JP7371860B2 - Electrostatic adsorption device and contact member manufacturing method - Google Patents

Description

The present invention relates to an electrostatic chuck device and a method for manufacturing a contact member.

The electrostatic adsorption device described in Patent Document 1 includes a deformable surface for contacting the surface of an object (article), and a pair of electrodes for applying a voltage to this surface. This device is said to generate electrostatic adhesion force (electrostatic force) on the object by the potential difference between a pair of electrodes.

Patent No. 5038405

When the electrostatic adsorption device described in Cited Document 1 was verified, the adsorption force (electrostatic adsorption force) required by the inventors could not be obtained. Furthermore, for example, when the object is a cardboard container, its surface has minute irregularities, so even if the surface is deformable like the electrostatic adsorption device of Patent Document 1, there is a gap between the object and the object. There is a problem in that many gaps remain, making it impossible to obtain sufficient suction power for the object. Moreover, accommodating articles inside the cardboard container increases the weight. Therefore, it is desired to increase the adsorption force by electrostatic adsorption even for objects with rough surfaces such as cardboard containers.

The present invention provides an electrostatic chucking device that can increase the adsorption force to an object and reliably hold the object, and a method for manufacturing a contact member made of a dielectric material used in this electrostatic chucking device. With the goal.

An electrostatic adsorption device according to an aspect of the present invention includes a contact member made of a dielectric material having a contact surface that can be deformed to follow the surface of an object, and a pair of electrodes capable of applying a voltage to the contact member, The contact surface has an uneven portion in which a concave portion and a convex portion are continuous in one arbitrary direction along the surface and in a direction intersecting this one direction and along the surface. Further, the contact surface is formed by being transferred using a transfer mold having a transfer surface formed by surface processing by shot blasting.

Further, the pair of electrodes may be provided in contact with the contact member and may be deformable together with the contact member. Further, the surface roughness of the contact surface due to the uneven portion may be smaller than the surface roughness of the surface of the object. Further, the maximum height roughness Rz of the surface roughness due to the uneven portions of the contact surface may be 0.1 μm or more and 7.0 μm or less. Further, the contact surface may have an average length AR of a roughness motif of 90 or less in a motif parameter of surface roughness due to the uneven portion. Further, in the contact surface, the average value of the difference in height between the concave portion and the convex portion in the uneven portion may be smaller than the average value on the surface of the object. Further, the shear friction force generated between the object and the contact surface when the surface of the object is adsorbed may be 3.0 mN/mm ² or more .

A method for manufacturing a contact member according to an aspect of the present invention is a method for manufacturing a contact member that is included in an electrostatic adsorption device that adsorbs an object and has a contact surface that can be deformed to follow the surface of the object, the method comprising: The method includes forming irregularities on the transfer surface of the transfer mold, supplying and solidifying a liquid dielectric material for forming a contact member onto the transfer surface, and removing the contact member from the transfer surface. .

The method may also include forming irregularities on the transfer surface by colliding particles with the transfer surface of the transfer mold. Moreover, the material of the particles may be SUS (stainless steel) or iron, and the particle size may be from 0.2 mm to 0.3 mm. Further, the transfer mold has an outer frame member on the outer peripheral side of the transfer surface that protrudes upward from the transfer surface and surrounds the transfer surface, and includes supplying a liquid contact member material to the inside of the outer frame member. But that's fine.

According to the electrostatic adsorption device according to the aspect of the present invention, by applying a voltage to the contact member using the pair of electrodes, the contact member generates electrostatic force and adsorbs the object. When an object is attracted by electrostatic force, if the surface of the object is rough, the contact surface of the contact member not only deforms to follow the surface of the object, but also forms irregularities on the contact surface. The rate at which the concave portions and convex portions fit into the concave portions and convex portions of the rough surface of the object is high, and the contact area becomes large. As a result, the adhesion force (electrostatic adsorption force) to the object increases, and the object is firmly adsorbed. Therefore, the object is securely held.

In addition, in a configuration in which a pair of electrodes is provided in contact with a contact member and is deformable together with the contact member, the pair of electrodes deforms together with the contact member, so that the contact member deforms following the surface of the object. You can increase your sexuality. In addition, if the surface roughness of the contact surface due to the unevenness is smaller than the surface roughness of the surface of the object, when this contact surface comes into contact with the surface of the object, the recesses and projections of the unevenness will be affected. Since it adapts well to the unevenness of the object, the gap between the contact surface and the object is small, the contact area between the contact surface and the surface of the object is large, and the adsorption force to the object is large. Furthermore, in a configuration in which the maximum height roughness Rz of the surface roughness due to the uneven portion of the contact surface is 0.1 μm or more and 7.0 μm or less, the contact between the uneven portion of the contact surface and the surface of the object is good. . Further, in the contact surface, when the average length AR of the roughness motif in the motif parameter of the surface roughness due to the uneven portion is 90 or less, the contact between the uneven portion of the contact surface and the surface of the object is good.

In addition, if the average value of the difference in height between the concave and convex portions of the uneven portion of the contact surface is smaller than the average value of the height difference of the surface of the object, the difference between the uneven portion of the contact surface and the surface of the object Good contact condition. In addition, in a configuration in which the shear friction force generated between the object and the contact surface when the surface of the object is adsorbed is 3.0 mN/mm ² or more, the contact surface does not easily come off from the surface of the object. The object is securely held. Further, in a configuration in which the contact surface is formed by transfer using a transfer mold having a transfer surface formed by surface processing by shot blasting, a contact surface having appropriate unevenness can be realized. Furthermore, in a configuration in which the holding member that holds the contact member is further provided, and the holding member has a holding surface that holds the contact member, the contact member is held on the holding surface, so that the deformable contact member is securely held. At the same time, the contact surface contacts the object in a well-balanced manner.

According to the method for manufacturing a contact member according to an aspect of the present invention, the contact member is formed by solidifying the liquid dielectric material supplied onto the transfer surface, and the contact member has irregularities formed on the transfer surface. is transcribed. As a result, a contact member having a contact surface having an uneven portion can be easily formed.

