JP2013201297A - Magnetic sheet, transmission coil component, and non-contact charging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sheet capable of contributing to miniaturization/simplification and improvement in characteristics, such as efficiency, of a non-contact charging device and a transmission coil component or the like used therefor, and to achieve miniaturization or the like of a transmission coil component and a non-contact charging device by using the magnetic sheet.SOLUTION: The magnetic sheet for a non-contact charging device has, on the side of one main surface thereof, a first recess which is substantially annular when viewed from a normal direction of the main surface. A distance between the bottom surface of the first recess and the other main surface is smaller than the depth of the first recess.

Description

  The present invention relates to a magnetic sheet that functions as a magnetic shield, a magnetic yoke, or the like. Furthermore, it is related with the transmission coil components and non-contact charging device using the same.

  In recent years, high-performance and high-performance small information communication devices and electronic devices have been promoted. In particular, mobile phones, web terminals, music players, etc. can be used continuously for a long time for convenience as portable devices. It is required to be possible. In these small portable devices, a secondary battery such as a lithium ion battery is used as a power source. This secondary battery charging method uses a contact charging method in which charging is performed by directly contacting the electrode on the power receiving side and the electrode on the power feeding side, and transmission coils are provided on both the power feeding side and the power receiving side, and electromagnetic induction is used. There is a non-contact charging method in which charging is performed by power transmission. Since the contactless charging method does not require an electrode for directly contacting the power feeding device and the power receiving device, it is possible to charge different power receiving devices using the same power feeding device.

  In the non-contact charging method, the magnetic flux generated in the primary transmission coil is fed by generating an electromotive force in the secondary transmission coil through the housing of the power feeding device and the power receiving device. Therefore, in order to obtain high power transmission efficiency in the non-contact charging method, it is necessary to match the central axes of the primary coil and the secondary coil.

  On the other hand, in order to obtain high power transmission efficiency, a magnetic sheet is installed as a coil yoke on the opposite side of the transmission coil from the contact surface of the power feeding device and the power receiving device. Such a magnetic sheet has the following role. The first role is a role as a magnetic shield material. When leakage magnetic flux generated during the charging operation of the non-contact charging device flows to other components such as a metal member constituting the secondary battery, these components generate heat due to eddy current. The magnetic sheet can suppress this heat generation as a magnetic shield material. The second role of the magnetic sheet is to act as a yoke member that recirculates the magnetic flux generated in the coil during charging.

  For the purpose of providing a non-contact charging device with a simple structure while suppressing a decrease in power transmission efficiency, a configuration in which the magnetic attraction means is arranged inside the transmission coil and the central axes of the primary coil and the secondary coil coincide with each other. It is disclosed in Patent Document 1.

WO2011 / 096569

  Since the non-contact charging device is mainly used for charging a power source of a small information communication device, it is necessary to have a small size and a low profile. On the other hand, although the contactless charging device can be reduced in size by the configuration described in Patent Document 1, in order to meet the demands for reducing the size and height of information communication devices and reducing the cost, There was a need for further miniaturization and simplification. Further, when a permanent magnet is used as the positioning / fixing means, the magnetic flux generated from the transmission coil and the magnetic flux generated from the permanent magnet flow through the magnetic sheet as the coil yoke, so that the coil yoke is likely to be partially magnetically saturated. . This tendency becomes prominent when the permanent magnet is simply brought close to the magnetic sheet for miniaturization. If the magnetic sheet in the portion adjacent to the transmission coil is magnetically saturated, the magnetic saturation portion is reduced in permeability, so that the function as a coil yoke cannot be obtained sufficiently, and the power transmission efficiency of the charging device is reduced. . Therefore, when miniaturizing the non-contact charging device, it is necessary to consider the problem of magnetic saturation of the coil yoke.

  In view of these points, an object of the present invention is to provide a magnetic sheet that can contribute to improvement in characteristics such as miniaturization, simplification, and efficiency of a non-contact charging device and a transmission coil component used therein. It is another object of the present invention to reduce the size of transmission coil components and non-contact charging devices using such a magnetic sheet.

  The magnetic sheet of the present invention is a magnetic sheet for a non-contact charging device, and includes a first annular concave portion when viewed from the normal direction of the main surface on one main surface side of the magnetic sheet, The distance between the bottom surface of the first recess and the other main surface is smaller than the depth of the first recess. Here, the term “substantially annular” only needs to be recognized as an annular shape as a whole, and includes not only a complete annular shape but also an elliptical or polygonal annular shape, a configuration in which a part of the ring is cut, and a shape with irregularities on the inside and outside of the ring. It is. According to such a configuration, for example, in a non-contact charging device or a transmission coil component used therefor, a portion surrounded by the substantially annular first recess can be used as a magnetic attracting member disposed to face the permanent magnet. In this case, since the magnetic gap is formed by the first recess, magnetic saturation of the magnetic sheet portion outside the first recess is suppressed. In addition, since the magnetic attracting member disposed to face the permanent magnet can be constituted by a part of the magnetic sheet, it is possible to reduce the size and simplification of the non-contact charging device and the transmission coil component used therefor. Furthermore, the characteristics can be improved by forming the recess so that the distance between the bottom surface of the first recess and the other main surface is smaller than the depth of the recess.

