JP7567334B2 - Substrate coils and transformers - Google Patents

Description

The present invention relates to substrate coils and transformers.

A technology has been proposed to form a transformer with a relatively large electric capacity by stacking circuit boards with windings inside that make up the transformer and connecting each winding with through holes (see, for example, Patent Document 1).

However, the above technology involves stacking patterns with relatively wide windings, so in order to ensure current capacity, it is necessary to connect each winding with many through holes. If there are many connections using through holes, a loss in the number of turns occurs, making it difficult to achieve a smaller and thinner substrate coil.

A multi-layer transformer substrate is also known in which multiple substrates with coil patterns on their surfaces are stacked together, and the coil patterns located above and below are selectively connected to form windings on the excitation side and windings on the receiving side (see, for example, Patent Document 2).

However, the arrangement of the connections that electrically connect the coil patterns is not described. For example, if there are scattered connection parts with an area of a certain size or more, the winding efficiency may decrease and parasitic components such as parasitic C and parasitic L may increase.

JP 2001-358427 A JP 2010-093174 A Japanese Patent Application Publication No. 09-289128

The present invention was made in consideration of the above problems, and its purpose is to provide a technology that enables the miniaturization and low profile of substrate coils and transformers that include substrate coils, and that can suppress parasitic components caused by connections that electrically connect winding patterns in substrate coils.

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 connection portions of the winding pattern have an elongated shape extending in a predetermined direction in a plan view, and the connection portions are connected to each other by through holes that are conductive in a direction perpendicular to the plane of the winding pattern,
Among the winding patterns provided on the plurality of layers, a pair of connection parts of two overlapping winding patterns to be connected to each other and a pair of connection parts of two winding patterns to be connected next are formed so as not to overlap in a plan view and to be aligned in a direction perpendicular to the predetermined direction.
It is a substrate coil.

According to the present invention, the connection parts that connect the winding patterns to each other have an elongated shape that extends in a predetermined direction, and each pair of connected connection parts is formed to be aligned in a direction perpendicular to the predetermined direction. This allows the connection parts to be efficiently arranged densely on the winding pattern in a plan view, and increases the area on the winding pattern that can be used as a coil. As a result, it is possible to achieve a smaller and thinner substrate coil. In addition, the area of the connection parts themselves can be reduced, making it possible to suppress parasitic components due to the connection parts.

In addition, in the present invention, the winding pattern may be an arc-shaped single-turn pattern, and the predetermined direction may be the width direction of the gaps at both ends of the winding pattern. In this way, the connection parts are arranged in the width direction of the gaps at both ends of the winding pattern, so that the winding pattern is more densely packed in a plan view, and since the winding pattern is an arc-shaped single-turn pattern, it is possible to achieve a smaller and thinner substrate coil. Here, the gaps at both ends of the winding pattern refer particularly to the gaps in the arc-shaped portions that form the coil.

The present invention may also be a substrate coil characterized in that the through holes are arranged in one or two rows in parallel in the direction in which the connection parts extend in the connection parts. This allows the through holes to be arranged in an orderly manner in the connection parts, increasing the density of the through holes and reducing the area of each connection part.

The present invention may also be a substrate coil characterized in that the connection portion in the winding pattern is connected outside the winding pattern in a plan view. This more reliably prevents the connection portion from reducing the area of the portion of the winding pattern that functions as a coil. It also prevents the magnetic field generated by the current passing through the through hole from disrupting the flow of the magnetic field generated by the current flowing on the winding pattern.

In addition, in the present invention, the through holes may be embedded through holes that penetrate only some of the layers of the multilayer board, and the pair of connection parts of the two outer winding patterns in the multilayer board may be located farther from the center of the winding patterns in a plan view than the pair of connection parts of the two inner winding patterns. In this way, the through holes penetrate only the layers between the winding patterns that are connected to each other, so they do not interfere with the winding patterns of other layers. Therefore, it is possible to increase the degree of freedom in the placement of the through holes and the connection parts. This makes it possible to more reliably increase the winding efficiency of each winding pattern, and to achieve a smaller and thinner board coil.

In addition, in the present invention, the through holes may be through holes that penetrate the multilayer substrate, and in the multilayer substrate, the pairs of connection parts of each winding pattern may be arranged in a position farther or closer to the center of the winding pattern in a planar view depending on the order of stacking. This also allows the connection parts having through holes to be arranged densely in a planar view on the winding pattern, making it easier to achieve a smaller and thinner substrate coil. In addition, since the connection parts can be arranged generally outside the arc-shaped portion of the winding pattern, it is possible to increase the winding efficiency of the winding pattern.

