WO2017047498A1 - Flexible printed wiring board and contactless charging system - Google Patents

Abstract

This flexible printed wiring board has an insulation film and an electroconductive pattern laminated on at least one surface side of the insulation film, wherein the flexible printed wiring board has an annular coil region in which the electroconductive pattern constitutes a coil-shaped circuit, and a component region provided on the outside of the coil region, the component region having an electronic component electrically connected to the electroconductive pattern of the coil region. In addition, in this contactless charging system, each of a power supply module and a power reception module is provided with the flexible printed wiring board, and the contactless charging system is configured so that during charging, the coil region of the flexible printed wiring board of the power supply module and the coil region of the flexible printed wiring board of the power reception module face each other.

Description

Flexible printed wiring board and non-contact charging system

The present invention relates to a flexible printed wiring board and a contactless charging system.
This application claims priority based on Japanese Patent Application No. 2015-185733 filed on Sep. 18, 2015, and incorporates all the content described in the above Japanese application.

Conventionally, a non-contact charging system using an electromagnetic induction phenomenon is known. In this charging system, a power receiving module (secondary coil) is arranged at a position facing the power feeding module (primary coil), and a current is generated in the power receiving module by magnetic flux generated by passing a current through the power feeding module. . As a coil used in this charging system, for example, a planar coil in which a conductive wire is wound concentrically on the surface of a magnetic sheet is known (see JP 2013-169122 A).

In recent years, such a charging system is becoming widespread as a charging device for portable devices, and a wearable device such as a wristwatch type or a ring type has been developed as the portable device in addition to a conventional cellular phone. Since such a wearable device is small, the charging system mounted on the wearable device is also required to be small.

JP 2013-169122 A

The flexible printed wiring board which concerns on 1 aspect of this invention is a flexible printed wiring board which has an insulating film and the conductive pattern laminated | stacked on the at least one surface side of this insulating film, Comprising: A conductive pattern has a coil-shaped circuit. And a component region having an electronic component that is disposed outside the coil region and electrically connected to the conductive pattern of the coil region.

FIG. 1A is a schematic side view illustrating a charging device to which a power supply module of a contactless charging system according to one aspect of the present invention is attached. FIG. 1B is a schematic plan view showing the charging device of FIG. 1A. FIG. 2A is a schematic side view showing a wearable device to which a power receiving module of the non-contact charging system according to one aspect of the present invention is attached. FIG. 2B is a schematic plan view showing the wearable device of FIG. 2A. FIG. 3 is a schematic side view showing a state when the wearable device of FIG. 2A is charged by the charging device of FIG. 1A. FIG. 4A is a schematic plan view illustrating a coil region of the flexible printed wiring board of the power supply module of the non-contact charging system according to one aspect of the present invention. 4B is a schematic cross-sectional view taken along line AA in FIG. 4A. FIG. 5 is a schematic plan view illustrating a flexible printed wiring board of the power receiving module of the non-contact charging system according to one aspect of the present invention. FIG. 6 is a schematic partial cross-sectional view showing a flexible printed wiring board having a mode different from that in FIG. 4B.

[Problems to be solved by the present disclosure]
Since the conventional planar coil used for the power supply module and the power receiving module is configured using a magnetic sheet and a conductive wire, it is hard and difficult to arrange along the curved surface. For this reason, it is difficult to store the conventional planar coil in a wearable device having a curved surface, for example, a donut-shaped or circular wearable device, which is a limitation on downsizing of the charging system. Moreover, since the conducting wire has a large wire diameter, it is difficult to reduce the size of the planar coil itself. Therefore, it is difficult for a conventional charging system using a planar coil to meet the demand for downsizing wearable devices.

The present invention has been made based on the above-described circumstances, and an object thereof is to provide a flexible printed wiring board and a non-contact charging system that can be applied to a small wearable device.

[Effects of the present disclosure]
The flexible printed wiring board of the present invention can promote downsizing of a non-contact charging system and can be easily applied to a wearable device or the like.

[Description of Embodiment of the Present Invention]
The flexible printed wiring board which concerns on 1 aspect of this invention is a flexible printed wiring board which has an insulating film and the conductive pattern laminated | stacked on the at least one surface side of this insulating film, Comprising: A conductive pattern has a coil-shaped circuit. And a component region having an electronic component that is disposed outside the coil region and electrically connected to the conductive pattern of the coil region.

The flexible printed wiring board can be thinned and miniaturized, and can be arranged on a curved surface by bending, so that the power supply module and the power receiving module of the non-contact charging system can be easily downsized. Therefore, the flexible printed wiring board can be easily applied to wearable devices. Further, in the flexible printed wiring board, since the coil area is annular, the central space becomes a path for the magnetic field, and the inductance can be increased with respect to the circuit length and the conductor area of the coil.

The coiled circuit of the flexible printed wiring board of the power feeding module or the coiled circuit of the flexible printed wiring board of the power receiving module may be formed of a spiral conductive pattern. In this way, by configuring the coiled circuit of the power supply module or the power receiving module with a spiral conductive pattern, the inductance can be easily set to a desired value by adjusting the average width, average thickness, and number of turns of the conductive pattern.

The coil region is laminated on one surface side of the insulating film to form a first coiled circuit, and the second coil shape is laminated on the surface side opposite to the first conductive pattern of the insulating film. It is preferable that the first conductive pattern and the second conductive pattern are electrically connected through a through hole. Thus, by providing a coil area | region on both surfaces of an insulating film, an inductance can be further enlarged, suppressing the increase in the magnitude | size of a flexible printed wiring board.

