JP2010536123A - Pulse plasma apparatus and method for generating pulsed plasma - Google Patents

Abstract

An apparatus and method for generating a truly pulsed plasma stream is disclosed. The apparatus includes a cathode assembly comprising a cathode and a cathode holder, an anode, and two or more intermediate electrodes, forming a plasma channel in which the anode and the intermediate electrodes extend toward the anode. The intermediate electrode closest to the cathode forms a plasma chamber around the cathode tip. An extension nozzle that forms an extension channel with a tubular insulator along at least a portion of the inner surface is attached to the anode end of the device. In operation, a voltage is applied between the cathode and anode, and current is passed through the cathode, plasma, and anode. The voltage profile and current profile are selected to cause a rapid generation of a plasma flow with the required characteristics. A substantially uniform temperature and power density distribution of the plasma pulse is achieved in the extension nozzle. Furthermore, ozone may be generated in the extension nozzle during the generation of the plasma pulse.
[Selection] Figure 2A

Description

  The present invention relates to a plasma generation apparatus, and more particularly to a plasma generation apparatus and method for generating pulsed plasma for applications that require pure plasma.

  Plasma generators play an important role in many fields. For example, plasmas are used in displays such as television sets and computer monitors, spectrophotography, spray applications such as coatings, and medicine.

  It is well known that plasma can be used effectively in the medical field for tissue ablation, coagulation and vaporization. For best results, the generated plasma needs to have accurate characteristics such as speed, temperature, energy density and the like. Preferably, the plasma used for medical applications should be pure. In other words, the plasma contains only particles of the ionized plasma generating gas and should not contain other particles such as materials that are separated from various parts of the plasma generating device during operation.

  Recently, attempts have been made to use plasma for tissue treatment, particularly skin treatment. The plasma has various effects when in contact with the skin surface, particularly depending on the temperature rise that the plasma creates on the surface of the skin. For example, if the temperature is raised by about 35 to 38 ° C., there is an effect of removing wrinkles. Increasing the temperature by about 70 ° C removes the epidermis and may be useful in cosmetic surgery. It has been found that a continuous plasma flow suitable for tissue ablation, coagulation and vaporization is generally not suitable for other types of tissue treatment, and in particular not for skin treatment. Instead, pulsed plasma is used to avoid undesirable skin damage that would result from using a continuous plasma flow. Two types of devices used for this purpose are currently known.

  The apparatus disclosed in Patent Document 1 is an example of the first type. In this type of device, the plasma is generated by passing an alternating magnetic field through a plasma generating gas such as nitrogen. An alternating magnetic field produces a fast movement of free electrons in the gas. The rapidly moving electrons knock out other electrons from the gas atoms and form so-called electron avalanches, which in turn cause a corona discharge. A pulse corona discharge is generated by applying an electric field in pulses. The advantages of this method of generating a pulsed corona discharge among others are (1) the absence of impurities in the flow, and (2) a short start time that allows the generation of a truly pulsed flow. is there. For purposes of this disclosure, a truly pulsed flow refers to a flow that stops completely during the off period of the pulse.

  The disadvantage of the first type of apparatus and method is that the generated corona discharge has a constant maximum temperature of about 2000 ° C. The corona discharge formed in the device never becomes a hot plasma. In order to obtain the 1 to 4 joules of energy required to denature collagen during skin treatment with this type of device, the velocity of the plasma-generated gas flow must be relatively high. For example, using argon in such an apparatus requires a flow of about 20 liters per minute to obtain the required energy. Such a flow rate is not feasible due to skin treatment. When nitrogen is used to generate a plasma, the required energy can be obtained at a flow rate of only about 5 liters per minute, but even this rate causes discomfort to the patient. Thus, the application of the first type of device is limited by the nature of the electrical discharge process that can cause a corona discharge.

  A second type of device generates plasma by heating a flow of plasma-generating gas that passes through the plasma channel by an electric arc created between the cathode and the anode that forms the plasma channel. An example of the second type of device is disclosed in US Pat. According to the disclosure of U.S. Pat. No. 6,057,049, a pulsed DC voltage is applied between the anode and cathode when a plasma generating gas, preferably argon, traverses the plasma channel. A predetermined constant bias voltage may or may not be added to the pulsed DC voltage. During the voltage pulse, the number of free electrons in the plasma generating gas increases, resulting in a decrease in the resistance of the plasma and an exponential increase in the current flowing in the plasma. During the off period, the number of free electrons in the plasma product gas decreases, resulting in an increase in plasma resistance and an exponential decrease in the current flowing through the plasma. The current is relatively low during the off period, but the current never disappears completely. This low current, called standby current, is undesirable because no truly pulsed flow is generated. During the off period, a continuous low power plasma flow is maintained. In essence, the device does not generate a pulsed plasma, but generates a continuous plasma flow with power spikes called pulses, thereby simulating the pulsed plasma. Since the off period is substantially longer than the pulse, the device outputs a significant amount of energy during the off period, and therefore the device is effectively utilized for applications that require a truly pulsed plasma flow. I can't. For example, if the device is used for skin treatment, the device may be separated from the skin surface after each pulse so that the skin is not exposed to low power plasma during the off period . This detracts from the usefulness of the device.

  Reducing the current through the plasma to zero between pulses and restarting the device with each plasma pulse is not practical when using the device disclosed in US Pat. Restarting the device after each pulse does not guarantee that the cathode arc attachment is well controlled and results in rapid destruction of the cathode as a result of high current passing through the cathode.

  The device disclosed in US Pat. No. 6,057,056 and other devices of this type that are now known do not have the ability to generate a truly pulsed plasma stream that can be safely used by patients. This is due to the configuration of the device. It takes several milliseconds to reach the plasma flow stage after the off period. During this few milliseconds, the device cannot be used on the patient because the plasma properties are not easily controlled. In addition, when this type of device starts up, there is some electrode corrosion due to sputtering. This corrosion results in a separate electrode material that flows in the plasma. When a continuous plasma flow is used, activation impurities are a relatively unimportant drawback because activation and associated impurities occur only once per treatment. Thus, it is possible to wait a few seconds after startup for the electrode material to exit the device before the device begins the actual treatment. However, when using a pulsed plasma flow, it is not practical to wait for impurities to escape from the device. This is because the next pulse of plasma must be generated before the waiting time is over.

  When the plasma stream is pre-created, it takes only a few microseconds to increase or decrease the current in the plasma stream. Furthermore, since there is no start up, impurities do not enter the plasma flow and the cathode is not stressed. However, maintaining a low current through the plasma continuously, even at low currents, is optimal for some applications that require a truly pulsed plasma flow, as described above. It is not a state device.

  The difficulty of generating a truly pulsed plasma stream by heating the plasma generating gas with an electric arc is mainly due to the nature of the process occurring at the electrodes. In general, and especially for medical applications, it is important to ensure operation without erosion of the anode and cathode when the current increases rapidly. During rapid current increases, the cathode temperature is low and may not be easily controlled during the repetition of subsequent pulses. When creating an electric arc between the cathode and anode, the area of attachment of the arc to the cathode is highly dependent on the initial temperature of the cathode. When the cathode is cold, the area of attachment is relatively small. After a few pulses, the temperature of the cathode rises so that during the period of rapid current increase, the attachment area expands to the entire surface area of the cathode and then to the cathode holder. Under these circumstances, the cathode potential begins to fluctuate and cathodic corrosion begins. Furthermore, if the area of attachment of the electric arc reaches the cathode holder, the cathode holder begins to melt and introduces unwanted impurities into the plasma stream.

