ELECTRONIC CIRCUIT

Abstract

Electronic circuit (80), comprising: - a first printed circuit board (9); - a second circuit board (10, 30, 50, 210, 310, 420) mounted on the first circuit board (9) such that an edge (10A, 30A, 50A, 210A, 310A, 420A) of the second circuit board (10, 30, 50, 210, 310, 420) borders a part mounting surface (9A) of the first circuit board (9) on which a part (3, 5, 7) is mounted; - a third circuit board (20, 40, 60, 220, 320, 410) mounted on the first circuit board (9) such that an edge (20A, 40A, 60A, 220A, 410A) of the third circuit board (20, 40, 60, 220, 320, 410) borders on the partial mounting surface (9A), wherein - the second circuit board (10, 30, 50, 210, 310, 420) and the third circuit board (20, 40, 60, 220, 320, 410) are connected to each other in a state in which a board thickness direction of the second circuit board (10, 30, 50, 210, 310, 420) and a board thickness direction of the third circuit board (20, 40, 60, 220, 320, 410) are aligned in different directions from each other about a normal to the partial mounting surface (9A), and - at least one of the second circuit board (10, 30, 50, 210, 310, 420) and the third circuit board (20, 40, 60, 220, 320, 410) is provided with an antenna pattern (15, 35, 53, 54, 214), - a position regulating section (91, 92, 93, 94) provided in the first circuit board (9) for regulating a mounting position of the second circuit board (10) with respect to the first circuit board (9), - a projection (21) provided on one edge (20A) of the third circuit board (20), and - a hole (95) or a recess provided in the first circuit board (9), the hole (95) or the recess receiving the projection (21) when the second circuit board (10) and the third circuit board (20) are connected to each other and the second circuit board (10) is arranged at the mounting position regulated by the position regulating section (91, 92, 93, 94), wherein - the hole (95) or the recess has an inner diameter which is designed to increase depending on the distance from a connecting portion between the second circuit board (10) and the third circuit board (20).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electronic circuit having an antenna pattern. STATE OF THE ART

[0002] A conventional electronic device such as a wireless telematics device (hereinafter referred to as a TCU) may internally include an electronic circuit having an antenna. As structures for such an antenna, various structures have been proposed besides the structure in which an antenna pattern is formed on a main board of an electronic circuit (e.g., a printed circuit board on which an IC chip or the like is mounted). Specifically, a structure in which an antenna pattern is formed on a rigid board, an antenna formed by machining a sheet, a flexible printed circuit (hereinafter referred to as a FPC), or an antenna formed by laser direct structuring (hereinafter referred to as a LDS) have been proposed.However, in various antennas different from the structure in which the antenna pattern is formed on the main board, the antenna is usually mounted on the main board in a step other than the soldering step for surface mounting or the like, thereby inhibiting an increase in productivity of the electronic circuit.

[0003] In contrast, WO 2015 / 158 500 A1 proposes to attach a printed circuit board (hereinafter antenna board) formed with an antenna pattern to a main board by reflow soldering, orthogonally to the main board, by surface mounting.

[0004] However, after careful investigation by the inventors, it was discovered that there is a possibility of an antenna board falling over during reflow soldering. Therefore, it is conceivable that an actual implementation of the technology according to WO 2015 / 158500 A1 might require a step for attaching a special structural part to the antenna board or the main board. In such a case, the production cost of the electronic circuit will increase and the size of the electronic circuit will increase.

[0005] From US 2015 / 0 085 903 A1, a wireless connector is further known, comprising: a first communication device configured to wirelessly transmit a modulated signal containing a carrier signal modulated with a digital signal by radiation coupling, and a second communication device configured to receive the modulated signal, wherein the first and second communication devices are coupled via at least one wired connection that transmits a signal used to demodulate the modulated signal.

[0006] DE 32 09 914 A1 relates to a hearing aid with an amplifier circuit, and JP H02-132 970 U describes a possibility for attaching or connecting multiple circuit boards. Furthermore, DE 10 54 515 A discloses a printed wiring or printed circuit with line crossings, and DE 20 2015 008 007 U1 discloses a printed circuit board arrangement with at least two printed circuit boards. JP 2017-17 089 A relates to a further printed circuit board arrangement, and WO 2007 / 036 181 A1 teaches a connection between two printed circuit boards or printed circuit boards by means of mechanical locking. SUMMARY OF THE INVENTION

[0007] It is an object of the present disclosure to provide an electronic circuit in which surface mounting of an antenna pattern on a predetermined circuit board in a standing position with respect to the predetermined circuit board can be improved.

[0008] The problem is solved by the subject matter of the main claim. Advantageous further developments are specified in the subclaims.

