Connectors

Abstract

To provide a connection body capable of suppressing reduction of differential impedance and crosstalk between transmission lines.SOLUTION: A connection body comprises: an insulation wire including an insulation layer covering a plurality of conductors disposed while being spaced apart from each other and peripheral surfaces of the plurality of conductors on a peripheral surface basis or collectively; a printed wiring board including a substrate and a plurality of wires disposed while being spaced on the substrate; and a connection section disposed on the substrate and electrically connecting the plurality of conductors and the plurality of wires. The plurality of conductors is exposed in a tip end region in an extension direction of the plurality of conductors, and the tip end region is disposed linearly and overlapped to the plurality of wires in one-to-one correspondence in the connection section. One or more ground layers are provided in parallel with the wires in an inner layer of the substrate, and a distance D in which the tip end region of the plurality of conductors is not indirectly opposed with any ground layer is 0.5 mm or less.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a connector. [Background technology]

[0002] When transmitting an electrical signal (hereinafter also referred to as "signal") to a printed wiring board or the like of an electronic device, an insulated wire such as a flexible flat cable (hereinafter also referred to as "FFC") may be used, and multiple conductors of this insulated wire may be electrically connected to multiple wirings of the printed wiring board.

[0003] When these insulated wires are connected to a printed wiring board via a connector, problems such as reduced noise resistance and reduced impedance arise. Therefore, a mounting structure in which the insulated wires are electrically connected directly to the printed wiring board has been proposed (see JP 2013-196938 A). An example of such a mounting structure is a connection structure 10 in which a printed wiring board 9 is connected to a flexible flat cable 6 disposed on the surface of the printed wiring board 9, as shown in FIG. 1. In the connection structure 10, the tip of the conductor 4 exposed from the insulating layer 7 of the flexible flat cable 6 is solder-connected to a plurality of wirings 2 disposed on a flat substrate 8 of the printed wiring board 9, on which a first ground layer 5 and a second ground layer 15 are provided. Furthermore, the tip of the conductor 4 exposed from the insulating layer of the flexible flat cable 6 disposed on the surface of the printed wiring board 9 is bent at two points so that the lower surface of the tip of the conductor 4 can be bonded to the upper surface of the wirings 2, as shown in FIG. 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-196938 Summary of the Invention

[0005] A connector according to one embodiment of the present disclosure is a connector of an insulated wire and a printed wiring board, comprising: an insulated wire having a plurality of conductors arranged at intervals from one another and an insulating layer covering the peripheral surfaces of the plurality of conductors individually or collectively; a printed wiring board having a substrate and a plurality of wirings arranged at intervals on the substrate; and a connection portion arranged on the substrate and electrically connecting the plurality of conductors and the plurality of wirings, wherein the plurality of conductors are exposed at tip regions in the extension direction of the plurality of conductors, the tip regions are arranged linearly and are superimposed on the plurality of wirings in a one-to-one correspondence at the connection portion, one or more ground layers are provided on an inner layer of the substrate parallel to the wirings, and the distance D at which the tip regions of the plurality of conductors do not indirectly face any of the ground layers is 0.5 mm or less. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a connector according to a conventional embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a connector according to a conventional embodiment. [Figure 3] FIG. 3 is a schematic perspective view showing a connector according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic plan view showing a connector according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a cross-sectional view taken along the line AA in FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view showing the connection body of Comparative Example 2, similar to FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a connector according to another embodiment. [Figure 8] FIG. 8 is a graph showing the simulation results of the change in differential impedance in Example 1, Comparative Example 1, and Comparative Example 2. [Figure 9] FIG. 9 is a graph showing the simulation results of near-end crosstalk in Example 1 and Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0007] [Problem to be solved by this disclosure] Here, when transmitting signals, transmission methods such as parallel transmission, serial transmission, and differential transmission are used, but among these, differential transmission is considered to be advantageous in terms of increasing communication speed.

[0008] However, when manufacturing a connector having a connection portion such as that shown in FIG. 1, multiple conductors of a flexible flat cable are connected together by crimping the cable while melting the solder using a heat bar. In such crimping connections using a heat bar, heat applied to the connection portion may be conducted to the flexible flat cable, potentially deforming the tip of the conductor. For example, as shown in connector 20 in FIG. 2, heat conducted to flexible flat cable 16 may soften the insulating layer 17 of flexible flat cable 16, potentially causing the tip of conductor 14 to move downward. If the tip of conductor 14 exposed from the insulating layer of flexible flat cable 6 arranged on the surface of printed wiring board 9 moves downward, the thickness of insulating layer 17 disposed between conductor 14 of flexible flat cable 16 and substrate 8 of printed wiring board 9 will fluctuate. Such fluctuations in the thickness of insulating layer 17 can significantly change the differential impedance. That is, the differential impedance at the connection between the multiple conductors 14 of the flexible flat cable 16 and the multiple wirings 2 of the printed wiring board 19 is relatively lower than the differential impedance at the portion of the conductors 14 alone and the portion of the wirings 2 alone (such a decrease in differential impedance is also called "differential impedance mismatch"), which may result in transmission loss at the connection. Furthermore, when electrical connection is made by arranging multiple conductors in parallel in the conductor width direction, as in the connection portion of a flexible flat cable, it is necessary to reduce crosstalk between the transmission lines.

