Coil and coil components

Abstract

To provide a coil and coil components which can reduce manufacturing cost.SOLUTION: A coil 10 includes: parts 22, 24, 32, 34, 36 formed by holding a copper foil L2 between a film-like base material L1 made of polyimide resin and a coverlay film L4; and connectors 22B, 24B, 32A, 32B, 34A, 34B, 36A, 36B attached to the parts 22, 24, 32, 34, 36. The parts 22, 24, 32, 34, 36 are connected by the connectors 22B, 24B, 32A, 32B, 34A, 34B, 36A, 36B and are not therefore in contact with one another.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a coil and coil components.

Background Art

[0002] When a high-frequency current is passed through a conductor such as a coil, it is known that a skin effect occurs where the current flows only near the surface of the conductor. For this reason, the electrical resistance increases in a conductor with a circular cross-section. On the other hand, in the case of a conductor having a rectangular cross-section such as a flat copper wire, the influence of the skin effect is relatively less than that of a conductor with a circular cross-section, so it becomes possible to pass a larger current. Therefore, an edgewise coil formed by bending a flat copper wire or the like in the short side direction is used.

[0003] For example, Patent Document 1 discloses an edgewise coil in which the heat dissipation is improved by making it possible for air to move inside the conductor by using a flat conductor (flat copper wire) having a hollow structure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When manufacturing the edgewise coil described in Patent Document 1 above, it is necessary to bend a flat copper wire in the short side direction, which is difficult to bend, using a mold or the like, so the manufacturing is laborious and the manufacturing cost tends to increase.

[0006] The present invention provides a coil and coil components capable of reducing the manufacturing cost.

Means for Solving the Problems

[0007] The coil according to the present invention includes a plurality of coil components each having a film body formed by sandwiching a conductive thin film between insulating thin films and a connector attached to the film body, and the plurality of coil components are configured such that the film bodies are not in close contact with each other by being connected via both connectors.

[0008] In the coil according to the present invention, the plurality of coil components may be arranged in a stacked state.

[0009] In the coil according to the present invention, the connector may be attached to the front surface or the back surface of the film body.

[0010] The coil component according to the present invention may be the coil component constituting the coil of the above invention.

Effect of the Invention

[0011] According to the coil of the present invention, since the coils can be manufactured by connecting the coil components formed by overlapping the thin films with each other, the manufacturing cost can be reduced.

[0012] According to the coil component of the present invention, the manufacturing cost in coil manufacturing can be reduced.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

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Figure 8

Figure 9

Figure 10

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DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, the coil 10 according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1(a) is a diagram showing the overall configuration of the coil 10 in the present embodiment. FIG. 1(b) is a diagram showing the configuration of the coil 10 when viewed from the A direction shown in FIG. 1(a). FIG. 1(c) is a diagram showing a state in which each part constituting the coil 10 shown in FIG. 1(a) is disassembled.

[0015] As shown in FIGS. 1(a) to 1(c), the coil 10 is an element including linear parts with terminals (film body, coil parts) 22 and 24 provided with terminals 22A and 24A on one end side, and an annular part 30 (which can also be expressed as a surrounding part). As shown in FIG. 1(c), the linear part 22 with terminals is a film-like part in a strip shape provided with a terminal 22A on one end side and a convex connector (connection part) 22B on the surface of the other end side. On the other hand, the linear part 24 with terminals is a film-like part in a strip shape provided with a terminal 24A on one end side and a concave connector (connection part) 24B on the back surface of the other end side.

[0016] As shown in FIGS. 1(a) and 1(b), the annular part 30 is configured by connecting two upper parts (film body, coil parts) 32 and 34 and one lower part (film body, coil parts) 36 to each other. The upper parts 32 and 34 are film-like members having a substantially semi-annular (in other words, semi-circular arc shape) outer shape provided with concave connectors (connection parts) 32A and 34A on the back surface of the left end side and convex connectors (connection parts) 32B and 34B on the surface of the right end side. As shown in FIG. 1(b), the upper parts 32 and 34 are arranged such that the upper part 34 overlaps the upper part 32 when viewed from the A direction. On the other hand, as shown in FIG. 1(c), the lower part 36 is a film-like member having a substantially semi-annular (in other words, semi-circular arc shape) presenting a convex connector (connection part) 36A on the surface of the left end side and a concave connector (connection part) 36B on the back surface of the right end side.

[0017] All of the above-mentioned convex connectors 22B, 32B, 34B, 36A have the same configuration and are each detachably configured with the concave connectors 24B, 32A, 34A, 36B. The convex connectors 22B, 32B, 34B, 36A and the concave connectors 24B, 32A, 34A, 36B have the role of electrically connecting the respective parts 22, 24, 32, 34, 36 when connected to each other.

