Electrostatic attraction device

Abstract

To provide an electrostatic attraction device capable of releasing a workpiece more stably.SOLUTION: An electrostatic attraction device 100 comprises an attraction part 21 which is applied with a voltage to electrically attract a workpiece W and a release acceleration part which accelerates releasing from the attraction part 21 when the workpiece W is released from the attraction part 21. The release acceleration part comprises: a deformation part 23 which causes the attraction part 21 to deform, wherein, for example, at least a part of a contact part for the workpiece W is flexible; and an excitation part 25 which excites the attraction part 21.SELECTED DRAWING: Figure 3A

Description

Technical Field

[0001] The present invention relates to an electrostatic adsorption device.

Background Art

[0002] Conventionally, an adsorption device is known that picks up a predetermined workpiece with an adsorption unit and then conveys it and releases it at a target position. Specifically, for example, a vacuum adsorption device as shown in Patent Documents 1 and 2 is known, which forms a negative pressure by sucking air with an adsorption unit and picks up the workpiece by the negative pressure.

[0003] However, such a vacuum adsorption device may pick up not only air but also foreign substances present around the workpiece, resulting in a possible decrease in the adsorption force. In addition, when the workpiece is extremely small, it may not be possible to form enough negative pressure to pick up the workpiece.

[0004] Therefore, for example, Patent Documents 3 and 4 describe an electrostatic adsorption device that electrostatically adsorbs a workpiece by applying a voltage. According to this configuration, even an extremely small workpiece can be picked up sufficiently.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the electrostatic adsorption devices according to Patent Documents 3 and 4, when the workpiece is extremely small, it may not be released due to the Coulomb force caused by the residual charge.

[0007] The present invention has been made in view of such circumstances. The object is to provide an adsorption part and an electrostatic adsorption device capable of stably releasing a workpiece.

Means for Solving the Problems

[0008] In order to solve the above problems, the invention according to claim 1 is an electrostatic adsorption device, an adsorption part that electrically adsorbs a workpiece by applying a voltage, and a release promotion part that promotes the release from the adsorption part when releasing the workpiece from the adsorption part.

[0009] The invention according to claim 2 is the electrostatic adsorption device according to claim 1, at least a part of the contact part with the workpiece in the adsorption part has flexibility, and the release promotion part includes a deformation part that deforms the adsorption part so that the area of the contact part is reduced.

[0010] The invention according to claim 3 is the electrostatic adsorption device according to claim 1, and the release promotion part includes a vibration part that vibrates the adsorption part.

[0011] The invention according to claim 4 is the electrostatic adsorption device according to claim 3, and the vibration part vibrates the adsorption part in a direction connecting the position of the adsorption part and the release position of the workpiece.

[0012] The invention according to claim 5 is the electrostatic adsorption device according to any one of claims 1 to 4, and the release promotion part includes a plurality of convex parts formed on the contact surface with the workpiece when an inverse voltage is applied to the adsorption part.

[0013] The invention according to claim 6 is an electrostatic adsorption device according to any one of claims 1 to 4, a drive unit configured to convey the adsorption unit from a first position to a second position; at the first position, a voltage is applied to the adsorption unit to electrically adsorb the workpiece, and at the second position, a control unit configured to stop applying a voltage to the adsorption unit or apply a reverse voltage to the adsorption unit to release the workpiece from the adsorption unit.

[0014] The invention according to claim 7 is an electrostatic adsorption device according to claim 6, wherein a suction unit for electrically sucking the workpiece by applying a voltage is provided at the second position, and the control unit applies a voltage to the suction unit when a reverse voltage is applied to the adsorption unit.

[0015] The invention according to claim 8 is an electrostatic adsorption device according to claim 6, wherein when releasing the workpiece from the adsorption unit, the control unit adjusts an angle of the adsorption unit with respect to the second position according to the center of gravity of the workpiece.

