JP2014096260A - Flat wiring material and mounting body using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat wiring material and a mounting body using it which can be soldered and jointed with high reliability by reducing stress by temperature variation generated to solder materials connecting a connection unit and a mounted board when thermal compression bond formula is used to connect the flat wiring material to the mounted board.SOLUTION: A flat wiring material comprises multiple conductor for signals 2 arranged with intervals and arranged to a cross direction side by side, and multiple connection units 22 provided to at least one end of the multiple conductor for signals 2 and connected to a printed circuit board 7 through solder materials. The connection unit 22 comprises a convex part 221 that an area where the thickness of the solder materials is thin is a spot or a line along the cross direction between the printed circuit board 7, a flat part 222 that the thickness of the solder materials is thick between the mounted board, an under surface 222a facing to the printed circuit board 7, and a flat surface 222b on a contralateral surface of the under surface 222a.

Description

  The present invention relates to an MFJ (Multi Frame Joiner) including a flexible flat cable, a flat wiring material such as a flexible printed wiring board, and a mounting body using the same.

(Wiring components between printed wiring boards in in-vehicle devices)
Conventionally, wire harnesses are used for wiring components for electrical connection between a plurality of printed wiring boards mounted on an in-vehicle inverter unit, an engine control unit, or the like. In addition, a connection structure using connector parts is employed for electrical connection between the wire harness and the printed wiring board. In recent years, the use of wiring components in place of wire harnesses and the simplification of connection processes have been demanded as one measure for realizing the above-described in-vehicle devices that are smaller, lighter, and lower in cost.

  On the other hand, in-vehicle devices are also required to have high reliability that can withstand long-term use. It is indispensable to ensure reliability for a long-term vibration load and heat load for wiring components mounted on in-vehicle devices and their connection portions.

  In order to cope with the above-described reduction in size, weight and cost of in-vehicle devices, a plurality of conductors (mainly copper such as oxygen-free copper and tough pitch copper) arranged in parallel in the conductor width direction on the wiring components in the in-vehicle devices. Is used as a signal conductor, and a wiring component called a flexible flat cable (Flexible Flat Cable) that is integrated by adhesively coating an insulating film for coating from both sides in the conductor thickness direction is adopted. An inter-board connection structure has been devised.

  In this flexible flat cable, a conductor exposed portion where the conductor is exposed from the insulating film is formed at both ends in the conductor longitudinal direction, and at least a part of the conductor exposed portion is used as a conductor connecting portion for electrical connection with the printed wiring board. Is done. For flat wiring materials such as flexible flat cables used as wiring components in in-vehicle devices, MFJ (Multi Frame Joiner) with a structure similar to flexible flat cables and flexible printed circuit boards (Flexible Print Circuit: FPC) ) Etc. are also adopted. Although there are differences in the manufacturing method and constituent materials of the flat wiring material, these have a structure in which a plurality of conductors are arranged in parallel in the width direction to form a flat wiring material. Hereinafter, a flexible flat cable will be described as a representative example of a flat wiring material.

(Connector connection of connection part)
A pressure contact type connector may be used for electrical connection between a signal conductor of a flexible flat cable and a printed wiring board. The connection part of the terminal part of a flexible flat cable is inserted in the opening part of a connector, and the electrical continuity is taken by press-contacting the connection part of a flexible flat cable, and the electrode of a connector. In connection by a connector, the flexible flat cable is mechanically fixed by inserting the flexible flat cable into the opening of the connector.

  The connection of the flexible flat cable via the connector has an advantage that the flexible flat cable can be easily inserted and removed. However, in an in-vehicle device that is required to be reduced in size and weight, a space for installing a connector on a printed wiring board may not be designed.

  Also, in connection with a pressure contact type connector, a connection failure called a momentary disconnection in which the contact between the connection portion of the flexible flat cable and the electrode of the connector is temporarily interrupted by a vibration load may occur. There's a problem.

(Solder connection of connection part)
For electrical connection between the connection portion of the flexible flat cable and the electrode portion provided on the printed wiring board, a structure in which the connection is made directly with solder without using a connector may be employed. The direct connection by solder can cope with the miniaturization by reducing the area of the connection portion and can reduce the number of parts of the connection parts. Since the joining using the solder becomes a metal joining that forms an intermetallic compound, the electrical contact such as the pressure contact type connector does not occur instantaneously, and an electrically stable joining is obtained.

  Even in the structure where the connection part of the flexible flat cable and the electrode part of the printed wiring board are directly connected with solder, the load generated in the vicinity of the connection part is reduced by the vibration load like the conventional connector connection structure, and the resistance to vibration is improved. It is necessary to ensure reliability.

