Patent Publication Number: US-10777942-B2

Title: Signal transmission cable

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan Application Serial No. 107121581, filed on Jun. 22, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of the specification. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The disclosure relates to a signal transmission cable. 
     Description of the Related Art 
     Currently, a differential signal line has a first connecting part which is connecting with a mother board and a USB connector and a second connecting part which is connecting with the USB connector and a cable, and the first connecting part and the second connecting part jointly generate the common mode current on the surfaces of the USB connector and the cable due to impedance and grounding discontinuity of reference signals is excited, thereby causing the problem of common mode noise radiation interference at the frequency of 2.5 GHz. 
     BRIEF SUMMARY OF THE INVENTION 
     According to an aspect of the disclosure, a signal transmission cable is provided herein. The signal transmission cable comprises: a first connector; a signal line, electrically connected to the first connector; a first shielding line, electrically connected to the first connector, extending away from the first connector and wound around at least a portion of the signal line along a first rotating direction; and a second shielding line, electrically connected to the first connector, the second shielding line extends away from the first connector and winds around at least a portion of the signal line along a second rotating direction. 
     According to the above-mentioned structural configuration, because the first shielding line and the second shielding line of the disclosure are two spiral parts with opposite rotating directions and together form a double-spiral structure, the electromagnetic radiation generated by the common mode current flowing in the first shielding line and the second shielding line substantially eliminates each other. Therefore, the signal transmission cable of this embodiment reduces the electromagnetic wave interference caused by the common mode current generated on the shielding surface of the cable, thereby improving the sensitivity and signal throughput of a radio frequency component in an electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial three-dimensional view showing a signal transmission cable according to an embodiment of the disclosure; 
         FIG. 2A  is an exploded view showing the structure as shown in  FIG. 1 ; 
         FIG. 2B  is a cross-sectional view showing the structure as shown in  FIG. 1  along a line segment B-B; 
         FIG. 2C  and  FIG. 2D  are respectively schematic diagrams showing the relationship between the rotating direction and the extending direction of a shielding line in the structure as shown in  FIG. 1 ; and 
         FIG. 3  is a partial three-dimensional view showing a signal transmission cable according to another embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring to  FIG. 1 ,  FIG. 2A  and  FIG. 2B ,  FIG. 1  is a partial three-dimensional view showing a signal transmission cable  1  according to an embodiment of the disclosure,  FIG. 2A  is an exploded view showing the structure as shown in  FIG. 1 , and  FIG. 2B  is a cross-sectional view showing the structure as shown in  FIG. 1  along a line segment B-B. As shown in the figures, in this embodiment, the signal transmission cable  1  includes a first connector  10 , a signal line  12 , a first conductive component  11 , a second conductive component  13 , a first shielding line  14 , a second shielding line  16 , a shielding layer  18  (see  FIG. 2A  and  FIG. 2B ) and a protective layer  19 . In order to more clearly show the disclosure, the protective layer  19  in  FIG. 1  is shown by dotted lines, and the shielding layer  18  is omitted. 
     As shown in  FIG. 1 ,  FIG. 2A  and  FIG. 2B , the signal line  12  is electrically connected to the first connector  10 . The signal line  12  extends away from the first connector  10 . In some embodiments, the signal line  12  includes at least two circuits (omitted) as round-trip circuits for transmitting power or transmitting signals. In this embodiment, the influence caused by common mode signals is reduced by the configuration of the first shielding line  14  and the second shielding line  16 . 
     In this embodiment, the first conductive component  11  is electrically connected to the first connector  10  and wound around the signal line  12 . In this embodiment, the first conductive component  11  has a cylindrical shape and two openings  110 ,  112  opposite to each other, for being sleeved with the signal line  12 . The opening  110  of the first conductive component  11  faces toward the first connector  10 , and the opening  112  of the first conductive component  11  faces away from the first connector  10 . The signal line  12  extends away from the first connector  10  and passes through the opening  110  and the opening  112  of the first conductive component  11 . The common mode current generated by the signal line  12  flows through the first conductive component  11 . In some embodiments, the material of the first conductive component  11  includes aluminum (Al), copper (Cu) or any other suitable material. In some embodiments, the structure of the first conductive component  11  is woven by conductive lines. 
