JP2014157794A - Differential signal transmission cable, circuit board connection method and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize an electric characteristic with suppressed deformation of a differential signal transmission cable, and to increase the number of mounting of differential signal transmission cables per unit area in a circuit board.SOLUTION: A soldering part 32a for connecting an outer conductor 23 of a difference signal transmission cable 20 to a ground pad 32 of a circuit board is heated by a heat conduction sheet 40 from a remote position to thereby enable the soldering part to be fused. This enables the soldering part 32a to be fused without making an iron tip (heating tool) contact to an external conductor 23, without need of the conventional shield connection terminal, to connect the external conductor 23 to the ground pad 32. Thus, an electric characteristic of the differential signal transmission cable 20 can be stabilized while suppressing the deformation of an insulator 22. Further, with a reduced width size of the differential signal transmission cable 20, the number of mounting of the differential signal transmission cables 20 per unit area of the circuit board 30 can be increased.

Description

  The present invention relates to a circuit board connection method and a connection structure including a differential signal transmission cable for transmitting a differential signal whose phase is inverted by 180 degrees, and a pad to which a conductor of the differential signal transmission cable is connected. About.

  Conventionally, in devices such as servers, routers, and storage products that handle high-speed digital signals of several Gbit / s or more, differential interface standards such as LVDS (Low Voltage Differential Signal) have been adopted. Differential signals are transmitted between the circuit boards using a differential signal transmission cable. The differential signal has a feature of high resistance to external noise while realizing a low system power supply voltage.

  The differential signal transmission cable includes a pair of signal line conductors, and a positive signal and a negative signal whose phases are inverted by 180 degrees are transmitted to the signal line conductors. The potential difference between these two signals becomes the signal level. For example, if the potential difference is positive, the signal level is recognized as “High”, and if it is negative, the signal level is recognized as “Low”. Yes.

  As a technique that discloses a differential signal transmission cable for transmitting such a differential signal, for example, a technique described in Patent Document 1 is known. The technique described in Patent Document 1 includes a pair of signal line conductors arranged in parallel at predetermined intervals via an insulator. The periphery of the insulator is covered with a sheet-like outer conductor, and the periphery of the outer conductor is covered with a sheath as a protective outer skin.

  Then, by sequentially stripping one end side of the differential signal transmission cable, each signal line conductor and a part of the outer conductor are exposed to the outside. A metal shield connection terminal is connected to the exposed portion of the outer conductor by caulking. The shield connection terminal includes a plate-like metal and a solder connection pin integrally formed with the plate-like metal, and the plate-like metal is plastically deformed following the shape of the external conductor when caulking. Thus, the external conductor and the shield connection terminal are connected, and the external conductor is connected to the ground pad of the circuit board via the shield connection terminal.

JP 2012-099434 A (FIGS. 1 and 2)

  In the technique described in Patent Document 1 described above, the heat of the iron tip used in the solder connection operation [about 350 ° C.] touches the external conductor as compared with the case where the external conductor is directly solder-connected to the ground pad. Therefore, the insulator can be prevented from being deformed or melted by the heat of the tip.

  However, since the shield connection terminal is caulked along the shape of the outer conductor, the insulator inside the outer conductor is elastically deformed by the caulking force in some cases, and as a result, between the signal line conductors inside the insulator. Manufacturing problems such as changes in the distance may occur. As a result, there may be a problem that the electrical characteristics of the differential signal transmission cable vary from product to product.

  Furthermore, since the shield connection terminal is formed of a relatively thick plate-like metal, the width of the differential signal transmission cable to which the shield connection terminal is attached is increased. It has been difficult to increase the number of differential signal transmission cables mounted per area.

  An object of the present invention is to stabilize the electrical characteristics by suppressing the elastic deformation of the differential signal transmission cable, and to increase the number of differential signal transmission cables mounted per unit area of the circuit board. It is an object to provide a connection method and a connection structure between a differential signal transmission cable and a circuit board.

