JP2000214280A - Stage mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make absorbable the change in part dimensions in a stage mechanism due to a shape error in machining and thermal expansion. SOLUTION: On a base 1, rails 2 and 3 extending in a predetermined direction are arranged with a specific interval. Moving bodies 4 and 5 are arranged on the rails 2 and 3 and the moving bodies 4 and 5 move along the rails 2 and 3, respectively. The moving bodies 4 and 5 are connected with a beam 6 and the beam extends to a direction perpendicular to a predetermined direction. One end of the beam is fixed to the moving body 4 and the other end of the beam is fixed to the moving body 5 by way of a plate spring 8 extending in the predetermined direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage mechanism which moves in the rail direction using two fixed rails as guides, and more particularly to a structure of a leaf spring used in the stage mechanism.

[0002]

2. Description of the Related Art In general, a stage mechanism which moves in the rail direction using two rails as guides is known.

Here, a conventional stage mechanism will be described with reference to FIG.

[0004] On a base 1, two rails 2 and 3 are arranged at a predetermined interval. Moving bodies 4 and 5 are arranged on the rails 2 and 3, respectively, and the moving bodies 4 and 5 move (move) on the rails 2 and 3, respectively. The moving bodies 4 and 5 are connected by a beam 6. As a result, the moving bodies 4 and 5 move to the rails 2 and 3
The beam 6 will move as it moves up.

In the stage mechanism shown in FIG. 4, in order to move the beam 6 smoothly in the rail direction, the rail 2
It is necessary to strictly control the distance (inter-rail distance) and the beam length (length in the inter-rail distance direction) between the first and the third and the third. In addition, in order to cope with a dimensional change due to thermal expansion conversion caused by a change in environmental temperature, mechanical parts constituting the stage mechanism are made of the same type of material or a material having a similar thermal expansion coefficient.

On the other hand, for example, as shown in FIG. 5, a stage mechanism using a static pressure air bearing for linear motion guide is known.

Referring to FIG. 5, in FIG. 5, the same components as those in FIG. 4 are denoted by the same reference numerals. In the illustrated example, the moving body 4 is several μm to ten and several μs with respect to the rail 2.
m, and compressed air is supplied to this gap. Thus, the moving body 4 moves while floating with respect to the rail 2 with a predetermined gap. That is, a static pressure air bearing function is provided between the moving body 4 and the rail 2.

[0008]

By the way, in recent years, the size of the stage mechanism has been increasing, and in the case of the stage mechanism shown in FIG. 4, if the distance between the moving bodies 4 and 5 increases, the plate mechanism is inevitably increased. As the length increases, the difference in thermal expansion cannot be ignored when the environmental temperature changes, even if the material of the mechanical parts is the same type.As a result, it is difficult to move the plate smoothly in the rail direction. There is a problem that.

On the other hand, also in the stage mechanism shown in FIG. 5, when the distance between the rails and the plate length change due to the difference in thermal expansion, the gap between the moving body 4 and the rail 2 changes. This change in the gap results in a change in the air film thickness, which adversely affects the guide performance. In addition, when the beam 6 is cantilevered by using only the moving body 4 without using the moving body 5, the gap between the moving body 4 and the rail 2 is greatly changed, which greatly affects the guide performance. Give it.

Further, in the stage mechanism shown in FIG. 5, it is impossible to reduce the parallelism or straightness of the two rails 2 and 3 to zero. ) Occurs, and a force for bending the beam 6 is generated. This force acts as a force that changes the air film thickness, and this also has a problem that the guide performance is adversely affected and the static pressure air bearing is damaged.

As described above, in the conventional stage mechanism, when a mechanical component thermally expands due to a change in environmental temperature, if the stage mechanism uses a static pressure air bearing, a gap between the static pressure air bearing and the fixed guide is provided. As the amount changes, the stiffness value of the bearing changes. In addition, if there is a remarkable temperature change, the gap amount becomes negative, which may cause deformation or damage of the mechanical structure.

An object of the present invention is to provide a stage mechanism capable of absorbing a shape error due to machining and a change in component size due to thermal expansion.

[0013]

According to the present invention, first and second rails are provided on a base at predetermined intervals and extend in a predetermined direction, and the first and second rails are provided.
The first and second rails are respectively used as guides.
First and second moving bodies that move along the rails, and beams connected to the first and second moving bodies, wherein the beams are arranged in a direction orthogonal to the predetermined direction. Extending, one end of the beam is fixed to the first moving body, and the other end of the beam is fixed to the second moving body via a leaf spring extending in the predetermined direction. A characteristic stage mechanism is obtained.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

First, referring to FIG. 1, in FIG. 1, the same components as those in FIG. 5 are denoted by the same reference numerals.
Two rails 2 and 3 are arranged on the base 1 at a predetermined interval, and moving bodies 4 and 5 are arranged on the rails 2 and 3, respectively. Here, paying attention to the rail 2 and the moving body 4, as shown in FIG. 1B, the moving body 4 is provided with a static pressure air bearing pad 12, and between the rail 2 and the moving body 4. Is the static pressure air bearing pad 12
Is interposed. The moving body 4 is guided by the static pressure air bearing pad 12 in the X-axis direction shown in FIG. Further, as shown in FIG. 1 (b), the moving body 4 is provided with a static pressure air bearing pad 13.
1 is a static pressure air bearing pad, which is guided by the base 1 in the Z-axis direction (upward in FIG.
It moves along the Y-axis direction shown in FIG.

