Devices for creating non-thermal plasma and ozone

Abstract

A plurality of non-thermal plasma emitters is disposed on a rigid or flexible substrate. The rigid substrate enables the device to be pre-formed in any shape and the flexible substrate enables the device to conform to any surface topography at the time of treatment. The substrate is a dielectric material and in a preferred embodiment is made of thin FR-4. Each of the plasma emitters has a drive electrode on one side of the substrate and a ground electrode on the opposing side of the substrate. In the preferred embodiment both electrodes are centered over a through-hole in the substrate. A conductive drive track is connected to each drive electrode and a conductive ground track is connected to each ground electrode. A drive terminal is connected to the drive track and a ground terminal is connected to the ground track.

Claims

1. A non-thermal plasma device comprising: a. a substrate having a top surface and a bottom surface, the substrate having no through-holes between the top and bottom surfaces, the substrate made of a dielectric material; b. a plurality of drive electrodes on the top surface of the substrate; and c. a plurality of ground electrodes on the bottom surface of the substrate, such that a plurality of plasma emitters are formed on the surface of the substrate between the drive electrodes and the ground electrodes.

2. The device according to claim 1 wherein the substrate is flexible.

3. The device according to claim 2 wherein the substrate is made of FR-4.

4. The device according to claim 1 wherein each drive electrode and ground electrode are centered over each other.

5. The device according to claim 1 further comprising: a. a conductive drive track on the top surface of the substrate connected to each drive electrode; and b. a conductive ground track on the bottom surface of the substrate connected to each ground electrode.

6. The device according to claim 5 further comprising a drive terminal connected to the drive track and a ground terminal connected to the ground track.

7. The device according to claim 6 further comprising a voltage source connected to the drive terminal.

8. The device according to claim 7 wherein the voltage source is a cell phone.

9. The device according to claim 1 further comprising an insulative sheath covering at least a portion of the plasma emitters.

10. The device according to claim 1 wherein the plasma emitters are aligned in rows that are offset from the previous row.

11. The non-thermal plasma device of claim 1 wherein each of the ground electrodes comprises a sharp point.

12. A non-thermal plasma device comprising: a. a voltage source; b. a plurality of plasma emitters connected to one another to form an array such that, when the array is connected to the voltage source, a plurality of corona discharges is emitted from the plasma emitters; and c. a removable insulative sheath covering at least a portion of the plasma emitters.

13. The device according to claim 12 wherein the plasma emitters are formed in a flexible substrate.

14. The device according to claim 12 wherein the rigid substrate conforms to the shape of a human body part.

15. The device according to claim 12 wherein the plasma emitters are formed in a substrate that has the shape of a tube.

16. The device according to claim 12 wherein the sheath is removable.

17. A non-thermal plasma device comprising: a. a substrate having a top surface and a bottom surface, the substrate made of a dielectric material; b. a plurality of drive electrodes on the top surface of the substrate; c. a plurality of ground electrodes on the bottom surface of the substrate, with each ground electrode comprising a sharp point; and d. a plurality of through-holes in the substrate, wherein the drive electrodes and the ground electrodes are centered over the through-holes on the surface of the substrate such that a plurality of plasma emitters are formed in the substrate between the drive electrodes and the ground electrodes.

18. The device according to claim 17 further comprising: a. a conductive drive track on the top surface of the substrate connected to each drive electrode; b. a conductive ground track on the bottom surface of the substrate connected to each ground electrode; c. a drive terminal connected to the drive track and a ground terminal connected to the ground track; and d. a voltage source connected to the drive terminal.

19. The device according to claim 18 wherein the voltage source is a cell phone.

20. The device according to claim 17 further comprising a sheath made of PTFE covering at least a portion of the plasma emitters.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a top view of a first embodiment of a non-thermal plasma device of the present invention.

(2) FIG. 2 is a cross-sectional view of the device along line A-A of FIG. 1.

(3) FIG. 3 is a partial top view of a second embodiment of a non-thermal plasma device.

(4) FIG. 4 is a partial top view of a third embodiment of a non-thermal plasma device without through-holes in the substrate.

(5) FIG. 5 is a top view of a fourth embodiment of a non-thermal device with a woven array of plasma emitters.

(6) FIG. 6 is a schematic illustrating in perspective a portion of the woven array of FIG. 5.

(7) FIG. 7 is a photograph of the first embodiment of the device on a flexible substrate and its terminal connection points.

(8) FIG. 8 illustrates a general overview of a non-thermal plasma device with a controller and a power supply.

(9) FIG. 8A illustrates a general overview of a non-thermal plasma device with a controller and a cell phone power supply.

