JP2003103487A - Electrostatic attraction manipulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic attraction manipulator capable of stably attracting an object to be attracted by low voltage. SOLUTION: At least one pair of mutually insulated electrodes 8a and 8b is provided. By arranging the object 2 to be attracted adjacently to respective surfaces of the electrodes 8a and 8b of a pair, a capacitor using the object to be attracted as a medium is formed between the electrodes 8a and 8b, and by applying a potential difference between the electrodes 8a and 8b, the object 2 to be attracted is attracted to an electrode by electrostatic force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic adsorption manipulator, and more particularly to an electrostatic adsorption manipulator suitable for adsorbing a minute lightweight object.

[0002]

2. Description of the Related Art Adsorption means using static electricity has been put into practical use for a long time as one of means for fixing recording paper of pen recorders and plotters.

For example, in Japanese Patent Publication No. 47-39392, a pen recorder, a plotter, etc. are fixed on a daily basis, electrostatically charged to form a skewed electrode structure relating to adsorption, and a voltage application means as a measure for eliminating charged electric charges. It is disclosed. It is also disclosed that the holding can be released easily by applying a reverse voltage.

Further, Japanese Unexamined Patent Application Publication No. 2001-1286 discloses a mechanism for gripping the microbeads to apply a high voltage only to a portion of the manipulator that comes into contact with the microbeads to charge the microbeads for adsorption. .

In addition, a means for maintaining the charge by devising the electrode in a substrate transfer mechanism of a vacuum device or the like, and a means for holding the electrode in a floating state have been disclosed.

However, in general, the adsorption method using charging has a problem that the adsorption force decreases with time.

[0007]

Therefore, a technical problem to be solved by the present invention is to provide an electrostatic attraction manipulator capable of stably attracting an object to be attracted at a low voltage.

[0008]

In order to solve the above technical problems, the present invention provides an electrostatic attraction manipulator having the following configuration.

The electrostatic attraction manipulator includes at least a pair of electrodes insulated from each other. The electrostatic adsorption manipulator forms a capacitor using the adsorbed material as a medium between the electrodes by disposing the adsorbed material adjacent to each of the paired electrodes, and a potential difference is created between the electrodes. When applied, the object is attracted to the electrode by electrostatic force.

In the above structure, when a capacitor having an adsorbate as a medium is formed and a potential difference is applied between the electrodes, an electric charge is accumulated on the electrodes, and even an unadsorbed adsorbate is electrostatically induced. As a result, in the portion to be adsorbed, an induced charge, which is opposite in polarity to the electrode, appears in the portion close to the electrode. Due to this induced charge, an attractive force is generated between the induced charge and the electric charge of the electrode, and the attracted force allows the object to be adsorbed to the electrode. If the material to be adsorbed has a high dielectric constant, even if the voltage between the electrodes is low,
An object to be adsorbed can be adsorbed and held.

In the above structure, the object to be adsorbed may be in contact with the electrode so as to be directly adjacent to the electrode, or indirectly adjacent to the electrode through a coating film formed on the surface of the electrode. Good. In the former case, the object to be adsorbed needs to be an insulator so that the electrodes are not short-circuited. In the latter case, if the coating on the electrode surface is an insulator, It is possible to adsorb even an object to be adsorbed.

Although the above-mentioned construction is an adsorption method using static electricity, it does not utilize conventional charging but uses the storage effect of a capacitor composed of a pair of electrodes through an object to be adsorbed. is there. By doing so, conventionally, it is possible to easily solve the problem that in the conventional charging, the charged electric charge disappears with time and the adsorption force decreases.

That is, in charging, the adsorbed material is charged by an electrostatic induction phenomenon by advancing a portion charged with static electricity and adsorbed by an electrostatic force, so that the charge of the adsorbed material disappears with time due to a neutralizing effect. And the adsorption power decreases. On the other hand, when the storage effect of the capacitor is used, since the voltage is constantly applied to the electrodes to store the charges, the spontaneous disappearance of the charges and the decrease in the attraction force due to the spontaneous disappearance do not occur.

Therefore, it is possible to stably adsorb the object to be adsorbed at a low voltage.

[0015] Preferably, it is provided with an adsorption releasing means for releasing the adsorption of the object to be adsorbed by setting the paired electrodes to the same potential.

