Substrate unit and solder connection structure

Abstract

To provide a substrate unit and a solder connection structure that makes it easy to check the state in which a substrate and a flat wiring material are soldered.SOLUTION: A substrate unit 1 to which a solder connection structure 40 is applied includes a substrate 10 on which electronic components 20 are mounted and which includes a board-side conductive surface 12 formed on a surface 11, and a flat wiring material 30 which is made of a flexible transparent material and which includes a wiring material-side conductive surface 32 formed on a surface 31, and the board-side conductive surface 12 is formed larger than the wiring material-side conductive surface 32 and is connected to the wiring material-side conductive surface 32 via solder S.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a board unit and a solder connection structure. [Background technology]

[0002] For example, Patent Document 1 discloses a cable connection structure in which a board and an FPC cable are directly connected by soldering. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-200779 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the cable connection structure described in Patent Document 1 mentioned above, the connection portion of the board and the connection portion of the FPC cable overlap, which may make it difficult to check the state in which the board and the FPC cable are soldered, and in this regard, there is room for further improvement.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a board unit and a solder connection structure that make it easy to check the state in which the board and flat wiring material are soldered. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the board unit of the present invention comprises a board on which electronic components are mounted and which includes a board-side conductive surface formed on its surface, and a flat wiring material which is made of a flexible transparent material and which includes a wiring material-side conductive surface formed on its surface, and which is characterized in that the board-side conductive surface is formed larger than the wiring material-side conductive surface and is connected to the wiring material-side conductive surface via solder.

[0007] In order to achieve the above-mentioned object, the solder connection structure of the present invention comprises a board-side conductive surface formed on the surface of a board on which an electronic component is mounted, a wiring material-side conductive surface formed on the surface of a flat wiring material made of a flexible transparent material, and solder electrically connecting the board-side conductive surface and the wiring material-side conductive surface, wherein the board-side conductive surface is formed larger than the wiring material-side conductive surface, and the solder protrudes into at least the area between the outer edge of the wiring material-side conductive surface and the outer edge of the board-side conductive surface. Effect of the Invention

[0008] The board unit and solder connection structure according to the present invention have the advantage that it is possible to easily check the state in which the board and the flat wiring material are soldered. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a board unit to which a solder connection structure according to this embodiment is applied. [Diagram 2] FIG. 2 is a top view showing a schematic configuration of a substrate-side conductive surface applied to the substrate according to this embodiment. [Diagram 3] FIG. 3 is a top view showing a schematic configuration of a wiring material-side conductive surface applied to the flat wiring material according to this embodiment. [Figure 4] FIG. 4 is a top view showing a schematic configuration of a board unit to which the solder connection structure according to the present embodiment is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that are replaceable and easy for a person skilled in the art, or those that are substantially the same.

[0011] [Embodiment] The board unit 1 shown in Fig. 1 is typically applied to an electronic control unit (ECU) mounted on a vehicle and electronically controlling the operation of various devices, and a solder connection structure 40 is applied between a board 10 and a flat wiring material 30 connected to the board 10, and a board-side conductive surface 12 provided on the board 10 is formed larger than a wiring material-side conductive surface 32 provided on the flat wiring material 30, thereby realizing a configuration that makes it easy to check the state in which the board 10 and the flat wiring material 30 are soldered. Hereinafter, the configurations of the board unit 1 and the solder connection structure 40 will be described in detail with reference to Figs. 1 to 4.

[0012] In the following description, of the first, second, and third directions that intersect with one another, the first direction is referred to as the "first width direction X," the second direction is referred to as the "second width direction Y," and the third direction is referred to as the "thickness direction Z." Here, the first width direction X, the second width direction Y, and the thickness direction Z are perpendicular to one another. Unless otherwise specified, the directions used in the following description are described as directions in a state in which the various parts of the board unit 1 are assembled.

[0013] [Board unit] As shown in FIG. 1, the board unit 1 includes a board 10, an electronic component 20, a flat wiring material 30, and a solder connection structure 40.

