Printed wiring board and coil assembly
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Patents
- Current Assignee / Owner
- SUMITOMO ELECTRIC PRINTED CIRCUITS INC
- Filing Date
- 2022-12-26
- Publication Date
- 2026-08-01
AI Technical Summary
Existing printed wiring boards result in coil devices with uniform thickness, leading to assembly challenges due to increased size and complexity.
A printed wiring board design with varying parts and coil configurations that allow for partial reduction in thickness by overlapping and separating coil portions upon bending, enhancing assembly properties.
The design achieves a partially reduced thickness in the coil device, improving assembly efficiency and allowing space for electronic components, while maintaining electrical connections and reducing damage to connecting portions.
Smart Images
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Abstract
Description
Printed wiring board and coil assembly This disclosure relates to a printed wiring board and a coil device. This application claims priority based on Japanese Patent Application No. 2021-212226, filed on December 27, 2021. The entire contents of that Japanese Patent Application are incorporated herein by reference. For example, Japanese Patent Application Publication No. 2020-181852 (Patent Document 1) describes a printed wiring board. The printed wiring board described in Patent Document 1 includes a flexible substrate, a first coil wiring, and a second coil wiring. The flexible substrate has a first surface and a second surface. The second surface is the opposite surface of the first surface. The flexible substrate has a plurality of portions when viewed from above. Each of the plurality of portions of the flexible substrate is arranged along a first direction. The first direction is the longitudinal direction of the flexible substrate when viewed from above. Two adjacent boundaries of the plurality of portions of the flexible substrate are along a second direction. The second direction is a direction orthogonal to the first direction. The first wiring is disposed on the first surface and has a plurality of first coils. Each of the plurality of first coils is a portion of the first wiring wound in a spiral shape when viewed from above. Each of the plurality of first coils is disposed on each of a plurality of portions of the flexible substrate. The second wiring is disposed on the second surface and has a plurality of second coils. Each of the plurality of second coils is a portion of the second wiring wound in a spiral shape when viewed from above. Each of the plurality of second coils is disposed in a plurality of portions of the flexible substrate. A flexible substrate is bent along two adjacent boundaries of a plurality of portions. This allows for the alternating deposition of a plurality of first and second coils disposed within one of the plurality of portions of the flexible substrate. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 2020-181852 The printed wiring board disclosed herein comprises: a base film having a first main surface and a second main surface; a first wiring disposed on the first main surface; and a second wiring disposed on the second main surface. The base film has a first portion and a second portion. The first portion and the second portion are arranged along the length direction of the base film in plan view, i.e., a first direction. The boundary between the first portion and the second portion, i.e., the first boundary, is perpendicular to the first direction in plan view along a second direction. The first wiring comprises: a first coil portion located in the first portion and wound into a spiral shape in plan view; and a second coil portion located in the second portion and wound into a spiral shape in plan view. When the base film is bent along the first boundary in plan view such that the first coil portion overlaps the second coil portion, the first portion is arranged such that it partially overlaps the second portion in plan view. [Problem to be Solved by this Disclosure] In the printed circuit board described in Patent Document 1, each of the plurality of portions of the flexible substrate has the same shape when viewed from above. Therefore, the thickness of the coil device obtained from the printed circuit board described in Patent Document 1 increases regardless of the location. As a result, the coil device has room for improvement in assemblability. This invention was made in view of the problems of the prior art as described above. More specifically, this disclosure provides a printed wiring board for a coil device that allows for a reduction in thickness during assembly. [Effects of this disclosure] According to the printed wiring board disclosed herein, a coil device with reduced thickness during assembly can be obtained. [Explanation of the Implementation Forms of this Disclosure] First, the implementation forms of this disclosure are listed and explained. (1) An embodiment of a printed wiring board includes: a base film having a first main surface and a second main surface; a first wiring disposed on the first main surface; and a second wiring disposed on the second main surface. The base film has a first portion and a second portion. The first portion and the second portion are arranged along the length direction of the base film in plan view, i.e., a first direction. The