  A similar situation occurs at the surface of the anode. When the current in the arc increases rapidly, the plasma flow does not have enough time to reach high temperatures. As a result, the plasma concentration close to the anode surface is low. This causes a decrease in anode potential and potential variations that cause severe corrosion of the cathode. Variations in the cathode and anode potentials cause the energy of the pulsed plasma flow to be unstable and not easily controlled.

US Pat. No. 6,629,974 US Pat. No. 6,475,215

  In order for the cathode to function properly, it is necessary to control the exact location and size of the region of attachment of the electric arc to the cathode surface during the period of rapid current increase in each pulse of the plasma. Also, for proper functioning of the anode, it is necessary to create a heated plasma flow at the surface of the anode during the period of pulse operation as well as during rapid current increases.

  Generating a truly pulsed plasma, especially for medical applications, causes several additional problems. First, as described above, the plasma needs to be pure and free of any electrode material or other impurities. Secondly, the characteristics of the generated pulses of the plasma need to be controlled. Initially, the energy transferred by the pulse can be controlled by controlling the duration, voltage and current of the pulse. In some applications, such as skin treatment, it is not sufficient to simply control the energy converted into pulses, and the energy and temperature should be distributed substantially uniformly throughout the area to be treated.

  Thus, currently known devices by generating a truly pulsed plasma containing a minimal amount of impurities and distributing the energy converted into each pulse substantially uniformly throughout the treatment site. There is a need for a device that overcomes these limitations. In addition, there may be applications that require the device to possibly be able to supply ozone to the treatment surface and to be able to remove fluids and other foreign objects from the treatment surface.

  As shown in the drawings, the pulsed plasma apparatus of the present invention comprises a cathode assembly including one or more cathodes attached to a cathode holder, an anode, and two or more intermediate electrodes. The anode and intermediate electrode form a plasma channel. The intermediate electrode closest to the cathode further forms a plasma chamber around the cathode end closest to the anode. The plasma channel comprises three parts: a heating part, an enlarged part and an anode part. The enlarged portion has two or more enlarged sections. The diameter of each successive section of the enlarged portion increases towards the anode. The anode portion has a diameter that is greater than the diameter of the enlarged portion closest to the anode. The cathode holder prevents cathode displacement, and preferably keeps the cathode parallel to the axis of the device, thus preventing angular displacement of the cathode.

  The extension nozzle is attached to the anode end of the device. The extension nozzle forms an extension channel connected to the plasma channel. The tubular insulator element covers the longitudinal portion of the inner surface of the extension channel. Further, in some embodiments, the extension nozzle has one or more oxygen carrying gas inlets.

  During operation, a truly pulsed plasma is generated by the device. For each pulse, the plasma goes through three stages: a spark discharge, a glow discharge, and an arc discharge. In an exemplary embodiment, the spark discharge is created by applying a high frequency, high amplitude voltage wave between the cathode and anode. After a spark discharge has been created between the cathode and anode, preferably a transient voltage is applied between the cathode and anode, and current is passed through the cathode, plasma generating gas, and anode to produce a glow discharge. Result in the generation of. At the end of the glow discharge, when the cathode end is fully heated, the voltage between the cathode and anode drops, characterizing the beginning of cathode thermionic electron emission and the beginning of the arcing phase. When the arcing phase begins, plasma is deposited on all cathodes in the assembly. The current is reduced to reduce the plasma attachment area to a single cathode. Next, after the reduced current is maintained for a period of time, the current is increased to the operating level. After a predetermined pulse duration, both voltage and current are set to zero during the off period. This process is repeated for each pulse.

  For medical applications it is important that no impurities are present in the plasma. Sputtering from the surface of the cathode holder is reduced by utilizing a cathode assembly that includes a plurality of cathodes and generating a pulsed plasma having a region of controlled plasma attachment.

  During operation, the plasma flow exiting the anode has an essentially parabolic temperature and energy density distribution. The extension nozzle converts the temperature and energy distribution into a more uniform distribution that is more suitable for contact with the patient. The thermal insulator located in the extension channel is made of a non-metallic material with low thermal conductivity. As the plasma flows through this thermal insulator, the cooler plasma layer is heated without transferring heat to the elements forming the channel.

  Further, in embodiments having an inlet passage to the nozzle, the extension channel draws an oxygen carrying gas, such as air, into the flow while the plasma stream traverses the extension channel. Ozone is formed in the extension channel due to the high temperature of the plasma in the extension channel and the radiation emanating from the plasma channel. Ozone molecules that may have an advantageous effect escape the device together with the plasma and come into contact with the treated skin.

  In one embodiment, the anode extends longitudinally through the anode between the cathode and the anode, and (i) a cathode assembly including one or more cathodes and (ii) a cathode holder. A plasma channel having an exit opening at the anode end, wherein a portion of the plasma channel is electrically insulated from each other and formed by two or more intermediate electrodes electrically insulated from the anode; The plasma channel includes a heated portion closest to the cathode, an anode portion, and an enlarged portion between the heated portion and the anode portion, the enlarged portion having two or more sections that increase in diameter toward the anode. The minimum number of sections in the heated part depends on the ratio of the diameter of the plasma channel in the anode part to the diameter of the plasma channel in the heated part. A plasma channel formed by one of the intermediate electrodes and connected to the cathode end of the plasma channel; and an extension nozzle forming an extension channel connected to the anode end of the plasma channel; An apparatus for generating a pulse of plasma comprising is disclosed.

  Also, for each pulse, generating a plasma flow, expanding the plasma flow to a predetermined cross-section, and thermal energy of the expanded plasma flow so that the distribution is substantially uniform within the cross-section. Disclosed is a method of treating tissue using a pulse of plasma comprising the steps of: altering the distribution of the plasma, applying a plasma flow to the treatment skin, and stopping the plasma flow.

