EP3346806B1

EP3346806B1 - Atmospheric-pressure plasma generation device with light emitting device

Info

Publication number: EP3346806B1
Application number: EP15903005.5A
Authority: EP
Inventors: Takahiro Jindo
Original assignee: Fuji Corp
Current assignee: Fuji Corp
Priority date: 2015-09-02
Filing date: 2015-09-02
Publication date: 2020-07-22
Anticipated expiration: 2035-09-02
Also published as: EP3346806A4; JPWO2017037885A1; EP3346806A1; WO2017037885A1; JP6587689B2

Description

Technical Field

The present invention relates to an atmospheric pressure plasma generating device that emits plasma from an emission port.

Background Art

With an atmospheric pressure generating device, by emitting plasma from an emission port towards a target body, plasma is applied to the target body such that processing is performed. An example of a plasma generating device is disclosed in JP-A-2012-059548 . US 2003/0125727 A1 discloses a medical instrument wherein an initial plasma volume is formed by irradiating a captured neutral gas volume with a high intensity wavelength, within the UV spectrum defined as from 10 nm to 400 nm. Thereafter, an intense application of energy is applied to a targeted surface layer by creating an ultrafast high-intensity electrical discharge within the ionized gas volume and the surface layer to cause an electrochemical volatilization of molecules of the surface layer, i.e., a plasma-mediated ablation. US 2015/0038790 A1 discloses an endoscope used to apply cold plasma for treatment. The cold plasma is generated at a distal end of the endoscope. A fiber carries a laser beam through an output tube of the endoscope, the laser being used for cutting tissue and/or blood coagulation.
Atmospheric pressure plasma generating devices according to the preamble of independent claim 1 are disclosed in US 2014/0188195 A1 and EP 2 308 415 A1 . In US 2014/0188195 A1 , an array of light sources that project converging light beams are used with a cold plasma treatment device to control a treatment distance without contacting the patient or increasing the risk of pathogenic contamination. In EP 2 308 415 A1 , a plasma jet applying device for dentistry is configured such that a generated plasma jet is emitted from a plasma jet application orifice and applied to an affected area during treatment. The plasma jet applying device also has an optical fiber configured to perform light irradiation with visible light from the vicinity of the plasma jet application orifice toward an affected area during treatment in order to effect a photopolymerization of a resin.

Summary of Invention

Technical Problem

According to the atmospheric plasma generating device disclosed in JP-A-2012-059548 , it is possible to perform plasma processing on a target body. However, because it is not possible to check plasma visually, there are cases in which plasma is not applied appropriately to the target body. The present invention takes account of such circumstances and an object thereof is to appropriately apply plasma to a target body.

Solution to Problem

To solve the above problems, the present invention provides an atmospheric pressure plasma generating device according to claim 1, as well as a system according to claim 3.
A preferred embodiment of the present invention is defined in claim 2.

Advantageous Effects

With the disclosed atmospheric pressure plasma generating device, light is emitted in the emission direction of the plasma from the emission port. Accordingly, due to the light, it is possible to visually check the plasma emission position, and it is possible to appropriately apply plasma to a target body.

Brief Description of Drawings

[Fig. 1]
Fig. 1 is a perspective view showing a plasma emitting device of a first embodiment.
[Fig. 2]
Fig. 2 is an exploded view of the plasma emitting device of fig. 1.
[Fig. 3]
Fig. 3 is a perspective view showing a plasma emitting device of a second embodiment.
[Fig. 4]
Fig. 4 is a cross section of line AA shown in fig. 3.

Description of Preferred Embodiments

The following describes in detail referring to the figures an example embodiment of the present invention.