  However, the solder that connects the printed wiring board mounted on the device and the flat wiring material is repeatedly subjected to a thermal load due to a change in the temperature inside the vehicle and a change in the outside air temperature due to engine operation. In the connection between the flat wiring material and the printed wiring board, in such an environment where the temperature changes, stress is repeatedly generated in the solder due to the difference in expansion coefficient between the solder and the printed wiring board electrode. The electrical connection between the flat wiring material and the printed wiring board may be impaired.

  Also, when connecting a printed wiring board and a flat wiring material by a thermocompression bonding method such as pulse heat, the solder between the connection part and the electrode part may become thin because the solder is connected by thermocompression bonding. . When the solder is thinned, the stress acting on the solder increases when the temperature changes, and the temperature characteristics of the solder connection may be greatly impaired.

(Configuration to connect the connection part)
As a configuration for connecting the connecting portion to the electrode of the printed wiring board, conventionally, a deformed portion obtained by deforming a part of the connecting portion along the longitudinal direction is provided, and a solder pool is provided between the deformed portion and the electrode of the printed wiring board. Connected to the electrode of the printed wiring board by connecting a connecting portion having a groove wall to the surface in contact with the electrode on the printed wiring board via solder. The amount of solder that protrudes between lands by connecting a connecting portion having a cross-sectional shape of a trapezoid or inverted triangle whose base is smaller than the upper side (for example, cited document 2) to increase the bonding strength with the portion, via solder Has been disclosed (see, for example, cited document 3).

JP 2007-165476 A JP-A-5-206359 JP-A-5-217790

  However, in the configuration in which the groove portion along the longitudinal direction is provided in the connection portion described in Patent Document 1, a sufficient thickness of the solder material is secured in the center of the connection portion where the groove processing is formed. A region where the thickness of the surrounding solder material is small exists along the longitudinal direction of the connecting portion, and since the area of this region becomes large, when stress is generated due to temperature change, the solder material around the groove It is anticipated that excessive stress will be applied to the connection points.

  In the configuration in which the connecting portion described in Patent Document 2 does not have a flat portion, when soldering is performed by a thermocompression bonding method such as pulse heat, pressure and heating are performed from the upper surface of the connecting portion. It is conceivable that the contact area cannot be ensured, and the heat transmitted from the heating tool is insufficient, resulting in poor contact between the connecting portion and the mounted substrate due to unmelted solder material or the like.

  In the configuration in which the cross-sectional shape of the connection portion described in Patent Document 3 is a trapezoid, the area of the region where the thickness of the solder material formed on the bottom surface of the trapezoid of the connection portion is small increases, and this portion is excessively increased due to a temperature change. Is expected to generate a large amount of stress. Moreover, when a cross-sectional shape is a triangle, it is possible that a connection part twists in the width direction at the time of thermocompression bonding, and a connection part deform | transforms.

  Therefore, the object of the present invention is to reduce the stress due to the temperature change generated in the solder material connecting the connecting portion and the mounted substrate even when the thermocompression bonding method is used to connect the flat wiring material to the mounted substrate. Another object of the present invention is to provide a flat wiring material capable of highly reliable solder connection and a mounting body using the same.

In order to achieve the above object, one aspect of the present invention provides the following flat wiring material and connection structure thereof.
[1] A plurality of signal conductors arranged in parallel in the width direction at intervals,
A plurality of connection portions provided at at least one end of the plurality of signal conductors and connected to a substrate to be mounted via a solder material;
The connection portion is a first connection portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along the width direction, and
A second connecting portion having a region in which the thickness of the solder material between the mounting substrate is large;
A first flat surface provided on a surface opposite to the surface facing the mounting substrate;
Flat wiring material with
[2] The first connection portion is formed by a first protrusion protruding toward the mounted substrate,
The second connection portion is formed by a portion of the connection portion around the first convex portion,
The flat wiring material according to [1].
[3] The first convex portions respectively formed on the plurality of connection portions are formed at different positions in a longitudinal direction orthogonal to the width direction.
The flat wiring material according to [2].
[4] It further includes a fixing member that extends in the width direction at a position close to the connection portion and fixes the signal conductor.
The fixing member includes a fixing portion that is fixed to the mounting substrate by a solder material,
The fixing portion is a first fixing portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along a direction orthogonal to the width direction,
A second fixing portion having a region where the thickness of the solder material between the mounting substrate is large;
A second flat surface provided on a surface opposite to the surface facing the mounting substrate;
The flat wiring material according to [2] or [3].
[5] The first fixing portion is formed by a second protrusion protruding toward the mounted substrate.
The second fixing portion is formed by a portion of the fixing portion around the second convex portion,
The flat wiring material according to the above [4].
[6] The first and second convex portions are formed such that the vertex of the first convex portion of the connection portion and the vertex of the second convex portion of the fixed portion are located on substantially the same plane. The
The flat wiring material according to [4] or [5].
[7] The fixing member includes a positioning portion that is provided at an end portion of the fixing portion and is inserted into a through-hole provided in the mounted substrate to position the connection portion and the fixing portion.
The flat wiring material according to any one of [4] to [6].
[8] A plurality of signal conductors arranged at intervals in parallel in the width direction;
A plurality of connection portions provided at at least one end of the plurality of signal conductors and connected to a substrate to be mounted via a solder material;
The connection portion is a first connection portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along the width direction, and
A second connecting portion having a region in which the thickness of the solder material between the mounting substrate is large;
A flat wiring material with
A first flat surface provided on a surface opposite to the surface facing the mounting substrate;
A flat wiring material with
A mounting substrate including a signal electrode to which the connecting portion of the flat wiring material is connected via the solder material;
An implementation with
[9] The flat wiring member includes a fixing member that extends in the width direction at a position close to the connection portion, and fixes the signal conductor.
The fixing member includes a fixing portion that is fixed to the mounting substrate by a solder material,
The fixing portion is a first fixing portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along a direction orthogonal to the width direction,
A second fixing portion having a region where the thickness of the solder material between the mounting substrate is large;
A second flat surface provided on a surface opposite to the surface facing the mounting substrate;
The mounting substrate includes a fixing electrode to which a fixing portion is fixed.
The mounting body according to the above [8].
[10] The fixing member having a positioning portion that is provided at an end portion of the fixing portion and is inserted into a through-hole provided in the mounted substrate to position the connection portion and the fixing portion. With
The mounted substrate includes a through hole into which the positioning portion is inserted.
The mounting body according to [9].