In the above structure, the suction release means allows
When the paired electrodes are made to have the same potential, the electric charge stored in the paired electrodes disappears, and the induced charge inside the adsorbed material also disappears, so the attractive force disappears and the adsorbed material is absorbed. Can be released.

In the above structure, the adsorption releasing means may, for example, short-circuit the paired electrodes,
Same potential. Alternatively, when one of the paired electrodes is always grounded, the other electrode is grounded to have the same potential.

The electrostatic attraction manipulator of the present invention can be constructed in various ways.

As one aspect, the electrostatic attraction manipulator includes a rod-shaped inner electrode and a cylindrical outer electrode which is concentrically arranged at intervals along the outer peripheral surface of the inner electrode. The electrostatic adsorption manipulator arranges the object to be adsorbed adjacent to the end faces of the inner electrode and the outer electrode, the inner electrode is set to a positive potential, the outer electrode is set to a negative or earth potential, and the object is electrostatically charged. It is configured to be attracted to the end faces of the inner electrode and the outer electrode by force.

According to the above construction, the object to be adsorbed is arranged adjacent to the end faces of the inner electrode and the outer electrode, thereby forming a capacitor using the object to be adsorbed as a medium, and adsorbing the object to be adsorbed by electrostatic force. can do.

According to the above construction, the object to be attracted can be attracted to the tip (end face) of the electrostatic attraction manipulator, so that the attraction operation can be easily performed. Also. By setting the outer electrode to a negative or ground potential, it is less susceptible to external influences such as noise. In addition, electric shock can be prevented.

Preferably, the end surface has an end surface enlarged portion in which one or both of the outer electrode and the inner electrode extend.

According to the above structure, the distance (gap) between the outer electrode and the inner electrode becomes smaller at the end face due to the end face enlarged portion, so that the electric field between the outer electrode and the inner electrode is locally near the end face. Become stronger. As a result, the capacitance of the capacitor near the end surface using the adsorbed material as the medium is increased,
It is possible to obtain a sufficient attraction force with a low potential difference.

[0024] Preferably, there is provided adsorption releasing means for releasing the adsorption of the object to be adsorbed by setting the inner electrode and the outer electrode to the same potential.

In the above structure, if the inner electrode and the outer electrode are made to have the same potential, the electric charge stored in the inner electrode and the outer electrode disappears, and the induced charge inside the object to be adsorbed also disappears. Disappears and the holding of the adsorbed object can be released.

In the above structure, the adsorption releasing means is made to have the same potential by, for example, short-circuiting the inner electrode and the outer electrode. Alternatively, when the outer electrode is always grounded and has the ground potential, the inner electrode may be grounded to have the same potential.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION An electrostatic attraction manipulator according to an embodiment of the present invention will be described below with reference to FIGS.

First, the basic structure and principle of the electrostatic attraction manipulator of the present invention will be described.

As shown in the basic configuration diagram of FIG. 1, when the object to be attracted 2 is arranged between a pair of electrodes 6a, 6b connected to the DC power source 4 via the switches 8a, 8b, the electrodes 6a, 6b
Between 6b, it is possible to configure a condenser using the object to be adsorbed 2 as a medium.

When the switches 8a and 8b are in the positions shown in the drawing, the DC power supply 4 gives a potential difference between the electrodes 6a and 6b, and charges are accumulated in the electrodes 6a and 6b. As a result, even if the attracted object 2 is not charged, the electrodes 6a, 6
Inductive charges, which are opposite in polarity to the electrodes 6a and 6b, appear in a portion near b. An attractive force is generated between the induced charges and the charges of the electrodes 6a and 6b, and the attracted substance 2 can be adsorbed to the electrodes 6a and 6b.

On the other hand, when the switches 8a and 8b are at the positions opposite to those shown in the drawing, the electrodes 6a and 6b are short-circuited and the electrode 6
The charges of a and 6b are neutralized. Thereby, the electrodes 6a,
When the voltage difference between 6b disappears, the induced charge does not appear inside the object to be adsorbed 2 and therefore, the adsorption force does not occur between the object to be adsorbed 2 and the electrodes 6a and 6b.

Therefore, adsorption and desorption of the object to be adsorbed 2 can be performed depending on the presence or absence of a potential difference between the electrodes 6a and 6b.

