WO2017057115A1 - Flexible printed circuit board for solenoid coil, solenoid coil, and wearable device - Google Patents

Abstract

A flexible printed circuit board for a solenoid coil, the flexible printed circuit board comprising: an insulating film; a conductive pattern that is laminated on at least one surface side of the insulating film; a coil region; and a connection region. The coil region includes n (n being at least 2) wires that constitute the conductive pattern and that are provided in stripes along the length direction. The connection region extends from the coil region along a first side-edge direction of the coil region from a first side-edge-side end part of a connection-region-extension side edge of the coil region. The connection region has n wires that constitute the conductive pattern and that are continuous from the n wires of the coil region.

Description

Flexible printed wiring board for solenoid coil, solenoid coil and wearable device

The present invention relates to a flexible printed wiring board for a solenoid coil, a solenoid coil, and a wearable device.
This application claims priority based on Japanese Patent Application No. 2015-1910111 filed on Sep. 29, 2015, and incorporates all the description 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 coil (secondary coil) is disposed at a position facing the power feeding coil (primary coil), and a current is generated in the power receiving coil by a magnetic flux generated by passing a current through the power feeding coil. . 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).

JP 2013-169122 A

The solenoid coil flexible printed wiring board according to one aspect of the present invention is a solenoid coil flexible printed wiring board comprising an insulating film and a conductive pattern laminated on at least one surface side of the insulating film, A coil region and a connection region, wherein the coil region is a region having n wirings (n is 2 or more) arranged in a stripe shape along the longitudinal direction as the conductive pattern; Is an area extending from the coil area, extending from the end of the connection area extending side edge of the coil area toward the first side edge of the coil area, As a pattern, an area having n wirings that are continuous from the n wirings in the coil area. At least a portion of the distal end portion of the rear end portion and a plurality of wires of the connection region of the wiring to electrically connect, are formed so as to constitute a solenoid coil.

FIG. 1A is a schematic plan view illustrating a flexible printed wiring board for a solenoid coil according to an aspect of the present invention. FIG. 1B is a schematic cross-sectional view taken along the line ZZ of FIG. 1A. 2A is a schematic side view showing a solenoid coil using the solenoid coil flexible printed wiring board of FIG. 1A. 2B is a schematic plan view showing the solenoid coil of FIG. 2A. FIG. 3 is a schematic plan view showing a flexible printed wiring board for solenoid coil according to an embodiment different from FIG. 1A. FIG. 4 is a schematic side view showing a solenoid coil using the solenoid coil flexible printed wiring board of FIG. FIG. 5 is a schematic partial plan view showing a flexible printed wiring board for a solenoid coil according to an embodiment different from those shown in FIGS. 1A and 3.

[Problems to be solved by the present disclosure]
In recent years, charging systems are becoming widespread as charging devices for portable devices, and in addition to conventional mobile phones, wearable devices such as a wristwatch type and a ring type have been developed as portable devices. Since such wearable devices are small in size, the coils mounted thereon are also required to be downsized.

However, since the conventional planar coil used for the wearable device 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 a 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 wearable device. Moreover, since the conducting wire has a large wire diameter, it is difficult to reduce the size of the planar coil itself. Further, the planar coil cannot efficiently confine the magnetic field in the coil as compared with the solenoid coil, and the charging efficiency is low. For this reason, in order to obtain a constant charge amount, it is necessary to increase the number of turns, and the planar coil is likely to increase in size. Therefore, it is difficult for a conventional charging system using a planar coil to meet the demand for downsizing wearable devices.

Therefore, an object of the present invention is to provide a flexible printed wiring board for a solenoid coil that can be applied to a small wearable device, a solenoid coil, and a wearable device that can be easily miniaturized.

[Effects of the present disclosure]
According to the present disclosure, a solenoid coil that can be applied to a small wearable device can be configured, and the wearable device can be easily downsized.

[Description of Embodiment of the Present Invention]
(1) A flexible printed wiring board for a solenoid coil according to an aspect of the present invention is a flexible printed wiring board for a solenoid coil including an insulating film and a conductive pattern laminated on at least one surface side of the insulating film. A coil region and a connection region, wherein the coil region is a region having n wires (n is 2 or more) arranged in a stripe shape along the longitudinal direction as the conductive pattern, The connection area is an area extending from the coil area, and extends from an end of the connection area extending side edge of the coil area toward the first side edge of the coil area. , A region having n wires continuous from the n wires in the coil region as the conductive pattern, the coil region being spirally wound, and the coil region At least a portion of the distal end portion of the plurality of the plurality of wirings of the rear end portion and the connection region of the wiring to electrically connect, are formed so as to constitute a solenoid coil.

A flexible printed wiring board for a solenoid coil according to an aspect of the present invention is formed by spirally winding a coil region, and electrically connecting at least a part of the front end portions of the plurality of wires in the connection region and the rear end portions of the plurality of wires in the coil region. Thus, a solenoid coil that is remarkably thin and has a small diameter can be configured. Since the flexible printed wiring board for solenoid coil winds the coil region in a spiral shape, the central axis of the solenoid coil can be made longer than the width of the coil region. Therefore, the flexible printed wiring board for the solenoid coil can confine the magnetic field in the coil with high efficiency by the long-axis solenoid coil, and the coil between the power supply coil and the power reception coil when the solenoid coil is used in the charging system. In addition, it is possible to suppress the occurrence of the temperature rise of the surrounding metal due to the leakage magnetic flux. Moreover, the solenoid coil flexible printed wiring board can easily adjust the inductance of the solenoid coil by adjusting the wiring interval, width, thickness, number of wires, the number of turns of the solenoid coil flexible printed wiring board, and the like. Can do.

(2) The connection region includes a crossing region that is continuous from the coil region and the n wirings are arranged in a stripe shape, and a folded connection region that is continuous from the tip of the crossing region, The leading ends of the n wirings in the folded connection region are located at the first side edge or the second side edge of the folded connection region, and the rear end portions of the n wirings in the coil region are the second side of the coil region. It may be located on the side edge. By positioning the front and rear ends of the n wirings as described above, wiring can be easily performed by superimposing the second side edge of the coil region and the first side edge or the second side edge of the folded connection region. The front end portion and the rear end portion can be aligned.

(3) The number of n wires in the coil region is ascending order from the connection region extending side edge, and the number of n wires in the folded connection region is the number of n wires in the coil region to which the wires are connected. When the number is the same as the wiring number, the vertical distance from the front end of the bridge region at the front end position of the kth wiring (k is 1 to n) in the folded connection region is the rear end of the k + 1th wiring in the coil region. It is good to correspond with the perpendicular distance from the said connection area extension side edge of a part position. By matching the vertical distance from the front end of the transfer area of the k-th wiring in the folded connection area with the vertical distance from the connection area extending side edge of the rear end position of the k-th wiring in the coil area, When the second side edge and the first side edge of the folded connection region are overlapped, the positions of the front end portion and the rear end portion of the n wires to be connected coincide with each other. Can be shortened. Therefore, downsizing is further promoted.