[0018] Figs. 2(a) to 2(c) are diagrams showing the assembly procedure of the coil 10. As shown in Fig. 2(a), first, the male connector 22B (see Fig. 1(c)) provided on the other end side surface of the above-described linear part 22 with terminals is connected to the female connector 32A (see Fig. 1(c)) provided on the back surface of the left end side of the upper part 32. Next, as shown in Fig. 2(b), the male connector 32B (see Fig. 2(a)) on the right end side surface of the upper part 32 is connected to the female connector 36B (see Fig. 1(c)) provided on the back surface of the right end side of the lower part 36. Subsequently, as shown in Fig. 2(c), the male connector 36A (see Fig. 2(b)) on the left end side surface of the lower part 36 is connected to the female connector 34A (see Fig. 1(c)) provided on the back surface of the left end side of the upper part 34. And finally, the male connector 34B provided on the right end side surface of the upper part 34 shown in Fig. 2(c) is connected to the female connector 24B provided on the back surface of the other end side of the linear part 24 with terminals. By connecting the male connectors 22B, 32B, 34B, 36A and the female connectors 24B, 32A, 34A, 36B provided on each of the parts 22, 24, 32, 34, 36 to each other, the coil 10 is configured.

[0019] In the present embodiment, the connectors 32B and 36B of the upper part 32 and the lower part 36 are connected to each other, and the connectors 36A and 34A of the upper part 34 and the lower part 36 are connected to each other to form the annular part 30. However, the upper parts 32 and 34 and the lower part 36 may be integrally configured without using connectors.

[0020] Next, the internal structure of the coil 10 will be described. Here, since the linear parts 22 and 24 with terminals and the upper parts 32 and 34 and the lower part 36, which are the components of the coil 10 described above, have substantially the same internal structure, the internal structure of the coil 10 will be described by taking the upper part 32 as an example, and the description of the internal structures of the other parts 22, 24, 34, and 36 will be omitted as appropriate. Fig. 1(d) is a diagram schematically showing the cross-sectional configuration of the upper part 34.

[0021] As shown in FIG. 1(d), the upper part 34 has a laminated structure formed by laminating a base material (insulating thin film) L1, a copper foil (conductive thin film) L2, an adhesive layer L3, and a coverlay film (insulating thin film) L4 in this order, and has flexibility. The base material L1 of the upper part 34 is composed of an insulating film such as a polyimide resin, and the copper foil L2 is pressure-bonded and fixed to the surface side. In FIG. 1(d), both end faces of the copper foil L2 are exposed to schematically show the cross-sectional configuration of the upper part 34. However, actually, both end faces of the copper foil L2 are also covered by the base material L1 and the coverlay film L4 so as not to be exposed to the outside.

[0022] The copper foil L2 has a thickness of 35 μm as an example, and is provided so as to be electrically connected to a concave connector 34A attached to the back surface (the surface formed by the base material L1) of the upper part 34 and a convex connector 34B attached to the front surface (the surface formed by the coverlay film L4) of the upper part 34, respectively. The copper foil L2 is plated on the surface, that is, the surface on the adhesive layer L3 side, for corrosion prevention. The coverlay film L4 is a protective film composed of an insulating resin such as a polyimide resin like the base material L1, and is adhesively fixed so as to cover the copper foil L2 via the adhesive layer L3. In this way, the copper foil L2 is laminated in a state of being sandwiched between the base material L1 and the coverlay film L4.

[0023] Also, there is an advantage that the copper foil L2 can be prevented from being broken by vibration or the like by pressure-bonding and covering the copper foil L2 so as to be sandwiched between the coverlay film L4 and the base material L1 as described above.

[0024] According to the coil 10 of the first embodiment, the upper parts 32, 34, the lower part 36, and the linear parts 22, 24 with terminals, which are formed by sandwiching the copper foil L2 between the base material L1 and the coverlay film L4, are connected to each other. Therefore, for example, it is possible to manufacture the coil without using a mold as in the case of manufacturing the coil using a flat copper wire. As a result, the manufacturing cost of the coil 10 can be reduced.

[0025] Also, according to the coil 10, by using the copper foil L2 as a conductor, it is possible to reduce the eddy current due to the skin effect. As a result, the electrical resistance generated when a high-frequency current flows through the copper foil L2 can also be reduced.

[0026] Since the coil 10 in the above first embodiment has flexibility, the distance between the upper parts 32 and 34 can be adjusted by sandwiching a spacer or the like between the overlapping upper parts 32 and 34. Thereby, it is also possible to adjust the amount of inductance of the coil 10.

[0027] In the above first embodiment, a copper foil L2 having a thickness of 35 μm is used as the conductive thin film, but the present invention is not limited thereto. The thickness of the copper foil L2 may be 250 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less. Even in this case, the electrical resistance generated when a high-frequency current flows through the copper foil L2 can be reduced.

[0028] FIG. 3 is a diagram schematically showing a side configuration of the coil 10 when viewed from the B direction shown in FIG. 1(A). As shown in FIG. 3, the linear part 24 with terminals and the upper part 34 constituting a part of the annular part 30 are connected via a concave connector 24B and a convex connector 34B so that both ends overlap each other. Here, at least one of the convex connector 34B and the concave connector 24B is provided so as to slightly protrude from the front or back surface of the linear part 24 with terminals.

[0029] Here, if the linear part 24 with terminals and the upper part 34 overlap in a state of being in close contact, the base material L1 of the linear part 24 with terminals, which is an insulator, and the coverlay film L4 of the upper part 34 are sandwiched between the copper foils L2 of both the linear part 24 with terminals and the upper part 34. When a high-frequency AC power supply is applied in such a state, the floating (parasitic) capacitance increases and the transmission loss increases.