[0009] According to the present invention, the first to third circuit boards are connected so that no two circuit boards are parallel to each other. Therefore, the antenna pattern formed on the second or third circuit board can be maintained in a standing position with respect to the first circuit board. That is, the antenna pattern can be mounted on the first circuit board in the standing position with respect to the first circuit board, thereby eliminating the use of a dedicated structural member other than the circuit boards. Further, an antenna board is arranged to rise from the first circuit board by connecting the three circuit boards. Therefore, it is possible to stably maintain the standing position. Therefore, a dedicated structural member for supporting or holding the antenna board can be omitted. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a perspective view of an antenna unit according to a first embodiment. Fig. Figure 2 shows a perspective view of an electronic circuit incorporated in the antenna unit. Fig. 3 shows a perspective view of a pair of boards, including an antenna board, in the electronic circuit. Fig. 4 shows a perspective view of a connection structure of printed circuit boards as the pair of boards. Fig. 5 shows a perspective view of another pair of boards in the electronic circuit. Fig. 6 shows a perspective view of yet another pair of circuit boards in the electronic circuit. Fig. 7 shows a flowchart illustrating part of a manufacturing process of the electronic circuit. Fig. 8 is a plan view illustrating an arrangement and size of through holes in the electronic circuit. Fig. 9 shows a perspective view of a pair of circuit boards according to a second embodiment. Fig. 10 is a schematic view illustrating a connection mechanism of a pair of circuit boards according to a third embodiment. Fig. 11 is a schematic view illustrating an effect achieved by the linkage mechanism. Fig. 12 is a perspective view showing a connecting mechanism of printed circuit boards according to a fourth embodiment. DESCRIPTION OF EMBODIMENTS

[0010] Embodiments of the present disclosure will be described below with reference to the drawings. [1. First embodiment][1- 1. Overall structure]

[0011] As in Fig. As shown in Figure 1, the antenna unit 1 of the first embodiment is an in-vehicle antenna unit. The antenna unit 1 includes a housing 2 having a substantially rectangular parallelepiped shape and two connectors 3 and 5 exposed from a side surface of the housing 2. As shown in Fig. 2, these two connectors 3 and 5, together with an IC chip 7, are surface-mounted (hereinafter simply referred to as "mounted") on a main circuit board 9 by reflow soldering and housed in the case 2. In addition, six printed circuit boards 10, 20, 30, 40, 50, and 60, which are smaller than a printed circuit board constituting the main circuit board 9, are mounted on the main circuit board 9 by reflow soldering.

[0012] The main board 9 and the two connectors 3 and 5, the IC chip 7, and the six circuit boards 10 to 60 mounted on the main board 9 constitute an electronic circuit 80 of the first embodiment. Hereinafter, the positional relationships of the respective parts will be described using a right-handed coordinate system in which a direction in which the two connectors 3 and 5 are exposed from the case 2 is defined as the X direction (i.e., +X direction), and a direction in which a partial mounting surface 9A of the main board 9, on which parts such as the IC chip 7 and the like are mounted, faces is defined as the Z direction (i.e., +Z direction). However, such a coordinate system is defined merely for the convenience of explaining the positional relationships of the respective parts and is irrelevant to positions and positional relationships in actual use.The antenna unit 1 can be used in any position, for example, such as a position in which the +Z direction corresponds to an upward direction or a position in which the +X direction corresponds to the upward direction.

[0013] As in Fig. 1, the housing 2 has an outer shape that is substantially a rectangular parallelepiped, in which the dimension in the ± Z direction is shorter than the dimension in the ± X direction and the dimension in the ± Y direction, and the dimension in the ± X direction and the dimension in the ± Y direction are substantially equal. As shown in Fig. 2, each of the six printed circuit boards 10 to 60 is a rigid board having a rectangular plate shape and mounted on the partial mounting surface 9A such that the short sides of the rectangular shape are parallel to a normal perpendicular to the partial mounting surface 9A. Structures of each of the six printed circuit boards 10 to 60 are described in detail below. [1- 2. Structure of pairs of boards with antenna boards]

[0014] As in Fig. 3, the circuit board 10, which has the shape of a rectangular plate, is mounted such that an edge 10A corresponding to a long side of the rectangular shape borders the partial mounting surface 9A. During assembly, the circuit board 10 is arranged such that the edge 10A extends in the ± X direction.

[0015] The printed circuit board 10 has four protrusions 11, 12, 13, and 14 projecting from the edge 10A in the -Z direction. The four protrusions 11, 12, 13, and 14 are arranged in the specified order from the end located on the -X side when the printed circuit board 10 is assembled. The protrusion 11 is provided at a position offset from the -X side on the edge 10A. In contrast, the three protrusions 12, 13, and 14 are arranged in an area offset from the center of the edge 10A in the +X direction. The protrusion 13 is provided to serve as an electrode for supplying electrical power to an antenna pattern 15 formed on the printed circuit board 10. That is, the circuit board 10 serves as an antenna board and forms a board pair (ie, a pair of circuit boards) with a circuit board 20, as described below.

[0016] The printed circuit board 20, which has the shape of a rectangular plate, is mounted so that an edge 20A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. During assembly, the printed circuit board 20 is arranged so that the edge 20A extends in the ±Y direction. The printed circuit board 20 has a projection 21 on the edge 20A at a position near the center of the edge 20A, with the projection 21 projecting in the ±Z direction. A short side of the printed circuit board 20 on the ±Y side is connected to a short side of the printed circuit board 10 on the ±X side via solder H as follows.

