JP4028160B2 - Terminal structure of flexible substrate and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a terminal structure for a flexible printed circuit board, and more particularly to a terminal structure for a flexible circuit board and a method for manufacturing the same, which can simultaneously bond a terminal reinforcing plate when connecting a connection terminal directly to the wiring of the flexible printed circuit board.
[0002]
[Prior art]
Conventionally, a connector as shown in FIG. 8 is known as a connector for a flexible printed circuit (FPC) mounted on an automobile or the like. This connector 100 is mainly used as a wiring connector for meters installed in a console panel of an automobile. The connector 100 has a structure in which, for example, an FPC 107 is inserted into a fitting hole formed in the meter housing 101 and the connector 110 is fitted to make electrical connection.
[0003]
That is, the FPC 107 forms a wiring pattern by printing a foil-like conductive material 105 on an insulating film 104 made of polyethylene terephthalate (PET), and further laminates a coverlay 106 thereon as a circuit protection member. However, the coverlay 106 is not formed at the end of the FPC 107 inserted into the fitting hole, and the conductive material 105 is exposed. On the other hand, a connection terminal 113 is connected to the tip of the circuit connection harness 112 accommodated in the terminal accommodation hole 111 inside the connector 110 by crimping or the like, and the connection terminal 113 is provided with an elastic contact piece 114. ing. That is, in this connector 100, by fitting the connector 110 into the fitting hole, the FPC 107 inserted earlier is sandwiched in the fitting hole, and the exposed conductive material 105 portion of the FPC 107 is elastically contacted with the connection terminal 113. Since the piece 114 contacts while pressing toward the wall surface of the fitting hole, it has a structure capable of ensuring electrical continuity.
[0004]
However, in the connector 100 described above, when all the circuit connection harnesses 112 accommodated in the terminal accommodation holes 111 inside the connector 110 are used in place of the FPC 107 in the state as they are, for example, all the connection terminals 113 are all FPCs. It is necessary to completely change the structure of the connector, such as changing the connector to the connector terminal and further changing the connector having the fitting hole on the meter housing 101 side to a new connector to connect to the connector 110. There is a risk that the cost of parts and the like will rise, leading to an increase in production cost.
[0005]
[Problems to be solved by the invention]
Therefore, in order to provide compatibility so that the harness 112 and the FPC 107 can be connected without incurring such an increase in cost, for example, as shown in FIG. The female connection terminal 80 is replaced with an FPC female connection terminal 60 having a similar fitting portion 62 and accommodated in a connector housing (not shown) as shown in FIG. Is fitted with another connector housing (not shown) in which the harness 112 and the FPC 107 are electrically connected.
[0006]
In this case, as shown in FIG. 8A, the female connection terminal 80 is joined to the tip of the wire 82 at the joining end 81 by, for example, crimping, as shown in FIG. A joining end 61 of the female connection terminal 60 is directly joined to a copper foil-like wiring 71 formed on the FPC 70. And a hot melt adhesive etc. are apply | coated / filled on it and a junction part is reinforced, and as shown in FIG. 10, the flat cable 86 provided with the connection terminal 60 for FPC is completed. In this case, since the joining end 61 of the female connection terminal 60 is used by directly joining the copper foil-like wiring 71 formed on the FPC 70, the joining between the joining end 61 and the wiring 71 is reliable and reliable. Must be expensive. Therefore, a joining method such as resistance welding is suitable for joining the joining end 61 and the FPC 70. In resistance welding, two metal surfaces are brought into contact with electrodes and further pressurized to flow a large current, and the contact portion of the metal surfaces is heated by Joule heat due to resistance to be melted and joined.
[0007]
As this resistance welding, of the spot welding methods as shown in FIG. 10, so-called series welding arranged in parallel toward the material to which the electrode 200 and the electrode 201 are joined can be considered. According to this series welding, the connecting terminal 60 to be joined is set on the FPC 107, the electrodes 200 and 201 are applied to the joining end portion 61 of the connecting terminal 60, and a large current is applied. Using heat generation, the plating is joined as a diffusing agent.
[0008]
Further, although the connection terminal 60 and the FPC 107 are joined, the FPC is usually disadvantageous in terms of peeling strength and the like as compared with other conductive materials such as electric wires, and therefore, as shown in FIG. The mold part 72 is formed by applying a material such as an agent or a curing agent to the joining portion (including a slight periphery) and applying a mold.
