JP2000235417A - Positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive positioning device for realizing 1 nm highly precise positioning. SOLUTION: This positioning device is provided with a rough adjusting means for rough adjusting a table to an X direction to a base, a fine adjusting means for fine adjusting the table to the X direction by using the expansion of a piezoactuator after the rough adjustment, and a displacement detecting means 80. This displacement detecting means 80 is provided with a detector 83 including a main scale, index scale, and light emitter/receiver for outputting two analog detection signals Ax and Bx position shifting at 90 deg. and an N1 multiplying circuit 90 including plural multipliers 91 and 96 or the like for N1 multiplying one cycle pitch P of the two analog detection signals Ax and Bx inputted from the detector in synchronizing states, and an N2 dividing circuit for generating a digital detection signal whose resolution is 1 nm obtained by N2 dividing one cycle pitch of each analog detection signal after the multiplication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base including a base and a table mounted so as to be relatively movable in an axial direction, a feed screw shaft mounted on the base, and a nut member mounted on the table. Coarse movement adjusting means for coarsely adjusting the table in the axial direction, fine adjustment means for finely adjusting the table relative to the base relative to the base by using expansion and contraction of the piezo actuator after the coarse adjustment, and at least fine adjustment The present invention relates to a positioning device provided with a displacement detection means for detecting a table displacement for a feedback signal at the time of fine movement adjustment of the means.

[0002]

2. Description of the Related Art Positioning devices capable of positioning with an accuracy of 10 nm have been proposed (for example, Japanese Patent Application Laid-Open Nos. 9-192965 and 10-58267). As shown in FIG. 15, these positioning devices include a base 10 and a table 20 which are mounted to be relatively movable in the direction of the axis (X) via cross roller bearings 18 and 28.
And a feed screw shaft 3 rotatably mounted on the base 10 side
Coarse adjustment means 30 for coarsely adjusting the table 20 in the X direction with respect to the base 10 using the rotation of the feed screw shaft 33, including the nut 3 and the nut member 34 attached to the table 20 side.
And fine movement adjusting means 40 for finely adjusting the table 20 in the X direction with respect to the base 10 by using expansion and contraction of the piezo actuator 41 after the coarse movement adjustment, and a feedback signal at least for fine movement adjustment of the fine movement adjustment means 40 And a displacement detecting means (80) for detecting a table moving displacement for use. The table 20 is pulled by a tension spring 65 toward the motor (31) forming a part of the coarse movement adjusting means 30.

In order to set the positioning accuracy to 10 nm and achieve high-speed positioning, a feed pitch of a feed screw shaft 33 and a coarse movement adjusting means 30 including a stepping motor 31 serving as the above-mentioned motor are added to the motor 31 by one pulse. The table 20 per signal is, for example, 100 nm X
In the in-position range (for example, ± 100 n) around the target position shown in FIG.
The open control shown in FIG.

Next, feedback control shown in FIG. 1C is performed on the stepping motor 31 so as to fall within the in-position range. The feedback signal is a digital detection signal at the position of the table 20 at that time detected by the displacement detection means (80), that is, a signal corresponding to a movement displacement.

The displacement detection means (80)
0 (or the base 10) attached to the main scale 81 (scale surface 81F) shown in FIG.
(Or table 20), two analog detection signals Ax including a detection head 82 including an index scale and a light emitting and receiving device and a detection circuit (not shown) and having a phase shift of 90 degrees shown in FIG. , Bx, and a 400-divided circuit (100P) that generates a digital detection signal having a 40-nm one-cycle pitch obtained by dividing the one-cycle pitch of the two analog detection signals Ax, Bx shown in FIG. ), And is formed from.

If the scale pitch, which is the optical grating of the main scale 81, is 8 μm (bright line width 4 μm), a digital detection signal having a resolution of 10 nm is obtained from a digital detection signal having a cycle pitch of 40 nm shown in FIG. A detection signal (feedback signal) can be easily generated. Thus, if this is used for the feedback signal, the control shown in FIG. 16C can be performed simply and quickly.
However, since the coarse motion adjustment by the coarse motion adjusting means 30 including the stepping motor 31, the feed screw shaft 33, and the like is performed at, for example, 100 nm per pulse, the coarse motion is adjusted within ± 100 nm (in-position range) shown in FIG. Even if it can be inserted, it cannot be moved to the target position (± 10 nm).

Therefore, feedback control shown in FIG. 16D is performed on the fine movement adjusting means 40, that is, the piezo actuator 41. For example, by driving the piezo actuator 41 having a drive voltage of 100 mV per 10 nm of expansion / contraction amount to adjust the amount of expansion / contraction to the feed screw shaft 33 forming the coarse movement adjusting means 30, as a result, predetermined positioning at the target position is achieved. Positioning can be performed with accuracy (± 10 nm).

Thus, precision electronic parts / optical parts, IC
The spread of use for substrate inspection and data analysis / verification is remarkable.

[0009]

By the way, there is a strong demand for further improvement of positioning accuracy, but a positioning device which satisfies versatility including cost conditions and is capable of stable operation has not yet been established. Applicants analyze that the following multiple events are caused by the complexity and mutual influence.

That is, when the positioning accuracy of the proposed positioning device is set to 1 nm, the detection accuracy (resolution) of the displacement detecting means 80 for generating a feedback signal may be improved from 10 nm to 1 nm. Theoretically, the scale pitch of the main scale 81 is set to 8 μm to, for example, 3.2 μm or 1.6 μm.
And the analog detection signal from the detector may be divided from 400 to 3200 or 1600.

However, 1.6 μm (bright line width 0.8 μm)
In the case of (1), it is the minimum limit that can be manufactured at present, and it is necessary to perform individual and direct drawing using an electron beam drawing apparatus, so that the cost of the main scale 81 and the like is greatly increased. In this respect, at 3.2 μm (bright line width: 1.6 μm), it is possible to transfer and duplicate the image after drawing an electron beam, which is advantageous in terms of scale production in terms of cost.

Considering the machining and assembly, the gap required to obtain the maximum output voltage (or current) of the analog detection signals Ax and Bx from the detector as "100", that is, FIG. The gap between the main scale 81 and the detection head 82 which forms a part of the detector including the index scale shown in FIG.
m ± 0.3 mm and the center shift must be 0.5 mm or less. If this is assumed and the output voltage is allowed to drop to a practically usable "70", each of the scale pitches 8 μm, 3.2 μm and 1.
The tolerance range of each mounting angle for every 6 μm must be suppressed to the value shown in FIG.

According to this, the scale pitch is 1.6 μm
The moire angle shown in FIG.
The roll angle in (C) is 2.0 minutes, and the pitch angle in (D) is 1.2 minutes. Observing within each angle is
Considering the processing time of each part, finishing accuracy, man-hours for assembling, mounting and fixing work, etc., it is almost impossible to realize.

From this point, when it is 3.2 μm, the moiré angle is 1.0 minute, the roll angle is 4.0 minutes, and the pitch angle is 2.4 minutes. It can be said that each of these values is a feasible limit in realization.