  According to the present invention, even when the thermocompression bonding method is used to connect the flat wiring material to the mounted substrate, the stress due to the temperature change generated in the solder material connecting the connecting portion and the mounted substrate is reduced. Reliable solder connection is possible.

FIG. 1 is a plan view showing the appearance of the flexible flat cable according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a perspective view of the connecting portion of the flexible flat cable. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is a cross-sectional view showing a connection state between a flexible flat cable and a printed wiring board by a thermocompression bonding method, (a) showing a state before crimping, (b) showing a state during crimping, ( c) shows the state after pressure bonding. FIG. 6 is a plan view showing the appearance of a state in which the flexible flat cable is connected to the printed wiring board. 7 is a cross-sectional view taken along the line CC of FIG. FIGS. 8A and 8B are diagrams showing a second embodiment of the present invention, where FIG. 8A is a perspective view of a connecting portion, FIG. 8B is a view taken along arrow D in FIG. 8A, and FIG. The top view of a part, (d) is the E arrow directional view of (c), (e) is a front view of a convex member. FIG. 9 is a view showing a modified example of the present invention, and FIGS. 9A to 9D are perspective views showing a main part of the connection part of modified examples 1 to 4, respectively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, a flexible flat cable will be described as a representative example of a flat wiring material, but the present invention can be applied to other flat wiring materials such as MFJ and flexible printed wiring boards. In addition, in each figure, about the component which has the substantially same function, the same code | symbol is attached | subjected and the duplicate description is abbreviate | omitted.

[Summary of embodiment]
The flat wiring member according to the present embodiment is provided with a plurality of signal conductors arranged in parallel in the width direction at intervals, and at least one end of the plurality of signal conductors. In the flat wiring material having a plurality of connection portions connected to the electrodes for solder via the solder material, the connection portion has a dotted area in which the thickness of the solder material between the mounting substrate and the mounting substrate is small Or a second connection portion having a region in which the thickness of the solder material between the first connection portion that is linear along the width direction and the mounting substrate is large, and the mounting substrate. A first flat surface provided on the opposite surface and the opposite surface.

  “Mounted substrate” refers to a substrate to which one or both terminal portions of the flexible flat cable are electrically connected, and examples thereof include a printed wiring board. Examples of the printed wiring board include a flexible printed wiring board (FPC), a rigid printed wiring board, and a rigid flex printed wiring board that is a composite substrate of an FPC and a rigid printed wiring board. The “close position” is not limited to a position where the reinforcing member is slightly separated from the end where the conductor is exposed (for example, a distance shorter than the width of the reinforcing member), but may be a position where a part of the reinforcing member overlaps. The “solder material” includes paste solder (including cream solder), plate solder, and the like. The “vertex” of the convex portion includes one in which the vertex of the convex portion is linear. “Thickness is reduced” includes a state in which the apex of the convex portion and the printed wiring board are in contact with each other.

[First Embodiment]
FIG. 1 is a plan view showing the appearance of the flexible flat cable according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a perspective view of the connecting portion of the flexible flat cable. 4 is a cross-sectional view taken along line BB in FIG.

  As shown in FIG. 1, the flexible flat cable 1 has a plurality of signal conductors 2 arranged in parallel in the width direction at intervals, and a plurality of signal conductors 2 so that both end portions 20 of the signal conductors 2 are exposed. An insulating covering member 3 for covering, a pair of fixing members 4 for fixing the flexible flat cable 1 to the printed wiring board, and a pair of reinforcing members 5 for reinforcing the connection between the signal conductor 2 and the printed wiring board. Is provided.

