JP3963066B2 - Stage device with overrun sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stage device that moves three axes of XYθ that can be applied to various machines and instruments such as an optical machine such as an exposure apparatus, a measuring instrument, a machine tool, and a screen printing machine. The present invention relates to a stage apparatus equipped with an overrun sensor for preventing the movement of the stage.
[0002]
[Prior art]
As a stage device that performs movement control in the X, Y, and θ directions using one stage, for example, a device disclosed in Japanese Patent Application Laid-Open No. 8-25163 has been proposed.
FIG. 8 is a diagram showing the configuration of the stage device, and FIG. 8B shows a cross-sectional view taken along the line AA of FIG.
In the figure, a stage 20 is placed on a base 21 via a flat guide 22 so as to be movable in the XYθ directions. In the following, as shown in the figure, the X direction is referred to as the left-right direction in the figure, the Y direction is referred to as the up-down direction in the figure, and “moving in the θ direction” means to rotate around an axis perpendicular to the XY plane. To tell.
A central portion of the stage 20 and the base 21 is provided with a through window. For example, the mask is placed on the stage 20 and the mask is irradiated with light from a light source (not shown) and placed on a work stage (not shown). Performs exposure processing of workpieces.
Reference numerals 23, 24, and 25 denote first to third driving elements. The driving elements 23, 24, and 25 include actuators such as motors, the driving units 23a and 24a are in the X direction, and the driving unit 25a is in the Y direction. To drive. Slide shafts 23b, 24b, and 25b are attached to the drive units 23a, 24a, and 25a, and the slide shafts 23b, 24b, and 25b are driven and driven elements attached to the arms 20a, 20b, and 20c of the stage 20. The slide members 23c, 24c, and 25c are engaged.
[0003]
FIG. 9 shows the mounting structure of the slide shafts 23b, 24b, 25b and the rotation and slide members 23c, 24c, 25c. The rotation and slide members 23c, 24c, and 25c are rotatably attached to the arms 20a, 20b, and 20c via shafts 23d, 24d, and 25d. The rotation and slide members 23c, 24c, and 25c are connected to the slide shaft 23b, It can slide in the direction of the arrow in FIG.
[0004]
Returning to FIG. 8, reference numeral 26 denotes a spring. One end of the spring 26 is fixed, and the other end biases the arms 20 a, 20 b, and 20 c of the stage 20 in the direction of the drive elements 23, 24, and 25.
In FIG. 8, the stage 20 is driven as follows.
When the stage 20 is moved in the X direction, the first and second drive elements 23 and 24 are driven to move the drive units 23a and 24a by an equal amount in the X direction in the figure. Accordingly, the rotation and slide member 25c attached to the arm 20c of the stage 20 slides along the slide shaft 25b, and the stage 20 moves in the X direction.
In order to move the stage 20 in the Y direction, the first and second driving elements 23 and 24 are not driven, but the third driving element 25 is driven and the driving unit 25a is moved. Accordingly, the rotation and slide members 23c and 24c attached to the arms 20a and 20b of the stage 20 slide along the slide shafts 23b and 24b, and the stage 20 moves in the Y direction.
[0005]
When the stage 20 is moved (rotated) in the θ direction, the first and third drive elements 23 and 25 move the drive units 23a and 25a in the first direction (for example, the drive units 23a and 25a are Driving in the direction in which the arms 20a and 20c of the stage 20 are pushed, and the third driving element 24 causes the driving unit 24a to move in a direction opposite to the first direction (for example, the driving unit 24a pulls the arm 20b of the stage 20). ) To drive. For example, when the stage is rotated clockwise, the drive unit 23a is driven in the + X direction, the drive unit 25a is driven in the + Y direction, and the drive unit 24a is driven in the -X direction. Here, the + direction refers to the direction in which the driving element pushes the arm, and the − direction refers to the direction in which the driving element pulls the arm. Thereby, the stage 20 is centered on the intersection of the line A1 connecting the shafts 23d and 24d of the rotation and slide members 23c and 24c and the line A2 passing through the shaft 25d of the rotation and slide member 25c and orthogonal to the moving direction of the drive unit 25a. (This center of rotation is referred to as a reference axis).
