JP2001311789A - Precise feeder for moving stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a feeder for a moving stage, having extremely small feeding irregularity. SOLUTION: The feeder comprises a container storing an electroviscous fluid, at least one moving plate, at least the part of which exists in the electroviscous fluid, adapted to move, the moving stage having the moving plate, a power supply part for applying an electric field substantially perpendicular to the moving direction of the moving plate and corresponding to the moving speed of the moving stage to the electroviscous fluid, and a drive part for driving the movement of the moving stage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision feeding device for a moving stage, such as an optical disk master making / manufacturing device or a stepper, which requires a high precision feeding.

[0002]

2. Description of the Related Art CD or DVD (Digital Ve)
Abbreviation of rsatile disc. Registered trademark. ), The demand for CDs or DVDs on which content such as music or movies is recorded is growing. Optical disks such as CDs and DVDs sold in the market are manufactured by stamping from a master on which signals are recorded. An optical disc mastering device (master disc creating device) is manufactured by a known photoelectroforming method. Clean the glass disk and coat the cleaned disk with photoresist. The photoresist coated disc is baked to remove the photoresist solvent and harden the photoresist. A signal is recorded on the baked disk using a laser beam.

[0003] The recorded disk is developed. By the development, a portion of the photoresist irradiated with the laser beam is removed. Ni is sputtered on the developed disk because the glass disk is non-conductive and a conductive film must be formed for the next electroforming. Electroforming (electroforming) is performed on the sputtered disk to generate a master on the disk. The back of the electroformed master is polished and peeled from the glass disk. Remove the hole in the center axis of the peeled master. The punched master is cleaned to remove photoresist and the like remaining on the surface. The master is completed through the above steps. Thereafter, a stamper is generated from the master, and stamping is performed by the stamper, thereby duplicating the optical disk.

[0004] An optical disk master recording device (laser beam recorder) is used in the step of recording a signal on a master using a laser beam in the above steps. FIG.
Reference numeral 7 denotes a schematic configuration of an optical disk (DVD or the like) master recording apparatus. 101 is a laser oscillator, 102 is a spindle motor, 103 is a slider, 104 is a recording lens, 105 is a beam spot monitor, 106 is a moving optical system, 107 is a DVD master, and 108 is a vibration isolation table. Ultraviolet laser light (eg, argon laser light) output from the laser oscillator 101 is modulated by a digital video signal or digital audio signal or the like, passes through the moving optical system 106, and passes through the recording lens 104 (included in the moving optical system 106). Then, the light is irradiated onto the master 107 rotating by the spindle motor 102.

[0005] While the master is rotated by the spindle motor 102 and the slider 103 is slowly moved in the radial direction of the master 107, the moving optical system 106 including the recording lens 104 mounted on the slider 103 is moved. Laser beam master 10
7 and record the signal. DVD is a CLV system (Constant Li) that records data at a constant density.
near Velocity method. (Constant linear velocity method), the rotation speed of the spindle motor 102 is different between the inner circumference and the outer circumference of the disk. Accordingly, the moving speed of the slider 103 also differs between the inner circumference and the outer circumference of the disk. For example, in the master recording apparatus shown in FIG.
Moves at a low speed of 5 μm / s on the outer circumference of the disk, and moves at a high speed of 10 μm / s or more on the inner circumference of the disk.

[0006] The reflected light of the laser light applied to the master is input, and the beam spot monitor 105 detects the signal level of the reflected light. The height of the recording lens is adjusted optimally based on the detection output. Since the master recording apparatus performs highly accurate processing, it is necessary to remove the influence of disturbance. Main components 101 to 10 of master recording device
6 is placed on an anti-vibration table 108 mounted on a damper mechanism that absorbs vibration due to disturbance.

[0007] With the advance of technology for performing high-density recording on an optical disk, the track pitch of the optical disk has become very narrow. The track pitch of the CD was 1.6 μm, while the track pitch of the DVD was 0.74 μm.
The track pitch of an HD-DVD for recording a D image signal is around 0.4 μm. It is considered that an optical disk having a narrower track pitch will be standardized in the future. As the track pitch of the optical disk becomes narrower, the allowable value of the speed unevenness of the slider 103 of the master recording apparatus becomes very narrow (high accuracy is required). It is necessary that a DVD reproduced from a master created by a master recording device can be completely reproduced by any DVD reproducing device. Specifically, the fluctuation of the track pitch of the manufactured DVD master is reduced by about 20
nm. Moreover, considering that an optical disk having a track pitch will appear in the future, it is desirable that the fluctuation of the track pitch of the master be set to several nm or less. In order to realize such accuracy, it is not possible to tolerate minute unevenness in feed caused by disturbance such as vibration of cooling water of a recording laser or floor vibration generated from a peripheral processing device.
For example, a static pressure air bearing has a disturbance vibration of about 500 Hz, and a water hammer by laser cooling water has a size of about 30 to 1.
A disturbance vibration of 00 Hz and a disturbance vibration of 3 to 4 Hz are generated on the vibration isolation table.

According to the present invention, the track pitch fluctuation is several nm.
The present invention relates to an optical disk master recording apparatus capable of manufacturing the following master, and more particularly, to a feeder including a slider (moving stage) of such an original master recording apparatus. Further, the present invention can be applied to any device (for example, a semiconductor stepper or the like) that requires a high-precision moving stage feeder.

As described above, in recent years, as optical discs and semiconductors have become more precise, there has been a strong demand for higher precision feeders for producing them. A high-precision moving stage feeder generally includes a hydrostatic bearing guide, a linear motor or a piezoelectric element for driving the guide, and a positioning scale or a laser scale mounted on the guide, and information on the scale. Is fed back to control the position, speed and acceleration of the guide. However, even with this configuration, only the place where the scale is located is precisely driven to the last, and the fine play of the guide and the resonance of the air occur in the static pressure bearing at the place apart from the scale, and several nanometers It causes micro vibration.

As a known technique in which an electrorheological fluid is applied to a damper device, there is JP-A-7-83266. JP 7
According to -83266, the viscosity of the electrorheological fluid is changed by applying a voltage to the electrorheological fluid filling the space between the electrode fixed to the slide mechanism and the movable electrode only when the slide mechanism is stopped. Prevent minute vibration and stop the slide mechanism accurately. However, when a mechanical load is applied to the moving stage, a change in the load accompanying the movement of the moving stage causes a new disturbance.

As a means for solving this problem, a moving stage having a feed guide using a hydrostatic air bearing and obtaining a feed resistance using an electrorheological fluid has been proposed. Volume C, Vol. 65, No. 630 (199)
9-2) Paper No. 98-0962). The method of obtaining the feed resistance using the electrorheological fluid can be used effectively because the resistance can be freely changed by the applied voltage. In the master recording of an optical disk, the head is moved at a rapid feed rate of several mm or more per second to the recording zone, and the recording zone needs to be fed at a very low speed of several μm per second. If an electrorheological fluid is used, an ideal use can be realized by applying a voltage to the electrorheological fluid to reduce the resistance during fast-forwarding without applying a voltage, and applying a voltage during recording to make the state more damping.

[0012]

Conventionally, to control an electrorheological fluid, a voltage has been applied or a constant electric field has been applied to the electrorheological fluid only at the time of starting and stopping. However, for example, in a master recording device such as a CLV optical disk, a signal is recorded using a laser so that the peripheral speed is constant. In order to process the master of the optical disk so that the track pitch of the recorded signal is precisely constant, it is necessary to change the moving speed of the slider (moving stage) according to the location of the master. However, the minute vibration of the moving stage changes according to the moving speed of the moving stage. In the related art, when the minute vibration changes according to the speed, the track pitch unevenness of the master optical disc cannot be made constant. The present invention provides a moving stage feeder for an optical disc master recording apparatus capable of suppressing speed unevenness of a moving stage and manufacturing an optical disc master having track pitch unevenness of several nm or less at any place on the master. It is intended to be realized. or,
SUMMARY OF THE INVENTION An object of the present invention is to realize a moving stage feeder having extremely small speed unevenness for use in any other device (for example, a semiconductor stepper or the like). Another object of the present invention is to realize a moving stage feeder that is efficient, easy to adjust, and safe.

[0013]

According to a first aspect of the present invention, there is provided a container containing an electrorheological fluid, and at least a part which is at least partially present in the electrorheological fluid and is movable. Moving plates, a moving stage having the moving plate, and applying an electric field in a direction substantially perpendicular to the moving direction of the moving plate, the electric field corresponding to the moving speed of the moving stage to the electrorheological fluid. And a driving unit for moving the moving stage.

In the moving stage feeder of the present invention, it is necessary that the track pitch unevenness be constant irrespective of the speed of the moving stage. Therefore, in order to keep track pitch unevenness, the voltage applied to the electrodes is variably controlled according to the moving speed of the moving stage. The present invention controls the voltage applied to the electrorheological fluid to suppress the swinging movement of the moving stage in the moving direction and the direction perpendicular to the moving direction, and realizes a moving stage feeder with small track pitch unevenness. Has the effect of being able to.

According to a second aspect of the present invention, there is provided a container containing an electrorheological fluid, at least one movable plate which is at least partially present in the electrorheological fluid and is movable, A first electrode and a second electrode for generating an electric field in a direction substantially perpendicular to the direction of movement of the moving plate, wherein the fixed first electrode and the fixed second electrode or the moving plate A second electrode, a power supply unit that applies a voltage to the first electrode and the second electrode, a moving stage having the moving plate, and a driving unit that moves the moving stage. A feeding device provided, wherein a distance between the first electrode and the second electrode changes according to a position of the moving stage in a moving direction.

In the present invention, the distance between the electrodes for applying an electric field to the electrorheological fluid changes according to the position of the moving stage in the moving direction. When a voltage V is applied between the electrodes at a distance d between the electrodes, an electric field E = V / d is generated. For example, in an optical disk master recording apparatus, it is preferable to change the damping amount according to the moving speed of the moving stage. The moving speed of the moving stage is determined by the position of the moving stage. Therefore, for example, by applying a constant voltage V between the electrodes and changing the distance d between the electrodes according to the position of the moving stage in the moving direction, the damping effect by the electrorheological fluid changes according to the position of the moving stage. Can be done. The present invention variably controls the electric field applied to the electrorheological fluid according to the position of the moving stage,
This has the effect of suppressing the swinging movement of the moving stage in the moving direction and the direction perpendicular to the moving direction, and realizing a moving stage feeder with small track pitch unevenness.

