JPH0673243B2 - Electrical conductor for audio / video equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric wire used for a lead wire, a cord, etc. of an audio / video device represented by a stereo device, a television device, a loudspeaker (PA system) and the like. It is about conductors.

[Prior Art and its Problems] There is a close relationship between the sound quality and image quality of audio / video equipment and the electric conductors used in the equipment, and in particular, electricity using oxygen-free copper with an extremely low oxygen content. The conductor is evaluated to give very good sound quality and image quality.

The present inventors consider that the reason why the electric conductor using oxygen-free copper gives better sound quality and image quality than the electric conductor using tough pitch copper for general electricity is as follows.

In the normal state, metallic copper is composed of an extremely large number of fine crystals, and impurities such as oxides and sulfides are gathered at the boundaries between crystals, that is, grain boundaries. Tough pitch copper for general electric use contains 100 to 500 ppm of oxygen, which is mainly present in grain boundaries in the form of cuprous oxide (Cu ₂ O). Since this cuprous oxide is a polycrystalline semiconductor, tough pitch copper for general electrical use contains not only a mere resistance component but also a capacitance component and a detection component, and it is considered that the units composed of these components are three-dimensionally distributed. You can This means that when tough-pitch copper for general electricity is used as an electric conductor, it works as a capacitive reactance for high frequency components, and audio / video signals, which are composite signals of multiple frequencies, pass through the system to produce each frequency component. Each time, a phase difference is generated, and human hearing is recognized as phase distortion, which hinders faithful reproduction of sound and images. In addition, the amount of attenuation of cuprous oxide due to the detection action varies depending on the frequency, which also contributes to obstruction of faithful reproduction of sound and images in tough pitch copper for general electrical use.

On the other hand, oxygen-free copper has a much lower oxygen content than tough-pitch copper for general electrical use, and therefore contains very little cuprous oxide and other impurities, so that faithful reproduction of sound and images is possible. The number of obstacles is reduced.

Furthermore, the sound quality and image quality of electrical conductors for audio / video equipment are governed by the number of crystal grain boundaries, and even with oxygen-free copper with a very small amount of impurities, there are many crystal grain boundaries. As far as possible, it is clear that faithful reproduction of sound and images is hindered. Incidentally, as the conventional electric conductor made of oxygen-free copper, an annealed copper wire obtained by annealing a wire rod drawn to a final wire diameter by a wire drawing operation at a temperature of about 400 ° C is used. The average crystal grain size is about 0.02 to 0.03 mm, and in the case of a wire having a length of 1 m, for example, about 50,000 fine crystals are connected in the length direction.

The present applicant has drawn an electric conductor using a giant crystallized oxygen-free copper material, and further stretched the giant crystallized oxygen-free copper material in the length direction to orient the thin fibers as if they were bundled. Proposed an electric conductor having a linear crystal structure (Japanese Patent Application No. 58-110426 and Japanese Patent Application Laid-Open No. 60-3808), and it is evaluated in various fields that excellent audio sound quality and video image quality can be realized, which is extremely high industrial level. It has been recognized for its value.

From the above viewpoints, it has been clarified that audio quality and video quality are greatly affected by the content of impurities and the number of grain boundaries. It is newly pointed out by the inventors of the present invention that the content of about 1 ppm is included, which has a delicate influence on sound quality and image quality.

[Object of the Invention] An object of the present invention is to provide an electric conductor capable of realizing more excellent audio sound quality and video image quality than the electric conductors proposed so far.

[Summary of the Invention] An electric conductor for audio / video equipment of the present invention is characterized by comprising a low-gas component high-purity oxygen-free copper wire having an oxygen content of 10 ppm or less and a hydrogen content of 0.5 ppm or less. Is.

The oxygen-free copper used as the electric conductor of the present invention is a low gas component high-purity oxygen-free copper having an oxygen content of 10 ppm or less and a hydrogen content of 0.5 ppm or less. The reason is that signal transmission characteristics are improved by not containing impurities such as cuprous oxide, and when impurities such as cuprous oxide are contained, these become crystal nuclei and the crystal grains become huge. Is hindered. Furthermore, by setting the hydrogen content to 0.5 ppm or less, excellent sound quality and image quality can be realized.

The inventors of the present invention consider that the reason why excellent audio quality and video quality can be realized by using oxygen-free copper having a hydrogen content of 0.5 ppm or less is as follows. That is, according to the quantum theory, hydrogen, which is the smallest atom, can penetrate into the inside of a copper crystal having a face-centered cubic lattice with a re-dense structure, and the movement of free electrons and holes, which is the principle of electrical conduction, can occur. However, resistance should be generated in the form of reduction of the mean free path. If a large number of hydrogen atoms that hinder the movement of free electrons are present in the crystal lattice in this way, the transmission characteristics will have frequency dependence for audio / video signals consisting of multiple component frequencies, and this will have a small effect on human hearing and vision. It is considered to be perceived as distortion.

As a method of reducing the hydrogen content in oxygen-free copper to 0.5 ppm or less, there is a method of holding molten copper under high vacuum in the casting process of oxygen-free copper material.

Further, the oxygen-free copper material is one in which huge crystal grains are formed by annealing at an appropriate high temperature for a predetermined time, and when it is solidified after heating and melting. When stretched in the longitudinal direction by, the fibers are oriented as if they were bundled with fine fibers to form linear crystals.

