JP2849158B2 - Fine movement mechanism - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fine movement mechanism used for performing fine positioning or the like.

[Conventional technology]

In recent years, in various technical fields, devices capable of finely adjusting displacement on the order of sub-μm have been demanded. A typical example is a semiconductor manufacturing apparatus such as an LSI (Large Scale Integrated Circuit), a mask aligner used in a manufacturing process of an VLSI, and an electron beam lithography apparatus. In these devices, the sub-μ
Fine positioning on the order of m is required, and as the positioning accuracy increases, the degree of integration increases, and a high-performance product can be manufactured. Such fine positioning is necessary not only in the above-described semiconductor manufacturing apparatus but also in various high-magnification optical devices such as an electron microscope, and by improving the accuracy thereof, advanced technologies such as biotechnology and space development can be used. It greatly contributes to development.

Conventionally, as a mechanism (hereinafter, referred to as a fine movement mechanism) for giving a minute displacement to a device for performing the above-described fine positioning,
One using a so-called pair structure has been proposed. Such a fine movement mechanism will be described with reference to FIG.

FIG. 6 is a side view of a conventional fine movement mechanism. In the figure, x,
y and z indicate coordinate axes. 1 is lower rigid body, 2 is upper rigid body,
Reference numeral 3 denotes a plurality of rotating pairs connecting the lower rigid body and the upper rigid body 2. These rotating pairs will be described later. Reference numeral 4 denotes a projection integrally formed with the lower rigid body 1, and reference numeral 5 denotes an actuator supported by the projection 4. Usually, a laminated piezoelectric element is used as the actuator 5. 6 is the lower rigid body 1
Operating body connected to the upper rigid body 2 via a rotating pair,
Reference numeral 7 denotes a contact point between the actuator 5 and the operating body 6.

Here, the rotating pair 3 will be described with reference to FIG. FIG. 7 is a perspective view of a rotating pair. In the figure, reference numeral 3 denotes a rotating pair, which is formed of a prismatic rigid body. Reference numeral 3a denotes a U-shaped or semi-circular cutout portion, two of which are formed to face each other. 3b and 3c denote rigid portions on both sides of the notch 3a, and 3d denotes a thin portion formed by the two notches 3a. A indicates an axis that passes through the center of the thinnest portion of the thin portion 3d and is parallel to the wall of the thin portion 3d. When the rotation pair 3 fixes one of the rigid portions 3b and 3c, for example, the rigid portion 3b, and applies a force component in the direction of arrow B perpendicular to the axis A to the other rigid portion 3c, the rotation pair 3 rotates around the axis A ( (Small rotation). However, it has high rigidity against other force components and moment components.

Next, the operation of the fine movement mechanism shown in FIG. 6 will be described. When the actuator 5 is excited in a state where the lower rigid body 1 is fixed and is extended in the x-axis direction (leftward in the figure), the operating body 6 slightly rotates clockwise with the contact point 7 as an operation point. For this reason, a force in the x-axis direction (rightward) acts on the upper rigid body 2, and each rotating pair 3 is minutely rotated by this force as described above. As a result, the upper rigid body 2 is translated in the x-axis direction (rightward) in accordance with the force component. Therefore, the table on which the object is placed is fixed on the upper rigid body 2 or the upper rigid body 2
By directly placing an object on itself, the object can be positioned. The magnitude of the translational displacement can be arbitrarily selected by controlling the degree of extension of the actuator 5. Further, the translation in the two-axis direction or the three-axis direction can be obtained by a configuration in which two or three of the illustrated fine movement mechanisms are overlapped and connected.

When this is configured using the rotating pair 3 as in the fine movement mechanism, there is a remarkable advantage as compared with the case using the translation pair. To clarify this advantage, the translation even configuration is briefly described.

FIG. 8 is a perspective view of a translation pair. In the figure, reference numeral 9 denotes a translation pair, which is formed of a prismatic rigid body. 9a is a concave notch, and two notches are formed to face each other. 9b and 9c are rigid portions on both sides of the cutout 9a, and 9d is a thin portion formed by the two cutouts 9a. A denotes an axis passing through the center of the thickness of the thin portion 9d and parallel to the wall of the thin portion 9d, and B denotes an axis passing through the center of the thin portion 9d and orthogonal to the axis A. This translation pair 9 is a rigid body
One of the rigid parts 9b and 9c is fixed, for example, and the other rigid part is fixed.
When a force component in the direction orthogonal to the axes A and B is applied to 9c, deflection occurs around the axis A, and when a force component in the direction of the axis B is applied, the thin portion 9d expands and contracts slightly. But,
It has high rigidity against other force components and moment components.

