High-frequency signal transmission device and method for electrically connecting wiring board and connector

Abstract

The present application provides a kind of high frequency signal transmission device and the electrical connection method of wiring board and connector.In the way of abutting of the ground contact terminal of connector and the ground contact pad of wiring board, there is room for improvement in the high frequency signal transmission characteristics of the device as a whole including the connector in addition to the wiring board.The contact portion (b3) of the arm portion (42b) of the ground contact terminal (46) of the connector (4) is positioned at least partially in contact with the surface of the covering portion (58) of the ground contact pad (P2) covering the first through electrode (28) directly above the first through electrode (28) when the FPC (2) is electrically connected to the connector (4), or is positioned in contact with the ground contact pad (P2) near the periphery of the covering portion (58).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a high-frequency signal transmission device and an electrical connection method of a wiring board and a connector. BACKGROUND

[0002] Patent Document 1 discloses an FPC for high-speed transmission with good impedance matching. In particular, a high-speed transmission path and a ground pattern are formed on one face of a base. A first ground layer is laminated on one face of the base via a dielectric sheet. A second ground layer is laminated on the other face of the base. The above-mentioned ground pattern is electrically connected to the first ground layer and the second ground layer via through-holes. In particular, in this document Figure 5 , a cross-sectional structure of an end portion of the FPC is illustrated.

[0003] In Patent Document 2, a structure in which a back surface ground line is electrically connected via a contact hole is also disclosed (refer to Figure 1 and Figure 2 of this document). In Patent Document 3, a flexible cable is connected to a connector using an adapter.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1 Japanese Patent Application Laid-Open No. 2007-234500

[0007] Patent Document 2 Japanese Patent No. 5580994

[0008] Patent Document 3 Japanese Patent No. 6721845 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] In the manner in which the ground contact terminal of the connector and the ground contact pad of the wiring board are in abutment, there is room for improvement in the high-frequency signal transmission characteristics of the entire device including the connector in addition to the wiring board.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] The high-frequency signal transmission device of one embodiment of the present disclosure includes a connector including a plurality of contact terminals including a plurality of signal contact terminals and a plurality of ground contact terminals arranged regularly, and a wiring board including a plurality of signal contact pads, a plurality of ground contact pads, and one or more ground layers formed at one cable end, the one or more ground layers electrically connected to the ground contact pads via at least one first through electrode that penetrates a dielectric layer of the wiring board. The ground contact terminal includes an arm portion that is bent so as to partially abut against the ground contact pad with a contact portion. The contact portion of the arm portion is positioned (i) at least partially in contact with a surface of a cover portion that covers the first through electrode directly above the first through electrode, or (ii) at least partially in contact with the ground contact pad near a periphery of the cover portion when the wiring board and the connector are electrically connected.

[0013] In some embodiments, the contact terminal group includes a unit arrangement in which two signal contact terminals are sandwiched by two ground contact terminals. Two adjacent ground contact terminals included in adjacent unit arrangements in the width direction of the connector are each positioned (i) at least partially in contact with a surface of at least one common cover portion, or (ii) in contact with the ground contact pad near a periphery of the at least one common cover portion.

[0014] In any combination of the above-described modes, a return loss and / or a fluctuation in an insertion loss are reduced in a high-frequency band (e.g., 20 to 25 GHz).

[0015] In any combination of the above-described modes, the first through electrode is positioned at a position offset in a direction away from a free end of the arm portion, as compared to the contact portion of the arm portion, when the wiring board and the connector are electrically connected.

[0016] In any combination of the above-described modes, a plurality of second through electrodes that penetrate the dielectric layer to electrically connect a ground line formed in the same layer as the ground contact pad to the ground layer are arranged in the same row as the first through electrode at a predetermined interval in the long side direction of the wiring board, and the interval between the first through electrode and the second through electrode directly adjacent thereto is different from the predetermined interval of the plurality of second through electrodes.

[0017] In any combination of the above-described modes, the first through electrode has a cylindrical or conical shape, and the arm portion extends in a tangential direction of the periphery of the cover portion.

[0018] In any combination of the above-described modes, the plurality of signal contact pads and the ground contact pads are arranged in a unit arrangement in which a pair of signal contact pads is sandwiched by two ground contact pads in the width direction of the wiring board, and one ground contact pad is provided between a pair of signal contact pads adjacent in the width direction of the wiring board.

[0019] In any combination of the above-described modes, the wiring board has a plurality of differential signal lines each composed of two signal lines, and a plurality of ground lines formed on both sides of each differential signal line in a manner of sandwiching each differential signal line in the width direction of the wiring board, and one ground line is provided between differential signal lines adjacent in the width direction of the wiring board.

[0020] In any combination of the above-described modes, one first through electrode is assigned with respect to one ground contact pad in order to be electrically connected to the ground layer.

