JP6936441B2 - Atmospheric pressure plasma device - Google Patents

Description

The present invention relates to an atmospheric pressure plasma apparatus that supplies a gas between counter electrodes, turns the gas into plasma, and then emits plasma from one electrode side to a target.

As an atmospheric pressure plasma device, the device described in Patent Document 1 is known as a device that emits plasma generated between counter electrodes toward a target.

The apparatus described in Patent Document 1 has parallel plate electrodes arranged one above the other. A high-frequency high voltage is applied to the electrodes arranged on the upper side, and the electrodes arranged on the lower side are electrically grounded. The facing surfaces of both or one of the electrodes are covered with a solid dielectric.
The gas supplied between the counter electrodes is turned into plasma by glow discharge, and is irradiated to the target through a slit formed in the ground electrode arranged on the lower side.

The apparatus of Patent Document 1 is provided with a cooling means for suppressing an increase in electrode temperature in order to stably supply plasma for a long period of time. As an example of the cooling means, it is possible to use a configuration in which a cooling water passage is formed inside the electrode and the cooling water flows through the passage, or a configuration in which the cooling water flows through the cooling pipe applied to the surface of the electrode. It is stated.

However, since these cooling means use cooling water in a place where a high voltage is applied, there is a risk of electric shock due to leakage of cooling water or dew condensation when low temperature cooling water is used, and for safety reasons. , Not preferable.
Further, if the cooling water is conductive, power loss due to electric leakage occurs through the cooling water. In order to suppress this power loss, it is possible to eliminate the conductivity of the cooling water by using an ion exchange resin, but there is a concern that the structure of the cooling means will be complicated and the cost of the cooling means will be high. ..

JP-A-2004-6211

A main object of the present invention is to provide an atmospheric pressure plasma apparatus provided with a new cooling means capable of solving various problems such as electric shock and electric leakage associated with the use of cooling water at once.

Atmospheric pressure plasma equipment
The first area where gas is supplied and
The second region, which is spatially separated from the first region,
A counter electrode provided in the first region, which turns the supplied gas into plasma and emits plasma from one electrode side to the outside of the device.
An opening formed in the second region and communicating with the inside and outside of the device,
An intake unit for sucking air in the second region is provided.
A part of the electrode is arranged in the second region.

With the above configuration, the air around the electrodes warmed by the heat generated by the electrodes is discharged to the outside of the device through the intake section, and new air enters the inside of the device through the opening due to the intake action at the intake section. Since it is introduced, it becomes possible to cool the periphery of the electrode. With this cooling method, the electrodes can be cooled without using cooling water, so that various problems such as electric shock and electric leakage associated with the use of cooling water can be solved at once.

To increase the cooling effect of the electrodes
The electrode is provided with heat radiation fins in the second region.

To further enhance the cooling effect of the electrodes
A hollow cylindrical guide member extending from the opening toward the electrode is provided in the second region.
It is desirable that an air flow from the opening to the intake portion is formed through the guide member as the intake is performed by the intake portion.

Regarding the routing of the feeder,
It is desirable that the guide member also serves as a passage for a feeding line for energizing the electrode.

As a concrete configuration,
The first region and the second region are formed in one chamber.
A partition member for separating both regions is provided in the chamber.
The partition member and the inner wall surface of the chamber form a flow path for gas supplied to the first region.

When providing a window for checking discharge between long counter electrodes in one direction,
It has a plurality of windows provided for visually recognizing the plasma generated between the counter electrodes from the outside of the apparatus.
It is desirable that the counter electrode is long in one direction and the window is arranged so as to sandwich the electrode center position in the length direction of the electrode.

The air around the electrodes, which is warmed by the heat generated by the electrodes, is discharged to the outside of the device through the intake section, and new air is introduced into the device through the opening along with the intake action at the intake section. It becomes possible to cool the periphery of the electrode.
Since the electrodes can be cooled without using cooling water in this cooling method, various problems such as electric shock and electric leakage associated with the use of cooling water can be solved at once.

