CN109196961B

CN109196961B - Connection structure of printed substrate

Info

Publication number: CN109196961B
Application number: CN201780031079.6A
Authority: CN
Inventors: 铃木规央; 田边刚; 佐佐木俊介; 西中佳郎
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2016-06-08
Filing date: 2017-05-29
Publication date: 2021-03-16
Anticipated expiration: 2037-05-29
Also published as: JPWO2017212964A1; WO2017212964A1; JP6659839B2; CN109196961A

Abstract

A printed circuit board connection structure (100) is provided with a first printed circuit board (1) and a second printed circuit board (2). A hole (10) is formed in the first printed circuit board (1) so as to extend from one first surface (1a) to the other first surface (1 b). The second printed circuit board (2) has one second surface (2a) and the other second surface (2b), and is inserted into the hole (10). The hole (10) extends in one direction on one first surface (1a) and the other first surface (1 b). The first electrode (3) of the first printed circuit board (1) and the second electrode (4) of the second printed circuit board (2) are electrically connected by a solder fillet (5). Insulating members (6, 7) are disposed on one second surface (2a) and the other second surface (2b) of the second printed circuit board (2). At least a part of the insulating members (6, 7) is disposed in the hole (10).

Description

Connection structure of printed substrate

Technical Field

The present invention relates to a printed circuit board connection structure, and more particularly, to a three-dimensional printed circuit board connection structure in which a second printed circuit board is inserted perpendicularly into a first printed circuit board provided with a hole, and electrodes of the two are electrically connected to each other by a fillet.

Background

As a connection structure of the first printed circuit board and the second printed circuit board fixed substantially perpendicularly thereto, for example, a structure disclosed in japanese patent application laid-open No. 2010-258190 (patent document 1) can be cited. In the connector of jp 2010-258190 a, a slit as a hole is provided in a first printed circuit board, a second printed circuit board is inserted into the slit, and electrodes of the two are electrically connected to each other by soldering.

Prior art documents

Patent document

Patent document 1: japanese patent application laid-open No. 2010-258190

Disclosure of Invention

Problems to be solved by the invention

Due to the problem of the processing accuracy of the substrate, a fitting tolerance must be provided between the width of the slit and the thickness of the second printed substrate. Due to this fitting tolerance, a gap is generated between the inner wall surface of the slit and the surface of the second printed circuit board at the time of soldering. Due to this gap, the second printed circuit board may be disposed at one side in the width direction without being disposed at the center portion in the width direction of the slit during soldering. In this case, the size of the solder fillet fixing the 2 printed boards is greatly different between the surface side of one side of the second printed board and the surface side of the other side opposite thereto. As a result, stress due to thermal strain concentrates on the smaller solder fillet on the surface side of one or the other of the second printed circuit board, and cracks may occur in the solder fillet. However, in japanese patent laid-open No. 2010-258190, no consideration is given to this problem.

The present invention has been made in view of the above problems, and an object thereof is to provide a printed circuit board connection structure having a structure in which a board inserted into a hole is joined without being deviated to one side in the width direction of the hole.

Means for solving the problems

The connection structure of the printed circuit board of the present invention includes a first printed circuit board and a second printed circuit board. The first printed circuit board has one and the other first surfaces, and is formed with a hole portion extending from the one first surface to the other first surface. The second printed circuit board has one and the other second surfaces and is inserted into the hole. The hole extends in one direction on the first surfaces of the one and the other. The first electrode of the first printed circuit board and the second electrode of the second printed circuit board are electrically connected by a solder fillet. An insulating member is disposed on the second surface of one and the other of the second printed circuit boards. At least a part of the insulating member is disposed in the hole.

Effects of the invention

According to the present invention, the insulating members on both surfaces of the second printed circuit board are disposed in the hole portion. Therefore, the difference in distance between the inner wall surface of the hole and the surface of the insulating member on one second surface side and the other second surface side of the second printed circuit board can be reduced as compared with the case where the insulating member is not provided. That is, the second printed circuit board inserted into the hole is joined without being biased to one side in the width direction of the hole, and concentration of stress caused by thermal strain to the solder fillet can be suppressed.

Drawings

Fig. 1 is a schematic perspective view of a printed circuit board connection structure according to the present invention.

Fig. 2 is a schematic plan view showing the structure of the first printed circuit board of the present invention.

Fig. 3 is a schematic plan view showing the structure of the second printed circuit board according to embodiment 1 and the positional relationship with the first printed circuit board connected thereto.

Fig. 4 is a schematic enlarged plan view of the second printed circuit board of fig. 3 clearly showing the range of the support portion included in the second printed circuit board of fig. 3.

Fig. 5 is a schematic cross-sectional view of a portion of the printed circuit board connection structure according to embodiment 1 taken along line a-a in fig. 1.

Fig. 6 is a schematic cross-sectional view of a portion of the connection structure of the printed circuit board of the comparative example along the line a-a in fig. 1.

Fig. 7 is a schematic perspective view showing the operation of the system of the printed circuit board in the step of forming the solder fillet.

Fig. 8 is a schematic cross-sectional view showing a molten solder supply mode when the second printed circuit board is disposed in the center portion in the width direction of the slit in embodiment 1 and when the second printed circuit board is thrown into the molten solder tank shown in fig. 7.

Fig. 9 is a schematic sectional view showing the dimensions of the respective members, particularly the inside of the slit 10 in fig. 5.