The voltage applied between the electrodes may not be constant (the same applies to the third and subsequent claims). Further, the feeder may have a plurality of first electrodes or a plurality of second electrodes (the same applies to the inventions of other claims). Also, the applied voltage may be a DC voltage,
An AC voltage may be used (the same applies to the inventions of other claims). Further, the present invention has an effect that an inexpensive moving stage feeder using a power supply unit that outputs a constant voltage or a voltage in a small change range can be realized.

The first electrode and the second electrode may be fixed together (for example, disposed in a container).
Further, the first electrode may be fixed (for example, disposed on a container), and the second electrode may move (disposed on a moving plate). The “second electrode disposed on the moving plate” may be, for example, a second electrode attached to the moving plate, or the moving plate itself may be the second electrode.

According to a third aspect of the present invention, there is provided a container containing an electrorheological fluid, at least one movable plate which is at least partially present in the electrorheological fluid and is movable, A first electrode and a second electrode for generating an electric field in a direction substantially perpendicular to the direction of movement of the moving plate, wherein the fixed first electrode and the fixed second electrode or the moving plate A second electrode, a power supply unit that applies a voltage to the first electrode and the second electrode, a moving stage having the moving plate, and a driving unit that moves the moving stage. A feeding device comprising: a feeding device, wherein an area of a portion where the first electrode and the second electrode face each other changes according to a position in a moving direction of the moving stage. is there.

In the present invention, the area of the part where the electrodes for applying an electric field to the electrorheological fluid oppose each other (the area where the electrodes overlap) changes according to the position of the moving stage in the moving direction. Assuming that the area of the portion where the two electrodes face each other is S and the shear stress per unit area where the electrorheological fluid is generated is τ, the damping force (resistance) fd acting on the moving plate can be expressed as fd = τ × S. . For example, by applying a constant voltage V between the electrodes and changing the area S of the portion where the electrodes face each other according to the position of the moving stage in the moving direction, the damping effect by the electrorheological fluid according to the position of the moving stage Can be changed.
The present invention variably controls the electric field applied to the electrorheological fluid in accordance with the position of the moving stage, thereby suppressing the moving direction, the swinging motion of the moving stage in a direction perpendicular to the moving direction, and reducing track pitch unevenness. This has the function of realizing a moving stage feeder. Further, the present invention has an effect that an inexpensive moving stage feeder using a power supply unit that outputs a constant voltage or a voltage in a small change range can be realized.

According to a fourth aspect of the present invention, the distance between the first electrode and the second electrode changes according to the position of the moving stage in the moving direction. A feed device according to claim 3, wherein the feed device is a feed device.

In the present invention, the area of the part where the electrodes for applying an electric field to the electrorheological fluid oppose each other (the area where the electrodes overlap) and the distance between the electrodes depend on the position of the moving stage in the moving direction. Change. This allows
The damping effect by the electrorheological fluid can be changed according to the position of the moving stage. The present invention variably controls the electric field applied to the electrorheological fluid in accordance with the position of the moving stage, thereby suppressing the moving direction, the swinging motion of the moving stage in a direction perpendicular to the moving direction, and reducing track pitch unevenness. This has the function of realizing a moving stage feeder. Further, the present invention has an effect that an inexpensive moving stage feeder using a power supply unit that outputs a constant voltage or a voltage in a small change range can be realized.

According to a fifth aspect of the present invention, there is provided a first container and a second container containing an electrorheological fluid, and at least a part of the first container and the second container exist in the electrorheological fluid of the first container. A movable first movable plate, a movable second movable plate at least partially in the electrorheological fluid of the second container, and the first movable plate A moving stage having the second moving plate, a power supply unit for generating an electric field in a direction substantially perpendicular to the moving direction of the first moving plate and the second moving plate, and a drive for moving the moving stage Wherein the vector of each stress generated by the electrorheological fluid on the first moving plate and the second moving plate includes a vertical axis including a center of gravity of the moving stage. Are substantially symmetrical to each other with respect to the plane, it is feeding apparatus according to claim.

The feeder of the present invention has an electrorheological fluid braking device (including a container, an electrorheological fluid, etc.) at symmetrical positions on both sides of the center line (including the center of gravity) of the moving stage. By disposing the electrorheological fluid on both sides of the moving stage, it is possible to prevent imbalance in vibration of the moving stage. The present invention suppresses the swinging motion of the moving stage in the moving direction and the direction perpendicular to the moving direction by applying balanced shear stress (resistance) to the moving stage, and feeds the moving stage with small track pitch unevenness. It has the effect that the device can be realized.

According to a sixth aspect of the present invention, the first container and the second container are interconnected.
The feed device according to claim 5, wherein:

When the liquid surface on both sides becomes unbalanced due to evaporation of the liquid or the like, unbalanced vibration occurs. In the feeder of the present invention, containers on both sides are connected by pipes or the like so that the liquid level of the electrorheological fluid provided on both sides of the moving stage is constant. This prevents the liquid level from becoming unbalanced. The present invention has the effect of realizing a moving stage feeder in which the balance does not deteriorate over time. Further, the present invention has an effect of realizing a moving stage feeder which does not require the balance adjustment of the amount of the electrorheological fluid to be put in the two containers.

[0027] According to a seventh aspect of the present invention, there is provided a slide movably disposed along a guide, a container containing an electrorheological fluid, and at least a part of the slide is present in the electrorheological fluid. At least one movable plate, a movable stage having the slide and the movable plate, and a power supply unit for applying an electric field to the electrorheological fluid in a direction substantially perpendicular to a moving direction of the movable plate. And a driving unit for moving the moving stage, wherein the vector of the driving force of the driving unit and the vector of the force exerted on the moving stage by the stress of the electrorheological fluid are: A feed device substantially existing on a vertical plane including a center of gravity of a moving stage.

In the feeder of the present invention, both the driving force and the braking force (resistance) of the moving stage are on a vertical plane including the center of gravity of the moving stage. These forces do not create a moment to rotate the moving stage. Therefore, the imbalance of the moving stage does not occur due to these forces. The present invention suppresses the swinging motion of the moving stage in the moving direction and the direction perpendicular to the moving direction by applying unbalanced driving force and shear stress (resistance), and feeds the moving stage with small track pitch unevenness. This has the effect of realizing the device. In a feeder having a plurality of braking devices having an electrorheological fluid (including a container, a moving plate, etc. each having an electrorheological fluid), a combined vector of the stress vectors of the plurality of braking devices is the center of gravity of the moving stage. What is necessary is to exist substantially on the perpendicular plane containing. Preferably, in a feeder having a plurality of braking devices, all stress vectors of the plurality of braking devices substantially exist on a vertical plane including the center of gravity of the moving stage (for example, the sixth embodiment). ). In this case, the present invention has an effect of realizing a moving stage feeder that does not require (or is easy to adjust) the balance between the driving force and the shearing stress.

The invention according to claim 8 of the present invention is characterized in that the surface of the moving plate has a surface roughness greater than the average value of the diameter of the dispersed particles in the electrorheological fluid. A feed device according to any one of claims 1 to 7.

It has been discovered that a smooth surface of the moving plate effectively reduces shear stress. The present invention has an effect that an efficient moving stage feeder can be realized. "Having a surface roughness greater than the average value of the diameter of the dispersed particles in the electrorheological fluid" means, for example, if the average value of the diameter of the dispersed particles is 5 μm, measured from the average height of the surface of the moving plate It means that the average value of the peak height of the uneven peaks on the surface or the depth of the bottom of the valleys is 5 μm or more.

According to a ninth aspect of the present invention, when the power supply of the feeder is cut off, two electrodes connected to the power supply section are short-circuited. A feeding device according to any one of the claims.

The present invention has an effect of realizing a safe moving stage feeder by always short-circuiting the electric charges accumulated in the electrodes when the power is cut off and discharging.

[0033] According to a tenth aspect of the present invention, the first electrode and the second electrode are replaced by a magnetic fluid instead of the electrorheological fluid.
The feeding device according to any one of claims 1 to 8, wherein the electrode (1) is replaced by a magnetic circuit having a gap.

The present invention uses a magnetic fluid instead of an electrorheological fluid. The present invention has the same effect as described in the above-described claim. In addition, when a magnetic fluid is used, there is no danger of electric shock or the like since no charge is accumulated in the electrodes.

[0035]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred embodiment of the present invention; The present invention obtains a feed resistance by moving a moving plate in an electrorheological fluid. The electrorheological fluid will be described. The electrorheological fluid is a liquid whose viscosity changes according to the intensity of an electric field generated by applying a voltage (referred to as a Winslow effect). Also referred to as ER fluid (Electrorheological Flui)
abbreviation of d). The electrorheological fluid includes a dispersed electrorheological fluid and a homogeneous electrorheological fluid. The electrorheological fluid of the dispersion system is composed of a dielectric fine particle (for example, a fine particle containing an ion dissociating group, a fine particle for electronic polarization, a fine particle for a dielectric such as barium titanate), and an insulating oil (for example, silicone oil, hydrocarbon-based). Oil or halogen-based oil). Dispersed electrorheological fluids are classified into a hydrous type containing particles in water and a non-hydrous type containing no water. A homogeneous electrorheological fluid is a fluid made of a substance such as liquid crystal in which molecules are oriented by an electric field and exhibit anisotropy.

FIG. 12 shows a dispersion type electrorheological fluid (FIG. 12).
FIG. 13A is a schematic diagram showing a characteristic difference between (a)) and a homogeneous electrorheological fluid (FIG. 12 (b)). The horizontal axis represents the shear rate dγ / dt, and the vertical axis represents the shear stress τ.
When no electric field is applied (E = 0), both exhibit Newtonian flow (stress proportional to the moving speed (or shear speed) of the object). However, when an electric field is applied (E>
0), the dispersed electrorheological fluid exhibits a Bingham flow in which the straight line of the shear stress moves up in parallel (the stress does not depend on the moving speed (or shear rate) of the object), and the homogeneous electrorheological fluid has the shear stress It shows Newtonian flow in which the gradient (viscosity) of the straight line increases. Dispersed electrorheological fluids include:
For example, there are TH-403 of Fujikura Kasei Co., Ltd. and TX-ER8 of Nippon Shokubai Co., Ltd. As a homogeneous electrorheological fluid, for example, there is ARC01 manufactured by Asahi Kasei Corporation.