Advantages of the Invention

[0016] According to the present invention, the workpiece can be released more stably.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5

Figure 6

Figure 7A

Figure 7B

Figure 8

Mode for Carrying Out the Invention

[0018] Hereinafter, an electrostatic adsorption device according to an embodiment of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the illustrated examples. Also, in the following description, those having the same functions and configurations may be given the same reference numerals, and the description thereof may be omitted.

[0019] [Overall Configuration of Electrostatic Adsorption Device] [First Embodiment] FIG. 1 is a schematic view of an electrostatic adsorption device 100 according to the first embodiment. Also, FIG. 2 is a block diagram of the electrostatic adsorption device 100. As shown in FIG. 2, the electrostatic adsorption device 100 includes a drive unit 10, a transport unit 20, and a control unit 30. The electrostatic adsorption device 100 is a device that mainly transports a workpiece W placed on a mounting table S, which is a first position, to a release table R, which is a second position.

[0020] In the present embodiment, the mounting table S and the release table R may have an area larger than the area of the workpiece W and have a strength that allows the release of the workpiece W. Therefore, the configurations of the mounting table S and the release table R are not particularly limited.

[0021] (Workpiece) The work W is an object to be adsorbed that is conveyed by the conveying unit 20. The work W is, for example, an electronic component such as a multilayer ceramic capacitor, an inductor, a thermistor, and a module substrate, or a semi-finished product during the manufacture of an electronic component, and has a size of about 4 mm × 4 mm. However, the work W is not limited to electronic components or semi-finished products. Also, the size of the work W is not limited.

[0022] {Drive unit} The drive unit 10 is connected to the conveying unit 20 and drives the conveying unit 20. The drive unit 10 is, for example, an electromagnetic motor such as a DC motor, a servo motor, a stepping motor, and a linear motor, or an ultrasonic motor or compressed air. In particular, when the drive unit 10 is a stepping motor, the required amount of movement according to the size of the work W can be controlled by the number of steps, which is preferable.

[0023] (Conveying unit) An enlarged schematic view of the conveying unit 20 is shown in FIGS. 3A and 3B. The conveying unit 20 includes a suction unit 21, an electrode 22, and a deformation unit 23.

[0024] {Suction unit} The suction unit 21 is a sheet-like member formed of a predetermined dielectric and has flexibility and conductivity. When a voltage is applied to the electrode 22, positive and negative charges are generated on the suction unit 21 and the contact surface of the work W in contact with the suction unit 21, respectively. Then, the work W is adsorbed to the suction unit 21 by the electrostatic force (Coulomb force) of the positive and negative charges. In this way, the suction unit 21 is an electrostatic chuck that adsorbs the work W by electrostatic force.

[0025] {Electrode} The electrode 22 is connected to the suction unit 21 and applies a voltage to the suction unit 21 under the control of the control unit 30. The conveying unit 20 includes a first electrode and a second electrode as the electrode 22. The first electrode and the second electrode are connected to the suction unit 21 so as to have a predetermined interval as shown in FIGS. 3A and 3B.

[0026] The first electrode is connected to the anode of a power source (not shown). Therefore, the first electrode is charged with positive charges and functions as the positive electrode. Also, the second electrode is connected to the cathode of the power source. Therefore, the second electrode is charged with negative charges and functions as the negative electrode. By setting one as the positive electrode and the other as the negative electrode in this way, the potential difference between the first electrode and the second electrode can be increased. As a result, the adsorption force of the adsorption part 21 can be increased.

[0027] {Deformation part} When detaching the workpiece W from the adsorption part 21, the deformation part 23 reduces the contact area with the workpiece W by deforming the adsorption part 21. Thus, the deformation part 23 functions as a release promotion part that promotes the release of the workpiece W in the adsorption part 21.

[0028] Specifically, the deformation part 23 is, for example, a plate-shaped rod-shaped member located above the adsorption part 21 as shown in FIGS. 3A and 3B, and the upper part is fixed by a spring 23a. As shown in FIG. 3B, the deformation part 23 deforms the adsorption part 21 by pressing it with the biasing force of the spring 23a so that the adsorption part 21 bulges downward. Due to this deformation, the contact area between the adsorption part 21 and the workpiece W is reduced, and the releasability of the workpiece W in the adsorption part 21 is improved.

