(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2008/0197957 A1
`Kondo et al.
`(43) Pub. Date:
`Aug. 21, 2008
`
`US 20080 197957A1
`
`(54) COIL UNIT AND ELECTRONIC
`INSTRUMENT
`
`(75) Inventors:
`
`O
`O
`Yoichiro Kondo, Chino-shi (JP);
`Hirofumi Okada, Suwa-shi (JP)
`
`Correspondence Address:
`OLIFF & BERRIDGE, PLC
`P.O. BOX 320850
`ALEXANDRIA, VA 22320-4850
`
`(73) Assignee:
`
`SEIKO EPSON
`CORPORATION, TOKYO (JP)
`
`(21) Appl. No.:
`
`12/071,255
`
`(22) Filed:
`
`Feb. 19, 2008
`
`
`
`20(20A)
`
`Foreign Application Priority Data
`(30)
`Feb. 20, 2007 (JP) ................................. 2007-039890
`Dec. 20, 2007 (JP) ................................. 2007-328.245
`Publication Classification
`
`(51) Int. Cl.
`(2006.01)
`HOIF 27/02
`(2006.01)
`HOIF 5/00
`336/
`(52) U.S. Cl. ........................................... 336/90; 336/200
`(57)
`ABSTRACT
`A coil unit includes a planar air-core coil that has an air-core
`section, a printed circuit board that is disposed on a transmis
`sion side of the planar air-core coil, and a magnetic sheet that
`is disposed on a non-transmission side of the planar air-core
`coil opposite to the transmission side. The planar air-core coil
`includes a lead line connected to an inner end of the planar
`air-core coil over the transmission side, and the printed circuit
`board includes a receiving section that receives the lead line.
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`Patent Application Publication
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`Aug. 21, 2008 Sheet 1 of 12
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`US 2008/O197957 A1
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`F.G. 1
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`
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`10(10A)
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`Aug. 21, 2008 Sheet 2 of 12
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`US 2008/O197957 A1
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`FIG 2
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`
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`Aug. 21, 2008 Sheet 3 of 12
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`US 2008/O197957 A1
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`FIG 3A
`
`40B
`
`70
`
`CSS-S-S-S-S-AYS-S-S-S-S-S-S SN
`
`S&S
`
`FG, 3B
`
`
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`Aug. 21, 2008 Sheet 4 of 12
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`US 2008/O197957 A1
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`FIG 4
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`
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`Patent Application Publication
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`Aug. 21, 2008 Sheet 5 of 12
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`US 2008/O197957 A1
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`FGS
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`
`
`50
`
`60b
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`Aug. 21, 2008 Sheet 6 of 12
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`US 2008/O197957 A1
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`FIG 6
`
`60a
`
`32
`
`60
`
`32
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`Aug. 21, 2008 Sheet 7 of 12
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`US 2008/O197957 A1
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`Patent Application Publication
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`Aug. 21, 2008 Sheet 8 of 12
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`US 2008/O197957 A1
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`FG. 8
`
`
`
`20a
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`Aug. 21, 2008 Sheet 9 of 12
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`US 2008/O197957 A1
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`FG, 9
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`Patent Application Publication
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`Aug. 21, 2008 Sheet 10 of 12
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`US 2008/O197957 A1
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`FIG 10
`
`
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`Aug. 21, 2008 Sheet 12 of 12
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`US 2008/O197957 A1
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`F.G. 13
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`Aug. 21, 2008
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`COL UNIT AND ELECTRONIC
`INSTRUMENT
`
`0001 Japanese Patent Application No. 2007-39890 filed
`on Feb. 20, 2007 and Japanese Patent Application No. 2007
`328245 filed on Dec. 20, 2007, are hereby incorporated by
`reference in their entirety.
`
`BACKGROUND OF THE INVENTION
`
`0002 The present invention relates to a coil unit relating to
`non-contact power transmission using a coil, an electronic
`instrument, and the like.
`0003) Non-contact power transmission which utilizes
`electromagnetic induction to enable power transmission
`without metal-to-metal contact has been known. As applica
`tion examples of non-contact power transmission, charging a
`portable telephone, a household appliance (e.g., telephone
`handset), and the like has been proposed.