[0009] The present disclosure has been made in light of the above circumstances, and has an object to provide a connector that can suppress a decrease in differential impedance and crosstalk between transmission lines.

[0010] [Effects of this disclosure] According to the present disclosure, a connector can be provided that can suppress a decrease in differential impedance and crosstalk between transmission lines.

[0011] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0012] A connector according to one embodiment of the present disclosure is a connector of an insulated wire and a printed wiring board, comprising: an insulated wire having a plurality of conductors arranged at intervals from one another and an insulating layer covering the peripheral surfaces of the plurality of conductors individually or collectively; a printed wiring board having a substrate and a plurality of wirings arranged at intervals on the substrate; and a connection portion arranged on the substrate and electrically connecting the plurality of conductors and the plurality of wirings, wherein the plurality of conductors are exposed at tip regions in the extension direction of the plurality of conductors, the tip regions are arranged linearly and are superimposed on the plurality of wirings in a one-to-one correspondence at the connection portion, one or more ground layers are provided on an inner layer of the substrate parallel to the wirings, and the distance D at which the tip regions of the plurality of conductors do not indirectly face any of the ground layers is 0.5 mm or less.

[0013] In this connector, the tip regions of the conductors exposed from the insulating layer of the insulated wires are arranged in a straight line. This prevents the tip regions of the conductors from moving downward due to softening of the insulating layer, even when crimping is performed using a heat bar to connect multiple conductors at once. This reduces fluctuations in the thickness of the insulating layer disposed between the conductors of the insulated wires and the substrate of the printed wiring board. As a result, a decrease in differential impedance at the connection can be suppressed. Furthermore, one or more ground layers are provided in parallel to the wiring on the inner layer of the substrate, and the distance D, at which the tip regions of the conductors do not indirectly face any of the ground layers, is 0.5 mm or less, thereby effectively reducing crosstalk between the transmission lines. Therefore, the connector can suppress both a decrease in differential impedance and crosstalk between the transmission lines. Here, the "extension direction of the conductor" refers to the direction of current flow in the conductor, and this "extension direction of the conductor" corresponds to the longitudinal direction of the conductor. As will be described later, "the distance D, at which the conductors do not indirectly face any of the ground layers, is 0.5 mm or less" also includes a case where there is no case where the conductors do not indirectly face any of the ground layers, i.e., a case where D=0.

[0014] It is preferable that the ground layer extends to the end face of the board on the connection side. By extending the ground layer to the end face of the board on the connection side, a sufficient range can be secured in which the tip regions of the plurality of conductors and any of the ground layer can indirectly face each other. Therefore, crosstalk between the transmission lines at the connection part can be reduced.

[0015] The distance D, which is the distance at which the tip regions of the conductors do not indirectly face any of the ground layers, is preferably 0.05 mm or more and 0.5 mm or less. By setting the distance D to 0.05 mm or more and 0.5 mm or less, a sufficient range can be secured in which the tip regions of the conductors can indirectly face any of the ground layers. Therefore, crosstalk between the transmission lines at the connection portion of the connector can be further reduced.

[0016] The substrate may have a configuration in which a step is formed on the end surface of the connection portion side of the substrate, with the lower portion protruding more than the upper portion, at least a portion of the end surface of the upper portion of the substrate facing the connection portion side and at least a portion of the end surface of the insulating layer facing the connection portion side, one or more ground layers are arranged on the lower portion of the substrate, and at least one of the ground layers arranged on the lower portion of the substrate indirectly faces the tip regions of the plurality of conductors. By having one or more ground layers arranged on the lower portion of the substrate, and at least one of the ground layers arranged on the lower portion of the substrate indirectly facing the tip regions of the plurality of conductors, the tip regions of the plurality of conductors can be reliably indirectly faced to any of the ground layers. Therefore, crosstalk between the transmission lines at the connection portion can be reduced.

[0017] [Details of the embodiments of the present disclosure] Hereinafter, an embodiment of a connector according to the present disclosure will be described in detail with reference to the drawings.

[0018] <connector> The connector is a connector for an insulated wire and a printed wiring board, and includes an electrical connection structure between the insulated wire, which has a plurality of conductors arranged at intervals from one another and an insulating layer covering the circumferential surfaces of the plurality of conductors individually or collectively, and a plurality of wirings in a printed wiring board, which has a substrate and a plurality of wirings arranged at intervals on the substrate.

