Abstract:
An apparatus for producing a corona discharge and a method for producing a corona discharge is described. The apparatus comprises a voltage controlled oscillator (VCO) for producing an audio signal at an adjustable frequency. The VCO is controlled by a ramp generator, and the ramp generator causes the voltage controlled oscillator to continually adjust the frequency of the audio signal. The audio signal modulates a carrier signal produced by a pulse width modulated oscillator and the modulated carrier signal is provided to a coil assembly. The coil assembly is matched to the frequency of the carrier signal and produces a high voltage AC charge from the audio signal. A discharge pin discharges the high voltage AC charge in the form of an ionized corona from the coil assembly.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to the treatment and management of pain, and more particularly, a corona discharge apparatus suitable for use in medical and veterinary therapy. 
         [0003]    2. Description of the Related Art 
         [0004]    Thermotherapy is a safe and effective technique for treating various joint and muscle aches related to diseases such as arthritis, lower back pain, joint pain and temporomandibular joint (TMJ) pain. Corona discharge devices may be used by an individual or a healthcare provider to provide a safe, non-invasive thermotherapy treatment to an area of the body that suffers from such pain. 
         [0005]    An exemplary corona discharge apparatus is disclosed in U.S. Pat. No. 4,667,677 entitled “Corona Discharge Thermotherapy Technique”, U.S. Pat. No. 5,190,037 entitled “High-power Corona Discharge Beam Thermotherapy System”, and within U.S. Pat. No. 5,317,155 entitled “Corona Discharge Apparatus”, each of the above patents are herein incorporated by reference in their entirety. 
         [0006]    Arthritis is a condition which affects 1 out of every 7 people in the United States, and 1 out of every 5 adults. A USA TODAY article estimated that 50 million people in the U.S. suffer from arthritis. Arthritis is also the leading cause of disability for people over the age of 55 and costs the U.S. economy $128 billion annually. 
         [0007]    Lower back pain is another leading cause of disability. A PREVENTION magazine article stated that approximately 100 million people in the United States suffer from lower back pain. Americans spend over $50 billion annually on conventional and alternative therapy solutions seeking lower back pain relief. 
         [0008]    The worldwide market associated with pain relief solutions is easily in excess of $100 billion dollars. As people live longer, the market for pain relief with aging, arthritis, lower back pain, knees, hips, and joint pain will continue to grow. 
         [0009]    Unfortunately, known corona discharge apparatuses have shortcomings which limit their usefulness. Modern day corona discharge apparatuses operate at one set frequency to stimulate nerve cells and treat pain. Nerve cells undergo a phenomenon known as accommodation with each subsequent treatment by the corona discharge apparatus at a particular static frequency. During a therapy or treatment session, each subsequent treatment with the corona discharge apparatus at the static frequency is less effective than prior treatments due to accommodation of the nerve cells to the particular frequency. 
         [0010]    Thus, there is a need in the art to provide a corona discharge apparatus that reduces nerve cell accommodation during a therapy session. 
       SUMMARY OF THE INVENTION 
       [0011]    An apparatus for producing a corona discharge and a method of treating and managing pain with the apparatus is described. The apparatus comprises a voltage controlled oscillator (VCO) for producing an audio signal at a first frequency. The VCO is controlled by a ramp generator, and the ramp generator causes the voltage controlled oscillator to gradually adjust the frequency of the audio signal from the first frequency to a final frequency. The audio signal is placed onto a carrier signal by a modulator and carried to a coil assembly. The coil assembly is matched to the frequency of the carrier signal and produces a high voltage AC charge from the audio signal. A discharge pin discharges the high voltage AC charge in the form of an ionized corona from the coil assembly. By adjusting the frequency of the audio signal produced by the VCO, nerve cells are less likely to accommodate to the thermotherapy treatment from the apparatus. Thus, efficacy of thermotherapy treatment with the apparatus is increased. 