First embodiment

Configuration of plasma emitting device

Fig. 1 shows an embodiment of the present invention, plasma emitting device 10. Plasma emitting device 10 is for emitting plasma to a target body. Plasma emitting device 10 is provided with main body section 12, pair of electrodes 14 and 16, glass pipe 18, gas supply device 20, and laser emitting device 22.
Main body section 12 is formed from sapphire glass and is configured from cylindrical section 23 and bent section 24. Cylindrical section 23 is substantially a round tube. Bent section 24 is bent into an L-shape, and an end section thereof is connected in an upright state to an outer surface of cylindrical section 23 near the other end of cylindrical section 23. Note that, the inside of cylindrical section 23 and the inside of bent section 24 are linked.
Also, multiple electrical discharge sections 26 and 28 of the pair of electrodes 14 and 16 are vacuum deposited on the outer circumferential surface of cylindrical section 23 of main body section 12 so as to be lined up alternately in an axis direction of cylindrical section 23. In detail, as shown in fig. 2, electrode 14 includes multiple electrical discharge sections 26 and connecting sections 30, and electrode 16 includes multiple electrical discharge sections 28 and connecting sections 32. Note that, fig. 2 is a theoretical view showing electrodes 14 and 16 removed from cylindrical section 23.
The multiple electrical discharge sections 26 of electrode 14 are vacuum deposited on the outer circumferential surface of cylindrical section 23 extending in the circumferential direction, and are arranged at a specified interval lined up in the axis direction of cylindrical section 23. Also, connecting sections 30 of electrode 14 are vacuum deposited on the outer circumferential surface of cylindrical section 23 extending in a line in the axis direction of cylindrical section 23, and are connected to the multiple electrical discharge sections 26. Note that, from among the multiple electrical discharge sections 26 of electrode 14, electrical discharge section 26 positioned at one end is vacuum deposited around the entire circumference in the circumferential direction of cylindrical section 23; the other electrical discharge sections 26 are vacuum deposited extending in the circumferential direction of cylindrical section 23, except for a portion on the opposite side to connecting section 30. Also, current passing section 36 is formed on the electrical discharge section 26 vacuum deposited across the entire circumference in the circumferential direction of cylindrical section 23 protruding from an end of cylindrical section 23.
Further, the multiple electrical discharge sections 28 of electrode 16 are vacuum deposited on the outer circumferential surface of cylindrical section 23 extending in the circumferential direction, and are arranged lined up in the axis direction of cylindrical section 23 so as to be positioned between the multiple electrical discharge sections 26 of electrode 14. Note that, from among the multiple electrical discharge sections 28 of electrode 16, electrical discharge sections 28 positioned between two of the electrical discharge sections 26 of electrode 14 are vacuum deposited extending in the circumferential direction of cylindrical section 23 excluding connecting section 30 of electrode 14; the remaining electrical discharge sections 28 positioned at the ends are vacuum deposited across the entire circumference in the circumferential direction of cylindrical section 23. Current passing section 38 is formed on the electrical discharge section 28 vacuum deposited across the entire circumference in the circumferential direction of cylindrical section 23 protruding from an end of cylindrical section 23. Also, connecting sections 32 of electrode 16 are vacuum deposited on the outer circumferential surface of cylindrical section 23 extending in a line in the axis direction of cylindrical section 23 at locations where electrical discharge sections 26 of electrode 14 are not vacuum deposited, and are connected to the multiple electrical discharge sections 28. Thus, the pair of electrodes 14 and 16 have electrical discharge sections 26 of electrode 14 and electrical discharge sections 28 of electrode 16 vacuum deposited on the outer circumferential surface of cylindrical section 23 lined up alternately with a specified gap between them.
As shown in fig. 1, glass tube 18 is arranged on the outer circumferential surface of cylindrical section 23 of main body section 12 so as to entirely cover the pair of electrodes 14 and 16 vacuum deposited on the outer circumferential surface of main body section 12. By this, it is possible to prevent exposure of electrodes 14 and 16, through which high voltage is applied, thereby maintaining safety. Note that, because electrodes 14 and 16 are encased by glass pipe 18, glass pipe 18 encroaches in between electrical discharge sections 26 of electrode 14 and electrical discharge sections 28 of electrode 16.
Gas supply device 20 supplies processing gas and is connected to an end of bent section 24 opposite to an end of bent section that is connected to cylindrical section 23. Thus, processing gas is supplied inside cylindrical section 23 via bent section 24. Note that, processing gas may be gas in which an inert gas such as nitrogen is mixed with active gases in the air such as oxygen at a given ratio, or may be only an inert gas, or only air. Also, gas supply device 20 may also be provided with a function to heat or cool the processing gas, such that processing gas can be supplied at a given temperature.
Laser emitting device 22 emits laser light and is substantially a short cylinder. An end surface of laser emitting device 22 is axially connected to an end surface of cylindrical section 23 at which bent section 24 is arranged. Note that, laser emitting device 22 is removably attached to cylindrical section 23. Also, in a central portion of the end surface of laser emitting device 22 connected to cylindrical section 23, emitting hole 40 (refer to fig. 2) is formed, and laser emitting device 22 emits laser light from emitting hole 40 in an axial direction of cylindrical section 23. Note that, the laser light is laser light of long wavelength visible light and of an ultraviolet region.
Also, as shown in fig. 2, laser emitting device 50 different to laser emitting device 22 is prepared. Laser emitting device 50 has the same dimensions as laser emitting device 22, such that by removing laser emitting device 22 from cylindrical section 23, laser emitting device 50 can be connected to cylindrical section 23 instead of laser emitting device 22. Note that, similar to laser emitting device 22, laser emitting device 50 emits laser light, but the laser light emitted by laser emitting device 50 is long wavelength visible light that does not include ultraviolet light.

