JP2003300029A - Surface treating apparatus using atmospheric pressure plasma - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treating apparatus using atmospheric pressure plasma which has improved surface treating efficiency and carries out uniform surface treating by securing a large unit treating area while expanding the applicability of the apparatus by miniaturization of the apparatus. <P>SOLUTION: A pair of inner and outer discharge electrodes 2 and 3 which have acute projecting parts 2A and 3A for generating arch-shaped corona discharge are arranged at the central part and the outer circumference part of a gas flow passage 1. A swirling means 17 is provided at a place near a blow- off port 1A at the tip of the gas flow passage 1. The swirling means 17 imparts swirling force for diffusion to a gas introduced to a corona discharge region to thereby generate plasma-containing gas flow which is expanded diametrically and is formed in a nearly circular shape with large area and a diameter larger than that of the blow-off port 1A. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly makes the water repellency of a surface of a resin such as polyethylene, polypropylene, PTFE (polytetrafluoroethylene) or the like to be hydrophilic when coating or printing. The present invention relates to an atmospheric pressure plasma surface treatment apparatus used when performing surface treatment such as modification and cleaning of organic substances attached to the surface of glass, ceramics, metal, semiconductor and the like.

[0002]

2. Description of the Related Art As an atmospheric pressure plasma surface treatment apparatus of this type, as disclosed in, for example, Japanese Patent Application Laid-Open No. 6-163143, gas is applied while a high voltage is applied between a pair of discharge electrodes facing each other. By introducing a corona discharge that swells in an arch shape between the electrodes, plasma is generated around this corona discharge, and a gas stream containing the plasma is applied to the surface of the object to be treated to modify it. One configured to perform a surface treatment, and as disclosed in Japanese Patent Laid-Open No. 10-241827, a pair of inner and outer discharge electrodes are arranged in the central portion and the outer peripheral portion of a circular gas flow passage. There has been proposed a donut shape in which plasma is generated by corona discharge and a gas flow containing the plasma is blown toward the surface of the object to be treated.

[0003]

The conventional corona discharge type plasma surface treatment apparatus having the above-mentioned structure uses the ignition gas such as helium or hydrogen which is necessary in the case of the glow discharge type plasma surface treatment apparatus. There is an advantage that the processing cost can be reduced by improving the safety during use and saving the gas consumption. However, in the conventional corona discharge type plasma surface treatment apparatus, it is difficult to achieve both the requirement for this type of apparatus, that is, miniaturization and increase of the unit treatment area, that is, improvement of the surface treatment efficiency. Is. That is, if the entire device is downsized, it can be attached to a robot and the usage pattern of the device can be diversified, that is, the applicability can be expanded, but the unit processing area becomes smaller in proportion to the downsizing, and the surface treatment A decrease in efficiency is inevitable. On the contrary, if the unit treatment area is increased in order to increase the surface treatment efficiency, the surface treatment efficiency can be improved, but the size of the entire device is increased and the applicability due to mounting and use on the robot is naturally limited. However, there is a problem that the device cost becomes high.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to improve the surface treatment efficiency by securing a large unit treatment area while increasing the applicability of the apparatus by downsizing. It is an object of the present invention to provide an atmospheric pressure plasma surface treatment apparatus capable of performing uniform surface treatment.

[0005]

In order to achieve the above object, in an atmospheric pressure plasma surface treatment apparatus according to the present invention, a pair of inner and outer discharge electrodes are provided in a central portion and an outer peripheral portion of a circular gas passage. Corona discharge-producing sharp projections are formed in an opposed state at the tip outlets of the gas passage of the pair of inner and outer discharge electrodes or at positions immediately adjacent thereto, and the gas passage has an atmospheric pressure or an atmospheric pressure. By introducing a gas under a near pressure and applying a high voltage to the pair of discharge electrodes, an arc-shaped corona discharge is generated between the sharp projections facing each other, and the plasma generated by the corona discharge is included. An atmospheric pressure plasma surface treatment apparatus configured to perform a surface treatment by irradiating a surface of an object to be treated with a gas flow, wherein a portion of the gas flow path near the tip outlet port is provided with an introduction gas. Pivot means for imparting diffuser for swirling force and is characterized in that is provided.