(10) FIG. 9 is a top view of a non-thermal plasma device that is partially covered with a flexible sheath.

(11) FIG. 10 is a top perspective view of rigid sheath partially covering a non-thermal plasma device.

(12) FIG. 11 is a top view of a fifth embodiment of a non-thermal plasma device of the present invention in which the plasma emitters are in a rectangular array.

(13) FIG. 12 is a top view of a sixth embodiment of a non-thermal plasma device of the present invention in which the plasma emitters are in a hexagonal array.

(14) FIG. 13 is a perspective view of a seventh embodiment illustrating a non-thermal plasma device as a tube.

(15) FIG. 14 illustrates plasma devices used to treat a patient's face in which several smaller devices are connected to each other to effectively create a larger area of plasma discharge.

(16) FIGS. 15A-D illustrate ground electrodes having points of various shapes.

DETAILED DESCRIPTION

(17) This device comprises a plurality of non-thermal plasma emitters, disposed on a rigid or flexible substrate. The emitters are arranged in an array such that when the array is connected to a voltage source the emitters generate a plurality of corona discharges. The discharges generate ionized gas, which in turn creates reactive species including ozone and nitric oxide.

(18) Referring initially to FIG. 1, a non-thermal plasma device is shown generally at 100. The device comprises a substrate 102 having at least two opposing surfaces, referred to herein sometimes as a top and bottom for convenience. A plurality of through-holes 118 is made in the substrate 102. A plurality of drive electrodes 110 is placed on the top of the substrate 102, with each drive electrode 110 centered over one through-hole 118 in the substrate 102. A plurality of ground electrodes 108 is placed on the bottom of the substrate 102, with each ground electrode 108 centered over one through-hole 118 in the substrate 102. The resulting structure of a through-hole, a ground electrode, and a drive electrode comprises a plasma emitter 107. FIG. 2 shows a cross-sectional view of a plasma emitter with through-holes. Each drive electrode 110 and ground electrode 108 is generally centered on a through-hole 118, but in certain embodiments it may be off-center. Each electrode's 110 shape is preferably symmetric around the through-hole 118, such as a hexagon, circle, triangle, rectangle, square, or other shape, but in certain embodiments can be asymmetric. FIGS. 1 and 3 illustrate an embodiment in which the drive electrode 110 is hexagonal.

(19) FIG. 4 shows another embodiment of a non-thermal and ozone plasma device 200 wherein a substrate does not have through-holes. Here a plurality of drive electrodes 110 is placed on the top of the substrate 102, with each drive electrode 110 centered over a ground electrode 108 on the bottom of the substrate 102. The resulting structure of a drive electrode on a dielectric substrate over a ground electrode is also referred to herein as a plasma emitter 107.

(20) A conductive drive track 112 on the top of the substrate 102 is connected to at least one drive electrode 110. A conductive ground track 104 on the bottom of the substrate 102 is connected to at least one ground electrode 108. One or more drive tracks 112 may be used to interconnect as many drive electrodes 110 together as desired. Similarly, one or more ground tracks 104 may be used to interconnect as many ground electrodes 108 together as desired. Emitters may be connected in series or in parallel, and preferably in parallel for a lower driving voltage.

(21) A drive terminal 111 is connected to the drive track 112 and a ground terminal 106 is connected to the ground track 104. The drive electrodes 110 are interconnected and connected to a drive terminal 111. Similarly, the ground electrodes are interconnected and connected to a ground terminal 106. The resultant structure is much like a printed circuit board.

(22) The substrate 102 is made of a dielectric material such as alumina, polycarbonate, polyimide, polyester, polytetrafluoroethylene-infused woven glass cloth, polypropylene, glass-reinforced epoxy laminate sheets, or the like. In certain embodiments a substrate has more than one layer, and the layers may be made of different materials. The substrate 102 is made of a rigid or a flexible material that can be made to conform to varying surface topography and shapes such as a rough surface, a textured surface, a smooth surface. The substrate can be two-dimensional, such as a square, curved, rectangular, round, or hexagonal. It can also be three-dimensional such as curved, cubic, tubular, or spherical.

(23) The substrate may also have a non-uniform shape or a non-symmetric shape. Substrates of rigid materials may be shaped to the desired conformation before or after the plasma emitters are made therein. Substrates of flexible materials are typically conformed to the desired shape after the device is manufactured.

(24) In a preferred embodiment, the substrate is made of thin FR-4. At a thickness of about 0.2 mm, the substrate made of FR-4 is somewhat flexible. As an alternative, the array can be fabricated from more flexible material such as polyimide film or PTFE infused fiberglass.

