixed by using a wedge mechanism or the like between the protrusion of the fixed part and the protrusion of the movable part, the second elastic member is moved in the direction of extension of the piezoelectric element. The first elastic member is arranged in parallel to connect the two protrusions, thereby increasing the rigidity and compensating for the low rigidity of the first elastic member. Therefore, despite the low rigidity of the first elastic member that serves as a movement guide, sufficient fixing force for the piezoelectric element is ensured, and the rigidity of the fine movement mechanism is increased before the piezoelectric element is attached. To facilitate its handling. Elastic members having various structures can be used as the first elastic member.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side view showing a first embodiment of the fine movement function according to the present invention. In FIG. 1, substantially the same elements as shown in FIG. 4 are designated by the same reference numerals. The structure of the fine movement mechanism according to the present invention is basically the same as the structure of the conventional fine movement mechanism described above, and will be summarized below.

In Fig. 1, 1 is a fixed part, 2 is a movable part, and fixed ff1l
Both of the movable part 2 and the movable part 2 are formed as rigid bodies. The fixed part 1 is attached to a fixed wall (not shown) or the like and does not move. The movable part 2 is movable while maintaining a parallel relationship with the fixed part 1. The fixed part 1 and the movable part 2 are coupled by elastic members 3 and 4 located at both left and right ends in FIG. 1, and the elastic members 3 and 4 are flat coupling members. The fixed part 1, the movable part 2, and the elastic members 3 and 4 are integrally formed, and a space is formed in the center. Protrusions 5, 6 are formed on each of the fixed part 1 and the movable part 2, and a piezoelectric actuator 7 and a wedge member 8 are arranged between the protrusions 5, 6. The piezoelectric actuator 7 is mounted between the protrusions 5, 6 using a wedge mechanism. The above configuration is as explained in FIG. 4.

Second elastic members 9 and 10 are further provided to the fine movement mechanism having the above configuration. A second elastic member 9.10 is provided in parallel between the projections 5 and 6 on both sides of the piezoelectric actuator tube. In the illustrated state, the length between the protrusions 5.6 (the length of the second elastic member 9.10) is 11. The second elastic member 9.10 extends at the same time as the piezoelectric actuator 7 extends. Therefore, assuming that the stiffness of the second elastic members 9 and 10 is 2, this stiffness is set to be lower than the stiffness of the piezoelectric actuator 7 itself. With this setting, as shown in the following equation, when the piezoelectric actuator 7 extends, a displacement U can be transmitted to the movable part 2 of the fine movement mechanism.

In the above equation, UO is the amount of displacement generated by the piezoelectric actuator 7 when no load is applied, k is the rigidity of the piezoelectric actuator tough, and F is
2 is the rigidity of the elastic members 9 and 10.

A wedge member 8 is disposed between the piezoelectric actuator 7 and the protrusion 5, and the wedge member 8 is pushed in to generate a fixing force F2 for fixing the piezoelectric actuator 7. When the wedge member 8 is pushed in, the second elastic members 9 and 10
The length of 11 increases.

If the amount of deformation occurring in the elastic members 3 and 4 at this time is δ, then
The fixing force F2 of the piezoelectric actuator tough is expressed by a quadratic equation.

F2 = k ・ δ+ to 2 ・ δ ・ ・ ・
(3) In the above equation, k is the rigidity of the elastic member 3.4 as described above. Note that in this relationship, all parts other than the elastic member are assumed to be completely rigid bodies.

The rigidity of the elastic members 3 and 4 becomes extremely small as the displacement of the mechanism, that is, the displacement U between the fixed part 1 and the movable part 2 increases, so the degree of contribution to the fixing force F2 becomes small. Regarding the rigidity of the elastic members 9 and 10 of 2, even if this is set to be very large, displacement will occur due to the piezoelectric actuator 7 based on the relationship of equation (2) above, and in terms of stress, it will be There is no problem because it is in the direction of extension.This allows the fixing force F2 of the piezoelectric actuator tough to be increased, and the space between the protrusion 5 of the fixed part 1 and the protrusion 6 of the movable part 2 of the fine movement mechanism is stabilized. Can be installed.