  In one aspect of the present invention, a cable preparation for preparing a differential signal transmission cable including a pair of signal line conductors, an insulator provided around the signal line conductor, and an external conductor provided around the insulator A step of preparing a circuit board having a grounding pad to which the outer conductor is connected, and a heat for contacting the soldering part provided on the grounding pad and heating the soldering part from a position apart A heat conduction member preparation step for preparing a conduction member, a heat conduction member setting step for bringing the heat conduction member into contact with the solder portion, a cable setting step for bringing the outer conductor into contact with the solder portion, and the heat conduction And a solder melting step for heating the member and melting the solder part.

  In another aspect of the present invention, after connecting the outer conductor and the ground pad, a heat conducting member removing step of removing the heat conducting member is performed.

  In another aspect of the present invention, a differential signal transmission cable having a pair of signal line conductors, an insulator provided around the signal line conductor, and an external conductor provided around the insulator, and the external conductor A circuit board having a ground pad to which the solder is connected and a solder part provided on the ground pad, a solder contact part in contact with the solder part, and a position away from the solder contact part, A heat conduction member having a heating jig contact portion that contacts the tool and applies heat to the solder contact portion.

  In another aspect of the present invention, the heat conducting member is provided with a plurality of the solder contact portions, and the heating jig contact portions are provided on both sides of the solder contact portions.

  In another aspect of the present invention, the solder contact portion is formed in a notch shape that opens a part of the periphery of the solder portion.

  In another aspect of the present invention, the solder contact portion is formed in a shape surrounding the entire circumference around the solder portion.

  In another aspect of the present invention, the solder contact portion is formed in a mesh shape that allows the molten solder portion to pass therethrough.

  In another aspect of the present invention, either one of the heat conducting member or the circuit board is provided with a fixed protrusion that protrudes toward the other of the heat conducting member or the circuit board, and the heat conducting member Alternatively, a fixed concave portion into which the fixed convex portion is inserted is provided on the other side of the circuit board.

  According to the present invention, the solder portion connecting the outer conductor of the differential signal transmission cable and the ground pad of the circuit board can be heated and melted from a position away from the heat conducting member. Thereby, the solder part can be melted and the external conductor and the ground pad can be connected without touching the external conductor without making the conventional shield connection terminal unnecessary.

  Therefore, elastic deformation and thermal deformation of the insulator can be suppressed, and the electrical characteristics of the differential signal transmission cable can be stabilized.

  Further, since the shield connection terminal can be omitted, the width of the differential signal transmission cable can be reduced, and the number of differential signal transmission cables mounted per unit area of the circuit board can be increased.

2 is a perspective view showing a connection structure between a differential signal transmission cable and a circuit board according to Embodiment 1. FIG. (A) is a perspective view of the cable for differential signal transmission, (b) is a sectional view of the cable for differential signal transmission. It is a disassembled perspective view which shows the state which decomposed | disassembled the connection structure of FIG. 1 for every part. It is a flowchart figure which shows the assembly procedure of the connection structure of FIG. It is a perspective view which shows the state which set the heat conductive sheet to the circuit board. It is a perspective view explaining the procedure which fuse | melts a solder part with a heating jig. 5 is a perspective view showing a heat conductive sheet according to Embodiment 2. FIG. 6 is a perspective view showing a heat conductive sheet according to Embodiment 3. FIG. It is a perspective view which shows the heat conductive sheet which concerns on Embodiment 4, and a circuit board. FIG. 12 is a flowchart showing an assembling procedure of a connection structure according to the fifth embodiment. FIG. 10 is a perspective view for explaining a solder application procedure according to the fifth embodiment. FIG. 10 is a flowchart showing a procedure for assembling a connection structure according to a sixth embodiment. It is a perspective view explaining the removal procedure of the heat conductive sheet which concerns on Embodiment 6. FIG.

  Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.

  1 is a perspective view showing a connection structure between a differential signal transmission cable and a circuit board according to the first embodiment, FIG. 2A is a perspective view of the differential signal transmission cable, and FIG. FIG. 3 shows a sectional view of the transmission cable, and FIG. 3 shows an exploded perspective view showing a state where the connection structure of FIG. 1 is disassembled for each part.

  As shown in FIG. 1, a differential signal transmission cable and circuit board connection structure 10 (hereinafter simply referred to as a connection structure) includes four differential signal transmission cables 20, one circuit board 30, 1 Two heat conductive sheets (heat conductive members) 40 are provided.