(25) Using mass manufacturing techniques, the cost of making the arrays is small enough that the devices can be considered consumable or disposable, simply thrown away or recycled after one or a few uses. Any polymer in the array is consumed by the oxygen plasma, in a process commonly known as ashing. This erosion process can be slowed by adding a thin layer of glass on top of the entire array. A sol-gel process can be used to deposit thick layer, on the order of about a 100 nm. A thinner crystalline layer of SiO2, Al2O3 or Y2O3 works too, and may be deposited by atomic layer deposition or plasma assisted atomic layer deposition, optionally after array burn-in for uniform plasma.

(26) A through-hole 118 helps reduce the array capacitance and is a ventilation hole for a fluid to flow from a drive electrode 110 to a ground electrode 108. Such fluids include oxygen, helium, nitrogen, sulfur hexafluoride, carbon dioxide, air, and other gases. In the preferred embodiment, the fluid is air at ambient pressure, about 1 atmosphere. The oxygen in the air is ionized by the plasma generated by the emitters 107, creating ozone. The through-holes 118 are made by drilling, etching, cutting, laser cutting, punching, or other method. In certain embodiments a through-hole is lined with a structure that directs the fluid to each electrode such as a pipe, tube, channel, or the like. A through-hole 118 can be circular, rectangular, triangular, trapezoidal, hexagonal, or other shape.

(27) A drive electrode 110 is capacitively coupled to ground electrode 108 at a point or points where the ground electrode touches the drive electrode such that when a high-enough voltage is applied to a drive electrode 110, the surrounding fluid is ionized and a plasma is created, causing electrons to flow between the drive and ground electrode.

(28) It is desirable to have a sharp point where the plasma is generated, since this is used to help initiate the plasma. The sharp points may take any form, such as a sharp point, a blunt point, a spear point a radius, or the like. FIG. 3 illustrates an embodiment in which the ground electrode 108 is a star with six sharp points 120. FIG. 4 illustrates an embodiment in which the ground electrode 108 is a triangle with three sharp points 120. FIG. 15A illustrates an electrode with six sharp points; FIG. 15B shows blunt points; FIG. 15C shows spear points; and FIG. 15D shows radius points.

(29) A drive electrode 110, drive track 112, ground electrode 108 and a ground track 104 can be printed, etched, laminated, or otherwise disposed onto the substrate 102. They can be made of copper, silver, nickel, or any other conductive material. The can be insulated, such as by a solder mask, polyester film such as Mylar, mica, polypropylene, polytetrafluoroethylene such as Teflon, or the like, and in other embodiments are not insulated. For manufacturing convenience, preferably the drive electrode 110 and ground drive 112 are made of the same material and disposed onto the substrate 102 at the same time. Similarly, preferably the ground electrode 108 and ground track 104 are made of the same material and disposed onto the substrate 102 at the same time. Alternatively the drive electrode 110, drive track 112, ground electrode 108 and a ground track 104 are made of different materials and may be disposed on the substrate in processes occurring at the same or different times.

(30) FIGS. 5 and 6 show another embodiment of a non-thermal device 100 wherein a plurality of plasma emitters 107 is created at the intersections of wires that are woven together. The wires 410 of drive electrode 408 are woven with the wires 406 of ground electrode 404 to form a woven array. One electrode is connected to a plurality of insulated wires and the other connected to a plurality of uninsulated wires. If the wire insulation is a polymer, a coating, such as SiO2, is preferred to prevent ashing. The air in the interstitial space between the wires is ignited to form a plasma. Wires can be copper, silver, nickel, or any other conductive material. The wires are insulated with non-conductive or dielectric materials such as plastic, rubber-like polymers, or varnish. In FIG. 5 the emitters 107 are covered by a rigid sheath 520 having hexagonal apertures 521.

(31) The drive terminal 111 and ground terminal 106 are printed, cut, punched, laminated, etched, connected, or otherwise attached to the drive track 112 and ground track 104, respectively. There are at least those two terminals for each array of emitters, but there may be as many terminals as desired. For example, there may be two terminals for each emitter 107, or there may be more than two terminals for each emitter 107, for example if extra terminals are desired for redundancy in case of failure, or to have better placement for connection to the voltage source. Preferably the terminals 111 and 106 are attached to or integral with the substrate, such as with solder pads, banana plugs, ring terminals, spade terminals, pin terminals, or the like.