`0004. In power transmission utilizing electromagnetic
`induction, the amount of deviation of a coil from the coaxial
`line affects the amount of power transmission to a large
`extent. Therefore, it is important that a charging target be
`placed at an appropriate position of a charger. The following
`technologies have been proposed in order to appropriately
`position the charging target with respect to the charger.
`0005 JP-A-6-311659 discloses technology which pre
`vents insertion of a foreign object between a charging target
`and a charger so that charging occurs at an appropriate posi
`tion.
`0006 JP-A-7-322534 discloses electromagnetic coupling
`technology in which a protruding core is inserted into an
`air-core solenoid coil.
`0007 JP-A-6-303726 discloses technology which pro
`duces primary/secondary electromagnetic coupling by insert
`ing a primary-side core into an air-core section of a second
`ary-side coil.
`0008. In the above technologies, the core is provided in the
`coil.
`
`SUMMARY
`
`0009 Aspects of the invention may provide a thin coil unit
`which enables an increase in power transmission efficiency,
`an electronic instrument including the same, and the like.
`0010. Another aspect of the invention may define an elec
`tronic instrument including a housing that receives the above
`coil unit.
`0011. According to one aspect of the invention, there is
`provided a coil unit comprising:
`0012 a planar air-core coil that has an air-core section;
`0013 a printed circuit board that is disposed on a trans
`mission side of the planar air-core coil; and
`0014 a magnetic sheet that is disposed on a non-transmis
`sion side of the planar air-core coil, the non-transmission side
`being opposite to the transmission side,
`00.15
`the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil over the
`transmission side; and
`0016 the printed circuit board including a receiving sec
`tion that receives the lead line.
`
`0017. According to another aspect of the invention, there
`is provided a coil unit comprising:
`0018 a planar air-core coil that has an air-core section;
`0019 a magnetic sheet that is disposed on a non-transmis
`sion side of the planar air-core coil opposite to a transmission
`side; and
`0020 a printed circuit board that is disposed on a side of
`the magnetic sheet opposite to a side that is disposed over the
`planar air-core coil,
`0021 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil over a side
`that faces the magnetic sheet; and
`0022 the printed circuit board including a receiving sec
`tion that receives the lead line through the magnetic sheet.
`0023. According to another aspect of the invention, there
`is provided a coil unit comprising:
`0024 a planar air-core coil that has an air-core section;
`0025 a coil-receiving housing that is disposed on a trans
`mission side of the planar air-core coil; and
`0026 a printed circuit board that is disposed on a non
`transmission side of the planar air-core coil,
`0027 the printed circuit board being fixed on the coil
`receiving housing so that the planar air-core coil is placed
`between the coil-receiving housing and the printed circuit
`board;
`0028 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil over the
`transmission side; and
`0029 the coil-receiving housing including a receiving
`section that receives the lead line.
`0030. According to another aspect of the invention, there
`is provided a coil unit comprising:
`0031 a planar air-core coil that has an air-core section;
`0032 a printed circuit board that is disposed on a trans
`mission side of the planar air-core coil; and
`0033 a magnetic sheet that is disposed on a non-transmis
`sion side of the planar air-core coil,
`0034 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil, the lead line
`being provided on the transmission side; and
`0035 the printed circuit board including a receiving sec
`tion that receives the lead line.
`0036. According to another aspect of the invention, there
`is provided a coil unit comprising:
`0037 a planar air-core coil that has an air-core section;
`0038 a magnetic sheet that is disposed on a non-transmis
`sion side of the planarair-core coil, a first side of the magnetic
`sheet being placed on the planar air-core coil; and
`0039 a printed circuit board that is disposed on a second
`side of the magnetic sheet,
`0040 the planar air-core coil including a lead line that
`connected to an inner end of the planar air-core coil, the lead
`line being provided on the non-transmission side; and
`0041 the printed circuit board including a receiving sec
`tion that receives the lead line.
