Substrate coil and transformer

Abstract

To provide a technique for improving the performance of a tactile sensor sheet in which a plurality of tactile sensor chips are arranged on a flexible sheet.SOLUTION: A board coil (10) is formed by electrically connecting and laminating winding patterns (1a to 9a) provided on a plurality of layers (1 to 9) constituting a multilayer board at connection portions (1d to 8d, 2e to 9e) in the winding patterns (1a to 9a), and the connection portions (1d to 8d, 2e to 9e) in the winding patterns (1a to 9a) have an elongated shape extending in the circumferential direction of the winding pattern when viewed from the normal direction of the board coil (10), and are arranged on the outer peripheral portion of the winding patterns (1a to 9a).SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a substrate coil and a transformer formed by overlapping winding patterns on a substrate. [Background technology]

[0002] In recent years, there has been a demand for smaller and lower-cost power electronics equipment. Therefore, there is an urgent need to develop high-density mounting technology, small and low-profile magnetic component technology, and high-efficiency aperture technology for the components mounted in power electronics equipment. Regarding small and low-profile magnetic component technology, there is a shift from bulk-type components formed with wound coils to board-type components formed by overlapping winding patterns on a board.

[0003] For these board-type components, the connection of each layer of the PWB (Printed Wired Board) becomes an issue. That is, the location of the connection point for each layer must be changed when viewed from the normal direction of the board, which leads to an increase in the number of layers and size, and further increases the parasitic L and interlayer capacitance C, resulting in inconveniences such as the need for an external resonance L.

[0004] Furthermore, depending on the connection points of each layer of the PWB, the skin effect of the current passing through the patterns of each layer can cause uneven current density within the connection, resulting in current concentration and temperature rise in specific parts of the connection. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-077538 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-190934 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-324962 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a technology that enables the miniaturization and low profile of a substrate coil formed by stacking substrates on which winding patterns are provided, as well as reduces current concentration at specific connection points on each layer, thereby improving reliability. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a substrate coil formed by laminating winding patterns provided on a plurality of layers constituting a multilayer substrate and electrically connecting the winding patterns at connection portions of the winding patterns, the substrate coil comprising: The substrate coil is characterized in that the connection portion in the winding pattern has an elongated shape extending in the circumferential direction of the winding pattern when viewed from the normal direction of the substrate coil, and is arranged on the outer periphery of the winding pattern.

[0008] This allows the winding patterns on each substrate of the substrate coil to be connected at a connection portion located on the outer periphery of the winding pattern. Therefore, the connection portion can be positioned so as not to impede the flow of current through each winding pattern, improving the winding efficiency of the substrate coil. As a result, it is possible to achieve a smaller, thinner substrate coil. Here, the connection portion refers to a portion of the winding pattern on each substrate, where a connection means (described below) for connecting to the winding pattern above or below is located.

[0009] Here, due to the skin effect, high-frequency currents tend to pass through the inner periphery of each winding pattern. Therefore, if the connection portion has a large radial area of ​​the winding pattern, current will preferentially flow through the inner periphery, causing excessive current to flow in certain parts of the connection portion, potentially resulting in overheating and reduced reliability. In contrast, in the present invention, the connection portion has an elongated shape extending in the circumferential direction of the winding pattern and is located on the outer periphery of the winding pattern. This reduces the likelihood of non-uniform current density occurring within the connection portion, thereby improving the reliability of the substrate coil. Note that, in the above, the effect is enhanced when all of the connection portions have an elongated shape extending in the circumferential direction of the winding pattern and are located on the outer periphery of the winding pattern. However, the present invention also includes cases where some connection portions do not have an elongated shape extending in the circumferential direction of the winding pattern or where some connection portions are not located on the outer periphery of the winding pattern.

[0010] Furthermore, in the present invention, among the winding patterns provided on the plurality of layers, the connection portions of two winding patterns that are overlapped and connected to each other may be arranged at positions that overlap each other on the outer periphery of the winding patterns when viewed from the normal direction of the substrate coil, and the connection portions may be connected to each other by a connection means that extends in the normal direction of the substrate coil.

[0011] This makes it possible to connect each winding pattern simply by connecting each connection portion with a connecting means extending in the normal direction of the substrate coil, making it possible to form the substrate coil more easily.

[0012] Furthermore, in the present invention, the pairs of connection portions of the two winding patterns connected to each other and the pairs of connection portions of the two winding patterns connected next may be arranged so as to be consecutively aligned on the outer periphery of the winding patterns. This allows the connection portions for connecting to the previous winding pattern and the connection portions for connecting to the next winding pattern in each winding pattern to be arranged so as to be consecutively aligned on the outer periphery of the winding patterns. This reduces the distance between the ends of the windings in each winding pattern, thereby narrowing the gap between the ends. As a result, it is possible to improve the winding efficiency of each winding pattern as much as possible. Note that, in this case, the effect is enhanced when all the connection pairs are consecutively aligned on the outer periphery of the winding patterns. However, a case in which some connection pairs are not consecutively aligned on the outer periphery of the winding patterns is also included in the present invention.