[0017] As in Fig. 4, the circuit board 10 has two through holes 18 and 19 in an area adjacent to the short side on the -X side. The two through holes 18 and 19 are aligned in the ±Z direction, and each of the two through holes 18 and 19 has a rectangular shape with the long side extending in the ±Z direction. The circuit board 20 has, at the edge on the -Y side, an engaging portion 22 projecting in the -Y direction to be engaged with the through hole 18 while being passed through the through hole 18, and an engaging portion 23 projecting in the -Y direction to be engaged with the through hole 19 while being passed through the through hole 19. At a tip end of the engaging portion 22, an extending portion 22A extending in the -Z direction is formed.Similarly, at a tip end of the engaging portion 23, an extending portion 23A extending in the -Z direction is formed.

[0018] The dimension of the through-hole 18 in the ±Z direction is slightly larger than the dimension of the end of the engaging portion 22, including the extending portion 22A, in the ±Z direction. Likewise, the dimension of the through-hole 18 in the ±X direction is slightly larger than the dimension of the end of the engaging portion 22, including the extending portion 22A, in the ±X direction. Likewise, the dimension in the ±Z direction and the dimension in the ±X direction of the through-hole 19 are slightly larger than the dimension in the ±Z direction and the dimension in the ±X direction of the end of the engaging portion 23, including the extending portion 23A. Therefore, the two engagement portions 22 and 23 together with the respective extension portions 22A and 23A can pass through the two through holes 18 and 19 in the Y direction.The positions of the two through holes 18 and 19 are set so that the extending portion 22A engages with a peripheral edge of the through hole 18 on the -Z side, and the extending portion 23A engages with a peripheral edge of the through hole 19 on the -Z side, in a state where the edge 10A and the edge 20A are on the same plate after the engaging portions 22 and 23 are passed through the through holes 18 and 19. That is, the two engaging portions 22 and 23, including the respective extending portions 22A and 23A, are provided as key shapes that engage the two through holes 18 and 19 from the +Z side.

[0019] The two circuit boards 10 and 20 are soldered together via solder H in the state where the two extension portions 22A and 23A are engaged with the peripheral edges of the through holes 18 and 19 on the -Z side as described above. This firmly connects the two circuit boards 10 and 20. Furthermore, the engagement directions of the two extension portions 22A and 23A with respect to the respective through holes 18 and 19 correspond to the pressing direction (-Z direction) in which the edge 10A of the circuit board 10 is pressed against the main board 9 when the two circuit boards 10 and 20 are fixed to the main board 9 by reflow soldering. Thereby, a lifting of the circuit board 10 as the antenna board from the main board 9 is advantageously limited, so that the conduction between the antenna pattern 15 and a pattern (not shown) on the main board 9 can be advantageously ensured.

[0020] Then, as in Fig. 5, the circuit board 30, which has the shape of a rectangular plate, is mounted so that an edge 30A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. During assembly, the circuit board 30 is arranged so that the edge 30A extends in the ±Y direction. The circuit board 30 has four projections 31, 32, 33, and 34 on the edge 30A at similar pitches to the four projections 11, 12, 13, and 14 of the circuit board 10. Of the four projections 31, 32, 33, and 34, the projection 33 is provided to serve as an electrode for supplying electrical power to an antenna pattern 35 formed on the circuit board 30. That is, the circuit board 30 serves as an antenna board and forms the board pair with the following circuit board 40.

[0021] The printed circuit board 40, which has the shape of a rectangular plate, is mounted so that an edge 40A corresponding to a long side of the rectangular shape abuts the partial mounting surface 9A. During assembly, the printed circuit board 40 is arranged so that the edge 40A extends in the ±X direction. The printed circuit board 40 has a projection 41 on the edge 40A at a position near the center of the edge 40A, which projects in the −Z direction. Similar to the printed circuit board 20, the printed circuit board 40 also has two engaging portions 42 and 43 on the short side on the −X side. The two engaging portions 42 and 43 are also connected by solder H in a state where they are passed through two through holes (not shown) formed in the printed circuit board 30 near the short side on the +Y side.It should be noted that the engagement states between the two through holes of the circuit board 30 and the two engagement portions 42 and 43 may be similar to or different from the engagement states between the two through holes 18 and 19 and the two engagement portions 22 and 23.

[0022] As in Fig. 6, the circuit board 50, which has the shape of a rectangular plate, is mounted so that an edge 50A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. During assembly, the circuit board 50 is arranged so that the edge 50A extends in the ±Y direction. The circuit board 50 has two projections 51 and 52 on the edge 50A at opposite ends in the ±Y direction, with the two projections 51 and 52 projecting in the −Z direction. The projection 51 is provided to serve as an electrode for supplying electrical power to an antenna pattern 53 formed on the circuit board 50. Further, the projection 52 is provided to serve as an electrode for supplying electrical power to an antenna pattern 54 formed on the circuit board 50. That is, the circuit board 50 serves as an antenna board and forms the board pair with the following circuit board 60.