FIG. 13 shows the principle of an electrorheological fluid in a dispersion system. (A) shows a state where an electric field is not applied to the electrorheological fluid, and (b) shows a state where an electric field is applied to the electrorheological fluid.
In the state (a) (no voltage is applied),
The dielectric solid fine particles, which are dispersed phase particles, are present separately in oil, which is a dispersion medium. Solid fine particles are very small, having a diameter of, for example, several tens of nm to several μm (the diameter varies greatly depending on the type of dispersed phase). The resistance received when the object is moved in the fluid in the state (a) is substantially equal to the viscous resistance of the oil.

In the state (b) (voltage is applied), the dielectric solid fine particles as the dispersed phase particles are connected to each other in the oil as the dispersion medium to form a chain. The higher the field strength, the greater the number of chains and the longer the average length of the chains. FIG. 13B shows the object in the fluid in the state of FIG.
When the object is moved from left to right (perpendicular to the electric field), the object moves while shearing the chain, and the object receives the shear resistance of the chain. The shear resistance increases as the number of chains increases, and increases as the chain length increases.

FIG. 14 illustrates how shear resistance is generated when an object is moved in an electrorheological fluid. FIG.
In FIG. 3, when the lower electrode (for example, the anode) is fixed and the upper electrode (for example, the cathode) is moved in the direction from left to right in FIG. ). In FIG. 14, the damping force fd (resistance to the movement of the electrode) is a value obtained by multiplying the shear stress by the area of the electrode (Le × B). The shear speed γ is proportional to the moving speed v of the upper electrode and inversely proportional to the width (distance between two electrodes) h of the electrorheological fluid. The relationship between the shear stress and the shear rate γ will be described later (FIGS. 15 and 16).

FIGS. 15 and 16 are characteristic diagrams of the electrorheological fluid TX-ER6 sold by Nippon Shokubai Co., Ltd. (according to data from Nippon Shokubai Co., Ltd.). TX-ER6
Is an electro-rheological fluid of a dispersion system in which a dispersed phase of a sulfonated polymer (having a diameter of about several μm) is dispersed in a dispersion medium of an insulating oil. FIG. 15 is a diagram showing the relationship between the electric field strength applied to the electrorheological fluid at a shear rate of 200 / s and the shear stress. The horizontal axis is the electric field strength (kV / m
m) and the vertical axis is the shear stress (Pa). The solid line shows the relationship between the electric field strength and the shear stress in a direct current (DC) electric field, and the broken line shows the relationship between the electric field strength and the shear stress in an AC 50 Hz AC electric field. FIG. 15 shows that a shear stress almost proportional to the square of the electric field intensity occurs. However, the relationship between the electric field strength and the shear stress differs depending on the product. For example, TH-403 of Fujikura Kasei Co., Ltd.
And in the TX-ER8 of Nippon Shokubai Co., Ltd., the shear stress is almost proportional to the electric field strength. ARC of Asahi Kasei Corporation
01, when the electric field strength is 0 to 1 kV / mm, the shear stress is almost proportional to the electric field strength, and the electric field strength is 1 kV / m.
When m exceeds m, the shear stress gradually increases to a saturation level as the electric field intensity increases. The proportional constants are also different.

In the state where no electric field is applied (FIG. 13A), 1
It produces a shear resistance of 4.5 Pa at a shear rate of 50 / s. 15 at 50 Hz AC and 4 kV / mm electric field
At a shear rate of 0 / s, a shear stress of 2100 Pa is generated, which is about 46 times the stress without an electric field.
It is 0 times. From this, it can be seen that by applying a sufficiently high voltage to the electrorheological fluid, the shear resistance of the chain can be made much larger than that of ordinary oil.

Referring to FIG. FIG. 16A shows AC
4 shows a relationship between a shear rate and a shear stress in a 50 Hz AC electric field. FIG. 16B shows the relationship between shear rate (unit: / s) and shear stress (unit: Pa) in a direct current (DC) electric field. In each case, the dashed line is 1 kV / m
m, an alternate long and short dash line indicates a relationship of 2 kV / mm, an alternate long and two short dashes line indicates a relationship of 3 kV / mm, and a solid line indicates a relationship of 4 kV / mm. The relationship between shear rate and shear stress is also
It differs between products of dispersed electrorheological fluid. For example, TH-403 of Fujikura Kasei Co., Ltd. has a tendency that the shear stress does not change much even if the shear rate changes, and that the shear stress gradually increases as the shear rate increases. TX-ER8 of Nippon Shokubai Co., Ltd. has a tendency that the shear stress does not change much even if the shear rate changes, and the shear stress gradually decreases as the shear rate increases.

The above-described electrorheological fluid can be applied to an optical disk (including CD, DVD, etc.) master recording apparatus. In an optical disc master recording apparatus, a moving stage equipped with a moving optical system including the recording lens is moved at a fast-forward speed of several mm or more per second until the recording lens comes over a recording start point. It is moved at a very low speed of several μm per second. Adopting a moving mechanism of the moving stage using electrorheological fluid for the master recording device, moving the moving stage with low resistance without applying voltage to the electrorheological fluid during fast-forward, and applying voltage during recording to apply damping. Move the moving stage while in the position. Thus, an ideal moving mechanism of the moving stage can be realized.

<< Embodiment 1 >> A first embodiment of the present invention will be described with reference to FIGS. 1 to 5 and FIG. The first embodiment is a moving stage feeder that includes a moving optical system and is included in a DVD master recording device. FIG. 1 is a front view of a moving stage feeder according to an embodiment of the present invention.
FIG. 2 is a plan view of the embodiment of FIG. Reference numeral 1 denotes a guide for a static pressure gas bearing (typically, a static pressure air bearing). Both ends of the guide are supported by a guide support member 2 on a device base. The slide 3 moves along the guide 1. Reference numeral 4 denotes a coil assembly of a linear motor (voice coil motor) which is attached to a lower portion of the slide 3 and moves the slide 3 in a direction perpendicular to the paper surface. Reference numeral 5 denotes a yoke forming a magnetic circuit of the linear motor, which is fixed to the device base. 6 is a permanent magnet fixed to the yoke 5, and 7 is a center yoke. The coil assembly 4 obtains a driving force in a direction perpendicular to the plane of the drawing by applying a current to a coil in a magnetic field of a magnetic circuit composed of the magnet 6, the yoke 5, and the center yoke 7. Reference numeral 8 denotes a position detection scale attached to the side surface of the slide 3, and reference numeral 9 denotes a read head thereof, which is fixed on a yoke 5. The vector of the driving force by which the linear motor drives the moving stage is a plane including a line parallel to the moving direction of the moving stage passing through the center of gravity of the moving stage,
Substantially included in a plane perpendicular to the ground.

The position detection scale 8 has fine stripes at regular intervals. The read head 9 is a read head including a reflection type photo interrupter including a light emitting diode and a light receiving diode, and has a fine striped slit at the same interval as the position detection scale on the front surface of the photo interrupter. The light output from the light emitting diode is reflected by the position detection scale 8, and the light receiving diode inputs the reflected light. When the slide 3 moves, the level of the reflected light input to the light receiving diode changes due to interference between the stripe pattern of the position detection scale 8 and the slit of the reading head 9. Thereby, the reading head 9 detects the amount of movement of the slide 3. The absolute position of the slide 3 can be known by storing the position information of the slide 3 in a nonvolatile storage device and performing calibration of the position information first. The upper plate 10 of the moving stage is fixed on the slide 3.
In a recording apparatus for an optical disk, a moving optical system such as a recording lens and an optical holder is mounted thereon, and moves on a rotating master.

A moving plate 11 made of an insulator is attached to both sides of the upper plate 10 of the moving stage. 2
Each of the moving plates 11 has substantially the same width as the upper plate 10 of the moving stage (the width in FIG. 2). The moving plate 11 is inserted into the container 12. A first electrode 13 serving as an anode and a second electrode 14 serving as a cathode are attached to both inner side walls of the container 12. Therefore, the first electrode and the second electrode are fixed. Container 12
Is filled with an electrorheological fluid (for example, TX-ER8 manufactured by Nippon Shokubai Co., Ltd.). The moving plate 11 moves in the horizontal direction in FIG. 2 with a slight gap of 0.5 mm or less from each of the first electrode 13 and the second electrode 14. The moving plate 11 moves as the moving stage moves. Reference numeral 16 denotes a table for the container 15. First
The electrode 13 and the second electrode 14 generate an electric field in a direction perpendicular to the moving direction of the moving plate 11 (the moving direction of the moving stage). The vector of the braking force (resistance) generated by the moving stages on both sides is a plane including a line parallel to the moving direction of the moving stage passing through the center of gravity of the moving stage,
Substantially symmetric with respect to a plane perpendicular to the ground. Preferably, the container 12 is formed of an insulating plastic or the like. This prevents an electric shock accident when the user touches the outer wall of the container 12. As described above, the moving stage of the feeder according to the present embodiment is held by the hydrostatic air bearing (or the hydrostatic gas bearing using another gas),
It is driven by a voice coil motor and receives a braking force by an electrorheological fluid. Accordingly, basically, the moving part and the fixed part are in contact with each other via the liquid or the gas (excluding the electric connection lines and the like).

It has been discovered that a smooth surface of the moving plate effectively reduces the shear stress. As a result of the study, it was found that a large shear stress can be obtained by making the surface roughness of the moving plate larger than the average value of the diameter of the dispersed particles in the electrorheological fluid. For example, dispersed particles of an electrorheological fluid FKER manufactured by Fujikura Kasei Co., Ltd.
It has a diameter of μm. The surface of the moving plate (moving plate moving in the FKER) is subjected to a treatment such as sand blasting to roughen the surface, so that the peak height of the uneven ridge of the surface measured from the average height of the surface of the moving plate. The average value of the depth of the bottom of the valley or valley is 5 μm or more.