  As shown in FIG. 2, the differential signal transmission cable 20 includes a pair of signal line conductors 21. A positive signal as a differential signal is transmitted to one of the signal line conductors 21, and a negative signal as a differential signal is transmitted to the other of the signal line conductors 21. It is like that. Each signal line conductor 21 is formed by, for example, an annealed copper wire (Tinned Annealed Copper Wire) whose surface is tin-plated, and each signal line conductor 21 is covered with an insulator 22.

  Insulator 22 is formed of, for example, foamed polyethylene (Foamed Poly-Ethylene) in order to give flexibility to differential signal transmission cable 20, and its cross-sectional shape is formed in a substantially elliptical shape. The insulator 22 holds the signal line conductors 21 so as to be arranged at predetermined intervals, and the insulators 22 are provided around the signal line conductors 21 so as to have substantially the same thickness.

  However, the cross-sectional shape of the insulator 22 is not limited to a substantially elliptical shape as illustrated, and may be a substantially circular shape in which each signal line conductor 21 is individually covered, for example. Furthermore, the cross-sectional shape of the insulator 22 may be formed of a pair of parallel lines having the same length and a pair of semicircular shapes, for example, a shape substantially equal to a track in a track and field stadium.

  An outer conductor 23 for suppressing the influence of external noise is provided around the insulator 22. The outer conductor 23 is formed of, for example, a sheet-like copper foil and covers most of the insulator 22 except for an end portion along the longitudinal direction. However, the external conductor 23 is not limited to the copper foil, and may be another metal foil, or may be a braided sheet in which a thin metal wire such as an annealed copper wire is knitted.

  A sheath 24 is provided around the outer conductor 23 as a protective sheath for protecting the differential signal transmission cable 20, and the sheath 24 covers most of the outer conductor 23 except for the end portion along the longitudinal direction. It comes to cover. The sheath 24 is made of, for example, heat resistant PVC (Heat Resistant Polyvinyl Chloride).

  The signal line conductor exposed portion 20a for exposing each signal line conductor 21 to the outside by stripping the end portions of the differential signal transmission cable 20 along the longitudinal direction in sequence, and the external conductor 23 to the outside An exposed external conductor portion 20b is provided. That is, the signal line conductor exposed portion 20a and the outer conductor exposed portion 20b are provided in that order from the end of the differential signal transmission cable 20.

  As shown in FIG. 3, the circuit board 30 includes a board body 31 formed in an approximately rectangular plate shape by an insulating material such as an epoxy resin. The substrate body 31 includes a front side surface 31a, a pair of long side portions 31b, and a pair of short side portions 31c. The four differential signal transmission cables 20 are arranged side by side on the front side surface 31a of the substrate body 31 so as to extend along the extending direction of the long side portion 31b.

  The circuit board 30 is a circuit board dedicated for four to which four differential signal transmission cables 20 are connected. The front side surface 31a of the board body 31 has four grounds made of brass or the like having excellent conductivity. A pad 32 and eight signal line pads 33 are formed. Here, the circuit board 30 is a general-purpose printed board, and the pads 32 and 33 are printed on the front side surface 31a by performing an etching process or the like. However, the circuit board 30 is not limited to the printed board as described above, and a circuit board formed by inserting a steel plate functioning as a pad into the board body may be used. Furthermore, the circuit board is not limited to four, but may be a circuit board dedicated to two or a circuit board dedicated to eight.

  The respective ground pads 32 are arranged at substantially equal intervals in the extending direction of the long side portion 31 b of the substrate body 31. In addition, two signal line pads 33 are provided corresponding to one ground pad 32, and each signal line pad 33 extends from the side of the ground pad 32 to the short side portion 31 c of the substrate body 31. It is arranged to extend in the direction. One ground pad 32 and two signal line pads 33 correspond to one differential signal transmission cable 20, and each pad 32, 33 is an outer conductor of the differential signal transmission cable 20. 23 and the signal line conductors 21 are arranged with a predetermined interval in accordance with the arrangement relationship.

