JP2008078105A - Cable for audio - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cable for an audio, capable of eliminating tone quality degrading factors due to various kinds of cables applied to an audio system. <P>SOLUTION: A chassis has metal foils 12 having a thickness of 15 μm or less stuck to an insulation tape 11 on which adhesive 10 is applied. Leading terminals are joined to both ends of the chassis while being connected to the metal foils 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an audio cable.

  In audio equipment, wiring cables are used in the housing of each audio device, and various connection cables are used to connect the devices and play sound. The characteristics of these cables affect the playback sound quality. Therefore, various cables have been provided to prevent deterioration of sound quality. Products conventionally provided as audio cables are based on a single core wire that transmits a signal with a single electric wire, and uses a number of bare thin wires to compensate for the shortcomings of a single core wire. It can be broadly divided into those using a core wire and those using a litz wire that uses an insulated wire instead of a bare wire, and cables using a combination of these methods are also used.

Among the above-mentioned audio cables, the single-core cable has a smaller surface area than the multi-core cable having the same total cross-sectional area, and the skin effect (the current flows on the conductor surface as the frequency of the alternating current increases, and There is a problem that the influence of the phase changing action) is increased, the signal transmission state at each frequency is different, and the thick line is not flexible and is not practical.
In the case of a bare multifilamentary wire, although the effect of the skin effect is reduced, there is a problem that a so-called stray current is generated in which signals jump between the wires due to the strand jump phenomenon, and the signal is disturbed. In the case of using litz wires, stray currents are not generated because insulated wires are used, but proximity effects between the wires (if there are conductors close to each other, alternating current flowing in each conductor generates magnetic fields. Therefore, the transmission state of the signal at each frequency is different in the same manner as the skin effect. Further, in the audio cable, more or less mechanical vibration is generated when a signal current flows, which also causes deterioration in sound quality.

  It is thought that the playback sound quality is a problem in audio cables because the transmission path of the signal propagating in the cable is not constant and becomes a complicated path, and further, the mechanical vibration of the cable due to the signal current However, it is considered that this may cause blurring of sound during audio playback or cause unstable sound image localization. The present invention has been made to solve the problems associated with these conventional audio cables, and an audio cable capable of improving sound quality by eliminating sound bleeding and instability of sound image localization during audio playback. The purpose is to provide.

  The present invention has the following configuration in order to achieve the above object. That is, a main body in which one or more metal foils having a thickness of 15 μm or less are applied in parallel to each other with a predetermined interval on an insulating tape coated with an adhesive, and both ends of each row of the metal foils. A lead-out terminal is joined by being electrically connected to the metal foil. In addition, the width | variety, length, row | line number of metal foil which form a conductor part, and the space | interval between each metal foil can be suitably selected by a use. The reason why the metal foil of 15 μm or less is used is that the skin effect and proximity effect at the audio frequency are almost negligible. As the metal foil becomes thicker, the skin effect and proximity effect become larger and the above object cannot be achieved. Moreover, the adhesive is used as the adhesive material for the insulating tape and the metal foil in order to maintain the flexibility and flexibility necessary for the cable and to suppress the foil vibration of the metal foil. Is not suitable. Furthermore, the insulating tape requires flexibility and flexibility, but a material having a large elongation rate is not preferable in terms of work.

  A plurality of the main bodies are laminated and pasted, and the lead terminals are joined to the metal foils of all layers in each row. Thus, by laminating a plurality of the main bodies, the current capacity required by the cable can be ensured.

  Further, a plurality of the cables manufactured as described above are pasted together with an adhesive insulator made of an electrical insulator interposed therebetween to form a large number of conductor paths. At this time, since the thickness of the adhesive insulator becomes a factor for determining the interlayer capacitance of each conductor path, the thickness is determined according to the application.

  Further, in the cable manufactured above, a metal foil of 15 μm or less is pasted on the entire outer periphery with an adhesive insulator made of an electrically insulating material in the main body, and the lead terminal is a coaxial cable. The core wire portion is characterized in that the shield wire portion is joined to the outer peripheral metal foil. This is mainly a cable that allows a minute current to flow, and has a shielding effect. In this case as well, the thickness of the adhesive insulator is a factor that determines the characteristic impedance of the cable, so the thickness is determined according to the application. .