[0013] In addition, in the present invention, the connection portions may be provided in portions protruding further outward from the outer periphery of the winding pattern, and the connection means may be through-holes penetrating multiple layers. This allows the winding patterns to be connected without affecting the current-passing areas of each winding pattern. This more reliably improves winding efficiency and enables the miniaturization and low-profile of the substrate coil. Furthermore, since the connection portions are connected using through-holes as the connection means, the substrates can be connected by forming through-holes penetrating the multilayer substrate after stacking the substrates, thereby improving the productivity of the substrate coil. Note that, even in this case, the effect is enhanced when all of the connection portions are provided in portions protruding further outward from the outer periphery of the winding pattern. However, the present invention also includes a case where some connection pairs are not provided in portions protruding further outward from the outer periphery of the winding pattern.

[0014] In addition, in the present invention, the connection means may be via holes that are arranged in one or two rows in the circumferential direction of the winding patterns on the connection portions of the two winding patterns that are connected to each other, and that are formed between the connection portions in the normal direction of the winding patterns. This makes it possible to more densely and efficiently arrange the via holes at the connection portions. As a result, the area of ​​the connection portions can be reduced, and the winding efficiency of the winding patterns can be more reliably improved. It is possible to improve

[0015] Furthermore, in the present invention, the connection means may be a conductive portion (e.g., conductive plating) applied to the side of the connection portion of the insulating layer formed between the two winding patterns to be connected to each other. This allows the area of ​​the connection portion as viewed from the normal direction of the winding patterns to be reduced as much as possible, improving winding efficiency and enabling a smaller, thinner substrate coil. It also reduces manufacturing costs, reduces parasitic L and C in the substrate coil, prevents malfunction of a device incorporating the substrate coil, and reduces noise. The conductive portion may be formed by plating, a conductive film formed by sputtering or the like, or by attaching metal foil.

[0016] The present invention may also include a magnetic core arranged to cover a portion of the winding pattern when viewed from the normal direction of the substrate coil, and the connection portion may be arranged in a portion not covered by the magnetic core when viewed from the normal direction of the substrate coil. Here, the magnetic core streamlines the flow of the magnetic field generated by the coil windings and increases the magnetic field. Meanwhile, the magnetic field generated by passing through the connection portion has a different direction from the magnetic field generated by the coil windings and may cause disturbance to the magnetic field generated by the coil windings. In contrast, in the present invention, the connection portion is arranged in a portion where the magnetic core is not provided in a plan view, thereby preventing the magnetic field passing through the connection portion from disturbing the flow of the magnetic field generated by the magnetic core. As a result, the flow of the magnetic field generated by the substrate coil windings can be more reliably streamlined and increased.

[0017] The present invention may also include a magnetic core consisting of two magnetic circuits arranged to cover a portion of the winding pattern in point symmetry with respect to the center of the winding pattern when viewed from the normal direction of the substrate coil, and the connection parts may be arranged symmetrically with respect to the portion covered by the two magnetic circuits when viewed from the normal direction of the substrate coil. In this way, even if a current flowing between the connection parts disturbs the flow of the magnetic field generated by the magnetic core, the disturbance occurs symmetrically with respect to the winding pattern, thereby preventing a biased effect on the flow of the magnetic field generated by the magnetic core. As a result, it is possible to stabilize the distribution of the magnetic field generated by the substrate coil.

[0018] The present invention also provides a transformer having a plurality of coils arranged so as to overlap each other, including a magnetic core, which inputs a current to one coil and outputs an induced current flowing through another coil, the magnetic core has a portion disposed to pass through the center of the plurality of coils; At least some of the coils may be the substrate coils described above, which may form a transformer (including a voltage transformer and an isolation transformer). In this case, the transformer can be made smaller and thinner, and the device in which the transformer is installed can be made smaller.

[0019] In this case, the magnetic core may have a path core structure in which a core is disposed between the coils of the plurality of coils. Also, the magnetic core may be a rod core having a rod-shaped core that passes through the center of the plurality of coils.