(Signal conductor)
FIG. 5 is a diagram showing a connection state between a flexible flat cable and a printed wiring board by a thermocompression bonding method, (a) shows a state before thermocompression bonding, (b) shows a state during thermocompression bonding, c) shows the state after thermocompression bonding. FIG. 5 shows only the periphery of the signal conductor 2.

  As shown in FIG. 1, each signal conductor 2 is provided at at least one end 20 of the signal conductor 2, and is connected to the signal electrode 71 of the printed wiring board 7 shown in FIG. 5 via a solder material. The connecting portion 22 is provided. As shown in FIGS. 2 and 3, the connecting portion 22 protrudes toward the printed wiring board 7, and the thickness of the solder material between the apex 221 a of the convex portion 421 and the signal electrode 71 of the printed wiring board 7 is large. A lower surface that is formed by a semicircular convex portion 221 and a connecting portion 22 around the convex portion 221 so that the region to be small is linear along the width direction, and faces the printed wiring board 7. 222a includes a flat portion 222 connected to the solder material. The apex 221a of the convex portion 221 and the lower surface 222a of the flat portion 222 are electrically connected to the signal electrode 71 of the corresponding printed wiring board 7 via a solder material. The convex portion 221 is an example of a first connection portion, the flat portion 222 is an example of a second connection portion, and the flat surface 222b is an example of a first flat surface.

  The convex portion 221 is formed by deforming the connecting portion 22 so that the thickness of the solder material 82 between the flat portion 222 and the printed wiring board 7 becomes a predetermined thickness. The flat part 222 has a flat surface 222b provided on the surface opposite to the lower surface 222a. The flat portion 222 is provided so as to have a region where the thickness of the solder material 82 between the lower surface 222a and the signal electrode 71 of the printed wiring board 7 becomes large. The flat portion 222 is preferably provided so that the lower surface 222a thereof and the printed wiring board 7 are substantially parallel. With such a configuration, the thickness of the solder material 82 between the flat portion 222 and the printed wiring board 7 can be made uniform, so that a stronger connection can be obtained. The flat surface 222b is an example of a first flat surface.

  As shown in FIG. 3, the convex portions 221 are arranged at different positions of the connecting portion 22 in the longitudinal direction perpendicular to the width direction of the signal conductor 2, and there are a plurality of rows of convex portions 221 that can come into contact with the printed wiring board 7. Is formed. The convex portions 221 are provided at positions different from the convex portions 221 of the adjacent connecting portions 22, for example, and are arranged so that the convex portions 221 are alternately different in position as the whole connecting portions 22.

  As shown in FIGS. 2 and 5, the end portion 20 of the signal conductor 2 is bent portions 21 a and 21 b so that the apex 221 a of the convex portion 221 is positioned substantially on the same plane as the lower surface 5 a of the reinforcing member 5. Is bent to form an S shape (gull wing shape).

  For the signal conductor 2, copper or a copper alloy such as oxygen-free copper or tough pitch copper can be used. The surface of the copper or copper alloy may be plated, or a metal such as tin (Sn), nickel (Ni), or gold (Au) may be used alone or in a state where a plurality of materials are laminated.

(Coating member)
For the covering member 3, an insulating resin such as a film-like polyimide resin or polyethylene terephthalate (PET) resin can be used.

(Fixing member)
FIG. 6 is a plan view of a state in which the flexible flat cable is mounted on a printed wiring board. 7 is a cross-sectional view taken along the line CC of FIG.

  As shown in FIGS. 1, 2 and 4, the fixing member 4 is provided extending in the width direction at a position close to the connection portion 22 of the signal conductor 2, and as shown in FIGS. 6 and 7, A fixed portion 42 fixed to the fixing electrodes 72 of the pair of printed wiring boards 7 via solder material at both end portions 40 exposed from the reinforcing member 5 and a through hole 73 of the printed wiring board 7 inserted and connected. The positioning part 43 which positions the part 22 and the fixing member 4 is provided.

  The fixing part 42 protrudes toward the printed wiring board 7, and a region where the thickness of the solder material between the apex 421 a of the convex part 421 and the fixing electrode 72 of the printed wiring board 7 is small is orthogonal to the width direction. A convex part 421 formed in a semicircular shape so as to be linear along the direction, and a fixed part 42 around the convex part 421, and a lower surface 422 a facing the printed wiring board 7 is printed via a solder material A flat portion 422 fixed to the fixing electrode 72 of the wiring board 7 is provided. The apex 421a of the convex part 421 of the convex part 421 and the lower surface 422a of the flat part 422 are fixed to the corresponding fixing electrode 72 of the printed wiring board 7 via a solder material. The convex portion 421 is an example of a first fixing portion, and the flat portion 422 is an example of a second fixing portion.

