Coil and electromagnetic induction heating device equipped with same

Abstract

To reduce the number of vias or through-holes and restrain an increase in AC resistance and an increase in cost.SOLUTION: A coil pattern 11 and a coil pattern 12 arranged on both sides of a substrate 10 are electrically connected to each other through through-holes TH. The coil pattern 11 and the coil pattern 12 each include an inner coil turn (first coil turn 110), an outer coil turn (sixth coil turn 160), and an intermediate coil turn (third coil turn 130), and includes a conductor pattern. The conductor pattern provided in the coil pattern 11 transitions from the radially inner side to the radially outer side at a predetermined twist pitch, and is connected to the conductor pattern provided in the coil pattern 12 through the through-holes TH after the transition. The twist pitch of the conductor pattern of the intermediate coil turns is set to be larger than the twist pitches of the conductor patterns of the inner and outer coil turns.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coil having a coil pattern made of a planar conductor formed on a substrate, and an electromagnetic induction heating device including the coil. [Background technology]

[0002] Inverter-type IH cooking heaters (hereinafter also referred to as "electromagnetic induction heating devices") are becoming widely used as devices that heat objects such as pots and pans without using fire to cook food. IH cooking heaters run high-frequency current through a heating coil placed directly under a glass top plate, generating eddy currents in a metal pot placed on the top plate, which generates heat through the electrical resistance of the pot itself. In this way, IH cooking heaters are rapidly becoming more and more popular, replacing gas ranges, because they allow cooking without using fire and are safer and provide a more comfortable cooking environment.

[0003] In an IH cooking heater, a high-frequency current of several tens of kHz is supplied from the inverter to the heating coil, which causes high-frequency AC losses due to the skin effect and proximity effect caused by the influence of high-frequency magnetic fields. The heating coil is made of a conductor wound in a spiral shape, and the coils located on the inner and outer circumferences are strongly affected by the magnetic field. For this reason, in order to suppress high-frequency AC losses, litz wire, which is made by twisting multiple insulated wires, is used for the conductor that forms the heating coil. However, coils using litz wire require multiple manufacturing processes such as twisting, winding, and terminal processing, which makes it difficult to control variations in electrical characteristics during mass production.

[0004] A method of forming a coil pattern on a printed circuit board has been proposed as a means of suppressing the variation in the electrical characteristics of magnetic components such as coils. By using a printed circuit board, it is possible to reduce the variation in electrical characteristics because manufacturing processes such as twisting are unnecessary. However, when a spiral coil is formed using a simple planar conductor pattern, there is an issue that the loss of the conductor pattern located on the inner and outer circumference sides where the magnetic field is concentrated becomes large.

[0005] As a means for solving this problem, for example, there is a technique described in Patent Document 1.

[0006] In Patent Document 1, a conductor pattern is formed by connecting multiple planar conductors arranged on multiple layers through vias or through holes, and a spiral coil is formed using the multiple conductor patterns. With this configuration, even when using a flat conductor pattern on a printed circuit board, it is possible to realize a twisted structure like a Litz wire, and high-frequency AC loss caused by a high-frequency magnetic field is reduced. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US Patent Application Publication No. 2009 / 0085706 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the technology described in Patent Document 1 requires a large number of vias or through holes to connect planar conductors arranged on multiple layers. Generally, vias or through holes increase the current density, which causes an increase in AC resistance.

[0009] Furthermore, since the implementation of vias or through holes requires the steps of drilling and plating, there is an issue that the number of vias or through holes increases, leading to increased costs due to the number of manufacturing steps.

[0010] An object of the present invention is to solve the above problems, to reduce the number of vias or through holes, and to suppress increases in AC resistance and costs, and to provide an electromagnetic induction heating device using the same. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a coil comprising a first coil pattern arranged in a spiral shape on one surface of a substrate, and a second coil pattern arranged in a spiral shape on the other surface of the substrate, the first coil pattern and the second coil pattern being electrically connected via a through hole or a via, the first coil pattern and the second coil pattern each comprising a plurality of wound coil turns, the plurality of coil turns comprising an inner circumferential side coil turn located on the inner circumferential side of the first coil pattern and the second coil pattern, an outer circumferential side coil turn located on the outer circumferential side of the first coil pattern and the second coil pattern, and an intermediate coil turn located between the inner circumferential side coil turn and the outer circumferential side coil turn, the inner circumferential side coil turn, and the intermediate coil turn each comprising a plurality of conductor patterns divided in a radial direction of the coil, the conductor pattern of the first coil pattern being a predetermined transition angle and after transitioning to the outside or inside, the conductor pattern of the intermediate coil turn is connected to the conductor pattern of the second coil pattern through the through hole or the via. transition angle is a conductor pattern of the inner coil turn and the outer coil turn transition angle It is characterized in that it is larger than Effect of the Invention

[0012] According to the present invention, it is possible to provide a coil in which the number of vias or through holes is reduced and an increase in AC resistance and an increase in costs are suppressed, and an electromagnetic induction heating device using the coil. [Brief description of the drawings]

