JP2002134866A - Connection structure between printed circuit board and flexible wiring substrate, and connection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of a soldered part by increasing the strength of a bent part 18 of an electrode terminal 12 in a TCP(tape carrier package) 2, and also to facilitate interconnection between a printed circuit board and the TCP 2. SOLUTION: In the connection structure between a printed circuit board 1 and a TCP 2, lands 6 of the circuit board 1 and an electrode terminals 12 of the TCP 2 are connected to each other by bonding the lands 6 to the electrode terminals 12 exposed by a slit 11 of the TCP 2 by means of soldering. The length dimension of the lands 6 in a direction perpendicular to the array direction of the lands is made not to be smaller than the width dimension of the slit perpendicular to the array direction of the electrode terminals 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure and a connection device between a printed circuit board and a flexible wiring board, and more particularly, to the reliability of a soldered portion by increasing the strength of a bent portion of an electrode terminal of the flexible wiring board. The present invention relates to a connection structure and a connection device between a printed circuit board and a flexible wiring board, which facilitate the connection between the printed circuit board and the flexible wiring board, while improving the connection.

[0002]

2. Description of the Related Art Generally, in order to drive a liquid crystal display panel built in a liquid crystal display device, it is necessary to supply power to the liquid crystal display panel. Therefore, the lead terminals formed on the liquid crystal display panel and the TCP (T
An electrode terminal on the output side formed at one end of a flexible wiring board such as an ape carrier package is electrically connected. At the same time, the electrode terminals on the input side formed at the other end of the flexible wiring board are electrically connected to the lands formed on the printed circuit board. Thus, power is supplied from the printed circuit board to the liquid crystal display panel via the flexible wiring board, and the liquid crystal display panel is driven.

As a method of electrically connecting the electrode terminals formed on the flexible wiring board and the lands formed on the printed circuit board, a method of electrically connecting the electrode terminals of the flexible wiring board to the lands of the printed circuit board is known. After the alignment, a method of performing soldering, a method of establishing conduction through a connector, and a method of performing pressure bonding with an anisotropic conductive film (ACF), a conductive adhesive, or the like are considered. However, for reasons such as the structure of the module of the liquid crystal display device and connection using an ACF or the like is expensive and productivity is low,
Generally, a method of connecting the electrode terminals of the flexible wiring board and the lands of the printed circuit board by soldering has been adopted. The soldering method includes a method using a soldering iron, a method using pressure bonding with a heater bar, and a method using pulse heating or a light beam. Less than,
A conventional connection structure between a printed circuit board and a flexible wiring board when soldering with a soldering iron will be described with reference to FIGS.

As shown in FIG. 3, a plurality of electrodes 33 are formed of copper foil or the like on one surface of a substrate film 32 formed of a synthetic resin or the like constituting the flexible wiring board 31. The electrodes 33 at both ends of the flexible wiring board 31 are electrode terminals 36, and a plurality of electrode terminals 36 are arranged. The electrode terminal 36
Is removed, and a slit 35 for exposing the electrode terminal 36 at one end is removed.
Are formed. On the other side of the electrode 33 not in contact with the substrate film 32, a solder resist 34 is provided.
Is formed, and the solder resist 34 at a predetermined position is peeled off.

On the other hand, a plurality of electrodes 39 are formed on one surface of a base substrate 38 constituting the printed circuit board 37. Another surface of the electrode 39 that is not in contact with the base substrate 38 is coated with a solder resist 40, and the solder resist 40 at a position corresponding to the slit 35 is peeled off and extends to the electrode 39. The lands 41 are aligned and exposed. The land length dimension in the direction orthogonal to the land arrangement direction is formed to be shorter than the slit width dimension in the direction orthogonal to the electrode terminal 36 arrangement direction.

The flexible wiring board 31 is arranged above the printed circuit board 37 so that the electrode terminals 36 exposed by the slit 35 and the lands 41 face each other.

