JP2013186081A - Movement table device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movement tabl device that hardly causes deformation of a movement table, and can move the movement table in a stable posture even when accuracy of a bearing guide surface of a static pressure gas bearing is insufficient.SOLUTION: A rotary table device comprises: a base 2 that is provided with an air pad 6; and a rotary table 1 that is rotatably supported on the base 2 by a rotary guide mechanism 4. The air pad 6 is provided with a bearing part 10 that includes a gas bearing surface 10a having an exhaust nozzle 10b for exhausting gas formed and a housing part 11 that holds the bearing part 10 movably/retractably in a vertical direction of the gas bearing surface 10a, and is capable of configuring a static gas bearing between a bearing guide surface 1a formed on a bottom surface of the rotary table 1 and the gas bearing surface 10a. The air pad 6 is provided with an air spring that moves and retracts the bearing part 10 in the vertical direction of the gas bearing surface 10a and keeps a vertical distance between the rotary table 1 and the base 2 constant.

Description

  The present invention relates to a moving table device.

  An example of a conventional linear motion table device is shown in FIG. This linear motion table device includes a moving table 101, a table base 102, a ball screw 103, and four linear guides 104. The ball screw 103 and the linear guide 104 are provided between the moving table 101 and the table base 102, but the ball screw 103 is arranged at the center in the table width direction (direction perpendicular to the linear motion direction). The linear guides 104 are disposed at both ends in the table width direction and between the linear guides 104 and the ball screws 103 at both ends. On the moving table 101, a fixed body or a moving body 105 (for example, a moving table having a moving direction different from that of the moving table 101) is placed.

  In such a linear motion table device, since the moving table 101 is supported by the four linear guides 104, it is not easily deformed by its own weight or the load of the load, and the moving table 101 is moved along with the movement of the moving body 105. It is hard to be deformed by movement of the center of gravity. Accordingly, since the core height of the ball screw 103 hardly changes due to the deformation of the moving table 101, the moving table 101 can be moved in a stable posture. However, since it is necessary to accurately adjust the height and moving direction of the four linear guides 104, there is a problem that it is very difficult to adjust the linear motion table device during assembly.

  Therefore, a linear motion table device in which such a problem is unlikely to occur is proposed in Patent Document 1 (see FIG. 7). The linear motion table device disclosed in Patent Document 1 is the same as the linear motion table device in FIG. 6, instead of providing two linear guides 104 between the linear guides 104 and the ball screws 103 at both ends in the table width direction. The moving table 101 is provided with an air pad 106 that blows air toward the table base 102 from the 101 side.

  By adjusting the air blowing pressure of the air pad 106 according to the weight of the moving table 101 and the mass of the load, the center part in the table width direction of the moving table 101 is lifted upward, and the moving table 101 and the table base 102 are The interval (vertical distance) can be constant over the entire surface of the moving table 101. Thereby, even if the position of the center of gravity moves due to the movement of the moving body 105 loaded on the moving table 101, the moving table 101 is hardly deformed. Further, since the number of linear guides 104 is two, there is almost no problem that adjustment during assembly is very difficult unlike the linear motion table device of FIG.

JP-A-11-277351

However, since the air pad 106 is fixed to the moving table 101, if the accuracy of the plane of the table base 102, which is the bearing guide surface of the static pressure gas bearing, is poor, the distance between the air pad 106 and the bearing guide surface (vertical direction) The distance) is not constant, and varies depending on the location of the bearing guide surface.
For this reason, the force that lifts the moving table 101 from the table base 102 (that is, the force applied to the moving table 101 by the static pressure gas bearing) fluctuates, so the distance between the moving table 101 and the table base 102 (vertical direction). The distance) cannot be made constant over the entire surface of the moving table 101, and the moving table 101 may be deformed. As a result, the core height of the ball screw 103 is changed, and there is a possibility that the moving table 101 cannot be moved in a stable posture.
Accordingly, the present invention solves the problems of the prior art as described above, and even if the accuracy of the bearing guide surface of the static pressure gas bearing is insufficient, the movable table is hardly deformed and the movable table is in a stable posture. It is an object of the present invention to provide a moving table device that can be moved at a high speed.

