JP4920389B2 - Stage equipment - Google Patents

Description

The present invention is based and, about the stage equipment having a table which moves relative to the base, a. Especially, a brake mechanism which utilizes an electric rheological (ER) gel sheet, about the stage equipment that enables highly accurate position fixing of the table.

  In Patent Document 1, as a stage device used for a sample stage of an optical microscope, a base, a table mounted on the base and freely moving in the XYθ direction within one plane, and the table are moved. A stage apparatus including the linear motor is disclosed. Since this stage apparatus uses a coreless type linear motor arranged on the base as a drive source, there is an advantage that the entire apparatus can be made thinner than the configuration using a linear guide as a drive source.

By the way, in such a stage device, if the position of the table is fixed only by the servo holding force of the linear motor, the holding force of the linear motor is small, so that the position of the table is shifted when receiving an external force. Can be considered. If the table is displaced from the predetermined position, it is necessary to detect the displacement with a sensor or the like, and re-drive the servo system including the linear motor and the servo amplifier that drives the motor to return the table to the predetermined position. The drive control becomes complicated. Furthermore, such a configuration is such that the table is returned only when a positional deviation occurs, and does not prevent the occurrence of the positional deviation in the first place.
On the other hand, it is conceivable to fix the position of the table using a mechanical brake mechanism. However, the mechanical brake mechanism is liable to cause a minute blur at the time of fixing, and therefore, it is difficult to obtain sufficient accuracy. .

On the other hand, a material called “electrorheological fluid” (electrorheological fluid, ER fluid, ERF) whose viscosity is changed by applying a voltage is conventionally known. The ER fluid is a fluid in which electrorheological particles (ER particles) are contained in a liquid medium. In recent years, further research has been conducted on this ER fluid, and Patent Document 2 proposes a material called “electrorheological gel (ERG)” and a sheet thereof in a gel form to prevent sedimentation of ER particles. Yes.
JP 2005-168154 A JP 2005-255701 A

As described above, in a stage apparatus that performs precise positioning, it is required that the position can be fixed with higher accuracy without increasing the size of the entire apparatus.
The present invention has been made in view of such problems, and its object is provided with a brake mechanism which utilizes an electric rheological (ER) gel sheet, the stage equipment that enables highly precise positional fixing of the table Ru near to provide.

In order to achieve the above object, a stage apparatus of the present invention includes a base, a table mounted on the base and moving relative to the base, a linear motor for moving the table, the table, and the base. And a brake mechanism that fixes the position of the table with respect to the base. The brake mechanism is provided on the table and the base and faces each other. A pair of electrode plates, and an ER gel sheet that is disposed between the pair of electrode plates and contains electrorheological particles (ER particles) in a gel-like medium, and the ER gel sheet is applied with a voltage. In the absence, the ER particles are raised on the surface of the gel-like medium, which causes the table to slide on the ER gel sheet. Therefore, when the voltage is applied, the ER particles sink into the medium, whereby the contact area between the surface of the gel-like medium and the table or the base is increased. The adhesiveness is increased to increase the position of the table, and the table is fixed in position, and further provided with urging means for pressing the brake mechanism toward the table or the base (always).
The urging means includes a leaf spring, a coil spring, a pneumatic mechanism, or a hydraulic mechanism that elastically deforms and generates a repulsive force.

According to the stage apparatus of the present invention, by applying a voltage to the brake mechanism, the ER particles of the ER gel sheet sink into the gel-like medium, and the contact area between the surface of the medium and the table increases. The position is fixed. In the case of such a configuration, since minute blurring is less likely to occur than in the case where a mechanical brake mechanism is used, the accuracy of position fixing can be improved.
Further, the ER gel sheet has a property that its thickness slightly contracts when a voltage is applied. However, according to the stage apparatus of the present invention, the ER gel sheet is pressed against the table or the base (always). Since the biasing means is provided, the influence of the minute change in the sheet thickness on the position fixing of the table is minimized, and as a result, the position fixing of the table can be performed with high accuracy.