  The flat portion 422 has a flat surface 422b provided on the surface opposite to the lower surface 422a. The flat portion 422 is provided so as to have a region where the thickness of the solder material between the lower surface 422a facing the printed wiring board 7 and the fixing electrode is large. The flat portion 422 is preferably provided such that the lower surface 422a thereof and the printed wiring board 7 are substantially parallel. With such a configuration, the thickness of the solder material 82 between the flat portion 422 and the printed wiring board 7 can be made uniform, so that a stronger connection can be obtained. The flat surface 422b is an example of a second flat surface.

  As shown in FIG. 4, the positioning portion 43 is provided at the end portion of the fixed portion 42, and is formed by being bent about 90 degrees by a bent portion 41c. The positioning part 43 is inserted into the corresponding through hole 73 of the printed wiring board 7. The positioning portion 43 can be positioned as long as it is inserted into the through hole 73, but is exposed from the back surface of the printed wiring board 7 so as to penetrate the through hole 73, and the end portion 431 is bent and fixed to the bent portion. It is good also as a structure which inserts the printed wiring board 7 by the part 42 and reinforces the connection part 22. FIG.

  As shown in FIGS. 4 and 7, the end portion 40 has a bent portion 41 a so that the vertex 421 a of the convex portion 421 is located on substantially the same plane as the vertex 221 a of the convex portion 221 and the lower surface 5 a of the reinforcing member 5. , 41b to form an S shape (gull wing shape).

  As shown in FIG. 1, the fixing member 4 has a wide portion 44 that is wider than the end portion 40. Since the fixing member 4 has the wide portion 44, the effect of fixing the vicinity of the connection portion 22 of the signal conductor 2 is enhanced.

  For the fixing member 4, it is preferable to use a material having higher strength (high tensile strength) than the signal conductor 2. For example, a copper alloy such as phosphor bronze or an iron (Fe) -nickel (Ni) alloy may be used. it can. The end 40 of the fixing member 4 may be plated with the same material as that of the end 20 of the signal conductor 2. Further, the thickness of the fixing member 4 is preferably thicker than the metal plate used for the signal conductor 2. By using a high-strength material and increasing the plate thickness, a higher reinforcing effect can be obtained in the vicinity of the connection portion 22 of the signal conductor 2 against the vibration load.

(Layer structure of flexible flat cable)
The layer configuration of the flexible flat cable 1 will be described with reference to FIG. The covering member 3 has a surface insulating film 30 bonded to the signal conductor 2 with an adhesive 31. For the adhesive 31 that adheres the signal conductor 2 and the insulating film 30, for example, a thermosetting resin such as an epoxy resin or an acrylic resin can be used.

  In the reinforcing member 5, the fixing member 4 is disposed on the one surface 3 a side of the covering member 3, the reinforcing metal plate 52 is disposed on the other surface 3 b side of the covering member 3, and the fixing member 4 or the reinforcing metal plate 52 is disposed. The insulating film 50, the fixing member 4, and the reinforcing metal plate 52 are fixed to the covering member 3 with an adhesive 51. The reinforcing member 5 acts as a reinforcing member that suppresses deformation in the vicinity of the connecting portion 22 of the signal conductor 2. The fixing member 4 and the reinforcing metal plate 52 may be fixed to the covering member 3 by welding (fusion) or ultrasonic welding by heating and cooling.

  The reinforcing metal plate 52 is preferably made of a material having a higher strength (high tensile strength) than the signal conductor 2, as in the case of the fixing member 4, such as phosphor bronze or iron (Fe) -nickel (Ni) alloy. Use. As long as the material satisfies the above conditions, the reinforcing metal plate 52 may use the same material as the fixing member 4 or a different material. The reinforcing metal plate 52 is preferably thicker than the metal plate used for the signal conductor 2. By using a high-strength material and increasing the plate thickness in combination with the fixing member 4, a higher reinforcing effect in the vicinity of the connection portion 22 of the signal conductor 2 against the vibration load can be obtained.

  The adhesive 51 that bonds the fixing member 4, the reinforcing metal plate 52, and the insulating film 50 to the covering member 3 for the signal conductor 2 is made of the same material as the adhesive 31 that bonds the insulating film 30 to the signal conductor 2. It may be used.

(Mounting method of flexible flat cable to printed wiring board)
Next, a method for mounting the flexible flat cable on the printed wiring board will be described.

