(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization
`International Bureau
`
`(43) International Publication Date
`6 November 2003 (06.11.2003)
`
` (10) International Publication Number
`
`W0 03/090863 A1
`
`(51)
`
`International Patent Classificationlz
`
`A61N 2/02
`
`(21)
`
`International Application Number:
`
`PCT/KR03/00783
`
`(22)
`
`International Filing Date:
`
`17 April 2003 (17.04.2003)
`
`(25)
`
`Filing Language:
`
`(26)
`
`Publication Language:
`
`Korean
`
`English
`
`(30)
`
`Priority Data:
`10—2002—0022447
`
`24 April 2002 (24.04.2002)
`
`KR
`
`(71)
`
`(72)
`(75)
`
`Applicant 0’0)” all designated States except US): MCU-
`BETECHNOLOGY CO., LTD. [KR/KR]; Room #803,
`Sinnae—Technotown, 485, Sangbong—Dong, Jungnang—Gu,
`Seoul 131—220 (KR).
`
`Inventors; and
`Inventors/Applicants (for US only): KIM, Jung Hoe
`[KR/KR]; 713—901 Jinro APT, 654, Sinnae—Dong, Jung—
`nang—Gu, Seoul 131—130 (KR). LEE, S00 Yeol [KR/KR];
`304—304 Grandville,
`lll, Gumi—Dong, Bundang—Gu,
`
`Seongnam, Gyeonggi—Do 463—500 (KR). CHO, Min
`Hyoung [KR/KR]; 208—207 Garak Samick Mansion, 166,
`Songpa—Dong, Songpa—Gu, Seoul 138—170 (KR).
`
`(74) Agent: KIM, Yoon Bae; Kims and Lccs, International
`Patent and Law Offices, 8th Floor, Dongduk Building,
`151—8 Kwanhoon—Doug, Jongro—Gu, Seoul 110—300 (KR).
`
`(81) Designated States (national): AT, AU, BR, CA, CH, CN,
`CZ, DE, DK, ES, FI, GB, HU, ID, IL, IN, JP, LT, LU, MX,
`NO, NZ, PH, PL, PT, RO, RU, SE, SG, SK, TR, US, YU,
`ZA.
`
`(84) Designated States (regional): Eurasian patent (AM, AZ,
`BY, KG, KZ, MD, RU, TJ, TM), European patent (AT, BE,
`BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HU,
`IE, IT, LU, MC, NL, PT, RO, SE, SI, SK, TR).
`
`Published:
`
`7 with international search report
`
`For two-letter codes and other abbreviations, refer to the " Juid-
`ance Notes on Codes and Abbreviations " appearing at the begin-
`ning ofeach regular issue ofthe PCT Gazette.
`
`(54) Title: A STIMULATION COIL USING MAGNETIC MIRROR AND USE THEREOF
`
`
`
`(57) Abstract: The magnetic stimulation coil utilizes the magnetic mirror effect to stimulate nerves or muscles in the human body
`for diagnosis and therapy. The magnetic stimulation coil consists of a coil which generates a magnetic field using an electric current
`supplied from a power supply and a magnetic mirror which generates a magnetic field similar to the one generated by the coil. In
`this case, the magnetic mirror is made of ferromagnetic material which has high magnetic permeability. The magnetic stimulation
`coil with the magnetic mirror effect has advantages over a conventional techniques that it has better power efficiency and less heat
`generation. These advantages are very important in magnetic stimulators which are used for diagnosis and therapy in the hospital
`or for improvements and rehabilitations of impaired functions of a human being. Accordingly, the magnetic stimulation coil can be
`applied to various treatment devices such as urinary incontinence treatment, physical therapy, obesity treatment, arthritis treatment,
`and various kinds of health promoting devices.
`
`WO03/090863A1
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`TITLE OF THE INVENTION
`
`A stimulation coil using magnetic mirror and use thereof
`
`FIELD OF THE INVENTION
`
`The present
`
`invention relates to a magnetic stimulation
`
`coil
`
`in
`
`the diagnosis
`
`or
`
`treatment devices
`
`or health
`
`promoting devices which stimulate nerves or muscles in the
`
`human body by inducing electric field inside the nerves or
`
`muscles. Here,
`
`in order to induce the electric field,
`
`time
`
`varying magnetic field is applied to the human body.
`
`BACKGROUND OF THE INVENTION
`
`Until now, many techniques to stimulate nerves of muscles
`
`of the human body have been proposed. One of the examples is
`
`the paper,
`
`"Magnetic
`
`stimulation of
`
`the
`
`human brain",
`
`published by A. Barker in Journal of Physiology, vol. 369, pp
`
`3
`
`in
`
`1985.
`
`In
`
`the
`
`paper,
`
`an
`
`experimental
`
`result
`
`of
`
`stimulating human brains by a ngnetic stimulation coil
`
`is
`
`introduced.
`
`10
`
`15
`
`20
`
`Before the magnetic stimulation technology was introduced
`
`in the medical field,
`
`the electric stimulation method was
`
`25
`
`used,
`
`to
`
`stimulate
`
`human
`
`brains.
`
`Since
`
`the
`
`electric
`
`stimulation method was very invasive in that electrodes have
`
`to be attached to the brain after opening the skull,
`
`the
`
`electric stimulation method has not been widely used in the
`
`brain stimulation.
`
`30
`
`However, after
`
`the
`
`first publication about
`
`the brain
`
`-1-
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`stimulation
`
`using
`
`the magnetic
`
`stimulation
`
`coil, many
`
`researches on the magnetic stimulation of human nerves and
`
`muscles have been carried out.
`
`In 1991, R. Jalinous published
`
`a paper,
`
`"Technical and practical aspects of magnetic nerve
`
`stimulation" in Journal of Clinical Neurophysiology, vol.8,
`
`no.1,
`
`pp
`
`10—25,
`
`in which many
`
`technical aspects of
`
`the
`
`magnetic stimulation technology were described in detail.
`
`In
`
`the paper, applying a very intense electric current pulse,
`
`higher
`
`than several
`
`thousands of amperes,
`
`to a stimulating
`
`coil
`
`in a very‘ short
`
`time period,
`
`less than 1 msec,
`
`to
`
`stimulate the nerves or muscles in the human body is reported.
`
`This large coil current can make the magnetic field as large
`
`as several
`
`teslas around the stimulating coil. Since such a
`
`high current pulse is applied to the Hagnetic stimulation
`
`coil,
`
`the energy delivered to the coil can be as large as 500
`
`Joules per each current pulse and the power can be as large
`
`as BMW.
`
`Since the magnetic stimulation technology consumes such a
`
`large power
`
`in the
`
`stimulation of
`
`the
`
`human body,
`
`the
`
`stimulation repetition frequency had been limited to l-2Hz in
`
`the past. Therefore,
`
`the magnetic stimulation technology had
`
`been used only for diagnosis of diseases in nervous
`
`system
`
`with few exceptional uses in treatments.
`
`10
`
`15
`
`20
`
`Recently,
`
`there were several
`
`reports on applications of
`
`25'
`
`the magnetic
`
`stimulation to treatment areas. One of
`
`the
`
`examples
`
`is the paper,
`
`"Non—invasive
`
`treatment
`
`system for
`
`urinary incontinence using a continuous magnetic stimulation",
`
`published by N.
`
`Ishikawa et al.
`
`in Proceedings of 19th Int.
`
`Conference IEEE/EMBS (Chicago), pp 2096—2099 in Oct. 1997-
`
`In
`
`30
`
`the paper,
`
`N.
`
`Ishikawa
`
`et al.
`
`reported that magnetic
`
`