FIG. 3 is an enlarged sectional view showing a part of a moving stage feeding device using an electrorheological fluid (a braking device using an electrorheological fluid having the configuration shown in FIG. 3 is known). The moving plate 11 is attached to the upper plate 10 of the moving stage via an insulator 21. For example, D
In the VD master recording apparatus, a moving optical system including a recording lens is mounted on the upper plate 10. The moving plate 11 (also serving as the second electrode 14) is connected to the cathode of the high-voltage power supply unit 19 by the high-voltage cable 18 (the second electrode is a moving electrode), and is filled with the electrorheological fluid 15. The first electrodes 13 attached to both inner side surfaces of the container 12 are connected to an anode of a power supply unit 19 by a high-voltage cable 18 (the first electrodes are fixed). The moving plate 11 moves in the electrorheological fluid 15 in a direction perpendicular to the paper surface. When the moving plate moves, a DC voltage of, for example, 1 to 4 kV is applied between the moving plate 11 (second electrode 14) and the first electrode 13 by the power supply unit 19. Then, an electric field is generated in the electrorheological fluid (for example, if the distance between the anode and the cathode is 1 mm, an electric field of 1 to 4 kV / mm). As a result, the electrorheological fluid causes induced polarization and forms a particle chain between the moving plate 11 and the container 12. The particle chains generate shear resistance when the moving plate 11 moves, and give a damping effect to the moving direction of the moving stage.

As a result of the experiment, the shear stress of the electrorheological fluid increases as the surface roughness of the moving plate increases. In order to increase the shear stress generated on the side surface of the moving plate 11, the surface of the moving plate 11 is preferably subjected to a treatment such as sandblasting to roughen the surface. More preferably, the moving plate 11 is made of a porous member.
In addition, in order to prevent the flow of the electrorheological fluid from being disturbed due to the movement of the moving plate, it is preferable to sharpen the tip of the moving plate.

With the above-described apparatus, a moving stage with extremely small speed unevenness can be realized. However, in the apparatus shown in FIG. 3, a high-voltage cable must be connected to the moving stage. In an optical disk master recording apparatus (or a stepper or the like) that performs extremely high-precision recording, if the moving stage is moved while the high-voltage cable is connected, slight speed unevenness occurs during the movement of the moving stage. The high-voltage cable is rigid, its load is not constant, and varies depending on the position of the moving stage. As a result, minute unevenness in speed was generated, resulting in uneven track pitch. Similarly, even for devices that require positioning accuracy, such as steppers,
The stiffness of the high-voltage cable affects the stability during stopping.

FIG. 4 is an enlarged sectional view of another container 12. The operation of FIG. 4 will be described. 19 is a high voltage power supply,
The first electrodes 13 and the second
Electrode 14. First electrode 13 and second electrode 13
The electrodes 14 are attached to both inner side surfaces of the container 12, respectively. First electrode 13 and second electrode 14
Are both fixed electrodes. In the present invention, the high voltage cables are fixed together. In the present invention, the first electrode 13 and the second
A voltage of 3 to 4 kV is applied between the electrodes 14, and the electrorheological fluid 15 forms a particle chain between the electrodes. The moving plate 11, which is an insulator, is also dielectrically polarized in the electric field, and a particle chain of the electrorheological fluid 15 is formed between the first electrode 13 and the moving plate 11 and between the second electrode 14 and the moving plate 11. Form. The moving plate 1 placed between the electrodes in such a state
When 1 moves (moves in a direction perpendicular to the plane of the paper of FIG. 4), shearing stress is generated due to the breaking of the particle chains, and a damping action is given to the movement of the slide 3. In the above configuration, since the moving plate 11 does not pull the high-voltage cable, it does not receive the load fluctuation of the high-voltage cable.

The moving plate 11 of the present invention is made of an insulator. When the thickness of the moving plate 11 is thinner, the electric field in the space where the electrorheological fluid exists can be increased (the electric field existing in the space where the moving plate exists does no work). However, in order to move while receiving resistance in an electrorheological fluid, it is necessary to have a rigidity so as not to be twisted even if it is thin. For this purpose, the moving plate 11 according to the invention is made of rigid ceramic, glass or reinforced plastic.

FIG. 5 is an enlarged sectional view of an electrorheological fluid according to another embodiment. In FIG. 5, the moving plate 11 is made of a conductive metal. The metal moving plate has high rigidity. Further, since no electric field exists in the metal, the electric field in the space where the electrorheological fluid exists becomes large, and a large shear stress is generated. First electrode 1
The third and second electrodes 14 are respectively attached to both inner side surfaces of the container 12. The first electrode 13 and the second electrode 14 are both fixed electrodes. However, for example, between the first electrode 13 of the anode and the second electrode 14 of the cathode,
When kV is applied and the moving plate 11 is in the middle between the first electrode 13 and the second electrode 14, the moving plate 11 has a potential of 2 kV. Therefore, if the moving plate 11 and the upper plate 10 of the moving stage are electrically connected to each other, the entire moving stage has a potential of 2 kV. If you touch the moving stage, it is dangerous because you get an electric shock. In addition, there is a possibility that electric discharge occurs in a portion having a low dielectric strength such as a static pressure gas bearing between the slider 3 and the guide 1.

The moving stage (including the upper plate 10, the moving plate 11, the slide 3, the coil assembly 4, the center yoke 7, the position detecting scale 8, etc.) comes in contact with the fixed portion somewhere, so that the moving plate 11 is moved. Is grounded (0 V), the moving plate 11 and the second
Is 0 V, and the potential between the moving plate 11 and the first electrode 13 of the anode is 4 kV. In such a case, since a shear stress acts on only one side of the moving plate 11, a torsional force acts on the moving plate 11, and stable operation is not performed. Therefore, an insulator 21 is inserted between the moving plate 11 and the upper plate 10 of the moving stage to insulate the upper plate 10 of the moving stage from the moving plate 11. Preferably, the moving stage and the ground are connected by a thin and soft conductive wire (FIG. 3 of the conventional example or FIG. 4 of the embodiment).
Alternatively, the present invention can be applied to any of FIGS. ).
Further, preferably, the entire container 12 and the moving plate 11 are covered with a thin plastic plate to prevent an electric shock accident (the present invention can be applied to either FIG. 3 of the conventional example or FIG. 4 or 5 of the embodiment). .).

In another embodiment, the moving plate 11 is made of a porous material having air permeability. In a porous material having air permeability, there is an electrorheological fluid existing therethrough, and when the moving plate 11 moves, the electrorheological flow breaks the particle chains and proceeds. Therefore, a resistance higher than a normal shear stress can be obtained. In still another embodiment, the moving plate 11 has one or more through-holes (holes almost parallel to the traveling direction) that pass from the front end to the rear end.
Having. Reducing the area of the substantial front surface of the moving plate 11 prevents the front surface of the moving plate 11 from pushing the electrorheological fluid forward and causing the electrorheological fluid to overflow from the container 12, and allows the electrorheological fluid to flow from the tip. It is possible to move to the rear side of the moving plate 11 through a hole that passes through the rear end, thereby preventing the electrorheological fluid from overflowing from the container 12. This makes it possible to ensure a smooth flow of the electrorheological fluid, for example,
The gap between the moving plate 11 and the container 12 can be reduced. Therefore, for example, an efficient moving stage feeder can be realized.

In the above description, an electrorheological fluid called a dispersion system in which particles polarized by application of a voltage form a bridge in the direction of an electric field is described. However, when the moving speed of the moving stage is high to some extent, the fluid is formed. The same effect is obtained for an electrorheological fluid called a homogeneous system in which the viscosity increases when molecules and domains are oriented by an electric field. However, when the moving speed at the time of recording is extremely slow, such as the moving stage of an optical disk master recording device,
It is preferred to use a dispersed electrorheological fluid exhibiting Bingham flow. This is because the moving speed is too slow and sufficient resistance cannot be generated by a homogeneous electrorheological fluid exhibiting Newtonian flow.

A case where the present invention is used for a moving stage feeder of an optical disk master recording apparatus will be described. Usually, a glass disk having a diameter of about 200 mm is used as the master of the optical disk.
1 = about 20mm (inner circumference) to r2 = about 65mm (outer circumference)
It is. The start of recording often starts from the inner circumference.
Therefore, the recording head first moves to the recording start position in the fast-forward mode, performs recording at a low speed from that position, and returns to the standby position in the fast-forward mode again after the recording is completed.
In the apparatus of the present invention, in the fast-forward mode, no voltage is applied to the electrodes, smooth feeding with less resistance is realized, and a high voltage is applied to the electrodes only in the low-speed recording mode, whereby a strong damping effect can be obtained.

FIG. 11 is a block diagram of a control device of the feeder of the moving stage according to the present embodiment. v0 is the target speed,
x is the current position of the moving stage, v = dx / dt is the moving speed of the moving stage, k1 is the proportional constant of the proportional control device, k
2 is an integral constant of the integral control device, fd (v) is a transfer function of the braking device (a resistance is generated by applying a voltage to the electrorheological fluid), and g (x, t) is a position. And disturbance as a function of time (including the resistance of the hydrostatic gas bearing, etc.), m is the mass of the moving stage, (dv / dt)
Is the acceleration of the moving stage. The subtractor 30 receives the target speed v0 and the actual speed v, and outputs a difference (v0−v). The proportional control device 31 receives the difference (v0−v) and outputs k1 (v0−v). Integral controller 32
Inputs the difference (v0-v) and outputs Σk2 (v0-v). The adder 34 outputs the output signal k1 (v0−v) of the proportional controller 31 and the output signal Σk of the integral controller 32.
2 (v0−v) and the resistance f generated by the braking device
d (v) and the disturbance g (x, t) are subtracted. The force F applied to the moving stage can be expressed by the following equation (1). F = k1 (v0−v) + Σk2 (v0−v) −fd (v) −g (x, t) = m · (dv / dt) (1)

When fd (v) does not exist, the optimum values of k1 and k2 are small.
Since it is necessary to offset fd (v) by 1 (v0-v) or the like, the optimal values of k1 and k2 become large. The position detection device 35 outputs the position x of the moving stage. The differentiator 36 inputs the position x, and differentiates the position (velocity) v = d
Output x / dt. Braking device (including electrorheological fluid)
37 inputs the actual speed v and outputs the resistance fd (v). The speed v is measured, for example, by counting the number of output pulses of the position detection scale that the reading head 9 inputs within a certain time. In another embodiment, speed is measured by measuring the time between pulses of the position detection scale (eg, counting the number of other very fast pulses occurring between pulses of the position detection scale). Is measured. In the above equation (1), considering the influence of a minute disturbance generated in a stable state, the influence on the integral control system is very small, and the resistance of the braking device does not change. Therefore, ΔF = k1 · Δv−Δg ( t) (2) If ΔF = 0, Δv = Δg (t) / k1 Since k1 is large, the speed unevenness Δv based on Δg (t) is small.