  As shown in FIGS. 6 and 7, the printed wiring board 7 is formed on the insulating base 70 and the surface 70 a of the insulating base 70, and the signal electrode 71 to which the connection portion 22 of the signal conductor 2 is solder-connected. , And a fixing electrode 72 to which the fixing portion 42 of the fixing member 4 is soldered, a through hole 73 into which the positioning portion 43 of the fixing member 4 is inserted, and a signal electrode 71 on the surface 70a of the insulating base 70, fixing A solder resist 74 formed in a region other than the electrode 72 is provided, and as shown in FIG. 5A, the surface of the signal electrode 71 and the fixing electrode 72 has a paste solder material 81 containing a flux or a solvent. Prepare the one coated with. The solder material 81 is applied to the signal electrode 71 and the fixing electrode 72 by, for example, a method of supplying from a nozzle of a dispenser or a printing method. Alternatively, the printed wiring board 7 may be used in which the solder material 81 is applied to the signal electrode 71 and the fixing electrode 72 and then the solder material is formed by heating and solidifying the printed wiring board 7.

  First, as shown in FIGS. 6 and 7, the positioning portion 43 of the fixing member 4 is inserted into the through hole 73. Thereby, the connecting portion 22 is positioned on the corresponding signal electrode 71 of the printed wiring board 7, and at the same time, the fixing portion 42 of the fixing member 4 is positioned on the corresponding fixing electrode 72 of the printed wiring board 7. . As shown in FIG. 5A, the positioned connection portion 22 is disposed on the signal electrode 71 and the paste solder 81, and the fixing portion 72 and the paste solder material 81 are similarly applied to the fixing portion 42. Placed on top.

  Next, as shown in FIG. 5B, the thermocompression heating tool 100 is brought into contact with the flat surface 222b of the connecting portion 22 and the flat surface 422b of the fixing portion 42 so that the connecting portion 22 and the fixing portion 42 are viewed from above. Pressurize. The heating tool 100 has a pressing surface that can press and heat the connecting portion 22 and the fixing portion 42 in a lump, and is made of, for example, molybdenum, tungsten, or the like. In addition, the heating tool 100 is good also as a structure which pressurizes and heats the connection part 22 and the fixing | fixed part 42 separately.

  Next, an electric current is passed through the heating tool 100, and the connection portion 22 and the fixing portion 42 are instantaneously and locally heated by resistance heating of the heating tool 100. Thereby, the heating tool 100 melts the solder material 81. The melted solder material 81 is solidified by cooling, and the connecting portion 22 is connected to the signal electrode 71 and the fixing portion 42 is connected to and fixed to the fixing electrode 72 by the solder material 82 as shown in FIG.

(Effects of the first embodiment)
According to the present embodiment, the following effects can be obtained.
(A) By providing the semicircular convex portion 221 in the connecting portion 22 of the signal conductor 2 of the flexible flat cable 1, a region in which the thickness of the solder material connected to the printed wiring board 7 is reduced along the width direction. Since the influence of the stress generated in the solder material when the temperature changes is reduced, the connection reliability between the connection portion 22 and the printed wiring board 7 can be improved.

  That is, since the thickness of the solder material between the flat portion 222 and the signal electrode 71 of the printed wiring board 7 can be ensured by providing the projection 221, the temperature generated in the solder material. In other words, the influence of stress due to the difference in temperature expansion coefficient between the solder material and the printed wiring board 7 can be reduced. Thereby, the temperature characteristic of the solder connection can be improved, and cracking of the solder material and peeling from the signal electrode 71 can be suppressed.

(A) By providing the flat surface 222b of the connecting portion 22 and the flat surface 422b of the fixing portion 42, it is possible to secure the areas of the flat surfaces 222b and 422b that come into contact with the heating tool 100 during solder connection by the thermocompression bonding method. Thereby, the heat transmitted from the heating tool 100 is insufficient, so that contact failure between the connecting portion 22 and the fixing portion 42 and the mounted substrate 7 due to undissolved solder material or the like can be prevented.

(C) Since the convex portion 421 is provided in the fixing portion 42 of the fixing member 4 in the same manner as the connection portion 22, the solder material fixing the fixing portion 42 can also be suppressed because cracking of the solder material can be suppressed. The connection part 22 can be firmly fixed to the printed wiring board 7 by the member 4. Further, by providing the fixing portion 42 with the flat portion 422, it is possible to prevent poor contact between the fixing portion 42 and the mounted substrate 7 due to unmelted solder material or the like.

(D) The convex portion 221 of the connecting portion 22 is arranged at a position different from the adjacent connecting portion 22, and a plurality of rows of convex portions 221 that can come into contact with the printed wiring board 7 are formed. Since it can suppress that the connection part 22 inclines and deform | transforms sometimes, the stable solder connection can be performed by a thermocompression bonding system.

(E) By forming the apex 221a of the convex part 221 of the connection part 22 and the apex 421a of the convex part 421 of the fixed part 42 on substantially the same plane, when the heating tool 100 is thermocompression bonded, the convex parts 221 and 431 Since one of them can be prevented from floating and coming out of contact with the signal electrode 71 or the fixing electrode 72 of the corresponding printed wiring board 7, it is possible to suppress poor solder connection in the thermocompression bonding method.

