Shield material

Abstract

Provided is a shield material which exhibits a sufficient shielding effect for a frequency range of 1-100 MHz (in particular, a frequency range on the lower side, from 1-10 MHz) and preferably exhibits a sufficient shielding effect even at a relatively thin total thickness of about 10-30 μm.　The shield material is formed by laminating a conductive layer, which has a total thickness Tc and is made of a copper plating film, in the thickness direction of a magnetic layer, which has a total thickness Tm and is made of an iron-nickel soft magnetic material containing 70-85 mass% of nickel. When a KEC method is used to measure the shield effect using a magnetic field shield evaluation device, the shield effect SE10M for a frequency of 10 MHz is 50 dB or more, and the shield effect SE1M / (Tm + Tc) for a frequency of 1 MHz is 1.4 dB / μm or more.

Description

Shielding material

[0001] The present invention relates to a shielding material.

[0002] Conventionally, highly sensitive semiconductor-applied devices and equipment, such as converters, sensors, detectors, measuring instruments, and personal digital assistants (PDAs), that convert alternating current (AC) to direct current (DC), as well as flexible printed circuit boards (FPCs) that constitute the electrical circuits of the above-mentioned devices and equipment, have been used in a variety of fields, including communications, office automation and home appliances, air conditioning, lighting, uninterruptible power supplies, motors, and inverters. Due to the recent trend toward lighter weight, the housings of the above-mentioned devices and equipment are being transitioned from metal to resin. When using a resin housing, shielding (especially magnetic shielding) is required to suppress malfunctions caused by noise. Furthermore, noise shielding may also be required for the above-mentioned FPCs. Shielding materials used in the above-mentioned devices and equipment or FPCs are made of magnetic materials such as soft magnetic iron, silicon steel, copper, permalloy, amorphous, and nanocrystalline materials. For example, Japanese Patent Application Laid-Open No. 2021-136399 discloses a shielding material that exhibits shielding effects against noise in the frequency range from 1 MHz to 100 MHz.

[0003] The shielding material disclosed in JP 2021-136399 A is composed of a magnetic layer made of an iron (Fe)-based nanocrystalline alloy and a conductive layer made of a nickel (Ni)-plated film stacked in the thickness direction. The shielding material described as an example in JP 2021-136399 A 1 is composed of, for example, a 20 μm-thick magnetic layer made of an Fe-based nanocrystalline alloy and a 0.5 μm-thick conductive layer made of an electrolytic Ni-plated film stacked in the thickness direction. The shielding material in this example is described as having a shielding effectiveness measured by the well-known KEC method of approximately 38 dB at 1 MHz, approximately 33 dB at 10 MHz, and approximately 23 dB at 100 MHz.

[0004] Japanese Patent Application Laid-Open No. 2021-136399

[0005] The shielding material disclosed in JP 2021-136399 A exhibits the above-mentioned shielding effect with a relatively thin total thickness of about 20 μm, and is therefore thought to meet the expectations of customers seeking lightweight, compact, flexible, and free-design devices and equipment. However, when focusing on the gradient of the shielding effect, the gradient is a negative value of approximately -0.67 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, and a negative value of approximately -0.10 dB / MHz in the higher frequency range of 10 MHz to 100 MHz. Therefore, the shielding material disclosed in JP 2021-136399 A exhibits a characteristic in which the shielding effect attenuates as the noise frequency increases, and therefore does not meet the demands of customers who expect good shielding effects in the frequency range of 1 MHz to 100 MHz (especially the lower frequency range of 1 MHz to 10 MHz).

[0006] An object of the present invention is to provide a shielding material that exhibits sufficient shielding effect in the frequency range of 1 MHz to 100 MHz (especially the lower frequency range of 1 MHz to 10 MHz), and preferably exhibits sufficient shielding effect even with a relatively thin total thickness of approximately 10 μm to 30 μm.

[0007] The inventor thoroughly examined the configuration of the shielding material disclosed in JP 2021-136399 A, which combines a magnetic layer and a conductive layer, and focused on permalloy foil, which is known for its high magnetic permeability, and copper foil, which is known for its high conductivity. Through further ingenuity, the inventor discovered an appropriate combination of a magnetic layer and a conductive layer, and came up with the invention.

[0008] The shielding material according to the present invention is formed by laminating a conductive layer having a total thickness Tc made of a copper plating film in the thickness direction of a magnetic layer having a total thickness Tm made of an iron-nickel soft magnetic material containing 70% by mass or more and 85% by mass or less of nickel, and in the shielding effect measured using a magnetic field shield evaluation device according to the KEC method, the shielding effect SE at a frequency of 10 MHz is １０Ｍ is 50 dB or more, and the shielding effect SE at a frequency of 1 MHz １Ｍ / (Tm+Tc) is 1.4 dB / μm or more.

[0009] In the shielding material according to the present invention, the magnetic layer preferably satisfies 10 μm≦Tm≦30 μm, and the conductive layer preferably satisfies 0.05≦Tc / Tm≦0.2.