In a CLV optical disk such as a CD or DVD, the moving speed of the moving stage during recording differs between the inner and outer circumferences of the disk. At the inner circumference (radius r1), the moving speed v1 of the moving stage is fast, and at the outer circumference (radius r2).
Then, the moving speed v1 of the moving stage is slow. Since the area on the disk scanned by the laser beam per unit time is constant, the relational expression can be expressed by the following expression (3). r1 · v1 = r2 · v2 (r1 <r2) (3) In order to minimize the speed unevenness of the moving stage from the outer circumference to the inner circumference of the optical disc, from the inner circumference to the outer circumference of the optical disc, (fluid viscosity) × (movement) It is preferable to keep (speed) = constant (4).

As shown in FIG. 16, when the moving speed of the moving stage (that is, the shearing speed of the moving plate) changes, the shear stress of the electrorheological fluid changes when the electric field strength is constant. In the moving stage feeder of the optical disk master recording device, the transfer function fd (v) of the braking device 33 is determined to be a function of v, and the expression (4) is determined at an arbitrary position of the moving stage. The transfer function fd (v) is determined by the moving speed v of the moving plate and the shear stress of the electrorheological fluid at the moving speed (for example, FIG.
6) and the relationship between the electric field and the shear stress (for example, FIG. 11). Specifically, for example, in a braking device using TX-ER6 manufactured by Nippon Shokubai Co., Ltd.,
Fd at the position where the moving speed of the moving stage is fast
By increasing the value of (v), it is possible to accurately and stably control the master recording apparatus for the CLV optical disk. Since the above-mentioned electro-rheological fluid of Fujikura Kasei Co., Ltd. has a tendency for the shear stress to gradually increase as the shear rate increases, the value of fd (v) is also reduced at a position where the moving speed of the moving stage is high. C
It is possible to accurately and stably control the master recording device of the LV optical disk.

The braking device 37 changes the voltage applied between the two electrodes of the electrorheological fluid according to the position of the moving stage. The moving speed of the moving stage is 5 μm / sec to 10 μm
/ sec, and the distance between the electrodes is, for example, 1 mm. The applied voltage is changed from 1.0 kV to 4.0 kV according to the speed (in the case where the electrode shown in FIG. 3 is provided). In the feeding device having the electrodes shown in FIG.
m, and the distance between the moving plate and each electrode is 0.5 mm. The applied voltage is 1 kV or more depending on the speed.
Change to 4 kV.

By applying an electric field to the electrorheological fluid according to the moving speed of the moving stage, the movement of the moving stage is suppressed. As shown in FIG. 13, the electrorheological fluid is a colloid solution in which particles having an electric polarization property are dispersed in an insulating fluid. When an electric field is applied to the electrorheological fluid, the particles are polarized, and the apparent viscosity of the fluid changes by forming a chain of particles called clusters. Note that the gain k2 of the integral control device 32 can be increased to control the moving speed of the moving stage while maintaining fd (v) at a constant value fd0.

In another embodiment, a load near the limit at which the voice coil motor can drive the moving stage is always applied. This minimizes uneven speed. In this case, if the load (resistance) fd (v) applied to the moving stage is not reduced when the target moving speed of the moving stage is increased, even if the voice coil motor exhibits the maximum driving force, the target is not reduced. Do not reach speed. Therefore, contrary to the above embodiment, when the target moving speed increases, the load fd (v) applied to the moving stage is reduced. This allows
Always minimize speed fluctuations.

FIG. 19 shows another embodiment of the control device of the moving stage feeder of the present invention using an observer.
FIG. 19 is represented by a Laplace transform equation. The control device is
The position target value Xc and the actual position X read by the position detection scale 8 are input. The target speed Vc = Kpp · (Xc−X)
X). Difference between target speed and actual speed V (Vc-V)
Is calculated.

A proportional component Kvp · (Vc−V) obtained by multiplying the difference (Vc−V) by a proportional gain Kvp, and an integral gain Kv
Kvi / s integral component multiplied by iΣKvi · (Vc−V)
Is calculated, and the proportional component and the integral component are added. The output signal of the observer is added to the addition result. The result of adding the output signals of the observer signal passes through a low-pass filter. The output signal of the low-pass filter is input to the drive stage of the linear motor (the block displaying the thrust constant Kf) and to the observer. A linear motor drives the moving stage.
The moving stage is represented by 1 / (Ms + C). M is the mass of the moving stage, and C is the stress of the electrorheological fluid.
Also, a disturbance FL is added. The moving stage driven in this way moves at the actual speed V. The moving stage is located at the position X over time.

Kf written in the lower part of FIG. 19 and MS + C
, A subtractor for subtracting the MS + C output signal from the Kf output signal, Gobs (s), and 1 / Kf constitute an observer. The observer receives the output signal of the low-pass filter and multiplies it by the thrust constant of the linear motor to obtain a thrust value. The actual speed V is input, and the inertia force Ms and the stress C of the electrorheological fluid are estimated from Ms + C. The inertial force and the stress C of the electrorheological fluid are subtracted from the thrust of the linear motor. The result obtained passes through the block of the transfer function Gobs (s),
The result is multiplied by 1 / Kf and input to the subtractor. In this embodiment, C is particularly kept constant. Since the shear stress of the electrorheological fluid changes according to the moving speed of the moving plate as described above, the output voltage of the power supply unit 19 is controlled so that the shear stress becomes constant regardless of the moving speed of the moving plate. Alternatively, when the output voltage of the power supply unit 19 is kept constant, the container 12 takes the configuration of FIG. 7 or FIG. 8 (FIGS. 7 and 8), whereby C is kept constant.

FIG. 18 shows a part of a feeding device for short-circuiting two electrodes after the power switch is turned off to discharge the electric charges accumulated in the electrodes. The feeder shown in FIG. 18 is an improvement of the feeder shown in FIG. 3, and the same parts are given the same numbers. A description overlapping with that of FIG. 3 will not be given. The feeding device of FIG. 18 is obtained by adding a power switch 51 for high voltage to the feeding device of FIG. Power switch 5
1 is a break-before-make switch (while the movable contact (C contact) is moving from the ON (conducting) contact to the OFF (cutoff) contact (and is moving in the opposite direction);
The switch always has a period during which the movable contact does not conduct both the ON contact and the OFF contact. When the movable contact of the power switch 51 is turned on, the power supply 19 supplies power to the first electrode 13 and the second electrode 14. Power switch 51
When the movable contact is turned off, the power supply from the power supply unit 19 to the electrodes is cut off, and the first electrode 13 and the second electrode 1 are turned off.
4 are short-circuited via the resistor 52. The resistor 52 is
Prevents excessive current from flowing during a short circuit. As a result, the electric charges accumulated in the first electrode 13 and the second electrode 14 are discharged.

In another embodiment, a high withstand voltage high resistance is connected between the first electrode 13 and the second electrode 14. The high withstand voltage high resistance consumes useless power during the operation of the feeding device, but after the power switch is turned off, the electric charges accumulated in the two electrodes are discharged through the high resistance. With the above method, electric shock can be prevented.

Further, by changing the voltage applied to the electrorheological fluid to an AC voltage (AC voltage), the danger in the event of electric shock is reduced (generally, a person who receives an electric shock from a DC voltage rather than an AC voltage) Is said to be dangerous for the human body.) In addition, the moving stage is hardly charged. Further, the viscosity of the electrorheological fluid can be changed by applying an AC voltage to the electrode and changing the frequency of the AC voltage. << Embodiment 2 >> A second embodiment of the present invention will be described with reference to FIG. The second embodiment is a moving stage feeder (or a stepper moving stage feeder) equipped with a moving optical system included in a DVD master recording apparatus. FIG.
(A) of the moving stage feeder according to the second embodiment
It is a bottom sectional view and (b) longitudinal sectional view. In FIG.
The same parts as those in the first embodiment are denoted by the same reference numerals as those in FIG. Reference numerals 40 and 41 are guides of a static pressure gas bearing (typically, a static pressure air bearing). The position of the moving stage in the horizontal direction in FIG. 6 is regulated by the guide 41, and the position of the moving stage in the vertical direction in FIG. The guides 40 and 41 may be hydrostatic bearings or precision linear guides.

The moving stage moves along guides 40 and 41. Reference numeral 4 denotes a coil assembly of a linear motor (voice coil motor) which is attached to a lower portion of the upper plate 10 of the moving stage and moves the moving stage in the vertical direction in the sectional view of FIG. Reference numeral 5 denotes a yoke forming a magnetic circuit of the linear motor, which is fixed to the device base. 6 is a permanent magnet fixed to the yoke 5, and 7 is a center yoke. The coil assembly 4 obtains a driving force in a direction perpendicular to the plane of the drawing by applying a current to a coil in a magnetic field of a magnetic circuit composed of the magnet 6, the yoke 5, and the center yoke 7. The vector of the driving force for driving the moving stage by the linear motor is a plane including a line parallel to the moving direction of the moving stage passing through the center of gravity of the moving stage and substantially included in a plane perpendicular to the ground. Although not shown in FIG. 6, the feeder of the second embodiment has a position detection scale attached to the lower surface of the upper plate 10 of the moving stage and its read head attached to the yoke 5. The configuration and operation of the position detection scale and its reading head are the same as in the first embodiment. In an optical disk recording apparatus, a moving optical system such as a recording lens or an optical holder is mounted on an upper plate 10 of a moving stage, and the recording lens moves on a rotating master.

