JP2006210178A - Electrode device for plasma generation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure in which efficiency of contact of treated material with plasma active species is improved, and treatment efficiency of the treated material is improved by this in a device in which the plasma is generated from a gas and plasma treatment of the treated material is carried out. <P>SOLUTION: In an electrode device 30 for generating the plasma, the electrode device 30 is provided with a substrate 40 consisting of dielectrics, a first electrode 8 embedded in the substrate 40, and a second electrode 6A installed at one principal plane 7a of the substrate. A through hole 26 to supply plasma gas to the substrate 40 is formed in the substrate 40, and the plasma is generated by creeping discharge to occur along the substrate 40 from the second electrode 6A. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrode device for plasma generation used for applications such as sterilization of medical materials.

For example, a sheet used for packaging medical materials, medical waste, foodstuffs, etc. needs to be sterilized. As such a sterilization method, a method described in Patent Document 1 is known. In this method, plasma is generated at atmospheric pressure, and a sterilizing factor generated by the plasma is supplied from the plasma generator into the chamber. In the chamber, a predetermined sheet to be processed is transported on a transport roll and sterilized.
JP-A-10-129627

Moreover, in patent document 2, a sheet | seat is conveyed between a pair of discharge electrodes, a plasma is generated at atmospheric pressure, and a sheet | seat is plasma-processed. Patent Document 3 discloses a plasma discharge electrode having a porous portion. In the plasma generating electrode of Patent Document 4, a plurality of slit-shaped gas supply holes are provided in a disk-shaped electrode, and gas is ejected from the gas supply holes to generate a swirling flow. Further, in Patent Document 5, an induction electrode is provided inside a ceramic dielectric, a discharge electrode is provided on the surface of the dielectric, and creeping discharge is generated at the peripheral portion of the discharge electrode to generate positive ions and negative ions. Is described.
JP-A-6-265864 JP2003-334436 Japanese Patent No. 3154058 Japanese Patent No. 3403723

  However, the active species generated in the plasma often have a short lifetime, and are often extinguished in the gas before contacting the object to be processed and exhibiting the effect, so that the processing efficiency is low. For this reason, it is difficult to process a large amount of objects to be processed, and it is difficult to continuously process a plurality of objects to be processed. In particular, when the object to be processed is placed on the transport sheet and brought into contact with the plasma while being transported and processed, even if the area of the electrode is increased (even if the total length of the electrode is increased), Contact with the plasma-achieving species is performed only in a partial region on the electrode, and the processing efficiency of the object to be processed is lowered.

  An object of the present invention is to improve the efficiency of contact between an object to be processed and a plasma active species in an apparatus for generating a plasma from a gas to process the object to be processed, thereby improving the processing efficiency of the object to be processed. Is to provide such a structure.

  The present invention is an electrode device for generating plasma, which is a substrate made of a dielectric, a first electrode embedded in the substrate, and a second electrode provided on one main surface of the substrate. An electrode is provided, a through-hole is formed in the substrate, and plasma is generated by creeping discharge generated along the substrate from the second electrode.

  According to the present invention, an electrode is embedded in a dielectric substrate, a counter electrode is provided on the surface of the substrate, and a through hole is provided in the substrate. Since the gas activated by the plasma treatment lasts for a short time, it cannot be stored, and it is desirable to use it as close as possible to the location where the activated gas is generated. According to the present invention, a gas is allowed to pass through the through hole, and a creeping discharge is generated along the substrate surface from the edge of the electrode on the main surface of the substrate, and the gas is turned into plasma by the creeping discharge. Accordingly, a gas can be supplied by providing a through-hole at a desired location on the substrate, and a gas is desired by providing a second electrode in accordance with the flow of gas passing through the through-hole according to each through-hole and causing creeping discharge. It can be made into plasma at a location. As a result, the interval between the object to be processed on the substrate and the generation site of the active species of plasma can be shortened, and the plasma processing efficiency can be increased.

  In a preferred embodiment, the first electrode is embedded in the substrate so as not to be exposed in the through hole. This can prevent irregular discharge from the first electrode toward the inner wall of the through hole.