[0020] The above-described configurations and processes can be combined with each other to constitute the present invention as long as no technical contradiction occurs. [Effects of the Invention]

[0021] According to the present invention, in a substrate coil formed by stacking substrates on which winding patterns are provided, it is possible to make the coil smaller and thinner, and it is also possible to reduce current concentration at the connection parts of specific layers and improve reliability. This makes it possible to directly incorporate coils, inductances, transformers, etc. into electronic circuit boards, which in turn makes it possible to reduce the size of electronic devices, the number of mounted parts, and production costs. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a plan view of the substrate coil according to the first embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a transformer constructed using two coils including a substrate coil in an embodiment of the present invention. [Figure 3] FIG. 10 is a schematic diagram showing the connection state of the winding patterns from the first substrate to the ninth substrate. [Figure 4] FIG. 10 is a plan view for explaining the state of connection when the winding patterns of the first to ninth substrates are connected by a conventional method. [Figure 5] 10 is a schematic diagram showing a current flow when a high-frequency current is applied to a substrate coil. FIG. [Figure 6] 3A and 3B are schematic diagrams for explaining connection points in the winding patterns of the substrates and the state of connection by via holes in the first embodiment of the present invention. [Figure 7] 3 is a schematic diagram for explaining connection points in the winding patterns of each substrate and how current flows in the first embodiment of the present invention. FIG. [Figure 8] FIG. 2 is a perspective view of a substrate coil combined with a magnetic core according to the first embodiment of the present invention. [Figure 9] 1 is a plan view of a winding pattern on each substrate and a combination of a magnetic core with the winding of a substrate coil in Example 1 of the present invention. FIG. [Figure 10]FIG. 10 is a perspective view showing windings and connection points in a second embodiment of the present invention. [Figure 11] 10 is a plan view of the winding patterns on each substrate and the windings of the substrate coil combined with a magnetic core in Example 2 of the present invention. FIG. [Figure 12] 10A to 10C are diagrams illustrating a first aspect of a method for manufacturing a substrate coil according to a second embodiment of the present invention. [Figure 13] 10A to 10C are diagrams illustrating a second aspect of the method for manufacturing the substrate coil according to the second embodiment of the present invention. [Figure 14] 10A and 10B are diagrams illustrating a third aspect of the method for manufacturing the substrate coil according to the second embodiment of the present invention. [Figure 15] FIG. 10 is a plan view of a substrate coil according to a third embodiment of the present invention. [Figure 16] FIG. 10 is a cross-sectional view of a transformer according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] [Application example] An outline of an application example of the present invention will be explained below with reference to some of the drawings. A substrate coil 10 to which the present invention is applied is shown in FIG. 1. The substrate coil 10 is formed by stacking, for example, nine layers of substrates, from a first substrate 1 to a ninth substrate 9, each having a winding pattern, and electrically connecting the winding patterns (1a to 9a) of two consecutively stacked substrates with each other by, for example, via holes (VIA). As shown in FIG. 1, for example, the first substrate 1 has a first winding pattern 1a, which is an arc-shaped conductor pattern corresponding to the first layer of the substrate coil. is provided.

[0024] Here, as in the conventional technology shown in FIG. 4, when the connection points 101d to 108d in the winding patterns 101a to 109a of the substrates 101 to 109 are formed so as to be widely distributed from the inner periphery to the outer periphery on each of the winding patterns 101a to 109a, the area of ​​the winding pattern used as a coil is reduced, resulting in a decrease in winding efficiency.

[0025] When a high frequency current is applied to the substrate coil 110, each winding pattern 101a Since the current density on the inner side of 109a becomes higher, the current density of the innermost VIAs among the multiple VIAs becomes higher at conventional connection points 101d to 108d, which can cause inconveniences such as increased heat generation in some VIAs and reduced reliability.

[0026] In contrast, in this application example, as shown in Figure 6, the connection points of the winding patterns of each substrate are arranged on the outer periphery of each winding pattern, and the VIAs are arranged in parallel in one or two rows in the circumferential direction at the connection points. This increases the area that can be used as a coil in each winding pattern, making it possible to improve winding efficiency. Note that the connection points in this application example and the following examples correspond to connection parts of the present invention.

[0027] 7, even if the high-frequency current flows unevenly toward the inner periphery of the winding pattern due to the skin effect, it can be made to flow toward the outer periphery at connection points 2d and 3e, and then return from the outer periphery to the inner periphery at third winding pattern 3a on the third substrate 3. As a result, it is possible to prevent current density from concentrating in a specific via, improving reliability.

[0028] Example 1 The following describes in detail exemplary embodiments of the present invention with reference to the drawings (including the drawings already described in the application examples above). However, unless otherwise specified, the specific configurations described in the examples are not intended to limit the scope of the present invention to those configurations.

[0029] Fig. 1 shows a plan view of a substrate coil 10 according to an embodiment of the present invention. The substrate coil 10 according to this embodiment is formed by stacking nine layers of substrates, from a first substrate 1 to a ninth substrate 9, each having a winding pattern, and electrically connecting the winding patterns (1a to 9a) of two consecutively stacked substrates, to form a substrate coil with a total of eight turns. Fig. 1 shows the first substrate 1, which is located at the top, so that it can be seen.