Here, in the swirling means, as described in claim 2, as the plasma generated by the arch-shaped corona discharge rotates and moves around the central portion of the gas flow passage, the tip of the gas flow passage is formed. The gas blown out from the blowout port is configured to have a diameter larger than that of the tip blowout port and to be converted into a substantially circular flow.

According to the present invention having the above-mentioned structure, the tip projections of both electrodes are applied by applying a high voltage to the pair of inner and outer discharge electrodes while introducing the gas into the gas channel under atmospheric pressure or under a pressure near atmospheric pressure. A corona discharge that bulges like an arch between the parts is generated, and a gas flow containing plasma generated by this corona discharge is irradiated from the tip outlet of the gas flow path to the surface of the object to be processed, etc. Predetermined surface treatment is performed. At this time, the plasma generated by the arched corona discharge rotates around the central portion of the gas flow passage, while the gas introduced into the corona discharge plasma region from the gas flow passage is swung by the swirling means. Therefore, a gas flow having a diameter larger than that of the blowout port and having a substantially circular shape and covering a large area is generated. As a result, the diameter of the tip blow-out port can be reduced to reduce the overall size of the device, and the applicability can be expanded by mounting and using it on a robot, etc. It is possible to improve efficiency. Further, since the plasma region is also formed into a substantially circular shape, it is possible to make the plasma uniform over the entire treatment region and perform the predetermined surface treatment evenly and uniformly.

As the turning means in the above atmospheric pressure plasma surface treatment apparatus, as described in claim 3,
It is composed of a plurality of blade plates each formed in a spiral shape and arranged at equal intervals in the circumferential direction, and is composed of a rotating blade fixedly installed in the gas flow path separately from the pair of discharge electrodes. However, as described in claim 4, a plurality of protrusions protruding from the outer periphery of the cylindrical body are spirally wound to form a spiral gas guide groove between the adjacent spiral protrusions. It may be composed of a socket-shaped gas guide member arranged at the center of the gas flow path.

Further, in the above atmospheric pressure plasma surface treatment apparatus, the electric shock is prevented by covering the outer peripheral portion of the outer discharge electrode with a cover made of an electrically insulating material such as ceramic as described in claim 5. You can

Further, in the above atmospheric pressure plasma surface treatment apparatus, as described in claim 6, by coating a dielectric on at least the tip end surface of the pair of inner and outer discharge electrodes, corona discharge is converted into a dielectric barrier discharge. It is possible to reduce the discharge noise by making the plasma generated as a mild.

Further, in the above atmospheric pressure plasma surface treatment apparatus, as described in claim 7, the gas flow rate in the gas flow path can be adjusted, and / or the inside and outside, as described in claim 8. By configuring the frequency of the voltage applied to the pair of discharge electrodes to be adjustable, the gas flow rate and / or voltage can be adjusted to meet various conditions such as the distance between the outlet and the surface of the object to be processed and the property of the object to be processed. Therefore, appropriate and uniform plasma can always be generated by performing matching to perform a predetermined surface treatment accurately and efficiently.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a vertical cross-sectional view of an atmospheric pressure plasma surface treatment apparatus according to the present invention, FIG. 2 is an enlarged vertical cross-sectional view of a main part of FIG. 1, and FIG. 3 is a horizontal cross-sectional view taken along the line AA ′ of FIG. is there. In this atmospheric pressure plasma surface treatment apparatus, one discharge electrode 2 is arranged in the central portion of a circular gas flow passage 1, and the other cylindrical discharge electrode 3 is arranged in the outer peripheral portion of the gas flow passage 1. And a pair of these inner and outer discharge electrodes 2, 3
In addition, a high voltage with a maximum of 30 kV and a frequency of 10 to 100 kHz, a pulse frequency of 10 to 300 Hz, and a pulse duty of 0
The electrode rods 4 and 5 which apply at 100% are screwed and connected.