[0006]
[Problems to be solved by the invention]
In the stage apparatus, when the drive elements 23, 24, and 25 cannot be controlled by the control apparatus, the stage 20 moves more than necessary (overruns), contacts other parts of the apparatus, or drives It may continue to move beyond the mechanical movement range of the element, causing damage to each part.
As a means for preventing overrun, a movement restricting means, that is, an overrun sensor is generally provided. For example, transmission type overrun sensors are provided at both ends of the driving elements 23, 24, 25 in the moving direction of the driving elements 23, 24, 25, and the driving parts 23a, 24a, 25a of the driving elements 23, 24, 25 are provided. Is provided with a dog for shielding the sensor.
The drive units 23a, 24a, and 25a of the drive elements 23, 24, and 25 move within a range sandwiched between the sensors. If the drive element attempts to move beyond the range, the dog is overrun sensor. The overrun sensor sends a dog detection signal to the control unit, and the control unit stops the movement of the drive elements 23, 24, 25.
[0007]
However, in the case of a stage apparatus as shown in Japanese Patent Application Laid-Open No. 8-25163, each drive element 23, 24, 25 serves both as a movement in the X or Y direction and a movement in the θ direction. Therefore, the X or Y direction movement and the θ direction movement of the stage cannot be detected independently only by providing two sensors in the moving direction of the driving elements 23, 24, and 25 as described above.
For example, as shown in FIG. 10A, for the movement of the stage 20 in the X direction, a dog D is provided in one of the drive elements 23 or 24, and two sensors S1 and S2 are provided in the X direction. It is assumed that the movement range in the X direction of the driving element (stage) is set.
This range is sufficient for the movement of the stage 20 in the X direction. However, the stage 20 shown in FIG. 8 also moves in the θ direction.
For this reason, when the stage moves in the X direction and then moves in the θ direction, as shown in FIG. 10B, if the drive element is approaching near the end of the moving range in the X direction, the stage 20 is moved in the θ direction. However, the dog D shields the sensor S2 from light even though the movement in the θ direction is actually possible, and the movement of the stage 20 stops. On the other hand, if the positions of the sensors S1 and S2 are moved, for example, so that the θ movement of the stage is possible even in such a case, an overrun cannot be detected for the movement in the X direction.
[0008]
The present invention has been made in view of the above circumstances, and in a stage apparatus that moves a stage in the XYθ directions by three driving elements, an overrun in the X, Y, and θ directions of the stage is independently detected to detect the stage. To provide a stage apparatus provided with an overrun sensor that can ensure normal operation.
[0009]
[Means for Solving the Problems]
In the present invention, the above-described problems are solved as follows.
First and second driving elements for moving the stage in a first direction perpendicular to the first plane in a plane perpendicular to the reference axis are provided on a first plane including the reference axis. In addition, a third driving element is provided on a second plane that includes the reference axis and intersects the first plane, and the first, second, and third driving elements are used with respect to the reference axis. A stage device that linearly moves the stage in a first plane orthogonal to the first plane and a second direction orthogonal to the second plane in a vertical plane and rotates about the reference axis In the above, the movement amount of the stage in the first direction and the second direction is limited and the rotation amount of the stage around the reference axis is limited as follows.
(1) Linear movement amount restriction At least two first detection members (dogs) arranged in parallel with the stage surface and formed in an arc shape with the reference axis as the center, each arc is connected to the reference It is attached to the stage so as to cross a straight line passing through the axis and parallel to the first and second directions.
A first sensor for detecting the position of the first detected member (dog) is provided, and the movement of the stage in the first and second directions is limited by the sensor output.
(2) Rotation amount limitation A second detection member driven by the first driving element and a second sensor driven by the second driving element, and the first and second of the stage The relative position of the second detected member and the second sensor does not change with respect to movement in two directions (for example, the X and Y directions), and the second rotation is performed when the stage rotates around the reference axis. A means for moving the detected member and the sensor in directions away from each other is provided, and movement in the rotational direction of the stage is detected by the output of the second sensor.
The above-mentioned means may be constituted by, for example, a mechanism for detecting a difference between the movement amounts of the first and second driving elements and a sensor for generating an output when the difference between the movement amounts exceeds a predetermined value. The movement of the rotation direction of the stage is detected by the output of the sensor.
In the present invention, since the movement amount detection and rotation amount detection of the stage are performed as described above, the movement amount of the stage in the first and second directions and the rotation amount around the reference axis are detected independently. In addition, the movement amount and the rotation amount can be limited.
