JPH1123751A - Xytheta stage and controller of the xytheta stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of stage positioning in moving in the direc tion X or direction Y and two directions of X and Y in an θ stage. SOLUTION: This XYθ stage has a table 3 put on the horizontal slide 2 of a base 1 and movable in X, Y and θ directions, 3 actuators 4, 5 and 6 driving the table 3 in X, Y and θdirections and feed screw units 10, 11 and 12 transmitting the drive motions of the actuators 4, 5 and 6. In this case, the actuators 4, 5 and 6 are freely movable in directions X and Y on the guides 13, 14 and 15 fixed to the base 1 and three supporting points 7, 8 and 9 subsequently moved along the guides 13, 14 and 15 following the drive of other actuators 4, 5 and 6 and connecting the feed screw units 10, 11 and 12 to the table 3 of actuators 4, 5 and 6 are set on the fixed position on the table 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray detector used for positioning a work to be inspected in various inspection apparatuses and the like.
Related to the Yθ stage. Here, X and Y indicate the directions of the respective axes of the XY coordinates on the horizontal plane, and θ is the angle of rotation on the horizontal plane about the coordinates of the rotation center of the XY coordinates or the X-axis due to the rotation. Alternatively, it indicates the angle of inclination with respect to the Y axis.

[0002]

2. Description of the Related Art A conventional XYθ stage has a configuration in which each stage is stacked on an X stage, such as a Y stage, and further on the Y stage, a θ stage. In such a conventional type, the height of the entire stage cannot be reduced, and it is difficult to reduce the weight. It is difficult to increase the speed because of the weight. When the stage becomes large in size, there is a problem that the table of the component parts bends by its own weight.

In order to solve these drawbacks and problems, recently, improved tables have been put to practical use. The improved table includes a base having a water-smoothing section, a table mounted on the water-smoothing section of the base and movable in X, Y, and θ directions, and three tables for driving the table in orthogonal and rotational directions. It is assembled by the actuator and the like.

[0004] An improved type is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-118.
No. 171, the three actuators 4, 5 and 6 are connected to the base 1 as shown in FIG.
, And each actuator 4, 5,
The fulcrums 7, 8, and 9 for moving the table 3 by the feed screw units 10, 11, and 12 are structured to slide freely on the side surfaces of the table. Although not shown in FIG. 1, there is an elastic pressing portion abutting the table side on the side opposite to the actuators 4, 5 and 6 with the table 3 interposed therebetween. Is in contact with the side surface of the table 3.

In such an improved XYθ stage, when the table 3 is moved in the Y direction, as shown in FIG. 2, when the table 3 is not tilted, the corresponding actuator 6 may be moved by the moving amount. But,
As shown in FIG. 3, when the table 3 is tilted by an angle θ with respect to the X direction, when the actuator 6 in the Y direction is moved by a moving amount ΔY, as shown in FIG. Along the fulcrum 8 in a direction inclined by an angle θ with respect to the Y direction by a movement amount ΔY · cos θ.
This is because the amount of movement in the X direction− (ΔY · cos θ) sin
In the θ and Y directions, it has been moved by the movement amount (ΔY · cos θ) cos θ.

Therefore, when the table 3 is tilted,
In order to move the actuator only in the direction, it is necessary to move not only the actuator 6 corresponding to the Y direction but also the actuators 4 and 5 in the X direction. The amount of movement in the Y direction is Δ
The driving amount of each of the actuators 4, 5, and 6 in the case of Y is as follows, assuming that the actuator is not moved in the X direction.

Actuator 4: ΔY · tan θ Actuator 5: ΔY · tan θ Actuator 6: ΔY

When the table 3 is to be moved in the X direction, if the table 3 is not tilted, the table 3 is moved in the X direction.
It is sufficient to move the two actuators 4 and 5 by the same movement amount ΔX. However, as shown in FIG. 5, when the table 3 is inclined by the angle θ with respect to the X direction, for example, the actuators 4 and 5 are moved by the movement amount ΔX. , The table 3 moves along the fulcrum 9 in a direction inclined by an angle θ with respect to the X direction
Move by X · cos θ. This is (ΔX
Cos θ) cos θ, (ΔX cos θ) in the Y direction
sin θ has been moved.