Furthermore, in a configuration that includes forming unevenness on the transfer surface by colliding particles with the transfer surface of the transfer mold, the unevenness on the transfer surface can be easily formed. Further, in the case where the material of the particles is SUS or iron and the particle size is 0.2 mm to 0.3 mm, the unevenness of the transfer surface can be formed with high accuracy. Further, the transfer mold has an outer frame member on the outer peripheral side of the transfer surface that protrudes upward from the transfer surface and surrounds the transfer surface, and includes supplying a liquid dielectric material to the inside of the outer frame member. In this embodiment, the outer periphery of the contact member can be defined by the outer frame member while forming a predetermined uneven portion on the contact surface of the contact member. Moreover, the thickness of the contact member can be easily defined by the height of the outer frame member.

FIG. 1 is a diagram showing an example of an electrostatic adsorption device according to an embodiment. It is a figure which shows an example of the cross section of the uneven|corrugated part formed in the contact surface of the contact member in an electrostatic adsorption device. FIG. 3 is a plan view showing an example of a pair of electrodes in the electrostatic adsorption device. It is a flowchart which shows an example of the manufacturing method of a contact member. FIG. 2 is a cross-sectional view showing an example of a transfer mold used in the method for manufacturing a contact member. FIG. 3 is a cross-sectional view showing a mold material for forming a transfer mold. FIG. 3 is a cross-sectional view showing a state in which the upper surface of the mold material is processed by shot blasting to form a transfer surface of a transfer mold. FIG. 3 is a cross-sectional view showing a state in which contact member material is supplied onto the transfer surface of the transfer mold. FIG. 3 is a cross-sectional view showing a state in which a contact member is created by solidifying the contact member material on the transfer surface. FIG. 3 is a cross-sectional view showing a state in which the contact member is taken out from the transfer surface of the transfer mold. 2 is an observation image showing the contact surface of a suction pad formed under the conditions of Example 1. 3 is an observed image showing the contact surface of a suction pad formed under the conditions of Comparative Example 2. 3 is an observation image showing the contact surface of a suction pad formed under the conditions of Comparative Example 3. FIG. 7 is a diagram showing shear friction force for each pattern of electrodes in a state in which a cardboard container is electrostatically attracted in an example.

Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to this form. In addition, in order to explain the embodiments, the drawings are shown by changing the scale as appropriate, such as by enlarging or emphasizing some parts, and the size, shape, etc. may differ from the actual product. .

FIG. 1 is a diagram showing an example of an electrostatic adsorption device ED according to an embodiment. As shown in FIG. 1, the electrostatic adsorption device ED according to the present embodiment includes an adsorption pad AP, a pad holding member PH, and a voltage application section PS. The electrostatic adsorption device ED electrostatically adsorbs, for example, a cardboard container (object) OB as an object. The electrostatic attraction device ED attracts and holds the cardboard container OB with a suction pad AP.

Note that the electrostatic chuck device ED is capable of suction-holding not only a cardboard container OB but also an object having a rough surface, such as a plywood board or concrete. Furthermore, the electrostatic attraction device ED can be used to attract and hold not only objects with rough surfaces but also objects with smooth surfaces.

The suction pad AP includes a pad end AP1 and a pad base AP2, and the pad end AP1 includes a contact member 11 and a pair of electrodes 12 and 13 capable of applying a voltage to the contact member 11. A pair of electrodes 12 and 13 are provided between pad base AP2 and contact member 11. The contact member 11 has a contact surface 11f facing the surface OBf of the cardboard container OB on one side located on the opposite side from the pad base AP2 and the pair of electrodes 12, 13. The pad end AP1 is a layer from the pair of electrodes 12 and 13 to the contact surface 11f. Pad base AP2 is a layer other than pad end AP1 in suction pad AP. By applying a voltage to the pair of electrodes 12 and 13, electrostatic adsorption force is generated on the contact surface 11f of the contact member 11, and the adsorption pad AP adsorbs the cardboard container OB. The contact member 11 has, for example, a rectangular contact surface 11f, and each side is set to about 10 mm to 500 mm. Further, the contact member 11 may be provided in a disc shape other than a rectangle, and may have an outer diameter of about 10 mm to 500 mm, for example. The thickness of the contact member 11 is set to, for example, approximately 30 μm to 800 μm. In this embodiment, the contact member 11 has a thickness of, for example, about 80 μm.

At least the contact surface 11f of the contact member 11 can be deformed to follow the surface OBf of the cardboard container OB. In this embodiment, the entire suction pad AP can be deformed to follow the surface OBf of the cardboard container OB, but is not limited to this form. For example, in the thickness direction (direction perpendicular to the contact surface 11f) connecting the contact surface 11f of the contact member 11 and the pair of electrodes 12, 13, only a part of the contact surface 11f side follows the surface OBf of the cardboard container OB. It may also be possible to deform it.

The suction pad AP is formed of a dielectric material and has both dielectric properties and insulating properties. The suction pad AP can be suctioned onto both an insulator and a conductor by applying a predetermined voltage to a pair of electrodes 12 and 13. For example, a material with a resistivity greater than about 10 ¹² Ω·cm may be defined as an insulator. Also, for example, a material having a resistivity of less than about 10 ¹² Ω·cm may be defined as an electrical conductor. Further, the suction pad AP is made of a dielectric material having elasticity and flexibility that allows it to be deformed following the surface OBf of the cardboard container OB. In this embodiment, the suction pad AP is illustrated and explained separately into a pad end AP1 and a pad base AP2 for convenience of the manufacturing method described later, but the suction pad AP is used for the pad end AP1 and the pad base AP2. The dielectric material is the same material.

Note that the dielectric material is not limited to a material that allows the formed suction pad AP to be elastically deformed. For example, the dielectric material forming the suction pad AP may be a material for forming a thin film or layered body that is bendable but does not substantially elastically expand or contract. Further, the dielectric material forming the suction pad AP preferably has flexibility with an elastic modulus of less than 10 MPa, particularly less than 1 MPa, for example.