(32) The emitters 107 can be arranged in a variety of relative positions, such as lines, concentric circles, random placement, etc. The arrangement of emitters is sometimes referred to herein as an array. An array can take on any shape to fit the user's needs. Typically the arrangement of the emitters 107 is generally symmetrical, such as a rectangle or hexagon, but the arrangement can be non-symmetrical too, which can be useful for using a single substrate target separate areas with different concentrations of plasma. FIG. 1 illustrates the emitters 107 arranged in rows, and each row is offset from the previous row. This same pattern is repeated with as many rows as the user needs to form the desired size of the array. The rows illustrated in FIG. 1 have 8 emitters each, but any number of emitters can be used in each row. The rows illustrated in FIG. 7 have 8 emitters each, but any number of emitters can be used in each row.

(33) The size of the array ranges from microscopic to macroscopic and, while theoretically unlimited, in practice is limited by manufacturing techniques. In practice, the arrays are typically less than 5 inches in any dimension. If a larger area of plasma discharge is desired, smaller arrays can be placed side-by-side and connected to each other to effectively create a larger array controlled as a single array. FIG. 14 illustrates plasma devices 100 used to treat a patient's face in which several smaller arrays are connected to each other to effectively create a larger area of plasma discharge. In other cases, the smaller arrays are placed sized-by-side to create a larger array, but are not connected to each other so that they can be controlled independently.

(34) Plasmas can be defined in a number of characteristics including size typically in meters), lifetime (seconds), density (particles per cubic meter) and temperature. In certain embodiments a first emitter 107 has a different plasma strength than a second emitter 107. The plasma strength is determined by a number of factors including dielectric thickness, drive voltage (which determines the duty cycle in which the plasma is ignited and retained), and atmospheric pressure. Typically the resultant plasma is fan shaped, extending about 0.8 mm from the point and about 120 degrees of fan.

(35) To create the plasma, a voltage is applied to one or more drive electrodes 110 with an AC power supply 506. The array is driven by a high voltage transformer, designed to resonate with the array capacitance. In a preferred embodiment, the power supply is a resonant transformer, with a half bridge driver on the transformer primary. The transformer primary bias is derived from a boost converter, which is connected to a rechargeable battery pack, charged by a cell phone charger connected to mains power, a cell phone, or a vehicle power outlet. See FIG. 8A. The characteristics of the power supply will depend on the size of the array. The inductance of the transformer's secondary winding and the capacitance of the array of emitters forms a parallel LC circuit with a particular resonant frequency.

(36) Preferably the voltage is controlled wirelessly or with wires by a controller 504. If using a wired controller, the controller 504 is connected to the device 100 by leads 502. See FIG. 8. The smart phone may also act as a programmable controller using a downloaded mobile application. In other embodiments the controller may be a customized control box, a desktop computer, a laptop, or the like. The controller can drive the transformer at its resonant frequency for the sake of power efficiency. If a therapeutic plasma frequency is found, the plasma frequency can be adjusted by adding parallel capacitance of an appropriate value. The AC drive voltage can also be modulated if a therapeutic modulation frequency is found. In an alternative embodiment, the transformer driver can be configured as an oscillator, so the transformer operates at the resonant frequency by default. In this case, a signal from the transformer driver is sent to the controller to synchronize the measurement of voltages and currents. This is can be used for accurate power measurement, for instance.

(37) The controller controls aspects that control the functionality of the device 100 such as time on/off, strength of plasma, strength of a plasma field from electrode to electrode, frequency, power, and the like. In certain embodiments the AC voltage is applied to the drive electrodes is on-off modulated in pulses, typically at a frequency between above 0 Hz to about 10 kHz. Alternatively a continuous wave voltage is applied to the drive electrodes. With the drive electrodes 110 at a high potential relative to the ground electrode 108, current flows through the drive electrodes 110 and through a fluid in the through-hole 118 and around the array. The fluid is ionized to create a plasma region around each drive electrode 110, ground electrode 108 or both. The ions from the ionized fluid pass a charge to a plurality of ground electrodes 108 or to an area of lower potential.

(38) FIG. 7 shows a non-thermal plasma device in which an insulative layer 304 is attached to the substrate 102, under the ground terminal 106 and driver terminal 111. The insulative layer 304 can be neoprene, polymer coating, Mylar, Teflon, or the like.

(39) FIG. 9 shows a non-thermal plasma device 100 with a sheath 520 covering at the plasma emitters. In some embodiments only some of the emitters are covered. In a preferred embodiment the sheath 520 is an electrical insulator that acts as a barrier between the device and a surface of interest. The electrical insulator 520 allows plasma generated from the device to effect and react with a surface of interest, but does not allow fluids to permeate thru the cover to the created plasma, and surface of a substrate. Thus it protects a user or surface from possible electrical shocks and prevents liquids from getting to the electrodes that might cause electrical shorts. Preferably the sheath 520 is flexible and made of PTFE, which provides a water-resistant yet breathable covering. Flexible sheaths can also be made of neoprene, hydrophobic polyester, hydrophilic polyether, or the like. FIG. 10 shows one embodiment of a rigid sheath 520 with apertures 521 centered on the through-holes 118 that are on the non-thermal plasma device. The sheath 520 can vary in length, width, and height to fit a non-thermal plasma device's size and shape.