Therefore, if the table 3 is to be moved only in the X direction in a tilted state, it is necessary to move not only the actuators 4 and 5 but also the actuator 6.
Assuming that the amount of movement in the X direction is ΔX, the amount of movement of each of the actuators 4, 5, and 6 is as follows, assuming that they do not move in the Y direction.

Actuator 4: ΔX Actuator 5: ΔX Actuator 6: -ΔX · tanθ

As described above, in the improved type, all of the three actuators 4, 5, and 6 can be moved in either the X direction or the Y direction while the table 3 is inclined. Need to be driven.

Generally, when the actuator 6 in the Y direction is moved by a moving amount ΔY and the actuators 4 and 5 in the X direction are moved by a moving amount ΔX from the state shown in FIG. The following equations hold as ΔX ′ and ΔY ′.

[0013]

(Equation 1)

By solving this, the following equation is obtained.

[0015]

(Equation 2)

The amount of movement Δ of the table 3 in the X direction
When the movement amount ΔY is to be moved in the X and Y directions, the movement amounts of the actuators 4, 5, and 6 are as follows.

Actuator 4: ΔX + ΔY · tan θ Actuator 5: ΔX + ΔY · tan θ Actuator 6: −ΔX · tan θ + ΔY

[0018]

2. Description of the Related Art Considering a case where pulse actuators are used as actuators 4, 5, and 6 and driven by a feed screw unit (ball screw / nut), this drive system has a pitch error and a backlash. Since a rush occurs, the more the number of axes to be moved, the worse the overall position accuracy becomes. In this XYθ stage, the table 3 is inclined rather than a general usage. In such a case, even if it is desired to simply move in one of the X direction and the Y direction, three actuators 4 are required. 5 and 6 must be moved simultaneously, which is disadvantageous in terms of accuracy.

When moving in the X direction and the Y direction, an operation using the coefficient tanθ in the above equation is required. The value of the coefficient tanθ is determined by the inclination of the table in the X direction, that is, two actuators. The difference between the positions in the Y direction at 4 and 5 and the difference between the positions in the X direction at the two fulcrums 7 and 8 can be obtained. In consideration of the above pitch error and backlash, the accuracy increases as the calculation amount increases. Be disadvantaged.

[0020]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a three-dimensional moving device which is mounted on a water smooth running portion of a base and is movable in X, Y, and θ directions.
In the XYθ stage having actuators,
Movement in one direction in X direction or Y direction and XY
To improve the stage positioning accuracy of the movement in the two directions.

[0021]

To achieve the above object, the present invention (claim 1) provides a base provided with a water smooth running portion, which is mounted on the water smooth running portion of the base and is movable in X, Y, and θ directions. In an XYθ stage having a table, three actuators for driving the table in the X, Y, and θ directions, and a feed screw unit for transmitting a drive amount of each actuator to the table, the actuator is fixed on an X base. The three fulcrums that can move on the guides in the direction and the Y direction, and follow the guides in accordance with the driving of other actuators, and that connect the feed screw unit of each actuator and the table, They are in place on the table.

In another aspect of the present invention (claim 4), the X
In the Yθ stage, data input means for inputting a table movement amount and rotation center coordinate data, fulcrum information storage means for storing and updating position data of each fulcrum every time the table is moved, and moving and rotating the table An axis movement amount calculating means for calculating the axis movement amount of each actuator from the data of the central coordinates and the position data of each fulcrum, and a control means for driving each actuator based on the axis movement amount calculating means, to control the control device. Make up.

[0023]

FIG. 6 shows an XYθ stage of the present invention. As in the case of the conventional example, the base 1 is, for example, rectangular and has a water smooth running portion 2 on the upper surface. The rectangular table 3 is placed on the water running section 2 and is movable in the X, Y, and θ directions. It should be noted that the water leveling unit 2 moves the table 3 to move the table 3 as shown in FIG.
As shown in FIG. 1, the base 1 is composed of a large number of small hard spheres 2a rotatable on the base 1.