[0019] 3 to 5 , a connecting body 100 of this embodiment is a connecting body between an insulated wire 50 and a printed wiring board 1. The connecting body 100 includes an insulated wire 50 having a plurality of conductors 24 arranged at intervals from one another and an insulating layer 7 collectively covering the peripheral surfaces of the plurality of conductors 24, a printed wiring board 1 having a substrate 18 and a plurality of wires 2 arranged at intervals on the substrate 18, and a connecting portion 60 arranged on the substrate 18 and electrically connecting the plurality of conductors 24 and the plurality of wires 2. In the connecting body 100, the insulated wire 50 is not disposed on the surface of the printed wiring board 1, and a portion of an end face 71 of the insulating layer 7 of the insulated wire 50 on the connecting portion 60 side faces a portion of an end face 38 of the printed wiring board 18 on the connecting portion 60 side.

[0020] The plurality of conductors 24 are arranged in an exposed state from the end of the insulating layer 7 toward the tip ends of the plurality of wirings 2. The tip ends of the plurality of conductors 24 are overlapped with the tip ends of the plurality of wirings 2 in a one-to-one correspondence to form an electrical connection portion 60.

[0021] <Insulated wire> The insulated wire 50 has a plurality of conductors 24 arranged side by side with a gap between them. More specifically, the plurality of conductors 24 are arranged substantially parallel to one another in the same plane. "Substantially parallel" means that the angle between the central axes is within ±10°.

[0022] 3 to 5, the insulated wire 50 has a plurality of conductors 24 and an insulating layer 7 that collectively covers the circumferential surfaces of the plurality of conductors 24. The number of the plurality of conductors 24 is not particularly limited. Although FIGS. 3 and 4 show an embodiment in which the plurality of conductors 24 are arranged at equal intervals, this interval can be set appropriately depending on the intervals between the plurality of wires 2 of the printed wiring board 1, design specifications, etc., and the plurality of conductors 24 do not have to be arranged at equal intervals.

[0023] In the connection body 100 of this embodiment, the insulated wire 50 is not disposed on the surface of the printed wiring board 1, and a portion of the end face 71 of the insulating layer 7 of the insulated wire 50 facing the connection portion 60 faces a portion of the end face 38 of the substrate 18 of the printed wiring board 1 facing the connection portion 60. In the connection body 100 of this embodiment, the insulated wire 50 and the substrate 18 are disposed in this manner, so that the tip regions of the conductors 24 of the insulated wire 50 are linearly arranged. In the connection body 100, the tip regions of the conductors 24 exposed from the insulating layer 7 of the insulated wire 50 are linearly arranged. Therefore, even when crimping is performed using a hot bar via solder to electrically connect multiple conductors 24 at once, the tip regions of the conductors 24 are less likely to move downward due to softening of the insulating layer 7. This reduces fluctuations in the thickness of the insulating layer 7 disposed between the conductors 24 of the insulated wire 50 and the substrate 18 of the printed wiring board 1. As a result, a decrease in differential impedance at the connection portion 60 can be suppressed.

[0024] 3 to 5, the insulated wire 50 is a flexible flat cable (FFC) having a plurality of conductors 24 and an insulating layer 7 that collectively covers the circumferential surfaces of the plurality of conductors 24. The connector may employ an insulated wire other than a flexible flat cable that includes a plurality of conductors and a covering layer that covers each of the circumferential surfaces of the plurality of conductors.

[0025] (conductor) The conductors 24 are not particularly limited, and metal wires such as copper, copper alloy, aluminum, and aluminum alloy can be used. Such metal wires may be solid wires or twisted wires. In the case of twisted wires, the number of strands is not particularly limited, but is, for example, between 2 and 30. As shown in FIGS. 3 to 5, each conductor 24 exposed from the insulating layer 7 is connected to each wiring 2 by an electrical connection, which will be described later.

[0026] The cross-sectional shape of the metal wire forming the conductor 24 is not particularly limited, and various shapes such as a circle, a square, or a rectangle can be adopted.

[0027] The lower limit of the average thickness of the conductor 24 (or the average diameter when the cross section is circular) is preferably 10 μm, more preferably 15 μm. On the other hand, the upper limit of the average thickness is preferably 500 μm, more preferably 400 μm. If the average thickness is less than the lower limit, the conductor 24 may be prone to breakage. On the other hand, if the average thickness of the conductor 24 exceeds the upper limit, the connecting body 100 may be unnecessarily large. The average thicknesses of the multiple conductors 24 may be the same or different from one another. Note that the "average thickness" is the average value of thicknesses measured at any five points in the extension direction (longitudinal direction) of the conductor 24. Hereinafter, "average thickness" has the same meaning.