A moving plate 11 made of an insulator is mounted on both sides of the upper plate 10 of the moving stage. The moving plate 11 is inserted in the container. A first electrode 13 serving as an anode and a second electrode 14 serving as a cathode are attached to the inner side walls of both sides of the container, and an electrorheological fluid (for example, TX-ER8 manufactured by Nippon Shokubai Co., Ltd.) is provided therein.
5 is inserted. The moving plate 11 includes a first electrode 13
6 with a slight gap of 0.5 mm or less from each of the second electrodes 14 and in the vertical direction in the cross-sectional view of FIG. The moving plate 11 moves as the moving stage moves. The first electrode 13 and the second electrode 14 generate an electric field in a direction perpendicular to the moving direction of the moving plate 11 (the moving direction of the moving stage). The connecting pipe (pipe) 39 connects the two containers, and the electrorheological fluid 15 fills the two containers and the connecting pipe 39. Large U-shaped containers (plan view) can also be used. In this case, the portions corresponding to the vertical lines of the U-shaped container are the first container and the second container, and a guide and a slide movable along the guide are arranged inside the U-shaped container. The vector of the braking force (resistance) generated by the moving plates 11 on both sides is a plane including a line parallel to the moving direction of the moving stage that passes through the center of gravity of the moving stage and is perpendicular to a plane perpendicular to the ground. Substantially symmetric.

In the above embodiment, the two electrodes for applying an electric field to the electrorheological fluid were both fixed electrodes.
In another embodiment, one of the two electrodes for applying an electric field to the electrorheological fluid is a fixed electrode and the other electrode is a fixed electrode.
The electrodes are moving electrodes. For example, as shown in FIG. 3, the first electrode is a moving plate 11 made of a conductor (an insulator is inserted between the upper plate 10 and the moving plate 11 of the moving stage). The second electrode is an electrode attached to both inner sides of the container. The potentials of the fixed electrodes provided on both sides of the moving electrode may be different, but are generally the same.

The controller of the moving stage feeder of the second embodiment is the same as that of the first embodiment (see FIG. 11). The moving speed of the moving stage is 5 μm / sec to 10 μm
/ sec, and the distance between the electrodes is, for example, 1 mm. The applied voltage is changed from 1.0 kV to 4.0 kV according to the speed (in the case where the electrode shown in FIG. 3 is provided). In the feeding device having the electrodes shown in FIG.
m, and the distance between the moving plate and each electrode is 0.
5 mm. The applied voltage is 1 kV to 4 k depending on the speed.
V.

<< Embodiment 3 >> A third embodiment of the present invention is shown in FIG.
This will be described with reference to FIG. FIG. 7 is a (a) bottom view and (b) an enlarged cross-sectional view of an electrorheological fluid portion of a feeder using an electrorheological fluid according to a third embodiment. The third embodiment is based on D
This is a moving stage feeder that includes a moving optical system and is included in a VD master recording device. The basic configuration of the third embodiment is the same as that of the second embodiment, and elements different from each other are shown in FIG. 7 (many elements common to both are not described). In the third embodiment, the width of the container 12 containing the electrorheological fluid 15 changes along the moving direction of the moving plate 11 (in the plan view of FIG. 7, the container 12 has a tapered shape). ). The distance d between the first electrode 13 and the second electrode 14 attached to both inner side surfaces of the container 12 also changes.

The power supply section 19 applies a constant voltage V (for example, DC 1 kV) to the first electrode 13 and the second electrode 14. As the moving plate 11 moves (depending on the position of the moving stage in the moving direction), the distance between the first electrode 13 and the second electrode 14 changes, so that the electric field strength E = V / d changes, and Fluid shear stress changes. Thereby, an optimum damping resistance (shear stress) can be generated according to the position of the moving stage. In a DVD master recording device or the like, the moving stage feeder of the third embodiment changes the damping resistance according to the distance between the position of the recording lens and the center of the master.

Although an expensive control circuit is required to control a high voltage of 1 kV or more, the above-described configuration allows the electro-rheological fluid to generate an electric field that changes according to the position of the moving stage without extra cost. Can be applied. However, in the third embodiment, the applied voltage can be further changed. By implementing this in conjunction with the configuration of the third embodiment, the range of change in the applied voltage can be reduced.

In FIG. 7, one row of the electrorheological fluids 15 is arranged on each side of the drive portion (linear motor), but one row may be arranged near the center. When the electrorheological fluid 15 is provided on both sides of the driving portion (linear motor), a connecting pipe 39 connecting the liquids on both sides may be provided in order to keep the liquid level constant. In the third embodiment, the first electrode 13 and the second electrode 14 are both fixed electrodes.
For example, the first electrode 13 may be a fixed electrode, and the second electrode 14 may be a moving electrode. Although the third embodiment applies a constant voltage between the electrodes, a changing voltage may be applied.

<< Embodiment 4 >> A fourth embodiment of the present invention is shown in FIG.
This will be described with reference to FIG. FIG. 8A is a side sectional view of a feeder using an electrorheological fluid according to a fourth embodiment, and FIG.
It is an expanded sectional view of an electrorheological fluid part. The fourth embodiment is a moving stage feeder that includes a moving optical system and is included in a DVD master recording apparatus. The basic configuration of the fourth embodiment is the same as that of the second embodiment, and FIG. 8 shows elements that differ from each other (many elements common to both are not shown). In the fourth embodiment, as in FIG. 3, the first electrode 13 is a fixed electrode, and the second electrode 14 is a moving electrode (also serving as the moving plate 11). The width of the first electrode 13 attached to both sides of the inside of the container 12 containing the electrorheological fluid 15 is
1 (in the side view of FIG. 8, the two first electrodes 13 attached to both sides of the container 12 have a triangular shape). Moving plate 11
A portion of the side surface of the (second electrode 14) where the moving plate 11 faces the first electrode 13 (an overlapping portion).
Only the shear stress τ of the electrorheological fluid 15 acts. This is because an electric field exists substantially only in a portion where both electrodes face each other.

The power supply 19 applies a constant voltage V (for example, DC 1 kV) to the first electrode 13 and the second electrode 14. Assuming that the distance between the first electrode 13 and the second electrode 14 is d, an electric field E = V / d is applied to the electrorheological fluid.
Based on the electric field E, a shear stress τ acting on the moving plate 11 having a unit area (limited to a portion where an electric field exists) is determined. As the moving plate 11 moves (depending on the position of the moving stage in the moving direction), the first electrode 13 and the second electrode 13 move.
Since the area S of the portion facing the electrode 14 changes,
The resistance (damping force) fd = τ × S changes, and the shear stress of the electrorheological fluid changes. Thereby, an optimum damping resistance (shear stress) can be generated according to the position of the moving stage. In a DVD master recording apparatus or the like, the moving stage feeder of the fourth embodiment changes the damping resistance according to the distance between the position of the recording lens and the center of the master.

Although an expensive control circuit is required to control a high voltage of 1 kV or more, the above-described configuration allows the electric field which changes according to the position of the moving stage to be applied to the electrorheological fluid without any extra cost. Can be applied. However, in the fourth embodiment, the applied voltage can be further changed. By implementing this in combination with the configuration of the fourth embodiment, the range of change in the applied voltage can be reduced.

In FIG. 8, the fixed electrodes 13 (13 and 14)
Is changed, the area of the movable electrode 14 may be changed. For example, in the side view of FIG. 8, the moving plate 11 (also serving as the second electrode 14) has a triangular shape. The fixed electrode 13 has a rectangular shape, and the width of the fixed electrode 13 is smaller than the width of the moving plate 11. (FIG. 8
Side view). Accordingly, as the moving plate 11 moves (in accordance with the position of the moving stage in the moving direction), the area of the portion where the fixed electrode 13 and the moving plate 11 (second electrode 14) overlap changes. The shape of both the left and right electrodes and the moving electrode may be changed to an arbitrary shape.

In FIG. 8, the electrorheological fluids 15 are arranged in one row on both sides of the driving portion (linear motor), but may be arranged in one row near the center. When the electrorheological fluid 15 is provided on both sides of the driving part (linear motor), a connecting pipe 39 for connecting the liquids on both sides may be provided in order to keep the liquid surface level the same on the left and right. The fourth embodiment is the first embodiment.
Although the electrode 13 is a fixed electrode and the second electrode 14 is a moving electrode, for example, the first electrode 13 and the second electrode 14
Are fixed electrodes (for example, a first electrode 13 and a second electrode 14 each having a triangular shape as shown in the side view of FIG. 8 are attached to each of a left side surface and a right side surface inside the container 12). It may be. In the fourth embodiment, a constant voltage is applied between the electrodes, but a changing voltage (for example, an AC voltage) may be applied. The left and right first electrodes 13 attached to both inner side surfaces of the container 12 are generally at the same potential, but need not be at the same potential.

<< Embodiment 5 >> A fifth embodiment of the present invention is shown in FIG.
This will be described with reference to FIG. Note that the second electrode in FIG. 7 is a fixed electrode, and the second electrode in FIG. 8 is a moving electrode.
In the fifth embodiment, since the second electrode is a fixed electrode, the second electrode 14 in FIG. 8 is replaced with a fixed electrode. ). The fifth embodiment is a moving stage feeder equipped with a moving optical system, which is included in a DVD master recording apparatus. The basic configuration of the fifth embodiment is the same as that of the second embodiment, and the elements different from each other are shown in FIGS. 7 and 8 (many elements common to both are not described). ).

The power supply section 19 applies a constant voltage V (for example, DC 1 kV) to the first electrode 13 and the second electrode 14. In the fifth embodiment, the width of the container 12 containing the electrorheological fluid 15 changes along the moving direction of the moving plate 11 (in the plan view of FIG. 7, the container 12 has a tapered shape). ), The widths of the first electrode 13 and the second electrode 14 attached to both sides inside the container 12 containing the electrorheological fluid 15 change along the moving direction of the moving plate 11 (FIG. 8). In the side view, two first electrodes 13 attached to both side surfaces of the container 12 are shown.
Has a triangular shape. ). As the moving plate 11 moves (depending on the position of the moving stage in the moving direction), the distance between the first electrode 13 and the second electrode 14 changes, so that the shear stress τ changes, and at the same time, the first electrode 13 changes. The resistance (damping force) fd = τ × S changes due to the change in the area S of the portion where the electrode and the second electrode 14 face each other, and the shear stress of the electrorheological fluid changes. Thereby, an optimum damping resistance (shear stress) can be generated according to the position of the moving stage. In a DVD master recording device or the like, the moving stage feeder of the fifth embodiment changes the damping resistance according to the distance between the position of the recording lens and the center of the master.