Emitting plasma using the plasma emitting device

According to the above configuration, plasma emitting device 10 emits plasma from an end of cylindrical section 23, so as to apply plasma to a target body. In detail, processing gas from gas supply device 20 is supplied inside cylindrical section 23 via bent section 24. Because the end of cylindrical section 23 on which bent section 24 is arranged is covered by laser emitting device 22, processing gas supplied to cylindrical section 23 flows from that end towards the opposite end. That is, processing gas flows towards the inside of cylindrical section 23 on which electrodes 14 and 16 are vacuum deposited.
Then, current passing sections 36 and 38 apply voltage to electrodes 14 and 16, such that current flows through electrodes 14 and 16. By this, electrical discharge is generated between electrical discharge sections 26 and 28 of the pair of electrodes 14 and 16. Here, because electrodes 14 and 16 are encased by glass pipe 18, which is an insulating body, electrical discharge is generated inside cylindrical section 23 such that the processing gas flowing inside cylindrical section 23 is plasmarized. Thus, plasma is emitted in an axial direction of cylindrical section 23 from an opening (also referred to as an "emission port") of cylindrical section 23 formed in an end surface of cylindrical section 23 opposite to an end of cylindrical section 23 to which laser emitting device 22 is connected. Thus, plasma is applied to a target body arranged along the line of the emission direction of the plasma.
However, because the wavelength of the plasma is in a vacuum ultraviolet range, it cannot be checked visually. Therefore, there are cases in which plasma is not applied appropriately to the target body. Considering this point, plasma emitting device 10 is provided with laser emitting device 22, and by the laser light emitted by laser emitting device 22, the emission position of plasma can be checked.
In detail, as described above, laser emitting device 22 is connected to an end surface of cylindrical section 23, and emits laser light in an axial direction of cylindrical section 23. That is, laser emitting device 22 emits laser light axially to the emission direction of plasma. Also, laser light is directional light that travels straight. Thus, the laser light emitted from laser emitting device 22 passes through cylindrical section 23 and is emitted from the emission port of cylindrical section 23 axially to the emission direction of the plasma. Thus, the laser light is emitted at a location at which plasma is applied to the target body. Because the wavelength of the laser light applied to the target body includes a wavelength is a visible range, an operator can visually check the laser light. Thus, due to the laser light, an operator can check the emission position of the plasma to ensure that plasma is appropriately applied to the target body.
Also, with plasma emitting device 10, laser emitting device 22 is arranged at an upstream location to where the processing gas is plasmarized. In detail, processing gas is supplied inside cylindrical section 23 from gas supply device 20 via bent section 24. And, processing gas supplied inside cylindrical section 23 flows towards the emission port. Here, the processing gas is plasmarized between a location where bent section 24 is connected to cylindrical section 23 and the emission port. Laser emitting device 22 is connected to the end of cylindrical section 23 opposite to the emission port. Thus, laser emitting device 22 is arranged at an upstream location to where the processing gas is plasmarized. Therefore, laser emitting device 22 is exposed to processing gas, but is not exposed to plasma. This prevents plasma being applied to laser emitting device 22.
Note that, emitting of plasma by plasma emitting device 10 is performed after the emission location is confirmed by laser light. In detail, first, laser light is emitted by laser emitting device 22. Here, supply of processing gas from gas supply device 20 and applying of voltage to electrodes 14 and 16 are not being performed. Thereby, an operator points the emission port of cylindrical section 23 towards the target body to align the planned plasma emitting position with the laser light. Once the planned plasma emitting position is aligned with the laser light, processing gas is supplied by gas supply device 20, and voltage is supplied to electrodes 14 and 16. By this, plasma can be suitably emitted to the planned plasma emission position.
Plasma includes reactive oxygen radicals, and the target body to which plasma is applied is activated at the surface, such that plasma can be applied to a target body for various purposes. In detail, for example, in a medical field, skin can be activated by applying plasma to the skin for the purpose of generating the skin. Also, for example, by applying plasma to bone, the surface of the bone becomes more hydrophilic, which improves bonding strength of adhesive. Thus, plasma can be applied for the purpose of bonding bone. Further, for example, in an industrial field, plasma can be applied for the purposes of surface processing and surface improvement of metals or the like. In this manner, technology for applying plasma is used in various fields.
Due to the above, the emission temperature of the plasma is adjusted depending on the purpose of applying plasma. Specifically, for example, in a case of applying plasma to regenerate skin, processing gas with a relatively low temperature is supplied by gas processing device 20. Therefore, the emission temperature of the plasma can be made appropriate for applying to skin. Also, for example, in a case of applying plasma to bone, metal, or the like, processing gas with a relatively high temperature is supplied by gas supply device 20. Thus, the emission temperature of the plasma is high, and effective plasma processing can be performed.
Also, as described above, laser emitting device 22 emits laser light of long wavelength visible light and of an ultraviolet region. Thus, the surface of the target body to which the laser light is applied is activated by ultraviolet light. That is, the surface of the target body is also activated by the laser light that is used for checking the emission position of the plasma. By this, the surface of the target body can be activated by the laser light and the plasma, such that effective surface processing can be performed on the target body. However, there are target bodies to which it is not desirable to apply ultraviolet light. Therefore, as described above, with plasma emitting device 10, laser emitting device 50 can be attached to plasma emitting device 10 instead of laser emitting device 22. Laser emitting device 50 emits laser light of long wavelength visible light that does not include ultraviolet light. Thus, it is possible to apply laser light and to check the emission position of plasma even for a target body to which it is not desirable to apply ultraviolet light.

