JP3507898B1 - Static eliminator - Google Patents

Abstract

[PROBLEMS] To generate a stable glow discharge at atmospheric pressure,
Provided is a static eliminator that does not generate ozone and neutralizes the charge of a charged object requiring precise ion balance control. SOLUTION: A projection electrode 1 having a projection 11, a hollow electrode 2 having a small hole 21 provided opposite to the projection 11, and a power supply 41 for supplying a voltage to be applied to the projection electrode 1 are provided. This is a static eliminator that generates a stable glow discharge at atmospheric pressure to neutralize the charge of the charged object, and the voltage supplied by the power supply 41 is a sinusoidal alternating current having a DC bias component. Alternatively, it is a rectangular alternating current having a variable duty ratio with a pause time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static eliminator, and more particularly to a device for neutralizing the electric charge of a charged object by generating a stable glow discharge at atmospheric pressure.

[0002]

2. Description of the Related Art A glow discharge is a discharge that occurs through a gas having an extremely low pressure, for example, about 1 Torr, and when a high voltage is applied, a discharge current of about several mA to several tens of mA flows, and light emission called glow occurs. It is a discharge. Conventionally, it has been considered difficult to generate this glow discharge in a stable state at atmospheric pressure.

If electrification occurs in the industrial field, it may cause a production failure, explosion or fire. For example, in the manufacture of semiconductor devices and the like, devices are destroyed by electrostatic discharge due to charging of the devices, and fire and explosion are caused by electrostatic discharge due to charging of films and powders. A static eliminator is used to prevent this. The static eliminator generates positive and negative ions by some method,
Then, the ions having a polarity opposite to that of the charged object are made to collide with the charged object to neutralize the electric charge, thereby removing the electric charge. Conventionally, corona discharge and ultraviolet rays have been adopted as an ion source for generating ions, and a static eliminator using corona discharge is the mainstream. In the recent manufacture of devices sensitive to static electricity, more precise charge removal, for example, a charge level of ± 10 V or less, is required. However, in corona discharge, the discharge current is lowered and the distance from a charged object is usually reduced. Since this is achieved at a distance farther than that, there is a problem that the static elimination time becomes long. Also, 7k for corona discharge
Since a power supply of about V is required, there is a problem that damage to an object to be neutralized is large. When corona discharge is used, ozone is generated, and it is difficult to adjust the ion balance. In some cases, it was oppositely charged to the opposite polarity.

The present inventor previously provided a protruding electrode having a protruding portion, a hollow electrode having a small hole portion provided so as to face the protruding portion, and a power supply for supplying an alternating current applied to the protruding electrode. Proposed a static eliminator that neutralizes the electric charge of a charged object by generating a stable glow discharge at atmospheric pressure (Japanese Patent Application No. 2001).
-39999040). This static eliminator does not generate ozone, has a good ion balance, and neutralizes the charge of a charged object, but it has been difficult to use in a field where more precise ion balance control is required.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art, in which a stable glow discharge is generated at atmospheric pressure, ozone is not generated, and precise ion balance control is required. An object of the present invention is to provide a static eliminator that neutralizes the charge of a charged object.

[0006]

According to the present invention, there is provided a protruding electrode having a protruding portion, a hollow electrode having a small hole portion provided so as to face the protruding portion, and a power source for supplying a voltage applied to the protruding electrode. the provided, a static eliminator to neutralize the charge of the charged object by generating a stable glow discharge at atmospheric pressure, the ho
The size of the small hole of the raw electrode is 0.1 to 0.5 mm.
The closest distance between the protruding electrode and the hollow electrode is 0.2 mm or less.
Below, and the voltage supplied by the power supply is a static eliminator that is a sinusoidal alternating current with a DC bias component for controlling ion balance.

Further, the present invention comprises a protruding electrode having a protruding portion, a hollow electrode having a small hole portion provided facing the protruding portion, and a power source for supplying a current to be applied to the protruding electrode. A static eliminator for neutralizing the charge of a charged object by generating a stable glow discharge in atmospheric pressure, the hollow electrode
The size of the small hole part of is 0.1-0.5 mm.
The closest distance between the pole and the hollow electrode is 0.2 mm or less,
The voltage supplied by the power source is a static eliminator which is a rectangular wave pulse having a rest portion.

The present invention comprises a protrusion electrode having a protrusion, a hollow electrode having a small hole portion facing the protrusion, and a power supply for supplying a voltage applied to the protrusion electrode. A static eliminator for generating a stable glow discharge in an atmospheric pressure to neutralize the electric charge of a charged object, wherein the voltage supplied by the power source is a square wave pulse having a rest portion.

Further, the present invention is the static eliminator in which the width of the rectangular wave pulse has a positive / negative duty ratio of 4: 6 to 2: 8.

Further, the present invention is the static eliminator in which the rest portion of the rectangular wave pulse is 30 to 40% of one cycle.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described. An embodiment of the static eliminator of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram of a static eliminator according to the first embodiment. FIG. 2 is an explanatory diagram of applied voltages and the like in the static eliminator of the first embodiment. FIG. 3 is an explanatory diagram of an ion balance control result in the static eliminator of the first embodiment. FIG. 4 is an explanatory diagram of applied voltages and the like in the static eliminator of the second embodiment.