[0013] [Figure 1] 1 is a plan view of a coil pattern 11 according to a first embodiment of the present invention, as viewed from above. [Diagram 2] 1 is a plan view of the coil pattern 12 seen from above with the coil pattern 11 and the substrate 10 removed. [Diagram 3]3 is a cross-sectional view showing the first turn from the inner periphery side along the line AA' to HH' shown in FIGS. 1 and 2. FIG. [Figure 4] 3 is a cross-sectional view showing the third turn from the inner periphery side along the line AA' to HH' shown in FIGS. 1 and 2. FIG. [Diagram 5] 3 is a cross-sectional view showing the fourth turn from the inner periphery side along the line AA' to HH' shown in FIGS. 1 and 2. FIG. [Figure 6] FIG. 11 is a plan view of a coil pattern 21 according to a comparative example, viewed from above. [Figure 7] FIG. 2 is a plan view of the coil pattern 22 viewed from above with the coil pattern 21 and the substrate removed. [Figure 8] FIG. 13 is a diagram showing the effect of reducing the number of through holes in the coil, comparing a comparative example with Example 1. [Figure 9] FIG. 11 is a plan view of a coil pattern 31 according to a second embodiment of the present invention, as viewed from above. [Figure 10] 1 is a plan view of the coil pattern 32 seen from above with the coil pattern 31 and the substrate 10 removed. [Figure 11] 11 is a cross-sectional view of the third coil turn 130 taken along lines AA' to HH' shown in FIGS. [Figure 12] FIG. 13 is a diagram showing the effect of reducing the number of through holes in the coil, comparing a comparative example with Example 2. [Figure 13] FIG. 11 is a plan view of a coil pattern 41 according to a third embodiment of the present invention, as viewed from above. [Figure 14] 1 is a plan view of the coil pattern 42 seen from above with the coil pattern 41 and the substrate 10 removed. [Figure 15] FIG. 13 is a diagram showing the effect of reducing the number of through holes in the coil, comparing a comparative example with Example 3. [Figure 16] FIG. 11 is a plan view of a coil pattern 51 according to a fourth embodiment of the present invention, as viewed from above. [Figure 17] 1 is a plan view of the coil pattern 52 seen from above with the coil pattern 51 and the substrate 10 removed. [Figure 18]FIG. 13 is a diagram showing the effect of reducing the number of through holes in the coil, comparing a comparative example with Example 4. [Figure 19] FIG. 11 is a schematic configuration diagram of an IH cooking heater according to a fifth embodiment of the present invention, cut in a vertical direction. [Figure 20] 20 is a top view showing a state in which top plate 7 and pot 8 have been removed from FIG. 19. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Like elements are given like reference numerals and similar descriptions will not be repeated.

[0015] The various components of the present invention do not necessarily have to be independent entities, and it is permitted that one component is made up of multiple members, that multiple components are made up of one member, that one component is part of another component, or that part of one component overlaps with part of another component. EXAMPLES

[0016] A first embodiment of the present invention will be described with reference to Figs. 1 to 7. Fig. 1 is a plan view of a coil pattern 11 according to the first embodiment of the present invention as viewed from above. Fig. 2 is a plan view of a coil pattern 12 as viewed from above with the coil pattern 11 and the substrate 10 removed. Fig. 3 is a cross-sectional view showing the first turn from the inner circumference side along lines A-A' to H-H' shown in Figs. 1 and 2. Fig. 4 is a cross-sectional view showing the third turn from the inner circumference side along lines A-A' to H-H' shown in Figs. 1 and 2. Fig. 5 is a cross-sectional view showing the fourth turn from the inner circumference side along lines A-A' to H-H' shown in Figs. 1 and 2.

[0017] As shown in Figs. 3 to 5, the coil 1 of the first embodiment has a first layer coil pattern 11 (first coil pattern) and a second layer coil pattern 12 (second coil pattern) formed on both surfaces of a substrate 10. That is, the coil pattern 11 is arranged on one surface (upper) of the substrate, and the coil pattern 12 is arranged on the other surface (lower) of the substrate. The substrate 10 is made of a material such as paper or glass cloth impregnated with phenol resin, epoxy resin, or the like. The coil pattern 11 and the coil pattern 12 are electrically connected via through holes or vias described later to form the coil 1.

[0018] As shown in Fig. 1 and Fig. 2, the coil 1 is composed of coil patterns 11 and 12 wound in a spiral shape over a plurality of turns. The coil 1 is composed of six coil turns, including a first coil turn 110 to a sixth coil turn 160, in which the first coil turn 110 constitutes the innermost coil turn and the sixth coil turn 160 constitutes the outermost coil turn. The first coil turn 110 and the second coil turn 120 constitute the inner coil turn, the fifth coil turn 150 and the sixth coil turn 160 constitute the outer coil turn, and the third coil turn 130 and the fourth coil turn 140 located between the inner coil turn and the outer coil turn constitute the intermediate coil turn. In other words, the intermediate coil turn is located between the inner coil turn and the outer coil turn.