That is, the capacitance C of a capacitor in which an object to be adsorbed is in contact with a pair of electrodes is determined by the dielectric constant of the object to be adsorbed and the contact area with each electrode.
That is, the capacitance C of the capacitor is as follows. C = ε ₀ × ε × S × 1 / d (1) where C: capacitance of the capacitor, ε ₀ : permittivity of vacuum,
[epsilon]: relative permittivity of the object to be adsorbed, S: contact area, d: average distance between electrodes.

When a DC voltage is applied to a capacitor composed of a pair of electrodes via an object to be adsorbed, an electric charge is accumulated, and the amount of stored electricity Q becomes as follows. Q = C × V (2) where Q is the amount of stored electricity, C is the capacitance of the capacitor, and V is the applied voltage.

In the capacitor, only the electric current corresponding to the charge transfer corresponding to the electrostatic capacity initially flows, so that the power consumption is extremely small.

The stored charges can be adsorbed because they are attracted to each other between the electrode and the object to be adsorbed. The attracting force f is as follows. f = Q ² × 1 / (4πε ₀ × ε) × 1 / d ² (3) Here, f is a force of attracting each other.

The electrostatic attraction manipulator can attract an object to be attracted by using this force. Formulas (1) to (3)
From the above, it can be seen that the larger the applied voltage, the smaller the distance between the electrodes, and the larger the dielectric constant of the substance to be adsorbed, the larger the adsorption force becomes.

The attraction force disappears by releasing the electric charge stored in the capacitor, and the adsorption of the adsorbed substance can be released.

Next, the electrostatic attraction manipulator 10 according to the first embodiment of the present invention will be described with reference to FIGS. 2 and 3.

As shown in the partial sectional view of FIG. 2A, the electrostatic chuck manipulator 10 has an electrode 12a on one side.
The substrate 14 on which .about.12d (12c and 12d are not shown) is arranged is supported by the supporting member 16 from the opposite side.

The electrodes 12a to 12d have the gaps 13a to 1d as shown in FIG. 2B when the substrate 14 is viewed from the electrode side.
3d are arranged so as to be separated from each other, and are connected to the conductors 18a and 18b (see FIG. 2A), respectively.

Each of the electrodes 12a to 12d is connected to a DC power source 20 via switches 22a and 22b, as shown in the electric circuit of FIG. The power supply voltage of the DC power supply 20 is
It is appropriately set according to the type, size, shape, etc. of the object to be adsorbed. When the switches 22a and 22b are in the positions shown, a potential difference is generated between the adjacent electrodes 12a to 12d,
When the switches 22a and 22b are in opposite positions, the electrode 1
2a to 12d are short-circuited with each other to eliminate the potential difference.

The electrostatic attraction manipulator 10 moves the attracted object so that the attracted object approaches or contacts both of the adjacent electrodes 12a to 12d, as indicated by broken lines 11a and 11b in FIG. 2B. Electrodes 12a to 12d, which constitute a capacitor as a medium, and to which an object to be adsorbed approaches or contacts
The object to be adsorbed can be adsorbed to the electrodes 12a to 12d by the potential difference between them, and the adsorption can be released by eliminating the potential difference.

Next, a concrete example will be described.

The substrate 14 has a thickness of 1 mm and a diameter of 18 mm.
The white plate glass of was used. Aluminum electrodes 12a to 12d having a thickness of 0.3 μm were formed on one surface of the substrate 14 by the RF magnetron sputtering method. Gap 13a-13d
Has a width of 1 mm.

With respect to the electrostatic adsorption manipulator 20 configured as described above, the voltage (adsorption voltage) required to be applied in order to adsorb an object to be adsorbed was examined.

The substrate 14 is horizontally arranged so that the electrodes 12a to 12d face upward, and the electrodes 12a adjacent to each other are arranged.
After applying a direct current voltage so that ~ 12d becomes positive and negative, an object to be adsorbed is placed on the electrodes 12a to 12d, and the substrate 14 is set to 9
The presence or absence of adsorption was examined by inclining vertically at 0 degree and checking whether or not the object to be adsorbed fell. When adsorbed, the application of the DC voltage was stopped, the electrodes 12a to 12d were short-circuited, and it was investigated whether or not the adsorption could be released well. Table 1 shows the experimental results obtained by examining three kinds of objects to be adsorbed, that is, a small piece of paper, a white plate glass, and a micro lens (a plano-convex lens having a flat surface and a convex surface with a radius of 1.0 mm) while changing the applied voltage.