[0010] The shielding material according to the present invention preferably has a shielding effect SE at a frequency of 1 MHz when measured using a magnetic field shield evaluation device according to the KEC method. １Ｍ is 25 dB or more.

[0011] The shielding material according to the present invention preferably has a shielding effect SE at a frequency of 100 MHz when measured using a magnetic field shield evaluation device according to the KEC method. １００Ｍ is 70 dB or more.

[0012] The shielding material according to the present invention preferably has a shielding effect SE at a frequency of 10 MHz when measured using a magnetic field shield evaluation device according to the KEC method. １０Ｍ / (Tm+Tc) is 2.7 dB / μm or more.

[0013] According to the present invention, it is possible to provide a shielding material that exhibits sufficient shielding effect in the frequency range of 1 MHz to 100 MHz (especially the lower frequency range of 1 MHz to 10 MHz), and further, by appropriately designing its configuration, exhibits sufficient shielding effect even with a relatively thin total thickness of approximately 10 μm to 30 μm.

[0014] 1 is a diagram showing an example of a shielding material according to the present invention, in which a conductive layer is provided on both sides of a magnetic layer in the thickness direction; 2 is a diagram showing an example of a shielding material according to the present invention, in which a conductive layer is provided on both sides of a magnetic layer in the thickness direction and also on both sides of a magnetic layer in the width direction; and 3 is a diagram showing an example of a shielding material according to the present invention, in which a conductive layer is provided on one side of a magnetic layer in the thickness direction.

[0015] The following describes an embodiment of the shielding material according to the present invention, citing a configuration example that the inventor considers to be preferable, with reference to the drawings as appropriate. Note that the shielding material according to the present invention is not limited to the contents of the embodiment exemplified here, but is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims. In addition, in this invention, the frequency range from 1 MHz to 10 MHz is defined as the low frequency range, and the frequency range from 10 MHz to 100 MHz is defined as the high frequency range.

[0016] Shielding materials according to the present invention can have, as embodiments thereof, configurations such as shielding material 1A, shielding material 1B, and shielding material 1C shown in Figures 1, 2, and 3. Shielding materials 1A, 1B, and 1C are each composed of a magnetic layer 11 and a conductive layer 12. In all of shielding materials 1A, 1B, and 1C, magnetic layer 11 is made of an iron-nickel soft magnetic material containing 70% by mass or more and 85% by mass or less of nickel, and conductive layer 12 is made of a copper plating film.

[0017] 1 has a three-layer clad structure in which conductive layers 12 (12a, 12b) are laminated on both sides (Z1 side and Z2 side) in the Z direction (thickness direction) of a magnetic layer 11. The shielding material 1A can be manufactured, for example, by a manufacturing method in which the conductive layers 12 (12a, 12b) are formed while both end portions in the X direction of the magnetic layer 11 (end portions on the X1 side and X2 side) are masked, or by a manufacturing method in which the conductive layers 12 (12a, 12b, 12c shown in FIG. 2) are formed over the entire magnetic layer 11 and then both end portions in the X direction are cut off by slitting or the like.

[0018] As shown in Figure 1, the shielding material 1A has a thickness of t. The magnetic layer 11 has a thickness of t1. The conductive layer 12a has a thickness of t2a. The conductive layer 12b has a thickness of t2b. Therefore, t = t1 + t2 = t1 + t2a + t2b. If the total thickness of the magnetic layers 11 is Tm and the total thickness of the conductive layers 12 is Tc, then Tm = t1 and Tc = 2 x t2 = 2 x (t2a + t2b).

[0019] 2 has a three-layer clad structure in which conductive layers 12 (12a, 12b) are laminated on both sides (Z1 side and Z2 side) of the magnetic layer 11 in the Z direction (thickness direction), similar to the shielding material 1A. The shielding material 1B differs from the configuration of the shielding material 1A in that it has conductive layers 12 (12c) on both sides (X1 side and X2 side) in the width direction (X direction). The shielding material 1B can be manufactured, for example, by a manufacturing method in which the conductive layers 12 (12a, 12b, 12c) are formed over the entire magnetic layer 11.

[0020] As shown in FIG. 2, the shielding material 1B has a thickness of t. The magnetic layer 11 has a thickness of t1. The conductive layer 12a has a thickness of t2a. The conductive layer 12b has a thickness of t2b. The conductive layer 12c has a thickness of t2c on both the X1 side and the X2 side. Therefore, t = t1 + t2 = t1 + t2a + t2b. When the total thickness of the magnetic layers 11 is Tm and the total thickness of the conductive layers 12 is Tc, then Tm = t1 and Tc = 2 × t2 = 2 × (t2a + t2b).