In consideration of the above specific circumstances, the scale pitch is set to be 3.2 μm and the analog detection signals Ax and B are compared with the case where the scale pitch is set to 1.6 μm and divided by 1600.
It is considered better to divide x into 3,200. But,
There is a practical problem in that the market distribution quantity of the positioning accuracy of 1 nm and 10 nm must be considered.

That is, since a positioning accuracy of 10 nm is often used sufficiently, a 3200 division circuit (100P) for 1 nm which is considered to have a relatively small quantity is considered.
Is compared to the 400-divided circuit 100P for 10 nm,
The reality is that the cost is significantly increased. In other words, from the viewpoint of spread, the 3200-divided circuit can be said to be ineligible.

Further, in actual operation, there is a possibility that the positioning speed is reduced in order to achieve a positioning accuracy of 1 nm. That is, in the case where the feed error per stroke of the coarse motion adjusting means 30, especially the screw shaft structure (33, 34) is fixed, the positioning accuracy is 10 nm to 1 n.
m, the stepping motor 3 shown in FIG.
In the feedback control of 1 to the feedback control of the piezo actuator 41 of FIG. 16D, there is a possibility that the number of executions of the left and right repetitions in the figure centering on the target position increases.

Further, the piezo actuator 41 forming the fine movement adjusting means 40 has a total extension (reduction) amount [for example, 7.5.
μm or 15 μm].
Since it is as high as V, it is very difficult to reduce the ripple and spike of the power supply device. That is, when the above-described piezo actuator 41 is employed, the driving voltage per 1 nm becomes 10 mV or less, so that there is a concern about the influence of noise. On the other hand, if the cost condition is satisfied and the positioning accuracy of 1 nm can be established, the plane (X
It has been pointed out and requested that the method is applied to not only the Z-axis but also the Z-axis, that is, it is extremely useful for three-dimensional positioning.

An object of the present invention is to provide a low-cost positioning device capable of performing high-precision positioning of 1 nm.

[0020]

According to a first aspect of the present invention, there is provided a base and a table mounted so as to be relatively movable in an axial direction, a feed screw shaft mounted on the base side, and a nut member mounted on the table side. Coarse adjustment means for coarsely adjusting the table relative to the base in the axial direction, and fine adjustment means for finely adjusting the table relative to the base in the axial direction using expansion and contraction of the piezo actuator after the coarse adjustment is completed. And a displacement detection means for detecting at least a table displacement for a feedback signal at the time of fine movement adjustment of the fine movement adjustment means, wherein the displacement detection means is attached to one of the base and the table. Two analog detectors that are out of phase, including the main scale and the index scale and photodetector mounted on the other side A detector capable of outputting a signal, an N1 multiplier including at least two multipliers and N1 multiplying one cycle pitch of two analog detection signals input from the detector in a synchronized state, and an input from the N1 multiplier. 1 cycle pitch of each analog detection signal after multiplication by N
And a N2 dividing circuit for generating a digital detection signal divided into two.

In this invention, when the motor forming the coarse adjustment means is driven to rotate the feed screw shaft, the nut member forming, for example, a ball screw structure moves together with the feed screw shaft in the axial direction. That is, the table can be moved (coarse movement adjustment) in the axial direction. For example, 100n
The coarse adjustment is performed by open control with a resolution of m, and the position is set within the in-position range (for example, ± 10 nm). This coarse movement adjustment is performed in accordance with the conventional example shown in FIGS. 16B and 16C.
Either step control or one-step feedback control (C) alone may be used.

After the coarse movement adjustment is completed, the piezo actuator forming the fine movement adjustment means is extended or contracted based on the relationship between the final positioning point and the coarse movement adjustment amount. In other words, if the piezo actuator is expanded and contracted,
The table can be finely adjusted with respect to the base as in the case of the coarse adjustment.

Here, for example, the main scale on the table side and the detector including the index scale and the light receiving / receiving device on the base side which form the displacement detecting means move relatively in the axial direction, so that the phase shift (for example, 90 degrees)
The two analog detection signals are output. An N1 multiplier circuit including at least two multipliers multiplies one cycle pitch of two analog detection signals input from the detector by N1 in a synchronized state. That is, the frequency of each analog detection signal output from the detector is increased by N1 times.

Thus, the N2 dividing circuit generates and outputs a digital detection signal obtained by dividing the one cycle pitch of each N1 multiplied analog detection signal input from the N1 multiplying circuit by N2. The number of divisions of this N2 division circuit is the
2 = 400). That is, this multiplication process (also called synchronous detection or phase detection).
Can be easily executed by an analog multiplier and is very inexpensive as compared with, for example, 3200 division processing by a high division circuit.

Therefore, since it is easy to generate and output a 1-nm feedback signal (digital detection signal) using each digital detection signal divided by the displacement detecting means, the piezo actuator can be controlled using this as a feedback signal. For example, the table can be positioned with high accuracy with a resolution of 1 nm with respect to the base.

According to a second aspect of the present invention, the scale pitch of the main scale is 3.2 μm, and one cycle pitch of each analog detection signal output from the detector is optically divided into two. 6 μm and 90 ° out of phase with each other. The multiplication integer N1 of the N1 multiplication circuit is 4 and the division integer N2 of the N2 division circuit is 40.
The positioning device is set to 0.

In this invention, the two analog detection signals output from the detector and shifted in phase by 90 degrees are:
It is optically divided into two and each cycle pitch is 1/2 of the scale pitch of 3.2 μm, that is, 1.6 μm. Therefore, the multiplication integer N1 is 4 in the N1 multiplication circuit of 4.
If the multiplication process is performed, the one cycle pitch of the two analog detection signals after the multiplication process becomes 400 nm. If these are divided by an N2 division circuit having a division integer N2 of 400, digital detection for a feedback signal having a resolution of 1 nm is performed. A signal can be generated.

Here, if the scale pitch of the main scale is, for example, 3.2 nm, there is no problem in the production of electron beam lithography and the transfer duplication is easy as compared with the case of 1.6 nm. In addition, the N1 multiplier circuit may be, for example, 1 (2) -stage arithmetic processing using 2 (4) multipliers, and the N2 dividing circuit may be a conventional one (400).
A dividing circuit similar to (dividing) may be used. Moreover, assembling to the base and the table and gap adjustment can be performed relatively easily and reliably.

Therefore, in addition to providing the same operation and effect as the case of the first aspect of the present invention, it is possible to further manufacture and
Stable positioning operation can be performed while further reducing costs by facilitating assembly.

Further, the invention according to claim 3 is characterized in that the N1 multiplier circuit includes a first multiplier for multiplying the one analog detection signal Ax and the other analog detection signal Bx output from the detector, A first sum-difference calculator for calculating a difference (Ax−Bx) between the signal Ax and the other analog detection signal Bx, and a difference [Bx − (−) between the other analog detection signal Bx and the inverted value of the one analog detection signal Ax. Ax)], a second sum-difference calculator for calculating the difference (Ax−Bx) and the difference [B
x − (− Ax)], and a second multiplier for multiplying
A first doubling circuit capable of generating and outputting each analog detection signal having a frequency which is twice the frequency of the analog detection signal Ax and the other analog detection signal Bx, and a second doubling circuit having the same structure as the first doubling circuit. It is a positioning device.