[0014] The substrate 10 is a plate-like member on which various electronic components 20 are mounted and which constitutes an electronic circuit that electrically connects the electronic components 20 to each other, and is a printed circuit board (PCB) in which the electronic components 20 are soldered to a rigid substrate. The substrate 10 is formed in a substantially rectangular shape that extends along a first width direction X and a second width direction Y and whose thickness direction Z is the plate thickness direction. The substrate 10 is formed by printing a wiring pattern (printed pattern) using a conductive material such as copper on an insulating layer such as epoxy resin, glass epoxy resin, paper epoxy resin, or ceramic, and the circuit body is formed by the wiring pattern.

[0015] The electronic components 20 are elements that are mounted on the substrate 10 and electrically connected to perform various functions, and are, for example, capacitors, relays, resistors, transistors, electronic control units including microcomputers, and the like.

[0016] The flat wiring material 30 is made of a plate-like member having flexibility, and is connected to the surface 11 of the substrate 10 on which the electronic component 20 is mounted. The flat wiring material 30 of this embodiment is a flexible printed circuit (FPC: Flexible Printed Circuits). The flexible printed circuit is formed by bonding a coverlay film to a transparent base film (also called a substrate) made of polyimide or the like via an adhesive layer. In addition, the flexible printed circuit has a wiring pattern formed by a conductor foil bonded to at least one surface of the base film, and the wiring pattern constitutes a circuit body. Therefore, the flat wiring material 30 is mounted on the substrate 10 as a member constituting a part of an electronic circuit that electrically connects the electronic component 20 mounted on the substrate 10 to electronic components mounted on members other than the substrate 10 and external devices.

[0017] The base film constituting the flat wiring material 30 is not particularly limited in its transparency as long as it is transparent enough to visually view the other side from one side formed in a plate shape, and may be made of a translucent material. The flat wiring material 30 of this embodiment is formed to be transparent as a whole by being composed of a transparent base film, but the range (area) surrounding at least the wiring material side conductive surface 32 is transparent, and as long as the range (area) is transparent enough to visually view the wiring material side conductive surface 32 from one side of the base film, the range of the transparent portion is not particularly limited.

[0018] In addition, the flat wiring material 30 is described here as a flexible printed circuit board, but may be a flexible flat cable (FFC). A flexible flat cable is a multi-core electric wire in which plate-shaped conductors are arranged in parallel, and is formed by sandwiching both sides of the conductor with an insulator (a transparent film such as a plastic film tape) and joining each member by heat welding or thermal fusion. A flexible flat cable is a circuit body that can electrically connect electronic components 20 to each other by passing electricity through the conductor. Therefore, like a flexible printed circuit board, a flexible flat cable is mounted on the substrate 10 as a member that constitutes a part of an electronic circuit that electrically connects the electronic components 20 mounted on the substrate 10 to electronic components mounted on members other than the substrate 10 and external devices.

[0019] [Solder connection structure] The solder connection structure 40 includes a board-side conductive surface 12, a wiring material-side conductive surface 32, and solder S, as shown in FIGS.

[0020] The board-side conductive surface 12 is an electrode provided on the board 10, and is a conductor foil portion formed on the surface 11 (mounting surface) on which the electronic component 20 is mounted. The board-side conductive surface 12 in this embodiment is a pad formed for soldering a surface-mounted component.

[0021] 2, the board-side conductive surface 12 is formed in a substantially rectangular shape, with the long sides extending in the first width direction X and the short sides extending in the second width direction Y. Three board-side conductive surfaces 12 are provided, and the board-side conductive surfaces 12 are arranged at intervals along the second width direction Y.

[0022] 3, the wiring material side conductive surface 32 is an electrode provided on the end portion 30a of the flat wiring material 30, and is a conductor foil portion formed on the surface 31 arranged opposite the board side conductive surface 12 when the flat wiring material 30 is connected to the board 10 via the solder S (see FIG. 1). The wiring material side conductive surface 32 in this embodiment is a pad, similar to the board side conductive surface 12.