The stage apparatus of the present invention may further include a holding member to which the brake mechanism is attached, and guide means for guiding the holding member so as to be movable in a direction perpendicular to the table.
According to such a configuration, the holding member and the brake mechanism attached thereto are guided in a direction (vertical direction) perpendicular to the table, and the movement in the lateral direction is suppressed, so that the position of the table is fixed. The accuracy can be further increased.

The table may be a rectangular table that moves relative to the base in the XYθ direction. In this case, it is preferable that the brake mechanism is provided on each of the four sides of the table.
According to such a configuration, since the brake mechanism is arranged over the entire periphery of the table, the fixing force of the brake mechanism can be uniformly applied to the table.

Other stage devices
A base, a table mounted on the base and moving relative to the base, a linear motor for moving the table, and the table disposed between the table and the base. A damper mechanism for adjusting a resistance force when moving relative to each other, wherein the damper mechanism is provided on the table and the base, respectively, and a pair of electrode plates facing each other; An ER gel sheet containing electrorheological particles (ER particles) in a gel-like medium disposed between a pair of electrode plates, and the ER particles are in a state where no voltage is applied. Floating on the surface of the gel-like medium, thereby allowing the table to move in a low friction state while sliding on the ER particles,
In a state where a voltage is applied, the ER particles sink into the medium, whereby the contact area between the surface of the gel-like medium and the table or the base becomes the magnitude of the applied voltage. Accordingly, the adhesiveness is increased and the resistance is adjusted, and the apparatus further comprises an urging unit that presses the damper mechanism toward the table or the base.

According to such a stage apparatus, since the table is provided with a damper mechanism that adjusts a resistance force when the table moves relative to the base, the voltage applied to the ER gel sheet can be changed to change the table and The frictional force with the base can be adjusted as appropriate. Thus, since the damper element is added to the mechanical system, hunting peculiar to the servo can be suppressed according to this stage device. In addition, if a voltage is always applied to the ER gel sheet, the responsiveness can be improved.

Further, machining apparatus, comprising the present invention, a stage apparatus provided with a brake mechanism, a tool for machining the workpiece in contact with the workpiece to be held on the table of the stage apparatus, the said at the time of machining start the tool comes into contact with the workpiece, the ER gel sheet a voltage is applied to the table Ru fixed in position on the base.

  Thus, when the stage apparatus of the present invention is used in a processing apparatus, it is preferable to apply a voltage to the ER gel sheet at the time of “start of processing” when the tool contacts the workpiece. By applying a voltage, the table and the base are fixed to each other, and the apparent rigidity between the two is increased. For this reason, it is possible to suppress positional deviation due to micro vibration (chatter) of the table and processing load at the beginning of processing.

Also, other processing devices, the upper SL, a stage apparatus provided with a damper mechanism, the processing apparatus comprising a tool, the machining of the workpiece in contact with the workpiece to be held on the table of the stage apparatus In this case, the resistance force is adjusted in accordance with the processing situation.

As described above, according to the present invention, a brake mechanism which utilizes an electric rheological (ER) gel sheet, Ru can provide stage equipment that enables highly accurate position fixing of the table.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an exploded perspective view showing an embodiment of the stage apparatus of the present invention.

(First embodiment)
As shown in FIG. 1, the XYθ stage apparatus 1 of this embodiment includes a base 41 and a table 21 mounted on the base 41 and moving relative to the base 41. Further, a linear motor 20 for moving the table 21 is provided between the base 41 and the table 21.
In the present embodiment, a basic configuration in which the table 21 is simply placed on the base 41 will be described. However, an example in which the four corners of the table 21 are sandwiched between a pair of upper and lower balls (see FIG. 4). Will be described later in another embodiment.

  Both the base 41 and the table 21 have a substantially square outline shape. In the present embodiment, the base 41 and the table 21 have substantially the same size, but the present invention is not limited to this. For example, the table 21 may be formed slightly smaller than the base 41. Further, the corners of the table 21 and the base 41 may be chamfered.

  Roller mechanisms 46 for supporting the table 21 are provided at the four corners of the upper surface of the base 41, respectively. The roller mechanism 46 includes a ball 49, hard disks 48 and 48 that sandwich the ball 49 from above and below, and square holding plates 47 and 47 that hold the disks 48.