[0030] Therefore, in the coil 10 of the present embodiment, as shown in FIG. 3, in a state where both connectors 24B and 34B are connected, a gap t is formed between the linear part 24 with terminals and the upper part 34. As a result, the linear part 24 with terminals and the upper part 34 are held in a separated state without being in close contact, so an increase in the stray capacitance can be suppressed. As a result, an increase in transmission loss in wireless power transmission using a high-frequency power supply can be suppressed. In the present embodiment, the size of the gap t is set to be 0.7 mm as an example, but the size of the gap t may be less than 0.7 mm or may be larger than 0.7 mm.

[0031] Similarly, the upper part 34 and the lower part 36 are connected via the concave connector 34A and the convex connector 36A, the lower part 36 and the upper part 32 are connected via the concave connector 36B and the convex connector 32B, and the upper part 32 and the linear part 22 with terminals are connected via the concave connector 32A and the convex connector 22B. A gap having the same size as the gap t is also formed between the respective parts 22, 32, 34, and 36. For this reason, the upper parts 32 and 34 and the lower part 36 are held in a non-contact state. Thereby, an increase in the stray capacitance can be suppressed. Further, as described above, the heat dissipation can also be improved by providing a gap between the respective parts 22, 24, 32, 34, and 36 and connecting them.

[0032] Note that the gap between the respective parts 22, 24, 32, 34, and 36 may be more firmly secured and made less likely to contact each other by sandwiching a spacer between the respective parts 22, 24, 32, 34, and 36.

[0033] Furthermore, in the first embodiment, the number of turns of the annular portion 30 is 1.5 turns, that is, the annular portion 30 is configured using two upper parts 32 and 34 and one lower part 36, but the present invention is not limited to this. For example, the coil may be configured such that the number of turns of the annular portion 30 is two or more by increasing the number of the upper parts 32 and 34 and the lower part 36 constituting the annular portion 30.

[0034] In the above-described first embodiment, an example has been described in which the copper foils L2 are attached only to one side of the base material L1 to form the upper parts 32 and 34, the lower part 36, and the straight parts 22 and 24 with terminals. However, the present invention is not limited to this. For example, the upper parts 32 and 34, the lower part 36, and the straight parts 22 and 24 with terminals may be formed by pressure-bonding and fixing copper foils to both sides of the base material, respectively. The cross-sectional configuration of each of the above parts 22, 24, 32, 34, and 36 according to the first modification in this case will be described by taking the upper part 34 as an example. FIG. 1(e) is a diagram schematically showing the cross-sectional configuration of the upper part 34 according to the first modification in this case.

[0035] As shown in FIG. 1(e), the upper part 34 has a cross-sectional structure in which copper foils M3 and M5 are pressure-bonded and fixed to both sides of the base material M4, and further, coverlay films M1 and M7 cover the copper foils M3 and M5 via adhesive layers M2 and M6, respectively. The surfaces of the copper foils M3 and M5 are plated in the same manner as the copper foil L2 according to the first embodiment. Each of the parts 22, 24, 32, and 36 also has a cross-sectional configuration substantially the same as that of the above-described upper part 34. Further, in some or all of the parts 22, 24, 32, 34, and 36, through holes may be provided in the base material M4 and plating may be performed in the holes to electrically connect the copper foils M3 and M5 to each other.

[0036] In the above-described first embodiment, the case where the copper foil L2 is used as the conductive thin film has been described as an example. However, a material having conductivity other than copper may be used as the conductive thin film.

[0037] In the above-described first embodiment, the case where the polyimide resin is used as the base material L1 and the coverlay film L4 has been described as an example. However, depending on the product specifications and the like, an insulating resin other than the polyimide resin may be used to form the base material L1 and the coverlay film L4.

[0038] In the above first embodiment, an example in which the coil 10 is configured using two upper parts 32 and 34 and one lower part 36 has been described. However, the present invention is not limited to this. For example, the coil 40 may be configured using an annular part 31 composed of the upper part 32 and the lower part 36. The configuration of the coil 40 according to the second modification in this case will be described with reference to FIGS. 4(a) and 4(b). In the following description, the same components as those of the coil 10 in the above first embodiment will be denoted by the same reference numerals as appropriate, and the description thereof will be omitted as appropriate, and mainly the different parts of the configuration will be described.

[0039] FIG. 4(a) is a plan view showing the configuration of the coil 40 in the second modification, and FIG. 4(b) is a view showing the coil 40 in a disassembled state. As shown in FIGS. 4(a) and 4(b), the coil 40 is composed of an annular part 31 and straight parts 22 and 24 with terminals. The annular part 31 includes the upper part 32 and the lower part 36. A convex connector 22B provided on the other end side surface of the straight part 22 with a terminal is connected to a concave connector 32A on the back surface of the left end side of the upper part 32. A convex connector 32B on the right end side surface of the upper part 32 is connected to a concave connector 36B on the back surface of the right end side of the lower part 36. A convex connector 36A on the left end side surface of the lower part 36 is connected to a concave connector 24B provided on the back surface of the other end side of the straight part 24 with a terminal. Also in the coil 40 in this case, the same effects as those of the coil 10 in the above first embodiment can be obtained.