It is good to further have two or more conductive patterns which are arranged via an insulating film and have at least an annular coil region constituting a coiled circuit, and the conductive patterns are electrically connected by a through hole. . By setting it as such a structure, an inductance can be enlarged further, suppressing the increase in the magnitude | size of a flexible printed wiring board.

It is preferable to further have a magnetic layer containing a ferromagnetic material on the surface of the insulating film opposite to the coil region. Thus, when the said insulating film further has a magnetic body layer, a magnetic body can absorb a magnetic flux and can enlarge the inductance of a coil-shaped circuit.

The present invention is a non-contact charging system comprising a power supply module attached to a charging device and a power receiving module attached to an annular wearable device, wherein each of the power supply module and the power receiving module includes the flexible printed wiring board. And a non-contact charging system configured such that a coil region of the flexible printed wiring board of the power supply module and a coil region of the flexible printed wiring board of the power receiving module face each other during charging.

The contactless charging system includes the flexible printed wiring board in which the power supply module and the power receiving module have a coil region. Since the flexible printed wiring board can be thinned and miniaturized and can be arranged on a curved surface by bending, the contactless charging system can easily reduce the size of the power supply module and the power reception module. Therefore, the contactless charging system can be easily applied to a wearable device.

The charging device may include a pedestal portion on which the power supply module is disposed, and a columnar convex portion that is provided in a state of protruding from the upper surface of the pedestal portion and into which the wearable device can be fitted. By using the charging device and the wearable device having such a shape, the power feeding module and the power receiving module can be easily opposed and separated during charging.

[Details of the embodiment of the present invention]
Hereinafter, an embodiment of a flexible printed wiring board and a non-contact charging system according to the present invention will be described in detail with reference to the drawings.

The contactless charging system shown in FIGS. 1A, 1B, 2A, 2B, and 3 includes a power supply module 10 attached to the charging device 1 and a power receiving module 20 attached to the annular wearable device 2. .

<Charging device>
The charging device 1 is provided with a pedestal portion 11 on which the power supply module 10 is disposed, and a columnar convex portion 12 provided on the upper surface of the pedestal portion 11 to which the wearable device 2 can be fitted. Is provided. The wearable device 2 is charged by fitting the through hole 21 of the wearable device 2 to the convex portion 12 of the charging device 1.

(Pedestal)
The pedestal portion 11 is a flat plate with a constant thickness having a space inside, and is provided in a state where the convex portion 12 protrudes from the upper surface thereof. The planar shape of the pedestal portion 11 is circular, and the diameter thereof is larger than the diameter of the bottom surface of the convex portion 12. Moreover, the upper surface of the base part 11 may be chamfered. By chamfering the upper surface in this way, it is possible to prevent the bottom surface of the wearable device 2 from inadvertently hitting the pedestal portion 11 when being fitted to the wearable device 2 described later. Moreover, even if a user's hand etc. contact the charging device 1, it is hard to generate | occur | produce an injury to a user.

The material of the pedestal portion 11 is not particularly limited as long as it has an insulating property and does not have magnetism. For example, a plate material mainly composed of a resin can be used. Moreover, the base part 11 may contain components other than resin as long as electroconductivity and magnetism are not provided. The “main component” refers to a component that is contained, for example, by 50% by mass or more.

The size of the pedestal 11 is not particularly limited and can be appropriately designed according to the size of the wearable device 2 to be charged. The diameter of the upper surface of the pedestal 11 may be a size that can support the wearable device 2 when the wearable device 2 is fitted, and may be, for example, 18 mm or more and 340 mm or less. Moreover, the height (average thickness) of the base part 11 can be 5 mm or more and 30 mm or less, for example.

(Convex)
The convex portion 12 has a cylindrical shape, and the upper surface thereof may be chamfered for the same reason as the pedestal portion 11.

The material of the convex portion 12 can be the same as that of the pedestal portion 11. Further, the convex portion 12 may be integrally formed with the pedestal portion 11.

The magnitude | size of the convex part 12 is not specifically limited, It can design suitably according to the magnitude | size of the wearable device 2 to be charged. The average diameter of the convex part 12 can be 10 mm or more and 200 mm or less, for example.

Moreover, the height (axial direction length) of the convex part 12 can be 10 mm or more and 50 mm or less, for example. Although the convex part 12 may be tapered, it is preferable that the convex part 12 is not tapered in view of ease of fitting with the wearable device 2. The lower limit of the ratio of the height of the convex portion 12 to the height of the wearable device 2 is preferably 0.4 times, more preferably 0.6 times, and even more preferably 0.9 times. On the other hand, the upper limit of the ratio of the height of the convex portion 12 to the height of the wearable device 2 is preferably 1.5 times, more preferably 1.2 times, and even more preferably 1.1 times. When the ratio of the height of the convex portion 12 to the height of the wearable device 2 is less than the above lower limit, the ratio of the fitting portion with respect to the height of the wearable device 2 during charging is reduced. The device 2 may be easily detached. On the contrary, when the ratio of the convex portion 12 to the height of the wearable device 2 exceeds the upper limit, the wearable device 2 may be difficult to remove from the charging device 1 or the user may be injured by the protruding portion. In particular, when the ratio of the convex portion 12 to the height of the wearable device 2 is 0.9 times or more and 1.1 times or less, a visual effect that makes the charging device 1 appear small can be easily obtained.