  The planar pattern of the second electrode (the third electrode as required) is not particularly limited. For example, as described later, it is preferable that the second electrode has a net shape or a comb shape. In the case where the second electrode has a net shape or a comb shape, it is preferable that the through holes be formed in a net shape or regularly formed in the gaps between the comb teeth. In this embodiment, the shape of the mesh is not particularly limited, and may be a circle, an ellipse, a racetrack shape, a quadrangle, a polygon such as a triangle, or the like. The shape of the comb-teeth of the comb-like electrode is not particularly limited, but is preferably a rectangle or a parallelogram.

  In the present invention, the second electrode can be provided at a position facing the object to be processed. In this case, plasma can be generated by creeping discharge from the edge of the second electrode, and this plasma can be brought into contact with the object to be processed. However, the present invention is not limited to this form, and the second electrode can be formed on the main surface (back surface) side of the substrate that does not face the object to be processed. In this case, gas is turned into plasma by creeping discharge from the edge of the second electrode, and the generated plasma is supplied to the object to be processed through the through hole.

  In a preferred embodiment, a third electrode is provided on the other main surface of the substrate, and plasma is generated by creeping discharge generated along the substrate from the third electrode. As a result, plasma can be generated on both sides of the substrate with respect to the through hole, so that the processing efficiency of the object to be processed is further improved.

  In a preferred embodiment, there is an exposed region in which the main surface of the substrate is exposed between the second electrode (pushing the third electrode if necessary) and the through hole, and along the main surface in this exposed region. Creeping discharge occurs. When creeping discharge is generated along the main surface of the substrate in this manner, the distance between the plasma generation site and the object to be processed can be minimized, so that the processing efficiency of the object to be processed is further increased.

  In addition, the object to be processed can be fixed and batch-processed. However, from the viewpoint of processing efficiency, it is preferable to perform plasma processing while the object to be processed is conveyed by the conveying means. This conveying means will be described later.

The processing target according to the present invention is not particularly limited as long as it can be plasma-processed.
(1) Treatment process Surface modification of the treatment object (hydrophilic treatment: hydrophilic treatment of the treatment object surface before applying the adhesive or paint to the treatment object to improve wettability, adhesion of colorant or paint , Sterilization or sterilization treatment, organic substance removal / organic substance decomposition treatment, gas modification treatment, purification treatment of harmful gas components (2) Products to be treated Resin (polyethylene, polypropylene, polystyrene, polyimide, tetrafluoro) Ethylene, etc.), ceramics, metal, glass Medical instruments and medical materials (blister pack, blister pack sheet, syringe, syringe gasket, vial rubber stopper, injection needle, gauze, non-woven fabric, etc.)
Food packaging sheet Semiconductor wafer, liquid crystal glass substrate, plasma treatment of ceramics

Hereinafter, more detailed embodiments of the present invention will be described with reference to the drawings.
FIG. 1A is a cross-sectional view schematically showing an electrode device 30 for plasma generation according to one embodiment of the present invention, and FIG. 1B is an electrode device for plasma generation according to another embodiment. It is a cross-sectional view schematically showing 30A.

  In the plasma generating electrode device 30 of FIG. 1A, the substrate 40 is made of a dielectric material and includes a surface layer portion 7 and a base portion 9. A first electrode 8 having a predetermined pattern is embedded in the substrate 40, and a through hole 26 is formed at a predetermined location. In this example, the edge of the electrode 8 is covered with a dielectric so that the edge of the electrode 8 is not exposed to the inner wall surface of the through hole 26, and a predetermined insulation interval is maintained. A second electrode 6A is provided on the main surface 7a of the substrate 40, and the electrode 6A and the embedded electrode 8 face each other. The substrate 40 is separated by an electrode 8 into a dielectric layer 9 on the main surface (back surface) 9a side opposite to the dielectric layer 7 on the main surface 7a side. When gas is supplied to the through hole 26 as indicated by arrow A, the gas flows from the outlet of the through hole 26 along the substrate surface as indicated by arrow B. At this time, a creeping discharge D is generated from the edge of the electrode 6A toward the exposed region 41 to generate plasma. The object to be processed is installed in the space on the electrode 6A or the object to be processed is transported.

