JPS629696A - Flexible printed wiring board and connection between printedwiring board and conductor pattern - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a flexible printed wiring board where a connection between conductor patterns is to be made, and an anisotropic conductive film interposed between the connecting portions of the conductor patterns on the printed wiring board. A flexible printed wiring board and a printed wiring board in which the connection between the conductor patterns on the flexible printed wiring board and the printed wiring board is made by pressurizing and heating the portion where the connection between the conductor patterns is to be made in a state where the conductor patterns are connected. This invention relates to a method for connecting a conductor pattern to a conductor pattern.

(Prior Art) An anisotropic conductive film is interposed between a flexible printed wiring board and a connecting portion of the conductive patterns on the printed wiring board where the connection between the conductive patterns is to be made.

A flexible printed wiring board and a printed wiring board in which the connection between the conductor patterns on the flexible printed wiring board and the printed wiring board is made by pressurizing and heating the portion where the connection between the conductive patterns is to be made. Methods for connecting conductor patterns are conventionally known.

Conventionally, when connecting conductor patterns between a flexible printed wiring board and a printed wiring board by the above-mentioned connection method, as illustrated in FIG. 3, conductor patterns cp, cp An anisotropic conductive film is interposed between the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board in the connection planned area A of the conductor pattern where the connection between the two is to be made, and A portion of the upper surface of the flexible printed circuit board FPC corresponding to the planned connection area A of the conductor pattern is heated to a predetermined temperature by heating the pressure and heating surface 2 of the pressure and heating member 1, that is, 1, for example, with a heating wire.
For example, while being heated to a temperature of about 200°C,
A pressurizing and heating member 1 having a size and shape corresponding to the entire connection area A of the conductor pattern described above.
The pressurized heating surface 2 of
/ci+" so that the conductor patterns of the flexible printed wiring board FPC and the printed wiring board PCB are electrically connected to each other by the anisotropic conductive film ACH. There is.

By the way, an anisotropic conductive film is interposed between the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board in the connection planned area A of the conductor pattern where the connection between the conductor patterns cp and cp is to be made. When pressing and heating the portion of the upper surface of the flexible printed wiring board FPC corresponding to the planned connection area A of the conductor pattern with the pressing and heating member l, the heating temperature and heating time are In Figure 6, the temperature change curve T1 and the electrical resistance change curve R1
If appropriate, conductor pattern cp as shown in
, cp is well established, but the heating temperature and heating time are unstable as shown by the temperature change curve T2 and the electrical resistance change curve R2 in FIG. If this is not done properly, even if they are once connected, the connection between the conductor patterns cp and cp will be separated when the pressurization and heating is stopped.

Therefore, when making a connection between the flexible printed wiring board and the conductor patterns on the printed wiring board, pressure heating at a predetermined temperature for 1 hour is required.

For example, a flexible printed wiring board FPC made of polyimide resin, a printed wiring board PCB made of glass, or a printed wiring board PCB made of epoxy resin mixed with glass fiber. As a matter of course, when being pressurized and heated by the above-mentioned pressurizing and heating member 1, it expands due to thermal expansion.

By the way, since the thermal expansion coefficient of the above-described flexible printed wiring board FPC is larger than that of the printed wiring board PCB, when pressurized and heated by the above-described pressurized and heated member 1,
The flexible printed wiring board FPC expands more than the printed wiring board PCB, and as a result, the flexible printed wiring board FP
Pattern misalignment may occur when connecting the conductor pattern between C and the printed wiring board PCB.

The size of the pattern deviation of the conductor pattern that occurs when connecting the conductor pattern described above is perpendicular to the direction of extension of the conductor pattern in the connection area A of the conductor pattern during connection of the flexible printed wiring board FPC. Length L in the direction of connecting (hereinafter referred to as the connection length of the connection planned area A of the conductor pattern).

Note that the length W in the extending direction of the conductor pattern in the connection area A of the conductor pattern described above (referred to as the width W of the connection area A of the conductor pattern) increases as the width W increases.

FIG. 4 shows an example of a pattern misalignment of the conductor pattern that occurs when the connection width of the planned connection area A of the conductor pattern is large. In a case where 256 conductor patterns CP are arranged at a pitch of 0.2 mm in a planned connection area A of a conductor pattern of a flexible printed wiring board FPC with a pitch of 51 mm, the conductor pattern has a pitch of 0.2 mm. 1mm
This appears when a pattern shift occurs.

If the above-mentioned pattern misalignment occurs, it is natural that the connection between the conductor patterns on the flexible printed wiring board FPC and the printed wiring board PCB will not be made satisfactorily, and this is possible. Features of a method for connecting conductor patterns between a flexible printed wiring board and a printed wiring board using an anisotropic conductive film that enables fine connections between the conductive patterns on the flexible printed wiring board and the printed wiring board It means that it is not made use of.