Examples of such dielectric materials include rubber-based materials, resin-based materials, and the like. More specifically, examples of the dielectric material forming the suction pad AP include crosslinkable rubber, non-crosslinkable thermoplastic elastomer, and soft resin. Examples of crosslinkable rubber used as a dielectric material forming the suction pad AP include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), and butyl rubber (IIR). , acrylonitrile butadiene rubber (NBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), acrylic rubber (ACM), chlorosulfonated polyethylene rubber (CSM), urethane rubber (U), silicone rubber (Q), Examples include fluororubber (FKM), epichlorohydrin rubber (CO), polysulfide rubber (T), and polydimethylsiloxane (PDMS).

In addition, non-crosslinkable thermoplastic elastomers used as dielectric materials forming the suction pad AP include, for example, styrene-based, olefin-based, urethane-based, polyester-based, polyamide-based, polyimide-based, vinyl chloride-based, fluorine-based, Examples include various thermoplastic elastomers such as acrylic.

In addition, examples of the soft resin used as the dielectric material forming the suction pad AP include ethylene vinyl acetate resin (EVA), soft polyester resin, low density polyethylene, polyurethane (PU), polypropylene (PP), acrylic resin, etc. In addition, various soft resins such as resins made by adding plasticizers to various resins can be used.

Further, the dielectric material forming the suction pad AP may include various composite materials such as fiber reinforced plastic (FRP) using glass fiber or carbon fiber, glass, ceramic, etc.

FIG. 2 is a diagram showing an example of a cross section of the uneven portion 15 formed on the contact surface 11f of the contact member 11 in the electrostatic adsorption device ED. As shown in FIG. 2, the contact surface 11f of the contact member 11 has an uneven portion 15. The uneven portion 15 has a concave portion 15a that is depressed in a direction perpendicular to the surface direction of the contact surface 11f, and a convex portion 15b that protrudes in a direction perpendicular to the surface direction of the contact surface 11f. These concave portions 15a and convex portions 15b are formed over the entire surface of the contact surface 11f. That is, the concave portion 15a and the convex portion 15b are formed continuously on the contact surface 11f in both an arbitrary direction along the surface and a direction intersecting this one direction and along the surface. .

The concave portions 15a and the convex portions 15b may be formed continuously and regularly along one direction and the intersecting direction of the contact surface 11f, or may be formed irregularly (randomly) without regularity. good. The contact surface 11f having such an uneven portion 15 is obtained by using a transfer mold TD having a transfer surface 51f formed by surface processing by shot blasting, and forming a transfer pattern on the transfer surface 51f of the transfer mold TD, as will be described in detail later. is formed by being transferred.

It is preferable that the surface roughness of the contact surface 11f due to the uneven portion 15 is smaller than the surface roughness of the surface OBf of the cardboard container OB, which is the object. As a result, when the contact surface 11f comes into contact with the surface OBf of the cardboard container OB, the concave portions 15a and the convex portions 15b are deformed to follow the surface OBf of the cardboard container OB, and the uneven portion 15 of the contact surface 11f and the convex portion 15b of the cardboard container OB are The contact area with the surface OBf increases. This increase in the contact area suppresses the formation of a gap between the surface OBf and the uneven portion 15, and increases the electrostatic attraction force.

Further, it is preferable that the maximum height roughness Rz of the surface roughness due to the uneven portion 15 of the contact surface 11f is 0.1 μm or more and 7.0 μm or less. By setting the maximum height roughness Rz of the contact surface 11f to 0.1 μm or more and 7.0 μm or less, the contact area between the surface of the object and the contact surface 11f increases even if the surface of the object is rough. Further, a more preferable range of the maximum height roughness Rz on the contact surface 11f is 1.0 μm or more and 5.0 μm or less. When the maximum height roughness Rz of the contact surface 11f is 1.0 μm or more and 5.0 μm or less, the contact area between the surface of the object and the contact surface 11f is further increased. Further, a more preferable range of the maximum height roughness Rz on the contact surface 11f is 4.0 μm or more and 5.0 μm or less. By setting the maximum height roughness Rz of the contact surface 11f to 4.0 μm or more and 5.0 μm or less, the contact area of the object particularly with respect to the surface OBf (rough surface) of the cardboard container OB, for example, increases.

Further, the contact surface 11f preferably has an average length AR of a roughness motif in the surface roughness motif parameter (JISBO631) due to the uneven portion 15 of 90 or less. This configuration suppresses the formation of a gap between the surface of the object and the uneven portion 15, and increases the contact area between the surface of the object and the contact surface 11f. Further, in the contact surface 11f, it is preferable that the average value of the difference in height between the concave portion 15a and the convex portion 15b in the concave and convex portion 15 is smaller than the average value of the height of the concave and convex portions on the surface OBf of the cardboard container OB. This configuration prevents a large gap from forming between the surface of the object and the uneven portion 15, and increases the contact area between the surface of the object and the contact surface 11f.

As described above, since the contact surface 11f of the contact member 11 is formed with the uneven portion 15, when the contact surface 11f comes into contact with the surface OBf of the cardboard container OB, which is the object, the recessed portion 15a and the convex portion 15b are roughened. It is deformed along the surface OBf. Therefore, the contact surface 11f and the surface OBf come into contact without an excessive gap (in a state where the generation of a gap is suppressed).

The contact surface 11f attracts the surface OBf of the cardboard container OB by electrostatic attraction force generated by applying a voltage to the pair of electrodes 12 and 13. Note that the contact member 11 is designed such that the shear friction force generated between the cardboard container OB and the contact surface 11f is 3.0 mN/mm ² or more when the contact surface 11f adsorbs the surface OBf of the cardboard container OB. It is preferable that the material is selected and the uneven portions 15 are formed. The suction pad AP having such a contact surface 11f has a high electrostatic adsorption force to the cardboard container OB, which is the object.