[0028] The lower limit of the average width (average diameter when the cross section is circular) of the conductor 24 in a direction perpendicular to the extension direction in a plan view (hereinafter also referred to as the "width direction") is preferably 10 μm, more preferably 15 μm. On the other hand, the upper limit of the average width is preferably 500 μm, more preferably 400 μm. If the average width is less than the lower limit, the conductor 24 may be prone to breakage. On the other hand, if the average width of the conductor 24 exceeds the upper limit, the connecting body 100 may be unnecessarily large. The average widths of multiple conductors 24 may be the same or different. The "average width" is the average value of widths measured at any five points in the extension direction (longitudinal direction) of the conductor 24. Hereinafter, "average width" has the same meaning.

[0029] The average exposed length of the conductor 24 from the insulating layer 7 is, for example, 0.2 mm or more and 5.0 mm or less. The "average exposed length" of the conductor 24 is the average value of the lengths in the extension direction measured at any five points in the width direction of the exposed portion (tip end) of the conductor 24.

[0030] The average spacing between adjacent conductors 24 can be set appropriately according to the average spacing between wirings 2, which will be described later.

[0031] In this embodiment, the printed wiring board 1 has a plurality of signal lines as the plurality of wirings 2, but it may also have a plurality of signal lines and a plurality of ground lines as the plurality of wirings 2. For example, it may have a plurality of wirings (for example, four) in which the two outermost wirings of the plurality of wirings are ground lines and the remaining inner wirings (for example, two wirings) are signal lines.

[0032] (insulating layer) The insulating layer 7 is laminated on the peripheral surface of the conductor 24 so as to cover the conductor 24. The insulating layer 7 may have a single layer structure or a multi-layer structure of two or more layers.

[0033] As described above, in the insulated wire 50 of the present embodiment, the circumferential surfaces of the plurality of conductors 24 are collectively coated with the insulating layer 7. However, the insulated wire may also be configured such that the circumferential surfaces of the plurality of conductors 24 are individually coated with the insulating layer 7. That is, the circumferential surfaces of the plurality of conductors 24 may each be coated with the insulating layer 7.

[0034] The material of the insulating layer 7 is not particularly limited as long as it has insulating properties and flexibility, and examples that can be used include ethylene resins such as polyethylene, ethylene vinyl acetate copolymer, and ethylene ethyl acrylate copolymer; resins obtained by blending ethylene resin with polyolefins such as polypropylene, ethylene propylene rubber, and styrene elastomer; polyester resins such as PET (polyethylene terephthalate); polyimide, polyamideimide, polyesterimide, silane crosslinkable resin compositions; and fluororesins such as PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), and FEP (perfluoroethylenepropene copolymer).

[0035] The insulating layer 7 can be coated on the conductors 24 by, for example, extruding molten resin onto the peripheral surfaces of the plurality of conductors 24 and hardening it, or by applying a paint made by dissolving the resin in an organic solvent onto the peripheral surfaces of the conductors 24 and baking it.

[0036] The average thickness (wall thickness) of the insulating layer 7 is not particularly limited, but can be, for example, 3 μm or more and 1 mm or less.

[0037] The insulating layer 7 may have a primer layer in contact with the conductor 24. This primer layer can be preferably made of a cured crosslinkable resin such as ethylene that does not contain metal hydroxide. By providing such a primer layer, it is possible to prevent deterioration over time in the peelability between the insulating layer 7 and the conductor 24.

[0038] <Printed wiring board> 3 to 5, printed wiring board 1 has an insulating substrate 18 and a plurality of wirings 2 formed as a plurality of layers laminated on the surface of substrate 18. A plurality of conductors 24 of insulated wire 50 are superimposed on these plurality of wirings 2 in a one-to-one correspondence to form connection portion 60.

[0039] (substrate) The substrate 18 of the printed wiring board 1 is made of an insulating plate-like material. The plate-like material constituting the substrate 18 may be a rigid substrate or a flexible substrate. Specifically, a resin plate can be used as the rigid substrate. Suitable materials for the resin plate include, for example, a substrate made of glass cloth impregnated with epoxy resin (glass epoxy) and a substrate made of glass cloth impregnated with polyphenylene ether (PPE). Specifically, a resin film can be used as the flexible substrate. Suitable materials for the resin film include, for example, polyimide, polyethylene terephthalate, and PPE. The substrate 18 may contain fillers, additives, and the like. The dielectric constant of the substrate 18 is typically about 3 to 5. For example, the dielectric constant of the glass epoxy is about 4 to 5, and the dielectric constant of the PPE is about 3 to 4.