boundary between the first portion and the second portion, i.e., the first boundary, is perpendicular to the first direction in plan view along a second direction. The first wiring has: a first coil portion located in the first portion and wound into a spiral shape in plan view; and a second coil portion located in the second portion and wound into a spiral shape in plan view. When the base film is bent along the first boundary in plan view such that the first coil portion overlaps the second coil portion, the first portion is arranged such that it partially overlaps the second portion in plan view. Based on the printed wiring board of (1) above, a coil device with reduced thickness during assembly can be obtained. (2) In the printed wiring board of (1) above, the second wiring may also have: a third coil portion located in the first portion and wound into a spiral shape when viewed from above; and a fourth coil portion located in the second portion and wound into a spiral shape when viewed from above. The third coil portion and the fourth coil portion may also overlap the first coil portion and the second coil portion when viewed from above, respectively. (3) In the printed wiring board of (2) above, the base film may further have a third portion. The first portion may also be sandwiched between the second and third portions in the first direction. The boundary between the first and third portions, i.e. the second boundary, may also be along the second direction. The first wiring may also have: a fifth coil portion located in the first portion and wound into a spiral shape in plan view; and a sixth coil portion located in the third portion and wound into a spiral shape in plan view. The second wiring may also have: a seventh coil portion located in the first portion and wound into a spiral shape in plan view; and an eighth coil portion located in the third portion and wound into a spiral shape in plan view. The seventh and eighth coil portions may also overlap the fifth and sixth coil portions in plan view, respectively. When the base film is bent along the first boundary in a top view with the first coil portion overlapping the second coil portion, and when the base film is bent along the second boundary in a top view with the fifth coil portion overlapping the sixth coil portion, the second part can also be arranged separately from the third part. (4) One embodiment of the coil device comprises: a base film having a first main surface and a second main surface; a first wiring disposed on the first main surface; and a second wiring disposed on the second main surface. The base film has a first portion and a second portion. The first portion and the second portion, in a state before bending, are arranged along the length direction of the base film as viewed from above, i.e., a first direction. The boundary between the first portion and the second portion, i.e., the first boundary, is orthogonal to the first direction as viewed from above in a second direction. The first wiring comprises: a first coil portion located in the first portion and wound into a spiral shape as viewed from above; and a second coil portion located in the second portion and wound into a spiral shape as viewed from above. The base film is bent along the first boundary as viewed from above, with the first coil portion overlapping the second coil portion. The first portion, in a state after bending, partially overlaps the second portion as viewed from above. According to the coil device described in (4) above, since the thickness of the non-overlapping portion of the first part and the second part is less than the thickness of the overlapping portion of the first part and the second part, the assemblability is improved. (5) In the coil device of (4) above, the second wiring may also include: a third coil portion located in the first portion and wound into a spiral shape in plan view; and a fourth coil portion located in the second portion and wound into a spiral shape in plan view. The third coil portion and the fourth coil portion may also overlap the first coil portion and the second coil portion in plan view, respectively. (6) In the coil device described in (5) above, the first main surface of the first part may also partially face the first main surface of the second part when the bottom film is bent. The first wiring may further have a first connecting part that connects the first coil part and the second coil part. The first connecting part may also extend in a manner that crosses the first boundary. According to the coil device described in (6) above, since the first connecting part is located inside the bent bottom film, the first connecting part is not easily damaged. (7) The coil device described in (4) above may further include electronic components. The second main surface located in the first part may also be partially facing the second main surface located in the second part when the base film is bent. The second part may also be separated from the first part when the base film is bent. The electronic components may also be disposed between the first part and the second part and connected to the second wiring when the base film is bent. According to the coil device described in (7) above, even when the base film is bent, space is ensured for placing electronic components between the first and second parts. (8) In the coil device of (5) above, the base