  According to the audio cable according to the present invention, by forming a metal foil having a thickness of 15 μm or less as the conductor portion, it is possible to suppress the skin effect and the proximity effect that occur when the audio signal propagates through the conductor portion. Since the conductor portion is formed via the insulating tape, it is possible to effectively improve the reproduction sound quality without a signal jumping between the conductors. Adhesives and adhesive insulators are used as the adhesive material, so that the necessary flexibility and flexibility for cables are not lost, and the mechanical vibrations of adhesives and adhesive insulators are lost. The absorption effect absorbs the vibration of the foil that occurs when a current flows through the metal foil, and a further improvement in sound quality can be achieved.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(First embodiment)

  FIG. 1 is a perspective view showing a first embodiment of an audio cable according to the present invention, FIG. 2 is a cross-sectional view of the A surface of this embodiment, and FIG. 3 is a perspective view showing the structure of the main body. 4 is a partially developed perspective view showing a joined state of the lead terminals.

  As shown in FIGS. 2 and 3, the audio cable 1 includes a main body 01 attached to the insulating tape 11 a to which the adhesive 10 is applied so that the metal foils 12 a and 12 b do not overlap each other. As shown in FIG. 4, the metal foils 12 a and 12 b are formed by lead terminals 13 a, 13 b, 13 c, and 14 d joined to both ends by soldering or the like. In this embodiment, two rows of metal foil are used, but the number of rows is not limited.

  In the present embodiment, acetate cloth having a thickness of 23 μm and a width of 25 mm is used as the insulating tape 11 to which the adhesive 10 is applied. The insulating tape 11 to which the pressure-sensitive adhesive 10 is applied has a wide variety of tapes such as cloth, paper, plastic, etc. as its base material. However, as an adoption standard, it has excellent electrical insulation and flexibility. In addition, the condition is that the elongation is small. In particular, when an insulating tape having a large elongation is pulled during the manufacturing process or in the state of a product, there is a high risk of the attached metal foil being cut. Therefore, it is necessary to increase the thickness to suppress the elongation.

  The pressure-sensitive adhesive 10 applied to the insulating tape 11 includes rubber-based, acrylic-based, silicon-based, and the like. Any pressure-sensitive adhesive is suitable for the present invention, but in this embodiment, a rubber-based rubber having excellent vibration absorption. An adhesive was used.

  In the present embodiment, a copper foil having a thickness of 8 μm and a width of 9 mm is used as the metal foils 12a and 12b. In order to suppress the skin effect and the proximity effect, it is effective that the metal foils 12a and 12b are as thin as possible. In the case of an audio signal, it is only necessary that the skin effect and the proximity effect can be suppressed with respect to a signal with a frequency up to about 100 kHz. For this purpose, there is no problem as long as the thickness of the metal foils 12a and 12b is thinner than about 15 μm. Practically, a metal foil having a thickness of about 5 to 15 μm can be used. Moreover, although copper foil was used as metal foil 12a, 12b in this embodiment, metal foil, such as not only copper foil but tin foil, aluminum foil, and silver foil, can be used.

  As for the positional relationship in the width direction between the insulating tape 11a and the metal foils 12a and 12b coated with the adhesive, the metal foils 12a and 12b are stuck in parallel so as not to contact each other, and are not exposed to the outside of the insulating tape 11a. It is necessary. Furthermore, the interval between the metal foils 12a and 12b is required to be a distance that does not cause dielectric breakdown when a voltage is applied between the metal foils 12a and 12b. The positional relationship depends on the width of the insulating tape and the metal foil. Further, it is appropriately selected depending on the number of rows of the metal foil to be attached.

  The main body 01 in which the metal foils 12a and 12b are attached to the insulating tape 11a coated with the adhesive 10 as described above is cut in the width direction with a predetermined length, and the metal foils 12a, 12a, The audio terminals 1 were formed by joining the lead terminals 13a, 13b, 13c, and 13d to 12b by soldering or the like.

  In order to put the audio cable 1 of this embodiment into practical use, a pressure-sensitive adhesive 10 is newly applied to the surface of the main body 01 where the metal foils 12a and 12b are exposed as shown in FIGS. An insulating tape 11b is affixed to protect the metal foil surface.