In FIG. 7, the electrorheological fluids 15 are arranged in a row on both sides of the driving portion (linear motor), but may be arranged in a row near the center. When the electrorheological fluid 15 is provided on both sides of the driving portion (linear motor), a connecting pipe 39 connecting the liquids on both sides may be provided in order to keep the liquid level constant. In the fifth embodiment, the first electrode 13 and the second electrode 14 are both fixed electrodes.
For example, the first electrode 13 may be a fixed electrode, and the second electrode 14 may be a moving electrode. In the fifth embodiment, a constant voltage is applied between the electrodes, but a changing voltage may be applied. In addition, various variations as described in the third embodiment and the fourth embodiment are possible.

<< Embodiment 6 >> A sixth embodiment of the present invention is shown in FIG.
This will be described with reference to FIG. The sixth embodiment is a DVD
And a moving stage feeder equipped with a moving optical system, which is included in the master recording apparatus. FIG. 9 is a front view of the moving stage feeder according to the second embodiment, and FIG. 10 is a plan view of the moving stage feeder according to the second embodiment. FIG.
10 and FIG. 10, parts that are the same as those in the first embodiment and the like are given the same reference numerals as in FIG. 1 and the like. Reference numerals 40 and 41 are guides of a static pressure gas bearing (typically, a static pressure air bearing). The position of the moving stage in the horizontal direction in FIG. 9 is regulated by the guide 41, and the position of the moving stage in the vertical direction in FIG. The arrow in FIG. 9 indicates the direction in which the static pressure is applied, and the tip of the arrow indicates the boundary between the moving stage (movable part) and other fixed parts. The guides 40 and 41 may be hydrostatic bearings or precision linear guides.

The moving stage moves along the guides 40 and 41. Reference numeral 4 denotes a coil assembly of a linear motor (voice coil motor) which is attached to a lower portion of the upper plate 10 of the moving stage and moves the moving stage in the vertical direction in the sectional view of FIG. Reference numeral 5 denotes a yoke forming a magnetic circuit of the linear motor, which is fixed to the device base. 6 is a permanent magnet fixed to the yoke 5, and 7 is a center yoke. The coil assembly 4 obtains a driving force in a direction perpendicular to the plane of the drawing by applying a current to a coil in a magnetic field of a magnetic circuit composed of the magnet 6, the yoke 5, and the center yoke 7. The vector of the driving force generated by the coil assembly 4 and the like is included in a plane perpendicular to the ground (also perpendicular to the plane of the upper plate 10), including the center of gravity of the moving stage. It has a position detection scale 8 attached to the lower surface of the upper plate 10 of the moving stage, and its read head 9 attached to the yoke 5. The configuration and operation of the position detection scale and its reading head are the same as in the first embodiment. In an optical disk recording apparatus, a moving optical system such as a recording lens or an optical holder is provided with an upper plate 1 of a moving stage.
0, and the recording lens moves on the rotating master 47.

The arm 46 has two moving plates 11 at one end, and the other end is attached to a moving stage. The arm 46 transmits the shear stress of the electrorheological fluid applied to the moving plate to the moving stage. The vector of the shear force of the electrorheological fluid transmitted to the moving stage by the arm 46 is included in a plane perpendicular to the ground (also perpendicular to the plane of the upper plate 10), including the center of gravity of the moving stage. Each of the two moving plates 11 is inserted into a container. A first electrode 13 serving as an anode and a second electrode 1 serving as a cathode are provided on both inner side walls of the container.
4, and an electrorheological fluid (for example, TX-ER8 manufactured by Nippon Shokubai Co., Ltd.) 15 is put in the device.
The moving plate 11 includes a first electrode 13 and a second electrode 1.
4 is moved in the vertical direction in the cross-sectional view of FIG. The moving plate 11 moves as the moving stage moves. The first electrode 13 and the second electrode 14 generate an electric field in a direction perpendicular to the moving direction of the moving plate 11 (the moving direction of the moving stage).

In FIG. 9, the vector of the driving force generated by the voice coil motor and the vector of the resistance generated by the braking device using the electrorheological fluid are each a plane perpendicular to the ground passing through the center of gravity of the moving stage (FIG. 9). Is also a plane perpendicular to the plane of the paper.) Therefore, the vector of the driving force generated by the voice coil motor and the vector of the resistance generated by the braking device using the electrorheological fluid accelerate or decelerate the moving stage, but do not rotate the moving stage (rotation). No moment is generated.)

Iron bars 43 are attached to both sides of the upper plate 10 of the moving stage. Also, pedestals 45 are provided on both sides of the fixed portion of the feeder, and an electromagnetic magnet (coil and iron core) 44 is provided on each pedestal 45. Iron bar 43 and electromagnetic magnet 44
Are opposed to each other in the vertical direction with a slight gap. By passing a current through the coil of the electromagnetic magnet, the electromagnetic magnet 44 attracts the iron bar 43. In FIG. 9, the moving stage moves in a direction perpendicular to the plane of FIG. 9 with both ends of the upper plate 10 of the moving stage being applied downward (in a direction perpendicular to the ground) in the figure. Thereby, vibration of the upper plate of the moving stage can be suppressed. The current flowing through the coil of the electromagnetic magnet is
It is constant. Preferably, by changing the current flowing through the coil of the electromagnetic magnet according to the position x of the moving stage or the moving speed v of the moving stage, a damping effect of optimally suppressing vibration of the upper plate of the moving stage is obtained. The electromagnetic magnet 44 and the iron bar 43 constitute a magnetic force generator. The force vectors generated by the magnetic force generators on both sides are planes including a line parallel to the moving direction of the moving stage passing through the center of gravity of the moving stage, and are substantially symmetric with respect to a plane perpendicular to the ground. It is.

In another embodiment, an iron bar is provided on the table 45, and electromagnetic magnets (coils and iron cores) are provided on both sides of the upper plate 10 of the moving stage. In this case, since the connection line of the coil of the electromagnetic magnet is connected to the movable part, the movement of the moving stage prevents the connection line from causing disturbance. A thin and soft wire can be used as the connection wire of the coil of the electromagnetic magnet.

The controller of the moving stage feeder of the sixth embodiment is the same as that of the first embodiment (see FIG. 11). The moving speed of the moving stage is 5 μm / sec to 10 μm
/ sec, and the distance between the electrodes is, for example, 1 mm. The applied voltage is changed from 1.0 kV to 4.0 kV according to the speed (in the case where the electrode shown in FIG. 3 is provided). In the feeding device having the electrodes shown in FIG.
m, and the distance between the moving plate and each electrode is 0.5 mm. The applied voltage is 1 kV or more depending on the speed.
Change to 4 kV.

[Description of braking device using magnetic fluid (FIG. 2)
0)] Although the above description uses an electrorheological fluid, a magnetic fluid may be used instead of the electrorheological fluid. FIG. 20 shows a schematic configuration of a braking device in which a magnetic fluid is placed in the container 12 instead of the electrorheological fluid. The magnetic fluid is
Applying a magnetic field increases the shearing capacity. For example, a magnetic fluid (MRF magnetic rheological sold by Lord Corporation in the United States)
al Fluid (trade name)) MRF-132L
D and the like. In FIG. 20, a moving plate 11 of a moving stage 10 moves in a container 12 filled with a magnetic fluid 201.

The core 202 having the winding 203 has a small gap, and the moving plate and the magnetic fluid are sandwiched in the small gap. Container 12 may also be in the gap. Or, the core 202 is the container 1
2 and facing the gap of the core 202 may form part of the inner wall of the container. The latter is preferable because the distance of the gap can be reduced and a high magnetic field can be obtained. The core 202 and the gap form a magnetic circuit. The core 202 is formed of a material having a high magnetic permeability (eg, ferrite). Power supply unit 20
4 passes a current through the winding 203. As a result, a magnetic flux flows through the magnetic circuit (the core 202 and the gap), and a strong magnetic field is formed in the gap. Magnetic fluid 20 placed in strong magnetic field
When the moving plate 11 moves in the inside 1, a high shear stress is generated. Thereby, the device of FIG. 20 functions as a braking device. By applying the braking device of FIG. 20 to the above embodiment, the same effects as in the above embodiment can be obtained.

For example, the gap planes of the core 202 are typically parallel to each other, but by making them non-parallel, the magnetic field strength at each point in the gap is changed, whereby the shear at each point is changed. The stress can be changed. or,
For example, the movable plate 11 made of ferrite having a high magnetic permeability and having a triangular shape is moved. If the area of the moving plate existing in the gap is large, the magnetic resistance becomes small and the magnetic field becomes strong. Thereby, the shear stress can be changed depending on the position of the moving plate. Although an expensive control circuit is required to control the large current flowing through the winding 203, the power supply unit 20 that outputs a constant power supply current
According to the above configuration using No. 4, it is possible to apply a magnetic field that changes according to the position of the moving stage to the magnetic fluid without incurring any special cost. However, the power supply unit 20
4 can also change the output current. By implementing this in combination with the configuration of the above embodiment, the range of change in the output current of the power supply unit 204 can be reduced.

[0097]

According to the present invention, by variably controlling the voltage applied to the electrorheological fluid, the swinging motion of the moving stage in the moving direction and the direction perpendicular to the moving direction is suppressed, and the track pitch unevenness is reduced. An advantageous effect that a feeder for the moving stage can be realized is obtained.