  Solder portions 32a and 33a (see shaded portions in the figure) are provided on the surface of each ground pad 32 and on the surface of each signal line pad 33 near the ground pad 32, respectively. Each solder part 32a, 33a is formed, for example, by applying a predetermined amount of paste-like solder material that can be cured at room temperature, and is provided in the final process for forming the circuit board 30 and the like. That is, the solder portions 32a and 33a are pre-applied to the circuit board 30, so that the step of applying solder can be omitted when the differential signal transmission cable 20 is connected.

  As shown in FIG. 3, the heat conductive sheet 40 is made of a metal plate made of brass or the like having excellent conductivity, and the thickness dimension is set to 0.2 mm to 0.3 mm. The heat conductive sheet 40 is formed in a substantially rectangular shape, and includes a pair of long side portions 40a and a pair of short side portions 40b. The size of the heat conductive sheet 40 is set to a size that can cover all of the four ground pads 32. The heat conductive sheet 40 has four solder contact portions 41 (two-dot chain lines in the figure). Is formed.

  Each solder contact portion 41 is arranged near one long side portion 40a (near side in the drawing) of the heat conductive sheet 40 and is in contact with each solder portion 32a provided on the surface of each ground pad 32. It has become. Each solder contact portion 41 is formed in a notch shape in which a part of the periphery of each solder portion 32a is opened under the state where the heat conductive sheet 40 is set on each solder portion 32a. That is, as shown in FIG. 3, the substantially U-shaped portion surrounded by the notched portion and the two-dot chain line of the heat conductive sheet 40 forms the solder contact portion 41.

  Here, when each differential signal transmission cable 20 is connected to the circuit board 30, the heat conductive sheet 40 is arranged so that the substantially U-shaped opening side of each solder contact portion 41 is directed to the signal line pad 33 side. Is set on each solder part 32a.

  Heat jig contact portions 42 (two-dot chain lines in the figure) are provided at both ends of the heat conductive sheet 40 along the longitudinal direction. Each heating jig contact portion 42 is provided so as to sandwich the four solder contact portions 41 from both sides along the longitudinal direction of the heat conductive sheet 40, and is provided at a position away from the solder contact portions 41. Specifically, each heating jig contact portion 42 is disposed at a position protruding outward from the short side portion 31 c of the circuit board 30. That is, each heating jig contact portion 42 is not disposed within the projection range along the vertical direction of the circuit board 30 and is disposed at a position that does not overlap with the circuit board 30 from the vertical direction.

  The heating jig HT1 (see FIG. 6) is brought into contact with each heating jig contact portion 42, whereby the heat of the heating jig HT1 is transferred to each heating jig contact portion 42 and each solder. It is transmitted to each solder part 32a via the contact part 41. Thus, each heating jig contact part 42 heats each solder contact part 41, and heats each solder part 32a indirectly. Here, since the heat conductive sheet 40 is made of copper made of brass or the like, the heat conductivity is good, and furthermore, the heating jig contact portions 42 at both ends along the longitudinal direction of the heat conductive sheet 40 are heated, respectively. The two solder contact portions 41 can be heated equally and efficiently to the same temperature with little variation.

  By providing each heating jig contact portion 42 in this way, damage (deformation of the insulator 22 and the like) due to pressing is not given to the differential signal transmission cable 20.

  Here, while the melting temperature of each solder part 32a is about 200 degreeC, the heating temperature of heating jig HT1 is about 300 degreeC. Therefore, as in the present embodiment, the device for melting the solder while separating the heating jig HT1 from the differential signal transmission cable 20 and the circuit board 30 as much as possible is an electrical characteristic of the connection structure 10. It is important to stabilize the process and improve the yield. However, you may provide the heating jig contact part 42 in any one along the longitudinal direction of the heat conductive sheet 40, without providing in the both ends along the longitudinal direction of the heat conductive sheet 40, respectively.

  Next, an assembly procedure of the connection structure 10 formed as described above, that is, a method for connecting the differential signal transmission cable 20 and the circuit board 30 will be described in detail with reference to the drawings.

  4 is a flowchart showing the assembly procedure of the connection structure of FIG. 1, FIG. 5 is a perspective view showing a state in which the heat conductive sheet is set on the circuit board, and FIG. 6 is a procedure for melting the solder part with a heating jig. The perspective view to explain is shown, respectively.