[0021] 3 differs from the shielding materials 1A and 1B in that it has a two-layer clad structure in which a conductive layer 12 (12a) is laminated on one side (Z1 side) in the Z direction (thickness direction) of the magnetic layer 11. The shielding material 1C can be manufactured, for example, by a manufacturing method in which the conductive layer 12 (12a) is formed while masking one side (Z2 side) in the Z direction and both end portions in the X direction (end portions on the X1 side and X2 side) of the magnetic layer 11, a manufacturing method in which the conductive layer 12 (12a, 12c shown in FIG. 2) is formed while masking the Z2 side of the magnetic layer 11, and then both end portions in the X direction are cut off by slitting or the like, or a manufacturing method in which the conductive layer 12 (12a, 12b shown in FIG. 1, 12c shown in FIG. 2) is formed over the entire magnetic layer 11, and then the conductive layer 12 on the Z2 side (12b shown in FIG. 1) is removed by polishing, grinding, or the like, and then both end portions in the X direction are cut off by slitting or the like.

[0022] As shown in Figure 3, the shielding material 1C has a thickness of t. The magnetic layer 11 has a thickness of t1. The conductive layer 12 (12a) has a thickness of t2 (t2a). Therefore, t = t1 + t2 = t1 + t2a. If the total thickness of the magnetic layer 11 is Tm and the total thickness of the conductive layer 12 is Tc, then Tm = t1 and Tc = t2 = t2a.

[0023] The shielding material 1A shown in FIG. 1 will be described below as a representative example.

[0024] The magnetic layer 11 of the shielding material 1A is made of a magnetic metal plate. The magnetic metal plate that makes up the magnetic layer 11 is an iron-nickel soft magnetic material containing 70% by mass or more and 85% by mass or less of nickel. Therefore, when manufacturing the shielding material 1A, a metal plate made of an iron-nickel soft magnetic material containing 70% by mass or more and 85% by mass or less of nickel is prepared as the magnetic metal plate that makes up the magnetic layer 11. The iron-nickel soft magnetic material containing 70% by mass or more and 85% by mass or less of nickel may be, for example, PC or E11 (collectively referred to as "PC permalloy") specified in JIS-C2531:1999 (Iron-nickel soft magnetic materials).

[0025] In this invention, PC Permalloy may be, for example, an alloy containing 75% by mass or more and 80% by mass or less of Ni, with the balance being Fe and unavoidable impurities (80% Ni-Fe alloy), an alloy containing 75% by mass or more and 80% by mass or less of Ni, with the balance being Fe and unavoidable impurities (80% Ni-5% Mo-Fe alloy), or an alloy containing 75% by mass or more and 80% by mass or less of Ni and 3% by mass or more and 5% by mass or less of Mo (molybdenum), with the balance being Fe and unavoidable impurities (78% Ni-5% Mo-4% Cu-Fe alloy). PC Permalloy can usually be processed and formed by laser cutting, welding, bending, drawing, etc.

[0026] PC Permalloy has a sufficiently high magnetic permeability and saturation magnetic flux density in the low-frequency range where magnetic fields become a problem. Generally, noise (especially magnetic) easily passes through materials with high magnetic permeability, so PC Permalloy increases the absorption loss due to refraction and detouring of noise (especially magnetic). From this perspective, the shielding material 1A having the magnetic layer 11 made of PC Permalloy as described above is expected to have a sufficient noise shielding effect (especially magnetic shielding effect) mainly in the low-frequency range (1 MHz to 10 MHz). Therefore, the magnetic layer 11 constituting the shielding material 1A uses an iron-nickel soft magnetic material (such as the above-described PC Permalloy) containing 70% by mass or more and 85% by mass or less of nickel.

[0027] The magnetic layer 11 of the shielding material 1A has a predetermined thickness t1. The predetermined thickness t1 of the magnetic layer 11 preferably satisfies the relationship 10 μm≦Tm≦30 μm, where Tm is the total thickness of the magnetic layer 11. A magnetic layer with a Tm exceeding 30 μm can be expected to improve shielding effectiveness in the lower frequency range of 1 MHz to 10 MHz, but may not be suitable for applications requiring lightweight, compact, flexible, or flexible design. From this perspective, the magnetic layer 11 of the shielding material 1A is preferably configured so that Tm is 30 μm or less. A magnetic layer with a Tm of less than 10 μm may have insufficient shielding effectiveness in the lower frequency range of 1 MHz to 10 MHz. From this perspective, the magnetic layer 11 of the shielding material 1A is preferably configured so that Tm is 10 μm or more.

[0028] The conductive layer 12 (12a, 12b) of the shielding material 1A is composed of a plating film formed by plating the magnetic layer 11 (magnetic metal plate material). The plating is copper plating, and the plating film is a copper plating film. Therefore, copper plating is performed when manufacturing the shielding material 1A. A conventional copper sulfate plating solution can be used in the copper plating. Furthermore, in the copper plating, the copper plating conditions (solution temperature, current density, current application time, etc.) are selected so that the copper plating film is formed to a predetermined thickness t2. The copper plating film formed by the copper plating is composed of high-purity copper (Cu) and unavoidable impurities. High-purity copper has a high conductivity of approximately 100% IACS. Therefore, a copper plating film composed of high-purity copper and unavoidable impurities is likely to exhibit high conductivity similar to that of copper. Known metal materials with high electrical conductivity include, in addition to copper, silver (Ag) with an IACS of approximately 106%, gold (Au) with an IACS of approximately 72%, and aluminum (Al) with an IACS of approximately 62%. Copper is a practical metal material and is therefore preferred because it has higher electrical conductivity than gold or aluminum and is less expensive than gold or silver.