  In the magnetic sheet, the first recess is opposed to the first magnetic layer having a substantially annular opening and the first magnetic layer, and there is no opening at a position corresponding to the opening. The second magnetic layer is preferably used. According to this configuration, the first recess can be formed by a simple method, which contributes to simplification of the process and cost reduction.

  Further, in the magnetic sheet, the first magnetic layer and the second magnetic layer are configured by using a soft magnetic alloy ribbon, and the first magnetic layer is formed by superposing a plurality of the soft magnetic alloy ribbons. It is preferable that the second magnetic layer is formed by using only one layer of the soft magnetic alloy ribbon. Such a configuration contributes to further improvement in efficiency of the transmission coil component.

  Furthermore, in the magnetic sheet, it is preferable that the first recess is C-shaped when viewed from the normal direction of the main surface. According to such a configuration, since the portion surrounded by the first recess and the portion outside the first recess are integrated, the manufacturing process of the magnetic sheet is simplified.

  Further, the magnetic sheet preferably has a second recess having the same depth as the first recess and communicating the first recess with the outer edge side of the magnetic sheet. According to such a configuration, when the substantially annular first concave portion is formed, the portion corresponding to the first concave portion and the portion outside the first concave portion can be integrally removed, so that the first concave portion is formed. There is an advantage that the process can be simplified.

  Furthermore, in the magnetic sheet, it is preferable that the outer edge of the second magnetic layer is inside the outer edge of the first magnetic layer when viewed from the normal direction of the main surface. According to such a configuration, it is possible to reduce the amount of magnetic sheet used, prevent the thin portion of the magnetic sheet from protruding, and prevent damage such as peeling at the outer edge.

  A transmission coil component for a non-contact charging device according to the present invention includes a planar coil and any one of the magnetic sheets, and a portion surrounded by the first recess is a winding axis of the planar coil. The magnetic sheet and the planar coil are arranged to face each other so as to be positioned above. According to such a configuration, the portion surrounded by the first recess that can be used as a part of the magnetic attracting member and the outer portion of the first recess that functions as a coil yoke or the like are integrally configured. The transmission coil component can be reduced in size and simplified.

  The non-contact charging device of the present invention is a non-contact charging device that transmits power between the transmission coil components with two transmission coil components facing each other, and one of the transmission coil components is the coil component, The other of the transmission coil components has a planar coil and a magnetic adsorption member disposed inside the planar coil, and the magnetic adsorption member and a portion surrounded by the first recess are opposed to each other. It is characterized by being arranged. According to such a configuration, the portion surrounded by the first recess, which is a part of the magnetic sheet, functions as a magnetic adsorption member, so the configuration relating to the magnetic adsorption member is simplified and the entire contactless charging device is downsized. Is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the magnetic sheet which can contribute to size reduction, simplification, and the improvement of a characteristic of a non-contact charging device and the transmission coil component used for it can be provided.

It is a figure which shows the electric power feeder and power receiving apparatus which comprise a non-contact charging device. It is a figure which shows embodiment of the magnetic sheet which concerns on this invention. It is a figure which shows other embodiment of the magnetic sheet which concerns on this invention. It is a figure which shows other embodiment of the magnetic sheet which concerns on this invention. It is a figure which shows other embodiment of the magnetic sheet which concerns on this invention. It is a figure which shows other embodiment of the magnetic sheet which concerns on this invention.

  Hereinafter, embodiments of a magnetic sheet, a transmission coil component, and a non-contact charging device according to the present invention will be specifically described with reference to the drawings. However, the present invention is not limited thereto. Moreover, the structure demonstrated in each embodiment is applicable also in other embodiment, unless the meaning of other embodiment is impaired, In that case, the overlapping description is abbreviate | omitted suitably.

  FIG. 1 is a cross-sectional view showing a non-contact charging apparatus that performs power transmission between two transmission coil parts with two transmission coil parts facing each other. One of the transmission coil components is a power receiving device, and the other is a power feeding device. A specific example of the non-contact charging device is, for example, a mobile communication terminal and its charger. The transmission coil component according to the present invention is applied to a power feeding device and / or a power receiving device. The power receiving device includes a battery unit alone in addition to an electronic device main body having a power receiving function such as a portable terminal.

  The power feeding device 14 connected to the AC power supply 12 has a circuit unit 13. The circuit unit 13 includes a rectifier circuit that rectifies an alternating current and a switching circuit that converts the rectified direct current into a high-frequency current having a predetermined frequency. The power feeding device 14 includes a planar coil 9 and a magnetic attracting member 10 disposed inside the planar coil 9. The high-frequency current output from the circuit unit 13 flows through the planar coil 9 that is a primary transmission coil. The planar coil 9 is connected to a resonance capacitor (not shown) and resonates at the same frequency as the predetermined frequency converted by the switching circuit. The power feeding device 14 may be provided with a control circuit for controlling the operation of the switching circuit.