`

`W0 03/090863
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`PCT/KR03/00783
`
`stimulation of pelvic floor muscles and bladder nerves with
`
`the pulse repetition frequency of 5-30Hz can be used to treat
`
`urinary incontinence.
`
`In addition to the urinary incontinence
`
`treatment,
`
`there were publications reporting the efficacy of
`
`the magnetic stimulation in the treatment of deprementia.
`
`When
`
`the magnetic
`
`stimulation technology is
`
`applied to
`
`treatments,
`
`it is usual
`
`to apply magnetic pulses with the
`
`pulse repetition frequency of several tens of Hz. With such a
`
`high. pulse repetition frequency,
`
`it is inevitable to have
`
`high power consumption and excessive heat generation in the
`
`stimulating coil.
`
`There were also many
`
`techniques
`
`to supply high power
`
`electric current
`
`to the stimulating coil. U.S. Patent Nos.
`
`5,766,124 and 5,769,778 are among the examples. Here,
`
`to
`
`solve
`
`the
`
`problem of
`
`excessive
`
`heat
`
`generation
`
`in
`
`a
`
`stimulating' coil,
`
`the inventors have to either
`
`reduce the
`
`power
`
`consumption
`
`in the
`
`stimulating coil
`
`or
`
`cool
`
`the
`
`stimulating coil efficiently. Reducing the power consumption
`
`in the stimulating coil while maintaining the magnetic field
`
`strength generated by the coil will be the better way to
`
`solve the problem.
`
`10
`
`15
`
`20
`
`There
`
`are
`
`techniques
`
`to improve
`
`the stimulating coil
`
`efficiency in power consumption by optimizing the coil shape.
`
`For example,
`
`stimulating coil
`
`shapes suitable for urinary
`
`25
`
`incontinence treatment were introduced in U.S. Patent Nos.
`
`6,179,769 and 5,725,471, and stimulating coil shapes suitable
`
`for stimulating brain and peripheral nerves were introduced
`
`in U.S. Patent Nos. 4,056,0974 and 4,994,015.
`
`In summary, it
`
`is very essential to improve the coil efficiency and to use
`
`30
`
`an efficient coil cooling method in the magnetic stimulation
`
`-3—
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`with the pulse repetition frequency of several tens of Hz for
`
`treatments.
`
`SUMMARY OF THE INVENTION
`
`The present invention is to solve the problems in current
`
`magnetic
`
`stimulation technology described above,
`
`and
`
`to
`
`provide a stimulating coil
`
`to increase the Inagnetic field
`
`strength per unit current fed to the stimulating coil while
`
`10
`
`lowering the heat generation of the stimulating coil.
`
`To achieve the purpose described above,
`
`the stimulating
`
`coil according to the present invention comprising:
`
`(a) a coil made of metallic conductor; and
`
`(b)
`
`a magnetic mirror made of high magnetic permeability
`
`15
`
`material.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The features and advantages of the present
`
`invention will
`
`20
`
`be more clearly ‘understood.
`
`front
`
`the following‘ description
`
`taken in conjunction with the
`
`accompanying drawings,
`
`in
`
`which:
`
`Fig.
`
`l is a diagram of a magnetic stimulation coil using
`
`a magnetic mirror according to an embodiment of the present
`
`25
`
`invention;
`
`Fig.
`
`2
`
`is
`
`a
`
`diagram for
`
`explaining the operating
`
`principle of the magnetic mirror Shown in Fig. 1;
`
`Fig.
`
`3
`
`is
`
`a
`
`diagram for
`
`explaining the Operating
`
`principle of the magnetic mirror shown in Fig. 1;
`
`30
`
`Fig.
`
`4
`
`is a diagram showing the magnetic mirror made of
`
`_.4:_
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`laminated ferromagnetic plates to reduce eddy currents;
`
`Fig.
`
`5
`
`is a diagram for explaining the performance of a
`