[0023] The circuit board 60, which has the shape of a rectangular plate, is mounted so that an edge 60A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. During mounting, the circuit board 60 is arranged so that the edge 60A extends in the ±X direction. The circuit board 60 has a projection 61 on the edge 60A at a position near the end on the −X side, the projection 61 projecting in the −Z direction. The circuit board 60 has an engaging portion 62 at an edge on the +X side for engaging with a through hole (not shown) formed in the circuit board 50. This engaging portion is connected to the circuit board 50 via a solder H in a state where it is passed through the through hole.It should be noted that the engagement states between the through hole of the circuit board 50 and the engagement portion 62 may be similar to or different from the engagement state between the through hole 18 or 19 and the engagement portion 22 or 23. [1 - 3. Main board structure and antenna unit manufacturing process]

[0024] The pairs of circuit boards, including the antenna boards, with the structures described above are mounted on the main board 9 by a through-hole reflow technique (hereinafter THR for Through Hole Reflowing). In a manufacturing process for manufacturing an antenna unit 1, as shown in Fig. 7, in step S1, a worker first manufactures six printed circuit boards 10 to 60 as the basis of the circuit board pairs, including the antenna boards, as described above. Subsequently, in step S2, a worker assembles the six printed circuit boards 10 to 60 into the circuit board pairs by soldering.

[0025] Next, in step S3, a worker mounts the pairs of boards assembled in step S2 onto the main circuit board 9 (i.e., the TCU main board). Subsequently, in step S4, each pair of boards is soldered onto the main circuit board 9 by reflow soldering (i.e., reflow mounting). In step S5, an electronic circuit 80 is mounted on the housing 2. Thus, the fabrication of the antenna unit 1 is completed. Note that, in Fig. 7, the electronic circuit 80 is referred to as “ECU circuitry” and each of the pairs of circuit boards is referred to as “antenna subassembly (sub-assembly)”.

[0026] In the manufacturing process, in step S3, the projections 11, 12, 13, 14, 21, 31, 32, 33, 34, 41, 51, 52, and 61 of the respective circuit board pairs are received in the respective through holes 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, and 103 of the main board 9. It should be noted that the respective circuit board pairs have assembly errors. For example, as shown in Fig. 8, although an angle θ defined between the circuit board 10 and the circuit board 20 about the Z-axis is originally 90°, the probability that the angle θ is exactly 90° is not high.

[0027] Therefore, in the electronic circuit 80, an inner diameter of the through hole 95 is designed as follows. The mounting position of the printed circuit board 10 is regulated when the protrusions 11, 12, 13, and 14 are received in the corresponding through holes 91, 92, 93, and 94. Consequently, if the angle θ has an error, the position of the protrusion 21 of the printed circuit board 20 may have an error. For this reason, the inner diameter of the through hole 95 for receiving the protrusion 21 therein has a clearance with respect to an outer diameter of the protrusion 21. Also, the error in the position of the protrusion 21 increases depending on the distance of the protrusion 21 from a position (hereinafter, a connecting portion) where the printed circuit board 10 and the printed circuit board 20 are connected to each other.

[0028] Accordingly, in a case where the projection 21 is provided at a position farther from the connecting portion, preferably the inner diameter as shown in Fig. 8, is enlarged to equal to a through hole 95A. On the other hand, in a case where the projection 21 is provided at a position closer to the connecting portion, it is possible to increase the inner diameter as shown in Fig. 8, equal to a through hole 95B. In the present embodiment, the inner diameter of the through hole 95 is designed to increase depending on the distance from the connecting portion, as described above. [ 1 - 4. Effects]

[0029] In the first embodiment described above, the following effects are achieved.

[0030] (1A) In the first embodiment, since the circuit board 10, the circuit board 20, and the main board 9 are connected to each other such that no two circuit boards are parallel to each other, the antenna pattern formed in the circuit board 10 can be held in the standing position relative to the main board 9. That is, while prohibiting the use of a special structural member other than the circuit boards, the antenna pattern 15 can be surface-mounted on the main board 9 in a standing position relative to the main board 9. Further, the circuit board 10 as the antenna board is brought into the standing position relative to the main board 9 by connecting three circuit boards (that is, by connecting the main board 9 and the two circuit boards 10 and 20). Therefore, it is possible to maintain the standing position, and no special structural member for holding or supporting the antenna pattern 15 is required.Supports of the circuit board 10 as the antenna board are required (such as a structural part different from the circuit boards).

[0031] Similar effects are also achieved for the other pairs of boards as follows. The circuit board 30 as the antenna board is stably held in the standing position relative to the main board 9 by connecting three circuit boards (ie, by connecting the main board 9 and the two circuit boards 30 and 40), and the special structural part is not required. The circuit board 50 as the antenna board is stably held in the standing position relative to the main board 9 by connecting three circuit boards (ie, by connecting the main board 9 and the two circuit boards 50 and 60), and the special structural part is not required.