[0029] Generally, the higher the conductivity of a metal material, the higher the noise (especially magnetic) reflection loss. Copper exhibits high noise (especially magnetic) reflection loss in the frequency range of approximately 3 MHz or higher. Therefore, a copper plating film made of high-purity copper and unavoidable impurities is likely to exhibit the same noise (especially magnetic) reflection loss as copper. From this perspective, a shielding material 1A having conductive layers 12 (12a, 12b) made of copper plating film is expected to provide sufficient noise shielding effect (especially magnetic shielding effect) mainly in the higher frequency range (10 MHz to 100 MHz). Therefore, a copper plating film made of high-purity copper is used for the conductive layers 12 (12a, 12b) constituting the shielding material 1A.

[0030] Furthermore, the conductive layers 12 (12a, 12b) of the shielding material 1A have a predetermined thickness t2 (t2a, t2b). The predetermined thickness t2 (t2a, t2b) of the conductive layers 12 (12a, 12b) preferably satisfies 0.05≦Tc / Tm≦0.2, where Tm is the total thickness of the magnetic layers 11 and Tc is the total thickness of the conductive layers 12. If the copper plating film becomes excessively thick, resulting in a conductive layer with a Tc / Tm ratio exceeding 0.2, while improved shielding effectiveness in the higher frequency ranges may be expected, this may not be suitable for applications requiring lightweight, compact, flexible, or flexible design. From this perspective, the conductive layers 12 (12a, 12b) of the shielding material 1A are preferably configured so that Tc / Tm is 0.2 or less. Furthermore, if the copper plating film becomes too thin and the conductive layer has a Tc / Tm of less than 0.05, the total amount of copper may become insufficient, resulting in insufficient shielding effect in the higher frequency range. From this perspective, the conductive layers 12 (12a, 12b) of the shielding material 1A are preferably configured so that the Tc / Tm is 0.05 or greater.

[0031] As described above, the shielding material 1A is formed by laminating conductive layers 12 (12a, 12b) made of copper plating films in the thickness direction of a magnetic layer 11 made of an iron-nickel soft magnetic material (PC permalloy) containing 70% to 85% by mass of nickel. Furthermore, in the shielding material 1A, when the total thickness of the magnetic layers 11 is Tm and the total thickness of the conductive layers 12 is Tc, preferably, the magnetic layers 11 satisfy 10 μm≦Tm≦30 μm, and the conductive layers 12 satisfy 0.05≦Tc / Tm≦0.2. The shielding material 1A is heat-treated as necessary.

[0032] The shielding material 1A, which is an example of an embodiment of the shielding material according to the present invention, has a shielding effect SE at a frequency of 10 MHz measured using a magnetic field shield evaluation device according to the KEC method. １０Ｍ is 50 dB or more, and the shielding effect SE at a frequency of 1 MHz １Ｍ / (Tm+Tc) is 1.4 dB / μm or more.

[0033] The shielding material 1A has a magnetic layer 11 made of PC permalloy, which allows the characteristics of PC permalloy, which has a large noise absorption loss, to function properly, thereby improving the shielding effect in a relatively low frequency range. Furthermore, the shielding material 1A has a conductive layer 12 made of a copper plating film, which allows the characteristics of copper (copper plating film), which has a large noise reflection loss, to function properly, thereby improving the shielding effect in a relatively high frequency range. With this configuration, the shielding material 1A has the above-mentioned shielding effect SE at a frequency of 10 MHz. １０Ｍ Shielding effect SE of 50 dB or more and 1 MHz frequency １Ｍ This provides a special effect that the difference between Tm and Tc is 1.4 dB / μm or more, and a sufficient shielding effect can be exhibited in the frequency range from 1 MHz to 100 MHz (particularly in the lower frequency range from 1 MHz to 10 MHz).

[0034] Furthermore, the shielding material 1A, which is one example of an embodiment of the shielding material according to the present invention, can exhibit sufficient shielding effect even with a relatively thin total thickness of approximately 10 μm to 30 μm by appropriately designing its configuration so that the magnetic layer 11 satisfies 10 μm≦Tm≦30 μm and the conductive layer 12 (12a, 12b) satisfies 0.05≦Tc / Tm≦0.2.

[0035] In addition, the shielding material 1A preferably has a shielding effect SE of 1 MHz or less when measured using a magnetic field shield evaluation device according to the KEC method. １Ｍ shows 25 dB or more, or the shielding effect SE at a frequency of 100 MHz １００Ｍ shows 70 dB or more, or the shielding effect SE at a frequency of 10 MHz １０Ｍ / (Tm+Tc) is 2.7 dB / μm or more.