`0042. According to another aspect of the invention, there
`is provided a coil unit comprising:
`0043 a planar air-core coil that has an air-core section;
`0044 a coil-receiving housing that is disposed on a trans
`mission side of the planar air-core coil; and
`0045 a printed circuit board that is disposed on a non
`transmission side of the planar air-core coil,
`0046 the printed circuit board being fixed on the coil
`receiving housing:
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`0047 the planar air-core coil being placed between the
`coil-receiving housing and the printed circuit board;
`0048 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil on the
`transmission side; and
`0049 the coil-receiving housing including a receiving
`section that receives the lead line.
`0050. According to another aspect of the invention, there
`is provided an electronic instrument comprising one of the
`above coil units.
`
`BRIEF DESCRIPTION OF THE SEVERAL
`VIEWS OF THE DRAWING
`FIG. 1 is a view showing a first embodiment having
`0051
`a charger and a portable telephone horizontally placed on the
`charger.
`0052 FIG. 2 is an oblique view showing a coil unit.
`0053 FIGS. 3A and 3B are cross-sectional views sche
`matically showing a cross section of a coil unit along a line
`VII-VII shown in FIG. 2.
`0054 FIG. 4 is an exploded oblique view showing a coil
`unit.
`0055 FIG. 5 is an exploded oblique view showing another
`example of a coil unit.
`0056 FIG. 6 is a view showing the relationship between a
`receiving section of a printed circuit board and a lead line.
`0057 FIG. 7 is an exploded oblique view showing a fur
`ther example of a coil unit.
`0058 FIG. 8 is an exploded oblique view showing a coil
`unit having a coil-receiving housing.
`0059 FIG.9 is an exploded oblique view showing the coil
`unit shown in FIG. 8 at a different angle.
`0060 FIG. 10 is a view schematically showing a first
`manufacturing step of the coil unit shown in FIG. 8.
`0061
`FIG. 11 is a view schematically showing a second
`manufacturing step of the coil unit shown in FIG. 8.
`0062 FIG. 12 is a view schematically showing a third
`manufacturing step of the coil unit shown in FIG. 8.
`0063 FIG. 13 is a view schematically showing a fourth
`manufacturing step of the coil unit shown in FIG. 8.
`
`DETAILED DESCRIPTION OF THE
`EMBODIMENT
`0064. According to one embodiment of the invention,
`there is provided a coil unit comprising:
`0065 a planar air-core coil that has an air-core section;
`0066 a printed circuit board that is disposed on a trans
`mission side of the planar air-core coil; and
`0067 a magnetic sheet that is disposed on a non-transmis
`sion side of the planar air-core coil, the non-transmission side
`being opposite to the transmission side,
`0068 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil over the
`transmission side; and
`0069 the printed circuit board including a receiving sec
`tion that receives the lead line.
`0070 The lead line of the inner end of the coil increases
`the thickness of the planar air-core coil. However, since the
`lead line is placed in the receiving section of the printed
`circuit board, a situation in which the entire thickness of the
`lead line increases the thickness of the coil unit (planar air
`core coil--magnetic sheet-printed circuit board) can be pre
`vented, whereby the thickness of the coil unit can be reduced.
`
`0071. In the coil unit, the printed circuit board may include
`a through-hole that faces an air-core section of the planar
`air-core coil.
`0072. When the through-hole is formed in the printed cir
`cuit board, the coil unit can be positioned with respect to a
`housing which receives the coil unit by inserting a coil posi
`tioning protrusion provided on the housing into the air-core
`section of the planar air-core coil through the through-hole.
`0073. In the coil unit,
`0074 a diameter of the through-hole that is formed in the
`printed circuit board may be smaller than a diameter of the
`air-core section of the planar air-core coil; and
`0075 the coil unit may further include a temperature
`detection section that is provided on a side of the printed
`circuit board that is placed over the planar air-core coil, the
`temperature detection section being provided at a position
`that is near the through-hole and inside an edge of the air-core
`section.
`0076. The coil unit may further include a temperature
`detection section that is provided on a side of the printed
`circuit board opposite to a side that is placed over the planar
`air-core coil, the temperature detection section being pro
`vided at a position on a periphery of the through-hole.
`0077. In either case, since a temperature can be detected
`near the air-core section of the planar air-core coil, the tem
`perature of a foreign object positioned between an electronic
`instrument and a charger can be appropriately measured. This
`makes it possible to take measures (e.g., disconnection from
`power supply) when the temperature has increased to a value
`equal to or higher than a given value.