[0032] (1B) The six circuit boards 10 to 60 are mounted in the standing position relative to the main board 9, while the protrusions 11 to 61 are fitted into the through holes 91 to 103. Therefore, the three circuit boards 10, 30, and 50 as the antenna boards can be further stably held in the standing position. Moreover, each of the protrusions 11 to 52 is formed at a position different from ends of each edge 10A to 50A (such as different from a position where each of the protrusions 11 to 52 approaches the end point of each edge 10A to 50A). Therefore, even if the printed circuit boards constituting the pairs of boards have assembly errors as described above, the assembly errors are less likely to be reflected as position errors of the projections 11 to 52 compared with the case where the projections 11 to 52 are formed at the ends of the edges 10A to 50A.Thus, the occurrence of a situation in which the projections 11 to 52 cannot be received in the through holes 91 to 103 due to the defects is suppressed.

[0033] (1C) In the first embodiment, the design is such that the inner diameter of the through-hole 95 increases depending on the distance from the connecting portion between the two circuit boards 10 and 20. In this case, even if the two circuit boards 10 and 20 constituting the pair of boards have an assembly error as described above, the occurrence of the situation where the projection 21 cannot be received in the through-hole 95 due to the error is further advantageously suppressed.

[0034] (1D) The two engaging portions 22 and 23 of the printed circuit board 20 are respectively soldered to the two through-holes 18 and 19 formed in the printed circuit board 10 in the state where they are passed through the two through-holes 18 and 19. Therefore, the connection state of the two printed circuit boards 10 and 20 can be further strengthened. For example, even if the solder H is melted in the reflow soldering step in step S4, separation of the two printed circuit boards 10 and 20 can be restricted.

[0035] (1E) Moreover, the two engaging portions 22 and 23 have, at their tip ends, the extending portions 22A and 23A extending toward the edge 20A of the printed circuit board 20. The engaging portions 22 and 23 are soldered to the through-holes 18 and 19, respectively, in the states where the extending portions 22A and 23A are engaged with the peripheral edges on the -Z side of the two through-holes 18 and 19 (i.e., the peripheral edges of the through-holes 18 and 19 adjacent to the main board 9). Therefore, the lifting or lifting of the printed circuit board 10 in the direction away from the main board 9 (i.e., in the +Z direction) can be further advantageously suppressed. Accordingly, the conduction between the pattern (not shown) of the main board 9 and the antenna pattern 15 can be further advantageously ensured. [2. Second Embodiment][2- 1. Difference from the first embodiment]

[0036] The basic structure of the second embodiment is similar to the first embodiment, so the differences will be mainly described below, while the common structure will not be described repeatedly. An electronic circuit of the second embodiment differs from the first embodiment in that, as shown in the Fig. 9, a pair of boards with a circuit board 210 as an antenna board.

[0037] As in Fig. As shown in Figure 9, the circuit board 210, which has the shape of a rectangular plate, is mounted so that an edge 210A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. The circuit board 210 has three projections 211, 212, and 213 on the edge 210A, the three projections 211, 212, and 213 projecting in the Z direction. The projection 211 is provided to serve as an electrode for supplying electrical power to an antenna pattern 214 formed on the circuit board 210. The projections 212 and 213 are provided to serve as electrodes short-circuited across a pattern 215 formed on the circuit board 210.

[0038] A printed circuit board 220 constituting the pair of boards with the printed circuit board 210 has the shape of a rectangular plate and is mounted so that an edge 220A corresponding to a long side of the rectangular shape abuts the partial mounting surface 9A. The printed circuit board 220 has a projection 221 projecting in the Z direction on the edge 220A. The printed circuit board 220 has an engaging portion 222 on the edge on a side connected to the printed circuit board 210, the engaging portion 222 engaging a through hole (not shown) formed in the printed circuit board 210. The engaging portion 222 is soldered to the printed circuit board 210 via a solder H in a state where it is passed through the through hole.It should be noted that the engagement state of the engagement portion 222 and the through hole of the circuit board 210 may be similar to or different from the engagement state between the through hole 18 or 19 and the engagement portion 22 or 23. [2- 2. Effects]

[0039] In the second embodiment described above, in addition to the effects (1A) and (1D) of the first embodiment described above, the following effect is achieved.

[0040] (2A) In the second embodiment, the circuit board 210 as the antenna board has the two protrusions 212 and 213 serving as the electrodes short-circuited via the pattern 215 formed in the circuit board 210. In this case, since patterns for enabling electrical conduction between any two pins of the connector 3 or 5 and the two protrusions 212 and 213 are formed on the partial mounting surface 9A, it is possible to know whether or not the edge 210A is separated from the partial mounting surface 9A by checking the conduction state of the two pins.