  The upper holding plate 47 is attached to the four corners of the lower surface of the table 21. The lower holding plate 47 is attached to the four corners of the upper surface of the base 41. A round hole 47a is formed at the center of each holding plate 47, and a disc 48 is fitted into the hole 47a. With such a configuration, a circular recess is formed by the inner periphery of the hole 47a and one surface of the disc 48, and the ball 49 is arranged in the recess.

  The table 21 is mounted on the base 41 via the roller mechanism 46 configured as described above, and a ball 49 is interposed between the table 21 and the base 41. With such a configuration, a certain distance is secured between the table 21 and the base 41, and the table 21 can freely move in the XYθ direction with respect to the base 41 in one plane.

  The linear motor 20 is made of a ferromagnetic material and is attached to the lower surface of the table 21 in the form of elongated plate-like permanent magnets 26X, 26X, 26Y, and 26Y (hereinafter also simply referred to as “permanent magnet 26”). Correspondingly, flat coils 24X, 24X, 24Y, 24Y (hereinafter also simply referred to as “flat coil 24”) provided on the base 41 are provided.

  The four permanent magnets 26X, 26X, 26Y, and 26Y are arranged to form a square. Specifically, a pair of permanent magnets 26 </ b> X and 26 </ b> X are arranged on the Y axis so as to sandwich the central hole 27 of the base 41 and are parallel to each other. The other pair of permanent magnets 26Y, 26Y are arranged on the X axis so as to sandwich the same hole 27, and are parallel to each other. Each flat coil 24 is arranged below each magnet 26 corresponding to each permanent magnet 26.

The permanent magnets 26X, 26X and the flat coils 24X, 24X are for moving the table 21 in the X direction. The other pair of permanent magnets 26Y, 26Y and the flat coils 24Y, 24Y move the table 21 in the Y direction. It is for moving.
Each flat coil 24 has a rectangular outline shape and is formed thin on the upper surface of the base 41. Each flat coil 24 is arranged in a positional relationship such that the longitudinal direction of the flat coil 24 is orthogonal to the longitudinal direction (SN pole) of the permanent magnet 26.

  When the table 21 is mounted on the base 41, an attractive force is generated between the permanent magnets 26X, 26X, 26Y, 26Y and the base 41, whereby the table 21 and the base 41 are attracted to each other. However, since the ball 49 of the roller mechanism 46 is interposed between the table 21 and the base 41 as described above, the distance between the members 21 and 41 is kept constant.

Next, the brake mechanism 50 using an electrorheological (ER) gel sheet will be described.
As shown in FIG. 1, the brake mechanisms 50 are arranged one by one at positions corresponding to the four sides of the table 21 between the table 21 and the base 41. The brake mechanism 50 includes an ER gel sheet 55 (detailed below) and a pair of electrode plates (an upper electrode plate 52A and a lower electrode plate 52B) that sandwich the sheet 55 from above and below.

The upper electrode plate 52 </ b> A is provided on the lower surface of the table 21. The lower electrode plate 52B is provided on the upper surface of the base 41 via an elastic body 58 (described later in detail). Both electrode plates 52A and 52B are sheet-like electrodes made of an aluminum alloy or the like, and are formed to have substantially the same size as the upper and lower surfaces of the ER gel sheet 55.
In the present embodiment, as an example, only the upper electrode plate 52 </ b> A can slide with respect to the ER gel sheet 55, and the lower electrode plate 52 </ b> B does not slide with respect to the ER gel sheet 55. In order to realize this, for example, only the lower electrode plate 52B is roughened, the frictional resistance between the lower electrode plate 52B and the ER gel sheet 55 is relatively increased, and the upper electrode 52A and the ER gel sheet 55 are relatively increased. The sliding between the two should be given priority.

FIG. 2 is a longitudinal sectional view taken along the line AA in FIG. 1 and shows the configuration of the brake mechanism 50.
The ER gel sheet 55 is a new functional material whose physical properties (shearing force and the like) change when a voltage is applied. As shown in FIG. 2, the ER gel sheet 55 contains ER particles 57 in a gel-like medium 59, and is a sheet as a whole. It is formed in a shape. As this ER gel sheet 55, what was disclosed by Unexamined-Japanese-Patent No. 2005-255701 can be used, for example. The ER gel that is a material of the ER gel sheet 55 has a structure in which a liquid electrical insulating medium in which ER particles 57 are dispersed in a gel skeleton is enclosed.