It is a figure which shows the pulse plasma production system provided with a console and a handpiece. It is a longitudinal cross-sectional view of embodiment of an apparatus. It is a longitudinal cross-sectional view orthogonal to the figure shown by FIG. 2A. 1 is a longitudinal cross-sectional view of an embodiment of an apparatus configured to generate ozone. It is a figure which shows a coolant distributor. It is a figure which shows the preferable structure of a cathode assembly. It is a figure which shows the geometric structure of a plasma chamber. FIG. 3 shows a heated portion, an enlarged portion, and an anode portion of a plasma channel and a section of the enlarged portion. 1 shows an embodiment of an apparatus comprising a suction module in which foreign objects are collected in a console. It is a figure which shows embodiment of an apparatus provided with the suction module by which a foreign material is collected by an external container. FIG. 6 is a cross-sectional view illustrating an embodiment of an apparatus comprising an extension nozzle including an oxygen carrying gas inlet and a suction module. FIG. 6 is a cross-sectional view illustrating an embodiment of an apparatus with an extended nozzle that does not include an oxygen carrying gas inlet and a suction module. It is a figure which shows the voltage applied between a cathode and an anode during the production | generation of a plasma pulse. FIG. 3 shows current passing through the cathode, plasma, and anode during the generation of a plasma pulse. It is a figure which shows the temperature profile of the plasma in the heating part of a plasma channel. It is a figure which shows the power density profile of the plasma in the heating part of a plasma channel. (1) Expansion of a plasma channel that does not cause complete expansion of the plasma during the pulse, and (2) an electric arc created between the plasma and the intermediate electrode. FIG. 3 shows a substantially parabolic temperature and power density distribution of a plasma stream exiting an anode. FIG. 10B illustrates the effect on tissue when treated with a plasma flow having the temperature and power density distribution shown in FIG. 10A. FIG. 5 shows a substantially uniform temperature and power density distribution of a plasma flow exiting an extension nozzle. FIG. 11B shows the effect on tissue when treated with a plasma flow having the temperature and power density distribution shown in FIG. 11A. FIG. 6 shows an extension nozzle having a relatively small diameter oxygen carrying gas inlet. It is a figure which shows the extension nozzle which does not have an oxygen carrying gas inlet. It is a figure which shows the spectral distribution of the light which leaves an apparatus.

  Referring to FIG. 1, the system for generating pulsed plasma roughly includes a console 100 and a handpiece 200. Handpiece 200 may be referred to herein as a device. The console 100 supplies the handpiece 200 with electricity, preferably a plasma generating gas that is argon, a coolant such as water, and / or an oxygen carrier gas such as air. In addition, the console 100 may include one or more pumps that may be used to remove foreign objects from the surface to be treated using the device 200 via one or more suction channels. The console 100 has a control circuit for operating the handpiece 200 and a user interface composed of a known display and control equipment. An operator, such as a trained medical professional, uses the console 100 controls to program the mode of operation of the device according to the parameters for a given medical procedure, and then performs the given procedure. The handpiece 200 is used for execution. Although the description of the embodiments of the present disclosure is related to the medical field, it will be understood that other embodiments of the device can be used for other applications not related to medicine.

  FIG. 2A shows a longitudinal section of one embodiment of the device. In this embodiment, the casing 9 forms the outside of the device. Preferably, the device 200 is cylindrical, all elements are annular and are arranged coaxially with respect to the axis 50 of the device. However, in some embodiments, the device may not be cylindrical and different internal or external geometries may be used. The device embodiment shown in FIG. 2A comprises an anode 1 and one or more cathodes 5 a, 5 b, 5 c, preferably made of tungsten containing lanthanum and arranged in a cathode holder 6. The cathode holder 6 prevents unwanted angular displacement of the cathode from the device shaft 50. The cathode holder 6 further holds a part of a conductor 7 which is preferably a metal rod with high conductivity. Caching together the components of the cathode assembly during manufacture is one means of preventing cathode displacement along axis 50. In a preferred embodiment, the entire cathode assembly constituted by the cathodes 5a, 5b, 5c, the cathode holder 6 and the conductors 7 prevents any movement of the cathodes 5a, 5b, 5c, so Is closely fitted.

  The cathode insulator 11 surrounds the longitudinal part of the cathodes 5a, 5b, 5c. The cathode insulator 11 extends from the surface 74 of the cathode holder closest to the anode at one end to an intermediate point along the cathode. The cathode insulator 11 is made of a material that provides both thermal and electrical insulation of the cathodes 5a, 5b, 5c. The conductor 7 is used to supply a potential to the cathodes 5a, 5b, and 5c. The cathodes 5a, 5b, 5c are electrically connected and always have the same potential. Insulator element 8 surrounds conductor 7 and a portion of cathode holder 6 as shown in FIG. 2A. Insulator element 8 electrically insulates conductor 7, and is preferably made of vinyl. During operation, the passage 72 allows the flow of plasma generating gas from the console 100 along the insulator 8. The gas then flows along the space 54 between the insulator 8 and the water divider 10. Thereafter, the gas flows in the groove 56 of the cathode holder 6 and then flows inside the cathode insulator 11 along the cathodes 5a, 5b, and 5c.

  In a preferred embodiment, the cathode assembly may be that shown in FIG. Briefly, the cathode assembly comprises two or more cathodes. In the preferred embodiment shown in FIG. 4, the cathode assembly comprises three cathodes 5a, 5b, 5c. Preferably, the diameter of each cathode is 0.5 mm. In a preferred embodiment, the combined diameter of the three cathodes is about 1 mm. At least one cathode has a different length compared to the other cathodes of the cathode assembly. Also preferably, each cathode has a different length than all of the other cathodes in the assembly. The difference in length between the two cathodes with the closest length is preferably comparable to the cathode diameter, and in a preferred embodiment is 0.5 mm. The difference in length between the cathodes creates a natural surface imperfection where the electric arc tends to adhere.

  In alternative embodiments, a cathode assembly that includes a single cathode may be used, but such embodiments are limited to applications that require only a limited number of pulses. The cleaning of the substrate surface with plasma pulses in microchip manufacture is such an application. An embodiment of a device with a cathode assembly that includes a single cathode is suitable for generating at most 300 to 500 pulses. After about 500 pulses, the temperature of the entire cathode body rises. This causes an enlargement of the contact area between the plasma and the cathode surface when the arc is initiated. As a result, the plasma contacts the cathode holder. As the cathode holder begins to melt, the plasma damages the cathode where the cathode and cathode holder are connected, creating an imperfection at that location of the cathode. When an imperfection is created, the electric arc tends to adhere to the imperfection of the cathode rather than to the tip of the cathode, interfering with the normal process of pulsed plasma generation and causing device instability. After the device has cooled to room temperature, another 300-500 pulse train can be generated. Thus, this alternative embodiment may be used for applications that require a limited number of pulses not exceeding about 500. The maximum number of pulses may be increased by increasing the cathode length by moving the end of the cathode closest to the anode away from the cathode holder, but only slightly.

  Alternatively, to solve the problem of operational instability after hundreds of pulses in the embodiment of the apparatus using a single cathode, the cathode is “trained” in continuous plasma mode before switching to pulsed plasma. Can also be done. Cathode training refers to the operation of the device in a continuous plasma mode in which high DC current is passed through the cathode. Initially, due to the cathode geometry and, in some embodiments, the plasma chamber geometry, an electric arc attaches to the tip of the cathode, and DC current is applied to the cathode for a sufficiently long time. Pass through the tip and create an imperfect surface at the very tip of the cathode. When the device is switched to pulsed plasma mode after the cathode has been “trained”, the electric arc adheres to imperfections in the cathode tip created by “training”.