The present invention may also provide a substrate coil that includes a magnetic core arranged to cover a part of the winding pattern in a plan view, and the connection portion is arranged in a portion where the magnetic core is not provided in a plan view. Here, the magnetic core increases the efficiency of the flow of the magnetic field generated by the coil windings. In contrast, the magnetic field generated by the current passing through the through hole has a different direction from the magnetic field generated by the coil windings, and may cause disturbance of 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, so that the magnetic field generated by the current passing through the through hole can be prevented from disturbing the flow of the magnetic field generated by the magnetic core. As a result, it is possible to more reliably increase the efficiency and increase the flow of the magnetic field generated by the windings of the substrate coil.

The present invention may also provide a transformer in which multiple coils are arranged so as to overlap, a current is input to one coil, and an induced current flows through the other coils, the transformer further comprising a magnetic core arranged to pass through the center of the multiple coils, and at least some of the multiple coils are substrate coils having the above characteristics. This makes it possible to achieve a smaller and thinner transformer while maintaining the stability of the original functions of the transformer.

In the present invention, the magnetic core may be a transformer having a path core structure in which a core is disposed between the coils of the multiple coils. Here, when attaching an external resonator L to improve the operating efficiency of the transformer, the mounting area increases when the transformer and the resonator L are arranged horizontally, and a shield is required when stacked vertically, resulting in an inconvenience of increased height. By inserting a magnetic core between two types of substrate coils and applying a path core structure, it is possible to induce resonance in the two types of substrate coils while achieving a smaller and lower-profile transformer.

The present invention may also be a transformer characterized in that the magnetic core is a rod core made of a rod-shaped core that passes through the center of the multiple coils. In this configuration, the connection points on the winding pattern are not covered by the magnetic core, and it is possible to avoid the drawbacks of disturbances in the magnetic field generated by the current flowing through the winding pattern and uneven amounts of magnetic fields passing between side cores, and to increase the freedom of arrangement of the connection points.

The present invention may also be a transformer characterized in that the magnetic core is arranged so as to cover a portion of the coils in plan view, and the connection portion is arranged in a portion where the magnetic core is not provided in plan view. This makes it possible to more reliably increase and streamline the flow of the magnetic field generated by the windings in the substrate coil that constitutes the transformer.

In addition, in the present invention, the means for solving the above problems can be used in combination as much as possible.

According to the present invention, it is possible to reduce the loss in the number of turns in the winding pattern, thereby making it possible to realize a smaller and thinner substrate coil. It is also possible to suppress parasitic components due to the connection parts and improve the reliability of the substrate coil's conductivity. By making the substrate coil, it is also possible to miniaturize electronic devices by incorporating them into electronic circuit boards, reduce the number of parts mounted, and reduce production costs.

13 is a diagram for explaining connection points in a conventional substrate coil, which are portions that penetrate each of the first to eighth substrates to connect the substrates to each other or connect winding patterns on the substrates to each other. FIG. 2 is a plan view of a substrate coil according to the first embodiment. 11 is a cross-sectional view of a transformer formed using a substrate coil and a second substrate coil. FIG. 4A to 4C are diagrams for explaining in detail the connection state of each winding pattern in the substrate coil in the first embodiment. FIG. 2 is a perspective view of a substrate coil combined with a magnetic core in the first embodiment. 4 is a plan view showing the winding patterns on each substrate in the first embodiment, and a combination of a substrate coil and a magnetic core. FIG. 13 is a diagram for explaining in detail the connection state of each winding pattern in the substrate coil in Example 2. FIG. 13 is a plan view showing the winding patterns on each substrate in the second embodiment, and a combination of a substrate coil and a magnetic core. FIG. 13 is a diagram for explaining in detail the connection state of each winding pattern in the substrate coil in Example 3. FIG. FIG. 11 is a cross-sectional view of a transformer according to a fourth embodiment.

[Application example]
In this application example, a spiral substrate coil made up of a plurality of winding patterns, each having one turn, is applied to a multi-layer substrate.

At the connection part of the arc-shaped winding patterns, the upper winding pattern and the lower winding pattern are electrically connected vertically by conductive holes called through holes. The winding patterns connected by the through holes are further stacked to form a substrate coil. There are gaps at both ends of the winding pattern having an arc-shaped portion, and the connection part has an elongated shape extending along the width direction of the gap in a plan view. Furthermore, a pair of connection parts of two winding patterns that are connected to each other and a pair of connection parts of two winding patterns that are next connected are formed in positions on the substrate coil that do not overlap in a plan view. Furthermore, the through holes are arranged in parallel in one or two rows at the connection part in the direction in which the connection parts extend.

The through holes may be embedded through holes that penetrate only some of the layers of the multilayer board. The solid lines connecting the connection points shown by black dots in FIG. 4(a) are embedded through holes. As shown in FIG. 4(a), in the multilayer board, the embedded through holes connecting two winding patterns stacked on the outer side in the stacking direction are positioned farther from the center of the winding patterns in a plan view of the board coil than the embedded through holes connecting two winding patterns stacked on the inner side. At least the embedded through holes connecting the two innermost winding patterns may be positioned inside the gap between both ends of the winding patterns in a plan view. All of the connection parts have an elongated shape extending in the width direction of the gap and are arranged in parallel in the width direction and perpendicular to the width direction.