film may further have a third portion. The first portion may also be sandwiched between the second and third portions in the first direction in the state before the base film is bent. The boundary between the first and third portions, i.e. the second boundary, may also be along the second direction. The first wiring may also have: a fifth coil portion located in the first portion and wound into a spiral shape in plan view; and a sixth coil portion located in the third portion and wound into a spiral shape in plan view. The second wiring may also have: a seventh coil portion located in the first portion and wound into a spiral shape in plan view; and an eighth coil portion located in the third portion and wound into a spiral shape in plan view. The seventh and eighth coil portions may also overlap the fifth and sixth coil portions in plan view, respectively. The base film can also be bent along the first boundary in a top view, with the first coil portion overlapping the second coil portion, and bent along the second boundary in a top view, with the fifth coil portion overlapping the sixth coil portion. The second part can also be separated from the third part in the bent state of the base film. (9) In the printed wiring board of (8) above, the first main surface of the first part can also partially face the first main surface of the third part when the base film is bent. The first wiring can also have a second connecting part that connects the fifth coil part and the sixth coil part. The second connecting part can also extend in a manner that crosses the second boundary. When using the coil device described above (9), since the second connection part is located inside the bent bottom film, the second connection part is not easily damaged. (10) The coil device described in (8) may further include: an electronic component, which is disposed between the second part and the third part in the state after the base film is bent. According to the coil device described in (10) above, there is a portion with reduced thickness between the second and third portions, where electronic components can be disposed. [Details of the Embodiments of This Disclosure] The details of the embodiments of this disclosure will be explained with reference to the drawings. In the following drawings, the same or equivalent parts will be labeled with the same reference number, and the explanations will not be repeated. (First Embodiment) The printed wiring board and the coil device of the first embodiment will be described. Hereinafter, the printed wiring board of the first embodiment will be referred to as printed wiring board 100, and the coil device of the first embodiment will be referred to as coil device 200. <Composition of Printed Wiring Board 100> The following describes the composition of the printed wiring board 100. Figure 1 is a top view of the printed wiring board 100. Figure 2 is a bottom view of the printed wiring board 100. Figure 3A is a cross-sectional view along line IIIA-IIIA in Figure 1. Figure 3B is a partially enlarged view of Figure 3A. The protective layer 50 is omitted in Figure 1, and the protective layer 60 is omitted in Figure 2. As shown in Figures 1, 2, 3A, and 3B, the printed wiring board 100 has a base film 10, a first wiring 20, and a second wiring 30. The substrate 10 has a first main surface 10a and a second main surface 10b. The first main surface 10a and the second main surface 10b are end faces in the thickness direction of the substrate 10. The second main surface 10b is the opposite surface of the first main surface 10a. The substrate 10 is formed of a flexible, electrically insulating resin material. For example, the substrate 10 is formed of polyimide, fluororesin, etc. The length direction of the substrate 10 as viewed from above is defined as the first direction DR1. The width direction of the substrate 10 as viewed from above is defined as the second direction DR2. The second direction DR2 is orthogonal to the first direction DR1. Furthermore, the first direction DR1 and the second direction DR2 are orthogonal to the thickness direction of the substrate 10. In addition, the substrate 10, as viewed from above, is composed of a first side and a second side that are parallel to each other, and a third side and a fourth side that are parallel to each other and orthogonal to the first side (second side). The first side and the second side are longer than the third side and the fourth side. The direction from the third side to the fourth side is the length direction of the substrate 10 as viewed from above (the first direction DR1), and the direction from the first side to the second side is the width direction of the substrate 10 as viewed from above (the second direction DR2). The base film 10 has a first portion 11 and a second portion 12. The base film 10 may also have a third portion 13. The first portion 11, the second portion 12, and the third portion 13 are arranged along a first direction DR1. The first portion 11 is sandwiched between the second portion 12 and the third portion 13 along the first direction DR1. The boundaries between the first portion 11 and the second portion 12 (refer to the dashed lines in Figures 1 and 2) and between the first portion 11 and the third portion 13 (refer to the dashed lines in Figures 1 and 2) are along a second direction DR2. That is, the first portion 11, the second portion 