WO2023095420A1 - Plasma generator - Google Patents
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- WO2023095420A1 WO2023095420A1 PCT/JP2022/034027 JP2022034027W WO2023095420A1 WO 2023095420 A1 WO2023095420 A1 WO 2023095420A1 JP 2022034027 W JP2022034027 W JP 2022034027W WO 2023095420 A1 WO2023095420 A1 WO 2023095420A1
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/30—Plasma torches using applied electromagnetic fields, e.g. high frequency or microwave energy
Definitions
- the present invention relates to a plasma generator that generates plasma.
- Atmospheric pressure plasma does not require a vacuum vessel or exhaust equipment, and has the advantage that the particle density of active species in the plasma is higher than in a low-pressure environment, enabling high-speed processing.
- discharge plasma is generated by ionizing neutral particles by giving energy to electrons by the electric field of the microwaves radiated into space.
- Microwave discharge does not require electrodes or dielectrics (insulators) in contact with the plasma, which are required for dielectric barrier discharge, which is well known for atmospheric pressure plasma generation, and can suppress the contamination of plasma with impurities. .
- the microwave plasma generator has a track record of plasma generation with many gas species such as argon, nitrogen, hydrogen, and air, and has the advantage of being able to handle various plasma irradiation conditions.
- Patent Document 1 describes a plasma processing apparatus that can point-pointly irradiate plasma.
- an antenna (radiator) for inputting and radiating a high-frequency signal and an insulator are provided in a torch-shaped housing, and the inner diameter of one end is larger than the inner diameter of the part where plasma is generated.
- the insulator is formed to have a small diameter, so that a sufficient amount of plasma discharge gas can be positioned around the antenna by securing a sufficient space around the antenna. Plasma can be applied pointwise to an extremely narrow area on the top.”
- Patent Literature 1 describes a plasma processing apparatus that irradiates plasma of various diameters pointwise by using an insulating tube whose inner diameter at one end is smaller than the inner diameter of the portion where plasma is generated. It is
- a gas supply source that supplies gas to the inside of the plasma generation part, a high frequency power supply that supplies high frequency power to the inside of the plasma generation part, and a plasma generation part disposed in the plasma generation part.
- An insulator is disposed between the discharge antenna in the plasma generating part and a metal housing surrounding it, and the gas flow path inside the insulator is directed to the gas upstream.
- a plasma generator comprising a gas retention portion, a tapered portion, a throat portion, and a diverging portion in order from the side, wherein the tip of the discharge antenna is disposed between the inlet of the tapered portion and the throat portion. ”.
- FIG. 1 is a front cross-sectional view showing a schematic configuration of a plasma generation apparatus for generating plasma according to Embodiment 1 of the present invention
- 7 is a graph showing the frequency characteristics of the S-parameters of the transmission path with respect to the antenna length;
- the plasma generator of the present invention is intended to be used for improving hydrophilicity by modifying the surface of culture substrates such as culture plates made of organic materials used for cell culture. .
- the culture substrate which is an organic material
- active species that are generated in plasma and readily cause chemical reactions are important for surface modification of culture substrates.
- the generation efficiency of active species can be increased by increasing the interaction between the high electric field at the tip of the antenna and the gas.
- the lifetime of active species is as short as 1 ⁇ s to 1 ms, and the percentage of active species in the plasma decreases sharply as the distance between the plasma generation section and the irradiation section increases.
- FIG. 1 is a front cross-sectional view showing a configuration example of a plasma generation apparatus 100 according to an embodiment of the present invention.
- the plasma generation apparatus 100 includes a plasma generation unit 1, a gas supply source 60 that supplies a working gas to the inside of the plasma generation unit 1, and electric power for generating plasma inside the plasma generation unit 1.
- a high frequency power supply 50 is provided to supply power.
- the working gas is supplied from the gas supply source 60 to the inside of the plasma generation unit 1, and the high frequency power oscillated from the high frequency power supply 50 is supplied to the plasma excitation unit 90 to generate plasma.
- Plasma is delivered through the plasma delivery unit 91 to irradiate the object to be processed, thereby performing plasma processing.
- the plasma generator 1 includes an outer conductor 3, a coaxial cable 51, a coaxial connector 52, a supply conductor 10, an antenna 11 as a radiation conductor, an insulating cylinder 5, and a holding conductor 70, as shown in FIG.
- the outer conductor 3 is a conductive cylindrical body with an opening on at least one side, and the opening is formed with a plasma sending part 91 constituted by the insulating cylinder 5 .
- the insulating cylinder 5 is composed of a dielectric such as a quartz tube or an alumina tube.
- the insulating tube 5 is arranged coaxially with the antenna 11 with a holding conductor 70 having O-rings 40a and 40b.
- the O-rings 40 a and 40 b are in close contact with the outer peripheral surface of the insulating cylinder 5 while being mounted in the recesses 70 and 71 provided in the holding conductor 70 .
- the O-rings 40a, 40b are dielectric with high heat resistance.
- One end of the antenna 11 is fixed to the center of the bottom surface 301 inside the cylinder of the outer conductor 3, and the other end protrudes inside the insulating cylinder 5 held by the holding conductor 70 mounted inside the outer conductor 3. are arranged to In this state, the central axis of the insulating tube 5 and the central axis of the antenna 11 are aligned.