  During operation, plasma generated gas flows from the console 100 to the apparatus 200. Plasma generated gas enters the apparatus via passage 72. The plasma generating gas passes through the cathode insulator 11 and then passes through the plasma channel 62. This direction is called the plasma flow direction. In embodiments comprising a plasma chamber, the plasma generating gas passes through the plasma chamber 26 before entering the plasma channel 62. The plasma channel 62 is formed by the anode 1 and two or more intermediate electrodes. The end of the plasma channel farthest from the cathode is called the anode end of the plasma channel, and similarly the end of the plasma channel farthest from the anode is called the cathode end of the plasma channel. The plasma channel 62 has an outlet at the anode end. In the embodiment shown in FIG. 2A, the plasma channel 62 is formed by the anode 1 and the intermediate electrodes 2, 3 and 4. The intermediate electrode 4 further forms a plasma chamber 26. In other embodiments, the electrodes forming the plasma chamber 26 do not form part of the plasma channel 62. Insulators 14, 13 and 12 provide electrical insulation between adjacent pairs of electrodes. The insulator 14 performs electrical insulation between the anode 1 and the intermediate electrode 2, the insulator 13 performs electrical insulation between the intermediate electrodes 2 and 3, and the insulator 12 is coupled between the intermediate electrodes 3 and 4. Perform electrical insulation. The principle of plasma generation using a multi-electrode system is well known.

  FIG. 2B shows a longitudinal section orthogonal to the section shown in FIG. 2A of the embodiment of the apparatus 200 shown in FIG. FIG. 2B shows a cooling system that includes an inlet 76, a forward coolant channel 78, a circulating coolant channel 42 (shown in FIG. 2A), a reverse coolant channel 79, and an outlet 77. A coolant, preferably water, enters the device through inlet 76. The coolant then traverses forward coolant channel 78 along plasma channel 62 in the direction of plasma flow from cathode 5a, 5b, 5c to anode 1. In the region of the anode 1, the forward coolant channel 78 leads to the circulation channel 42 shown in FIG. 2A. The coolant flows along the circulation channel 42 around the anode 1. On the diametrically opposite side of the device, the circulation channel 42 leads to a reverse coolant channel 79. The coolant flows from the anode 1 to the cathodes 5a, 5b, 5c along the reverse coolant channel 79 in the opposite direction to the plasma flow and then exits the device through the outlet 77.

  FIG. 3 shows the coolant distributor 10 that forms the forward coolant channel 78, the circulation channel 42, and the reverse coolant channel 79 together with the other elements. Some embodiments of the apparatus may comprise multiple cooling systems. Such embodiments further comprise a plurality of coolant distributors that form respective channels of other cooling systems.

  A plasma chamber may be used if the device 200 is subject to size restrictions such as for keyhole surgery. FIG. 5 shows the plasma chamber 26 in greater detail. The geometry of the plasma chamber 26 is important for proper functioning of the device. The cathodes 5a, 5b, 5c tend to emit electrons from imperfections in the surface of the cathode, for example from the corresponding edges 68a, 68b, 68c of the cathode. For proper operation, at the beginning of each pulse, a spark discharge should be created between one of the cathode edges 68a, 68b, 68c and a point on the inner surface of the plasma channel 62. In order to achieve this, the following conditions should be met: The distance between the cathode edges 68a, 68b, 68c and the point on the inner surface of the plasma channel, eg, point 64, is the cathode insulation closest to the cathode edges 68a, 68b, 68c, the inner surface of the plasma chamber 26, and the anode. It must be less than or equal to the distance between other surfaces that the electrical spark may terminate, such as the body edge 66. If the geometry of the plasma chamber 26 and the cathodes 5a, 5b, 5c shown in FIG. 5 are used, during the start-up of the device, electrical sparks are generated on the cathode 5a, 5b, 5c and the inner surface of the plasma channel 62. It occurs between a point, for example, point 64. This ensures proper operation of the plasma generation process. This geometry of the plasma chamber 26 may provide other advantages, such as reducing the time required to achieve the arcing phase that is important for the pulsed plasma, as described below. As with most skin treatment applications, if the device 200 is not subject to size restrictions, the plasma chamber may not be present.

  FIG. 6 shows the structure of the plasma channel 62. The plasma channel 62 includes a heating portion 84, an enlarged portion 82, and an anode portion 83. The enlarged portion 82 and the anode portion 83 are used to expand the plasma flow to the cross-sectional area required for a given application. The enlarged portion 82 includes one or more enlarged sections. In the embodiment shown in FIG. 6, the enlarged portion 82 includes enlarged sections 86, 88 and 90.

In the preferred embodiment, the heated portion 84 is formed by two to five intermediate electrodes. In alternative embodiments, the heating portion 84 may be formed by a single intermediate electrode or six or more intermediate electrodes. The diameter d _hp of the heating part 84 is preferably in the range of 0.5 to 1.5 mm. The length l _{e_hp} of each electrode forming the heated portion 84 depends on d _hp and preferably falls within the range of d _hp to 2 × d _hp . The overall length of the heating portion depends on the flow rate of the plasma generating gas, and a longer heating portion is required to heat a larger plasma generating gas stream. For typical flow rates of plasma generated gas falling in the range of 1 to 2 liters per minute, the heated portion is formed by at least three intermediate electrodes. The total length l _hp of the heating part may be approximated by multiplying the number of intermediate electrodes required to form the heating part by the length l _{e_hp} of such intermediate electrode.

  The number of sections in the enlarged portion 82 depends on the diameter of the heating portion 84 and the diameter of the anode portion 83 and is defined by the following relationship.

N _s ≧ (d _A −d _hp ) / c−1

Where N _s is the number of sections in the enlarged portion of the plasma channel.

d _A is the diameter of the anode portion of the plasma channel in millimeters.

d _hp is the diameter of the heated portion of the plasma channel in millimeters.

  For this and other formulas, c is a constant that falls between 0.2 and 0.6 mm, preferably 0.4 mm. As will be described later, c may be selected to be less than 0.2, but such selection of the value of c results in an impractical length of device 200.

  For purposes of this disclosure, the sections of the enlarged portion 82 are counted from the cathodes 5a, 5b, 5c toward the anode 1. Thus, section 86 is the first section, section 88 is the second section, section 90 is the third section, and so on. If a particular embodiment has more than three sections, these sections are similarly counted in this way. The section dimensions of the enlarged portion 82 are preferably defined by the relationship:

d _n is preferably d _n-1 + c.

l _n is preferably between d _n and 2 × d _n .

  Where n is the section number of a given section.

d _n is the diameter of the n-th section.

l _n is the length of the nth section.

To determine the diameter of section 86 of FIG. 5, which is section number 1, the value of d ₀ required to calculate d ₁ is set to the heated portion diameter d _hp .

  The diameter of the anode portion 83 is preferably defined by the following relationship.

d _A is preferably d _z + c.

l _A is preferably between 2 × d _A and 5 × d _A.

Here, d _A is the diameter of the anode portion.

l _A is the length of the anode part.

  z is the number of the enlarged section of the enlarged portion 82 closest to the anode. In FIG. 6, z is 3 that is the number of the enlarged portion 90.

  In a preferred embodiment, the cross section of the plasma channel perpendicular to the longitudinal direction of the plasma channel is circular. However, in other embodiments, the cross-section may have a different geometry.

  In some embodiments of the device, each section of the enlarged portion is formed by a separate intermediate electrode. In other embodiments of the device, one intermediate electrode may form part of two or more adjacent sections. In still some other embodiments, the plurality of intermediate electrodes may form part of one section of the enlarged portion, or the entire section, and the other plurality of intermediate electrodes may be two or more adjacent Only part of the section may be formed. In the embodiment shown in FIG. 2A, intermediate electrode 3 forms section 86 (and heated portion 84), and intermediate electrode 2 forms sections 88 and 90.

