JP2006245562A - Connection structure connecting flexible substrate to main substrate, and connecting method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure that connects a flexible substrate to a main substrate with sufficient strength without introducing a complicated working and a method therefor. <P>SOLUTION: The main substrate 100 is provided with a wiring pattern 101 using its surface or internal layer. A wiring pattern 2 that connects a signal line or a power line of the substrate 100 to an external circuit is formed on the flexible substrate 1. A connection terminal 3 connected to a corresponding wiring pattern 2 is formed at an end of the substrate 1. Throughholes 4 are formed between the wiring patterns 2. A potting resin 11 is potted at the holes 4 and in the vicinity thereof. The resin 11 bonds the substrate 100 and the substrate 1 as the resin is cured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a connection structure for connecting a flexible substrate to a main substrate having a wiring pattern, and a connection method thereof.

  Conventionally, a flexible printed circuit (FPC) has been used to connect a signal line or a power line on a main board having a wiring pattern to an external circuit. The flexible substrate is generally a sheet-like flexible substrate, and a wiring pattern is formed on the surface or inner layer thereof.

  When the main board and the flexible board are electrically connected, a part of the wiring pattern formed on the main board and a part of the corresponding wiring pattern formed on the flexible board are electrically connected by solder or the like. Connected. However, if these substrates are connected only by solder or the like, the strength is not sufficient and the connecting portion may be peeled off. Thus, proposals have been made to reinforce the connection between the main board and the flexible board.

  In Patent Document 1, as shown in FIG. 8A and a side view thereof, FIG. 8B, a resin potting that acts as an adhesive to reinforce the connection between the main substrate 100 and the flexible substrate 110. Has been made. As a result, when the product including the main substrate 100 and the flexible substrate 110 is assembled or used, the peeling stress at the joint portion is received by the potting resin, and the stress on the solder connection portion is alleviated.

  In Patent Document 2, as shown in FIG. 9, the main substrate 100 and the flexible substrate 110 are connected. A connection copper hull 121 is formed on the upper surface of the main substrate 100, and a resist 122 is further provided on the upper surface. A wiring pattern 123 and a cover film 124 are formed on the flexible substrate 110. The connection copper hull 121 and the wiring pattern 123 are connected by a pressure connection portion 125 made of thick-plated solder. And the adhesive agent 126 is apply | coated to the contact surface of the main board | substrate 100 and the flexible substrate 110, and the connection part is reinforced.

As another structure, a method of fixing the main substrate and the flexible substrate using rivets or the like has been proposed.
Japanese Utility Model Publication No. 62-73576 (FIGS. 3 and 4) JP-A-7-38253 (FIGS. 3 and 4)

  In the structure described in Patent Document 1, the bonding effect by the potting resin is obtained in the end portion of the resin potting area with respect to the short direction of the flexible substrate 110 (the portion surrounded by the broken line in FIG. 8A). Only. Therefore, with this structure, a sufficient reinforcing effect cannot be obtained. In addition, in the central region of the flexible substrate 110, the reinforcing effect is reduced and the space efficiency is lowered.

  In the structure described in Patent Document 2, a relatively good reinforcing effect can be obtained. However, it is not easy to apply the adhesive 126 between the main board 100 and the flexible board 110 after soldering, and the process is complicated. Or, there is a concern about an increase in material costs.

  Note that the structure in which the main substrate and the flexible substrate are fixed using a rivet or the like requires a space for the rivet, and thus there is a problem in reducing the size of the flexible substrate.

  An object of the present invention is to provide a structure and method for connecting a flexible substrate to a main substrate with sufficient strength without introducing complicated operations.

  The connection structure of the present invention is for connecting a flexible substrate to a main substrate. A wiring pattern is formed on the main board. The flexible substrate has a plurality of connection terminals for connection to the wiring pattern of the main substrate, a plurality of wiring patterns respectively connected to the plurality of connection terminals, and a penetration formed between the plurality of wiring patterns. With holes. Then, a potting resin (for example, a room temperature curable silicone resin) is provided around the through hole and its periphery so as to reach the main substrate.