Therefore, it is possible to ensure normal operation of the stage device that linearly moves and rotates the stage by the three driving elements.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing a configuration of a stage apparatus having an overrun sensor composed of a dog and a sensor corresponding to movement in the X, Y, and θ directions according to an embodiment of the present invention, and FIG. The AA sectional drawing of is shown. FIG. 1 shows an embodiment in which the overrun sensor of the embodiment of the present invention is attached to the stage apparatus shown in FIG. 8. The same components as those shown in FIG. 8 are denoted by the same reference numerals.
In the figure, a stage 20 is placed on a base 21 via a flat guide 22 so as to be movable in the XYθ directions.
Reference numerals 23, 24, and 25 denote first to third drive elements. As described above, the slide shafts 23b, 24b, and 25b are attached to the drive units 23a, 24a, and 25a, and the slide shafts 23b, 24b, and 25b are The rotation and slide members 23c, 24c, and 25c attached to the arms 20a, 20b, and 20c of the stage 20 are engaged.
[0011]
The mounting structure of the slide shafts 23b, 24b, 25b and the rotation and slide members 23c, 24c, 25c is the same as that shown in FIG. 9, and the rotation and slide members 23c, 24c, 25c are arms 20a, 20b, 20c. The rotary and slide members 23c, 24c, and 25c are slidable in the direction of the arrow in the figure along the slide shafts 23b, 24b, and 25b. is there.
Reference numeral 26 denotes a spring. As described above, one end of the spring 26 is fixed, and the other end is urged so as to press the arms 20a, 20b, 20c of the stage 20 in the direction of the drive elements 23, 24, 25. Yes.
[0012]
The stage apparatus shown in FIG. 1 is driven as follows, similarly to the one shown in FIG.
When the stage 20 is moved in the X direction, the first and second drive elements 23 and 24 are driven to move the drive units 23a and 24a by an equal amount in the X direction in the figure. Further, in order to move the stage 20 in the Y direction, the first and second driving elements 23 and 24 are not driven, but the third driving element 25 is driven to move the driving unit 25a.
Further, when the stage 20 is moved in the θ direction (rotated about the reference axis), the first and second drive elements 23 and 25 are used to drive the drive units 23a and 25a, respectively, as described above. The drive unit 24a is driven in the direction (for example, the direction in which the drive units 23a and 25a push the arms 20a and 20c of the stage 20), and the third drive element 24 moves the drive unit 24a in the direction opposite to the first direction (for example, the drive unit 24a). Is driven in the direction of pulling the arm 20b of the stage 20). Thereby, the stage 20 rotates around the above-described reference axis.
[0013]
In this embodiment, the stage apparatus is provided with the following overrun sensor.
In FIG. 1, a dog 1 that forms a circular arc centered on the reference axis is provided in the direction of the first plane (plane perpendicular to the stage surface) including the reference axis of the stage 20 (this is referred to as an X moving dog). To do). X direction sensors 2 a and 2 b are provided on the bases 21 on both sides in the X direction of the X moving dog 1.
In addition, in the second plane direction including the reference axis of the stage 20 (the second plane is orthogonal to the first plane), a dog 3 is formed that forms a circular arc centered on the reference axis (Y motion). Dog). Y direction sensors 4 a and 4 b are provided on the bases on both sides in the Y direction of the Y moving dog 3. An overrun in the X direction and Y direction of the stage 20 is detected by the X moving dog 1 and the Y moving dog 3, the X direction sensors 2a and 2b, and the Y direction sensors 4a and 4b.
[0014]
FIG. 2 shows an enlarged view of the X moving dog 1 (or Y moving dog 3) and the sensors 2a and 2b (or sensors 4a and 4b).
The sensors 2a and 2b are transmissive sensors and have a U shape. For example, a light receiving element 31a is provided on a lower projection of the U shape, and a light emitting element 31b is provided on an upper projection of the U shape. Is provided. During operation, the light from the light emitting element 31a is always received by the light receiving element 31b. When a light shielding object is inserted between the U-shaped projections and the light is blocked, a detection signal for the light shielding object is output. This light shielding object for the sensor is called a dog here.