A pair of electrodes 12 and 13 are used to apply voltage to contact member 11. As shown in FIG. 1, the pair of electrodes 12 and 13 are provided on the interface 11g between the contact member 11 and the pad base AP2. Note that the pair of electrodes 12 and 13 may be buried in the contact member 11. Further, the pair of electrodes 12 and 13 are provided not on the contact member 11 but on the pad base AP2 side, and when the pad end AP1 (in this case, the contact member 11) is attached to the pad base AP2, the contact member 11 is It may also be in the form of contacting the boundary surface 11g. Furthermore, the pair of electrodes 12 and 13 may be buried in the pad base AP2. The pair of electrodes 12 and 13 are provided facing each other with a gap (see FIG. 3) in between. A part of the contact member 11 or the pad base AP2, which is an insulator, is buried in the gap between the pair of electrodes 12 and 13. As a result, an insulating portion exists between the pair of electrodes 12 and 13.

FIG. 3 is a plan view showing an example of the pair of electrodes 12 and 13 in the electrostatic chuck device ED. As shown in FIG. 3, the pair of electrodes 12 and 13 each have electrode base portions 12a and 13a and a plurality of electrode portions 12b and 13b. Each of the electrode base 12a and the electrode part 12b is electrically connected to each of the electrode base 13a and the electrode part 13b. The plurality of electrode parts 12b and 13b are provided at intervals in the electrode width direction Da in which the electrode base parts 12a and 13a extend. Each electrode portion 12b, 13b extends in the electrode length direction Db orthogonal to the electrode width direction Da. The electrode portion 12b formed on one electrode 12 extends in the electrode length direction Db from the electrode base 12a toward the electrode base 13a of the other electrode 13. The electrode portion 13b formed on the other electrode 13 extends in the electrode length direction Db from the electrode base 13a toward the electrode base 12a of one electrode 12. In this way, the pair of electrodes 12 and 13 each have a comb-tooth shape, and are arranged to face each other in plan view.

The electrode portion 12b of the electrode 12 is arranged between two electrode portions 13b adjacent to each other in the electrode width direction Da in the electrode 13. Moreover, the electrode part 13b of the electrode 13 is arranged between two electrode parts 12b adjacent to each other in the electrode width direction Da in the electrode 12. As a result, the electrode portions 12b of the electrode 12 and the electrode portions 13b of the electrode 13 are alternately arranged at intervals in the electrode width direction Da.

In the pair of electrodes 12 and 13, it is preferable that a plurality of sets of electrode parts 12b and 13b that are adjacent to each other in the electrode width direction Da are provided. Further, it is preferable that the pair of electrodes 12 and 13 include three or more sets of electrode parts 12b and 13b that are adjacent to each other in the electrode width direction Da. Furthermore, it is particularly preferable that the pair of electrodes 12 and 13 include six or more sets of electrode parts 12b and 13b that are adjacent to each other in the electrode width direction Da. In addition, in the pair of electrodes 12 and 13, the number (number of pairs) of electrode parts 12b and 13b that are adjacent to each other in the electrode width direction Da is determined by the outer diameter of the suction pad AP, the weight of the cardboard container OB that is the object, and the surface OBf. It is selected appropriately depending on the roughness of the surface.

In addition, in the pair of electrodes 12 and 13, in order to increase the number (number of pairs) of electrode parts 12b and 13b that are adjacent to each other in the electrode width direction Da within the range of the outer diameter of the contact surface 11f of the contact member 11, It is preferable that the width dimension W of the electrodes 12b and 13b in the electrode width direction Da is small. For example, it is preferable that the width dimension W of the electrode parts 12b and 13b is 10 mm or less. Moreover, in the width dimension W, a more preferable dimension is 8 mm or less, and an especially preferable dimension is 6 mm or less. Similarly, in order to increase the number (number of pairs) of electrode parts 12b, 13b, it is preferable that the gap d in the electrode width direction Da of electrode parts 12b, 13b is small. For example, it is preferable that the gap d between the electrode parts 12b and 13b is 1 mm or less. Furthermore, a more preferable dimension of the gap d is preferably 0.5 mm or less.

Such a pair of electrodes 12 and 13 may be provided on the boundary surface 11g of the contact member 11 and may be deformable together with the contact member 11. For this reason, it is preferable that the pair of electrodes 12 and 13 be made of a thin film of conductive material containing various metal materials and have a thickness of 200 μm or less, for example.

The pad holding member PH holds the suction pad AP, as shown in FIG. The pad holding member PH is made of an insulating material such as resin or a non-conductive metal material. Further, when the pad holding member PH is formed of a conductive metal material or the like, an insulating material is interposed between the pad holding member PH and the suction pad AP. The pad holding member PH includes a mounting portion 21 that can be mounted on various machines.

The suction pad AP may be detachable from the pad holding member PH. This form allows the suction pad AP to be replaced. Note that the suction pad AP is attached to the pad holding member PH using, for example, a releasable adhesive or the like.

The voltage application unit PS applies a voltage to the contact member 11 of the suction pad AP, as shown in FIG. The voltage application section PS is electrically connected to a power source (not shown) and applies a predetermined voltage to the pair of electrodes 12 and 13. The voltage application section PS includes wirings 31A and 31B provided within the pad holding member PH and within the pad base AP2, and connectors 32A and 32B provided at the tips of the wirings 31A and 31B. The connectors 32A and 32B are electrically connected to the pair of electrodes 12 and 13, respectively.

The operation of the electrostatic adsorption device ED is controlled by a controller (not shown), and the application of voltage at the voltage application section PS is also controlled by this controller. When a voltage is applied to the contact member 11 by the voltage application unit PS via the pair of electrodes 12 and 13 of the suction pad AP, an electrostatic force is generated on the contact surface 11f of the contact member 11. By generating electrostatic force while the contact surface 11f of the contact member 11 is in contact with the surface OBf of the cardboard container OB, the cardboard container OB can be attracted to the contact surface 11f of the contact member 11.