- the O-ring 40 a in a state of being mounted in a recess 71 formed in the holding conductor 70 , is positioned below the end 5 a of the insulating tube 5 near the bottom surface 301 of the cylindrical body of the outer conductor 3 to insulate the antenna 11 . It is arranged at the same position as the tip portion 11a of the antenna 11 projecting into the tube 5 or above it (on the side near the bottom surface 301 of the tube of the outer conductor 3).
- a high-frequency power supply 50 generates a high-frequency signal in a quasi-microwave band (1 GHz to 3 GHz) or a microwave band (3 GHz to 30 GHz) with a predetermined power, and is connected to an external conductor by a coaxial connector 52 via a coaxial cable 51. to output high-frequency power to the plasma generator 1 .
- the microwave energy is concentrated to the antenna 11 installed adjacent and parallel to the supply conductor 10. configured to be sent.
- a magnetic field is generated concentrically around the axis through which the current flows.
- an antenna with a length equivalent to 1/4 (30.6 mm) of the wavelength 11 a microwave electric field is generated at the tip 11a of the antenna 11, and plasma is generated.
- a matching box may be provided between the high frequency power supply 50 and the plasma generating section 1 in order to increase the efficiency of supplying the high frequency signal for generating plasma from the high frequency power supply 50 .
- the working gas for plasma discharge is supplied from the gas supply unit 60 through the gas pipe 61 and the flow rate is adjusted by the mass flow controller 62. Introduced in 92.
- the plasma 99 generated in the plasma excitation part 90 inside the insulating cylinder 5 is supplied from the gas supply source 60 and is emitted from the plasma sending part 91 along the flow controlled by the flow path provided inside the insulating cylinder 5. It flows out of the generator 1 .
- the inside of the insulating cylinder 5 has a nozzle shape that tapers and diverges from the end portion 5a toward the plasma delivery portion 91 downstream. Downstream from the end 5a is a gas retention section 200 followed by a tapered section 201, a throat section 202 and a diverging section 203.
- FIG. 1 A gas retention section 200 followed by a tapered section 201, a throat section 202 and a diverging section 203.
- the tip portion 11 a of the antenna 11 is arranged between the entrance of the tapered portion 201 and the entrance of the throat portion 202 .
- the flow speeds up toward the tip portion 11a of the antenna 11 where plasma is generated, and the flow concentrates to increase the flow rate of the gas that interacts with the high electric field portion near the tip portion 11a of the antenna 11.
- the efficiency of plasma generation can be increased.
- the temperature of the plasma can also be lowered by arranging an insulator having a higher thermal conductivity than the gas near the plasma generating section to improve the heat radiation efficiency.
- the shape of the tapered and divergent nozzle inside the insulating cylinder 5 is determined so that the plasma irradiation speed is low.
- the plasma irradiation at a low speed is assumed to be a speed at which scattering or movement of the culture substrate, which is an object, is not a problem due to plasma irradiation even if it is not held down by a special jig. Since the appropriate speed at this time varies depending on the method of surface treatment of the object, it is preferable to set it appropriately. s or less is desirable.
- the flow area of the end portion 5a of the insulating cylinder 5 is S2
- the flow area of the inlet of the nozzle throat 202 is S3
- the flow area of the plasma delivery portion 91 at the outlet of the divergent portion is S4
- the relationship between the flow passage areas of the respective portions is set to S2>S4>S3>S1 in order to realize low-speed plasma irradiation.
- the flow rate is 2 L/min
- the inner diameter of the gas introduction pipe 63 is 2 mm
- the flow area is 3.14 mm 2
- the flow velocity of the working gas is 10.6 m/s.
- the flow velocity is 0.4 m/s.
- the flow velocity is 5.2 m/s, and the flow velocity is 0.1 m/s if the flow area of the outlet of the divergent portion is multiplied by 150.
- FIG. 2 shows, as an example, the frequency characteristics of the S parameter for evaluating the reflected power of the transmission line for microwaves of 2.45 GHz.
- the plasma temperature is lowered by increasing the gas flow rate in the high electric field portion at the tip of the antenna, and the high electric field portion at the tip of the antenna and the gas Therefore, it is possible to provide a plasma generation apparatus capable of realizing low-speed plasma irradiation by flowing gas from the throat portion to the diverging portion.
- This structure is similar to the structure of Patent Document 1 in that the inside of the insulating cylinder 5 has a tapered and diverging nozzle shape, but it differs greatly in the following two points.
- the first point is that the tip portion 11a of the antenna 11 is arranged between the entrance of the tapered portion 201 and the entrance of the throat portion 202 (in other words, inside the tapered portion 201).
- a tip portion 11 a of the antenna 11 is arranged in the gas retention portion 200 .
- the second point is the shape of the antenna 11.
- the gas flow passes between the two antennas arranged around the inside of the insulating cylinder 5. is to allow the gas stream to pass through.
- 1 plasma generator
- 3 external conductor
- 5 insulating cylinder
- 5a insulating cylinder end
- 10 supply conductor
- 11 antenna
- 11a antenna tip
- 40a, 40b O-ring
- 50 high frequency power supply
- 51 coaxial cable
- 52 coaxial connector
- 60 gas supply source
- 61 gas pipe
- 62 mass flow controller
- 63 gas introduction pipe
- 70 holding conductor
- 90 plasma excitation section
- 91 plasma delivery section
- 92 gas rectifying section
- 99 plasma
- 200 gas retention section
- 201 tapered section
- 202 throat section
- 203 divergent section
Abstract
Provided is a plasma generator with which: reduction in plasma temperature and improvement of active species generation efficiency can be achieved; and an object can be irradiated with plasma while an increase in the speed of plasma generated in a plasma generation part is suppressed. This plasma generator comprises: a gas supply source for supplying gas into a plasma generation part; a high frequency power source for supplying high frequency power into the plasma generation part; and a discharge antenna that is provided inside the plasma generation part and in which plasma is generated. The plasma generator is characterized in that: an insulating material is disposed between the discharge antenna and a metal casing that surrounds the antenna in the plasma generation part; a gas flow passage in the insulating material is formed from a gas retention part, a taper part, a throat part, and a divergent part in this order from the gas upstream side; and the tip of the discharge antenna is located between the inlet of the taper part and the throat part.