In this invention, the first 2
In the multiplication circuit, the first multiplier outputs one analog detection signal Ax and the other analog detection signal Bx output from the detector.
And are multiplied as they are. The second multiplier calculates a difference (Ax−Bx) between the one analog detection signal Ax and the other analog detection signal Bx calculated by the first sum difference calculator, and
The difference [Bx − (−) between the other analog detection signal Bx calculated by the sum-difference calculator and the inverted value of the one analog detection signal Ax.
Ax)]. The first and second multipliers include one analog detection signal Ax and the other analog detection signal Bx.
Each analog detection signal having a frequency that is twice the frequency of x is generated and output.

The two analog detection signals subjected to the doubling process are input to a second doubling circuit, and a doubling process similar to that of the first doubling circuit having the same structure is performed. Thus, by using the two analog detection signals output from the N1 multiplier circuit, a digital detection signal having a resolution of 1 nm can be easily generated.

Therefore, in addition to providing the same operation and effect as in each of the first and second aspects of the present invention, the first and second sum-and-difference calculators are commercially available operational amplifiers, Since the second multiplier can be constructed with a commercially available analog multiplier, the cost can be further reduced and the reliability is improved.

Further, according to a fourth aspect of the present invention, the driving voltage per 1 nm of expansion and contraction of the piezo actuator is 20 m.
The positioning device is set to V or higher.

In this invention, for example, the conventional piezo actuator has a full expansion / contraction amount of 15 μm and a driving voltage of 15 μm.
Since the driving voltage per 10 nm is 10 mV since it is 0 V, in the case of the present invention where the positioning accuracy is 1 nm, the in-position range at the time of the feedback control of the stepping motor can be narrowed. Further, the full expansion / contraction amount is set to, for example, 150 V and 7.5 μm, and the driving voltage per 1 nm of the expansion / contraction amount can be selected to be 20 mV or more.

Therefore, in addition to the effects similar to those of the first to third aspects of the present invention, the ripples and the like of the power supply device for the piezo actuator are the same as those of the prior art. Even if 1
The influence of noise on the nm feedback control can be reduced or eliminated.

Further, according to the present invention, the axial error data of the feed screw shaft and the nut member can be stored, and the stepping motor forming the motor connected to the feed screw shaft is rotated. The positioning device is configured to be capable of performing the coarse adjustment as a corrected target position obtained by correcting a target position with error data corresponding to the target position when driving.

In this invention, the feed characteristic (or error) of the ball screw structure and the number of pulse signals for driving the stepping motor are made to correspond to each other with respect to the full stroke in the axial direction of the feed screw shaft and the nut member, for example, the ball screw structure. The error data is stored manually or automatically. Then, when the stepping motor is rotationally driven, the coarse movement adjustment is performed by setting the target position as a corrected target position (the number of pulse signals) corrected by error data corresponding to the target position.

Therefore, in addition to providing the same functions and effects as in each of the first to fourth aspects of the present invention, the two-stage control shown in FIGS. 16B and 16C of the conventional example is required. Can be changed to only one-step control corresponding to (C), so that the positioning speed at a resolution of 1 nm can be increased.

Further, according to a sixth aspect of the present invention, in the positioning apparatus, the nut member is connected to the table in the axial direction so as not to be relatively displaceable by using a position regulating surface and a leaf spring on a lower surface of the table. It is.

According to this invention, the nut member is pressed against the position regulating surface on the other side by the leaf spring on one side of the lower surface of the table, and is connected to the table in the axial direction so as not to be relatively displaceable. In addition to providing the same functions and effects as in each of the inventions up to the fifth aspect, positioning can be performed with a high accuracy of 1 nm even in a usage method in which the axis is perpendicular. Therefore, three-dimensional positioning can be performed by combining three units.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 10, the positioning device includes a base 10 and a table 20 mounted to be relatively movable in an axis (X) direction, a feed screw shaft 33 on the base side, and a nut member 34 on the table side. Coarse movement adjusting means 30 for coarsely adjusting the movable table 20 in the X direction
And fine movement adjusting means 40 for finely adjusting the table 20 in the X direction with respect to the base 10 by using expansion and contraction of the piezo actuator 41 after the coarse movement adjustment, and a feedback signal for fine movement adjustment of the fine movement adjustment means. A displacement detecting means 80 for detecting the amount of table movement displacement is provided. The displacement detecting means 80 further includes a main scale 81, an index scale 84, a light emitting device (not shown), and a light receiving device (82A in FIG. 10). (Detection head 82, detection circuit 83) that can output two analog detection signals Ax and Bx that are out of phase by two degrees, and two detectors (83) that include a plurality of multipliers 91 and 96 and that are input from the detector (83). One cycle pitch of the analog detection signals Ax and Bx is synchronized with N1
(= 4) N1 multiplying circuit 90 for multiplying, and one cycle pitch of each analog detection signal after multiplying by 4 is set to N2 (= 400)
N to generate a divided digital detection signal with a resolution of 1 nm
It is formed from the two-divided circuit 100 and is formed so as to be positionable with an accuracy of 1 nm.

In FIG. 1 to FIG.
The table 20 and the table 20 can be relatively displaced in the X direction via cross roller guides (base side cross roller bearings 18, 18 and table side cross roller bearings 28, 28). In FIG. 6, a housing space SP is formed between the two 10 and 20 in the vertical direction.
In this embodiment, it is used for positioning for switching switching of an optical fiber cable (sample).

The base 10 is provided with a hollow portion 15 and a penetrating portion 16 shown in FIG. 6, and a base end (right side) is provided with a bracket 32 for attaching a stepping motor 31. Also, on the upper surface side of the table 20, FIG.
Are provided with a plurality of mounting screw holes 29 for mounting a sample (not shown).

Here, the coarse movement adjusting means 30 is shown in FIGS.
, A feed screw shaft (ball screw shaft) 33 connected to a motor shaft 31S via a coupling 35, and a nut screwed to the feed screw shaft 33 and connected to the lower surface of the table 20. And a member 34. 31T is a knob for manual operation.

More specifically, the nut member 34 is connected to the table 20 in the X direction using a position regulating surface 20F on the lower surface of the table and a leaf spring 21 as shown in FIG. This is because even in a usage method in which the axis X is perpendicular, positioning can be performed with high accuracy of 1 nm as in the case of the plane (X axis, Y axis). Therefore, this device 3
If the tables are combined, high-precision three-dimensional positioning of 1 nm can be performed.

The piezo actuator 41 which constitutes a part of the fine movement adjusting means 40 has a structure as shown in FIGS.
The base end (left side) is fixed to the base 10 via the backup block 47 and the holding screw 48 in the accommodation space SP. That is, relative displacement with the base 10 in the X direction is not possible. Therefore, the tip (right side)
It can expand and contract in the X direction.

The piezo actuator 41 in this embodiment is a laminated piezoelectric actuator element [NEC (A
E0505D08)] and a voltage (0 to 150
V), a displacement (0 to 7.5 μm) can be obtained. In other words, the drive voltage per 1 nm elongation (shrinkage) amount is 20 m
V is selected so as to be hardly affected by external noise. The power supply device (150 V) is the same as that of the conventional piezo actuator (150 V-15 μm) (FIG. 15).