Fig. 10 is a schematic cross-sectional view showing a manner in which the second printed circuit board of the comparative example is connected to the first printed circuit board in an inclined state.

Fig. 11 is a schematic cross-sectional view showing a mode in which the second printed circuit board according to embodiment 1 is connected to the first printed circuit board in an inclined state.

Fig. 12 is a schematic cross-sectional view of a portion along the line a-a in fig. 1 of a first modification of the printed circuit board connection structure according to embodiment 1, which is different from fig. 5.

Fig. 13 is a schematic cross-sectional view of a portion along the line a-a in fig. 1 of a second modification of the printed circuit board connection structure according to embodiment 1, which is different from fig. 5.

Fig. 14 is a schematic cross-sectional view of a portion of the printed circuit board connection structure according to embodiment 2 taken along line a-a in fig. 1.

Fig. 15 is a schematic plan view showing the structure of the second printed circuit board and the positional relationship with the first printed circuit board connected thereto according to embodiment 2.

Fig. 16 is a schematic cross-sectional view of a portion of the printed circuit board connection structure according to embodiment 3 taken along line a-a in fig. 1.

Fig. 17 is a schematic plan view showing the structure of the second printed circuit board according to the first example of embodiment 3 and the positional relationship with the first printed circuit board connected thereto.

Fig. 18 is a schematic plan view of the second printed circuit board according to embodiment 1 (a) and a schematic sectional view of a portion of fig. 18(a) taken along line XVIIIB-xviib (B).

Fig. 19 is a schematic plan view of the second printed circuit board according to embodiment 3 (a) and a schematic cross-sectional view of a portion along the XIXB-XIXB line in fig. 19 (a).

Fig. 20 is a schematic plan view (a) showing the configuration of the second printed circuit board according to the second example of embodiment 3 and the positional relationship with the first printed circuit board connected thereto, and a schematic plan view (B) showing the configuration of the second printed circuit board according to the third example of embodiment 3 and the positional relationship with the first printed circuit board connected thereto.

Fig. 21 is a schematic plan view of a region XXI surrounded by a broken line in fig. 20(a) as viewed from the lower side in the Z direction.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment mode 1

Fig. 1 is a perspective view schematically showing a connection structure of a three-dimensional printed circuit board according to the present embodiment. For convenience of explanation, the X direction, the Y direction, and the Z direction are introduced. Fig. 2 is a schematic plan view of the first printed board constituting the connection structure of the printed board of fig. 1, as viewed from the lower side in the Z direction of fig. 1. Fig. 3 and 4 are schematic plan views of the second printed circuit board constituting the connection structure of the printed circuit board of fig. 1, viewed from the left side, i.e., the back side in the X direction. Fig. 5 and 9 are schematic sectional views of the embodiment taken along line a-a in fig. 1.

Referring to fig. 1 to 3, the printed circuit board connection structure of the present embodiment includes a main board 1 as a first printed circuit board and a standing board 2 as a second printed circuit board.

The main board 1 is a flat printed board having, for example, a rectangular shape in plan view, and has one first surface 1a and the other first surface 1b of the rectangular shape. Here, the first surface 1a is one of main surfaces that is a major surface excluding a dimension in the thickness direction when the main substrate 1 is viewed in plan. The other first surface 1b is a main surface on the opposite side of the one first surface 1 a. That is, for example, if one first surface 1a faces the Z-direction lower side, the other first surface 1b faces the Z-direction upper side opposite thereto. The main substrate 1 is formed with a slit 10 as a hole portion penetrating from one first surface 1a to the other first surface 1 b.

For example, as shown in fig. 2, the slit 10 may include a slit 10a, a slit 10b, and a slit 10c formed at intervals in the Y direction, which is a direction along the long side when the main substrate 1 is viewed in a plan view. The

slits

10a, 10b, 10c are arranged in this order in the Y direction. The

slits

10a, 10b, and 10c each have a rectangular shape in plan view, and are configured to be able to be inserted into a part of the standing substrate 2. The

slits

10a, 10b, 10c extend in one direction on one first surface 1a and the other first surface 1 b. In fig. 2, the

slits

10a, 10b, and 10c all extend along the Y direction, and the slit 10b at the center in the Y direction extends the longest. However, it is not limited to such a manner.

The upright substrate 2 is a flat printed substrate and has one second surface 2a and the other second surface 2 b. Here, the second surface 2a is one of main surfaces that is a main surface excluding a dimension in the thickness direction when the standing substrate 2 is viewed in plan. The other second surface 2b is a main surface on the opposite side of the one second surface 2 a. A region where a part of the substrate 2 stands is formed as a support portion 11.

Referring to fig. 3 and 4, for example, as shown in fig. 3, the support portion 11 is a region adjacent to the end surface on the lower side in the Z direction extending along the Y direction, which is the longitudinal direction thereof. In other words, the support portion 11 is a portion of the raised substrate 2 located on the side of the first surface 1a, i.e., on the lower side in the Z direction, with respect to the other first surface 1b of the main substrate 1 in the state of fig. 1 where the raised substrate 2 is inserted into the slit 10 of the main substrate 1. The standing substrate 2 may include

support portions

11a, 11b, and 11c formed at intervals in the Y direction in the support portion 11. The

support portions

11a, 11b, and 11c are arranged in this order in the Y direction. Further, a notch 12 for raising the substrate 2 is provided in a region between the support portion 11a and the support portion 11b and a region between the support portion 11b and the support portion 11 c. Therefore, the standing substrate 2 has a rectangular shape in a plan view if the notch 12 is filled. As shown in fig. 4 in particular, the support portion 11 is a region having a position coordinate in the Z direction equal to the region where the notch 12 is formed.