Perspective view showing the whole atmospheric pressure plasma apparatus Cross-sectional view of the YZ plane when the atmospheric pressure plasma apparatus shown in FIG. 1 is cut at the center position in the X direction. Top view of the atmospheric pressure plasma apparatus shown in FIG. 1 when viewed from above. Top view of the atmospheric pressure plasma apparatus shown in FIG. 1 when viewed from below. Plan view when viewed from the AA line shown in FIG. Cross-sectional view of the XY plane when the atmospheric pressure plasma apparatus shown in FIG. 1 is cut at the central position in the Z direction. Perspective view showing another configuration example of the atmospheric pressure plasma apparatus Cross-sectional view of the XY plane when the atmospheric pressure plasma apparatus shown in FIG. 7 is cut at the center position in the X direction. Cross-sectional view showing another configuration example of the atmospheric pressure plasma apparatus

FIG. 1 is a perspective view of an atmospheric pressure plasma device according to the present invention. The X, Y, and Z axes shown are orthogonal to each other, and the relationship between these axes is common to other drawings described later.

The appearance of the atmospheric pressure plasma device 1 is roughly a rectangular parallelepiped shape, with a side wall 12 having open upper and lower surfaces, a lid 11 attached to the upper side of the side wall 12, and a lower side attached to the lower side of the side wall 12. It is composed of an electrode E2. Further, inside the lid 11, a hollow cylindrical guide member 5 is arranged along the inner wall of the lid 11.

In the configuration example of FIG. 1, holes communicating with each other inside and outside the device are formed on each surface of the atmospheric pressure plasma device 1 having a substantially rectangular parallelepiped shape. The holes formed on each surface will be briefly described.

The hole formed on the upper surface is an opening 2 for taking in outside air. The guide member 5 described above extends from the opening 2 toward the upper electrode E1 described later.
The hole formed on the side surface in the Z direction is a connection port 21 to which an intake unit 3 (for example, a circulator) for sucking air inside the device is connected. The holes formed on the lower surface are plasma emission ports such as slits and round holes (not shown) for emitting plasma from the lower electrode E2 toward the target. The hole formed on the side surface in the X direction is a supply port 13 for supplying gas, and another supply port is also formed on a surface opposite to the side surface on which the supply port 13 is formed, which is not shown. Has been done.

Hereinafter, the internal structure of the atmospheric pressure plasma device 1 described in FIG. 1 will be described with reference to FIGS. 2 to 6.

FIG. 2 is a cross-sectional view of a YZ plane obtained by cutting the atmospheric pressure plasma apparatus shown in FIG. 1 at the central position in the X direction. The groove G drawn by the alternate long and short dash line for diffusing the gas introduced from the intake unit 3, the gas supply unit 13, and the gas supply unit 13 drawn by the broken line is included in the cut surface shown in FIG. Although not, it is described for convenience to show the positional relationship of each part.

The inside of the atmospheric pressure plasma device 1 is roughly divided into two spaces. One is a first region R1 where plasma is generated, and the other is a second region R2 spatially separated from the first region R1.

The first region R1 is formed by a side wall 12, a partition member 7, a solid dielectric 15, and a lower electrode E2. Sealing means are provided between the members to maintain airtightness between the members. Specifically, the packing 14 maintains airtightness between the side wall 12 and the lower electrode E2 and between the partition member 7 and the fixed dielectric 15, and the O-ring 16 is between the partition member 7 and the side wall 12. The airtightness is maintained. The O-ring 16 is a holding ring 17 whose end is tapered from above, and is pressed against both sides of the side wall 12 and the partition member 7.

The second region R2 is formed of a side wall 12, a partition member 7, a solid dielectric 15, an upper electrode E1, and a guide member 5.
In FIG. 2, the solid dielectric 15 supported by the lower electrode E2 via the spacer I does not appear to be exposed in the second region R2, but it is not. By referring to FIGS. 4 to 6 described later, it can be understood that the solid dielectric 15 is partially exposed in the second region R2.