[0019] As shown in Figures 3 and 4, the first coil turn 110 to the sixth coil turn 160 are composed of five divided conductor patterns 111 to 115. The conductor patterns 111 to 115 are formed by connecting a plurality of planar conductors, which are divided and arranged on a plurality of layers across the substrate 10, using through holes (for example, through holes TH11, TH12, TH31, TH41 shown in Figures 1 and 2).

[0020] The end of the coil pattern is connected to an external circuit after all the conductor patterns located on the first and second layers are connected by plane patterns 211 and 221. The thickness of the conductor pattern is preferably equal to or less than the skin depth determined by the frequency of the current supplied to the coil. The skin depth d can be expressed by the following formula.

[0021] d=√(2ρ / ωμ) In the above formula, ρ is the electrical resistivity, ω is the angular frequency of the current flowing through the coil, and μ is the absolute permeability of the conductor pattern. Each frequency ω is expressed as 2πf, where f is the frequency of the current flowing through the coil.

[0022] According to the above formula, for example, when copper is used as the material of the conductor pattern, the skin depth at a current frequency of 20 kHz is approximately 0.46 mm, so the thickness of the conductor pattern is preferably 0.4 mm, which is less than the skin depth.

[0023] Next, the transition of the conductor patterns constituting the first coil turn 110 will be explained with reference to Fig. 3, focusing on the conductor pattern 111. Here, the positions of the conductor patterns 111-115 constituting the first coil turn 110 are defined as lane 1, lane 2, and lane 3 from the innermost side to the outermost side of the first layer of the substrate 10, and as lane 4, lane 5, and lane 6 from the outermost side to the innermost side of the second layer of the substrate 10. States 11-18 indicate the states of the first coil turn 110 corresponding to the positions of lines A-A' to H-H' shown in Figs. 1 and 2.

[0024] <State11~State13> In State 11, the conductor pattern 111 starts from lane 1, which is located on the innermost side of the first layer, and transitions from lane to lane toward the outer periphery at a predetermined transition angle θ. Here, the predetermined transition angle θ is defined as the twist pitch. When the conductor pattern 111 reaches lane 2, it transitions to State 12 (line B-B'), when it reaches lane 3, it transitions to State 13 (line C-C'), and at line D-D', it transitions to State 14.

[0025] At this time, the predetermined angle θ is determined with reference to formulas 1 and 2. N1 in formula 1 means the maximum value of the conductor pattern located on the first or second layer, and is calculated using formula 2. Additionally, Np in formula 1 indicates the number of twists in one coil turn. Nstd in formula 2 indicates the number of conductor patterns that make up the coil pattern, and NLayer indicates the number of layers of the flat conductor, and N1 calculated using formula 2 is a natural number of 1 or more with the decimal point rounded up.

[0026] θ=180 / N1 / Np...Formula 1 N1=Nstd / NLayer...Formula 2 In coil 1 of Example 1, the transition angle θ of the first coil turn 110 can be calculated as θ=60 degrees using Equations 1 and 2, where Nstd=5, Np=1, and NLayer=2.

[0027] <state14> Conductive pattern 111 is located in lane 3 located on the outermost side of the first layer, and is connected from the first layer to lane 4 located in the second layer via through hole TH11. That is, conductive pattern 111 provided in coil pattern 11 transitions from the radial inside to the outside at a predetermined twist pitch, and after transitioning to the outside, is connected to conductive pattern 111 provided in coil pattern 12 via a through hole or a via.

[0028] <State15~State17> In State 15, the conductive pattern 111 starts from lane 4 of the second layer and transitions sequentially through lanes toward the inner periphery at predetermined transition angles θ, similar to States 11 to 13. When the conductive pattern 111 reaches lane 6, it transitions to State 18.

[0029] <state18> Conductive pattern 111 is located in lane 6, which is located on the innermost periphery of the second layer, and is connected to lane 1, which is located on the innermost periphery of the first layer, by a through hole TH12. It is also connected to conductive pattern 111 of second coil turn 120 (see FIG. 1) arranged on the first layer.

[0030] In this way, in the coil 1 described in this embodiment, the conductor patterns arranged in a plurality of layers are connected by through holes to form a twisted wire structure on a printed circuit board. Also, in the coil 1 of the first embodiment, the positions of the conductor patterns 111-115 in the first coil turn 110 are shifted during one turn to return to the original lane, which means that one twist is formed during one turn.

[0031] Next, the transition of the conductor patterns constituting the third coil turn 130 and the fourth coil turn 140 will be described with reference to FIGS. 4 and 5, focusing on the conductor pattern 111. FIG.

[0032] <State31~State37> In State 31, the conductor pattern 111 starts from lane 1, which is the innermost side of the first layer, and transitions toward the outer periphery at a predetermined transition angle θ. The conductor pattern 111 transitions to lane 2 between line B-B' and line C-C', transitioning to State 33, and then transitions to lane 3 between line E-E' and line F-F', transitioning to State 36. After transitioning to lane 3, it transitions to States 37 and 38. In States 31 to 32, States 33 to 35, and States 36 to 38, no lane transition occurs in the conductor pattern 111, but lane transitions occur in the other conductor patterns.