The support portion 11a, the support portion 11b, and the support portion 11c can be inserted into the

slits

10a, 10b, and 10c, respectively. Thereby, a part of the standing substrate 2 is inserted into the slit 10. Therefore, in fig. 3, the

support portions

11a, 11b, and 11c all extend along the Y direction, and the support portion 11b at the center in the Y direction extends the longest. However, it is not limited to such a manner. The support portion 11 extending in the Z direction penetrates through the slit 10 of the main board 1. Thus, for example, a three-dimensional printed circuit board connection structure in which the main circuit board 1 and the rising circuit board 2 intersect each other is formed such that one first surface 1a and one second surface 2a are substantially orthogonal to each other.

Referring again to fig. 2, the main substrate electrode 3 as a first electrode is formed on one first surface 1a of the main substrate 1 in a region adjacent to the slit 10. Referring again to fig. 3, an upright substrate electrode 4 as a second electrode is formed on one first surface 2a of the upright substrate 2 in a region adjacent to the slit 10 when the first surface is inserted into the slit 10.

In a state where the rising substrate 2 is inserted into the slit 10, the rising substrate electrode 4 is formed below the other first surface 1b and the one first surface 1a of the main substrate 1 indicated by the broken lines in fig. 3. That is, the rising substrate electrode 4 is formed on the support portion 11 of the rising substrate 2. When the raised substrate electrode 4 is inserted into the slit 10, in fig. 2, the plurality of main substrate electrodes 3 are formed with a space in the Y direction only in the region planarly adjacent to the slit 10b of the 3 slits 10, but the present invention is not limited thereto, and the main substrate electrodes 3 may be similarly formed in the regions planarly adjacent to the

slits

10a and 10 c. In fig. 3, a plurality of the rising substrate electrodes 4 are formed with a space in the Y direction only in the support portion 11b of the 3 support portions 11, but the present invention is not limited to this, and the rising substrate electrodes 4 may be formed similarly in the

support portions

11a and 11 c. Although not shown in fig. 3, the standing substrate electrode 4 is also formed on the second surface 2b of the standing substrate 2 in the same manner as the second surface 2 a.

Referring to fig. 5, in the printed circuit board connection structure 100 of the present embodiment, the main substrate electrodes 3 on one first surface 1a of the main substrate 1 and the raised substrate electrodes 4 on one second surface 2a and the other second surface 2b of the raised substrate 2, which are particularly disposed on the lower side in the Z direction than the main substrate 1, are connected by solder fillets 5. The solder fillets 5 electrically connect the main substrate electrodes 3 and the upright substrate electrodes 4, and mechanically connect the main substrate 1 and the upright substrate 2. That is, the solder fillets 5 are formed on both the one second surface 2a and the other second surface 2b of the raised substrate 2.

Referring to fig. 2, 3, and 5, in the printed circuit board connection structure 100 according to the present embodiment, a resist film 6 is formed so as to cover the main circuit board electrode 3 on one first surface 1 a. Further, a resist film 6 is formed so as to cover the raised substrate electrodes 4 on the one second surface 2a and the other second surface 2 b. The resist film 6 may be formed as a pattern only in the region adjacent to the slit 10, but may be formed so as to cover substantially the entire surface of the one first surface 1a, the one second surface 2a, and the other second surface 2b except for the region where the main substrate electrode 3 and the raised substrate electrode 4 are exposed for connection by the solder fillet 5. That is, the resist film 6 is an insulating film formed on the main substrate 1 and the raised substrate 2 from the viewpoint of not exposing the main substrate electrode 3 and the raised substrate electrode 4, which electrically connect the elements formed on these substrates, to the outside of a desired region. Thereafter, the region where the main substrate electrode 3 and the raised substrate electrode 4 are exposed without being covered with an insulating member such as the resist film 6 is defined as a region where the main substrate electrode 3 and the raised substrate electrode 4 are formed.

Referring again to fig. 3 and 5, a screen pattern 7 made of an insulating material containing, for example, an acrylic resin, an epoxy resin, or the like as a main component is formed in a partial region on one second surface 2a and the other second surface 2b of the raised substrate 2. The screen pattern 7 is formed so as to cover at least a part of the surface of the resist film 6 formed so as to cover the raised substrate electrodes 4. Specifically, the screen pattern 7 is formed so as to cover the lowermost region in the Z direction of the resist film 6 of the raised substrate 2. That is, the screen pattern 7 is formed so as to overlap the resist film 6, and a portion where the screen pattern 7 overlaps the resist film 6 is disposed as an insulating member.

At least a portion of the insulating member is disposed within the slot 10. That is, in fig. 5, a region of about half of the lower side of the portion of the insulating member where the screen pattern 7 and the resist film 6 overlap is disposed in the slit 10. One end surface of the insulating member on the first surface 1a side is disposed in the slit 10. That is, in fig. 5, the lower end surface 6e, which is the lower end surface on the Z direction side, which is the first surface 1a side of the resist film 6, and the lower end surface 7e, which is the end surface on the first surface 1a side of the screen pattern 7, are arranged in the vicinity of the middle between the first surface 1a and the first surface 1b in the slit 10. Referring again to fig. 3, the screen pattern 7 has a belt-like shape linearly extending along the Y direction, which is one direction in which the slits 10 extend. In fig. 3, the screen patterns 7 are arranged in only 1 row in the Z direction, but 2 or more rows of the screen patterns 7 may be arranged with a space therebetween in the Z direction.