A comparison between the rotating pair 3 shown in FIG. 7 and the translation pair 9 shown in FIG. 8 shows that the configurations of the cutout portions 3a and 9d are different.
And it is clear that the former can be formed much easier than the latter. Further, the rotating pair 3 also has the following advantages as compared with the translation pair 9. That is, each of these couples is deformed by the action of a force component, and by repeating this deformation, minute dust is generated from the deformed portion. Such dust poses a serious problem in, for example, semiconductor manufacturing equipment. For this reason, it is usual to provide a cover on the dust generating portion. Here, when providing a cover to the rotation pair 3 and the translation pair 9, the former thin portion 3d is shorter in length than the latter thin portion 9d, and
Since the deformation is also small, the cover is easier to install in the rotating pair 3 than in the translation pair 9.

[Problems to be solved by the invention]

Since a rotating pair has the above advantages as compared with a translation pair, it is desirable to use a rotating pair as shown in FIG. 6 when configuring a fine movement mechanism. However, since the rotation pair naturally performs a rotational displacement, when this is used for the translational displacement, it adversely affects the translational displacement. That is, in the fine movement mechanism shown in FIG. 6, when the actuator 5 is excited to displace the upper rigid body 2, it is inevitable to include a small but z-axis displacement together with the x-axis displacement. . As a result, an error occurs in the positioning, and there is a limit in the positioning accuracy. Therefore, there is a problem that the rotating couple cannot be used for the fine movement mechanism of the device that requires high-precision translational displacement.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a fine movement mechanism that can be constituted only by a rotating pair.

[Means for solving the problem]

In order to achieve the above object, the present invention uses a pair structure, and in a fine movement mechanism that generates a translational displacement in a predetermined direction by deforming the pair structure by an actuator, at least a frame formed in a substantially mouth shape. A connecting portion that is disposed in this frame and is formed in a substantially cross shape, and is disposed in each space formed by the frame and the connecting portion, and between the frame and the connecting portion of these spaces, respectively. A connected L-shaped connection chain, and an actuator mounted between the frame and the end of the connection portion for displacing the connection portion in a first direction and a second direction substantially perpendicular to each other. And is not displaced in directions other than the first direction and the second direction and in the rotation direction.

The fine movement mechanism according to claim 1, wherein
Direction and the direction of rotation about two axes parallel to the second direction, respectively, and 3
A second block displaceable in three dimensional directions is connected to the block.

[Action]

When the actuator is energized, the connecting chains of each block will attempt to deform accordingly. This deformation movement is allowed only for a movement that causes a translational displacement in a direction common to all connection chains, and a deformation movement that causes a translational displacement in a direction that is not common is suppressed by the connection chain of other blocks and does not occur. As a result, it is possible to obtain only translational displacement in a common direction selected in advance.

〔Example〕

 Hereinafter, the present invention will be described with reference to the illustrated embodiments.

FIG. 1 is an exploded perspective view of a fine movement mechanism according to a first embodiment of the present invention. In the figure, x, y, and z indicate coordinate axes. Reference numeral 10 denotes a first block, and reference numeral 11 denotes a second block, both of which are constituted by rigid members. The block 10 includes a base 101, a connecting portion 102, and a screw hole 103 provided in the connecting portion 102, and a plurality of rotating pairs 3 are formed by electric discharge machining or the like. Three rotating pairs 3 are formed on both sides, and these three rotating pairs form a connection chain. All of the rotating pairs formed in the block 10 have a rotation axis in the x-axis direction. 104 is a strain gauge attached to one thin portion of the rotating pair.

The block 11 includes a rectangular frame 111, a central connecting portion 112, and a screw hole 113 provided in the connecting portion 112. Reference numerals 114a to 114d denote connected chains composed of three rotating pairs, and each connected chain 114a to 114d is a frame.
It is mounted between 111 and the connecting portion 112. The rotating pairs forming the connecting chains 114a to 114d all have a rotating axis in the z-axis direction. Reference numeral 115 denotes an actuator mounted between the frame 111 and the connecting portion 112. Blocks 10 and 11 are connected using screw holes 103 and 113 as indicated by dashed arrows.

