Multilayer magnetic sheet

Abstract

To provide a magnetic sheet, a rolled magnetic sheet, and a multilayer magnetic sheet that can prevent small pieces from falling off.SOLUTION: A magnetic sheet 100 includes a support 11 formed in a band shape, and an adhesive layer 10 having an adhesive 12 provided on at least one of a first surface 11A and a second surface 11B of the support 11, and a magnetic ribbon 20 formed into a belt shape using a magnetic material and adhered to the adhesive 12 of the adhesive layer 10, and when the dimension of the adhesive layer 10 in a direction intersecting the longitudinal direction of the adhesive layer 10 is a width A, and the dimension of the magnetic ribbon 20 in a direction intersecting the longitudinal direction of the magnetic ribbon 20 is a width B, the relationship 0.2 mm≤(width A-width B)≤3 mm is satisfied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to magnetic sheets, wound magnetic sheets, and multilayer magnetic sheets used for magnetic cores, inductors, magnetic shields, and the like.

Background Art

[0002] In recent years, non-contact charging that provides charging by power transmission using electromagnetic induction, with transmission coils provided on both the power supply side and the power reception side, has attracted attention. In non-contact charging, power supply is performed by generating an electromotive force in the secondary transmission coil of the power reception device through the magnetic flux generated in the primary transmission coil of the power supply device via the casings of the power supply device and the power reception device.

[0003] Non-contact charging has begun to spread to electronic devices such as tablet-type information terminals, music players, smartphones, and mobile phones. In addition, non-contact charging is a technology applicable to electronic devices other than those described above, electric vehicles, and drones. It is also a technology applicable to transport vehicles such as forklifts and AGVs (Automated Guided Vehicles), railways, and streetcars.

[0004] In order to increase the power transmission efficiency in non-contact charging, a magnetic sheet may be installed as a coil yoke on the side opposite to the contact surface between the power supply device and the power reception device in the transmission coil. The magnetic sheet arranged in this way has roles such as a magnetic shielding material for preventing magnetic flux leakage during charging and a yoke member for refluxing the magnetic flux generated in the coil during charging.

[0005] As methods for manufacturing the above-described magnetic sheet, various methods have been proposed (see, for example, Patent Documents 1 to 3). Patent Documents 1 to 3 disclose manufacturing methods including a step of dividing a plurality of thin plate-like magnetic bodies, amorphous alloys, or ribbons of nanocrystalline grain alloys (hereinafter also referred to as "alloy ribbons") contained in the magnetic sheet for the purpose of improving the Q value or reducing eddy current loss.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2008-112830 [Patent Document 2] Special Publication No. 2015-505166 [Patent Document 3] International Publication No. 2020-235642 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the manufacturing methods described in the above-mentioned Patent Documents 1 to 3, the divided pieces of the alloy strip are adhered to and held in place by an adhesive layer provided on the magnetic sheet. However, if there are pieces that are not adhered to the adhesive layer, there is a risk that these pieces will fall off the magnetic sheet, which is a problem.

[0008] This disclosure provides a magnetic sheet, a rolled magnetic sheet, and a multilayer magnetic sheet that can suppress the shedding of small pieces. [Means for solving the problem]

[0009] A magnetic sheet according to a first aspect of the present disclosure is a magnetic sheet comprising: a support formed in the shape of a strip; an adhesive layer having an adhesive provided on at least one of a first surface and a second surface of the support; and a magnetic strip formed in the shape of a strip using a magnetic material, the magnetic strip being adhered to the adhesive of the adhesive layer, wherein the relationship 0.2 mm ≤ (width A - width B) ≤ 3 mm is satisfied when the dimensions of the adhesive layer in a direction intersecting the longitudinal direction of the adhesive layer are width A, and the dimensions of the magnetic strip in a direction intersecting the longitudinal direction of the magnetic strip are width B.

[0010] The rolled magnetic sheet according to the second aspect of this disclosure is formed by winding the magnetic sheet according to the first aspect in a ring shape or a spiral shape.

[0011] A multilayer magnetic sheet according to a third aspect of the present disclosure comprises a support formed in the shape of a strip, a plurality of adhesive layers having an adhesive provided on a first surface and a second surface of the support, a plurality of magnetic strips formed in the shape of a strip using a magnetic material, each of which is arranged between adjacent adhesive layers and adhered to the adhesive of the adhesive layers, and satisfies the relationship 0.2 mm ≤ (width A - width B) ≤ 3 mm, where the dimension of the adhesive layer in the direction intersecting the longitudinal direction of the adhesive layer is width A, and the dimension of the magnetic strip in the direction intersecting the longitudinal direction of the magnetic strip is width B.

[0012] According to the magnetic sheet according to the first aspect of this disclosure, the rolled magnetic sheet according to the second aspect, and the multilayer magnetic sheet according to the third aspect, the width A of the adhesive layer in the adhesive layer is wider than the width B of the magnetic strip. When attaching the magnetic strip to the adhesive layer, even if meandering occurs in the adhesive layer or the magnetic strip, the adhesive of the adhesive layer is more likely to be distributed over the entire surface of the magnetic strip.

[0013] By setting the difference between width A and width B to 0.2 mm or more, it is easier to prevent areas where adhesive is not present on the magnetic strip when attaching the magnetic strip to the adhesive layer. By setting the difference between width A and width B to 3 mm or less, it is easier to prevent large areas where magnetic strips are not present on the magnetic sheet. In addition, it is easier to prevent large gaps between magnetic strips (magnetic gaps) when magnetic sheets are arranged in parallel. [Effects of the Invention]

[0014] The magnetic sheet, rolled magnetic sheet, and multilayer magnetic sheet of this disclosure make it easier to arrange the adhesive of the adhesive layer over the entire surface of the magnetic strip, which has the effect of making it easier to suppress the detachment of small pieces formed by breaking the alloy strip. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view taken in the width direction to illustrate the structure of the magnetic sheet in this disclosure. [Figure 2]It is a cross-sectional view explaining another example of the region where the adhesive is provided. [Figure 3] It is a schematic diagram explaining the shape of the roll-shaped magnetic sheet. [Figure 4] It is a cross-sectional view explaining the configuration of the multilayer magnetic sheet. [Figure 5] It is a cross-sectional view explaining another configuration of the multilayer magnetic sheet. [Figure 6] It is a cross-sectional view explaining the configuration of the multilayer magnetic sheet with different numbers of layers. [Figure 7] It is a schematic diagram explaining the manufacturing method of the magnetic sheet and the roll-shaped magnetic sheet. [Figure 8] It is a cross-sectional view explaining the configuration of the laminate supplied from the first unwind roll. [Figure 9] It is a cross-sectional view explaining the configuration of the laminate supplied from the first unwind roll and from which the resin sheet has been peeled off. [Figure 10] It is a cross-sectional view explaining the configuration of the magnetic thin strip supplied from the second unwind roll. [Figure 11] It is a cross-sectional view explaining the state in which the magnetic thin strip is adhered to the adhesive layer by the pasting roll. [Figure 12] It is a cross-sectional view explaining the state in which cracks are formed in the magnetic thin strip by the crack roll. [Figure 13] It is a schematic diagram explaining the manufacturing method of the multilayer magnetic sheet. [Figure 14] It is a schematic diagram explaining the manufacturing method of the multilayer magnetic sheet.

Embodiments for Carrying Out the Invention

[0016] Regarding the magnetic sheet 100, roll-shaped magnetic sheet 200, multilayer magnetic sheet 300, and multilayer magnetic sheet 300T according to an embodiment of this disclosure, they will be described while referring to FIGS. 1 to 14. The magnetic sheet 100, roll-shaped magnetic sheet 200, multilayer magnetic sheet 300, and multilayer magnetic sheet 300T according to an embodiment are used in non-contact charging devices. They may be used in the power supply device of the charging device or in the power receiving device.