Here, the resist film 6 and the screen pattern 7, which are insulating members for insulating the raised substrate 2, are basically formed by a generally known method. Specifically, a material constituting the standing substrate 2 is cut into a flat plate shape, and a pattern of, for example, a copper foil is formed on one second surface 2a and the other second surface 2b by a generally known photo-lithography technique and an etching technique. A resist solution is applied to the pattern of the copper foil, and the resist solution is partially formed as a resist pattern, i.e., a resist film 6, by a photo-lithography technique. Next, a screen pattern 7 is formed on the surface of the resist film 6 by screen printing. The method of forming the resist film 6 on the main substrate 1 is basically the same as described above, and therefore, detailed description thereof is omitted.

Next, a comparative example of the present embodiment will be described, and the operational effects of the present embodiment will be described.

Referring to fig. 6, in the connection structure 900 of the printed circuit board of the comparative example, due to the problem of the processing accuracy of the substrate, a fitting tolerance is inevitably provided between the width of the slit 10 in the X direction and the support portion 11 of the standing substrate 2. That is, a gap is formed between the inner wall surface of the slit 10 and the surface of the upright substrate 2 (including the surface of the upright substrate electrode 4). In this case, when the support portion 11 is inserted into the slit 10, the support portion 11 of the raised substrate 2 may be disposed on one side in the X direction instead of being disposed at the center portion in the X direction of the slit 10. For example, in fig. 6, the standing substrate 2 is arranged to be shifted to the right side from the center portion thereof in the X direction of the slit 10.

If the main substrate 1 and the raised substrate 2 are connected by the solder fillets 5 in a state where the raised substrate 2 is biased toward one side as shown in fig. 6, there is a possibility that the size and shape of the connected solder fillets 5 may be greatly different between the side of the one second surface 2a of the raised substrate 2 and the side of the other second surface 2 b. This case will be described with reference to fig. 7.

Referring to fig. 7, in the step of forming the solder fillet 5, the slit 10 of the main substrate 1 is inserted into the support portion 11 of the upright substrate 2, and is fed into the molten solder bath while being moved in a direction along, for example, the Y direction which is the longitudinal direction of each substrate. Therefore, by moving the substrates in the Y direction, the molten solder is supplied from the lower side of the main substrate 1, i.e., the first surface 1a side, to the upper side of the main substrate electrode 3 and the upper side of the rising substrate electrode 4, and the solder fillet 5 is formed so as to connect the upper side of the main substrate electrode 3 and the upper side of the rising substrate electrode 4. By disposing the rising substrate electrode 4 below the one first surface 1a, which is the support portion 11, the solder fillet 5 connecting the rising substrate electrode 4 and the main substrate electrode 3 can be more easily formed.

In this case, when the entire upright substrate 2 is not linearly symmetrical with the one side shifted as shown in fig. 6, when the entire system is put into the molten solder bath as shown in fig. 7, the molten solder is supplied in a physically different manner between the one second surface 2a side and the other second surface 2b side. Therefore, in this case, the solder fillets 5 on the one second surface 2a side and the other second surface 2b side have large differences in size and shape. If the sizes of the solder fillets 5 are not uniform, stress due to thermal strain concentrates on the smaller one of the one second surface 2a side and the other second surface 2b side, and cracks may form in the solder fillets 5.

In addition, as shown in fig. 6, a manufacturing variation between the main substrate 1 and the raised substrate 2 may be originally considered as a cause of the raised substrate 2 being shifted to one side. That is, when the gap, which is the tolerance of the fit between the slit 10 and the upright substrate 2, becomes very large due to manufacturing variations, the distance between the main substrate electrode 3 and the upright substrate electrode 4 becomes very large, and therefore, the solder fillet 5 connecting the main substrate electrode 3 and the upright substrate electrode 4 may not be formed by the method of fig. 7. On the other hand, if the gap, which is the fitting tolerance, is 0 or a negative value (the thickness of the standing substrate is larger than the width of the slit) due to manufacturing variations, the support portion 11 cannot be inserted into the slit 10, and the inner wall surface of the slit 10 needs to be cut.

Therefore, referring to fig. 8, if the distance between the uppermost surface on the one second surface 2a side of the standing substrate 2 and the inner wall surface of the slit 10 is substantially equal to the distance between the uppermost surface on the other second surface 2b side and the inner wall surface of the slit 10, the entire system shown in the figure is line-symmetric about the standing substrate 2 as the axis C. At this time, the manner of supplying molten solder 50 to the one second surface 2a side shown by arrow F in the figure is physically equivalent to the manner of supplying molten solder 50 to the other second surface 2b side. Therefore, the sizes and shapes of the solder fillets 5 generated by the solidification of the molten solder 50 on the one second surface 2a side and the other second surface 2b side are substantially equal. Therefore, the stress due to the thermal strain applied to the solder fillet 5 on the one second surface 2a side and the solder fillet 5 on the other second surface 2b side can be uniformly dispersed, and the generation of cracks in the solder fillet 5 can be suppressed.