Description
本発明は、プラズマを生成するプラズマ生成装置に関する。
The present invention relates to a plasma generator that generates plasma.
大気圧プラズマは、真空容器や排気設備が不要であり、減圧環境に比べてプラズマ内の活性種の粒子密度が高く、高速処理が可能であるという利点がある。プラズマの生成法にマイクロ波を使った場合、放電プラズマは空間に放射されるマイクロ波の電界により電子にエネルギーを与え、中性粒子を電離することにより生成される。
Atmospheric pressure plasma does not require a vacuum vessel or exhaust equipment, and has the advantage that the particle density of active species in the plasma is higher than in a low-pressure environment, enabling high-speed processing. When microwaves are used to generate plasma, discharge plasma is generated by ionizing neutral particles by giving energy to electrons by the electric field of the microwaves radiated into space.
マイクロ波放電では、大気圧プラズマ生成でよく知られた誘電体バリア放電に必要となる電極やプラズマに接する誘電体（絶縁体）が不要であり、プラズマへの不純物の混入を抑制することができる。
Microwave discharge does not require electrodes or dielectrics (insulators) in contact with the plasma, which are required for dielectric barrier discharge, which is well known for atmospheric pressure plasma generation, and can suppress the contamination of plasma with impurities. .
また、マイクロ波放電によって生成されたプラズマをガス流によって放電部から移送することで、プラズマ生成部と照射部を分離したリモート処理を行うことが可能であり、原理的には対象物の寸法やどのような形状の表面でも処理することができる。リモート処理に用いられる方式の一つに低周波大気圧プラズマジェットがあるが、低周波大気圧プラズマジェットの場合、放電ガスがヘリウムに限定される。
In addition, by transferring the plasma generated by the microwave discharge from the discharge part by gas flow, it is possible to perform remote processing with the plasma generation part and the irradiation part separated. Surfaces of any shape can be treated. One method used for remote processing is a low-frequency atmospheric pressure plasma jet, but in the case of the low-frequency atmospheric pressure plasma jet, the discharge gas is limited to helium.
一方、マイクロ波プラズマ発生装置では、アルゴン、窒素、水素、空気など、多くのガス種によるプラズマ生成実績があり、様々なプラズマ照射条件に対応できる利点がある。
On the other hand, the microwave plasma generator has a track record of plasma generation with many gas species such as argon, nitrogen, hydrogen, and air, and has the advantage of being able to handle various plasma irradiation conditions.
プラズマを点的に照射し得るプラズ処理装置が特許文献１に記載されている。この特許文献１には、「トーチ型の筐体内に、高周波信号を入力して放射するアンテナ（放射器）と絶縁体を備え、プラズマが発生する部位の内径よりも一端部の内径の方が小径となるように絶縁体を形成する。これにより、アンテナの周囲に十分なスペースを確保して十分な量のプラズマ放電用ガスをアンテナの周囲に位置させることができ、さらには、処理対象体上の極く狭い領域に対してプラズマを点的に照射することができる。」と記載されている。
Patent Document 1 describes a plasma processing apparatus that can point-pointly irradiate plasma. In this patent document 1, "an antenna (radiator) for inputting and radiating a high-frequency signal and an insulator are provided in a torch-shaped housing, and the inner diameter of one end is larger than the inner diameter of the part where plasma is generated. The insulator is formed to have a small diameter, so that a sufficient amount of plasma discharge gas can be positioned around the antenna by securing a sufficient space around the antenna. Plasma can be applied pointwise to an extremely narrow area on the top."
特許文献１には、プラズマが発生する部位の内径よりも一端部の内径の方が小径となるような絶縁管を使用することで、各種径のプラズマを点的に照射するプラズマ処理装置が記載されている。
Patent Literature 1 describes a plasma processing apparatus that irradiates plasma of various diameters pointwise by using an insulating tube whose inner diameter at one end is smaller than the inner diameter of the portion where plasma is generated. It is
この場合、プラズマが発生する部位の内径が広いためアンテナ先端の高電界部での流速が遅く相互作用するガス流量が少ないため、生成されるプラズマのガス温度が上昇し、さらには活性種の生成効率が抑制される。また、高速の大気圧プラズマが、点的に対象物にあたると、対象物が飛散、移動してしまうという問題があった。
In this case, since the inner diameter of the part where the plasma is generated is wide, the flow velocity in the high electric field part at the tip of the antenna is low and the flow rate of interacting gas is small. Efficiency is suppressed. Moreover, when the high-speed atmospheric pressure plasma hits the object pointwise, there is a problem that the object scatters and moves.