Second embodiment

Figs. 3 and 4 show a second embodiment of the plasma emitting device 70. Plasma emitting device 70 is provided with main body section 72, earth plate 74, emitting nozzle 76, pair of electrodes 78 and 80, and laser emitting device 82. Note that, in fig. 3, the main sections of plasma emitting device 70 are shown as transparent, and fig. 4 is a cross section along the line A-A of fig. 3. Also, for clarity, laser emitting device 82 is not shown in fig. 3.
Main body section 72 is approximately cuboid, and is formed from a ceramic. Reaction chamber 86 is formed inside main body section 72. Four first flow paths 88 are formed at a bottom surface of reaction chamber 86 extending down. Note that, first flow paths 88 do not open to the lower surface of main body section 72. Also, second flow paths 90 that open to the front surface of main body section 72 are formed in main body 72 from the lower end of first flow paths 88. The end of second flow paths 90 on the front side of main body section 72 are blocked by plugs 96. Further, third flow paths 98 that pierce second flow paths 90 in a vertical direction between both ends of flow paths 90 are formed in main body section 72. Note that, an upper end section of third flow path 98 does not open at a top surface of main body section 72, but a lower end of third flow path does open on a lower surface of main body section 72.
Earth plate 74 is formed from metal, and is fixed to a lower surface of main body section 72. Four through-holes 100 that run in a vertical direction are formed in earth plate 74, with through-holes 100 being connected to third flow paths 98 of main body section 72 in a coaxial manner.
Emitting nozzle 76 is fixed to a lower surface of earth plate 74. Four nozzle holes 102 that run in a vertical direction are formed in emitting nozzle 76, with nozzle holes 102 being connected to through-holes 100 of earth plate 74 in a coaxial manner.
The pair of electrodes 78 and 80 are rod shaped, and are inserted into reaction chamber 86 in a state separated from each other. Also, laser emitting device 82 is arranged inside main body section 72 and is connected to an upper end of third flow path 98. Laser emitting device 82 is a device for emitting laser light, and emits laser light in an axial direction of third flow path 98.
According to such a construction, plasma emitting device 70 emits laser light from an opening (also referred to as emission port) at the lower end of nozzle hole 102 of emitting nozzle 76, and that laser light is used to emit plasma to a planned plasma emission position. In detail, first, laser light is emitted by laser emitting device 82 along an axial direction of third flow path 98. Thus, laser light is emitted from the emission port via third flow path 98, through-hole 100, and nozzle hole 102. Thereby, an operator points the emission port towards the target body to align the laser light with the planned plasma emitting position.
Continuing, processing gas is supplied to reaction chamber 86, and voltage is applied to the pair of electrodes 78 and 80. Thus, current flows between the pair of electrodes 78 and 80, an electrical discharge occurs, and the processing gas is plasmarized by the electrical discharge. Then, the plasma is emitted from the emission port via first flow path 88, second flow path 90, through-hole 100, and nozzle hole 102. Here, the emission direction of the plasma is the axial direction of second flow path 90, through-hole 100, and nozzle hole 102. Thus, plasma is emitted towards the laser light being applied to the target body. In this manner, with second embodiment plasma emitting device 70, too, similar to with first embodiment plasma emitting device 10, the plasma emission position can be checked with the laser light, and plasma can be appropriately applied to the planned plasma emission position.