  Device 200 includes an extension nozzle. For example, returning to FIG. 2A, the extension nozzle 15 is attached to the anode end of the device. The extension nozzle 15 has an extension channel 18 that extends the plasma channel. A part of the extension channel 18 is formed by a tubular insulator element 17 made of ceramic material or quartz. The tubular insulator element 17 prevents the discharge from terminating in the extension nozzle 15. That prevents electrode material from separating from the extension nozzle 15 and entering the plasma stream during operation of the apparatus 200. This ensures the purity of the plasma exiting the extension channel from the outlet 55. The diameter of the portion of the extension channel 18 formed by the tubular insulator element 17 preferably falls within the range of 1.0 to 1.3 times the diameter of the anode portion 83 of the plasma channel 62. The length of the extension channel 18 is preferably 2 to 3 times the diameter of the extension channel. In these embodiments configured for ozone generation, the extension nozzle 15 further has one or more oxygen carrying gas inlets 16 as shown in FIG. 2C. The inlet 16 is used to supply an oxygen carrying gas, preferably air, to the extension channel 18 that can be used for the production of ozone, as described below.

The calculation of the dimensions of the different elements in a preferred embodiment of the device is illustrated by the following embodiment. The heated portion has a diameter of 1.0 mm and a length of 1.5 mm (mainly dependent on the flow rate of the plasma generating gas), and the desired diameter of the plasma stream exiting the device from the outlet 55 of the extension channel is 4. Assume 8 mm. The extension channel diameter is 4.8 mm, and the length of the extension channel can be set to a length that falls within the range of 2 to 3 times the diameter of the extension channel, for example, 14.0 mm. The diameter of the extension channel should be 1.0 to 1.3 times the diameter of the anode portion of the plasma channel, preferably 6 mm to 12 mm. In this embodiment, if the diameter of the extension channel is 1.2 times the diameter of the anode portion of the plasma channel, the diameter of the anode is 4.0 mm. The length of the anode portion may be any length between 2 times the diameter of the anode portion and 5 times the diameter of the anode portion. In this embodiment, when the length of the anode is set to 3 times the diameter of the anode, the length is 12.0 mm. The enlarged portion expands the diameter of the plasma channel from the diameter of the heated portion 84 which is 1.0 mm in this embodiment to the diameter of the anode portion of the plasma channel which is 4.0 mm. Therefore, in the present embodiment, the enlarged portion enlarges the diameter of the plasma channel by 3.0 mm. This expansion can be achieved in a number of ways. For example, the diameter of each section of the enlarged portion can be increased by a maximum value c of 0.6 mm. In this case, the number N _s of sections within the enlarged portion is 4. The diameters of these sections are 1.6 mm, 2.2 mm, 2.8 mm and 3.4 mm. The length of the section may be set to any value between 1 and 2 times the diameter. Thus, the section lengths may be 2.0 mm, 3.0 mm, 4.0 mm, and 5.0 mm, respectively. If the diameter increase of each section is selected to be less than 0.6 mm, more sections are required in the enlarged portion.

Alternatively, c may be set to the preferred value of 0.4 mm. In this case, the number N _s of section of the enlarged portion is 7. The diameters of these sections are 1.4 mm, 1.8 mm, 2.2 mm, 2.6 mm, 3.0 mm, 3.4 mm and 3.8 mm. Section lengths can be 3.5 mm, 4.5 mm, 5.5 mm, 6.5 mm, 7.5 mm, 8.5 mm and 9.5 mm, respectively. It should be noted that in this embodiment, the expansion between the enlarged section closest to the anode and the anode is only 0.2 mm, not 0.4 mm. This expansion does not impair the functionality of the device.

  It is further possible to have different enlargements between different pairs of sections of the enlarged portion. For example, the expansion from the heated portion to the first section may be 0.4 mm, and the expansion between the other expansion sections and the anode may be 0.5 mm.

  The above description assumes that the intermediate electrode, the anode, and the extension nozzle are annular, so that the portions and sections of the plasma channel and the extension channel are cylindrical. As described above, in some embodiments, other device geometries may be used. In these embodiments, for the purposes of this disclosure, the diameter of the cross section perpendicular to the longitudinal direction of the plasma channel, which is the largest distance between two points of the shape, is still an important dimension for the purposes of the above calculations. .

  As described above, when the plasma is used to perform a medical procedure, foreign objects may be created that may weaken the effect of the plasma. For example, during a medical procedure, particles or fragments may separate from the treatment tissue and then interfere with the plasma flow to the target site of the treatment tissue, or in some cases interfere with the plasma flow. Similarly, during certain medical procedures, body fluids such as blood and lymph may enter the surface of the treatment site. These fluids can interfere with the effectiveness of the plasma. Some embodiments of the device include a suction module that removes such foreign objects from the treatment surface during a medical procedure. FIG. 7A shows an embodiment of the device with a suction module. In this embodiment, the outer casing 92 encloses the device shown in FIGS. 2A-C. The outer casing 92 has one or more suction channels 94, 96. A pump operating inside the console 100 draws foreign objects from the treated tissue. The foreign material flows along channels 94 and 96 and then to the console 100, where the foreign material is accumulated in a collection unit (not shown in FIG. 7A). FIG. 7B shows a different embodiment of an apparatus including a suction module. This embodiment is similar to the embodiment shown in FIG. 7A, except that the channels 94 and 96 do not extend along the length of a portion of the device and are connected to the outlet 98. . In embodiments that include both a suction module and an extended nozzle with an oxygen carrying gas inlet, the inlet passes through the casing 92 as shown in FIG. 7C showing section AA in FIG. 7A. Note that it extends. FIG. 7D shows a cross section AA in an embodiment with an extended nozzle that does not include an oxygen carrying gas inlet.

  In a preferred embodiment, the device produces a truly pulsed plasma. After each plasma pulse, during the off period, the plasma flow stops completely until the next pulse. Between pulses, during the off period, no current flows between the cathode and anode and no plasma is generated.

  The console 100 has one or more electronic circuits that control the current passing through the plasma channel and apply a voltage between the cathode and the anode. These circuits are used for the generation of each plasma pulse. In summary, the plasma generation process includes three stages: spark discharge, glow discharge, and arc discharge. During the arcing phase, a predetermined current electric arc created between one of the cathodes and the anode heats the plasma generating gas flowing in the plasma channel 62 to form a plasma. The generation of each plasma pulse requires the plasma generating gas to go through all stages. Before the generation of the pulse, the resistance of the plasma generating gas is nearly infinite. A small number of free electrons are present in the plasma product gas due to the ionization of atoms by cosmic rays. The plasma formation process consists of (1) applying a voltage applied between the cathode and anode as shown in FIG. 8A, and (2) current passing through the plasma as shown in FIG. 8B. It is controlled by controlling.