Further, the central axis of the convex portion 12 is preferably substantially coincident with the axis in the thickness direction passing through the center of gravity of the upper surface of the pedestal portion 11. Thus, by making the central axis of the convex part 12 and the axis of the pedestal part 11 substantially coincide with each other, the upper surface of the pedestal part 11 that supports the wearable device 2 when the wearable device 2 is fitted is around the convex part 12. Are arranged relatively evenly. For this reason, the posture of the fitted wearable device 2 is easily stabilized. Note that “the axes substantially coincide with each other” means that the two axes are substantially parallel and the distance between the two axes is 5% or less of the diameter of each bottom surface.

<Power supply module>
The power supply module 10 is attached to the charging device 1. A method for attaching the power supply module 10 to the charging device 1 is not particularly limited. For example, a method in which the bottom surface of the pedestal part 11 is formed of a hollow structure made of another plate material, the power supply module 10 is attached to the upper surface of the other plate material, and the plate material is fixed to the pedestal portion 11 with an adhesive, a screw, or the like. In addition, a method of embedding the power supply module 10 when the pedestal portion 11 is molded can be exemplified.

The power supply module 10 includes a flexible printed wiring board 30 as shown in FIGS. 4A and 4B, and generates a magnetic flux in the central axis direction of the coil by supplying current from a component region (not shown) of the flexible printed wiring board 30. . Since the coil-like circuit 32a of the flexible printed wiring board 30 to be described later is disposed substantially parallel to the bottom surface of the convex portion 12, the magnetic flux generated by the power supply module 10 is substantially parallel to the central axis of the convex portion 12. Become.

In the component region, for example, an electronic component (current supply circuit) for supplying current to the power supply module 10 is mounted and connected to the coil region X by a conductive pattern. The power supply of this current supply circuit can be arbitrarily selected, and may be an AC power supply or a DC power supply. In addition to a household power source, a primary battery, a secondary battery, a solar battery, or the like can be used as a power source. This component region can be disposed inside the pedestal 11 and the convex 12.

<Flexible printed wiring board>
The flexible printed wiring board 30 includes an insulating film 31 and a conductive pattern 32 laminated on one surface side (front surface side) of the insulating film 31. In addition, the flexible printed wiring board 30 has an annular coil region X in which the conductive pattern 32 forms a coiled circuit 32a. The flexible printed wiring board 30 has a magnetic layer 33 containing a ferromagnetic material on the surface side (back side) opposite to the coil region X of the insulating film 31, and the magnetic layer 33 is bonded to the magnetic material. It is adhered to the insulating film 31 through the layer 34. Further, the flexible printed wiring board 30 has a cover lay 35 on the surface side.

(Insulating film)
The insulating film 31 is a base film (base material) for forming the coiled circuit 32a. The planar shape of the insulating film 31 is annular.

The main component of the insulating film 31 is a resin. The resin used for the insulating film 31 is not particularly limited as long as it has insulating properties, but a resin film formed in a sheet shape having flexibility and electrical insulating properties can be employed. Examples of the material for the resin film include polyimide, polyethylene terephthalate, polyethylene naphthalate, liquid crystal polymer, and fluororesin.

The lower limit of the average thickness of the insulating film 31 is preferably 5 μm and more preferably 10 μm. On the other hand, the upper limit of the average thickness of the insulating film 31 is preferably 50 μm, and more preferably 40 μm. When the average thickness of the insulating film 31 is less than the lower limit, the insulating resistance of the insulating film 31 may be insufficient. Conversely, when the average thickness of the insulating film 31 exceeds the upper limit, the flexible printed wiring board 30 may be unnecessarily thick.

The inner diameter (inner diameter) of the coil region X of the insulating film 31 is larger than the diameter of the through hole 21 of the wearable device 2. Specifically, the lower limit of the inner diameter of the insulating film 31 is preferably 15 mm, and more preferably 22 mm. On the other hand, the upper limit of the inner diameter of the insulating film 31 is preferably 200 mm, and more preferably 185 mm. When the inner diameter of the insulating film 31 is less than the lower limit, there is a possibility that it cannot be stored inside the power supply module 10 or the like. Conversely, even when the inner diameter of the insulating film 31 exceeds the upper limit, there is a possibility that it cannot be stored inside the power supply module 10 or the like.

The lower limit of the difference between the outer diameter (outer diameter) and inner diameter of the coil region X of the insulating film 31 (the width of the coil region X of the insulating film 31) is preferably 1 mm, and more preferably 2 mm. On the other hand, the upper limit of the width of the coil region X of the insulating film 31 is preferably 5 mm, and more preferably 4 mm. When the width of the coil region X of the insulating film 31 is less than the lower limit, an area where the coiled circuit 32a can be stacked is insufficient, so that a desired inductance may not be obtained. On the other hand, when the width of the coil region X of the insulating film 31 exceeds the upper limit, there is a risk that the requirement for downsizing of the device is violated.

(Coil area)
The coil region X has an annular shape, and the conductive pattern 32 forms a coiled circuit 32a.

The material of the conductive pattern 32 is not particularly limited as long as it has conductivity, but a material having a small electric resistance is preferable. For example, the conductive pattern 32 can be formed of copper. The surface of the conductive pattern 32 may be plated with gold, silver, tin or the like. The conductive pattern 32 can also be formed by a printing method using a conductive paste such as a silver paste or a copper paste.

The lower limit of the average thickness of the conductive pattern 32 is preferably 0.1 μm, and more preferably 1 μm. On the other hand, the upper limit of the average thickness of the conductive pattern 32 is preferably 100 μm, and more preferably 80 μm. When the average thickness of the conductive pattern 32 is less than the above lower limit, the internal resistance may increase and the loss may be excessive, and the strength may be insufficient to easily break the coiled circuit 32a. Conversely, when the average thickness of the conductive pattern 32 exceeds the upper limit, the flexible printed wiring board 30 may become unnecessarily thick.