The enlarging of crystal grains by high temperature annealing is
For example, it can be realized by heating in a vacuum at 800 ° C. or higher or in an inert gas atmosphere for 30 minutes or longer. As a result,
The crystal grain will grow to a giant crystal of about 0.4 mm or more, and since the average crystal grain size of the oxygen-free copper annealed copper wire obtained by ordinary annealing is about 0.02 to 0.03, the grain boundary density is It will be reduced to less than 1/20 due to the huge size of the grains.

Oxygen-free copper material with large crystal grains is drawn to the required final wire diameter by wire drawing or the like. As a result, the giant crystal grains are stretched in the lengthwise direction in proportion to the pull-down ratio to become linear crystals, and are oriented as if the thin fibers were bundled, so the grain boundary density is extremely long in the lengthwise direction. Diluted. That is, the average crystal grain size of the material of oxygen-free copper of 0.5 mm, when the outer diameter is dropped from 1.8 mmφ to 0.18 mmφ, each crystal is stretched about 100 times in the length direction of the material, Since only 20 crystals (or crystal grain boundaries) exist in the length direction per 1 m, the dielectric effect of the crystal grain boundaries, which affects the audio and video signals by distortion, is significantly reduced. Further, in the present invention, since the hydrogen content is extremely low, adverse effects on the audio and video signals can be eliminated to the utmost.

The heating for enlarging the crystal grains needs to be performed in a vacuum or in an atmosphere of an inert gas such as argon gas in order to prevent the oxygen-free copper material from being oxidized. Although the heating time depends on the temperature, it takes at least about 30 minutes to obtain the necessary giant crystals.

It is also possible to obtain a giant cast crystal by melting an oxygen-free copper material in an atmosphere not containing hydrogen and then slowly cooling it.

[Examples of the invention] Examples In the casting process, oxygen content was 5 ppm and hydrogen content was 0.3 p by holding molten copper under high vacuum and performing degassing operation.
Oxygen-free copper material of pm was obtained and the outer diameter obtained by processing this was 1.8 mm
The φ copper wire was held in a furnace in an argon gas atmosphere set at a temperature of 900 ° C. for 1 hour and 30 minutes to make crystal grains huge, and then cooled. The average crystal grain size of this copper wire had grown to 0.6 mm.

Then, draw this copper wire on a wire drawing machine and pull it down to 0.18 mmφ,
An electric conductor with a linear crystal structure was obtained.

Comparative Example A copper wire with an outer diameter of 1.8 mmφ obtained by processing oxygen-free copper having an oxygen content of 5 ppm and a hydrogen content of 1.0 ppm was placed in a furnace in an argon gas atmosphere set at a temperature of 900 ° C. for 1 hour 30 It was held for a minute to enlarge the crystal grains and then cooled. The average crystal grain size of this copper wire had grown to 0.6 mm.

Then, draw this copper wire on a wire drawing machine and pull it down to 0.18 mmφ,
An electric conductor with a linear crystal structure was obtained.

54 electrical conductors according to the examples and comparative examples were collected, and 1.25
We produced a mm ² 2-core speaker cord, cut it to a length of 3 m, and used it to connect the stereo amplifier and the speaker.

When the reproduced sound of the stereo record was auditioned when the electric conductors of the example and the comparative example were used,
In the case of the example, the improvement effect was recognized in two points as compared with the case of the comparative example, that is, a sharp stereoscopic sound image localization and a deep sound field feeling.

Further, a coaxial cable was manufactured by braiding the electric conductors according to the examples and comparative examples and used as an outer conductor, and the coaxial cable was cut into a length of 2 m and used for connecting a television receiver and a video device.

When television images were reproduced using the electric conductors of the example and the comparative example, respectively, it was confirmed that an image with sharper contrast was obtained in the case of the example than in the case of the comparative example.

[Effects of the Invention] As described above, the present invention provides crystal growth of an oxygen-free copper electric conductor that has been dehydrogenated by a method such as holding molten copper under high vacuum, and an oxygen-free copper material. It is intended to provide an electric conductor in which crystal grains are enlarged by operation and then stretched in the lengthwise direction to form a linear crystal in which the grain boundary density in the lengthwise direction is significantly diluted. It becomes possible to further equalize the frequency dependence of the transmission characteristics of signals and video signals, and it becomes possible to eliminate the factors that are perceived as a minute distortion in the human visual sense. Therefore, by using this for a lead wire, a cord, etc. of an audio device, a video device, etc., it becomes possible to realize more excellent audio sound quality and video image quality.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Seya, 1500 Kawajiri-cho, Hitachi-shi, Ibaraki 1500 Toraura factory, Hitachi Cable Co., Ltd. (72) Inventor, Yuu Hoshikawa 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd. Hidaka Plant (56) Reference JP-A-59-167904 (JP, A) "REVUE DU SON" No. 281, No. 2, October 21, 1976-November 18, 1976 P. 185-191

Claims (2)

[Claims] 1. An electric conductor for audio / video equipment, characterized by comprising a high purity oxygen-free copper wire having a low gas content and having an oxygen content of 10 ppm or less and a hydrogen content of 0.5 ppm or less. 2. The wire has an oxygen content of 10 ppm or less, which is obtained by enlarging crystal grains by a crystal growth operation, and a hydrogen content.
The electric conductor for audio / video equipment according to claim 1, which is a wire having a linear crystal structure obtained by drawing a high-purity oxygen-free copper material having a low gas content of 0.5 ppm or less.