(4) The number of n wirings in the coil region is set in ascending order from the connection region extending side edge, and the number of n wirings in the folded connection region is n wirings in the coil region to which these wirings are connected. If the vertical distance from the tip of the bridge region at the tip of the k-th wiring (k is 1 to n−1) in the folded connection region is equal to the number of the k + 1-th wiring in the coil region, It is good to correspond with the perpendicular | vertical distance from the said connection area | region extension side edge of an edge part position. By matching the vertical distance from the front end of the transfer area of the k-th wiring in the folded connection area with the vertical distance from the connection area extending side edge of the rear end position of the (k + 1) -th wiring in the coil area, When the second side edge of the coil region and the first side edge of the folded connection region are overlapped, the positions of the front end portion and the rear end portion of (n−1) wirings to be connected coincide with each other (n -1) The length of the wiring can be shortened. Therefore, downsizing is further promoted.

(5) The n wirings in the folded connection region are connected to the first surface side and the second surface side of the insulating film through the through holes, and the tip ends thereof are located at the first side edge of the folded connection region. It is good to have. By positioning the leading ends of the n wirings in the folded connection region at the first side edge of the folded connection region, the connection can be performed while visually confirming the connection state of the leading and trailing ends of the wiring. Connection of the front end portion and rear end portion of the book wiring can be further facilitated. Furthermore, the length of the connection wiring can be shortened by wiring three-dimensionally through the through hole.

(6) The solenoid coil flexible printed wiring board according to one aspect of the present invention may further include an insulating layer laminated on the outer surface side of the conductive pattern. When the flexible printed wiring board for solenoid coil further includes an insulating layer laminated on the outer surface side of the conductive pattern, when connecting the wiring by folding the folded connection region, other than the leading and trailing ends of the n wirings Therefore, it is possible to easily prevent the wiring from being short-circuited.

(7) A solenoid coil according to one aspect of the present invention uses the flexible printed wiring board for a solenoid coil according to one aspect of the present invention, spirally winds the coil region, and after the plurality of wirings in the coil region It is formed by electrically connecting at least a part of the end portions and the tip portions of the plurality of wirings in the connection region.

Since the solenoid coil according to one aspect of the present invention uses the solenoid coil flexible printed wiring board according to one aspect of the present invention, a solenoid coil that is much thinner and has a small diameter can be configured. Therefore, the solenoid coil can be easily applied to a wearable device.

(8) The solenoid coil according to an aspect of the present invention may further include an annular ferromagnetic material layer superimposed on the inside or outside of the wound flexible printed wiring board for solenoid coil. The solenoid coil further comprises an annular ferromagnetic material layer superimposed on the inside or outside of the wound flexible printed wiring board for the solenoid coil, so that the magnetic material absorbs the magnetic flux and the inductance of the solenoid coil. Can be increased.

(9) A wearable device according to an aspect of the present invention includes a solenoid coil according to an aspect of the present invention. The wearable device may include the solenoid coil as a non-contact power supply coil or a non-contact power reception coil. Since the wearable device includes the solenoid coil, the wearable device can be easily downsized.

It should be noted that “connecting” a set of n wires means that an electrical connection relationship is formed when the solenoid coil is configured.

[Details of the embodiment of the present invention]
Hereinafter, a flexible printed wiring board for a solenoid coil, a solenoid coil, and a wearable device according to an embodiment of the present invention will be described with reference to the drawings as appropriate.

[First embodiment]
<Flexible printed wiring board for solenoid coil>
A solenoid coil flexible printed wiring board 1 shown in FIGS. 1A and 1B includes an insulating film 11 and a conductive pattern 12 laminated on the first surface side of the insulating film 11. The solenoid coil flexible printed wiring board 1 further includes an insulating layer (cover lay 13) laminated on the outer surface side of the conductive pattern 12.

The solenoid coil flexible printed wiring board 1 includes a coil area A and a connection area B. The coil region A has a strip shape, and has five wirings 21 to 25 arranged in a stripe shape along the longitudinal direction as the conductive pattern 12. The connection area B extends from the coil area A. The connection region B is extended from the end of the connection region extending side edge 93 of the coil region A on the first side edge 91 side toward the first side edge 91 of the coil region A, and is formed as a conductive pattern 12 of the coil region A. There are five wirings 31 to 35 continuous from the five wirings 21 to 25. Further, the connection region B is continuous from the coil region A, has a crossover region B1 in which five wires 31 to 35 are arranged in a stripe shape, and a folded connection region B2 continuous from the tip of the crossover region B1. With. The spanning region B1 and the folded connection region B2 can be strip-shaped or rectangular. The longitudinal direction of the coil area A is the direction of the connection area extending side edge 93.

Further, the solenoid coil flexible printed wiring board 1 has a control circuit region C that is disposed outside the coil region A and has an electronic component 14 that is electrically connected to the conductive pattern 12. Furthermore, it has a control wiring region D that connects the coil region A and the control circuit region C.

In the following description, the numbers of the five wires 21 to 25 in the coil region A are set in ascending order from the connection region extending side edge 93, and the numbers of the five wires 31 to 35 in the folded connection region B2 are connected by these wires. The number is the same as that of the five wires in the coil area A.

The order in which the tip positions of the five wires 31 to 35 in the folded connection region B2 are separated from the transfer region tip 94 is the connection region of the five wires 21 to 25 in the coil region A to which these wires are connected. This is the same as the order of separation from the extended side edge 93. The kth wirings 21 to 24 (k = 1 to 4) in the coil region A are continuous with the (k + 1) th wirings 32 to 35 in the connection region B. The fifth wiring 25 in the coil area A is continuous with the first wiring 31 in the connection area B. Further, the wiring 21 is divided for connection of the electronic component 14 in the control circuit region C.

The solenoid coil flexible printed wiring board 1 is formed by spirally winding the coil region A, and at least one of the rear end portions of the plurality of wires 21 to 25 in the coil region A and the front end portions of the plurality of wires 31 to 35 in the connection region B. By electrically connecting the parts, the solenoid coil 100 shown in FIGS. 2A and 2B is formed.

(Insulating film)
The insulating film 11 is a base film (base material) for forming the conductive pattern 12.

The main component of the insulating film 11 is a resin. The resin used for the insulating film 11 is not particularly limited as long as it has insulating properties. As the insulating film 31, a resin film having flexibility and electrical insulation and formed in a sheet shape can be employed. Examples of the material for the resin film include polyimide, polyethylene terephthalate, liquid crystal polymer, and fluororesin.

The lower limit of the average thickness of the insulating film 11 is preferably 5 μm, and more preferably 10 μm. The upper limit of the average thickness of the insulating film 11 is preferably 50 μm, and more preferably 40 μm. When the average thickness of the insulating film 11 is less than the above lower limit, the insulating strength of the insulating film 11 may be insufficient. When the average thickness of the insulating film 11 exceeds the upper limit, the flexible printed wiring board 1 for solenoid coil may be unnecessarily thick.

The lower limit of the average width of the coil region A of the insulating film 11 is preferably 20 mm, and more preferably 30 mm. The upper limit of the average width of the coil region A of the insulating film 11 is preferably 45 mm, and more preferably 40 mm. When the average width of the coil region A of the insulating film 11 is less than the lower limit, the area that can form the solenoid coil 100 is insufficient, and thus a desired inductance may not be obtained. When the average width of the coil area A of the insulating film 11 exceeds the upper limit, the solenoid coil 100 becomes unnecessarily large, which may be contrary to the demand for downsizing the wearable device.

The average length of the coil region A of the insulating film 11 is obtained by multiplying a desired diameter of the solenoid coil 100 formed by winding the solenoid coil flexible printed wiring board 1 by a value obtained by multiplying the circumference ratio π by the solenoid coil flexible length. A value obtained by multiplying the number of turns of the printed wiring board 1 can be obtained.