`magnetic stimulation coil using the magnetic mirror according
`
`to an embodiment of the present invention;
`
`Fig.
`
`6
`
`ii;
`
`a diagram showing the performance comparison
`
`between the stimulating coils with and without
`
`the magnetic
`
`mirror effect;
`
`Fig.
`
`7
`
`is a diagram showing a
`
`shape of
`
`the magnetic
`
`mirror suitable for a 8—shaped stimulating coil;
`
`Fig.
`
`8
`
`is a diagram.
`
`showing a
`
`shape of
`
`the magnetic
`
`mirror suitable for a curved stimulating coil;
`
`Fig.
`
`9
`
`is a diagram for explaining a method efficiently
`
`cooling the heat generated in the stimulating coil;
`
`Fig.
`
`10
`
`is a. diagranl
`
`showing'
`
`a magnetic Inirror
`
`and a
`
`stimulating
`
`coil which
`
`are
`
`applicable
`
`to
`
`an
`
`urinary
`
`incontinence treatment device;
`
`Fig.
`
`11
`
`is a diagranl
`
`showing'
`
`a magnetic Inirror
`
`and.
`
`a
`
`stimulating coil which are applicable to an physical
`
`therapy
`
`device.
`
`DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
`
`There will now be described an embodiment of the present
`
`invention with reference to the accompanying drawings.
`
`The gist of the present invention is to improve the power
`
`consumption efficiency of a stimulating coil for stimulating
`
`nerves, muscles, and bones of the human body.
`
`In Fig.
`
`l,
`
`a preferred stimulating coil shape is shown.
`
`The stimulating coil consists of a coil
`
`1 made of metallic
`
`conductor
`
`and a
`
`Jnagnetic mirror'
`
`2 made of high. magnetic
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`W0 03/090863
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`PCT/KR03/00783
`
`permeability material.
`
`In Fig.
`
`l,
`
`the magnetic mirror has a
`
`circular shape, however,
`
`the magnetic mirror can have another
`
`shapes as described thereinafter. It is preferred that
`
`the
`
`coil
`
`1 and the magnetic mirror 2 are positioned to meet as
`
`closely as possible.
`
`The more
`
`closely the
`
`coil
`
`1
`
`is
`
`positioned to the mirror 2,
`
`the larger the magnetic mirror
`
`effect and 'the smaller‘ heat generation in the stimulating
`
`coil
`
`as
`
`described in hereinafter.
`
`In
`
`the
`
`conventional
`
`technologies,
`
`the magnetic stimulation coil consists of only
`
`a coil without a magnetic mirror.
`
`Electric current I is fed to the stimulating coil
`
`from an
`
`external
`
`power
`
`supply. Since
`
`the peak amplitude of
`
`the
`
`current
`
`supplied.
`
`to the stimulating coil
`
`is
`
`as
`
`large as
`
`several hundreds or several thousands of amperes, it is usual
`
`to use high 'voltage capacitors to charge electric charges
`
`supplied from the external power
`
`supply and discharge the
`
`charged
`
`electric
`
`charges
`
`to
`
`the
`
`stimulating
`
`coil
`
`instantaneously.
`
`In
`
`this
`
`case,
`
`the
`
`capacitor
`
`and
`
`the
`
`stimulating coil form a LC resonant circuit, and the resonant
`
`frequency is about several KHz. When electric current
`
`flows
`
`along the coil, magnetic field is generated. The magnetic
`
`field can penetrate the tissues of the human body since most
`
`of biological
`tissues are magnetically transparent. When a
`stimulating coil
`is used to stimulate tissues of
`the human
`
`body,
`
`the stimulating coil can have various shapes. We have
`
`shown a circular coil,
`
`the most frequently used coil,
`
`in Fig.
`
`l,
`
`the present
`
`invention applies
`
`to the
`
`coil with an
`
`arbitrary shape.
`
`In Fig. 2, basic principle of
`
`the present
`
`invention is
`
`illustrated. For
`
`the purpose of explanation, we assume that
`
`10
`
`15
`
`20
`
`25
`
`30
`
`-6...
`
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`