[0015]
Returning to FIG. 1, the driving units 23a and 24a of the first and second driving elements 23 and 24 provided on the first plane including the reference axis of the stage are moved by the movement of the driving units 23a and 24a in the X direction. Push rods 5 and 6 that are pushed at one end and move linearly are provided.
When the stage 20 is moved in the Y direction by the drive element 25, the drive units 23a and 24a move parallel to the contact surfaces of the push rods 5 and 6 and the drive units 23a and 24a.
At the other end of the two push rods 5 and 6, there are provided rotation bars 7 and 8 for converting linear motion of the push rods 5 and 6 into rotational motion, respectively. The rotation bars 7 and 8 are rotated about the rotation shafts 7a and 8a by pushing one ends of the rotation bars 7 and 8 by the push rods 5 and 6, respectively. At the end where the rotary bars 7 and 8 are in contact with the push rods 5 and 6, a spring 9 is provided for pressing the end against the push rod.
[0016]
On the other end side of the rotating bar 7, a dog 7b (referred to as a θ moving dog) is provided. On the other end side of the rotating bar 8, two sensors 8b (referred to as a θ sensor) are provided so as to sandwich the dog 7b. Is provided. Hereinafter, the rotating bar 7 provided with the θ moving dog 7b is referred to as a dog bar, and the rotating bar provided with the θ sensor 8b is referred to as a sensor bar. An overrun in the θ direction of the stage 20 is detected by the θ dog 7 b of the dog bar 7 and the θ sensor 8 b of the sensor bar 8.
FIG. 3 shows an enlarged view of a portion composed of the θ moving dog 7b and the two θ sensors 8b. The θ sensor 8b is a U-shaped sensor similar to the X direction sensors 2a and 2b and the Y direction sensors 4a and 4b, and the dog (light shielding plate) is detected by being shielded from light by the θ moving dog 7b. The
[0017]
Next, the overrun detection operation of the stage apparatus of this embodiment will be described.
In FIG. 4, the stage 20 moves in the X direction (right direction in the drawing) and the Y direction (upward direction in the drawing), the X moving dog 1 approaches the X direction sensor 2b, and the Y moving dog 3 approaches the Y direction sensor 4b. Indicates the state. When the stage 20 further moves in the X direction or the Y direction, the X moving dog 1 or the Y moving dog 3 turns off the X direction sensor 2b or the Y direction sensor 4b.
The outputs of the X direction sensors 2a and 2b or the Y direction sensors 4a and 4b are supplied to a control device (not shown). When the X moving dog 1 or the Y moving dog 3 turns off the X direction sensor 2b or the Y direction sensor 4b, a control (not shown) is performed. The apparatus stops the movement of the stage 20 and prevents overrun.
[0018]
On the other hand, when the stage 20 moves in the X direction, the drive portions 23a and 24a of the two arms 23 and 24 provided on the same plane passing through the reference axis push the push rods 5 and 6 in contact with each other in the same direction.
For this reason, as shown in FIG. 4, the dog bar 7 and the sensor bar 8 rotate in the same direction, and the positional relationship between the θ dog 7b and the θ sensor 8b is kept almost the same as before the stage movement. Even if the stage 20 moves in the Y direction, the drive units 23a and 24a of the arms 23 and 24 only move in parallel with respect to the contact surface between the push rods 5 and 6 and the drive units 23a and 24a. The positional relationship between the dog 7b and the θ sensor 8b does not change. That is, the θ direction overrun sensor does not operate when the stage 20 moves in the X direction or Y direction.
Therefore, the stage can be moved in the θ direction within the set range from the state of FIG.
[0019]
FIG. 5 shows a case where the stage 20 moves in the θ direction and the θ dog 7b cuts one of the θ sensors 8b.
When the stage 20 moves in the θ direction, as shown in FIG. 5, only one of the two push rods 5 and 6 is pushed to move in the X right direction (+ X direction) in the figure, and the other one When pushed by the spring 9, it moves in the left direction (−X direction) in the drawing X.
Therefore, the dog bar 7 and the sensor bar 8 rotate in opposite directions, and one of the θ dog 7b and the θ sensor 8b approaches. When the stage 20 further rotates in the same direction, the θ dog 7b cuts the θ sensor 8b as shown in FIG. 5, and the movement of the stage 20 is stopped as described above to prevent overrun.
