WO2002054967A1 - Ensemble sonde, dispositif et systeme d'epilation rf - Google Patents
Ensemble sonde, dispositif et systeme d'epilation rf Download PDFInfo
- Publication number
- WO2002054967A1 WO2002054967A1 PCT/CA2001/000032 CA0100032W WO02054967A1 WO 2002054967 A1 WO2002054967 A1 WO 2002054967A1 CA 0100032 W CA0100032 W CA 0100032W WO 02054967 A1 WO02054967 A1 WO 02054967A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- coaxial cable
- probe assembly
- transformer
- hair removal
- output
- Prior art date
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
- A61B18/1206—Generators therefor
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
- A61B18/14—Probes or electrodes therefor
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
- A61B2018/00452—Skin
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
- A61B2018/00452—Skin
- A61B2018/00476—Hair follicles
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00636—Sensing and controlling the application of energy
- A61B2018/0066—Sensing and controlling the application of energy without feedback, i.e. open loop control
Definitions
- the present invention relates to a probe, a device and a system for RF epilation (hair removal) with a needle unit in a MHz range.
- FIG. 1 there is shown a simplified block diagram of a known RF type hair removal system.
- the system is composed of a tuned high power RF amplifier 3, a flexible coaxial cable 4, by which RF power is conducted, and a probe or needle assembly 5 by which the RF power is applied to treat the subject 6.
- An actuation device or actuator 1 is normally provided for user on-off control of the power applied by the probe to transfer power to the probe and needle assembly 5.
- the actuator 1 may take form of a foot pedal switch or a hand controlled device.
- the probe or needle assembly 5 is applied to a hair follicle of the subject 6, and after suitable power level settings of the system, the actuator 1 is used to apply RF power to the probe and needle assembly 5.
- the RF power amplifier frequency is usually set to 13.56 MHz and in Canada should be designed to operate to Government specifications dictated by: "Industry & Scientific Radio Frequency Generators" Document numbers: ICES-001 (English version) and NMB-001 (French version) .
- the RF power level and DC electrolysis levels have to be precisely set for specific time intervals. These adjustments are normally programmed in an electronics circuit 2 with control software and have been extensively described in Canadian Patent No. 2,011,693 (GHEDIN) , which discloses a method and an apparatus for removal of unwanted hair by using current modulation.
- the electronics circuit 2 and the R.F. amplifier 3 are usually contained as one assembly 76, the cable 4 and the needle assembly 5 as another assembly.
- the RF power level normally required to provide adequate hair removal can vary from fractions of a Watt to a maximum of 12 Watts at the probe/needle tip.
- a substantial voltage is necessary at the probe tip/needle, and usually is in the order of 120 V AC RMS at 13.56 MHz. This voltage is required because of the characteristic high impedance of the human body, which is typically 1,200 Ohms at 13.56 MHz.
- Typical coaxial cables have a characteristic impedance of about 50 Ohms and are preferred due to their low radiation properties and efficiency of RF power transfer. Most coaxial cables have a characteristic impedance varying from 30 Ohms to 100 Ohms.
- the characteristic impedance Z of a cable determines how the power flows through the cable, and in simple terms is defined as the ratio of the voltage to the current as defined by:
- the characteristic impedance of a coaxial cable can also be defined in terms of its geometric proportions, for example, the diameter D of its outer conductor 8, the diameter d of its inner conductor 9 and the permeability of the insulation 7 separating the two conductors 8, 9, as given by:
- the characteristics of a cable or transmission line can also be represented electrically as a "Pi" or "T” network, as shown in Figures 3A-B.
- 120 V of RF is required for hair removal, which means that 120 V has to be generated across the capacitive elements of the cable, whether it is the equivalent "Pi" or "T” network.
- Cables exhibit a certain distributed capacitance per foot of length and for a "RG174" type cable, the value is in order of 30 pF per foot. This means that for an unmatched transmission line, there are only a few resonant frequency points available (depending on the drive circuit) that can be effectively used for passing RF power.
- FIG 4 there is shown an equivalent output circuit with a tuned cable corresponding to a prior art system (the mesh currents are all clockwise) .
- the resultant frequency response is shown in Figure 5.