The size of the folded connection region B2 of the insulating film 11 is not particularly limited. The folded connection region B2 can be formed in a square shape in which the average width of the coil region A of the insulating film 11 is one side length, for example. By setting the folded connection region B2 to have a square shape and having one side having the above length, the five wirings 31 to 35 can be reliably provided in the folded connection region B2. Moreover, when the folded connection region B2 is folded by making the folded connection region B2 into a square shape and having one side thereof having the above length, the first side edge 91 of the coil region A and the first side edge of the folded connection region B2 95 overlaps without excess or deficiency, so that the front end portion and the rear end portion of the five wires can be easily connected while suppressing an increase in the area of the folded connection region B2.

The average length of the spanning region B1 of the insulating film 11 (the average length in the extending direction from the coil region A) is the central axis desired for the solenoid coil 100 formed by winding the flexible printed wiring board 1 for solenoid coil. Determined by the length of Specifically, the average length of the transfer area B1 is determined by a value obtained by subtracting the width of the coil area A from the length of the central axis. Further, the average width of the spanning region B1 (the average length in the direction parallel to the longitudinal direction of the coil region A) is not particularly limited, but may be a length equivalent to the average width of the folded connection region B2. By making the average width of the transfer area B1 equal to the average width of the folded connection area B2, the five wirings 31 to 35 can be reliably provided in the transfer area B1.

(Conductive pattern)
The material of the conductive pattern 12 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 12 can be formed of copper. Further, the surface of the conductive pattern 12 may be plated with gold, silver, tin or the like.

The lower limit of the average thickness of the conductive pattern 12 is preferably 0.1 μm, and more preferably 1 μm. The upper limit of the average thickness of the conductive pattern 12 is preferably 100 μm, and more preferably 80 μm. When the average thickness of the conductive pattern 12 is less than the above lower limit, the internal resistance may increase and the loss may be excessive, and the strength may be insufficient and the solenoid coil 100 may be easily torn. When the average thickness of the conductive pattern 12 exceeds the above upper limit, the solenoid coil flexible printed wiring board 1 may be unnecessarily thick.

The lower limit of the average wiring width in the coil area A and the connection area B is preferably 0.03 mm, and more preferably 0.1 mm. The upper limit of the average wiring width in the coil region A and the connection region B is preferably 1.5 mm, and more preferably 1.25 mm. When the average width of the wiring in the coil area A and the connection area B is less than the lower limit, the mechanical strength of the solenoid coil 100 is insufficient, and there is a possibility of breaking. When the average width of the wiring in the coil area A and the connection area B exceeds the upper limit, a sufficient number of turns cannot be secured and a desired inductance may not be obtained. In addition, the pitch between wirings in the coil area A and the connection area B is not particularly limited, but may be, for example, 0.02 mm to 4.5 mm.

(Coverlay)
The coverlay 13 mainly protects the conductive pattern 12 and prevents the wiring from being short-circuited except at the front end portion and the rear end portion of the five wirings when the folded connection region B2 is folded and the wiring is connected. It is an insulating layer. The coverlay 13 has a cover film 13a and a cover film adhesive layer 13b.

The cover film 13a has flexibility and insulation. Examples of the main component of the cover film 13a include polyimide, epoxy resin, phenol resin, acrylic resin, polyester, thermoplastic polyimide, polyethylene terephthalate, fluororesin, and liquid crystal polymer. In particular, polyimide is preferable from the viewpoint of heat resistance. Further, the cover film 13a may contain a resin other than the main component, a weathering agent, an antistatic agent, and the like.

Although the minimum of the average thickness of the cover film 13a is not specifically limited, 3 micrometers is preferable and 10 micrometers is more preferable. Moreover, although the upper limit of the average thickness of the cover film 13a is not specifically limited, 500 micrometers is preferable and 150 micrometers is more preferable. When the average thickness of the cover film 13a is less than the lower limit, the protection of the conductive pattern 12 may be insufficient, and the insulating property of the cover film 13a may be insufficient. When the average thickness of the cover film 13a exceeds the above upper limit, the protective effect of the conductive pattern 12 may be reduced and the flexibility of the cover film 13a may be insufficient.

The adhesive constituting the cover film adhesive layer 13b is not particularly limited, but is preferably excellent in flexibility and heat resistance. Examples of the adhesive constituting the cover film adhesive layer 13b 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 13b is preferably 5 μm and more preferably 10 μm. Further, the upper limit of the average thickness of the cover film adhesive layer 13b is preferably 50 μm, and more preferably 40 μm. When the average thickness of the cover film adhesive layer 13b is less than the above lower limit, the adhesive strength of the cover lay 13 to the conductive pattern 12 may be insufficient. When the average thickness of the cover film adhesive layer 13b exceeds the upper limit, the solenoid coil flexible printed wiring board 1 may be unnecessarily thick.

(Coil area)
The coil area A has five wirings 21 to 25 arranged in a stripe shape along the longitudinal direction as the conductive pattern 12.

The configuration of the five wirings 21 to 25 arranged in a stripe shape in the coil region A is not particularly limited, but may be a linear configuration, for example, arranged in parallel and at approximately equal intervals. The rear ends of the five wires 21 to 25 in the coil area A are located at the second side edge 92. Here, “substantially parallel” means that the angle formed is within ± 10 °. Further, “substantially equidistant” means that the difference between the average interval and the interval between each wiring is within ± 5% of the average interval.

The front end portions on the first side edge 91 side of the five wires 21 to 25 in the coil area A are continuous with the connecting wires disposed on the second surface side of the insulating film 11 through the through holes 41 to 45. The connection wiring continues to the five wirings 31 to 35 in the connection region B. The through holes 41 to 45 can be formed by forming a through hole in the insulating film 11 and plating the through hole with a metal such as copper. It can also be formed by injecting silver paste, copper paste or the like into the through-holes and curing them by heating. The diameters of the through holes 41 to 45 are appropriately selected in consideration of processability, conduction characteristics, etc., and can be set to 350 μm, for example.

Further, it is preferable that the connection wiring that is continuous with the five wirings 21 to 25 in the coil area A is linear and substantially parallel to the first side edge 91 of the coil area A and at substantially equal intervals. By disposing the connection wirings as described above, the five wirings 21 to 25 in the folded coil region A and the connection region B can be formed with a relatively short wiring distance, so-called Manhattan distance, while suppressing a short circuit between the wirings. Five wires 31 to 35 can be connected.

(Connection area)
The connection region B includes a bridge region B1 and a folded connection region B2, and includes five wirings 31 to 35 continuous as the conductive pattern 12 from the five wirings 21 to 25 in the coil region A. That is, the five wirings 31 to 35 in the connection region B are disposed across the spanning region B1 and the folded connection region B2.

In the transfer area B1, the five wirings 31 to 35 in the connection area B are connected to the connection wiring on the second surface side of the insulating film 11. Further, in the folded connection region B2, the tip portions of the five wires 31 to 35 in the connection region B are located at the first side edge 95 on the first surface side of the insulating film 11. In other words, the five wirings 31 to 35 in the connection region B are continuous to the first surface side of the insulating film 11 through the through holes 51 to 55 in the folded connection region B2, and the leading ends thereof are connected to the first side edge 95. positioned.