[0021] In any combination of the above-described modes, the one or more ground layers include a plurality of ground layers each extending in the long side direction of the wiring board, and the plurality of ground contact pads are individually electrically connected to the plurality of ground layers via the first through electrodes.

[0022] In any combination of the above-described modes, the wiring board further includes a plurality of ground lines formed in the same layer as the plurality of ground contact pads, and each ground line of the plurality of ground lines is electrically connected to each ground layer of the plurality of ground layers via a plurality of second through electrodes that penetrate the dielectric layer.

[0023] In any combination of the above-described modes, the high-frequency signal transmission device further includes an adapter that supports the cable end of the wiring board and is mechanically coupled to the connector, and the cable end is positioned at a predetermined position in the connector by the mechanical coupling of the connector to the adapter.

[0024] In another mode of the method for electrically connecting the connector to the wiring board of the present disclosure, the connector is configured to support a contact terminal group by an insulator, the contact terminal group is regularly arranged by a plurality of contact terminals including a plurality of signal contact terminals and a plurality of ground contact terminals, and the method for electrically connecting the connector to the wiring board is characterized in that,

[0025] A plurality of signal contact pads, a plurality of ground contact pads, and one or more ground layers are formed at the cable end of at least one of the wiring boards, the one or more ground layers are electrically connected to the ground contact pads via at least one first through electrode that penetrates the dielectric layer,

[0026] The method includes a process of positioning a contact portion of a ground contact terminal (i) at a position at least partially abutting a surface of a cover portion covering a ground contact pad of the first through electrode directly above the first through electrode, or (ii) at a position abutting the ground contact pad near an outer periphery of the cover portion.

[0027] In several embodiments, the contact terminal group includes a plurality of unit arrangements in which two signal contact terminals are sandwiched by two ground contact terminals. Two adjacent ground contact terminals included in unit arrangements adjacent in the width direction of the connector are respectively (i) positioned at positions at least partially abutting a surface of at least one common cover portion, or (ii) positioned at positions abutting the ground contact pad near an outer periphery of the at least one common cover portion.

[0028] Effects of Invention

[0029] According to one embodiment of the present disclosure, the high-frequency signal transmission characteristics of the entire device including the connector in addition to the wiring substrate can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a schematic perspective view of a high-frequency signal transmission device according to one embodiment of the present disclosure, and also illustrates a substrate communicably connected via the high-frequency signal transmission device.

[0031] Figure 2 is a schematic exploded perspective view of a cable end of the FPC on the side of the connector from which the FPC is detached.

[0032] Figure 3 is a schematic perspective view of the opposite side of Figure 2

[0033] Figure 4 is a schematic plan view of the FPC with adapters supporting each cable end of the FPC.

[0034] Figure 5 is a schematic partial plan view of the FPC. The first through electrode is positioned at the width center of the ground contact pad, and the second through electrode is positioned at the width center of the ground line.

[0035] Figure 6 is a schematic partial cross-sectional view of the FPC along the double-dotted line VI-VI of Figure 5

[0036] Figure 7 is a schematic side view of the connector.

[0037] Figure 8 is a schematic plan view of the connector, illustrating an opening of an insertion space for the FPC.

[0038] ​​Figure 9 is a diagram showing a state in which the adapter of the FPC is mechanically coupled with the connector so that the FPC and the connector are electrically connected, and shows a state in which the contact terminals of the connector and the contact pads of the FPC are in abutment, in a partial cross section.

[0039] Figure 10 is a partial diagram showing a state in which the signal contact terminals and the ground contact terminals of the connector are in abutment with the signal contact pads and the ground contact pads of the FPC, respectively, in a state in which the adapter of the FPC is mechanically coupled with the connector so that the FPC and the connector are electrically connected.

[0040] Figure 11 is a simulation result showing improvement in return loss.

[0041] Figure 12 is a simulation result showing improvement in insertion loss.

[0042] Figure 13 is a simulation result showing improvement in near-end crosstalk.

[0043] Figure 14 is a simulation result showing improvement in far-end crosstalk.

[0044] Figure 15 is a diagram of another example in which two ground lines are formed between the differential signal lines.

[0045] Figure 16 is a diagram of another example in which a change is applied to the ground layer. DETAILED DESCRIPTION

[0046] Hereinafter, various embodiments and features of the present disclosure will be described with reference to the accompanying drawings. The skilled person in the art does not need an excessive explanation to combine each embodiment and / or each feature, and can also understand the synergistic effect brought by the combination. Repetitive explanations among the embodiments are omitted in principle. The drawings are simplified for the purpose of drawing mainly for the purpose of describing the invention. Each feature is not effective only for the high-frequency signal transmission device and the method related thereto disclosed in the present specification, but can be understood as a general feature that is also common to other various high-frequency signal transmission devices and the methods related thereto not disclosed in the present specification.