[0033] In the coil 1 of Example 1, the transition angle θ of the third coil turn 130 can be calculated as θ=120 degrees using the above-mentioned formulas 1 and 2, where Nstd=5, Np=0.5, and NLayer=2.

[0034] <state38> Conductive pattern 111 is located in lane 3, which is the outermost periphery of the first layer, and is connected to lane 4, which is the outermost periphery of the second layer, by through-hole TH31.

[0035] <State41~State47> 5, the conductive pattern 111 is located in lane 4, which is the outermost side of the second layer, and transitions from lane 4 to the inner side at a predetermined transition angle θ. When the conductive pattern 111 reaches lane 6, it transitions to State 48.

[0036] <state48> The conductor pattern 111 is located in lane 6 on the innermost periphery of the second layer, and is connected via a through hole TH41 to lane 1 of the fifth coil turn 150 located on the innermost periphery of the first layer.

[0037] In this manner, in the coil 1 of Example 1, the third coil turn 130 and the fourth coil turn 140 are configured so that the positions of the conductor patterns 111-115 are shifted over two turns to return to the original lane, which means that one twist is formed over two turns.

[0038] As described above, in the coil 1 of the first embodiment, the twist pitch is changed depending on the radial position of the coil pattern. Specifically, the twist pitch of the two turns (the first coil turn 110, the second coil turn 120, the fifth coil turn 150, and the sixth coil turn 160) located on the inner circumference side and the outer circumference side is set to 60 degrees, and one twist is formed in one turn, whereas the twist pitch of the two turns (the third coil turn 130 and the fourth coil turn 140) located in the middle is set to 120 degrees, and one twist is formed in two turns. In other words, the twist pitch of the conductor pattern of the middle coil turn (the third coil turn 130 and the fourth coil turn 140) is twice the twist pitch of the conductor pattern of the inner circumference side coil turn (the first coil turn 110 and the second coil turn 120) and the outer circumference side coil turn (the fifth coil turn 150 and the sixth coil turn 160). The twist pitch of the conductor patterns of the inner coil turns (first coil turn 110, second coil turn 120) and the outer coil turns (fifth coil turn 150, sixth coil turn 160) are set to be equal.

[0039] In the coil 1 of the first embodiment, the twist pitch of the coil turns located on the inner and outer periphery sides where the magnetic flux density penetrating the coil is high is made dense, and the twist pitch of the coil turns located in the middle where the magnetic flux density penetrating the coil is low is made sparse. In other words, the twist pitch of the conductor pattern of the middle coil turn (third coil turn 130, fourth coil turn 140) is made larger than the twist pitch of the conductor pattern of the inner coil turn (first coil turn 110, second coil turn 120) and the outer coil turn (fifth coil turn 150, sixth coil turn 160). In the first embodiment, by configuring as described above, it is possible to reduce the number of through holes or vias while suppressing an increase in high frequency loss caused by a high frequency magnetic field.

[0040] Next, the configuration of the coil 2 of the comparative example to be compared will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a plan view of the coil pattern 21 according to the comparative example, as viewed from above. Fig. 7 is a plan view of the coil pattern 22, as viewed from above, with the coil pattern 21 and the substrate removed. Descriptions of parts that overlap with the description of the coil 1 described above will be omitted.

[0041] The coil 2, like the coil 1, is composed of coil patterns 21 and 22 wound in a spiral shape over a plurality of turns. The coil 2 is composed of six coil turns, including a first coil turn 110 to a sixth coil turn 160, with the first coil turn 110 constituting the innermost coil turn and the sixth coil turn 160 constituting the outermost coil turn. The first coil turn 110 and the second coil turn 120 constitute the inner coil turn, the fifth coil turn 150 and the sixth coil turn 160 constitute the outer coil turn, and the third coil turn 130 and the fourth coil turn 140, which are located between the inner coil turn and the outer coil turn, constitute the intermediate coil turn. In other words, the intermediate coil turn is located between the inner coil turn and the outer coil turn.

[0042] The first coil turn 110 to the sixth coil turn 160 are composed of five divided conductor patterns 111 to 115. The conductor patterns 111 to 115 are formed by connecting multiple planar conductors, which are divided and arranged on multiple layers across a substrate, using through holes (e.g., TH11, TH12). In the coil 2, the twist pitch is fixed in all turns, and one twist is formed per coil turn.

[0043] 8 is a diagram showing the effect of reducing the number of through holes in the coil, comparing the comparative example with example 1. The comparative example shown in FIG. 8 shows an example of the coil 2 in FIGS.

[0044] 8, the number of through holes in the structure of the comparative example is 59. In contrast, the number of through holes in the structure of Example 1 is 49. That is, in the structure of Example 1, the number of through holes can be reduced by about 17% compared to the comparative example.