[0017] The multilayer magnetic sheet 300 has a structure in which multiple magnetic sheets 100 are laminated. The rolled magnetic sheet 200 has a shape in which the magnetic sheets 100 are wound. In this embodiment, the multilayer magnetic sheet 300 and the multilayer magnetic sheet 300T will be described in an example in which they are used for contactless charging of devices that have a higher power consumption than information processing devices and electronic devices such as smartphones.

[0018] For example, the explanation will be applied to an example where the multilayer magnetic sheet 300T is used for contactless charging of mobile devices such as automobiles. Note that the multilayer magnetic sheet 300, the multilayer magnetic sheet 300T, and the magnetic sheet 100 may also be used for contactless charging of information processing equipment and electronic devices.

[0019] Figure 1 is a cross-sectional view of the magnetic sheet 100, cut in the width direction, illustrating its structure. The magnetic sheet 100 is a sheet that constitutes the rolled magnetic sheet 200, the multilayer magnetic sheet 300, and the multilayer magnetic sheet 300T. As shown in Figure 1, the magnetic sheet 100 has a structure in which one adhesive layer 10, one resin sheet 15, and one magnetic strip 20 are laminated together.

[0020] The adhesive layer 10 is a component to which the magnetic strip 20 is attached. The adhesive layer 10 is a component formed in a long shape, for example, a rectangular film-like component. The adhesive layer 10 mainly consists of a support 11 and an adhesive 12.

[0021] The support 11 is a long, strip-shaped membrane member, for example, a rectangular membrane member. The support 11 is formed using a flexible resin material. Polyethylene terephthalate (PET) can be used as the resin material.

[0022] The adhesive 12 is provided in a film or layer form on the first surface 11A and the second surface 11B of the support 11. In this embodiment, the explanation will be applied to an example where the first surface 11A is the surface of the film-like support 11 facing the magnetic strip 20, and the second surface 11B is the surface opposite to the first surface 11A.

[0023] The adhesive 12 can be, for example, a pressure-sensitive adhesive. For example, known adhesives such as acrylic adhesives, silicone adhesives, urethane adhesives, synthetic rubber, and natural rubber can be used as the adhesive 12. Acrylic adhesives are preferred as the adhesive 12 because they have excellent heat resistance and moisture resistance, and can bond to a wide range of materials.

[0024] The adhesive 12 is provided in layers on the first surface 11A and the second surface 11B of the support 11. In this embodiment, the explanation will be applied to an example in which the adhesive 12 is provided on the entire surface of the first surface 11A and the second surface 11B of the support 11.

[0025] Figure 2 is a cross-sectional view illustrating another example of the region where the adhesive 12 is provided. Furthermore, the areas on the first surface 11A and the second surface 11B of the support 11 where the adhesive 12 is applied do not have to be the entire surface of the first surface 11A and the second surface 11B, as shown in Figure 2. Specifically, the adhesive 12 does not have to be applied to the edges in the width direction of the first surface 11A and the second surface 11B.

[0026] Furthermore, the first surface 11A may not be the surface facing the magnetic strip 20, but rather the second surface 11B may be the surface facing the magnetic strip 20. Also, the adhesive 12 may be provided only on the surface of the support 11 that faces the magnetic strip 20, of the first surface 11A and the second surface 11B.

[0027] As shown in Figure 1, the resin sheet 15 is a film-like component formed using resin, and is also referred to as a protective film, release film, or liner. The resin sheet 15 is a component used to protect the magnetic sheet 100 (including rolled magnetic sheets 200 and multilayer magnetic sheets 300).

[0028] The resin sheet 15 has the function of suppressing the unnecessary increase of cracks 21 (or cracks that connect multiple cracks 21 in a mesh-like manner) that occur when unintended external forces are applied to the magnetic tape 20. It also has the function of suppressing the detachment of small pieces 22 of the magnetic tape 20 and suppressing the rusting of the magnetic tape 20.

[0029] Furthermore, the resin sheet 15 has the function of suppressing unwanted deformation when processing the magnetic sheet 100 (including rolled magnetic sheets 200 and multilayer magnetic sheets 300) into a predetermined shape. Examples of unwanted deformation include surface irregularities. The resin sheet 15 may be laminated together with the adhesive layer 10 as described above, or it may be laminated on its own.

[0030] The resin sheet 15 is preferably a film-like member formed using resin, and more preferably a member formed using an elastic resin. When the resin sheet 15 is a member formed using resin, the elastic force of the resin sheet 15 makes it easier to suppress the occurrence of irregularities on the surface of the magnetic strip 20.

[0031] Even if irregularities occur on the surface of the magnetic tape 20, the elastic force of the resin sheet 15 makes it easier to flatten the irregularities of the magnetic tape 20. The planar state of the magnetic tape 20 can be made to a good state with few irregularities. The change in magnetic properties of the magnetic sheet 100 over time is easily reduced.

[0032] The resin sheet 15 can be made of a resin with a lower limit of tensile modulus of 0.1 GPa. If the tensile modulus of the resin is 0.1 GPa or higher, the above effects are more easily obtained. The lower limit of the tensile modulus is preferably 0.5 GPa, and more preferably 1.0 GPa.

[0033] The upper limit of the tensile modulus of the resin is preferably 10 GPa. If it exceeds 10 GPa, it may suppress the deformation of the alloy strip when forming the crack 21 described later. The upper limit of the tensile modulus is preferably 9 GPa, and more preferably 8 GPa.

[0034] Preferably, the resin sheet 15 has a thickness of 1 μm or more and 100 μm or less. If the thickness of the resin sheet 15 increases, the magnetic sheet 100 becomes less deformable. It may become difficult to arrange the magnetic sheet 100 to conform to a curved or bent surface.

[0035] If the thickness of the resin sheet 15 is less than 1 μm, the resin sheet 15 will deform easily. This makes the resin sheet 15 difficult to handle, and the function of supporting the magnetic strip 20 by the resin sheet 15 may not be sufficiently obtained. If the resin sheet 15 is a protective film, the strength of the resin sheet 15 will be weakened, and the function of protecting the magnetic strip 20 and the like may not be sufficient.

[0036] The resin sheet 15 can be made from, for example, polyethylene terephthalate (PET), polyimide, polyetherimide, polyethylene naphthalate, polypropylene, polyethylene, polystyrene, polycarbonate, polysulfone, polyetherketone, polyvinyl chloride, polyvinyl alcohol, fluororesin, acrylic resin, cellulose, etc. From the viewpoint of heat resistance and dielectric loss, polyamide and polyimide are particularly preferred as resins for forming the resin sheet 15.

[0037] The magnetic strip 20 is a thin strip formed in a long, strip-like shape using a magnetic material. Cracks 21 are formed in the magnetic strip 20. The magnetic strip 20 is divided into a plurality of small pieces 22 by the cracks 21. In other words, the magnetic strip 20 contains a plurality of small pieces 22. The cracks 21 refer to magnetic gaps formed in the magnetic strip 20, and include, for example, cracks and / or fissures in the magnetic strip 20.

[0038] By forming cracks 21 in the magnetic strip 20, it becomes easier to improve the Q value when the magnetic sheet 100 is used as a magnetic material for an inductor. Furthermore, when the magnetic sheet 100 is used as a magnetic material for magnetic shielding, it becomes easier to reduce eddy current losses by interrupting the current path in the magnetic strip 20.

[0039] As the material for forming the magnetic thin strip 20, an alloy with an Fe-based or Co-based alloy composition can be used, and a nanocrystalline alloy or an amorphous alloy can be used. The magnetic thin strip 20 is preferably a thin strip formed from a nanocrystalline alloy (hereinafter also referred to as a "nanocrystalline alloy thin strip").