The through holes may be through holes that penetrate the multilayer board. In this case, the winding patterns are connected using through holes, as shown by the solid lines connecting the connection points shown by black dots in Figure 7(a). In the example shown in Figure 7, in the multilayer board, all of the connection parts have an elongated shape that extends in the width direction of the gap, and are arranged in parallel in the width direction and perpendicular to the width direction.

The substrate coil may include a magnetic core that increases the efficiency of the flow of the magnetic field generated by the windings of the coil. In the substrate coil of this application example, a part of the winding pattern may be covered by the magnetic core in a plan view, and the connection part may be disposed in a part not covered by the magnetic core. This makes it possible to prevent the magnetic field generated by the current passing through the through hole in the connection part from disturbing the flow of the magnetic field generated by the magnetic core. As a result, it is possible to more reliably increase the efficiency and increase the flow of the magnetic field generated by the windings of the substrate coil.

In addition, by arranging multiple substrate coils with the above characteristics and different numbers of turns in a stacked manner, it is possible to form a transformer by inputting a current into one substrate coil and outputting an induced current flowing through the other substrate coils.

Example 1
Hereinafter, a substrate coil and a transformer according to a first embodiment of the present invention will be described in detail with reference to the drawings. Note that the substrate coil and the transformer according to the present invention are not intended to be limited to the following configurations.

<About the printed circuit board coil>
Fig. 1 is a diagram for explaining connection points in a conventional substrate coil, which are portions that penetrate each of the first substrate 11 to the eighth substrate 81 to connect the substrates to each other or the winding patterns on the substrates to each other. Fig. 1(a) is a plan view showing the arrangement of the connection points, and Fig. 1(b) is a schematic diagram showing the connection relationship between each winding pattern and each connection point. The connection points are connected to each other by through holes that are conductive in a direction perpendicular to the plane of the winding patterns. The inside of the through holes is filled with a paste-like insulating resin and conductive plating.

In the plan view shown in FIG. 1(a), the substrate coil 100 is formed by stacking eight layers of substrates, from a first substrate 11 to an eighth substrate 81, each having a winding pattern, and electrically connecting the winding patterns of two consecutively stacked substrates to form a coil with eight turns. In FIG. 1(a), the first substrate 11, which is located at the top, is visible.

The first board 11 is provided with a first winding pattern 11a, which is an arc-shaped conductor pattern corresponding to the first layer of the coil. It also has an input terminal 11b connected to the first winding pattern 11a, and an output terminal 11c connected to the eighth winding pattern 81a in the eighth board 81 (not shown) in a manner that penetrates from the second board 21 to the seventh board 71. It also has openings 11f, 11g, and 11h for inserting a magnetic core (described below). The winding pattern and openings for inserting the magnetic core are also provided in common on the second board 21 to the eighth board 81 (21a to 81a, 21f to 81f, 21g to 81g, 21h to 81h).

As shown in FIG. 1(a), eight connection points are formed around the first winding pattern 11a on the plane of the first substrate 11, from connection point 11d (21e) to connection point 71d (81e). The number of connection points is the same as the number of the eight layers of substrates from the first substrate 11 to the eighth substrate 81. Four through holes are provided at each connection point, penetrating each substrate from the first substrate 11 to the eighth substrate 81. Note that the first winding pattern 11a shown in FIG. 1(a) is a single turn, but may be a multi-turn. However, in the case of a multi-turn, the number of connection points required to obtain the same total number of turns can be reduced compared to the case of a single turn, but the current capacity is reduced. The same can be said for the second winding pattern 21a to the eighth winding pattern 81a.

As shown in FIG. 1(b), the through-holes at each connection point penetrate each of the first board 11 to the eighth board 81 so as to connect to the winding pattern in a specific two-layer board and not to the winding patterns in the other boards. For example, the through-hole at connection point 21d (31e) connects to connection point 21d in the second winding pattern 21a and connection point 31e in the third winding pattern 31a, and penetrates each of the first board 11 to the eighth board 81 without connecting to the other winding patterns.

As shown in FIG. 1B, for the first winding pattern 11a to the eighth winding pattern 81a, the two winding patterns that are in an overlapping positional relationship in a plan view are connected by through holes at the connection points. The first winding pattern 11a in the outermost first substrate 11 and the eighth winding pattern 81a in the eighth substrate 81 are also connected by through holes at connection points 81d and 11e. The connection points are indicated by black dots, through holes that connect the connection points are indicated by solid lines, and through holes that do not connect the connection points are indicated by dotted lines. In the conventional substrate coil 100 shown in FIG. 1, the connection points are scattered in a plan view. Therefore, the area of each winding pattern becomes large in order to connect with the connection points, making it difficult to realize a small size and low height of the substrate coil 100. In addition, parasitic C and parasitic L are likely to occur. Therefore, in Example 1, we consider an example in which the connection points are densely arranged on each winding pattern to suppress the increase in the area of each winding pattern and the parasitic components, with the aim of achieving a smaller and lower-profile substrate coil 100.