The outer peripheral surface of the electrode rod 4 screwed and connected to the central discharge electrode 2 is covered with an insulating sleeve 6 such as a heat shrinkable tube made of fluororesin, and the outer peripheral portion of the outer cylindrical discharge electrode 5 is It is covered with a cylindrical cover 7 made of an electrically insulating material, which is formed by cutting a ceramic such as alumina (Al ₂ O ₃ ). The electric insulating material 7 is detachably screwed to the lid member 8 that is brought into contact with the base end surface of the outer cylindrical discharge electrode 5 so as to close the base end portion of the circular gas flow path 1. ing. A cover member 12 having a gas storage space 11 in which a gas supply pipe 9 is connected by a connector 10 is fixedly connected to the lid member 8 via a screw member 13, and is circular with the gas storage space 11. A gas flow hole 14 connecting to the gas flow path 1 is formed so as to penetrate therethrough, and the electrode rods 4 and 5 are fixedly held by penetrating through the lid member 8 and the cover member 12, respectively. In addition, on the base end side of the cover member 12, the connector 10,
A cover 15 that surrounds the ends of the electrode rods 4 and 5 is fixedly connected via a screw member 16.

Protrusions 2A and 3A for generating corona discharge are formed in the radial direction inside and outside by free cutting at a portion of the pair of inner and outer discharge electrodes 2 and 3 corresponding to the tip outlet 1A of the gas passage 1. The pair of discharge electrodes 2, 3 are formed so as to face each other and introduce gas (described later) into the gas flow path 1 under atmospheric pressure or a pressure near atmospheric pressure through the electrode rods 4, 5.
By applying the above-mentioned high voltage to the above, a corona discharge that bulges in an arch shape is generated between the protrusions 2A and 3A that face each other inside and outside in the radial direction, and a gas flow containing plasma generated by this corona discharge is generated at the tip. It is configured to irradiate the surface of the object to be processed W from the air outlet 1A.

In the corona discharge type atmospheric pressure plasma surface treatment apparatus having the above-mentioned basic structure, the inside of the circular gas channel 1 near the tip outlet 1A is
As clearly shown in FIG. 2 and FIG. 3, it is composed of a plurality of blade plates 17A (about 3 to 8) each bent in a spiral shape and arranged at equal intervals in the circumferential direction. A swirl vane 17 for imparting a swirling force for diffusion to is fixedly installed on the insulating sleeve 6 on the outer peripheral surface of the electrode rod 4. In addition, dielectrics 31 and 32 such as ceramics are coated in a thin film shape on the surfaces of the pair of inner and outer discharge electrodes 2 and 3 which are bent and formed in an arc shape.

FIG. 4 is a system diagram of the gas supplied to the gas flow path 1, which includes an air supply path 20 connected to the compressor 18 and the pressure reducing valve 19, an inert gas such as argon and nitrogen, and oxygen and carbon dioxide. Of the reaction gas supply paths 21 and 22 of the solenoid valves 23, 24 and 25 and the needle valve 26, respectively.
The mixer 29 is connected via 27 and 28, and this mixer 29
The flow rate of the mixed gas mixed in 1. can be adjusted by the electromagnetic valve 30, and the mixed gas whose flow rate is adjusted is supplied to the gas storage space 11 via the gas supply pipe 9 and the connector 10, and from the gas storage space 11 It is configured to be introduced into the gas flow path 1 through the gas flow hole 14 at or near atmospheric pressure.

Next, the surface treatment operation by the atmospheric pressure plasma surface treatment apparatus configured as described above will be described. While introducing the mixed gas, the flow rate of which has been adjusted as described above in the gas supply system shown in FIG. 4, into the gas flow path 1 at or near atmospheric pressure, the pair of discharge electrodes 2 inside and outside through the electrode rods 4 and 5. , 3 to generate a corona discharge that bulges in an arch shape between the protrusions 2A and 3A of the electrodes 2 and 3 that face each other in the radial direction, and the plasma generated by this corona discharge. The gas flow containing the gas from the tip end outlet 1A of the gas flow path 1 to be processed W
A predetermined surface treatment such as irradiating the surface f to modify the surface f is performed.