[0040] As the nanocrystalline alloy strip, a nanocrystalline alloy strip obtained by performing a nanocrystallization heat treatment on an amorphous alloy strip capable of nanocrystallization can be used. During the nanocrystallization heat treatment, it is preferable to perform the nanocrystallization heat treatment while tension is applied to the amorphous alloy strip capable of nanocrystallization. A strip formed from an amorphous alloy is also referred to as an amorphous alloy strip or an amorphous alloy strip.

[0041] The nanocrystalline alloy strip preferably has a composition represented by the following general formula. General formula: (Fe 1-a Ma) 100-x-y-z-α-β-γ Cu x Si y B z M' α M" β X γ (atom%)

[0042] In the above general formula, M is Co and / or Ni, M' is at least one element selected from the group consisting of Nb, Mo, Ta, Ti, Zr, Hf, V, Cr, Mn, and W, M'' is at least one element selected from the group consisting of Al, platinum group elements, Sc, rare earth elements, Zn, Sn, and Re, X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be, and As, and a, x, y, z, α, β, and γ satisfy 0≦a≦0.5, 0.1≦x≦3, 0≦y≦30, 0≦z≦25, 5≦y+z≦30, 0≦α≦20, 0≦β≦20, and 0≦γ≦20, respectively. Preferably, in the above general formula, a, x, y, z, α, β, and γ are 0≦a≦0.1, 0.7≦x≦1.3, 12≦y≦17, 5≦z≦10, 1.5≦α≦5, 0≦β≦1, and 0≦γ≦1, respectively.

[0043] In this embodiment, the magnetic ribbon 20 is described using an example of a ribbon (FT-3, manufactured by Hitachi Metals, Ltd.) that is an Fe-Cu-Nb-Si-B nanocrystalline alloy. Note that the magnetic ribbon 20 may also be a nanocrystalline alloy ribbon having a different composition represented by the above general formula, or it may be an amorphous alloy ribbon.

[0044] When the magnetic ribbon 20 is a nanocrystalline alloy ribbon, it is mechanically more brittle than when the magnetic ribbon 20 is an amorphous alloy ribbon. When the magnetic ribbon 20 is a nanocrystalline alloy ribbon, a small external force is required to form a crack 21 when an external force is applied directly to the magnetic ribbon 20.

[0045] When the magnetic ribbon 20 is a nanocrystalline alloy ribbon, cracks 21 can be formed on the surface of the magnetic ribbon 20 without substantially creating irregularities. Therefore, the planar state of the magnetic ribbon 20 can be maintained in good condition. The change in the shape of the magnetic ribbon 20 over time that occurs after the magnetic ribbon 20 and the adhesive layer 10 are bonded together to form a magnetic sheet 100 is reduced. The change in magnetic properties over time in the magnetic sheet 100 and the magnetic ribbon 20 can be suppressed.

[0046] As the magnetic strip 20, for example, an alloy strip with a thickness of 100 μm or less, manufactured by roll quenching, can be used. The thickness of the magnetic strip 20 is preferably 50 μm or less, more preferably 30 μm or less, more preferably 25 μm or less, and particularly preferably 20 μm or less. Furthermore, since a thin magnetic strip 20 is difficult to handle, the thickness of the magnetic strip 20 is preferably 5 μm or more, and more preferably 10 μm or more.

[0047] The magnetic strip 20 is adhered to the adhesive 12 of the adhesive layer 10. In this embodiment, the magnetic strip 20 is adhered to the adhesive 12 provided on the first surface 11A of the adhesive layer 10. Furthermore, the magnetic strip 20 and the adhesive layer 10 have a shape that satisfies the following relationship.

[0048] 0.2mm≦(Width A-Width B)≦3mm Width A is a dimension relating to the adhesive layer 10, and more preferably a dimension relating to the region of the adhesive layer 10 to which the magnetic strip 20 is adhered, where the adhesive 12 is provided. Width B is a dimension relating to the magnetic strip 20. If the adhesive 12 is provided over the entire surface of the support 11 of the adhesive layer 10, then width A is a dimension relating to the adhesive layer 10 or the support 11.

[0049] Here, the lower limit of (width A - width B) is preferably 0.5 mm, and more preferably 1.0 mm. Also, the upper limit of (width A - width B) is preferably 2.5 mm, and more preferably 2.0 mm.

[0050] Furthermore, the magnetic thin strip 20 and the adhesive layer 10 are arranged to satisfy the following relationship. 0mm < gap a, and 0mm < gap b

[0051] Gap a and gap b are the distances from the edge of the adhesive layer 10 to the edge of the magnetic tape 20. Specifically, gap a is the distance from the first adhesive layer edge 10X of the adhesive layer 10 to the first tape edge 20X of the magnetic tape 20. Gap b is the distance from the second adhesive layer edge 10Y of the adhesive layer 10 to the second tape edge 20Y of the magnetic tape 20.

[0052] The first thin band end 20X is the end on the same side as the first adhesive layer end 10X in the magnetic thin band 20. The second adhesive layer end 10Y is the end of the adhesive layer 10 opposite to the first adhesive layer end 10X. The second thin band end 20Y is the end on the same side as the second adhesive layer end 10Y in the magnetic thin band 20.

[0053] Width A, width B, gap a, and gap b are dimensions in a direction intersecting, more preferably perpendicular to, the longitudinal direction of the magnetic sheet 100. The longitudinal direction of the magnetic sheet 100 and the longitudinal direction of the adhesive layer 10 are the same direction. Also, the longitudinal direction of the magnetic sheet 100 and the longitudinal direction of the magnetic strip 20 are the same direction.

[0054] In this embodiment, the explanation will be applied to an example where the length of the magnetic tape 20 in the longitudinal direction is 20,000 m. Furthermore, the explanation will be applied to an example where the width A, which is a dimension relating to the adhesive layer 10 or support 11, is 32 mm, the width B, which is a dimension relating to the magnetic tape 20, is 30 mm, and the difference between width A and width B is 2 mm.

[0055] The longitudinal length of the magnetic sheet 100 can be, for example, 20,000 m. The width of the magnetic sheet 100 can be, for example, 32 mm. The longitudinal length of the magnetic sheet 100 may be longer or shorter than 20,000 m. The width of the magnetic sheet 100 may be wider or narrower than 32 mm. The longitudinal length of the magnetic sheet 100 may be set to a desired length depending on the application. For example, it may be cut to the required length, such as 100 mm, 300 mm, or 1000 mm.

[0056] Figure 3 is a schematic diagram illustrating the shape of the rolled magnetic sheet in this embodiment. The rolled magnetic sheet 200 has a shape formed by winding a long, strip-shaped magnetic sheet 100 into a ring or spiral shape, as shown in Figure 3. The rolled magnetic sheet 200, in which the magnetic sheet 100 is wound into a ring or spiral shape, has a cylindrical outer shape.

[0057] The longitudinal length of the rolled magnetic sheet 200 can be, for example, 20,000 m. The width of the rolled magnetic sheet 200 can be, for example, 32 mm. The longitudinal length of the rolled magnetic sheet 200 may be longer or shorter than 20,000 m. The width of the rolled magnetic sheet 200 may be wider or narrower than 32 mm.

[0058] By forming the magnetic sheet 200 into a roll, the handling of the long magnetic sheet 100 becomes easier. For example, this is effective when moving, storing, or unwinding the long magnetic sheet 100 for processing (cutting or punching). Furthermore, when constructing the rolled magnetic sheet 200, it may be constructed by winding the magnetic sheet around an annular core.

[0059] Figure 4 is a cross-sectional view illustrating the configuration of the multilayer magnetic sheet 300 of this embodiment. The multilayer magnetic sheet 300 shown in Figure 4 has a multilayer structure in which five magnetic strips 20, six adhesive layers 10, and two resin sheets 15 are laminated together. The resin sheets 15 may be a release film or a protective film.

[0060] The multilayer magnetic sheet 300 has a structure in which at least magnetic strips 20 and adhesive layers 10 are alternately laminated. In addition, resin sheets 15 are arranged at the first laminated end 301 and the second laminated end 302, which are the ends of the multilayer magnetic sheet 300 in the lamination direction.