[0040] The average thickness of the substrate 18 is set appropriately depending on the design concept, etc. For example, if the average thickness of the substrate 18 is too small, the strength of the substrate 18 may be insufficient. On the other hand, if the average thickness of the substrate 18 is too large, the connecting body 100 may be unnecessarily thick. Therefore, for example, the average thickness of the substrate 18 can be set appropriately taking these points into consideration along with the design concept.

[0041] (wiring) The plurality of wires 2 (more specifically, the tips of the plurality of wires 2) are arranged side by side on the substrate 18 with a gap between them. Specifically, the plurality of wires 2 are arranged substantially parallel to one another on the substrate 18. These wires 2 are formed into a desired planar shape (pattern) by, for example, etching a metal layer laminated on the surface of the substrate 18. The plurality of wires 2 are each formed into a rectangular shape in a plan view and are arranged substantially parallel to one another.

[0042] Each wire 2 can be made of a conductive material, but is generally made of copper, for example. The surface of the wire 2 may be plated. For example, the wire 2 may be covered with a pre-soldering portion (not shown). As the plating, tin plating, gold plating, or solder plating is preferred.

[0043] The lower limit of the average thickness of the wiring 2 is preferably 8 μm, more preferably 15 μm. The upper limit of the average thickness of the wiring 2 is preferably 100 μm, more preferably 70 μm. If the average thickness of the wiring 2 is less than the lower limit, the conductivity may be insufficient. On the other hand, if the average thickness of the wiring 2 exceeds the upper limit, the connector 100 may become unnecessarily thick.

[0044] The lower limit of the average width of the wiring 2 is preferably 0.8 times, and more preferably 1 time, the average width of the conductor 24 of the insulated wire 50. The upper limit of the average width of the wiring 2 is preferably 5 times, more preferably 3 times, and more preferably 2 times the average width of the conductor 24. If the average width of the wiring 2 is less than the above lower limit, it may not be easy to connect the conductor 24. On the other hand, if the average width of the wiring 2 exceeds the above upper limit, the width of the connector 100 may be unnecessarily large.

[0045] More specifically, the lower limit of the average width of the wiring 2 is preferably 50 μm, more preferably 75 μm, while the upper limit of the average width of the wiring 2 is preferably 800 μm, more preferably 600 μm.

[0046] The average spacing between adjacent wirings 2 can be, for example, 0.5 to 5 times the average diameter of the conductor 24. The average spacing between wirings 2 means the average value of spacing measured at any five points in the extension direction.

[0047] More specifically, the lower limit of the average spacing between adjacent wirings 2 is preferably 50 μm, more preferably 75 μm, while the upper limit of the average spacing between adjacent wirings 2 is preferably 500 μm, more preferably 400 μm.

[0048] The average intervals between adjacent wirings 2 may be the same (equidistant) or may be different.

[0049] (Connection) The connection portion 60 is formed by electrically connecting the tip of the conductor 24 with the wiring 2. The plurality of conductors 24 and the plurality of wirings 2 are electrically connected by the connection portion 60. By electrically connecting the tip of the conductor 24 with the wiring 2, the tip of the conductor 24 is more reliably connected with the wiring 2. Examples of electrical connection methods using pressure bonding with a heat bar include connection by solder (solder connection), connection by anisotropic conductive film, and connection by anisotropic conductive paste.

[0050] <Solder connection> In soldering, objects are electrically connected by melting solder. The solder used for soldering is not particularly limited, but lead-free solder such as SnAgCu alloy, SnZnBi alloy, SnCu alloy, and SnAgInBi alloy can be used.

[0051] <Connection using anisotropic conductive film> Connections using anisotropically conductive films are made by thermally curing the anisotropically conductive film that acts as an adhesive to electrically connect objects. Anisotropically conductive films are film-like adhesives in which conductive particles are dispersed in an adhesive component containing, for example, a thermoplastic resin or a thermosetting resin. When anisotropically conductive films are heated and pressurized with a heat bar, the particles dispersed in the adhesive component are interposed between the objects to establish an electrical connection, while the adhesive bonds the two objects together, maintaining the connection structure.

[0052] <Connection using anisotropic conductive paste> Connections using anisotropic conductive paste are made by thermally hardening the anisotropic conductive paste, which acts as an adhesive, to electrically connect objects. Anisotropic conductive paste is a one-component, heat-hardening liquid composition with conductive particles dispersed in it. Like anisotropic conductive film, anisotropic conductive paste establishes an electrical connection by having particles dispersed in the adhesive component interpose between the objects, while the adhesive maintains the connection structure by bonding the two objects together.

[0053] (Ground layer) In the printed wiring board 1, one or more ground layers are provided in parallel to the above-mentioned wiring on the inner layer of the substrate 18. In this embodiment, a first ground layer 25 and a second ground layer 35 are provided on the inner layer of the substrate 18.

