device for generating microwave radiation over a large area

Abstract

The invention relates to a microwave processing device (10), said microwave processing device (10) comprising: - a main module (100), extending from a base to a main end (102) along an elongation axis XX', the generating module being configured to emit a plasma jet in which a microwave field propagates, through an aperture (105) disposed at its main end (102); - a metallic grid (500), advantageously essentially planar, of extent S, and coupled to the main module (100) such that when the main module (100) is in operation, the plasma jet reaches said metallic grid (500) and the microwave radiation emitted by the main module (100) is absorbed by the metallic grid (500), which uniformly re-emits said radiation over its entire extent. Figure 1

Description

Title of the invention: Device for generating microwave radiation over a large surface area. FIELD OF THE INVENTION

[0001] The present invention relates to the field of microwave generators, particularly those combined with plasma generation. More specifically, the invention concerns a microwave generation device capable of emitting microwaves over a considerable surface area. The device according to the present invention is particularly intended for the treatment of skin and tissues for cosmetic, dermatological, and therapeutic procedures, usable on animals and humans or on any medium to be treated. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Plasma generating devices are now implemented in many fields, particularly in the medical field.

[0003] In this regard, US patent 11,264,211 B2 discloses a cold plasma generation device. This device, as illustrated in [Fig. 1] of US patent 11,264,211 B2, is provided with a cylindrical housing forming a cavity opening at one end of said housing. The device also includes a central electrode, generally elongated in shape and located within the cavity. In particular, the electrode terminates at one end with a pointed conical section accessible through the opening.

[0004] The device further comprises an inlet for a gas capable of forming a cold plasma when subjected to an electric field exceeding a so-called breakdown field. In particular, the device is configured to allow the gas to flow from the inlet to the conical section.

[0005] Finally, the device includes activation means configured to impose a voltage, greater than a breakdown voltage, so that the electric field in the vicinity of the tip of the conical section is greater than the breakdown field.

[0006] Thus, during operation, the gas is injected into the device through the inlet and flows towards the conical section, to which a voltage higher than the breakdown voltage is applied. Upon reaching the vicinity of the tip of the conical section, the gas ionizes under the effect of the electric field to form a plasma jet through the opening of the housing.

[0007] However, the extent of the plasma jet is relatively restricted so that its implementation remains limited to the treatment of small surfaces.

[0008] Furthermore, the implementation of such a device requires, for thermalization purposes, a relatively high gas flow rate—so that only a fraction of said gas is actually transformed, the rest of the gas escaping through the opening. However, the gases that can be used for plasma formation represent a relatively high financial cost that must be kept down.

[0009] Thus, one object of the present invention is to propose a device for generating a cold plasma and whose extent is appreciable.

[0010] Another object of the present invention is to propose a device for generating a cold plasma and whose gas consumption is optimized. BRIEF DESCRIPTION OF THE INVENTION

[0011] The present invention relates to a microwave processing device, said microwave processing device comprising:

[0012] - a main module, which extends from a base to a main end along a axis of elongation XX', the generation module being configured to emit microwaves, and a plasma jet, through an opening arranged at its main end;

[0013] - a metal grid, advantageously essentially flat, of an extent S, and coupled to the main module so that when the main module is in operation, the plasma jet reaches said metal grid and the microwave radiation emitted by the main module is absorbed by the metal grid which re-emits said radiation uniformly over said radiation over its entire extent.

[0014] According to one embodiment, a shielding layer is overlaying one face, called the main face, of the metal grid, the shielding layer comprising a dielectric layer and a metal layer, the dielectric layer being overlaying the main face of the metal grid and the metal layer being overlaying the dielectric layer, the metal layer and the dielectric layer comprising an opening through which the main module is coupled to the metal grid.

[0015] According to one embodiment, said device includes a coupling module configured to couple the main module and the metal grid.

[0016] According to one embodiment, the coupling module comprises a base and a coupling section, the base having an annular shape and is surmounted by one of its faces, called the upper face, by the coupling section, said section forming a cylinder into which the main module is inserted by its main end, and fixed in a sealed manner.

[0017] According to one embodiment, the coupling module is fixed to the metal grid by a face of the base, called the lower face, opposite to the upper face.

[0018] According to one embodiment, the coupling module is arranged to reinject the non-ionized main gas into the main module.

