Coil, and coil component

Abstract

Provided are a coil and a coil component capable of reducing manufacturing costs. 【Solution means】The coil 10 includes parts 22, 24, 32, 34, 36 formed by sandwiching a copper foil L2 between a film-like base material L1 made of a 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 configured such that the parts 22, 24, 32, 34, 36 are not in close contact with each other by being connected via the connectors 22B, 24B, 32A, 32B, 34A, 34B, 36A, 36B.

Description

Technical Field

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

Background Art

[0002] When a high-frequency current flows 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 a flat conductor (flat copper wire) having a hollow structure is used to allow air to move inside the conductor, thereby improving heat dissipation.

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 process is laborious and the manufacturing cost tends to increase.

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

Means for Solving the Problems

[0007] The coil according to the present invention A first coil component composed of a first film body sandwiched between first conductive thin films and a first connector attached to the first film body, and a second coil component composed of a second film body formed by sandwiching a second conductive thin film between second insulating thin films and a second connector attached to the second film body and detachably provided with the first connector. When the first coil component and the second coil component are connected via the first connector and the second connector, a gap is formed between the first film body and the second film body.

[0008] In the coil according to the present invention The first film body and the second film body have flexibility may also be.

[0010] In the coil according to the present invention, the first connector and the second connector may be respectively disposed on the mutually facing surfaces of the first film body and the second film body. The coil component according to the present invention may be a coil component constituting the coil of the above invention.

Effect of the Invention

[0011] According to the coil of the present invention, since the coil can be manufactured by connecting coil components formed by laminating thin films to 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

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0014] Hereinafter, the coil 10 which is 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 this 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 the 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). The linear part 22 with terminals, as shown in FIG. 1(c), 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 portion 30 is configured by connecting two upper parts (film body, coil component) 32 and 34 and one lower part (film body, coil component) 36 to each other. The upper parts 32 and 34 are film-like members having a substantially semi-circular (in other words, semi-arc-shaped) outer shape with concave connectors (connection parts) 32A and 34A provided on the back surface on the left end side and convex connectors (connection parts) 32B and 34B provided on the front surface on 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-circular (in other words, semi-arc-shaped) shape with a convex connector (connection part) 36A provided on the front surface on the left end side and a concave connector (connection part) 36B provided on the back surface on the right end side.

[0017] The above-described convex connectors 22B, 32B, 34B, and 36A all have the same configuration and are each detachably configured with the concave connectors 24B, 32A, 34A, and 36B. The convex connectors 22B, 32B, 34B, and 36A and the concave connectors 24B, 32A, 34A, and 36B serve to electrically connect the respective parts 22, 24, 32, 34, and 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 convex 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 concave connector 32A (see Fig. 1(c)) provided on the left end side back surface of the upper part 32. Next, as shown in Fig. 2(b), the convex connector 32B (see Fig. 2(a)) on the right end side surface of the upper part 32 is connected to the concave connector 36B (see Fig. 1(c)) provided on the right end side back surface of the lower part 36. Subsequently, as shown in Fig. 2(c), the convex connector 36A (see Fig. 2(b)) on the left end side surface of the lower part 36 is connected to the concave connector 34A (see Fig. 1(c)) provided on the left end side back surface of the upper part 34. And finally, the convex connector 34B provided on the right end side surface of the upper part 34 shown in Fig. 2(c) is connected to the concave connector 24B provided on the other end side back surface of the linear part 24 with terminals. The coil 10 is configured by connecting the convex connectors 22B, 32B, 34B, 36A and the concave connectors 24B, 32A, 34A, 36B provided on the respective parts 22, 24, 32, 34, 36 to each other.

[0019] In this 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 formed 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, in actuality, 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 constituted by the base material L1) of the upper part 34 and a convex connector 34B attached to the front surface (the surface constituted 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. Thus, 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 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, it is possible to prevent the copper foil L2 from being broken due to vibration or the like.

[0024] According to the coil 10 of the first embodiment, the upper parts 32 and 34, the lower part 36, and the linear parts 22 and 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 a 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 the high-frequency current flows through the copper foil L2 can also be reduced.

[0026] Since the coil 10 in the first embodiment is flexible, 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 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 the high-frequency current flows through the copper foil L2 can be reduced.

[0028] FIG. 3 is a diagram schematically showing the 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 that constitutes a part of the annular part 30 are connected via the concave connector 24B and the 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 closely attached state, 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 straight part 24 with terminals and the upper part 34. Thereby, since the straight part 24 with terminals and the upper part 34 are held in a separated state without being in close contact, an increase in 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 straight part 22 with terminals are connected via the concave connector 32A and the convex connector 22B. Gaps having the same size as the gap t are 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 stray capacitance can be suppressed. Further, as described above, the heat dissipation performance can also be improved by providing gaps between the respective parts 22, 24, 32, 34, and 36 and connecting them.