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`
`the coil consists of an infinitely long wire 3.
`
`In Fig. 2,
`
`the coil wire points perpendicularly to the paper. Around the
`
`wire,
`
`there is a magnetic material
`
`4 parallel
`
`to the wire
`
`with the distance d. It is assumed that the magnetic material
`
`has
`
`an
`
`semi—infinite
`
`shape.
`
`In
`
`the present
`
`invention,
`
`magnetic material means the substance which as high magnetic
`
`permeability. That
`
`is, when an external magnetic field is
`
`applied to
`
`the magnetic material,
`
`strong magnetization
`
`appears inside the magnetic material making dense magnetic
`
`flux inside the material. There are many kinds of magnetic
`
`materials,
`
`such
`
`as
`
`ferrite,
`
`silicon
`
`steel,
`
`permalloy,
`
`permendure, metallic glass,
`
`and
`
`powder
`
`iron. Magnetic
`
`permeability of air
`
`is
`
`about
`
`4><3.l4><10q.
`
`The magnetic
`
`permeability of ferrite is several hundred times larger than
`
`that of air,
`
`and the magnetic permeability of silicon steel
`
`is several thousand times larger than that of air.
`
`When a magnetic material
`
`is located around the coil wire
`
`3 as shown in Fig. 2,
`
`inventors of the present invention have
`
`to consider the magnetic field generated by the magnetization
`
`inside the magnetic material as well as the magnetic field
`
`generated by
`
`the wire.
`
`If
`
`the magnetic material has
`
`an
`
`infinite size and the magnetic permeability of the material
`
`is much higher than that of air,
`
`the magnetic field around
`
`the wire can be calculated as if there is an imaginary wire 5
`
`instead of the magnetic material carrying the same current as
`
`that of
`
`the wire. The magnetic field calculation method in
`
`such a way
`
`is called image method or mirror method. The
`
`mirror method can be found in most electromagnetism texts.
`
`In Fig.
`
`3,
`
`the principle
`
`of
`
`the mirror method
`
`is
`
`schematically illustrated. Only perpendicular magnetic field
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`component exists on the surface of a magnetic material. That
`
`is,
`
`the magnetic flux vectors meet
`
`the magnetic material
`
`perpendicularly on its surface. The left Side of Fig.
`
`3 shows
`
`such a
`
`shape using magnetic flux lines
`
`6. The
`
`shape of
`
`magnetic flux vectors generated around a wire with magnetic
`
`material is same as the shape of the magnetic flux vectors 7
`
`of the case that there are a wire without magnetic material
`
`and another
`
`imaginary wire located at
`
`the distance 2d from
`
`the wire carrying the electric current of the same amplitude
`
`and direction. This is illustrated in the right side of Fig.
`
`3. When
`
`the permeability of
`
`the magnetic material
`
`is not
`
`infinite,
`
`the shape and the position of
`
`the imaginary wire
`
`are changed. However,
`
`its disagreement with the case of
`
`infinite
`
`permeability
`
`can
`
`be
`
`neglected,
`
`since
`
`the
`
`permeability of ferrite or silicon steel
`
`is several hundred
`
`times larger than that of air. If the wires of Fig.
`
`2 and Fig.
`
`3 are regarded as stimulating coils,
`
`it can be found that
`
`there is additionally an imaginary stimulating coil
`
`inside
`
`the magnetic material.
`
`If
`
`the distance,
`
`d between
`
`the
`
`magnetic material and a coil is zero,
`
`a stimulating coil and
`
`a imaginary coil are overlapped each other, and the effect
`
`that
`
`the
`
`same
`
`shape of
`
`a magnetic
`
`field as
`
`that of
`
`a
`
`stimulating coil
`
`is added can be obtained.
`
`In other words,
`
`the effective strength of a magnetic field can be increased
`
`twice by using just one
`
`stimulating coil
`
`and.
`
`a magnetic
`
`mirror.
`
`When
`
`the material of
`
`a Inagnetic Inirror
`
`is chosen,
`
`the
`
`high permeablity and the ability to reduce an eddy current
`
`should
`
`be
`
`considered. Theoretically,
`
`the
`
`fact
`
`that
`
`a
`
`imaginary coil is made inside the magnetic material requires
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`-8—
`
`