[0019] According to one implementation method, the main module comprises:

[0020] - an external cylindrical casing, which extends along the elongation axis, between an external base and the main end, and forming a housing, said housing being open at the main end;

[0021] - a central electrode of cylindrical shape, arranged coaxially to the housing external in the housing and extending from the external base to one of its ends called the free end, said central electrode comprising, at its free end, a tip, the central electrode defining with the external housing an annular space;

[0022] - means for injecting, into the dwelling, a principal gas capable of forming a cold plasma when it is subjected to an electric field greater than a so-called breakdown field;

[0023] - microwave means configured to transmit a microwave field to the central electrode, and such that said microwave field propagates in the annular space along the elongation axis XX' towards the opening, the tip ensuring the focusing of said microwave field so that the field near the tip is greater than the breakdown field.

[0024] According to one embodiment, the central electrode comprises at its free end a conical section.

[0025] According to one embodiment, the central electrode is hollow and forms a channel for the circulation of the main gas to the free end. Brief description of the drawings

[0026] Other features and advantages of the invention will become apparent from the detailed description that follows, with reference to the accompanying figures in which:

[0027] [Fig-1] Fig. 1 is a schematic representation, according to a perspective view, of a microwave processing device according to the present invention;

[0028] [Fig.2] The [Fig.2] is a schematic representation, according to a cross-sectional view, of a main module that can be implemented within the framework of the present invention;

[0029] [Fig.3] Fig.3 illustrates the implementation of a bandage or dressing covering the main face of the metal grid;

[0030] [Fig.4] The [Fig.4] illustrates the implementation of a useful layer covering the useful face of the metal grid;

[0031] [Fig.5] The [Fig.5] is an illustration of the implementation of a shielding layer;

[0032] [Fig.6] Fig.6 is an illustration of the implementation of a coupling module according to a perspective view;

[0033] [Fig.7] Fig.7 is an illustration of the implementation of a coupling module according to a cross-sectional view. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention relates to a microwave processing device, said microwave processing device comprising:

[0035] - a main module, which extends from a base to a main end according to an elongation axis XX', the main module being configured to emit a plasma jet in which a microwave field propagates, through an opening arranged at its main end;

[0036] - an essentially flat metallic grid, of extent S, and coupled to the module main so that when the main module is in operation, the plasma jet reaches said metal grid and the microwave radiation emitted by the main module is absorbed by the metal grid which re-emits said radiation uniformly over said radiation over its entire extent.

[0037] A schematic representation of the 10 microwave processing device according to the present invention can be seen in [Fig.1].

[0038] In particular, the processing device 10 includes a main module 100. This main module 100 is generally elongated in shape and therefore extends from a main base 101 to a main end 102 along an elongation axis XX'.

[0039] The main module 100 considered within the framework of the present invention is a cold plasma generation device. More particularly, the cold plasma generation device is configured to ionize a gas, referred to as the main gas, using microwaves.

[0040] In this regard, the figure is a schematic representation of a cold plasma generation device that can be implemented within the framework of the present invention.

[0041] However, the invention is not limited to the implementation of the device illustrated in [Fig.2],

[0042] In particular, the main module 100 comprises an external housing 110 extending along an elongation axis XX'. The external housing 110 is cylindrical in shape and extends from a base, referred to as the external base 101, to an end, referred to as the main end 102. Generally, the external housing 100 is laterally delimited by a lateral envelope 103, giving said external housing its cylindrical shape, and such that the latter forms a housing 104. The external housing 100 also comprises, at its main end 102, an opening 105.

[0043] It is understood that the housing 104, insofar as it is delimited by the external base 101 and the lateral envelope 103, is also cylindrical in shape and extends along the elongation axis XX' from the external base towards the opening 105.

[0044] The main module 100 also includes a central electrode 200 which is cylindrical in shape and extends along the elongation axis XX'. In particular, the central electrode 200 is arranged coaxially with the outer housing 110 in the housing 104 and so as to provide an annular space 300 between the central electrode 200 and the outer housing 110. More particularly, the central electrode 200 extends, along the elongation axis, from the outer base towards one of its ends, called the free end 201. In particular, the central electrode 200 terminates, at its free end, in a pointed section, and in particular of conical shape.

[0045] It is understood without the need to specify that the free end 201 is accessible through the opening 105.

[0046] Furthermore, according to the present invention, the electrode 200 can be hollow, and be configured to allow the flow of a gas and its evacuation through the free end 201.

