Abstract:
A structure of signal transmission line has a core portion, a middle material layer and a coating layer. The core portion includes at least one transmission medium enveloped with an insulation layer. The coating layer includes at least one layer. The middle material layer is provided between the core portion and the coating layer, and has at least a metallic-wire knitting layer and a paper wrapping layer.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a structure of signal transmission line, especially to a structure of signal transmission line able to transmit signals fast, having lower radio frequency and magnetic field interference, less static electricity, lower attenuation rate and smaller distortion. It is suitable particularly for use in signal transmission lines such as those for speakers, guitar wires, microphones etc. 
     2. Description of the Prior Art 
     In conventional signal lines, conductors for transmitting signals generally are divided into the kinds of single conductors and conductors with multiple mutually entangled cores. A single conductor, for example, such as the structure of coaxial cable shown in FIG. 1, is characterized by: the insulation layer enveloping a conductor  1  is formed as a coaxial cable by combining with a cylinder member  2  made by press shaping of PE, a Mylar tape  3  made from aluminum foil, an obscuring layer  4  made by knitting copper lines and a PVC enveloping member  5 . 
     The coaxial cable is a round PE pipe made by press shaping, in order to lower its electric capacity and attenuation rate. However, the effect of insulation of PE is not the best, and the obscuring layer is not able to make 100% obscuring, it is still a problem to be solved that the degree of mutual interference among a magnetic field, radio frequencies and static electricity is still quite high, and refraction or reflection of transmitted signals can be induced during transmission. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a structure of signal transmission line to separately transmit signals of high and low frequencies to lower the skin effect. 
     The secondary object of the present invention is to provide a structure of signal transmission line able to transmit signals fast, having lower attenuation rate, smaller distortion and superior quality. 
     Another object of the present invention is to provide a structure of signal transmission line having the effect of reducing static electricity and lowering radio frequency and magnetic field interference. 
     To achieve the above stated objects, the present invention is comprised of a core portion, a middle material layer and a coating layer. The present invention is characterized by that: the core portion includes at least one transmission medium enveloped with an insulation layer; the coating layer includes at least one layer; the middle material layer is provided between the core portion and the coating layer, and is comprised of at least a metallic-wire knitting layer and a paper wrapping layer. By separated transmitting of signals of high and low frequencies with the core portion when the latter is a conductor unit with plural cores (transmission media), the skin effect is lowered; and by providing more than one obscuring layers, the degree of mutual interference among a magnetic field, radio frequencies and static electricity can be lowered, and thereby, transmission with lower attenuation rate, smaller distortion and superior quality can be obtained. 
     The present invention will be apparent after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the structure of a conventional signal transmission line; 
     FIG. 2 is an analytical perspective view showing the structure of the first embodiment of the present invention; 
     FIG. 3 is an analytical perspective view showing the structure of the second embodiment of the present invention; 
     FIG. 4 is an analytical perspective view showing the structure of the third embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring firstly to FIG. 2, in the first preferred embodiment of the present invention, a guitar wire is shown in a perspective view, a core  20  is formed by coating an insulation PE layer  22  over a conductor  21  made of pure silver, the insulation PE layer  22  is covered thereover with a conductor  23  made of pure copper of single crystal in single direction coated with lacquer, and a PE foam layer  24  further covers the insulation PE layer  22  to make the two conductors be insulated from each other. The PE foam layer  24  then is enveloped sequentially with a PVC conductive layer  41 , a knitted layer  42  plated with silver and a paper wrapping layer  43  to form a middle material layer  40 . Finally, the middle material layer  40  is enveloped with a first coating layer  30  and the second coating layer  31  made of polyvinyl chloride to complete the structure of the signal transmission line of the present invention. 
     As shown in FIG. 3 which shows the structure of the second preferred embodiment, namely a visual signal transmission line, of the present invention, wherein, a core  20  is formed by coating an insulation PE layer  22  over a conductor  21  made of pure silver, the insulation PE layer  22  is covered thereover with a conductor  23  made of pure copper of single crystal in single direction coated with lacquer, and a PE foam layer  24  further covers the insulation PE layer  22  to make the two conductors be insulated from each other. The PE foam layer  24  then is enveloped sequentially with a PVC conductive layer  41 , a knitted layer  42  plated with silver, a foamed Teflon-tape (PTFE) wrapping layer  44  and another metallic-wire knitting layer  45  to form a middle material layer  40 . Finally, the middle material layer  40  is enveloped with a first coating layer  30  and the second coating layer  31  made of polyvinyl chloride to complete the structure of the signal transmission line of the present invention. 
     Referring to FIG. 4, in the third preferred embodiment of the present invention, a microphone wire is shown, a core portion is comprised of two cores (transmission media)  20  formed each by coating an insulation PE layer  22  over a conductor  21  made of pure silver, the insulation PE layer  22  is covered thereover with a conductor  23  made of pure copper of single crystal in single direction coated with lacquer, and a PE foam layer  24  further covers the insulation PE layer  22  to make the two conductors be insulated from each other. The two cores  20  then are enveloped sequentially with two PVC conductive layers  41 , a cotton yarn filled layer  46  (with this, the wire is softer and can be shaped more easier), a knitted layer  45  plated with silver and a paper wrapping layer  43  to form a middle material layer  40 . Finally, the middle material layer  40  is enveloped with a first coating layer  30  made of polyvinyl chloride to complete the structure of the signal transmission line of the present invention. 
     It can be known from the above embodiments that, the plural-core conductors of the core portion (the conductors made of pure silver and pure copper of single crystal in single direction coated with lacquer) are respectively insulated with an insulation PE layer  22  and an insulation PE foam layer  24 , in order that the two conductors are suitably separated from each other to separately transmit signals of high and low frequencies through the two conductors, so that the high and low frequencies are not interfered by each other to thereby lower the skin effect. And more, the middle material layer (including a PVC conductive layer, a knitted layer plated with silver and a PTFE layer) can have an effect of obscuring to thereby effectively prevent interference among a magnetic field, radio frequencies and static electricity, and the cotton yarn filled layer or the paper wrapping layer can increase the softness and easiness of shaping of a wire, and thereby attenuation rate of the wire can be reduced, distortion of the wire can be smaller, and quality of the wire can be better. 
     The cores of the plural-core conductor unit of the present invention are separately insulated, this can lower the skin effect, to render transmit signals of high and low frequencies to be transmitted separately without interfering with each other, the middle material layer can have an effect of obscuring to thereby lower interference among a magnetic field, radio frequencies and static electricity. This is innovative to wires of such kind available presently, and the effect in enhancing the functions thereof is evident.