以上のことから本発明の目的は、プラズマ温度の低温化と活性種の生成効率の向上を実現することができるプラズマ生成装置を提供することにある。さらには、プラズマ生成部で生成したプラズマの高速化を抑制して、対象物にプラズマを照射できる、プラズマ生成装置を提供することにある。
In view of the above, an object of the present invention is to provide a plasma generation apparatus capable of lowering the plasma temperature and improving the generation efficiency of active species. Another object of the present invention is to provide a plasma generation apparatus capable of irradiating an object with plasma while suppressing the acceleration of the plasma generated in the plasma generation section.
以上のことから本発明においては、「プラズマ生成部の内部にガスを供給するガス供給源と、プラズマ生成部の内部に高周波電力を供給する高周波電源と、プラズマ生成部内に配置されてプラズマを発生する放電用アンテナを備えたプラズマ発生装置であって、プラズマ生成部内の放電用アンテナとそれを囲む金属筐体との間に絶縁物を配置し、絶縁物の内部のガス流路が、ガス上流側から順にガス滞留部、先細部、スロート部、末広部で構成されており、放電用アンテナの先端が先細部の入口とスロート部との間に配置されていることを特徴とするプラズマ発生装置」としたものである。
From the above, in the present invention, "a gas supply source that supplies gas to the inside of the plasma generation part, a high frequency power supply that supplies high frequency power to the inside of the plasma generation part, and a plasma generation part disposed in the plasma generation part. An insulator is disposed between the discharge antenna in the plasma generating part and a metal housing surrounding it, and the gas flow path inside the insulator is directed to the gas upstream. A plasma generator comprising a gas retention portion, a tapered portion, a throat portion, and a diverging portion in order from the side, wherein the tip of the discharge antenna is disposed between the inlet of the tapered portion and the throat portion. ”.
本発明によれば、プラズマ温度の低温化と活性種の生成効率の向上を実現することができ、さらには、プラズマ生成部で生成したプラズマの高速化を抑制して、対象物にプラズマを照射できる。
According to the present invention, it is possible to lower the plasma temperature and improve the generation efficiency of active species. can.
上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。
Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.
以下、本発明の実施例を図面に基づいて詳細に説明する。
Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
ただし、本発明は以下に示す実施例の記載内容に限定して解釈されるものではない。本発明の思想ないし趣旨から逸脱しない範囲で、その具体的構成を変更し得ることは当業者であれば容易に理解される。
However, the present invention should not be construed as being limited to the contents of the examples shown below. Those skilled in the art will easily understand that the specific configuration can be changed without departing from the idea or gist of the present invention.
本発明のプラズマ生成装置は、細胞培養に使われる有機材料で形成された培養皿などの培養基材を対象物として、その表面改質による親水性の向上などに使用することを想定している。
The plasma generator of the present invention is intended to be used for improving hydrophilicity by modifying the surface of culture substrates such as culture plates made of organic materials used for cell culture. .
この場合、プラズマ照射により、有機材料である培養基材の変形・変質がないためには、プラズマの低温化が必要である。さらに、培養基材の表面改質には、プラズマ中に生成され、化学反応を起こしやすい活性種が重要である。活性種の生成は、アンテナ先端の高電界部とガスとの相互作用を増やすことで生成効率を高めることができる。活性種の寿命は1μsから1msと短く、プラズマ生成部と照射部との距離が長くなるとプラズマ中の活性種の割合は急激に少なくなる。
In this case, it is necessary to lower the plasma temperature so that the culture substrate, which is an organic material, is not deformed or degraded by plasma irradiation. Furthermore, active species that are generated in plasma and readily cause chemical reactions are important for surface modification of culture substrates. The generation efficiency of active species can be increased by increasing the interaction between the high electric field at the tip of the antenna and the gas. The lifetime of active species is as short as 1 μs to 1 ms, and the percentage of active species in the plasma decreases sharply as the distance between the plasma generation section and the irradiation section increases.
プラズマの対象物までの到達時間を短くするために高速流とすると、重量の軽い対象物の場合には、飛散や移動が問題になる場合がある。
If a high-speed flow is used to shorten the arrival time of the plasma to the target, scattering and movement may become a problem for light-weight targets.
実施例では、上記した用途に好適なプラズマ生成装置について説明する。図１は、本発明の実施例に係るプラズマ生成装置１００の構成例を示す正面の断面図である。
In the embodiment, a plasma generator suitable for the above applications will be described. FIG. 1 is a front cross-sectional view showing a configuration example of a plasma generation apparatus 100 according to an embodiment of the present invention.
本実施例に係るプラズマ生成装置１００は、プラズマ生成部１と、プラズマ生成部１の内部に動作ガスを供給するガス供給源６０と、プラズマ生成部１の内部にプラズマを発生させるための電力を供給する高周波電源５０を備えている。
The plasma generation apparatus 100 according to the present embodiment includes a plasma generation unit 1, a gas supply source 60 that supplies a working gas to the inside of the plasma generation unit 1, and electric power for generating plasma inside the plasma generation unit 1. A high frequency power supply 50 is provided to supply power.
このプラズマ生成装置１００では、プラズマ生成部１の内部にガス供給源６０から動作ガスを供給し、高周波電源５０から発振された高周波電力をプラズマ励起部９０に供給してプラズマを生成し、生成したプラズマを、プラズマ送出部９１を通して送出して被処理物に照射しプラズマによる処理を行う。
In this plasma generation apparatus 100, the working gas is supplied from the gas supply source 60 to the inside of the plasma generation unit 1, and the high frequency power oscillated from the high frequency power supply 50 is supplied to the plasma excitation unit 90 to generate plasma. Plasma is delivered through the plasma delivery unit 91 to irradiate the object to be processed, thereby performing plasma processing.