The coiled circuit 32a is composed of a spiral conductive pattern. By configuring the coiled circuit 32a with a spiral conductive pattern in this way, the inductance can be easily set to a desired value by adjusting the average width, average thickness, and number of turns of the conductive pattern.

The coiled circuit 32a has connection terminals at both ends. By supplying a current from the current supply circuit to the connection terminal, a magnetic flux can be generated in the coiled circuit 32a.

The lower limit of the average width of the conductor forming the coiled circuit 32a is preferably 10 μm, and more preferably 100 μm. On the other hand, the upper limit of the average width of the conductor forming the coiled circuit 32a is preferably 1000 μm, and more preferably 500 μm. When the average width of the conductor forming the coiled circuit 32a is less than the lower limit, the mechanical strength of the coiled circuit 32a is insufficient, and there is a risk of breakage. On the other hand, when the average width of the conductor forming the coiled circuit 32a exceeds the above upper limit, a sufficient number of turns cannot be secured, and a desired inductance may not be obtained. In addition, although it does not specifically limit as a conductor pitch of the conductor which forms the coil-shaped circuit 32a, For example, they are 3 micrometers or more and 10 micrometers or less.

The lower limit of the number of turns of the coiled circuit 32a is preferably 5, and more preferably 10. On the other hand, the upper limit of the number of turns of the coiled circuit 32a is preferably 100, and more preferably 90. When the number of turns of the coiled circuit 32a is less than the lower limit, the electromotive force induced in the coiled circuit 32a may be insufficient. On the other hand, when the number of turns of the coiled circuit 32a exceeds the upper limit, it is necessary to reduce the conductor width of the coiled circuit 32a in order to dispose the coiled circuit 32a in the limited space of the insulating film 31, and the resistance of the coiled circuit 32a. May become unnecessarily large.

(Magnetic layer)
The magnetic layer 33 is laminated on the back surface side of the insulating film 31 via the magnetic adhesive layer 34. The magnetic layer 33 includes a ferromagnetic material.

The magnetic layer 33 supplements and blocks the magnetic flux formed by the coiled circuit 32a. The magnetic layer 33 may be any layer that can efficiently supplement magnetic flux by including a ferromagnetic material. The magnetic layer 33 is preferably flexible, and for example, a magnetic sheet having magnetic powder and its binder can be used. As said magnetic powder, a well-known thing can be used as a magnetic material which comprises magnetic sheets, such as magnetic stainless steel, Sendust, permalloy, silicon copper, and a ferrite. Among them, ferrite with low eddy current loss in a high frequency band is preferable, and manganese zinc, nickel zinc, copper zinc, and rare earth iron garnet ferrite are particularly preferable.

The lower limit of the relative permeability of the magnetic layer 33 is preferably 20, and more preferably 30. On the other hand, the upper limit of the relative permeability of the magnetic layer 33 is preferably 500, and more preferably 300. When the relative permeability of the magnetic layer 33 is less than the lower limit, a desired inductance may not be obtained due to a decrease in coupling of magnetic flux of the coiled circuit 32a. On the other hand, when the relative permeability of the magnetic layer 33 exceeds the upper limit, the DC resistance of the coiled circuit 32a increases, and the transmission performance of the contactless charging system may be reduced. In addition, the magnetic layer 33 becomes overspec, and the contactless charging system may be expensive.

The lower limit of the average thickness of the magnetic layer 33 is preferably 10 μm, and more preferably 20 μm. On the other hand, the upper limit of the average thickness of the magnetic layer 33 is preferably 500 μm, and more preferably 300 μm. When the average thickness of the magnetic layer 33 is less than the lower limit, the magnetic flux formed by the coiled circuit 32a cannot be sufficiently blocked, and the surrounding metal may be heated by the leakage magnetic flux. On the contrary, when the average thickness of the magnetic layer 33 exceeds the upper limit, the flexible printed wiring board 30 may be unnecessarily thick and difficult to bend.

The material of the adhesive forming the magnetic adhesive layer 34 that adheres the magnetic layer 33 to the insulating film 31 is not particularly limited, but is preferably excellent in flexibility and heat resistance. Examples of the adhesive include resin-based adhesives such as epoxy resin, polyimide, polyester, phenol resin, polyurethane, acrylic resin, melamine resin, and polyamideimide. A bonding sheet obtained by molding these adhesives on a film can be suitably used as the magnetic adhesive layer 34.

The lower limit of the average thickness of the magnetic adhesive layer 34 is preferably 5 μm and more preferably 10 μm. On the other hand, the upper limit of the average thickness of the magnetic adhesive layer 34 is preferably 50 μm and more preferably 40 μm. When the average thickness of the magnetic adhesive layer 34 is less than the above lower limit, the adhesive strength between the insulating film 31 and the magnetic layer 33 becomes insufficient, and there is a possibility that it is difficult to make close contact with the cover lay 35 of the flexible printed wiring board 30. Conversely, when the average thickness of the magnetic adhesive layer 34 exceeds the upper limit, the flexible printed wiring board 30 may be unnecessarily thick.

(Coverlay)
The coverlay 35 mainly protects the conductive pattern 32. The cover lay 35 has a cover film 35a and a cover film adhesive layer 35b.