         [0012]    The method comprises generating an audio signal at a first frequency, gradually adjusting the audio signal from the first frequency to a final frequency, producing a high voltage AC charge from the gradually adjusted audio signal, and discharging an ionized corona produced from the high voltage AC charge over a treatment area. Treatment with the apparatus may be especially useful for treating TMJ, arthritis, lower back pain, knees, hips, and joint pain. Further, treatment with the apparatus is non-invasive and may be performed on an outpatient basis. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0014]      FIG. 1  is a general overview of a corona discharge apparatus; 
           [0015]      FIG. 2  is a cutaway view of a corona discharge gun utilized by the corona discharge apparatus; 
           [0016]      FIG. 3  is a schematic diagram of the internal circuitry of the corona discharge apparatus; 
           [0017]      FIG. 4  is a top-down view of a coil assembly utilized by the corona discharge apparatus; and 
           [0018]      FIG. 5  is a cross-sectional view of the coil assembly utilized by the corona discharge apparatus. 
       
    
    
       [0019]    While the invention is described herein by way of example using several embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modification, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0020]      FIG. 1  is a general overview of an exemplary embodiment of a corona discharge apparatus  100 . The corona discharge apparatus  100  comprises a control unit  102  coupled to a corona discharge gun  114  by a wire  112 . The apparatus  100  is coupled to a power source (not shown) such as a 15 volt power source, standard wall outlet or battery. 
         [0021]    The control unit  102  houses the internal circuitry (shown in  FIG. 3 ) that controls the operation of the apparatus  100 . The control unit  102  may be constructed from hard plastic, metal such as steel or aluminum, or any durable substance designed to withstand continual use in either a medical office environment or a harsh environment where animals or horses are housed. An “On/Off” switch  104 , power adjustment control  106  and frequency adjustment control  108  are integrated into the control unit  102  to facilitate operation of the apparatus  100 . The switches  104 / 106 / 108  may be rotary switches, potentiometers, slide switches, toggle switches, push button switches and the like. The control unit  102  is not limited to the controls  104 / 106 / 108 , and these controls  104 / 106 / 108  are only offered as an example of possible controls. 
         [0022]    The power switch  106  adjusts the amount of power supplied to the apparatus  100 . In one embodiment of the invention, the power switch  106  is a rotary dial with numeral settings of 0 to 10, 0 representing an off position and 10 representing maximum power supplied to the apparatus  100 . The apparatus  100  will generate a corona discharge at a higher voltage when the power switch  106  is set to the maximum power setting, i.e., 10. When the power switch  106  is set to a lower power setting, for example a power setting of 3, the apparatus  100  still produces a corona discharge but at a lower voltage. 
         [0023]    The frequency adjustment switch  108  is used to adjust and fine tune the frequency of the carrier signal produced by modulator. The modulator is shown in  FIG. 3  and discussed in further detail below. The frequency adjustment switch  108  is an optional part of the apparatus  100 . 
         [0024]    The corona discharge gun  114  is coupled to the control unit  102  by the wire  112 . The wire  112  may be an insulated coiled wire or any insulated wire capable of delivering an appropriate current from the control unit  102  to the gun  114 . The gun  114  may be made from a hard plastic or the same durable substance as the control unit  102 . 
         [0025]      FIG. 2  is a cutaway view of the corona discharge gun  114 . The internal circuitry of the gun comprises a coil assembly  202  and assembly core  203 , discharge pin  204 , resonant circuit node leads  206 , a connection to the power supply ground  208 , trigger switch  210 , trigger wire  212 . Also illustrated is the barrel  220  of the gun  114 , and insulative support structures  214  and  216 . The leads  206  are coupled to the coil assembly  202  and the trigger wire  212  is coupled to the trigger switch  210 . The leads  206  and the power supply ground  208  are encased in sheathing for the wire  112 . The wire  112  connects the gun  114  to the control unit  102  as shown above in  FIG. 2 . 