- the solid line represents 50 the voltage at the output, while the dotted line 52 represents the input current to the tuned tank circuit.
- the output is extremely sensitive to frequency which poses a problem of detuning with time.
- the high input currents also cause the output coaxial cable to heat up, causing reduction of cable life due to softening of the plastic insulating materials.
- An object of the present invention is to provide a more effective probe assembly, device, and system for MHz range RF hair removal, which have low production costs, and which do not suffer from the drawbacks of the prior art.
- Another object of the invention is to provide a probe assembly, device and system for MHz range RF hair removal, which have broadband RF characteristics, and which drastically reduce requirements of very high RF power levels contrary to prior art systems.
- Another object of the invention is to provide a device and a system for MHz range RF hair removal, which eliminate dependency on output cable characteristics, and which permit to use any cable length.
- Another object of the invention is to provide a device and system for MHz range RF hair removal, which do not suffer from cable heating, and short cable life.
- Another object of the invention is to provide a device and system for MHz range RF hair removal that are not sensitive to detuning.
- Another object of the invention is to provide a device and system for MHz range RF hair removal that is less affected by EMI.
- Another object of the present invention is to provide a matched impedance transmission line where all inductive and capacitive elements are effectively cancelled, whereas the input and output impedance appear totally resistive.
- a probe assembly for MHz range RF hair removal with a needle unit comprising : a coaxial cable input; a broadband, low power, impedance matching transformer having a primary winding coupled to the coaxial cable input, a secondary winding, and a high inductance and permeability core; and an output conductor connected to the secondary winding, for electrical connection to the needle unit.
- a RF hair removal device for MHz range hair removal with a needle unit, comprising: a probe assembly including a coaxial cable input, a broadband, low power, impedance matching transformer having a primary winding coupled to the coaxial cable input, a secondary winding, and a high inductance and permeability core, and an output conductor connected to the secondary winding for electrical connection to the needle unit; a RF generator unit including a power supply input, a control circuit coupled to the power supply input and generating a MHz range RF signal, and a tuning circuit coupled to the control circuit and locking the RF signal on a predetermined frequency; and a coaxial cable connected between the tuning circuit of the RF generator unit and the coaxial cable input of the probe assembly, the coaxial cable having an impedance to which an output impedance of the tuning circuit is matched.
- a RF hair removal system comprising: a probe assembly including a coaxial cable input, a broadband, low power, impedance matching transformer having a primary winding coupled to the coaxial cable input, a secondary winding, and a high inductance and permeability core, and an output conductor connected to the secondary winding; a needle unit connected to the output conductor; a RF generator unit including a power supply input, a control circuit coupled to the power supply input and generating a MHz range RF signal, and a tuning circuit coupled to the control circuit and locking the RF signal on a predetermined frequency; and a coaxial cable connected between the tuning circuit of the RF generator unit and the coaxial cable input of the probe assembly, the coaxial cable having an impedance to which an output impedance of the tuning circuit is matched.
- Fig. 1 is a schematic block diagram of a known hair removal system
- Fig. 2 is a perspective view of a known coaxial cable
- Figs. 3A and 3B are circuit diagrams respectively of equivalent T and Pi circuits of the coaxial cable;
- Fig. 4 is a circuit diagram of an equivalent output circuit with a tuned cable of a prior art system;
- Fig. 5 is a graphic showing the typical frequency response of the output circuit with tuned cable of Figure 4;
- Fig. 6 is a circuit diagram of a MHz range RF hair removal system according to the present invention.
- Fig. 7 is schematic view of a printed circuit board output transformer used in the RF hair removal system according to the present invention
- Fig. 8 is a section view of a probe assembly with a broadband, low power, impedance matching transformer according to the present invention
- Fig. 9 is a graphic showing input and output voltage and current for two load conditions for a RF hair removal system according to the present invention.
- Figs. 10A and 10B are front and side views of a first embodiment of a low power transformer used in the probe assembly according to the present invention
- Figs. 11A and 11B are front and side views of a second embodiment of a low power transformer used in the probe assembly according to the present invention.
- FIG. 8 there is shown a probe assembly 11 for MHz range RF hair removal according to the present invention.
- the probe assembly 11 is adapted to be used with a needle unit 23 that is plugged or otherwise connected at one end of the probe assembly 11.