[0020]
Here, even if the stage 20 moves in the θ direction, the X moving dog 1 and the Y moving dog 3 form a circular arc drawn around the reference axis that is the rotation axis of the stage 20 as described above. Therefore, the positional relationship between the X moving dog 1 and the X direction sensors 2a and 2b and the positional relationship between the Y moving dog 3 and the Y direction sensors 4a and 4b do not change.
That is, when the stage 20 moves in the θ direction, the overrun sensor in the X or Y direction does not operate, and after moving in the θ direction, the stage further moves in the X or Y direction. However, it is possible to accurately detect an overrun in the X direction or the Y direction.
[0021]
In the present embodiment, the dogs 1 and 3 arranged in parallel to the stage surface as described above and formed in an arc shape with the reference axis as the center are arranged so that the tangent line of the arc is parallel to the X and Y directions. A first sensor 2a, 2b, 4a, 4b that is attached to the stage 20 and detects the positions of the dogs 1, 3 is provided, and the outputs of the sensors 2a, 2b, 4a, 4b are used in the XY direction of the stage 20 It comprises a dog 7b driven by the first driving element 23 and a second sensor 8b driven by the second driving element 24 in the X and Y directions of the stage. When the stage 20 rotates around the reference axis, the dog 7b and the second sensor 8b move away from each other when the relative position between the dog 7b and the second sensor 8b does not change. Stage 20 A rotation amount detecting means is provided, since to carry out the movement restriction of the rotational direction by the output of the second sensor 8b, it is possible to detect independently the XY direction of overrun and θ direction overrun.
[0022]
In the above embodiment, a case has been described in which one arcuate X moving dog 1 and one Y moving dog 3 are provided as the overrun detection means in the XY direction. FIG. 6 shows the X moving dog and the Y moving dog. Alternatively, two of them may be provided.
That is, as shown in FIG. 6, X-moving docks 1 a and 1 b formed in an arc shape around the reference axis are provided on both sides of the stage 20, and X-direction sensors 2 a and 2 b are arranged on both sides of the stage 20. Similarly, Y-moving dogs 3 a and 3 b formed in an arc shape with the reference axis as the center are provided on the upper and lower sides of the stage 20, and Y-direction sensors 4 a and 4 b are arranged on the upper and lower sides of the stage 20. Even with this configuration, the overrun in the XY directions of the stage 20 can be detected as in FIG. In FIG. 6, the push rods 5, 6, the dog bar 7, the sensor bar 8, and the like are omitted.
[0023]
FIG. 7 is a view showing a modification of the above-described embodiment, and this embodiment shows an embodiment in which the dog bar 11 and the sensor bar 12 are translated without rotating. In the present embodiment, the driving element and the arm are composed of a flat plate and a roller. In FIG. 7, reference numerals 23, 24, and 25 denote first to third drive elements, and the drive portions 23a, 24a, and 25a of the drive elements 23, 24, and 25 are formed in a flat plate shape, and the arm 20a. , 20b and 20c are in contact with rollers 23e, 24e and 25e.
[0024]
The stage apparatus shown in FIG. 7 is similar to that shown in FIG. 1, by driving the first and second drive elements 23, 24 and moving the drive units 23 a, 24 a by an equal amount, the stage 20 Is moved in the X direction, the stage 20 is moved in the Y direction by driving the third driving element 25 and moving the driving unit 25a without driving the first and second driving elements 23 and 24. Let
Furthermore, the first and second drive elements 23 and 25 drive the drive units 23a and 25a in the first direction, respectively, and the third drive element 24 and the drive unit 24a are opposite to the first direction. By driving in the direction, the stage 20 can be rotated around the reference axis.
[0025]
As an overrun detection mechanism in the θ direction, as in FIG. 1, the push bar 5 is linearly moved by pushing one end by the movement in the X direction of the drive units 23a, 24a of the first and second drive elements 23, 24. , 6 are provided.
When the stage 20 is moved in the Y direction by the drive element 25, the drive units 23a and 24a move parallel to the contact surfaces of the push rods 5 and 6 and the drive units 23a and 24a.
Bars 11 and 12 are fixed to the other ends of the two push rods 5 and 6, and when the push rods 5 and 6 move, the bars 11 and 12 move in the same direction as the push rods 5 and 6. On the other end side of the bars 11 and 12, as in FIG. 1, the θ moving dog 7b and the two θ sensors 8b are provided so as to sandwich the dog.