12, and the third portion 13 are rectangular in top view. The width of the first portion 11 along the first direction DR1 is greater than the width of the second portion 12 and the width of the third portion 13 along the first direction DR1. The first wiring 20 is disposed on the first main surface 10a. The first wiring 20 has a first coil portion 21, a second coil portion 22, and a first connecting portion 23. The first coil portion 21 and the second coil portion 22 are wound into a spiral shape when viewed from above. The first coil portion 21 and the second coil portion 22 are respectively located in the first part 11 and the second part 12. More specifically, the first coil portion 21 is disposed near the four corners of the first part 11, which is located next to the second part 12, when viewed from above. The second coil portion 22 is disposed opposite to the first coil portion 21, across the boundary between the first part 11 and the second part 12 when viewed from above. One end of the first coil portion 21 and the other end are located at the innermost and outermost circumferences of the first coil portion 21, respectively. One end of the second coil portion 22 and the other end are located at the innermost and outermost circumferences of the second coil portion 22, respectively. The first connecting portion 23 connects the other end of the first coil portion 21 to the other end of the second coil portion 22. The first connecting portion 23 extends in a manner that intersects the boundary between the first portion 11 and the second portion 12. The first connecting portion 23 extends, for example, along the first direction DR1. The second wiring 30 is disposed on the second main surface 10b. The second wiring 30 has a third coil portion 31 and a fourth coil portion 32. The third coil portion 31 and the fourth coil portion 32 are wound into a spiral shape when viewed from above. The third coil portion 31 and the fourth coil portion 32 are located in the first part 11 and the second part 12, respectively. More specifically, the third coil portion 31 is disposed near the four corners of the first part 11, which is located next to the second part 12, when viewed from above. The fourth coil portion 32 is disposed opposite to the third coil portion 31, separated by the boundary between the first part 11 and the second part 12, when viewed from above. The third coil portion 31 overlaps with the first coil portion 21 when viewed from above. The fourth coil portion 32 overlaps with the second coil portion 22 when viewed from above. One end of the third coil portion 31 and the other end are located at the innermost and outermost circumferences of the third coil portion 31, respectively. One end of the fourth coil portion 32 and the other end are located at the innermost and outermost circumferences of the fourth coil portion 32, respectively. The first coil portion 20 further includes a fifth coil portion 24, a sixth coil portion 25, and a second connecting portion 26. The fifth coil portion 24 and the sixth coil portion 25 are wound in a spiral shape when viewed from above. The fifth coil portion 24 and the sixth coil portion 25 are located in the first part 11 and the third part 13, respectively. More specifically, the fifth coil portion 24, when viewed from above, is positioned near the four corners of the first part 11 located on the side of the third part 13. The sixth coil portion 25, when viewed from above, is positioned opposite the fifth coil portion 24, separated by the boundary between the first part 11 and the third part 13. One end of the fifth coil portion 24 and the other end are located at the innermost and outermost circumferences of the fifth coil portion 24, respectively. One end of the sixth coil portion 25 and the other end are located at the innermost and outermost circumferences of the sixth coil portion 25, respectively. The second connecting portion 26 connects the other end of the fifth coil portion 24 to the other end of the sixth coil portion 25. The second connecting portion 26 extends in a manner that intersects the boundary between the first portion 11 and the third portion 13. The second connecting portion 26 extends, for example, along the first direction DR1. The second wiring 30 further includes a seventh coil portion 33 and an eighth coil portion 34. The seventh coil portion 33 and the eighth coil portion 34 are wound in a spiral shape when viewed from above. The seventh coil portion 33 and the eighth coil portion 34 are located in the first part 11 and the third part 13, respectively. More specifically, the seventh coil portion 33, when viewed from above, is positioned near the four corners of the first part 11 located on the side of the third part 13. The eighth coil portion 34, when viewed from above, is positioned opposite the seventh coil portion 33, separated by the boundary between the first part 11 and the third part 13. The seventh coil portion 33 overlaps with the fifth coil portion 24 when viewed from above. The eighth coil portion 34 overlaps with the sixth coil portion 25 when viewed from above. One end of the 7th coil portion 33 and the other end are located at the innermost and outermost circumferences of the 7th coil portion 33, respectively. One end of the 8th coil portion 34 and the other end are located at the innermost and outermost circumferences of the 8th coil portion 