[Cable preparation process]
As shown in FIG. 4, first, in step S1, a differential signal transmission cable 20 (see FIG. 2) including a pair of signal line conductors 21, an insulator 22, an outer conductor 23, and a sheath 24 is prepared. Then, the end portions of the prepared differential signal transmission cable 20 are sequentially stripped as shown in FIG. 2, thereby forming the signal line conductor exposed portion 20a and the external conductor exposed portion 20b. This completes the operation in step S1 and completes the cable preparation process.

[Board preparation process]
Next, in step S2, the above-described circuit board 30 (see FIG. 3) including the solder portions 32a and 33a and capable of connecting the four differential signal transmission cables 20 is prepared. As a result, the operation in step S2 is completed, and the substrate preparation process (with the solder portion) is completed. Here, by preparing a circuit board (not shown) having a plurality of specifications according to the number of connections (two or eight) of the differential signal transmission cables 20, a connection structure having a plurality of specifications can be obtained. A corresponding production line can be formed.

[Heat conduction member preparation process]
In the subsequent step S3, the above-described heat conductive sheet 40 (see FIG. 3) provided with the four solder contact portions 41 and the two heating jig contact portions 42 is prepared. Thereby, the operation | work in step S3 is complete | finished and a heat conductive member preparation process is completed. Here, a plurality of specification heat conduction sheets (not shown) are prepared in accordance with the number of the differential signal transmission cables 20 to be connected (two or eight). Can be formed.

  In addition, since the above-mentioned step S1 thru | or step S3 each prepares each manufactured by another manufacturing process, you may replace in arbitrary orders. For example, the work may proceed in the order of step S1 from step S3 to step S2.

[Heat conduction member setting process]
In step S4, as shown by the arrow (1) in FIG. 3, the heat conductive sheet 40 is faced to the circuit board 30, and each solder contact portion 41 is set on each solder portion 32a. At this time, as shown in FIG. 5, the substantially U-shaped opening side of each solder contact portion 41 is directed to each signal line pad 33 side. Accordingly, each solder contact portion 41 is brought into contact with each solder portion 32a, and each heating jig contact portion 42 is disposed at a normal position that does not overlap with the circuit board 30 from the vertical direction. Thereby, the operation | work in step S4 is complete | finished and a heat conductive member setting process is completed.

[Cable setting process]
In the following step S5, first, the signal line conductor exposed portion 20a is stepped as shown in FIG. 1 so that the signal line conductor exposed portion 20a of each differential signal transmission cable 20 is disposed on the signal line pad 33. Form with a shape. Then, each differential signal transmission cable 20 is caused to face the circuit board 30 on which the heat conductive sheet 40 is placed, as shown by an arrow (2) in FIG. Then, the signal line conductor exposed portion 20a is placed on the signal line pad 33, and the external conductor exposed portion 20b is placed on the ground pad 32, respectively. Thereby, as shown in FIG. 6, each signal line conductor 21 is brought into contact with each solder portion 33a, and the outer conductor 23 is brought into contact with the solder portion 32a. Thereby, the work in step S5 is completed, and the cable setting process is completed.

[Solder melting process]
Next, in step S6, as shown by the arrow (3) in FIG. 6, the pair of rod-shaped heating jigs HT1 are heated to about 300 ° C. and contact the heating jig contact portion 42 of the heat conductive sheet 40. Let In the present embodiment, the heating jig contact portion 42 is sandwiched from above and below in order to improve the heating efficiency of the heat conductive sheet 40. However, the heating jig HT1 is not limited to a pair of rod-like shapes, and may be a clip shape capable of sandwiching the heat conductive sheet 40. Further, the heating jig HT1 is in contact with the upper side or the lower side of the heating jig contact portion 42. You may make it let it.