プラズマ生成部１は、図１に示すように、外部導体３、同軸ケーブル５１、同軸コネクタ５２、供給導体１０、放射導体としてのアンテナ１１、絶縁筒５、保持導体７０を備えている。
The plasma generator 1 includes an outer conductor 3, a coaxial cable 51, a coaxial connector 52, a supply conductor 10, an antenna 11 as a radiation conductor, an insulating cylinder 5, and a holding conductor 70, as shown in FIG.
このうち外部導体３は、少なくとも片側が開口した導電性の筒体になっており、開口部に絶縁筒５によって構成された、プラズマ送出部９１が形成されている。
Among them, the outer conductor 3 is a conductive cylindrical body with an opening on at least one side, and the opening is formed with a plasma sending part 91 constituted by the insulating cylinder 5 .
絶縁筒５は、石英管やアルミナ管などの誘電体で構成されている。絶縁筒５は、Ｏリング４０ａ、４０ｂを設置した保持導体７０でアンテナ１１と同軸に配置される。Ｏリング４０ａ、４０ｂは、保持導体７０に設けた凹部７０．７１に装着された状態で絶縁筒５の外周面に密着している。例えば、Ｏリング４０ａ、４０ｂは、耐熱性の高い、誘電体である。
The insulating cylinder 5 is composed of a dielectric such as a quartz tube or an alumina tube. The insulating tube 5 is arranged coaxially with the antenna 11 with a holding conductor 70 having O- rings 40a and 40b. The O- rings 40 a and 40 b are in close contact with the outer peripheral surface of the insulating cylinder 5 while being mounted in the recesses 70 and 71 provided in the holding conductor 70 . For example, the O- rings 40a, 40b are dielectric with high heat resistance.
アンテナ１１の一端は、外部導体３の筒体の内部の底面３０１の中心に固定され、他端は外部導体３の内部に装着された保持導体７０に保持されている絶縁筒５の内部に突出するように配置されている。この状態で、絶縁筒５の中心軸とアンテナ１１の中心軸が一致する構成となっている。
One end of the antenna 11 is fixed to the center of the bottom surface 301 inside the cylinder of the outer conductor 3, and the other end protrudes inside the insulating cylinder 5 held by the holding conductor 70 mounted inside the outer conductor 3. are arranged to In this state, the central axis of the insulating tube 5 and the central axis of the antenna 11 are aligned.
Ｏリング４０ａは、保持導体７０に形成された凹部７１に装着された状態で、外部導体３の筒体の底面３０１に近い側の絶縁筒５の端部５ａより下側で、アンテナ１１の絶縁筒５内に突出したアンテナ１１の先端部１１ａの位置と同じか、それよりも上側（外部導体３の筒体の底面３０１に近い側）に配置される。
The O-ring 40 a , in a state of being mounted in a recess 71 formed in the holding conductor 70 , is positioned below the end 5 a of the insulating tube 5 near the bottom surface 301 of the cylindrical body of the outer conductor 3 to insulate the antenna 11 . It is arranged at the same position as the tip portion 11a of the antenna 11 projecting into the tube 5 or above it (on the side near the bottom surface 301 of the tube of the outer conductor 3).
高周波電源５０は、準マイクロ波帯（１ＧＨｚ～３ＧＨｚ）またはマイクロ波帯（３ＧＨｚ～３０ＧＨｚ）の高周波信号を所定の電力で生成すると共に、同軸ケーブル５１を介して同軸コネクタ５２で外部導体を接続されてプラズマ生成部１に高周波電力を出力する。同軸ケーブル５１の終端を供給導体１０と接続して逆Ｌ字で外部導体３の底面３０１と短絡させることで、供給導体１０と隣接して平行に設置したアンテナ１１へマイクロ波エネルギーを集中的に送ることができるように構成されている。
A high-frequency power supply 50 generates a high-frequency signal in a quasi-microwave band (1 GHz to 3 GHz) or a microwave band (3 GHz to 30 GHz) with a predetermined power, and is connected to an external conductor by a coaxial connector 52 via a coaxial cable 51. to output high-frequency power to the plasma generator 1 . By connecting the terminal end of the coaxial cable 51 to the supply conductor 10 and short-circuiting it with the bottom surface 301 of the outer conductor 3 in an inverted L shape, the microwave energy is concentrated to the antenna 11 installed adjacent and parallel to the supply conductor 10. configured to be sent.
このような構成において、電流が流れる軸を中心に同心円状に磁場が発生するので、一例として、２．４５ＧＨｚマイクロ波の場合、その波長の１／４（３０．６ｍｍ）に値する長さのアンテナ１１との共振が起き、アンテナ１１の先端部１１ａでマイクロ波電界が作られ、プラズマが発生する。このとき、高周波電源５０からプラズマを生成する高周波信号の供給効率を高めるため、高周波電源５０とプラズマ生成部１との間に整合器を配設することもできる。
In such a configuration, a magnetic field is generated concentrically around the axis through which the current flows. As an example, in the case of a 2.45 GHz microwave, an antenna with a length equivalent to 1/4 (30.6 mm) of the wavelength 11, a microwave electric field is generated at the tip 11a of the antenna 11, and plasma is generated. At this time, a matching box may be provided between the high frequency power supply 50 and the plasma generating section 1 in order to increase the efficiency of supplying the high frequency signal for generating plasma from the high frequency power supply 50 .