`

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`
`the assumption that its electrical conductivity is zero, or
`
`the applied current is a direct current. The current pulse of
`
`a few hundreds usec is usually applied to a coil stimulating
`
`the human body. Therefore,
`
`if the electrical conductivity of
`
`the magnetic material
`
`is not
`
`zero,
`
`an
`
`eddy current
`
`generated.
`
`in Inagnetic lnaterial. Since the eddy current
`
`generated in the opposite direction of the coil current,
`
`is
`
`is
`
`it
`
`reduces
`
`the magnetic field strength. ThOugh ferrite has
`
`a
`
`very low conductivity, its permeablity is not high. Since the
`
`saturation magnetic flux density of ferrite is 0.4—0.5 teslas
`
`and a stimulating coil makes magnetic flux density of
`
`1—2
`
`teslas, ferrite is not a proper material.
`
`In order to avoid a
`
`magnetic saturation,
`
`the present invention uses silicon steel,
`
`not ferrite. Silicon steel has
`
`some advantages of its low
`
`cost
`
`and high saturation magnetic
`
`flux density over 2.0
`
`teslas. However,
`
`the high conductivity of silicon steel can
`
`make
`
`a
`
`.large eddy current. To
`
`reduce a <eddy' current,
`
`the
`
`present
`
`invention uses
`
`laminated silicon steel plates
`
`as
`
`shown in Fig. 4. Since silicon steel plates are coated with
`
`an insulator,
`
`eddy currents cannot
`
`flow between plates, but
`
`can flow inside a plate. Therefore,
`
`the generation of eddy
`
`currents
`
`is restrained.
`
`and the reduction of
`
`the Inagnetic
`
`10
`
`15
`
`20
`
`field generated by a imaginary coil becomes very small.
`
`In Fig.
`
`2 and Fig. 3,
`
`the infinite size of the magnetic
`
`25
`
`material
`
`is assumed.
`
`In order to analyze the effect of the
`
`magnetic mirror made of
`
`a magnetic material with a finite
`
`size,
`
`the model as shown in Fig.
`
`5
`
`is constructed. The size
`
`of the magnetic material plate 11 with a circular shape is
`
`recommended.
`
`to be
`
`a
`
`little bit
`
`larger
`
`than that of
`
`the
`
`30
`
`circular coil 10 in Fig. 5. The circle coil can be made of
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`enameled wires. Using a
`
`finite element method.
`
`(FEM), we
`
`carried out
`
`a
`
`simulation to obtain magnetic flux vectors
`
`about the model of Fig. 5. Inventors of the present invention
`
`used
`
`the
`
`simulation
`
`software
`
`provided by Vector Field
`
`Corporation for an electro—magnetic analysis using an FEM.
`
`Fig.
`
`6 shows the simulation result. The solid and dotted
`
`lines of Fig.
`
`6 represent
`
`the strength of the magnetic flux
`
`density of
`
`the cases with and without
`
`a Jnagnetic Inirror,
`
`respectively.
`
`In the
`
`simulation,
`
`the width of
`
`the coil,
`
`Wl=5mm,
`
`the thickness of
`
`the magnetic mirror, W2=15mm,
`
`the
`
`inner radius of the coil, Rl=lOmm,
`
`the outer radius, R2=55mm,
`
`the
`
`outer
`
`radius
`
`of
`
`the mirror,
`
`R3=75mm were
`
`used
`
`respectively. The magnetic material was made of silicon steel
`
`mentioned in the above.
`
`In this case,
`
`the inductance of the
`
`stimulating‘ coil was
`
`assumed.
`
`to be
`
`5011H. The
`
`jperformance
`
`comparison should be carried out under the condition of the
`
`same inductance value. The current flowing along the coil is
`
`a shape of
`
`a damped sinusoidal wave and the its frequency
`
`depends on 'the inductance <xf
`
`the coil.
`
`A. stimulating‘ coil
`
`with a magnetic mirror can have about twice larger inductance
`
`than the one without it. Therefore,
`
`inventors of the present
`
`invention designed the coil without a magnetic mirror so that
`
`its inductance is 5014H. The current
`
`flowing along the coil
`
`was 2,000A.
`
`The
`
`result of Fig.
`
`6
`
`illustrates the values along the
`
`center axis of the parallel plane 5mm distant from the coil.
`
`This
`
`result
`
`shows
`
`that
`
`the magnetic flux density in the
`
`center of the coil increases from 0.92 teslas to 1.36 teslas
`
`by using a magnetic mirror. The increase rate of the magnetic
`
`10
`
`15
`
`20
`
`25
`
`30
`
`field in this case is upto about 48%.
`
`-10—
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`On
`
`the other hand,
`
`inventors of
`
`the present
`
`invention
`
`performed the practical experiment
`
`to verify the previously
`
`mentioned simulation result. All
`
`inductances of
`
`the used
`
`stimulating coils were adjusted to 5011B. The inner and outer
`
`radii of the coil were 10mm and 60mm,
`
`respectively. And the
`
`thickness of the magnetic mirror was 15mm and its radius was
`
`75mm. The magnetic mirror was made of laminated silicon steel
`
`plates. The thickness of silicon steel plates was
`
`1mm. The
`
`plates were properly cut and stacked. When the current of
`
`2,000A was
`
`fed to the stimulating coil,
`
`the measured result
`
`showed that
`