[0041] As the second embodiment, in the case where the main board 9 on which the printed circuit board 210 is mounted as the antenna board is housed in the casing 2, it was not easy to know whether or not the printed circuit board 210 is separated from the partial mounting surface 9A after housing. Therefore, even in a situation where radio wave reception is poor, it was difficult to know whether the cause is due to the antenna pattern 214 or the like, or because the antenna pattern 214 is not in contact with the pattern formed on the partial mounting surface 9A. In the second embodiment, on the other hand, it is possible to know whether the edge 210A rises from the partial mounting surface 9A, that is, whether the antenna pattern 214 is in contact with the pattern formed on the partial mounting surface 9A, by checking the conduction state of the two pins (pins). [3. Third embodiment][3- 1. Difference from the first embodiment]

[0042] The basic structure of the third embodiment is similar to the first embodiment, so the differences will be mainly described below, while the common structure will not be described repeatedly. In the first embodiment, the circuit board 10 as the antenna board has the two rectangular through-holes 18 and 19 aligned in the ±Z direction. An electronic circuit of the third embodiment differs from the first embodiment in that, as shown in Fig. 10, has a circuit board 310 as an antenna board.

[0043] As in Fig. As shown in FIG. 10, the circuit board 310, which has the shape of a rectangular plate, is mounted so that an edge 310A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. The edge 310A can be arranged to extend in any direction on the partial mounting surface 9A. However, a case will be described below in which the circuit board 310 is arranged so that the edge 310A extends in the ±X direction, similar to the circuit board 10.

[0044] The circuit board 310 has three protrusions 312, 313, and 314 projecting in the Z direction on the edge 310A at similar positions to the three protrusions 12, 13, and 14 of the circuit board 10. At least one of the three protrusions 312 to 314 is provided to serve as an electrode for providing electrical energy to the antenna pattern (not shown) formed on the circuit board 310.

[0045] A printed circuit board 320 forms a pair of boards with the printed circuit board 310. The printed circuit board 320 has the shape of a rectangular plate and is mounted on the partial mounting surface 9A such that an edge 320A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. Furthermore, the printed circuit board 320 has two engaging portions 322 and 323 at the edge on a side to be connected to the printed circuit board 310. The two engaging portions 322 and 323 are arranged in the ±Z direction to engage two through holes 318 and 319 formed in the printed circuit board 310. The two engagement portions 322 and 323 have no extension portions, and each of the two engagement portions 322 and 323 has the shape of a mainly rectangular parallelepiped as a whole. The two through holes 318 and 319 each have an elliptical shape with a major axis in the ±Z direction.

[0046] The inner circumference of the through-hole 318 has a size that includes the outer circumference of the engaging portion 322 (ie, an outer circumference in a ZX cross section). Similarly, the inner circumference of the through-hole 319 has a size that includes the outer circumference of the engaging portion 323. For this reason, the two engaging portions 322 and 323, as shown in the Fig. 10 and Fig. 11, within the two through holes 318 and 319, respectively. The two through holes 318 and 319 are therefore arranged in this case such that the two engagement sections 322 and 323, as shown in Fig. 10, in a situation where the engaging portion 322 is in contact with an inner wall of the through-hole 318 on the -X side and the engaging portion 323 is in contact with an inner wall of the through-hole 319 on the +X side, are aligned in the ±Z direction. The two engaging portions 322 and 323 are soldered to the circuit board 310 in the state where the engaging portion 322 is in contact with the inner wall of the through-hole 318 on the -X side and the engaging portion 323 is in contact with the inner wall of the through-hole 319 on the +X side. [3- 2. Effects]

[0047] In the third embodiment described above, the following effects are achieved in addition to the effects (1A) and (1D) of the first embodiment described above.

[0048] (3A) In the third embodiment, the two engaging portions 322 and 323 are formed as shown in Fig. 10, soldered to the circuit board 310 in the state in which the engaging portion 322 is in contact with the inner wall of the through-hole 318 on the -X side and the engaging portion 323 is in contact with the inner wall of the through-hole 319 on the +X side. Consequently, if the solder used to solder the engaging portions 322 and 323 to the through-holes 318 and 319 is accidentally melted in the reflow soldering step, the edge of the circuit board 320 on the +Z side, as shown in Fig. 11, fall in the +X direction (i.e. away from the housing 2).

[0049] According to the third embodiment, in the case where the two through-holes 318 and 319 are designed to have the inner peripheries loosely surrounding the outer peripheries 322 and 323 of the two engaging portions 322 and 323 passed through the two through-holes 318 and 319, the two engaging portions 322 and 323 can be easily inserted into the two through-holes 318 and 319, respectively. However, when the parts such as the paired boards in which a plurality of circuit boards are soldered together are mounted on another circuit board and reflow soldering is performed, there is a possibility that the solder used for soldering the fabrications of the paired boards or the like is melted. In such a case, displacement of the circuit boards of the paired boards in undesirable directions is preferably suppressed.In the third embodiment, due to the structure described above, even if the solder connecting the two engaging portions 322 and 323 of the circuit board 320 to the circuit board 310 is melted, displacement of the circuit board 320 toward the housing 2 can be suppressed. [4. Fourth Embodiment][4- 1. Difference from the first embodiment]

[0050] The basic structure of the fourth embodiment is similar to the first embodiment, so the differences will be mainly described below, while the common structure will not be described repeatedly. In the first embodiment, the circuit board 10 as the antenna board has the two through holes 18 and 19, and the circuit board 20 has the two engaging portions 22 and 23. An electronic circuit of the fourth embodiment differs as shown in Fig. 12, from the first embodiment, a circuit board 410 as the antenna board has an engaging portion 413 and a circuit board 420 has a through hole 423.