[0029] The deformation part 23 only needs to have a predetermined strength, and its configuration is not particularly limited. However, in order to reduce the possibility of short-circuiting when the deformation part 23 comes into contact with the adsorption part 21 to which a voltage is applied, it is preferably made of an insulator.

[0030] Also, the deformation part 23, which is a rod-shaped member, preferably has a configuration in which it presses and deforms the adsorption part 21 while applying a torsional operation. With such a configuration, the releasability of the workpiece W can be further enhanced.

[0031] {Control part} Returning to FIG. 2, the control unit 30 controls the adsorption and conveyance operation of the electrostatic adsorption device 100. The control unit 30 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), etc. Further, a storage unit including a ROM (Read Only Memory) in which an inkjet recording program and other information are stored is connected to the control unit 30. The adsorption and conveyance operation of the conveyance unit 20 is implemented by the CPU reading the program and data stored in the ROM and storing them in the RAM, and then executing the program.

[0032] [Adsorption and Conveyance Operation] The adsorption and conveyance operation by such an electrostatic adsorption device 100 will be described. First, the control unit 30 moves the adsorption unit 21 downward toward the mounting table S by driving the driving unit 10 and brings it into contact with the target workpiece W. The control unit 30 applies a voltage to the electrode 22 by driving the power supply to adsorb and hold the workpiece W on the adsorption unit 21. The control unit 30 moves the adsorption unit 21 in the vertical direction and in the front-rear, left-right directions by driving the driving unit 10 to convey and move the workpiece W to the release table R. The control unit 30 deforms the adsorption unit 21 by the deforming unit 23 so that the contact area with the workpiece W is reduced, and applies a reverse voltage to the electrode 22 to release the workpiece W.

[0033] [Effects of the First Embodiment] As described above, the electrostatic adsorption device 100 according to the present embodiment includes a deforming unit 23 that deforms the adsorption unit 21 so that the area of the contact portion with the workpiece W is reduced, as a release promoting unit that promotes the release of the workpiece W from the adsorption unit 21. According to this configuration, the Coulomb force between the adsorption unit 21 and the workpiece W can be reduced when the workpiece W is released, and the workpiece W can be released more stably.

[0034] [Modification Example of the First Embodiment] In the above description, the deformation part 23 is exemplified as a rod-shaped member, and a configuration in which the contact area with the workpiece W is reduced by pressing the suction part 21 downward, but the present invention is not limited to this. For example, as shown in FIG. 4A, the deformation parts 23, 23 connected to the left and right side surfaces of the suction part 21 may be configured to press the suction part 21 from both sides in the left and right directions so as to be deformed to protrude downward. With such a configuration, for example, even when the suction part 21 and the workpiece W are miniaturized, space constraints, durability constraints, etc. are not affected.

[0035] Further, in FIG. 3A, a configuration in which the electrodes 22 are connected to both ends in the left and right directions of the suction part 21 is exemplified, but the present invention is not limited to this. When the suction part 21 bends, if the electrode 22 is connected to the bending portion, there is a risk of dielectric breakdown. Therefore, as shown in FIG. 4A, the electrodes 22 may be connected to positions avoiding the bending portions of the suction part 21 to enhance the durability of the electrodes 22 against the bending of the suction part 21.

[0036] Alternatively, as shown in FIG. 4B, among the deformation parts 23, 23 connected to the left and right side surfaces of the suction part 21, one may be pulled upward to reduce the contact area between the workpiece W and the suction part 21 by a peeling action.

[0037] Further, when a voltage is applied, it may be configured to be deformed by providing the suction part 21 with a member that contracts and expands to its original size when the applied voltage is released.