A voltage of 75 V is constantly applied using a piezo driver (not shown), and ± 3.7 in the X direction with the coarse movement adjustment end position of the table 20 as the center (reference).
The table 20 is formed so as to be finely adjustable within 5 μm.

The piezo actuator cable C
p is pulled out from the base 10 side as shown in FIGS. The same applies to the displacement detection cable Ch. Cm in FIG. 13 is a cable for a motor, a limit switch, and the like, and is connected via a connector 39.

A stepped shaft 42 shown in FIG. 6 is fixed to the tip (right side) of the piezo actuator 41, and a miniature bearing 46 is fitted to the shaft 42 so as not to be displaceable in the left-right direction. ing. However, screw shaft 3
The external force from the third side is not transmitted so as to affect the displacement (change) on the piezo actuator 41 side.

That is, the coupling 45 connects the distal end portion (left side) of the feed screw shaft 33 and the distal end portion of the piezo actuator 41 so as to be relatively rotatable, and does not hinder the relative rotation of both distal ends in the X direction. The relative position can be kept constant. That is, in the X direction, it can be handled integrally.

The responsive displacement permitting means is such that the portion of the feed screw shaft 33 screwed with the nut member 34 responds to the expansion and contraction of the piezo actuator 41 in the X direction, and
In this embodiment, the piezo actuator 41 is allowed to be displaced (Xs) by the amount of expansion and contraction (Xs) of the piezo actuator 41. In this embodiment, the base end (right side) of the feed screw shaft 33 and the motor shaft 31
It is constructed by using a coupling 35 provided between S and S.

As shown in FIGS. 4 and 6, this coupling 35 has a notch groove having a plurality of notch grooves 35S spaced apart in the X direction and circumferentially displaced in a hollow cylindrical body 35T having a circular cross section. It has a cylindrical shape and can transmit the rotation of the motor shaft 31S to the feed screw shaft 33. During the rotation transmission, the dimension in the X direction is constant unless a forced external force in the X direction is applied. Regardless of whether it is in the middle or not, if a forced external force is applied, the dimension in the X direction can be changed by a minute amount.

That is, the drive shaft (31S) and the driven shaft (3
Focusing on the form and function of a common notched grooved coupling (35) that absorbs misalignment and runout with 3), it is introduced as a displacement permitting member (responsive displacement permitting means). In the case of this embodiment, the notched grooved cylindrical coupling 35 is a miniature coupling (set screw type (CPLS) ... made of stainless steel) manufactured by MISUMI Co., Ltd., having a diameter of 12 mm, a length of 18.5 mm, and a common use. The torque is 0.
3N · m, maximum rotation speed 32000 rpm, static torsional spring constant 64 N · m / rad, and allowable eccentricity 0.10.
It is.

The number of the notched grooves 35S is four, each set being displaced in the circumferential direction, for a total of eight of the two sets. According to the measurement by the applicant, when a forced external force (corresponding to the extension force from the piezo actuator 41) is applied from both ends in the stationary state, the dimension (length) can be reduced by about 0.8 mm at the maximum and the forced external force can be removed. For example, it has been confirmed that the original size (18.5 mm) is restored by elastic return. Therefore, if the initial state is shortened by, for example, 0.5 mm, it is easy to expand and contract by, for example, ± 0.2 mm in the axis (X) direction based on the state.

The responsive displacement permitting means may be formed by a coupling (35) with a torsion spring or bellows interposed in the middle. The responsive displacement permitting means (35) may be mounted in the middle of the feed screw shaft 33 and closer to the stepping motor 31 than the screw position with the nut member.

Further, as shown in FIG. 6, the coarse movement adjustment displacement detecting means and the fine movement adjustment displacement are utilized by utilizing the accommodation space SP between the base 10 and the table 20 and the hollow portion 15 and the through portion 16 on the base 10 side. One displacement detecting means 80 which also serves as the detecting means is built in. The displacement detecting means 80
It can be detected with an accuracy (resolution) of nm.

That is, the displacement detecting means 80 is attached to the lower surface side of the table 20 and is capable of adjusting moire after assembly using an adjusting screw (not shown), and the upper surface of the base 10 as shown in FIG. A detection head 82 including an index scale 84 and a light emitter / receiver shown in FIG. 4 and a detection circuit 83, an NI multiplication circuit 90 shown in FIG. 10, and an N2 division circuit shown in FIG. 100 and the N2 dividing circuit 10
It comprises a feedback signal generation and output circuit (not shown) for generating and outputting a 1 nm pulse signal from a digital detection signal which is an output of 0.

The main scale 81 is provided with a reflection-type first grating, and the index scale 84 is provided with a transmission-type second grating and four third gratings having a phase shift of 90 degrees. The gratings are gathered in one place and arranged close to the second grating in the longitudinal direction (or the width direction) of the index scale 83, and the light receiver (82A, 8A in FIG. 10) is used.
2RA, 82B, and 82RB) are formed by dividing a one-chip light-receiving element into four parts, and furthermore, a single condensing lens is attached to the light-emitting element that forms the light-emitting device, and the light-receiving element is inclined.

Therefore, the distance between the light receiving elements and the effective light receiving area can be greatly reduced, and the temperature characteristics of each light receiving element,
Since the deterioration characteristics can be made uniform, high resolution (for example, 100 nm or less) and high accuracy in performance can be achieved, and reduction in size and weight and cost in use can be achieved. In addition, since the light receiving energy of each light receiving element can be increased, the detection speed can be increased, and the gap between the scales 81 and 84 can be increased to make the graduation pitch of the first grating finer, so that the size and cost can be further reduced. And handling becomes very easy.

The detection head 82 is shown in FIGS.
And the roll angle is 4.0 minutes and the pitch angle is 2.4 minutes or less. As shown in FIG. 10, the detection circuit 83 includes each light receiver (element) in the detection head 82.
An operation of receiving four amplifiers 83A, 83RA, 83B, and 83RB to which 82A, 82RA, 82B, and 82RB are connected and the amplified photoelectric conversion signals Sa and Sra, and generating and outputting an A-phase analog detection signal Ax at a terminal. It is formed of an amplifier 83E and an operational amplifier 83F which similarly generates and outputs a B-phase analog detection signal Bx at a terminal. In addition,
The light-emitting device (element) is not shown.

The two analog detection signals Ax and Bx output from the detection circuit 83 and having a phase difference of 90 degrees in the form of a sine wave.
Can be multiplied and divided and digitally processed
The relative displacement between the movable body (20) and the stationary body (10) can be detected with high accuracy (1 nm). Further, the direction of displacement can also be detected.

Here, the N1 multiplying circuit 90 corresponds to FIG.
0, a first doubling circuit 90A that performs doubling processing
And a second doubling circuit 90B having the same structure. In FIG. 10, a capacitor for noise prevention and the like are not shown.