[0061] Specifically, the structure is such that, starting from the bottom and moving upwards in Figure 4, a resin sheet 15, an adhesive layer 10, a magnetic strip 20, an adhesive layer 10, a magnetic strip 20, an adhesive layer 10, a magnetic strip 20, an adhesive layer 10, a magnetic strip 20, an adhesive layer 10, a magnetic strip 20, an adhesive layer 10, and a resin sheet 15 are stacked in that order.

[0062] As shown in Figure 4, the multilayer magnetic sheet 300 may have a multilayer structure having at least 5 layers of magnetic thin strips 20, or a multilayer structure having 2 to 4 layers of magnetic thin strips 20. It may also have a multilayer structure having 6 or more layers of magnetic thin strips 20. The number of layers in the multilayer structure can be determined as needed. Preferably, it is 3 or more layers, more preferably 4 or more layers, and more preferably 5 or more layers.

[0063] Figure 5 is a cross-sectional view illustrating other components of the multilayer magnetic sheet 300. As shown in Figure 4, the multilayer magnetic sheet 300 may be laminated with five magnetic strips 20 arranged at the same position in the width direction, or as shown in Figure 5, the magnetic strips may be arranged at different positions in the width direction.

[0064] Even when five layers of magnetic strips 20 are stacked as shown in Figure 5, it is preferable that the relationships 0 mm < gap a and 0 mm < gap b are satisfied between adjacent magnetic strips 20 and the adhesive layer 10.

[0065] When the multilayer magnetic sheet 300 has the configuration shown in Figure 5, the positions of the cracks 21 in the five layers of magnetic thin bands 20 are less likely to coincide. Therefore, it is easier to make the magnetic gap in the multilayer magnetic sheet 300 uniform.

[0066] Furthermore, when processing a multilayer magnetic sheet 300 having the configuration shown in Figure 5 by punching or cutting it into a desired shape, it is easier to suppress fluctuations in magnetic permeability depending on the processing location. Therefore, it is easier to manufacture a multilayer magnetic sheet 300 with stable shielding characteristics.

[0067] The longitudinal length of the multilayer magnetic sheet 300 can be, for example, 20,000 m. The width of the multilayer magnetic sheet 300 can be, for example, 32.5 mm. This width of 32.5 mm is an example given when a multilayer magnetic sheet 300 is constructed using a magnetic sheet 100 with a width of 32 mm, as shown in Figure 5. The longitudinal length of the multilayer magnetic sheet 300 may be longer or shorter than 20,000 m. The width of the multilayer magnetic sheet 300 may be wider or narrower than 32.5 mm. The longitudinal length of the multilayer magnetic sheet 300 may be set to a desired length depending on the application. For example, it may be cut to the required length, such as 100 mm, 300 mm, or 1000 mm.

[0068] Figure 6 is a cross-sectional view illustrating the configuration of multilayer magnetic sheets 300T with different numbers of layers. As shown in Figure 6, the multilayer magnetic sheet 300T may have a multilayer structure having more than 10 magnetic strips 20. For example, it may have a multilayer structure having 25 to 80 magnetic strips 20. It may also have a multilayer structure having more than 80 magnetic strips 20. This multilayer magnetic sheet 300T is a preferred structure example for multilayer magnetic sheets with a large number of layers. This multilayer magnetic sheet 300T facilitates the manufacture of multilayer magnetic sheets with a large number of layers.

[0069] The multilayer magnetic sheet 300T has a laminated structure in which one or more adhesive layers 10 are arranged between adjacent magnetic strips 20. In this embodiment, the example of a laminated structure in which one or two adhesive layers 10 are arranged between adjacent magnetic strips 20 will be described. In addition, resin sheets 15 are arranged at the first laminated end 301 and the second laminated end 302, which are both ends in the lamination direction of the multilayer magnetic sheet 300T.

[0070] Furthermore, the resin sheet 15 does not necessarily have to be laminated on the first laminated end 301 or the second laminated end 302. The magnetic strip 20 may be exposed, or, for example, an amorphous alloy strip, a nanocrystalline alloy strip, or other magnetic material, such as a metal foil made of aluminum, or a resin sheet may be attached to the first laminated end 301 or the second laminated end 302.

[0071] In Figure 6, one layer of adhesive layer 10 is placed between five adjacent magnetic strips 20, counting from the resin sheet 15. Two layers of adhesive layer 10 are placed between the sixth adjacent magnetic strip 20, counting from the resin sheet 15. Subsequently, one layer of adhesive layer 10 and two layers of adhesive layer 10 are placed in the same pattern. In other parts, there may be two layers of adhesive layer 10. Furthermore, there may be three or more layers of adhesive layer 10, but since the overall thickness increases, two layers or less is preferred.

[0072] The longitudinal length of the multilayer magnetic sheet 300T can be, for example, a predetermined length of 100 mm or more and 1000 mm or less. The width of the multilayer magnetic sheet 300T can be, for example, 32.5 mm. The longitudinal length of the multilayer magnetic sheet 300T may be longer or shorter than the predetermined length of 100 mm or more and 1000 mm or less. The width of the multilayer magnetic sheet 300T may be wider or narrower than 32.5 mm.

[0073] Next, the manufacturing methods for the magnetic sheet 100, the rolled magnetic sheet 200, the multilayer magnetic sheet 300, and the multilayer magnetic sheet 300T of this embodiment will be described with reference to Figures 7 to 14. First, the manufacturing methods for the magnetic sheet 100 and the rolled magnetic sheet 200 will be described.

[0074] Figure 7 is a schematic diagram illustrating the manufacturing methods of the magnetic sheet 100 and the rolled magnetic sheet 200. The magnetic sheet 100 and the rolled magnetic sheet 200 are manufactured using the manufacturing apparatus 500 shown in Figure 7. The manufacturing apparatus 500 is mainly equipped with a first unwinding roll 510, a first winding roll 520, a second unwinding roll 530, a bonding roll 540, a cracking roll 550, a flattening roll 560, and a third winding roll 570, arranged from upstream to downstream in the manufacturing process. The manufacturing apparatus 500 may also be equipped with a number of guide rolls 580. Note that the guide rolls 580 can be placed in positions not shown as needed.

[0075] Figure 8 is a cross-sectional view illustrating the structure of the laminate supplied from the first unwinding roll 510. As shown in Figure 8, a laminate is wound around the first unwinding roll 510, in which resin sheets 15 are laminated on the first surface 11A and the second surface 11B of the adhesive layer 10. The resin sheet 15 on the first surface 11A is a protective sheet, and the resin sheet 15 on the second surface 11B is also referred to as a liner. The resin sheet 15 on the first surface 11A is thinner than the resin sheet 15 on the second surface 11B.

[0076] Figure 9 is a cross-sectional view illustrating the structure of the laminate from which the resin sheet 15 has been peeled off after being supplied from the first unwinding roll 510. As shown in Figure 9, the laminate unwound from the first unwinding roll 510 has the resin sheet 15 positioned on the first surface 11A peeled off. As shown in Figure 7, the peeled resin sheet 15 is wound onto the first winding roll 520.

[0077] Figure 10 is a cross-sectional view illustrating the configuration of the magnetic strip 20 supplied from the second unwinding roll 530. The laminate from which the resin sheet 15, positioned on the first surface 11A, has been peeled off is guided to the adhesive roll 540 by a plurality of guide rolls 580. The adhesive roll 540 is further guided to the magnetic strip 20 unwound from the second unwinding roll 530. As shown in Figure 10, no cracks 21 are formed in the magnetic strip 20 guided to the adhesive roll 540.