Figure 2 is a plan view of the substrate coil 10 according to the first embodiment. The substrate coil 10 according to the first embodiment is also an example in which a coil equivalent to seven turns is formed by stacking eight layers of substrates, the first substrate 1 to the eighth substrate 8, each having a winding pattern, and electrically connecting the winding patterns of two consecutively stacked substrates, but the number of substrate layers is not limited to eight. Here, the first substrate 1 to the eighth substrate 8 correspond to the multiple layers that make up the multilayer substrate in the present invention.

Although not shown in the plan view shown in FIG. 2, compared to the plan view shown in FIG. 1(a), the connection points are densely arranged in plan view in the board coil 10 and near the arc-shaped coil portion, which makes it possible to reduce the area of the first winding pattern 1a to the eighth winding pattern 8a. The board coil 10 shown in FIG. 2 is the same as the board coil 100 shown in FIG. 1(a) in that the winding patterns 2a to 8a similar to the winding pattern 1a, and the openings (2f to 8f, 2g to 8g, 2h to 8h) similar to the openings 1f, 1g, and 1h for inserting the magnetic core are also provided in the second board 2 to the eighth board 8. Here, the connection points correspond to the connection parts in this invention.

Figure 3 is a cross-sectional view of a transformer 30 constructed using a substrate coil 10 and a second substrate coil 20 with a different number of turns. The transformer 30 is constructed by magnetically coupling the eight-layer (eight turns) substrate coil 10 shown in Figure 2 with a second substrate coil 20 with a different number of turns and turns using a magnetic core 40. In this way, by constructing the transformer 30 using the substrate coils 10 and 20, it is possible to achieve a smaller size and a lower height. It is also possible to construct an inductor element by combining the substrate coil 10 and the magnetic core 40 in a similar manner.

Next, the connection state of each winding pattern in the substrate coil 10 in the first embodiment will be described in detail with reference to FIG. 4. FIG. 4(a) is a schematic diagram showing the arrangement of connection points in the winding patterns of each substrate constituting the substrate coil 10. FIG. 4(b) is a cross-sectional view of the winding patterns in the substrate coil 10 and the vicinity of the connection points. In this example, in addition to through holes penetrating the entire substrate 10, so-called embedded through holes, which are through holes that connect the winding patterns of two specific layers, are used. These embedded through holes are introduced to enable the substrate coil 10 to be made smaller and lower in height by increasing the degree of freedom in the position of the through holes. In this example, if the through holes are arranged in the arc-shaped portion of the winding pattern, the area used as a coil is reduced and the winding efficiency is reduced, so the through holes are arranged outside the arc-shaped portion of the winding pattern.

As shown in the substrate coil 10 in FIG. 4(a), the embedded through hole (embedded through hole connecting connection point 4d and connection point 5e) connecting the fourth winding pattern 4a and the fifth winding pattern 5a, which are formed on the innermost side of the winding patterns constituting the substrate coil 10, is closest to the center of all the winding patterns in the substrate coil 10 in a planar view. As for the other embedded through holes, they move away from the center of all the winding patterns in the substrate coil 10 in a planar view as they move toward the winding patterns outside the fourth winding pattern 4a and the fifth winding pattern 5a. The embedded through hole (embedded through hole connecting connection point 8d and connection point 1e) connecting the winding patterns in the outermost layer is located in a position farthest from the center of all the winding patterns in the substrate coil 10 in a planar view.

As shown in the schematic diagram of the cross section of the substrate coil 10 in FIG. 4(b), the embedded through hole connecting the connection point 4d and the connection point 5e is in the center, and the embedded through hole connecting the connection point 3d and the connection point 4e, the embedded through hole connecting the connection point 2d and the connection point 3e, and the embedded through hole connecting the connection point 1d and the connection point 2e are in a symmetrical positional relationship with the embedded through hole connecting the connection point 5d and the connection point 6e, the embedded through hole connecting the connection point 6d and the connection point 7e, and the embedded through hole connecting the connection point 7d and the connection point 8e, with the space between the fourth winding pattern 4a and the fifth winding pattern 5a as the boundary. Note that the number of winding patterns is not limited to eight.

The manufacturing process for the substrate coil 10 in Figure 4 is as follows. First, winding patterns are provided on both sides of the substrate, and new layers are laminated on both sides of the core material to which they are connected by through holes. Next, holes are drilled in the layers, plated and filled to form buried through holes. Next, the winding pattern is formed on top of the buried through holes. This process is repeated until the outermost layer is formed, at which point solder resist is applied and the exterior is processed. Note that there may be multiple core materials, and a new layer may be laminated on each of the core materials.