  The ER particles 57 are spherical particles having good sliding characteristics and are dispersed in an electrically insulating medium to exhibit an ER effect. An example is solid particles or carbon particles that adsorb and store water on the surface of the particles, such as silica gel, cellulose, starch, soybean casein, and polystyrene ion exchange resins.

  Examples of the liquid electrically insulating medium include silicone oil, diphenyl chloride, and trans oil. Of these, silicone oil is preferably used because it has excellent electrical insulation, is physically and chemically stable, and has high flame retardancy.

  In this ER gel sheet 55, since the liquid insulating medium in which the ER particles 57 are dispersed is held in the gel skeleton, the ER particles 57 do not settle and aggregate. Further, since it is in the form of a sheet, it is easy to handle, and no special sealing mechanism is required when it is incorporated into the stage mechanism 1.

The ER gel sheet 55 configured as described above operates according to the following mechanism.
First, as shown in FIG. 2A, in the state where no voltage is applied between the upper and lower electrode plates 52A and 52B, the ER particles 57 are raised from the surface of the gel-like medium 59. Since the ER particles 57 are restrained by the gel-like medium 59, they do not move greatly in the medium.

  Thus, in a state where the ER particles 57 are raised, the ER particles 57 and the upper electrode plate 52A are in a low friction state, and the upper electrode plate 52A (and the table 21 to which the upper electrode plate 52A is attached) has a low friction on the ER gel sheet 55. It can slide in the state.

On the other hand, as shown in FIG. 2B, when a voltage is applied between the upper and lower electrode plates 52A and 52B, the ER particles 57 are attracted to each other, and the particles floating on the surface of the gel-like medium 59 Sink into. Due to this sinking, the contact area between the upper electrode plate 52A and the gel-like medium 59 gradually increases.
Here, since the gel-like medium 59 has very high wettability, the adhesion to the upper electrode plate 52A increases as the contact area increases in this way. As a result, the upper electrode plate 52A (and the table 21 to which it is attached) becomes immovable with respect to the base 41, and the position is fixed on the spot.

  By the way, the ER gel sheet 55 has a property that its thickness slightly contracts as the voltage is applied and the ER particles 57 sink into the gel medium 59. For example, a sheet having a thickness of 0.5 mm may shrink by about 2 μm. In order to minimize the influence of the minute change in the thickness of the ER gel sheet on the position fixing accuracy of the stage apparatus 1, the stage apparatus 1 of the present embodiment has a lower part of the brake mechanism 50 as shown in FIG. An elastic body 58 is provided.

The elastic body 58 is not particularly limited as long as it is elastically deformed and generates a repulsive force. For example, a plate spring, a coil spring, a pneumatic mechanism, or a hydraulic mechanism can be used. FIG. 3 is a side view schematically showing the relationship between the brake mechanism 50 and the elastic body 58. 3A shows a state where no voltage is applied to the brake mechanism 50, and FIG. 3B shows a state where a voltage is applied.
As shown in FIG. 3A, the table 21 is only placed on the base 41 via the ball 49, but the table 21 includes the weight of the table 21 and / or the above-described permanent. A downward force due to the attractive force of the magnet 26 (see FIG. 1) is applied. Therefore, even if the ER particles 57 float on the upper surface of the gel-like medium 59, the entire table 21 is not lifted naturally.

  The elastic body 58 is disposed between the brake mechanism 50 and the base 41 in a slightly compressed state. The repulsive force generated by the compression of the elastic body 58 acts on the lower electrode plate 52 </ b> B of the mechanism 50 as an urging force that presses the entire brake mechanism 50 toward the table 21.