[0032] Note that by sandwiching spacers between the respective parts 22, 24, 32, 34, and 36, the gaps between the respective parts 22, 24, 32, 34, and 36 can be more firmly secured so that they are less likely to come into contact with each other.

[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. However, 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 that constitute 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 linear 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 linear 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 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 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-described first embodiment, an example in which the coil 10 is constituted by 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 constituted by using the 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 reference numerals will be appropriately given to the same components as those of the coil 10 of the first embodiment, and the description will be appropriately omitted, 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 constituted by the annular part 31 and the straight parts 22 and 24 with terminals. The annular part 31 includes the upper part 32 and the lower part 36. The convex connector 22B provided on the other end side surface of the straight part 22 with a terminal is connected to the concave connector 32A on the back surface of the left end side of the upper part 32, the convex connector 32B on the right end side surface of the upper part 32 is connected to the concave connector 36B on the back surface of the right end side of the lower part 36, and the convex connector 36A on the left end side surface of the lower part 36 is connected to the 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 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, 34 and the lower part 36 has been described, but the present invention is not limited to this. For example, instead of using curved parts such as the upper parts 32, 34 and the lower part 36, the coil may be configured using linearly formed 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 components as those of the coil 10 of the first embodiment will be denoted by the same reference numerals as appropriate and the description thereof will be omitted, and mainly the different components 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 linear parts with terminals (film body, coil component) 61, 62 and five linear parts (film body, coil component) 63, 64, 65, 66, 67. In the present embodiment, the linear part 61 with a terminal 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 linear part 62 with a terminal 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 each configured to be detachable from the convex connectors 61B, 63B to 67B. The concave connectors 62B, 63A to 67A have a role of electrically connecting 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, and 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-described first embodiment, an example of configuring the coil 10 using the upper parts 32 and 34 and the lower part 36 has been described. However, the present invention is not limited thereto. For example, the coil may be configured using curved parts such as the upper parts 32 and 34 and the lower part 36 and straight parts. 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. Mainly, the parts having different configurations 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 components) 81 and 82. The annular portion 80 includes two linear parts (film body, coil components) 83 and 84, two upper parts 85 and 86 (film body, coil components), and one lower part 87 (film body, coil components).

[0047] In this embodiment, the linear part 81 with terminals has the same configuration as the linear part 22 described above. A terminal 81A is provided on one end side, and a male connector (connection part) 81B is 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 linear part 24 described above. A terminal 82A is provided on one end side, and a female connector (connection part) 82B is 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 are provided with female connectors (connection parts) 83A and 84A on the back surface of one end side, and male connectors (connection parts) 83B and 84B are respectively provided on the surface of the other end side. 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 linear part 81 with terminals described above 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 linear 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 linear 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 formed.

[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-described 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 components as those of the coil 10 in the first embodiment are denoted by the same reference numerals as appropriate and the description thereof is 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 linear parts with terminals (film body, coil component) 91, 92, four linear parts (film body, coil component) 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, 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, 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 description will be mainly given by taking the linear part 93 as an example, and the descriptions of 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 on the surface of the other end side.

[0055] Since the upper parts 101 to 103 all have the same configuration, in the following description, the upper part 101 will be taken as an example for explanation, and the descriptions of 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, 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 description, the lower part 104 will be described, and the description of 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 it has a concave connector (connection part) 104A on the back surface of the left end side.

[0057] Next, the assembly procedure of coil 90 will be described with reference to FIG. 8(a). As shown in FIG. 8(a), it is connected to a convex connector 91B provided on the other end surface of the straight part 91 with terminals and a 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 surface of the upper part 101 is connected to the concave connector 93A provided on the back surface of one end side of the straight part 93. Subsequently, the convex connector 93B provided on the other end surface of the straight 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 straight part 94 is connected to the convex connector 104B provided on the right end surface of the lower part 104, and the other end side of the straight part 94 is further connected to the left end side of the upper part 102. Next, one end side of the straight part 95 is connected to the right end side of the upper part 102, the other end side of the straight 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 straight part 96. Subsequently, the other end side of the straight 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 straight part 92 with terminals. 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 larger 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, 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, so 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 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 order to form 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, the coil 110 has a gap formed between each of the parts U, B, 22, 24 with the same size as the above-described gap t (see FIG. 3). By electrically connecting in a state where gaps are provided between each of the parts U, B, 22, 24, the coverlay 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 dielectric constant of the coverlay 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 there is no gap and they are in close contact between each of the parts U, B, 22, 24, the coverlay 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 contrary, by providing a gap without bringing each of the parts U, B, 22, 24 into close contact as in the coil 110 according to the simulation model, it is possible to suppress the coverlay 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, the electromagnetic field analysis simulation of coil 110 and 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 coil 200 according to Comparative Example 1, and FIG. 10(b) is a view showing the developed state of 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 arranged on the front surface side is shown by a solid line, and the copper foil portion arranged on the back surface side is shown by a broken line.