  In this structure, the flexible substrate and the main substrate are bonded at the positions where the respective through holes are provided. Therefore, the area where the bonding effect is obtained increases, and the bonding effect is improved as a whole. Further, the bonding between the main board and the flexible board can be reinforced only by potting the resin in a state where the flexible board is connected to the main board by the soldering operation.

  In the connection structure of another aspect of the present invention, the flexible substrate has a tip portion formed in a comb shape, and the tip of each protrusion of the comb shape portion is connected to the wiring pattern of the main substrate. A plurality of connection terminals are provided. Then, a potting resin is provided on the comb-shaped portion so as to reach the main substrate. According to this structure, the flexible substrate and the main substrate are bonded to each other by the concave portions of the comb.

  In the connection structure according to still another aspect of the present invention, the flexible substrate has a notch formed in a predetermined portion of the end thereof. And a potting resin is provided in the said notch part and its periphery so that it may reach the said main board | substrate. According to this structure, the flexible substrate and the main substrate are bonded using the notched portion.

  In the connection structure according to still another aspect of the present invention, a through hole is formed in the main substrate. The flexible substrate is connected to the main substrate in a state where a tip portion thereof passes through the through hole. And a potting resin is provided in the said through-hole and its periphery so that the said flexible substrate may be reached.

  In the connection structure of still another aspect of the present invention, a wiring pattern and a through hole are formed in the main substrate. The flexible substrate includes a plurality of connection terminals for connection with a wiring pattern included in the main substrate at a tip portion thereof. And a potting resin is provided in the said through-hole and its periphery so that the said flexible substrate may reach the said flexible substrate in the state connected to the said main substrate using the said some connection terminal.

  The connection method of the present invention includes a plurality of connection terminals for connection to a wiring pattern on the main substrate and a plurality of wiring patterns connected to the plurality of connection terminals, respectively, on the main substrate on which the wiring pattern is formed. A flexible substrate is connected. Then, a through hole is formed between the plurality of wiring patterns in the flexible substrate, the wiring pattern of the main substrate and the wiring pattern of the flexible substrate are soldered, and the through hole is reached so as to reach the main substrate. And potting resin is provided around it. According to this method, it is not necessary to apply an adhesive or the like between the main board and the flexible board after the soldering operation, and the bonding between them can be reinforced only by potting the resin.

  In the connection structure according to still another aspect of the present invention, the flexible substrate further includes an outer through hole in a region outside the plurality of wiring pattern groups. And a potting resin is provided in the periphery of the said through-hole, the said outer side through-hole, and these through-holes so that it may reach a main board | substrate.

In the connection structure according to still another aspect of the present invention, the outer through hole is formed larger than the through hole. In this structure, an adhesive effect is further obtained.
In the connection structure according to still another aspect of the present invention, the flexible substrate further includes a concave portion in a region outside the plurality of connection terminal groups at the tip portion. And a potting resin is provided in the periphery of the said comb-shaped part, the said recessed part part, and those parts so that it may reach a main board | substrate.

  In the connection structure according to still another aspect of the present invention, the concave portion is formed larger than the concave portion of the comb-shaped portion. Even in this structure, a further adhesive effect can be obtained.

  According to the present invention, a flexible substrate can be connected to a main substrate with sufficient strength without introducing complicated operations.

  FIG. 1 is a diagram illustrating an example of a connection structure according to an embodiment of the present invention. In FIG. 1, a main substrate 100 is, for example, an FR4 substrate, a glass epoxy substrate, an aluminum substrate, and the like, and includes a wiring pattern 101 for configuring an electric circuit using the surface and / or inner layer thereof. A flexible printed circuit (FPC) 1 is a sheet-like flexible substrate for connecting a signal line or a power line of the main substrate 100 to an external circuit, and is made of, for example, polyimide.

  A wiring pattern 2 for connecting the signal line or power line of the main board 100 to an external circuit is formed on the flexible board 1. In addition, a plurality of connection terminals (soldering lands) 3 for connecting the wiring pattern 101 included in the main substrate 100 and the wiring pattern 2 of the flexible substrate 1 are formed at the distal end portion of the flexible substrate 1. Here, a corresponding wiring pattern 2 is connected to each connection terminal 3. Although not particularly shown, soldering lands are also provided at corresponding positions on the main board 100, and the main board 100 and the soldering lands of the flexible board 1 are soldered together to form connection terminals. As a result, the corresponding wiring patterns 101 and 2 are connected to each other.