[0078] Here, we will describe a method for manufacturing the magnetic strip 20 unwound from the second unwinding roll 530. For example, we will describe the case where the magnetic strip 20 is a nanocrystalline alloy. The magnetic strip 20 is manufactured by a manufacturing method that includes a step of rapidly cooling the molten alloy to obtain an amorphous alloy strip that can undergo nanocrystallization, and a heat treatment step of heat-treating this amorphous alloy strip at a temperature above the crystallization start temperature to form fine crystal grains.

[0079] The rapid cooling described above is performed by a single-roll method, in which molten metal is discharged onto a rotating cooling roll and rapidly cooled and solidified. The magnetic strip 20 has a long shape, with its longitudinal direction aligned with the rotation direction of the cooling roll. The longitudinal length of the magnetic strip 20 can be, for example, 20,000 m.

[0080] The heat treatment temperature described above varies depending on the alloy composition, but is generally 450°C or higher. The fine crystal grains are, for example, Fe in a body-centered cubic lattice structure with Si in solid solution. These fine crystal grains can be analyzed using X-ray diffraction and transmission electron microscopy.

[0081] In nanocrystalline alloys, at least 50% by volume consists of fine crystalline grains with an average particle size of 100 nm or less, as measured at the maximum dimension. Furthermore, the portion of the nanocrystalline alloy other than the fine crystalline grains is mainly amorphous. The proportion of fine crystalline grains may be substantially 100% by volume.

[0082] Figure 11 is a cross-sectional view illustrating the state in which the magnetic strip 20 is adhered to the adhesive layer 10 by the adhesive roll 540. As shown in Figure 7, the adhesive roll 540 presses the magnetic strip 20 against the laminate from which the resin sheet 15 has been peeled off, thereby bonding them. Specifically, the laminate and the magnetic strip 20 are guided between two opposing rolls, and the two rolls are used to press the magnetic strip 20 against the first surface 11A of the adhesive layer 10, as shown in Figure 11, thereby bonding them.

[0083] The magnetic strip 20 may be positioned so that its center coincides with the adhesive layer 10 in the width direction, or it may be positioned with its center separated from it. In this case, it is positioned so as to satisfy the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1). The laminate to which the magnetic strip 20 is bonded is guided from the bonding roll 540 to the crack roll 550, as shown in Figure 7.

[0084] Figure 12 is a cross-sectional view illustrating the state in which cracks 21 have been formed in the magnetic tape 20 by the crack roll 550. The crack roll 550 forms cracks 21 in the magnetic strip 20 bonded to the adhesive layer 10. Specifically, the laminate to which the magnetic strip 20 is bonded is guided between two opposing rolls, and the roll with the protrusion is pressed against the magnetic strip 20 to form cracks 21 as shown in Figure 12.

[0085] Of the two rolls, the one without the protrusion is positioned on the laminate side from which the resin sheet 15 has been peeled off. The magnetic strip 20, in which the crack 21 is formed, contains several small pieces 22. These several small pieces 22 are adhered to the adhesive layer 10.

[0086] The structure of the crack roll 550 will now be described. The crack roll 550 is a roll with multiple convex members arranged on its circumferential surface. The ends of the convex members of the crack roll 550 may be flat, conical, inverted conical with a central depression, or cylindrical. The multiple convex members may be arranged regularly or irregularly.

[0087] By pressing a long magnetic strip 20 against a crack roll 550, or by passing a long magnetic strip 20 between two crack rolls 550, cracks 21 are continuously formed in the magnetic strip 20. In addition, the convex members of the crack roll 550 are pressed against multiple locations on the surface of the magnetic strip 20, forming multiple cracks 21 in the magnetic strip 20.

[0088] In forming cracks using the crack roll 550, it is preferable to further form cracks that connect multiple cracks 21 in a mesh-like manner. Specifically, it is preferable to have a step of forming multiple cracks 21 by pressing the crack roll 550 against the magnetic thin strip 20, and then forming cracks that connect the multiple cracks 21 in a mesh-like manner.

[0089] For example, after applying an external force directly to the magnetic tape 20 using a crack roll 550 to form cracks 21, a second external force may be applied by means of bending or winding the magnetic tape 20 to form cracks that connect multiple cracks 21 in a mesh-like manner. The cracks connecting the cracks 21 (magnetic gaps connecting the cracks) are formed with the cracks 21 as the starting points for brittle fracture and / or crack fracture.

[0090] In the process of forming a network of cracks connecting multiple cracks 21, it is not necessary to apply the second external force described above. If the second external force is not applied, a network of cracks connecting multiple cracks 21 will be formed during the process of forming the multiple cracks 21.

[0091] The laminate, guided from the crack roll 550 to the flattening roll 560, is then flattened by the flattening roll 560. The flattening roll 560 is also referred to as the shaping roll.

[0092] Specifically, the laminate is guided between two opposing rolls in the flattening roll 560, and the laminate is pressed between the two rollers. This flattens the surface of the magnetic strip 20 on which the crack 21 is formed.

[0093] The laminated material after the planarization process becomes a magnetic sheet 100. The magnetic sheet 100 is guided to the third winding roll 570 via the guide roll 580. The magnetic sheet 100 is wound onto the third winding roll 570. The magnetic sheet 100 wound onto the third winding roll 570 and in a ring-shaped or spiral shape is a wound magnetic sheet 200.

[0094] Figure 13 is a schematic diagram illustrating the manufacturing method of the multilayer magnetic sheet 300. The multilayer magnetic sheet 300 is manufactured using the manufacturing apparatus 600 shown in Figure 13. Figure 13 shows the manufacturing apparatus 600 for manufacturing a multilayer magnetic sheet 300 containing five layers of magnetic strips 20.

[0095] The manufacturing apparatus 600 is mainly equipped with a supply roll 601, a resin sheet winding roll 602, a first magnetic sheet unwinding roll 611, a first winding roll 612, a first adhesive roll 613, a second magnetic sheet unwinding roll 621, a second winding roll 622, a second adhesive roll 623, a third magnetic sheet unwinding roll 631, a third winding roll 632, a third adhesive roll 633, a fourth magnetic sheet unwinding roll 641, a fourth winding roll 642, a fourth adhesive roll 643, a fifth magnetic sheet unwinding roll 651, a fifth adhesive roll 653, a flattening roll 663, and a multilayer magnetic sheet winding roll 670, arranged from upstream to downstream in the manufacturing process. The manufacturing apparatus 600 may also be equipped with a number of guide rolls 680. Note that the guide rolls 680 can be placed in positions not described as necessary.

[0096] The manufacturing apparatus 600 may also manufacture a multilayer magnetic sheet 300 having two to four layers of magnetic strips 20. Alternatively, it may manufacture a multilayer magnetic sheet 300 having six or more layers of magnetic strips 20. In this case, the number of the first magnetic sheet unwinding rolls 611, etc., described above will be changed according to the number of magnetic strips 20.

[0097] There is no particular upper limit on the number of layers. The number of layers can be determined as appropriate. However, when winding the multilayer magnetic sheet 300, if there are too many layers, winding may become difficult or shape defects may occur during winding. For this reason, when winding the multilayer magnetic sheet 300, it is preferable to have 30 layers or less. More preferably, it is preferable to have 25 layers or less, more preferably 20 layers or less, more preferably 15 layers or less, and more preferably 10 layers or less.

[0098] As shown in Figure 8, a laminate is wound around the supply roll 601, in which a resin sheet 15 is laminated on the first surface 11A and the second surface 11B of the adhesive layer 10. As shown in Figure 9, the laminate unwound from the supply roll 601 has the resin sheet 15 positioned on the first surface 11A peeled off. As shown in Figure 13, the peeled resin sheet 15 is wound onto the resin sheet winding roll 602.

[0099] The laminate from which the resin sheet 15, positioned on the first surface 11A, has been peeled off is guided to the first adhesive roll 613 by the guide roll 680. The magnetic sheet 100, unwound from the first magnetic sheet unwinding roll 611, is further guided to the first adhesive roll 613.