Before explaining the operation of the fine movement mechanism, first,
The operations of 10 and 11 will be described with reference to the drawings. Fig. 2 (a)-
(D) is an explanatory diagram of the operation of the block 10. In the figure, x,
y and z indicate the same coordinate axes as those shown in FIG.
Parts equivalent to those in FIG. 1 are denoted by the same reference numerals. In the figure, the rotating pair 3 is represented by a straight line and a small circle, and the straight line indicates a rigid body portion, and the small circle indicates a thinly rotating thin portion. Fig. 2 (a)
Is a view showing a non-deformed state, which shows that two connection chains composed of three rotating pairs are formed between the base 101 and the connection portion 102. FIG. 2 (b) to 2 (d) are views showing a deformed state, in which broken lines show the same non-deformed state as in FIG. 2 (a). The base 101 is fixed as shown.

When a moment about the x-axis is applied to the block 10 from the undeformed state shown in FIG.
The connecting portion 102 is deformed as shown by a solid line in FIG. In the case shown,
The deformations are exaggerated for ease of understanding (the same applies to the following figures). Further, when the non-deformed state exerting a z-axis direction of the force on the block 10, the connecting linkage is deformed as shown by the solid line in FIG. 2 (c), to translational displacement in the z-axis direction by a distance d _1. Further, when a force in the y-axis direction is applied to the block 10 from the non-deformed state, each connection chain becomes the second
FIG deformed as shown by the solid line (d), the distance d ₂ in the y-axis direction
Only translational displacement. On the other hand, unlike these displacements, the block 10 cannot perform rotational displacement about the y-axis and z-axis and translational displacement in the x-axis direction.

3 (a) to 3 (d) are diagrams for explaining the operation of the block 11. In the figure, x, y, and z indicate the same coordinate axes as those shown in FIG. 1, and portions equivalent to those in FIG. 1 are denoted by the same reference numerals. 3 (a) to 3 (d), each rotating pair is shown in the same manner as FIGS. 2 (a) to 2 (d). FIG. 3A shows a non-deformed state. FIG. 3 (b)
(D) is a diagram showing a deformed state, in which FIG.
The broken line shows the same undeformed state as in FIG. 3 (a). In this case, it is assumed that the connecting portion 112 is in a fixed state.

When a moment about the z-axis is applied to the frame 111 of the block 11 from the non-deformed state shown in FIG.
Each of the connecting chains 114a to 114d is deformed as shown by a solid line in FIG. 3 (b), and the frame 111 is rotationally displaced around the z axis by an angle Θ. Further, from the non-deformed state, the frame 111 when the action of the y-axis direction force, the connecting linkage is deformed as shown by the solid line in FIG. 3 (c), the frame 111 by a distance d ₁ in the y-axis direction Translates. Further, when a force in the x-axis direction is applied to the frame 111 from the non-deformed state, each connecting chain is deformed as shown by a solid line in FIG.
Is translational displacement in the x-axis direction by a distance d _2. On the other hand, unlike these displacements, the block 11 cannot perform rotational displacement about the x-axis and y-axis and translational displacement in the z-axis direction.

Next, the operation of the fine movement mechanism of this embodiment shown in FIG. 1 will be described. 2 (a)-(d) and 3 (a)-
From the description of (d), the connection chain of the block 10 can only perform rotational displacement about the x-axis, translational displacement in the z-axis direction, and translational displacement in the y-axis direction. It can be seen that only rotational displacement around, translational displacement in the y-axis direction, and translational displacement in the x-axis direction are possible.

The above can be expressed by the following equation when expressed by the kinematic equation of the connection chain.

S ₁₀ = [x, εy, εz] (1) S ₁₁ = [εx, εy, z] (2) where S ₁₀ is the motion equation of the block 10, and S ₁₁ is the motion equation of the block 11 , Εx, εy, εz represent translational displacements in the x, y, and z-axis directions, respectively, and x, z represent rotational displacements about the x, z-axes, respectively.