  The flexible substrate 1 includes a through hole 4 in the vicinity of a region where the connection terminal 3 is formed and between the wiring patterns 2. Although the diameter of the through-hole 4 depends on the thickness of the flexible substrate 1 and the viscosity of the potting resin 11 to be described later, it is formed to be, for example, 1 mm or more, preferably 1.5 mm or more.

  The potting resin 11 is potted on the surface side of the flexible substrate 1 connected to the upper surface of the main substrate 100. At this time, the potting resin 11 is potted at least on each through-hole 4 and its periphery, and is also potted on the end region of the flexible substrate 1 as necessary. Thereby, the potting resin 11 flows down so as to reach the main substrate 100 through the through holes 4. Further, in the end region of the flexible substrate 1, the potting resin 11 flows down and reaches the main substrate 100 as in the prior art shown in FIG. 5.

  When the above resin is cured, the potting resin 11 bonds the main substrate 100 and the flexible substrate 1. At this time, in the structure shown in FIG. 1, the flexible substrate 1 is bonded to the main substrate 100 by the potting resin 11 not only in the end region of the flexible substrate 1 but also in the region where each through hole 4 is formed. That is, according to this structure, the flexible substrate 1 is bonded to the main substrate 100 not only in the end region of the flexible substrate 1 but also in the central region. Therefore, according to this structure, a sufficient reinforcing effect can be obtained as compared with the structure described in Patent Document 1 that is joined only in the end region of the flexible substrate 1.

  In the connection structure of the embodiment, first, the through-hole 4 is formed in the flexible substrate 1 in advance, and then the wiring pattern 101 of the main substrate 100 and the wiring pattern 2 of the flexible substrate 1 are solder-connected. This is realized by providing the potting resin 11. Therefore, in the connection method of the embodiment, a laborious process of applying an adhesive while bending the flexible substrate after soldering is unnecessary, and workability is better than the method described in Patent Document 2. is there.

In addition, the shape of the through-hole 4 does not need to be circular, and may be another shape. However, considering the ease of pouring of the potting resin 11, a circular shape is preferable.
FIG. 2 shows an embodiment of the flexible substrate 1 according to the present invention. As shown in FIG. 2, the sizes of the through holes 4 may be different from each other. Further, the number of through holes 4 formed between the wiring patterns 2 need not be the same. In the example shown in FIG. 2, one or two through holes 4 are provided between the wiring patterns 2.

3 to 4 are modifications of the connection structure according to the present invention. Hereinafter, modified examples of the connection structure according to the present invention will be described with reference to these drawings.
In the configuration shown in FIG. 3, the tip of the flexible substrate 1 is formed in a comb shape, and the connection terminal 3 is provided at the tip of each protrusion of the comb-shaped portion. The potting resin 11 is provided so as to flow into the comb-shaped concave portion and reach the main substrate 100. According to this configuration, as in the configuration shown in FIG. 1, the main substrate 100 and the flexible substrate 1 are joined at a plurality of locations other than the end portions, so that the strength is increased.

  In the configuration shown in FIG. 4A, one or more notches are formed in a predetermined portion of the end portion of the flexible substrate 1. Here, the “predetermined portion of the end portion” refers to a side surface portion in a region near the tip of the flexible substrate 1 as shown in FIG. The potting resin 11 is provided so as to flow into the notch and reach the main substrate 100.

  In the configuration shown in FIG. 4B, the main substrate 100 includes a through hole 102 for allowing the flexible substrate 1 to pass therethrough. On the other hand, a connection terminal is provided at the tip of the flexible substrate 1, and the flexible substrate 1 is soldered to the main substrate 100 in a state of passing through the through hole 102. The potting resin 11 fixes the flexible substrate 1 to the main substrate 100 using the through holes 102.