[0030] The first substrate 1 is provided with a first winding pattern 1a, which is an arc-shaped conductor pattern corresponding to the first layer of the substrate coil. The first substrate 1 has an input terminal 1b connected to the first winding pattern 1a, and an output terminal 1c connected to a ninth winding pattern 9a on a ninth substrate 9 (not shown) in a manner that penetrates from the second substrate 2 to the eighth substrate 8. The first substrate 1 also has openings 1f, 1g, and 1h for inserting a magnetic core (described below). The winding pattern and the openings for inserting the magnetic core are also provided in common on the second substrate 2 to the ninth substrate 9 (2a-9a, 2f-9f, 2g-9g, 2h-9h).

[0031] FIG. 2 is a cross-sectional view of a transformer 50 constructed using a substrate coil 10 and a second substrate coil 40 having a different total number of turns. The transformer 50 is constructed by magnetically coupling the nine-layer (eight-turn) substrate coil 10 shown in FIG. 1 with a second substrate coil 40 having a different number of layers and turns via a magnetic core 60. A current is input to the substrate coil 10, which serves as one substrate coil, and an induced current flowing through the second substrate coil 40, which serves as the other substrate coil, is output and transformed. In this way, constructing the transformer 50 using multiple substrate coils 10 and 40 allows for a smaller size and a lower height of the transformer 50. Note that it is also possible to construct an inductor element by combining the substrate coil 10 and a magnetic core 60 in a similar manner.

[0032] The winding pattern provided on each substrate of the substrate coil may be a single turn, as in the first winding pattern 1a in Fig. 1, or may be a multi-turn. By making the winding pattern a single turn, the number of turns on the substrate can be increased to increase the total number of turns. Although this increases the number of turns, it has the advantage that the pattern can be made thicker and a large current can be passed through it. When multiple turns (multi-turns) are used, connection points are provided at the outer and inner ends of each winding pattern. The number of turns of the substrate coil 10 and the second substrate coil 40 may be the same or different. Furthermore, a normal wound coil may be used instead of the substrate coil 10 or the second substrate coil 40.

[0033] 3 is a schematic diagram showing the connection state of the first winding pattern 1a to the ninth winding pattern 9a on the first substrate 1 to the ninth substrate 9. As shown in the figure, on each substrate, the connection point connecting to the upper substrate and the connection point connecting to the lower substrate are separated, so one turn cannot be formed with one winding pattern, and a coil of eight turns is formed by stacking the nine substrates from the first substrate 1 to the ninth substrate 9.

[0034] 4 is a plan view illustrating the state of connection when the winding patterns 1a to 9a of each of the first to ninth substrates 1 to 9 are connected by a conventional method. Here, the winding patterns of each substrate are connected to one another by a plurality of interlayer conductive holes (via (VIA) holes, hereinafter simply referred to as VIAs). In reality, in a plan view of the substrate coil 110, only the VIA at the connection point 101d connecting the first winding pattern 101a and the second winding pattern 102a is visible, and the VIA at the connection point 108d connecting the eighth winding pattern 108a and the ninth winding pattern 109a from the connection point 102d connecting the second winding pattern 102a and the third winding pattern 103a is not actually visible. However, in the drawing, they are depicted as the VIA at the connection point 101d in order to indicate their relative positions.

[0035] 4, as described above, in the winding patterns 101a-109a of each of the substrates 101-109, the distance between the connection points for connecting to the upper substrate and the connection points for connecting to the lower substrate was large, which reduced the winding efficiency. Furthermore, the connection points 101d-108d were formed on each of the winding patterns 101a-109a from the inner periphery to the outer periphery, or were distributed widely in the circumferential direction, which further reduced the winding efficiency.

[0036] Furthermore, it is known that when a high-frequency current is applied to the substrate coil 110, the skin effect of the high-frequency current, as shown in Fig. 5, causes a high current density on the inner side of each of the winding patterns 101a-109a. (The arrows indicating the current indicate either the positive or negative direction of the AC current.) This results in a high current density in the innermost vias of the multiple vias at each of the connection points 101d-108d, which can cause problems such as increased heat generation in some vias and reduced reliability. Another problem is that the magnetic field caused by the current passing through each of the connection points 101d-108d varies greatly within each connection point.

[0037] In contrast, in this embodiment, as shown in FIG. 6, the connection points of the winding patterns of each substrate are arranged on the outer periphery of each winding pattern, and VIAs are arranged in parallel in one or two rows in the circumferential direction. This corresponds to making the connection portions elongated in the circumferential direction of the winding patterns. Here, VIAs correspond to connection means extending in the normal direction of the substrate coil. Furthermore, in the winding patterns of each substrate, the connection points with the winding pattern of the lower substrate and the connection points with the upper substrate are arranged side by side on the outer periphery of the winding patterns. More specifically, in FIG. 6, in the second winding pattern 2a of the second substrate 2, the connection points 2d for connection with the connection points 3e of the third winding pattern 3a of the third substrate 3 and the connection points 2e for connection with the first winding pattern (not shown) of the first substrate 1 are arranged side by side on the outer periphery of the second winding pattern 2a, with a gap 2i between both ends of the winding pattern 2a. Note that, here, the connection points are The connection point 3e and the connection point 2d correspond to a pair of connections between the two winding patterns.