         [0026]      FIG. 3  is a schematic diagram of the internal circuitry  300  of the corona discharge apparatus  100 . The internal circuitry  300  comprises a timing mechanism  302 , a ramp generator  304 , an operational amplifier  305 , a voltage controlled oscillator (VCO)  306 , an enablement gate  308 , a pulse width modulated oscillator  310 , gating mechanism  312 , buffer  314  and capacitor  316 . Switch  104  couples the internal circuitry  300  to a power source (not shown). The timing mechanism  302 , ramp generator  304 , operational amplifier  305 , VCO  306 , enablement gate  308 , modulator  310 , gating mechanism  312 , buffer  314 , and switch  104  reside within the control unit  102  as shown in  FIG. 1 . The wire  112  connects the internal circuitry  300  of the control unit  102  to the internal circuitry of the gun  114  described above in  FIG. 2 . 
         [0027]    For ease of reference,  FIGS. 2 and 3  may be considered together to illustrate the operation of the corona discharge apparatus  100 . The apparatus  100  is operated by a user pushing switch  104  to supply power from a power source to the apparatus  100 . The power source may be any conventional power source, such as an electrical outlet or a battery, and a suitable amount of power from 10 volts to 110 volts is supplied to the apparatus. The switch  104  may be any conventional switch for connecting the power source to the apparatus  100  such as a push button switch, a trigger switch, a toggle switch and the like. 
         [0028]    Pushing the switch  104  triggers the timing mechanism  302 . The timing mechanism may be a 5-5-5 or a 5-5-6 timing mechanism. In one embodiment of the invention, the timing mechanism  302  allows for operation of the apparatus for a period of 20 seconds. The timing mechanism acts a failsafe mechanism that helps to prevent overheating of the apparatus  100 . The timing mechanism is coupled to the enablement gate  308 . 
         [0029]    The VCO  306  outputs an audio frequency within a range suitable for therapeutic thermotherapy treatment with the apparatus  100 . In one embodiment of the invention, the VCO outputs an audio frequency between 100 Hz and 1 kHz. The VCO  306  may be any conventional voltage controlled oscillator. As the voltage applied to the VCO  306  increases, the audio frequency outputted by the VCO  306  also increases. 
         [0030]    The VCO  306  is coupled to the operational amplifier  305  and the operational amplifier  305  is coupled to the ramp generator  304 . Suitable ramp generators and operational amplifiers are commercially available from Supertex Corp. of Sunnyvale Calif. The voltage of the ramp generator  304  increases from a minimum starting voltage to a maximum ending voltage over a period of time. At the end of the period of time, the ramp generator  304  resets itself back to the minimum starting voltage and “ramps up” or increases again to the maximum ending voltage. The period of time that the ramp generator takes to ramp up may correspond directly to the amount of time allowed by the timing mechanism  302 . For example, if the timing mechanism  302  allows the apparatus to operate for 20 seconds, then the ramp generator will reset from its maximum voltage to its minimum voltage every 20 seconds. 
         [0031]    The voltage output by the ramp generator  304  is coupled to the operational amplifier  305 , and the operational amplifier  305  is directly coupled to the VCO  306 . As the voltage supplied by the ramp generator  304  increases, the voltage supplied to the VCO  306  also increases. The increase in voltage supplied to the VCO  306  causes the frequency of the audio signal supplied by the VCO  306  to continually and gradually increase. However, it should be noted that at some point in time, the ramp generator  304  will reset itself to its minimum voltage. At this point, the audio frequency supplied by the VCO  306  will suddenly decrease to its minimum frequency. 