34, respectively. One end of the first coil portion 21 becomes pad 27a. The other end of the second coil portion 22 becomes pad 27b. One end of the third coil portion 31 becomes pad 35a. Pad 35a overlaps with pad 27a in top view. The other end of the third coil portion 31 becomes pad 35b. One end of the fourth coil portion 32 becomes pad 35c. Pad 35c overlaps with pad 27b in top view. The other end of the fourth coil portion 32 becomes pad 35d. One end of the 5th coil portion 24 becomes pad 27c. The other end of the 6th coil portion 25 becomes pad 27d. One end of the 7th coil portion 33 becomes pad 35e. Pad 35e overlaps with pad 27c in top view. The other end of the 7th coil portion 33 becomes pad 35f. One end of the 8th coil portion 34 becomes pad 35g. Pad 35g overlaps with pad 27d in top view. The other end of the 8th coil portion 34 becomes pad 35h. The first wiring 20 and the second wiring 30 are formed, for example, by a semi-additive process. The first wiring 20 and the second wiring 30 have a seed layer 41 and an electroplated layer 42. The seed layer 41 has a first layer 41a and a second layer 41b. The first layer 41a is disposed on the main surfaces (first main surface 10a, second main surface 10b) of the substrate 10. The second layer 41b is disposed on the first layer 41a. The first layer 41a is formed, for example, of a nickel-chromium alloy. The second layer 41b is formed, for example, of copper. On the base film 10, through-holes 10c are formed at the following locations when viewed from above: overlapping pads 27a and 35a, overlapping pads 27b and 35c, overlapping pads 27c and 35e, and overlapping pads 27d and 35g. The through-holes 10c penetrate the base film 10 along its thickness direction. A second layer 41b is also disposed on the inner wall surface of the through-holes 10c. An electroplated layer 42 is disposed on a seed layer 41 (second layer 41b). The electroplated layer 42 is embedded in a through-hole 10c. Through the electroplated layer 42 embedded in the through-hole 10c, the first coil portion 21 and the third coil portion 31 are electrically connected, and the second coil portion 22 and the fourth coil portion 32 are electrically connected. Through the electroplated layer 42 embedded in the through-hole 10c, the fifth coil portion 24 and the seventh coil portion 33 are electrically connected, and the sixth coil portion 25 and the eighth coil portion 34 are electrically connected. The electroplated layer 42 is formed by electroplating. The electroplated layer 42 is formed, for example, of copper. The above description uses the case where the first wiring 20 and the second wiring 30 are formed by a semi-additive method as an example, but the first wiring 20 and the second wiring 30 can also be formed by a subtractive method. The printed wiring board 100 further has a protective layer 50 and a protective layer 60. The protective layer 50 has a first layer 51 and a second layer 52. The protective layer 60 has a first layer 61 and a second layer 62. A first layer 51 is disposed on a first main surface 10a such that it covers the first wiring 20. The first layer 51 is formed, for example, by an adhesive. A second layer 52 is disposed on the first layer 51. The second layer 52 is formed, for example, by polyimide. The first layer 61 is disposed on the second main surface 10b in such a way as to cover the second wiring 30. The first layer 61 is formed, for example, by an adhesive. The second layer 62 is disposed on the first layer 61. The second layer 62 is formed, for example, by polyimide. Furthermore, the protective layer 60 may be removed at the overlapping locations near the boundaries of the first portion 11 and the second portion 12, and near the boundaries of the first portion 11 and the third portion, when viewed from above. <Composition of Coil Device 200> The composition of coil device 200 will be described below. Figure 4 is a cross-sectional view of the coil assembly 200. As shown in Figure 4, the coil assembly 200 has a printed wiring board 100 and a bonding sheet 70. In the coil assembly 200, the base film 10 is bent such that the second coil portion 22 overlaps the first coil portion 21 in top view. For example, the base film 10 is bent such that the portion located on the first main surface 10a of the second portion 12 faces the portion located on the first main surface 10a of the first portion 11. Furthermore, in the coil assembly 200, the base film 10 is bent such that the sixth coil portion 25 overlaps the fifth coil portion 24 in top view. For example, the base film 10 is bent such that the portion located on the first main surface 10a of the third portion 13 faces the portion located on the first main surface 10a of the first portion 11. As described above, the first coil portion 21 overlaps with the third coil portion 31 in a top view, and the second coil portion 22 overlaps with the fourth coil portion 32 in a top view. Also, as described above, the fifth coil portion 24 overlaps with the seventh coil portion 33 in a top view, and the sixth coil portion 25 overlaps with the eighth coil portion 34 in a top view. Therefore, when the base film 10 is bent as described above, the first coil portion 21, the second coil portion 22, the third coil portion 31, and the fourth coil portion 32 overlap to form one coil in a top view, and the fifth coil portion 24, the sixth coil portion 25, the seventh coil portion 