  In the apparatus 30A of FIG. 1B, a third electrode 6B is further formed on the other main surface (back surface) 9a, and the electrode 6B also sandwiches the dielectric layer 9 with respect to the embedded electrode 8. Opposite. Then, creeping discharge is generated as indicated by an arrow D from the edge of the electrode 6B toward the exposed region 41 of the main surface 9a. As a result, a part of the gas is turned into plasma by the creeping discharge D and then supplied toward the object to be processed as indicated by an arrow A through the through hole 26.

  When manufacturing such devices 30 and 30A, for example, a substrate 31 as shown in FIGS. 2A and 2B is manufactured. Here, in FIG. 2A, the electrode 8 is embedded in the substrate 31, and the electrode 6A is formed on the main surface 7a. In FIG. 2B, the electrode 8 is embedded in the substrate 31, and the electrode 6A is formed on the main surface 7a and the electrode 6B is formed on the main surface 9a. In this state, by forming the through hole 26 at a desired location so as not to pass through the electrode 8, each plasma generating electrode device shown in FIGS. 1A and 1B is obtained.

  Here, the dielectric material constituting the substrate is not particularly limited, but ceramics are preferable, and alumina, magnesia, zirconia, silicon oxide, mullite, spinel, cordierite, aluminum nitride, silicon nitride, titanium-barium-based oxide are particularly preferable. Barium-titanium-zinc oxide is preferable. Moreover, the material of each of the first, second and third electrodes is not particularly limited, and any material having a predetermined conductivity can be used. For example, tungsten, molybdenum, manganese, titanium, chromium, zirconium, nickel, silver, iron, copper, platinum, palladium, or an alloy thereof is preferable.

  The substrate 31 as shown in FIGS. 2A and 2B can be manufactured by a so-called green sheet lamination method. That is, when the dielectric powder such as ceramics is press-molded, a metal plate or a metal foil constituting the embedded electrode can be embedded and then sintered. The embedded electrode can also be formed by applying a paste on the ceramic molded body. As a coating method in this case, any coating method such as screen printing, calendar roll printing, dipping method, vapor deposition, physical vapor deposition method and the like can be used. The second and third electrodes can also be easily formed by a coating method. When the electrode is formed by a coating method, the above-mentioned various metal or alloy powders are mixed with an organic binder and a solvent (such as terpineol) to prepare a conductor paste, and then this conductor paste is applied onto the ceramic green sheet. Work. The second electrode and the third electrode can also be formed by coating and baking on the main surface of the substrate 31 made of a ceramic sintered body.

When the substrate 31 is manufactured, the method of forming the ceramic green sheet is not particularly limited, and any method such as a doctor blade method, a calendar method, a printing method, a roll coater, or a plating method can be used. In addition, as the raw material powder of the green sheet, the above-described various ceramic powders and powders such as glass can be used. At this time, examples of the sintering aid include silicon oxide, calcia, titania, magnesia, and zirconia. It is preferable to add 3 to 10 parts by weight of the sintering aid with respect to 100 parts by weight of the ceramic powder. Known dispersing agents, plasticizers, and organic solvents can be added to the ceramic paste.
The substrate 31 can also be made by a powder press molding method, and when a mesh metal or metal foil is used for the electrode to be embedded, a sintered body in which the electrode is embedded by a hot press method can also be obtained.
By appropriately selecting the molding aid, the molded body of the substrate 31 can be produced even by extrusion molding. By appropriately selecting a solvent on the surface of the extruded molded body, an electrode can be formed by printing or the like with a metal paste serving as a conductive film component.

  The porosity of the obtained substrate 31 is not particularly limited, but can be 0.1 to 35%, and more preferably 0.1 to 10%.

  The second electrode and the third electrode can be exposed to the space. Alternatively, the second and third electrodes can be covered with a protective film made of a dielectric. Examples of the dielectric include ceramics and glass. Examples of ceramics include alumina, zirconia, magnesia, silicon oxide, mullite, spinel, cordierite, aluminum nitride, silicon nitride, titanium-barium oxide, barium-titanium-zinc oxide.