  In order to solve the above problems, an aspect of the present invention has the following configuration. That is, the moving table device according to an aspect of the present invention includes a base, a moving table that linearly moves or rotates on the base, and the moving table that is arranged between the base and the moving table on the base. And a guide mechanism for guiding linear movement or rotation of the moving table while supporting, wherein a bearing guide surface of the static pressure gas bearing is provided on a surface facing the base of the moving table. A gas bearing surface formed with a jet port for ejecting gas, and ejecting gas from the gas bearing surface toward the bearing guide surface facing each other through a bearing gap, thereby the bearing guide surface and the gas bearing An air pad capable of forming a static pressure gas bearing is fixed to a surface of the base facing the moving table with the gas bearing surface facing the bearing guide surface. The air pad includes a bearing portion including the gas bearing surface, and a housing portion that is fixed to the base and holds the bearing portion, and the housing portion is configured such that the gas bearing surface is exposed. The bearing portion is held in the recess so as to be able to advance and retract in a direction perpendicular to the gas bearing surface, and the air pad further advances and retracts the bearing portion in a direction perpendicular to the gas bearing surface. And an advancing / retreating mechanism for maintaining a constant vertical distance between the moving table and the base.

  In such a moving table device, the advance / retreat mechanism is disposed between the housing part and the bearing part, and applies a biasing force in a direction perpendicular to the gas bearing surface to the housing part and the bearing part. It is preferable that More preferably, the spring is at least one of a coil spring and an air spring. Moreover, it is preferable that the advance / retreat mechanism includes an adjustment mechanism that adjusts an urging force of the spring.

  Since the moving table device of the present invention includes an air pad having an advance / retreat mechanism that keeps the vertical distance between the moving table and the base constant, the accuracy of the bearing guide surface of the static pressure gas bearing is insufficient. However, the moving table is hardly deformed, and the moving table can be moved in a stable posture.

It is sectional drawing which shows the structure of the turntable apparatus which is one Embodiment of the movement table apparatus which concerns on this invention. It is sectional drawing which shows the 1st modification of an air pad. It is sectional drawing which shows the 2nd modification of an air pad. It is sectional drawing which shows the 3rd modification of an air pad. It is sectional drawing explaining the example which applied the rotary table apparatus to the microscope. It is a front view which shows the structure of the conventional XY table apparatus. It is a front view which shows the structure of another conventional XY table apparatus.

Embodiments of a moving table device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing the structure of a rotary table device which is an embodiment of a moving table device according to the present invention.
A rotation guide mechanism 4 that guides the rotation of the rotary table 1 (corresponding to the moving table that is a constituent of the present invention) is installed on the upper surface of the flat base 2. The rotation guide mechanism 4 is arranged between a cylindrical housing 4a fixed to the upper surface of the base 2, a rotation shaft 4b inserted into the housing 4a, and the housing 4a and the rotation shaft 4b. On the other hand, a rolling bearing 4c that rotatably supports the rotating shaft 4b is provided. The housing 4 a is fixed to the base 2 so that the axial direction thereof is orthogonal to the upper surface of the base 2. Therefore, the rotation shaft 4 b rotates around the axis line in the direction orthogonal to the upper surface of the base 2. In place of the rolling bearing 4c, other types of bearings such as a hydrostatic bearing and a sliding bearing may be used.