プラズマ放電用の動作ガスは、ガス供給部６０からガス配管６１を通してマスフローコントローラ６２で流量が調整されたうえで、外部導体３に設けたガス導入管６３を介して外部導体３内のガス整流部９２に導入される。絶縁筒５の内部のプラズマ励起部９０で発生したプラズマ９９は、ガス供給源６０から供給され、絶縁筒５の内部に設けた流路で制御された流れに沿って、プラズマ送出部９１からプラズマ生成部１の外部に流れ出る。
The working gas for plasma discharge is supplied from the gas supply unit 60 through the gas pipe 61 and the flow rate is adjusted by the mass flow controller 62. Introduced in 92. The plasma 99 generated in the plasma excitation part 90 inside the insulating cylinder 5 is supplied from the gas supply source 60 and is emitted from the plasma sending part 91 along the flow controlled by the flow path provided inside the insulating cylinder 5. It flows out of the generator 1 .
絶縁筒５の内部は、端部５ａから下流のプラズマ送出部９１に向かって先細末広ノズル形状となっている。端部５ａから下流にガス滞留部２００があり、続いて先細部２０１と、スロート部２０２と、末広部２０３が設けられている。
The inside of the insulating cylinder 5 has a nozzle shape that tapers and diverges from the end portion 5a toward the plasma delivery portion 91 downstream. Downstream from the end 5a is a gas retention section 200 followed by a tapered section 201, a throat section 202 and a diverging section 203. FIG.
このとき、先細部２０１の入り口とスロート部２０２の入り口の間にアンテナ１１の先端部１１ａが配置されている。これにより、プラズマが生成されるアンテナ１１の先端部１１ａに向かって流れが早くなるとともに、流れが集中して、アンテナ１１の先端部１１ａ近傍の高電界部と相互作用するガス流量が増加することで、プラズマの生成効率を高めることができる。さらに、高電界部で発生したプラズマの滞在時間が短くなるため、プラズマが高温になることを抑制することができる。また、一般に、ガスよりも熱伝導率の高い絶縁物をプラズマ生成部の近傍に配置して、放熱効率を高めることでもプラズマの低温化をはかることができる。
At this time, the tip portion 11 a of the antenna 11 is arranged between the entrance of the tapered portion 201 and the entrance of the throat portion 202 . As a result, the flow speeds up toward the tip portion 11a of the antenna 11 where plasma is generated, and the flow concentrates to increase the flow rate of the gas that interacts with the high electric field portion near the tip portion 11a of the antenna 11. , the efficiency of plasma generation can be increased. Furthermore, since the residence time of the plasma generated in the high electric field portion is shortened, it is possible to suppress the plasma from becoming hot. In general, the temperature of the plasma can also be lowered by arranging an insulator having a higher thermal conductivity than the gas near the plasma generating section to improve the heat radiation efficiency.
絶縁筒５の内部の先細末広ノズル形状は、プラズマ照射が低速になるように決める。ここで低速でのプラズマ照射とは、プラズマの照射により対象物である培養基材が、特別な治具で抑えなくても飛散や移動が問題にならない速度を想定している。このときの適切な速度は、対象物の表面処理の仕方に応じても変わるため、適宜に設定されるのがよいが、具体的な数値としては、対象物に届く時の流速が数ｍ／ｓ以下であることが望ましい。
The shape of the tapered and divergent nozzle inside the insulating cylinder 5 is determined so that the plasma irradiation speed is low. Here, the plasma irradiation at a low speed is assumed to be a speed at which scattering or movement of the culture substrate, which is an object, is not a problem due to plasma irradiation even if it is not held down by a special jig. Since the appropriate speed at this time varies depending on the method of surface treatment of the object, it is preferable to set it appropriately. s or less is desirable.
照射プラズマの流速が数ｍ／ｓ以下になるように、絶縁筒５の内部の先細末広ノズル形状の各部の流路面積は決められる。マスフローコントローラ６２で調整された動作ガスの流量をＱＬ／ｍｉｎ、ガス導入管６３の流路面積をＳ１ｍ３とすると、ガスの流速ｖ１は、ｖ１＝Ｑ／（６０×Ｓ１）ｍ／ｓとなる。各流路での流量が保存されるとして、絶縁筒５の端部５ａの流路面積をＳ２、ノズルスロート２０２の入口の流路面積をＳ３、末広部出口のプラズマ送出部９１の流路面積をＳ４とすると、低速でのプラズマ照射を実現するため、各部の流路面積の関係をＳ２＞Ｓ４＞Ｓ３＞Ｓ１とする。例えば、流量２Ｌ／ｍｉｎで、ガス導入管６３の内径が２ｍｍで流路面積が３．１４ｍｍ２の場合、動作ガスの流速は１０．６ｍ／ｓとなる。ガス導入管６３の流路面積に対して、絶縁筒５の端部５ａの流路面積を２５倍にすると流速は０．４ｍ／ｓ、ノズルスロート２０２の入口の流路面積を２倍とすると流速は５．２ｍ／ｓ、末広部出口の流路面積を１５０倍とすれば流速は０．１ｍ／ｓとなる。
The flow area of each portion of the tapered nozzle inside the insulating cylinder 5 is determined so that the flow velocity of the irradiated plasma is several m/s or less. Assuming that the flow rate of the working gas adjusted by the mass flow controller 62 is QL/min and the flow area of the gas introduction pipe 63 is S1m3 , the flow velocity v1 of the gas is v1=Q/(60*S1)m/s. . Assuming that the flow rate in each flow path is preserved, the flow area of the end portion 5a of the insulating cylinder 5 is S2, the flow area of the inlet of the nozzle throat 202 is S3, and the flow area of the plasma delivery portion 91 at the outlet of the divergent portion is is S4, the relationship between the flow passage areas of the respective portions is set to S2>S4>S3>S1 in order to realize low-speed plasma irradiation. For example, when the flow rate is 2 L/min, the inner diameter of the gas introduction pipe 63 is 2 mm, and the flow area is 3.14 mm 2 , the flow velocity of the working gas is 10.6 m/s. When the flow area of the end portion 5a of the insulating cylinder 5 is 25 times the flow area of the gas introduction pipe 63, the flow velocity is 0.4 m/s. The flow velocity is 5.2 m/s, and the flow velocity is 0.1 m/s if the flow area of the outlet of the divergent portion is multiplied by 150.