[0038] As shown in FIG. 7, even if the high-frequency current flowing through the second winding pattern 2a of the second substrate 2 is biased toward the inner periphery of the winding pattern due to the skin effect (the arrows indicating the current indicate either the positive or negative direction of the AC current), the current will first flow toward the outer periphery at connection points 2d and 3e and then follow a path that returns from the outer periphery to the inner periphery at the third winding pattern 3a of the next substrate 3, thereby preventing the current density from concentrating in a specific via at connection points 2d and 3e.

[0039] 8 shows an example of a perspective view of the substrate coil 10 of this embodiment combined with a magnetic core 60. For simplicity, this figure shows only the winding 10a formed by the winding patterns 1a to 9a of the substrates 1 to 9. As such, in a plan view, the magnetic core 60 has a shape that is point-symmetrical with respect to the center of the winding 10a, a shape that spreads out in a fan shape from the center of the winding 10a toward the outer periphery, and is arranged to cover the winding 10a.

[0040] 9 shows plan views of the winding patterns 1a to 9a on the substrates 1 to 9 in this embodiment, as well as a plan view of the substrate coil 10 combined with a magnetic core 60. FIG. 9(a) is a pattern diagram of the winding patterns 1a to 9a on the first substrate 1 to the ninth substrate 9. FIG. 9(b) is a plan view of the substrate coil 10 combined with a magnetic core 60. In FIG. 9(b), to make the arrangement of each connection part easier to understand, cross sections of only the center core 60a, first side core 60b, and second side core 60c of the magnetic core 60 are shown.

[0041] In this embodiment, the winding 10a of the substrate coil 10 is formed by overlapping the winding patterns 1a to 9a on the first substrate 1 to the ninth substrate 9 shown in Fig. 9(a). Each of the winding patterns 1a to 9a has a roughly circular pattern with gaps provided between them, and the winding patterns 1a to 9a gradually rotate counterclockwise in order.

[0042] The winding pattern 1a has a gap between its two ends and a connection point 1d on the left side. Connection point 2e on the clockwise side across the gap between both ends of turn 2a is connected by a VIA. Similarly, connection point 2d on the counterclockwise side across the gap between both ends of winding pattern 2a and connection point 3e on the clockwise side across the gap between both ends of winding pattern 3a are connected by VIAs....Connection point 8d on the left counterclockwise side across the gap between both ends of winding pattern 8a and connection point 9e on the clockwise side across the gap between both ends of winding pattern 9a are connected by VIAs.

[0043] As shown in FIG. 9(b), connection points 1d (2e), 2d (3e), Connection points 3d (4e) and 4d (5e) are located in the gap between the first side core 60b and the center core 60a of the magnetic core 60. Similarly, connection points 5d (6e), 6d (7e), 7d (8e), and 8d (9e) are located in the gap between the second side core 60c and the center core 60a of the magnetic core 60. In this way, by symmetrically arranging the connection points of the winding patterns 1a to 9a of each substrate 1 to 9 between the center core 60a of the magnetic core 60 and the first side core 60b and the second side core 60c, magnetic field disturbances due to vias at each connection point can be uniformed in the magnetic circuits on both side core sides, thereby stabilizing the function as an inductor element or transformer. Similarly, although not shown, the connection points of the winding patterns 1a to 9a of each substrate may be located in a location not covered by the magnetic core 60. This prevents magnetic disturbance caused by current flowing through the through-holes at each connection point from This can avoid affecting the magnetic field passing through the core 60. As a result, it is possible to stabilize the function as an inductor or a transformer.

[0044] <Example 2> Next, a description will be given of Example 2 of the present invention. In Example 1, an example was described in which consecutively overlapping winding patterns 1a to 9a of the first to ninth substrates 1 to 9 are connected to each other using VIAs at connection points located on the outer periphery of each of the winding patterns 1a to 9a, but in this example, an example will be described in which consecutively overlapping winding patterns are connected to each other by penetrating through holes at connection points protruding from each of the winding patterns 1a to 9a toward the outer periphery.

[0045] 10 shows a perspective view of the winding 20a of the substrate coil in this embodiment. In this embodiment, as in embodiment 1, the winding 20a is formed by connecting the connection points of the winding patterns 11a to 19a on each substrate. However, as shown in embodiment 1, when connecting the connection points of the winding patterns 1a to 9a with vias, it is necessary to connect consecutively overlapping winding patterns with vias each time the substrates 1 to 9 are overlapped, which can complicate the manufacturing process.

[0046] In contrast, in this embodiment, the connection points of each winding pattern 11a-19a are arranged so as to protrude outward from the outer periphery of the winding patterns 11a-19a. The connection points of consecutively overlapping winding patterns are arranged so that they overlap in a plan view. The connection points are then connected by through-holes that penetrate the entire substrate coil. This allows the consecutively overlapping winding patterns to be connected to each other by forming through-holes at the connection points after the first through ninth substrates are stacked, simplifying the manufacturing process.