[0047] The main module 100 further comprises means for injecting, into the housing, a primary gas capable of forming a cold plasma when subjected to an electric field exceeding a so-called breakdown field. This gas may comprise argon or a mixture comprising argon. However, the present invention is not limited to this aspect alone, and those skilled in the art may consider any other primary gas capable of fulfilling the desired function. In particular, the primary gas may comprise helium, nitrogen, or even dioxygen.

[0048] These injection means include, in particular, an inlet, referred to as the main inlet 106, through which the main gas can be injected. Depending on the variants considered, the main inlet 106 can be arranged to allow the injection of the main gas into the annular space 300 or into the central electrode 200.

[0049] The device also includes microwave transmission means 400 associated with a microwave generator (not shown). The microwave transmission means comprise a cylindrical section 410 attached at one end to the central electrode 200 (in other words, the cylindrical section and the central electrode form a single unit). In particular, the cylindrical section 410 is configured to allow microwaves from the microwave generator to be generated in the external housing 110. Those skilled in the art will find the information necessary for dimensioning the external housing, the central electrode, and the microwave transmission means in the US document 11,264,211 B2. The frequency of microwaves can be between 800 MHz and 50 GHz.

[0050] According to the present invention, the central electrode 200 and the cylindrical section 410 comprise a highly electrically conductive material such as copper, brass or silver.

[0051] Thus, the microwave transmission means 400 are configured to transmit a microwave field in the annular space 300 along the elongation axis XX' towards the opening. The free end of the central electrode 200, by its shape, focuses the microwave field so that the electric field in the vicinity of said free end increases substantially and, in particular, beyond the breakdown field.

[0052] The main gas, injected into the device through the main inlet 106, flowing in the vicinity of said end is then subjected to this electric field and then forms a plasma jet through the opening of the housing without it being necessary to apply a voltage and in particular a breakdown voltage of the gas in question.

[0053] The microwave processing device 10 also includes a metallic grid 500, advantageously essentially flat, of an extent S, and coupled to the main module so that when the main module is in operation, the plasma jet reaches said metallic grid and the microwave radiation emitted by the main module is absorbed by the metallic grid which re-emits said radiation uniformly over said radiation over its entire extent.

[0054] The metal grid 500 comprises two faces opposite each other, and said, respectively, main face 501 and useful face 502.

[0055] The metal mesh can be made of fine woven or non-woven metal wires. The metal wires preferably comprise metals with conductivity higher than that of brass, copper, aluminum, or silver. The metal wires may include a shallow metallic coating such as silver, gold, tin, or others. It is also possible to use a hybrid mesh in which the core is non-conductive and is coated with a thin conductive metallic layer. This non-conductive core can be a polymer, a composite material, or a natural fiber.

[0056] Thus, during operation, the main module generates an atmospheric P-plasma, assisted by microwaves, which strikes the metal grid 500 by its main face. In other words, the aperture 105 is directly above the main face 501.

[0057] When exposed to the microwave field contained in the plasma, the microwave field couples to the metallic mesh, which in turn acts as an antenna over its entire surface. This device, given the presence of the plasma jet P in contact with the metallic grid, does not induce arcing or sparking. Indeed, the weakly ionized plasma jet electrically neutralizes the metallic mesh, and prevents any accumulation of charge. The metal grid behaves like an antenna, and when its active face 502 is in contact with a surface to be treated, for example, the skin or any other part of a body, it couples the microwaves in the direction of the surface. Furthermore, due to impedance, the metal grid radiates only a small fraction of the microwaves from its main face. The microwaves coupled to the surface to be treated are absorbed by the water molecules of said surface. This coupling results in local heating of the surface to be treated, as well as improved blood circulation, among other physiological effects.

[0058] Advantageously, and as illustrated in [Fig. 3], a bandage 503 or dressing may be used to hold said metal grid against the surface to be treated. It is understood that said bandage or dressing shall include an opening to allow coupling of the plasma with the metal grid.

[0059] Advantageously, a contact layer 504, interposed between the metal grid and the surface to be treated, may be considered ([Fig. 4]). In other words, the contact layer 504 covers the working face 502. The working layer 504 may, in particular, be intended to protect the surface to be treated when the tissues forming it are weakened, especially in the case of a wound. The working layer 504 may comprise a thin adhesive, a hydrogel, or any other similar product.

[0060] Advantageously, a shielding layer can be used to cover the main face ([Fig. 5]). The shielding layer may comprise a flexible dielectric layer 505 and a metallic layer 506. Adhesives may be used to hold said layers 505 and 506 in place.