[0038] [Second Embodiment] Next, the electrostatic chuck device 100A according to the second embodiment will be described with reference to FIGS. 5 and 6. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted. The electrostatic chuck device 100A of the second embodiment is different from the first embodiment in that, as shown in FIG. 6, the transport part 20 includes a base part 24 and the suction part 21 is provided below the base part 24. Further, a vibration part 25 such as a shaker or a vibration motor is provided on the base part 24.

[0039] When releasing the workpiece W, the control unit 30 vibrates the base unit 24 by the vibration unit 25, applies vibration to the workpiece W via the suction unit 21, and promotes the release. Thus, in the present embodiment, the vibration unit 25 functions as a release promotion unit.

[0040] In the present embodiment, it is preferable that the control unit 30 vibrates the suction unit 21 with the vibration unit 25 so as to have a frequency and amplitude corresponding to the characteristics (material, weight, contact area with the suction unit 21, shape (center of gravity position), etc.) of the workpiece W to be conveyed. For example, when the adsorption force of the workpiece W is large, it is preferable to vibrate the adsorption unit 21 at a higher frequency.

[0041] Further, the control unit 30 may vibrate the suction unit 21 with the vibration unit 25 so as to have a frequency and amplitude corresponding to the characteristics of the suction conveyance operation. For example, when it is desired to shorten the release time, it is preferable to vibrate the suction unit 21 with a higher amplitude.

[0042] In the present embodiment, it is more preferable that the control unit 30 vibrates the suction unit 21 with the vibration unit 25 based on the position of the suction unit 21 and the release position of the workpiece W. For example, although it is desired to release the workpiece W directly below the suction unit 21, if the suction unit 21 is vibrated in the shear direction parallel to the adhesion part of the workpiece W, the workpiece W is released at a position deviated from the target release position. Therefore, specifically, it is preferable to vibrate the suction unit 21 in the direction connecting the position of the suction unit 21 and the release position.

[0043] [Effect of the Second Embodiment] As described above, the electrostatic adsorption device 100A according to the present embodiment includes a vibration unit 25 that vibrates the suction unit 21 as a release promotion unit that promotes the release of the workpiece W from the suction unit 21. According to this configuration, the workpiece W can be stably released.

[0044] [Other Configurations] Although the above has been specifically described based on the embodiments of the present invention, the present invention is not limited to the above-described embodiments. Of course, various modifications are possible, including those within the scope of the invention described in the claims and its equivalent scope.

[0045] For example, in the above, the case where the electrostatic adsorption device 100 of the first embodiment and the electrostatic adsorption device 100A of the second embodiment include release promotion parts with different configurations was exemplified, but it is not limited to this. That is, for example, a configuration in which the adsorption part 21 is deformed while being vibrated by the deformation part 23, that is, an electrostatic adsorption device 100 that has both the configurations of the release promotion parts of the first embodiment and the second embodiment may be used.

[0046] Also, in the above, the deformation part 23 and the vibration part 25 were exemplified as the release promotion parts, but it is not limited to this. For example, as shown in FIG. 7A, when no voltage is applied, a plurality of convex parts are formed on the contact surface with the work W, and as shown in FIG. 7B, when a voltage is applied, particles that make the contact surface with the work W flat may be provided in the adsorption part 21 as the release promotion part. The particles are, for example, titanium oxide or the like. Also in this configuration, since the contact area between the work W and the adsorption part 21 can be reduced, the release of the work W can be promoted.

[0047] Also, in the above, it was stated that the configuration of the release table R is not particularly limited, but as shown in FIG. 8, a suction part R1 controlled by the control part 30 of the image forming apparatus 100B may be provided on the release table R.

[0048] The suction part R1 is provided near the placement surface of the work W. The suction part R1, like the adsorption part 21 of the transport part 20, has the application of voltage and the application of reverse voltage controlled under the control of the control part 30, and when voltage is applied, the contacting (placed) work W is electrostatically attracted.