The vertical distance from the leading end position 94 of the k-th wirings 31 to 35 (k = 1 to 5) in the folded connection region B2 is the position of the rear end position of the k-th wirings 21 to 25 in the coil region A. This coincides with the vertical distance from the connection region extending side edge 93. With such a configuration, when the second side edge 92 of the coil region A and the first side edge 95 of the folded connection region B2 are overlapped, the positions of the front end portion and the rear end portion of the five wires to be connected are Since they match, the length of the five wires can be shortened. Therefore, downsizing of the solenoid coil 100 is further promoted.

The portions of the five wirings 31 to 35 in the connection region B that are disposed on the first surface side of the insulating film 11 are disposed substantially parallel to the longitudinal side of the coil region A and at substantially equal intervals. Good. Further, the portions of the five wirings 31 to 35 in the connection region B that are disposed on the second surface side of the insulating film 11 are linear and are substantially parallel to the first side edge 91 of the coil region A and at substantially equal intervals. It is good to be arranged in. By disposing the five wirings 31 to 35 in the connection region B as described above, the five wirings 31 in the connection region B can be prevented with a relatively short wiring distance, that is, a so-called Manhattan distance, while suppressing a short circuit between the wirings. ~ 35 can be wired.

The through holes 51 to 55 are positions where the wirings arranged on the first surface side and the wirings arranged on the second surface side of the five wirings 31 to 35 in the connection region B intersect each other. The wiring on the first surface side and the wiring on the second surface side are electrically connected.

(Control circuit area)
In the control circuit region C, an electronic component 14 for controlling power feeding or power reception is mounted, and the electronic component 14 is electrically connected to the solenoid coil 100 in the coil region A by, for example, a conductive pattern 12. Specifically, the electronic component 14 passes through the control wiring region D at a pair of end portions opposed to each other with the divided portion of the first wiring 21 of the coil region A serving as the front end portion and the rear end portion of the solenoid coil 100 interposed therebetween. Are connected through wirings 27 and 28 to be connected.

(Control wiring area)
The control wiring area D is an area that is connected to the coil area A and the control circuit area C and electrically connects the circuits of the coil area A and the control circuit area C by the conductive pattern 12.

The coil area A, the connection area B, the control circuit area C, and the control wiring area D may be provided on a single flexible printed wiring board, or these may be connected using different flexible printed wiring boards. May be. In the case of a single flexible printed wiring board, the coil area A, the connection area B, the control circuit area C, and the control wiring area D can be configured 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. Known methods include, for example, bump connection, firing of metal paste, pressure bonding using an anisotropic conductive film, welding of conductors, and the like.

<Manufacturing method of flexible printed wiring board for solenoid coil>
The solenoid coil flexible printed wiring board 1 can be easily and reliably manufactured by a manufacturing method including a conductive pattern forming process and a coverlay stacking process.

(Conductive pattern formation process)
First, in the conductive pattern forming step, a conductive pattern is formed by laminating a conductive material on the insulating film 11. The planar shape of the wiring of the conductive pattern 12 can be formed by an appropriate method according to the method of laminating the conductive material, for example, by masking and etching the metal film laminated on the insulating film 11. For example, the metal film may be formed by sticking a metal foil or the like to the insulating film 11 with an adhesive or the like, or may be formed by vapor-depositing a metal on the insulating film 11. Moreover, when forming the conductive pattern 12 with a conductive paste, the wiring can be formed by a printing technique.

(Coverlay lamination process)
Next, in the cover lay stacking step, the cover lay 13 is stacked on the surface of the conductive pattern 12. Specifically, the coverlay 13 can be formed by sticking the cover film 13a to the conductive pattern 12 via the cover film adhesive layer 13b.

As described above, the flexible printed wiring board 1 for the solenoid coil is formed.

[Solenoid coil]
The solenoid coil 100 shown in FIGS. 2A and 2B uses the solenoid coil flexible printed wiring board 1 and spirally winds the coil area A, and the rear end of the five wires in the coil area A and the connection area B 5. It is formed by electrically connecting at least a part of the front end portion of the book wiring. The solenoid coil 100 further includes an annular ferromagnetic material layer 101 superimposed on the inner side of the wound solenoid coil flexible printed wiring board 1. 2A and 2B, the same components as those of the solenoid coil flexible printed wiring board 1 are denoted by the same reference numerals, and description thereof is omitted.

<Ferromagnetic material layer>
The ferromagnetic material layer 101 is laminated on the back side of the solenoid coil flexible printed wiring board 1 via a magnetic adhesive layer. The ferromagnetic material layer 101 includes a ferromagnetic material.

The ferromagnetic material layer 101 captures and blocks the magnetic flux formed by the solenoid coil 100. The ferromagnetic material layer 101 only needs to be able to efficiently capture the magnetic flux by including a ferromagnetic material. The ferromagnetic material layer 101 is preferably flexible, and for example, a magnetic sheet having magnetic powder and its binder can be used. As a material of the magnetic powder, known materials can be used as magnetic materials constituting magnetic sheets such as magnetic stainless steel, sendust, permalloy, silicon copper, and ferrite. Among them, sendust and permalloy having high magnetic permeability are preferable.

The lower limit of the relative permeability of the ferromagnetic material layer 101 is preferably 20 and more preferably 30. The upper limit of the relative magnetic permeability of the ferromagnetic material layer 101 is preferably 500, and more preferably 300. When the relative permeability of the ferromagnetic material layer 101 is less than the lower limit, a desired inductance may not be obtained because the magnetic flux captured by the solenoid coil 100 is reduced. When the relative magnetic permeability of the ferromagnetic material layer 101 exceeds the upper limit, the direct current resistance of the solenoid coil 100 is increased, and the current flowing through the solenoid coil 100 may be reduced. In addition, the ferromagnetic material layer 101 becomes overspec, and there is a possibility that the wearable device using the solenoid coil 100 may be expensive.

The lower limit of the average thickness of the ferromagnetic material layer 101 is preferably 10 μm, and more preferably 20 μm. The upper limit of the average thickness of the ferromagnetic material layer 101 is preferably 500 μm, and more preferably 300 μm. If the average thickness of the ferromagnetic material layer 101 is less than the lower limit, the magnetic flux formed by the solenoid coil 100 cannot be sufficiently blocked, and the current of the solenoid coil 100 may be reduced. Moreover, when the average thickness of the ferromagnetic material layer 101 exceeds the said upper limit, there exists a possibility that the flexible printed wiring board 1 for solenoid coils may become thick unnecessarily.

The magnetic adhesive layer adheres the ferromagnetic material layer 101 to the flexible printed wiring board 1 for solenoid coil. The material of the adhesive forming the magnetic adhesive layer is not particularly limited, but is preferably excellent in flexibility and heat resistance. Examples of the adhesive that forms the magnetic adhesive layer include resin 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.

The lower limit of the average thickness of the magnetic adhesive layer is preferably 5 μm and more preferably 10 μm. The upper limit of the average thickness of the magnetic adhesive layer is preferably 50 μm, and more preferably 40 μm. When the average thickness of the magnetic adhesive layer is less than the lower limit, the adhesive strength between the solenoid coil flexible printed wiring board 1 and the ferromagnetic material layer 101 may be insufficient. When the average thickness of the magnetic adhesive layer exceeds the above upper limit, the flexible printed wiring board 1 for solenoid coil may be unnecessarily thick.