33, and the eighth coil portion 34 overlap to form one coil in a top view. Additionally, the coil composed of the first coil section 21, the second coil section 22, the third coil section 31 and the fourth coil section 32 generates a magnetic field by the flow of current from pads 35b and 35d, and the coil composed of the fifth coil section 24, the sixth coil section 25, the seventh coil section 33 and the eighth coil section 34 generates a magnetic field by the flow of current from pads 35f and 35h. With the base film 10 bent as described above, the second portion 12 overlaps the first portion 11 in plan view, and the third portion 13 overlaps the first portion 11 in plan view. With the base film 10 bent as described above, the second portion 12 and the third portion 13 are spaced apart from each other in the first direction DR1. From another perspective, in the coil device 200, the thickness of the portion of the first portion 11 that does not overlap with either the second portion 12 or the third portion 13 is less than the thickness of the portion of the first portion 11 that overlaps with either the second portion 12 or the third portion 13. Although not illustrated, electronic components can be arranged in the space between the second portion 12 and the third portion 13 with the base film 10 bent as described above. These electronic components may be, for example, magnetic sensors. With the base film 10 bent as described above, the adhesive sheet 70 is disposed between the portion of the protective layer 50 on the first portion 11 and the portion of the protective layer 50 on the second portion 12, and between the portion of the protective layer 50 on the first portion 11 and the portion of the protective layer 50 on the third portion 13. In this way, the base film 10 maintains its bent state as described above. The adhesive sheet 70 is formed, for example, by an adhesive. <Effects of the printed wiring board 100 and the coil device 200> The coil device 200 has a portion with increased thickness (the portion where the first part 11 overlaps with the second part 12, and the portion where the first part 11 overlaps with the third part 13) and a portion with decreased thickness (the portion where the first part 11 does not overlap with either the second part 12 or the third part 13). The device (actuator, etc.) assembling the coil assembly 200 has electronic components, for example. Since the coil assembly 200 can be assembled to the actuator, etc., in a way that the electronic components are arranged in a part with reduced thickness, the assemblability is improved. In the coil device 200, since the base film 10 is bent such that the portion located on the first main surface 10a of the first part 11 faces the portion located on the first main surface 10a of the second part 12, and the portion located on the first main surface 10a of the first part 11 faces the portion located on the first main surface 10a of the third part 13, the first connecting portion 23 and the second connecting portion 26 are located inside the bent base film 10. Therefore, tensile stress is less likely to act on the first connecting portion 23 and the second connecting portion 26, and cracking at the first connecting portion 23 and the second connecting portion 26 can be suppressed. Furthermore, as described above, when the base film 10 is bent, the radius of curvature of the first main surface 10a is smaller than the radius of curvature of the neutral axis. Thus, the position where the radius of curvature is smaller than the neutral axis is inside the bent base film 10. The coil assembly 200 can be assembled using a printed wiring board 100 and a bent base film 10. Therefore, a coil assembly with a reduced thickness can be obtained using the printed wiring board 100. In the coil assembly 200, since a single coil is formed by stacking multiple coil sections, the total number of turns of that single coil increases, and the thrust is increased. From another perspective, even if the width of the wiring in each coil section is increased to reduce the resistance, the thrust can be maintained or increased. (Second Embodiment) The coil device of the second embodiment will be described. Hereinafter, the coil device of the second embodiment will be referred to as coil device 200A. Here, the differences from coil device 200A will be mainly explained, and the explanations will not be repeated. <Composition of Coil Device 200A> The composition of coil device 200A will be described below. Figure 5 is a cross-sectional view of the coil device 200A. As shown in Figure 5, the coil device 200A has a printed wiring board 100, a bonding sheet 71, and a bonding sheet 72. In the printed wiring board 100 of the coil device 200A, the first wiring 20 does not have a fifth coil portion 24 and a first connecting portion 23, and the second wiring 30 does not have a third coil portion 31. Furthermore, in the printed wiring board 100 of the coil device 200A, the second wiring 30 has a third connecting portion 36. Additionally, the third connecting portion 36, when viewed from above, extends along the first direction DR1, intersecting the boundary between the first portion 11 and the second portion 12. In the coil device 200A, the base film 10 is bent such that the portion located on the second main surface 10b of the first part 11 faces the portion located on the second main surface 