In FIG. 10, a first doubler 90A
Is a first multiplier 91 that multiplies the one analog detection signal Ax and the other analog detection signal Bx output from the detector (detection circuit 83), and the difference between the one analog detection signal Ax and the other analog detection signal Bx. A first sum-difference calculator 92 for calculating (Ax-Bx) and an analog detection signal Bx
And the difference between the inverted value of the analog detection signal Ax [Bx−
(−Ax)], and a second multiplier 96 that multiplies the difference (Ax−Bx) by the difference [Bx − (− Ax)]. On the other hand, the analog detection signal A
Each of the analog detection signals Ax2 and Bx2 having a frequency which is twice the frequency of x and the other analog detection signal Bx is generated and output.

In this embodiment, the first sum-difference calculator (N
1) The 92 and the second sum-difference calculator (N3) 94 are formed of operational amplifiers (μPC844... Made by NEC). The same applies to the inverting amplifier (N2) and the non-inverting amplifiers (N4, N5). Further, the first multiplier 91 and the second multiplier 96 are formed from analog multipliers (AD633: manufactured by Analog Devices, Inc.).

That is, one analog detection signal Ax from the detection circuit 83 is represented by [Equation 1] and the other analog detection signal B is
x is [Equation 2]. x is the displacement in the X direction, and P is the scale pitch of the main scale 81 (3.2 nm). Since the analog detection signals Ax and Bx are optically divided into two, the one-cycle pitch is 1.6 μm as shown in FIG.

(Equation 1)

(Equation 2)

Then, for simplicity, 2πx / P = α...
When Equation 1 is set, [Equation 1] is expressed as Ax = Sinα (−Ax =
−Sinα) Expression 2 is obtained, and [Equation 2] is expressed as Bx = Cos
α = Sin (α + π / 2) Expression 3 is obtained.

Here, the difference (Ax-Bx) between the analog detection signals Ax and Bx is the difference between Expressions 2 and 3, and is given by [Equation 3]. The calculation is performed by the first sum-difference calculator 92. Similarly, the difference [Bx − (− Ax)] becomes [Equation 4]. Second
Is calculated by the sum-difference calculator 94.

(Equation 3)

(Equation 4)

Thus, (Ax × B
x), Ax2 = Si as shown in FIG.
n (4πx / P)... The second multiplier 9
6 is multiplied by the difference (Ax−Bx) and the difference [Bx − (− Ax)], and Bx2 = Sin (4πx / P + π / 2)...

(Equation 5)

(Equation 6) In other words, letting [Equation 5] and [Equation 6] be operated, and omitting the constant terms on the right side thereof and simplifying them,
2α = β... Putting into Equation 6 and substituting Equation 6 into Equation 4, Ax
2 = Ax × Bx = Sinβ Expression 7 is obtained. When Expression 6 is substituted into Expression 5, Bx2 = (Ax−Bx) × [Bx−
(−Ax)] = Sin (β + π / 2) Equation 8 is obtained. That is, frequency conversion can be performed as shown in FIG.

By the way, since β = 2α = 4πx / P, it can be understood that Equations 7 and 8 are twice as long as Equations 2 and 3.

When the outputs (Ax2, Bx2) of the first doubling circuit 90A are input to the second doubling circuit 90B, the same doubling process as in the case of the first doubling circuit 90A is repeated. The analog detection signals Ax and Bx having a cycle pitch of 1.6 μm shown in FIG.
(= 4) Since the quadrupling process is performed by the multiplying circuit 90 (90A, 90B), the analog detection signal Ax4 having a cycle pitch of 0.4 μm shown in FIG.
It can be converted to Bx4 (multiplication processing).

The multiplying process may be formed such that only one stage or a plurality of (three or more) stages are repeated depending on the selected values of the scale pitch and the final resolution.

Next, the analog detection signal Ax after the multiplication is
4, Bx4 is divided by N2 (= 400) dividing circuit 100 into 400
When the division processing is performed, a digital detection signal having a cycle pitch of 40 nm shown in FIG. 12C can be obtained. The feedback signal generation and output circuit (inside 70) captures each rising edge of the digital detection signal and generates and outputs a 1-nm pulse signal.

Referring to FIG. 13, a controller 70 forming a drive control system includes a personal computer 7 including a database 76.
5, a coarse motion adjustment amount corresponding signal is output to the motor driver based on a command from
The intermediate adjustment can be performed while outputting a signal corresponding to the intermediate adjustment amount to the motor driver as a digital detection signal as a feedback signal, and a signal corresponding to the fine adjustment amount to the piezo driver as a feedback signal using the digital detection signal from the displacement detecting means 80 as a feedback signal It is formed so that fine movement adjustment can be performed while outputting. That is, FIGS. 16 (B), (C), (D)
The positioning control in the three-stage control mode shown in FIG.

Further, in this embodiment, the controller 70 performs the correction (error correction) using the command from the personal computer 75 including the database 76 and the error data stored in the ROM 74 (error correction), as shown in FIGS. ) Can perform high-speed positioning control in the two-step control mode.

Two-step control mode effective for high-speed positioning when the feed error of the ball screw structure (33, 34) is small or when the full stroke of the feed screw shaft 33 is short, and when the feed error is relatively large And the three-step control mode effective when the full stroke is long can be selectively switched by key operation.

Thus, the keyboard of the personal computer 75
Considering the two-step control mode, the positioning set amount (Xls = X
l + Xs), positioning setter, coarse movement adjusting means 3
Coarse adjustment setter using only 0 and setting coarse adjustment (Xl), fine adjustment setter using only fine adjustment means 40 and setting fine adjustment (Xs), setting coarse / fine adjustment direction And a speed setting device for setting a moving speed at the time of coarse (fine) movement adjustment.

Considering a three-stage control mode, the above-mentioned positioning setting device is set to a positioning set amount (Xlms = Xl + X
m + Xs) is settable, and the intermediate adjustment amount (Xm) is obtained by feedback control using only the coarse movement adjusting means 30 and using a digital detection signal from the displacement detecting means 80.
Are also formed. Incidentally, reference numeral 79 in FIG. 13 denotes a printer.

Now, the two-step adjustment mode uses the feed screw shaft 3
When the stepping motor 31 connected to the feed screw shaft 33 is rotationally driven, the target position is set to the error data corresponding to the target position. As a corrected target position corrected by using the above, the coarse movement adjustment by the feedback control can be executed. The corrected target position functions effectively also in the case of fine adjustment using the piezo actuator 41.

Therefore, in the case of the positioning setting performed by setting the positioning amount (Xls) with respect to the reference position, the coarse adjustment and the fine adjustment shown in FIGS. It is done on a regular basis. In the case of the coarse movement adjustment setting, only the coarse movement adjustment is possible, and in the case of the fine movement adjustment setting, only the fine movement adjustment is possible.

That is, the ball screw structure (33, 34)
For the full stroke in the X direction, error data in which the feed characteristic (or error) of the ball screw structure is associated with the number of pulse signals for driving the stepping motor is manually or automatically stored. A table in which displacement-error can be written may be formed so as to be automatically created in cooperation with the displacement detection means 80.