[0045] In this way, in the coil described in the first embodiment, it is possible to reduce the number of through holes by changing the twist pitch of the conductor pattern depending on the radial position of the coil pattern.

[0046] In the first embodiment, the coil turns located on the inner circumference side and the outer circumference side (first coil turn 110, second coil turn 120, fifth coil turn 150, sixth coil turn 160) are twisted once per turn, and the two coil turns located in the middle (third coil turn 130, fourth coil turn 140) are twisted once. However, the two coil turns on the inner circumference side (first coil turn 110, second coil turn 120) and the one coil turn on the outer circumference side (sixth coil turn 160) may be twisted once in one turn, and the remaining three coil turns (third coil turn 130, fourth coil turn 140, fifth coil turn 150) may be twisted once.

[0047] Furthermore, in the first embodiment, the twist pitch is constant in the third coil turn 130 and the fourth coil turn 140, but the twist pitch may be varied depending on the circumferential position. For example, by varying the twist pitch so that the wire lengths of the conductor patterns 111 to 115 located in the inner and outer lanes are equal, it is expected that the effect of suppressing the current imbalance caused by the impedance difference of the conductor patterns and reducing the bias of loss can be expected.

[0048] In the first embodiment, the conductor turns of the coil pattern 11 transition from the radially inner side to the radially outer side at a predetermined twist pitch, and the conductor pattern of the coil pattern 12 transitions from the radially outer side to the radially inner side at a predetermined twist pitch. However, the conductor turns of the coil pattern 11 may transition from the radially outer side to the radially inner side at a predetermined twist pitch, and the conductor pattern of the coil pattern 12 may transition from the radially inner side to the radially outer side at a predetermined twist pitch. EXAMPLES

[0049] Example 2 of the present invention will be described with reference to Figures 9 to 12. Figure 9 is a plan view of coil pattern 31 according to Example 2 of the present invention as viewed from above. Figure 10 is a plan view of coil pattern 32 as viewed from above with coil pattern 31 and substrate 10 removed. Figure 11 is a cross-sectional view of third coil turn 130 taken along lines A-A' to H-H' shown in Figures 9 and 10.

[0050] The coil 3 of the second embodiment is configured by a coil pattern 31 (first coil pattern) and a coil pattern 32 (second coil pattern) wound in a spiral shape over a plurality of turns, similarly to the coil 1 described in the first embodiment. The coil 3 is configured by six coil turns consisting of a first coil turn 110 to a sixth coil turn 160, the first coil turn 110 constitutes the innermost coil turn, and the sixth coil turn 160 constitutes the outermost coil turn. The first coil turn 110 and the second coil turn 120 constitute the inner coil turn, the fifth coil turn 150 and the sixth coil turn 160 constitute the outer coil turn, and the third coil turn 130 and the fourth coil turn 140 located between the inner coil turn and the outer coil turn constitute the intermediate coil turn. In other words, the intermediate coil turn is located between the inner coil turn and the outer coil turn.

[0051] The difference from the coil 1 of the first embodiment is that the number of conductor patterns forming each coil turn is configured to be different depending on the radial position of the coil pattern. Specifically, the first coil turn 110 and the second coil turn 120 on the inner circumference side where the magnetic field is concentrated and the fifth coil turn 150 and the sixth coil turn 160 on the outer circumference side are configured with five conductor patterns (for example, the first coil turn 110 is the conductor patterns 111 to 115), whereas the third coil turn 130 and the fourth coil turn 140 where the magnetic field concentration is suppressed compared to the inner circumference side and the outer circumference side are configured with three conductor patterns (for example, the third coil turn 130 is the conductor patterns 131 to 133). In other words, the number of conductor patterns of the inner circumference side coil turn (the first coil turn 110, the second coil turn 120) and the outer circumference side coil turn (the fifth coil turn 150, the sixth coil turn 160) is made larger than the number of conductor patterns of the intermediate coil pattern (the third coil turn 130, the fourth coil turn 140).

[0052] In this embodiment, in order to make the total cross-sectional area of ​​the conductor patterns constituting each coil turn equal, the width of the conductor patterns constituting the third coil turn 130 and the fourth coil turn 140 is made wider than the width of the conductor patterns constituting the first coil turn 110, the second coil turn 120, the fifth coil turn 150, and the sixth coil turn 160. In other words, the width of the conductor pattern of the intermediate coil pattern (the third coil turn 130, the fourth coil turn 140) is made wider than the width of the conductor pattern of the inner coil turn (the first coil turn 110, the second coil turn 120) and the outer coil turn (the fifth coil turn 150, the sixth coil turn 160).