10b of the second part 12, and the portion located on the first main surface 10a of the first part 11 faces the portion located on the first main surface 10a of the third part 13. In the coil device 200A, the base film 10 is maintained in the bent state described above by the adhesive piece 71 disposed between the portion of the protective layer 60 on the first part 11 and the protective layer 60 on the second part 12, and the adhesive piece 72 disposed between the portion of the protective layer 50 on the first part 11 and the protective layer 50 on the third part 13. The coil device 200A includes electronic components 81 and 82. Electronic components 81 and 82 are respectively disposed between the first part 11 and the second part 12, and between the first part 11 and the third part 13, with the base film 10 bent as described above. Electronic component 81 is electrically connected to pads 37a and 37b disposed on the second main surface 10b, and electronic component 82 is electrically connected to pads 28a and 28b disposed on the first main surface 10a. Pads 28a and 28b constitute a portion of the first wiring 20, and pads 37a and 37b constitute a portion of the second wiring 30. Furthermore, the protective layer 60 and the bonding pad 71 are open in a manner that exposes pads 37a and 37b, and the protective layer 50 and the bonding pad 71 are open in a manner that exposes pads 28a and 28b. <Effects of Coil Device 200A> The effects of coil device 200A will be explained below. In the coil device 200, since electronic components 81 and 82 can be respectively arranged between the first part 11 and the second part 12, and between the first part 11 and the third part 13, they can be installed in a state where electronic components 81 and 82 are hidden from the outside. It should be understood that the embodiments disclosed herein are illustrative and not restrictive. The scope of this invention is not limited to the embodiments described above, but is indicated by the scope of the patent application, and is intended to include the same meaning as the scope of the patent application and all modifications within that scope. 10: Bottom film 10a: First main surface 10b: Second main surface 10c: Through hole 11: First part 12: Second part 13: Third part 20: First wiring 21: First coil section 22: Second coil section 23: First connecting part 24: Fifth coil section 25: Sixth coil section 26: Second connecting part 27a, 27b, 27c, 27d: Pads 28a, 28b: Pads 30: Second wiring 31: Third coil section 32: Fourth coil section 33: Seventh coil section 34: Eighth coil section 35a 35b, 35c, 35d, 35e, 35f, 35g, 35h: Pads; 36: Third Connection; 37a: Pads; 37b: Pads; 41: Seed Layer; 41a: First Layer; 41b: Second Layer; 42: Electroplated Coating; 50: Protective Layer; 51: First Layer; 52: Second Layer; 60: Protective Layer; 61: First Layer; 62: Second Layer; 70, 71, 72: Adhesive Sheets; 81, 82: Electronic Components; 100: Printed Wiring Board; 200, 200A: Coil Assembly; DR1: First Direction; DR2: Second Direction Figure 1 is a top view of the printed circuit board 100. Figure 2 is a bottom view of the printed circuit board 100. Figure 3A is a sectional view of section IIIA-IIIA in Figure 1. Figure 3B is a partially enlarged view of Figure 3A. Figure 4 is a sectional view of the coil device 200. Figure 5 is a sectional view of the coil device 200A. 10: Bottom film 10a: 1st main side 10b: 2nd main side 10c: Through hole 21: First coil section 22: Second coil section 23: First connecting part 24: Fifth coil section 25: 6th coil section 26: Second connecting part 27a, 27b, 27c, 27d: Pads 31: Third coil section 32: Fourth coil section 33: 7th coil section 34: 8th coil section 35a, 35b, 35c, 35d, 35e, 35f, 35g, 35h: Pads 50: Protective layer 51: Level 1 52: Level 2 60: Protective layer 61: First Floor 62: Level 2 100: Printed Wiring Board DR1: Direction 1
Claims
1. A printed wiring board, comprising: a base film having a first main surface and a second main surface; a first wiring disposed on the first main surface; and a second wiring disposed on the second main surface; wherein the base film has a first portion and a second portion; the first portion and the second portion are arranged along the length direction of the base film in plan view, i.e., a first direction; the boundary between the first portion and the second portion, i.e., a first boundary, is along a second direction orthogonal to the first direction in plan view; the first wiring includes: a first coil portion located in the first portion and wound into a spiral shape in plan view; and a second coil portion located in the second portion and wound into a spiral shape in plan view; the width of the first portion in the first direction is greater than the width of the second portion in the first direction. When the base film is bent along the first boundary in a top view such that the first coil portion overlaps the second coil portion, the first portion overlaps the second portion in a top view.
2. The printed wiring board of claim 1, wherein the second wiring comprises: a third coil portion located in the first portion and wound in a spiral shape in plan view; and a fourth coil portion located in the second portion and wound in a spiral shape in plan view; and the third coil portion and the fourth coil portion respectively overlapping the first coil portion and the second coil portion in plan view.