Then, when the stepping motor 31 is driven to rotate, coarse adjustment is executed as a corrected target position (the number of pulse signals) obtained by correcting the target position with error data corresponding to the target position. Therefore, only the one-step control shown in FIGS. 14B and 14C is performed in comparison with the three-step control shown in FIGS. 16B, 16C and 16D similar to the conventional example. Therefore, the positioning speed with a resolution of 1 nm can be further increased.

Next, the operation and operation of this embodiment will be described. First, a bias signal is output from the controller 70 shown in FIG. 13 to the piezo driver, and a voltage of 75 V is applied to the piezo actuator 41. Then, since the base end is fixed to the base 10 (backup block 74), the front end of the piezo actuator 41 extends 3.75 μm to the right in FIG.

Therefore, the dimensions of the cylindrical coupling 35 with the notch groove provided between the base end of the feed screw shaft 33 and the motor shaft 31S that cannot be displaced in the axis (X) direction (18.
5 mm) shrinks by 3.75 μm. Therefore, based on this state, it is understood that it is extremely easy to expand and contract by, for example, ± 20 nm in the axis (X) direction by applying (reducing) a forced external force to the coupling 35.

Then, using the knob 31T, the motor shaft 3
1S and the feed screw shaft 33 are rotated, and the table 20 is positioned at the reference position (retreat limit) where the limit switch 87 in FIG. At this time, the urging means 60 (the locking piece 66, the tension spring 65, the locking piece 67) urges the table 20 rightward in FIGS. That is, the distal end of the feed screw shaft 33 is urged toward the coupling 35 via the nut member 34.

The relative position in the X direction between the tip (left side) of the feed screw shaft 33 and the tip (right side) of the piezo actuator 41 is kept constant via the coupling 45. Backlash between the feed screw shaft 33 and the nut member 34 can also be removed. In this state, a counter (not shown) forming a part of the displacement detecting means 80 (detector) is cleared to zero.

Here, it is assumed that the three-step control is selected and the table 20 is positioned at a position advanced by, for example, +1 μm (= Xl + Xm + Xs) to the left in FIGS. 1, 3, and 6 from the reference position (retreat limit). Think.

Using the positioning setting device on the keyboard (operation panel) shown in FIG. 13, the positioning amount (1 μm = Xlms =
1000 nm). For example, Xl = 950n
m, Xm = 48 nm and Xs = 2 nm. The moving speed is also set using a speed setting device. Further, if necessary, the moving direction is set using a direction setting device. However, when the positioning amount is set as plus (+) 1 μm, the moving direction need not be set.

When the positioning command is issued, the controller 70 confirms that the positioning is set based on the database 76 in the personal computer 75, and determines the positioning set amount (+1).
.mu.m), and outputs a signal Sl (number of pulses) corresponding to the coarse adjustment amount (Xl = 950 nm) to the motor driver.

That is, since the drive power (current) is supplied via the cable Cm and the connector 39, the stepping motor 31 is driven in a predetermined direction (for example, in the rightward rotation direction).
To rotate. The coupling 35 transmits a rotational force to the feed screw shaft 33 as a coupling function.

Therefore, as the feed screw shaft 33 rotates, the table 20 is moved leftward (coarse movement) in FIG. 6 via the nut member 34 as shown in FIG. 16B. At this time, since the rotation of the feed screw shaft 33 is not transmitted to the piezo actuator 41 by the action of the miniature bearing 46 in the coupling 45, there is no problem.

When the table 20 moves (coarse movement) in the X direction (left direction), the main scale 81 attached to the table 20 shown in FIG. 5 naturally moves leftward. That is, the displacement detecting means 80 shown in FIGS. 3 and 6 including the index scale 83 on the base 10 facing the main scale 81 outputs a moving displacement detection signal Xi that changes every moment, that is, a digital detection signal having a resolution of 1 nm. Is done. However, at this stage (coarse movement adjustment), since the open control of the stepping motor 31 is performed for speeding up, it does not work as a feedback signal.

When the personal computer (CPU) 70 finishes outputting the signal Sl equal to the positioning set amount (Xl = + 950 nm), the personal computer (CPU) determines the switching point and stops the rotation of the stepping motor 31. Subsequently, the number of pulses corresponding to the set amount (Xm = 48 nm) is output for the intermediate adjustment as the feedback control of the stepping motor 31 according to FIG. In other words, it moves within the in-position range (for example, ± 10 nm) of FIG.

Here, based on the relationship between the minimum step angle of the stepping motor 31 and the feed pitch between the feed screw shaft 33 and the nut member 34, the reference position (retreat limit) of the table 20 detected by the displacement detecting means 80 is used. (The coarse movement adjustment amount = X1 + Xm) is, for example, +1003 nm.
In other words, the coarse movement adjusting means 30 can perform positioning only with an accuracy on the order of 10 nm. In this case, with respect to the target position (1000 nm = 1 μm), +3 nm (= 1
003-1000).

Then, the CPU calculates the error (+3 nm)
In order to cancel the error, the voltage (75 V) applied to the piezo actuator 41 is changed to cancel the error-equivalent feedback signal (Xi) from the displacement detecting means 80 by, for example, 60
The driving voltage is increased by mV (corresponding to 3 nm) (75.060
V). The feedback control of FIG. 16D is performed.
Therefore, the piezo actuator 41 has a base end (left side) as a fixed end, and a front end (right side) extends rightward in FIG. 6 by 3 nm.

At this time, the distal end of the piezo actuator 41 and the distal end of the feed screw shaft 33 cannot be displaced in the X direction via the coupling 45, that is, the relative position is constant. Axis 33
A leftward external force is applied to the responsive displacement permitting means (the cylindrical coupling 35 with the notched groove) via the through hole to contract it.

Thus, the coupling 35 is moved to the right in FIG.
Reduce by nm. That is, the entire feed screw shaft 33 is shown in FIG.
To move (displace) to the right, and displace the position of the feed screw shaft 33 screwed to the nut member 34 to the right.

That is, the nut member 34 is integrally connected to the table 20 by the leaf spring 21 or the like, and the urging means 60
(Tension spring 61) connects feed screw shaft 31 to coupling 35
Direction, the ball screw structure (31, 3
2) There is no backlash, and the table 20 is moved rightward by 3
It can be displaced (returned) exactly by nm.

When the position shown in FIGS. 16B and 16C is not the above-mentioned +1003 nm, but is, for example, +998 nm, the voltage applied to the piezo actuator 41 is reduced, and the responsive displacement permitting means (35) is shown. 6 to 2 nm to the left
The feedback control shown in FIG.

That is, the digital detection signal (Xi) from the displacement detecting means 80, that is, the actual detected displacement amount is (100).
If it is (0 ± 1 nm), the fine movement adjustment ends. That is,
± 1 for the set position (1 μm = 1000 nm)
High-precision positioning in nm.