- the probe assembly 11 is preferably made up of a sleeve- shaped electrically insulated handle 13 with a first end opening 15 for insertion of a coaxial cable 17. Part of the coaxial cable 17 is inserted inside the handle 13.
- the handle 13 also houses a broadband, low power, impedance matching transformer 19, which snugly fits inside the handle 13 and has its primary winding Start ' 0 ' to Tap '18' and total winding 58 (see Figs. 10B and 11B) coupled with the coaxial cable 17 through a coaxial cable input 54.
- the transformer is preferably positioned near the end of the probe assembly 11 so as to maximise power transfer to the probe tip.
- the low power transformer 19 has a high inductance and permeability core.
- the permeability is preferably greater than 100.
- FIGS. 10A, 10B, 11A and 11B two exemplary embodiments of low power transformer types that may be used with the probe assembly 11 are shown.
- the transformers have a ferrite suppression type bead 56 and a power rating of 7 Watts, but this can range substantially from at least 5 to 15 Watts.
- Ferrite bead transformers made by Fair-Rite TM provide good results.
- a special characteristic of RF permeable suppression bead cores is that they are highly resistive and may be wound directly on the core. This is a specific advantage of our particular embodiment.
- the low power transformer can be a suppression bead transformer having a volume of material of 0.207 cm 3 (16.34 in 3 ) and a power throughput of 8 Watts.
- the power density of the low power transformer is around 38 Watts/cm 3 (3000 Watts/in ) .
- the power dissipated in the core is 0.24 Watts, i.e. 1.15 Watts/cm 3 (90 Watts/in 3 ) .
- the preferred material types for this example are for use with low flux density devices and for EMI suppression low flux density operation to be below 10 MHz and suppression between 30 MHz to 200 MHz (it would not be apparent to persons trained in the art to use these power material types at 13.56 MHz) .
- the relationship between the inductive reactance vs the frequency maximizes between 10 MHz and 40 MHz.
- a preferred bead size has an outer diameter of 5.1 mm, an internal hole of 2.3 mm, and a length of 12.7 mm.
- Another feature of the low power transformer is that within the very small volume of the transformer, the voltage can be stepped up to 115 V to 120 V AC RMS at 13.56 MHz. Normally, insulation stresses would be prohibitive, but a choice of material with very high volume resistivity (greater than 10 5 Ohms cm) prevent field stresses occurring between the wire and the core (because there is no room to put additional insulation) . All power ferrite material have low volume resistivities (e.g. 10 3 Ohms cm).
- a good quality varnish or resin may be used to glue the wire in place (e.g. Krylon TM) .
- the total inductance of the low power transformer (at 10 KHz and 10 mV) is preferably about 1.4 mH. It is also preferable that the low power transformer 19 have an autotransformer closed magnetic toroidal configuration.
- the output voltage of the low power transformer is preferably 120 V for efficient hair removal .
- the ferrite core transformer is so designed to hide capacitance (or inductive) changes at the other end of the circuit caused by the load, and keeps the voltage/current ratio constant, e.g. 50 Ohms.
- the handle 13 preferably has an opposite end opening 21 for plug insertion of the needle unit 23 using an output connector 60 which is electrically connected to the secondary winding 62 (see Figs. 10B and 11B) of the low power transformer 19.
- a flexible coaxial cable is preferably used, otherwise the cable is likely to impede the user.
- Typical coaxial cables having an appropriate flexibility are RG174U (to MIL-C-17D) or any UL type 1354. These cables have a characteristic impedance of 50 Ohms .
- FIG. 6 there is shown a circuit diagram of the output section of a RF hair removal system according to the present invention.
- the system incorporates a device 25 and the needle unit 23.
- the device 25 is made of the probe assembly 11 and the coaxial cable 17 described above.
- the system also incorporates an RF generator unit 27.
- the RF generator unit 27 has a power supply input 29 which is coupled to a control circuit 31.
- the purpose of the control circuit 31 is to transform a DC current from a power supply (not shown) into an AC current signal.
- a tuning circuit 33 is coupled to the control circuit 31 in order to transfer matched RF power which is at predetermined frequency to the output cable 4.