[0100] The first adhesive roll 613 presses the magnetic sheet 100 against the laminate from which the resin sheet 15 has been peeled off, thereby bonding them. Specifically, the laminate and the magnetic sheet 100 are guided between two opposing rolls, and the two rolls are used to press the magnetic strip 20 of the magnetic sheet 100 against the first surface 11A of the adhesive layer 10, as shown in Figure 13, thereby bonding them.

[0101] The magnetic strip 20 to which the magnetic sheet 100 is bonded may be positioned so that its center coincides with the adhesive layer 10 in the width direction, or it may be positioned with its center separated from it. In this case, it is positioned so as to satisfy the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1).

[0102] The resin sheet 15 of the magnetic sheet 100, which has been bonded by the first bonding roll 613, is peeled off the magnetic sheet 100 and wound onto the first winding roll 612. The laminate, after the resin sheet 15 has been wound onto the first winding roll 612, is guided to the second bonding roll 623. The magnetic sheet 100, which has been unwound from the second magnetic sheet unwinding roll 621, is further guided onto the second bonding roll 623.

[0103] The second adhesive roll 623 presses and adheres the magnetic sheet 100 to the laminate guided from the first adhesive roll 613. The magnetic strip 20 to which the magnetic sheet 100 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate guided from the first adhesive roll 613 in the width direction, or it may be positioned with its center separated from the adhesive layer.

[0104] In this case, the arrangement satisfies the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1). The resin sheet 15 of the magnetic sheet 100, which has been bonded by the second bonding roll 623, is peeled off from the magnetic sheet 100 and wound onto the second winding roll 622.

[0105] After the resin sheet 15 is wound onto the second winding roll 622, the laminate is guided to the third bonding roll 633. The magnetic sheet 100, which has been unwound from the third magnetic sheet unwinding roll 631, is further guided to the third bonding roll 633.

[0106] The third adhesive roll 633 presses and adheres the magnetic sheet 100 to the laminate led from the second adhesive roll 623. The magnetic strip 20 to which the magnetic sheet 100 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate led from the second adhesive roll 623 in the width direction, or it may be positioned with its center separated from it.

[0107] In this case, the arrangement satisfies the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1). The resin sheet 15 of the magnetic sheet 100, which has been bonded by the third bonding roll 633, is peeled off from the magnetic sheet 100 and wound onto the third winding roll 632.

[0108] After the resin sheet 15 is wound onto the third winding roll 632, the laminate is guided to the fourth bonding roll 643. The magnetic sheet 100, which has been unwound from the fourth magnetic sheet unwinding roll 641, is further guided to the fourth bonding roll 643.

[0109] The fourth adhesive roll 643 presses and adheres the magnetic sheet 100 to the laminate led from the third adhesive roll 633. The magnetic strip 20 to which the magnetic sheet 100 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate led from the third adhesive roll 633 in the width direction, or it may be positioned with its center separated from it.

[0110] In this case, the arrangement satisfies the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1). The resin sheet 15 of the magnetic sheet 100, which has been bonded by the fourth bonding roll 643, is peeled off from the magnetic sheet 100 and wound onto the fourth winding roll 642.

[0111] After the resin sheet 15 is wound onto the fourth winding roll 642, the laminate is guided to the fifth bonding roll 653. The magnetic sheet 100, which has been unwound from the fifth magnetic sheet unwinding roll 651, is further guided to the fifth bonding roll 653.

[0112] The fifth adhesive roll 653 presses and adheres the magnetic sheet 100 to the laminate led from the fourth adhesive roll 643. The magnetic strip 20 to which the magnetic sheet 100 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate led from the fourth adhesive roll 643 in the width direction, or it may be positioned with its center separated from it.

[0113] In this case, the arrangement satisfies the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1). The laminate guided from the fifth bonding roll 653 to the flattening roll 663 is flattened by the flattening roll 663.

[0114] It is preferable that the magnetic strip 20 and the adhesive layer 10 are arranged such that the relationship between the magnetic strip 20 and the adhesive layer 10 satisfies the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1). However, positional misalignment may occur during the lamination process between the magnetic sheet 100 and the laminate. If this misalignment occurs, for example, gap a may become negative in the relationship between the magnetic strip 20 and the adhesive layer 10. In other words, on one side of the magnetic strip 20, the end of the magnetic strip 20 may protrude beyond the end of the adhesive layer 10. Even if the end of the magnetic strip 20 protrudes beyond the end of the adhesive layer 10 on one side of the magnetic strip 20, if the relationship between the magnetic strip 20 and the adhesive layer 10 on the other side of the magnetic strip 20 satisfies the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1), the magnetic strip 20 can maintain its adherence to the adhesive layer 10.

[0115] The laminated material after the planarization process becomes the multilayer magnetic sheet 300 shown in Figure 4. The multilayer magnetic sheet 300 is guided to the multilayer magnetic sheet winding roll 670 via the guide roll 680. The multilayer magnetic sheet 300 is wound onto the multilayer magnetic sheet winding roll 670.

[0116] In addition to winding the multilayer magnetic sheet 300 onto the multilayer magnetic sheet winding roll 670, the multilayer magnetic sheet 300 may also be cut to the required length.

[0117] Figure 14 is a schematic diagram illustrating the manufacturing method of the multilayer magnetic sheet 300T. The multilayer magnetic sheet 300T is manufactured using the manufacturing apparatus 700 shown in Figure 14. Figure 14 shows the manufacturing apparatus 700 for manufacturing the multilayer magnetic sheet 300T, which contains 25 layers of magnetic strips 20.

[0118] The manufacturing method for this multilayer magnetic sheet 300T involves stacking multiple multilayer magnetic sheets 300 to produce the multilayer magnetic sheet 300T. The number of stacks of magnetic strips 20 in the multilayer magnetic sheet 300T can be adjusted by changing the number of multilayer magnetic sheets 300 used and the number of stacks of magnetic strips 20 in the multilayer magnetic sheets 300 used.

[0119] The manufacturing apparatus 700 is mainly equipped with, from upstream to downstream of the manufacturing process, a supply roll 701, a resin sheet winding roll 702, a first multilayer magnetic sheet unwinding roll 711, two first winding rolls 712, a first adhesive roll 713, a second multilayer magnetic sheet unwinding roll 721, two second winding rolls 722, a second adhesive roll 723, a third multilayer magnetic sheet unwinding roll 731, two third winding rolls 732, a third adhesive roll 733, a fourth multilayer magnetic sheet unwinding roll 741, two fourth winding rolls 742, a fourth adhesive roll 743, a fifth multilayer magnetic sheet unwinding roll 751, a fifth winding roll 752, a fifth adhesive roll 753, a flattening roll 763, and a cutting section 770. The manufacturing apparatus 700 may also be equipped with a guide roll 780. The manufacturing apparatus 700 may be further equipped with multiple guide rolls 780. Note that the guide rolls 780 can be placed in positions not shown as needed. Also, the number of first multilayer magnetic sheet unwinding rolls 711, etc., is changed according to the number of magnetic strips 20. There is no particular upper limit on the number of layers.

[0120] The manufacturing apparatus 700 may produce a multilayer magnetic sheet 300T with 25 to 80 layers of magnetic strips 20. It may also produce a multilayer magnetic sheet 300T with more than 80 layers of magnetic strips 20, or a multilayer magnetic sheet 300T with fewer than 25 layers of magnetic strips 20. The number of magnetic strips 20 in the multilayer magnetic sheet 300T is preferably 10 or more, and more preferably 15 or more. Furthermore, the total number of laminated magnetic strips 20 is preferably 200 or less. In this case, the number of the first multilayer magnetic sheet unwinding rolls 711, etc., described above, is changed according to the number of magnetic strips 20. It is also changed by the number of layers of magnetic strips 20 in the multilayer magnetic sheet 300, such as the first multilayer magnetic sheet 300.