(40) A non-thermal plasma device can conform to any shape or size, including human body parts. FIGS. 11, 12 and 13 show examples of additional embodiments of the device 100. FIG. 11 shows a rectangular array of plasma emitters 107 in which one side of the array is substantially longer than the other side. This arrangement may be particularly useful for the treatment of large narrow surface areas. FIG. 12 shows a hexagonal array of plasma emitters 107. FIG. 13 shows a device 100 formed into a tube, with plasma emitters arranged along the surface of the tube. This arrangement may be particularly useful for the treatment of tubular-shaped areas such as fingers so that the inside of the tube stays in contact with the outside of the finger. This arrangement may also be particularly useful for threating the inside surface of a tubular human body part such as an ear canal in which the outside of the tube stays in contact with the inner surface of the ear canal. The tubular device can be pre-formed on a rigid or flexible substrate. Alternatively, a rectangular device on a flexible substrate can be bent into a tube at the time of treatment.

(41) Plasma devices of the present invention can be used for treating many types of surfaces for purposes including cleaning, decontaminating, sterilization, and healing. For example:

Example 1

Decontamination of a Cell Phone

(42) Individuals take cell phones where everywhere they go and are constantly using it after using the restroom, touching dirty door knobs, shaking others' hands, sharing the phone with others, and touching money. All these items are full of bacteria, which can spread to the individual's cell phone. Consequently, cell phones have up to 18 times more bacteria than a public restroom. In certain embodiments a non-thermal plasma device can be placed around a cell phone. Once the non-thermal device is turned on the bacteria on the phone will be killed, in effect sanitizing the cell phone from any harmful bacteria.

Example 2

Biological Warfare Decontamination Suit

(43) In war biological weapons are used to kill and hurt soldiers. In certain embodiments a biological warfare suit can be lined with non-thermal plasma devices. When a soldier has been contaminated with a biological weapon, the soldier can put on the non-thermal-plasma lined suit. Once the suit is on, the non-thermal plasma devices are turned on and the soldier can be decontaminated. The suit is reusable.

Example 3

Killing Fungus or Bacteria with a Non-Thermal Plasma Device

(44) A voltage supplied to a plasma device can be modulated (pulsed or keyed on and off) at a rate of about 1 Hz to about 10 kHz. Specific modulation frequencies (the so-called Rife frequencies) have therapeutic effects in which a specific frequency is correlated to kill a specific microorganisms, including forms of bacteria, virus, fungus, mold, etc. The controller can use these frequencies to produce biological effects beyond those produced by reactive oxygen species. The resulting biological effects created by a non-thermal plasma device over a large surface area can eliminate microorganisms on any surface type.

Example 4

Method for Creating Ozone

(45) Ozone is an unstable, but highly beneficial molecule, and is created by plasma. Plasma is a mixture of neutral and charged particles. When a voltage is applied to an array of plasma emitters 107 that are in a gas containing oxygen, the plasma emitters generate a transfer of electrons that generates ozone. Ozone can be applied to a human body for therapeutic effects, to water for oxidizing pathogens and synthetics residues in the body, and to olive oil for ingesting which gives an individual a steady internal application of ozone. In addition, ozone can be used as an air disinfectant killing germs, infectious microorganisms, and neutralizing many biological problems like bacteria, viruses, mold and chemical outgassing.

Example 5

Cosmetic Treatments

(46) Nitric oxide is a free-radical that has been shown to be beneficial in treating photodamaged facial skin by burning the old damaged skin cells so they can be sloughed off and replaced with new, healthy skin cells. An array of plasma emitters that are in a gas containing nitrogen are placed on the desired treatment area of the skin and the plasma emitters generate nitric oxide across the entire treatment area. In this was treatment using the present device is much faster than the conventional method of treating the area with plasma plume that is repeatedly passed, or scanned, across the treatment area.

(47) While there has been illustrated and described what is at present considered to be the preferred embodiments of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the true scope of the invention. The embodiments of the invention described herein are not intended to be exhaustive or to limit the invention to precise forms disclosed. Rather, the embodiments selected for description have been chosen to enable one skilled in the art to practice the invention. Therefore, it is intended that this invention not be limited to the particular embodiments disclosed, but that the invention includes all embodiments falling within the scope of the appended claims.