Next, a method of connecting the electrode terminals 36 of the flexible wiring board 31 and the lands 41 of the printed circuit board 37 will be described.

[0008] As shown in FIG.
After that, the soldering iron 45, which is a component of a soldering jig used for soldering, is lowered to the position where the land 41 and the slit 35 are arranged, and the electrode terminal 36 exposed by the slit 35 is moved. The land 41 and the electrode terminal 36 are bonded via the solder 44 by being sunk. As a result, the lands 41 of the printed circuit board 37 and the electrode terminals 36 of the flexible wiring board 31
Are electrically connected.

[0009]

However, the electrode terminals 36 exposed by the slits 35 with the soldering iron 45 are used.
When soldering while embedding, the land length dimension in the direction orthogonal to the land arrangement direction is formed to be shorter than the slit width dimension in the direction orthogonal to the arrangement direction of the electrode terminals 36, The land 41 exists outside the one bent portion 48a in the printed circuit board 37 side of the flat portion 47 of the electrode terminal 36 and in the recessed portion. Therefore, the solder 44 goes around the printed circuit board 37 side of the flat portion 47 and the outside of the one bent portion 48a of the electrode terminal 36 is covered with the solder 44 to form a fillet 49 of the solder 44. Thereby, the electrode terminal 36
The one bent portion 48a is reinforced to increase the strength.

On the other hand, since the land 41 does not exist outside the other bent portion 48b of the electrode terminal 36 in the recessed portion, the solder 44 does not flow around and the other bent portion 48b does not.
Since b is not covered with the solder 44, no fillet 49 of the solder 44 is formed. Therefore, the other bent portion 4
8b is not reinforced, and therefore has a problem that the electrode terminals 36 of the flexible wiring board 31 are disconnected.

[0011] Further, the demand for higher definition of the liquid crystal display device is increasing due to higher resolution of the liquid crystal display device and adoption of the liquid crystal display device for portable information terminal equipment. However, as the definition of the electrode terminals 36 of the flexible wiring board 31 and the lands 41 of the printed circuit board 37 increases, the widths of the electrode terminals 36 and the lands 41 become thinner, and the flexible wiring board When the electrode 31 was inserted, an extra force was applied to the electrode terminal 36. For this reason, if an impact is applied or the flexible wiring board 31 is bent, the electrode terminals 36 are cut and disconnected, so that the flexible wiring board 31 and the printed circuit Substrate 3
It is necessary to reinforce the connection part with 7 with a double-sided tape or the like. However, in this case, the connection process between the flexible wiring board 31 and the printed circuit board 37 is increased by one step, and there is a problem that it takes time and effort.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and aims to increase the strength of a bent portion of an electrode terminal of a flexible wiring board so as to improve the reliability of a soldered portion. An object of the present invention is to provide a connection structure and a connection device between a printed circuit board and a flexible wiring board for facilitating connection with the flexible wiring board.

[0013]

In order to achieve the above object, a connection structure between a printed circuit board and a flexible wiring board according to the first aspect of the present invention includes a plurality of lands arranged on a printed circuit board. A printed circuit that connects a land of the printed circuit board and an electrode terminal of the flexible wiring board by bonding a plurality of electrode terminals exposed and arranged in a line formed on the flexible wiring board by soldering. In the connection structure between the substrate and the flexible wiring board, the land length dimension in a direction perpendicular to the direction in which the lands are arranged is formed to be equal to or greater than a slit width dimension in a direction perpendicular to the direction in which the electrode terminals are arranged. It is characterized by.

According to the first aspect of the present invention, in order to bond the land to the electrode terminal exposed by the slit, the electrode terminal exposed by the slit is cut into the electrode terminal to bend. Even if it does,
There are lands outside both bent portions of the electrode terminal. For this reason, the solder for bonding the land and the electrode terminal exposed by the slit can cover the outside of both of the bent portions to form a fillet.