  The power receiving device 7 includes a planar coil 4 that is a secondary transmission coil, and a magnetic sheet 1 as a coil yoke disposed on the rear surface side of the planar coil 4. The magnetic sheet 1 is provided with a substantially annular first concave portion 2 on one main surface side (the planar coil 4 side in FIG. 1) when viewed from the normal direction of the main surface. The side facing the primary transmission coil is referred to as the front side, and the opposite side is referred to as the rear side. A resonance circuit can be configured by arranging a resonance capacitor in addition to the planar coil 4 as a secondary transmission coil. A secondary battery 6 is connected to the planar coil 4 via a rectifier circuit (not shown), and the induced current induced in the planar coil 4 by electromagnetic induction is rectified by the rectifier circuit, and the secondary battery. 6 is charged.

  The power feeding device 14 and the power receiving device 7 are accommodated in a nonmagnetic housing such as resin. Each of the casings has a flat surface, and charging is performed with the flat surfaces facing each other. The power feeding device and the power receiving device are positioned and fixed to each other using the magnetic adsorption member 10 described above. For example, the magnetic attracting member 10 is a magnet or a magnetic yoke that induces a magnetic flux from the magnet. In the configuration shown in FIG. 1, a magnet is disposed as a magnetic attracting member on the power feeding device 14 side, and the magnetic sheet 1 has a function as a magnetic attracting member on the power receiving device side. The magnetic sheet 1 and the planar coil 4 are arranged to face each other so that the portion 3 surrounded by the first recess 2 is located on the winding axis of the planar coil 4. Furthermore, the magnetic attracting member 10 on the power feeding device side and the portion 3 surrounded by the first concave portion are arranged to face each other, and the power feeding device 14 and the power receiving device 7 are caused by the magnetic attracting force between them. Positioned and fixed. The configuration related to the first recess 2 and the portion 3 surrounded by the first recess 2 will be described later.

  The planar coils 4 and 9 are arranged inside the casing so that the winding axis thereof is perpendicular to the flat surface (the surface of the planar coil is parallel to the flat surface). On the opposite side (rear side) of the flat coils 4 and 9, the magnetic sheets 1 and 8 are respectively arranged adjacent to the flat surface. For example, substrates 5 and 11 such as a resin substrate are disposed inside the housing. Note that the configurations of the magnetic sheet and the magnetic adsorption member can be interchanged between the power receiving device and the power feeding device. However, since there is a strong demand for miniaturization of the power receiving device, the configuration of the magnetic sheet according to the present invention is preferably used at least on the power receiving device side. The magnetic sheet 8 on the power feeding device side may be made of the same material as that of the magnetic sheet 1 on the power receiving side, but may be made of a different material. Further, the power receiving substrate 5 may be omitted and the magnetic sheet 1 may be directly attached to the secondary battery 6. The magnetic sheets 1 and 8 are disposed so that the main surfaces thereof overlap or cover the planar coils 4 and 9 between the substrates 5 and 11 on which the secondary battery 6 and the like are installed and the planar coils 4 and 9. Be placed. Therefore, the magnetic flux generated by the planar coils 4 and 9 wound spirally converges on the magnetic sheets 1 and 8, and the magnetic sheet functions as a magnetic yoke or a magnetic shield. The portions of the magnetic sheets 1 and 8 that are opposed to each other in the winding axis direction of the planar coils 4 and 9 will be specifically described below.

(First embodiment of magnetic sheet)
FIG. 2 shows a magnetic sheet used for the power receiving device 7 of the above-described contactless charging apparatus as an example of the magnetic sheet according to the present invention. (A) is the top view which looked at the planar magnetic sheet from the normal line direction of the main surface, (b) is sectional drawing at the time of cut | disconnecting the center of this magnetic sheet in the said normal line direction. The magnetic sheet shown in FIG. 2 has a rectangular outer shape, and has a substantially annular first recess 2 at the center of one flat main surface. The configuration of the magnetic sheet is not limited to such a configuration. For example, the outer shape of the magnetic sheet can take various configurations such as a polygon, a circle, an ellipse, an irregular shape, and a shape with irregularities formed on them. When the magnetic sheet is arranged on the rear surface side of the planar coil to constitute a transmission coil component such as a power receiving device for a non-contact charging device, the function as a coil yoke or a magnetic shield is mainly the portion outside the first recess. Demonstrate. Therefore, when configuring a non-contact charging device, such a shape that the portion covers the planar coil on the power feeding side, that is, the outer edge of the magnetic sheet 1 is outside the outer edge of the planar coil on the power feeding side. -It is preferable to arrange. Further, the substantially annular first recess 2 may be a perfect circle (perfect circle) as shown in the figure, or a polygonal ring such as an ellipse, a square or a rectangle. Further, as will be described later, a configuration in which a part of the ring is cut off, or a shape having irregularities inside and outside the ring may be used. However, it is preferable that the shape of the first recess is similar to the end face shape of the magnetic attracting member to be opposed or the inner shape of the planar coil disposed around the magnetic attracting member. Note that the similarity in this case means that the overall shape only needs to be a similar shape regardless of differences in the corners of the rectangular shape, such as rounded corners or minute irregularities.