At this time, the protrusions 2 facing each other inside and outside in the radial direction.
The plasma P generated by the corona discharge bulging in an arch shape between A and 3A rotationally moves around the central portion of the gas flow passage 1 to generate a substantially circular plasma region, while the plasma P from the gas flow passage 1 is generated. For the mixed gas introduced into the discharge plasma region, the swirl vanes 1 fixedly installed in the gas flow path 1
Since the swirling force for diffusion is given by 7, the gas blown out from the tip outlet 1A of the gas flow path 1 has a diameter larger than that of the tip outlet 1A and is substantially circular as shown by the phantom line in FIG. It will be converted into a gas flow g which has a shape and covers a large area. Therefore, while the diameter of the tip outlet 1A is reduced to reduce the size of the entire apparatus and the applicability of the apparatus to be attached to a robot is expanded, the plasma P is generated in a substantially circular region. By increasing the area of the gas flow g, it is possible to improve the surface treatment efficiency, and since the plasma P itself creates a substantially circular rotation region, the plasma P can be made uniform and a predetermined amount can be achieved. It is possible to perform surface treatment uniformly and appropriately.

Further, since the arc-shaped curved surfaces at the tips of the pair of inner and outer discharge electrodes 2 and 3 are coated with dielectrics 31 and 32 such as ceramics in a thin film form, the corona discharge becomes a dielectric barrier discharge. The generated plasma can be mildened and discharge noise can be reduced.

Further, since the gas supply system as shown in FIG. 4 is adopted, the outlet 1A and the surface f of the object W to be processed are.
By arbitrarily adjusting the gas flow rate in the gas flow path 1 and / or the frequency of the voltage applied to the pair of inner and outer discharge electrodes 2 and 3 in accordance with various conditions such as the distance from By appropriately matching various conditions, a proper and uniform plasma can always be generated, and a predetermined surface treatment can be performed accurately and efficiently.

In the above embodiment, a plurality of (about 3 to 8) spirals are provided inside the gas flow path 1 as a swirling means for imparting a swirling force for diffusion to the introduced gas, at a position near the tip outlet 1A. The swirl vane 17 including the circular vane plate 17A has been described as being fixedly installed, but instead of this, as shown in FIGS. 6 and 7, a plurality of ridges 33B protruding from the outer periphery of the cylindrical body 33A are provided. A spiral gas guide groove 3 is wound between spiral spiral protrusions 33B, 33B that are wound spirally and are adjacent to each other.
Socket-shaped gas guide member 33 formed by forming 3C
May be disposed in the central portion of the gas flow path 1 near the tip outlet 1A.

Further, in the above-mentioned embodiment, the gas flow passage 1 is described as being formed in a perfect circular shape. However, even if it is formed in an elliptical shape, the same operation and effect as above can be obtained. It is possible to play.

[0023]

As described above, according to the present invention, due to the presence of the swirling means for imparting the swirling force for diffusion to the introduced gas, the diameter of the tip outlet of the gas flow path can be reduced to reduce the size of the entire processing apparatus. The scope of plasma generation is almost circular, and the gas flow containing plasma is almost circular, while increasing the applicability by mounting on a robot and reducing the cost of the equipment. Since the surface area can be increased by diffusing the surface area, the surface treatment efficiency can be significantly improved. Moreover, since the swirling force is applied to the gas flow containing plasma, the plasma contained in the gas flow can be made uniform over a wide area, and the predetermined surface treatment can be performed appropriately and uniformly. There is an effect that can be.

In particular, as described in claim 6, by adopting a means for coating at least the tip end surface of the pair of inner and outer discharge electrodes with a dielectric, the corona discharge becomes a dielectric barrier discharge, and the corona discharge surrounds the corona discharge. The plasma generated can be mildened to reduce discharge noise.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an atmospheric pressure plasma surface treatment apparatus according to the present invention.