[0040] In the above-described first embodiment, an example in which the coil 10 is configured using the upper parts 32 and 34 and the lower part 36 has been described. However, the present invention is not limited to this. For example, instead of using curved parts such as the upper parts 32 and 34 and the lower part 36, the coil may be configured using linearly configured parts. The configuration of the coil 50 of the second embodiment in this case will be described with reference to FIGS. 5(a) and 5(b). In the following description, the same reference numerals will be appropriately assigned to the same components as those of the coil 10 of the first embodiment, and the description thereof will be omitted, and mainly the different parts of the configuration will be described.

[0041] FIG. 5(a) is a plan view showing the configuration of the coil 50 in the second embodiment, and FIG. 5(b) is a view showing the coil 50 in a disassembled state. As shown in FIGS. 5(a) and 5(b), the coil 50 includes terminal-attached linear parts (film body, coil component) 61 and 62 and five linear parts (film body, coil component) 63, 64, 65, 66, and 67. In the present embodiment, the terminal-attached linear part 61 has the same configuration as the linear part 22 described above, a terminal 61A is provided on one end side, and a convex connector (connection part) 61B is provided on the surface of the other end side. On the other hand, the terminal-attached linear part 62 has the same configuration as the linear part 24 described above, a terminal 62A is provided on one end side, and a concave connector (connection part) 62B is provided on the back surface of the other end side.

[0042] As shown in FIG. 5(b), the linear parts 63 to 67 have substantially the same functions and configurations as the upper part 34 and are formed linearly. The linear parts 63 to 67 are provided with concave connectors (connection parts) 63A to 67A on the back surface of one end side, and convex connectors (connection parts) 63B to 67B on the front surface of the other end side. The concave connectors 62B, 63A to 67A have the same functions as the concave connector 32A in the upper part 32 of the first embodiment, and are configured to be detachable from the convex connectors 61B, 63B to 67B respectively. The concave connectors 62B, 63A to 67A serve to electrically connect the linear parts 63 to 67 by being connected to the convex connectors 61B, 63B to 67B.

[0043] The convex connector 61B provided on the front surface of the other end side of the linear part 61 with a terminal described above is connected to the concave connector 63A on the back surface of one end side of the linear part 63 in a state where the two parts 61 and 63 form a substantially right angle. The convex connector 63B on the front surface of the other end side of the linear part 63 is connected to the concave connector 64A provided on the back surface of one end side of the linear part 64 in a state where the two parts 63 and 64 form a substantially right angle. The convex connector 64B on the front surface of the other end side of the linear part 64 is connected to the concave connector 65A provided on the back surface of one end side of the linear part 65 in a state where the two parts 64 and 65 form a substantially right angle. The convex connector 65B provided on the front surface of the other end side of the linear part 65 is connected to the concave connector 66A provided on the back surface of one end side of the linear part 66 in a state where the two parts 65 and 66 form a substantially right angle. The convex connector 66B on the front surface of the other end side of the linear part 66 is connected to the concave connector 67A provided on the back surface of one end side of the linear part 67 in a state where the two parts 66 and 67 form a substantially right angle. The convex connector 67B provided on the front surface of the other end side of the linear part 67 is connected to the concave connector 62B provided on the back surface of one end side of the linear part 62 with a terminal in a state where the two parts 62 and 67 form a substantially right angle. By connecting the linear parts 63, 64, 65, 66, 67 to each other in order to form a substantially right angle as described above, a coil 50 having a substantially square frame-like external shape can be manufactured.

[0044] Also in the coil 50 in the second embodiment in this case, the same effects as those of the coil 10 in the first embodiment can be obtained.

[0045] In the above first embodiment, an example of configuring the coil 10 using the upper parts 32, 34 and the lower part 36 has been described, but the present invention is not limited to this. For example, a coil may be configured using curved parts like the upper parts 32, 34 and the lower part 36 and parts configured linearly. The configuration of the coil 70 in the third embodiment in this case will be described with reference to FIGS. 6(a) to 7(e). In the following description, the same components as those of the coil 10 in the first embodiment will be denoted by the same reference numerals as appropriate and the description thereof will be omitted, and mainly the different parts of the configuration will be described.

[0046] FIG. 6(a) is a plan view showing the configuration of the coil 70 in the third embodiment, and FIG. 6(b) is a view showing the coil 70 in a disassembled state. As shown in FIGS. 6(a) and 6(b), the coil 70 includes an annular portion 80 having a rounded rectangular outer shape, and linear parts with terminals (film body, coil component) 81, 82. The annular portion 80 includes two linear parts (film body, coil component) 83, 84, two upper parts 85, 86 (film body, coil component), and one lower part 87 (film body, coil component).

[0047] In this embodiment, the linear part 81 with terminals has the same configuration as the above-described linear part 22, with a terminal 81A provided on one end side and a male connector (connection part) 81B provided on the surface of the other end side. On the other hand, the linear part 82 with terminals has the same configuration as the above-described linear part 24, with a terminal 82A provided on one end side and a female connector (connection part) 82B provided on the back surface of the other end side. The linear parts 83 and 84 have the same functions and configurations as the upper part 34 and are different in that they are formed linearly. The linear parts 83 and 84 have female connectors (connection parts) 83A and 84A provided on the back surface of one end side, and male connectors (connection parts) 83B and 84B provided on the surface of the other end side, respectively. The upper parts 85 and 86 have the same functions and configurations as the upper part 34, and the lower part 87 has the same functions and configurations as the lower part 36.