  In the configuration shown in FIG. 4C, the main substrate 100 includes a through hole 103 for pouring the potting resin 11. On the other hand, a connection terminal is provided at the front end of the flexible substrate 1 and is soldered to the vicinity of the through hole 103 on the back surface of the main substrate 100. The potting resin 11 is flexible from the front surface side of the main substrate 1. It is poured into the through hole 103 so as to reach the substrate 1. The configuration shown in FIG. 4C is particularly useful for a configuration in which the back surface of the main substrate 100 is not brought into contact with a heat radiator or ground.

  In the configuration shown in FIG. 5A, the flexible substrate 1 shown in FIG. 1 is further provided with through holes 4-1 (outer through holes) in regions outside the plurality of wiring pattern 2 groups, and the through holes 4- 1 is made larger than other through holes 4-2 (through holes provided between the wiring patterns 2). And the potting resin 11 is potted at least around each through-hole 4-1, each through-hole 4-2, and each through-hole similarly to the said embodiment. Note that resin potting may also be performed on the end region of the flexible substrate 1 as necessary. When the potting resin 11 flows down and cures so as to reach the main substrate 100 through the through holes 4-1 and the through holes 4-2, the main substrate 100 and the flexible substrate 1 are joined.

  FIG. 5B is an example of the flexible substrate 1 shown in FIG. As shown in FIG.5 (b), the through-hole 4-1 is formed larger than the through-hole 4-2. Further, only the through hole 4-1 is not necessarily provided in the region outside the group of the wiring patterns 2. That is, as shown in FIG. 5B, the through hole 4-1 may be formed side by side with the wiring pattern 2 at the end portion of the flexible substrate 1.

  In the connection portion between the main substrate 100 and the flexible substrate 1, the place where the most external force or stress is applied is the end portions of the flexible substrate 1 (that is, the lands of the plurality of wiring patterns 101 of the main substrate 100 and the plurality of the flexible substrate 1 The connecting terminal 3 is a connecting portion at both ends of a plurality of connecting portions soldered to each other), and as shown in FIG. 5A, the through hole 4-1 is formed larger than the through hole 4-2. By doing so, the connection strength of the connection part of the main board | substrate 100 and the flexible substrate 1 can be raised.

Therefore, according to this structure, a reinforcing effect can be obtained more than the structure shown in Patent Document 1 and FIG. 1 that are joined only in the end region of the flexible substrate 1.
In this structure, first, the through-hole 4-1 and the through-hole 4-2 are formed in the flexible substrate 1 in advance, and then the land of the wiring pattern 101 of the main substrate 100 and the connection terminal 3 of the flexible substrate 1 are formed. And, finally, the potting resin 11 is provided, so that a time-consuming process of applying an adhesive while bending the flexible substrate after soldering is performed as in the above embodiment. It is unnecessary and has better workability than the method described in Patent Document 2.

  In addition, the structure shown to Fig.5 (a) can expand the mounting area of the flexible substrate 1 by making the through-hole 4-2 still smaller. Therefore, the configuration in which the through hole 4-1 is made larger and the through hole 4-2 is made smaller in this way ensures the strength of the connection portion between the main board 100 and the flexible board 1 and mounts the flexible board 1. Both reduction in density can be suppressed.

  In the configuration shown in FIG. 5A, the shape of the through hole 4-1 and the through hole 4-2 may be formed in a T shape or an L shape as shown in FIG. By configuring in this way, the perimeter of the hole can be made longer than in the configuration shown in FIG. 5A, so that the portion where the edge of the through hole and the potting resin 11 are in contact with each other is increased accordingly. The connection strength of the connection portion between the main substrate 100 and the flexible substrate 1 can be further increased.

  Further, in the configuration shown in FIG. 5A, the potting resin 11 is potted for each through-hole 4-1 or for each through-hole 4-2. However, as shown in FIG. It may be potted at once so as to straddle. With this configuration, the vertical movement of the apparatus for potting the resin is only one stroke, and the time required for attaching the flexible substrate 1 to the main substrate 100 can be shortened compared to FIG. .