[0047] Fig. 11 shows plan views of the winding patterns 11a to 19a on each substrate in this embodiment, and a plan view of the winding 20a of the substrate coil combined with the magnetic core 60. Fig. 11(a) is a pattern diagram of the winding patterns 11a to 19a on the first to ninth substrates. Fig. 11(b) is a plan view of the winding 20a of the substrate coil combined with the magnetic core 60. In Fig. 11(b), to make the arrangement of each connection part easier to understand, only the cross sections of the center core 60a, first side core 60b, and second side core 60c of the magnetic core 60 are shown.

[0048] 11(a), the winding 20a of the substrate coil is formed by overlapping the winding patterns 11a to 19a of the first to ninth substrates. Each of the winding patterns 11a to 19a constituting the winding 20a is a roughly circular pattern with gaps provided, and the winding patterns 11a to 19a are gradually rotated counterclockwise in order.

[0049] In this embodiment, the connection points 11e, 11d to 19d, and 19e of the winding patterns 11a to 19a are arranged so as to protrude further outward from the outer periphery of the arc of the winding patterns 11a to 19a. The connection point 11d on the left side across the gap between both ends of the winding pattern 11a and the connection point 11d on the right side across the gap between both ends of the winding pattern 12a are arranged so as to protrude further outward from the outer periphery of the arc of the winding patterns 11a to 19a. The connection points 12e are arranged to overlap in a plan view and are connected by a through-hole.

[0050] Similarly, a connection point 12d on the counterclockwise side across a gap between both ends of the winding pattern 12a, a connection point 13e on the clockwise side across a gap between both ends of the winding pattern 13a, and a connection point 18d on the counterclockwise side across a gap between both ends of the winding pattern 18a. The winding pattern 19a is arranged so that the connection points 19e on the clockwise side overlap with a gap between both ends of the winding pattern 19a, and is connected by a through-hole.

[0051] 11(b), connection point 11d (12e), connection point 12d (13e), connection point 13d (14e), and connection point 14d (15e) are arranged in the gap between the first side core 60b and the center core 60a of the magnetic core 60. Similarly, connection point 15d (16e), connection point 16d (17e), connection point 17d (18e), and connection point 18d (19e) are arranged in the gap between the second side core 60c and the center core 60a of the magnetic core 60.

[0052] Here too, by symmetrically arranging the connection points of the winding patterns 11a-19a on each board between the center core 60a and each of the side cores 60b, 60c of the magnetic core 60, magnetic disturbances caused by currents flowing through the through-holes at each connection point can be uniformed in the magnetic circuits on both side cores 60b, 60c sides, thereby stabilizing the function as an inductor or transformer. Similarly, although not shown, the connection points of the winding patterns 11a-19a on each board may be arranged in a location not covered by the magnetic core 60. This prevents magnetic disturbances caused by currents flowing through the through-holes at each connection point from affecting the magnetic field passing through the magnetic core 60. As a result, the function as an inductor or transformer can be stabilized.

[0053] Next, a manufacturing procedure for the substrate coil of this example will be described with reference to FIG. 12. As shown in FIG. 12(a), in this example, the fourth substrate 14 and the fifth substrate 15 are formed from a common double-sided substrate, with winding patterns 14a and 15a formed on both sides. Then, as shown in FIGS. 12(b) to 12(e), the third substrate 13 on which winding pattern 13a is formed to the first substrate 11 on which winding pattern 11a is formed are stacked on the winding pattern 14a side. Meanwhile, the sixth substrate 16 on which winding pattern 16a is formed to the ninth substrate 19 on which winding pattern 19a is formed are stacked on the winding pattern 15a side. Finally, as shown in FIG. 12(f), through-holes are formed and the respective connection points are connected.

[0054] Next, another embodiment of the manufacturing procedure for the substrate coil will be described with reference to Fig. 13. In this example, as shown in Fig. 13(a), fourth substrate 14 and fifth substrate 15 are formed from a common double-sided substrate, and winding patterns 14a and 15a are formed on both sides of the substrate. At this point, embedded through-holes are formed in the double-sided substrate, and winding patterns 14a and 15a are connected to them.

[0055] Next, as shown in FIGS. 13(b) to 13(e), the third substrate 13 to the first substrate 11 are placed on the winding pattern 14a side, and the sixth substrate 16 to the ninth substrate 19 are placed on the winding pattern 15a side. Finally, as shown in FIG. 13(f), through-holes are formed and the remaining connection points are connected. In this example, the connection points 14d (15e) between the winding patterns 14a and 15a are connected by embedded through-holes, so they do not necessarily need to protrude outward from the winding patterns 14a, 15a as shown in FIG. 11. The connection points 14d (15e) may also be provided inside the arc portions of the winding patterns 14a, 15a.