The table 3 has three actuators 4,
5 and 6 are driven. That is,
One actuator 6 is provided on the base 1 in the Y direction to drive the table 3 in the Y direction, and is connected to the table 3 by a feed screw unit 12 and a fulcrum 9. The two actuators 4 and 5 are provided on the base 1 in the X direction in order to drive the table 3 in the X direction. The feed screw units 10 and 11 and the fulcrums 7 and 8 are used to move the edge of the base 3. Connected to the department. These fulcrums 7, 8, and 9 are vertical pins, and are rotatable with respect to the respective ends of the feed screw units 10, 11, and 12 and are fixed at fixed positions on the table 3.

The actuator 6 is movable on the base 1 in the X direction by a guide 15 parallel to the X direction, and is driven along the guide 15 as the other actuators 4 and 5 are driven. You can move to. The other actuator 4 is movable along a Y-direction guide 13 fixed on the base 1,
As the other actuators 5 and 6 are driven, the actuator is driven and moved along the guide 13. The other actuator 5 is movable along a Y-direction guide 14 fixed on the base 1, and is driven along the guide 14 by driving the other actuators 4 and 6. It is designed to move.

In such an XYθ stage, since there are no guide rails, θ-axis turning bearings, etc. as guides for each axis, the observation window 1
6 can be provided. The observation window 16 is used as an opening for observing a workpiece inside the observation window 16 by a camera from above, or as an opening for introducing a light beam such as a lighting device arranged below the observation window 16. You.

In the XYθ stage of the present invention, when the table 3 is moved in the Y direction, as shown in FIG. 8, when the table 3 is not tilted, the actuator 6 may be moved in the Y direction by the moving amount ΔY. This way,
The actuators 4, 5 are moved along guides 13, 14,
It slides in the Y direction by the same movement amount ΔY.

When the table 3 is moved in the X direction,
As shown in FIG. 9, when the table 3 is not tilted, the actuators 4, 5 may be moved in the X direction by the movement amount ΔX. In this case, the actuator 6 slides along the guide 15 for guidance by the same movement amount ΔX in the X direction.

Next, as shown in FIG. 10, consider a state in which the table 3 is tilted counterclockwise by an angle θ with respect to the X direction. When only the actuator 6 is driven from the state where the table 3 is rotated by the angle θ with respect to the X direction as shown in FIG. 11, the other actuators 4 and 5 are moved along the guides 13 and 14 for guiding. Since the table 3 slides in the direction, the table 3 can move only in the Y direction.

When the actuators 4 and 5 are driven by the same amount of movement as shown in FIG. 12 from the state where the table 3 is rotated by the angle θ with respect to the X direction, the other actuators 6 are driven by the guides 15 for guiding. , The table 3 can move only in the X direction.

Although not shown, even when the table 3 is moved in the X and Y directions after being rotated by the angle θ with respect to the X direction, the actuators 4 and 5 are moved by the amount of movement in the X direction, and the actuator 6 is moved in the X direction. , In the Y direction. Here, the calculation using the coefficient tanθ is unnecessary.

When the table 3 is moved by the movement amount ΔX in the X direction and by the movement amount ΔY in the Y direction, the movement amounts of the actuators 4, 5, and 6 are as follows.

Actuator 4: ΔX Actuator 5: ΔX Actuator 6: ΔY

Thus, according to the present invention, the table 3
When moving in the X or Y direction from a tilted state,
It is not necessary to move all three axes, and even when moving in both the X direction and the Y direction, the calculation of the coefficient tanθ becomes unnecessary, so that the overall position accuracy is improved as compared with the conventional one.

The actuators 4, 5, and 6
If an AC servomotor is used to form a semi-closed loop, accurate positioning control can be performed. In addition, place a glass plate for work setting on the observation window 16,
By illuminating the television camera from above the table 3 and illuminating the glass plate of the observation window 16 from below the table, positioning using image processing by transmitted illumination is also possible.