In order to provide the standing substrate 2 in line symmetry with respect to the slit 10, as shown in fig. 8, a resist film 6 and a screen pattern 7 as an insulating member are disposed on one second surface 2a and the other second surface 2b of the standing substrate 2, and at least a part of the resist film and the screen pattern are disposed in the slit 10. More specifically, one end surface of the insulating member on the first surface 1a side is disposed in the slit 10. Thus, even when the width of the slit 10 is larger than the width of the rising substrate 2 due to, for example, manufacturing variations, the distance between the rising substrate electrode 4 and the inner wall surface of the slit 10 can be secured at least by the thickness of the insulating member on both the one second surface 2a side and the other second surface 2b side.

Therefore, for example, as compared with the case where the resist film 6 and the screen pattern 7 are not provided, the difference in distance between the inner wall surfaces of the slits 10 and the insulating member between the one second surface 2a side and the other second surface 2b side of the raised substrate 2 can be reduced. Therefore, the support portion 11 can be prevented from being extremely biased to one side in the slit 10, and can be configured to be close to the state in which the standing substrate 2 is disposed at the center portion as shown in fig. 8. On the other hand, even when the width of the slit 10 is substantially equal to the width of the raised substrate 2 or smaller than the width of the raised substrate 2, the screen pattern 7 can be cut off at the edge portion of the slit 10 and inserted in a state where the slit 10 is fitted into the raised substrate 2 as much as possible, and therefore, the raised substrate 2 can be inserted into the slit 10 without cutting the slit 10. Since the chips of the screen pattern 7 generated at this time are nonconductive, the yield of the printed circuit board connection structure 100 is not reduced even if the chips are scattered.

Fig. 9 shows the dimensions of the portions in the portion where the slit 10 is inserted with the raised substrate 2. Referring to fig. 9, W represents the width of slit 10 in the X direction in fig. 1, and t represents the thickness of raised substrate 2, i.e., the dimension of raised substrate 2 in the X direction in fig. 9. Here, the thickness t of the standing substrate 2 is set to include the thickness of the standing substrate electrode 4 formed on one second surface 2a and the other second surface 2 b. Further, the distance between the surface of the raised substrate electrode 4 on the one second surface 2a and the inner wall surface of the slit 10 is d1, and the distance between the surface of the raised substrate electrode 4 on the other second surface 2b and the inner wall surface of the slit 10 is d 2. The thickness of each of the resist films 6 on the one second surface 2a and the other second surface 2b is t1, and the thickness of the screen pattern 7 is t 2.

In this case, the sum of the values of d1 and d2 is preferably 0mm or more and 0.5mm or less, and the difference between d1 and d2 is preferably as small as possible (more preferably 0). The sum of the values of t1 and t2 on both sides of the raised substrate 2 is preferably 0mm or more and 0.5mm or less in the finished product, but the sum may exceed 0.5mm and be 0.7mm or less before the excess thickness of the screen pattern 7 is shaved off as described above. The sum of the values of t1 and t2 is shown here because consideration is given to the case where only one of the resist film 6 and the screen pattern 7 is formed as described later.

Next, fig. 10 and 11 show a manner in which the rising substrates 2 are not connected substantially perpendicularly to the main substrate 1 but the rising substrates 2 are connected in an inclined state, in each of the comparative example and the present embodiment. Referring to fig. 10, in the case where the resist film 6 and the screen pattern 7 as the insulating members are not disposed inside the slit 10 as in the connection structure 901 of the printed circuit board of the comparative example, if the width of the slit 10 is extremely larger than the thickness of the raised substrate 2, the raised substrate 2 may be greatly inclined with respect to the direction perpendicular to the main substrate 1. However, referring to fig. 11, if the resist film 6 and the screen pattern 7 as the insulating members are disposed inside the slit 10 as in the connection structure 101 of the printed circuit board according to the present embodiment, the insulating members such as the screen pattern 7 immediately contact the inner wall surface of the slit 10 when the upright substrate 2 is tilted. Therefore, compared to the case of fig. 10, the tilt of the standing substrate 2 can be suppressed. If the tilt of the riser substrate 2 is suppressed, the difference in size and shape between the solder fillets 5 on the one second surface 2a side and the other second surface 2b side of the riser substrate 2 can be reduced, and the concentration of stress due to thermal strain can be suppressed.

As the insulating member, as shown in fig. 5 and 8, both the resist film 6 and the screen pattern 7 covering at least a part of the surface thereof may be stacked. However, referring to fig. 12, in the printed circuit board connection structure 102 of the present embodiment, the insulating member may be configured by only the resist film 6. Alternatively, referring to fig. 13, in the connection structure 103 of the printed circuit board according to the present embodiment, the insulating member may be configured by only the screen pattern 7. That is, the insulating member may be constituted by at least one of the resist film 6 and the screen pattern 7.

The insulating member provides a thickness for securing a distance between the rising substrate electrode 4 and the inner wall surface of the slit 10 and suppressing deflection of the rising substrate 2. Therefore, for example, if the sum of the thickness t1 and the thickness t2 shown in fig. 9 is a sufficiently large value, the effect of the present embodiment can be achieved even if only one of the resist film 6 and the screen pattern 7 or even if the other insulating material is used. The other insulating material is a functional treatment film such as a coating agent for moisture-proof treatment containing an acrylic resin, a urethane resin, a polyurethane resin, a polyolefin resin, or the like as a main component. Alternatively, the other insulating material may be an insulating tape mainly composed of polyimide resin or polyethylene resin. Therefore, in any of the configurations of fig. 12 and 13, the solder fillets 5 can be formed uniformly on both sides of the rising substrate 2, as in the configuration of fig. 5.