`the magnetic flux density in the center of the
`
`coil with the magnetic mirror was about 33% larger than that
`
`of the case without it. The difference between 48% increase
`
`of the simulation result and 33% of the experimental result
`
`is due to the eddy current generated.
`
`inside the magnetic
`
`mirror.
`
`Even though.
`
`the desirable conductivity' of
`
`the magnetic
`
`mirror is ideally zero,
`
`that of a silicon steel plate is very
`
`high. Therefore,
`
`even the laminated magnetic mirror cannot
`
`remove all eddy currents.
`
`In order to reduce the effect of
`
`the eddy current as much as possible,
`
`the plate should be
`
`very thin.
`
`Another simulation was carried out
`
`to analyze the effect
`
`of
`
`the thickness of the magnetic mirror. The result
`
`showed
`
`that the effects were almost same for the thickness of 15mm,
`
`20mm,
`
`and 25mm. It means
`
`that
`
`the effect of
`
`the magnetic
`
`mirror may" be
`
`saturated, when
`
`its thickness gets over
`
`a
`
`critical value. On the contrary,
`
`if its thickness gets under
`
`a critical value,
`
`the saturation of magnetic flux density
`
`inside the mirror may occur
`
`and.
`
`the effect
`
`is
`
`reduced.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`-11..
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`However,
`
`it
`
`is inevitable to use a
`
`thin mirror
`
`for
`
`some
`
`applications,
`
`and the reduction of
`
`the effect
`
`should be
`
`accepted.
`
`The additional advantage of
`
`the magnetic Inirror
`
`is to
`
`reduce the heat generated in the stimulating coil. When the
`
`number of
`
`turns
`
`of
`
`the
`
`stimulating coil
`
`increases,
`
`its
`
`electrical
`
`resistance gets larger. The nmgnetic mirror can
`
`reduce
`
`the
`
`number
`
`of
`
`coil
`
`turns
`
`and
`
`the proportional
`
`resistance, and finally the heat generated in the coil can be
`
`reduced. The following table 1 shows the measured temperature
`
`of the stimulating coil surface, when the pulse duration and
`
`the frequency of the applied current were Soollsec and SOHz,
`
`respectively. The current pulse was a bipolar pulse and its
`
`amplitude was 2,000A.
`
`10
`
`15
`
`Table l. The surface temperature of the stimulating coil
`
`
`initial after after after after after After
`
`state
`
`1 min. 2 min. 3 min.
`
`4 min. 5 min.
`
`6 min.
`
`100.2
`
`114.2
`
`IIiiliIIlIiiiillliiiilIiiililliiliilIliililllliilill
`
`
`
`
`
`
`
`
`Without the
`
`magnetic
`
`mirror-
`
`With the
`
`magnetic
`
` mirror
`
`The
`
`table IL
`
`represents that
`
`the surface temperature of
`
`the stimulating‘ coil
`
`can fall
`
`down by 'using the magnetic
`
`20
`
`mirror. If the temperature rise of the coil is reduced,
`
`the
`
`higher frequency of the stimulating pulse can be used and the
`
`capacity of the cooler chilling the coil can be reduced.
`
`._.12_.
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`The shape of the stimulation coil is not always circular.
`
`Fig.
`
`7
`
`illustrates the 8-shaped coil 14 which is widely
`
`used. This 8—shaped coil
`
`is composed of two circular coils.
`
`It is widely used for selectively stimulating a specific area,
`
`since the magnetic flux can be focused at the place where two
`
`circles meet each other. The magnetic mirror 15 can be also
`
`applied for this 8—shaped coil.
`
`In this case,
`
`the shape of
`
`the mirror may not be circular and a little bit larger size
`
`than that of the 8—shaped mirror is recommended. The shape of
`
`the magnetic mirror can be varied according to the shape of
`
`the stimulating coils. Even though the circular shape of the
`
`mirrOr is the most desirable, a rectangle or a polygon larger
`
`than the coil can be used in consideration of manufacturing
`
`convenience. And the magnetic mirror can be applied to the
`
`coil with a curved surface,
`
`too.
`
`The
`
`curved.
`
`surface had
`
`better be parallel to the coil surface.
`
`Fig.
`
`8
`
`.illustrates the curved surface of
`
`the magnetic
`
`mirror 17 which is suitable to stimulate a human brain.
`
`In order to efficiently cool down the heat generated in
`
`the stimulating coil and the magnetic mirror,
`
`the opposite
`
`side of
`
`the magnetic mirror
`
`can be made uneven. Fig.
`
`9
`
`illustrates an uneven shape of the magnetic mirror 20 which
`
`is made by stacking Inagnetic material. plates 18,
`
`19 with
`
`different widths. This is an efficient structure to cool down
`
`10
`
`15
`
`20
`
`25
`
`the magnetic mirror.
`
`Fig. 10 illustrates the shape of the stimulating coil and
`
`the magnetic mirror which are applicable to the treatment of
`
`urinary incontinence.
`
`In the urinary incontinence treatment
`
`using the magnetic stimulation,
`
`a patient
`
`is usually seated
`
`30
`
`at
`
`a chair
`
`and the stimulating coil
`
`21
`
`and.
`
`the magnetic
`
`._.13__