[Table 1]

Both of the adsorbed substances were good in adsorption and release. Further, it did not stop adsorbing with time.

Next, an electrostatic attraction manipulator 30 according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5.

As shown in FIG. 4, in the electrostatic attraction manipulator 30, a cylindrical insulating member 34 is arranged on the outer side of a central member 32 which is a rod-shaped conductor, and a cylindrical outer member is arranged on the outer side thereof. The tubular member 36 is arranged. Outer cylinder member 36
Along the outer peripheral surface and one end surface of the conductive portion 38 (38
a, 38b) are formed.

As shown in the electric circuit of FIG.
Is connected to the negative side of the DC power supply 40 and is grounded.
The central member 32 is connected to the positive side of the DC power supply 40 via the switch 42. When the switch 42 is closed as shown, a potential difference is generated between the central member 32 and the conductive portion 38, and when the switch 42 is opened, the central member 32 is grounded and the central member 32 and the conductive portion 38 are grounded. The potential difference is eliminated.

The electrostatic attraction manipulator 30 is connected to the central member 32 in a state where the object to be attracted approaches or contacts both the end surface 32a of the central member 32 and the conductive portion 38b formed on the end surface of the outer tubular member 36. By applying a voltage to the conductive portion 38, the object to be adsorbed can be adsorbed to the end surface 32a and the conductive portion 38b. On the other hand, when the voltage application is released, the adsorption can be released.

As shown in FIG. 4, the end face 32a and the conductive portion 3 are formed.
A minute gap 33 is formed by the insulating member 34 with respect to 8b. The distance of the gap 33 is equal to the distance between the outer peripheral surface of the central member 32 and the outer peripheral surface of the outer tubular member 36.
Since it is smaller than the distance between the gap 8a and 8a, the strength of the electric field generated when a voltage is applied increases near the gap 33. Therefore, even if a high voltage is not applied to the central member 32 and the conductive portion 38, the attracted object is attracted to the tip (end face 32a and conductive portion 38b) of the electrostatic attraction manipulator 30 by the electric field concentrated near the gap 33. be able to.

Further, the conductive portion 38 on the outer peripheral surface of the outer tubular member 36.
By setting a to a negative or earth potential, the housing and the like of the device using the electrostatic attraction manipulator 30 and the conductive portion 3
It is possible to prevent the short circuit and the electric shock by making 8a the same potential.

Next, a concrete example will be described.

The outer cylinder member 36 has a diameter of 6 mm and a wall thickness of 1 m.
Using a glass tube of m, aluminum electrodes 38a, 38b having a thickness of 0.5 μm were formed on the outer peripheral surface and the end surface by the RF magnetron sputtering method. A copper rod having a diameter of 3 mm is used for the central member 32, a Teflon (registered trademark) tube is used for the insulating member 34, and the central member 32 is covered with the insulating member 34 to form a coaxial structure. It was inserted into the hollow hole.

With respect to the electrostatic adsorption manipulator 30 configured as described above, the voltage (adsorption voltage) that needs to be applied to adsorb an object to be adsorbed was examined.

A direct current voltage is applied so that the conductive portion 38, which is the outer electrode, is negative and the central member 32, which is the inner electrode, is positive, and then the end surface of the electrostatic attraction manipulator 30 is pressed against the object to be pulled up. Thus, the presence or absence of adsorption was examined. When the central member 32 is adsorbed, the central member 32 is grounded after disconnecting the DC voltage source, so that the central member 32 is electrically conductive.
It was set to the same potential as that of No. 8, and it was examined whether or not the adsorption could be released well. Table 2 shows the experimental results of three types of objects to be adsorbed: a small piece of paper, a white plate glass, and a minute lens (a plano-concave lens having a flat surface and a concave surface with a radius of 1.5 mm) while varying the voltage of the applied DC power supply. .

[Table 2]

In both cases, adsorption and release were good. Further, it did not stop adsorbing with time.

When a DC voltage was applied so that the outer electrode (conductive portion 38) was positive and the inner electrode (center member 32) was negative, the adsorption voltage became unstable (differs from measurement to measurement). It was From this, it can be considered that by setting the outer electrode to a negative or ground potential, it is less susceptible to external noise.