  On the rotation guide mechanism 4, a disc-shaped rotary table 1 on which a load 5 such as a work can be placed is arranged and fixed so as to be parallel to the upper surface of the base 2. That is, the upper end portion of the rotation shaft 4 b is attached to the center portion of the turntable 1. The turntable 1 is supported on the base 2 by a rotation guide mechanism 4 and can be rotated around a rotation shaft 4b at a desired rotation speed by a rotation drive unit (not shown) such as a motor. It has become. The rotation driving unit may be of a type that transmits a rotation driving force to the rotation shaft 4b and rotates the rotation table 1 via the rotation shaft 4b, or directly transmits the rotation table 1 to the rotation table 1 by rotating the rotation table 1. It may be of a rotating type.

Further, an air pad 6 is attached to the upper surface of the base 2 facing the lower surface of the turntable 1. For example, the air pad 6 is disposed at a position facing the radially outer end of the turntable 1.
The number of installed air pads 6 may be one, but when the turntable 1 has a large diameter or a large mass, a plurality of air pads 6 are preferable. When a plurality of air pads 6 are installed, the plurality of air pads 6 may be installed side by side along the circumferential direction, or may be installed side by side along the radial direction. In the example of FIG. 1, the two air pads 6 are equally arranged in the circumferential direction while having a phase difference of 180 °.

  The air pad 6 includes a gas bearing surface 10 a in which a jet port 10 b for ejecting a gas such as air is formed, and this gas bearing surface 10 a is a bearing guide surface of a static pressure gas bearing formed on the lower surface of the rotary table 1. It is attached to the upper surface of the base 2 toward 1a. Therefore, the gas bearing surface 10a of the air pad 6 is opposed to the bearing guide surface 1a of the turntable 1 via a gap (bearing gap), and if gas is ejected from the gas bearing surface 10a toward the bearing guide surface 1a. A static pressure gas bearing (non-contact bearing) is configured between the bearing guide surface 1a and the gas bearing surface 10a.

  Here, the structure of the air pad 6 will be described in more detail with reference to FIG. The air pad 6 includes a substantially cylindrical bearing portion 10 and a housing portion 11 having a substantially cylindrical concave portion 11 a having a shape substantially corresponding to the outer diameter shape of the bearing portion 10. The housing portion 11 is fixed to the upper surface of the base 2 with the concave portion 11a facing the upper bearing guide surface 1a, and the bearing portion 10 is accommodated in the concave portion 11a of the housing portion 11.

  One of the two parallel planes of the substantially cylindrical bearing portion 10 faces the bottom surface of the recess 11 a of the housing portion 11. The other of the two parallel planes is exposed to the outside of the recess 11a and faces the bearing guide surface 1a, forming a gas bearing surface 10a that is a component of the hydrostatic gas bearing. The gas bearing surface 10 a is formed with a plurality of ejection ports 10 b that eject gas toward the bearing guide surface 1 a of the static pressure gas bearing formed on the turntable 1.

  The gas ejected from the ejection port 10b is introduced into the air pad 6 from an air supply port 13 opened on the outer surface of the housing part 11, and is formed in the air pad 6 (the housing part 11 and the bearing part 10). 14 is supplied to the spout 10b. That is, the air passage 14 of the housing portion 11 passes through the inside of the housing portion 11 to reach the bottom surface of the concave portion 11a and is connected to the air passage 14 of the bearing portion 10 that opens in a plane facing the bottom surface of the concave portion 11a of the housing portion 11. To do. In order to prevent gas leakage, a seal such as an O-ring 15 is attached to the connection portion between the air passages 14 and 14. The air passage 14 of the bearing portion 10 passes through the inside of the bearing portion 10 and is connected to a jet port 10b formed in the gas bearing surface 10a. The gas may be directly introduced into the bearing portion 10 without passing through the housing portion 11.