  In the stage apparatus 1 according to the present embodiment, the elastic body 58 is interposed under the brake mechanism 50 using the ER gel sheet 55 as described above, and the brake mechanism 50 is caused to move by the urging force from the elastic body 58. 3B, even if a voltage is applied to the brake mechanism 50 and the thickness of the ER gel sheet 55 is slightly contracted as shown in FIG. (Specifically, "upper electrode plate 52A") can be satisfactorily adhered. Therefore, the contact area between the ER gel sheet 55 and the lower surface of the table 21 (specifically, the upper electrode plate 52A) is sufficiently maintained, and a sufficient fixing force for fixing the position of the table 21 can be obtained.

  In addition, when the thickness of the sheet 55 contracts while the upper surface of the ER gel sheet 55 is adhered to the lower surface (upper electrode plate 52A) of the table 21, a downward force acts on the central portion of the side of the table 21. It becomes. Therefore, in some cases, the table 21 is slightly deformed by the force and may affect the flatness of the table 21, but according to the present invention, the ER gel sheet 58 is moved to the table 21 side by the elastic body 58. Such a problem is less likely to occur because it is pressed toward

As mentioned above, although one form of this invention was demonstrated referring drawings, this invention is not limited to the said structure, A various change is possible.
For example, contrary to the above configuration, the frictional force between the table 21 and the base 41 is high when no voltage is applied, and the frictional force between the table 21 and the base 41 is reduced when a voltage is applied. It can also be set as the structure to do.

(Second Embodiment)
FIG. 4 is a longitudinal sectional view showing another example of the stage apparatus of the present invention. FIG. 5 is an exploded perspective view showing a roller mechanism (spherical guide mechanism) at the corner of the stage apparatus of FIG.
The stage apparatus shown in FIG. 4 has a structure in which the four corners (see FIG. 1) of the table 21 are sandwiched and supported by a pair of upper and lower balls 49A and 49B.

  As shown in FIG. 5, the lower ball 49 </ b> B is disposed in a circular recess at the center of a ring-shaped holding member 47 </ b> B disposed on the base 41. The upper ball 49A is also disposed in a similar ring-shaped holding member 47A. The holding member 47A is attached to the lower surface of the upper plate 45 disposed above the table 21 with a predetermined gap between the holding member 47A and the table 21. The upper plate 45 is fixed to the upper end of an L-shaped member 44 formed in an L shape along the corner of the upper surface of the base 41, and is parallel to the table 21.

In this embodiment, with such a configuration, the four corners of the table 21 are supported by a pair of upper and lower balls 49A and 49B, and the table 21 can freely move in the XYθ direction within one plane. In this configuration, since the four corners of the table 21 are pressed from above by the upper balls 49A, the table 21 does not lift upward.
Even with such a configuration, the effects of the present invention as described above can be obtained in the same manner as in the above-described embodiment (see FIG. 1).

(Third embodiment)
FIG. 6 is a longitudinal sectional view showing still another example of the stage apparatus of the present invention.
In the stage apparatus shown in the figure, a brake mechanism 50 using an ER gel sheet 55 is disposed on an elastic body 58 via a block 51. The repulsive force from the elastic body 58 acts on the lower surface of the brake mechanism 50 through the block 51 as described above.

  Around the elastic body 58 and the block 51, guide side walls 61 </ b> A and 61 </ b> B rising upward from the base 41 toward the table 21 are provided. A roller 61C similar to a linear bearing is interposed between the side walls 61A and 61B and the side surface of the block 51, whereby the block 51 and the brake mechanism 50 disposed on the upper side thereof are laterally moved. Movement is limited, and the movement is allowed only in the vertical direction (direction perpendicular to the table 21).

  In the case of the configuration of the above embodiment as shown in FIG. 3, when a lateral force is applied from the table 21 to the brake mechanism 50, the force is also transmitted to the elastic body 58, and the elastic body 58 is laterally moved. There is a possibility that the table 21 is slightly displaced from the predetermined position by the deformation. On the other hand, in the configuration of the present embodiment, the side walls 61A, 61B and the like are provided to prevent the block 51 (and thus the brake mechanism 50 disposed on the upper side) from moving in the lateral direction. A slight positional shift is prevented, and the accuracy of fixing the position of the table 21 can be further improved.