Further, the rigidity of the fine movement mechanism before the piezoelectric actuator 7 is attached can be increased by the second elastic member 9.10. Therefore, the problem of erroneous deformation of the elastic member 3.4 during assembly is reduced, which greatly contributes to reducing manufacturing costs. Naturally, since the piezoelectric actuator 7 is mounted using the wedge member 8, the piezoelectric actuator 7 can be easily replaced and maintainability is maintained at a high level. Note that to utilize this effect, the piezoelectric actuator may be fixed with an adhesive or the like. That is, fixing of the piezoelectric actuator is not limited to the wedge mechanism.

FIG. 2 shows a second embodiment of the fine movement mechanism according to the present invention. In FIG. 2, the same elements as those shown in FIG. 1 are given the same reference numerals. The only difference from the previous embodiment is the configuration of the elastic member 3.4. In this embodiment, an elastic member 30 having elastic hinges 31 and 32 at both ends is used instead of the elastic member 3, and an elastic member 40 having elastic hinges 41 and 42 at both ends is used instead of the elastic member 4. .

In this embodiment as well, the second elastic members 9 and 10 are provided in parallel on both sides of the piezoelectric actuator tube, so that the same effect as in the first embodiment is produced. As is clear from this example,
The elastic members 3 and 4 can have any shape.

FIG. 3 shows a third embodiment of the fine movement mechanism according to the present invention. In this embodiment, instead of the flat elastic member 4 in the configuration of the first embodiment, three elastic hinges 43, 44.
45, and a member 60 connected to the elastic hinge 44 is used in place of the protrusion 6 formed on the movable part 2. The mechanism formed by the member 60 is a mechanism that uses a simple lever principle, and according to this mechanism, the displacement generated in the piezoelectric actuator 7 is calculated as (distance between the elastic hinges 43 and 45)/(distance between the elastic hinges 43 and 45). 44 distances).

Therefore, this embodiment has the advantage that, in addition to the effects achieved in each of the embodiments described above, it is possible to realize a larger stroke as the displacement of the fine movement mechanism.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by reducing the rigidity of the first elastic member that connects the rigid body on the fixed part side and the rigid body on the movable part side, the displacement of the fine movement mechanism can be reduced by, for example, 100 μm.
Even with a fine movement mechanism as large as m, since the second elastic member that connects the rigid body on the fixed part side and the rigid body on the movable part side is provided in parallel with the piezoelectric actuator, installation using a wedge member is not possible in the piezoelectric actuator in the mechanism. The piezoelectric actuator can be fixed securely, and other methods such as using adhesives can increase the rigidity of the previous mechanism, making it easier to handle during assembly. .

Figure 2 is a side view of the second embodiment, Figure 3 is a side view of the third embodiment.
FIG. 4 is a side view of the conventional fine movement mechanism, and FIG. 5 is a sectional view taken along the line V-V in FIG. 4.

[Explanation of symbols]

1...Fixed part 2...Movable part 3.4...First elastic member 5.6...protrusion 7・・・・− 8・・・・・ 9, 10・ 30.40 ４６　・・・ ・Piezoelectric actuator ・Wedge member ・Second elastic member ・Elastic member with elastic hinge ・Components with a lever mechanism

Claims (5)

[Claims] (1) It has a first rigid body that is a fixed part and a second rigid body that is a movable part, the first rigid body and the second rigid body are connected by a first elastic member, and the first rigid body and the second rigid body are connected to each other by a first elastic member. In a fine movement mechanism in which a piezoelectric element that causes displacement between rigid bodies is fixed by a fixing means,
A fine movement mechanism, characterized in that a second elastic member is provided in parallel to the piezoelectric element, and the first and second rigid bodies are connected by the second elastic member. (2) The fine movement mechanism according to claim 1, wherein the first and second elastic members are flat elastic members. (3) The fine movement mechanism according to claim 1, wherein the first elastic member is an elastic member having an elastic hinge. (4) The fine movement mechanism according to claim 1, wherein a member having a lever mechanism using an elastic hinge is used in place of the first elastic member. (5) The fine movement mechanism according to any one of claims 1 to 4, wherein the fixing means is a wedge mechanism.