  Further, the air passage 14 of the bearing portion 10 branches inside the bearing portion 10 and opens to the cylindrical surface of the bearing portion 10. That is, a jet port 10c for jetting gas is also formed on the cylindrical surface of the bearing portion 10, and the gas is jetted to the cylindrical surface of the concave portion 11a of the housing portion 11 that faces the cylindrical surface of the bearing portion 10 through a gap. Thus, a static pressure gas bearing (non-contact bearing) is formed between both cylindrical surfaces. For the static pressure gas bearing between both cylindrical surfaces, the bearing clearance is set wide and the bearing rigidity is low so as not to disturb the advancement and retraction of the bearing portion 10 and to convey the influence of the inclination direction of the bearing guide surface 1a. Is preferred. However, if the bearing rigidity is too low, a resonance phenomenon may occur. Therefore, it is necessary to set the bearing rigidity to a level that does not cause the resonance phenomenon.

  Further, the housing portion 11 is provided with a through hole 16 (for example, a through hole extending in a direction parallel to the gas bearing surface 10a) that communicates the inner peripheral surface and the outer peripheral surface of the recess 11a. The gas ejected from the ejection port 10c formed on the cylindrical surface toward the cylindrical surface of the concave portion 11a of the housing portion 11 is an opening of the concave portion 11a facing upward (the cylindrical surface of the bearing portion 10 and the concave portion of the housing portion 11). 11a and the cylindrical surface of 11a) and the through hole 16 are also discharged to the outside of the air pad 6.

  Further, a bottomed hole 24 is formed at the center of the bottom surface of the recess 11a of the housing part 11, and an advance / retreat mechanism for advancing and retracting the bearing part 10 in the direction perpendicular to the gas bearing surface 10a in the bottomed hole 24. The spring which comprises is arrange | positioned. That is, the bearing portion 10 is held in the recess 11a of the housing portion 11 so as to be able to advance and retract in the direction perpendicular to the gas bearing surface 10a. In the example of FIG. 1, an air spring is provided as an advance / retreat mechanism, and this air spring applies a biasing force in the vertical direction of the gas bearing surface 10 a to the housing portion 11 and the bearing portion 10.

  More specifically, a bottomed hole 24 is formed at the center of the bottom surface of the recess 11 a of the housing portion 11. The space of the bottomed hole 24 is sealed with an O-ring 25 or the like so that gas can be supplied to the sealed space of the bottomed hole 24. If a gas is supplied to the space of the bottomed hole 24 to make a positive pressure, an air spring is formed, and the air spring constitutes the advance / retreat mechanism.

  The air spring applies a biasing force directed downward in the vertical direction of the gas bearing surface 10a to the housing portion 11, and applies a biasing force directed upward in the vertical direction of the gas bearing surface 10a to the bearing portion 10. By adjusting the pressure in the space of the bottomed hole 24, the strength of the urging force in the vertical direction of the gas bearing surface 10a applied to the housing part 11 and the bearing part 10 can be adjusted. What is necessary is just to adjust the pressure of the space of the bottomed hole 24 suitably according to the intensity | strength of the urging | biasing force (namely, force to give to the turntable 1) to apply to the.

  Next, the operation of the turntable device of this embodiment will be described. When the gas is introduced into the air pad 6 from the air supply port 13, the gas is ejected from the ejection port 10 b formed in the gas bearing surface 10 a of the bearing portion 10 toward the bearing guide surface 1 a of the turntable 1, and the bearing portion. A gas is ejected from the ejection port 10 c formed on the 10 cylindrical surface toward the cylindrical surface of the recess 11 a of the housing portion 11. As a result, a static pressure gas bearing is formed between the gas bearing surface 10a of the bearing portion 10 and the bearing guide surface 1a of the rotary table 1, and the cylindrical surface of the bearing portion 10 and the cylindrical surface of the recess 11a of the housing portion 11 are formed. A static pressure gas bearing is formed between the two.