However, even if a laminated structure of the resist film 6 and the screen pattern 7 is used as the insulating member as shown in fig. 5, the resist film 6 and the screen pattern 7 can be formed simultaneously with the resist film 6 and the screen pattern 7 formed for another purpose in the region other than the inside of the slit 10, and therefore, a separate insulating member forming step is not required, and the structure of fig. 5 can be easily formed. The resist film 6 and the screen pattern 7 may be coated or printed in two or more layers (three or more layers) to secure a thickness.

In addition, by forming the screen pattern 7 in a band shape linearly extending along the Y direction in which the slits 10 extend as in the present embodiment, the amount of the screen pattern 7 appearing when hidden from the inside of the slits 10 when the raised substrate 2 is fitted to the main substrate 1 can be easily measured by visual inspection or sensory inspection. This makes it possible to easily determine whether or not the warpage of the main substrate 1 occurs or whether or not the raised substrate 2 floats upward in the Z direction with respect to the main substrate 1.

The screen pattern 7 is formed as 1 stripe pattern extending in the Y direction as described above, but may be formed as two or more stripe patterns formed with a space therebetween in the Z direction, for example. When the thickness of the main substrate 1 is large and the dimension of the slits 10 in the Z direction is large, or when the screen pattern 7 can be printed more finely, the screen pattern 7 may be formed as two or more patterns.

In addition, in the present embodiment, it is more preferable to adjust the screen pattern 7 and, as the case may be, the pattern width of the resist film 6. Thus, in the molten solder 50 supplying step shown in fig. 8, the amount of molten solder 50 supplied to the region between the support portion 11 of the upright substrate 2 and the slit 10 of the main substrate 1 can be kept constant, and the strength of the joint portion between the main substrate electrode 3 and the upright substrate electrode 4, which is formed by the solder fillet 5, can be controlled to an arbitrary value. In addition, since the amount of solder forming the solder fillet 5 can be controlled to be constant, the occurrence of solder bridges between the plurality of main substrate electrodes 3 and between the plurality of upright substrate electrodes 4 adjacent to each other in the Y direction can be suppressed.

Embodiment mode 2

Fig. 14 corresponds to fig. 5 of embodiment 1, and fig. 15 corresponds to fig. 3 of embodiment 1. Referring to fig. 14 and 15, since the printed circuit board connection structure 200 according to the present embodiment basically has the same structure as the printed circuit board connection structure 100 according to embodiment 1, the same reference numerals are given to the same components, and description thereof will not be repeated as long as functions, effects, and the like are the same. The printed circuit board connection structure 200 of the present embodiment has the resist film 6 and the screen pattern 7 as the insulating member, similarly to the printed circuit board connection structure 100.

However, in the present embodiment, the end surface of the insulating member on the first surface 1a side is disposed at a position overlapping with the first surface 1a of the slit 10. That is, the lower end surface 6e of the resist film 6 and the lower end surface 7e of the screen pattern 7 are disposed so that the position in the Z direction is substantially equal to the one first surface 1a of the main substrate 1, that is, so as to be aligned with the one first surface 1 a. That is, in the present embodiment, the resist film 6 and the screen pattern 7 are disposed over the entire region in the Z direction inside the slit 10. In this case as well, the raised substrate electrodes 4 are formed below the other first surface 1b and the one first surface 1a of the main substrate 1 shown by the broken lines in fig. 3 in a state where the raised substrate 2 is inserted into the slit 10. In this regard, the present embodiment is different from embodiment 1 in which the lower end surface 6e and the lower end surface 7e are disposed in the vicinity of the middle between one first surface 1a and the other first surface 1b in the slit 10.

Next, the operation and effect of the present embodiment will be described. This embodiment has the following operational effects in addition to the same operational effects as embodiment 1.

In the present embodiment, the lower end surface 6e and the lower end surface 7e are disposed at the lowermost portion of the slit 10 overlapping the one first surface 1a, and therefore, even when the pitch between the plurality of the upright substrate electrodes 4 and the main substrate electrodes 3 arranged at intervals in the Y direction is narrow, solder bridges are not formed between the pair of the upright substrate electrodes 4 adjacent to each other and the pair of the main substrate electrodes 3 adjacent to each other, and the upright substrate electrodes 4 and the main substrate electrodes 3 can be joined by the solder fillets 5. Even when the solder bridge is formed, the solder fillet 5 does not enter the inside of the slit 10, and the presence or absence of the solder bridge can be easily determined visually because the solder bridge is highly visually confirmed. Further, according to the present embodiment, for example, by visually checking that the lower end surface 7e of the screen pattern 7 protrudes downward in the Z direction than the slits 10, it is possible to easily determine the presence or absence of the warpage of the main board 1.

Embodiment 3

Fig. 16 corresponds to fig. 5 of embodiment 1, and fig. 17 corresponds to fig. 3 of embodiment 1. Referring to fig. 16 and 17, since the printed circuit board connection structure 300 of the present embodiment basically has the same structure as the printed circuit

board connection structures

100 and 200 of

embodiments

1 and 2, the same reference numerals are given to the same components, and description thereof will not be repeated as long as functions, effects, and the like are the same. The printed circuit board connection structure 300 of the present embodiment has the resist film 6 and the screen pattern 7 as the insulating member, similarly to the printed circuit

board connection structures

100 and 200.