[0121] As shown in Figure 8, a laminate is wound around the supply roll 701, in which a resin sheet 15 is laminated on the first surface 11A and the second surface 11B of the adhesive layer 10. As shown in Figure 9, the laminate unwound from the supply roll 701 has the resin sheet 15 positioned on the first surface 11A peeled off. As shown in Figure 14, the peeled resin sheet 15 is wound onto the resin sheet winding roll 702.

[0122] The laminate from which the resin sheet 15, positioned on the first surface 11A, has been peeled off is guided by the guide roll 780 to the first bonding roll 713. The first bonding roll 713 is further guided by the multilayer magnetic sheet 300 unwound from the first multilayer magnetic sheet unwinding roll 711.

[0123] Alternatively, a multilayer magnetic sheet unwinding roll may be used as the supply roll 701. When a multilayer magnetic sheet unwinding roll is used as the supply roll 701, one of the two resin sheets 15 of the unwound multilayer magnetic sheet is peeled off and guided to the first bonding roll 713.

[0124] The multilayer magnetic sheet 300, guided to the first adhesive roll 713, has the resin sheet 15 facing the laminate guided from the supply roll 701 of the two resin sheets 15 peeled off. The peeled resin sheet 15 is then wound onto the first winding roll 712.

[0125] The first adhesive roll 713 presses and adheres the multilayer magnetic sheet 300, from which the resin sheet 15 has been peeled, to the laminate from which the resin sheet 15 has been peeled. Specifically, the laminate and the multilayer magnetic sheet 300 are guided between two opposing rolls, and the two rolls are used to press and adhere the magnetic strip 20 of the multilayer magnetic sheet 300 to the first surface 11A of the adhesive layer 10, as shown in Figure 14.

[0126] The magnetic strip 20 to which the multilayer magnetic sheet 300 is bonded may be positioned so that its center coincides with the adhesive layer 10 in the width direction, or it may be positioned with its center separated from it. In this case, it is positioned so as to satisfy the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1).

[0127] The remaining resin sheet 15 of the multilayer magnetic sheet 300, which has been bonded by the first bonding roll 713, is peeled off from the multilayer magnetic sheet 300 and wound onto the first winding roll 712. The laminate is then guided to the second bonding roll 723. The second bonding roll 723 is further guided to the multilayer magnetic sheet 300 that has been unwound from the second multilayer magnetic sheet unwinding roll 721.

[0128] As the multilayer magnetic sheet 300 is guided to the second adhesive roll 723, one of the two resin sheets 15, the resin sheet 15 facing the laminate guided from the first adhesive roll 713, is peeled off. The peeled resin sheet 15 is then wound onto the second winding roll 722.

[0129] The second adhesive roll 723 presses and adheres the multilayer magnetic sheet 300 to the laminate guided by the first adhesive roll 713. The magnetic strip 20 to which the multilayer magnetic sheet 300 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate guided by the first adhesive roll 713 in the width direction, or it may be positioned with its center separated from it. In this case, it is positioned so as to satisfy the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1).

[0130] The remaining resin sheet 15 of the multilayer magnetic sheet 300, which has been bonded by the second bonding roll 723, is peeled off from the multilayer magnetic sheet 300 and wound onto the second winding roll 722.

[0131] Subsequently, the laminate is guided to the third bonding roll 733. The third bonding roll 733 is further guided to the multilayer magnetic sheet 300 unwound from the third multilayer magnetic sheet unwinding roll 731.

[0132] As the multilayer magnetic sheet 300 is guided to the third adhesive roll 733, one of the two resin sheets 15, the resin sheet 15 facing the laminate guided from the second adhesive roll 723, is peeled off. The peeled resin sheet 15 is then wound onto the third winding roll 732.

[0133] The third adhesive roll 733 presses and adheres the multilayer magnetic sheet 300 to the laminate led from the second adhesive roll 723. The magnetic strip 20 to which the multilayer magnetic sheet 300 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate led from the second adhesive roll 723 in the width direction, or it may be positioned with its center separated from it. In this case, it is positioned so as to satisfy the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1).

[0134] The remaining resin sheet 15 of the multilayer magnetic sheet 300, which has been bonded by the third bonding roll 733, is peeled off from the multilayer magnetic sheet 300 and wound onto the third winding roll 732.

[0135] Subsequently, the laminate is guided to the fourth bonding roll 743. The fourth bonding roll 743 is further guided to the multilayer magnetic sheet 300 unwound from the fourth multilayer magnetic sheet unwinding roll 741.

[0136] As the multilayer magnetic sheet 300 is guided to the fourth adhesive roll 743, one of the two resin sheets 15, the resin sheet 15 facing the laminate guided from the third adhesive roll 733, is peeled off. The peeled resin sheet 15 is then wound onto the fourth winding roll 742.

[0137] The fourth adhesive roll 743 presses and adheres the multilayer magnetic sheet 300 to the laminate led from the third adhesive roll 733. The magnetic strip 20 to which the multilayer magnetic sheet 300 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate led from the third adhesive roll 733 in the width direction, or it may be positioned with its center separated from it. In this case, it is positioned so as to satisfy the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1).

[0138] The remaining resin sheet 15 of the multilayer magnetic sheet 300, which has been bonded by the fourth bonding roll 743, is peeled off from the multilayer magnetic sheet 300 and wound onto the fourth winding roll 742.

[0139] Subsequently, the laminate is guided to the fifth bonding roll 753. The fifth bonding roll 753 is further guided to the multilayer magnetic sheet 300 unwound from the fifth multilayer magnetic sheet unwinding roll 751.

[0140] As the multilayer magnetic sheet 300 is guided to the fifth adhesive roll 753, one of the two resin sheets 15, the resin sheet 15 facing the laminate guided from the fourth adhesive roll 743, is peeled off. The peeled resin sheet 15 is then wound onto the fifth winding roll 752.

[0141] The fifth adhesive roll 753 presses and adheres the multilayer magnetic sheet 300 to the laminate led from the fourth adhesive roll 743. The magnetic strip 20 to which the multilayer magnetic sheet 300 is adhered may be positioned so that its center coincides with the adhesive layer 10 of the laminate led from the fourth adhesive roll 743 in the width direction, or it may be positioned with its center separated from it. In this case, it is positioned so as to satisfy the relationships 0 mm < gap a and 0 mm < gap b (see Figure 1).

[0142] The laminate, guided from the fifth bonding roll 753 to the flattening roll 763, is flattened by the flattening roll 763. Furthermore, after the fifth bonding roll 753, a step may be provided in which an amorphous alloy strip, a nanocrystalline alloy strip, other magnetic material, a metal foil such as aluminum, a resin sheet, etc., is bonded as an outer layer. In this case, the remaining resin sheet 15 of the multilayer magnetic sheet 300 bonded by the fifth bonding roll 753 is peeled off from the multilayer magnetic sheet 300 and guided to the sixth bonding roll (not shown). An outer layer material selected from amorphous alloy strips, nanocrystalline alloy strips, other magnetic materials, a metal foil such as aluminum, a resin sheet, etc., may be guided to the sixth bonding roll and bonded.

[0143] The laminated material after the planarization process becomes the multilayer magnetic sheet 300T shown in Figure 6. The multilayer magnetic sheet 300T is cut to a desired length at the cutting section 770. The desired length can be, for example, 100 mm or more and 1000 mm or less. The length of the multilayer magnetic sheet 300T can be appropriately changed based on the specifications required for the multilayer magnetic sheet 300T. The multilayer magnetic sheet 300T may also be wound up if it has a windable number of layers. After that, it may be cut to the desired length and used.

[0144] Here, a multilayer magnetic sheet 300T with 25 layers of magnetic strips 20 was manufactured by laminating a multilayer magnetic sheet 300 with 5 layers of magnetic strips 20 five times. However, a multilayer magnetic sheet 300T with 50 layers of magnetic strips 20 may also be manufactured by further laminating the multilayer magnetic sheet 300T with 25 layers of magnetic strips 20.