When the electrostatic attraction manipulator 30 is incorporated in a device, the housing of the device is generally negative or ground potential.

Therefore, it is preferable that the outer electrode (conductive portion 38) has a negative or ground potential and the inner electrode (center member 32) has a positive potential.

As described above, the electrostatic adsorption manipulators 10 and 30 can easily adsorb and release an object to be adsorbed. Further, since the adsorption can be performed at a low voltage and it is not necessary to supply a current to maintain the adsorption, the power consumption is small. Further, in the electrostatic attraction manipulator 30 of the second embodiment having the coaxial configuration, by applying a DC voltage so that the outer electrode has a negative or ground potential and the inner electrode has a positive potential, it is less likely to be affected by the outside. , Can be operated stably.

Since the electrostatic adsorption manipulators 10 and 30 electrostatically adsorb an object to be adsorbed at a relatively low voltage, the entire apparatus can be made compact and have a simple structure. It can be effectively used for handling microlenses and microchips, assembling work for micro substrates and micro devices.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

For example, the electrode (adsorption portion) of the electrostatic adsorption manipulator has a larger adsorption force along the outer shape of the object to be attracted, the closer it is to the object to be attracted and the larger the approaching area, the greater the attracting force. It is preferable to approximate the shape of the adsorbate, and an appropriate shape can be used according to the shape of the adsorbate.

Further, in the second embodiment, the outer electrode 38 is extended to form the end face enlarged portion 38b. However, like the electrostatic attraction manipulator 50 of FIG. 6A, the inner electrode 52 is replaced with the outer electrode 58. The end surface enlarging portion 52a extending toward the end surface enlarging portion 62a, 68a extending both electrodes 62, 68 as in the electrostatic attraction manipulator 60 of FIG. 6B.
You may make it the structure which has. The electrodes 52, 58; 6
Insulating members 56 and 66 are arranged between the two and 68.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of an electrostatic attraction manipulator of the present invention.

FIG. 2 is a configuration diagram of an electrostatic attraction manipulator according to the first embodiment of the present invention.

3 is an electric circuit diagram of the electrostatic attraction manipulator of FIG.

FIG. 4 is a configuration diagram of an electrostatic attraction manipulator according to a second embodiment of the present invention.

5 is an electric circuit diagram of the electrostatic attraction manipulator of FIG.

FIG. 6 is a configuration diagram of a modified electrostatic attraction manipulator.

[Explanation of symbols]

2 Adsorbate 6a, 6b electrodes 8a, 8b switch (adsorption release means) 10 Electrostatic adsorption manipulator 12a, 12b, 12c, 12d electrodes 22a, 22b switch (adsorption releasing means) 30 Electrostatic adsorption manipulator 32 Center member (inner electrode) 36 Outer cylinder member 38 Conductive part (outer electrode) 38a conductive part 38b Conductive part (end face expansion part) 42 switch (adsorption release means)

Claims (5)

[Claims] 1. A capacitor comprising at least a pair of electrodes insulated from each other, wherein an object to be adsorbed is arranged adjacent to each of the paired electrodes, and the object to be adsorbed is a medium between the electrodes. And an electric potential difference between the electrodes to adsorb the object to be adsorbed to the electrodes by an electrostatic force, which is an electrostatic adsorption manipulator. 2. The electrostatic adsorption manipulator according to claim 1, further comprising an adsorption releasing means for releasing adsorption of the object to be adsorbed by making the paired electrodes have the same potential. 3. A rod-shaped inner electrode, and a cylindrical outer electrode that is arranged concentrically along the outer peripheral surface of the inner electrode with a gap therebetween, and is provided on the end faces of the inner electrode and the outer electrode. Adjacent objects to be adsorbed are arranged so that the inner electrode has a positive potential and the outer electrode has a negative or earth potential so that the objects to be adsorbed are electrostatically attracted to the end surfaces of the inner electrode and the outer electrode. An electrostatic adsorption manipulator, which is characterized in that 4. The electrostatic attraction manipulator according to claim 3, wherein the end face has an end face enlarged portion in which one or both of the outer electrode and the inner electrode extend. 5. The electrostatic adsorption device according to claim 3, further comprising an adsorption releasing means for releasing adsorption of the object to be adsorbed by setting the inner electrode and the outer electrode at the same potential. manipulator.