When the electrostatic attraction device ED attracts the cardboard container OB by electrostatic force, the contact surface 11f of the contact member 11 deforms to follow the surface OBf of the cardboard container OB. At this time, the concave portions 15a and the convex portions 15b that constitute the concavo-convex portion 15 of the contact surface 11f are in a state that follows the fine concavities and convexities of the rough surface forming the surface OBf of the cardboard container OB, and The contact area with the contact surface 11f increases. As a result, the adsorption force to the surface OBf of the cardboard container OB becomes high, and the suction pad AP firmly adsorbs the cardboard container OB.

Next, a method for manufacturing the adsorption pad AP of the electrostatic adsorption device ED as described above will be explained. FIG. 4 is a flowchart illustrating an example of a method for manufacturing the contact member 11. FIG. 5 is a cross-sectional view showing an example of a transfer type TD used in the method for manufacturing the contact member 11. FIG. 6 is a sectional view showing a mold material 55 for forming the transfer mold TD. FIG. 7 is a cross-sectional view showing a state in which the upper surface 55a of the mold material 55 is processed by shot blasting to form a transfer surface 51f of the transfer mold TD. As shown in FIG. 4, the method for manufacturing the contact member 11 includes a transfer mold manufacturing step S1 and a contact member forming step S2.

The transfer mold manufacturing process S1 is a process of manufacturing a transfer mold TD for forming the contact member 11 of the suction pad AP. As shown in FIG. 5, the transfer mold TD includes a mold body 51 made of a metal material such as iron, aluminum, or SUS, a glass plate, a resin plate, or the like, and an outer frame member 52. The mold body 51 has a plate shape with a predetermined thickness, and has a transfer surface 51f for forming the contact surface 11f of the contact member 11 on its upper surface. The transfer surface 51f is provided with an unevenness 53 for forming the concave portion 15a and the convex portion 15b, which constitute the uneven portion 15 of the contact surface 11f, by transfer.

The outer frame member 52 is provided on the mold body 51. The outer frame member 52 is provided on the outer peripheral side of the transfer surface 51f so as to protrude upward from the transfer surface 51f and surround the transfer surface 51f. This outer frame member 52 has a rectangular opening 52a in a plan view in accordance with the outer shape of the contact member 11. In this embodiment, the outer frame member 52 is a frame-shaped body that is rectangular in plan view. The thickness of the outer frame member 52 (the height of the upward protrusion from the transfer surface 51f) is the same or almost the same as the thickness of the contact member 11 to be formed. That is, the thickness of the contact member 11 to be formed is set by the thickness of the outer frame member 52.

As shown in FIG. 4, the transfer mold manufacturing process S1 includes an unevenness forming process S11 and an outer frame member attaching process S12. In the unevenness forming step S11, as shown in FIG. 6, unevenness 53 is formed on the smooth upper surface 55a of the mold material 55, which is the material of the mold body 51. As shown in FIG. 7, the unevenness 53 is processed by shot blasting, for example. That is, a large number of particles (media) M are sprayed from the injection nozzle N together with a fluid such as air or water onto the upper surface 55a, and the particles M are caused to collide with the upper surface 55a. As a large number of grains M collide with the upper surface 55a at high speed, the smooth upper surface 55a of the mold material 55 is depressed, the unevenness 53 is formed, and the mold body 51 is prepared.

As the particles used in the shot blasting described above, for example, particles made of stainless steel or iron can be adopted, and it is preferable that the particle size of the particles M is, for example, 0.2 mm or more and 0.3 mm or less. Further, the particles M used are not limited to the spherical shape but may be, for example, cylindrical. Furthermore, the particles M are not limited to having a uniform shape, but may be a mixture of different shapes. Note that particles M other than those exemplified above may be used depending on the material of the mold body 51, the surface roughness of the unevenness 53 to be formed (the uneven portion 15 of the contact member 11), and the like.

Further, the processing method for forming the unevenness 53 is not limited to using shot blasting. For example, the unevenness 53 may be formed by cutting the upper surface 55a of the mold material 55 using a processing tool such as a cutting tool.

In the outer frame member attachment step S12, the outer frame member 52 is attached to the mold body 51, as shown in FIG. In this outer frame member attachment step S12, for example, the outer frame member 52, which has been formed in a predetermined shape, is fixed onto the mold body 51 by various fixing means such as adhesion, welding, or bolting. As described above, since the thickness of the contact member 11 is determined by the thickness of the outer frame member 52, the thickness of the outer frame member 52 is strictly controlled. Through this outer frame member attachment step S12, the transfer mold TD is prepared. In addition, in this embodiment, although the form which uses the outer frame member 52 is mentioned as an example and is demonstrated, the form which does not use the outer frame member 52 may be sufficient. For example, in the material supply step S21 described later, the thickness of the contact member 11 can be controlled by adjusting the rotation speed of the transfer mold TD without using the outer frame member 52.

FIG. 8 is a cross-sectional view showing a state in which liquid dielectric material (pad forming material, contact member forming material) is supplied onto the transfer surface 51f of the transfer mold TD. FIG. 9 is a cross-sectional view showing a state in which the contact member 11 is created by solidifying the dielectric material on the transfer surface 51f. FIG. 10 is a sectional view showing a state in which the contact member 11 is taken out from the transfer surface 51f of the transfer mold TD. After manufacturing the transfer mold TD, in a contact member forming step S2, the contact member 11 is created using the transfer mold TD. As shown in FIG. 4, the contact member forming step S2 includes a material supply step S21, a material solidification step S22, and a contact member removal step S23.

In the material supply step S21, as shown in FIG. 8, a liquid dielectric material DM is supplied onto the transfer surface 51f of the transfer mold TD. The dielectric material DM is supplied from the opening 52a of the outer frame member 52 onto the inner transfer surface 51f. The dielectric material DM is supplied in an amount that is equal to or higher than the upper end of the outer frame member 52. In the material supply step S21, for example, a spin coater method may be used. The dielectric material DM is supplied by the dispenser D onto the transfer surface 51f. In the spin coater method, the transfer mold TD rotates around the central axis C, and the supplied dielectric material DM is spread on the transfer surface 51f by centrifugal force. By using the spin coater method, the dielectric material DM is uniformly spread on the transfer surface 51f. Note that in the material supply step S21, other methods and devices such as a spray coater may be used instead of the spin coater method. By using these devices, the contact member 11 can be formed to have a thin and uniform thickness. In the electrostatic adsorption device ED, the thinner the distance from the electrodes 12 and 13 to the contact surface 11f (that is, the film thickness of the contact member 11), the more the electrostatic adsorption force improves.