[0049] In this configuration, the control unit 30 synchronizes the application (release) of a reverse voltage to the suction unit 21 of the transfer unit 20 with the application of a voltage to the suction unit R1 of the release table R. According to this configuration, the suction force of the suction unit R1 of the release table R can be made greater than the suction force of the suction unit R1 of the transfer unit 20, and the releasability of the workpiece W by the transfer unit 20 can be further enhanced.

[0050] Further, it is more preferable that the angle of the suction unit 21 be configured to be appropriately changeable by the control unit 30. When releasing workpieces W with different centers of gravity in the same manner, a deviation occurs in the release position according to the center of gravity of the workpiece W. Therefore, if the control unit 30 is configured to appropriately adjust the angle of the suction unit 21 with respect to the release table R according to the center of gravity of the workpiece W, the release position of the workpiece W can be controlled.

[0051] Also, in the above, a configuration in which each component of the electrostatic chuck device 100 is controlled by the control unit 30 provided in the electrostatic chuck device 100 has been illustrated, but it is not limited thereto. For example, a configuration in which each component of the electrostatic chuck device 100 is controlled by a device separate from the electrostatic chuck device 100 may also be used.

[0052] Also, in the above, the electrostatic chuck device 100 in which the transfer unit 20 conveys the workpiece W from the mounting table S to the release table R by the driving unit 10 has been illustrated, but it is not limited thereto. That is, for example, an electrostatic chuck device 100 in which the suction unit 21 only moves up and down to pick up and release the workpiece W at the same position may also be used.

[0053] Also, in the above, a configuration in which a reverse voltage is applied from the power source to the electrode 22 when releasing the workpiece W has been illustrated, but it is not limited thereto. That is, a configuration in which the driving of the power source is stopped and the application of the voltage to the electrode 22 is stopped may also be used.

[0054] Also, in the above, a configuration in which one electrostatic chuck device 100 includes one transfer unit 20 has been illustrated, but it is not limited thereto. That is, of course, a configuration in which one electrostatic chuck device 100 includes a plurality of transfer units 20 may also be used.

Explanation of Reference Numerals

[0055] 100 Electrostatic adsorption device 10 Driving part 20 Conveying part 21 Adsorbing part 22 Electrode 23 Deformation part 25 Vibration exciting part 30 Control part S Mounting table (first position) R Release table (second position) R1 Suction part W Workpiece

Claims

1. An electrostatic adsorption device comprising: an adsorption part that electrically adsorbs a workpiece by applying a voltage; and a release promotion part that promotes the release of the workpiece from the adsorption part when releasing the workpiece from the adsorption part.

2. At least a part of the contact part of the adsorption part with the workpiece is flexible, and the release promotion part includes a deformation part that deforms the adsorption part so that the area of the contact part is reduced. The electrostatic adsorption device according to claim 1.

3. The release promotion part includes a vibration part that vibrates the adsorption part. The electrostatic adsorption device according to claim 1.

4. The vibration part vibrates the adsorption part in a direction connecting the position of the adsorption part and the release position of the workpiece. The electrostatic adsorption device according to claim 3.

5. The release promotion part includes a plurality of convex parts formed on the contact surface with the workpiece when a reverse voltage is applied to the adsorption part. The electrostatic adsorption device according to any one of claims 1 to 4.

6. A drive part that transports the adsorption part from a first position to a second position; and a control part that applies a voltage to the adsorption part to electrically adsorb the workpiece at the first position, and stops applying a voltage to the adsorption part or applies a reverse voltage to the adsorption part to release the workpiece from the adsorption part at the second position. The electrostatic adsorption device according to any one of claims 1 to 4.

7. A suction part that electrically suctions the workpiece by applying a voltage is provided at the second position, and the control part applies a voltage to the suction part when applying a reverse voltage to the adsorption part. The electrostatic adsorption device according to claim 6.

8. The control part adjusts the angle of the adsorption part with respect to the second position according to the center of gravity of the workpiece when releasing the workpiece from the adsorption part. The electrostatic adsorption device according to claim 6. ​ ​ ​ ​ ​

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