  Further, if a load is applied to the lead terminal 13 as it is, the joint portion with the metal foil is easily damaged, and therefore measures such as solidifying the vicinity of the joint portion with a cured resin or the like are taken.

Further, in order to increase the commercial value, a measure of covering with a flexible braided tube or the like is also adopted in this embodiment.
(Second Embodiment)

  5 is a perspective view showing a second embodiment of an audio cable according to the present invention, FIG. 6 is a cross-sectional view of the B surface of this embodiment, and FIG. 7 is a perspective view showing the internal structure of the main body. FIG. 8 is a partially developed perspective view showing a joined state of the lead terminals.

  In the audio cable 2 of the present embodiment, the main bodies 01a, 01b, and 01c of the audio cable 1 of the first embodiment are stuck together in the width direction to form a laminate as shown in FIG. 6 and FIG. The lead terminals 13a, 13b, 13c, and 13d are joined by soldering or the like so as to be joined to the metal foil portions of all the layers at both ends thereof, thereby forming the main body 02. In the present embodiment, the number of overlaps is three, but the number is not limited to this. In this embodiment, the number of rows of metal foil in one stage is two, but the number is not limited to the number of rows as in the first embodiment.

  The pressure-sensitive adhesive 10, the insulating tape 11, the metal foil 12, and the lead terminals 13a to 13d used in the present embodiment have the same materials and dimensions as those in the first embodiment.

  In the present embodiment, the following method is used to join the lead terminals 13a to 13d to both ends of the laminated metal foils 01a, 01b, and 01c. That is, among the three main bodies 01 to be laminated, the length of 01b from 01a is shortened by 5 to 10mm, and the length of 01c from 01b is shortened by 5 to 10mm. , About 2.5 mm to 5 mm is exposed in the length direction. By arranging in this way, the lead terminals 13a to 13d can be joined to the metal foil of all layers.

In order to put the audio cable 2 of this embodiment into practical use, the same measures ([0018], [0019], [0020]) as in the first embodiment are taken.
(Third embodiment)

  FIG. 9 is a perspective view showing a third embodiment of an audio cable according to the present invention, FIG. 10 is a cross-sectional view of the C surface of this embodiment, and FIG. 11 is a partially developed perspective view of this embodiment. is there.

  The audio cable 3 is bonded to the audio cable 1 of the first embodiment or the audio cable 2 of the second embodiment via an adhesive insulator 14 made of an electrical insulator as shown in FIGS. More conductor paths are provided.

  In the example of the present embodiment, two main bodies 02 (02a, 02b) are used. However, the adhesive insulator 14 is interposed each time the main bodies 02 are stacked, regardless of the number of used bodies.

  As the adhesive insulator 14 which is an electrical insulator, a 1 mm thick butyl rubber sheet having substantially the same width and length as the main body 02 was used. A wide variety of materials can be used as the adhesive insulator, which is an electrical insulator, but butyl rubber, which is excellent in vibration absorption and adhesion, was used.

  Since the thickness of the adhesive insulator 14 affects the interlayer capacitance between the respective conductors, it is determined according to the application.

In order to put the audio cable 3 of this embodiment into practical use, the same measures ([0019], [0020] as in the first embodiment are taken).
(Fourth embodiment)

  FIG. 12 is a perspective view showing a fourth embodiment of an audio cable according to the present invention, FIG. 13 is a cross-sectional view of the D surface of the present embodiment, and FIG. 14 is a cross-sectional view of the E surface of the present embodiment. 15 is a structural diagram of a coaxial cable used in this embodiment.

  The audio cable 4 according to the fourth embodiment will be described by taking as an example a case where only one strip of the metal foil 12 is used in the audio cable 1 according to the first embodiment. The core wires 16 of the coaxial cables 15a and 15b are joined to both end faces of the metal foil 12a of the main body 01, and an insulating tape 11b coated with an adhesive 10 is applied to the surface where the metal foil 12a is exposed. After the adhesive insulators 14b and 14c made of an insulator are bonded together, a metal foil 12c having a thickness of 15 μm or less is attached to the outer peripheral portion so as to cover the outer peripheral portion, and the shield wire portions of the coaxial cables 15a and 15b 17 is joined to the metal foil 12c to obtain a shielding effect. In this embodiment, the main body 01 of the audio cable 1 is used as an example, but the present invention can also be applied to the main body of the audio cable 2 or 3.