  The formation method of each through-hole is not specifically limited. In a preferred embodiment, after the substrate 31 as shown in FIGS. 2A and 2B is produced by sintering, through holes are formed in the substrate 31 by ultrasonic machining or cutting. Alternatively, at the stage of the green sheet before the substrate 31 is sintered, through holes can be formed in the green sheet by knife cutting (punching with a mold), and then the green sheet can be sintered.

  The arrangement density and arrangement pattern of the through holes are not particularly limited. For example, in consideration of the lifetime of the activation gas and the processing amount of the object to be processed, the through hole can be provided only on the entrance side (upstream side) of the apparatus, or can be provided over the entire main surface of the substrate. In the case of an activated gas containing an activated species having a relatively long lifetime (for example, when the activated species is ozone gas), the treatment target can be processed for a sufficiently long period of time even if a through hole is formed in the substrate only on the upstream side of the apparatus. Objects can be brought into contact with the activation gas. However, when the lifetime of the active species is short, it is preferable to form a through hole on the entire surface of the substrate.

The arrangement density (number) of through holes and the size of the through holes are determined according to the reaction rate with the object to be processed and the amount of the object to be processed. In sterilization applications, for example, through holes can be placed over the entire surface of the substrate to remove up to 10 ⁶ cfu. In the case of sterilization up to 10 ⁴ cfu for sterilization, 70 to 80% of the number of through holes necessary to achieve 10 ⁶ cfu is sufficient. In this way, the density and number of through holes can be determined according to the usage situation.

  In the present invention, the planar pattern of each of the first, second, and third electrodes is not particularly limited, and can be designed according to the type, lifetime, and generation amount of active species in the plane. For example, the planar pattern of the electrodes can be comb-like or mesh-like.

  For example, FIG. 3 is a plan view schematically showing a pattern example of the second electrode 6A. In this example, a mesh electrode 6A is formed on the substrate surface. Each mesh 32 is, for example, a quadrilateral, and a through hole 26 is formed in each mesh 32. In such a form, creeping discharge is generated in each mesh, and the gas supplied from the through-hole 26 corresponding to each mesh can be turned into plasma. The first electrode inside the substrate also needs to have a mesh pattern facing the electrode 6A. The third electrode may also have a planar pattern as shown in FIG.

  Thus, when the planar pattern of an electrode is made into mesh shape, the pitch of a creeping discharge location can be changed suitably by changing the pitch (interval) of each mesh. This is because creeping discharge occurs at the edge of each mesh. Therefore, when the lifetime of the active species is short, the number of creeping discharge points can be increased by reducing the mesh pitch. The mesh pitch is not limited because it is designed according to the type of active species, but is preferably 100 μm (0.1 mm) or more, and more preferably 500 μm (0.5 mm) or more. . From the viewpoint of generating active species uniformly over a wide range, the mesh pitch is preferably 20 mm or less, and more preferably 3 mm or less.

  As shown in the schematic perspective view of FIG. 4, the apparatus of FIG. 3 includes a lower dielectric layer 9, an upper dielectric layer 7, and a first electrode embedded between the dielectric layers 7 and 9. 8, and a mesh-like second electrode 6 </ b> A is formed on the main surface 7 a on the upper dielectric layer 7 side.

  Further, for example, in the device 30C shown in FIG. 5, a comb-like second electrode 6A is formed. In this example, the comb-like electrode 6A is formed on the substrate surface. The comb-like electrode 6A includes an elongated common electrode 43 and a plurality of rows of elongated comb-tooth portions 44 protruding from the common electrode. An elongated exposed portion 45 is formed between adjacent comb teeth portions 44, and a predetermined number of through holes 26 are formed in each exposed portion 45. In such a form, creeping discharge is generated in the vicinity of the edge of each comb tooth 44 in each exposed portion 45, and the gas supplied from each through hole 26 can be turned into plasma. The first electrode inside the substrate (and the third electrode if necessary) also needs to have a mesh pattern that faces the electrode 6A.

  As described above, when the planar pattern of the electrodes is comb-shaped, the pitch of the creeping discharge portions can be appropriately changed by changing the pitch of each comb-tooth portion 44. This is because creeping discharge occurs at the edge of each comb-tooth portion 44. Therefore, when the lifetime of the active species is short, the pitch of the comb-tooth portion 44 (or the width of the exposed portion 35) can be reduced to increase the number of creeping discharge locations.