[0056] In this case, the embedded through hole at the connection point does not need to be in the form of four through holes lined up in the circumferential direction, as in other connection points, and may be formed, for example, from a single through hole with a relatively large cross-sectional area.

[0057] Furthermore, a third embodiment of the manufacturing procedure for the substrate coil will be described with reference to FIG. 4 shows the substrate coil 20 produced in this embodiment. Fig. 14(a) is a schematic diagram showing the connection state of the substrate coil 20. Fig. 14(b) is a cross-sectional view of the substrate coil 20. In this embodiment, a combination of buried through-holes and penetrating through-holes is used.

[0058] 14(a), a first winding pattern 11a and a second winding pattern 12a, a third winding pattern 13a and a fourth winding pattern 14a, a fifth winding pattern 15a and a sixth winding pattern 16a, and a seventh winding pattern 17a and an eighth winding pattern 18a are formed on the top and bottom surfaces of a double-sided core substrate, respectively, and are connected by embedded through-holes to form pairs. These four pairs of winding patterns are further connected by penetrating through-holes and stacked to form a substrate coil 20.

[0059] 14(b), the embedded through-holes in the four core substrates connect connection points 11d and 12e, connection points 13d and 14e, connection points 15d and 16e, and connection points 17d and 18e. These four embedded through-holes are provided within the arc-shaped portions of the winding patterns 11a to 18a in top view. Alternatively, they may be provided in the same positions in top view.

[0060] Furthermore, through-holes connect connection points 12d and 13e, connection points 14d and 15e, connection points 16d and 17e, and connection points 18d and 19e. These four through-holes connect the connection points at portions that protrude further outward from the outer periphery of the arc-shaped portions of winding patterns 11a to 18a.

[0061] In Figure 14(a), connection points are indicated by black dots, buried through-holes and penetrating through-holes that connect connection points are indicated by solid lines, and penetrating through-holes that do not connect connection points are indicated by dotted lines. In Figure 14(b), buried through-holes are indicated in black. Penetrating through-holes are hatched with diagonal lines, and the areas that connect winding patterns are also indicated in black. The number of winding patterns is not limited to nine, and the number of core substrates is not limited to four.

[0062] Example 3 Next, a third embodiment of the present invention will be described. In this embodiment, the connection points of each winding pattern are arranged so as to protrude from the arc of the winding pattern on each substrate toward the outer periphery, and the connection points of consecutively overlapping winding patterns are arranged so as to overlap in plan view, and the connection is achieved by plating the side surfaces of the layers sandwiched between the connection points.

[0063] 15 shows a plan view of the substrate coil 30 in this embodiment. In this embodiment, as in embodiments 1 and 2, the winding is formed by connecting the connection points of the winding patterns 21a to 29a on the first substrate 21 to the ninth substrate 29. However, as shown in embodiments 1 and 2, when the connection points of the winding patterns are connected with vias or through holes, the structure of the connection points can become complicated.

[0064] In contrast, in this embodiment, the connection points of the winding patterns 21a to 29a are connected by plating the side surfaces of the insulating layer (substrate) between the connection points of consecutively overlapping winding patterns. This makes it possible to minimize the area of ​​the connection points as viewed from the normal direction of the winding patterns 21a to 29a, improve winding efficiency, and realize a smaller and thinner substrate coil 30.

[0065] This also reduces manufacturing costs, reduces the parasitic L and C in the substrate coil 30, prevents malfunctions in devices incorporating the substrate coil 30, and reduces noise. Furthermore, as with Examples 1 and 2, it is possible to prevent a decrease in reliability due to overheating of the connection measurement area when a high-frequency current is passed through the connection, which can be prevented. In this case, the connection points of each winding pattern may protrude toward the outer periphery, as shown in FIG. 15 for connection point 21d of the first winding pattern 21a. Alternatively, the connection points may not protrude toward the outer periphery, and the arc-shaped side surfaces of the winding patterns may be plated as they are. In this example, the plating applied to the side surfaces of the substrate corresponds to the conductive portion.

[0066] Example 4 Next, a fourth embodiment of the present invention will be described. In the above embodiments, a transformer having a substrate coil in which only a portion of the winding pattern is covered by a magnetic core is described, but in this embodiment, a transformer having a substrate coil in which the winding pattern is not covered by a magnetic core, and a transformer in which a path core structure is applied between two types of coils will be described.

[0067] FIG. 16 is a cross-sectional view of a transformer according to this embodiment. FIG. 16(a) is a cross-sectional view of a transformer 51 including a substrate coil 10 and a second substrate coil 40 whose winding patterns are not covered by a magnetic core. The magnetic core 61 is a rod core located near the center of the winding patterns of each substrate so as to be surrounded by the winding patterns. In the configuration of FIG. 16(a), the connection points (not shown) on the winding patterns are not covered by the magnetic core 61. This avoids the drawbacks of disturbances in the magnetic field generated by the current flowing through the winding patterns and unevenness in the amount of magnetic field passing between side cores (not shown), and allows for greater freedom in arranging the connection points.