  As shown in FIG. 1, the portion 3 surrounded by the first recess 2 can function as a magnetic attracting member that is disposed to face the permanent magnet in the non-contact charging device or the transmission coil component used therefor. Even in such a case, the first recess 2 functions as a magnetic gap in the magnetic sheet 1, and the magnetic flux between the portion 3 surrounded by the first recess 2 and the portion outside the first recess 2 is reduced. The magnetic saturation of the flow and the outer portion of the first recess 2 due to the flow can be suppressed. Although it is possible to make the outer shape and the inner shape of the first concave portion different from each other, in the embodiment shown in FIG. 2, the outer shape and the inner shape of the first concave portion are set so that the magnetic flux is not concentrated on a specific portion. Both are round. Although it is possible to make the inner shape and the outer shape of the first recess different from each other, it is more preferable that the width of the first recess 2 is constant along the extending direction of the recess. Although the function as a magnetic gap is exhibited by forming the first recess, the width of the first recess is preferably 1 mm or more in order to enhance the function. The width is more preferably 1.5 mm or more. On the other hand, if the width of the first recess is too large, the portion that functions as the magnetic yoke is reduced. The interval is more preferably 3 mm or less.

  Since the first concave portion 2 has a bottom, leakage of the magnetic flux from the power feeding device to the rear surface side is suppressed as compared with a case where the first concave portion 2 is completely penetrated. Furthermore, in the embodiment shown in FIG. 2, the distance d1 between the bottom surface of the first recess 2 and the other main surface is smaller than the depth d2 of the first recess 2. With this configuration, the inductance and Q value are improved, and the efficiency of the transmission coil component and the non-contact charging device using the transmission coil component can be improved. When the distance d1 between the bottom surface of the first recess 2 and the other main surface is greater than the depth d2 of the first recess 2, the magnetic flux from the magnetic attracting member is surrounded by the first recess 2 3 easily flows to the sheet portion outside the first recess 2, and the sheet portion outside the first recess 2 is likely to be magnetically saturated.

  The formation method of the 1st recessed part 2 does not specifically limit this. For example, the whole may be integrally formed, or a plurality of members may be combined. In the embodiment shown in FIG. 2, the first recess 2 is opposed to the sheet-like first magnetic layer 1 a having a substantially annular opening, and the first magnetic layer 1 a, and corresponds to the opening. And a sheet-like second magnetic layer 1b having no opening. Compared with the case of forming by integral molding, the concave portion can be easily formed. The outer dimensions of the first magnetic layer 1a and the second magnetic layer 1b are the same, and are bonded so that their outer edges coincide. The second magnetic layer 1b may have an opening or a notch other than the portion corresponding to the annular opening of the first magnetic layer 1a, but as in the embodiment shown in FIG. It is more preferable to use a solid magnetic layer having no opening. When a non-magnetic layer such as an adhesive layer is interposed between the magnetic layers, such as when the first magnetic layer 1a and the second magnetic layer 1b are bonded together, the bottom surface of the first recess 2 and the other main layer The distance d1 from the surface and the depth d2 of the first recess 2 are determined by the magnetic material portion excluding the nonmagnetic material portion.

  The first magnetic layer 1a for forming the first recess 2 will be further described. The first magnetic layer 1a is composed of a sheet having the same properties except for the annular opening. For example, this applies to the case where the entire first magnetic layer 1a is taken out of the same soft magnetic alloy ribbon. In this case, the thickness of the first magnetic layer is substantially constant inside and outside the annular opening. Therefore, in the magnetic sheet 1, the surface of the portion 3 surrounded by the first recess 2 and the surface of the outer portion of the first recess 2 are on the same plane, and the height is constant. Furthermore, as described above, a magnetic attracting member disposed to face the permanent magnet can be configured by the portion 3 surrounded by the first recess 2 which is a part of the first magnetic layer. Therefore, the contactless charging device and the transmission coil component used therefor can be reduced in size through a reduction in the height of the magnetic adsorption member.

  The magnetic sheet shown in FIG. 2 is preferably used in a non-contact charging apparatus as shown in FIG. In this case, as shown in FIG. 1, when viewed from the facing direction of the magnetic attracting member 10 and the magnetic sheet 1, the facing surface of the portion 3 surrounded by the first recess is located closer to the facing surface of the magnetic attracting member 10. More preferably, it is more preferable that the portion 3 surrounded by the first recess as viewed from the facing direction includes the entire magnetic adsorption member 10 inside. According to such a configuration, it is possible to more effectively suppress the magnetic flux from the magnetic attracting member 10 from flowing outside the first recess. Further, by increasing the facing surface of the portion 3 surrounded by the first recess rather than the facing surface of the magnetic attracting member 10, the allowable amount of positional deviation between the power receiving device and the power feeding device is also increased. More preferably, the outer edge of the portion 3 surrounded by the first recess when viewed from the facing direction is larger and smaller than the outer edge of the magnetic attraction member by 1 mm or more. However, if the outer edge of the portion 3 surrounded by the first recess becomes too larger than the outer edge of the magnetic attracting member, the overlap with the coil to be placed becomes large, so that it is practically surrounded by the first recess. It is preferable to arrange the portion 3 so that the outer edge thereof is within 5 mm from the outer edge of the magnetic adsorption member.