[0048] Figures 7(a) to 7(e) are diagrams showing the assembly procedure of the coil 10. As shown in Figure 7(a), the male connector 81B (see Figure 6(b)) provided on the surface of the other end side of the above-described linear part 81 with terminals is connected to the female connector (connection part) 85A (see Figure 6(b)) provided on the back surface of the left end side of the upper part 85. Next, as shown in Figure 7(b), the male connector (connection part) 85B (see Figure 7(a)) on the surface of the right end side of the upper part 85 is connected to the female connector 83A provided on the back surface of one end side of the linear part 83. Then, as shown in Figure 7(c), the male connector 83B (see Figure 7(b)) provided on the surface of the other end side of the linear part 83 is connected to the female connector (connection part) 87B (see Figure 6(b)) provided on the back surface of the right end side of the lower part 87. Subsequently, as shown in Figure 7(d), the male connector (connection part) 87A (see Figure 7(c)) on the surface of the left end side of the lower part 87 is connected to the female connector 84A (see Figure 6(b)) provided on the back surface of one end side of the linear part 84.

[0049] Then, as shown in FIG. 7(e), a convex connector 84B (see FIG. 7(d)) provided on the other end surface of the straight part 84 is connected to a concave connector (connection part) 86A (see FIG. 6(b)) provided on the back surface of the left end side of the upper part 86. Finally, a concave connector 82B provided on the back surface of the other end side of the straight part 82 with a terminal is connected to a convex connector (connection part) 86B provided on the surface of the right end side of the upper part 86. By connecting the convex connectors 81B, 83B, 84B, 85B, 86B, 87A and the concave connectors 82B, 83A, 84A, 85A, 86A, 87B provided on each of the parts 81 to 87 to each other, the coil 70 is configured.

[0050] Also in the coil 70 in the third embodiment in this case, the same effects as those of the coil 10 in the first embodiment can be obtained.

[0051] In the above first to third embodiments, the coils 10, 40, 70 are described as examples. However, the present invention is not limited to coils having a so-called surrounding shape that surrounds the periphery, such as an annular shape or a square frame shape like the coils 10, 40, 70. For example, the present invention may be applied to a coil configured by a non-surrounding shape. The configuration of the coil 90 in the fourth embodiment in this case will be described with reference to FIGS. 8(a) and 8(b). In the following description, the same reference numerals will be appropriately given to the same components as those of the coil 10 in the first embodiment, and the description thereof will be omitted, and mainly the different parts of the configuration will be described.

[0052] FIG. 8(a) is a diagram showing the overall configuration of the coil 90. FIG. 8(b) is a diagram showing the coil 90 in a disassembled state in FIG. 8(a). As shown in FIGS. 8(a) and 8(b), the coil 90 is a coil configured by a meandering shape, that is, a so-called meander wiring. The coil 90 includes straight parts with terminals (film body, coil parts) 91, 92, four straight parts (film body, coil parts) 93, 94, 95, 96, three upper parts 101, 102, 103, and two lower parts 104, 105.

[0053] The linear part 91 with terminals has the same configuration as the above-described linear part 22, and a terminal 91A is provided on one end side, and a convex connector (connection part) 91B is provided on the surface of the other end side. On the other hand, the linear part 92 with terminals has the same configuration as the above-described linear part 24, and a terminal 92A is provided on one end side, and a concave connector (connection part) 92B is provided on the back surface of the other end side.

[0054] Since the linear parts 93 to 96 have the same configuration, the linear part 93 will be mainly taken as an example for explanation, and the explanations for the linear parts 94 to 96 will be omitted as appropriate. The linear part 93 has the same function and configuration as the upper part 34 and is formed in a linear shape. The linear part 93 is provided with a concave connector (connection part) 93A on the back surface of one end side, and a convex connector (connection part) 93B is provided on the surface of the other end side.

[0055] Since the upper parts 101 to 103 all have the same configuration, in the following explanation, the upper part 101 will be taken as an example for explanation, and the explanations for the upper parts 102 and 103 will be omitted as appropriate. The upper part 101 has the same function and configuration as the upper part 34, and a concave connector (connection part) 101A is provided on the back surface of the left end side, and a convex connector (connection part) 101B is provided on the surface of the right end side.

[0056] Also, since the lower parts 104 and 105 have the same configuration and function, in the following explanation, the lower part 104 will be described, and the explanation for the lower part 105 will be omitted as appropriate. The lower part 104 has a convex connector (connection part) 104B on the surface of the right end side, and has substantially the same function and configuration as the lower part 36 except that a concave connector (connection part) 104A is provided on the back surface of the left end side.

[0057] Next, the assembly procedure of the coil 90 will be described with reference to FIG. 8(a). As shown in FIG. 8(a), it is connected to the convex connector 91B provided on the other end side surface of the linear part 91 with a terminal and the concave connector 101A on the back surface of the left end side of the upper part 101. Then, the convex connector 101B on the right end side surface of the upper part 101 is connected to the concave connector 93A provided on the back surface of one end side of the linear part 93. Subsequently, the convex connector 93B provided on the other end side surface of the linear part 93 is connected to the concave connector 104A provided on the back surface of the left end side of the lower part 104.