In the present invention, the distance between the electrodes for applying an electric field to the electrorheological fluid changes according to the position of the moving stage in the moving direction. For example, a constant voltage V between the electrodes
Is applied, the damping effect by the electrorheological fluid can be changed according to the position of the moving stage.
Also, in the present invention, the area of the part where the electrodes for applying the electric field to the electrorheological fluid oppose each other (the area where the electrodes overlap) changes according to the position of the moving stage in the moving direction. In the present invention, the distance between the electrodes for applying an electric field to the electrorheological fluid and the area of the part where the electrodes face each other (the area where the electrodes overlap) change according to the position of the moving stage in the moving direction. . According to the present invention, the electric field applied to the electrorheological fluid is variably controlled according to the position of the moving stage with respect to the container, so that the moving direction, the rocking motion of the moving stage in a direction perpendicular to the moving direction is suppressed, An advantageous effect is obtained that a feeder for a moving stage with small pitch unevenness can be realized. or,
According to the present invention, an advantageous effect is obtained that an inexpensive moving stage feeder that uses a power supply unit that outputs a constant voltage or a voltage in a small change range can be realized.

The feeder of the present invention has an electrorheological fluid braking device (including a container, an electrorheological fluid, etc.) at symmetrical positions on both sides of the center line (including the center of gravity) of the moving stage. By disposing the electrorheological fluid on both sides of the moving stage, it is possible to prevent imbalance in vibration of the moving stage. According to the present invention, by imparting a balanced shear stress (resistance) to the moving stage, the oscillating motion of the moving stage in the moving direction and the direction perpendicular to the moving direction is suppressed, and the moving stage having a small track pitch unevenness. The advantageous effect that the feeder of this type can be realized is obtained.

In the feeder of the present invention, containers on both sides are connected by pipes or the like so that the liquid level of the electrorheological fluid provided on both sides of the moving stage is constant. This allows
Prevents the liquid level from becoming unbalanced. ADVANTAGE OF THE INVENTION According to this invention, the advantageous effect that it can implement | achieve the feed apparatus of the moving stage which does not deteriorate with time is obtained. Further, according to the present invention, there is obtained an advantageous effect that it is possible to realize a moving stage feeder which does not require the balance adjustment of the amount of the electrorheological fluid put in the two containers.

In the feeder of the present invention, both the driving force and the braking force (resistance) of the moving stage are on a vertical plane including the center of gravity of the moving stage. According to the present invention, by providing a driving force and a shear stress (resistance) without unbalance, the swinging motion of the moving stage in the moving direction and the direction perpendicular to the moving direction is suppressed, and the moving stage with small track pitch unevenness is provided. The advantageous effect that the feeder of this type can be realized is obtained. Further, according to the present invention, there is obtained an advantageous effect that it is possible to realize a moving stage feeder that does not require (or is easy to adjust) the balance between the driving force and the shearing stress.

The feeder of the present invention further has magnetic force generators at symmetrical positions on both sides of the center line (including the center of gravity) of the moving stage. According to the present invention, there is obtained an advantageous effect that the swinging motion of the moving stage in the moving direction and the direction perpendicular to the moving direction is suppressed, and a feeder for the moving stage with small track pitch unevenness can be realized.

According to the present invention, there is obtained an advantageous effect that an efficient moving stage feeder can be realized.
According to the present invention, when the power supply is cut off, the electric charge accumulated in the electrodes is always short-circuited and discharged, so that an advantageous effect of realizing a safe moving stage feeder can be obtained.

In the present invention, a magnetic fluid is used in place of the electrorheological fluid. According to the present invention, the same effects as those described with respect to the above-described invention can be obtained. Further, according to the present invention, there is obtained an advantageous effect that danger such as electric shock is small.

[Brief description of the drawings]

FIG. 1 is a front view of a moving stage feeder according to a first embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a schematic enlarged sectional view of a part (an electrorheological fluid part) of FIG. 1;

FIG. 4 is a schematic enlarged sectional view of a part (an electrorheological fluid part) of another embodiment of the present invention.

FIG. 5 is a schematic enlarged sectional view of a part (an electrorheological fluid part) of another embodiment of the present invention.

FIG. 6 is a schematic (a) bottom sectional view and (b) of a feeder using an electrorheological fluid according to a second embodiment of the present invention.
Longitudinal section

FIG. 7 is a schematic (a) bottom sectional view and (b) of a feeder using an electrorheological fluid according to a third embodiment of the present invention.
Enlarged sectional view of a part (electrorheological fluid part)

FIG. 8 is a schematic (a) side sectional view and (b) of a feeder using an electrorheological fluid according to a fourth embodiment of the present invention.
Enlarged sectional view of a part (electrorheological fluid part)

FIG. 9 is a front view of a moving stage feeder according to a sixth embodiment of the present invention.

FIG. 10 is a plan view of FIG. 11;

FIG. 11 is a block diagram of a control device of the feeding device according to the embodiment of the present invention.

FIG. 12 is a diagram showing stress characteristics of a dispersed electrorheological fluid and a homogeneous electrorheological fluid.

FIG. 13 is a view showing the principle of a mechanism for generating an electrorheological fluid in a dispersed system.

FIG. 14 is a diagram showing a state in which a shear stress is generated by an electrorheological fluid.

FIG. 15 is a diagram showing a relationship between an electric field strength of an electrorheological fluid and a shear stress.

FIG. 16 is a diagram showing a relationship between a shear rate and a shear stress of an electrorheological fluid.

FIG. 17 is a schematic configuration diagram of an optical disk master recording apparatus.

FIG. 18 is a schematic configuration diagram of a power supply unit having a discharge circuit when the power is cut off.

FIG. 19 is a block diagram of a control device of a feeder according to another embodiment of the present invention.

FIG. 20 is a schematic enlarged perspective view of a part (magnetic fluid part) of another embodiment of the present invention.

[Explanation of symbols]

 1, 40, 41 Guide 2 Guide support member 3 Slide 4 Coil assembly 5 Yoke 6 Permanent magnet 7 Center yoke 8 Position detection scale 9 Reading head 10 Upper plate of moving stage 11 Moving plate 12 Container 13 First electrode 14 Second Electrode 15 Electrorheological fluid 16 Container base 17, 18 High-voltage cable 19 High-voltage power supply 21 Insulator 30 Subtractor 31 Proportional controller 32 Integral controller 34 Adder 35 Position detector 36 Differentiator 37 Braking device 43 Iron bar 44 Electromagnetic magnet 45 units 46 Arm 47 Master disk 51 Power switch 52 Resistance 101 Laser oscillator 102 Spindle motor 103 Slider 104 Recording lens 105 Beam spot monitor 106 Moving optical system 107 Optical disk master disk 108 ) 201 magnetic fluid 202 core 203 coil 204 power supply unit

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) // B23Q 5/28 H01L 21/30 503B (72) Inventor Yoshiko Fujita 1006 Odakadoma, Kadoma City, Osaka Matsushita Electric Industrial (72) Inventor Hirokazu Sato 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hironao Tsumaka 1006 Kadoma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 2F078 CA02 CA08 CB02 CB05 CB09 CB12 CB15 CB16 3F021 AA03 BA02 CA06 DA05 3J069 AA35 CC40 DD25 DD50 5D121 AA02 BB38 BB40 JJ03 5F046 CC01 CC19

Claims (10)

[Claims] 1. A container containing an electrorheological fluid, at least one movable plate which is at least partially movable in the electrorheological fluid, and a movable stage having the movable plate; A power supply unit for applying an electric field to the electrorheological fluid, which is an electric field in a direction substantially perpendicular to the moving direction of the moving plate and according to the moving speed of the moving stage, and a driving unit for moving the moving stage. Feeding device to be equipped. 2. A container containing an electrorheological fluid, at least one movable plate which is at least partially present in the electrorheological fluid and is movable, and a direction of movement of the movable plate substantially. A first electrode and a second electrode for generating an electric field in a direction perpendicular to the first electrode, the first electrode being fixed, and the second electrode being fixed to the second electrode or being disposed on the moving plate; A feeding unit configured to apply a voltage to the first electrode and the second electrode; a moving stage having the moving plate; and a driving unit configured to move the moving stage. A feeding device, wherein a distance between one electrode and the second electrode changes according to a position in the moving direction. 3. A container containing an electrorheological fluid, at least one movable plate which is at least partially present in the electrorheological fluid and is movable, and a moving direction of the moving plate substantially. A first electrode and a second electrode for generating an electric field in a direction perpendicular to the first electrode, the first electrode being fixed, and the second electrode being fixed to the second electrode or being disposed on the moving plate; A feeding unit configured to apply a voltage to the first electrode and the second electrode; a moving stage having the moving plate; and a driving unit configured to move the moving stage. The feeding device, wherein an area of a portion where the first electrode and the second electrode face each other changes according to the position in the moving direction. 4. The feeding device according to claim 3, wherein a distance between the first electrode and the second electrode changes according to a position in the moving direction. 5. A first container containing an electrorheological fluid and a second container, at least a part of which is present in the electrorheological fluid of the first container and is movable first. A plate, at least a part of which is present in the electrorheological fluid of the second container, and a movable second movable plate; and a movement having the first movable plate and the second movable plate. A feeding unit configured to generate an electric field in a direction substantially perpendicular to a moving direction of the first moving plate and the second moving plate; and a driving unit configured to move the moving stage. Wherein the respective vectors of stresses generated by the electrorheological fluid on the first moving plate and the second moving plate are substantially equal to each other with respect to a vertical plane including the center of gravity of the moving stage. Is symmetric, feeding device characterized in that. 6. The feeding device according to claim 5, wherein the first container and the second container are connected to each other. 7. A slide movably disposed along a guide, a container containing an electrorheological fluid, and at least one movable part at least partially in the electrorheological fluid and movable. A plate, a moving stage having the slide and the moving plate, a power supply unit for applying an electric field to the electrorheological fluid in a direction substantially perpendicular to a moving direction of the moving plate, and a driving unit for moving the moving stage. And a vector of a driving force of the driving unit and a vector of a force exerted by the stress of the electrorheological fluid on the moving stage on a vertical plane including a center of gravity of the moving stage. A feeding device, which is substantially present in the feeding device. 8. The moving plate according to claim 1, wherein the surface of the moving plate has a surface roughness larger than an average value of diameters of dispersed particles in the electrorheological fluid. Feeding device according to the paragraph. 9. The feeding device according to claim 1, wherein when the power supply of the feeding device is cut off, two electrodes connected to the power supply unit are short-circuited. apparatus. 10. The method according to claim 1, wherein the electrorheological fluid is replaced with a magnetic fluid, and the first electrode and the second electrode are replaced with a magnetic circuit having a gap. The feeding device according to claim.