  Further, in the configuration shown in FIG. 7, in the tip portion of the flexible substrate 1 shown in FIG. 3, a concave portion is provided in each of the regions outside the plurality of connection terminals 3 group (the portion surrounded by the broken line frame A shown in FIG. 7). And the concave portion is made larger than the concave portion of the other comb-shaped portion (the portion surrounded by the broken line frame B shown in FIG. 7). Then, resin potting is performed in the same manner as described above on the concave portions, the concave portions of other comb-shaped portions, and the periphery of those portions. In this way, by making the concave portion provided in the outer region of the group of the plurality of connection terminals 3 larger than the concave portion of the other comb-shaped portions, the main substrate 100 is similar to the configuration shown in FIG. The connection strength of the connection portion between the flexible substrate 1 and the flexible substrate 1 can be increased.

  Therefore, according to this structure, a reinforcing effect can be obtained more than the structure shown in Patent Document 1 and FIG. 3 that are joined only in the end region of the flexible substrate 1. Further, this structure does not require a time-consuming process of applying an adhesive while bending a flexible substrate after soldering, as in the above embodiment, and is easier to work than the method described in Patent Document 2. Is good.

It is a figure which shows an example of the connection structure of embodiment of this invention. It is an Example of the flexible substrate which concerns on this invention. It is the modification (the 1) of the connection structure concerning this invention. It is a modification (the 2-4) of the connection structure concerning this invention. It is the modification (the 5) of the connection structure concerning this invention. It is the modification (the 6) of the connection structure concerning this invention. It is the modification (the 7) of the connection structure concerning this invention. It is FIG. (1) which shows the conventional method of connecting a flexible substrate to a main substrate. It is FIG. (2) which shows the conventional method of connecting a flexible substrate to a main substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible substrate 2 Wiring pattern 3 Connection terminal 4 Through-hole 4-1 Through-hole 4-2 Through-hole 11 Potting resin 100 Main board 101 Wiring pattern 102, 103 Through-hole

Claims (10)

A main board on which a wiring pattern is formed;
Flexible including a plurality of connection terminals for connection to the wiring pattern of the main board, a plurality of wiring patterns connected to the plurality of connection terminals, and a through hole formed between the plurality of wiring patterns A substrate,
Potting resin provided in the through hole and its periphery so as to reach the main substrate,
Having a connection structure. A main board on which a wiring pattern is formed;
A flexible substrate having a tip portion formed in a comb shape, and having a plurality of connection terminals for connection to the wiring pattern of the main substrate at the tip of each protrusion of the comb shape portion;
Potting resin provided in the comb-shaped portion to reach the main substrate,
Having a connection structure. A main board;
A flexible substrate having a notch formed in a predetermined portion of the end, and
Potting resin provided in the notch and its periphery to reach the main substrate,
Having a connection structure. A main substrate having through holes formed therein;
A flexible substrate connected to the main substrate in a state where the tip passes through the through-hole,
Potting resin provided in the through hole and its periphery to reach the flexible substrate,
Having a connection structure. A main board on which wiring patterns and through holes are formed;
A flexible substrate including a plurality of connection terminals for connection with a wiring pattern included in the main substrate at the tip portion;
Potting resin provided in the through hole and its periphery so as to reach the flexible substrate in a state where the flexible substrate is connected to the main substrate using the plurality of connection terminals,
Having a connection structure. In a method of connecting a flexible substrate having a plurality of connection terminals for connection to the wiring pattern of the main substrate and a plurality of wiring patterns respectively connected to the plurality of connection terminals to the main substrate on which the wiring pattern is formed There,
In the flexible substrate, a through hole is formed between the plurality of wiring patterns,
Soldering the wiring pattern of the main board and the wiring pattern of the flexible board,
Providing a potting resin around the through hole and its periphery to reach the main substrate;
A connection method characterized by that. The flexible substrate further includes an outer through hole in an outer region of the plurality of wiring pattern groups,
The potting resin is provided around the through holes, the outer through holes, and the through holes so as to reach the main substrate.
The connection structure according to claim 1. The outer through hole has a shape larger than the through hole.
The connection structure according to claim 7. The flexible substrate further includes a concave portion in a region outside the plurality of connection terminal groups at the tip portion,
The potting resin is provided in the periphery of the comb-shaped portion, the concave portion, and those portions so as to reach the main substrate.
The connection structure according to claim 2. The concave portion has a shape larger than the concave portion of the comb-shaped portion.
The connection structure according to claim 9.