[0009]
As another connector for an FPC having such a molded portion, for example, as disclosed in Japanese Patent Laid-Open No. 6-310224 and Japanese Patent Laid-Open No. 7-106016, a plurality of conductors of a flat cable are welded or the like. 2. Description of the Related Art There is known a connector that has connected male connection terminals and is sealed and fixed in advance with a primary mold resin having electrical insulation so that these male connection terminals are electrically insulated from each other.
[0010]
However, even a connector that uses a molded FPC as described above, for example, as shown in FIG. 11, when the connection terminal 700 and the FPC 800 are pulled in opposite directions, or actually connected to the connector housing. When an FPC with a terminal joined is inserted, an external force such as a considerable peeling force is applied to the joint (connection part) 900 between the connection terminal and the FPC, and the joint 900 is peeled off or broken. There is a risk that. For this reason, for example, a reinforcing plate made of a synthetic resin or the like is attached to the lower surface of the joint portion 900 using, for example, a double-sided tape or an adhesive to give mechanical strength. However, this method is difficult to automate, and a joining member for attaching the reinforcing plate is required, leading to an increase in production cost. In addition, when the connection terminal is inserted into the connector housing at a predetermined interval, the connection terminal and the FPC must be joined at a precise interval when joining the connection terminal and the FPC. There is also a problem that it takes a long time for the joining work and causes an increase in production cost.
[0011]
The present invention has been made in view of such problems, and provides a terminal structure of a flexible substrate and a method of manufacturing the same that can simultaneously bond a terminal reinforcing plate when the flexible substrate and the connection terminal are bonded. The purpose is to do.
[0012]
[Means for Solving the Problems]
The terminal structure of the flexible substrate according to the present invention includes: a flexible substrate having a conductor pattern formed on an insulating film; and a metallic connection terminal having a joining end portion joined to the conductor pattern at an end portion of the flexible substrate. A reinforcing plate coupled to an insulating film on the opposite side of the conductive pattern at an end of the flexible substrate, and the reinforcing plate is integrally formed with a holding portion for holding the connection terminal at a tip side thereof. characterized in that it is become one.
[0013]
In the method for manufacturing a terminal of a flexible substrate according to the present invention, an end portion of a metal connection terminal is disposed on the conductor pattern of an end portion of the flexible substrate in which a conductor pattern is formed on an insulating film, and the flexible substrate In the state where the holding plate for holding the connection terminal is attached to the end of the substrate at the insulating film side, the reinforcing plate is integrally formed on the tip side, and the connection terminal is held by the holding portion of the reinforcing plate. In addition, resistance welding is performed between the end portion of the connection terminal and the conductor pattern of the flexible substrate, and at the same time, at least a part of the insulating film is melted by heat generated by the resistance welding, and the insulating film and the reinforcing plate It is characterized by welding.
[0015]
Further, it is preferable that a plurality of the connection terminals are arranged along the end portion of the flexible substrate, and a plurality of holding portions of the reinforcing plate are arranged in accordance with the arrangement pitch of the connection terminals.
[0016]
The connector further includes a connector housing that accommodates an end portion of the flexible substrate, a connection terminal, and a reinforcing plate, and the reinforcing plate has engaging protrusions projecting from both side end portions thereof, and the reinforcing plate is provided on a side wall of the connector housing. It is desirable that an engaging portion to be engaged with the engaging protrusion is formed.
[0017]
It is desirable that a heat-soluble adhesive is formed in advance on the surface of the reinforcing plate that contacts the insulating film.