[0054] It is preferable that at least one ground layer extends to the end face 38 of the substrate 18 on the connection portion 60 side. Extending at least one ground layer to the end face 38 of the substrate 18 on the connection portion 60 side ensures a sufficient range in which the tip regions of the plurality of conductors 24 and at least one ground layer can indirectly face each other. This reduces crosstalk between the transmission lines at the connection portion 60. In the present embodiment shown in FIG. 5 , the first ground layer 25 and the second ground layer 35 extend to the end face 38 of the substrate 18 on the connection portion 60 side. However, either the first ground layer 25 or the second ground layer 35 may extend to the end face 38 of the substrate 18 on the connection portion 60 side. Furthermore, the more ground layers that indirectly face the tip regions of the plurality of conductors, the more preferable.

[0055] The distance D at which the tip regions of the conductors 24 do not indirectly face any of the ground layers is 0.5 mm or less. By setting the distance D at which the tip regions of the conductors 24 do not indirectly face any of the ground layers to 0.5 mm or less, a sufficient range can be secured in which the tip regions of the conductors 24 can indirectly face any of the ground layers. Therefore, crosstalk between the transmission lines at the connection portion 60 of the connecting body 100 can be further reduced. Meanwhile, the distance D at which the tip regions of the conductors 24 do not indirectly face any of the ground layers is preferably 0.05 mm or more. Setting the distance D to 0.05 mm or more can further enhance the effect of reducing crosstalk between the transmission lines. Note that "the distance D at which the conductors do not indirectly face any of the ground layers is 0.5 mm or less" also includes a case in which there is no case in which the conductors do not indirectly face any of the ground layers, i.e., a case in which D=0. Examples of the above-mentioned form where D=0 include a form in which the end face of the substrate on the connection side and the end face of the insulating layer on the connection side are in contact with each other, and a form shown in FIG. 7, which will be described later.

[0056] [Method of manufacturing connector] The method for manufacturing the connector includes the steps of preparing an insulated wire, preparing a printed wiring board, and electrically connecting the conductors of the insulated wire to the wiring of the printed wiring board. The insulated wire may be prepared by a known method in the step of preparing the insulated wire. The printed wiring board 1 may be prepared by a known method in the step of preparing the printed wiring board.

[0057] The process of electrically connecting the multiple conductors of the insulated wire and the multiple wirings of the printed wiring board can be carried out using the known method described above. For example, the multiple conductors and the multiple wirings are overlapped and pressed with a heat bar to melt the solder, adhesive, etc. and crimp the multiple conductors and the multiple wirings together.

[0058] The components of the connection body obtained by the above manufacturing method are as described above.

[0059] This connector can suppress a decrease in differential impedance and crosstalk between transmission lines.

[0060] [Other embodiments] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is not limited to the configurations of the above-described embodiments, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0061] In another embodiment of the connector, the end surface of the substrate facing the connection portion may have a step formed such that the lower portion protrudes more than the upper portion, at least a portion of the end surface of the upper portion of the substrate facing the connection portion may face at least a portion of the end surface of the insulating layer facing the connection portion, and one or more ground layers may be disposed in the lower portion of the substrate, with at least one of the ground layers disposed in the lower portion of the substrate indirectly facing the tip regions of the plurality of conductors. By disposing one or more ground layers in the lower portion of the substrate and at least one of the ground layers disposed in the lower portion of the substrate indirectly facing the tip regions of the plurality of conductors, the tip regions of the plurality of conductors can be reliably indirectly facing any of the ground layers. Therefore, crosstalk between the transmission lines at the connection portion can be reduced.

[0062] FIG. 7 is a schematic cross-sectional view showing a connecting body of another embodiment, illustrating an example of another embodiment in which the distance D, where the tip region of the conductor does not indirectly face any of the ground layers, is 0. As shown in FIG. 7 , connecting body 200 of this embodiment is a connecting body between insulated wire 50 and printed wiring board 80. Connecting body 200 includes insulated wire 50 having multiple conductors 24 arranged at intervals from one another and insulating layer 7 collectively covering the peripheral surfaces of the multiple conductors 24; printed wiring board 80 having substrate 28 and multiple wirings 2 arranged at intervals on substrate 28; and connecting portion 70 arranged on substrate 28 and electrically connecting the multiple conductors 24 and the multiple wirings 2. In connecting body 200, a step is formed on the end face of substrate 28 facing connecting portion 70, with the lower step protruding more than the upper step, and end face 48 of the upper step of the step of substrate 28 faces a portion of end face 71 of insulating layer 7 facing connecting portion 70. Furthermore, a first ground layer 45 and a second ground layer 55 are provided on an inner layer of the substrate 28 in parallel to the wiring 2, and the second ground layer 55 extends to an end face 58 of a lower portion of the substrate 28. An end face 71 of an upper portion of the step of the substrate 28 faces an end face 71 of the insulating layer 7 on the connection portion 70 side, and the first ground layer 45 and the second ground layer 55 extend to the end face 58 of the lower portion of the substrate 28. Since the first ground layer 45 and the second ground layer 55 indirectly face the tip regions of the plurality of conductors 24 in this manner, crosstalk between the transmission lines at the connection portion 70 can be reduced. Note that, in another embodiment shown in FIG. 7 , the first ground layer 45 and the second ground layer 55 extend to the end face 58 of the lower portion of the substrate 28, but either the first ground layer 45 or the second ground layer 55 may extend to the end face 58 of the substrate 28 on the connection portion 70 side. Also in the other embodiment shown in FIG. 7, it is preferable to have as many ground layers indirectly facing the tip end region of the conductor as possible.