Next, FIG. 13 shows a control device of the XYθ stage of the present invention. The data input means 20 is provided on the XYθ stage of the present invention for inputting the movement amounts ΔX, ΔY, Δθ to move the table 3 and the coordinates Pc (Xc, Yc) of the rotation center of θ rotation. ing. These movement amounts ΔX, ΔY, and Δθ are relative movement amounts from the current position or, as illustrated in FIG. 14, in a machine coordinate system having a reference point defined on the base 1 as a machine origin. It is given as an absolute displacement.
The data input means 20 includes a method in which an operator directly inputs from an input device such as a keyboard and a touch panel, an automatic input method in which reference is made sequentially according to data of an internal program such as a predetermined NC program,
There is a method of inputting from a control device such as a computer installed outside using means such as communication.

The fulcrum information storage means 19 stores the distances A, B, and C between the fulcrums 7, 8, and 9 and the coordinates P1 (U, Uy), P2 (P2) of the fulcrums 7, 8, and 9 in the machine coordinate system. V, V
y), among P3 (Wx, W), coordinate values U, V, W are stored as positions from the origin in each control axis direction, and the axis control means 18 completes the axis movement for moving or rotating the table 3. A memory that updates these coordinate values U, V, and W at the timing, for example, a memory such as a floppy disk, a hard disk, or a RAM. The amount of drive of each of the actuators 4, 5, and 6 in the direction of each control axis is determined by the amount of movement ΔU, ΔV of the corresponding fulcrum 7, 8, 9 in the direction of each control axis.
It is equal to ΔW.

The coordinate values U, V, and W as the current positions of the respective fulcrums 7, 8, and 9 in the respective control axis directions are temporarily stored in the fulcrum information storage means 19 at the time of the axis movement calculation. It is updated by being replaced with the coordinate values after the movement after waiting for the completion of the axis movement from the means 18.

The axis movement amount calculation means 17 calculates the movement amount ΔU of each axis from the data from the data input means 20 and the data from the fulcrum information storage means 19 based on the following coordinate conversion formula. ΔV and ΔW are obtained. For example, if the actuators 4, 5, and 6 are pulse motors, the axis control means 18 is composed of a pulse generator and a motor drive driver, and calculates the movement pulse amount for each axis given from the axis movement amount calculation means 17. Commands are given to each of the actuators 4, 5, and 6.

As shown in FIG. 14, the coordinates of the fulcrums 7, 8, and 9 in the machine coordinate system are defined as follows.

Support 7: P1 (U, Uy) Support 8: P2 (V, Vy) Support 9: P3 (Wx, W) Distance between supports: A, B, C Any point Pc (Xc, Xc, Yc) Inclination of table 3: φ Angles of vertices of triangles at fulcrums 7, 8, 9: θ1, θ2,
θ3

The coordinates Pc (X) of an arbitrary point on the table 3
c, Yc), the amount of movement ΔU, ΔV, ΔW of each of the fulcrums 7, 8, 9 when the table 3 is moved to the point P′c (X′c, Y′c) while rotating the table 3 by Δθ. Ask. Here, φ ′ = φ + Δθ. These movement amounts Δ
U and ΔV correspond to the drive amounts of the actuators 4 and 5, respectively, and the movement amount ΔW corresponds to the drive amount of the actuator 6.

The coordinates P1 (U, Uy), P2 (V, Vy), P2 of the fulcrum 7, 8, 9 at the current position in the machine coordinate system.
3 (Wx, W), the inner coordinate values U, V, W are known,
The fulcrum information storage means 19 holds the information. The fulcrum distances A, B, and C are also known and are held by the fulcrum information storage means 19.

The following equation is derived geometrically from FIG. Note that when φ = 0, U = V.

[0045]

(Equation 3)

Here, the obtained movement amounts ΔU, ΔV, ΔW
Is the drive amount of each of the actuators 4, 5, and 6, as described above. Here, the table 3 is moved in the X and Y directions by an amount Δ
Assuming that it is moved by X and ΔY and that there is no rotation, assuming that Δθ = 0 in the above equation, the respective movement amounts are as follows.

The amount of movement of the actuator 4 ΔU = ΔX The amount of movement of the actuator 5 ΔV = ΔX The amount of movement of the actuator 6 ΔW = ΔY

[0048]

According to the present invention, when the table is moved in the X direction or the Y direction from the inclined state, it is not necessary to move all the actuators in the three directions, and even when the table is simultaneously moved in both the X direction and the Y direction. Since the calculation of the coefficients is unnecessary, the overall positioning accuracy of the table is improved. Further, since the calculation of the coefficient is unnecessary, the response speed of the control system is increased.