FIG. 2 is an enlarged vertical sectional view of a main part of FIG.

FIG. 3 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 4 is a gas supply system diagram in the atmospheric pressure plasma surface treatment apparatus.

FIG. 5 is an explanatory diagram of a generation state of a gas flow containing plasma over a large area.

FIG. 6 is an enlarged vertical cross-sectional view of a main part showing another embodiment.

FIG. 7 is a cross-sectional view taken along the line B-B ′ of FIG.

[Explanation of symbols]

1 circular gas flow path 1A tip outlet 2 Discharge electrode in the center 3 Discharge electrode on the outer periphery 2A, 3A Corona discharge generation protrusion 7 electrical insulation 17A spiral blade 17 swirl blades 33 Socket-shaped gas guide member 33A cylinder 33B spiral ridges 33C spiral gas guide groove W to be processed f Object surface

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01T 19/04 H01T 19/04 H05H 1/24 H05H 1/24 // C08L 101: 00 C08L 101: 00 F Term (reference) 3B116 AA46 AB23 BB32 BB36 BB87 BB88 4F042 AA01 BA13 BA21 DA05 4F073 AA01 BA07 BA08 BA16 CA01 CA04 CA07 CA08 CA13 CA21 CA24 CA26 CA27 CA61 HA01

Claims (8)

[Claims] 1. A pair of inner and outer discharge electrodes are disposed at a central portion and an outer peripheral portion of a circular gas flow passage, and the pair of inner and outer discharge electrodes are provided at a tip end outlet of the gas flow passage or at a position immediately adjacent thereto. The corona discharge generating projections are formed to face each other, and the gas is introduced into the gas channel under atmospheric pressure or a pressure close to the atmospheric pressure, and a high voltage is applied to the pair of discharge electrodes to face each other. Atmospheric pressure plasma surface configured to generate an arc-shaped corona discharge between the protruding parts and to irradiate the surface of the object to be processed with a gas flow containing plasma generated by the corona discharge. The atmospheric pressure plasma surface treatment apparatus is a processing apparatus, wherein a swirling means for imparting a swirling force for diffusion to the introduced gas is provided in a portion of the gas flow path near the tip end outlet. 2. The tip of the swirling means ejects gas blown from a tip outlet of the gas passage as the plasma generated by the arched corona discharge rotates around the central portion of the gas passage. The atmospheric pressure plasma surface treatment apparatus according to claim 1, wherein the atmospheric pressure plasma surface treatment apparatus is configured to have a diameter larger than that of the air outlet to convert the flow into a substantially circular flow. 3. The swirling means is composed of a plurality of vane plates each bent in a spiral shape and arranged at equal intervals in the circumferential direction, and is fixedly installed in the gas flow path separately from the pair of discharge electrodes. The atmospheric pressure plasma surface treatment apparatus according to claim 1 or 2, which is composed of a swirling blade. 4. The swirling means spirally winds a plurality of protrusions projecting from the outer periphery of the cylindrical body to form a spiral gas guide groove between adjacent spiral protrusions.
The atmospheric pressure plasma surface treatment apparatus according to claim 1 or 2, comprising a socket-shaped gas guide member arranged in the center of the gas flow path. 5. The atmospheric pressure plasma surface treatment apparatus according to claim 1, wherein the outer peripheral portion of the outer cylindrical discharge electrode is covered with an electrically insulating cover. 6. The atmospheric pressure plasma surface treatment apparatus according to claim 1, wherein at least the tip end surfaces of the pair of inner and outer discharge electrodes are coated with a dielectric. 7. The atmospheric pressure plasma surface treatment apparatus according to claim 1, wherein the gas flow rate in the gas flow path is adjustable. 8. The frequency of the voltage applied to the pair of inner and outer discharge electrodes is adjustable.
5. The atmospheric pressure plasma surface treatment apparatus according to any one of 1.