  The planar shape of the through hole is substantially perfect circle in the above example, but is not limited to this, and is changed according to the material and form of the object to be processed and the type of active species. For example, the planar shape of the through hole may be an ellipse, a race track shape, a polygon such as a triangle, a quadrangle, or a hexagon, an elongated slit shape, or the like.

  The gas introduced from the through hole may be one type of gas or a plurality of types of gas may be supplied from the through hole depending on the intended reaction. In addition, when one kind of gas is supplied from the through hole, it may be a pure gas or a mixed gas. In addition, the gas supplied from the through hole can be converted into plasma by the action of creeping discharge, but a plurality of types of gas supplied from the through hole react with each other under the action of the creeping discharge to generate active species. You can also.

  The type of gas is not limited, but examples include rare gas (helium), argon, neon, etc.), nitrogen gas, oxygen gas, hydrogen, air (atmosphere), chlorine gas, ammonia gas, SF6, CF-based gas, and the like. Further, a liquid such as hydrogen peroxide, peracetic acid, ethanol, methanol, water or the like can be sprayed or evaporated to form a mist to be supplied from the through hole. Moreover, the above-mentioned gas and liquid can be used alone, or can be used as a mixture with other gases and liquids. As an example, oxygen can be activated using only oxygen gas to generate oxygen radicals and ozone gas, which can be used for sterilization applications, semiconductor wafers, removal of organic substances on glass, and surface modification.

  Moreover, the method of supplying gas or a mist-like liquid toward a 2nd electrode and a 3rd electrode is not limited, For example, it can supply with a gas cylinder and a blower. Moreover, gas (oxygen and hydrogen) generated by electrolysis can also be used. The gas pressure can usually be close to atmospheric pressure, and the supply flow rate of the original gas can be controlled by a mass flow meter or the like. Further, by providing a plurality of gas chambers and supplying different types of gases for each gas chamber, a plurality of types of activated gases can be supplied to the discharge space.

  FIG. 6 is a cross-sectional view schematically showing an example of a processing apparatus using the apparatus 30 of FIG. In this example, the roll 34 and the conveyance sheet 5 are used as conveyance means, the workpiece 21 is placed on the conveyance sheet 5, and the conveyance sheet 5 is moved to the right side in FIG. 6, for example. Plasma generating electrode devices 30 are respectively installed on the upper side and the lower side of the transport sheet, and the second electrode 6 </ b> A is opposed to the transport sheet 5. 35 is a container. In this example, the same type of gas is supplied from the upstream gas chambers 1a and 3a to the discharge spaces 1b and 3b, and a different type of gas is supplied from the downstream gas chambers 2a and 4a to the discharge space 2b. 4b. The gas chambers 1a and 3a and the gas chambers 2a and 4a are separated from each other by an airtight partition. 7 is a schematic diagram showing the roll 34, the conveying means 5, the workpiece 21 and the pair of plasma generating electrode devices 30 in FIG.

  In the above example, the conveying means is in the form of a sheet, but this specific form is not particularly limited, and may be a mesh or a net. The shape of the mesh is not particularly limited, and may be a polygon such as a perfect circle, an ellipse, a triangle, a quadrangle, or a hexagon. Further, the distance between the electrodes can be changed in accordance with the size of the object to be processed.

  After use, treatment of the activated gas itself is not necessary because the lifetime of the plasma active species is short. However, when the by-product gas is generated by the reaction between the activated gases, it is preferable to remove the active species by installing a catalyst on the downstream side of the plasma generating electrode device. Examples of such a catalyst include manganese-based catalysts and noble metal catalysts such as platinum. Depending on the type of gas, activated carbon can be used.

Example 1
In this example, a sheet 21 of polypropylene (hereinafter abbreviated as “PP”), which is a typical material for blister packs for pharmaceutical packaging, was used as an object to be processed. The sheet length was 300 mm and the width was 80 mm.