According to a second aspect of the present invention, there is provided a connection device between a printed circuit board and a flexible wiring board, wherein a width of a soldering iron used for the soldering is set to the width of an electrode terminal of the flexible wiring board. Are formed so as to have a dimension smaller than a slit width dimension in a direction orthogonal to the arrangement direction.

According to the second aspect of the present invention, the slit width in the direction orthogonal to the arrangement direction of the electrode terminals is formed longer than the width of the soldering iron. The tip can be lowered in parallel to one surface of the land, and the entire flat portion and both bent portions of the electrode terminal exposed by the slit can be in contact with the land via solder. Further, when the electrode terminal exposed by the slit is inserted into the soldering iron tip, no extra force is applied to the electrode terminal.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an embodiment of a connection structure between a printed circuit board and a flexible wiring board according to the present invention. In this embodiment, the connection structure is composed of a printed circuit board 1 and a TCP 2 which is a flexible wiring board. ing.

On one surface of the base substrate 3 constituting the printed circuit board 1, a plurality of electrodes 4 are formed by a copper foil or the like. The electrodes 4 at one end of the printed circuit board are connected to the lands 6 arranged in a line. Have been. The lands 6 are plated with gold or the like. A solder resist 5 is applied to the other surface of the electrode 4 which is not in contact with the base substrate 3, and the solder resist 5 at a position corresponding to the land 6 is peeled off to expose the land 6. ing.

On the other hand, on the other surface of the base substrate 3 where the electrodes 4 are not formed, conductive paths (not shown) for connecting components are printed.

On the other hand, the TCP 2 is constituted by a substrate film 9 formed of a flexible synthetic resin material such as polyimide or polyester. A plurality of electrodes 10 are formed on one surface of the substrate film 9 by copper foil or the like, and the electrodes 10 at both ends of the TCP 2 are an input-side electrode terminal 12 and an output-side electrode terminal (not shown), respectively. , A plurality of electrode terminals are arranged. The input side electrode terminal 12 and the output side electrode terminal are plated with tin or the like. The substrate film 9 at a position corresponding to the input-side electrode terminal 12 at one end of the TCP 2 is removed, and a slit 11 for exposing the electrode terminal 12 is formed.

Further, a solder resist 13 is applied to the other surface of the electrode 10 which is not in contact with the substrate film 9, and a solder resist 1 is provided at a predetermined position.
3 has been peeled off.

The TCP 2 is located above the printed circuit board 1 and is arranged such that the electrode terminals 12 exposed by the slits 11 and the lands 6 face each other.

The relationship between the land length in the direction perpendicular to the direction in which the lands 6 are arranged and the slit width in the direction perpendicular to the direction in which the electrode terminals 12 are arranged is such that the land length is greater than the slit width. It is formed so that it becomes. At this time, the land length dimension is set in consideration of an amount of misalignment of the TCP 2 when the TCP 2 is arranged above the printed circuit board 1. That is, the land length dimension is formed as the dimension obtained by adding the slit width dimension to the amount of misalignment of the TCP 2.

On the other hand, the printed circuit board 1 and the TC
A soldering jig is used for soldering for connection with P2. The soldering jig includes a mounting table (not shown) on which the printed circuit board 1 and the like are mounted, and a soldering iron 15 that can be moved up and down. The relationship between the width of the tip of the soldering iron 15 and the width of the slit in the direction orthogonal to the direction in which the electrode terminals 12 of the TCP 2 are arranged is as follows.
5 is formed so that the width dimension of the tip is smaller than the slit width dimension. At this time, the width dimension of the tip is set in consideration of the accuracy of the soldering jig.
In other words, the tip is formed to have a width shorter than the slit width obtained by subtracting the displacement due to the accuracy of the soldering jig.

Next, a method of connecting the printed circuit board 1 and the TCP 2 will be described.