[0058] Then, by the same procedure as above, as shown in FIG. 8(a), one end side of the linear part 94 is connected to the convex connector 104B provided on the right end side surface of the lower part 104, and the other end side of the linear part 94 is further connected to the left end side of the upper part 102. Next, one end side of the linear part 95 is connected to the right end side of the upper part 102, the other end side of the linear part 95 is connected to the left end side of the lower part 105, and the right end side of the lower part 105 is connected to one end side of the linear part 96. Subsequently, the other end side of the linear part 96 is connected to the left end side of the upper part 103, and the right end side of the upper part 103 is connected to the concave connector 92B provided on the back surface of the other end side of the linear part 92 with a terminal. Thus, the assembly of the coil 90 is completed.

[0059] Also in the coil 90 in the fourth embodiment in this case, the same effects as those of the coil 10 in the first embodiment can be obtained.

[0060] Subsequently, the coil 110, which is a simulation model of the coil 10 according to the first embodiment, will be described with reference to FIG. 9. FIG. 9 is a perspective view showing the configuration of the coil 110.

[0061] As shown in FIG. 9, the coil 110 has the same configuration as the coil 10 of the above embodiment, except that the number of turns of the annular part 120 is configured to be more than the number of turns of the annular part 30 of the coil 10 of the first embodiment in order to have an inductance value equivalent to the inductance values of the coil 200 according to Comparative Example 1 and the coil 300 according to Comparative Example 2, which will be described later.

[0062] Here, when the number of turns per one of the upper part 32 or the lower part 36 is expressed as 0.5, since the annular part 30 in the coil 10 of the first embodiment is composed of three upper parts 32, 34 and the lower part 36, the number of turns can be expressed as 1.5. On the other hand, the annular part 120 of the coil 110 is formed by sequentially connecting nine upper parts U1, U2, U3, … (hereinafter, appropriately referred to as "upper part U" when there is no need to particularly distinguish) having the same configuration as the upper part 32 and eight lower parts B1, B2, B3, ··· (hereinafter, appropriately referred to as "lower part B" when there is no need to particularly distinguish) in an annular shape. The number of turns of the annular part 120 can be expressed as 8.5.

[0063] Similar to the coil 10 of the first embodiment, in the coil 110, a gap having the same size as the above-described gap t (see FIG. 3) is formed between each of the parts U, B, 22, 24. By electrically connecting in a state where gaps are provided between each of the parts U, B, 22, 24, the cover lay film L4 constituting the front surface of each of the parts U, B, 22, 24 and the base material L1 constituting the back surface are not in close contact and are held with an air layer (gap) interposed therebetween.

[0064] Here, the relative permittivity of the cover lay film L4 and the base material L1 in the coil 110 is 4.3 and the dielectric tangent is 0.025. Therefore, if a high-frequency alternating voltage is applied in a state where the parts U, B, 22, 24 are in close contact without a gap, the cover lay film L4 and the base material L1 function as a capacitor, in other words, as a dielectric, and the transmission loss will increase.

[0065] On the other hand, by providing a gap without bringing the parts U, B, 22, 24 into close contact like the coil 110 according to the simulation model, it is possible to suppress the cover lay film L4 and the base material L1 from functioning as a dielectric. As a result, it is possible to reduce the occurrence of transmission loss that occurs during wireless power transmission using a high-frequency AC power supply.

[0066] Next, an electromagnetic field analysis simulation of the coil 110 and the coils 200 and 300 according to Comparative Examples 1 and 2 will be described with reference to FIGS. 10 to 14.

[0067] FIG. 10(a) is a perspective view showing the configuration of the coil 200 according to Comparative Example 1, and FIG. 10(b) is a view showing the unfolded state of the coil 200 according to Comparative Example 1. In FIG. 10(a), the state in which the first film LY1 to the fourth film LY4 are laminated is shown by a broken line. In FIG. 10(b), the copper foil portion disposed on the front surface side is shown by a solid line, and the copper foil portion disposed on the back surface side is shown by a broken line.

[0068] As shown in FIGS. 10(a) and 10(b), the coil 200 is configured by laminating the first film LY1 to the fourth film LY4 having a substantially rectangular shape in plan view. In the following description, the configurations of the first film LY1 and the third film LY3 are substantially the same, and the configurations of the second film LY2 and the fourth film LY4 are also substantially the same. In the following description, the configurations of the first film LY1 and the second film LY2 will be mainly described, and the descriptions of the third film LY3 and the fourth film LY4 will be appropriately omitted.

[0069] As shown in FIGS. 10(a) and 10(b), the first film LY1 includes a base material K1 having a substantially rectangular shape in plan view and a copper foil D1 having a spiral portion UZ1 disposed in a spiral shape on the front surface side of the base material K1. The second film LY2 includes a base material K2 having a substantially rectangular shape in plan view and a copper foil D2 having a spiral portion UZ2 disposed in a spiral shape on the back surface side of the base material K2. The interval DP between the copper foils D1 in the spiral portion UZ1 described above is set to 8 mm. Also, the spiral portion UZ2 is configured in the same manner as the spiral portion UZ1. Here, the base materials K1 and K2 have substantially the same configuration as the base material L1 in the above-described embodiment, and the copper foils D1 and D2 have substantially the same configuration as the copper foil L2. One end side of the copper foil D2 of the second film LY2 extends to the front surface side via a via (not shown) and is connected to one end side of the copper foil D1 of the first film LY1 described above.