In addition, in the material supply step S21, in order to prevent air bubbles from remaining between the transfer surface 51f and the dielectric material DM, the transfer mold TD may be vibrated, or a microwave or the like may be applied to the dielectric material DM. may be irradiated. Moreover, in order to improve the wettability of the dielectric material DM on the transfer surface 51f, a lyophilic film may be coated on the transfer surface 51f.

The liquid dielectric material DM is supplied to the central portion of the transfer surface 51f. As the transfer mold TD rotates around the central axis C, the liquid dielectric material DM spreads toward the outer circumference on the transfer surface 51f. Further, the area in which the liquid dielectric material DM spreads is defined by the outer frame member 52. Therefore, by changing the height of the outer frame member 52, the desired film thickness can be easily changed. Further, even if an excessive amount of dielectric material DM is supplied onto the transfer surface 51f, the excess material will overcome the upper end of the outer frame member 52 and overflow to the outside of the outer frame member 52, so that the contact member 11 with a desired thickness can be is obtained.

In the material solidification step S22, the dielectric material DM supplied onto the transfer surface 51f is solidified. In order to solidify the dielectric material DM, not only may it be left in the atmosphere for a predetermined period of time to naturally dry, but also heating or the like may be performed under temperature conditions depending on the dielectric material DM. Further, in the material solidification step S22, the transfer mold TD may be housed in a chamber or the like set to a reduced pressure atmosphere and dried under reduced pressure. As shown in FIG. 9, by solidifying the dielectric material DM, a contact member 11 is created on the inside of the outer frame member 52 on the transfer surface 51f, to which the unevenness 53 of the transfer surface 51f is transferred.

In the contact member removal step S23, as shown in FIG. 10, the solidified contact member 11 is removed from the outer frame member 52 and transfer surface 51f of the transfer mold TD. The removed contact member 11 is formed with a contact surface 11f having an uneven portion 15 to which the unevenness 53 of the transfer surface 51f is transferred. The next contact member 11 can be created by supplying the liquid dielectric material DM again to the transfer mold TD after the contact member 11 has been taken out. That is, the transfer type TD can be reused.

Note that an electrode forming step of forming a pair of electrodes 12 and 13 on the boundary surface 11g of the contact member 11 is performed in a pre-step or a post-step of the contact member removal step S23. In this electrode forming step, a pair of electrodes 12 and 13 may be formed by pasting the electrodes 12 and 13 prepared in advance on the boundary surface 11g using an adhesive or the like, or a conductive paste may be used to form the pair of electrodes 12 and 13 on the boundary surface 11g. The pair of electrodes 12 and 13 may be formed by creating a pattern of the electrodes 12 and 13 and heating the contact member 11 to a temperature at which it does not melt. Through this electrode forming step, pad end portion AP1 is created. Further, a further dielectric layer (pad base AP2) is created on the pair of electrodes 12 and 13 to insulate the electrodes. The pad base AP2 is made of the same dielectric material DM as the contact member 11, and the method of making it is arbitrary. Alternatively, a pad base AP2 prepared in advance may be attached to the pad end AP1, or a liquid dielectric material DM may be supplied onto the pad end AP1 (above the pair of electrodes 12 and 13). A base AP2 may also be created. Through these steps, the suction pad AP is created. Thereafter, as shown in FIG. 1, the electrostatic adsorption device ED is manufactured by attaching the adsorption pad AP to the pad holding member PH.

The applicant conducted experiments and verification to evaluate the adsorption force of the electrostatic adsorption device ED as described above. The results will be explained. First, a transfer mold TD for forming the contact member 11 was manufactured. As the mold material 55 of the transfer mold TD, a material made of SUS material and having an outer diameter of 110 mm and a thickness of 2 mm was prepared.

Subsequently, the upper surface 55a of the mold material 55 was subjected to the following processing.
(Example 1)
An iron ball with a diameter of 0.2 mm was used as the granules M, and the granules M were injected onto the upper surface 55a of the mold material 55 at a pressure of 0.5 MPa to perform processing by shot blasting.
(Example 2)
A hard steel wire (WC material) with an average grain size of 300 μm was used as the grains M, and the grains M were injected onto the upper surface 55a of the shape material 55 at a pressure of 0.5 Mpa, and processed by shot blasting.

For comparison, a similar molded material 55 with the upper surface 55a subjected to the following processing was prepared.
(Comparative example 1)
A mirror finish was applied to the upper surface 55a of the mold material 55.
(Comparative example 2)
A hairline finish was applied to the upper surface 55a of the mold material 55.
(Comparative example 3)
Alumina with a count #60 was used as the granules M, and the granules M were injected onto the upper surface 55a of the mold material 55 at a pressure of 0.5 MPa, and processing was performed by shot blasting.
(Comparative example 4)
Alumina with a count #150 was used as the granules M, and the granules M were injected onto the upper surface 55a of the mold material 55 at a pressure of 0.5 MPa to perform processing by shot blasting.
(Comparative example 5)
A hard steel wire (WC material) with an average grain size of 500 μm was used as the grains M, and the grains M were injected onto the upper surface 55a of the shape material 55 at a pressure of 0.5 Mpa, and processed by shot blasting.

An outer frame member 52 was attached to each mold body 51 obtained in Examples 1 to 2 and Comparative Examples 1 to 5. The outer frame member 52 used had a rectangular shape of 105 mm and a thickness (height) of 80 μm. In Examples 1 to 2 and Comparative Examples 1 to 5, transfer mold TDs each having a transfer surface 51f were prepared.