In FIG. 2, the second region R2 looks like a region divided into three, but the second region R2 shown is one spatially continuous region. Regarding this point, referring to FIGS. 4 and 6 showing different cut surfaces, there is a gap between the guide member 5 and the partition member 7, and the second one shown in FIG. 2 through this gap. It can be understood that the region R2 is a spatially continuous region.

A feeder line (not shown) is connected to the terminal fixing portion 6 of the upper electrode E1. The feeder is introduced into the guide member 5 from the outside of the device through the opening 2, and the end portion is fixed to the terminal fixing portion 6. A high frequency voltage is applied to the upper electrode E1 through this feeder.
As described above, since the guide member 5 also serves as a feed line passage, it is not necessary to process a part of the side wall 12 to provide a special feed line passage.

FIG. 3 is a plan view of the atmospheric pressure plasma device 1 shown in FIG. 1 when viewed from above. As shown in this figure, if the terminal fixing portion 6 of the upper electrode E1 is formed at a position where it can be visually recognized from the outside of the device, it is possible to visually confirm whether or not the feeding line is disconnected. Become.

FIG. 4 is a plan view of the atmospheric pressure plasma device shown in FIG. 1 when viewed from below. The lower electrode E2 shown is electrically grounded. The lower electrode E2 is formed with a single slit as the plasma emission port 22, but the configuration of the plasma emission port 22 is not limited to this.
For example, any shape such as a plurality of slits, a plurality of round holes, and a single round hole may be used as long as the plasma can be emitted from the lower electrode E2 toward the target.

FIG. 5 is a plan view when viewed from the line AA shown in FIG. An opening for fitting the upper electrode E1 is formed in the center of the partition member 7. The position of the upper electrode E1 on the ZX plane is fixed by being fitted into the opening.

When the upper electrode E1 is fitted into the partition member 7, a gap H is formed between the two members, but the lower part of the gap H is covered with the solid dielectric 15 drawn by the broken line. Region R1 and the second region R2 are not in communication with each other.

FIG. 6 is a cross-sectional view of the XY plane when the atmospheric pressure plasma device shown in FIG. 1 is cut at the central position in the Z direction. The supply port 13 for supplying gas and the connection port 21 to which the intake unit 3 is connected are described for convenience in order to represent the positional relationship.

The supply of gas to the first region R1 is performed through the groove G formed in the partition member 7. The groove G is formed on both sides of the partition member 7 in the X direction and has a groove extending downward from the gas supply port 13 as shown by the alternate long and short dash line in FIG.
By using such a groove G, it is possible to efficiently diffuse the gas over the entire area between the counter electrodes.
On the other hand, if the efficient diffusion of the gas is not taken into consideration, the shape of the groove G may be a shape extending straight downward from the gas supply port 13.

With the above-mentioned atmospheric pressure plasma device, the upper electrode E1 to which a high-frequency voltage is applied can be cooled without using cooling water, so that electric shock due to leakage of cooling water or dew condensation when low-temperature cooling water is used. There is no risk and it is highly safe.
Further, if the cooling water is conductive, power loss due to electric leakage occurs through the cooling water, but since the cooling water is not used, there is no such power loss.

With the above-mentioned atmospheric pressure plasma device, further effects can be expected in the following points.
Since the configuration is such that the gas is supplied only to the first region R1, the amount of gas used can be reduced as compared with the configuration in which the gas is supplied to the entire apparatus as in Patent Document 1.
Further, since the electrode is cooled by intake air, the heated heat around the electrode is sucked, and the temperature rise around the device can be suppressed. Moreover, since the dust inside the device can be sucked, it can be used without any trouble even in a clean room environment.
Further, since the first region R1 and the second region R2 are spatially separated, the flow of plasma irradiated to the target is not obstructed by the air flow for cooling the electrodes.

In addition to the embodiments described so far, the window W shown in FIGS. 7 and 8 may be attached to the side wall 12 of the apparatus. With such a window W, it is possible to visually recognize the state of plasma generated between the electrode pairs from the outside of the device.
The number of windows W may be a plurality as shown in the figure, or one may be provided at a specific location.