[Brief description of the drawings]

FIG. 1 is a plan view of a conventional improved XYθ stage.

FIG. 2 is a plan view of a conventional improved XYθ stage when a table is moved in a Y direction.

FIG. 3 is a plan view showing a state in which a table is tilted in a conventional improved XYθ stage.

FIG. 4 is a plan view when a tilted table is moved in a Y direction on a conventional improved XYθ stage.

FIG. 5 is a plan view when a tilted table is moved in an X direction on a conventional improved XYθ stage.

FIG. 6 is a plan view of the XYθ stage of the present invention.

FIG. 7 is an enlarged sectional view of a water smooth running portion of the XYθ stage of the present invention.

FIG. 8 is a plan view when the table is moved in the Y direction on the XYθ stage of the present invention.

FIG. 9 is a plan view showing a state in which the table is moved in the X direction on the XYθ stage of the present invention.

FIG. 10 is a plan view of the XYθ stage according to the present invention in a state in which the table is rotated counterclockwise by θ.

FIG. 11 is a plan view of the XYθ stage of the present invention when the table is moved in the Y direction from a state where the table is rotated θ.

FIG. 12 is a plan view of the XYθ stage of the present invention when the table is moved in the X direction from a state where the table is rotated θ.

FIG. 13 is a block diagram of an XYθ stage control device of the present invention.

FIG. 14 is an explanatory diagram of coordinate calculation of a table.

[Explanation of symbols]

 Reference Signs List 1 base 2 water smooth running section 2a hard sphere 3 table 4 actuator 5 actuator 6 actuator 7 fulcrum 8 fulcrum 9 fulcrum 10 feed screw unit 11 feed screw unit 12 feed screw unit 13 guide 14 guide 15 guide 16 observation window 17 axis moving amount calculating means 18 Axis control means 19 Support point information storage means 20 Data input means

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Shuya Yamada, Inventor, 662 Nojiri, Fukuno-cho, Higashi Tonami-gun, Toyama Prefecture Inside Rosef Technology Co., Ltd. 1 Inside Rosef Technology Co., Ltd. (72) Inventor Akira Ooka 662 Nojiri, Fukuno-cho, Higashi Tonami-gun, Toyama Prefecture 1 Inside Rosef Technology Co., Ltd.

Claims (4)

[Claims] 1. A base having a water smooth running section, a table mounted on the water smooth running section of the base and movable in X, Y, and θ directions, and driving the table in X, Y, and θ directions.
XYθ having a number of actuators and a feed screw unit for transmitting the drive amount of each actuator to the table
In the stage, the actuator is movable on guides in the X direction and the Y direction fixed on the base, and moves along the guides in accordance with the driving of other actuators. An XYθ stage, wherein three fulcrums connecting the screw unit and the table are at fixed positions on the table. 2. The XYθ stage according to claim 1, wherein the water smooth running portion is constituted by a plurality of small hard spheres rotatable. 3. The XYθ stage according to claim 1, wherein an observation window is provided at a center of the table. 4. A base provided with a water smooth running section, a table mounted on the water smooth running section of the base and movable in X, Y, and θ directions, and driving the table in X, Y, and θ directions.
XYθ having a number of actuators and a feed screw unit for transmitting the drive amount of each actuator to the table
In the stage, the actuator is movable on guides in the X direction and the Y direction fixed on the base, and moves along the guides in accordance with the driving of other actuators. The three fulcrums that connect the screw unit and the table are, on the XYθ stage at a fixed position on the table, the movement amounts ΔX, ΔY, Δθ of the table and the coordinates Pc (Xc, Xc,
Yc) data input means, fulcrum information storage means for storing and updating the position data of each fulcrum every time the table is moved, data on the amount of movement of the table and the coordinates of the center of rotation and the position of each fulcrum A control device for an XYθ stage, comprising: axis movement amount calculation means for calculating the axis movement amount of each actuator from data; and control means for driving each actuator based on the axis movement amount calculation means.