Figure 5 is a perspective view of the substrate coil 10 in Example 1 combined with a magnetic core 40. For simplicity, the figure shows only the coil portion formed by the winding patterns of each substrate. Thus, the magnetic core 40 has a shape that is point-symmetrical with respect to the center of the winding pattern in a plan view, and has a shape that spreads out in a fan shape from the center of the winding pattern toward the outer periphery. The first winding pattern 1a is only partially covered by the magnetic core 40. This magnetic core 40 is used to obtain higher inductance by more efficiently passing the magnetic field generated by the current flowing through the first winding pattern 1a to the eighth winding pattern 8a, or to strengthen the magnetic coupling when constructing a transformer.

Here, the direction of the current flowing from connection point 1d to connection point 2e (not shown) is different from the direction of the current flowing on the first winding pattern 1a, and the directions of the magnetic forces generated from these currents are also different. Therefore, when the magnetic field generated around connection point 1d increases, the magnetic field passing through the magnetic core 40 is disturbed. Therefore, connection point 1d is located in a part that is not covered by the magnetic core 40. Note that FIG. 5 illustrates the first winding pattern 1a on the first substrate 1, but the second winding pattern 2a to the eighth winding pattern 8a are common in that only a part of the winding pattern is covered by the magnetic core 40 and that the connection points are located in parts that are not covered by the magnetic core 40.

Fig. 6 is a plan view of the winding patterns on each substrate in the first embodiment, and of the substrate coil 10 combined with the magnetic core 40. Fig. 6(a) is a plan view of the winding patterns 1a to 8a on the first substrate 1 to the eighth substrate 8. Fig. 6(b) is a plan view of the substrate coil 10 combined with the magnetic core 40, with the winding patterns 1a to 8a stacked in this order. Note that in Fig. 6(b), in order to make the winding patterns 1a to 8a easier to see, only the cross sections of the center core 40a and the side cores 40b and 40c of the magnetic core 40 are shown.

In the first embodiment, as shown in FIG. 6(a), the winding 10a in the substrate coil 10 is formed by overlapping the winding patterns 1a to 8a in the first substrate 1 to the eighth substrate 8. Each of the winding patterns 1a to 8a has a pattern in which a gap is provided at both ends of the arc portion, and in each of the winding patterns 1a to 8a, both ends of the arc portion that sandwich the gap extend in a direction away from the center of the arc portion and are connected to each connection point. The winding patterns other than the first winding pattern 1a have connection points arranged at both ends of each winding pattern so as to sandwich a gap. The first winding pattern 1a has an input terminal 1b and an output terminal 1c separated from the arc portion, and a connection point is arranged at the end of the arc portion opposite the input terminal 1b and the output terminal 1c. In addition, the input terminal 1b of the first winding pattern 1a and the output terminal 1i of the eighth winding pattern 8a are adjacent to each other in a plan view of the winding 10a.

Regarding the connection of the buried through holes in the winding 10a, the connection point 1d on the side closer to the center in the first winding pattern 1a and the connection point 2e on the side farther from the center in the second winding pattern 2a are connected by a buried through hole. Similarly, the connection point 2d on the side closer to the center in the second winding pattern 2a and the connection point 3e on the side farther from the center in the third winding pattern 3a are connected by a buried through hole. The same is true for the connection between the third winding pattern 3a and the fourth winding pattern 4a. The connection point 4d of the fourth winding pattern 4a and the connection point 5e of the fifth winding pattern 5a are connected by a buried through hole in the arc portion of the winding pattern. The connection point 5d on the side farther from the center in the fifth winding pattern 5a and the connection point 6e on the side closer to the center in the sixth winding pattern 6a are connected by a buried through hole. Similarly, the connection point 6d on the side farther from the center in the sixth winding pattern 6a and the connection point 7e on the side closer to the center in the seventh winding pattern 7a are connected by a buried through hole. The same is true for the connection between the seventh winding pattern 7a and the eighth winding pattern 8a. A connection point 8d of the eighth winding pattern 8a passes through the entire substrate from the eighth substrate 8 to the first substrate 1 and is connected to a connection point 1e of the first winding pattern 1a, which is located farther from the center, by a buried through hole.

As shown in FIG. 6(b), in a plan view of the winding 10a, the connection points 1d (2e), 2d (3e), and 3d (4e) are located on the output terminal 1i, and the connection points 5d (6e), 6d (7e), and 7d (8e) are located on the input terminal 1b. The connection point 4d (5e) is tightly packed in the space between the input terminal 1b and the output terminal 1i. The connection point 8d (1e) is located at the farthest position from the center of the winding pattern among all the connection points. These eight pairs of connection points connected to each other by through holes are arranged in a non-overlapping arrangement in a plan view of the winding 10a. In addition, each connection point has an elongated shape extending in a predetermined direction, and is arranged in parallel in a direction perpendicular to the predetermined direction. Here, the predetermined direction refers to the width direction of the gap between the input terminal 1b and the output terminal 1i.