[0036] The shielding material 1A having the above-described configuration has been confirmed to be practicable, and a method for measuring the shielding effect using the magnetic shield evaluation device according to the KEC method will be described later.

[0037] Next, a shielding material corresponding to the configuration of the shielding material 1A having the above-described three-layer clad structure was actually produced, and its shielding effect was evaluated. Specimens 1 to 4 (shielding materials) shown in Table 1 are examples of the present invention. Specimens 5 and 6 (shielding materials) shown in Table 1 are shielding materials having a two-layer clad structure described in JP 2021-136399 A, listed for comparison with the examples of the present invention. Specimen 5 is a two-layer shielding material (see FIG. 2A for its shielding effect) consisting of a 20 μm thick magnetic layer made of an Fe-based nanocrystalline alloy and a 0.5 μm thick conductive layer made of a Ni-plated film. Specimen 6 is a two-layer shielding material (see FIG. 2A for its shielding effect) consisting of a 20 μm thick magnetic layer made of an Fe-based amorphous alloy and a 0.5 μm thick conductive layer made of a Ni-plated film.

[0038]

[0039] In specimen 1 (an example of the present invention), the magnetic layers constituting the shielding material have a layer thickness of 10 μm and a single layer, resulting in a total thickness Tm of 10 μm, which satisfies 10 μm≦Tm≦30 μm. Furthermore, the conductive layers constituting the shielding material have a layer thickness of 1 μm and a double layer, resulting in a total thickness Tc of 2 μm. Therefore, for specimen 1, Tc / Tm is 0.20, meaning that the conductive layers satisfy 0.05≦Tc / Tm≦0.2.

[0040] In specimen 2 (an example of the present invention), the magnetic layer constituting the shielding material has a layer thickness of 19 μm and consists of one layer, resulting in a total thickness Tm of 19 μm, which satisfies 10 μm≦Tm≦30 μm. Furthermore, the conductive layer constituting the shielding material has a layer thickness of 1 μm and consists of two layers, resulting in a total thickness Tc of 2 μm. Therefore, for specimen 2, Tc / Tm is 0.11, which means that the conductive layer satisfies 0.05≦Tc / Tm≦0.2.

[0041] In specimen 3 (an example of the present invention), the magnetic layer constituting the shielding material has a layer thickness of 20 μm and consists of one layer, resulting in a total thickness Tm of 20 μm, which satisfies 10 μm≦Tm≦30 μm. Furthermore, the conductive layer constituting the shielding material has a layer thickness of 1 μm and consists of two layers, resulting in a total thickness Tc of 2 μm. Therefore, for specimen 3, Tc / Tm is 0.10, which means that the conductive layer satisfies 0.05≦Tc / Tm≦0.2.

[0042] In specimen 4 (an example of the present invention), the magnetic layer constituting the shielding material has a layer thickness of 30 μm and consists of one layer, resulting in a total thickness Tm of 30 μm, which satisfies 10 μm≦Tm≦30 μm. Furthermore, the conductive layer constituting the shielding material has a layer thickness of 1 μm and consists of two layers, resulting in a total thickness Tc of 2 μm. Therefore, for specimen 4, Tc / Tm is 0.07, which means that the conductive layer satisfies 0.05≦Tc / Tm≦0.2.

[0043] In specimen 5 (comparative example), the magnetic layer constituting the shielding material has a layer thickness of 20 μm and the number of layers is one, so the total thickness Tm is 20 μm, which satisfies 10 μm≦Tm≦30 μm. In addition, the conductive layer constituting the shielding material has a layer thickness of 0.5 μm and the number of layers is one, so the total thickness Tc is 0.5 μm. As a result, Tc / Tm of specimen 5 is 0.03, so the conductive layer does not satisfy 0.05≦Tc / Tm≦0.2.

[0044] In specimen 6 (comparative example), the magnetic layer constituting the shielding material has a layer thickness of 20 μm and the number of layers is one, so the total thickness Tm is 20 μm, which satisfies 10 μm≦Tm≦30 μm. In addition, the conductive layer constituting the shielding material has a layer thickness of 0.5 μm and the number of layers is one, so the total thickness Tc is 0.5 μm. As a result, Tc / Tm of specimen 6 is 0.03, so the conductive layer does not satisfy 0.05≦Tc / Tm≦0.2.

[0045] Furthermore, specimens 7 to 13 (foil materials) shown in Table 2 are listed for comparison with the examples of the present invention, and are foil materials made of copper (Cu) (Cu foil) and foil materials made of PC permalloy (PC permalloy foil), which are conventionally used as shielding materials.