     In this embodiment, the second conductive component  13  is positioned at one side of the shielding layer  18  opposite to the first connector  10 , is separated from the shielding layer  18 , and wound around the signal line  12 . In this embodiment, the second conductive component  13  has a cylindrical shape and two openings  130 ,  132  opposite to each other, for being sleeved with the signal line  12 . The signal line  12  passes through the opening  130  and the opening  132  of the second conductive component  13 . The common mode current generated by the signal line  12  flows through the second conductive component  13 . In some embodiments, the material of the second conductive component  13  includes aluminum (Al), copper (Cu) or any other suitable material. In some embodiments, the structure of the second conductive component  13  is woven by conductive lines. 
     As shown in  FIG. 2A  and  FIG. 2B , the shielding layer  18  is positioned between the first shielding line  14  and the signal line  12 , wound around the signal line  12 , and separated from the first connector  10 , the first conductive component  11  and the second conductive component  13  (see  FIG. 2A ). In some embodiments, the material of the shielding layer  18  includes aluminum (Al), copper (Cu) or any other suitable material. In some embodiments, the structure of the shielding layer  18  is woven by conductive lines. 
     As shown in  FIG. 1  and  FIG. 2A , the first shielding line  14  is electrically connected to the first connector  10 , extending away from the first connector  10 , and wound around the signal line  12  along a first rotating direction R 1  (see  FIG. 2A ). In this embodiment, from the perspective as shown in  FIG. 2A , the first rotating direction R 1  is counterclockwise wound around the signal line  12  along an extending direction D. That is, the first shielding line  14  is wound around the signal line  12  in a spiral winding mode and covering the signal line  12 , to form a first spiral part H 1  (see  FIG. 2A ). 
     In some embodiments, the length of each of the winding distances of the first shielding line  14  wound around the signal line  12  is the same. In some other embodiments, the length of the winding distances of the first shielding line  14  wound around the signal line  12  is gradually changed. In an embodiment, the lengths of the winding distances of the first shielding line  14  wound around the signal line  12  is gradually increased as the first shielding line  14  extends away from the first connector  10 . As shown in  FIG. 2A , the portion of the first shielding line  14  close to the first connector  10  has a winding distance P 1 , the other portion of the first shielding line  14  away from the first connector  10  has a winding distance P 3 , and the winding distance P 3  is greater than the winding distance P 1 . Therefore, the portion of the signal transmission cable  1  close to the first connector  10  has a good anti-noise effect, and the other portion of the signal transmission cable  1  away from the first connector  10  has a better bending capability so as to enhance the convenience of usage of the signal transmission cable  1 . In some embodiments, the first shielding line  14  is tightly wound around the signal line  12  to completely cover the signal line  12 . Further, referring to  FIG. 2C ,  FIG. 2C  is a schematic diagram showing the relationship between the first rotating direction R 1  and the extending direction D of the first shielding line  14  in the structure as shown in  FIG. 1 . In this embodiment, a first angle G 1  formed between the first rotating direction R 1  of the first connector  10  and the extending direction D of the first shielding line  14  is within a scope between approximately 60 degrees and approximately 90 degrees. 
     Further, as shown in  FIG. 1  and  FIG. 2A , the first shielding line  14  is positioned between the signal line  12  (and the first conductive component  11  and the shielding layer  18 ) and the second shielding line  16 . One end of the first shielding line  14  is electrically connected to a connection point C 1  of the first conductive component  11  adjacent to the first connector  10 , and the other end of the first shielding line  14  is electrically connected to a connection point C 3  of the second conductive component  13 . In some embodiments, the first shielding line  14  is covered with an insulating material. In some embodiments, the material of the first shielding line  14  includes copper or any other suitable material. In some embodiments, the size of the first shielding line  14  is applied to different outer diameters of lines. In some embodiments, the first shielding line  14  of the signal transmission cable  1  is connected to the first connector  10  without the first conductive component  11 . 