[0053] The second coil turn 120 and the third coil turn 130 are connected via a planar pattern 231 (connection pattern) that connects together the ends of the conductor patterns that make up each coil turn, and the fourth coil turn 140 and the fifth coil turn 150 are connected via a planar pattern 232 (connection pattern) that connects together the ends of the conductor patterns that make up each coil turn. In other words, the inner coil turn (second coil turn 120) and the middle coil turn (third coil turn 130) are connected via the connection pattern (planar pattern 231), and the outer coil turn (fifth coil turn 150) and the middle coil turn (fourth coil turn 140) are connected via the connection pattern (planar pattern 232). The transitions of the conductor patterns constituting the first coil turn 110, the second coil turn 120, the fifth coil turn 150, and the sixth coil turn 160 are similar to those of coil 1 in Example 1, so a detailed explanation will be omitted. Instead, the transition of the conductor patterns constituting the third coil turn 130 will be explained with reference to Fig. 11, focusing on conductor pattern 131. Here, the positions of the conductor patterns 131-133 constituting the third coil turn 130 are defined as lane 1 and lane 2 from the innermost side to the outermost side of the first layer of substrate 10, and as lane 3 and lane 4 from the outermost side to the innermost side of the second layer of substrate 10.

[0054] 11 indicate the states of the third coil turn 130 at the positions of lines AA' to HH' shown in FIGS.

[0055] <State31~State33> In State 31, the conductor pattern 131 starts from lane 1, which is the innermost periphery of the first layer, and transitions toward the outer periphery at a predetermined transition angle θ. When the conductor pattern 131 reaches lane 2, it transitions to State 32 (line B-B'), and then to State 33 (line C-C'). When lane 3 of the second layer becomes empty, it transitions to State 34 (line D-D'). Note that in the coil 3 of the second embodiment, the transition angle θ of the third coil turn 130 can be calculated as θ=90 degrees using Equations 1 and 2, since Nstd=3, Np=1, and NLayer=2.

[0056] <state34> Conductive pattern 131 is located in lane 2, which is the outermost periphery of the first layer, and is connected to lane 3, which is the outermost periphery of the second layer, by through-hole TH31.

[0057] <State35~State37> Conductive pattern 131 starts from lane 3, which is the outermost side of the second layer, and transitions toward the inner periphery at a predetermined transition angle θ, such as State 35 (line E-E') to State 37 (line G-G'). When conductive pattern 131 reaches lane 4 and lane 1 of the first layer becomes empty, it transitions to State 38 (line H-H').

[0058] <state38> Conductive pattern 131 is located in lane 4, which is the innermost periphery of the second layer, and is connected to lane 1 of the fourth coil turn, which is located on the innermost periphery of the first layer, by a through hole TH32.

[0059] In this way, in the third coil turn 130, the positions of the three conductor patterns are shifted according to the circumferential position to form a twisted structure.

[0060] Fig. 12 is a diagram showing the effect of reducing the number of through holes in the coil, comparing the comparative example with example 2. The comparative example in Fig. 12 shows the coil 2 described in example 1 (Figs. 6 and 7).

[0061] 12, the number of through holes in the structure of the comparative example is 59. In contrast, the number of through holes in the structure of Example 2 is 51. That is, in the structure of Example 2, the number of through holes can be reduced by about 13% compared to the comparative example.

[0062] As described above, in the coil 3 described in Example 2, by changing the number of conductor patterns depending on the radial position of the coil pattern, it is possible to reduce the number of through holes compared to coil 2 (comparative example), as in Example 1. EXAMPLES

[0063] Example 3 of the present invention will be described with reference to Figs. 13 to 15. Fig. 13 is a plan view of a coil pattern 41 according to Example 3 of the present invention as viewed from above. Fig. 14 is a plan view of a coil pattern 42 as viewed from above with the coil pattern 41 and the substrate 10 removed. Fig. 15 is a diagram showing the effect of reducing the number of through holes in the coil, comparing a comparative example with Example 3. In Example 3, descriptions of contents that overlap with the above-mentioned Examples 1 and 2 will be omitted, and only the differences will be described.

[0064] The coil 4 described in the third embodiment is configured by a coil pattern 41 (first coil pattern) and a coil pattern 42 (second coil pattern) wound in a spiral shape over a plurality of turns, similarly to the coil 1 of the first embodiment. The coil 4 is configured by six coil turns consisting of a first coil turn 110 to a sixth coil turn 160, the first coil turn 110 constitutes the innermost coil turn, and the sixth coil turn 160 constitutes the outermost coil turn. The first coil turn 110 and the second coil turn 120 constitute the inner coil turn, the fifth coil turn 150 and the sixth coil turn 160 constitute the outer coil turn, and the third coil turn 130 and the fourth coil turn 140 located between the inner coil turn and the outer coil turn constitute the intermediate coil turn. In other words, the intermediate coil turn is located between the inner coil turn and the outer coil turn.

[0065] Similarly to the coil 3 of Example 2, the coil 4 is configured such that the number of conductor patterns forming each coil turn varies depending on the radial position of the coil pattern. Specifically, the first coil turn 110 and the second coil turn 120 on the inner circumference side where the magnetic field is concentrated and the fifth coil turn 150 and the sixth coil turn 160 on the outer circumference side are configured with five conductor patterns (for example, the first coil turn 110 is configured with conductor patterns 111-115), whereas the third coil turn 130 and the fourth coil turn 140, where the magnetic field concentration is suppressed compared to the inner circumference side and the outer circumference side, are configured with three conductor patterns (for example, the third coil turn 130 is configured with conductor patterns 131-133).