`0078. According to another embodiment of the invention,
`there is provided an electronic instrument comprising a hous
`ing that receives one of the above coil units. In this case, the
`housing of the electronic instrument may include a coil posi
`tioning protrusion that is formed on an inner Surface of the
`housing, the coil positioning protrusion being inserted into
`the air-core section of the planar air-core coil through the
`through-hole that is formed in the printed circuit board to
`position the planar air-core coil.
`0079 According to another embodiment of the invention,
`there is provided a coil unit comprising:
`0080 a planar air-core coil that has an air-core section;
`0081 a magnetic sheet that is disposed on a non-transmis
`sion side of the planar air-core coil opposite to a transmission
`side; and
`I0082 a printed circuit board that is disposed on a side of
`the magnetic sheet opposite to a side that is disposed over the
`planar air-core coil,
`I0083 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil over a side
`that faces the magnetic sheet; and
`I0084 the printed circuit board including a receiving sec
`tion that receives the lead line through the magnetic sheet.
`0085. In this case, a situation in which the entire thickness
`of the lead line increases the thickness of the coil unit (planar
`air-core coil--magnetic sheet-printed circuit board) can be
`prevented, whereby the thickness of the coil unit can be
`reduced.
`I0086. In an electronic instrument including the above coil
`unit, since the printed circuit board is not provided between
`the planar air-core coil and a housing of the electronic instru
`ment, a through-hole need not beformed in the printed circuit
`board. The coil unit can be positioned with respect to the
`housing by inserting a coil positioning protrusion provided on
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`
`the housing of the electronic instrument into the air-core
`section of the planar air-core coil. Since the planar air-core
`coil can be disposed in contact with the inner surface of the
`housing, the distance between the coil units is reduced,
`whereby transmission efficiency increases.
`0087. A coil unit according to another embodiment of the
`invention may integrally include a coil-receiving housing
`which forms part of a housing of a charger or an electronic
`instrument.
`0088 According to another embodiment of the invention,
`there is provided a coil unit comprising:
`a planar air-core coil that has an air-core section;
`0089
`0090 a coil-receiving housing that is disposed on a trans
`mission side of the planar air-core coil; and
`0091 a printed circuit board that is disposed on a non
`transmission side of the planar air-core coil,
`0092 the printed circuit board being fixed on the coil
`receiving housing so that the planar air-core coil is placed
`between the coil-receiving housing and the printed circuit
`board;
`0093 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil over the
`transmission side; and
`0094 the coil-receiving housing including a receiving
`section that receives the lead line.
`0095 According to this configuration, a rigid structure in
`which the planar air-core coil is placed between the coil
`receiving housing and the printed circuit board can be pro
`vided before incorporating the coil unit in a housing of an
`electronic instrument or a charger. This improves the assem
`bling properties of the coil. Moreover, a situation in which the
`entire thickness of the lead line increases the thickness of the
`coil unit can be prevented, whereby the thickness of the coil
`unit can be reduced.
`0096. According to this structure, a situation in which the
`coil is unwound or deformed during transportation or incor
`poration of the coil can be prevented, whereby deformation of
`the coil which may adversely affect electrical properties such
`as inductance can be prevented.
`0097. According to this configuration, the coil-receiving
`housing may include a positioning protrusion that positions
`the planar air-core coil.
`0098. The coil unit may further include a magnetic sheet
`that is disposed on the non-transmission side of the planar
`air-core coil. According to this configuration, the planar air
`core coil and the magnetic sheet may be placed between the
`coil-receiving housing and the printed circuit board.
`0099. According to another embodiment of the invention,
`there is provided an electronic instrument comprising the coil
`unit, an outer Surface of the coil-receiving housing may be
`flush with an outer surface of a housing of the electronic
`instrument. Specifically, the coil-receiving housing forms
`part of the housing of the electronic instrument so that the side
`placed on a charger is made flat.
`0100. In the electronic instrument, the housing of the elec
`tronic instrument may include a positioning target section
`that determines a position of a charger. This enables the
`electronic instrument to be positioned with respect to the
`charger, whereby transmission efficiency increases.