[0061] The metallic layer and the dielectric layer may include an opening through which the main module is coupled to the metallic grid.

[0062] The microwave treatment device 10 uses a main gas, for example argon or a noble gas, the consumption of which should be limited. Indeed, the ionization at the free end of the central electrode only concerns a small fraction of the main gas actually injected into the main module.

[0063] In order to overcome this effect, it may be considered to implement a coupling module 600 ([Fig.6] and [Fig.7]).

[0064] In particular, the coupling module 600 comprises a base 610 and a coupling section 620. The base 610 having an annular shape and is surmounted by one of its faces, called upper face 611, by the coupling section 620, said section forming a cylinder into which the main module is inserted by its main end, and fixed in a sealed manner.

[0065] The coupling module 600 is fixed to the metal grid by a face of the base, called the lower face 612, opposite the upper face 611.

[0066] The coupling module is also arranged to reinject the non-ionized main gas into the main module. In particular, the electrode can be hollow and arranged to allow the circulation of the main gas within its volume and to the free end where the main gas, under the influence of the surrounding electric field generated by the microwaves, is ionized to form a plasma jet. The main module can also include an outlet coupled, for example, to a recirculation means, such as a pump. The outlet, communicating directly with the annular space, thus allows the recovery of the non-ionized main gas fraction. This last consideration makes it possible to consider recirculating the non-ionized main gas and thereby reduce main gas consumption.

[0067] All the advantageous embodiments presented in the statement of the invention can be taken individually or in combination.

[0068] Of course, the invention is not limited to the embodiments described and alternative embodiments can be made without departing from the scope of the invention as defined by the claims.

Claims

Demands

1. Microwave processing device (10), said microwave processing device (10) comprising: - a main module (100), which extends from a base to a main end (102) along an elongation axis XX', the main module being configured to emit a plasma jet in which a microwave field propagates, through an opening (105) disposed at its main end (102); - a metallic grid (500), advantageously essentially planar, of an extent S, and coupled to the main module (100) such that when the main module (100) is in operation, the plasma jet reaches said metallic grid (500) and the microwave radiation emitted by the main module (100) is absorbed by the metallic grid (500) which re-emits, over its entire extent and uniformly, said radiation.

2. Device according to claim 1, wherein a shielding layer is covering a face, referred to as the main face (501), of the metal grid (500), the shielding layer comprising a dielectric layer and a metal layer, the dielectric layer being covering the main face (501) of the metal grid (500) and the metal layer being covering the dielectric layer, the metal layer and the dielectric layer comprising an opening (105) through which the main module (100) is coupled to the metal grid (500).

3. Device according to claim 2, wherein said device comprises a coupling module (600) configured to couple the main module (100) and the metal grid (500).

4. Device according to claim 3, wherein the coupling module (600) comprises a base (610) and a coupling section (620), the base having an annular shape and is surmounted by one of its faces, called upper face (611), by the coupling section, said section forming a cylinder into which the main module (100) is inserted by its main end (102), and fixed in a sealed manner.

5. Device according to claim 4, wherein the coupling module (600) is fixed to the metal grid by a face of the base, referred to as the lower face, opposite to the upper face.

6. Device according to claim 5, wherein the coupling module (600) is arranged to reinject the non-ionized main gas into the main module (100).

7. Device according to claim 6, wherein the main module (100) comprises: - an external housing (110) of cylindrical shape, which extends along the elongation axis, between an external base and the main end (102), and forming a housing (104), said housing (104) being open through the main end (102); - a central electrode (200) of cylindrical shape, disposed coaxially with the external housing (110) in the housing (104) and which extends from the external base towards one of its ends called the free end (201), said central electrode (200) comprising, at its free end (201), a tip, the central electrode (200) defining with the external housing (110) an annular space (300); - means for injecting, into the housing (104), a main gas capable of forming a cold plasma when it is subjected to an electric field greater than a so-called breakdown field;- microwave means (400) configured to transmit a microwave field to the central electrode (200), and such that said microwave field propagates in the annular space (300) along the elongation axis XX' towards the aperture (105), the tip ensuring the focusing of said microwave field so that the field near the tip is greater than the breakdown field.

8. Device according to claim 7, wherein the central electrode (200) comprises at its free end (201) a conical section.

9. Device according to any one of claims 7 or 8, wherein the central electrode (200) is hollow and forms a channel for the circulation of the main gas to the free end (201).

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