The cover film 35a has flexibility and insulation. Examples of the main component of the cover film 35a include polyimide, epoxy resin, phenol resin, acrylic resin, polyester, thermoplastic polyimide, polyethylene terephthalate, polyethylene naphthalate, fluororesin, and liquid crystal polymer. In particular, polyimide is preferable from the viewpoint of heat resistance. The cover film 35a may contain a resin other than the main component, a weathering agent, an antistatic agent, and the like.

The lower limit of the average thickness of the cover film 35a is not particularly limited, but is preferably 3 μm and more preferably 10 μm. Moreover, as an upper limit of the average thickness of the cover film 35a, although it does not specifically limit, 500 micrometers is preferable and 150 micrometers is more preferable. When the average thickness of the cover film 35a is less than the lower limit, the conductive pattern 32 may not be sufficiently protected, and when the cover film 35a is required to have insulating properties, the insulating properties may be insufficient. There is. On the other hand, when the average thickness of the cover film 35a exceeds the above upper limit, the protective effect of the conductive pattern 32 may be reduced, and the flexibility of the cover film 35a may be insufficient.

Although it does not specifically limit as an adhesive agent which comprises the cover film adhesive layer 35b, The thing excellent in the softness | flexibility and heat resistance is preferable. Examples of the adhesive include various resin adhesives such as epoxy resin, polyimide, polyester, phenol resin, polyurethane, acrylic resin, melamine resin, and polyamideimide.

The lower limit of the average thickness of the cover film adhesive layer 35b is preferably 5 μm, and more preferably 10 μm. Moreover, as an upper limit of the average thickness of the cover film contact bonding layer 35b, 50 micrometers is preferable and 40 micrometers is more preferable. When the average thickness of the cover film adhesive layer 35b is less than the above lower limit, the adhesive strength of the cover lay 35 to the conductive pattern 32 may be insufficient. On the other hand, when the average thickness of the cover film adhesive layer 35b exceeds the upper limit, the flexible printed wiring board 30 may be unnecessarily thick.

The power supply module 10 is disposed inside the pedestal portion 11 so that the surface of the insulating film 31 is substantially parallel to the bottom surface of the convex portion 12 during charging. In addition, the power supply module 10 may be arranged so that the coiled circuit 32a is closer to the surface of the power receiving module 20 that is closer to the flexible printed wiring board 40 than the insulating film 31 during charging. By disposing the power supply module 10 in this way, the insulating film 31 does not become a shield between the power supply module 10 and the power reception module 20 during power transmission, and a decrease in power transmission efficiency can be suppressed.

The lower limit of the average distance between the surface of the flexible printed wiring board 30 of the power supply module 10 and the upper surface of the pedestal 11 is preferably 0.5 mm, and more preferably 1 mm. On the other hand, the upper limit of the average distance between the surface of the flexible printed wiring board 30 and the upper surface of the pedestal 11 is preferably 5 mm, and more preferably 3 mm. When the average distance between the surface of the flexible printed wiring board 30 and the upper surface of the pedestal portion 11 is less than the lower limit, the thickness of the pedestal portion 11 that covers the power supply module 10 becomes too thin. There is a risk. Conversely, when the average distance between the surface of the flexible printed wiring board 30 and the upper surface of the pedestal 11 exceeds the upper limit, the power transmission efficiency from the power supply module 10 to the power reception module 20 may be reduced, or power transmission may not be possible. There is a fear.

<Wearable device>
The wearable device 2 has a hollow cylindrical shape, and a part thereof protrudes radially outward. Moreover, the wearable device 2 has an inner wall that fits into the convex portion 12 of the charging device 1. Specifically, the wearable device 2 has a ring shape having a through hole 21 in the center.

Further, the upper surface and the lower surface of the wearable device 2 may be chamfered for the same reason as the convex portion 12 of the charging device 1.

The thickness in the radial direction excluding the protruding portion of the wearable device 2 is preferably substantially constant. In this way, by making the thickness in the radial direction excluding the protruding portion of the wearable device 2 substantially constant, the surface on which the wearable device 2 is supported by the charging device 1 during charging is compared with the periphery of the convex portion 12 of the charging device 1. Evenly arranged. For this reason, the posture of the fitted wearable device 2 is easily stabilized. Note that “substantially constant” means that the difference from the average is 5% or less.

The material of the wearable device 2 can be the same as that of the convex portion 12.

The height (axial length) of the wearable device 2 is appropriately designed according to its function and purpose, and can be, for example, 6 mm or more and 50 mm or less.

The diameter of the through hole 21 is larger than the diameter of the convex portion 12 of the charging device 1. As a minimum of the difference of the diameter of the said through-hole 21, and the diameter of the convex part 12 of the charging device 1, 0.5 mm is preferable and 1 mm is more preferable. On the other hand, the upper limit of the diameter difference between the through hole 21 and the convex portion 12 is preferably 2 mm, and more preferably 1.5 mm. When the difference in diameter between the through hole 21 and the convex portion 12 is less than the lower limit, it may be difficult to fit and remove the charging device 1 and the wearable device 2. On the contrary, when the diameter difference between the through hole 21 and the convex portion 12 exceeds the upper limit, the play when the charging device 1 and the wearable device 2 are fitted is too large, and a power supply module 10 and a power receiving module 20 described later. There is a risk that the power is not transmitted sufficiently due to a deviation in the position opposite to.

<Power receiving module>
The power receiving module 20 is provided inside the wearable device 2 and includes a flexible printed wiring board 40 as shown in FIG.