  As the soft magnetic material used for the magnetic sheet, ferrite, a silicon steel plate, a soft magnetic alloy ribbon (hereinafter also simply referred to as a ribbon) manufactured by roll quenching, and a composite material of these with a resin can be used. In order to reduce eddy current loss and improve charge transmission efficiency, it is preferable to make the soft magnetic material thinner. In this regard, a soft magnetic alloy ribbon manufactured by roll quenching or the like is preferable. Further, according to the soft magnetic alloy ribbon, it is easy to form a substantially annular opening. Specifically, a thin film having a thickness of 50 μm or less made of an Fe-based amorphous ribbon, a Co-based amorphous ribbon, an Fe-based nanocrystalline soft magnetic alloy ribbon, a Co-based nanocrystalline soft magnetic alloy ribbon having a high saturation magnetic flux density, or the like. Use a belt. Among these, since the microcrystalline soft magnetic alloy ribbon such as the Fe-based nanocrystalline soft magnetic alloy ribbon has a high magnetic permeability, the first magnetic layer and the second magnetic layer are coated with the microcrystalline soft magnetic alloy ribbon. It is particularly preferable to configure. The thickness of one thin ribbon is more preferably 30 μm or less, and further preferably 25 μm or less. When a soft magnetic alloy ribbon manufactured by roll quenching or the like is used, each of the first magnetic layer and the second magnetic layer may be formed of a single ribbon layer, or a plurality of ribbons may be interposed via a resin or the like. These magnetic layers may be formed of a laminated body laminated in a stacked manner. By configuring the magnetic layer with a laminate, magnetic saturation is less likely to occur. When the magnetic sheet is composed of a soft magnetic alloy ribbon, it may be composed of, for example, about 2 to 30 layers. However, from the viewpoint of cost reduction, the number of thin ribbons is more preferably 10 or less. The total thickness of all soft magnetic materials used in the magnetic sheet can be 500 μm or less. In order to reduce the height, the thickness is preferably 300 μm or less.

(Second Embodiment of Magnetic Sheet)
Next, FIG. 3 shows another embodiment of the magnetic sheet according to the present invention. FIG. 3 is a cross-sectional view when the center of the planar magnetic sheet is cut in the normal direction of the main surface. The description of the same configuration as the embodiment shown in FIG. 2 is omitted. The embodiment shown in FIG. 3 is an example in which the first magnetic layer and the second magnetic layer are configured using soft magnetic alloy ribbons. The first magnetic layer 1a is formed by overlapping a plurality of soft magnetic alloy ribbons 1a (1) and 1a (2), and the second magnetic layer 1b is formed using only one soft magnetic alloy ribbon. Yes. Each soft magnetic alloy ribbon has the same thickness, but a plurality of soft magnetic alloy ribbons are overlapped to form the first magnetic layer 1a, so that the first magnetic layer 1a is formed. The thickness of the second magnetic layer 1b is reduced so that the distance between the bottom surface of the first recess 2 and the other main surface is smaller than the depth of the first recess 2. Multilayering the first magnetic layer through a resin or the like contributes to reduction of eddy current loss. In the embodiment shown in FIG. 3, the first magnetic layer 1a is composed of two layers, but it may be more. On the other hand, the second magnetic layer 1b is preferably composed of a single soft magnetic alloy ribbon sheet. When the soft magnetic alloy ribbon sheet having the same thickness is used and the thickness (total number of layers) of the first magnetic layer and the second magnetic layer is constant, the second magnetic layer is formed of one layer. However, the distance between the bottom surface of the first recess 2 and the other main surface can be minimized compared to the depth of the first recess 2.

(Third embodiment of magnetic sheet)
Next, FIG. 4 shows another embodiment of the magnetic sheet according to the present invention. FIG. 4 is a cross-sectional view when the center of the planar magnetic sheet is cut in the normal direction of the main surface. The description of the same configuration as the embodiment shown in FIG. 3 is omitted. The embodiment shown in FIG. 4 is different from the embodiment shown in FIG. 3 in that the size of the second magnetic layer 1b ′ is different from the size of the first magnetic layer 1a. In the embodiment shown in FIG. 4, the outer edge of the second magnetic layer 1b is inside the outer edge of the first magnetic layer 1a when viewed from the normal direction of the main surface of the magnetic sheet. By making the second magnetic layer smaller than the first magnetic layer, the amount of the magnetic layer used can be reduced and the cost can be reduced. The second magnetic layer 1b is thinner than the first magnetic layer 1a and has a lower strength. Therefore, by making the second magnetic layer 1b not protrude from the first magnetic layer 1a, it is possible to suppress damage such as peeling or deformation at the end of the magnetic sheet. In the embodiment shown in FIG. 4, the outer shape of the second magnetic layer is rectangular like the first magnetic layer, but need not be the same shape as the outer shape of the first magnetic layer. For example, you may make it circular according to the external shape of a 1st recessed part.