Therefore, in an attempt to solve the above problem, for example, a plurality of short flexible printed wiring boards connected in series are connected in the connection area A of the conductor pattern in the middle of the connection in the direction of the middle of the connection. Attempts have been made to connect the conductor patterns on the flexible printed wiring board FPC and the printed wiring board PCB by arranging the conductive patterns on the flexible printed wiring board FPC and the printed wiring board PCB. This is because the alignment work between the fine conductor patterns on the PCB and the connection work using the pressure heating member 1 must be performed a number of times corresponding to the number of flexible printed wiring boards used for connection. In addition to the drawback that it requires a lot of manufacturing time, the flexible printed wiring board used is constructed as a three-dimensional stack of individual boards to which the circuit components connected are attached. Therefore, there was a problem in that it was difficult to miniaturize a single device.

Therefore, as the flexible printed wiring board FPC itself, a single piece having predetermined connection holes as shown in FIG. 5(a) is used, and the flexible printed wiring board FPC and the printed wiring board PCB are
The connection work using the pressurizing and heating member 1 between the conductor patterns is first performed as shown in FIG. 5(c) for the connection planned area A having the connection center shown in FIG. 5(b). 5. Connect the conductive patterns using a pressure heating member only for part Aa of the planned connection area A. First, as shown in FIG. 5(d), press and heat the part Ab of the planned connection area A. Attempts have been made to connect conductive patterns using a member, but in this case, the end of the pressure heating member is attached to the flexible printed wiring board FPC at the portion where the end is pressure-welded, as shown in FIG. Wrinkles as shown in (a) occur, resulting in an unconnected part of the conductive pattern in that part, and the connection between the conductive patterns using a pressure heating member for part Ab of the connection planned area A. In this case, even if pressure heating is performed again using the pressure heating member in a state that includes the wrinkled portion, the end portion of the pressure heating member will not touch the flexible printed wiring board FPC in the pressed part. New wrinkles were generated, and it was found that this method could not provide a good connection between the conductor patterns of the flexible printed wiring board FPC and the printed wiring board PCB. Ta.

(Purpose) The purpose of the present invention is to pressurize and heat the connecting portions of the conductor patterns CP and CP between the flexible printed wiring board FPC and the printed wiring board PCB, and to connect the two using an anisotropic conductive film. It is an object of the present invention to provide a method for connecting a conductor pattern between a flexible printed wiring board and a printed wiring board, which does not cause the problems that have conventionally occurred.

(Structure) Hereinafter, specific details of the method for connecting conductor patterns between a flexible printed wiring board and a printed wiring board according to the present invention will be explained in detail with reference to the accompanying drawings.

11th! 1 and 25th! 1 is a diagram used to explain an embodiment of a method for connecting a conductor pattern between a flexible printed wiring board and a printed wiring board according to the present invention.

In each figure, A indicates a region to be connected, but in the method for connecting a conductor pattern between a flexible printed wiring board and a printed wiring board according to the present invention, the conductor is connected with an anisotropic conductive film interposed therebetween. For connecting portions of conductor patterns on flexible printed wiring boards and printed wiring boards where connections between patterns are to be made.

A planned connection area A of the conductor pattern is set, which consists of a first planned connection area A1 and a second planned connection area A2 arranged in order in the direction in which the conductor pattern extends, and In a state where the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board are in the correct connection correspondence relationship, the conductor pattern of the flexible printed wiring board and the conductor of the printed wiring board in the connection planned area of the above-mentioned conductor pattern. After interposing an anisotropic conductive film between the conductor pattern and the pattern, a part of the first connection area A1 and a part of the second connection area A2 of the conductor pattern are sequentially and alternately The vicinity of the end of a part of the first planned connection area and the vicinity of the end of a part of the second planned connection area are the first and second areas.
The flexible printed wiring board with the anisotropic conductive film interposed therebetween and the printed wiring board are heated under pressure in such a manner that they overlap each other in the extending direction of the planned connection area. It is designed to connect the conductive patterns of the flexible printed wiring board and the printed wiring board, and in the embodiment shown in the first figure, the connection area A of the conductive pattern is
One place in a part of the first planned connection area A1 and one place in a part of the second planned connection area A2 are sequentially and alternately arranged. The anisotropic conductive film is interposed in such a manner that the vicinity of the end of a portion of the planned connection area overlaps each other in the extending direction of the first and second planned connection areas. The flexible printed wiring board and the printed wiring board are heated under pressure to connect the conductor patterns between the flexible printed wiring board and the printed wiring board, and the second
In the illustrated embodiment, a portion 2 of the first connection area AI of the connection area A of the conductor pattern described above is used.
and one location of a part of the second planned connection area A2 are sequentially and alternately front-loaded, and the vicinity of the end of a part of the first planned connection area and the edge of a part of the second planned connection area are A flexible printed wiring board and printed wiring on which an anisotropic conductive film is interposed in such a manner that the areas near the first and second connection areas overlap with each other in the extending direction of the first and second connection areas. The conductor patterns on the flexible printed wiring board and the printed wiring board are connected by applying pressure and heating to the board.