[0023] 3, the wiring material side conductive surface 32 is formed in a substantially rectangular shape, with the long side being in the first width direction X and the short side being in the second width direction Y. Three wiring material side conductive surfaces 32 are provided, and each wiring material side conductive surface 32 is arranged at intervals along the second width direction Y. Each wiring material side conductive surface 32 is formed at a position overlapping with the board side conductive surface 12 when the flat wiring material 30 is connected to the board 10 via the solder S, as shown in FIG.

[0024] 4, in this embodiment, the board-side conductive surface 12 is formed larger than the wiring material-side conductive surface 32, and the outer edge 32a of the wiring material-side conductive surface 32 is located inside the outer edge 12a of the board-side conductive surface 12 while overlapping with the board-side conductive surface 12. Therefore, between the wiring material-side conductive surface 32 and the board-side conductive surface 12, there are formed an area E1 where the wiring material-side conductive surface 32 overlaps with the board-side conductive surface 12, and an area E2 as a surplus part where the wiring material-side conductive surface 32 does not overlap with the board-side conductive surface 12. Note that the area E1 here is an area formed inside the outer edge 32a of the wiring material-side conductive surface 32, and the area E2 is an area formed between the outer edge 32a of the wiring material-side conductive surface 32 and the outer edge 12a of the board-side conductive surface 12.

[0025] The solder S is an alloy mainly composed of lead and tin used for soldering, and electrically connects the board-side conductive surface 12 and the wiring material-side conductive surface 32. The solder S of this embodiment is mixed with a thermosetting adhesive and applied to the board-side conductive surface 12. When heat is applied to the thermosetting adhesive sandwiched between the board-side conductive surface 12 and the wiring material-side conductive surface 32, the particles of the solder S melt, electrically connecting the board-side conductive surface 12 and the wiring material-side conductive surface 32. The thermosetting adhesive hardens, physically connecting the board-side conductive surface 12 and the wiring material-side conductive surface 32.

[0026] The solder S also protrudes outward from the region E1 where the board-side conductive surface 12 and the wiring material-side conductive surface 32 overlap. Therefore, as shown in Fig. 4, the solder S protrudes into the region E2 formed between the outer edge 32a of the wiring material-side conductive surface 32 and the outer edge 12a of the board-side conductive surface 12, and the solder S surrounding the outer edge 32a of the wiring material-side conductive surface 32 can be visually confirmed from the transparent base film constituting the flat wiring material 30.

[0027] In addition, as long as the solder S at least partially protrudes into the region E2 between the outer edge 32a of the wiring material side conductive surface 32 and the outer edge 12a of the board side conductive surface 12, the position of the portion protruding from the outer edge 32a of the wiring material side conductive surface 32 and the amount of the portion protruding from the outer edge 32a are not particularly limited.

[0028] The board unit 1 described above includes a board 10 on which electronic components 20 are mounted and which includes a board-side conductive surface 12 formed on a surface 11, and a flat wiring material 30 which is made of a flexible transparent material and which includes a wiring material-side conductive surface 32 formed on a surface 31. The board-side conductive surface 12 is formed larger than the wiring material-side conductive surface 32, and is connected to the wiring material-side conductive surface 32 via solder S.

[0029] According to this configuration, the board unit 1 has the board-side conductive surface 12 and the wiring material-side conductive surface 32 overlapping each other, and the area E1 connected via the solder S is visible from the flat wiring material 30 side, making it easy to check the state in which the board-side conductive surface 12 and the wiring material-side conductive surface 32 are soldered. Therefore, the board unit 1 can visually check whether the wiring material-side conductive surface 32 is properly soldered to the board-side conductive surface 12 without using a dedicated device such as an X-ray inspection device, thereby reducing the cost of inspection. In addition, the board unit 1 can connect the flat wiring material 30 to the board 10 without using a connecting part such as a connector, so that the part cost and the man-hours on the manufacturing line required for connector connection can be reduced.