(Fourth embodiment of magnetic sheet)
Next, FIG. 5 shows another embodiment of the magnetic sheet according to the present invention. FIG. 5 is a plan view of a planar magnetic sheet as viewed from the normal direction of the main surface. The embodiment shown in FIG. 5 differs from the embodiment shown in FIG. 2 in that the first recess 2 ′ is C-shaped when viewed from the normal direction of the main surface. The description of the same configuration as the embodiment shown in FIG. 2 is omitted. A portion 3 surrounded by the first concave portion 2 and an outer portion of the first concave portion 2 ′ are connected via a connecting portion 15, and these are integrally formed. The shape of the portion 3 surrounded by the first recess 2 ′ is circular as a whole except for the portion where the connecting portion 15 is formed, but it may be oval or polygon other than circular. . The magnetic sheet 1 can be formed by integrally molding the whole, but in the embodiment shown in FIG. 5, the first recess 2 ′ has an opening as in the embodiment shown in FIG. One magnetic layer and a second magnetic layer which is opposed to the first magnetic layer and has no opening at a position corresponding to the opening. In the embodiment shown in FIG. 5, the opening of the first magnetic layer is C-shaped. Since the portion other than the C-shaped opening is formed of an integral sheet, the thickness of the first magnetic layer is substantially constant inside and outside the C-shaped opening. Therefore, in the magnetic sheet 1, the surface of the portion 3 surrounded by the first recess 2 ′ and the surface of the outer portion of the first recess 2 are on the same plane, and the height is constant. The point which can comprise the magnetic attraction member arrange | positioned facing a permanent magnet by the part 3 enclosed by 1st recessed part 2 'is the same as that of the above-mentioned embodiment. In the embodiment shown in FIG. 5, the first magnetic layer further includes a portion corresponding to the coupling portion 15, thereby reducing the number of components and reducing the height of the magnetic attracting member, and the non-contact charging device and the transmission coil used therein. Parts can be miniaturized and simplified. In addition, since the manufacturing process is simplified and the number of man-hours is reduced, the mass productivity is excellent. From the viewpoint of suppressing the flow of magnetic flux between the portion 3 surrounded by the first recess 2 ′ and the outer portion of the first recess 2 ′, the width of the connecting portion 15 is changed to the first recess 2 ′. The ratio of the enclosed portion 3 to the entire outer periphery may be 0.2 or less, more preferably 0.1 or less. On the other hand, if the width of the connecting portion is too small, it becomes difficult to form the connecting portion. Therefore, the ratio is preferably secured to 0.01 or more. In the case of a non-contact charging device, the upper limit of the absolute value of the width of the connecting portion 15 is, for example, 6 mm or less, more preferably 5 mm. The lower limit is preferably 1 mm or more. Since the first recess 2 ′ only needs to be C-shaped when viewed from the normal direction of the main surface, the connecting portion 15 may be divided by a crack or the like during or after laminating described later. I do not care. Moreover, the effect which the structure etc. which concern on the 1st recessed part shown in embodiment shown in FIGS. 2-4 exhibits is exhibited irrespective of the presence or absence of the connection part 15. FIG.

(Fifth embodiment of magnetic sheet)
Next, FIG. 6 shows another embodiment of the magnetic sheet according to the present invention. FIG. 6 is a plan view of a planar magnetic sheet as viewed from the normal direction of the main surface. The magnetic sheet shown in FIG. 6 has the same depth as the first recess 2 ′, and has a second recess 16 that communicates the first recess 2 ′ and the outer edge side of the magnetic sheet 1. FIG. Different from the embodiment shown in FIG. The description of the same configuration as that of the embodiment shown in FIG. The second concave portion 16 is arranged such that its longitudinal direction is directed toward the center of the first concave portion 2 ′. By forming the second recess 16, the first recess 2 ′ is a recess that is open in the plane direction and continues to the outer edge of the magnetic sheet 1. The case where the first recess 2 ′ is constituted by a first magnetic layer having an opening and a second magnetic layer that is opposed to the first magnetic layer and has no opening at a position corresponding to the opening. By providing the second recess 16, the following effects are exhibited. For example, when the first magnetic layer is taken out from the soft magnetic alloy ribbon, the ribbon corresponding to the first recess 2 ′ of the first magnetic layer needs to be removed. If the portion corresponding to the first recess 2 ′ is a closed opening, it is difficult to remove the ribbon at the portion. On the other hand, if the opening is open to the outer edge of the first magnetic layer, the first recess 2 connected to the outer portion is removed when the outer portion of the first magnetic layer is removed. The strip corresponding to 'can be removed at the same time, and the process can be simplified.