The method for attaching the power receiving module 20 is not particularly limited. For example, a method in which the wearable device 2 has a hollow structure that forms a bottom surface from another plate material, a power receiving module 20 is attached to the top surface of the other plate material, and the plate material is fixed to the wearable device 2 with an adhesive, a screw, or the like. In addition, a method of embedding the power receiving module 20 when the wearable device 2 is molded can be exemplified.

<Flexible printed wiring board>
The flexible printed wiring board 40 has a coil region X in which the coiled circuit 32a is configured. Further, the flexible printed wiring board 40 has a region (component region Y) that constitutes a circuit in which the conductive pattern controls power reception. Furthermore, the flexible printed wiring board 40 has a connection region Z that connects the coil region X and the component region Y. In FIG. 5, the same components as those of the flexible printed wiring board 30 of the power supply module 10 are denoted by the same reference numerals, and the description thereof is omitted.

(Coil area)
The coil area X can be configured similarly to the coil area X of the flexible printed wiring board 30 of the power supply module 10. From the viewpoint of power transmission efficiency, the power supply module 10 and the power reception module 20 may include a flexible printed wiring board having a coil region X having the same shape.

The average width, the inter-conductor pitch, and the number of turns of the conductors of the coiled circuit 32a of the flexible printed wiring board 30 of the power supply module 10 and the coiled circuit 32a of the flexible printed wiring board 40 of the power receiving module 20 are as follows. The inductance of 20 may be adjusted so that the resonance frequency and current have desired values. That is, the average width, the inter-conductor pitch, and the number of turns of the conductors of the coiled circuit 32a may be different between the power feeding module 10 and the power receiving module 20.

(Parts area)
In the component area Y, an electronic component for controlling power reception is mounted, and the electronic component is connected by a conductive pattern.

The electronic component is a component that functions electrically, and includes, for example, a connector, a resistor, a capacitor, a sensor, an IC (Integrated Circuit), and the like. In particular, in order to further reduce the size of the product, it is preferable to incorporate a control circuit such as an IC that performs power control or the like in the component region Y as an electronic component.

The part area Y is disposed on the protruding part of the wearable device 2. By arranging the component region Y in the protruding portion that is not curved in this way, it is not necessary to bend the electronic component in the component region Y, so flexibility is not required for the electronic component. And can. For this reason, it is possible to suppress an increase in design constraints on the parts and the like in the part area Y.

(Connection area)
The connection region Z is a region that is connected to the coil region X and the component region Y, and the conductive pattern electrically connects the circuits of the coil region X and the component region Y.

The coil region X, the component region Y, and the connection region Z may be provided on one flexible printed wiring board, but different flexible printed wiring boards may be used for each region. In the case of a single flexible printed wiring board, the coil region X, the component region Y, and the connection region Z can be formed by three-dimensional bending of the flexible printed wiring board. Moreover, when each area | region is comprised with a different flexible printed wiring board, a well-known method can be used as a connection method between flexible printed wiring boards. Examples of such known methods include bump connection, firing of metal paste, pressure bonding using an anisotropic conductive film, welding of conductors, and the like.

The power receiving module 20 is disposed inside the wearable device 2 so as to surround the through hole 21 and so that the surface of the insulating film of the flexible printed wiring board 40 is substantially parallel to the bottom surface of the wearable device 2. In addition, the power receiving module 20 may be arranged such that the coiled circuit 32a is closer to the surface of the power supply module 10 closer to the flexible printed wiring board 40 than the insulating film 31 during charging. By disposing the power receiving module 20 in this way, the insulating film does not become a shield between the power supply module 10 and the power receiving module 20 during power transmission, and a decrease in power transmission efficiency can be suppressed.

The lower limit of the average distance between the surface of the flexible printed wiring board 40 of the power receiving module 20 and the bottom surface of the wearable device 2 is preferably 0.5 mm, and more preferably 1 mm. On the other hand, the upper limit of the average distance between the surface of the flexible printed wiring board 40 and the bottom surface of the wearable device 2 is preferably 5 mm, and more preferably 3 mm. When the average distance between the surface of the flexible printed wiring board 40 and the bottom surface of the wearable device 2 is less than the lower limit, the wearable device 2 covering the power receiving module 20 becomes too thin, and the wearable device 2 is insufficient in strength. There is a risk. Conversely, when the average distance between the surface of the flexible printed wiring board 40 and the bottom surface of the wearable device 2 exceeds the upper limit, the power transmission efficiency from the power supply module 10 to the power reception module 20 may be reduced.

The coil region X of the flexible printed wiring board 30 of the power supply module 10 and the coil region X of the flexible printed wiring board 40 of the power receiving module 20 are configured to face each other during charging. Therefore, the coiled circuit 32a of the power receiving module 20 can generate a current by receiving the magnetic flux generated by the coiled circuit 32a of the power supply module 10 during charging. The generated current is used as power of the wearable device 2 in which the power receiving module 20 is mounted by the power receiving control circuit.

When charging, the surface of the flexible printed wiring board 40 of the power receiving module 20 may be substantially perpendicular to the central axis of the convex portion 12. Thus, the power receiving module 20 can efficiently receive the magnetic flux generated by the power feeding module 10 by making the surface of the flexible printed wiring board 40 of the power receiving module 20 substantially perpendicular to the central axis of the convex portion 12 during charging. Power transmission efficiency is increased. Here, “the surface of the flexible printed wiring board is substantially perpendicular to the central axis of the convex portion” means that the angle formed by the surface of the flexible printed wiring board and the central axis of the convex portion is 90 ° ± 5 °. To do.