[0047] If referring to Figures 1 to 4The high-frequency signal transmission device 1 has an FPC (Flexible Printed Circuit) 2, adapters 3a, 3b (collectively referred to as adapters 3), and connectors 4a, 4b (collectively referred to as connectors 4). The cable ends 2a, 2b of the FPC 2 are electrically connected to the connectors 4a, 4b, respectively (for example, based on mechanical coupling of the adapters 3a, 3b to the connectors 4a, 4b). The connectors 4a, 4b are mounted to and electrically connected to different substrates 9a, 9b or different substrate portions of the same substrate. In this way, inter-substrate communication via the high-frequency signal transmission device 1 is enabled.

[0048] The FPC 2 is a flexible cable that is one example of a wiring substrate. The FPC 2 can have various shapes, and in addition to extending in one direction with a prescribed width, can extend in a meandering manner or in a manner that traces an S or L. The FPC 2 can also have a width that varies in the direction of extension, and for example, can include narrow portions, wide portions, tapered portions, and the like.

[0049] The FPC 2 has one or more transmission paths 7 for high-frequency signal transmission between the cable ends 2a, 2b thereof. Typically, a plurality of transmission paths 7 are arranged in the width direction of the FPC 2. As will be clear from the description below, a plurality of signal contact pads P1, a plurality of ground contact pads P2, and one or more ground layers 27 are formed at each of the cable ends 2a, 2b of the FPC 2 (see FIG. 2). Figures 4 to 6 The one or more ground layers 27 are electrically connected to the ground contact pads P2 via at least one first through electrode 28 that penetrates a dielectric layer 50. In addition, a slit can be formed between transmission paths 7 that are adjacent in the width direction of the FPC 2.

[0050] The adapters 3a, 3b are each mounted to and support the cable ends 2a, 2b of the FPC 2. The adapter 3 has a main body 31 that is shaped so as to receive the cable ends of the FPC 2, a protruding portion 32 that protrudes from the main body 31 so as to support the cable ends of the FPC 2, and a pair of alignment protrusions 33 that are provided on both sides of the protruding portion 32 so as to sandwich the protruding portion 32. The adapter 3 is shaped so as to be wide in the same direction as the FPC 2. When the adapter 3 is mounted to the FPC 2, the signal contact pads P1 and the ground contact pads P2 of the FPC 2 are arranged between the alignment protrusions 33. The adapters 3a, 3b are mechanically coupled to the connectors 4a, 4b, in which the cable ends 2a, 2b of the FPC 2 are positioned at prescribed locations.

[0051] The connector 4 has an insulator 41 shaped in such a manner that an insertion space 44 into which the cable ends 2a, 2b of the FPC 2 are inserted is given, an arrangement (i.e., a contact terminal group) of contact terminals 42 (there are cases in which signal contact terminals and ground contact terminals are collectively referred to as contact terminals) supported by the insulator 41, and a fixing member 43 for fixing the connector 4 to the substrate 9. The insulator 41 is given a wide shape in the same direction as the FPC 2. In the arrangement of the contact terminals 42, the contact terminals 42 (in detail, signal contact terminals and ground contact terminals) are regularly arranged. More specifically, the same or different kinds of contact terminals 42 that abut on each other in the arrangement direction of the contact terminals 42 (typically, the width direction of the connector 4) are arranged at the same or different pitches. The manner in which the insulator 41 supports the contact terminals 42 can be achieved by various methods such as insert molding, press-in, adhesion, and the like. Furthermore, the insertion space 44 of the insulator 41 has the protruding portion 32 and the alignment protrusion 33 of the adapter 3 inserted therein in addition to the cable ends 2a, 2b of the FPC 2. For this purpose, the insertion space 44 of the insulator 41 is given an appropriate shape.

[0052] A locking protrusion 49 can be provided on the outer surface of the insulator 41 of the connector 4, and a locked portion 39 to be locked by the locking protrusion 49 is provided with respect to the adapter 3 (refer to Figure 3 ). Thereby, it is possible to prevent the adapter 3 from being accidentally detached from the connector 4, and it is possible to improve the positional accuracy of the adapter 3 with respect to the connector 4. It is also possible to provide the locking protrusion to the adapter 3 and the locked portion to the connector 4. It is also possible to provide the locking position of the locking protrusion and the locked portion in two or more positions. Furthermore, it is also possible to directly connect the FPC 2 to the connector 4 without using the adapter 3.