Since a static pressure gas bearing is formed between both cylindrical surfaces, the bearing portion 10 and the housing portion 11 are maintained in a non-contact state on both cylindrical surfaces, and the bearing portion 10 can smoothly advance and retract. Further, since a static pressure gas bearing is configured between the gas bearing surface 10a of the bearing portion 10 and the bearing guide surface 1a of the rotary table 1, the bearing portion 10 has a force directed downward in the vertical direction of the gas bearing surface 10a. The gas bearing surface 10a of the bearing portion 10 and the bearing guide surface 1a of the rotary table 1 are maintained in a non-contact state.
As described above, the bearing portion 10 is given a biasing force that is directed upward in the vertical direction of the gas bearing surface 10a by the air spring (that is, a preload is given to the bearing portion 10 by the air spring). The bearing portion 10 is held in the recess 11 a of the housing portion 11 at a height position where the biasing force by the spring and the force by the static pressure gas bearing are balanced.

  Since the turntable 1 is supported by the rotation guide mechanism 4 at the center, and the radially outer end is not supported, the turntable 1 is deformed downward by receiving a load due to the weight of the turntable 1 or the mass of the load 5. There is a risk. Further, as shown in the figure, even when a downward pressing force acts on the load 5, the radially outer end of the rotary table 1 may be bent and deformed downward. However, since a force directed vertically upward acts on the radially outer end of the rotary table 1 by configuring the static pressure gas bearing, the radially outer end of the rotary table 1 is lifted upward.

  Therefore, the gas ejection pressure from the gas bearing surface 10a of the air pad 6 is set according to the weight of the turntable 1, the load due to the mass of the load 5, the pressing force against the load 5, etc. If the pressure in the space of the bottomed hole 24 is adjusted so as to apply an urging force, the radially outer end of the rotary table 1 is lifted upward, and the load due to the weight of the rotary table 1 and the mass of the load 5 The bending deformation due to the pressing force or the like on the load 5 is suppressed. As a result, the interval (vertical distance) between the rotary table 1 and the base 2 can be made constant over the entire rotary table 1.

  Therefore, when the deflection due to the weight of the turntable 1 is suppressed, a force directed upward in the vertical direction acts on the radial position (usually the radially outer end) that can most effectively suppress the deflection due to the weight. The air pad 6 is preferably disposed. Further, in the case of suppressing the load due to the mass of the load 5 and the bending due to the pressing force to the load 5, a force directed vertically upward acts on the radial position where the load 5 is placed. It is preferable to arrange the air pad 6. And when the some load 5 is mounted, it is preferable to install the air pad 6 with respect to all the loads 5, respectively.

If the radially outer end of the turntable 1 is lifted upward, the moment load acting on the rotation guide mechanism 4 can be reduced. Therefore, the diameter of the rolling bearing 4c used for the rotation guide mechanism 4 can be reduced, the rotation guide mechanism 4 can be reduced in size, weight, and the center of gravity can be reduced.
Furthermore, since the bending deformation of the turntable 1 can be suppressed as described above, the turntable 1 can be thinned. In particular, when the rotary table 1 has a large diameter, the rotary table 1 is likely to bend and deform. However, even in such a case, the thickness of the rotary table 1 is increased to suppress the bending deformation. There is no need to increase rigidity. Therefore, since the turntable 1 can be thinned, the turntable device can be made thin even when the turntable 1 has a large diameter.

  In the conventional product that does not include the above-mentioned advance / retreat mechanism in the air pad, if the accuracy of the bearing guide surface of the rotary table is low, the clearance (bearing clearance) between the gas bearing surface and the bearing guide surface is reduced as the rotary table rotates. There is a possibility that the size may fluctuate. For example, when the bearing gap increases, the force directed downward in the vertical direction of the gas bearing surface applied to the bearing portion by the static pressure gas bearing decreases, so the force directed upward in the vertical direction applied to the rotary table also decreases. There is a risk that the radially outer end of the rotary table bends and deforms downward. In addition, when the bearing gap becomes smaller, the force directed downward in the vertical direction of the gas bearing surface applied to the bearing portion by the static pressure gas bearing increases, so the force directed upward in the vertical direction applied to the rotary table also increases. There is a risk that the radially outer end of the rotary table bends upward and deforms.