[0019]
According to the present invention, a flexible board in which a conductor pattern is formed in a terminal structure of the flexible board, a connection terminal having a joining end joined to the conductor pattern, and a reinforcing plate coupled to the insulating film of the flexible board The reinforcing plate has a structure in which a holding portion for holding the connection terminal is integrally formed on the distal end side . For this reason, it is possible to realize a terminal having a mechanical strength higher than that of a normal flexible substrate. On the other hand, in the manufacturing method of the terminal of the flexible substrate, the end portion of the connection terminal is arranged on the conductor pattern of the flexible substrate, and the holding portion for holding the connection terminal is disposed on the distal end side on the insulating film side of the end portion of the flexible substrate. With the reinforcement plate formed integrally , the connection terminal is held by the holding portion of the reinforcement plate, and resistance welding is performed between the end portion of the connection terminal and the conductor pattern of the flexible substrate, and at the same time A method is adopted in which at least a part of the film is melted to weld the insulating film and the reinforcing plate. For this reason, a reinforcement board can be joined simultaneously at the process of joining a connecting terminal to a flexible substrate. Thereby, in the terminal manufacturing process of the flexible board, the process of joining the reinforcing plate after joining the connection terminal to the flexible board can be omitted, and it is possible to reduce the number of work processes and suppress the increase in production cost. Become.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a partial cross-sectional side view illustrating a joint portion at the time of simultaneous joining of a flexible substrate (FPC), a connection terminal, and a terminal reinforcing plate according to an embodiment of the present invention. A connection terminal (male or female connection terminal) 1 is connected to a terminal body 2 having a terminal fitting part (not shown) that fits with a fitting part (not shown) of a connection partner connection terminal, and the FPC 4. It is comprised from the junction edge part 3 which is. The FPC 4 has a wiring 6 made of a copper foil laminated conductive pattern formed on an insulating film 5 made of polyethylene terephthalate (PET) or the like, and a synthetic resin having electrical insulation on the insulating film 5 and the wiring 6. It has a structure covered with a cover lay 7 made of the like. Further, a terminal reinforcing plate 9 for reinforcing the joint portion 8 between the connection terminal 1 and the FPC 4 is disposed below the insulating film 5 of the FPC 4 so as to be in close contact with the insulating film 5. Note that the cover lay 7 of the FPC 4 is not formed in the portion that contacts the joint portion 8, and the wiring 6 that should originally be covered by the cover lay 7 is in an exposed state, and thus is in an exposed state. The joining end 3 of the connection terminal 1 can be brought into contact with the wiring 6, and the joining end 3 and the wiring 6 can be easily and directly connected by resistance welding.
[0021]
Simultaneous connection of the connection terminal 1, the FPC 4 and the terminal reinforcing plate 9 is realized by a method as described below. First, of the connection terminal 1, the FPC 4 and the terminal reinforcing plate 9 stacked as described above, the electrodes 10a and 10b are applied from the upper side of the joint end 3 of the connection terminal 1, and the electrodes 10a and 10b are used for resistance welding. Energize a large current of the capacity. Then, the contact end portion 3 and the contact surface 13a of the wiring 6 are welded by thermal energy (Joule heat) generated by energization. At this time, part of the insulating film 5 is also melted by the heat energy generated by energization, and the welded portion 12 is formed on the contact surface 13 b between the insulating film 5 and the terminal reinforcing plate 9. Finally, the energization of the electrodes 10a and 10b is stopped, the electrodes 10a and 10b are separated from the joint end 3 and the joint 8 is cooled, so that the formed weld 12 is solidified, and the connection terminal 1 and the FPC 4 And the terminal reinforcement board 9 is joined. If the joint portion 8 is formed in this way, the terminal reinforcing plate 9 can be joined at the same time in the joining step of the connection terminal 1 and the FPC 4, and therefore the step of joining the terminal reinforcing plate 9 to the joint portion 8 later. Can be omitted, and a flexible board having the same strength in the terminal portion can be produced more quickly. For this reason, it becomes possible to realize high efficiency of production work.
[0022]
In the simultaneous bonding method described above, as shown in FIG. 2, for example, a hot-melt adhesive (hot melt adhesive) 14 or the like is previously applied on the contact surface 13 b of the terminal reinforcing plate 9 with the insulating film 5. It may be applied. In this way, during the resistance welding, the adhesive force of the heat-dissolvable adhesive 14 is further added to the adhesive force of the welded portion 12 formed on the contact surface 13b between the insulating film 5 and the terminal reinforcing plate 9. Thus, the terminal reinforcing plate 9 can be bonded to the insulating film 5 to form the bonding portion 8. For this reason, the joint part 8 which has external force resistance, such as stronger peeling strength, can be formed, and the joining reliability in simultaneous joining can be improved.