[0068] As shown in FIGS. 10(a) and 10(b), coil 200 is configured by laminating first film LY1 to 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, mainly 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 arranged 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 arranged 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 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 is in contact with the front surface side of the second film LY2, the back surface side of the second film LY2 is in contact with the back surface side of the third film LY3, and the front surface side of the third film LY3 is in contact with the front surface side of the fourth film LY4. 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. Further, 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 having 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 be mainly described with respect to the first film LM1, the even-numbered layers will be mainly described with respect to the second film LM2, and the description of the other films LM3 to LM15 will be omitted as appropriate. Further, when there is no need for particular distinction with respect to each of the films LM1 to LM15, 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 need to particularly distinguish, 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 in contact with each other, and they are folded in order so that the substrates J are sandwiched between the copper foils E of each film LM. As a result, they are laminated in a state where the substrates J are sandwiched between the copper foils E of each film LM, 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 supply of 13.56 MHz is applied, the inductance value of the coil 110 according to the present 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 equivalent inductance values of approximately 2 μH.

[0078] Also, as shown in FIG. 13, for the coil 200, when a high-frequency alternating current power supply with a frequency higher than about 15 MHz is applied, the inductance value increases rapidly. For the coil 300, when a high-frequency alternating current power supply with a frequency higher than about 30 MHz is applied, the inductance value increases rapidly. In contrast, it can be seen that the inductance value of the coil 110 remains 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 supply, it is preferable for circuit design that the inductance value has flat characteristics without significant fluctuations in the vicinity of 13.56 MHz, which is the power supply frequency of the high-frequency alternating current power supply. For this reason, it can be said that the coil 110, whose inductance value remains 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 supply. 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 as a solid line, the curve of the calculated value of the coil 200 is shown as a dashed line, and the calculated value of the coil 300 is shown as a dotted 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. A larger Q value means less transmission loss in wireless power transmission.

[0081] As shown in FIGS. 12 and 14, when a 13.56 MHz high-frequency AC 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 AC voltage is applied. As shown in FIG. 15, inductance 400L is the inductance of the inductor, resistance 400R is the DC resistance in the inductor 400, and inter-winding capacitance 400C is the inter-winding capacitance due to the (winding) structure of the inductor 400. When the inductance 400L is denoted as L and the inter-winding capacitance 400C is denoted as C, the following relationship shown in (Equation 1) holds with respect to the self-resonant frequency f.

Equation

[0084] Also, the above-described inter-winding capacitance 400C has a large individual difference in each inductor, and the performance variation in the manufacturing process is also likely to be large. Furthermore, in the vicinity of the self-resonant frequency in each inductor, the apparent variation of the inductance value with respect to the frequency becomes large, making it 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), i.e., 67.8 MHz or more in this embodiment.

[0086] Regarding this point, according to the above electromagnetic field analysis simulation, it has been shown that the self-resonant frequency of the coil 110 is more than five times 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 gist 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 connectors (connection parts) 24B, 32A, 34A, 36B, 62B, 63A, 64A, 65A, 66A 67A, 82B, 83A, 84A, 85A, 86A, 87B, 93A 101A, 104A Concave connectors (connection parts) 63, 64, 65, 66, 67, 83, 84, 93, 94, 95, 96 Straight parts (coil parts, film body) L1, M4 Base materials (insulating films) L2, M3, M5 Copper foils (conductive films) L3, M2, M6 Adhesive layers L4, M1, M7 Coverlay films (insulating films) 400 Inductor 400C Inter-winding capacitance 400L Inductance 400R Resistance t Gap

Claims

1. A first coil component comprising a first film body formed by sandwiching a first conductive thin film between first insulating thin films and a first connector attached to the first film body, a second coil component comprising a second film body formed by sandwiching a second conductive thin film between second insulating thin films and a second connector attached to the second film body and detachably provided with the first connector, and including when the first coil component and the second coil component are connected via the first connector and the second connector, a gap is formed between the first film body and the second film body, a coil.

2. The first film body and the second film body have flexibility, The coil according to Claim 1.

3. The first connector and the second connector are respectively disposed on the mutually facing surfaces of the first film body and the second film body, The coil according to Claim 1.

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

Images