[0053] If referring to Figure 4 and Figure 5 , a plurality of transmission paths 7 are arranged in the width direction of the FPC 2. The transmission path 7 includes a differential signal line 25 constituted by two signal lines 25a, 25b that transmit differential signals, and a pair of ground lines 26 formed on both sides of the differential signal line 25 in such a manner that the differential signal line 25 is sandwiched in the width direction of the FPC 2. The differential signal line 25 (the signal lines 25a, 25b) is formed so as to extend between the cable end 2a and the cable end 2b. Likewise, the pair of ground lines 26 is formed so as to extend between the cable end 2a and the cable end 2b.

[0054] Signal contact pads P1a and P1b (collectively referred to as signal contact pads P1) and ground contact pad P2 are formed at cable ends 2a and 2b of FPC2. The signal contact pads P1 and ground contact pads P2 can be arranged along the width direction of FPC2 in a unit arrangement PU formed by a pair of signal contact pads P1a and P1b sandwiched between two ground contact pads P2. Furthermore, the signal contact pads P1a and P1b are formed on the same layer as and connected to the signal lines 25a and 25b of the differential signal line 25, respectively. The signal contact pads P1a and P1b have areas that are not covered by the first cover film 53 (described later) for contact with the signal contact terminal. The ground contact pad P2 is formed on the same layer as and connected to the ground wire 26. The ground contact pad P2 also has areas that are not covered by the first cover film 53 (described later) for contact with the ground contact terminal. It is also possible to regard the signal contact pad as the exposed part of the signal line and the ground contact pad as the exposed part of the ground line.

[0055] In several cases, a ground wire 26 is provided between adjacent differential signal lines 25 in the width direction of FPC2. The adjacent differential signal lines 25 in the width direction of FPC2 are electromagnetically coupled to the common ground wire 26 formed between them. Similarly, a ground contact pad P2 is provided between a pair of adjacent signal contact pads P1a and P1b in the width direction of FPC2. The pair of adjacent signal contact pads P1a and P1b in the width direction of FPC2 are electromagnetically coupled to the common ground contact pad P2 formed between them. In the above cases, the ground wire 26 and / or the ground contact pad P2 can be formed to be wide, thereby facilitating the formation of the through electrode described later in a more cost-effective manner.

[0056] According to Figure 6 As explicitly stated, the FPC2 comprises: a dielectric layer 50 with a thickness determined by a first surface 50p and a second surface 50q; a first wiring layer 51 formed on the first surface 50p of the dielectric layer 50; a second wiring layer 52 formed on the second surface 50q of the dielectric layer 50; a first cover film 53 laminated on the first surface 50p of the dielectric layer 50 via the first wiring layer 51; a second cover film 54 laminated on the second surface 50q of the dielectric layer 50 via the second wiring layer 52; and a reinforcing plate 55. Furthermore, the reinforcing plate 55 is provided for assembly with the adapter 3 and is not formed along the entire length of the FPC2.

[0057] The dielectric layer 50 is composed of a material having a prescribed relative dielectric constant, for example, a liquid crystal polymer. The first wiring layer 51 can be a wiring layer formed by patterning a metal foil. The differential signal line 25 and the ground line 26 described above are formed in the first wiring layer 51. The second wiring layer 52 can be a wiring layer formed by patterning a metal foil. One or more ground layers 27 electrically connected to the ground contact pad P2 via the first through electrode 28 (also referred to as a bump) that penetrates the dielectric layer 50 are formed in the second wiring layer 52.

[0058] As shown in Figs. 6 and 7, the ground layer 27 is formed as a full-area layer covering the entire area of the second wiring layer 52 except directly below the signal contact pad PI. Figure 5 Figure 6 As shown in Figs. 6 and 7, the ground layer 27 is formed as a full-area layer covering the entire area of the second wiring layer 52 except directly below the signal contact pad PI.

[0059] As shown in Figs. 6 and 7, the ground layer 27 is formed as a full-area layer covering the entire area of the second wiring layer 52 except directly below the signal contact pad PI. Figure 5 Figure 6 As shown in Figs. 6 and 7, the ground layer 27 is formed as a full-area layer covering the entire area of the second wiring layer 52 except directly below the signal contact pad PI.

[0060] The plurality of second through electrodes 29 that penetrate the dielectric layer 50 for electrically connecting the ground line 26 to the ground layer 27 can be arranged in the same column (or on the same straight line) as the first through electrode 28 at prescribed intervals in the longitudinal direction of the FPC 2. As shown in Figs. 6 and 7, the second through electrodes 29 are arranged in the same column as the first through electrode 28 at prescribed intervals in the longitudinal direction of the FPC 2. Figure 5 As is clear, the interval of the first through electrode 28 and the second through electrode 29 directly adjacent thereto can be different (for example, smaller) from the prescribed interval of the second through electrode 29. Thereby, as described later, the desired alignment of the first through electrode 28 and the ground contact terminal 46 can be facilitated. The first through electrode 28 is allocated with respect to the ground contact pad P2, whereby the generation of fluctuations can be suppressed as described later regardless of the pitch of the second through electrode 29.