`0101 The above-described structure which absorbs the
`thickness of the lead line may also be applied to the charger.
`
`0102) According to another embodiment of the invention,
`there is provided a coil unit comprising:
`0103) a planar air-core coil that has an air-core section;
`0104 a printed circuit board that is disposed on a trans
`mission side of the planar air-core coil; and
`0105 a magnetic sheet that is disposed on a non-transmis
`sion side of the planar air-core coil,
`0106 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil, the lead line
`being provided on the transmission side; and
`0107 the printed circuit board including a receiving sec
`tion that receives the lead line.
`0108. According to another embodiment of the invention,
`there is provided a coil unit comprising:
`0109 a planar air-core coil that has an air-core section;
`0110 a magnetic sheet that is disposed on a non-transmis
`sion side of the planarair-core coil, a first side of the magnetic
`sheet being placed on the planar air-core coil; and
`0111 a printed circuit board that is disposed on a second
`side of the magnetic sheet,
`0112 the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil, the lead line
`being provided on the non-transmission side; and
`0113 the printed circuit board including a receiving sec
`tion that receives the lead line.
`0114. The coil units according to these embodiments can
`achieve the same effects as the coil unit according to the above
`embodiment of the invention.
`0115 According to another embodiment of the invention,
`there is provided a coil unit comprising:
`0116 a planar air-core coil that has an air-core section;
`0117 a coil-receiving housing that is disposed on a trans
`mission side of the planar air-core coil; and
`0118 a printed circuit board that is disposed on a non
`transmission side of the planar air-core coil,
`0119 the printed circuit board being fixed on the coil
`receiving housing:
`I0120 the planar air-core coil being placed between the
`coil-receiving housing and the printed circuit board;
`I0121
`the planar air-core coil including a lead line con
`nected to an inner end of the planar air-core coil on the
`transmission side; and
`0.122
`the coil-receiving housing including a receiving
`section that receives the lead line.
`I0123. The coil unit according to this embodiment can
`achieve the same effects as the coil unit according to the
`embodiment of the invention in which the receiving section is
`formed in the coil-receiving housing.
`0.124. According to another embodiment of the invention,
`there is provided an electronic instrument comprising one of
`the above coil units.
`0.125
`Preferred embodiments of the invention are
`described in detail below. Note that the embodiments
`described below do not in any way limit the scope of the
`invention defined by the claims laid out herein. Note that all
`elements of the embodiments described below should not
`necessarily be taken as essential requirements for the inven
`tion.
`1. Charging System
`0.126
`I0127 FIGS. 1 and 2 are views schematically showing a
`charging system including a charger 10 and an electronic
`instrument (e.g., portable telephone 20) which is charged
`using the charger 10. FIG. 1 shows a portable telephone 20A
`which is horizontally placed on a charger 10A. The portable
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`telephone 20A is charged using the charger 10A by non
`contact power transmission utilizing electromagnetic induc
`tion which occurs between a coil of a coil unit 12 of the
`charger 10A and a coil of a coil unit 22 of the portable
`telephone 20A.
`0128. The portable telephone 20A is placed on the charger
`10A in a state in which a positioning depression (positioning
`target section in a broad sense) (not shown in FIG. 1) is
`positioned with respect to a positioning protrusion 14 (posi
`tioning section in a broad sense) of the charger 10A. Since the
`portable telephone 20A is placed on the charger 10A while
`positioning the positioning depression with respect to the
`positioning protrusion 14, the portable telephone 20A can be
`placed on the charger 10A at an appropriate position,
`whereby transmission efficiency can be increased.
`0129. The opposite sides of the coil units 12 and 22
`through which the coil units 12 and 22 perform non-contact
`power transmission as shown in FIG. 1 are referred to as
`transmission sides. In FIG. 1, the upper side of the coil unit 12
`is the transmission side, and the lower side of the coil unit 22
`is the transmission side. The side opposite to the transmission
`side is referred to as a non-transmission side.
`0130 2. Structure of Coil Unit
`0131 2.1 Coil Unit in which Coil Inner End Lead Line is
`Provided Over Transmission Side
`0132. The coil units 12 and 22 are described in detail
`below taking the thin coil unit 22 suitable for the portable
`telephone 20 as an example.