[0023]
Further, as shown in FIG. 3A, a lance portion 15 is formed on the terminal reinforcing plate 9, and this lance portion 15 is engaged with a lance locking portion 16 below the terminal body portion 2 of the connection terminal 1. Then, the FPC 4 may be inserted between the connection terminal 1 and the terminal reinforcing plate 9 and then the simultaneous bonding may be performed. In this way, since it is possible to set in advance the exact position of the joint portion 8 composed of the connection terminal 1, the FPC 4 and the terminal reinforcing plate 9 to be formed by resistance welding, by performing simultaneous joining according to this setting, For example, it is possible to alleviate the difficulty of joining work, such as when a plurality of connection terminals 1 must be joined at a predetermined interval (pitch). In addition, according to the method of manufacturing a terminal of this example, the work consisting of three work processes, that is, a temporary fixing work and a joining work of the connection terminal 1 to the FPC 4 and a subsequent joining work of the terminal reinforcing plate 9 is performed as Since it can be performed in two work steps of “+ joining work”, the production work can be shortened. In such a simultaneous bonding method, as shown in FIG. 5B, the heat-soluble adhesive 14 is previously applied on the contact surface 13b of the terminal reinforcing plate 9 with the insulating film 5 in the same manner as described above. It is also possible to perform simultaneous bonding using the coated material and further increase the strength of the bonded portion 8.
[0024]
Next, the manufacturing process of the flat cable connector using the FPC 4 using the terminal reinforcing plate 9 having the lance portion 15, the terminal of the flexible substrate composed of the connection terminal 1 and the terminal reinforcing plate 9 will be described.
[0025]
As shown in FIGS. 4 and 5, first, the connection terminal 1 and the terminal reinforcing plate 9 are set at a position where the lance portion 15 and the lance locking portion 16 are engaged with each other. The FPC 4 is inserted so that the terminal portion without the cover lay 7 is in contact with the lower surface of the joint end 3 of the connection terminal 1 between the terminal reinforcing plate 9. Next, resistance welding as described above is performed to form the joint portion 8 composed of the connection terminal 1, the FPC 4 and the terminal reinforcement plate 9, and the FPC 4 with the terminal reinforcement plate 9 (hereinafter referred to as “flat”) to which the connection terminal 1 is joined. Cable terminal 20 "). A locking projection 17 is formed on the side surface of the terminal reinforcing plate 9, and the locking projection 17 is engaged with a locking hole formed in a connector housing described later to connect the flat cable terminal to the connector. It is locked and fixed in the housing.
[0026]
Next, as shown in FIG. 6, the flat cable connector 21 is completed by inserting the created flat cable terminal 20 into the accommodation hole 22 of the connector housing 18. Locking holes 19 are formed on both side surfaces of the connector housing 18 to engage with the locking protrusions 17 formed on both side surfaces of the terminal reinforcing plate 9 as described above, and the flat cable terminal 20 is connected to the connector housing. When inserted into 18, as shown in the AA ′ cross-sectional view of FIG. 7, the locking protrusion 17 and the locking hole 19 are engaged, and the flat cable terminal 20 is locked to the connector housing 18. As a result, the peel strength at the joint 8 of the flat cable terminal 20 is increased, and further, for example, the overall mechanical strength including the external force resistance against the external force from the connection terminal 1 side is greatly improved. To do. For this reason, by creating the flat cable connector 21 using the flat cable terminal 20 subjected to the above-described simultaneous bonding, it is possible to provide the flat cable connector 21 in which the bonding portion 8 is particularly difficult to break at low cost.