[0061] As shown in Figs. 6 and 7, the ground layer 27 is formed as a full-area layer covering the entire area of the second wiring layer 52 except directly below the signal contact pad PI. Figure 7 Figure 8 ​​​Further to the connector 4, a plurality of signal contact terminals 45 and a plurality of ground contact terminals 46 are supported by the insulator 41 (e.g., at constant or different arrangement pitches). Typically, the signal contact terminals 45 and the ground contact terminals 46 are provided so as to be able to contact the signal contact pads Pl and the ground contact pads P2 arranged on a single surface of the FPC 2 individually, but other arrangements are also possible. For high-frequency signal transmission, in several cases, a unit arrangement 6 in which two signal contact terminals 45a, 45b (collectively, the signal contact terminals 45) are sandwiched between two ground contact terminals 46 is arranged in the width direction of the connector 4.

[0062] With the connector 4, the contact terminals 42 can have constant or different (e.g., two or more) arrangement pitches. In the former case, in the arrangement of the contact terminals 42, all of the contact terminals 42 (all of the signal contact terminals 45 and the ground contact terminals 46) are arranged at constant pitches (in the case of Figure 10 , Dl = El = Fl is satisfied). In the latter case, the pitch between directly adjacent signal contact terminals (Fl in the case of Figure 10 ), the pitch between directly adjacent ground contact terminals (Dl in the case of Figure 10 ), and the pitch between directly adjacent signal contact terminals and ground contact terminals are set to be different. Further, the pitch is defined as the interval of the center lines of the respective contact terminals 42 in the arrangement direction of the contact terminals 42 (typically, equal to the width direction of the connector 4) (further, the center lines exist in a plane orthogonal to the arrangement direction).

[0063] The contact terminals 42 (the signal contact terminals 45 and the ground contact terminals 46) are typically metal plates that are bent at one or more positions, are supported in a cantilevered manner by the insulator 41 of the connector 4, and are able to elastically displace (refer to Figure 9 ). When the connector 4 is not mechanically coupled to the adapter 3, the contact terminals 42 take an initial position. If the connector 4 is mechanically coupled to the adapter 3, the contact terminals 42 are pressed by the FPC 2 and displace.

[0064] The contact terminals 42 can have an arm portion that is bent so as to partially abut against the contact pads with the contact portions (refer to Figure 9 ). In detail, the signal contact terminals 45 can have an arm portion that is bent so as to partially abut against the signal contact pads Pl with the contact portions. Likewise, the ground contact terminals 46 can have an arm portion that is bent so as to partially abut against the ground contact pads P2 with the contact portions b3.

[0065] More specifically, the contact terminal 42 may have a fixing portion 42a fixed to the insulator 41, an arm portion 42b extending from the fixing portion 42a toward an opening in the insertion space 44 of the insulator 41, and a connecting portion 42c electrically connected to a contact (not shown) on the substrate 9 (e.g., by reflow soldering). The arm portion 42b has a bent shape to form a contact portion b3 between the fixing portion 42a and the free end of the arm portion 42b, which abuts against the signal contact pad P1 or the ground contact pad P2. In detail, the arm portion 42b has a first inclined portion b1 and a second inclined portion b2, and the contact portion b3 is formed between them. The first inclined portion b1 is inclined and extends from the fixing portion 42a. The second inclined portion b2 is a short post that is inclined and extends to a side opposite to the inclined direction of the first inclined portion b1. Thus, the contact portion b3 is formed in a convex shape between the first inclined portion b1 and the second inclined portion b2. The free end of arm 42b is located at one end of the second inclined portion b2 on the opposite side of the contact portion b3.

[0066] In this embodiment, when the FPC2 is electrically connected to the connector 4, the contact portion b3 of the arm portion 42b of the ground contact terminal 46 is positioned at least partially in contact with the surface of the cover portion 58 of the ground contact pad P2 covering the first through electrode 28 directly above it, or is positioned near the outer periphery of the cover portion 58 in contact with the ground contact pad P2 (see reference). Figure 10 Therefore, it is possible to improve the transmission characteristics of high-frequency signals (e.g., refer to...). Figures 11 to 14 When contact portion b3 is located near the outer periphery of cover portion 58, the distance between contact portion b3 and the outer periphery of cover portion 58 (e.g., minimum distance) is a distance that improves high-frequency signal transmission characteristics; specifically, it is a distance that reduces fluctuations related to return loss and / or insertion loss in the 20-25 GHz high-frequency band. Furthermore, the cover portion 58 of the aforementioned ground contact pad P2, except... Figure 10 external Figure 6 The diagram also shows the cover portion 58. The cover portion 58 is part of the ground contact pad P2, and therefore, the outer periphery of the cover portion 58 is equal to or in contrast to the illusory surface (typically a cylindrical surface) that determines the extent of the cover portion 58.