[0070] The coil 200 is formed by folding the films LY1 to LY4 such that the front surface side of the first film LY1 and the front surface side of the second film LY2 are in contact, the back surface side of the second film LY2 and the back surface side of the third film LY3 are in contact, and the front surface side of the third film LY3 and the front surface side of the fourth film LY4 are in contact. As a result, the films LY1 to LY4 are laminated in a state of being in close contact with each other with the base materials K1 to K4 sandwiched between the copper foils D1 to D4 in the respective films LY1 to LY4. Also, in the following description, when there is no need for particular distinction, the copper foils D1 to D4 are appropriately referred to as "copper foil D".

[0071] FIG. 11(a) is a perspective view showing the configuration of the coil 300 according to Comparative Example 2, and FIG. 11(b) is a view showing the unfolded state of the coil 300 according to Comparative Example 2. In FIG. 11(b), the copper foil E1 disposed on the front surface side is shown by a solid line, and the copper foil E2 disposed on the back surface side is shown by a broken line. As shown in FIGS. 11(a) and 11(b), the coil 300 is configured by laminating the first film LM1 to the fifteenth film LM15 which are electrically connected, and has 7.5 turns.

[0072] Here, the odd-numbered layers, that is, the first film LM1, the third film LM3, ··· the fifteenth film LM15 all have the same configuration, and the even-numbered layers, that is, the second film LM2, the fourth film LM4, ··· the fourteenth film LM14 also all have the same configuration. In the following description, the odd-numbered layers will mainly be described with respect to the first film LM1, the even-numbered layers will mainly be described with respect to the second film LM2, and the description of the other films LM3 to LM15 will be omitted as appropriate. Also, for each of the films LM1 to LM15, when there is no need for particular distinction, they are appropriately referred to as "film LM".

[0073] The first film LM1 is provided with a copper foil E1 having a semi-circular portion convex downward on a substantially rectangular substrate J1 in plan view. The second film LM2 is provided with a copper foil E2 having a semi-circular portion convex upward on a substantially rectangular substrate J2 in plan view. The copper foil E1 of the first film LM1 and the copper foil E2 of the second film LM2 are electrically connected at the end side. Hereinafter, when there is no particular need for distinction, the substrates J1 to J15 of each film LM are appropriately denoted as "substrate J", and the copper foils E1 to E15 are appropriately denoted as "copper foil E".

[0074] Then, the surfaces of the odd-layer films LM and the surfaces of the even-layer films LM are in contact with each other, and the back surfaces of the even-layer films LM and the back surfaces of the odd-layer films LM are folded in order so that the substrates J are sandwiched between the copper foils E of each film LM. As a result, the substrates J are sandwiched between the copper foils E of each film LM and laminated, and the substrates J in each film LM are held in a state of being in close contact with each other. In this way, a coil 300 having a substantially annular shape in plan view as shown in FIG. 11(a) is formed.

[0075] FIG. 12 is a table showing the setting conditions and calculation results in the electromagnetic field analysis simulation. As shown in FIG. 12, the copper foil L2 of the coil 110 related to the simulation model, the copper foil D of the coil 200 related to Comparative Example 1, and the copper foil E of the coil 200 related to Comparative Example 2 are all set to have a width of 8 mm and a thickness of 0.095 mm.

[0076] FIG. 13 is a graph showing the relationship between the inductance value calculated by the above electromagnetic field analysis simulation and the frequency of the AC power supply to be supplied. The vertical axis represents the inductance value, and the horizontal axis represents the frequency of the power supply (voltage) to be applied. In FIG. 13, the curve of the calculated value of the coil 110 is shown by a solid line, the curve of the calculated value of the coil 200 is shown by a broken line, and the curve of the calculated value of the coil 300 is shown by a one-dot chain line.

[0077] As shown in FIGS. 12 and 13, when a high-frequency alternating current (voltage) power source of 13.56 MHz is applied, the inductance value of the coil 110 according to this embodiment is 2.17 μH, the inductance value of the coil 200 according to Comparative Example 1 is 2.20 μH, and the inductance value of the coil 300 according to Comparative Example 2 is 1.94 μH. All have substantially the same inductance value of around 2 μH.

[0078] Further, as shown in FIG. 13, when a high-frequency alternating current power source having a frequency higher than about 15 MHz is applied to the coil 200, the inductance value rapidly increases, and when a high-frequency alternating current power source having a frequency higher than about 30 MHz is applied to the coil 300, the inductance value rapidly increases. On the other hand, it can be seen that the inductance value of the coil 110 is almost constant up to around 40 MHz and increases from around 60 MHz.

[0079] Here, in wireless power transmission using a high-frequency alternating current power source, it is preferable for circuit design that the inductance value in the vicinity of 13.56 MHz, which is the power supply frequency of the high-frequency alternating current power source, does not fluctuate greatly and has a flat characteristic. For this reason, it can be said that the coil 110, whose inductance value is almost constant up to around 40 MHz and does not increase rapidly up to around 60 MHz, has the most preferable characteristics for wireless power transmission.