3. The printed wiring board of claim 2, wherein the base film further comprises a third portion; the first portion is sandwiched between the second portion and the third portion in the first direction; the boundary between the first portion and the third portion, i.e., the second boundary, is along the second direction in plan view; the first wiring comprises: a fifth coil portion located in the first portion and wound in a spiral shape in plan view; and a sixth coil portion located in the third portion and wound in a spiral shape in plan view; the second wiring comprises: a seventh coil portion located in the first portion and wound in a spiral shape in plan view; and an eighth coil portion located in the third portion and wound in a spiral shape in plan view; The aforementioned 7th coil portion and the aforementioned 8th coil portion overlap the aforementioned 5th coil portion and the aforementioned 6th coil portion respectively when viewed from above; and when the aforementioned base film is bent along the aforementioned 1st boundary in a manner where the aforementioned 1st coil portion overlaps the aforementioned 2nd coil portion when viewed from above, and when the aforementioned base film is bent along the aforementioned 2nd boundary in a manner where the aforementioned 5th coil portion overlaps the aforementioned 6th coil portion when viewed from above, the aforementioned 2nd portion is arranged separately from the aforementioned 3rd portion.
4. A coil device comprising: a base film having a first main surface and a second main surface; a first wiring disposed on the first main surface; and a second wiring disposed on the second main surface; wherein the base film has a first portion and a second portion; the first portion and the second portion are arranged along the length direction of the base film in a plan view, i.e., a first direction, in a state before the base film is bent; the boundary between the first portion and the second portion, i.e., a first boundary, is along a second direction orthogonal to the first direction in a plan view; the first wiring comprises: a first coil portion located in the first portion and wound into a spiral shape in a plan view; and a second coil portion located in the second portion and wound into a spiral shape in a plan view; the width of the first portion in the first direction is greater than the width of the second portion in the first direction. The aforementioned base film, viewed from above, is bent along the aforementioned first boundary in such a way that the aforementioned first coil portion overlaps the aforementioned second coil portion; and the aforementioned first portion, in the state after the aforementioned base film is bent, partially overlaps the aforementioned second portion in a top view.
5. The coil device of claim 4, wherein the second wiring comprises: a third coil portion located in the first portion and wound in a spiral shape in plan view; and a fourth coil portion located in the second portion and wound in a spiral shape in plan view; and the third coil portion and the fourth coil portion are respectively superimposed on the first coil portion and the second coil portion in plan view.
6. The coil device of claim 5, wherein the first main surface located in the first part is partially facing the first main surface located in the second part in the state after the bottom film is bent; the first wiring further includes a first connecting portion connecting the first coil portion and the second coil portion; and the first connecting portion extends in a manner that crosses the first boundary.
7. The coil device of claim 4, wherein the second main surface of the first part is partially facing the second main surface of the second part in the bent state of the base film; the second part is separated from the first part in the bent state of the base film; and further includes: an electronic component disposed between the first part and the second part in the bent state of the base film, and connected to the second wiring.
8. The coil device of claim 5, wherein the base film further comprises a third portion; the first portion is sandwiched between the second and third portions in the first direction in the state before the base film is bent; the boundary between the first and third portions is the second boundary, along the second direction; the first wiring comprises: a fifth coil portion located in the first portion and wound in a spiral shape in plan view; and a sixth coil portion located in the third portion and wound in a spiral shape in plan view; the second wiring comprises: a seventh coil portion located in the first portion and wound in a spiral shape in plan view; and an eighth coil portion located in the third portion and wound in a spiral shape in plan view; The aforementioned 7th coil portion and the aforementioned 8th coil portion overlap the aforementioned 5th coil portion and the aforementioned 6th coil portion respectively when viewed from above; and the aforementioned base film is bent along the aforementioned 1st boundary in a manner where the aforementioned 1st coil portion overlaps the aforementioned 2nd coil portion when viewed from above, and is bent along the aforementioned 2nd boundary in a manner where the aforementioned 5th coil portion overlaps the aforementioned 6th coil portion when viewed from above; the aforementioned 2nd portion is separated from the aforementioned 3rd portion in the bent state of the aforementioned base film.
9. The coil device of claim 8, wherein the first main surface located in the first part is partially facing the first main surface located in the third part in the state after the bottom film is bent; the first wiring further includes a second connecting portion connecting the fifth coil portion and the sixth coil portion; and the second connecting portion extends in a manner that crosses the second boundary.
10. The coil device of claim 8 further includes: an electronic component disposed between the second part and the third part in the bent state of the base film.