In the case of the two-step control shown in FIGS. 14B and 14C, the corrected target position (1000 nm ± α) for canceling the error data in the first step [(B)] is set as the target position. (For example, +995 nm), the stepping motor 31 is feedback-controlled from the beginning to make coarse adjustment so as to fall within the in-position range (for example, ± 10 nm). After that, coarse adjustment (C) is controlled in three stages [FIG.
(D)]. Thus, high precision 1n
Positioning at m can be further speeded up. Thus, according to this embodiment, the coarse movement adjusting means 30, the fine movement adjusting means 41 utilizing the expansion and contraction of the piezo actuator 41,
A displacement detector (80) that includes a main scale 81, an index scale 84, and a light emitting and receiving device and that can output two analog detection signals; N1 multiplying circuit 90 (90) that multiplies one cycle pitch by four in a synchronized state
A, 90B) and an N2 division circuit 100 that generates a digital detection signal obtained by dividing one cycle pitch of each multiplied analog detection signal by 400, so that it is very inexpensive and has a high precision of 1 nm resolution. Can be positioned.

The scale pitch of the main scale 81 is 3.2 μm, and one cycle pitch of each analog detection signal output from the detector (83) is 1.6 μm optically divided into two and 1.6 μm. Since the phase shift is 90 degrees, the multiplication integer N1 of the N1 multiplication circuit 90 is 4 and the division integer N2 of the N2 division circuit 100 is 400, the scale pitch of the main scale 81 is 1.6 nm.
As compared with the case where there is no problem in the electron beam lithography production and the transfer duplication is easy, it can be embodied at a lower cost, and the N1 multiplier 90 is also a two-stage process using four multipliers. The N2 division circuit 100 may be the same as that of the conventional example (400 division). And base 1
0 and the table 20 can be assembled relatively easily and reliably.

The N1 multiplying circuit 90 includes a first multiplier 91, a first sum-difference calculator 92, and a second sum-difference calculator 9.
And a second multiplier 96, which can generate and output each analog detection signal having a frequency that is twice the frequency of one analog detection signal Ax and the other analog detection signal Bx.
, And a second doubling circuit 90B having the same structure as the first doubling circuit 90A.
Are the commercially available operational amplifiers and
In addition, since the second multipliers 91 and 96 can be constructed with commercially available analog multipliers, the cost can be further reduced and the reliability is improved.

Further, since the driving voltage per 1 nm of the amount of expansion and contraction of the piezo actuator 41 is set to 20 mV or more, even if the ripple and the like of the power supply device for the piezo actuator are the same as those in the conventional example, 1 nm feedback control is performed. Can be reduced or eliminated.

Further, the feed screw shaft 33 and the nut member 3
4, the error data in the X direction can be stored in the ROM 74, and when the stepping motor 31 is rotationally driven, the coarse movement adjustment can be performed as a corrected target position obtained by correcting the target position with error data corresponding to the target position. Since it is formed, the conventional two-stage control shown in FIGS. 16B and 16C can be replaced with only one-stage control equivalent to the same one shown in FIG. Speed can be further increased.

Further, the nut member 34 is positioned on the position regulating surface 20.
F and the leaf spring 21 and the table 20 in the X direction.
Since it is connected so as not to be displaceable relative to each other, it is possible to perform positioning with high accuracy of 1 nm even in a usage method in which the axis (X) is vertical, so that three-dimensional positioning can be performed by combining three units.

Further, the coupling 45 is connected to the feed screw shaft 3
Since it is not necessary to transmit the rotational force of No. 3 to the piezo actuator 41 side, it is very small. Therefore, the structure can be further simplified because the piezoelectric actuator 41 and the piezo actuator 41 can be accommodated in the accommodation space SP between the base 10 and the table 20.

Further, a responsive displacement permitting means (35) is mounted between the motor shaft 31S for applying a rotational force to the feed screw shaft 33 and the base end of the feed screw shaft 33, and is separated in the X direction. A notched grooved cylinder including a cylindrical body 35T having a plurality of notched grooves 35S displaced in the circumferential direction, capable of transmitting rotational force, and capable of expanding and contracting in the X direction by an expansion / contraction force (forced external force) generated from a piezo actuator 41. Since it is formed from the body-shaped coupling 45, it is only necessary to divert a conventional coupling (35) for absorbing misalignment and runout of the conventional example. Therefore, no burden is imposed on the layout and space.

Further, the piezo actuator 41, the coupling 45 and the responsive displacement permitting means (the cylindrical coupling 35 with the notch groove) constituting the fine movement adjusting means 40 are the same as the feed screw shaft 33 constituting the coarse movement adjusting means 30. Are arranged in series on the X-axis, and the positioning accuracy can be greatly improved with high response.

Further, the urging means 60 (65) is connected to the feed screw shaft 3 via the table 20 and the nut member 34.
3 is formed so as to bias the coupling member 3 toward the coupling 35 side, so that the backlash between the nut member 34 and the feed screw shaft 33 can be eliminated. From this point, the positioning accuracy can be further improved.

Further, the displacement detecting means 80 (82, 8)
3) is accommodated in the accommodation space SP and the hollow portion (15, 16) on the base 10 side, so that the scales 81, 84 and the like do not protrude and are exposed on the sides of the base 10 and the table 20. Therefore, not only can planar miniaturization and ease of handling be further promoted, but also since both scales 81 and 84 are relatively displaced on the axis (X), higher precision detection can be achieved.

Further, the displacement detecting means 80 comprises a main scale 81 having a reflection type first grating and a transmission type second scale 81.
An index scale 84 having a grating and four third gratings having a phase shift of 90 degrees, each of the third gratings being gathered in one place and being arranged close to the second grating in the longitudinal direction of the index scale 84; The light-receiving device is formed by dividing a one-chip light-receiving device into four parts, and furthermore, a single condensing lens is attached to the light-emitting device forming the light-emitting device, and the light-receiving device is inclined. Accuracy can be detected.

The motor is a stepping motor 31.
It is not limited to. For example, the present invention can be implemented by using an AC servomotor, a DC servomotor, or the like.

[0115]

According to the first aspect of the present invention, the base and the table, the coarse movement adjusting means including the motor, the fine movement adjusting means utilizing the expansion and contraction of the piezo actuator, and the displacement detecting means for detecting the table displacement. A displacement detecting means including a main scale, an index scale, and a light emitting and receiving device, capable of outputting two analog detection signals having phase shifts, and a one-cycle pitch of the two analog detection signals synchronized with N1. Since it is a positioning device composed of an N1 multiplier circuit for multiplying and a N2 division circuit for generating a digital detection signal obtained by dividing one cycle pitch of each analog detection signal after the multiplication by N2, it is very inexpensive and is based on a table. Can be positioned with a high accuracy of 1 nm.

According to the second aspect of the present invention, the scale pitch of the main scale is 3.2 μm, and one cycle pitch of each analog detection signal output from the detector is 1.6 μm which is optically divided into two. In addition, since the phase shift is 90 degrees with respect to each other, the multiplication integer N1 of the N1 multiplication circuit is 4 and the division integer N2 of the N2 division circuit is 400, the same effect as that of the invention of claim 1 can be obtained. In addition to being able to perform, stable positioning operation can be performed while further reducing costs by facilitating production and assembly.

According to the third aspect of the present invention, the N1 multiplying circuit includes a first multiplier, a first sum-difference calculator, a second sum-difference calculator, and a second multiplier. And a second doubling circuit capable of generating and outputting each analog detection signal having a frequency that is twice the frequency of the one analog detection signal Ax and the other analog detection signal Bx, and a second doubling circuit having the same structure as this. Since it is formed, claim 1 and claim 2
In addition to the effects similar to those of the inventions described above, the first and second sum-and-difference calculators are constructed with commercially available operational amplifiers, and the first and second multipliers are constructed with commercially available analog multipliers. Therefore, cost can be further reduced and reliability is improved.