[0066] The difference from Example 2 is that the twist pitch (transition angle θ) of the conductor patterns 131-133 constituting the third coil turn 130 and the fourth coil turn 140 is sparse, and one twist is formed for two turns. In other words, the middle coil pattern (third coil turn 130, fourth coil turn 140) forms one twist across multiple turns.

[0067] In this way, in the coil 4 described in Example 3, the number of conductor patterns is variable depending on the radial position of the coil pattern, and further, the twist pitch in the turns composed of fewer conductor patterns is made sparser than the other turns.

[0068] 15, the number of through holes in the structure of the comparative example is 59. In contrast, the number of through holes in the structure of Example 3 is 45. That is, in the structure of Example 3, the number of through holes can be reduced by about 24% compared to the comparative example. EXAMPLES

[0069] Example 4 of the present invention will be described with reference to Figs. 16 to 18. Fig. 16 is a plan view of coil pattern 51 according to Example 4 of the present invention as viewed from above. Fig. 17 is a plan view of coil pattern 52 as viewed from above with coil pattern 51 and substrate 10 removed. Fig. 18 is a diagram showing the effect of reducing the number of through holes in the coil, comparing a comparative example with Example 4. Descriptions of contents that overlap with the above-mentioned Examples 1 to 3 will be omitted, and only the differences will be described.

[0070] The coil 5 of the fourth embodiment is composed of a coil pattern 51 (first coil pattern) and a coil pattern 52 (second coil pattern) wound in a spiral shape over a plurality of turns, as in the first embodiment. The coil 5 is composed of six coil turns, including a first coil turn 110 to a sixth coil turn 160, in which the first coil turn 110 constitutes the innermost coil turn, and the sixth coil turn 160 constitutes the outermost coil turn. The first coil turn 110 and the second coil turn 120 constitute the inner coil turn, the fifth coil turn 150 and the sixth coil turn 160 constitute the outer coil turn, and the third coil turn 130 and the fourth coil turn 140 located between the inner coil turn and the outer coil turn constitute the intermediate coil turn. In other words, the intermediate coil turn is located between the inner coil turn and the outer coil turn.

[0071] The first coil turn 110, the second coil turn 120, the fifth coil turn 150, and the sixth coil turn 160 are each composed of five divided conductor patterns 111 to 115. On the other hand, in the coil 5 of the fourth embodiment, the third coil turn 130 and the fourth coil turn 140 have a single wire flat plate structure composed of one conductor pattern 131, 132 in the first layer (one side of the substrate) and the second layer (the other side of the substrate), respectively, and no twisted structure is formed in the regions of the third coil turn 130 and the fourth coil turn 140. In other words, the middle coil turn (the third coil turn 130 and the fourth coil turn 140) is provided with one continuous conductor pattern, which is connected to the conductor pattern of the inner coil turn (the first coil turn 110 and the second coil turn 120) and the conductor pattern of the outer coil turn (the fifth coil turn 150 and the sixth coil turn 160). Moreover, one conductor pattern 131, 132 arranged on each of the first layer (one surface of the board) and the second layer (the other surface of the board) are connected in parallel via a through hole or a via.

[0072] As shown in Fig. 18, the number of through holes in the structure of the comparative example is 59. In contrast, the number of through holes in the structure of Example 4 is 40. That is, the number of through holes in the structure of Example 4 can be reduced by about 32% compared to the comparative example. In Example 4, the number of through holes can be further reduced compared to the coils of Examples 1 to 3. EXAMPLES

[0073] Example 5 will be described with reference to Figs. 19 and 20. In Example 5, the coil 1 of Example 1 is applied to a heating coil for an IH cooking heater, but the coils 2 to 5 of Examples 2 to 4 can also be applied. Fig. 19 is a schematic diagram showing the configuration of an IH cooking heater according to Example 5 of the present invention, cut in the vertical direction. Fig. 20 is a top view of Fig. 19 with the top plate 7 and pot 8 removed.

[0074] An IH cooking heater (electromagnetic induction heating device) has a top plate 7 on which a pot 8, which is a cooking utensil, is placed, and a coil 1 for heating the pot 8 is provided below the top plate. The coil 1 is placed on the upper surface of a ferrite core 500 which serves as a magnetic path for the magnetic flux generated from the coil 1. The pot 8 placed on the upper surface of the top plate 7 is induction heated by the magnetic flux generated from the coil 1. The coil 1 and the ferrite core 500 are supported by a support member 6. As shown in FIG. 20 , the ferrite core 500 is arranged radially from the center of the coil 1.

[0075] The ferrite core 500 is arranged so as to avoid the vias and through-holes TH of the coil 1, thereby suppressing the concentration of high-frequency magnetic fields at the vias and through-holes TH and reducing high-frequency AC losses.