     As shown in  FIG. 1  and  FIG. 2A , the second shielding line  16  is electrically connected to the first connector  10 , extending away from the first connector  10 , and wound around the signal line  12  along a second rotating direction R 2  (see  FIG. 2A ). In an embodiment, from the perspective as shown in  FIG. 2A , the second rotating direction R 2  is clockwise wound around the signal line  12  along the extending direction D, and is opposite to the first rotating direction R 1 . That is, the second shielding line  16  is wound around the signal line  12  covering the signal line  12  in a spiral winding mode, to form a second spiral part H 2  (see  FIG. 2A ). 
     In some embodiments, the lengths of the winding distances of the second shielding line  16  wound around the signal line  12  is the same. In some other embodiments, the lengths of the winding distances of the second shielding line  16  wound around the signal line  12  is gradually changed. In an embodiment, the lengths of the winding distances of the second shielding line  16  wound around the signal line  12  is gradually increased as the second shielding line  16  extends away from the first connector  10 . As shown in  FIG. 2A , the portion the second shielding line  16  close to the first connector  10  has a winding distance P 2 , the other portion of the second shielding line  16  away from the first connector  10  has a winding distance P 4 , and the winding distance P 4  is greater than the winding distance P 2 . Therefore, the portion of the signal transmission cable  1  close to the first connector  10  has a good anti-noise effect, and the other portion of the signal transmission cable  1  away from the first connector  10  has a better bending capability so as to enhance the convenience of the usage of the signal transmission cable  1 . In some other embodiments, the second shielding line  16  is tightly wound around the signal line  12  to completely cover the first shielding line  14 . Further, referring to  FIG. 2D ,  FIG. 2D  is a schematic diagram showing the relationship between the second rotating direction R 2  and the extending direction D of the second shielding line  16  in the structure as shown in  FIG. 1 . In this embodiment, a second angle G 2  formed between the second rotating direction R 2  of the first connector  10  and the extending direction D of the second shielding line  16  is within a scope between approximately 60 degrees and approximately 90 degrees. In this embodiment, the first shielding line  14  and the second shielding line  16  form a double-spiral structure H. 
     Further, as shown in  FIG. 1  and  FIG. 2A , the second shielding line  16  is positioned between the first shielding line  14  and the protective layer  19 . One end of the second shielding line  16  is electrically connected to a connection point C 2  (see  FIG. 2A , omitted in  FIG. 1  due to perspective) of the first conductive component  11  adjacent to the first connector  10 , and the other end of the second shielding line  16  is electrically connected to a connection point C 4  (see  FIG. 2A , omitted in  FIG. 1  due to perspective) of the second conductive component  13 . In this embodiment, the second shielding line  16  is electrically insulated from the first shielding line  14 . In an embodiment, the second shielding line  16  is covered with an insulating material. In this embodiment, the connection point C 2  of the second shielding line  16  is separated from the connection point C 1  of the first shielding line  14 . The connection point C 4  of the second shielding line  16  is separated from the connection point C 3  of the first shielding line  14 . In some embodiments, the material of the second shielding line  16  includes copper or any other suitable material. In some embodiments, the size of the second shielding line  16  is applied to different outer diameters of lines. 
     In this embodiment, the common mode current generated by the signal line  12  flows through the first shielding line  14  and the second shielding line  16  by the first conductive component  11  and/or the second conductive component  13 . Because the first shielding line  14  and the second shielding line  16  are two spiral parts with opposite rotating directions, the electromagnetic radiation generated by the common mode current on the first shielding line  14  and the second shielding line  16  substantially eliminates each other so as to inhibit the common mode noise (CM noise) radiation caused by the common mode current. Therefore, the signal transmission cable  1  of this embodiment reduces the influence of the electromagnetic radiation caused by the common mode current on the electronic device so as to maintain the performance (sensitivity and throughput) of the RF component in the device. 