図２は、一例として、２．４５ＧＨｚのマイクロ波に対する伝送路の反射電力を評価するＳパラメータの周波数特性である。マイクロ波の伝送路の特性を表すＳパラメータ（Ｓ１１＝反射波／入射波）の吸収ピークの周波数が２．４５ ＧＨｚに近く、また、吸収が大きいほど供給した電力がアンテナ先端部で消費されていることを表すため、吸収ピークは負に大きいほど伝送路インピーダンス整合が良いと言える。吸収ピークが２．４５ＧＨｚからずれてしまうような場合には、プラズマの点火の不具合が発生し、あるいは伝送路の反射電力が大きくなってプラズマの生成効率が低下してしまう。
FIG. 2 shows, as an example, the frequency characteristics of the S parameter for evaluating the reflected power of the transmission line for microwaves of 2.45 GHz. The frequency of the absorption peak of the S-parameter (S11 = reflected wave/incident wave), which represents the characteristics of the microwave transmission path, is close to 2.45 GHz, and the greater the absorption, the more power is consumed at the tip of the antenna. Therefore, it can be said that the larger the negative absorption peak is, the better the transmission line impedance matching is. If the absorption peak deviates from 2.45 GHz, plasma ignition failure occurs, or the reflected power in the transmission line increases, resulting in a decrease in plasma generation efficiency.
絶縁筒５の端部５ａから下流にガス滞留部２００を設けることで、ガスの流れを良くするのと合わせて、アンテナ１１と絶縁物５との距離を確保することができるので、伝送路の反射電力を抑えるための伝送路インピーダンス整合の調整が容易になる。
By providing the gas retention portion 200 downstream from the end portion 5a of the insulating tube 5, it is possible to improve the flow of gas and secure the distance between the antenna 11 and the insulator 5, thereby improving the transmission path. Adjustment of transmission line impedance matching for suppressing reflected power is facilitated.
上記した本発明の実施例によれば、このような構成にすることで、アンテナ先端の高電界部のガス流量を増やすことでプラズマ温度の低温度化と、アンテナ先端の高電界部とガスとの相互作用が増えるので、高い活性種の生成効率が実現でき、さらにはスロート部から末広部にガスを流すことで、低速でのプラズマ照射を実現できるプラズマ生成装置を提供することができる。
According to the above-described embodiment of the present invention, with such a configuration, the plasma temperature is lowered by increasing the gas flow rate in the high electric field portion at the tip of the antenna, and the high electric field portion at the tip of the antenna and the gas Therefore, it is possible to provide a plasma generation apparatus capable of realizing low-speed plasma irradiation by flowing gas from the throat portion to the diverging portion.
以上本発明の実施例について説明した。この構造は、絶縁筒５の内部が先細末広ノズル形状になっている点において特許文献１の構造と共通するが、大きく以下の２点で相違する。第１点は先細部２０１の入り口とスロート部２０２の入り口の間（別な言い方をすると先細部２０１内）にアンテナ１１の先端部１１ａが配置されていることであり、この点特許文献１のものはガス滞留部２００内にアンテナ１１の先端部１１ａが配置されている。また第２点は、アンテナ１１の形状であり、特許文献１では絶縁筒５の内部周囲に配置された２つのアンテナ間をガス流が通過するに対し、本発明では１つの棒状のアンテナの周囲をガス流が通過するようにされたことである。
The embodiments of the present invention have been described above. This structure is similar to the structure of Patent Document 1 in that the inside of the insulating cylinder 5 has a tapered and diverging nozzle shape, but it differs greatly in the following two points. The first point is that the tip portion 11a of the antenna 11 is arranged between the entrance of the tapered portion 201 and the entrance of the throat portion 202 (in other words, inside the tapered portion 201). A tip portion 11 a of the antenna 11 is arranged in the gas retention portion 200 . The second point is the shape of the antenna 11. In Patent Document 1, the gas flow passes between the two antennas arranged around the inside of the insulating cylinder 5. is to allow the gas stream to pass through.
以上、本発明者によってなされた発明を実施例に基づき具体的に説明したが、本発明は前記実施例に限定されるものではなく、その要旨を逸脱しない範囲で種々変更可能であることは言うまでもない。例えば、上記した実施例は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、各実施例の構成の一部について、他の構成の追加・削除・置換をすることが可能である。
Although the invention made by the present inventor has been specifically described above based on the embodiments, it goes without saying that the invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. stomach. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.