As shown in FIG. 2, first, the printed circuit board 1 is mounted on the mounting table of the soldering jig such that the land 6 faces upward, and a flux (not shown) is applied to the land 6. ) And solder 17 are arranged.

Next, above the printed circuit board 1,
One end of the TCP 2 is arranged so that the land 6 and the input-side electrode terminal 12 exposed by the slit 11 face each other. Then, the soldering iron 15 heated to a predetermined temperature is lowered to a position where the land 6 and the slit 11 are arranged. In this case, the tip of the soldering iron 15 enters the inside of the slit 11, and the electrode terminal 12 pressed by the soldering iron 15 is fitted and bent. Both the bent portion 18 and the flat portion 19 of the electrode terminal 12 are in contact with the land 6 via the solder 17. At this time, the solder 17 wraps around between the land 6 and the flat portion 19 of the electrode terminal 12 on the printed circuit board 1 side, and covers the outside of the bent portion 18 to form a fillet 20.

Thereafter, the lands 6 of the printed circuit board 1 and the electrode terminals 12 of the TCP 2 are press-bonded via solder.
The soldering iron 15 is pulled up at a predetermined speed.

Thus, the lands 6 of the printed circuit board 1 are electrically connected to the electrode terminals 12 on the input side of the TCP 2.

The liquid crystal display panel can be driven by electrically connecting the electrode terminal on the output side of the TCP 2 and the lead terminal of the liquid crystal display panel.

Therefore, the land length of the printed circuit board 1 in the direction perpendicular to the direction in which the lands 6 are arranged in the present embodiment is longer than the slit width in the direction perpendicular to the direction in which the electrode terminals 12 of the TCP 2 are arranged. Even when the electrode terminal 12 is bent to bond the electrode terminal 12 exposed by the slit 11 to the land 6, the land 6 exists outside the bent portion 18. . For this reason, the solder 17 for bonding the land 6 and the electrode terminal 12 covers the outside of the two bent portions 18 to form the fillet 20, so that the bent portions 1 are formed.
8 is reinforced and the strength is increased. Therefore, TCP2
Is bent, the electrode terminal 12 of the TCP 2 does not break.

Further, both bent portions 1 of the electrode terminals 12 are formed.
Since the fillet 20 is formed on the outside of the base 8 and the strength is increased, it is not necessary to fix the TCP 2 and the printed circuit board 1 with a double-sided tape or the like so that the TCP 2 does not move after performing the conventional soldering. And therefore TC
The connection process between the P2 and the printed circuit board 1 can be simplified.

Further, since the width of the tip of the soldering iron 15 is shorter than the slit width in the direction orthogonal to the arrangement direction of the electrode terminals 12 of the TCP 2, the tip of the soldering iron 15 is The electrode terminal 12
The flat portion 19 and both bent portions 18 contact the land 6 in parallel via the solder 17. Therefore, the flat part 1
Since the fillet 20 is formed on the entire surface of the printed circuit board 1 on the side of the printed circuit board 9 and on the outside of both the bent portions 18, the strength can be increased. Further, when the electrode terminal 12 is pressed by the tip of the soldering iron 15, no extra force is applied to the electrode terminal 12, so that there is no disconnection.

In this embodiment, the connection between the printed circuit board 1 and the TCP 2 is made to drive the liquid crystal display panel, but the present invention is not limited to this.
Further, in the present embodiment, TCP2 is used as the flexible wiring board, but the present invention is not limited to this. For example, FPC (Flexible Print
d Circuit) or a flexible wiring board such as a heat seal may be used.

The present invention is not limited to the above-described embodiment, and can be variously modified as needed.

[0037]

Next, an embodiment of the present invention will be described.

First, in order to perform soldering, a printed circuit board and a TCP were prepared in which the pitch of the electrode terminals was 0.55 mm and the number of electrode terminals arranged was 45.