Comparing the plan view of FIG. 6(b) with the plan view of FIG. 1(a), the connection points are efficiently and densely arranged in the plan view of the winding 10a, so the area of each winding pattern is small. In other words, compared to the conventional technology, the substrate coil 10 in Example 1 is easier to achieve a smaller size and lower height. It is also possible to suppress parasitic components due to the connection points.

As described above, the buried through holes connecting the outer winding patterns in the winding 10a are arranged at positions farther from the center of the winding pattern in the plan view of the winding 10a, with the buried through hole connecting the connection point 4d and the connection point 5e at the center. Specifically, the connection point 1d (2e), the connection point 2d (3e), and the connection point 3d (4e) are arranged in this order on the output terminal 1i in the plan view of the winding 10a, so as to approach the center of the winding pattern, and the connection point 5d (6e), the connection point 6d (7e), and the connection point 7d (8e) are arranged in this order on the input terminal 1b in the plan view of the winding 10a, so as to move away from the center of the winding pattern.

Example 2
Next, a second embodiment of the present invention will be described. In the first embodiment, a through hole that connects two winding patterns formed on the substrate at the center in the thickness direction of the winding 10a is placed at a position farther from the center of the winding pattern in the plan view of the winding 10a, that is, an example in which embedded through holes are applied to the substrate coil 10. In the second embodiment, a through hole is applied to the substrate coil, and a through hole that connects a lower winding pattern in the winding is placed at a position farther from the center of the winding pattern in the plan view of the winding.

Figure 7 is a diagram for explaining in detail the connection state of each winding pattern in the substrate coil 101 in Example 2. In this example, a through hole that penetrates the entire multilayer substrate, a so-called through hole, is used.

As shown in the substrate coil 101 of FIG. 7(a), the through-holes move away from the center of the arc of the winding pattern as they move from the first winding pattern 12a on the top surface of the top substrate toward the eighth winding pattern 82a on the bottom surface of the bottom substrate. The through-hole connecting the connection point 82d in the winding pattern of the bottom substrate and the connection point 12e in the winding pattern of the top substrate is located at the farthest position from the center of the arc of the winding pattern in the substrate coil 101. Depending on the order of stacking, the through-holes are located at positions farther or closer to the center of the winding pattern in a plan view. Also, in FIG. 7(a), as in FIG. 1(b), the connection points are indicated by black dots, the through-holes that connect the connection points are indicated by solid lines, and the through-holes that do not connect the connection points are indicated by dotted lines.

As shown in the schematic diagram of the cross section of the substrate coil 101 in FIG. 7(b), both sides of the substrate coil 101 are penetrated by through holes, and each of these through holes is connected to only two specific winding patterns. In FIG. 7(b), the through holes are hatched with diagonal lines, and where they are connected to the winding patterns, the straight lines above and below the winding patterns are not shown, while where they are not connected to the winding patterns, the straight lines above and below the winding patterns are shown. For example, the through hole connecting the second winding pattern 22a and the third winding pattern 32a is not connected to other winding patterns and penetrates both sides of the substrate coil 101. The number of winding patterns is not limited to eight.

The manufacturing process of the substrate coil 101 in FIG. 7 is as follows. First, winding patterns are provided on both sides of the substrate, and new layers are laminated on both sides of the core material to which they are connected by through holes. Next, a winding pattern is formed on the new layer. This process is repeated until the outermost layer is formed, at which point holes are drilled in the layer and plated to form through holes. A winding pattern is further formed on top of that. Finally, a solder resist is attached and the exterior is processed. Note that there may be multiple core materials, and a new layer may be laminated on each core material. Alternatively, the core layers may be bonded together with an insulating layer sandwiched between them.

Figure 8 is a plan view of the winding patterns on each board in Example 2, and of the board coil 101 combined with the magnetic core 401. Figure 8(a) is a plan view of the winding patterns 12a to 82a on the first board 12 to the eighth board 82. Figure 8(b) is a plan view of the winding patterns 12a to 82a stacked in this order and the board coil 101 combined with the magnetic core 401. Note that in Figure 8(b), in order to make the winding patterns 12a to 82a easier to see, only the cross sections of the center core 401a and side cores 401b and 401c of the magnetic core 401 are shown.

In the second embodiment, as shown in FIG. 8(a), the winding 101a in the substrate coil 101 is formed by overlapping the winding patterns 12a to 82a in the first substrate 12 to the eighth substrate 82. Each of the winding patterns 12a to 82a has a pattern in which a gap is provided between both ends of the arc portion corresponding to the winding, and the winding patterns other than the first winding pattern 12a in the outermost layer have connection points arranged at both ends of each winding pattern so as to sandwich the gap. The first winding pattern 12a has an input terminal 12b and an output terminal 12c, and connection points are arranged at the input terminal 12b and the output terminal 12c. In addition, the input terminal 12b of the first winding pattern 12a and the output terminal 12i of the eighth winding pattern 82a are adjacent to each other in a plan view of the winding 101a.