[0080] FIG. 14 is a graph showing the relationship between the Q value calculated by the above electromagnetic field analysis simulation and the frequency of the supplied alternating current power source. The vertical axis represents the Q value, and the horizontal axis represents the frequency of the applied power supply (voltage). In FIG. 14, the curve of the calculated value of the coil 110 is shown by a solid line, the curve of the calculated value of the coil 200 is shown by a broken line, and the calculated value of the coil 300 is shown by a one-dot chain line. Here, the Q value (quality factor of the coil) shown in FIG. 14 is a dimensionless parameter calculated based on the S parameter (Scattering Parameter) in the electromagnetic field analysis simulation, and the larger the value of the Q value, the less the transmission loss in wireless power transmission.

[0081] As shown in FIGS. 12 and 14, when a 13.56 MHz high-frequency alternating voltage used for wireless power transmission is applied, the Q value of the coil 200 according to Comparative Example 1 is 45, the Q value of the coil 300 according to Comparative Example 2 is 183, and the Q value of the coil 110 of the present embodiment is 387. From this, it is shown that the transmission loss of the coil 110 is the smallest.

[0082] Also, the self-resonant frequency of the coil 200 according to Comparative Example 1 is 23.0 MHz, the self-resonant frequency of the coil 300 according to Comparative Example 2 is 43.2 MHz, and the self-resonant frequency of the coil 110 is 82 MHz.

[0083] Here, FIG. 15 is a diagram showing an equivalent circuit of an inductor (coil) 400 when a high-frequency alternating voltage is applied. As shown in FIG. 15, the inductance 400L is the inductance of the inductor, the resistance 400R is the DC resistance in the inductor 400, and the inter-turn capacitance 400C is the inter-turn capacitance due to the (winding) structure of the inductor 400. When the inductance 400L is denoted as L and the inter-turn capacitance 400C is denoted as C, the following relationship shown in (Equation 1) holds with the self-resonant frequency f.

Equation

[0084] Also, the above-described inter-turn capacitance 400C has a large individual difference in each inductor, and the performance variation in the manufacturing process is likely to be large. Furthermore, in the vicinity of the self-resonant frequency in each inductor, the variation of the apparent inductance value with respect to the frequency becomes large, so it becomes difficult to exhibit stable performance as an inductor.

[0085] When considering the above points, it is desirable for suppressing transmission loss that the self-resonant frequency is at least five times the frequency to be used (13.56 MHz as described above in this embodiment), that is, 67.8 MHz or more in this embodiment.

[0086] Regarding this point, according to the above electromagnetic field analysis simulation, it is shown that the self-resonant frequency of the coil 110 is more than five times that of 13.56 MHz used for wireless power transmission.

[0087] Therefore, when the coil 110 is applied to wireless power transmission using a high-frequency power supply, it is possible to suppress transmission loss more than when the coils 200 and 300 are used. As described above, the coil 110 has performance suitable for wireless power transmission using a high-frequency power supply. Also, from this, it can be said that the coil 10 of the first embodiment has performance suitable for wireless power transmission using a high-frequency power supply, and the coils to which the first modification is applied, and the coils 40, 50, 70, 90 according to the second modification and the second to fourth embodiments also have performance suitable for wireless power transmission using a high-frequency power supply.

[0088] The present invention can also be implemented in various modified, corrected, or deformed forms based on the knowledge of those skilled in the art without departing from the spirit thereof. Also, within the range where the same action or effect is produced, it may be implemented in a form in which any of the invention-specific matters is replaced with other technologies.

Explanation of Reference Numerals

[0089] 10, 40, 50, 70, 90 Coils 22, 24, 61, 62 Linear parts with terminals (coil parts, film bodies) 22A, 24A, 61A, 62A, 81A, 82A, 91A, 92A Terminals 30, 31, 80, 120 Annular parts 32, 34, 85, 86, 101, 102, 103, U1, U2, U3, U Upper parts (coil parts, film bodies) 36,87,104,105,B1,B2,B3,B Lower parts (coil parts, film body) 22B,32B,34B,36A,61B,63B,64B,65B,66B 67B,81B,83B,84B,85B,86B,87A,91B,93B 101B,102B,104B Convex connector (connection part) 24B,32A,34A,36B,62B,63A,64A,65A,66A 67A,82B,83A,84A,85A,86A,87B,93A 101A,104A Concave connector (connection part) 63,64,65,66,67,83,84,93,94,95,96 Straight parts (coil parts, film body) L1,M4 Base material (insulating film) L2,M3,M5 Copper foil (conductive film) L3,M2,M6 Adhesive layer L4,M1,M7 Coverlay film (insulating film) 400 Inductor 400C Inter-winding capacitance 400L Inductance 400R Resistance t Gap

Claims

1. A coil component comprising a film body formed by sandwiching a conductive thin film between insulating thin films, and connectors attached to the film body, wherein a plurality of the coil components are configured such that the film bodies are not in close contact with each other by being connected via both of the connectors. Coil.

2. A plurality of the coil components are arranged in a stacked state, The coil according to claim 1.

3. The connector is attached to the front or back surface of the film body, The coil according to claim 1.

4. A coil component for constituting the coil according to claim 1.

Images