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`mirror 22 are generally installed inside a seat 23.
`
`Fig. 11 illustrates the shape of the stimulating coil and
`
`the magnetic mirror which
`
`are
`
`applicable
`
`to a physical
`
`therapy. Since the stimulating coil for a physical
`
`therapy
`
`are generally attached to the structure like an artificial
`
`arm,
`
`it is desirable to attach, both. of
`
`the coil
`
`and.
`
`the
`
`magnetic mirror to an artificial arm 24.
`
`The
`
`stimulating coil
`
`and the magnetic mirror
`
`can be
`
`closely adhered
`
`each other
`
`in
`
`the various ways
`
`using
`
`nonconductive glue,
`
`thread,
`
`ribbon, etc. And it is possible
`
`to insert the material with high thermal conductivity between
`
`the coil
`
`and.
`
`the mirror‘
`
`in order
`
`to cool
`
`down
`
`the heat
`
`generated in the coil through the mirror.
`
`As explained in the above,
`
`the present
`
`invention can
`
`provide the stimulating coil with the magnetic mirror, which
`
`can
`
`reduce
`
`the
`
`required electric power
`
`and
`
`the
`
`heat
`
`generation by' enhancing‘
`
`the efficiency of
`
`the stimulating
`
`coil. The stimulating coil
`
`is used to stimulate the human
`
`body, magnetically for the function diagnosis of nerves and
`
`muscles, urinary incontinence treatment, physical
`
`therapy,
`
`the pain relief, obesity treatment, etc.
`
`The present
`
`invention has been described.
`
`in terms of
`
`preferred embodiments. However, it should be understood that
`
`the present
`
`invention is not
`
`limited in its application to
`
`the
`
`specific embodiments. Those
`
`skilled in the art will
`
`recognize that various modifications and variations may be
`
`made without departing fron1 the spirit
`
`and scope of
`
`this
`
`invention, as defined in the following claimsa
`
`10
`
`15
`
`20
`
`25
`
`30
`
`_14_.
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`< References >
`
`1. A.
`
`T. Barker et al.,
`
`"Magnetic
`
`stimulation of
`
`the
`
`human brain", Journal of physiology, Vol. 369, pp 3, 1985
`
`2.
`
`R.
`
`Jalinous,
`
`"Technical
`
`and practical
`
`aspects of
`
`magnetic
`
`nerve
`
`stimulation",
`
`Journal
`
`of
`
`Clinical
`
`Neurophysiology, Vol. 8, No. 1, pp 10—25, 1991
`
`3. N.
`
`Ishikawa et al.,
`
`"Non—invasive treatment system for
`
`urinary incontinence using a continuous magnetic stimulation",
`
`Proceeding 19th Int. Conference IEEE/EMBS pp 2096-2099, 1997.
`
`10
`
`10.
`
`4.
`
`U.S.
`
`Patent
`
`No.
`
`5,766,124,
`
`entitled.
`
`"Magnetic
`
`stimulator for neuro—muscular tissue"
`
`5. U.S. Patent No. 5,769,778, entitled "Medical magnetic
`
`non—convulsive stimulation therapy"
`
`15
`
`6. U.S. Patent No. 6,179,769, entitled "Magnetic stimulus
`
`type urinary incontinence treatment apparatus"
`
`7. U.S. Patent No. 5,725,471, entitled "Magnetic nerve
`
`stimulator for exciting peripheral nerves,
`
`8.
`
`U.S.
`
`Patent
`
`No.
`
`4,994,015,
`
`entitled.
`
`"Magnetic
`
`20
`
`stimulator coils"
`
`9. U.S.
`
`Patent No.
`
`4,056,097,
`
`entitled "Contactless
`
`stimulus transducer"
`
`__.15._
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`WHAT IS CLAIMED IS:
`
`1.
`
`A stimulating coil comprising:
`
`(a)
`
`a coil generating a magnetic field by an electric
`
`current supplied from an external power supply; and
`
`(b)
`
`a magnetic Inirror
`
`Inade of
`
`Inagnetic material and
`
`located on the opposite side of
`
`the stimulating region of
`
`said coil
`
`in order to strengthen a magnetic field generated
`
`by said coil.
`
`2.
`
`A stimulating coil as claimed in claim 1, wherein said
`
`magnetic mirror is composed of laminated magnetic material in
`
`order to reduce an eddy current and heat generated in said
`
`magnetic mirror.
`
`3.
`
`A stimulating coil as claimed in claim 1, wherein the
`
`other side of said magnetic mirror not contacted by said coil
`
`is uneven in order to efficiently reduce heat generated in
`
`said magnetic mirror.
`
`4.
`
`A
`
`stimulating coil
`
`as
`
`claimed in claim 1,
`
`the
`
`overlapping area of said magnetic mirror and said coil is 10%
`
`larger than said coil.
`
`5.
`
`A magnetic stimulator performing diagnosis,
`
`therapy,
`
`and.
`
`functional
`
`improvement by stimulating the human body
`
`magnetically with a stimulating coil
`
`in any one of claims 1
`
`to 4.
`
`6.
`
`A urinary incontinence treatment device stimulating
`
`_16_
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`pelvic muscles
`
`and. nerves magnetically with.
`
`a stimulating
`
`coil in any one of claims 1 to 4.
`
`7.
`
`A physical therapy device reducing pain by stimulating
`
`a human body magnetically with a stimulating coil in any one
`
`of claims 1 to 4.
`
`8.
`
`A obesity treatment
`
`device
`
`curing
`
`obesity by
`
`stimulating muscles
`
`and
`
`nerves magnetically with
`
`a
`
`10
`
`stimulating coil in any one of claims 1 to 4.
`
`_17__
`
`