１：プラズマ生成部、３：外部導体、５：絶縁筒、５ａ：絶縁筒端部、１０：供給導体、１１：アンテナ、１１ａ：アンテナ先端部、４０ａ、４０ｂ：Ｏリング、５０：高周波電源、５１：同軸ケーブル、５２：同軸コネクタ、６０：ガス供給源、６１：ガス配管、６２：マスフローコントローラ、６３：ガス導入管、７０：保持導体、９０：プラズマ励起部、９１：プラズマ送出部、９２：ガス整流部、９９：プラズマ、２００：ガス滞留部、２０１：先細部、２０２：スロート部、２０３：末広部
1: plasma generator, 3: external conductor, 5: insulating cylinder, 5a: insulating cylinder end, 10: supply conductor, 11: antenna, 11a: antenna tip, 40a, 40b: O-ring, 50: high frequency power supply, 51: coaxial cable, 52: coaxial connector, 60: gas supply source, 61: gas pipe, 62: mass flow controller, 63: gas introduction pipe, 70: holding conductor, 90: plasma excitation section, 91: plasma delivery section, 92 : gas rectifying section, 99: plasma, 200: gas retention section, 201: tapered section, 202: throat section, 203: divergent section
Claims (5)
- プラズマ生成部の内部にガスを供給するガス供給源と、プラズマ生成部の内部に高周波電力を供給する高周波電源と、プラズマ生成部内に配置されてプラズマを発生する放電用アンテナを備えたプラズマ生成装置であって、
前記プラズマ生成部内の前記放電用アンテナとそれを囲む金属筐体との間に絶縁物を配置し、絶縁物の内部のガス流路が、ガス上流側から順にガス滞留部、先細部、スロート部、末広部で構成されており、前記放電用アンテナの先端が前記先細部の入口と前記スロート部との間に配置されていることを特徴とするプラズマ生成装置。 A plasma generating apparatus comprising a gas supply source for supplying gas to the inside of a plasma generating section, a high frequency power supply for supplying high frequency power to the inside of the plasma generating section, and a discharge antenna arranged in the plasma generating section for generating plasma. and
An insulator is arranged between the discharge antenna in the plasma generation section and a metal housing surrounding it, and the gas flow path inside the insulator is arranged in order from the upstream side of the gas retention section, the tapered section, and the throat section. , and a divergent portion, wherein the tip of the discharge antenna is arranged between the entrance of the tapered portion and the throat portion. - 請求項１に記載のプラズマ生成装置であって、
前記放電用アンテナは、前記絶縁物の内部のガス流路に沿って配置された１本のアンテナであり、前記放電用アンテナの外部をガスが流れることを特徴とするプラズマ生成装置。 The plasma generation device according to claim 1,
The plasma generation apparatus according to claim 1, wherein the discharge antenna is a single antenna arranged along a gas flow path inside the insulator, and gas flows outside the discharge antenna. - 請求項１に記載のプラズマ生成装置であって、
プラズマ送出部の背圧が大気圧であり、前記先細部と、前記スロート部と、前記末広部における、前記絶縁物内のガス流の流速が数ｍ／ｓであることを特徴とするプラズマ生成装置。 The plasma generation device according to claim 1,
Plasma generation characterized in that the back pressure of the plasma sending part is the atmospheric pressure, and the flow velocity of the gas flow in the insulator is several m/s at the tapered part, the throat part, and the diverging part. Device. - 請求項１に記載のプラズマ生成装置であって、
細胞培養に使われる有機材料で形成された培養基材を対象物としてプラズマ照射するようにされたことを特徴とするプラズマ生成装置。 The plasma generation device according to claim 1,
1. A plasma generating apparatus characterized by irradiating plasma on a culture substrate made of an organic material used for cell culture as an object. - 請求項４に記載のプラズマ生成装置であって、
プラズマ照射するときの速度は、プラズマの照射により対象物である培養基材が、飛散し移動しない速度とされていることを特徴とするプラズマ生成装置。 The plasma generation device according to claim 4,
A plasma generating apparatus, wherein the plasma irradiation is performed at a speed at which the culture substrate, which is an object, does not scatter and move due to the plasma irradiation.
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| JP2021-192822 | 2021-11-29 | ||
| JP2021192822A JP2023079376A (en) | 2021-11-29 | 2021-11-29 | Plasma generation device |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04351899A (en) * | 1991-05-28 | 1992-12-07 | Toyonobu Yoshida | Microwave heat plasma reaction device |
| US5573682A (en) * | 1995-04-20 | 1996-11-12 | Plasma Processes | Plasma spray nozzle with low overspray and collimated flow |
| JPH1027778A (en) * | 1996-07-09 | 1998-01-27 | Komatsu Ltd | Surface treating device and nozzle provided thereto |
| JP2010056002A (en) * | 2008-08-29 | 2010-03-11 | Nagano Japan Radio Co | Plasma treatment device |
-
2021
- 2021-11-29 JP JP2021192822A patent/JP2023079376A/en active Pending
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- 2022-09-12 WO PCT/JP2022/034027 patent/WO2023095420A1/en unknown
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04351899A (en) * | 1991-05-28 | 1992-12-07 | Toyonobu Yoshida | Microwave heat plasma reaction device |
| US5573682A (en) * | 1995-04-20 | 1996-11-12 | Plasma Processes | Plasma spray nozzle with low overspray and collimated flow |
| JPH1027778A (en) * | 1996-07-09 | 1998-01-27 | Komatsu Ltd | Surface treating device and nozzle provided thereto |
| JP2010056002A (en) * | 2008-08-29 | 2010-03-11 | Nagano Japan Radio Co | Plasma treatment device |
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