Further, according to the invention of claim 4, the driving voltage per 1 nm of the expansion / contraction amount of the piezo actuator is 20.
Since the voltage is set to mV or more, the same effects as those of the inventions of claims 1 to 3 can be obtained. In addition, the ripple and the like of the power supply device for the piezo actuator are the same as those of the conventional example. Even if
The influence of noise on the m feedback control can be reduced or eliminated.

Further, according to the fifth aspect of the present invention, error data in the axial direction of the feed screw shaft and the nut member can be stored, and when the stepping motor is driven to rotate, the target position is set to an error corresponding to the target position. Since the coarse movement adjustment can be executed as the corrected target position corrected by the data, the same effects as those of the inventions according to the first to fourth aspects can be obtained. Since the two-step control shown in FIGS. 16B and 16C is required, only the one-step control corresponding to FIG. 16C can be performed, so that the positioning speed at a resolution of 1 nm can be increased.

Furthermore, according to the invention of claim 6, the nut member is connected to the table in the axial direction using the position regulating surface and the leaf spring so as not to be relatively displaceable. In addition to achieving the same effects as in each of the inventions up to Item 5, the positioning can be performed with high accuracy of 1 nm even in a usage method in which the axis is perpendicular. Therefore, three-dimensional positioning can be performed by combining three units.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is also a right side view.

FIG. 3 is also a front view.

FIG. 4 is a plan view showing a state where a table is removed.

FIG. 5 is a view of the table as viewed from below.

FIG. 6 is also a center vertical sectional view.

FIG. 7 is a view for explaining a state in which the nut member is integrally attached to the table.

FIG. 8 is also a diagram for explaining a limit detection unit.

FIG. 9 is a diagram for explaining a displacement detection unit.

FIG. 10 is a circuit diagram for explaining a detector and an N1 multiplier circuit.

FIG. 11 is a diagram for explaining a waveform of an analog detection signal before and after N1 multiplication processing.

FIG. 12 is a diagram for explaining a process of obtaining a 1-nm digital detection signal by the N1 multiplication process and the N2 division process.

FIG. 13 is a diagram for explaining a drive control system.

FIG. 14 is a diagram for explaining coarse movement adjustment and fine movement adjustment.

FIG. 15 is a plan view showing a state in which a table for explaining a conventional example is removed.

FIG. 16 is a diagram for explaining coarse movement adjustment and fine movement adjustment in the case of the conventional example.

FIG. 17 is a view for explaining a conventional displacement detecting means.

FIG. 18 is a diagram for explaining an attachment angle of the detection head with respect to the main scale.

FIG. 19 is a diagram for explaining an attachment angle allowable error range.

[Explanation of symbols]

 Reference Signs List 10 base 20 table 20F position regulating surface 21 leaf spring 30 coarse movement adjusting means 31 stepping motor (motor) 33 feed screw shaft (ball screw structure) 34 nut member (ball screw structure) 35 coupling (responsive displacement permitting means) 40 fine movement Adjusting means 41 Piezo actuator 45 Coupling 46 Miniature bearing 60 Urging means 65 Tension spring 70 Controller 74 ROM 75 Personal computer 80 Displacement detecting means 81 Main scale 81F Scale surface 82 Detection head (detector) 83 Detection circuit (Detector) 84 Index Scale 90 N1 multiplier 90A First doubling circuit 90B Second doubling circuit 91 First multiplier 92 First sum-difference calculator 94 Second sum-difference calculator 96 Second multiplier 100 N2 division Circuit 100P division times X axis x X-direction displacement P main scale pitch

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Souji Ichikawa 107-6 F Term, Iruma City, Saitama 2F069 AA02 AA06 BB13 BB40 DD19 GG04 GG07 HH09 HH14 JJ06 JJ13 MM07 MM34 MM38 NN21 NN22 PP01 2F103 BA37 CA03 CA03 DA01 DA12 EA01 EA15 EA17 EB16 ED02 ED03 ED04 FA06 FA09 GA01 5H303 AA20 BB01 BB07 BB11 BB17 CC01 DD01 DD03 DD14 DD25 EE01 EE03 FF06 GG11 HH01 KK31 LL03

Claims (6)

[Claims] 1. A table comprising: a base and a table mounted so as to be relatively movable in an axial direction; a feed screw shaft mounted on a base side; and a nut member mounted on a table side, the table being axially moved relative to the base. Coarse adjustment means for performing coarse adjustment, fine adjustment means for finely adjusting the table relative to the base in the axial direction by using expansion and contraction of the piezo actuator after coarse adjustment, and at least fine adjustment for the fine adjustment means. A displacement detection means for detecting a table displacement for a feedback signal to be detected, wherein the displacement detection means comprises a main scale attached to one of the base and the table, and an index attached to the other. A detector that can output two analog detection signals that are out of phase, including a scale and N1 multiplying circuit including two multipliers and N1 multiplying one cycle pitch of two analog detection signals input from the detector in synchronization with each other, and multiplying each analog detection signal input from the N1 multiplier circuit And a N2 division circuit for generating a digital detection signal obtained by dividing one cycle pitch by N2. 2. The scale pitch of the main scale is 3.2 μm, and one cycle pitch of each analog detection signal output from the detector is 1.6 μm optically divided into two and 90 ° mutually. The multiplied integer N1 of the N1 multiplier circuit is 4 and the N1
2. The positioning device according to claim 1, wherein the divided integer N2 of the two-divided circuit is 400. 3. A first multiplier for multiplying the one analog detection signal Ax and the other analog detection signal Bx output from the detector by the N1 multiplier circuit, and the one analog detection signal Ax and the other analog detection signal Difference from Bx (Ax−
Bx), and a second sum-difference calculator for calculating a difference [Bx − (− Ax)] between the other analog detection signal Bx and the inverted value of the one analog detection signal Ax. ,
A second multiplier for multiplying the difference (Ax-Bx) by the difference [Bx-(-Ax)], while the analog detection signal A
x and the first 2 which can generate and output each analog detection signal having a frequency which is twice the frequency of the analog detection signal Bx
3. The positioning device according to claim 1, wherein the positioning device is formed of a multiplying circuit and a second doubling circuit having the same structure. 4. The expansion and contraction amount of the piezo actuator is 1n.
4. The positioning device according to claim 1, wherein a driving voltage per m is 20 mV or more. 5. An axial error data of the feed screw shaft and the nut member can be stored, and a target position is set when a stepping motor forming the motor connected to the feed screw shaft is rotationally driven. The positioning device according to any one of claims 1 to 4, wherein the coarse movement adjustment is performed as a corrected target position corrected by error data corresponding to the target position. 6. The table according to claim 1, wherein the nut member is connected to the table by using a position regulating surface and a leaf spring on a lower surface of the table so that the nut member cannot be relatively displaced in the axial direction. A positioning device according to any one of the preceding claims.