  The position of the second recess 16 may be a position that does not interfere with the connecting portion 15, but the second recess 16 is on the opposite side of the connecting portion 15 across the portion 3 surrounded by the first recess 2 ′. More preferably, they are arranged. For example, when the base material is peeled in one direction to take out the magnetic sheet from the base material, the base material corresponding to the opening cannot be removed smoothly if the second recess and the connecting portion are too close. In contrast, the second recess 16 can be easily removed by disposing the second recess 16 on the opposite side of the connecting portion 15 with the portion 3 surrounded by the first recess 2 'interposed therebetween. In the configuration shown in FIG. 6, the arrangement is such that the communication direction of the second recess 16 and the connection direction of the connection portion 15 are on the same straight line, that is, from the center of the portion 3 surrounded by the first recess 2 ′. The arrangement is such that the angle seen is 180 degrees. Moreover, the effect which the structure etc. which concern on the 1st recessed part shown in embodiment shown in FIGS. 2-4 exhibits is exhibited irrespective of the presence or absence of a 2nd recessed part.

  You may provide a slit further with respect to the above embodiment. For example, slits formed radially from the center of the first recess can be provided in at least the first magnetic layer. In the case of the non-contact charging apparatus as shown in FIG. 1, the magnetic flux generated by the planar coil 9 flows in the radial direction of the first magnetic layer 1. Therefore, by providing a slit radially from the center of the first recess, the magnetic flux and the longitudinal direction of the slit are substantially parallel, so that eddy current due to the magnetic flux applied by the slit 17 can be suppressed. Any slit may be used as long as it is formed in the form of a cut and inhibits eddy currents. In addition, the slit may have both ends positioned in the first magnetic layer, but the slit is easier to form in a configuration in which one end reaches the outer edge of the first magnetic layer. The number of slits is not particularly limited.

  When the magnetic sheet is constituted by lamination, each layer may be laminated using an adhesive. Furthermore, the magnetic sheet constituted by lamination or the like is preferably fixed to the reinforcing member in order to prevent breakage. Specifically, it is preferable to use a magnetic sheet obtained by laminating a soft magnetic alloy ribbon with a resin sheet or the like. A resin sheet may be provided on one of the two main surfaces of the front and back, or may be provided on both. A resin sheet other than the adhesive may be disposed between the first magnetic layer and the second magnetic layer. When a soft magnetic alloy ribbon is used for the second magnetic layer, exposure of the soft magnetic alloy ribbon is suppressed by disposing at least one of an adhesive and a resin sheet on the bottom surface of the first recess.

  In the above-described embodiment, the magnetic sheet is mainly formed by laminating the first magnetic layer and the second magnetic layer from the viewpoint of reduction in the number of parts and handling properties when used for transmission coil parts and the like. However, it is not always necessary to bond the first magnetic layer and the second magnetic layer before configuring the transmission coil component. For example, the first magnetic layer and the second magnetic layer may be prepared separately, and may be sequentially bonded when configuring the transmission coil component. In addition, when configuring a transmission coil component such as a power receiving device or a non-contact charging device, by attaching the first magnetic layer and the second magnetic layer to separate objects, and bringing them close or in contact with each other, A magnetic sheet having the form of the present invention may be configured.

  A transmission coil component was configured using a magnetic sheet having the shape shown in FIG. A microcrystalline soft magnetic alloy ribbon was used as the soft magnetic material of the magnetic sheet. As a microcrystalline soft magnetic alloy ribbon, Finemet (registered trademark) (FT3M material, thickness 18 μm) manufactured by Hitachi Metals, Ltd. was used. Various magnetic sheets (No. 2, 3, 5 to 7) having different numbers of first magnetic layers and second magnetic layers were prepared. Each ribbon was laminated by attaching a double-sided adhesive sheet (thickness 10 μm). A PET resin having a thickness of 31 μm was attached to the thin strip exposed on the uppermost surface. The outer shape of the magnetic sheet is square, and the length and width are 45 mm. The outer diameter of the first recess is 25 mm, and the inner diameter is 20 mm. The width of the connecting portion and the width of the second recess are 4 mm. For reference, a magnetic sheet (No. 1 and 4) composed of only the first magnetic layer having a C-shaped opening without providing the second magnetic layer was also prepared. The obtained laminated magnetic sheet and the planar coil were combined to constitute a power receiving side (secondary side) transmission coil component. The planar coil was constructed by winding two para wires with a wire diameter of 0.32 mm for 15 turns, and the outer shape of the coil was a rectangle of 40 × 20 mm, and the inner shape was a rectangle of 20 mm × 10 mm. On the other hand, a planar coil on the power supply side (primary side) is formed by winding a litz wire with a wire diameter of 1 mm for 20 turns (10 turns, 2 stages), the outer shape of the coil is a circle with a diameter of 40 mm, and the inner shape is a diameter of 20 mm. The round shape. Ferrite was used for the primary side magnetic sheet. A transmission coil component is configured by aligning the center of the magnetic sheet and the planar coil, and the transmission coil component on the power feeding side and the transmission coil component on the power receiving side are arranged in the same manner as in FIG. 1, and the inductance Ls and Q value are measured at 120 kHz. did. The results are shown in Table 1. The thickness of the first magnetic layer is the sum of the thicknesses of the soft magnetic alloy ribbons that are magnetic parts, and corresponds to the depth of the first recess. The thickness of the second magnetic layer is also the sum of the thicknesses of the soft magnetic alloy ribbons that are magnetic parts, and corresponds to the distance between the bottom surface of the first recess and the other main surface. Note that the distance between the bottom surface of the first recess and the other main surface and the depth of the first recess described here exclude the portion of the nonmagnetic layer such as the adhesive layer between the magnetic layers as described above. It is determined by the magnetic material.