  Thereafter, the heat applied from each heating jig HT1 to each heating jig contact portion 42 is efficiently transmitted to each solder contact portion 41 (see FIG. 5) in a short time, and each solder contact portion 41 is substantially evenly distributed. Heated. Thereby, each solder part 32a contacted to each solder contact part 41 is heated, and as a result, each solder part 32a is melted. Next, the heating jig HT <b> 1 is separated from the heating jig contact portion 42, and heating to the heat conductive sheet 40 is stopped. As a result, the external conductor 23 is connected to the ground pad 32 via the solder portion 32a.

  Thereafter, as indicated by an arrow (4) in FIG. 6, the tip of the heating jig HT2 formed in a bar shape is caused to face each signal line conductor 21, and each solder portion 33a is melted. Thereby, each signal line conductor 21 is connected to each signal line pad 33 via each solder part 33a. Here, the connection of each signal line conductor 21 to each signal line pad 33 is not limited to the above-described solder connection, and may be connected using an ultrasonic welding machine or the like.

  Thereby, the operation in step S6 is completed, and the solder melting process is completed.

  As described above in detail, according to the connection structure 10 according to the first embodiment, the solder portion 32a that connects the outer conductor 23 of the differential signal transmission cable 20 and the ground pad 32 of the circuit board 30 is heated. The conductive sheet 40 can be heated and melted from a remote position. As a result, the solder portion 32a is melted without touching the outer conductor 23 with the tip (heating jig HT1) while eliminating the need for the conventional shield connection terminal, so that the outer conductor 23 and the ground pad 32 are connected. Can be connected.

  Therefore, elastic deformation and thermal deformation of the insulator 22 can be suppressed, and the electrical characteristics of the differential signal transmission cable 20 can be stabilized.

  Further, since the shield connection terminal can be omitted, the width of the differential signal transmission cable 20 can be reduced, and the number of differential signal transmission cables 20 mounted per unit area of the circuit board 30 can be increased. It becomes.

  Next, Embodiment 2 of the present invention will be described in detail with reference to the drawings. Note that portions having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 7 is a perspective view showing a heat conductive sheet according to the second embodiment.

  As shown in FIG. 7, the heat conductive sheet 40 according to the second embodiment is different from the first embodiment only in the shape of each solder contact portion 50. Each solder contact portion 50 is formed in a shape that covers the entire circumference of each solder portion 32a under the state where the heat conductive sheet 40 is set on each solder portion 32a. Specifically, each solder contact portion 50 is formed in a substantially rectangular frame shape surrounded by a hollowed portion of the heat conductive sheet 40 and a two-dot chain line.

  Also in the second embodiment formed as described above, the same operational effects as those of the first embodiment described above can be achieved. In addition, in the second embodiment, since each solder contact portion 50 is formed in a frame shape instead of a notch shape, the rigidity of the entire heat conductive sheet 40 can be increased. Therefore, the heat conductive sheet 40 can be set on the circuit board 30 more easily.

  Next, Embodiment 3 of the present invention will be described in detail with reference to the drawings. Note that portions having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 8 is a perspective view showing a heat conductive sheet according to the third embodiment.

  As shown in FIG. 8, the heat conductive sheet 40 according to the third embodiment is different from the first embodiment only in the structure of the portion where each solder contact portion 60 is formed. Specifically, the other portions of the heat conductive sheet 40 except for each heating jig contact portion 42 are formed in a mesh shape (mesh shape) by braiding a thin copper wire. That is, the melted solder portion 32a passes through the portion where each solder contact portion 60 is formed.

  Also in the third embodiment formed as described above, the same operational effects as in the first embodiment described above can be achieved. In addition, in the third embodiment, since it is not necessary to form a relatively large cutout or cutout as in the first and second embodiments, the rigidity of the entire heat conductive sheet 40 can be further increased. it can. Therefore, the heat conductive sheet 40 can be set on the circuit board 30 more easily.

  Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings. Note that portions having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 9 is a perspective view showing a heat conductive sheet and a circuit board according to the fourth embodiment.

  As shown in FIG. 9, the heat conductive sheet 40 according to the fourth embodiment is provided with a pair of fixing pins (fixed convex portions) 70 on the opening side of each solder contact portion 41 as compared with the first embodiment. It has been. Each fixing pin 70 protrudes toward the circuit board 30. On the other hand, each ground pad 32 and each solder portion 32 a of the circuit board 30 are provided with a pair of fixing holes (fixed recesses) 71 so as to face the respective fixing pins 70. That is, each fixing pin 70 is inserted into each fixing hole 71 in a state where the heat conductive sheet 40 is set on each solder portion 32a.