  The method of operating the device depends on the structure of the cathode assembly and may vary depending on the configuration of the device and the particular application in which the device is used. In a preferred embodiment of the apparatus having a cathode assembly comprising a plurality of cathodes, a method of operation that is particularly adapted for the cathode assembly shown in FIG. 4 is used. Briefly, a high amplitude, high frequency voltage wave is applied between the anode 1 and the cathodes 5a, 5b, 5c to create a spark discharge. This voltage wave increases the number of free electrons in the plasma channel 62 between the cathodes 5a, 5b, 5c and the anode 1. The frequency, duration, and amplitude of the voltage wave depend on the device geometry. When a sufficient number of free electrons are formed, a DC voltage is applied between the anode 1 and the cathodes 5a, 5b, 5c, and a DC current is passed through the cathode, plasma generating gas, and anode, Spark discharge is formed between the cathodes 5a, 5b and 5c and the anode 1.

  Thereafter, the resistance of the plasma generating gas decreases and the glow discharge phase begins. During the glow discharge phase, positively charged ions formed as a result of ionization are attracted to the cathode under the influence of the electric field created by the voltage between the cathodes 5a, 5b, 5c and the anode 1. When ions collide with the cathodes 5a, 5b, and 5c, the temperature at the cathode end closest to the anode 1 rises. When the temperature rises to the temperature of thermionic electron emission, the arc discharge phase begins. As described above, the surface area and volume of the plasma chamber 26 supplies a large number of ions, shortening the duration of the glow discharge phase.

  When arcing begins, the plasma adheres to all cathodes in the assembly. The current through the plasma then decreases, reducing the area of the attachment that can sustain the arc discharge to a nearly minimal area. This minimum area is called a spot attachment area. Because the area of the plasma attachment is small, the attachment appears only on a single cathode. Therefore, the current required to maintain arc discharge and proportional to the cathode diameter is relatively low. After the current is lowered and held at that level for a period of time, the current is rapidly increased to the operating level of the pulse. The area of plasma attachment increases slightly and only a single cathode continues to emit electrons during the remainder of the pulse. It is critical to the operation of the device to reduce the area of the plasma attachment and then maintain a small area so that only a single cathode emits electrons from the controlled area.

  As described above, different embodiments may use variations of this method of operation. For example, in alternative embodiments using a single cathode, the region of attachment may only be controlled using cathode length and cathode end tapering or cathode training. In these embodiments, the current is increased to an operational level as soon as the arcing phase is reached.

  The geometry of the elements of the disclosed embodiment and the shape and synchronization of the voltage and current pulses can be achieved with multiple cathodes (or depending on the embodiment) when there is not enough thermionic electron emission to support the current. Ensuring that one cathode) is not affected by high current stresses flowing through the cathode. This, in other words, ensures that the device can be activated thousands or even tens of thousands of times using the same cathode assembly.

  The relationship between the dimensions of the different sections in the enlarged portion allows the plasma to expand rapidly during the operation of the pulse. This is important for generating a pulse of plasma with the required characteristics. Experimentally, a per-time increase in plasma channel diameter above 0.6 mm may result in incomplete plasma flow expansion during pulse operation, or in some cases no expansion at all. all right. In other words, if the diameter of the nth section of the enlarged portion is increased by more than 0.6 mm compared to the diameter of the (n-1) th section, the plasma flow will expand to the diameter of the nth section. Without plasma flow, the plasma flow is limited to a specific cross section that is smaller than the cross section of the nth section while traversing the remaining downstream portion of the plasma channel and the extension channel. FIG. 9 illustrates this idea. In FIG. 9, the enlarged portion 82 does not exist. The heating portion 84a moves to the anode portion 83a. The diameter of the anode part 83a exceeds the diameter of the heating part 84a by more than 0.6 mm. The plasma flowing through the plasma channel 62a does not expand or expands sufficiently during the operation of the pulse when the plasma enters the anode portion 83a. A very similar situation occurs when there is an enlarged portion but the difference in diameter between adjacent sections exceeds 0.6 mm. However, when the size of the enlarged portion falls within the range determined by the above relationship, the plasma flow expands to the entire cross-section of the anode end of each section, so that the plasma flow diameter is the diameter of the extension channel at the outlet 55 be equivalent to. Note that for longer pulse or continuous plasma flows, an increase of 0.6 mm or more results in a partially expanded plasma flow. In essence, for short pulses required for applications such as skin treatment, the increase in diameter per stroke is such that the plasma flow fully expands to an increased diameter in each section. It must be 6 mm or less.

  Another problem that emerges with a single diameter increase exceeding 0.6 mm is the possibility of an electric arc formed between the plasma flow and the anode wall if the plasma flow is separated from the wall. This is also shown in FIG. FIG. 9 shows an electric arc 171 formed between the plasma flow and the wall of the anode 1. Such an electric arc takes the electrode material into the plasma flow and mixes impurities into the plasma. This process of gradually expanding the plasma flow plays a major role in producing a truly pulsed plasma flow when the current in the arc increases rapidly and at the same time the plasma in the flow is not sufficiently heated. Fulfill.

  Enlarging the diameter of the plasma channel to less than 0.2 mm does not result in impurities or inadequate plasma expansion. However, an enlargement of less than 0.2 mm is also undesirable. In particular, an enlarged device of less than 0.2 mm will require a larger number of enlarged sections. Since each expansion section has a minimum length requirement for the expansion section, having a larger number of expansion sections means that the device is longer and inconvenient. Furthermore, apart from simply being inconvenient, the increase in the number of expansion sections means that more energy is needed to heat the plasma flow across the plasma channel whose length has been increased due to the increase in the number of expansion sections. Therefore, it requires more power. Thus, the device will function properly even when the section diameter is increased by less than 0.2 mm, but each expansion is preferably in the range of 0.2 to 0.6 mm.

As the plasma expands in the enlarged portion 82, some of the characteristics of the plasma change. During the operating period of the pulse, the heated portion is characterized by a power density in the range of 0.3 to 5 kW / mm ³ as shown in FIG. 8D. The average velocity of the plasma flow in the heated part is preferably 500 m / s or less. The average temperature of the plasma is 8000 to 18000K, preferably 10,000 to 16000K as shown in FIG. 8C. The electric field in the heated part is preferably in the range of 2 to 25 V / mm.

The magnified portion is characterized by a power density of less than 0.3 kW / mm ³ . The average temperature of the plasma in the enlarged portion preferably remains in the range of 8000-18000K. The electric field in the enlarged part of the plasma channel is preferably in the range of 1 to 5 V / mm.

  After the plasma stream expands in the enlarged portion 82 of the plasma channel, the plasma stream reaches the extension nozzle 15. The extension nozzle 15 has two effects on the plasma flow, i.e., first, the extension nozzle changes the temperature and energy distribution of the plasma flow to make it suitable for specific applications such as tissue treatment. Second, the extension nozzle can create ozone and nitric oxide in the plasma stream.

  The first effect of the extension nozzle 15 on the plasma flow is to change the temperature and energy distribution of the plasma flow. During the arc discharge phase, an electric arc between the cathode and anode heats the plasma in the plasma channel 62. Only a small part of the plasma forms the center of the plasma stream, which is hot. The remaining plasma has a substantially lower temperature because it flows along the periphery of the plasma channel away from the electric arc. Since the intermediate electrode and the anode forming the plasma channel are made of metal having a high thermal conductivity, the plasma flowing along the outer periphery of the plasma channel cannot be heated to the same temperature as the plasma flowing through the center. Therefore, the heat transferred from the plasma flowing in the center to the plasma flowing along the outer periphery is transferred to the intermediate electrode and the anode, and is not maintained by the plasma flowing along the outer periphery. When the plasma reaches the anode end of the plasma channel 62, the plasma has a substantially parabolic temperature distribution as shown in FIG. 10A. As shown in FIG. 10A, the temperature of the plasma at the center of the plasma flow is substantially higher than the temperature around the plasma flow. Similarly, the plasma energy density proportional to temperature is substantially higher at the center of the plasma flow than at the periphery.