  Note that the above-described stage apparatus (for example, the stage apparatus 1 in FIG. 1) can be used by being mounted on a processing apparatus, for example. In this case, it is preferable that a voltage is applied to the ER gel sheet 55 when the tool of the processing apparatus comes into contact with the workpiece held on the table 21 of the stage apparatus 1 (this is referred to as “processing start”). . Thereby, the position of the table 21 and the base 41 is fixed to each other, and the apparent rigidity between them increases. For this reason, it is possible to suppress the positional deviation due to the slight vibration (chatter) of the table 21 and the processing load at the start of processing.

  Further, the ER gel sheet 55 can be used as a damper mechanism in a stage apparatus, and such a stage apparatus can be used by being mounted on a processing apparatus.

It is a disassembled perspective view which shows one form of the stage apparatus of this invention. It is a longitudinal cross-sectional view in the AA cutting line of FIG. 1, and has shown the structure of the brake mechanism using an electrorheology (ER) gel sheet. It is a side view which shows typically the relationship between a brake mechanism and an elastic body. It is a longitudinal cross-sectional view which shows the other example of the stage apparatus of this invention. It is a disassembled perspective view which shows the roller mechanism (spherical guide mechanism) in the corner part of the stage apparatus of FIG. It is a longitudinal cross-sectional view which shows the other example of the stage apparatus of this invention.

Explanation of symbols

1 ... Stage device,
20 ... Linear motor, 21 ... Table, 24X, 24Y ... Flat coil, 26X, 26Y ... Permanent magnet, 27 ... Hole 41 ... Base, 44 ... L-shaped member, 45 ... upper plate, 46 ... roller mechanism, 47 ... holding plate, 47A, 47B ... holding member, 47a ... hole, 49, 49A, 49B ... ball 50 ... brake Mechanism, 52A, 52B ... Electrode plate, 55 ... ER gel sheet, 57 ... ER particle, 58 ... Elastic body, 59 ... Gel-like medium 61A, 61B ... Side wall, 61C ...・ Colo

Claims (5)

Base and
A table mounted on the base and moving relative to the base;
A linear motor for moving the table;
A stage device provided between the table and the base, and a brake mechanism for fixing the position of the table with respect to the base,
The brake mechanism is
A pair of opposing electrode plates provided on the table and the base, respectively,
An ER gel sheet that is disposed between the pair of electrode plates and contains electrorheological particles (ER particles) in a gel-like medium;
The ER gel sheet is
In a state where no voltage is applied, the ER particles are raised on the surface of the gel-like medium, thereby allowing the table to move in a low friction state while sliding on the ER gel sheet,
In a state where a voltage is applied, the ER particles sink into the medium, thereby increasing the contact area between the surface of the gel-like medium and the table or the base, thereby increasing adhesion, The table is fixed in position,
A stage device further comprising urging means for pressing the brake mechanism toward the table or the base.   The stage device according to claim 1, wherein the biasing means is a plate spring or a coil spring that elastically deforms to generate a repulsive force. A holding member to which the brake mechanism is attached;
The stage apparatus according to claim 1, further comprising guide means for guiding the holding member so as to be movable in a direction perpendicular to the table. The table is a rectangular table that moves relative to the base in the XYθ direction,
The stage apparatus according to any one of claims 1 to 3, wherein the brake mechanism is provided on each of the four sides of the table. Base and
  A table mounted on the base and moving relative to the base;
  A linear motor for moving the table;
  A stage device provided between the table and the base, and a brake mechanism for fixing the position of the table with respect to the base,
  The brake mechanism is
  A pair of opposing electrode plates provided on the table and the base, respectively,
  An ER gel sheet that is disposed between the pair of electrode plates and contains electrorheological particles (ER particles) in a gel-like medium;
  The ER gel sheet is
  In a state where a voltage is applied, the ER particles are raised on the surface of the gel-like medium, thereby allowing the table to move in a low friction state while sliding on the ER gel sheet,
  In the state where no voltage is applied, the ER particles sink into the medium, thereby increasing the contact area between the surface of the gel-like medium and the table or the base, thereby increasing the adhesion, The table is fixed in position,
  A stage device further comprising urging means for pressing the brake mechanism toward the table or the base.

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