[0068] FIG. 16(b) is a cross-sectional view of a transformer 52 employing a pass-core structure between a substrate coil 10 equipped with a magnetic core 62 and a second substrate coil 40. To improve the transformer's operating efficiency, an external resonator L is attached. However, arranging the transformer and the resonator L horizontally increases the mounting area, while stacking them vertically requires shielding, resulting in increased height. Therefore, in either case, it is difficult to achieve a compact and low-profile transformer. In the configuration of FIG. 16(b), by inserting a magnetic core 62a between the substrate coil 10 and the second substrate coil 40 and applying a pass-core structure, it becomes possible to induce resonance in the substrate coil 10 and the second substrate coil 40 while achieving a compact and low-profile transformer 52.

[0069] Also, similar to the transformer 50 of Example 1, the number of turns of the substrate coil 10 and the number of turns of the second substrate coil 40 may be the same or different, and a normal wound coil may be used instead of the second substrate coil 40.

[0070] In the following, the constituent elements of the present invention will be described with reference to the reference numerals in the drawings in order to make it possible to compare the constituent elements of the present invention with the configurations of the embodiments. <Invention 1> A substrate coil (10) formed by laminating winding patterns (1a-9a) provided on a plurality of layers (1-9) constituting a multilayer substrate and electrically connecting the winding patterns (1a-9a) at connection portions (1d-8d, 2e-9e) in the winding patterns (1a-9a), The substrate coil (10) is characterized in that the connection portions (1d to 8d, 2e to 9e) in the winding patterns (1a to 9a) have an elongated shape extending in the circumferential direction of the winding patterns when viewed from the normal direction of the substrate coil (10), and are arranged on the outer periphery of the winding patterns (1a to 9a). [Explanation of symbols]

[0071] 1 to 9, 11 to 19, 21 to 29...1st board to 9th board 1a to 9a, 11a to 19a, 21a to 29a... 1st winding pattern to 9th winding pattern 1b, 11b...input terminal 1c, 11c...output end 1d~8d, 11d~18d... Connection points 2e~9e, 12e~19e... Connection points 10, 20, 30... Substrate coil 60 Magnetic Core

Claims

1. A substrate coil formed by laminating winding patterns provided on a plurality of layers constituting a multilayer substrate and electrically connecting the winding patterns at connection portions of the winding patterns, the connection portion of the winding pattern has an elongated shape extending in a circumferential direction of the winding pattern when viewed from a normal direction of the substrate coil, and is disposed on an outer periphery of the winding pattern; a magnetic core including two magnetic circuits arranged so as to cover a part of the winding pattern in point symmetry with respect to the center of the winding pattern when viewed from the normal direction of the substrate coil; A substrate coil characterized in that the connection portion is arranged in a portion covered by the two magnetic circuits, when viewed from the normal direction of the substrate coil, so as to be point-symmetrical with respect to the center of the winding pattern.

2. 2. The substrate coil of claim 1, wherein the connection portions of two of the winding patterns provided on the multiple layers that are overlapped and connected to each other are positioned so as to overlap each other on the outer periphery of the winding patterns when viewed from the normal direction of the substrate coil, and the connection portions are connected to each other by a connection means extending in the normal direction of the substrate coil.

3. 3. The substrate coil according to claim 2, wherein the pair of connection portions of the two winding patterns to be connected to each other and the pair of connection portions of the next two winding patterns to be connected are arranged so as to be lined up consecutively on the outer periphery of the winding pattern.

4. the connecting portion is provided at a portion that protrudes further outward from the outer periphery of the winding pattern, 4. The substrate coil according to claim 2, wherein the connecting means is a through hole that penetrates a plurality of layers.

5. The connecting means is provided on the connecting portion of the two winding patterns to be connected to each other.

4. The substrate coil according to claim 2, wherein the via holes are arranged in parallel in one or two rows in the circumferential direction of the wire pattern and are formed between the connection portions in the normal direction of the winding pattern.

6. 4. The substrate coil according to claim 2, wherein the connecting means is a conductive portion provided on a side surface of the connecting portion of an insulating layer formed between the two winding patterns to be connected to each other.

7. A transformer having a plurality of coils arranged so as to overlap each other, including a magnetic core, inputting a current into one coil and outputting an induced current flowing through another coil, the magnetic core has a portion disposed to pass through the center of the plurality of coils; A transformer, wherein at least some of the plurality of coils are substrate coils according to any one of claims 1 to 6.

8. 8. The transformer according to claim 7, wherein the magnetic core has a path core structure in which a core is disposed between coils in the plurality of coils.

9. 8. The transformer according to claim 7, wherein the magnetic core is a rod core having a rod shape that passes through the centers of the plurality of coils.

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