The printed circuit board has an electrode formed on one surface of the base board, a land formed by using an electrode at one end of the printed circuit board as an electrode terminal, and the land is subjected to gold plating. Further, a solder resist was applied to another surface of the electrode not in contact with the base substrate, and the land was exposed by peeling the solder resist at a position corresponding to the land. A land length dimension in a direction orthogonal to the land arrangement direction was 2.2 mm, and a land width dimension along the land arrangement direction was 0.35 mm.

On the other hand, in the TCP, an electrode made of 18 μm copper foil is adhered to one surface of a substrate film having a thickness of 75 μm with an adhesive, and electrodes at both ends of the TCP are respectively connected to an input terminal and an output terminal. As the electrode terminal, the electrode terminal was subjected to tin plating. The width of the electrode terminals along the arrangement direction of the electrode terminals was set to 0.25 mm. Further, a slit for exposing the electrode terminal was formed by peeling the substrate film at a position corresponding to the electrode terminal on the input side. The slit width in the direction orthogonal to the electrode terminal arrangement direction was 2 mm. Further, a solder resist was applied to another surface of the electrode not in contact with the substrate film, and the solder resist at a predetermined position was peeled off.

A soldering jig was used for soldering. The width dimension of the soldering iron tip of the soldering jig was 1.2 mm.

First, the printed circuit board was mounted on the mounting table of the soldering jig such that the lands face upward, and flux and solder were arranged on the lands. The solder used was KR-19RMA manufactured by Nippon Almit with a diameter of 0.5 mm.

Next, one end portion on which the input terminal of the TCP is formed is arranged above the printed circuit board so that the land and the electrode terminal exposed by the slit face each other. Then, by lowering the tip of the soldering iron heated to a temperature of 330 ° C. to the position where the land and the slit are arranged, and moving the soldering iron at a speed of 6 mm per second, TCP And the land of the printed circuit board were electrically connected.

Thus, the conventional printed circuit board and T
Since the land length dimension in the direction perpendicular to the land arrangement direction is longer than the slit width dimension in the direction perpendicular to the electrode terminal arrangement direction as compared with the connection structure with the CP, the electrode terminals exposed by the slits Even when the electrode terminal of the slit portion was sunk into the electrode portion to bond the land to the land, the land existed outside the both bent portions of the electrode terminal exposed by the slit. For this reason, the solder for connecting the electrode terminal of the TCP and the land of the printed circuit board covered the outside of the both bent portions and formed a fillet, so that the bent portions were reinforced. As a result, when the outside of one conventional bent portion is not covered with the solder and no fillet is formed, 180 ° of TCP
While the peel strength was 0.10 N / mm, in the present embodiment, the 180 ° peel strength of TCP was 0.15 N / mm.
N / mm or more, which was higher than the conventional value, and even if the TCP was bent, the electrode terminals of the TCP did not break.

In addition, since the strength has been increased as described above,
TC so that TCP does not move after conventional soldering
There is no need to fix and reinforce the P and the printed circuit board with a double-sided tape or the like, thus simplifying the process of connecting the TCP and the printed circuit board.

Further, since the slit width in the direction perpendicular to the arrangement direction of the electrode terminals of the TCP is longer than the width of the soldering tip, the tip is parallel to one surface of the land. The flat portion and both bent portions of the electrode terminal exposed by the slit can be lowered and come into parallel contact with the land via the solder. Therefore, since the fillet is formed on the entire surface of the flat portion on the side of the printed circuit board and outside the both bent portions, the strength can be increased.
Also, when the electrode terminal of the TCP is sunk into the tip of the soldering iron, no extra force is applied to the electrode terminal,
The electrode terminals did not break even when the TCP was bent.