The lower limit of the inner diameter (inner diameter) of the solenoid coil 100 in plan view is preferably 25 mm, and more preferably 50 mm. The upper limit of the inner diameter of the solenoid coil 100 is preferably 200 mm, and more preferably 160 mm. When the inner diameter of the solenoid coil 100 is less than the lower limit, the solenoid coil 100 may not be stored in the wearable device, or the curvature may increase and the solenoid coil flexible printed wiring board 1 constituting the solenoid coil 100 may be damaged. is there. Even when the inner diameter of the solenoid coil 100 exceeds the upper limit, the solenoid coil 100 may not be stored inside the wearable device.

The lower limit of the length of the central axis of the solenoid coil 100 is preferably 20 mm, and more preferably 30 mm. The upper limit of the length of the central axis of the solenoid coil 100 is preferably 50 mm, and more preferably 40 mm. When the length of the central axis of the solenoid coil 100 is less than the lower limit, the magnetic field confinement effect in the coil may be insufficient. When the length of the central axis of the solenoid coil 100 exceeds the above upper limit, there is a possibility that it is against the demand for downsizing the wearable device.

The lower limit of the number of turns (the number of spiral turns) of the coil area A is preferably 2, and more preferably 3. When the number of spiral turns is less than the lower limit, the electromotive force induced in the solenoid coil 100 may be insufficient. The upper limit of the number of turns of the flexible printed wiring board 1 for solenoid coil is not particularly limited.

The spiral angle when the coil region A is spirally wound may be less than 90 degrees. The lower limit of the spiral angle is preferably 35 degrees, and more preferably 40 degrees. The upper limit of the spiral angle is preferably 55 degrees, and more preferably 50 degrees. When the spiral angle exceeds the above upper limit, the length of the central axis of the solenoid coil 100 becomes small, so that the magnetic field confinement effect in the coil may be insufficient. When the spiral angle is less than the above lower limit, the area of the portion where the flexible printed wiring board 1 for solenoid coil is overlapped and wound is reduced, so that the strength of the solenoid coil 100 may be insufficient. Here, the “spiral angle” means an angle (acute angle) between the spiral direction and the central axis of the solenoid coil 100.

<Solenoid coil manufacturing method>
The solenoid coil 100 can be easily and reliably manufactured by a manufacturing method including a magnetic material layer lamination step and a winding step.

(Magnetic material layer lamination process)
First, in the magnetic material layer laminating step, the ferromagnetic material layer 101 is laminated on the back surface of the solenoid coil flexible printed wiring board 1. Specifically, the ferromagnetic material layer 101 can be laminated by adhering a magnetic sheet to the insulating film 11 of the solenoid coil flexible printed wiring board 1 via a magnetic adhesive layer.

(Winding process)
Next, in the winding step, the solenoid coil flexible printed wiring board 1 on which the ferromagnetic material layer 101 is laminated is wound to form the solenoid coil 100.

In this step, first, the flexible printed wiring board 1 for the solenoid coil is formed so that, for example, the striped wirings 21 to 25 in the coil area A are on the outer surface side of the solenoid coil 100 with respect to the insulating film 11. Winding is performed a desired number of times so that the second side edge 92 is outside the winding of the flexible printed wiring board 1 for solenoid coil. At this time, the flexible printed wiring board 1 for the solenoid coil is extended from the coil area A of the connection area B so that the second side edge 92 of the coil area A overlaps with the folded connection area B2 when the folded connection area B2 is folded. Wind spirally in the direction. The striped wirings 21 to 25 in the coil area A are on the inner surface side of the solenoid coil 100 with respect to the insulating film 11, and the second side edge 92 is the winding of the solenoid coil flexible printed wiring board 1. The solenoid coil flexible printed wiring board 1 can be wound so as to be inside.

Next, the folded connection region B2 is folded back so that the first surface side of the insulating film 11 of the solenoid coil flexible printed wiring board 1 overlaps the portion forming the outer surface of the solenoid coil 100 of the solenoid coil flexible printed wiring board 1. At this time, the front end portion and the rear end portion of the wiring to be connected so that the rear end portions of the five wirings 21 to 25 in the coil region A overlap with the front end portions of the five wirings 31 to 35 in the folded connection region B2. Match the position of.

Finally, the rear end of the wiring located at the second side edge 92 of the coil area A and the front end of the wiring located at the first side edge 95 of the folded connection area B2 are connected. That is, the kth wirings 31 to 35 (k = 1 to 5) in the folded connection region B2 are electrically connected to the kth wirings 21 to 25 in the coil region A.

As the connection method, a known method can be used. As a well-known method, for example, there is a method in which bumps are arranged and connected to the opening from which the cover lay of the overlapping portion of the leading end portion and the trailing end portion of the wiring is removed. Further, instead of the bump, the connection may be made by baking a metal paste applied to the opening. Furthermore, the method of connecting by the crimping | compression-bonding using an anisotropic electrically conductive film, the method of connecting by welding of a conductor, etc. are mentioned.

As described above, the striped wirings 21 to 25 in the coil region A are connected in series, and the solenoid coil 100 is formed.

[Wearable device]
A wearable device according to an aspect of the present invention includes a solenoid coil 100. The wearable device includes the solenoid coil 100 as a non-contact power supply coil or a non-contact power reception coil.

The wearable device according to one embodiment of the present invention can be, for example, a hollow columnar shape with a part protruding radially outward. The wearable device has a ring shape having a through hole in the center. By making the wearable device into such a shape, for example, the wearable device can be fitted around a finger and carried.

The arrangement method of the solenoid coil 100 in the wearable device is not particularly limited. For example, the wearable device has a hollow structure in which the bottom surface is formed from another plate material, the solenoid coil 100 is disposed on the top surface of the other plate material, and then the plate material is fixed to the wearable device with an adhesive or a screw, A method of embedding the solenoid coil 100 when molding a wearable device can be exemplified.

<Advantages>
The flexible printed wiring board 1 for a solenoid coil has a coil region A spirally wound and electrically connects at least a part of the front end portion and the rear end portion thereof, so that the solenoid coil 100 is extremely thin and has a small diameter. Can be configured. Since the flexible printed wiring board 1 for solenoid coils winds the coil area A in a spiral shape, the central axis of the solenoid coil 100 can be made longer than the width of the coil area A. Accordingly, the flexible printed wiring board 1 for solenoid coil can confine the magnetic field in the coil with high efficiency by the long-axis solenoid coil 100, and between the feeding coil and the receiving coil when the solenoid coil 100 is used in the charging system. In addition to enhancing the coupling of the coils, it is possible to suppress the occurrence of a temperature rise of the surrounding metal due to the leakage magnetic flux. Moreover, the flexible printed wiring board 1 for solenoid coils easily adjusts the inductance of the solenoid coil 100 by adjusting the wiring interval, width, thickness, number of wires, the number of turns of the flexible printed wiring board 1 for solenoid coils, and the like. be able to. Therefore, the wearable device including the solenoid coil 100 using the solenoid coil flexible printed wiring board 1 can be easily downsized.

Further, the flexible printed wiring board 1 for the solenoid coil is arranged such that the wirings 21 to 25 in the coil area A and the wirings 31 to 35 in the folded connection area B2 are arranged in the same order in the order of separation from the transfer area tip 94. Since the number of wirings that need to be bypassed when connecting the part and the rear end part can be reduced, the wiring pattern can be simplified. In addition, since the wirings can be connected with a single flexible printed wiring board for solenoid coil, miniaturization of the solenoid coil 100 is promoted.