  As in the third embodiment, the adhesive insulators 14b and 14c use a butyl rubber sheet having a thickness of 1 mm, substantially the same width and the same length as the main body 01, and the metal foil 12c is a copper foil having a thickness of 8 μm and a width of 55 mm. Was used to cover the entire butyl rubber sheet.

  Since the thickness of the adhesive insulator 14 is a determinant of the electrical characteristic impedance of the audio cable 4, it is determined according to the application.

  For the audio cable 4 of this embodiment, in order to put it to practical use, measures are taken such that the outer peripheral portion of the metal foil 12c is further affixed with an adhesive insulating tape and the joint portion of the coaxial cable 15 is solidified with a cured resin or the like.

  In order to increase the commercial value, a measure of covering with a tube or the like is also adopted.

Specific examples

When the product of the present invention is specifically implemented, it is performed under the following conditions.
1. The length is determined according to the distance of the part where the product of the present invention is used.
2. The number of layers of the main body 01 is determined by the amount of current of the circuit in which the product of the present invention is used.
3. Depending on the number of circuits in which the product of the present invention is used, the number of rows of metal foils 12 attached to the main body 01 and the number of layers of the main body 02 are determined.
4). In order to connect the product of the present invention to the target portion, the shape of the lead terminal 13 is determined in accordance with the application. The lead terminal 13 is not limited by the shape of a single wire, a stranded wire, a ribbon wire, a bare wire, a covered wire, or the like, but it is desirable to make it as short as possible in order to fully exhibit the effects of the product of the present invention. .

(Specific Example 1)
As a specific example 1 of the present invention, an audio cable 2 shown in FIG. 5 is connected between an output terminal of an audio amplifier and an input terminal of a speaker system and used as a speaker cable. In addition, in order to use for the below-mentioned sound quality evaluation test, the product of the present invention in which the lead terminal 13 has a length of 10 cm and the total length of the main body 02 is 2 m was manufactured.

(Specific Example 2)
As a second embodiment of the present invention, the audio cable 3 shown in FIG. 9 is connected between two circuit output terminals of a bi-wiring compatible audio amplifier and between a high-frequency terminal and a low-frequency terminal of a speaker system. To use. Also in the product of the present invention, in order to be used for a sound quality evaluation test described later, a product of the present invention was manufactured in which the lead terminal 13 had a length of 10 cm and the total length was 2 m, as in the first specific example.

  In addition, the bi-wiring method provides dedicated terminals for the high-frequency speaker circuit and the low-frequency speaker circuit in the speaker system, and feeds power from the audio amplifier to the high-frequency terminal and low-frequency terminal using different cables. This is a sound quality improvement method. Therefore, normally, two sets of speaker cables are used, but the product of the present invention can supply power in one set.

(Specific example 3)
As a specific example 3 of the present invention, an audio cable 4 shown in FIG. 12 is connected to an output terminal of a minute signal device such as a CD player and an input terminal of an audio amplifier to form a minute signal line cable. It is what you use. In this case, plugs are attached to the ends of the coaxial cables 15a and 15b. In addition, in order to use for a sound quality evaluation test described later, the length of the coaxial cables 15a and 15b was set to 8 cm, RCA plugs were attached to both ends, and a product of the present invention having a total length of 1 m was manufactured.

(Specific Example 4)
As a fourth concrete use example of the present invention, the present invention is used as a wiring cable in a housing of an audio device. For example, the audio cable 2 or 3 is suitable for the output system wiring in the audio amplifier and the wiring in the speaker system. For wiring that requires an electromagnetic shield, such as a CD player or the minute signal system of the audio amplifier. The audio cable 4 is optimal.