  As the plasma generating electrode device 30A, the one shown in FIG. 1B was used. In the apparatus 30A, 20 pieces of the upper stage and 20 pieces of the lower stage are arranged in a size of 100 mm in length, 100 mm in width, and 1 mm in thickness per substrate. A gap of 5 mm was formed between the upper substrate and the lower substrate. Of the substrate, a part made of SUS304 or a hard resin material was used for a portion in contact with the gas. Further, a mesh-like object was used as the conveying means 5 so that the back surface of the object 21 also reacts with the activation gas. Each substrate 40 has 50 through holes with a diameter of 2 mm per sheet.

  Since the second electrode (surface electrode) 6A and the third electrode 6B (surface electrode) are provided on both main surfaces of the substrate, discharge occurs in the gas chambers 1a, 2a, 3a, and 4a, respectively, and is activated by the plasma. Generate gas. And from the through-hole 26, activated gas and the gas which becomes the origin of activated gas eject. The inactive gas is activated by plasma in the discharge spaces 1b, 2b, 3b, 4b on the ejection side.

  Here, specifically, air is used as the original gas of the activation gas, is made dry air by the dehumidifying agent 18, and is sent to the gas chambers 1a and 3a by the blower 19 at a flow rate of 25 liters / minute. In addition to dry air, hydrogen peroxide solution 12 (31%) was vaporized by heating, and hydrogen peroxide gas was supplied at 0.2 g / min to the gas chambers 2a and 4a in the apparatus together with 25 L / min of dry air. . An experiment was also conducted on a case where only dry air was supplied to all the rooms.

Feedback control by the signal transmission type flow meter 15 and the control valve 16 was performed so that the supply rate of the dry air to the gas chamber was constant. Hydrogen peroxide gas was supplied to the gas chamber by measuring the evaporation residual with the load cell 11 and feedback controlling the amount of addition with the roller pump 13. 14 is an evaporator, and 17 is a heater.
Exhaust gas continuously generated with plasma treatment and exhaust gas remaining in the device after the supply of active gas (unreacted gas (hydrogen peroxide gas) and ozone gas generated by plasma, etc.) ) After being processed at 20, it is discharged out of the apparatus by the blower 19. In addition, the air curtain 22 was installed on both sides of the carry-in port and the carry-out port so that the activated gas and the ozone gas did not flow out from the inside of the apparatus.

The sterilization amount under each condition was measured by changing the conveyance speed and changing the plasma irradiation time to 30 seconds, 1 minute, 2 minutes, 5 minutes, and 10 minutes.
An SI thyristor pulse power supply (peak voltage: 1 to 20 kV, frequency: 0.1 to 5 kHz) was used as the plasma generator.

(Evaluation methods)
The sterilization effect was evaluated using a biological indicator (manufactured by Raven, USA, hereinafter abbreviated as BI) of Bacillus subtilis (Geobacillus stearothermophilus (ATCC # 7953)). Cellulose carrier with 1 × 10 ³ , 1 × 10 ⁴ , 1 × 10 ⁵ , 1 × 10 ⁶ bacteria attached is glassine paper (glassine paper: there are about 200 meshes per square mm, from the outside It is embedded in a structure that prevents the invasion of bacteria and the spread of spores inside and facilitates the inflow of airflow.

A predetermined number of test paper-type BIs were affixed onto a PP sheet, and after sterilization, the carrier was removed from the primary package (glassine paper) in an aseptic condition and cultured. Acumedia TSB (Tryptic
Soy Broth.) Using a culture solution in which a medium and a pH indicator (Bromocresol Purpule) are placed in a glass test tube, the sterilized test paper-type BI carrier is placed in the test tube while maintaining the sterility, and 58 to Culturing was performed at 60 ° C. for 7 days, and the presence or absence of sterilization was confirmed by a change in the color of the culture solution.

If sterilization has been achieved, there will be no change in the color of the culture solution. If sterilization is poor, the culture solution will change from purple to yellow due to the acid secreted by the bacteria. By using BI to which each number adhered, the amount of decrease in the number of bacteria was measured. The decrease in the number of bacteria is expressed in a logarithm. For example, when all the bacteria of 1 × 10 ⁶ cfu are killed, that is, when there is no change in the color of the culture solution after 7 days of culture, Log (1 × 10 ⁶ ) = This is expressed as 6. The results are shown in Table 1.