Further, the flexible printed wiring board 1 for solenoid coil is arranged such that the tips of the five wirings 31 to 35 in the folded connection region B2 are positioned at the first side edge 95, so that the wirings 31 to 35 in the folded connection region B are visually observed. Since the connection can be performed while confirming the connection state of the front end portion of 35 and the rear end portions of the wirings 21 to 25 in the coil area A, the front end portion and the rear end portion of the five wirings can be more easily connected. Furthermore, the solenoid coil flexible printed wiring board 1 can be three-dimensionally wired through the through holes 51 to 55 to shorten the length of the connection wiring.

[Second Embodiment]
<Flexible printed wiring board for solenoid coil>
The solenoid coil flexible printed wiring board 2 shown in FIG. 3 includes an insulating film 11 and a conductive pattern 12 laminated on the first surface side of the insulating film 11. The solenoid coil flexible printed wiring board 1 further includes an insulating layer (coverlay) laminated on the outer surface side of the conductive pattern 12.

The solenoid coil flexible printed wiring board 2 includes a coil area A and a connection area B. The coil region A has a strip shape, and has five wirings 21 to 25 arranged in a stripe shape along the longitudinal direction as the conductive pattern 12. The connection area B extends from the coil area A. The connection region B is extended from the end of the connection region extending side edge 93 of the coil region A on the first side edge 91 side toward the first side edge 91 of the coil region A, and is formed as a conductive pattern 12 of the coil region A. There are five wirings 31 to 35 continuous from the five wirings 21 to 25. Further, the connection region B is continuous from the coil region A, has a crossover region B1 in which five wires 31 to 35 are arranged in a stripe shape, and a folded connection region B2 continuous from the tip of the crossover region B1. With. The spanning region B1 and the folded connection region B2 can be strip-shaped or rectangular. The longitudinal direction of the coil area A is the direction of the connection area extending side edge 93.

Further, the solenoid coil flexible printed wiring board 2 has a control circuit region C that is disposed outside the coil region A and has an electronic component 14 that is electrically connected to the conductive pattern 12. Furthermore, it has a control wiring region D that connects the coil region A and the control circuit region C.

The order in which the tip positions of the five wires 31 to 35 in the folded connection region B2 are separated from the transfer region tip 94 is the connection region of the five wires 21 to 25 in the coil region A to which these wires are connected. This is the same as the order of separation from the extended side edge 93.

The solenoid coil flexible printed wiring board 2 is formed by spirally winding the coil area A, and at least one of the rear ends of the plurality of wirings 21 to 25 in the coil area A and the front ends of the plurality of wirings 31 to 35 in the connection area B. The solenoid coils 200 shown in FIG. 4 are formed by electrically connecting the parts.

Since the insulating film 11, the conductive pattern 12, and the coverlay are configured in the same manner as in the first embodiment, description thereof is omitted.

(Coil area)
The coil area A has five wirings 21 to 25 arranged in a stripe shape along the longitudinal direction as the conductive pattern 12.

The configuration of the five wirings 21 to 25 arranged in the stripe shape of the coil area A is not particularly limited, but may be a linear configuration, for example, arranged substantially parallel and at substantially equal intervals. The rear ends of the five wires 21 to 25 in the coil area A are located at the second side edge 92.

The five wires 21 to 25 are preferably inclined with respect to the longitudinal direction of the coil region A from the first side edge 91 to the second side edge 92 of the coil region A. The five wires 21 to 25 have a tilt angle θ [°] of the wires 21 to 25 with respect to the longitudinal direction of the coil region A, an average interval W [mm] between the wires 21 to 25, and a flexible print for solenoid coils. When the length of the coil area A of the wiring board 1 is L [mm], the following formula (1) is preferably satisfied.
tan θ = W / L (1)

By configuring the wirings 21 to 25 in the coil area A as described above, when the solenoid coil 100 is configured by winding the solenoid coil flexible printed wiring board 1, the conductor pitch of the solenoid coil becomes equal. For this reason, in the solenoid coil 100, since the windings are uniformly formed in the coil region A, the magnetic field can be confined more efficiently in the coil.

Further, the coil area A has a wiring 26 having a rear end portion on the first surface side of the insulating film 11 at a position separated from the rear end portion of the fifth wiring 25 in the direction opposite to the connection region extending side edge side. The rear end portion of the wiring 26 is connected to the tip end portion of the fifth wiring 35 in the connection region B, and constitutes a current extraction line from the solenoid coil 100. On the other hand, the leading end of the wiring 26 is connected to the electronic component 14 in the control circuit region C via the wiring 28.

(Connection area)
The connection region B includes a bridge region B1 and a folded connection region B2, and includes five wirings 31 to 35 continuous as the conductive pattern 12 from the five wirings 21 to 25 in the coil region A. That is, the five wirings 31 to 35 in the connection region B are disposed across the spanning region B1 and the folded connection region B2.

In the transfer area B1, the five wires 31 to 35 in the connection area B are arranged on the first surface side of the insulating film 11. Further, in the folded connection region B2, the tips of the five wirings 31 to 35 in the connection region B are located on the first side edge 95 on the second surface side of the insulating film 11. That is, the five wirings 31 to 35 in the connection region B are continuous to the second surface side of the insulating film 11 through the through holes 41 to 45 in the folded connection region B2, and the tip ends thereof are connected to the first side edge 95. positioned.

The vertical distance from the transfer region tip 94 of the position of the tip of the kth wires 31 to 34 (k = 1 to 4) in the folded connection region B2 is the rear end of the (k + 1) th wires 22 to 25 in the coil region A. The position coincides with the vertical distance from the connecting region extending side edge 93. With such a configuration, when the second side edge 92 of the coil region A and the first side edge 95 of the folded connection region B2 are abutted, the positions of the front end portion and the rear end portion of the four wires to be connected coincide with each other. Therefore, the length of the four wires can be shortened. Therefore, downsizing of the solenoid coil 200 is further promoted.

Further, the vertical distance from the connection region extending side edge 93 at the tip end position of the fifth wiring 35 in the connection region B is from the connection region extending side edge 93 at the rear end portion position of the wiring 26 constituting the current extraction line. Matches the vertical distance of.

The portions of the five wirings 31 to 35 in the connection region B that are disposed on the first surface side of the insulating film 11 are disposed substantially parallel to the first side edge 91 of the coil region A and at substantially equal intervals. It is good to be. Further, the portions of the five wirings 31 to 35 in the connection region B that are disposed on the second surface side of the insulating film 11 are straight and are substantially parallel to the longitudinal side of the coil region A and at substantially equal intervals. It is good to be arranged. By disposing the five wirings 31 to 35 in the connection region B as described above, the five wirings 31 in the connection region B can be prevented with a relatively short wiring distance, that is, a so-called Manhattan distance, while suppressing a short circuit between the wirings. ~ 35 can be wired.

The through holes 51 to 55 are positions where the wirings arranged on the first surface side and the wirings arranged on the second surface side of the five wirings 31 to 35 in the connection region B intersect each other. The wiring on the first surface side and the wiring on the second surface side are electrically connected. Such through holes 51 to 55 can be formed by forming a through hole in the insulating film 11 and plating the through hole with a metal such as copper. It can also be formed by injecting silver paste, copper paste or the like into the through-holes and curing them by heating. The diameters of the through holes 51 to 55 are appropriately selected in consideration of processability, conduction characteristics, etc., and can be set to 350 μm, for example.