`0133 FIG. 2 is an oblique view showing the coil unit 22.
`FIGS. 3A and 3B are cross-sectional views schematically
`showing two types of coil units 22 along the line VII-VII
`shown in FIG. 2. FIGS. 4 and 5 are exploded oblique views
`showing the coil units 22 shown in FIGS. 3A and 3B.
`0134. The coil unit 22 includes a planar air-core coil 30B,
`a magnetic sheet 40B, and a magnetic flux leakage prevention
`member 50 provided in that order on the side of a printed
`circuit board (e.g., flexible circuit board) 60 opposite to the
`side which faces a housing 20a through a double-sided tape
`T0.
`0135. As shown in FIGS. 4 and 5, the planar air-core coil
`30B has a lead line 32 which connects or withdraws the inner
`end of the planar air-core coil 30B over the transmission side.
`A lead line 34 connects or withdraws the outer end of the
`planar air-core coil 30B. Placement sections 60a and 70a
`which receive the lead line 32 are respectively formed (cut) in
`the double-sided tape 70 and the printed circuit board 60
`disposed on the side of the coil on which the lead line 32 is
`provided. The receiving sections 60a and 70a are formed of
`long holes, for example. As shown in FIG. 6, the lead line 32
`is placed in the receiving section 60a when viewed from the
`printed circuit board 60. The lead line 32 does not increase the
`thickness of the coil unit 22 or the degree to which the lead
`line 32 increases the thickness of the coil unit 22 can be
`reduced by placing the lead line 32 in the receiving sections
`60a and 70a.
`0136. As shown in FIGS. 4 and 5, a through-hole 60b is
`formed in the printed circuit board 60 at a position corre
`sponding to an air-core section 31B of the planar air-core coil
`30B. The diameter of the through-hole 60b is set to be smaller
`than the diameter of the air-core section 31B of the planar
`air-core coil 30B. A temperature detection section 80 (e.g.,
`thermistor) is provided on the side of the printed circuit board
`60 which faces the planar air-core coil 30B (example shown
`in FIGS. 3A and 4) or the side of the printed circuit board 60
`
`opposite to the side which faces the planar air-core coil 30B
`(example shown in FIGS. 3B and5) inside the air-core section
`31B. The temperature of a foreign object which enters the
`space between the charger 10 and the portable telephone 20
`can be detected by providing the temperature detection sec
`tion 80 inside the air-core section 31B. In particular, a foreign
`object which is positioned near the air-core section 31B hav
`ing a high magnetic flux density produces a considerable
`amount of heat due to eddy current. The temperature of the
`foreign object can be accurately detected by providing the
`temperature detection section 80.
`0.137 The side surface of the magnetic sheet 40B may be
`covered with the magnetic flux leakage prevention member
`50, as shown in FIGS. 3A and 3B. This prevents corrosion of
`the magnetic sheet 40B or scattering of a magnetic powder
`due to breakage of the magnetic sheet or the like.
`0.138. The magnetic sheet 40B of the portable telephone
`20 may be formed to be larger than the external shape of a
`planar air-core coil 30A of the charger 10. This prevents a
`situation in which a chargeable battery provided in the coil
`unit 22 or a metal of the circuit board undergoes eddy current
`loss, whereby power transmission efficiency can be
`increased.
`0.139
`2.2 Coil Unit in which Coil Inner End Lead Line is
`Provided Over Non-Transmission Side
`0140 FIG. 7 is an exploded oblique view showing a sec
`ond configuration example. This configuration example illus
`trates the case of providing the lead line 32 of the inner end of
`the planar air-core coil 30 on the non-transmission side oppo
`site to the transmission side (housing side).
`0.141. As shown in FIG. 7, the magnetic sheet 40B is
`provided on the non-transmission side (lower side in FIG. 7)
`of the planar air-core coil 30B opposite to the transmission
`side through a double-sided tape 72. A printed circuit board
`64 is provided under the magnetic sheet 40B. Specifically,
`when the side of the magnetic sheet 40B which comes into
`contact with the planar air-core coil 30B is referred to as a first
`side, the printed circuit board 64 comes into contact with a
`second side of the magnetic sheet 40B. A receiving section
`(through-hole or depression) 64a is formed in the printed
`circuit board 64 at a position corresponding to the lead line
`32. The thickness of the lead line 32 can be absorbed by the
`receiving section 64a through deformation of the magnetic
`sheet 40B by forming the receiving section 64a.