[0026]
In FIG. 7, when the stage 20 moves in the X direction, the bars 11 and 12 move in parallel in the same direction as described above, and the relative positions of the bars 11 and 12 do not change. When the stage 20 moves in the Y direction, the drive units 23a and 24a move parallel to the contact surfaces of the push rods 5 and 6 and the drive units 23a and 24a, and similarly the relative positions of the bars 11 and 12 Will not change.
When the stage 20 rotates, only one of the two push rods 5 and 6 is pushed and moves to + a in the X right direction in the figure, and the other is pushed by the spring 9 to the left in the drawing X direction. Move to -a. Since the bars 11 and 12 move parallel to each other in the opposite direction, the relative movement amount of the bars 11 and 12 becomes 2a, the θ dog 7b cuts the θ sensor 8b, and the movement of the stage is stopped and overrun is performed as described above. prevent.
[0027]
【The invention's effect】
As described above, in the present invention, the following effects can be obtained.
(1) In a stage apparatus that controls the movement of one stage in the X, Y, and θ directions using the first, second, and third driving elements, the rotation axis of the stage is used as movement limiting means in the XY directions. A first and second drive provided on a plane including the rotation axis of the stage as a movement restriction means in the XY direction by restricting movement in the X and Y directions by a combination of an arcuate dog and a sensor at the center. Since the movement difference in the θ direction is limited by detecting the difference in the movement amount of the elements by the sensor, the overrun in the X, Y, θ direction of the stage can be detected independently. Normal movement can be ensured.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a stage apparatus including an overrun sensor according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a portion of an X moving dog / Y moving dog and a sensor.
FIG. 3 is a partially enlarged view of a θ moving dog and a θ sensor.
FIG. 4 is a diagram illustrating a state in which the stage has moved in an X direction and a Y direction.
FIG. 5 is a diagram illustrating a state in which a stage is rotated.
FIG. 6 is a diagram showing another configuration example of the overrun detection means in the XY directions.
FIG. 7 is a diagram showing a modification of the first embodiment.
FIG. 8 is a diagram illustrating a configuration example of a stage apparatus that performs movement control in the X, Y, and θ directions using one stage.
FIG. 9 is a view showing a slide shaft and a rotation and slide member mounting structure.
FIG. 10 is a diagram illustrating a problem when a conventional stage apparatus is provided with a dog and two sensors to detect a movement amount.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 X moving dog 2a, 2b X direction sensor 3 Y moving dog 4a, 4b Y direction sensor 5, 6 Push bar 7 Rotation bar (dog bar)
7b Dog (θ moving dog)
8 Rotating bar (sensor bar)
8b Sensor (θ sensor)
11, 12 bar 20 stage 21 base 22 planar guides 23, 24, 25 first to third drive elements 23a, 24a, 25a drive units 23b, 24b, 25b slide shafts 20a, 20b, 20c arms 23c, 24c, 25c Rotating and sliding member

Claims (1)

First and second driving elements for moving the stage in a first direction perpendicular to the first plane in a plane perpendicular to the reference axis are provided on a first plane including the reference axis. And a third linearly moving in a second direction perpendicular to the second plane within a plane perpendicular to the reference axis on a second plane that includes the reference axis and intersects the first plane . The drive element of
The first, second, and third driving elements cause the stage to be orthogonal to the first plane and to the second plane in a plane perpendicular to the reference axis. with linearly moves in a second direction, a stage device for rotating about said reference axis, arranged parallel to the stage surface, at least two, which are formed in an arc shape about said reference axis A first detected member (dog) is attached to the stage so that each arc intersects a straight line passing through the reference axis and parallel to the first and second directions, and the position of the first detected member A first sensor for detecting the movement is detected, and the movement of the stage in the first and second directions is detected based on the sensor output;
A second sensor member driven by the first driving element; and a second sensor driven by the second driving element, in the first and second directions of the stage. The relative position between the second detected member and the second sensor does not change with respect to the movement of the second detected member. When the stage rotates around the reference axis, the second detected member and the second sensor A stage apparatus provided with an overrun sensor, characterized in that means for moving in a separating direction is provided, and movement in the rotational direction is detected by the output of the second sensor.

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