  However, the fixing pins 70 and the fixing holes 71 may be provided in reverse. That is, each fixing pin 70 may be provided in each ground pad 32 and each solder portion 32 a of the circuit board 30, and each fixing hole 71 may be provided in each solder contact portion 41 of the heat conductive sheet 40.

  In the fourth embodiment formed as described above, the same operational effects as those of the first embodiment can be obtained. In addition, in Embodiment 4, the positioning accuracy of the heat conductive sheet 40 with respect to the circuit board 30 can be improved. Therefore, the yield of the connection structure 10 can be further improved. Moreover, each solder contact part 41 and each solder part 32a can be made to contact more reliably, and by extension, the heat of heating jig HT1 (refer FIG. 6) can be more reliably transmitted to each solder part 32a. Can do.

  Next, a fifth embodiment of the present invention will be described in detail with reference to the drawings. Note that portions having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 10 is a flowchart showing the assembly procedure of the connection structure according to the fifth embodiment, and FIG. 11 is a perspective view for explaining the solder application procedure according to the fifth embodiment.

  As shown in FIG. 10, the assembly procedure of the connection structure 10 in the fifth embodiment is performed in steps S10 and S11 in place of steps S2 and S4 (see FIG. 4) in the first embodiment, and steps S5 and S4 are performed. The difference is that the operation of S6 is performed in the reverse order.

  In step S10, as shown in FIG. 11, a circuit board 80 that does not include the solder portions 32a and 33a is prepared. This completes the operation in step S10 and completes the substrate preparation process (no solder portion).

  In step S11, as shown in FIG. 11, each solder contact portion 41 of the heat conductive sheet 40 is disposed on each ground pad 32 of the circuit board 80, and as shown by an arrow (6) in FIG. The solder material H (see the shaded portion in the figure) is supplied from the application nozzle PN and applied onto the pad 32 and the signal line pad 33. Thereby, the work in step S11 is completed, and the heat conducting member arrangement / solder application process is completed. Here, the heat conduction member arrangement / solder application step in step S11 constitutes the heat conduction member setting step in the present invention.

  In the fifth embodiment, the solder melting process in step S6 is performed first, and the cable setting process in step S5 is performed later. Therefore, before the solder part 32a melted in step S6 is cured, the process proceeds to the next step S5.

  In the fifth embodiment formed as described above, the same operational effects as those of the first embodiment can be obtained.

  Next, a sixth embodiment of the present invention will be described in detail with reference to the drawings. Note that portions having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 12 is a flowchart showing the assembly procedure of the connection structure according to the sixth embodiment, and FIG. 13 is a perspective view for explaining the procedure for removing the heat conductive sheet according to the sixth embodiment.

  As shown in FIG. 12, the assembly procedure of the connection structure 10 in the sixth embodiment is different in that step S20 is additionally performed after step S6 (see FIG. 4) in the first embodiment.

  In step S20, the heat conductive sheet 40 is finally removed as shown by the arrow (7) in FIG. Thereby, the operation | work in step S20 is complete | finished and a heat conductive member removal process is completed. Here, the heat conductive sheet 40 in the sixth embodiment is excellent in heat conductivity instead of the copper heat conductive sheet 40 according to the first embodiment, while the heat of aluminum is lower in solder wettability than copper. A conductive sheet 40 is used. The solder parts 32a are sufficiently melted by the heat transferred from the heat conductive sheet 40 to the ground pads 32, and the subsequent removal work is facilitated.

  Also in the sixth embodiment formed as described above, the same operational effects as in the first embodiment described above can be achieved. In addition to this, in the sixth embodiment, since the heat conductive sheet 40 is removed, the appearance of the connection structure 10 can be improved, and the connection structure 10 can be reduced in weight. Further, by increasing the durability of the heat conductive sheet 40, the heat conductive sheet 40 can be reused, and thus the manufacturing cost of the connection structure 10 can be reduced.