[0051] As in Fig. As shown in FIG. 12, the printed circuit board 410, which has the shape of a rectangular plate, is mounted so that an edge 410A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. The edge 410A can be arranged to extend in any direction on the partial mounting surface 9A. However, a case will be described below in which the printed circuit board 410 is arranged so that the edge 410A extends in the ±X direction, similar to the printed circuit board 10.

[0052] The printed circuit board 410 has a surface-mount technology (SMT) terminal 411 at a central portion on the edge 410A. The terminal 411 has a planar shape with a length of one-half or more of the edge 410A and faces the partial mounting surface 9A. The printed circuit board 410 has a protrusion 412 at one end of the edge 410A on the +X side, with the protrusion 412 protruding in the -Z direction. At least one of the terminal 411 and the protrusion 412 is provided to serve as an electrode for supplying electric power to an antenna pattern (not shown) formed on the printed circuit board 410.

[0053] A printed circuit board 420 forms the circuit board pair with the printed circuit board 410. The printed circuit board 420 has the shape of a rectangular plate and is mounted on the partial mounting surface 9A such that an edge 420A corresponding to a long side of the rectangular shape is adjacent to the partial mounting surface 9A. Furthermore, the printed circuit board 420 has two projections 421 and 422 on the edge 420A. The printed circuit board 420 has a through hole 423 at one end on a side to be connected to the printed circuit board 410 (ie, on the -Y side). The through hole 423 has an elliptical shape with a major axis in the ±Z direction.

[0054] The circuit board 410 has an engaging portion 413 at an edge on the -X side, the engaging portion 413 protruding in the -X direction. The engaging portion 413 is provided to be passed through the through-hole 423 and engaged with the through-hole 423. Further, the engaging portion 413 has an extending portion 413A extending in the +Z direction at a tip end. The dimension of the through-hole 423 in the ±Z direction is slightly larger than the dimension of the engaging portion 413, including the extending portion 413A at the tip end, in the ±Z direction. Further, the dimension of the through hole 423 in the ±Y direction is slightly larger than the dimension of the engaging portion 413, including the tip end extending portion 413A, in the ±Y direction.

[0055] Therefore, the engaging portion 413, together with the extending portion 413A, can pass through the through-hole 423 in the -X direction. The position of the through-hole 423 is set so that the extending portion 413A engages with a peripheral edge of the through-hole 423 on the +Z side when the edge 410A and the edge 420A are on the same plane after the engaging portion 413 passes through the through-hole 423. That is, the engaging portion 413, including the extending portion 413A, has a key shape that engages with the through-hole 423 on the -Z side.

[0056] The two circuit boards 410 and 420 are soldered together in a state where the extension portion 413A is engaged with the peripheral edge of the through-hole 423 on the +Z side. This firmly connects the two circuit boards 410 and 420. Further, the engagement direction of the extension portion 413A with respect to the through-hole 423 corresponds to the direction in which the edge 410A of the circuit board 410 is pressed against the main board 9 (i.e., in the -Z direction) when the two circuit boards 410 and 420 are soldered to the main board 9 during reflow soldering. Therefore, the lift-off of the circuit board 410 as the antenna board from the main board 9 is advantageously limited. Furthermore, the conduction between the pattern (not shown) on the main board 9 and the antenna pattern (not shown) on the circuit board 410 can be advantageously ensured. [4-2. Effects]

[0057] In the fourth embodiment described above, the effects (1A), (1D) and (1E) of the first embodiment described above are achieved. [5. Further embodiments]

[0058] The embodiments for implementing the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiments, but may be modified in various other ways.

[0059] (5A) In each of the embodiments described above, the circuit boards constituting each pair of boards are connected to each other by the engagements of the through-hole(s) and the engaging portion(s). However, the connection between the circuit boards constituting the pair of boards is not limited to the above example. For example, the circuit boards constituting the pair of boards may be soldered to each other in the state where their edges abut each other. According to another example, a groove may be formed on an edge of the antenna board opposite to the edge adjacent to the main board, and an engaging portion formed on another circuit board may be engaged with the groove toward the main board. Even in such a case, it is possible to limit the antenna board from being lifted off the main board by the above-described engagement.

[0060] (5B) In each of the embodiments described above, the respective circuit boards are connected to each other such that the board thickness directions of the two circuit boards constituting the pair of boards are aligned in different directions by 90° around the Z axis (ie, the normal to the partial mounting surface 9A). However, the angle defined between the interconnected circuit boards is not limited to the angle described above. The circuit boards constituting the pair of boards can be connected to each other as long as their board thickness directions around the normal are different, and they can be connected to each other to define any angle, for example, an acute angle or an obtuse angle.

[0061] (5C) In each of the above-described embodiments, the THR-shaped electrode is mainly used, in which the electrode is provided by the above-described plugging into the motherboard. However, the shape of the electrode is not limited to the above-described example. An SMT-shaped electrode can be mainly used. Furthermore, the power supply of the antenna pattern can be realized by a cable (ie, an antenna).