Since the fine movement mechanism of the present embodiment has a configuration in which the block 10 and the block 11 are connected, the kinematic expression is as described in the above (1),
The expression (2) is synthesized. Therefore, since the motion components x and εz in the equation (1) are not included in the equation (2), these motion components are restricted by the connection chain of the block 11, and similarly, the motion components εx and z in the equation (2). Are not included in the equation (1), the motion components are constrained by the connection chain of the block 10. As a result, the motion component which is not restricted at all is the motion component εy common to the equations (1) and (2).
Only.

As a result, the fine movement mechanism of the present embodiment has a motion component εy,
That is, only translational displacement in the y-axis direction is possible, and the base 101
When the actuator 115 is expanded and contracted in a state where is fixed, the frame 111 is translated and displaced in the y-axis direction according to the expansion and contraction.

Note that the strain gauge 104 is used for detecting the magnitude of the translational displacement, and the translational displacement is controlled based on the detected value.

As described above, in the present embodiment, a connection chain composed of only a rotating pair is provided in each of the two coupled blocks, and one common translational displacement among the displacements of the connection chain of each block is made to exist. Therefore, displacements other than the common translation displacement are mutually restricted by each block, and high-precision translation displacement can be performed despite the use of a rotating pair. In addition, the above-mentioned advantage of using only the rotating pair can be ensured, that is, easy production and effective prevention of dust can be ensured. Also,
Since there is no need to consider the rotation component, control of the fine movement mechanism can be easily and significantly simplified.

The fine movement mechanism shown in FIG. 1 is a mechanism that performs a translational displacement in a uniaxial direction (y-axis direction), but a fine movement that performs a translational displacement in a biaxial direction or a triaxial direction by selecting and combining predetermined blocks. A mechanism can be configured. Hereinafter, these fine movement mechanisms will be described with reference to the drawings.

FIG. 4 is an exploded perspective view of a fine movement mechanism according to a second embodiment of the present invention. In the figure, reference numeral 11 is a block equivalent to the block 11 shown in FIG. This block 11 is different from the block 11 shown in FIG. 1 in that the connecting portion 112 of this embodiment has a cross shape and the actuator 116 is provided at a position where the angle of the actuator 116 is different from that of the actuator 115 by 90 degrees. is there. In this embodiment, instead of the block 10 shown in FIG.
The illustrated block 12 is used. The block 12 includes a connecting chain 12a composed of three rotating pairs and two connecting chains 12b. The rotating pairs of the connecting chains 12a all have a rotating axis in the x-axis direction, and the rotating pairs of the connecting chain 12b all have a rotating axis in the y-axis direction.

Further, the block 12 includes a base 121 and a first connecting portion 12.
2. A strain gauge 123 attached to a thin portion of one rotating pair of the connecting chain 12a, and a second connected to the first connecting portion 122.
Connecting portion 124, third connecting portion 125, screw hole 126, and
It has a strain gauge 127 attached to a thin portion of one rotating pair of the connecting chain 12b. The third connecting portion 125 is connected to the connecting portion 112 of the block 11 by screw holes 113 and 126.

In this embodiment as well, the operation will be described using the kinematic expression of the connection chain, as in the previous embodiment. S ₁₁ motion equation of block 11, ligation chain 12a, S ₁₂ 12b equations of motion, respectively
a, S ₁₂ b, and the displacement of each axis is expressed using the same sign as the previous equation of motion. S ₁₁ = [εx, εy, z] (3) S ₁₂ a = [x, εy, εz] (4) S ₁₂ b = [εx, y, εz] (5)

Here, the motion equation of the block 12 and S _12, S ₁₂ is expressed by the following equation.

S ₁₂ = S ₁₂ a + S ₁₂ b = [x, εx, y, εy, εz] (6) Since the fine movement mechanism of the present embodiment has a configuration in which the block 11 and the block 12 are combined, Is the above (3),
Expression (6) is synthesized. Therefore, since the motion component z in the equation (3) is not included in the equation (6), this motion component is constrained by the connection chain of the block 12, and similarly,
Since the motion components x, y, and εz in the equation (6) are not included in the equation (3), the motion components are constrained by the connection chain of the block 11, and the motion components that are not constrained at all are ( Motion components εx, εy common to equations 3) and (6)
Only.