Regarding the connection of the through-holes in the winding 101a, the connection point 12d in the first winding pattern 12a is connected to the connection point 22e on the side closer to the arc portion in the second winding pattern 22a by a through-hole. Next, the connection point 22d on the side farther from the center in the second winding pattern 22a is connected to the connection point 32e on the side closer to the center in the third winding pattern 32a by a through-hole. Similarly, the connection point 32d on the side farther from the center in the third winding pattern 32a is connected to the connection point 42e on the side closer to the center in the fourth winding pattern 42a by a through-hole. Thereafter, by repeating this structure, for the through-hole at the bottom of the winding 101a, the connection point 82d on the side farther from the center in the eighth winding pattern 82a is connected to the connection point 12e on the side farther from the center in the first winding pattern 12a by a through-hole through the entire substrate from the eighth substrate 82 to the first substrate 12.

8(b), the connection points 12d (22e), 22d (32e), 32d (42e), 42d (52e), 52d (62e), 62d (72e), and 72d (82e) are located in this order near the center of the winding pattern in a plan view of the winding 101a, and are closely packed in the space between the input terminal 12b and the output terminal 12i along the radial direction of the winding pattern. This makes it possible to increase the winding efficiency of each winding pattern while suppressing the influence of the magnetic field generated by the current flowing through the connection points on the winding 101a. These eight connection points are arranged in a non-overlapping arrangement in a plan view of the winding 101a. Each connection point has an elongated shape extending in a predetermined direction, and is arranged in parallel in a direction perpendicular to the predetermined direction. Here, the predetermined direction refers to the width direction of the space between the input terminal 12b and the output terminal 12i.

Regarding the arrangement of the through holes, the arrangement of the penetrating through holes shown in Example 2 may be applied to the buried through holes shown in Example 1.

Example 3
Next, a third embodiment of the present invention will be described. In the first embodiment, an example in which embedded through holes are applied to substrate coil 10, and in the second embodiment, an example in which penetrating through holes are applied to substrate coil 101 will be described. In the third embodiment, an example in which both embedded through holes and penetrating through holes are applied to a substrate coil will be described.

Figure 9 is a diagram for explaining in detail the connection state of each winding pattern in the substrate coil 102 in Example 3. In this example, embedded through holes and penetrating through holes are used.

As shown in the substrate coil 102 in FIG. 9(a), the first winding pattern 13a and the second winding pattern 23a, the third winding pattern 33a and the fourth winding pattern 43a, the fifth winding pattern 53a and the sixth winding pattern 63a, and the seventh winding pattern 73a and the eighth winding pattern 83a are each 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 the substrate coil 102.

Compared to the embedded through holes, the through holes connect the winding patterns at a position farther from the arc portion of the winding pattern. The embedded through holes are located at almost the same position in the substrate coil 102 when viewed from above. As for the through holes, the through hole connecting the fourth winding pattern 43a and the fifth winding pattern 53a is located closest to the arc portion of the winding pattern, followed by the through hole connecting the sixth winding pattern 63a and the seventh winding pattern 73a, the through hole connecting the second winding pattern 23a and the third winding pattern 33a, and the through hole connecting the first winding pattern 13a and the eighth winding pattern 83a, in that order, which are located closest to the arc portion of the winding pattern. Also, in FIG. 9(a), as in FIG. 1(b), the connection points are indicated by black dots, the embedded through holes and through holes that connect the connection points are indicated by solid lines, and the through holes that do not connect the connection points are indicated by dotted lines.

As shown in the schematic diagram of the cross section of the substrate coil 102 in FIG. 9(b), both sides of the substrate coil 102 are penetrated by four through holes, and each of these through holes is connected to only two specific winding patterns. In FIG. 9(b), the through holes are hatched with diagonal lines, and the upper and lower boundaries of the winding patterns are not clearly indicated at the points where they are connected to the winding patterns, and the upper and lower boundaries of the winding patterns are clearly indicated at the points where they are not connected to the winding patterns. For example, the through hole connecting the fourth winding pattern 43a and the fifth winding pattern 53a is not connected to other winding patterns and penetrates both sides of the substrate coil 102. The number of winding patterns is not limited to eight. In addition, the manufacturing process of the substrate coil 102 is a combination of the manufacturing process of the substrate coil 10 in FIG. 4, which uses only embedded through holes as through holes, and the manufacturing process of the substrate coil 101 in FIG. 7, which uses only through holes as through holes.

Example 4
Next, a fourth embodiment of the present invention will be described. In the first embodiment, the transformer 30 is described that includes the substrate coils 10 and 20 in which only a portion of the winding pattern is covered by the magnetic core 40. In the fourth embodiment, however, a transformer is described that includes a substrate coil in which the winding pattern is not covered by the magnetic core, and a transformer in which a path core structure is applied between two types of coils.