[0067] When FPC2 is electrically connected to connector 4, the first through electrode 28 can be positioned offset from the free end of arm 42b relative to the contact portion b3 of arm 42b. In this case, it is expected to further promote the reduction of fluctuations related to return loss and / or insertion loss.

[0068] Narrowing of the contact terminals 42 can contribute to the achievement of the above-mentioned object. In several cases, the arrangement pitch is in the range of 0.4 mm to 1.0 mm, and more preferably in the range of 0.5 mm to 0.8 mm. In addition, the gap between the contact portion and the outer periphery of the cover portion can be any value exceeding 0 mm and 0.4 mm or less. Even a slight distance can become a line for high-frequency signals, but a distance of 0.4 mm or less is formed, whereby the same improvement in high-frequency signal transmission characteristics can be observed. As an addition to or a substitute for the narrowing of the contact terminals 42, it is also possible to contribute to the formation of the first through-electrode 28 into a wide width or an enlarged diameter (in addition, a cheap through-electrode formation method can also be used at the same time).

[0069] When the contact portion b3 of the arm portion 42b is positioned at a position abutting on the outer periphery of the cover portion 58 of the ground contact pad P2, it is assumed that the contact portion b3 does not contact the outer periphery of the cover portion 58, but a slight gap is formed between the contact portion b3 and the outer periphery of the cover portion 58. The size of the gap allowed between the contact portion b3 and the outer periphery of the cover portion 58 is preferably any value exceeding 0 mm and 0.4 mm or less. In addition, it is also assumed that there is a deviation in the position of the contact portion of the ground contact terminal 46 from the cover portion 58 due to the influence of manufacturing errors and the like. For example, the contact portion of a certain ground contact terminal 46 can be positioned in abutment with the cover portion 58, the contact portion of the other ground contact terminal 46 can be in contact with the outer periphery of the cover portion 58, and the contact portion of the other ground contact terminal 46 can be spaced apart from the outer periphery of the cover portion 58 by a slight gap.

[0070] The arm portion 42b of the ground contact terminal 46 can extend in a tangential direction with respect to the outer periphery of the cover portion 58 of the ground contact pad P2 covering the first through-electrode 28 directly above the first through-electrode 28 when the FPC 2 is electrically connected to the connector 4 (see FIG. 6). Figure 10 Typically, the extending direction of the arm portion 42b is equal to the insertion direction of the FPC 2 with respect to the connector 4 or the long side direction of the FPC 2.

[0071] The two adjacent ground contact terminals 46 included in the unit arrangement 6 adjacent in the width direction of the connector 4 are each positioned in abutment at least partially with the surface of at least one common cover portion 58, or in abutment with the ground contact pad P2 in the vicinity of the outer periphery of the at least one common cover portion 58 (see FIG. 6). Figure 10In other words, in the adjacent pairs of GSSG arrangements of contact terminals 42, a pair of ground contact terminals 46 directly adjacent to each other (i.e., the central GG of a pair of "GSSGGSSG") are positioned relative to the common cover portion 58 (or, the common first through electrode 28) as described above. Thus, the high-frequency signal transmission characteristics can be improved by using a smaller number of first through electrodes 28, for example, promoting the adoption of inexpensive through electrode forming methods. Furthermore, preferably, for electrical connection with the ground layer 27, one first through electrode 28 is assigned relative to a ground contact pad P2.

[0072] The first through electrode 28 and the second through electrode 29 are arranged in the same column (or on the same straight line) along the long side of the FPC2. Furthermore, the contact portion b3 of the ground contact terminal 46 is not positioned directly above the first through electrode 28 (and the covering portion 58 of the ground contact pad P2). The first through electrode 28 can be easily formed at the center of the width of the ground contact pad P2, and the second through electrode 29 can be formed at the center of the width of the ground line 26. This allows for more accurate positioning of the through electrodes relative to the width of the FPC2, enabling the FPC2 to be manufactured in a more cost-effective manner.

[0073] When the first through electrode 28 has a cylindrical or frustum-shaped shape, the cover portion 58 has a circular outer periphery, and the arm portion 42b can extend along the tangential direction of its outer periphery. The first through electrode 28 can also be formed with a polygonal outer periphery such as a triangle, quadrilateral, or pentagon.

[0074] like Figure 10 As shown, the signal contact pads P1a and P1b can have a width variation portion 61 whose pad width is displaced as it extends along the long side direction of FPC2. The width variation portion 61 is provided between the narrow portion 62 and the wide portion 63, and its pad width changes continuously between them.