Note that, plasma emitting device 10 is an example of an atmospheric pressure plasma generator. Main body section 12 is an example of a flow path. Electrodes 14 and 16 are examples of an electrode. Gas supply device 20 is an example of a supply device. Laser emitting device 22 is an example of an emitting device. Laser emitting device 50 is an example of an emitting device. Plasma emitting device 70 is an example of an atmospheric pressure plasma device. Electrodes 78 and 80 are examples of an electrode. Laser emitting device 82 is an example of an emitting device. First flow path 88, second flow path 90, through-hole 100, and nozzle hole 102 are examples of a flow path.
Further, the present invention is not limited to the above example embodiments, and other embodiments are possible within the scope of the invention, which is defined in the claims. Specifically, for example, in an embodiment above, laser light is used as a light emitted to the target body, but various types of light may be used, as long as the light is visible. However, to appropriately check the plasma emission position, it is desirable to use light with excellent straightness and convergence properties, that is, so-called directional light.

Reference Signs List

10: plasma emitting device (atmospheric pressure plasma generator); 12: main body section (flow path); 14: electrode; 16: electrode; 20: gas supply device (supply device); 22: laser emitting device (emitting device); 50: laser emitting device (emitting device);70: plasma emitting device (atmospheric pressure plasma generator); 78: electrode; 80: electrode; 82: laser emitting device (emitting device); 88: first flow path (flow path); 90: second flow path (flow path); 100: through-hole (flow path); 102: nozzle hole (flow path)

Claims

An atmospheric pressure plasma generating device (10;70) comprising:
an opening from which plasma is emitted, and a first remitting device (22;82) configured to emit light comprising visible light,

characterized in that

the emitting device is configured to emit said light comprising visible light from said opening in the emission direction of the plasma.
The atmospheric pressure plasma generating device (10) according to claim 1, including a supply device (20) configured to supply processing gas,
a flow path (12) for the processing gas configured such that said processing gas supplied from the supply device (20) flows towards said opening, and
an electrode (14,16) for applying an electric current to the processing gas in the flow path such that plasma is generated,
wherein the first emitting device (22) is provided further on an upstream side than a location of the flow path (12) at which the processing gas is plasmarized by the electrode (14,16).
A system comprising;
the atmospheric pressure plasma generating device (10) according to claim 1 or 2, wherein the light emitted by said first emitting device (22) also comprises ultraviolet light;
wherein said first emitting device (22) is attached in a replaceable manner to said atmospheric plasma generating device (10);
wherein said system further comprises a second emitting device (50) being removably attachable to said atmospheric plasma generating device (10) instead of said first emitting device (22);
wherein said second emitting device (50) is configured to emit light comprising visible light but not ultraviolet light.