  However, the rotary table device of the present embodiment includes an advance / retreat mechanism that advances and retracts the bearing portion 10 in the direction perpendicular to the gas bearing surface 10a, so that the accuracy of the bearing guide surface 1a of the rotary table 1 is low and the movement of the rotary table 1 is low. Accordingly, even if the size of the gap (bearing gap) between the gas bearing surface 10a and the bearing guide surface 1a fluctuates, the rotary table 1 is less likely to bend and deform, and the distance between the rotary table 1 and the base 2 ( Vertical distance) is kept constant. Therefore, the rotary table 1 can be rotated in a stable posture.

  This mechanism will be described in detail below. For example, when the bearing gap becomes large due to insufficient accuracy of the bearing guide surface 1a of the rotary table 1, the force directed downward in the vertical direction of the gas bearing surface 10a applied to the bearing portion 10 by the static pressure gas bearing becomes small. However, if so, the balance between the urging force by the air spring and the force by the static pressure gas bearing is lost, and the bearing portion 10 moves upward by the urging force directed upward in the vertical direction of the gas bearing surface 10a by the air spring (ie, The vertical length of the air pad 6 is increased). And the bearing part 10 is hold | maintained in the recessed part 11a of the housing part 11 in the height position where the urging | biasing force by an air spring and the force by a static pressure gas bearing balance.

  On the contrary, when the bearing clearance is reduced, the force directed downward in the vertical direction of the gas bearing surface 10a applied to the bearing portion 10 by the static pressure gas bearing is increased. The balance with the force by the bearing is lost, and the bearing portion 10 moves downward by the force directed downward in the vertical direction of the gas bearing surface 10a applied to the bearing portion 10 by the hydrostatic gas bearing (that is, the vertical length of the air pad 6). Is smaller). And the bearing part 10 is hold | maintained in the recessed part 11a of the housing part 11 in the height position where the urging | biasing force by an air spring and the force by a static pressure gas bearing balance.

  As described above, when the bearing gap is increased, the vertical length of the air pad 6 is increased by moving the bearing portion 10 upward, and when the bearing gap is decreased, the air pad 6 is moved downward. Therefore, even if the bearing gap fluctuates with the rotation of the turntable 1, the gas bearing surface of the air pad 6 that is initially set according to the weight of the turntable 1, the mass of the load, etc. The distance (vertical distance) between the rotary table 1 and the base 2 is kept constant without adjusting the gas ejection pressure from 10a in accordance with the change in the bearing gap. Therefore, the rotary table 1 can always be rotated in a stable posture without being affected by the accuracy of the bearing guide surface 1a.

Therefore, since it is not necessary to manage the accuracy of the bearing guide surface 1a of the turntable 1 with high accuracy, it is possible to reduce the cost of manufacturing the parts of the turntable device. Further, even if the reference surface (for example, the gas bearing surface 10a) of the air pad 6 is deformed due to thermal deformation, deformation over time, deformation during initial assembly, deformation of the installation surface (the upper surface of the base 2) due to load, etc. The distance (vertical direction distance) between the rotary table 1 and the base 2 is kept constant by the mechanism.
In addition, about the advance / retreat mechanism, the following modifications can be employed. For example, as shown in FIG. 2, the advance / retreat mechanism can be configured by using a coil spring 20 instead of an air spring (first modification). The first modification will be described in detail below.

  In the example of FIG. 2, a coil spring 20 is disposed as a forward / backward mechanism in a bottomed hole 22 formed in the center of the bottom surface of the recess 11 a of the housing portion 11, and the coil spring 20 is connected to the housing portion 11 and the bearing. An urging force in the vertical direction of the gas bearing surface 10 a is applied to the portion 10. More specifically, the coil spring 20 applies a biasing force directed downward in the vertical direction of the gas bearing surface 10a to the housing portion 11, and applies a biasing force directed upward in the vertical direction of the gas bearing surface 10a to the bearing portion 10. The spring constant of the coil spring 20 may be appropriately selected according to the strength of the urging force to be applied to the bearing portion 10 (that is, the force to be applied to the rotary table 1).