Similarly, the moving body 5 is also provided with static pressure air bearing pads 12 and 13, and the moving body 5 is movable along the rail 3.

The beam 6 is rigidly connected to the moving body 4 (for example,
The beam 6 is connected to the moving body 5 by a leaf spring structure described later.

Here, referring also to FIG. 2, an L-shaped angle 7 is attached to one end of the beam 6 by a screw or the like. Similarly, the L-shaped angle 9 is also attached to the moving body 5. It is attached with screws. These angles 7 and 9 are opposed to each other in the Y-axis direction in FIG. A thin rectangular leaf spring 8 is arranged between the angles 7 and 9. That is, one end of the leaf spring 8 is fixed to the angle 7 via the contact plate 7a by a bolt, and the other end of the leaf spring 8 is fixed to the angle 9 by the bolt via the contact plate 9a. As a result, the leaf spring 8 extends in the Y-axis direction.

When the moving bodies 4 and 5 move in the Y-axis direction, a compressive and tensile force is applied to the leaf spring 8 in the longitudinal direction, that is, in the Y-axis direction, so that the beam 6 and the moving body 5 have high rigidity. Move as if they were rigidly connected.

Here, when the environmental temperature changes and, for example, the length of the beam 6 (beam length) becomes relatively longer than that of the base 1 due to thermal expansion, the dimensional change is changed by the leaf spring 8.
Will be absorbed by the bending. That is, when the beam length is increased by thermal expansion (increased in the X-axis direction), the leaf spring 8 extends in the Y-axis direction in FIG. As a result, the dimensional change of the beam 6 is absorbed.

As described above, since the direction in which the force is generated due to the change in the beam length is the bending direction of the leaf spring, the force generated in the moving body 5 in the X-axis direction affects the air film thickness of the static pressure air bearing. Can be reduced according to the design to a level that does not give.

Referring to FIG. 3, in the example shown in FIG. 3, a moving body 14 is arranged on beam 6, and moving body 14 moves in the X-axis direction in FIG. I do. That is, FIG. 3 shows the XY stage mechanism. In FIG. 3, the same components as those in the example shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 3B, between the base 1 and the moving body 14, there are provided static pressure air bearing pads 14a to 14a.
c is arranged. That is, the static pressure air bearing pads 14a to 14c are attached to the moving body 14,
The moving body 14 is guided in the Z-axis direction with respect to the base 1 by the static pressure air bearing pads 14a to 14c, and moves in the X-axis direction.

Also in the illustrated XY stage mechanism, as described with reference to FIG. 1, since the beam 6 and the moving body 5 are connected by the leaf spring 8, the length of the beam 6 (beam length) Is larger than that of the base 1 due to thermal expansion, the dimensional change is absorbed by the bending of the leaf spring 8.

[0025]

As described above, in the present invention, since the beam and the moving body are connected by the leaf spring, the dimensional change of the beam can be absorbed by the bending of the leaf spring, and as a result, the load on the guide can be reduced. Can be reduced. That is, not only the assembling work is facilitated, but also the guide performance is improved, and the guide accuracy of the moving body can be maintained even if the processing accuracy and the assembling accuracy of the parts alone are not high.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a stage mechanism according to the present invention, wherein (a) is a plan view and (b) is a sectional view.

FIG. 2 is a view showing a leaf spring structure used in the stage mechanism shown in FIG. 1;

3A and 3B are diagrams showing another example of the stage mechanism according to the present invention, wherein FIG. 3A is a plan view and FIG. 3B is a cross-sectional view.

FIG. 4 is a diagram showing an example of a conventional stage mechanism.

FIG. 5 is a diagram showing another example of a conventional stage mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2,3 Rail 4,5,14 Moving body 6 Beam 7,9 Angle 8 Leaf spring 12,13 Static pressure air bearing pad

Claims (1)

[Claims] 1. first and second rails arranged on a base at a predetermined interval and extending in a predetermined direction;
First and second moving bodies that move along the first and second rails, respectively, using the first and second rails as guides, and are connected to the first and second moving bodies. A beam extending in a direction orthogonal to the predetermined direction, one end of the beam is fixed to the first moving body, and the other end of the beam is connected to the second moving body. A stage mechanism fixed via a leaf spring extending in the predetermined direction.