[0046]

[0047] The shielding effectiveness of specimens 1 to 6 shown in Table 1 and specimens 7 to 13 shown in Table 2 was measured using a magnetic field shield evaluation device based on the KEC method. The KEC method is a common name for a method of measuring the electromagnetic wave (electric field and magnetic field) shielding factor developed by the Kansai Electronics Manufacturing Center, and is known as a representative measurement method for evaluating the shielding effectiveness (electric field and magnetic field) of shielding materials targeting near-fields. For example, the shielding effectiveness SE at a frequency of 10 MHz was １０Ｍ is the received voltage V when the test sample (test piece) is present in a specified measurement environment (temperature 22°C, relative humidity 40% RH) at a measurement frequency of 10 MHz. １ and the received voltage V when the sample under test (test object) is not present. ０ and 20 log(V ０ / V １ ) is the value (dB) obtained by

[0048] Table 3 shows the shielding effectiveness SE of specimens 1 to 13 measured by the KEC method described above. Note that ">113.28" shown in Table 3 indicates that the measurement limit has been reached.

[0049]

[0050] Table 4 also shows the efficiency of the shielding effect (dB / μm) calculated using the values ​​shown in Tables 1, 2, and 3. The efficiency of the shielding effect is the ratio of the shielding effect SE shown in Table 3 to the total thickness (Tm+Tc) of the shielding material shown in Table 1, and is a value calculated by SE / (Tm+Tc). Similarly, the efficiency of the shielding effect is the ratio of the shielding effect SE shown in Table 3 to the foil thickness Tf (total thickness) of the foil material shown in Table 2, and is a value calculated by SE / Tf. Note that a "-" in Table 4 indicates that the shielding effect had reached the measurement limit.

[0051]

[0052] Table 5 also shows the gradient (dB / MHz) of the shielding effectiveness in the frequency ranges of 1 MHz to 10 MHz, 10 MHz to 100 MHz, and 1 MHz to 100 MHz, calculated using the values ​​of the shielding effectiveness shown in Table 3. The gradient of the shielding effectiveness is the difference between the shielding effectiveness SE of frequency A in the range from frequency A to frequency B (A<B). Ａ and the shielding effect SE at frequency B Ｂ Using the above, (SE Ｂ -SE Ａ ) / (B-A). In Table 5, "-" indicates that the shielding effect at 100 MHz reached the measurement limit.

[0053]

[0054] As shown in Table 3, the shielding material of specimen 1 (example of the present invention) had a shielding effect SE at a frequency of 1 MHz. １Ｍ is 25.76 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 61.53 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ The shielding effectiveness was 92.82 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 2.15 dB / μm at a frequency of 1 MHz, 5.13 dB / μm at a frequency of 10 MHz, and 7.74 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 3.97 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a positive value of 0.35 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a positive value of 0.68 dB / MHz over the entire frequency range of 1 MHz to 100 MHz.

[0055] As shown in Table 3, the shielding material of specimen 2 (example of the present invention) had a shielding effect SE of 1 MHz. １Ｍ is 37.70 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 83.83 dB, and the shielding effect SE at a frequency of 100 MHz １００ＭThe shielding effectiveness was 109.71 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 1.80 dB / μm at a frequency of 1 MHz, 3.99 dB / μm at a frequency of 10 MHz, and 5.22 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 5.13 dB / MHz in the lower frequency range from 1 MHz to 10 MHz, a positive value of 0.29 dB / MHz in the higher frequency range from 10 MHz to 100 MHz, and a positive value of 0.73 dB / MHz over the entire frequency range from 1 MHz to 100 MHz.

[0056] As shown in Table 3, the shielding material of specimen 3 (example of the present invention) had a shielding effect SE of 1 MHz. １Ｍ is 38.45 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 83.15 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ reached the measurement limit. As shown in Table 4, the efficiency of the shielding effect was 1.75 dB / μm at a frequency of 1 MHz and 3.78 dB / μm at a frequency of 10 MHz. As shown in Table 5, the gradient of the shielding effect was a positive value of 4.97 in the lower frequency range from 1 MHz to 10 MHz.

[0057] As shown in Table 3, the shielding material of specimen 4 (example of the present invention) had a shielding effect SE of 1 MHz. １Ｍ is 47.81 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 86.76 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ reached the measurement limit. As shown in Table 4, the efficiency of the shielding effect was 1.49 dB / μm at a frequency of 1 MHz and 2.71 dB / μm at a frequency of 10 MHz. As shown in Table 5, the gradient of the shielding effect was a positive value of 4.33 in the lower frequency range from 1 MHz to 10 MHz.

[0058] As shown in Table 3, the shielding material of specimen 5 (comparative example) had a shielding effect SE of 1 MHz. １Ｍ is 38 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 32 dB, and the shielding effect SE at a frequency of 100 MHz１００Ｍ The shielding effectiveness is 23 dB. As shown in Table 4, the efficiency of the shielding effect is 1.85 dB / μm at a frequency of 1 MHz, 1.56 dB / μm at a frequency of 10 MHz, and 1.12 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness is a negative value of −0.67 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a negative value of −0.10 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a negative value of −0.15 over the entire frequency range of 1 MHz to 100 MHz.