  In the first modification, an adjustment mechanism that adjusts the urging force of the coil spring 20 may be provided. FIG. 3 shows an example (second modified example) in which a spacer 21 is used as the adjusting mechanism. That is, if the compression amount of the coil spring 20 is adjusted by arranging, for example, an annular spacer 21 between the bottom of the bottomed hole 22 and the coil spring 20, the strength of the urging force can be adjusted. Further, the strength of the biasing force can be adjusted by adjusting the thickness of the spacer 21 and the vertical position where the spacer 21 is provided.

  Moreover, as shown in FIG. 4, the coil spring 20 and the air spring by gas supply can also be used together as an advancing / retreating mechanism (third modification). If the bottomed hole 22 provided with the coil spring 20 is sealed with an O-ring 17 or the like, and the gas is supplied to the space of the sealed bottomed hole 22 to make a positive pressure, the housing portion is applied by the biasing force of the coil spring 20 and the air spring. 11 and the bearing portion 10 can be applied with an urging force in the vertical direction of the gas bearing surface 10a. Further, by adjusting the pressure in the space of the bottomed hole 22, the strength of the urging force in the vertical direction of the gas bearing surface applied to the housing part 11 and the bearing part 10 can be reduced without using the spacer 21. Can be adjusted.

  In addition, since supply of the gas to the space of the bottomed hole 22 may not be stable and the pressure in the space of the bottomed hole 22 may become unstable, it is applied to the housing portion 11 and the bearing portion 10. In order to stabilize the strength of the urging force in the vertical direction of the gas bearing surface 10a, it is preferable to apply the urging force with the coil spring 20 as a main component. Further, when the rotary table device is used under a positive pressure or negative pressure condition, the pressure in the space of the bottomed hole 22 may fluctuate, so that the gas applied to the housing part 11 and the bearing part 10 In order to stabilize the strength of the urging force in the vertical direction of the bearing surface 10a, it is preferable to apply the urging force with the coil spring 20 as a main component.

Such a rotary table device of this embodiment includes an exposure device (for example, a semiconductor exposure device for forming a pattern on a flat substrate such as a semiconductor wafer or a liquid crystal panel), an assembly device, an inspection device (for example, a microscope), a precision device. It can be used as a positioning device used for machine tools and the like.
For example, an exposure apparatus that exposes a semiconductor wafer to form a pattern places a semiconductor wafer, which is a material to be exposed, and rotates to position the semiconductor wafer, and irradiates the positioned semiconductor wafer with exposure light. An optical system and a control device for controlling them are provided. As the positioning device, the rotary table device of the present embodiment is preferably used.

When the rotary table device with the wafer placed on the rotary table is driven to move the wafer to a predetermined position, exposure is performed by irradiating the wafer with exposure light from the light source of the optical system to form a pattern on the wafer. . When the exposure is completed, the rotary table device is driven to move another wafer to a predetermined position, exposure is performed in the same manner as described above, and a pattern is formed on the wafer.
The rotary table device of the present embodiment used as a positioning device in such an exposure apparatus is unlikely to cause deformation of the rotary table and can rotate the rotary table in a stable posture, so that the exposure apparatus can accurately position the material to be exposed. It is.

  Further, the microscope includes a positioning device that places and rotates the test sample 8 to position the test sample 8, an optical system that observes the positioned test sample 8, and a control device that controls these. (See FIG. 5). As the positioning device, the rotary table device of the present embodiment is preferably used. When the rotary table device having the test sample 8 placed on the rotary table 1 is driven to move the test sample 8 to a predetermined position, the test sample 8 is observed using an optical system.

  Since the rotary table device of the present embodiment used as a positioning device in such a microscope can hardly rotate the rotary table 1 and can rotate the rotary table 1 in a stable posture, the microscope can position the test sample 8. Is accurate. Further, if the gas ejection pressure from the gas bearing surface 10a of the air pad 6 is changed, the distance (vertical direction distance) between the rotary table 1 and the base 2 can be adjusted, so that the focus of the microscope is adjusted by the gas ejection pressure. Can be combined.