When the electrodes are long in the Z direction, it is desirable to arrange windows W on the left and right sides of the electrode center C in the same direction. With such an arrangement, the parallelism of the electrode pairs can be confirmed through the left and right windows W.
Regarding the mounting position of the window W, it is not necessary to mount the window W on the same side surface 12, but the left window W shown on one of the opposite side surfaces 12 is mounted and the right window W shown on the other side surface 12 is mounted. You may.

For example, if the upper electrode E1 is poorly attached and the right side is lower than the normal position in FIG. 8, the distance between the electrode pairs in the right side portion is narrower than that in the left side. There is a concern that the electric field will be concentrated and the solid dielectric 15 supporting the lower side of the upper electrode E1 will be damaged.
However, as described above, if windows W are provided on the left and right sides of the center C in the length direction of the counter electrode, the electrodes can be reattached if necessary after checking the parallelism of the electrode pair. Since it is possible, it is possible to prevent the solid dielectric 15 from being damaged.

In order to enhance the heat dissipation effect of the upper electrode E1, the heat dissipation fins 4 may be attached to the upper electrode E1 as shown in FIG. By providing the heat radiation fins 4, the cooling effect of the upper electrode E1 is improved.

When irradiating plasma at an angle other than perpendicular to the target, the atmospheric pressure plasma device 1 is rotated by a predetermined angle around the X-axis or Z-axis of FIG. 9, and the plasma is irradiated to the target. Become.
In this case, there is a concern that the upper electrode E1 and the partition plate 7 may be displaced by rotating the atmospheric pressure plasma device 1. As a countermeasure, as shown in FIG. 9, the end portion of the guide member 5 is brought into contact with the upper electrode E1 to fix the position of the upper electrode E1 in the Y direction.
Further, regarding the position fixing of the partition plate 7 in the Y direction, the holding ring 17 may be pressed from above by the fixing pin 18, or the partition plate 7 may be directly pressed by the fixing pin 18.
The fixing pin 18 is a member having a screw formed in a part of the pin, and is screwed into an insertion hole formed in the lid 11.

Although FIG. 9 has described the positional deviation of the electrodes and the like when the atmospheric pressure plasma device 1 is rotated, the guide member 5 and the fixing pin 18 may be used for adjusting the position of each part.
The posture of the fixed dielectric 15 is kept horizontal by the fixing pin 18 so that the solid dielectric 15 and the upper electrode E1 supported by the solid dielectric 15 are in close contact with each other, and then the upper electrode is used by the guide member 5. By pressing E1 against the fixed dielectric 15, both members are brought into close surface contact with each other.

Regarding the fixing pin 18, the position of each pin can be adjusted independently so that the vertical position of the plurality of fixing pins 18 shown in the drawing can be adjusted individually. Further, if it is desired to perform fine horizontal adjustment, the number of pins may be increased.
For example, in the case of a solid dielectric having a substantially rectangular shape, four fixing pins are provided so as to correspond to the center positions of the long side and the short side, and the inclination of the fixed dielectric in the long side and short side directions is adjusted. Then, it is conceivable to adjust the posture so as to obtain the desired posture.
On the other hand, the mounting posture of the lower electrode E2 that supports the solid dielectric 15 may be adjustable, and the posture of the fixed dielectric 15 may be adjusted.

With respect to the guide member 5, a plurality of mounting positions of the guide member 5 on the lid 11 side are provided, or a long hole is formed on the side surface of the lid 11 in the direction of moving the guide member 5 up and down, and the vertical position is adjusted. It is conceivable to configure the guide member 5 so that the position can be fixed at an arbitrary position.
Further, for positioning the upper electrode E1, it is convenient to fit the upper electrode E1 into the partition member 7 described with reference to FIG. When the upper electrode E1 is fitted into the partition member 7, the inner circumference of the electrode fitting hole of the partition member 7 is in a state where there is a very small gap between the two opposite sides, preferably all sides, of the outer periphery of the upper electrode E1. If it is formed as described above, the upper electrode E1 can be fitted into the electrode fitting hole to roughly determine the electrode position, and then the electrode position can be finely adjusted.