`

`00000000000
`
`
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`N.mE
`
`1H
`
` 3.53233:32.:
`
`2/8
`
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`Fig.3
`
`
`MaterialWWI.irI\
`
`
`H.Magnetic
`
`OJ \ 00
`
`

`

`00000000000
`
`
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`m.mmm
`
`33:32
`
`3.3th
`
`IT
`éEsp
`
`5/8
`
`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`B[Tesla]
`
`
`
`0.0
`
`1.0
`
`2.0
`
`3.0
`
`4.0
`
`5.0
`
`6.0
`
`7.0
`
`8.0
`
`9.0
`
`10.0
`
`r[cm]
`
`
`
`

`

`
`

`

`W0 03/090863
`
`PCT/KR03/00783
`
`
`
`24
`
`26
`
`25
`
`8/8
`
`

`

`INTERNATIONAL SEARCH REPORT
`
`PCT/KRO3/00733
`
`A.
`
`CLASSIFICATION OF SUBJECT MATTER
`
`national application No.
`
`IPC7 A61N 2/02
`
`According to International Patent Classification (IPC) or to both national classification and IPC
`B.
`FIELDS SEARCHED
`
`Minimum documentation searched (classification system followed by classification symbols)
`IPC7 A61 N, H01F
`
`as searc e
`
`Documentation scare e- at Ier t tan minimum nocumentation to tie extent t at suc
`
`- ocuments are inc u e-
`
`’
`
`Electronic data base consulted during the intertnational search (name of data base and, w are practica- e, search terms used)
`KIPONET, DELPHION
`
`
`C. DOCUIWENTS CONSIDERED TO BE RELEVANT
`
`Catcgory*
`
`Citation of document, with indication, where appropriate, of the relevant passages
`
`Relevant to claim No.
`
`EP 1145738 A2 (N ihon Kohden Corporation) 17 OCTOBER 2001
`See the whole document
`
`1—3, 5-8
`
`See the whole document
`
`JP 04-72705 A(Mitsubishi Electric Corp) 06 MARCH 1992
`See the Whole document
`
`US 6179769 Bl(Nihon Kohden Corporation) 30 JANUARY 2001
`See the whole document
`
`US 5997464 A(Blackwe11] 07 DECEMBER 1999
`See the whole document
`
`1
`
`1
`
`1, 6
`
`l-3
`
` US 5078674 A(Cadwell) 07 JANUARY 1992
`
`*
`"A"
`
`D Further documents are listed in the continuation of Box C.
`Special categories of cited documents:
`document defining the general state of the artwhich is not considered
`to be of particular relevance
`‘
`earlier application or patent but published on or alter the international
`filing date
`document which may throw doubts on priority clai1n(s) or which is
`cited to establish the publication date of citation or other
`special reason (as specified)
`document referring to an oral disclosure, use, exhibition or other
`means
`document published prior to the international filing date but later
`than the priority date claimed
`
`"T"
`
`PEI See patent family annex.
`later document published afier the international filing date or priority
`date and not
`in conflict with the application but cited to understand
`the principle or theory underlying the inVEntlon
`"X" document of particular relevance; the claimed invention cannot be
`considered novel or cannot be considered to involve an inventive
`step when the document is taken alone
`.,
`"Y" document of particular relevance; the claimed invention cannot be
`considered to involve an inventive step when the document is
`combined with one or more other such doeuments,such combination
`being obvious to a person skilled in the art
`"&" document member of the same patent family
`
`
`
`Date of mailing of the international search report
`
`
`
`"E"
`
`"L"
`
`"0"
`
`"P"
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Date of t