[0030] Furthermore, in the board unit 1 described above, the board-side conductive surface 12 and the wiring material-side conductive surface 32 are formed in a rectangular shape, and the outer edge 32a of the wiring material-side conductive surface 32 is located inside the outer edge 12a of the board-side conductive surface 12 while overlapping with the board-side conductive surface 12. In addition, the solder S located between the board-side conductive surface 12 and the wiring material-side conductive surface 32 protrudes into at least the region E2 between the outer edge 32a of the wiring material-side conductive surface 32 and the outer edge 12a of the board-side conductive surface 12. According to this configuration, the board unit 1 makes it easy to check the state in which the board-side conductive surface 12 and the wiring material-side conductive surface 32 are soldered, since the solder S protruding from the wiring material-side conductive surface 32 is visible from the flat wiring material 30 side. Therefore, it is possible to efficiently visually check whether the wiring material side conductive surface 32 of the board unit 1 is entirely soldered to the board side conductive surface 12 or not.

[0031] Furthermore, the solder connection structure 40 described above includes the board-side conductive surface 12, the wiring material-side conductive surface 32, and the solder S that electrically connects the board-side conductive surface 12 and the wiring material-side conductive surface 32, and the board-side conductive surface 12 is formed larger than the wiring material-side conductive surface 32, and the solder S at least protrudes into the region E2 between the outer edge 32a of the wiring material-side conductive surface 32 and the outer edge 12a of the board-side conductive surface 12. According to this configuration, the board unit 1 to which the solder connection structure 40 is applied can easily check the state in which the board-side conductive surface 12 and the wiring material-side conductive surface 32 are soldered, as described above, because the solder S protruding from the wiring material-side conductive surface 32 is visible from the flat wiring material 30 side. Therefore, the board unit 1 can efficiently check visually whether the wiring material-side conductive surface 32 is entirely soldered to the board-side conductive surface 12.

[0032] The substrate unit 1 and the solder connection structure 40 according to the above-described embodiment of the present invention are not limited to the above-described embodiment, and various modifications are possible within the scope of the claims.

[0033] For example, the shapes of the board-side conductive surface 12 and the wiring material-side conductive surface 32 are not limited to rectangular shapes.

[0034] In addition, the number of the board-side conductive surface 12 and the wiring material-side conductive surface 32 is not particularly limited. In addition, the position of the board-side conductive surface 12 with respect to the board 10 and the position of the wiring material-side conductive surface 32 with respect to the flat wiring material 30 are not particularly limited to the form shown in FIG.

[0035] Further, although the board-side conductive surface 12 and the wiring material-side conductive surface 32 have been described as pads, there are no particular limitations on the form thereof as long as they are conductive surfaces. [Explanation of symbols]

[0036] 1 Board unit 10 Substrate 11 Surface of the board 12 Conductive surface on the board side 12a Outer edge of the conductive surface on the board side 20 Electronic Components 30 Flat wiring material 31 Surface of flat cable conductor 32 Routing material side conduction surface 32a Outer edge of the conductive surface of the wiring material 40 Solder joint structure E2 The area between the outer edge of the conductive surface on the wiring material side and the outer edge of the conductive surface on the board side S solder X 1st width direction Y Second width direction Z thickness direction

Claims

1. A substrate on which electronic components are mounted and which includes a substrate-side conductive surface formed on a surface thereof; A flat wiring material made of a flexible transparent material and including a wiring material side conductive surface formed on a surface thereof, The board-side conductive surface is formed larger than the wiring material-side conductive surface, and is connected to the wiring material-side conductive surface via solder. Board unit.

2. The board-side conductive surface and the wiring material-side conductive surface are formed in a rectangular shape, The outer edge of the wiring material side conductive surface is located inside the outer edge of the board side conductive surface while overlapping with the board side conductive surface, The solder located between the board-side conductive surface and the wiring material-side conductive surface protrudes into at least a region between the outer edge of the wiring material-side conductive surface and the outer edge of the board-side conductive surface. The substrate unit according to claim 1 .

3. a board-side conductive surface formed on a surface of a board on which electronic components are mounted; A wiring material side conductive surface formed on a surface of a flat wiring material made of a flexible transparent material; and a solder that electrically connects the board-side conductive surface and the wiring material-side conductive surface, The substrate-side conductive surface is formed larger than the wiring material-side conductive surface, The solder protrudes into at least an area between an outer edge of the wiring material side conductive surface and an outer edge of the board side conductive surface. Solder connection structure.

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