  As is clear from the results in Table 1, the PP sheet can be processed by continuous treatment in about 5 minutes if the sterilization level (Log 6), and in about 1 minute if the sterilization level (Log 3-5). Although only dry air is effective, the sterilization effect is further enhanced by adding hydrogen peroxide.

(Comparative Examples 1 and 2)
As Comparative Example 1, in the case of hydrogen peroxide gas alone without plasma irradiation, it took several tens of minutes to obtain the same result.
Similarly, in the case of the formaldehyde gas alone as Comparative Example 2, it takes several tens of minutes and is accompanied by a risk of residual gas.

(Example 2: Organic matter removal)
In this example, the object to be processed was a glass substrate and had a size of length 80 mm, width 80 mm, and thickness 1 mm. As the plasma generating electrode device 30A, the same one as in Example 1 was used. The substrate has 50 through holes with a diameter of 2 mm per sheet. The overall configuration of the apparatus is shown in FIG. Discharge also occurs on the gas chamber 3a side, and activated gas and ozone gas are generated by the plasma. From here, the gas which becomes the origin of activated gas, ozone gas, and activated gas ejects. The inactive gas on the gas chamber side is activated by plasma in the ejection side gas chamber 3b.
As the source gas of the activation gas, industrial oxygen 23 or dry air was supplied to the gas chamber 3a at a flow rate of 50 liters / minute. The supply of oxygen to the gas chamber was performed by feedback control using a signal transmission type flow meter 15 and a control valve 16 so that a constant amount was supplied. 18 is a dehumidifying agent and 27 is a regulator.

  The transport rate was fixed, and the amount of organic matter removed was measured with the plasma irradiation time as a fixed time. An SI thyristor pulse power supply (peak voltage: 1 to 20 kV, frequency: 0.1 to 5 kHz) was used as the plasma generator.

(Evaluation methods)
A predetermined amount of nonionic surfactant was added to ultrapure water (TOC concentration of 1 ppb or less), and a glass substrate (length 80 mm, width 80 mm, thickness 1 mm) was immersed in the solution for a certain period of time, and then dried products were tested. It was a piece. After cleaning with plasma, it was immersed in ultrapure water for a certain period of time, and the concentration of TOC dissolved in ultrapure water was measured to evaluate removal of organic substances. Furthermore, it compared with the thing which did not perform plasma processing.

  From the results of Table 2, the effect of cleaning with plasma was confirmed, and it was more effective by using oxygen as the original gas. Since plasma was generated on the electrode surface, the plasma was not directly applied to the glass substrate, and only organic substances could be effectively removed without causing damage.

(Example 3: Gas treatment)
Decomposition (deodorization) of the evaporation gas of the organic binder generated when firing ceramic products was performed. The evaporated organic binder gas generated from the drying furnace or the baking furnace is liquefied by the cooler 24, but a part thereof is discharged out of the furnace as the evaporated gas. Plasma is used to prevent the exhaust gas from sticking to the flue pipe and to decompose bad odors. Reference numeral 25 denotes a liquefied binder receiver.

  A surface discharge electrode device was used as the electrode. In this apparatus, gas is decomposed by plasma when passing through the through hole. Each electrode has 50 through holes with a diameter of 2 mm. The overall configuration of the apparatus is shown in FIG. There are surface electrodes 6A and 6B on both sides, discharge occurs in the gas chambers 1a and 3a, and the ejection side 1b, and the evaporated organic binder gas is decomposed by plasma.

  The non-liquefied evaporated organic binder gas and the evaporated organic binder gas that was not subjected to the liquefaction treatment were treated. The evaporated organic binder was sent to the apparatus with air at a flow rate of 25 L / min. Further, hydrogen peroxide evaporating gas was supplied at 0.2 g / min from the same side as the evaporating organic binder.

(Evaluation methods)
Evaluation was performed by measuring the concentrations of styrene and dibutyl phthalate contained in the evaporated organic binder gas. The concentration was measured by gas chromatography mass spectrometry.
Liquefaction treatment: Evaporated organic binder after passing through cooler Untreated: Organic binder not cooled

  From the results in Table 3, it was confirmed that the binder component could be decomposed. Moreover, it was more effective when hydrogen peroxide was added.