As a result, the fine movement mechanism of the present embodiment has the motion component εx,
εy, that is, only translational displacement in two axes in the x- and y-axis directions is possible. When the actuator 115 is expanded and contracted while the base 121 is fixed, the frame 111 is translated and displaced in the y-axis direction in accordance with the expansion and contraction. When the frame 111 expands and contracts, the frame 111 is translated and displaced in the x-axis direction according to the expansion and contraction. The effect of this embodiment is the same as the effect of the previous embodiment except that biaxial translational displacement is possible.

FIG. 5 is an exploded perspective view of a fine movement mechanism according to a third embodiment of the present invention. In the figure, x, y, and z are the same coordinate axes as those shown in FIGS. 1 and 4, and 13, 14, and 15 are blocks each formed by a connection chain. 131 and 132 are connecting portions at both ends of the block 13, 141 and 142 are connecting portions at both ends of the block 14, and 151 and 152 are connecting portions at both ends of the block 15. The block 13 is composed of connecting chains 13a and 13b. This configuration is the same as the configuration of the block 12 shown in FIG.
Each of the blocks 14 and 15 is composed of the same connection chain as the connection chains 13a and 13b, but the direction of each connection chain is different.

Here, the motion equations of blocks 13, 14, and 15 are respectively
Assuming that S ₁₃ , S ₁₄ , and S ₁₅ , S ₁₃ = [x, y, εx, εy, εz] (7) S ₁₄ = [x, z, εx, εy, εz] (8) S ₁₅ = [y, z, εx, εy, εz] (9)

Therefore, the fine movement mechanism of the present embodiment is (7)
The common displacements εx, εy, εz in equations (8) and (9), that is,
Translational displacements in three x, y, and z axes are possible. This three-axis translational displacement is achieved, for example, by fixing the connecting portion 131 of the block 13 to the fixed portion, and expanding and contracting in the x, y, and z-axis directions between the appropriate portion of the connecting portion 152 of the block 15 and the fixed portion. It is obtained by mounting and disposing an actuator to be mounted. When positioning an object, the table on which the object is placed
It will be fixed at 152. The effect of this embodiment is the same as that of each embodiment except that a three-axis translational displacement is possible.

The actuator in each of the above embodiments is mounted with its both ends in contact with a rigid body. If this mounting is performed via a rotating pair, a smoother operation can be expected.

〔The invention's effect〕

As described above, in the present invention, since the fine movement mechanism is configured by connecting a plurality of blocks formed of a connection chain consisting of only a rotating pair, it is easy to manufacture, and while maintaining the advantage of the rotating pair that dust prevention is easy, High-precision fine movement without errors can be performed. Further, since there is no need to consider the rotation component, the control device of the fine movement mechanism can be simply configured.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a fine movement mechanism according to a first embodiment of the present invention, and FIGS. 2 (a) to (d) and FIGS. 3 (a) to 3 (a).
(D) is an operation explanatory view for explaining the operation of the fine movement mechanism shown in FIG. 1, and FIGS. 4 and 5 are exploded perspective views of the fine movement mechanism according to the second and third embodiments of the present invention, respectively. FIG. 6 is a side view of a conventional fine movement mechanism, and FIGS. 7 and 8 are perspective views of a rotation pair and a translation pair, respectively. 3 ... rotating pair, 10, 11, 12, 13, 14, 15 ... block, 114a to 114c ... connecting chain, 115, 116 ... actuator

Claims (2)

(57) [Claims] 1. A fine movement mechanism using a pair structure and deforming the pair structure by an actuator to generate a translational displacement in a predetermined direction, comprising: a frame formed at least in a substantially mouth shape; A connection part formed in a substantially cross shape, a substantially L-shaped connection part disposed in each space formed by the frame and the connection part, and connected between the frame and the connection part in these space parts, respectively. A block comprising: a connection chain; and an actuator mounted between the frame and the end of the connection portion, the actuator being configured to displace the connection portion in a first direction and a second direction substantially perpendicular to each other. A fine movement mechanism that does not displace in a direction other than the first direction and the second direction and in a rotation direction. 2. The displacement according to claim 1, wherein said first direction and said second direction are respectively rotated around two axes parallel to said first direction and said second direction, and three-dimensional directions are parallel to said respective axes. A fine movement mechanism, wherein a possible second block is connected to said block.