(Control circuit area)
In the control circuit region C, an electronic component 14 for controlling power feeding or power reception is mounted, and the electronic component 14 is electrically connected to the solenoid coil 100 in the coil region A by, for example, a conductive pattern 12. Specifically, the electronic component 14 includes the two wires 27 and 28, the second side edge 92 side of the first wire 21 in the coil region A serving as the front end portion and the rear end portion of the solenoid coil 100, and the above-described current extraction. It is connected to the first side edge 91 side of the wiring 26 to be a line. Note that the wiring 28 that connects the electronic component 14 and the wiring 26 serving as the current extraction line may be short-circuited with the striped wirings 22 to 25 in the coil region A when disposed on the first surface side of the insulating film 11. Therefore, they are connected on the second surface side of the insulating film 11 through the through holes 46 and 47.

(Control wiring area)
Since the control wiring region D is configured in the same manner as in the first embodiment, description thereof is omitted.

[Solenoid coil]
The solenoid coil 200 shown in FIG. 4 uses the solenoid coil flexible printed wiring board 2 and spirally winds the coil area A. The rear ends of the five wires 21 to 25 in the coil area A and the connection area B 5 It is formed by electrically connecting at least a part of the tips of the wirings 31 to 25 of the book. The solenoid coil 200 further includes an annular ferromagnetic material layer 101 superimposed on the inner side of the wound solenoid coil flexible printed wiring board 2.

The solenoid coil 200 is the same as that of the first embodiment except for the manufacturing method of the solenoid coil, and thus the description other than the manufacturing method of the solenoid coil is omitted.

<Solenoid coil manufacturing method>
The solenoid coil 200 can be easily and reliably manufactured by a manufacturing method including a magnetic material layer lamination step and a winding step.

(Magnetic material layer lamination process)
Since the magnetic material layer lamination step is the same as the magnetic material layer lamination step of the first embodiment, description thereof is omitted.

(Winding process)
Next, in the winding step, the solenoid coil flexible printed wiring board 2 on which the ferromagnetic material layer 101 is laminated is wound to form the solenoid coil 200.

In this step, first, the solenoid coil flexible printed wiring board 2 is arranged such that, for example, the striped wirings 21 to 25 in the coil region A are on the outer surface side of the solenoid coil 200 with respect to the insulating film 11 and the second side edge 92. Is wound a desired number of times so as to be outside the winding of the flexible printed wiring board 2 for solenoid coil. At this time, when the second side edge 92 of the coil area A turns back the folded connection area B2, the flexible printed wiring board 2 for solenoid coil is adjacent to the first side edge 95 of the folded connection area B2. The coil is wound in a spiral shape extending in the extending direction from the coil region A. The striped wirings 21 to 25 in the coil area A are on the inner surface side of the solenoid coil 200 with respect to the insulating film 11, and the second side edge 92 is the winding of the solenoid coil flexible printed wiring board 2. The solenoid coil flexible printed wiring board 2 can be wound so as to be inside.

Next, the folded connection region B2 is folded back so that the first surface side of the insulating film 11 of the solenoid coil flexible printed wiring board 2 overlaps the portion of the solenoid coil flexible printed wiring board 2 that forms the outer surface of the solenoid coil 200. The area B2 is folded back. At this time, the second side edge 92 of the coil region A is adjacent to the first side edge 95 of the folded connection region B2, and the positions of the front end portion and the rear end portion of the wiring to be connected are matched.

Finally, the rear end of the wiring located at the second side edge 92 of the coil area A and the front end of the wiring located at the first side edge 95 of the folded connection area B2 are connected. That is, the kth wiring in the folded connection region B2 and the (k + 1) th wiring in the coil region A are electrically connected.

As the connection method, a known method can be used. As a known method, for example, a method of connecting by bump connection or baking of a metal paste using a small printed wiring board having a plurality of wirings to which the leading end and the trailing end of the wiring can be connected, an anisotropic conductive film is used. The method of connecting by the used crimping, the method of connecting by welding of conductors, etc. are mentioned.

As described above, the striped wirings 21 to 25 in the coil region A are connected in series, and the solenoid coil 200 is formed.

<Advantages>
The flexible printed wiring board 2 for solenoid coil is folded when the folded connection area B2 is folded by positioning the tip ends of the five wires 31 to 35 of the folded connection area B2 on the second surface side of the insulating film 11. The front ends of the five wires 31 to 35 in the connection region B2 are located on the same surface side as the coil region A with respect to the insulating film 11. For this reason, the flexible printed wiring board 2 for solenoid coil visually confirms the connection state of the front ends of the five wires 31 to 35 in the folded connection region B2 and the rear ends of the wires 21 to 25 in the coil region A. Therefore, the connection between the front ends of the five wires 31 to 35 in the folded connection region B2 and the rear ends of the wires 21 to 25 in the coil region A can be further facilitated. Furthermore, the solenoid coil flexible printed wiring board 2 can be three-dimensionally wired through the through holes 51 to 55, thereby shortening the length of the connection wiring.

[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 first embodiment and the second embodiment, the case where the number of wires in the coil region is five has been described, but the number of wires in the coil region is not limited to five. The lower limit of the number of wires in the coil region is preferably 2, and more preferably 3. When the number of wires in the coil region is less than the lower limit, there is a possibility that the electromotive force induced in the solenoid coil is insufficient. The upper limit of the number of wires in the coil area is not particularly limited.

In 1st embodiment and 2nd embodiment, the separation order from the 1st side edge of the front-end | tip part position of several wiring of a return | turnback connection area | region is the 1st side of several wiring position of the coil area | region which those wiring connects. Although the case where it becomes the same as the order of separation from the edge has been described, this is not an essential component, and the order of separation of the two may be different. Even when the separation order is different, the solenoid coil is formed by connecting the leading end portion and the trailing end portion of the wiring by continuously wiring, for example, through the through hole to the opposite surface of the insulating film. Can be configured.

In the first embodiment, the case where the front end located at the first side edge of the wiring in the folded connection region is connected to the rear end of the wiring in the coil region has been described. You may connect by connection wiring. For example, the connection wiring can be configured as follows. First, the surface of the wiring in the folded connection region on the first surface of the insulating film is covered with an insulating coating such as a coverlay or a solder resist. Next, a part of the insulating coating is opened to connect with the wiring in the folded connection region, and the conductive pattern connected to the wiring in the folded connection region is printed on the surface of the insulating coating with a conductive ink or the like. Wiring can be configured. Also when comprised in this way, the front-end | tip part of the wiring of a return | turnback connection area | region and the rear-end part of the wiring of a coil area | region can be connected like 1st embodiment. Further, in the second embodiment, for example, a through hole is provided at the leading end of the wiring in the folded connection region as a connection between the leading end of the wiring in the folded connection region and the rear end of the wiring in the coil region. It may be configured to connect directly to the rear end of the wiring in the region.

In the first embodiment and the second embodiment, the front end portion of the wiring in the folded connection region is located at the first side edge of the folded connection region, and the rear end portion of the wiring in the coil region is the second side of the folded connection region. Although the case where it is located at the edge has been described, the position of the front end of the wiring in the folded connection region and the position of the rear end of the wiring in the coil region are not limited to this. For example, the tip of the wiring in the folded connection region may be located at the second side edge of the folded connection region. In this case, the solenoid coil is wound by winding the flexible printed wiring board for the solenoid coil so that the second side edge of the coil region overlaps the second side edge of the folded connection region when the second side edge of the coil region is folded back in the solenoid coil forming step. Can be configured. In such a configuration, by winding the folded connection region after winding the solenoid coil flexible printed wiring board, the rear end portion of the coil region wiring can be positioned immediately below the leading end portion of the wiring in the folded connection region. . For this reason, it is possible to electrically connect the front-end | tip part of the wiring of a folding | turning connection area | region, and the rear-end part of the wiring of a coil area | region, for example through a through hole. As long as the solenoid coil can be formed by winding the flexible printed wiring board for solenoid coil and folding the folded connection region in this way, the position of the leading end of the wiring in the folded connection region and the position of the rear end of the wiring in the coil region are not limited.