  Such plasma flow temperature and energy density distributions are not suitable for some applications such as skin treatment. When a plasma flow pulse with such a temperature and energy density distribution contacts the patient's skin, a small area of the skin absorbs most of the energy of the plasma flow pulse, and a much larger area is the rest of the energy. To absorb. FIG. 10B shows a circular area 190 of the skin having the diameter of the plasma channel at the anode portion. If a pulse of plasma flow is in contact with region 190 as shown in FIG. 10A, about 20% portion 192 of region 190 absorbs about 80% of the energy stored in the plasma pulse. The remaining 80% portion 194 of region 190 absorbs only about 20% of the energy stored in the plasma pulse.

The extension nozzle changes the temperature and energy density distribution to a substantially uniform distribution as shown in FIG. 11A. In other words, the temperature and energy density of the plasma flow exiting the extension nozzle from the outlet 55 is approximately the same as the temperature and energy density in the entire cross section of the flow. FIG. 11B shows an area of skin that has been treated using a plasma stream having the distribution shown in FIG. 11A. As shown in FIG. 11B, when a pulse of plasma flow contacts the skin, the entire region is substantially uniformly affected by the pulse and accepts substantially more energy or substantially less energy. There is no spot. In a preferred embodiment, the geometry of the elements in the device is such that the energy density of the plasma applied to the treated tissue is between 5 and 500 J / cm ² as well as the operating parameters (ie plasma generated gas flow rate, current magnitude, etc.) Is selected to be In other embodiments, other energy densities may be realized.

  As described above, when the plasma exits the anode and enters the extension channel, the temperature and energy density of the plasma has a parabolic distribution as shown in FIG. 10A. One of the main reasons why the plasma flow does not achieve a uniform temperature in the plasma channel is that the intermediate electrode and anode are made of a metal with high thermal conductivity, such as copper. is there. Due to the high thermal conductivity, heat from the plasma is transferred to the coolant flowing along channels 78 and 79. Since the anode 1 and the intermediate electrode cool the periphery of the plasma intensively, a large temperature gradient is formed. The insulator element 17 located in the extension channel 18 is preferably made of a quartz or ceramic material having a very low thermal conductivity. Thus, when the heated plasma contacts the insulator element 17 that does not cool the plasma, heat is not distributed throughout the volume of the insulator element 17. Only the inner surface of the insulator element 17 in contact with the heated plasma is rapidly heated to the temperature of the plasma and not cooled. Since there is minimal heat dissipation to the extension nozzle, the temperature of the plasma flowing along the outer periphery will rise. Since heat is transferred from the center of the flow to the periphery, heat is not transferred to the structural elements of the device. Furthermore, in the extension channel 18, the center of the plasma flow is not heated by an electric arc terminating at the anode. Thus, when the plasma flow exits the extension channel outlet 55, the plasma flow has a substantially uniform temperature and energy density distribution, as shown in FIG. 11A. FIG. 11B illustrates that a substantially uniform temperature and energy density distribution produces a substantially uniform effect on the treated tissue by the plasma.

The second incidental effect of the extension nozzle is to produce ozone and nitric oxide. In some countries, ozone has been approved to exhibit useful properties in medicine, such as antibacterial activity. In other countries, however, the usefulness of ozone has not been approved. However, it is a well-known technique that ozone is formed from oxygen by discharge, high temperature, high energy electromagnetic radiation irradiation. When O ₂ molecules are incorporated into the plasma flow, some of the molecules are dissociated into oxygen atoms under the influence of one or more of the above conditions, and then recombined with the O ₂ molecules to ozone ( O ₃ ).

  In some embodiments, the device produces ozone, and in other embodiments, the device does not produce ozone. Ozone generation can be controlled in two ways. First, oxygen carrier gas injection is controlled by reducing the diameter of the inlet or, in some cases, completely removing the oxygen carrier gas inlet. FIG. 12A shows an extension nozzle 15 that includes a relatively small diameter inlet 16. FIG. 12B shows the extension nozzle 15 having no oxygen carrying inlet. Second, the length of the extension channel 18 can be shortened so that the oxygen entering from the inlet does not have enough time to undergo the reaction required to produce ozone. is there. It is understood that by using one or both of these methods of controlling ozone production, the amount of ozone produced by the apparatus 200 can be increased, decreased, or even eliminated altogether. Should. Nitric oxide production is similarly controlled. The following description relating to the production of ozone and nitric oxide assumes that the extension nozzle 15 has one or more oxygen and nitrogen carrying gas inlets 16.

Referring to the process that results in the production of ozone, the plasma stream enters the extension nozzle 15 after traversing the plasma channel. The temperature of the plasma stream in the extension channel is preferably reduced to 3000-12000K. During operation, as the plasma passes through the oxygen carrying gas inlets 16, the plasma creates an aspiration effect at these inlets 16 that draws an oxygen carrying gas, such as air, into the extension channel 18. Within the extension channel, a portion of the air preferably falls in the range of 5 to 25% by volume. It is well known that air contains about 21% by volume O ₂ oxygen, and therefore a portion of O ₂ in the extension channel preferably falls in the range of 1 to 5% by volume. Some oxygen molecules dissociate into atoms and then recombine with O ₂ oxygen molecules and sometimes recombine with other dissociated oxygen atoms, resulting in two factors: (1) relatively high energy. Ozone is formed under the influence of the collision of O ₂ molecules with the electrons it has and (2) the ultraviolet rays from the plasma channel resulting from the emission of plasma-generated gas molecules, electrons and other particles. Ozone molecules are formed according to the following chemical reaction.

e + O ₂ → O + O ⁻

e + O ₂ → O + O + e

O + O ₂ + M → O ₃ + M

  Here, M may be any reactive particle such as a rare gas, for example, argon.

  Another effect of incorporating oxygen and nitrogen carrying gases into the plasma stream is nitric oxide (NO) production in the extension channel 18. Various therapeutic effects of NO and methods for generating NO are well known and approved in several countries. For example, US Pat. No. 5,396,882 discloses a system and method for generating NO by entraining air into an electric arc chamber. The embodiment of the device with the expansion module similarly creates conditions for generating NO. Incorporation of nitrogen and oxygen carrying gases such as air into the plasma stream creates the optimum conditions for synthesis of NO in the expansion channel 18. As described above, the temperature of the plasma at the anode outlet falls within the range of 3000-12000K. This temperature is high enough to cause the following chemical reaction in a plasma stream with air molecules, in parallel with ozone generation.

N ₂ + O ₂ → 2NO-180.9kJ

  In some embodiments, air, oxygen ratio, or both may be varied. For example, in some embodiments, oxygen enriched air may be supplied to the oxygen carrying gas inlet 16. In other embodiments, the air supplied to the oxygen carrying gas inlet 16 may be pressurized, thus making the concentration of air in the plasma higher. In still some other embodiments, a combination of the two above methods may be used.