     In an embodiment, the signal transmission cable  1  supports USB3.0. Further, in a test of receiving sensitivity, based on the frequency use scope of some signal transmission cables  1 , compared with a signal transmission cable without a double-spiral structure H (see  FIG. 2A ), the receiving sensitivity of the signal transmission cable  1  is improved by at least 10 dB. 
     As shown in  FIG. 1 ,  FIG. 2A  and  FIG. 2B , the protective layer  19  is covering the second shielding line  16  and is insulated from the first connector  10 , the shielding layer  18 , the first shielding line  14 , and the second shielding line  16 . In an embodiment, the second shielding line  16  is covered in the insulating material, and the protective layer  19  covers the second shielding line  16  and contacts the insulating material so as to be insulated from the second shielding line  16 . In this embodiment, the protective layer  19  in the signal transmission cable  1  is floating so as to shield the interference of the electromagnetic radiation on the signal transmission cable  1  in the external environment. In some embodiments, the material of the protective layer  19  is a conductive material. In an embodiment, the material of the protective layer  19  includes aluminum, copper or any other suitable material. 
     Referring to  FIG. 3 ,  FIG. 3  is a partial three-dimensional view showing a signal transmission cable  2  according to another embodiment of the disclosure. As shown in  FIG. 3 , in this embodiment, the signal transmission cable  2  includes a first connector  10 , a second connector  20 , a first conductive component  11 , a second conductive component  13 , a signal line  12 , a shielding layer (referring to same component in  FIG. 2A ), a first shielding line  24 , a second shielding line  26  and a protective layer  19 . In order to more clearly show the disclosure, the protective layer  19  in  FIG. 3  is shown by dotted lines, and the shielding layer is omitted. 
     It should be noted that the difference between this embodiment and the embodiments as shown in  FIG. 1  to  FIG. 2B  is that this embodiment further includes the second connector  20 . The signal line  12  is electrically connected between the first connector  10  and the second connector  20 . Further, the second conductive component  13  is electrically connected to the second connector  20  and is wound around the signal line  12 . In addition, compared to the signal transmission cable  1  as shown in  FIG. 1 , the first shielding line  24 , the second shielding line  26  and the shielding layer extend from the first connector  10  to the second conductive component  13 . And, the first shielding line  24 , the second shielding line  26  and the shielding layer are connected to the second connector  20  through the second conductive component  13 . In this embodiment, the first shielding line  24  and the second shielding line  26  form a double-spiral structure H′. 
     Because the first shielding line  24  and the second shielding line  26  are two spiral parts with opposite rotating directions of the double-spiral structure H′, the electromagnetic radiation generated by the common mode current flowing in the first shielding line  24  and the second shielding line  26  substantially eliminates each other so as to inhibit the CM noise between the first connector  10  and the second connector  20  due to the common mode current. 
     The detailed descriptions of the specific embodiments of the disclosure obviously show that because the first shielding line and the second shielding line of the disclosure are two spiral parts with opposite rotating directions and jointly form the double-spiral structure, the electromagnetic radiation generated by the common mode current flowing in the first shielding line and the second shielding line substantially eliminates each other so as to inhibit the CM noise caused by the common mode current. Therefore, the signal transmission cable of this embodiment reduces the influence of the electromagnetic radiation caused by the common mode current on the electronic device. 
     The features of the foregoing embodiments provide those of ordinary skill in the art with a better understanding of the aspects of the disclosure. It will be appreciated by those of ordinary skill in the art that to achieve the same objectives and/or the advantages of the embodiments described herein, other processes and structures may be further designed or modified readily based on the disclosure. It will be appreciated by those of ordinary skill in the art that such equivalent structures do not depart from the spirit and scope of the disclosure, and various changes, replacements, and modifications may be made without departing from the spirit and scope of the disclosure.