In the first embodiment, the vertical distance from the tip of the transfer region at the tip end position of the kth wiring (k = 1 to 5) in the folded connection region is the extension of the connection region at the rear end portion position of the kth wiring in the coil region. The case where it coincides with the vertical distance from the exit edge has been described. In the second embodiment, the vertical distance from the leading end position of the k-th wiring (k = 1 to 4) in the folded connection area from the front end of the transfer area is the connection at the rear end position of the (k + 1) -th wiring in the coil area. The case where it coincides with the vertical distance from the region extending side edge has been described. These are not essential components, and the vertical distance between them may be different. In this case, for example, the front end of the k-th wiring (k = 1 to 5) in the folded connection region and the rear end of the k-th wiring in the coil region of another printed circuit board provided on the flexible printed wiring board for solenoid coils. They can be connected using wiring or the like.

Moreover, in 1st embodiment and 2nd embodiment, the wiring of the folding | turning connection area | region continues to the 2nd surface side of an insulating film via a through hole, and the front-end | tip part is located in the 1st side edge of a folding | turning connection area | region. However, this is not an essential configuration requirement. For example, a configuration in which the front end portion of the wiring in the folded connection region is located at the second side edge of the folded connection region, or a configuration in which the wiring is connected only by the wiring on the first surface without using the through hole may be employed. As such a configuration, for example, as shown in FIG. 5, the five wirings 31 to 35 in the connection region B are formed in a U shape extending in the order of the X direction, the Y direction, and the X direction. The order of separation of the wirings 31 to 35 from the connection region extending side edge 93 is the same as the order of separation from the connection region extending side edge 93 of the five wirings 21 to 25 in the coil region A to which these wirings are connected. The structure which positions a front-end | tip part in the 2nd side edge 96 of folding | turning connection area | region B2 so that it may become can be mentioned. In this case, the extending portion in the Y direction of the (k + 1) -th wiring is formed in a U shape longer than the extending portion in the Y direction of the k-th wiring, so that the first film of the insulating film 11 is not short-circuited. It can be arranged on only one surface. Note that, when the folded connection region B is folded, for example, the five wires 31 to 35 in the folded connection region B are not short-circuited with the wires 21 to 25 in the coil region A that are not connected, for example, It is necessary that the surface of the extending portion in the Y direction of the wirings 31 to 35 is covered with an insulating coating such as a coverlay or a solder resist.

In the first embodiment and the second embodiment, the case where the coverlay is provided as the insulating layer laminated on the outer surface side of the conductive pattern has been described. However, the insulating layer is not limited to the coverlay, for example, glass coating or the like. May be. Further, the insulating layer is not an essential component, and the insulating layer may be omitted as long as a short circuit between the wirings does not occur.

In the first embodiment and the second embodiment, the case where the solenoid coil includes the ferromagnetic material layer inside the flexible printed wiring board for solenoid coil has been described. However, the ferromagnetic material layer is a flexible printed wiring board for the solenoid coil. May be on the outside. Further, the ferromagnetic material layer is not an essential constituent element, and the solenoid coil may not include the ferromagnetic material layer.

1, 2, 3 Solenoid coil flexible printed wiring board 11 Insulating film 12 Conductive pattern 13 Cover lay 13a Cover film 13b Cover film adhesive layer 14 Electronic components 21, 22, 23, 24, 25, 26, 27, 28 Wiring 31, 32, 33, 34, 35 Wiring 41, 42, 43, 44, 45, 46, 47 Through hole 51, 52, 53, 54, 55 Through hole 91 First side edge 92 of coil area Second side edge of coil area 93 Connection region extending side edge 94 Crossing region front end 95 Folding connection region first side edge 96 Folding connection region second side edge 100, 200 Solenoid coil 101 Ferromagnetic material layer A Coil region B Connection region B1 Crossing region B2 Folded connection area C Control circuit area D Control wiring area

Claims (9)

1. A flexible printed wiring board for a solenoid coil comprising an insulating film and a conductive pattern laminated on at least one surface side of the insulating film,
   A coil area and a connection area;
   The coil region is a region having n wires (n is 2 or more) arranged in a stripe shape along the longitudinal direction as the conductive pattern,
   The connection area is an area extending from the coil area, and extends from an end of the connection area extending side edge of the coil area toward the first side edge of the coil area. , A region having n wires continuous from the n wires in the coil region as the conductive pattern,
   The coil area is spirally wound, and a solenoid coil is configured by electrically connecting at least a part of the rear end portions of the plurality of wires in the coil region and the front end portions of the plurality of wires in the connection region. The flexible printed wiring board for solenoid coils formed.
2. The connection area is
   A spanning area that is continuous from the coil area and in which the n wirings are arranged in a stripe;
   A folded connection area continuous from the end of the transfer area, and
   The tips of the n wirings in the folded connection region are located at the first side edge or the second side edge of the folded connection region,
   The flexible printed wiring board for solenoid coils according to claim 1, wherein a rear end portion of the n wirings in the coil region is located at a second side edge of the coil region.
3. The number of n wirings in the coil area is ascending from the connection area extending side edge, and the number of n wirings in the folded connection area is the number of n wirings in the coil area to which the wirings are connected. Is the same as
   The vertical distance of the position of the tip of the kth wiring (k is 1 to n) in the folded connection region from the tip of the transfer region is the connection region extending side of the position of the rear end of the kth wiring in the coil region The flexible printed wiring board for a solenoid coil according to claim 2, which coincides with a vertical distance from the edge.
4. The number of n wirings in the coil area is ascending from the connection area extending side edge, and the number of n wirings in the folded connection area is the number of n wirings in the coil area to which the wirings are connected. Is the same as
   The vertical distance from the front end position of the k-th wiring (k is 1 to n-1) in the folded connection area from the front end of the transfer area is the connection position of the rear end position of the (k + 1) -th wiring in the coil area. The flexible printed wiring board for solenoid coils according to claim 2, which coincides with a vertical distance from a region extending side edge.
5. The n wirings in the folded connection region continue to the first surface side and the second surface side of the insulating film through the through holes, and the tip ends thereof are located at the first side edge of the folded connection region. The flexible printed wiring board for solenoid coils according to claim 3 or 4.
6. The flexible printed wiring board for solenoid coils according to any one of claims 1 to 5, further comprising an insulating layer laminated on an outer surface side of the conductive pattern.
7. The flexible printed wiring board for solenoid coils according to any one of claims 1 to 6, wherein the coil area is spirally wound, and a plurality of wiring rear end portions of the coil area and the connection area are A solenoid coil formed by electrically connecting at least a part of tip portions of a plurality of wires.
8. The solenoid coil according to claim 7, further comprising an annular ferromagnetic material layer superimposed on an inner side or an outer side of the wound flexible printed wiring board for the solenoid coil.
9. A wearable device comprising the solenoid coil according to claim 7 or 8.

Images