- the shape of the RF signal is preferably a sinusoidal signal, but other shapes such as square or triangular can be also used if a tuned circuit is not implemented.
- the output impedance of the generator unit 27 is matched with the impedance of the coaxial cable 17.
- the output impedance of the tuning circuit 33 it is possible to adjust the output impedance of the tuning circuit 33 so that it matches exactly the impedance of the coaxial cable 17.
- an impedance matching output transformer 35 between the tuning circuit 33 and the coaxial cable 17, so that the output impedance of the generator unit 27 always matches the impedance of the coaxial cable 17.
- the output transformer 35 can be conveniently used also as a step up (or a step down) transformer depending on the power input.
- the primary and secondary windings 64, 66 of the output transformer 35 may conveniently be printed over adjacent layers of the printed circuit board of the generator unit 27.
- FIG. 9 there is shown input and output voltage and current for two load conditions of a RF hair removal system.
- the top two curves 68 and 70 which are almost superposed in the graph, represent the output voltage response for two "body loads” i.e. 1200 Ohms and 10,000 Ohms.
- the output response is flat and has a broadband characteristic for differing loads, which is not the case for the for prior art system, as shown in Figure 5.
- the bottom two curves 72 and 74 represent the input current for the two differing loads, and as can be seen, it is substantially less than that the one shown in Figure 5.
- the hair removal device and system of the present invention have the advantage of using a coaxial cable that is not stressed or heated and which can be of any length.
- the system has low EMI.
- the transformer within the probe assembly provides a broadband characteristic and drastically reduces the requirements of very high RF power levels as found in prior art systems.
- the power amplifier "sees" a resistive impedance for a large range of cable lengths. This "resistive impedance” is the reflection of the load, i.e. part of the human body, via the transformer arrangement which is not sensitive to tuning.
- the operating power of the RF amplifier in the invention is about 24 times less than standard systems.
- Output amplifier tuning is independent of the output cable and thus insensitive to the output cable length.
- the present system is not limited to fixed cable length or type of cable as any cable can be matched by design. Only low electromagnetic interference results from the present system since the output amplifier is relatively low.
Abstract
La présente invention concerne un ensemble sonde destiné à l'épilation RF dans la gamme des Mhz avec une aiguille. Cet ensemble sonde possède un câble coaxial d'entrée. Cet ensemble sonde possède aussi un transformateur d'impédance à l'adaptation, bande large et de faible puissance. Ce transformateur de faible puissance possède un enroulement principal couplé au câble coaxial d'entrée, un enroulement secondaire, et un noyau de haute inductance et perméabilité. Cet ensemble sonde possède aussi un conducteur de sortie connecté à l'enroulement secondaire, destiné à fournir une connexion électrique avec l'aiguille.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/CA2001/000032 WO2002054967A1 (fr) | 2001-01-15 | 2001-01-15 | Ensemble sonde, dispositif et systeme d'epilation rf |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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PCT/CA2001/000032 WO2002054967A1 (fr) | 2001-01-15 | 2001-01-15 | Ensemble sonde, dispositif et systeme d'epilation rf |
Publications (1)
Publication Number | Publication Date |
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WO2002054967A1 true WO2002054967A1 (fr) | 2002-07-18 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/CA2001/000032 WO2002054967A1 (fr) | 2001-01-15 | 2001-01-15 | Ensemble sonde, dispositif et systeme d'epilation rf |
Country Status (1)