         [0032]    In one embodiment of the invention, the audio frequency supplied by the VCO  306  ranges from 100 Hz to 1 kHZ. When the ramp generator  304  reaches its maximum voltage, the VCO  306  will supply an audio signal at a frequency of 1 kHz. After the ramp generator  304  reaches its maximum voltage, the voltage automatically returns to its minimum voltage and likewise, the VCO  306  will supply an audio signal at a frequency of 100 Hz. In this manner, the audio frequency supplied by the VCO  306  is continually and gradually increasing from a frequency of 100 Hz to 1 kHz, and automatically returning to a frequency of 100 Hz. The audio frequency will continually cycle from a low frequency to a high frequency for the duration of time set by the timing mechanism  302 . 
         [0033]    The audio frequency supplied by the VCO  306  is passed on to the gating mechanism  308 . The gating mechanism  308  is also connected to the timing mechanism  302 . The gating mechanism  308  only allows for pass-through of the audio signal when a signal from the timing mechanism  302  is present. For example, if the timing mechanism  302  limits operation of the apparatus  100  for only 20 second intervals, the gating mechanism  308  only allows pass-through of the audio signal supplied by the VCO  306  during that 20 second interval. 
         [0034]    The gating mechanism  308  is coupled to the modulator  310 . The modulator  310  places the audio signal onto a carrier signal. In one embodiment of the invention, the carrier signal is set to a frequency of approximately 500 kHz. The carrier signal is set to a higher frequency than the audio signal and modulated by the audio signal. The modulator  310  is a pulse width modulator which controls the carrier signal by power adjustment and frequency adjustment. The amplitude of the carrier signal may be increased by increasing the power supplied to the modulator  310 , and likewise, the amplitude of the carrier signal may be decreased by decreasing the power. The carrier signal may be turned off completely by setting the frequency of the carrier signal to zero or the “off” position. The carrier signal may also be set to another frequency, e.g., 300 kHz, 800 kHz, etc., that provides more beneficial treatment of a patient. 
         [0035]    The modulator  310  is coupled to gating mechanism  312 . The gating mechanism  312  receives input signals from the timing mechanism  302  and the modulator  312 . The gating mechanism  312  allows pass-through of the audio signal on the carrier signal only when the carrier signal and the signal from the timing mechanism  302  are both present. The gating mechanism  312  provides passage of the audio signal on the carrier signal through to the buffer  314 . 
         [0036]    The buffer  314  may be a MOSFET driver. The buffer  314  stores the audio signal before passing on the audio signal from the control unit  102  to the corona discharge gun  114 . 
         [0037]    The capacitor  316  forms a series-resonant circuit with the coil assembly  202  to create a high voltage on the primary winding of the coil assembly. The high voltage on the primary winding is then stepped up to a higher voltage on the secondary winding of the coil assembly  202 . In one embodiment of the invention, the capacitor  316  is a 0.0015 microfarad capacitor, and the voltage on the primary winding is 10 kV which is stepped up to 100 kV on the secondary winding of the coil assembly  202 . 
         [0038]    Referring now to  FIG. 2 , the audio signal is passed on to the coil assembly  202  via resonant circuit node leads  206 . The coil assembly  202  is matched to the frequency of the carrier signal produced by the modulator  310 . The coil assembly  202  is described in further detail in  FIGS. 4 and 5 . The coil assembly  202  steps up the voltage from the power source to a voltage sufficient enough to produce a corona discharge from the discharge pin  204 . 
         [0039]    The coil assembly  202  may step up the voltage from 10 kV to 100 kV or greater. A corona discharge may be produced at 50 kV, and voltages stepped up by the coil assembly  202  to as high as 250 kV are also possible. The corona discharge ionizes the surrounding air, and the electrons in the air seek ground via the path of least resistance. The corona discharge also temporarily heats the surrounding air, allowing for thermotherapy treatment of an area in close proximity to the corona discharge. 