However, in the present embodiment, a plurality of screen patterns 7 are arranged along the Y direction, which is one direction of the slits 10, with an interval therebetween. Specifically, the screen pattern 7 has a circular shape in a plan view shown in fig. 17, for example, and a plurality of screen patterns are arranged with a space therebetween. The resist film 6 is stacked on the lower layer of the screen pattern 7 in the same manner as in the other embodiments, and the raised substrate electrode 4 exposed at the lowermost portion in the Z direction of the raised substrate 2 is formed on the lower layer in the same manner as in the other embodiments. A plurality of the screen patterns 7 are arranged to have a circular shape at the same position in the Y direction as the position where the raised substrate electrode 4 is exposed, and substantially immediately above the position where the raised substrate electrode 4 is exposed in the Z direction. In this regard, the present embodiment is structurally different from

embodiments

1 and 2 in which the screen pattern 7 has a strip-like shape linearly extending along the Y direction, which is one direction in which the slits 10 extend.

In fig. 16 and 17, the uppermost portion of the screen pattern 7 in the Z direction is disposed at a position overlapping the other first surface 1b of the main substrate 1, and the lowermost portion in the Z direction is disposed at a position overlapping the one first surface 1a of the main substrate 1. That is, in the present embodiment, the screen pattern 7 is arranged over the entire region in the Z direction inside the slit 10. Further, the lower end surface 7e of the screen pattern 7 and the lower end surface 6e of the resist film 6 are arranged at positions overlapping with the first surface 1a of the slit 10, as in embodiment 2. However, the present embodiment is not limited to this embodiment, and the lower end surface 7e of the circular screen pattern 7 may be disposed in a region near the middle between the first surface 1a and the first surface 1b in the slit 10, as in embodiment 1. The screen pattern 7 may be partially exposed to the region on the Z direction upper side of the other first surface 1 b. The screen patterns 7 are arranged in the same number as the number of the upright substrate electrodes 4 in the Y direction at the same width and interval as the width of the upright substrate electrodes 4, but not limited to this, and may be arranged in a different number from the number of the upright substrate electrodes 4 at a different width and interval from the upright substrate electrodes 4.

In fig. 17, the screen pattern 7 has a circular shape in a plan view, but is not limited thereto, and may have any shape such as a rectangular shape or an elliptical shape. In fig. 17, the screen patterns 7 are arranged in only 1 row in the Z direction. However, particularly when the thickness of the main substrate 1 is large, or when the size of the screen pattern 7 in a plan view can be printed smaller, 2 or more lines of the screen patterns 7 may be arranged at intervals from each other in the Z direction.

Next, the operation and effect of the present embodiment will be described. This embodiment has the following operational effects in addition to the operational effects similar to those of

embodiments

1 and 2.

Fig. 18 shows a cross-sectional shape of the belt-shaped screen pattern 7 when formed as in embodiment 1. Fig. 19 shows a cross-sectional shape of the screen pattern 7 divided into a plurality of parts as in the present embodiment.

Referring to fig. 18, when the screen pattern 7 is printed in a band shape as shown in fig. 18(a), the dimension in the Y direction, which is the extending direction thereof, is large, and particularly, the distance from the edge portion of the screen pattern 7 in the Y direction is extremely large at the center portion in the Y direction thereof, and the force for supporting the surface thereof is weaker than the force in the vicinity of the edge portion. Therefore, as shown in the sectional view of fig. 18(B), when the resin material is scraped off by, for example, a squeegee at the time of printing of the belt-shaped screen pattern 7, a concave portion 7d is formed at the central portion of the screen pattern 7. In fig. 18(B), the illustration of the rising substrate electrode 4 is omitted from the viewpoint of simplification of the drawing, but the resist film 6 is disposed so as to cover the rising substrate electrode 4 as in the other drawings. This is also the case in fig. 19(B) below.

Referring to fig. 19, on the other hand, when a plurality of, for example, circular screen patterns 7 are formed at intervals in the Y direction as shown in fig. 19(a), the distance from the edge of the screen pattern 7 is small in any portion of the screen pattern 7. That is, in fig. 19, the force supporting the surface of the screen pattern 7 is stronger than that in fig. 18. Therefore, as shown in the sectional view of fig. 19(B), when the resin material is scraped off by, for example, a squeegee at the time of printing of the belt-shaped screen pattern 7, the concave portion 7d is no longer formed at the central portion of the screen pattern 7.

Therefore, according to the present embodiment, the thickness of the screen pattern 7 in the X direction is substantially uniform over a wide range thereof, as compared with embodiment 1. That is, in the present embodiment, when the standing substrate 2 is inserted into the slit 10 of the main substrate 1 and the screen pattern 7 is arranged in the slit 10, the accuracy of the fit tolerance between the inner wall surface of the slit 10 and the screen pattern 7 can be improved as compared with embodiment 1. That is, in the present embodiment, the thickness of the screen pattern 7 can be controlled with higher accuracy than in embodiment 1.

In addition, in the case where a plurality of small circular screen patterns 7 are formed as in the present embodiment, the amount of application of the screen patterns 7 is reduced as compared with the case where continuous belt-shaped screen patterns 7 are formed. Therefore, the insertion pressure when inserting the raised substrate 2 on which the screen pattern 7 is formed into the slit 10 of the main substrate 1 can be reduced.