First, in the embodiment shown in FIG. 1, the connection between the conductor patterns on the flexible printed wiring board and the printed wiring board in which the connection between the conductor patterns is to be made with an anisotropic conductive film interposed. A first connection planned area AI and a second connection area arranged in order in the direction in which the conductor pattern extends
Regarding the planned connection area A of the conductor pattern as shown in FIG.
In a state where the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board in the connection planned area A of the conductor pattern described above are in the correct connection correspondence relationship, the flexible conductor pattern in the connection planned area A described above is After interposing an anisotropic conductive film between the conductive pattern of the printed wiring board and the conductive pattern of the printed wiring board,
Part A11 of the first connection area A1 of the conductor pattern connection area A indicated by All in b) is heated under pressure at a predetermined temperature and time using a pressure heating member, and Connect the conductive patterns of the flexible printed wiring board and the printed wiring board corresponding to a portion All in the first connection planned area A1, and then Regarding a portion A21 in the second connection planned area A2 of the connection planned area A of the conductor pattern described above.

Pressure and heat with a pressure heating member at a predetermined temperature and time,
Part A21 in the second connection planned area A2 described above
The conductor patterns of the flexible printed wiring board and the printed wiring board corresponding to the printed wiring board are connected.

Then, a portion Al of the first connection planned area described above is
The vicinity of the end A11t of l and the vicinity of the end A21t of the part A21 of the second planned connection area overlap each other in the extending direction of the first and second planned connection areas AI and A2. , the above-mentioned portions All and A21 are set.

In addition, in the embodiment shown in the second figure, the connecting portion of the conductive patterns in the flexible printed wiring board and the printed Is board, where the connection between the conductive patterns is to be made with an anisotropic conductive film interposed therebetween. set. Regarding the planned connection area A of the conductor pattern as shown in FIG. In a state where the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board in the connection planned area A of the conductor pattern described above are in the correct connection correspondence relationship, the flexible conductor pattern in the connection planned area A described above is After an anisotropic conductive film is interposed between the conductor pattern of the printed wiring board and the conductor pattern of the printed wiring board, the connection plan of the conductor patterns described above is shown as All in FIG. 2(b). Part All in the first connection planned area A1 of area A
The conductor pattern of the flexible printed wiring board and the printed wiring board corresponding to the portion All in the first connection planned area A1 is heated under pressure with a pressure heating member at a predetermined temperature and for a predetermined time. and then connect (
Part A21 of the second connection area A2 of the conductor pattern connection area A shown in e) A21 is heated under pressure at a predetermined temperature and for a predetermined time using a pressure heating member. Connecting the conductive patterns of the flexible printed wiring board and the printed wiring board corresponding to a portion A21 in the second connection planned area A2, and furthermore, connecting the conductor patterns of the flexible printed wiring board and the printed wiring board, which is indicated by A12 in FIG. A portion A12 in the first connection area A1 of the conductor pattern connection area A is heated under pressure at a predetermined temperature and time using a pressure heating member to form a portion A12 in the first connection area A1. The conductor patterns of the flexible printed wiring board and the printed wiring board corresponding to A12 are connected.

Then, a portion Al of the first connection planned area described above is
The vicinity of the end A11t of l, the vicinity of the end A21t of the part A21 of the second planned connection area, and the vicinity A21t of the end of the part A21 of the second planned connection area, a and the first planned connection area Near the end of part A12 A1
2t refers to flSl and the second connection planned area AI, A2.
The above-mentioned portions All, A21. AI2 is set.

In each of the embodiments shown in FIGS. 1 and 2 described above, the flexible printed wiring board and the printed wiring board in which the connection between the conductive patterns is to be made with an anisotropic conductive film interposed therebetween are used. Schedule area A set at the connection part of
The first connection area A1 and the second connection area A2 which are lined up in order in the extending direction of the conductor pattern are smaller than each other in the extending direction of the first and second connection areas AI and A2. However, in carrying out the present invention, it is necessary to divide the conductor pattern into sections arranged in order in the extending direction of the conductor pattern in the planned area A set at the connecting portion of the conductor pattern. The first connection area A1 and the second connection area A2 are the same as the first connection area A1 and the second connection area A2. The connection between the conductor patterns as described above may be made while the second connection planned areas AI, A2 are divided into a large number of parts in the extending direction.