[0062] (5D) In ​​each of the above-described embodiments, the protrusion(s) formed in the circuit board such as the antenna board are inserted into the through-hole(s) formed in the main board. However, the position where the protrusion is inserted is not limited to the above-described example. The protrusion formed on the circuit board such as the antenna board may be inserted into a recess (ie, a bottomed hole) formed in the main board.

[0063] (5E) In each of the embodiments described above, the electronic circuit is used for the in-vehicle antenna unit. However, the use of the electronic circuit is not limited to the example described above. The electronic circuit may be used for a portable device such as a tablet, or for a non-portable device.

[0064] (5F) In the embodiments described above, a plurality of functions provided by one component may be realized by a plurality of components, or a function provided by one component may be realized by a plurality of components. Alternatively, a plurality of functions provided by the plurality of components may be realized by a plurality of components, or a function provided by a plurality of components may be realized by a plurality of components. Further, a part of the components of the above embodiment(s) may be omitted. Moreover, at least a part of the structures of the above-described embodiment(s) may be added to a structure of another embodiment described above, or replaced with a structure of another embodiment described above.

[0065] Note that in each of the embodiments described above, the main board 9 corresponds to a first circuit board. Each of the circuit boards 10, 30, 50, 210, 310, 420 corresponds to a second circuit board. Each of the circuit boards 20, 40, 60, 220, 320, 410 corresponds to a third circuit board. Each of the through holes 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, and 103 corresponds to a hole. Of the through holes 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102 and 103, four through holes 91, 92, 93 and 94 correspond to position regulating sections.

Claims

[1] Electronic circuit (80), comprising: - a first printed circuit board (9); - a second circuit board (10, 30, 50, 210, 310, 420) mounted on the first circuit board (9) such that an edge (10A, 30A, 50A, 210A, 310A, 420A) of the second circuit board (10, 30, 50, 210, 310, 420) borders a part mounting surface (9A) of the first circuit board (9) on which a part (3, 5, 7) is mounted; - a third circuit board (20, 40, 60, 220, 320, 410) mounted on the first circuit board (9) such that an edge (20A, 40A, 60A, 220A, 410A) of the third circuit board (20, 40, 60, 220, 320, 410) borders on the partial mounting surface (9A), wherein - the second circuit board (10, 30, 50, 210, 310, 420) and the third circuit board (20, 40, 60, 220, 320, 410) are connected to each other in a state in which a board thickness direction of the second circuit board (10, 30, 50, 210, 310, 420) and a board thickness direction of the third circuit board (20, 40, 60, 220, 320, 410) are aligned in different directions from each other about a normal to the partial mounting surface (9A), and - at least one of the second circuit board (10, 30, 50, 210, 310, 420) and the third circuit board (20, 40, 60, 220, 320, 410) is provided with an antenna pattern (15, 35, 53, 54, 214), - a position regulating section (91, 92, 93, 94) provided in the first circuit board (9) for regulating a mounting position of the second circuit board (10) with respect to the first circuit board (9), - a projection (21) provided on one edge (20A) of the third circuit board (20), and - a hole (95) or a recess provided in the first circuit board (9), the hole (95) or the recess receiving the projection (21) when the second circuit board (10) and the third circuit board (20) are connected to each other and the second circuit board (10) is arranged at the mounting position regulated by the position regulating section (91, 92, 93, 94), wherein - the hole (95) or the recess has an inner diameter which is designed to increase depending on the distance from a connecting portion between the second circuit board (10) and the third circuit board (20). [2] Electronic circuit according to claim 1, wherein - the position regulating portion (91, 92, 93, 94) provided in the first circuit board (9) is either a hole (91, 92, 93, 94) or a recess in the first circuit board (9), and - the second circuit board (10, 30, 50) has a projection (11, 12, 13, 14, 31, 32, 33, 34, 51, 52) on one edge (10A, 30A, 50A) except at ends of the one edge (10A, 30A, 50A) to be received in the hole (91, 92, 93, 94) or the recess in the first circuit board (9). [3] The electronic circuit according to claim 1 or 2, further comprising a through-hole (18, 19, 423) passing through the second circuit board (10, 420) at a connecting portion between the second circuit board (10, 420) and the third circuit board (20, 410), and an engaging portion (22, 23, 413) provided in the third circuit board (20, 410) to pass through the through-hole (18, 19, 423) and to be engaged with the through-hole (18, 19, 423), the engaging portion (22, 23, 413) being soldered to the through-hole (18, 19, 423) in a state in which the engaging portion (22, 23, 413) is penetrated through the through-hole (18, 19, 423) passes through. [4] Electronic circuit according to claim 3, wherein - the second circuit board (10) is provided with the antenna pattern (15), - the engaging portion (22, 23) has an extending portion (22A, 23A) at a tip end, the extending portion (22A, 23A) extending in a direction toward the one edge (20A) of the third circuit board (20), and - the engaging portion (22, 23) is soldered to the through-hole (18, 19) in a state in which the extending portion (22A, 23A) is engaged with a peripheral edge of the through-hole (18, 19).

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