[0076] The present invention is not limited to the above-mentioned embodiment, and various modifications are included. For example, the above-mentioned embodiment has been described in detail to easily explain the present invention, and is not necessarily limited to those including all of the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Also, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0077] 1, 2, 3, 4, 5... coil, 500... ferrite core, 6... support member, 7... top plate, 8... pot, 10... substrate, 211, 221, 221, 222... plane pattern, 11, 12, 21, 22, 31, 32, 41, 42... coil pattern, 110... first coil turn, 120... second coil turn, 130... third coil turn, 140... fourth coil turn, 150... fifth coil turn, 160... sixth coil turn, TH11, TH12, TH31, TH32, TH41... through hole, 111, 112, 113, 114, 115, 131, 132, 133, 134, 135... conductor pattern

Claims

1. A coil comprising a first coil pattern arranged in a spiral shape on one surface of a substrate and a second coil pattern arranged in a spiral shape on the other surface of the substrate, the first coil pattern and the second coil pattern being electrically connected via a through hole or a via, The first coil pattern and the second coil pattern each include a plurality of wound coil turns, the plurality of coil turns include an inner circumferential side coil turn located on the inner circumferential side of the first coil pattern and the second coil pattern, an outer circumferential side coil turn located on the outer circumferential side of the first coil pattern and the second coil pattern, and an intermediate coil turn located between the inner circumferential side coil turn and the outer circumferential side coil turn, and the inner circumferential side coil turn, the outer circumferential side coil turn, and the intermediate coil turn each include a plurality of conductor patterns divided in a radial direction of the coil, The conductor pattern provided in the first coil pattern transitions from the radially inner side to the radially outer side or from the radially outer side to the inner side at a predetermined transition angle, and after transitioning to the outer side or the inner side, is connected to the conductor pattern provided in the second coil pattern via the through hole or the via, A coil characterized in that a transition angle of the conductor pattern of the intermediate coil turn is larger than the transition angles of the conductor patterns of the inner coil turn and the outer coil turn.

2. In claim 1, A coil characterized in that a transition angle of the conductor pattern of the inner coil turn and a transition angle of the conductor pattern of the outer coil turn are equal.

3. In claim 2, A coil characterized in that a transition angle of the conductor pattern of the intermediate coil turn is twice the transition angle of the conductor patterns of the inner coil turn and the outer coil turn.

4. In claim 1, A coil characterized in that the number of conductor patterns of the inner coil turn is different from the number of conductor patterns of the intermediate coil turn.

5. In claim 4, A coil characterized in that the number of conductor patterns of the inner coil turn is greater than the number of conductor patterns of the intermediate coil turn.

6. In claim 4, A coil characterized in that the width of the conductor pattern of the intermediate coil turn is wider than the widths of the conductor patterns of the inner coil turn and the outer coil turn.

7. In claim 1, A coil characterized in that the intermediate coil turn is twisted once across multiple turns.

8. In claim 1, A coil comprising a connection pattern that connects the inner coil turn or the outer coil turn to the intermediate coil turn.

9. A coil comprising a first coil pattern arranged in a spiral shape on one surface of a substrate and a second coil pattern arranged in a spiral shape on the other surface of the substrate, the first coil pattern and the second coil pattern being electrically connected via a through hole or a via, The first coil pattern and the second coil pattern each include a plurality of wound coil turns, the plurality of coil turns include an inner circumferential side coil turn located on the inner circumferential side of the first coil pattern and the second coil pattern, an outer circumferential side coil turn located on the outer circumferential side of the first coil pattern and the second coil pattern, and an intermediate coil turn located between the inner circumferential side coil turn and the outer circumferential side coil turn, and the inner circumferential side coil turn and the outer circumferential side coil turn each include a plurality of conductor patterns divided in the radial direction of the coil, the conductor pattern of the inner circumferential coil turn and the conductor pattern of the outer circumferential coil turn of the first coil pattern transition from the radially inner side to the radially outer side or from the radially outer side to the inner side at a predetermined transition angle, and after transitioning to the outer side or the inner side, are connected to the conductor pattern of the second coil pattern via the through hole or the via, A coil, characterized in that the conductor pattern of the inner coil turn and the conductor pattern of the outer coil turn are connected to one conductor pattern of the middle coil turn.

10. In claim 9, The intermediate coil turn has one conductor pattern disposed on each of one surface of the substrate and the other surface of the substrate, A coil characterized in that one conductor pattern arranged on each of one surface of the substrate and the other surface of the substrate is connected in parallel via the through hole or via.

11. An electromagnetic induction heating device comprising a top plate on which a pot is placed and a coil positioned below the top plate for heating the pot, An electromagnetic induction heating device comprising the coil according to any one of claims 1 to 10.

12. 12. The rotor according to claim 11, further comprising a ferrite core supporting the coil. The electromagnetic induction heating device is characterized in that the ferrite core is disposed in an area where the through hole or the via is not formed.

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