(F) Since the positioning portion 44 is provided in the fixing member 4 and the positioning portion 44 is inserted into the through hole 73 provided in the printed wiring board 7, the connection portion 22 and the fixing portion 42 can be easily positioned. In addition, it is possible to suppress problems during connection between the flexible flat cable 1 and the printed wiring board 7 and to simplify the mounting and assembling work.

(G) Depending on the printed wiring board 7 on which the flexible flat cable 1 is mounted or the in-vehicle device unit housing structure on which the printed wiring board 7 is mounted, only the local heating method may be supported. The present embodiment can also be applied to such a case.

[Second Embodiment]
FIGS. 8A and 8B are diagrams showing a second embodiment of the present invention, where FIG. 8A is a perspective view of a connecting portion, FIG. 8B is a view taken along arrow D in FIG. 8A, and FIG. The top view of a part, (d) is the E arrow directional view of (c), (e) is a front view of a convex member.

  In the first embodiment, the convex portions 221 and 421 of the connecting portion 22 and the fixing portion 42 are provided by deforming the connecting portion 22 or the fixing portion 42. However, in the present embodiment, the convex portion 91 is provided. The convex member 9 is driven into the connecting portion 22 or the fixing portion 42 and provided. The following description will focus on differences from the first embodiment. In addition, the convex part 91 of the convex member 9 is an example of a 1st connection part and a 1st fixing | fixed part.

  The connection part 22 and the fixing part 42 are respectively provided with fixing holes 223 and 423 for fixing the convex member 9. The convex member 9 is provided at the end portion of the column portion 92 that is driven into the fixing holes 223 and 423 of the connecting portion 22 or the fixing portion 42 to fix the convex member 9, and the connecting portion 22 or the fixing portion 42. And a convex portion 91 projecting in a hemispherical shape on the printed wiring board 7 side. The convex portion 91 is provided so that a region where the thickness of the solder material is small is dotted, and is connected to the signal electrode 71 or the fixing electrode 72 of the printed wiring board 7 via the solder material. . In addition, you may form the convex part 91 in a triangular pyramid, a semi-cylinder, etc. Moreover, the convex member 9 may be fixed to the connection part 22 or the fixing part 42 by welding or adhesion.

(Effect of the second embodiment)
According to the present embodiment, the following effects can be obtained.
(A) Since the connecting portion 22 and the fixing portion 42 include the convex member 9 having the convex portion 91 protruding in a hemispherical shape, the thickness of the solder material between the printed wiring board 7 can be secured, The region where the thickness of the solder material is small can be narrowed by using the apex of the convex portion 91 as a dot. As a result, the influence of stress due to the difference in thermal expansion coefficient between the solder material and the printed wiring board 7 generated in the solder material when the temperature changes can be reduced, so that the connection portion 22 and the fixing portion 42 and the printed wiring board 7 can be reduced. Connection reliability can be further improved.
(A) Since the convex member 9 is driven into the fixing holes of the connecting portion 22 and the fixing portion 42 to form the convex portion 91, the flexible flat cable 1 including the convex portion 91 can be easily created.

[Modification]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. (A) thru | or (d) of FIG. 9 is a figure which shows the perspective view which shows the principal part of the connection part of the modification 1 thru | or 4 of this invention, respectively.

(Modification 1)
In the first embodiment, the connecting portion 22 has a configuration having one convex portion 221, 431. However, the connecting portion 22 and the fixing portion 42 have the connecting portion 22 as shown in FIG. It is good also as composition which has a plurality of convex parts 221 changed.

(Modification 2)
As shown in FIG. 9B, the connection portion 22 of Modification 2 is provided with a projection 224 obtained by deforming the connection portion 22 and a triangle.

(Modification 3)
As shown in FIG. 9C, the connection portion 22 of the third modification is provided with a plurality of convex members 9.

(Modification 4)
As shown in FIG. 9D, the connection part 22 of the modification 4 has a plurality of convex parts 225 regularly or irregularly on the surface of the connection part 22 facing the signal electrode 71 of the printed wiring board 7. It is good also as a structure to provide. The convex portion 225 may not be fixed to the connection portion 22.

  Further, the modified examples 1 to 4 may be applied to the fixing portion 42 as well as the connecting portion 22.

(Other variations)
In the embodiment of the present invention, the convex portions 221 of the connecting portions 22 are provided at different positions from the adjacent connecting portions 22, and the convex portions 221 are alternately arranged as a whole of the connecting portions 22. However, the connecting portion 22 may have a configuration in which the position of the convex portion 221 is different for each of the two connecting portions 22, or the convex portion 221 may be provided at an irregular position of the connecting portion 22.

  Moreover, it is also possible to remove some of the constituent elements of the above-described embodiment within a range not changing the gist of the present invention. For example, the reinforcing metal plate 52 can be omitted by increasing the rigidity of the reinforcing member. In addition, the mounting method described above may perform deletion, addition, change, replacement, etc. of steps within a range that does not change the gist of the present invention.