[0059] As shown in Table 3, the shielding material of specimen 6 (comparison example) had a shielding effect SE of 1 MHz. １Ｍ is 15 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 17 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ The shielding effectiveness is 11 dB. As shown in Table 4, the efficiency of the shielding effect is 0.73 dB / μm at a frequency of 1 MHz, 0.83 dB / μm at a frequency of 10 MHz, and 0.54 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness is a positive value of 0.22 dB / MHz in the lower frequency range from 1 MHz to 10 MHz, a negative value of −0.07 dB / MHz in the higher frequency range from 10 MHz to 100 MHz, and a negative value of −0.15 over the entire frequency range from 1 MHz to 100 MHz.

[0060] As shown in Table 3, the Cu foil of specimen 7 (comparison example) had a shielding effect SE at a frequency of 1 MHz. １Ｍ is 23.56 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 43.16 dB, and the shielding effect SE at a frequency of 100 MHz １００ＭThe shielding effectiveness was 64.13 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 2.36 dB / μm at a frequency of 1 MHz, 4.32 dB / μm at a frequency of 10 MHz, and 6.41 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 2.18 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a positive value of 0.23 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a positive value of 0.41 dB / MHz over the entire frequency range of 1 MHz to 100 MHz.

[0061] As shown in Table 3, the Cu foil of specimen 8 (comparison example) had a shielding effect SE at a frequency of 1 MHz. １Ｍ is 29.68 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 49.46 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ The shielding effectiveness was 76.18 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 1.48 dB / μm at a frequency of 1 MHz, 2.47 dB / μm at a frequency of 10 MHz, and 3.81 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 2.20 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a positive value of 0.30 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a positive value of 0.47 dB / MHz over the entire frequency range of 1 MHz to 100 MHz.

[0062] As shown in Table 3, the Cu foil of specimen 9 (comparative example) had a shielding effect SE at a frequency of 1 MHz. １Ｍ is 33.37 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 53.82 dB, and the shielding effect SE at a frequency of 100 MHz １００ＭThe shielding effectiveness was 89.64 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 1.11 dB / μm at a frequency of 1 MHz, 1.97 dB / μm at a frequency of 10 MHz, and 2.99 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 2.27 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a positive value of 0.40 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a positive value of 0.57 dB / MHz over the entire frequency range of 1 MHz to 100 MHz.

[0063] As shown in Table 3, the PC permalloy foil of specimen 10 (comparative example) had a shielding effect SE of 1 MHz. １Ｍ is 16.02 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 33.85 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ The shielding effectiveness was 57.32 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 1.60 dB / μm at a frequency of 1 MHz, 3.39 dB / μm at a frequency of 10 MHz, and 5.73 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 1.98 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a positive value of 0.26 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a positive value of 0.42 dB / MHz over the entire frequency range of 1 MHz to 100 MHz.

[0064] As shown in Table 3, the PC permalloy foil of specimen 11 (comparative example) had a shielding effect SE at a frequency of 1 MHz. １Ｍ is 24.92 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 54.63 dB, and the shielding effect SE at a frequency of 100 MHz １００ＭThe shielding effectiveness was 84.40 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 1.31 dB / μm at a frequency of 1 MHz, 2.88 dB / μm at a frequency of 10 MHz, and 4.44 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 3.30 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a positive value of 0.33 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a positive value of 0.60 dB / MHz over the entire frequency range of 1 MHz to 100 MHz.

[0065] As shown in Table 3, the PC permalloy foil of specimen 12 (comparative example) had a shielding effect SE of 1 MHz. １Ｍ is 26.54 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 57.97 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ The shielding effectiveness was 88.90 dB. As shown in Table 4, the efficiency of the shielding effectiveness was 1.33 dB / μm at a frequency of 1 MHz, 2.90 dB / μm at a frequency of 10 MHz, and 4.45 dB / μm at a frequency of 100 MHz. As shown in Table 5, the gradient of the shielding effectiveness was a positive value of 3.49 dB / MHz in the lower frequency range of 1 MHz to 10 MHz, a positive value of 0.34 dB / MHz in the higher frequency range of 10 MHz to 100 MHz, and a positive value of 0.63 dB / MHz over the entire frequency range of 1 MHz to 100 MHz.

[0066] As shown in Table 3, the PC permalloy foil of specimen 13 (comparative example) had a shielding effect SE at a frequency of 1 MHz. １Ｍ is 40.24 dB, and the shielding effect SE at a frequency of 10 MHz １０Ｍ is 81.00 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ reached the measurement limit. As shown in Table 4, the efficiency of the shielding effect was 1.34 dB / μm at a frequency of 1 MHz and 2.70 dB / μm at a frequency of 10 MHz. As shown in Table 5, the gradient of the shielding effect was a positive value of 4.53 dB / MHz in the lower frequency range from 1 MHz to 10 MHz.