[0145] By setting the number of magnetic strips 20 in the multilayer magnetic sheet 300T to, for example, 25 to approximately 80 layers, the multilayer magnetic sheet 300T can be used for contactless charging of mobile devices such as automobiles. The number of layers may be 80 or more, or 25 or fewer.

[0146] Furthermore, the number of layers of magnetic strips 20 in the laminated multilayer magnetic sheet 300 may be changed based on the number of magnetic strip layers 20 in the final multilayer magnetic sheet 300T.

[0147] Furthermore, the number of magnetic strip layers 20 in each of the multiple multilayer magnetic sheets 300 to be stacked may differ. In other words, a multilayer magnetic sheet 300T may be manufactured by a combination of multiple multilayer magnetic sheets 300 with different numbers of magnetic strip layers 20.

[0148] By manufacturing the multilayer magnetic sheet 300T using the manufacturing equipment 700, it is easier to miniaturize the equipment compared to manufacturing it using the manufacturing equipment 600. When manufacturing using the manufacturing equipment 600, it is necessary to arrange the first magnetic sheet unwinding roll 611, on which the magnetic sheet 100 is wound, for the number of layers of the magnetic strip 20, which tends to make the manufacturing equipment 600 larger.

[0149] In contrast, the manufacturing apparatus 700 uses a first multilayer magnetic sheet unwinding roll 711 around which the multilayer magnetic sheet 300 is wound, making it easier to miniaturize the manufacturing apparatus. In other words, it is easier to manufacture the multilayer magnetic sheet 300T.

[0150] With the magnetic sheet 100, rolled magnetic sheet 200, multilayer magnetic sheet 300, and multilayer magnetic sheet 300T configured as described above, the width A of the area where the adhesive 12 is provided in the adhesive layer 10 is wider than the width B of the magnetic strip 20. When attaching the magnetic strip 20 to the adhesive layer 10, even if meandering occurs in the adhesive layer 10 or the magnetic strip 20, the adhesive 12 of the adhesive layer 10 is more likely to be distributed over the entire surface of the magnetic strip 20.

[0151] By setting the value obtained by subtracting width B from width A to 0.2 mm or more, it is easier to prevent the occurrence of areas on the magnetic strip 20 where the adhesive 12 is not present when attaching the magnetic strip 20 to the adhesive layer 10. By setting the value obtained by subtracting width B from width A to 3 mm or less, it is easier to prevent the area on the magnetic sheet 100 where the magnetic strip 20 is not present from becoming large. In addition, when the magnetic sheets 100 are arranged in parallel, it is easier to prevent the gap between magnetic strips (magnetic gap) from becoming large.

[0152] By satisfying the relationships 0mm < gap a and 0mm < gap b, when the magnetic strip 20 is attached to the adhesive layer 10, the magnetic strip 20 is prevented from protruding from the area where the adhesive 12 is provided. Therefore, it is easier to prevent the occurrence of areas on the magnetic strip 20 where the adhesive 12 is not present.

[0153] By making the magnetic thin strip 20 an amorphous alloy thin strip or a nanocrystalline alloy thin strip, it is possible to make the magnetic thin strip 20 a soft magnetic thin strip. Furthermore, the magnetic thin strip 20 can be formed using an alloy.

[0154] By manufacturing the magnetic strip 20 using a single-roll method, it becomes easier to create the magnetic strip 20 in a long shape.

[0155] By incorporating multiple small pieces 22 into the magnetic strip 20, it becomes easier to improve the properties of the magnetic sheet 100, the wound magnetic sheet 200, the multilayer magnetic sheet 300, and the multilayer magnetic sheet 300T. Specifically, when the magnetic sheet 100, the wound magnetic sheet 200, the multilayer magnetic sheet 300, and the multilayer magnetic sheet 300T are used as magnetic materials for inductors, it becomes easier to improve the Q value. Furthermore, when the magnetic sheet 100, the wound magnetic sheet 200, the multilayer magnetic sheet 300, and the multilayer magnetic sheet 300T are used as magnetic materials for magnetic shielding, it becomes easier to reduce eddy current losses by interrupting the current path in the magnetic strip 20.

[0156] By winding the magnetic sheet 100 into a ring or spiral shape, the resulting rolled magnetic sheet 200 becomes easier to transport after manufacturing.

[0157] By providing a resin sheet 15 at the first laminated end 301 or the second laminated end 302, it becomes easier to protect the manufactured multilayer magnetic sheets 300 and 300T. For example, it becomes easier to prevent damage to the adhesive layer 10 and magnetic strip 20 when transporting the manufactured multilayer magnetic sheets 300 and 300T. Furthermore, an amorphous alloy strip, a nanocrystalline alloy strip, or other magnetic material, such as a metal foil made of aluminum, or a resin sheet may be attached to the first laminated end 301.

[0158] By laminating two or more adhesive layers 10 between at least one of the ten or more stacked magnetic thin strips 20, it becomes easier to manufacture a multilayer magnetic sheet 300T having ten or more magnetic thin strips 20.

[0159] The scope of this disclosure is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of this disclosure. For example, the magnetic sheet 100, the rolled magnetic sheet 200, the multilayer magnetic sheet 300, and the multilayer magnetic sheet 300T according to this disclosure can be used as inductive elements and the like. [Explanation of Symbols]

[0160] 10…Adhesive layer, 10X…End of first adhesive layer, 10Y…End of second adhesive layer, 11…Support, 11A…First surface, 11B…Second surface, 12…Adhesive, 20…Magnetic strip, 20X…End of first strip, 20Y…End of second strip, 22…Small piece, 15…Resin sheet, 100…Magnetic sheet, 200…Rolled magnetic sheet, 300…Multilayer magnetic sheet, 300T…Multilayer magnetic sheet, 301…End of first layer, 302…End of second layer, A,B…Width, a,b…Gap

Claims

1. A support formed in a strip shape, and a plurality of adhesive layers having adhesives provided on the first and second surfaces of the support, A plurality of magnetic strips formed in a strip shape using a magnetic material, each of which is placed between adjacent adhesive layers and adhered to the adhesive of the adhesive layer, A multilayer magnetic sheet provided with Each of the aforementioned multiple magnetic thin strips contains multiple small pieces, at least one of which is arranged at a different position in the width direction and stacked. The dimensions of the adhesive layer, wherein the dimension in the direction perpendicular to the longitudinal direction of the adhesive layer is width A, A multilayer magnetic sheet that satisfies the relationship 0.2 mm ≤ (width A - width B) ≤ 3 mm, where the dimensions of the magnetic thin strip are such that the width B is the dimension in the direction perpendicular to the longitudinal direction of the magnetic thin strip.

2. The multilayer magnetic sheet according to claim 1, wherein the magnetic strip is an amorphous alloy strip or a nanocrystalline alloy strip.

3. The magnetic tape is a component manufactured by a single-roll method in which molten metal is discharged onto a rotating cooling roll and rapidly cooled and solidified. The multilayer magnetic sheet according to claim 1 or 2, wherein the magnetic strip has an elongated shape with its longitudinal direction aligned with the rotation direction of the cooling roll, and the dimension of the magnetic strip in the direction perpendicular to the longitudinal direction is the width B.

4. In the lamination direction in which the magnetic strip and the adhesive layer are laminated, a resin sheet, which is a film-like member formed using resin, is provided at the first lamination end or the second lamination end opposite to the first lamination end. The multilayer magnetic sheet according to any one of claims 1 to 3, wherein the resin sheet is bonded to the adhesive of the adhesive layer.

5. Ten or more of the magnetic thin strips are laminated with the adhesive layer in between, A multilayer magnetic sheet according to any one of claims 1 to 4, wherein two or more adhesive layers are laminated between at least one of a plurality of adjacent magnetic strips where the adhesive layers are arranged.

Images