JPS63281111A - Mirror supporting device - Google Patents

Abstract

PURPOSE:To prevent the generation of a concentrated stress for deteriorating the profile irregularity of a mirror, by constituting the titled device so that the displacement in the X, P and (y) directions of the mirror is detained in an overhung state by a rod-like member having flexibility. CONSTITUTION:By three pieces of thin rod-like members 12 having flexibility attached to the reverse side of a mirror 11, and a fixing means 13 for fixing the rod-like member 12, the displacement in the directions of X (the axial direction of the mirror 11), P (the rotating direction whose rotation center is a straight line in the horizontal direction being vertical to the axis of the mirror 11), and (y) (the rotating direction whose rotation center is a vertical line) of the mirror is detained so that it can be adjusted. Also, by receiving bases 17, 19, the mirror 11 is supported so that it can be displaced in the X, P and (y) directions. Even in case a swing and tilt adjustment of the mirror 11, namely, a P and (y) adjustment has been executed, the receiving bases 17, 19 being movable in the X, P and (y) directions follow moderately a mirror position determined by three pieces of rod-like members 12. In such a way, a concentrated stress for deteriorating the profile irregularity of the mirror 11 is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a support device for a large mirror used in a projection exposure apparatus.

2. Description of the Related Art Conventional large mirror support devices include, for example, Japanese Patent Laid-Open No. 81-7
There is a conventional example as disclosed in Japanese Patent No. 4335.

This will be explained below based on the drawings.

In Figures 3 and 4, 1 is a mirror, 2 is a mini 7-1
3 is a plurality of rods that determine the position of the flange portion of the mirror 1, and 4 is a spring that faces the rod 3 and presses the flange portion of the mirror 1 toward the rod 3 side with a constant pressure.

In the above configuration, the mirror 1 is supported by its weight by the V-shaped block 2, so that the mirror 1 can move in the Z direction and Y direction in the figure.
The displacement in the direction is restrained by the rod 3 and the spring 4,
The displacement in the X direction, the P direction, and the X direction is restrained, and the displacement in the Y direction is restrained by the frictional force between the V-shaped block 2 and the mirror 1 and the supporting force of the rod 3.

Problems to be Solved by the Invention However, in the conventional example, concentrated stress is generated on the mirror 1 due to the mirror 1 being compressed by the rod 3 and the spring 4, and distortion is generated that reduces the surface accuracy of the mirror. do.

Furthermore, if the end faces of each rod 3 are not on the same plane, a bending moment is generated in the mirror 1, causing distortion. Furthermore, when trying to adjust the tilt of the mirror 1, that is, the P direction and the have.

SUMMARY OF THE INVENTION In view of the drawbacks of the conventional example, it is an object of the present invention to provide a mirror support device with less concentrated stress that reduces the surface accuracy of the mirror.

Means for Solving the Problems A device for vertically supporting a circular mirror, comprising three thin flexible rod-like members attached approximately perpendicularly to the back surface of the mirror, and one for each of the rod-like members. A fixing means that adjustably fixes the axial position, and a total of three degrees of freedom: rotation about the axial direction of the mirror, rotation about a vertical line, and rotation about a horizontal straight line perpendicular to the axis of the mirror. The present invention is characterized in that it comprises a pedestal for the mirror, which is freely provided, a fixing means for the rod-shaped member, and a base for supporting the pedestal for the mirror.

Function The present invention provides a flexible mirror attached to the back surface of the mirror.
As shown in FIG. 1 or 2, the thin rod-like member of the book and the fixing means for fixing the rod-like member are used to align the X (axis direction of the mirror) and P (horizontal straight line perpendicular to the axis of the mirror) of the mirror. (rotational direction with the vertical line as the center of rotation), and y (rotational direction with the vertical line as the center of rotation) so as to be adjustable, and support the mirror so that it can be displaced in the z, p, and x directions using a pedestal. Can be done.

As a result, a large bending moment is not generated in the mirror when the mirror is pinched as in the conventional example, and even when the mirror is tilted, that is, the P and y adjustments are made, the x, p, The cradle, which can be freely moved in any direction, easily follows the mirror position determined by the three rod-shaped members, and has the excellent feature of not producing concentrated stress that degrades the surface accuracy of the mirror.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIGS. 1 and 2, 11 is a mirror, 12 is a flexible thin rod-shaped member fixed to the back surface of the mirror 11,
13 is a fixing means with a screw mechanism that determines the position of the bar member 12 in the X direction, and 14 is a pad attached to the lower surface of the outer periphery of the mirror 11.

Reference numeral 17 denotes an X table that supports the mee 7-11 through a steel ball 16 and a conical hole 16 so as to be movable in the P direction. 19 is a yawing table, and the X table 17 is connected to the linear guide 1.
The base 2 is displaceably supported in the X direction via the base 2.
1 via a rotary bearing 2o so as to be displaceable in the X direction. These X table 17, yawing table 1
9 constitutes a cradle of the present invention.

In the above configuration, the mirror 11 is fixed by the three thin rod-shaped members 12 and the fixing means 13 with a screw mechanism.
cradle 17.
19 so as to be movable in the x, p, and x directions.

Note that the displacement of the mirror 11 in the Z, Y, and r directions is determined by the pedestal 17.
19.

In this way, the displacement of the mirror 11 in the x, p, and without causing
Therefore, concentrated stress that degrades surface accuracy is not generated.

Furthermore, even if the thin rod-shaped member 12 and the fixing means with screw mechanism 13 are used to perform the tilt adjustment, that is, the P and Y adjustment, the lower pedestal will easily follow this adjustment, so that the tilt adjustment can be adjusted as in the conventional example. No concentrated stress is generated during adjustment.

In this embodiment, the degree of freedom in the P direction of the lower pedestal is realized by the steel ball 16 and the conical hole 16), but this is achieved by, for example, integrating the pad 14 and using a normal rotation bearing. It may also be fixed to the X-table 17 using the X-table. Also, increase the degree of freedom of the lower pedestal.

Although X and y are used, this is not limited to this order.
In short, the lower pedestal only needs to have three degrees of freedom: p, x, and y.

Effects of the Invention As described above, according to the present invention, the displacement of the mirror in the x, p, and y directions is restrained by the relatively soft bending rigidity of the rod-shaped member, and the pedestal is movable in the x, p, and y directions. Because the structure is such that the mirror is restrained in the Z and Y directions without strain, and the Y direction is restrained by the frictional force generated between the mirror and the pedestal due to the weight of the mirror, the restraint forces may interfere with each other. Therefore, concentrated stress that degrades the surface accuracy of the mirror does not occur. Moreover, even when performing the tilt adjustment, that is, the P and y adjustment, no excessive force is applied, which has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of a mirror support device according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the same, Fig. 3 is a front view of a conventional mirror support device, and Fig. 4 is a longitudinal sectional view of the same. It is a front view. 11...mirror, 12...rod-shaped member,
13...Fixing means with screw mechanism, 17...
...X table, 19...Yawing table, 21...Base. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure Mi

Claims (1)

[Claims] A device for vertically supporting a circular mirror, comprising three thin flexible rod-shaped members attached approximately perpendicularly to the back surface of the mirror, and each of the rod-shaped members fixed in an adjustable axial position. and a fixing means for fixing the mirror, and a mirror having a total of three degrees of freedom, including rotation about the axial direction of the mirror, rotation about a vertical line, and rotation about a horizontal straight line perpendicular to the axis of the mirror. A mirror support device comprising a pedestal, means for fixing the rod-shaped member, and a base for supporting the pedestal of the mirror.