         [0040]      FIG. 4  is a top-down view of the coil assembly  202 , and  FIG. 5  is a cross-sectional view of the coil assembly  202  according to the embodiment of  FIG. 2 . As shown, the coil assembly is arranged in a substantially radial fashion. In one embodiment of the invention, a substantially cylindrical ferrite core  203  is at the center of the coil assembly  202 . The ferrite core  203  is at ground potential, and the voltage increases with increasing distance from the center. The highest voltage is at the outermost portion of the assembly  202 . The ferrite core  203  increases the Q, i.e., the inductive reactance, of the coil assembly  202 . 
         [0041]      FIG. 5  illustrates the construction of the core assembly  202 . The ferrite core  203  is at the innermost center of the assembly  202 . The ferrite core  203  has a diameter of approximately 1.1 inches and a length of approximately 3 inches. A layer of insulation  402  with an insulation capability of greater than 10 kV, such as insulating tape available from 3M Corp. of St. Paul, Minn., is wrapped around the ferrite core  203 . A primary winding  404  of wire is wrapped around the insulation  402  and the ferrite core  203 . In one embodiment of the invention, Litz 8/30 wire is utilized for the primary winding  404 . 
         [0042]    A second layer of high voltage insulating tape  406 , made from the same or similar material to the first layer of insulation  402 , is wrapped around the primary winding  404 . A slipover tube  408  is placed over the ferrite core  203 , first insulation layer  402 , the primary winding  404  and the second layer of insulating tape  406 . The outside of the slipover tube  408  is wrapped in a third layer of high voltage insulating tape  410 . The slipover tube may be constructed from polyoxymethylene or DELRIN. 
         [0043]    A secondary winding  412  is wrapped around the outside of the slipover tube  408 . In one embodiment of the invention, the secondary winding comprises 400 turns of Litz 8/30 wire. In this embodiment, the 400 turns are arranged in 20 layers, 20 turns per layer, each layer being separated from the next by respective layers of high voltage insulating tape. The outer layer of the secondary winding  412  is covered by a final layer of high voltage insulating tape. 
         [0044]    Leads  206  are connected to the primary winding  404  and the secondary winding  412  windings. The power supply lead  154  is connected to the primary winding  404 . An output lead  172  from the outermost periphery of the secondary winding  412  is coupled to the discharge pin  204 , is taken off the outermost periphery of the secondary winding  412 . 
         [0045]    The relationship between the secondary winding  412  and the primary winding  404  directly affects the amount of power needed to effectively operate the apparatus  100 . As disclosed in one embodiment above, the secondary winding  412  has 400 turns and the primary winding  404  has 40 turns, for a turn ratio of 10:1. In another embodiment of the invention, the turn ratio between the secondary winding  412  to the primary winding  404  is 1000:1. Less power is needed to operate the apparatus  100  as the ratio between the secondary winding  412  and the primary winding  404  increases. The apparatus  100  is less likely to overheat when operated at lower power. Therefore, increasing the ratio between the secondary winding  412  and the primary winding  404  is beneficial. 
         [0046]    A patient may be treated with the apparatus  100  by placing the corona discharge pin  204  within close proximity of a treatment area. The treatment area is any area affected by joint pain, muscle pain, arthritis, or any condition that may benefit from thermotherapy treatment. The apparatus  100  is set to an appropriate power level via the power adjustment switch  106  and the apparatus  100  is turned on by the on/off switch  104 . In one embodiment of the invention, a corona discharge is emitted from the discharge pin  204  on the gun  114  when a user presses the trigger switch  210 . In another embodiment of the invention, one or more corona discharges are emitted from the discharge pin  204  on the gun  114  over a period of time set by the timing mechanism  302 . 
         [0047]    Thus, the present invention provides an effective, non-invasive thermotherapy treatment for joint pain, muscle pain, arthritis and temporomandibular joint (TMJ) disorder. The apparatus utilizes a ramp generator to continually adjust the frequency of an audio signal produced by a voltage controlled oscillator. By continually adjusting the frequency of the audio signal, nerve cells are less likely to accommodate to thermotherapy treatment provided by the apparatus. 
         [0048]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.