(Effects) As is clear from the detailed explanation above, in the method for connecting conductive patterns between flexible printed wiring boards and printed wiring boards of the present invention, flexible With an anisotropic conductive film interposed between the connecting parts of the conductive patterns between the printed wiring boards and the printed wiring boards, the parts where the conductive patterns are to be connected are heated under pressure to form flexible printed wiring. As a method for connecting conductor patterns between a flexible printed wiring board and a printed wiring board, in which the conductor patterns on the board and the printed wiring board are connected, an anisotropic conductive film is interposed between the conductor patterns. The connecting portion of the conductor pattern between the flexible printed wiring board and the printed wiring board, where the connection is to be made, consists of a first connection planned area and a second connection planned area arranged in order in the direction in which the conductor pattern extends. After setting the connection area of the conductor pattern and setting the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board in the connection area of the conductor pattern in the correct connection relationship, connect the conductor pattern as described above. After interposing an anisotropic conductive film between the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board in the connection area of the pattern, the first connection of the connection area of the conductor pattern is performed. A part of the planned connection area and a part of the second connection planned area are sequentially alternately arranged so that the vicinity of the end of the part of the first connection planned area and the vicinity of the end of the part of the second connection planned area are connected to the first connection area. and in such a manner that they overlap with each other in the extension direction of the second planned connection area.

A flexible printed wiring board with an anisotropic conductive film interposed therebetween and the printed wiring board are pressurized and heated to connect the conductive patterns of the flexible printed wiring board and the printed wiring board. In particular, in the method for connecting a conductor pattern between a flexible printed wiring board and a printed wiring board according to the present invention, the first . For each of the second connection planned regions, the connection portion where the connection between the conductor patterns is made is discontinuously divided into relatively short sections in the direction in which the connection planned region of the conductor pattern extends. 1st. A mode in which the second connection planned areas are sequentially alternated, and the vicinity of the end of each of the above-mentioned sequential connection parts overlaps with each other in the extending direction of the first and second connection planned areas. Therefore, even when connecting the conductor pattern between the large flexible printed wiring board and the printed wiring board, there is no pattern shift, and each separated connection part is Even if wrinkles occur at the ends of each separated connection portion when the connection operation is performed using the pressurizing and heating member, the area to be connected adjacent to the area to be connected where the wrinkles have occurred.

Since wrinkles are not generated at the positions corresponding to the wrinkles, no connection failure occurs in the entire connection area.1.The flexible printed wiring of the present invention In the method of connecting the conductor pattern between the board and the printed wiring board, the six problems of the conventional method described above can be satisfactorily solved.

[Brief explanation of the drawing]

1 and 2 are plan views of a connection area used to explain the method of connecting a conductor pattern between a flexible printed wiring board and a printed wiring board according to the present invention, and FIG. A perspective view of an example of a device for connecting conductor patterns between a wiring board and a printed wiring board, FIGS. 4 and 5 are plan views for explaining the manner of connection of conductor patterns in a connection planned area, and FIG. 6 is an explanatory diagram. FIG. A... Connection planned area, AI, A2... 1st. Second connection planned area, FPC...Flexible printed wiring board, PC
B...Printed wiring board, cp...Conductor pattern, 1.
... Pressure heating member, 2... Pressure heating surface,

Claims (1)

[Claims] A portion where the connection between the conductor patterns is to be made with an anisotropic conductive film interposed between the connection portion of the conductor pattern between the flexible printed wiring board and the printed wiring board where the connection between the conductor patterns is to be made. A method for connecting a conductive pattern between a flexible printed wiring board and a printed wiring board by applying pressure and heating to connect the conductive patterns on the flexible printed wiring board and the printed wiring board, the method being anisotropic. First connections arranged in order in the direction in which the conductor patterns extend are arranged at the connecting portions of the conductor patterns in the flexible printed wiring board and the printed wiring board, where the connection between the conductor patterns is to be made with a conductive film interposed therebetween. A planned connection area of the conductor pattern consisting of a planned area and a second planned connection area is set, and the conductor pattern of the flexible printed wiring board and the conductive pattern of the printed wiring board are connected within the planned connection area of the conductive pattern. After interposing an anisotropic conductive film between the conductor pattern of the flexible printed wiring board and the conductor pattern of the printed wiring board in the area where the conductor patterns are to be connected in the correct connection relationship, A part of the first connection area of the conductor pattern and a part of the second connection area of the conductor pattern are sequentially and alternately connected to the vicinity of the end of the part of the first connection area and the second connection area. A flexible film in which an anisotropic conductive film is interposed in such a manner that the vicinity of the end of a portion of the planned region overlaps with the first and second planned connection regions in the extending direction. The conductor pattern between the flexible printed wiring board and the printed wiring board is connected by pressurizing and heating the printed wiring board and the printed wiring board to connect the conductive patterns between the flexible printed wiring board and the printed wiring board. Connection method