Further, from the viewpoint of power transmission efficiency, the average distance between the coil area X of the flexible printed wiring board 30 of the power supply module 10 and the coil area X of the flexible printed wiring board 40 of the power receiving module 20 during charging is preferably small. Specifically, the upper limit of the average distance between the coil regions during charging is preferably 10 mm, and more preferably 6 mm. On the other hand, the lower limit of the average distance between the coil regions during charging is preferably 1 mm and more preferably 2 mm. When the average distance between the coil regions during charging is less than the lower limit, the thickness of the pedestal 11 where the charging device 1 covers the power supply module 10 or the wearable device 2 where the wearable device 2 covers the power receiving module 20 becomes too thin. Therefore, the charging device 1 and the wearable device 2 may be insufficient in strength. Here, the “average distance between coil regions” is the distance in the central axis direction of one coil region between the center point of one coil region and the center point of the other coil region.

The lower limit of the ratio of the projected area of the coil area X of the power supply module 10 to the coil area X of the power receiving module 20 during charging is preferably 90%, and more preferably 95%. When the ratio of the projected area is less than the lower limit, power transmission efficiency may be reduced. Here, the “ratio of the projected area of the coil area of the power feeding module to the coil area of the power receiving module” is the ratio of the area of the projected area of the power feeding module that overlaps the coil area of the power receiving module to the coil area of the power receiving module. .

<Method for producing flexible printed wiring board>
The flexible printed wiring boards 30 and 40 can be easily and reliably manufactured by a manufacturing method including a conductive pattern forming process, a coverlay stacking process, and a magnetic layer stacking process.

(Conductive pattern formation process)
First, in the conductive pattern forming process, a conductive material is laminated on the insulating film 31 to form a conductive pattern 32. The planar shape of the coiled circuit 32a of the conductive pattern 32 can be formed by an appropriate method according to the method of laminating the conductive material. For example, the coiled circuit 32a can be formed by masking and etching a metal film laminated on the insulating film 31. As a method for forming the metal film, for example, a metal foil or the like may be attached to the insulating film 31 with an adhesive or the like, or a metal may be deposited on the insulating film 31 to form the metal film. When the conductive pattern 32 is formed of a conductive paste, the coiled circuit 32a can be formed by a printing technique.

(Coverlay lamination process)
Next, in the cover lay stacking step, the cover lay 35 is stacked on the surface of the conductive pattern 32. Specifically, the coverlay 35 can be formed by attaching the cover film 35a to the conductive pattern 32 via the cover film adhesive layer 35b.

(Magnetic layer lamination process)
Finally, in the magnetic layer stacking step, the magnetic layer 33 is stacked on the back surface of the insulating film 31. Specifically, the magnetic layer 33 can be formed by attaching a magnetic sheet to the insulating film 31 via the magnetic adhesive layer 34.

The flexible printed wiring boards 30 and 40 manufactured as described above are fixed to the charging device 1 and the wearable device 2 and are connected to the respective control circuits to constitute the contactless charging system.

<How to use>
Next, a method for using the contactless charging system will be described.

In the non-contact charging system, for example, power is transmitted from the power supply module 10 of the charging device 1 to the wearable device 2 provided with the power receiving module 20.

In the power supply by the non-contact charging system, the wearable device 2 is first placed on the upper surface of the pedestal portion 11 so that the through hole 21 of the wearable device 2 fits into the convex portion 12 of the charging device 1. At this time, as shown in FIG. 3, the coil region X of the power supply module 10 and the coil region X of the power reception module 20 face each other.

After the wearable device 2 is mounted, current is supplied to the coiled circuit 32a of the power supply module 10 by the current supply circuit. Thereby, a magnetic flux is generated in the coil-shaped circuit 32a of the power supply module 10, and the magnetic flux penetrates the coil-shaped circuit 32a of the power receiving module 20 facing the magnetic flux. In the coil-like circuit 32a of the power receiving module 20 through which the magnetic flux has passed, a current for generating a magnetic flux that cancels the magnetic flux is generated, and power is supplied to, for example, a rechargeable battery in the wearable device 2 by this current.

<Advantages>
In the non-contact charging system, the power supply module 10 and the power receiving module 20 include flexible printed wiring boards 30 and 40 each having a coil region X. Since the flexible printed wiring boards 30 and 40 can be thinned and miniaturized and can be disposed on a curved surface by bending, the contactless charging system can easily reduce the size of the power supply module 10 and the power reception module 20. . Therefore, the contactless charging system can be easily applied to the wearable device 2. Further, in the non-contact charging system, since the coil region X is annular, the central space becomes a path for the magnetic field, and the inductance is increased with respect to the circuit length and conductor area of the coils of the power supply module 10 and the power reception module 20. it can. Therefore, the contactless charging system including the flexible printed wiring boards 30 and 40 in which the power feeding module 10 and the power receiving module 20 have the coil region X can be easily applied to a wearable device.

[Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the embodiment described above, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

In the above embodiment, the case where the coiled circuit is a spiral conductive pattern has been described, but the conductive pattern of the coiled circuit is not limited to this. For example, for one or both of the coil-like circuits of the power feeding module and the power receiving module, the conductive pattern may be multilayered to constitute a solenoid circuit.

In the above embodiment, the component region is disposed on the protruding portion of the wearable device, but may be disposed on the upper surface or the bottom surface other than the protruding portion of the wearable device.

In the above embodiment, the wearable device has a through-hole in the center, and the case where the through-hole and the convex portion are fitted is described. However, the portion where the convex portion is fitted may not be the through-hole, for example, It may be a recess.