Next, contact members 11 were created using the transfer type TDs of Examples 1 to 2 and Comparative Examples 1 to 5. First, silicone rubber is adopted as the dielectric material DM, and after supplying liquid silicone rubber onto the transfer surface 51f using a spin coater method, the transfer mold TD is pre-rotated, and then rotated at 1000 revolutions per minute for 30 seconds to transfer. The dielectric material DM was spread on the surface 51f to obtain the contact member 11 having a thickness corresponding to the thickness (height) of the outer frame member 52. Further, a pair of electrodes 12 and 13 were provided on the boundary surface 11g of the contact member 11 obtained. The pair of electrodes 12 and 13 had the same comb-tooth shape in Examples 1-2 and Comparative Examples 1-5. Thereafter, a pad base AP2 was made of silicone rubber on the pair of electrodes 12 and 13. The suction pad AP manufactured as described above was attached to the pad holding member PH.

(Surface roughness of contact surface)
Regarding the contact surface 11f of the suction pad AP of Examples 1 to 2 and Comparative Examples 1 to 5 obtained in this way, the arithmetic mean roughness Ra of the surface roughness, the maximum height roughness Rz of the surface roughness, and the surface The average length AR of the roughness motif in each roughness motif parameter was determined. For reference, also for the surface OBf of the cardboard container OB, the arithmetic mean roughness Ra of the surface roughness, the maximum height roughness Rz of the surface roughness, and the average length of the roughness motif in the motif parameters of the surface roughness. AR was calculated for each. The results are shown in Table 1.

(Evaluation of shear friction force)
Thereafter, the contact surface 11f of the suction pad AP was brought into contact with the upper surface of the cardboard container OB placed on the floor. The cardboard container OB used had a length of 385 mm, a width of 220 mm, a height of 180 mm, and a weight of 25 kg. In this state, a voltage of 6 kV was applied to the pair of electrodes 12 and 13 to electrostatically attract the cardboard container OB. After 15 seconds have elapsed since the electrostatic adsorption, the electrostatic adsorption device ED is moved horizontally at a speed of 40 mm/s, and the shear friction force generated between the adsorption pad AP and the cardboard container OB at that time. was measured with a push-pull gauge. The results are shown in Table 1.

As shown in Table 1, in Examples 1 and 2, the surface roughness (arithmetic mean roughness Ra, maximum height roughness Rz) of the uneven portion 15 is smaller than the surface OBf of the cardboard container OB. Further, in Examples 1 and 2, the maximum height roughness Rz of the surface roughness was 0.1 μm or more and 7.0 μm or less due to the uneven portion 15 formed on the contact surface 11f. Further, in Examples 1 and 2, the average length AR of the roughness motif in the motif parameter of the surface roughness of the uneven portion 15 was 90 or less. Further, in Examples 1 and 2, the average value of the difference in height between the concave portions 15a and the convex portions 15b of the uneven portion 15 was smaller than the surface OBf of the cardboard container OB.

Furthermore, as shown in Table 1, it was confirmed that Examples 1 and 2 had greater shear frictional force than Comparative Examples 1 to 5. Further, as shown in Table 1, in Comparative Examples 3 and 4 in which the shear friction force was less than 1.0, the value of the maximum height roughness Rz exceeded 7.0. In Comparative Example 5, which has the next lowest shear friction force, the value of the maximum height roughness Rz is not much different from Examples 1 and 2, but the value of the average length AR of the roughness motif in the motif parameter is 99.346. High compared to other examples. In Examples 1 and 2 and Comparative Examples 1 and 2, in which the shear friction force is as high as 2.88 to 3.57, the average length AR of the roughness motif in the motif parameter is 90 or less, and The value of the maximum height roughness Rz is 0.1 or more and 7.0 or less. In other words, if the average length AR of the roughness motif in the motif parameters is 90 or less, and the maximum height roughness Rz is 0.1 or more and 7.0 or less, it is possible to increase the shear friction force. It was confirmed that this is preferable (in order to increase the contact area with the surface OBf of the cardboard container OB). Further, in Examples 1 and 2 and Comparative Example 2 in which the shear friction force exceeds 3.0, the value of the maximum height roughness Rz is 1.0 or more and 5.0 or less. That is, it was confirmed that it is preferable that the value of the maximum height roughness Rz is 1.0 or more and 5.0 or less in order to further increase the shear frictional force. Further, in Comparative Examples 1 and 2, a decrease in shear friction force (adsorption force) was observed due to the adhesion of dirt on the surface OBf of the cardboard container OB. In particular, in Comparative Example 2, it was confirmed that the shear friction force was significantly reduced due to the adhesion of dirt. In contrast to Comparative Examples 1 and 2, it was confirmed that in Examples 1 and 2, there was no or small decrease in shear friction force due to the adhesion of dirt. In Examples 1 and 2, the value of the maximum height roughness Rz is 4.0 or more and 5.0 or less. In other words, if the value of the maximum height roughness Rz is 4.0 or more and 5.0 or less, even if dirt adheres to the surface OBf of the cardboard container OB, a decrease in shear friction force (adsorption force) can be avoided. This was confirmed to be favorable.

In addition, regarding the suction pad AP formed by the transfer type TD having the transfer surface 51f of Example 1 and the suction pad AP formed by the transfer type TD having the transfer surface 51f of Comparative Examples 2 and 3, the contact The surface 11f was observed using a microscope. The observed images are shown in FIGS. 11 to 13. FIG. 11 is an observed image of the contact surface 11f of the suction pad AP of Example 1. FIG. 12 is an observed image of the contact surface 11f of the suction pad AP of Comparative Example 2. FIG. 13 is an observed image of the contact surface 11f of the suction pad AP of Comparative Example 3.

As shown in FIG. 11, fine irregularities are irregularly formed on the contact surface 11f of the suction pad AP of Example 1. On the other hand, as shown in FIGS. 12 and 13, the contact surface 11f of the suction pad AP of Comparative Examples 1 and 2 does not have the uneven portion 15 as in Example 1. In addition, the unevenness 15 on the contact surface 11f of the suction pad AP in Comparative Example 3 (same as in Comparative Examples 4 and 5) has a higher density of unevenness than in Examples 1 and 2, and the difference between the concave and convex parts is higher than that in Examples 1 and 2. It was confirmed that the difference in height was also large.