  In addition to outputting the plasma and, in some embodiments, outputting ozone and nitric oxide, the device emits light due to radiation from the hot plasma in the heated portion of the plasma channel. There is also. For example, in US Patent Application Publication No. 2003004556, there are various types of pulsed light having a dominant emission wavelength of about 300 nm to about 1600 nm and whose pulse duration varies from 1 femtosecond to 100 seconds. Have been discovered and disclosed. In particular, the treatment of hair, epidermis, superficial blood vessels, and many other organs has shown that it is advantageous to use such pulsed light. U.S. Patent Application Publication No. 2003004556 discloses various devices and methods for generating pulsed light having the required characteristics.

  As mentioned above, the temperature of the plasma in the heated part is preferably between 8000 and 18000K. In this temperature range, the plasma stream emits light having a dominant emission wavelength from about 400 nm to about 850 nm. FIG. 13 shows a spectral distribution 302 of light at a distance of about 3 mm from the outlet 55 and a spectral distribution 304 of light at a distance of about 50 mm from the outlet 55. FIG. 13 shows the following spectral distribution.

  200-350nm 2%

  350-400nm 5%

  400-650nm 62%

  650-750nm 15%

  750-850nm 14%

  850-1400nm 2%

  Thus, the device 200 may be used for pulsed light therapy in conjunction with other applications. It should be noted that the ratio of the short and long wavelengths of the emitted light spectrum may be easily changed by adjusting the magnitude of the current passing through the plasma stream during the operation of the pulse. With increasing current, approximately the same amount of energy is used for plasma generation, but substantially more energy is used for light emission.

  With respect to patient treatment, the device can be used safely and effectively without having to separate the device from the treated tissue after each pulse, as had been the case with some prior art devices. Can. Thus, plasma pulses can be automatically generated at a relatively high frequency. For each pulse, a new plasma stream is generated by first passing through the spark discharge phase and the glow discharge phase, and then heating the plasma generating gas using an electric arc during the arc discharge phase. Once the plasma stream is created, the plasma stream is expanded in the plasma channel by passing through a section of the enlarged portion, then through the anode portion, and then through the extension channel. Within the extension channel, the heat and energy density distribution of the plasma stream is altered to be substantially uniform across the cross section of the extension channel, as described above. The expanded plasma stream with the altered thermal energy distribution is safely applied to the patient's skin for the duration of the pulse. At the end of the pulse, the plasma flow stops completely. This process can be repeated until the desired number of pulses has been delivered. The generated light radiation provides benefits for the treatment of skin and superficial organs such as dermis and blood vessels in addition to the benefits arising from plasma pulses.

  Foreign bodies are removed from the surface of the treated skin. The removal of the foreign material does not need to be synchronized with the pulse, and may be performed continuously. In addition, ozone may be mixed into a plasma stream that is applied to the patient's skin for additional beneficial effects. As mentioned above, incorporating oxygen carrying gas into the extension inlet results in the formation of ozone molecules in the plasma stream.

  Importantly, after a pulse of plasma is applied to the skin, the plasma flow stops completely until the next pulse. During the off period, no plasma is applied to the patient's skin, and the patient is only exposed to a harmless cold plasma-generating gas flow and a vacuum pump vacuum. Thus, the operator using the device does not run the risk of error by attempting to move the device away from the patient's skin during the off period and then reposition the device correctly to continue treatment. This substantially improves the safety and duration of treatment.

  The foregoing descriptions of embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiments have been selected and described in order to best explain the principles of the invention and the practical application of the invention, thereby enabling those skilled in the art to understand the invention. Various embodiments and modifications suitable for a particular use are contemplated. It is intended that the scope of the invention be defined by the appended claims and their equivalents.

Claims (21)

An apparatus for generating a pulse of plasma,
a. An anode,
b. A cathode assembly including (i) one or more cathodes, and (ii) a cathode holder;
c. A plasma channel extending longitudinally through the anode between the cathode assembly and the anode and having an outlet opening at an anode end, wherein portions of the plasma channels are electrically connected to each other; Formed by two or more intermediate electrodes that are insulated and electrically insulated from the anode, the plasma channel comprising a heating portion closest to the cathode assembly, an anode portion, the heating portion and the heating portion A plasma channel including an enlarged portion between the anode portion, the enlarged portion having two or more sections, wherein the diameter of each successive section of the enlarged portion increases toward the anode;
d. An extension nozzle connected to the anode end of the plasma channel and forming an extension channel having a tubular insulator covering a portion of the inner surface;
A device comprising:   The apparatus of claim 1, further comprising a plasma chamber.   The apparatus of claim 1, wherein the cathode assembly includes two or more cathodes.   The section of the enlarged portion has a diameter that is (i) 0.6 mm or less larger than the diameter of a section adjacent in the direction of the cathode assembly; and (ii) has a length that is greater than or equal to the diameter of the section of the enlarged portion. The apparatus of claim 1.   The section of the enlarged portion that is closest to the cathode assembly has a diameter that is (i) 0.6 mm or less larger than the diameter of the heated portion, and (ii) has a length that is greater than or equal to the diameter of the section of the enlarged portion. 5. The apparatus of claim 4, comprising: a. The diameter of the heated portion is 1.0 to 1.5 mm;
b. The length of the electrode forming the heating part is 1.0 to 2.0 times the diameter of the heating part,
The apparatus according to claim 5. a. The diameter of the anode portion is 0.6 mm or less larger than the diameter of the section of the enlarged portion closest to the anode,
b. The length of the anode portion is 2.0 to 5.0 times the diameter of the anode portion;
The apparatus according to claim 6. i. The inner diameter of the tubular insulator element is 1.0 to 1.3 times the diameter of the anode portion;
ii. The length of the extension channel is 2.0 to 3.0 times the inner diameter of the tubular insulator;
The apparatus according to claim 7.   The apparatus of claim 1, wherein portions of two adjacent sections of the enlarged portion are formed by a single intermediate electrode.   The apparatus of claim 1, wherein at least one section of the enlarged portion is formed by a single intermediate electrode.   The apparatus of claim 1, further comprising one or more suction channels.   The apparatus of claim 2, wherein the extension nozzle has one or more oxygen carrying gas inlets to the extension channel. A method of treating tissue using a pulse of plasma,
a. Generating a plasma flow;
b. Expanding the plasma flow to a predetermined cross-section;
c. Changing the thermal and energy density distribution of the expanded plasma stream so that the distribution is substantially uniform within the cross-section;
d. Applying the resulting plasma flow to the treated tissue;
e. Stopping the plasma flow;
Including repeatedly. The method of claim 13, wherein the energy density of each pulse is 5 to 500 J / cm ² or less.   14. The method of claim 13, further comprising removing foreign material from the treated tissue.   14. The method of claim 13, further comprising applying light to the treated tissue.   The method of claim 16, wherein the light has a dominant emission wavelength of 400 to 850 nm.   The method of claim 13, further comprising incorporating an oxygen carrying gas into the plasma stream.   19. The method of claim 18, wherein the plasma stream applied to the treatment tissue comprises ozone particles.   The method of claim 19, wherein the oxygen carrying gas is air.   The method of claim 19, wherein the treated tissue is skin.

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