Further, the planar shape of the through hole and the convex portion may not be a circle as long as the charging device and the wearable device can be fitted. For example, the planar shape may be elliptical or polygonal.

In the above embodiment, the case where the planar shape of the pedestal portion of the charging device is a circle has been described. However, the planar shape may be another shape, such as an ellipse or a square shape.

Furthermore, the convex portion of the charging device is not essential, and the shape is not particularly limited as long as the coil area of the flexible printed wiring board of the power supply module and the coil area of the flexible printed wiring board of the power receiving module can face each other during charging. For example, the place where the wearable device should be arranged on a plane may be printed.

In the said embodiment, although the flexible printed wiring board demonstrated the case where the back surface side of an insulating film was equipped with the magnetic body layer containing a ferromagnetic material, the said magnetic body layer is not an essential structural requirement but contains a magnetic body layer. No flexible printed wiring board is contemplated by the present invention.

Although the case where the conductive pattern is provided on one surface of the insulating film of the flexible printed wiring board has been described in the above embodiment, the flexible printed wiring board may include the conductive pattern on both surfaces of the insulating film. That is, as shown in FIG. 6, the coil region of the flexible printed wiring board 50 is laminated on one surface side of the insulating film 31, and the first conductive pattern 51 constituting the first coiled circuit 51 a and the insulating film 31. The second conductive pattern 52 is laminated on the surface opposite to the first conductive pattern 51 to form the second coiled circuit 52a. The first conductive pattern 51 and the second conductive pattern 52 are through holes. 53 may be electrically connected. As described above, the flexible printed wiring board 50 includes the conductive pattern on both surfaces of the insulating film, whereby the inductance can be adjusted while suppressing an increase in the size of the flexible printed wiring board 50. The through hole 53 can be formed by plating the through hole. Alternatively, a conductive paste such as a silver paste or a copper paste may be injected into the through hole and cured by heating.

Furthermore, the flexible printed wiring board further includes two or more conductive patterns having an annular coil region constituting at least a coil-shaped circuit, which is disposed via an insulating film, and the conductive patterns are electrically connected by a through hole. May be connected. That is, in the above embodiment, the case where the conductive pattern is provided on one surface of the insulating film of the flexible printed wiring board has been described. In addition to this conductive pattern, for example, the second conductive pattern is provided on the opposite surface of the insulating film. It is good also as a structure which has a 3rd conductive pattern through the insulating film further on the surface on the opposite side to the said insulating film of the said 2nd conductive pattern. The second conductive pattern and the third conductive pattern have an annular coil region constituting a coiled circuit, and the conductive patterns are electrically connected by through holes. By setting it as such a structure, the said flexible printed wiring board can further increase an inductance, suppressing the increase in a magnitude | size. In addition, although this structure has a total of three conductive patterns, the said flexible printed wiring board can also be set as the structure which has a total of four or more conductive patterns.

In addition, two flexible printed wiring boards having a conductive pattern on one surface of an insulating film are prepared, and the back surfaces thereof are bonded to each other via a magnetic material adhesive layer with a magnetic material layer sandwiched between them. An area may be configured. With such a configuration, it is possible to simultaneously achieve the effect of increasing the inductance due to the magnetic material and the effect of adjusting the inductance while suppressing the increase in size of the power supply module and the power receiving module.

DESCRIPTION OF SYMBOLS 1 Charging device 2 Wearable device 10 Power supply module 11 Base part 12 Convex part 20 Power receiving module 21 Through-hole 30, 40 Flexible printed wiring board 31 Insulating film 32 Conductive pattern 32a Coiled circuit 33 Magnetic body layer 34 Magnetic body adhesive layer 35 Coverlay 35a Cover film 35b Cover film adhesive layer 51 First conductive pattern 52 Second conductive pattern 51a First coiled circuit 52a Second coiled circuit 53 Through hole X Coil region Y Component region Z Connection region

Claims (7)

A flexible printed wiring board having an insulating film and a conductive pattern laminated on at least one surface side of the insulating film,
An annular coil region in which the conductive pattern forms a coiled circuit;
A flexible printed wiring board having an electronic component disposed outside the coil region and having an electronic component electrically connected to the conductive pattern of the coil region. The flexible printed wiring board according to claim 1, wherein the coiled circuit is formed of a spiral conductive pattern. The coil region is laminated on one surface side of the insulating film to form a first coiled circuit, and the second coil shape is laminated on the surface side opposite to the first conductive pattern of the insulating film. The flexible printed wiring board according to claim 1, further comprising a second conductive pattern constituting a circuit, wherein the first conductive pattern and the second conductive pattern are electrically connected through a through hole. . It further includes two or more conductive patterns that are arranged via an insulating film and have at least an annular coil region that constitutes a coiled circuit,
The flexible printed wiring board according to claim 1, wherein the conductive patterns are electrically connected by through holes. The flexible printed wiring board according to claim 1 or 2, further comprising a magnetic layer containing a ferromagnetic material on a surface opposite to the coil region of the insulating film. A power supply module attached to the charging device;
A non-contact charging system comprising a power receiving module attached to an annular wearable device,
Each of the power feeding module and the power receiving module includes the flexible printed wiring board according to claim 1,
A non-contact charging system configured such that a coil region of the flexible printed wiring board of the power supply module and a coil region of the flexible printed wiring board of the power receiving module face each other during charging. The charging device includes: a pedestal portion on which a power supply module is disposed; and a columnar convex portion provided in a state of protruding from an upper surface of the pedestal portion and capable of fitting the wearable device. The contactless charging system described.

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