[0063] The connector may include a resin layer (UV-cured resin) covering the connection portion. In this case, the relative dielectric constant of the resin layer is preferably smaller than that of the substrate. When the relative dielectric constant of the resin layer is smaller than that of the substrate, transmission loss at the connection portion can be suppressed. For example, the relative dielectric constant of the resin layer is preferably 2 or more and 3 or less, and can be appropriately set within this numerical range so that the relative dielectric constant of the resin layer is smaller than that of the substrate. Examples of materials for such a resin layer include ultraviolet (UV)-cured resins. Examples of UV-cured resins include acrylic resins and bismaleimide resins. [Example]

[0064] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0065] Example 1 A connection structure of an insulated wire and a printed wiring board similar to the embodiment shown in FIGS. 3 to 5 was produced as a connection structure of Example 1.

[0066] The connector of Example 1 used a substrate with seven conductors with an average diameter of 0.048 mm and seven wires with an average thickness of 0.048 mm formed on its surface, and with first and second ground layers extending to the end face on the connection side as inner layers. The seven conductors and seven wires were arranged as GSSGSSG, where G represents the ground line and S represents the signal line. The average thickness of the first ground layer was 0.035 mm, and the average thickness of the second ground layer was 0.018 mm. The average thickness between the wires and the first ground layer was 0.15 mm, and the average thickness between the first and second ground layers was 0.20 mm.

[0067] The insulated wire was a flexible flat cable with a single conductor having a circular cross section and an average diameter of 0.2 mm, the periphery of which was covered with an insulating layer. The average thickness of the insulating layer was 0.74 mm, and the average thickness from the bottom of the insulating layer to the conductor was 0.27 mm. Aluminum shielding layers with an average thickness of 0.01 mm were provided on the top and bottom surfaces of the insulating layer. The conductor was then crimped to the wiring using Sn-Ag-Cu solder.

[0068] 5, the distance D1 at which the tip regions of the plurality of conductors 24 do not indirectly face any of the ground layers, i.e., the distance between end face 38 of substrate 18 on the connection portion 60 side, which is the tip of the ground layer, and end face 71 of insulating layer 7 on the connection portion 60 side, was set to 0.2 mm. In this way, the connection body of Example 1 was obtained.

[0069] (Comparative Example 1) The insulated wire and the substrate were the same as those used in Example 1. As a conventional technique, a connection was produced as Comparative Example 1, in which the conductor 14 of the flexible flat cable arranged on the substrate 8 was inclined downward by soldering using a heating bar, as shown in Figure 2 above.

[0070] (Comparative Example 2) A connection body 30 of Comparative Example 2 was obtained in the same manner as in Example 1, except that the distance D2 at which the tip regions of the plurality of conductors 24 do not indirectly face any of the ground layers, that is, the distance D2 between the end face 71 of the insulating layer 7 on the connection portion 32 side and the tip 41 of the ground layer 5 and the tip 42 of the ground layer 15, was set to 1.5 mm as shown in Fig. 6. In the connection body 30, the tip 41 of the ground layer 5 and the tip 42 of the ground layer 15 do not extend to the end face 46 of the substrate 8 on the connection portion 32 side.

[0071] [evaluation] (differential impedance) A current was passed from the wiring to the conductor in the connections of Example 1, Comparative Example 1, and Comparative Example 2, and the change in differential impedance at each point over time was simulated. The results are shown in Figure 8. In Figure 8, the region from 70 ps to 130 ps is the region that shows the change in differential impedance at the connection between the wiring of the printed wiring board and the conductor of the insulated wire.

[0072] (near-end crosstalk) A near-end crosstalk simulation was performed by inputting a sweeping electrical signal of 0 GHz to 50 GHz to the connecting bodies of Example 1, Comparative Example 1, and Comparative Example 2. The results are shown in FIG.