Fig. 20(a) and (B) show a modification of fig. 17, and both correspond to fig. 3 of embodiment 1, as in fig. 17. Referring to fig. 20(a) and (B), these are basically the same configurations as those of fig. 17, and the description thereof will not be repeated. However, in fig. 20(a) and (B), the screen pattern 7 is disposed at a position different from the position where the raised substrate electrodes 4 are exposed in the Y direction, that is, at a position sandwiched between regions where the plurality of raised substrate electrodes 4 are exposed with a space therebetween in the Y direction. Thus, the upright substrate electrodes 4 exposed in the Y direction are alternately arranged with the screen pattern 7. In this regard, fig. 20(a) and (B) are different in structure from fig. 17 in which the screen pattern 7 is disposed at the same position in the Y direction as the position where the raised substrate electrode 4 is exposed.

The screen pattern 7 may have a rectangular planar shape as shown in fig. 20(a), but the screen pattern 7 may have a circular or elliptical planar shape as shown in fig. 20 (B).

Fig. 21 is a schematic plan view of a region XXI surrounded by a broken line in fig. 20(a) as viewed from the lower side in the Z direction, which is the same direction as fig. 2. Referring to fig. 21, by disposing the screen pattern 7 between the exposed portions of the upright substrate electrodes 4 adjacent in the Y direction as shown in fig. 20, the area of the exposed portions of the upright substrate electrodes 4 can be increased as compared with the case where the screen pattern 7 is disposed on the upper side in the Z direction at the same position as the exposed portions of the upright substrate electrodes 4 in the Y direction as shown in fig. 17. Therefore, the amount of solder forming the solder fillet 5 can be increased. Therefore, the strength of the joint portion between the main substrate electrode 3 and the rising substrate electrode 4, which is formed by the solder fillet 5, can be increased. Referring to fig. 21, the exposed portions of the pair of the raised substrate electrodes 4 adjacent to each other in the Y direction are physically separated by the screen pattern 7. This can suppress the occurrence of solder bridges in the slit 10.

In fig. 21, the sum of the thicknesses of the raised substrate electrodes 4 on the front surface 2a side and the front surface 2b side is preferably 0.5mm or less obtained by subtracting the sum of the thicknesses of the resist films 6 on the front surface 2a side and the front surface 2b side of the raised substrate 2 from the sum of the thicknesses of the screen patterns 7 on the front surface 2a side and the front surface 2b side.

The features described in the above-described embodiments (including the examples) can be applied in combination as appropriate within a range not technically contradictory to the present invention.

The embodiments disclosed herein are to be considered as illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Description of the reference numerals

1a main substrate, 1a first surface, 1b first surface, 2 standing substrate, 2a second surface, 2b second surface, 3 main substrate electrode, 4 standing substrate electrode, 5 solder fillet, 6 resist film, 6e, 7e lower end face, 7 screen pattern, 7d recess, 10a, 10b, 10c slit, 11a, 11b, 11c support, 12 notch, 50 molten solder, 100, 101, 102, 103, 200, 300, 900, 901 printed substrate.

Claims

1. A printed circuit board connection structure, comprising:

a first printed circuit board having one first surface and the other first surface opposite to the one first surface, and formed with a hole portion reaching the other first surface from the one first surface; and

a second printed board having one second surface and the other second surface opposite to the one second surface, and inserted into the hole,

the hole extends in a first direction on first surfaces of the one and the other,

a plurality of first electrodes disposed in a region adjacent to the hole portion on the first surface of the first printed circuit board and a plurality of second electrodes disposed in a region adjacent to the hole portion on the second surface of the first printed circuit board and the second printed circuit board are electrically connected by solder fillets,

an insulating member is disposed on a second surface of the one and the other of the second printed circuit boards,

an end surface of the insulating member on the first surface side is disposed in the hole,

the insulating member includes a resist film and a resin material on the resist film,

the second printed circuit board inserted into the hole includes a support portion located on the one first surface side of the other first surface,

the resist film is disposed on the other first surface side of the support portion at a position overlapping with the plurality of second electrodes on the one and other second surfaces and at a position sandwiched between a pair of the second electrodes adjacent to each other on the one and other second surfaces,

a plurality of the resin materials are arranged at positions overlapping with the plurality of second electrodes on the second surfaces of the one and the other, respectively, so as to be spaced apart from each other along the first direction of the hole,

the sum of the thicknesses of the second printed circuit board, the resist film, and the resin material is equal to or less than a width dimension of the hole portion in the first direction.

2. The connection structure of printed substrates according to claim 1,

the second electrode is disposed on the support portion.

3. A printed circuit board connection structure, comprising:

an insulating member is disposed at a position sandwiched between a pair of the second electrodes adjacent to each other on the second surface of the one and the other of the second printed circuit boards,

at least a part of the insulating member is disposed in the hole portion,

the resin material is arranged at a plurality of positions between a pair of the second electrodes adjacent to each other on the second surfaces of the one and the other, respectively, and a plurality of the resin materials are arranged along the first direction of the hole portion with a space therebetween,

4. The connection structure of printed substrates according to claim 3,

the insulating member is disposed at a position sandwiched between regions where the plurality of second electrodes are exposed with a space therebetween.