`0142. According to the structure shown in FIG.7, since the
`planar air-core coil 30 is disposed so that the transmission
`side of the planar air-core coil 30 faces the inner surface of the
`housing of the portable telephone 20, the distance between
`the primary coil unit 12 and the secondary coil unit 22 is
`reduced as compared with the above example so that trans
`mission efficiency may be increased. Moreover, the planar
`air-core coil 30 can be positioned with respect to the housing
`by placing a positioning protrusion which protrudes from the
`inner surface of the housing of the portable telephone 20 in
`the air-core section of the planar air-core coil 30. In this case,
`it is unnecessary to form a positioning through-hole in the
`printed circuit board 64.
`0.143
`2.3 Coil Unit having Coil-Receiving Housing
`014.4 FIGS. 8 and 9 are exploded oblique views showing
`a coil unit which includes part of the housing 20a of the
`portable telephone 20 shown in FIG. 1 as a coil-receiving
`housing at different angles. The coil-receiving housing forms
`part of the external housing of the charger 10 or the electronic
`instrument 20. The outer surface of the external housing is
`
`Scramoge Technology Ltd.
`Ex. 2020 - Page 17
`
`

`

`US 2008/0.197957 A1
`
`Aug. 21, 2008
`
`flush with the outer surface of the coil-receiving housing. This
`configuration example shown in FIGS. 8 and 9 illustrates the
`case of providing the lead line32 of the inner end of the planar
`air-core coil 30 on the transmission side (housing side). Note
`that the lead line32 of the inner end of the planar air-core coil
`30 may be provided on the non-transmission side (magnetic
`sheet side).
`0145 As shown in FIGS. 8 and 9, the planar air-core coil
`30B, the magnetic sheet 40B, and a one-sided tape 74 are
`provided between the coil-receiving housing 20a and a
`printed circuit board 66. In this embodiment, the magnetic
`sheet 40b is not an indispensable element. The coil-receiving
`housing 20a has a receiving section 20b which receives the
`lead line 32 of the inner end of the planar air-core coil 30B,
`and a receiving section 20c which receives the lead line 34 of
`the outer end of the planar air-core coil 30B. The lead line 32
`of the inner end of the coil is pulled out to the side opposite to
`the transmission side and is connected to the printed circuit
`board 66.
`0146 FIGS. 10 to 13 are views schematically showing a
`process of manufacturing the coil unit. As shown in FIG. 10,
`the planar air-core coil 30B is placed inside a ring-shaped rib
`20d of the coil-receiving housing 20a. The planar air-core coil
`30B is positioned utilizing a positioning protrusion 28 pro
`vided on the coil-receiving housing 20a. As shown in FIG. 11,
`the magnetic sheet 40B is attached to the planar air-core coil
`30B so that the magnetic sheet 40B is positioned over the
`planar air-core coil 30B. As shown in FIG. 12, the magnetic
`sheet 40B is covered with the one-sided tape 74 so that a soft
`magnetic metal powder does not fall onto the printed circuit
`board provided under the magnetic sheet 40B from the outer
`edge of the magnetic sheet 40B. As shown in FIG. 13, the
`printed circuit board 66 is attached. The receiving sections
`20b and 20c formed in the housing 20a are sealed with an
`adhesive or a molding material in order to prevent the material
`(Soft magnetic metal powder) for the magnetic sheet from
`leaking through the receiving sections 20b and 20c.
`0147 According to this structure, a situation in which the
`coil is unwound or deformed during transportation or incor
`poration of the coil can be prevented as compared with the
`coil unit shown in FIGS. 2 to 7, whereby deformation of the
`coil which may adversely affect electrical properties such as
`inductance can be prevented.
`0148. The structures shown in FIGS. 2 to 13 may also be
`applied to the coil unit 12 of the charger 10.
`Application Example of Electronic Instrument
`01