The first embodiment will be described. As shown in FIG. 1, the static eliminator of this embodiment includes a protruding electrode 1, a hollow electrode 2, a power supply 41, and a discharge stabilizing resistor 51.
Is equipped with. The protruding electrode 1 has a conical protruding portion 11. The hollow electrode 2 has a small hole portion (hollow) 21 facing the protrusion 11. The size d of the small hole portion 21 is
It is 0.5 mm or less, preferably 0.1 to 0.5 mm, and more preferably 0.3 mm. The thickness of the hollow electrode 2 is
It is about 0.1 mm. The closest distance between the protruding electrode 1 and the hollow electrode 2 is preferably 0.2 mm or less, more preferably 0.1 mm or less. The power supply 41 supplies a current applied to the protruding electrode 1. The applied voltage and the like will be described later. The discharge current can be adjusted by the power supply 41 and the discharge stabilizing resistor 51. The resistor 52 is connected to the discharge current I
It is for measurement of.

The applied voltage waveform and the like in the static eliminator of the first embodiment will be described with reference to FIG. The applied voltage is an alternating current (sine wave) having a direct current bias component, as shown by curves 61 to 63 of the discharge voltage, the discharge current, and the waveform of the power supply in FIG.
Consists of. The DC bias component is variable in order to control the ion balance, and is preferably −50 to −200V, and one example is −88V. Since the applied voltage has a peak voltage of about +600 to −800 V, it can be used as a low-voltage power supply as compared with the case of using corona discharge. In addition, the electrode heating due to the suspension of discharge is prevented, and the transition to arc discharge can be prevented. The result of ion balance control in this example is shown in FIG. In the present embodiment (DC bias component: -88V), the curve becomes 71, and the potential of the target becomes almost 0V when the discharge current to the target (object to be neutralized) is 0A, as compared with the case without DC bias (curve 72). It turns out that precise ion balance control is possible.

A second embodiment will be described. The static eliminator of this embodiment has the same configuration as that of the first embodiment (see FIG. 1). The applied voltage waveform and the like in this embodiment will be described with reference to FIG. The applied voltage or the like is a rectangular wave pulse having a quiescent portion, as shown by the curves 81 to 83 of the discharge voltage, discharge current, and power supply waveforms in FIG. The pulse width preferably has a positive / negative duty ratio of 4: 6 to 2: 8. If this ratio is adjusted, precise charge removal can be performed. The pause portion allows the discharge to be paused and prevents the transition to arc discharge due to cathode heating, 30-40% of the total pulse being suitable,
An example is 1/3. Since the applied voltage is about 600 V, it is a low voltage power source as in the first embodiment.

[0015]

According to the present invention, there is provided a static eliminator capable of generating a stable glow discharge at atmospheric pressure and generating no ozone, and neutralizing the charge of a charged object which requires precise ion balance control. Obtainable.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a static eliminator according to a first embodiment.

FIG. 2 is an explanatory diagram of applied voltage and the like in the static eliminator of the first embodiment.

FIG. 3 is an explanatory diagram of an ion balance control result in the static eliminator of the first embodiment.

FIG. 4 is an explanatory diagram of applied voltage and the like in the static eliminator of Example 2.

[Explanation of symbols]

1 protruding electrode 11 protrusion 2 hollow electrodes 21 Small hole 3 grid electrode 41 power supply 51 Discharge stability resistor 52 Current measuring resistor 61-63, 81-83 voltage-current waveform 71, 72 Static elimination ion current characteristics

Claims (4)

(57) [Claims] 1. A projection electrode having a projection, a hollow electrode having a small hole provided so as to face the projection, and a power supply for supplying a voltage applied to the projection electrode, which are stable under atmospheric pressure. Is a static eliminator for generating the glow discharge and neutralizing the electric charge of the charged object, and the size of the small hole of the hollow electrode is 0.1 to 0.5 mm.
And the closest distance between the protruding electrode and the hollow electrode is 0.2 m.
The static eliminator is less than or equal to m and the voltage supplied by the power source is a sine wave alternating current having a direct current bias component for controlling ion balance. 2. A projection electrode having a projection, a hollow electrode having a small hole provided so as to face the projection, and a power supply for supplying a current applied to the projection electrode, which are stable under atmospheric pressure. Is a static eliminator for generating the glow discharge and neutralizing the electric charge of the charged object, and the size of the small hole of the hollow electrode is 0.1 to 0.5 mm.
And the closest distance between the protruding electrode and the hollow electrode is 0.2 m.
A static eliminator characterized in that it is less than or equal to m and the voltage supplied by the power supply is a square wave pulse having a rest portion. 3. The static eliminator according to claim 2, wherein the width of the rectangular wave pulse has a positive / negative duty ratio of 4: 6.
A static eliminator having a ratio of up to 2: 8. 4. The static eliminator according to claim 2, wherein the rest portion of the rectangular wave pulse is 30 to 40% of one cycle.
A static eliminator characterized by being.