(Comparative verification of electrode patterns)
Further, the patterns of the pair of electrodes 12 and 13 were studied, and the results will be explained. The following patterns were prepared for the pair of electrodes 12 and 13.
(Example 11)
A pair of comb-shaped electrodes 12 and 13 having three electrode portions 12b and 13b each having an electrode width of 10 mm and an electrode length of 45 mm were formed with a gap of 1 mm in between.
(Example 12)
Electrodes with an electrode width of 33 mm were formed with a gap of 1 mm in between.
(Example 13)
A pair of comb-shaped electrodes 12 and 13 having six electrode portions 12b and 13b each having an electrode width of 5 mm and an electrode length of 62 mm were formed with a gap of 1 mm in between.
(Example 14)
A pair of comb-shaped electrodes 12 and 13 having six electrode portions 12b and 13b each having an electrode width of 5.5 mm and an electrode length of 62 mm were formed with a gap of 0.5 mm between them.
For each of the electrodes 12 and 13 of Examples 11 to 14, the number of pairs of electrode parts 12b and 13b, the length (path length) of the gap d between the pair of electrodes 12 and 13, and the area of the pair of electrodes 12 and 13. are shown in Table 2.

For each of the electrodes 12 and 13 of Examples 11 to 14, the electrostatic attraction force FN and pressure PN per unit area were calculated using the following equations (1) and (2). In equations (1) and (2), W is the electrode width, L is the electrode length, d is the gap between the electrodes, V is the applied voltage, ε0 is the vacuum dielectric constant, and εr is the relative dielectric constant.

As a result, a calculated result was obtained that the electrostatic attraction force increases in the order of Examples 11 to 14. Comparing the calculation results with Table 1, it can be seen that the larger the number of pairs of electrode parts 12b and 13b, the larger the electrode area, and the narrower the gap d between electrodes 12 and 13, the lower the static electricity per unit area. It can be said that the electric power tends to be higher.

Subsequently, each of the electrodes 12 and 13 of Examples 11 to 14 was formed on the contact member 11 of Example 1 described above, and the shear friction force when adsorbing the cardboard container OB was evaluated. The results are shown in FIG. As shown in FIG. 14, compared to the case where the electrodes 12 and 13 of Examples 11 and 12 are provided, the shear per unit area is It was confirmed that the frictional force was significantly improved.

Although the embodiments and examples of the present invention have been described above, the technical scope of the present invention is not limited to the embodiments and examples described above. It will be apparent to those skilled in the art that various changes or improvements can be made to the embodiments and examples described above. Furthermore, forms with such changes or improvements are also included within the technical scope of the present invention. Furthermore, one or more of the requirements described in the above-described embodiments and examples may be omitted. Furthermore, the requirements described in the above-described embodiments and the like can be combined as appropriate. Furthermore, the steps shown in this embodiment can be executed in any order as long as the results of the previous step are not used in the subsequent step. Further, even if the operations in the above-described embodiments are described using "first", "next", "successively", etc. for convenience, it is not essential that they be performed in this order.

AP1... Pad end AP2... Pad base Cap... Center part OB... Cardboard container (object)
OBf...Surface DM...Contact member material ED...Electrostatic adsorption device M...Particle PH...Pad holding member TD...Transfer mold 11...Contact member 11f...Contact Surfaces 12, 13...Electrode 15...Irregularities 15a...Recesses 15b...Protrusions 51f...Transfer surface 52...Outer frame member 53...Irregularities

Claims (11)

a contact member made of a dielectric material and having a contact surface that can be deformed to follow the surface of an object;
a pair of electrodes capable of applying a voltage to the contact member,
The contact surface has an uneven portion in which concave portions and convex portions are continuous in one arbitrary direction along the surface and in both directions intersecting this one direction and crossing the surface,
In the electrostatic adsorption device, the contact surface is formed by being transferred using a transfer mold having a transfer surface formed by surface processing by shot blasting. The electrostatic adsorption device according to claim 1, wherein the pair of electrodes are provided in contact with the contact member and are deformable together with the contact member. The electrostatic adsorption device according to claim 1 or 2, wherein the contact surface has a surface roughness that is smaller than the surface roughness of the object. The electrostatic adsorption device according to any one of claims 1 to 3, wherein the contact surface has a maximum height roughness Rz of surface roughness due to the uneven portions of 0.1 μm or more and 7.0 μm or less. . The electrostatic adsorption device according to any one of claims 1 to 4, wherein the contact surface has an average length AR of a roughness motif in a motif parameter of surface roughness due to the uneven portions of 90 or less. Any one of claims 1 to 5, wherein the contact surface has an average difference in height between the concave portion and the convex portion in the uneven portion, which is smaller than the average value on the surface of the object. The electrostatic adsorption device described in . The electrostatic charge according to any one of claims 1 to 6, wherein the shear frictional force generated between the object and the contact surface when the surface of the object is attracted is 3.0 mN/mm2 or more. Adsorption device. A method for manufacturing a contact member that is included in an electrostatic adsorption device that adsorbs an object and has a contact surface that can be deformed to follow the surface of the object, the method comprising:
forming unevenness on the transfer surface of the transfer mold;
supplying a liquid dielectric material for forming the contact member onto the transfer surface and solidifying it;
A method of manufacturing a contact member, comprising: removing the contact member from the transfer surface. The method for manufacturing a contact member according to claim 8 , comprising forming the unevenness on the transfer surface by colliding particles with the transfer surface of the transfer mold. The method for manufacturing a contact member according to claim 9 , wherein the particles are made of SUS or iron and have a particle size of 0.2 mm to 0.3 mm. The transfer mold has an outer frame member on the outer peripheral side of the transfer surface, protruding upward from the transfer surface and surrounding the transfer surface,
The method for manufacturing a contact member according to any one of claims 8 to 10 , comprising supplying the liquid dielectric material inside the outer frame member.

Images