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WO (1) | WO2002054967A1 (fr) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014016765A2 (fr) * | 2012-07-24 | 2014-01-30 | Lavy Lev | Sonde coaxial multicouche pour mesure de contraste spatial d'impédance |
US11137434B2 (en) | 2020-01-30 | 2021-10-05 | National Applied Research Laboratories | Active measuring probe for EMI detection |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3875945A (en) * | 1973-11-02 | 1975-04-08 | Demetron Corp | Electrosurgery instrument |
US3999552A (en) | 1975-05-20 | 1976-12-28 | Universal Technology, Inc. | Epilator |
US4167187A (en) | 1977-03-17 | 1979-09-11 | Kree Institute Of Electrolysis, Inc. | Dual epilation machine |
US4224994A (en) | 1979-06-21 | 1980-09-30 | Deere & Company | Single control for gas actuated fire extinguishers |
US4372315A (en) | 1980-07-03 | 1983-02-08 | Hair Free Centers | Impedance sensing epilator |
US4550728A (en) | 1982-08-23 | 1985-11-05 | L. P. Systems Corporation | Epilator |
US4566454A (en) | 1981-06-16 | 1986-01-28 | Thomas L. Mehl | Selected frequency hair removal device and method |
CA2011693A1 (fr) | 1990-03-07 | 1991-09-07 | Alphonse Ghedin | Methode et appareil d'epilation avec modulation de courant |
US5300068A (en) * | 1992-04-21 | 1994-04-05 | St. Jude Medical, Inc. | Electrosurgical apparatus |
US5785708A (en) | 1995-09-19 | 1998-07-28 | Lp Systems Corporation | Epilator probeholder |
CA2231383A1 (fr) | 1998-04-16 | 1999-10-16 | Silhouet Tone Appareils De Beaute Ltee | Combinaison manche, assemblage de tete d'aiguille et capuchon d'aiguille pour emploi dans un appareil d'epilation par electrolyse |
EP1034748A1 (fr) * | 1999-03-05 | 2000-09-13 | Gyrus Medical Limited | Electrobistouri à uhf |
-
2001
- 2001-01-15 WO PCT/CA2001/000032 patent/WO2002054967A1/fr active Application Filing
Patent Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3875945A (en) * | 1973-11-02 | 1975-04-08 | Demetron Corp | Electrosurgery instrument |
US3999552A (en) | 1975-05-20 | 1976-12-28 | Universal Technology, Inc. | Epilator |
US4167187A (en) | 1977-03-17 | 1979-09-11 | Kree Institute Of Electrolysis, Inc. | Dual epilation machine |
US4224994A (en) | 1979-06-21 | 1980-09-30 | Deere & Company | Single control for gas actuated fire extinguishers |
US4372315A (en) | 1980-07-03 | 1983-02-08 | Hair Free Centers | Impedance sensing epilator |
US4566454A (en) | 1981-06-16 | 1986-01-28 | Thomas L. Mehl | Selected frequency hair removal device and method |
US4550728A (en) | 1982-08-23 | 1985-11-05 | L. P. Systems Corporation | Epilator |
CA2011693A1 (fr) | 1990-03-07 | 1991-09-07 | Alphonse Ghedin | Methode et appareil d'epilation avec modulation de courant |
CA2011693C (fr) * | 1990-03-07 | 1995-08-22 | Alphonse Ghedin | Methode et appareil d'epilation avec modulation de courant |
US5300068A (en) * | 1992-04-21 | 1994-04-05 | St. Jude Medical, Inc. | Electrosurgical apparatus |
US5785708A (en) | 1995-09-19 | 1998-07-28 | Lp Systems Corporation | Epilator probeholder |
US5971982A (en) | 1995-09-19 | 1999-10-26 | Lp Systems Corporation | LPS 33 epilator and probeholder |
US5997535A (en) | 1995-09-19 | 1999-12-07 | Lp Systems Corporation | Control system for an epilation procedure |
CA2231383A1 (fr) | 1998-04-16 | 1999-10-16 | Silhouet Tone Appareils De Beaute Ltee | Combinaison manche, assemblage de tete d'aiguille et capuchon d'aiguille pour emploi dans un appareil d'epilation par electrolyse |
EP1034748A1 (fr) * | 1999-03-05 | 2000-09-13 | Gyrus Medical Limited | Electrobistouri à uhf |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014016765A2 (fr) * | 2012-07-24 | 2014-01-30 | Lavy Lev | Sonde coaxial multicouche pour mesure de contraste spatial d'impédance |
WO2014016765A3 (fr) * | 2012-07-24 | 2014-03-13 | Lavy Lev | Sonde coaxial multicouche pour mesure de contraste spatial d'impédance |
US11137434B2 (en) | 2020-01-30 | 2021-10-05 | National Applied Research Laboratories | Active measuring probe for EMI detection |
TWI750571B (zh) * | 2020-01-30 | 2021-12-21 | 財團法人國家實驗研究院 | 偵測電磁干擾之主動式量測探棒 |
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