[0075] exist Figures 11 to 14 In the simulation results shown, the solid line represents Figures 1 to 10 The high-frequency signal transmission characteristics of the illustrated embodiment are represented by dashed lines. Figure 10 The high-frequency signal transmission characteristics of the comparative example without the first through electrode 28 are shown. Figure 11 As shown, return loss is improved. Figure 12 As shown, this improves insertion loss. Figure 13 As shown, near-end crosstalk is improved. Figure 14 As shown, front-end crosstalk is improved. Specifically, as according to... Figures 11 to 14 As explicitly stated, in the embodiments, fluctuations were suppressed in the vicinity of 20–25 GHz.

[0076] The FPC 2 can be manufactured by a bump build-up method. In the bump build-up method, a plurality of bumps are formed on the first face of the first copper foil, and a dielectric layer (e.g., liquid crystal polymer) and a second metal foil are sequentially stacked on the first face of the first metal foil on which the bumps are formed. Thereafter, the first metal foil, the dielectric layer, and the second metal foil are made to adhere to each other by heat pressing. In this stack, the first metal foil and the second metal foil are electrically connected via the through electrodes formed by the bumps. One of the first metal foil and the second metal foil is used as the first wiring layer 51, and the other is used as the second wiring layer 52. By pattern formation (e.g., selective etching) of the metal foils, a signal line, a ground line, a ground layer, and a contact pad can be formed. As the metal foils, a copper foil can be used. For the FPC 2, other manufacturing methods can also be employed.

[0077] The insulator 41 of the connector 4 can be manufactured from a plastic material using an injection molding device. The contact terminal 42 can be manufactured by processing (punching processing, bending processing) of a metal plate. The contact terminal 42 can be mounted and supported with respect to the insulator 41 by a method such as insert molding, press-in, adhesion, or the like.

[0078] In the Figure 10 , one ground line 26 is formed between the differential signal lines 25, and one ground contact pad P2 is provided between the pair of signal contact pads Pla, Plb, but this is not limiting. As shown in Figure 15 , two ground lines 26 can be formed between the differential signal lines 25, and two ground contact pads P2 can be provided between the pair of signal contact pads Pla, Plb. In other words, one ground contact pad P2 (or ground line 26) can be allocated with respect to one ground contact terminal 46.

[0079] In the Figure 10 , the arm portion 42b of the ground contact terminal 46 extends in a tangential direction with respect to the outer periphery of the cover portion 58 in a manner not to overlap the cover portion 58, but this is not limiting. As shown in Figure 15 , the arm portion 42b of the ground contact terminal 46 can extend in a tangential direction with respect to the outer periphery of the cover portion 58 in a manner to overlap a portion of the cover portion 58. Further, in the Figure 10 , the arm portion 42b and the contact portion b3 are not disposed directly above the first through electrode 28. In the Figure 15 , the arm portion 42b and the contact portion b3 are partially disposed directly above the first through electrode 28. The arm portion 42b of the ground contact terminal 46 can be formed to have a wider width, whereby the arm portion 42b can also overlap the entire cover portion 58 directly above the first through electrode 28.

[0080] In the Figure 16In the illustrated manner, the transmission line 7 is configured as a combination of a differential coplanar line and a microstrip line, and the ground layer 27 can be formed so as to oppose the transmission line 7 except for directly below the contact pad Pl. Typically, a plurality of ground layers 27 are formed in the second wiring layer 52, the number of which is equal to the number of the transmission lines 7. The ground lines 26 corresponding to the respective transmission lines and the ground contact pads P2 and the ground layers 27 are electrically connected, whereby the ground potential can be divided or made non-common between the transmission lines 7 of the FPC 2, and thus the high-frequency signal transmission characteristics (e.g., crosstalk reduction) can be improved. Also in this manner, the alignment of the first through-electrode 28 and the ground contact terminal 46 is set as described above, whereby the same effects as described above can be expected.

[0081] In view of the above teachings, various modifications can be made to each of the embodiments and each of the features by those skilled in the art. The wiring substrate need not be flexible, and should not be limited to a flexible cable. For example, the various features disclosed herein can be applied to a wiring substrate of a card edge connector. The number of ground contact terminals provided between the pair of signal contact terminals for differential signal transmission is not limited to two, but can be one. Even if the adapter is omitted from the connector, the same effects can be expected.

[0082] Symbol explanation:

[0083] 1: high-frequency signal transmission device; 2: FPC; 2a: cable end; 2b: cable end; 3: adapter; 4: connector; 25: differential signal line; 25a: signal line; 25b: signal line; 26: ground line; 27: ground layer; 28: first through-electrode; 29: second through-electrode; 41: insulator; 42: contact terminal; 45: signal contact terminal; 46: ground contact terminal; b3: contact portion; 50: dielectric layer; 58: cover portion; Pl: signal contact pad; P2: ground contact pad.