[0027]
【The invention's effect】
As described above, according to the present invention, a flexible substrate on which a conductor pattern is formed in a terminal structure of the flexible substrate, a connection terminal having a joining end portion joined to the conductor pattern, and an insulating film of the flexible substrate And a reinforcing plate that is integrally formed with a holding portion that holds the connection terminal on the tip side . For this reason, it is possible to realize a terminal having a mechanical strength higher than that of a normal flexible substrate. On the other hand, in the manufacturing method of the terminal of the flexible substrate, the end portion of the connection terminal is arranged on the conductor pattern of the flexible substrate, and the holding portion for holding the connection terminal is on the tip side on the insulating film side of the end portion of the flexible substrate. With the reinforcement plate formed integrally , the connection terminal is held by the holding portion of the reinforcement plate, and resistance welding is performed between the end portion of the connection terminal and the conductor pattern of the flexible substrate, and at the same time A method is adopted in which at least a part of the film is melted to weld the insulating film and the reinforcing plate. For this reason, a reinforcement board can be joined simultaneously at the process of joining a connecting terminal to a flexible substrate. Thereby, in the terminal manufacturing process of the flexible board, the process of joining the reinforcing plate after joining the connection terminal to the flexible board can be omitted, and it is possible to reduce the number of work processes and suppress the increase in production cost. The effect of becoming.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional side view showing a joint portion at the time of simultaneous joining of a flexible substrate, a connection terminal and a terminal reinforcing plate according to one embodiment of the present invention.
FIG. 2 is a partial side cross-sectional view showing a joint when a hot-melt adhesive is applied to the terminal reinforcing plate.
FIG. 3 is a partial cross-sectional side view showing a joint when a lance mechanism is formed on the terminal reinforcing plate.
FIG. 4 is a partial side cross-sectional view showing the simultaneous joining process of the FPC, the connection terminal, and the terminal reinforcing plate.
FIG. 5 is an upper perspective view showing the same process.
FIG. 6 is an upper perspective view showing a process of inserting the flat cable terminal created in the same process into the connector housing.
FIG. 7 is a cross-sectional view taken along the line AA ′ of FIG.
FIG. 8 is a cross-sectional view showing a conventional FPC connector.
FIG. 9 is a diagram illustrating a conventional terminal structure of a connection terminal and a connection structure between the connection terminal, a harness, and an FPC.
FIG. 10 is a partial side cross-sectional view for explaining the state of series welding in the resistance welding joining method.
FIG. 11 is an upper perspective view showing a state in which the joined connection terminal and the FPC are pulled in opposite directions.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Connection terminal, 2 ... Terminal main-body part, 3 ... Joint end part, 4 ... FPC, 5 ... Insulating film, 6 ... Wiring, 7 ... Cover-lay, 8 ... Joint part, 9 ... Terminal reinforcement board, 10 ... Electrode, DESCRIPTION OF SYMBOLS 12 ... Welding part, 13 ... Contact surface, 14 ... Hot melt adhesive, 15 ... Lance part, 16 ... Lance latching part, 17 ... Locking protrusion, 18 ... Connector housing, 19 ... Locking hole, 20 ... Flat Cable terminal, 21 ... flat cable connector, 22 ... receiving hole.

Claims (5)

A flexible substrate having a conductor pattern formed on an insulating film;
A metallic connection terminal having a joining end joined to the conductor pattern at an end of the flexible substrate;
A reinforcing plate coupled with an insulating film opposite to the conductor pattern at an end of the flexible substrate ;
The reinforcing plate is formed by integrally forming a holding portion for holding the connection terminal at a tip end side thereof . A plurality of the connection terminals are arranged along the end of the flexible substrate,
Holding portion of the reinforcing plate, the terminal structure of a flexible substrate according to claim 1, characterized in that a plurality of arranged in accordance with the arrangement pitch of the connection terminals. A connector housing that accommodates an end of the flexible substrate, a connection terminal, and a reinforcing plate;
The reinforcing plate has engaging projections projecting from both end portions thereof,
Wherein the side wall of the connector housing, the terminal structure of a flexible substrate according to claim 1 or 2, wherein the engaging portion engaging projections are engaged in the reinforcing plate is formed. On the conductor pattern of the end portion of the flexible substrate conductor pattern is formed on the insulating film, with placing the end of the metal connection terminal, the insulating film side of the end portion of the flexible substrate, the connection In the state where the holding portion for holding the terminal is integrally formed on the front end side, and the connecting terminal is held by the holding portion of the reinforcing plate, the end portion of the connecting terminal and the conductor of the flexible substrate At the same time, resistance welding is performed between the patterns, and at least a part of the insulating film is melted by heat generated by the resistance welding to weld the insulating film and the reinforcing plate. Production method. 5. The method for manufacturing a terminal of a flexible substrate according to claim 4 , wherein a heat-soluble adhesive is formed in advance on a surface of the reinforcing plate that contacts the insulating film.

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