  That is, if the gas ejection pressure is increased, the upward force applied to the turntable 1 also increases, and the portion of the turntable 1 facing the air pad 6 is bent upward and deformed. The height position rises. On the contrary, if the gas jet pressure is weakened, the upward force applied to the turntable 1 is also reduced, and the portion of the turntable 1 facing the air pad 6 is bent downward and deformed, and the upper surface of that portion The height position of descents.

  Therefore, if the air pad 6 is arranged at a position facing the objective lens 9 of the optical system of the microscope, the portion facing the objective lens 9 of the turntable 1 (outside in the radial direction in FIG. 5) due to the gas ejection pressure as described above. The microscope can be focused by adjusting the height position of the upper surface of the end portion. In the rotary table device applied to the microscope, the number of air pads 6 may be one as shown in FIG. 5 or may be plural.

  In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. For example, in the present embodiment, the rotary table device has been described as an example of the moving table device. However, the present invention is not limited to this, and the present invention is based on a guide mechanism that guides the linear movement of the moving table. The present invention can also be applied to an XY table device that moves a supported moving table in two orthogonal directions. The present invention can also be applied to a linear table device that linearly moves the moving table in one direction.

The type of spring is not limited to a coil spring or an air spring, and other types of springs such as a leaf spring can be used. Also, a spring made of a lump of elastic material such as rubber can be used. Furthermore, the material of the coil spring and the leaf spring is not limited to metal, and resin material, wood, bamboo, or the like can also be used.
In addition to the self-contained throttles shown in FIGS. 1 to 5, there are other types of throttles for hydrostatic gas bearings, such as orifice throttles, surface throttles, and porous throttles. Any type can be used in the present invention. is there. However, among these, the self-contained drawing is preferable because it uses a drill hole as a drawing and is easy to manufacture.

DESCRIPTION OF SYMBOLS 1 Rotation table 1a Bearing guide surface 2 Base 4 Rotation guide mechanism 6 Air pad 10 Bearing part 10a Gas bearing surface 10b Spout 11 Housing part 11a Recess 20 Coil spring 21 Spacer 22 Bottomed hole 24 Bottomed hole

Claims (4)

A base, a moving table that linearly moves or rotates on the base, and a linear movement or rotation of the moving table that is arranged between the base and the moving table while supporting the moving table on the base. A moving table device comprising a guide mechanism,
A bearing guide surface of the static pressure gas bearing is provided on a surface facing the base of the moving table,
The bearing guide surface and the gas bearing surface are provided by having a gas bearing surface formed with an ejection port for ejecting gas, and ejecting gas from the gas bearing surface toward the bearing guide surface facing the bearing gap. An air pad capable of constituting a static pressure gas bearing between the base and the gas pad is fixed to a surface of the base facing the moving table with the gas bearing surface facing the bearing guide surface,
The air pad includes a bearing portion including the gas bearing surface, and a housing portion that is fixed to the base and holds the bearing portion, and the housing portion is configured such that the gas bearing surface is exposed. Holding the bearing portion in the recess so as to be able to advance and retreat in the direction perpendicular to the gas bearing surface,
The air pad further includes an advance / retreat mechanism that advances and retracts the bearing portion in the vertical direction of the gas bearing surface to maintain a constant vertical distance between the move table and the base. .   The said advancing / retreating mechanism is a spring that is arranged between the housing part and the bearing part and applies a biasing force in a direction perpendicular to the gas bearing surface to the housing part and the bearing part. 2. The moving table device according to 1.   The moving table device according to claim 2, wherein the spring is at least one of a coil spring and an air spring.   The moving table device according to claim 2, wherein the advance / retreat mechanism includes an adjustment mechanism that adjusts an urging force of the spring.

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