  The present invention is applicable to, for example, an in-vehicle device, a mobile phone, a communication device, an information terminal device, a measuring device, a home appliance, and the like.

DESCRIPTION OF SYMBOLS 1 ... Flexible flat cable, 2 ... Signal conductor, 3 ... Cover member, 3a, 3b ... surface,
DESCRIPTION OF SYMBOLS 4 ... Fixed member, 5 ... Reinforcement member, 5a ... Lower surface, 7 ... Printed wiring board, 9 ... Convex member, 20 ... End part, 21a, 21b ... Bending part, 22 ... Connection part, 30 ... Insulating film, 31 ... Adhesive, 40 ... end, 41a, 41b, 41c ... bent part, 42 ... fixing part, 43 ... positioning part, 44 ... wide part, 50 ... insulating film, 51 ... adhesive, 52 ... reinforcing metal plate, DESCRIPTION OF SYMBOLS 70 ... Insulating base material, 70a ... Surface, 71 ... Signal electrode, 72 ... Fixing electrode, 73 ... Through-hole, 74 ... Solder resist, 81, 82 ... Solder material, 91 ... Convex part, 92 ... Column part, 100 ... heating tool, 221 ... convex part, 221a ... vertex, 222 ... flat part, 222a ... lower surface, 222b ... flat surface, 223 ... fixing hole, 421 ... convex part, 421a ... vertex, 422 ... flat part, 422a ... lower surface, 422b ... flat surface, 431 ... end

Claims (10)

A plurality of signal conductors arranged in parallel in the width direction at intervals;
A plurality of connection portions provided at at least one end of the plurality of signal conductors and connected to a substrate to be mounted via a solder material;
The connection portion is a first connection portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along the width direction, and
A second connecting portion having a region in which the thickness of the solder material between the mounting substrate is large;
A first flat surface provided on a surface opposite to the surface facing the mounting substrate;
Flat wiring material with The first connection part is formed by a first convex part projecting to the mounted substrate side,
The second connection portion is formed by a portion of the connection portion around the first convex portion,
The flat wiring material according to claim 1. The first convex portions respectively formed on the plurality of connecting portions are formed at different positions in a longitudinal direction orthogonal to the width direction.
The flat wiring material according to claim 2. A fixing member that extends in the width direction at a position close to the connection portion and fixes the signal conductor;
The fixing member includes a fixing portion that is fixed to the mounting substrate by a solder material,
The fixing portion is a first fixing portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along a direction orthogonal to the width direction,
A second fixing portion having a region where the thickness of the solder material between the mounting substrate is large;
A second flat surface provided on a surface opposite to the surface facing the mounting substrate;
The flat wiring material according to any one of claims 1 to 3, further comprising: The first fixed portion is formed by a second convex portion protruding toward the mounted substrate side,
The second fixing portion is formed by a portion of the fixing portion around the second convex portion,
The flat wiring material according to claim 4. The first and second convex portions are formed such that the vertex of the first convex portion of the connection portion and the vertex of the second convex portion of the fixed portion are located on substantially the same plane,
The flat wiring material according to claim 5. The fixing member includes a positioning portion that is provided at an end of the fixing portion and is inserted into a through-hole provided in the mounted substrate to position the connection portion and the fixing portion.
The flat wiring material according to any one of claims 4 to 6. A plurality of signal conductors arranged in parallel in the width direction at intervals;
A plurality of connection portions provided at at least one end of the plurality of signal conductors and connected to a substrate to be mounted via a solder material;
The connection portion is a first connection portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along the width direction, and
A second connecting portion having a region in which the thickness of the solder material between the mounting substrate is large;
A flat wiring material with
A first flat surface provided on a surface opposite to the surface facing the mounting substrate;
A mounting substrate including a signal electrode to which the connecting portion of the flat wiring material is connected via the solder material;
An implementation with The flat wiring member is provided to extend in the width direction at a position close to the connection portion, and includes a fixing member that fixes the signal conductor.
The fixing member includes a fixing portion that is fixed to the mounting substrate by a solder material,
The fixing portion is a first fixing portion in which a region where the thickness of the solder material between the mounting substrate is small is a dot shape, or a linear shape along a direction orthogonal to the width direction,
A second fixing portion having a region where the thickness of the solder material between the mounting substrate is large;
A second flat surface provided on a surface opposite to the surface facing the mounting substrate;
The mounting substrate includes a fixing electrode to which a fixing portion is fixed.
The mounting body according to claim 8. The flat wiring member includes the fixing member provided at an end portion of the fixing portion and having a positioning portion that is inserted into a through-hole provided in the mounted substrate and positions the connection portion and the fixing portion.
The mounted substrate includes a through hole into which the positioning portion is inserted.
The mounting body according to claim 9.

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