[0073] As shown in Figure 8, the connectors of Example 1 and Comparative Example 2, in which the tip regions of the conductors are arranged in a straight line and the thickness of the insulating layer between the conductor and the substrate is constant, showed small changes in differential impedance at the connection. On the other hand, Comparative Example 1, which includes a connector in which the conductor arranged on the substrate is tilted downward, showed a very large change in impedance.

[0074] 9, the connection body of Example 1, in which the distance D1 at which the tip regions of the multiple conductors do not indirectly face any of the ground layers is 0.5 mm or less, had reduced near-end crosstalk in all frequency bands compared to the connection body of Comparative Example 2, in which the distance D2 at which the tip regions of the conductors do not face the ground layer is greater than 0.5 mm. The results of Comparative Example 2 show that even if the change in differential impedance is suppressed, the near-end crosstalk increases as the distance at which the tip regions of the conductors do not face the ground layer increases.

[0075] The above results demonstrate that the connector can suppress a decrease in differential impedance and crosstalk between transmission lines. Therefore, the connector can be applied to connect insulated wires such as signal lines and ground lines, and can be suitably used as a connector for insulated wires and printed wiring boards. [Explanation of symbols]

[0076] 1, 9, 80 Printed wiring board 2 Wiring 4, 14, 24 conductors 5, 25, 45 First ground layer 6, 16 flexible flat cable 7, 17 Insulation layer 8, 18, 28 boards 10, 20, 30, 100, 200 connections 15, 35, 55 Second ground layer 38, 46, 48, 58, 71 End face of board 41, 42 Tip of ground layer 50 Insulated wire 32, 60, 70 Connections 71 Edge of insulating layer D1, D2 The distance at which the tip area of ​​the conductor does not face the ground plane

Claims

1. A connection body of an insulated wire and a printed wiring board, an insulated wire having a plurality of conductors arranged at intervals from one another and an insulating layer covering the circumferential surfaces of the plurality of conductors individually or collectively; a printed wiring board having a substrate and a plurality of wires spaced apart on the substrate; a connection portion disposed on the substrate and electrically connecting the plurality of conductors and the plurality of wirings; Equipped with the plurality of conductors are exposed at tip end regions in the extension direction of the plurality of conductors, the tip region is linearly arranged and overlaps the plurality of wirings in one-to-one correspondence at the connection portion; One or more ground layers are provided in an inner layer of the board in parallel to the wiring in a cross-sectional view, A connector in which the distance D at the tip end regions of the plurality of conductors that do not indirectly face any of the ground layers is 0.05 mm or more and 0.5 mm or less.

2. A connector for an insulated electric wire and a printed wiring board, an insulated wire having a plurality of conductors arranged at intervals from one another and an insulating layer covering the circumferential surfaces of the plurality of conductors individually or collectively; a printed wiring board having a substrate and a plurality of wires spaced apart on the substrate; a connection portion disposed on the substrate and electrically connecting the plurality of conductors and the plurality of wirings; Equipped with the plurality of conductors are exposed at tip end regions in the extension direction of the plurality of conductors, the tip region is linearly arranged and overlaps the plurality of wirings in one-to-one correspondence at the connection portion; A plurality of ground layers are provided in an inner layer of the board in parallel to the wiring in a cross-sectional view, A connector in which the distance D at which the tip end regions of the plurality of conductors do not indirectly face any of the ground layers is 0 mm.

3. A connector for an insulated electric wire and a printed wiring board, an insulated wire having a plurality of conductors arranged at intervals from one another and an insulating layer covering the circumferential surfaces of the plurality of conductors individually or collectively; a printed wiring board having a substrate and a plurality of wires spaced apart on the substrate; a connection portion disposed on the substrate and electrically connecting the plurality of conductors and the plurality of wirings; Equipped with the plurality of conductors are exposed at tip end regions in the extension direction of the plurality of conductors, the tip region is linearly arranged and overlaps the plurality of wirings in one-to-one correspondence at the connection portion; One or more ground layers are provided in an inner layer of the board in parallel to the wiring in a cross-sectional view, a distance D at which the tip end regions of the plurality of conductors do not indirectly face any of the ground layers is 0.5 mm or less; a step is formed on an end surface of the substrate on the connection portion side, with a lower portion protruding more than an upper portion; at least a part of an end surface of the upper part of the substrate on the side of the connection portion faces at least a part of an end surface of the insulating layer on the side of the connection portion; The ground layer is not disposed on the upper part of the board, A connection body in which one or more ground layers are arranged in the lower part of the substrate, and at least one of the ground layers arranged in the lower part of the substrate indirectly faces the tip regions of the plurality of conductors.

4. 4. The connector according to claim 1, wherein at least one of the ground layers extends to an end face of the substrate on the side of the connection portion.

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