  Looking at the results of Nos. 1 to 3 in which the total number of layers is three, the number of layers constituting the second magnetic layer is smaller, and the distance between the bottom surface of the first recess and the other main surface is the first. In the No. 2 magnetic sheet smaller than the depth of the concave portion, the number of layers constituting the second magnetic layer is larger, and the distance between the bottom surface of the first concave portion and the other main surface is smaller than that of the first concave portion. It can be seen that both Ls and Q are higher than the No. 3 magnetic sheet larger than the depth. In particular, the magnetic sheet of No. 2 is superior in Ls and Q as compared with the magnetic sheet of No. 1 in which all layers are composed of soft magnetic metal ribbon sheets having openings. Similarly, when looking at the results of No. 4 to No. 7 with the total number of layers being 4, the No. 5 magnetic sheet in which the distance between the bottom surface of the first recess and the other main surface is smaller than the depth of the first recess is The distance between the bottom surface of the first recess and the other main surface is larger than the depth of the first recess, and the distance between the bottom surface of the first recess and the other main surface is the distance between the first recess and the first main surface. Both Ls and Q are higher than the magnetic sheet of No. 6 equal to the depth. In particular, it can be seen that the magnetic sheet of No. 5 is superior in Q to the magnetic sheet of No. 4 in which all layers are composed of soft magnetic metal ribbon sheets with openings.

  When a magnetic sheet was prepared using a solid soft magnetic metal ribbon sheet with no openings in all layers, Ls was 15.3 μH in the case of 3 layers, Q was 34.8 in the case of 4 layers. Ls was 15.9 μH and Q was 33.1. That is, all of the magnetic sheets shown in Table 1 formed using a soft magnetic metal ribbon sheet having an opening were excellent in Ls and Q, and the effect of the first recess itself could be confirmed.

DESCRIPTION OF SYMBOLS 1, 8: Magnetic sheet 2: 1st recessed part 3: The part enclosed by the 1st recessed part 4, 9: Planar coil 5, 11: Board | substrate 6: Secondary battery 7: Power receiving apparatus 10: Adsorption member 12: AC power supply 13: Circuit unit 14: Power feeding device 15: Connection unit 16: Second recess

Claims (8)

A magnetic sheet for a non-contact charging device,
On one main surface side of the magnetic sheet, the first concave portion having a substantially annular shape when viewed from the normal direction of the main surface,
A magnetic sheet, wherein a distance between a bottom surface of the first recess and the other main surface is smaller than a depth of the first recess. The first recess has a first magnetic layer having a substantially annular opening;
2. The magnetic sheet according to claim 1, comprising a second magnetic layer that is opposed to the first magnetic layer and has no opening at a position corresponding to the opening. The first magnetic layer and the second magnetic layer are formed using a soft magnetic alloy ribbon,
The first magnetic layer is formed by stacking a plurality of the soft magnetic alloy ribbons,
The magnetic sheet according to claim 1 or 2, wherein the second magnetic layer is formed by using only one layer of the soft magnetic alloy ribbon. 4. The magnetic sheet according to claim 2, wherein the first recess has a C-shape when viewed from the normal direction of the main surface.   It has the same depth as the said 1st recessed part, and has a 2nd recessed part which connects the said 1st recessed part and the outer edge side of the said magnetic sheet, It is any one of Claims 2-4 characterized by the above-mentioned. The magnetic sheet described in 1.   6. The outer edge of the second magnetic layer is located inside the outer edge of the first magnetic layer when viewed from the normal direction of the main surface. 6. Magnetic sheet. A planar coil and the magnetic sheet according to any one of claims 1 to 6,
The non-contact characterized in that the magnetic sheet and the planar coil are arranged to face each other so that a portion surrounded by the first recess is located on a winding axis of the planar coil. Transmission coil parts for charging equipment. A non-contact charging device for transmitting power between the transmission coil parts by facing two transmission coil parts,
One of the transmission coil components is the coil component according to claim 7,
The other of the transmission coil components has a planar coil and a magnetic adsorption member disposed inside the planar coil,
The non-contact charging apparatus, wherein the magnetic adsorption member and a portion surrounded by the first recess are arranged to face each other.

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