[0067] From the above, in the shielding effect measured using a magnetic field shield evaluation device according to the KEC method, the shielding materials of test pieces 1 to 4 (examples of the present invention) had a shielding effect SE of 10 MHz at a frequency of 10 MHz. １０Ｍ is 50 dB or more, and the efficiency of the shielding effect at a frequency of 1 MHz, that is, the shielding effect SE at a frequency of 1 MHz １Ｍ It was confirmed that the shielding effect SE at a frequency of 1 MHz was 1.4 dB / μm or more. １Ｍ It was confirmed that the shielding effect SE at a frequency of 100 MHz was 25 dB or more. １００Ｍ It was confirmed that the shielding effect SE at a frequency of 10 MHz was 70 dB or more. １０Ｍ It was confirmed that the difference between the shielding effectiveness and the efficiency of the shielding effectiveness was 2.7 dB / μm or more. It was also confirmed that the gradient of the shielding effectiveness was positive in all frequency ranges from 1 MHz to 10 MHz, from 10 MHz to 100 MHz, and from 1 MHz to 100 MHz. This confirmed that the shielding materials of specimens 1 to 4 (examples of the present invention) were effective in the frequency range from 1 MHz to 100 MHz from the viewpoints of shielding effectiveness, efficiency of the shielding effectiveness, and gradient of the shielding effectiveness.

[0068] On the other hand, the shielding material of specimen 5 (comparative example) is clearly superior to the shielding material of specimen 6 (comparative example). Even the shielding material of specimen 5 has a shielding effect SE at a frequency of 10 MHz. １０Ｍ does not exceed 50 dB, and the shielding effect SE at a frequency of 100 MHz １００Ｍ does not exceed 70 dB, the efficiency of the shielding effect at a frequency of 10 MHz does not exceed 2.7 dB / μm, and the gradient of the shielding effect is a negative value in all frequency ranges from 1 MHz to 10 MHz, 10 MHz to 100 MHz, and 1 MHz to 100 MHz. Therefore, it was confirmed that the shielding materials of specimens 1 to 4 (invention examples) are superior to the shielding materials of specimens 5 and 6 (comparison examples) in terms of shielding effect, efficiency of the shielding effect, and gradient of the shielding effect in the frequency range from 1 MHz to 100 MHz.

[0069] In addition, the Cu foils of test pieces 7 to 9 (comparative examples) had a shielding effect SE of 10 MHz. １０Ｍ Even in the case of specimen 9, where the shielding effect is 50 dB or more, the efficiency of the shielding effect at a frequency of 1 MHz does not exceed 1.4 dB / μm. Therefore, it was confirmed that the shielding materials of specimens 1 to 4 (invention examples) are superior to the Cu foils of specimens 7 to 9 (comparative examples) in terms of shielding effect and efficiency of the shielding effect in the frequency range from 1 MHz to 100 MHz (particularly the lower frequency range from 1 MHz to 10 MHz).

[0070] In addition, among the PC permalloy foils (comparative examples) of specimens 10 to 13, specimen 10 had a shielding effect SE at a frequency of 10 MHz. １０Ｍ The shielding effect SE at a frequency of 10 MHz does not exceed 50 dB. １０Ｍ Even for specimens 11 to 13, where the shielding effect is 50 dB or more, the efficiency of the shielding effect at a frequency of 1 MHz does not exceed 1.4 dB / μm. Therefore, it was confirmed that the shielding materials of specimens 1 to 4 (invention examples) are superior to the PC permalloy foils of specimens 10 to 13 (comparison examples) in terms of shielding effect and efficiency of the shielding effect in the frequency range from 1 MHz to 100 MHz (particularly the lower frequency range from 1 MHz to 10 MHz).

Claims

1. A conductive layer having a total thickness Tc made of a copper plating film is laminated in the thickness direction of a magnetic layer having a total thickness Tm made of an iron-nickel soft magnetic material containing 70% by mass or more and 85% by mass or less of nickel, and the shielding effect measured using a magnetic field shield evaluation device according to the KEC method is a shielding effect SE at a frequency of 10 MHz. １０Ｍ is 50 dB or more, and the shielding effect SE at a frequency of 1 MHz is １Ｍ / (Tm+Tc) is 1.4 dB / μm or more.

2. The shielding material according to claim 1, wherein the magnetic layer satisfies 10 μm≦Tm≦30 μm, and the conductive layer satisfies 0.05≦Tc / Tm≦0.

2.

3. The shielding effect measured using a magnetic shield evaluation device according to the KEC method is SE at a frequency of 1 MHz. １Ｍ The shielding material according to claim 1 or 2, wherein the shielding effect is 25 dB or more.

4. The shielding effect measured using a magnetic shield evaluation device according to the KEC method is SE at a frequency of 100 MHz. １００Ｍ The shielding material according to claim 1 or 2, wherein the shielding effect is 70 dB or more.

5. The shielding effect measured using a magnetic shield evaluation device according to the KEC method is SE at a frequency of 10 MHz. １０Ｍ 3. The shielding material according to claim 1, wherein / (Tm+Tc) is 2.7 dB / μm or more.

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