Claims

1. A high frequency signal transmission device, characterized by comprising: Possessing: a connector configured to support a contact terminal group by an insulator, the contact terminal group being regularly arranged by a plurality of contact terminals including a plurality of signal contact terminals and a plurality of ground contact terminals; and a wiring substrate configured to form a plurality of signal contact pads, a plurality of ground contact pads, and one or more ground layers at one cable end, the one or more ground layers being electrically connected to the ground contact pads via at least one first through electrode that penetrates a dielectric layer of the wiring substrate, the ground contact terminal has an arm portion that is bent so as to partially abut against the ground contact pad with a contact portion, the contact portion of the arm portion is positioned to at least partially abut against a surface of a covering portion of the ground contact pad that covers the first through electrode directly above the first through electrode when the wiring substrate is electrically connected to the connector, the contact terminal group includes a plurality of unit arrangements, each unit arrangement being composed of a total of four contact terminals in which two signal contact terminals are sandwiched by two ground contact terminals, two adjacent ground contact terminals included in the unit arrangements adjacent in the width direction of the connector are respectively positioned to at least partially abut against a surface of at least one common covering portion.

2. The high-frequency signal transmission device according to claim 1, wherein: a fluctuation in return loss and / or insertion loss in a high-frequency band is reduced.

3. The high-frequency signal transmission device according to claim 1, wherein: the first through electrode is positioned to be biased in a direction away from a free end of the arm portion compared to the contact portion of the arm portion when the wiring substrate is electrically connected to the connector.

4. The high-frequency signal transmission device according to claim 1, wherein: a plurality of second through electrodes are arranged in the same row as the first through electrode at a prescribed interval along the long side direction of the wiring substrate, the plurality of second through electrodes penetrating the dielectric layer in order to electrically connect a ground line formed in the same layer as the ground contact pad to the ground layer, an interval between the first through electrode and the second through electrode directly adjacent thereto is different from the prescribed interval of the plurality of second through electrodes.

5. The high-frequency signal transmission device according to claim 1, wherein: the first through electrode has a cylindrical or conical frustum shape, and the arm portion extends in a tangential direction of an outer periphery of the covering portion.

6. The high-frequency signal transmission device according to claim 1, wherein: the plurality of signal contact pads and ground contact pads are arranged in the width direction of the wiring substrate in a manner in which one pair of signal contact pads is sandwiched by two ground contact pads, and one ground contact pad is provided between a pair of signal contact pads adjacent in the width direction of the wiring substrate.

7. The high-frequency signal transmission device according to claim 1, wherein: The wiring substrate has a plurality of differential signal lines each composed of two signal lines, and a plurality of ground lines formed on both sides of each differential signal line in a manner of sandwiching each differential signal line in a width direction of the wiring substrate, one ground line being provided between the differential signal lines adjacent in the width direction of the wiring substrate.

8. The high-frequency signal transmission device according to claim 1, wherein One of the first through electrodes is assigned with respect to one of the ground contact pads for electrical connection with the ground layer.

9. The high-frequency signal transmission device according to claim 1, wherein The one or more ground layers include a plurality of ground layers each extending along a long side direction of the wiring substrate, and the plurality of ground contact pads are individually electrically connected with the plurality of ground layers via the first through electrodes.

10. The high-frequency signal transmission device according to claim 9, wherein The wiring substrate further includes a plurality of ground lines formed in the same layer as the plurality of ground contact pads, each of the plurality of ground lines being electrically connected with each of the plurality of ground layers via a plurality of second through electrodes that penetrate the dielectric layer.

11. The high-frequency signal transmission device according to claim 1, further comprising an adapter that supports the cable end of the wiring substrate and is mechanically coupled with the connector, the cable end being positioned at a predetermined position in the connector by the mechanical coupling of the connector with the adapter.

12. A method of electrically connecting a wiring substrate with a connector configured to support a contact terminal group through an insulator, the contact terminal group being regularly arranged by a plurality of contact terminals including a plurality of signal contact terminals and a plurality of ground contact terminals, The method of electrically connecting a wiring substrate with a connector according to claim 12, wherein A plurality of signal contact pads, a plurality of ground contact pads, and one or more ground layers are formed at a cable end of at least one of the wiring substrates, the one or more ground layers being electrically connected with the ground contact pads via at least one first through electrode that penetrates a dielectric layer, The method includes a process of positioning a contact portion of the ground contact terminal at a position at least partially abutting a surface of a covering portion of the ground contact pad that covers directly above the first through electrode, The contact terminal group includes a plurality of unit arrangements each composed of a total of four contact terminals in which two of the signal contact terminals are sandwiched by two of the ground contact terminals, Two adjacent ground contact terminals included in the unit arrangements adjacent in a width direction of the connector are respectively positioned at positions at least partially abutting a surface of at least one common covering portion. ​

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