[0047]

As described above, in the connection structure between the printed circuit board and the flexible wiring board according to the first aspect of the present invention, the length of the land in the direction orthogonal to the direction in which the lands are arranged is the length of the electrode terminal. Since the slits are formed longer than the slit width dimension in the direction perpendicular to the arrangement direction, the electrode terminals exposed by the slits are used to bond the lands and the electrode terminals exposed by the slits. Even in the case where bending is caused by being inserted, lands exist outside both bent portions of the electrode terminal. For this reason, the solder for bonding the land and the electrode terminal exposed by the slit can cover the outside of the bent portion to form a fillet.

Therefore, since the bent portion is reinforced and the strength is increased, even if the flexible wiring board is bent, the electrode terminals of the flexible wiring board do not break.

Further, since a fillet is formed outside the both bent portions to increase the strength, the flexible wiring board and the printed circuit board are fixed on both sides so that the flexible wiring board does not move after the conventional soldering. There is no need to reinforce by fixing with a tape or the like, and therefore, there is an effect that the connecting process between the flexible wiring board and the printed circuit board is simplified.

According to a second aspect of the present invention, there is provided a connection device for a printed circuit board and a flexible wiring board, wherein the slit width dimension in a direction orthogonal to the arrangement direction of the electrode terminals is the width of the soldering iron tip. Since the tip is formed longer than the dimensions, the tip can be lowered in parallel with one surface of the land, and the entire flat part and the bent part of the electrode terminal exposed by the slit are soldered. Can contact the land in parallel.

Therefore, the solder goes around the entire surface of the printed circuit board side of the flat portion, and a fillet is formed outside the bent portion on both sides of the electrode terminal that has been set in, so that the solder between the printed circuit board and the flexible wiring board can be formed. The strength of the connection can be further increased.

Further, when the flexible wiring board is pressed by the tip of the soldering iron, no extra force is applied to the electrode terminals, and the electrode terminals do not break even when the flexible wiring board is bent. It has the effect of.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a relationship between a printed circuit board and a flexible wiring board before connection in a connection structure between the printed circuit board and the flexible wiring board according to the present invention.

FIG. 2 is a schematic diagram showing the relationship between the printed circuit board and the flexible wiring board after connection in the connection structure between the printed circuit board and the flexible wiring board according to the present invention;

FIG. 3 is a schematic diagram showing a relationship between a printed circuit board and a flexible wiring board before connection in a conventional connection structure between a printed circuit board and a flexible wiring board.

FIG. 4 is a schematic diagram showing a relationship between a printed circuit board and a flexible wiring board after connection in a conventional connection structure between a printed circuit board and a flexible wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 TCP 3 Base substrate 4 Electrode 5 Solder resist 6 Land 9 Board film 10 Electrode 11 Slit 12 Electrode terminal 13 Solder resist 15 Soldering iron 17 Solder 18 Folding part 19 Flat part 20 Fillet

Claims (2)

[Claims] 1. A method according to claim 1, wherein the plurality of lands arranged on the printed circuit board and the plurality of electrode terminals exposed and arranged by slits formed on the flexible wiring board are bonded by soldering. In the connection structure between the printed circuit board and the flexible wiring board for connecting the land of the printed circuit board and the electrode terminal of the flexible wiring board, the land length dimension in a direction orthogonal to the arrangement direction of the lands is determined by the arrangement of the electrode terminals. A connection structure between a printed circuit board and a flexible wiring board, wherein the connection structure is formed so as to have a dimension not less than a slit width dimension in a direction orthogonal to the direction. 2. The method according to claim 1, wherein the plurality of lands arranged on the printed circuit board and the plurality of electrode terminals exposed and arranged by slits formed on the flexible wiring board are bonded by soldering. In a connection device for connecting a land of a printed circuit board and an electrode terminal of the flexible wiring board to the printed circuit board and the flexible wiring board, the width of a soldering iron used for the soldering is set to the width of the flexible wiring board. A printed circuit board and a flexible wiring board formed to have a dimension smaller than a slit width dimension in a direction orthogonal to the arrangement direction of the electrode terminals.