Since the lower electrode E2 is arranged on the outside of the device, the heat dissipation effect is higher than that of the upper electrode E1, and it is not necessary to provide a special cooling means. However, if measures are taken against the heat of the lower electrode E2, the lower electrode E2 may be made of a high melting point material that is not easily deformed by heat.

In the above embodiment, the guide member 5 is provided, but this member is a member for efficiently drawing the outside air into the upper electrode E1 through the opening 2, and it is not always necessary to provide the guide member 5.

The positional relationship between the opening 2 and the connection port 21 to which the intake unit 3 is connected may be reversed as described in the above embodiment. That is, the connection port 21 shown in each figure may be an opening 2 for taking in outside air, the opening 2 may be a connection port 21, and the intake unit 3 may be connected to the place that was originally the opening 2. Even with such a configuration, the effect of the present invention can be achieved.

In the present invention, a method of air-cooling the electrodes without using cooling water is used, but the electrodes may be cooled by flowing air through the passage of the cooling water used for cooling the electrodes. .. In this case, one end of the passage is an opening, and the intake portion is connected to the other end.

Regarding the intake speed in the intake unit 3, the temperature of the upper electrode E1 may be measured in real time, and the intake speed may be adjusted according to the measurement result.
Further, if there is a parameter (for example, plasma temperature) that can be correlated with the temperature of the upper electrode E1, the correlation is determined by conducting an experiment in advance, and the upper electrode is adjusted by adjusting the intake speed in the intake unit 3. By controlling the temperature of E1, the parameters correlated with the upper electrode E1 may be adjusted.
Furthermore, the values of the device parameters (temperature of the air taken in by the intake unit, the temperature of the upper electrode, etc.) when the plasma is normally lit are measured in advance, and the measurement is performed while the device is in operation. The normal lighting of the plasma may be determined by comparing with the device parameters.

In addition, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

1 Atmospheric pressure plasma device 2 Opening 3 Intake part 4 Heat dissipation fin 5 Guide member 6 Terminal fixing part 7 Partition member R1 First area R2 Second area E1 Upper electrode E2 Lower electrode G Groove W window

Claims (6)

The first area where gas is supplied and
The second region, which is spatially separated from the first region,
A counter electrode provided in the first region, which turns the supplied gas into plasma and emits plasma from one electrode side to the outside of the device.
An opening formed in the second region and communicating with the inside and outside of the device,
An intake unit for sucking air in the second region is provided.
A part of the electrode is arranged in the second region ,
A hollow cylindrical guide member extending from the opening toward the electrode is provided in the second region.
Along with the intake air at the intake unit, an air flow from the opening to the intake unit is formed through the guide member.
Further, an atmospheric pressure plasma device in which the guide member also serves as a passage for a feeding line for energizing the electrodes. The atmospheric pressure plasma device according to claim 1, wherein the electrodes are provided with heat radiation fins in the second region. The first region and the second region are formed in one chamber.
A partition member for separating both regions is provided in the chamber.
The atmospheric pressure plasma apparatus according to claim 1 or 2, wherein a flow path for gas supplied to the first region is formed between the partition member and the inner wall surface of the chamber. The first area where gas is supplied and
The second region, which is spatially separated from the first region,
A counter electrode provided in the first region, which turns the supplied gas into plasma and emits plasma from one electrode side to the outside of the device.
An opening formed in the second region and communicating with the inside and outside of the device,
An intake unit for sucking air in the second region is provided.
A part of the electrode is arranged in the second region ,
Further, it has a plurality of windows provided for visually recognizing the plasma generated between the counter electrodes from the outside of the apparatus.
An atmospheric pressure plasma device in which the counter electrode is long in one direction and the window is arranged so as to sandwich the electrode center position in the length direction of the electrode. The atmospheric pressure plasma device according to claim 4, wherein the electrodes are provided with heat radiation fins in the second region. It has a plurality of windows provided for visually recognizing the plasma generated between the counter electrodes from the outside of the apparatus.
The atmospheric pressure plasma apparatus according to any one of claims 1 to 3, wherein the counter electrode is long in one direction, and the window is arranged so as to sandwich the electrode center position in the length direction of the electrode.

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