  It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in each of the above embodiments, the four differential signal transmission cables 20 are arranged on the circuit board 30 so as to be arranged at equal intervals at a narrow pitch, but the present invention is not limited to this. . For example, the differential signal transmission cables 20 may be divided into two, and a gap may be formed between them, and a heating jig may be brought into contact with the heat conductive sheet disposed in the gap portion. In this case, each solder part 32a can be melted more quickly, and productivity can be improved.

  In the first to fifth embodiments, the heat conductive sheet 40 is mounted on the circuit board 30 and then left without being processed. However, the present invention is not limited to this. For example, the connection structure 10 is used such that the transmission direction of the two differential signal transmission cables 20 is positive and the transmission direction of the other two differential signal transmission cables 20 is negative. In the case of performing, the heat conductive sheet 40 may be divided at a portion where the transmission direction is different. In this case, it is possible to suppress the occurrence of crosstalk between the signals due to different transmission directions, and improve the reliability.

DESCRIPTION OF SYMBOLS 20 Differential signal transmission cable 21 Signal line conductor 22 Insulator 23 External conductor 30 Circuit board 32 Ground pad 32a Solder part 40 Thermal conduction sheet (thermal conduction member)
41 Solder contact portion 42 Heating jig contact portion 50 Solder contact portion 60 Solder contact portion 70 Fixed pin (fixed convex portion)
71 Fixing hole (fixing recess)
HT1 heating jig

Claims (8)

A cable preparation step of preparing a differential signal transmission cable comprising a pair of signal line conductors, an insulator provided around the signal line conductor, and an external conductor provided around the insulator;
A board preparation step of preparing a circuit board having a ground pad to which the outer conductor is connected;
A heat conduction member preparing step of preparing a heat conduction member that is in contact with a solder portion provided on the ground pad and that heats the solder portion from a position;
A heat conducting member setting step for bringing the heat conducting member into contact with the solder part; and
A cable setting step for bringing the outer conductor into contact with the solder portion;
A solder melting step of heating the heat conducting member and melting the solder portion;
A method for connecting a differential signal transmission cable and a circuit board. In the connection method of the differential signal transmission cable and the circuit board according to claim 1,
A method of connecting a differential signal transmission cable and a circuit board, wherein a heat conducting member removing step of removing the heat conducting member is performed after connecting the external conductor and the ground pad. A differential signal transmission cable having a pair of signal line conductors, an insulator provided around the signal line conductor, and an outer conductor provided around the insulator;
A circuit board having a ground pad to which the outer conductor is connected, and a solder portion provided on the ground pad;
A heat contact member provided with a solder contact portion that is in contact with the solder portion, and a heating jig contact portion that is provided at a position away from the solder contact portion and that contacts the heating jig and applies heat to the solder contact portion; ,
A structure for connecting a differential signal transmission cable and a circuit board. In the connection structure of the differential signal transmission cable and the circuit board according to claim 3,
A structure for connecting a differential signal transmission cable and a circuit board, wherein the heat conducting member is provided with a plurality of the solder contact portions, and the heating jig contact portions are provided on both sides of the solder contact portions. In the connection structure of the differential signal transmission cable and the circuit board according to claim 3 or 4,
A connection structure between a differential signal transmission cable and a circuit board, wherein the solder contact portion is formed in a cutout shape that opens a part of the periphery of the solder portion. In the connection structure of the differential signal transmission cable and the circuit board according to claim 3 or 4,
A connection structure between a differential signal transmission cable and a circuit board, wherein the solder contact portion is formed in a shape surrounding the entire circumference of the solder portion. In the connection structure of the differential signal transmission cable and the circuit board according to claim 3 or 4,
A structure for connecting a differential signal transmission cable and a circuit board, wherein the solder contact portion is formed in a mesh shape through which the molten solder portion passes. In the connection structure of the differential signal transmission cable and the circuit board according to any one of claims 3 to 7,
Either one of the heat conducting member or the circuit board is provided with a fixed protrusion that protrudes toward the other of the heat conducting member or the circuit board, and the other of the heat conducting member or the circuit board. A connection structure between the differential signal transmission cable and the circuit board, in which a fixed recess into which the fixed projection is inserted is provided.

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