In addition, the vaporized organic binder gas to be decomposed and the gas that is the source of the active gas can be sent to separate rooms and mixed and reacted in an activated place.
For example, FIG. 11 shows an example in which air to which hydrogen peroxide gas is added is supplied to the gas chambers 1a and 3a and the evaporated organic binder is supplied to the gas chamber 1b.

  Further, the apparatus of FIG. 12 is the same as the apparatus of FIG. However, in the apparatus of FIG. 12, the air to which hydrogen peroxide gas is added is supplied to the gas chamber 1b side, and the evaporated organic binder is supplied to the outer gas chambers 1a and 3a side. When the concentration of the evaporated organic binder is low, the usage method as shown in FIG. 12 is also possible.

(A) is sectional drawing which shows typically the electrode apparatus 30 for plasma generation which concerns on one Embodiment of this invention, (b) is the electrode apparatus 30A for plasma generation which concerns on other embodiment of this invention. It is sectional drawing shown typically. (A) is sectional drawing which shows the components of the stage before manufacturing the electrode apparatus 30 for plasma generation of Fig.1 (a), (b) is 30 A of plasma generation electrode apparatuses of FIG.1 (b). It is sectional drawing which shows the components of the stage before manufacture. It is a top view of electrode apparatus 30B for plasma generation concerning other embodiments of the present invention. It is a perspective view which decomposes | disassembles and shows typically the electrode apparatus 30B for plasma generation of FIG. It is a perspective view which shows roughly 30 C of electrode apparatuses for plasma generation concerning other embodiment. It is sectional drawing which shows typically the whole structure of the plasma processing apparatus produced using the electrode apparatus 30 for plasma generation of Fig.1 (a). It is a perspective view which shows typically the roller 34, the conveyance sheet 5, the to-be-processed object 21, and the electrode apparatus 30 for plasma generation among the apparatuses of FIG. 1 is a schematic block diagram illustrating an overall configuration of a plasma processing apparatus used in Example 1. FIG. It is a typical block diagram which shows the whole structure of the plasma processing apparatus used in Example 2. FIG. It is a block diagram which shows the whole structure of the plasma processing apparatus used in Example 3. FIG. It is a block diagram which shows the whole structure of the plasma processing apparatus which can be used in Example 3. FIG. It is a block diagram which shows the whole structure of the plasma processing apparatus which can be used for the process of an evaporation organic binder in Example 3.

Explanation of symbols

6A Second electrode 6B Third electrode 7, 9 Dielectric layer 7a One main surface of substrate 40 8 Substrate 9a The other main surface of substrate 40 26 Through-hole 30, 30A, 30B, 30C Plasma generating electrode device 31 40 Substrate 32 Mesh 40 Substrate 43 Common electrode 44 Comb portion 45 Exposed portion A, B Gas flow D Creeping discharge

Claims (8)

An electrode device for generating plasma,
A dielectric substrate; a first electrode embedded in the substrate; and a second electrode provided on one main surface of the substrate, wherein a through hole is formed in the substrate. And a plasma generating electrode device for generating plasma by creeping discharge generated along the substrate from the second electrode. The plasma generating electrode device according to claim 1, wherein the first electrode is embedded in the substrate so as not to be exposed in the through hole. 3. The plasma generating electrode device according to claim 1, wherein the second electrode has a net shape or a comb shape. The plasma processing apparatus according to claim 1, further comprising a third electrode on the other main surface of the substrate, wherein plasma is generated by creeping discharge generated along the substrate from the third electrode. The electrode device for plasma generation as described. 5. An exposed region in which the main surface of the substrate is exposed between the second electrode and the through hole, and creeping discharge is generated along the exposed region. The electrode apparatus for plasma generation as described in any one of Claims. The plasma generating electrode device according to claim 1, wherein the plasma generating gas is supplied through the through hole. The plasma generating electrode device according to any one of claims 1 to 6, wherein the object to be processed is plasma-treated while being conveyed by a conveying means. The electrode device for plasma generation according to any one of claims 1 to 7, wherein the plasma is generated for sterilization or sterilization of an article.

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