Evaluation test

  An evaluation test was conducted using the product of the present invention of the specific example 1 as the test sample 1, the product of the present invention of the example 2 as the test sample 2, and the product of the present invention as the example 3 as the test sample 3. For comparison, the same wire rod as the lead terminals used for the test sample 1 and the test sample 2 is prepared with a length of 2 m, and one set is used as the comparison sample 1 and two sets are used as the comparison sample 2. Further, 1 m of the same coaxial cable used for the test sample 3 was prepared, and the same RCA plug was attached thereto to obtain a comparative sample 3.

These test samples were connected to an audio apparatus by the following method, and the reproduced sound quality was evaluated.
1. Evaluation method for test sample 1 and test sample 2 The test sample 1 and the comparative sample 1 are connected alternately between the output terminal of the audio amplifier and the input terminal of the speaker system, and the test sample 2 and the comparative sample 2 are alternately connected. Evaluate playback sound quality.
2. Evaluation method for test sample 3 The test sound quality is evaluated by connecting the test sample 3 and the comparative sample 3 alternately between the output terminal of the CD player and the input terminal of the audio amplifier.

  Although it is possible to measure distortion and frequency characteristics of audio equipment as a method for evaluating the performance of equipment including cables, there is no method for qualitatively and quantitatively measuring differences in sound quality. It is common to grasp and evaluate the auditory characteristics with the ears. In the evaluation tests 1 and 2 above, A, B, and C, who are proficient in audio, were asked to use their own audio equipment.

  Table 1 shows the evaluation test results of Mr. A, B, and C3. In any of the evaluation results, significant improvement in sound quality was observed by using Test Sample 1, Test Sample 2, and Test Sample 3. These evaluation test results are considered to indicate that the audio cable according to the present invention contributes to the sound quality improvement of the audio apparatus very effectively.

It is a perspective view which shows 1st Embodiment of the cable for audio. It is sectional drawing of the cable for audio shown in FIG. It is a perspective view of the main body which shows 1st Embodiment of the cable for audio. It is a partial expansion perspective view which shows the joining state of the extraction terminal of the cable of 1st Embodiment of the cable for audio. It is a perspective view which shows 2nd Embodiment of the cable for audio. It is sectional drawing of the cable for audio shown in FIG. It is a perspective view which shows the lamination | stacking state of 2nd Embodiment of the cable for audio. It is a partial expansion perspective view which shows the joining state of the extraction terminal of the cable of 2nd Embodiment of the cable for audio. It is a perspective view which shows 3rd Embodiment of the cable for audio. FIG. 10 is a cross-sectional view of the audio cable shown in FIG. 9. It is a partial expansion perspective view showing a 3rd embodiment of an audio cable. It is a perspective view which shows 4th Embodiment of the cable for audio. It is sectional drawing of the cable for audio shown in FIG. It is sectional drawing which shows the joining state with the drawer | drawing-out coaxial cable of the audio cable shown in FIG. It is a structural diagram of a coaxial cable used as a lead terminal in the fourth embodiment of the audio cable.

Explanation of symbols

10 Adhesive 11 (11a, 11b) Insulating tape 12 (12a, 12b, 12c) Metal foil 13 (13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h) Drawer terminal 14 Adhesive insulator 15 (15a, 15b) ) Drawer coaxial cable 16 Coaxial cable core wire 17 Coaxial cable shield wire 18 Coaxial cable inner coating 19 Coaxial cable outer coating 01 Body of audio cable 1 02 Body of audio cable 2

Claims (4)

A main body formed by affixing one or more metal foils having a thickness of 15 μm or less to an insulating tape coated with an adhesive in parallel at a predetermined interval, and each of the metal foils at both ends of the main body An audio cable characterized in that a lead-out terminal is joined with an electrical connection. An audio cable, wherein the main body is laminated and adhered in multiple layers, and the lead-out terminals are joined to the metal foils of all layers in each row. 3. An audio cable according to claim 1 or 2, wherein a plurality of conductor paths are integrally formed by interposing a plurality of these with an adhesive insulator made of an electrical insulating material interposed therebetween. After the main body portion is protected by an adhesive insulator made of an electrical insulating material in claim 1 to claim 3, the metal foil is attached to the outer peripheral portion so as to cover the outer peripheral portion, and a lead terminal is further provided. An audio cable characterized in that a core wire portion and a shield wire portion are joined to an outer peripheral metal foil as a coaxial cable.

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