FIG. 10 is a cross-sectional view of a transformer in Example 4. FIG. 10(a) is a cross-sectional view of a transformer 303 including a substrate coil 103 and a second substrate coil 203 whose winding patterns (not shown) are not covered by a magnetic core 403. The magnetic core 403 is positioned so as to be surrounded by the winding patterns of the substrates. In the configuration of FIG. 10(a), the connection points (not shown) on the winding patterns are not covered by the magnetic core 403. Therefore, it is possible to avoid the drawbacks of disturbance in the magnetic field generated by the current flowing on the winding patterns and the drawbacks of uneven amounts of magnetic fields passing between side cores (not shown), and to increase the degree of freedom in arranging the connection points.

Figure 10(b) is a cross-sectional view of a transformer 304 in which a path core structure is applied between the substrate coil 104 and the second substrate coil 204. When the resonator L is externally attached to improve the operating efficiency of the transformer, the mounting area increases when the transformer and the resonator L are arranged horizontally, and when they are stacked vertically, a shield is required, which causes the inconvenience of increasing the height. Therefore, in either of the above cases, it is difficult to make the transformer small and low-profile. In the configuration of Figure 10(b), by inserting a magnetic core 404 between the substrate coil 104 and the second substrate coil 204 and applying a path core structure, it is possible to induce resonance in the substrate coil 104 and the second substrate coil 204 while making the transformer 304 small and low-profile.

Furthermore, like the transformer 30 of Example 1, the number of turns of the substrate coils 103, 104 and the number of turns of the second substrate coils 203, 204 may be the same or different, and a normal wound coil may be used instead of the second substrate coils 203, 204.

In the following, the components 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 components of the present invention with the configurations of the embodiments.
<Invention 1>
A substrate coil (10, 20) formed by laminating winding patterns (1a to 8a) provided on a plurality of layers (1 to 8) constituting a multilayer substrate and electrically connecting the winding patterns at connection portions (1d to 8d, 1e to 8e),
the connection portions of the winding pattern have an elongated shape extending in a predetermined direction in a plan view, and the connection portions are connected to each other by through holes that are conductive in a direction perpendicular to the plane of the winding pattern,
Among the winding patterns provided on the plurality of layers, a pair of connection parts of two overlapping winding patterns to be connected to each other and a pair of connection parts of two winding patterns to be connected next are formed so as not to overlap in a plan view and to be aligned in a direction perpendicular to the predetermined direction.
Substrate coil.

1-8: substrate 1a-8a: winding pattern 10a: winding 1b: input terminal 1c: output terminal 1d-8d: connection point 1e-8e: connection point 1f-8f: opening 1g-8g: opening 1h-8h: opening 1i: output terminal 10, 20: substrate coil 30: transformer 40: magnetic core 40a: center core 40b, 40c: side core

Claims (10)

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 portions of the winding pattern have an elongated shape extending in a predetermined direction in a plan view, and the connection portions are connected to each other by through holes that are conductive in a direction perpendicular to the plane of the winding pattern,
among the winding patterns provided on the plurality of layers, a pair of connection portions of two overlapping winding patterns connected to each other and a pair of connection portions of two winding patterns connected next to each other are formed so as not to overlap in a plan view and to be aligned in a direction perpendicular to the predetermined direction ,
the through hole is a buried through hole penetrating only a part of the layers of the multilayer board,
In the multilayer board, a pair of connection parts of two outer winding patterns is disposed at a position farther from the center of the winding patterns in a plan view than a pair of connection parts of two inner winding patterns .
Substrate coil. the winding pattern is an arc-shaped single winding pattern,
2. The substrate coil according to claim 1, wherein the predetermined direction is a width direction of a gap between both ends of the winding pattern. The substrate coil according to claim 1 or 2, characterized in that the through holes are arranged in parallel in one or two rows in the connection portion in the direction in which the connection portion extends. The substrate coil according to any one of claims 1 to 3, characterized in that the connection portion in the winding pattern is connected outside the winding pattern in a plan view. the through hole is a through hole penetrating the multilayer board,
A substrate coil as described in any one of claims 1 to 4, characterized in that in the multilayer substrate, pairs of connection parts of each winding pattern are positioned farther or closer to the center of the winding pattern in a planar view depending on the order in which they are stacked. a magnetic core disposed so as to cover a portion of the winding pattern in a plan view;
The substrate coil according to claim 1 , wherein the connection portion is disposed in a portion where the magnetic core is not provided in a plan view. A transformer in which multiple coils are arranged in a stacked manner, a current is input to one coil, and an induced current flows through the other coils,
The magnetic coil further includes a magnetic core disposed to pass through the center of the coils.
At least a part of the plurality of coils is a substrate coil according to any one of claims 1 to 4.
transformer. 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. 8. The transformer according to claim 7 , wherein the magnetic core is a rod core having a rod shape penetrating through the center of the plurality of coils. the magnetic core is disposed so as to cover a portion of the plurality of coils in a plan view,
9. The transformer according to claim 7 , wherein the connection portion is disposed in a portion where the magnetic core is not provided in a plan view.

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