JPS63231802A - Signal transmitting conductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a signal transmission conductor used in audio and electronic equipment, etc., and in particular to a conductor for transmitting signals such as audio and video that has improved transmission characteristics compared to conventional ones. This is about conductors.

[Conventional technology]

Audio and video equipment such as stereo equipment, video equipment, precision measuring instruments, electronic equipment such as computers, etc.
Other signal transmission conductors are used to transmit electrical signals within or between devices. As the signal transmission conductor, annealed tough pitch copper has conventionally been generally used, and some high-grade products have used annealed oxygen-free copper.

[Problem that the invention seeks to solve]

Recently, stereo equipment, video equipment, etc. are required to have increasingly high sound quality and high image quality, and precision measuring instruments, computers, etc. are also required to have improved measurement accuracy and faster calculation speed. It is rare.

In order to meet such demands, it is necessary to use high-quality conductors with very little signal attenuation and phase shift as signal transmission conductors. Conventionally used conductors have relatively large signal attenuation and phase shift, which results in noise or signal disturbances, poor audio and image quality, and inability to perform sufficiently precise measurements. This has caused problems such as the inability to increase the speed.

In order to manufacture such a high-quality conductor with excellent signal transmission characteristics, it is essential to use a material that does not contain ingot defects, impurity segregation, or grain boundaries. Recently, for some high-end audio products, the crystal grains of oxygen-free copper have been coarsened through heat treatment and then cold drawn to a specified size, or ingots or single crystals with a unidirectionally solidified structure are similarly drawn. Wire drawing processing is used. These conductors have significantly fewer grain boundaries than conventional ones, but because they are all subjected to cold working, lattice defects such as dislocations multiply, and these cause electrons in the conductor to grow. This caused scattering, contributing to signal attenuation and phase shift. Furthermore, even if the ingot is used as an ingot without cold working, there will always be dislocations introduced during casting or remaining, and not only dislocation-free crystals but also crystals with low dislocation density will not be used industrially. This was previously impossible to obtain.

[Means for solving problems]

The present invention has been made as a result of intensive research in view of the above points, and its purpose is to provide a high quality signal transmission conductor with little signal attenuation and phase shift. That is, the present invention has a dislocation density of 10" cm/c+
This is a signal transmission conductor characterized by being made of a copper material of fl or less. In order to obtain a conductor with excellent signal transmission characteristics in the present invention, it is necessary that the ingot has no defects, grain boundaries, etc., and for this purpose, an ingot or single crystal with a unidirectional solidification structure is used. is desirable. Also, impurities (C+
By using oxygen-free copper containing almost no gO particles, it is possible to further improve the signal transmission characteristics of the conductor.

Methods for obtaining materials with a low dislocation density and a single crystal or unidirectionally solidified structure include heated mold casting method, rotational pulling method, Bridgman method, floating zone melting method, etc. It is difficult to obtain long materials industrially using the melting method, and the Bridgman method in particular has problems such as the propagation of dislocations due to the frictional stress between the mold and the solidified material. preferable. The signal transmission conductor according to the present invention must not only be cold-worked after solidification, but also must be manufactured with the utmost care to avoid adding strain at the pass line, and furthermore, to obtain a crystal with a low dislocation density. special manufacturing techniques are required.

That is, the first method for obtaining the crystal with a low dislocation density is as follows:
The purpose is to suppress the introduction of dislocations due to thermal stress during the solidification process, and the solidification rate, that is, the casting speed, is set to 100 mm/min.
By suppressing the dislocation density to below, there is no sudden temperature gradient in the growth direction (casting direction) as well as in the radial direction, and it is possible to stably produce a material with a dislocation density of 108 cm / ci or less. For example, Figure 1 shows the relationship between casting speed and dislocation density when producing a unidirectionally solidified material with a diameter of 5 mm using the top-drawing heated mold casting method.By slowing down the casting speed, A material with low dislocation density has been obtained. FIG. 2 shows the relationship between the dislocation density and the signal attenuation.
/ By setting Cll1 or less, the signal attenuation amount can also be reduced to 0.
It is very low, less than 0.002 dB. In order to reduce the temperature gradient in the casting direction, the cooling device may be separated from the ingot, and crystals with a low dislocation density can be obtained in the same way.

The low dislocation density crystal can also be obtained by strain relief annealing after casting. For example, FIG.
This graph shows the relationship between annealing time and dislocation density when strain relief annealing is performed at 00°C. As the annealing time increases, the dislocation density decreases. The reduction in dislocation density is greater in cycle annealing (curve B) than in A). FIG. 4 is an explanatory diagram showing an outline of a heated mold continuous casting apparatus in which the cycle annealing was performed,
1 is a heating mold, 2 is an ingot, 3 is a cycle heat treatment furnace, 4 is a heater, 5 is a casting furnace, 6 is a molten metal, and 7 is a pinch roll. The ingot 2 pulled up from the heating mold 1 is intermittently heated by heaters 4 arranged at regular intervals in a cycle heat treatment furnace 3 in an N2 atmosphere, and the temperature distribution in the longitudinal direction of the ingot at that time is, for example, curve C. It will look like this. The annealing time in the cycle annealing is calculated from the total heater length and the ingot pulling speed.

[Effect]

The signal transmission conductor according to the present invention has low dislocations by slowing the casting speed to reduce the temperature gradient during solidification to suppress the introduction of dislocations due to thermal stress, or by reducing the dislocation density by strain relief annealing. Because of the high density, there is little signal attenuation and phase shift, and the transmission characteristics of audio, video, and other signals are excellent.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

First, FIG. 5 shows an outline of the top-drawing heated mold continuous casting apparatus used to obtain the unidirectionally solidified material. 2 is an ingot, 5 is a casting furnace, 6 is a molten metal, 7 is a vinyl roll, 8 is a mold, 9 is a heating device, and 10 is a water cooling device. The mold 8 is made of graphite and has a cylindrical shape, and a heating device 9 is wound with Kanthal wire.
Since the molten metal 6 is heated to a temperature higher than its melting point by
0, heat is removed along the longitudinal direction, and an ingot 2 having a unidirectional solidification structure is obtained.

Oxygen-free copper materials (conventional example No. 4) manufactured by a normal method using the above-mentioned casting equipment and oxygen-free copper materials whose dislocation density was lowered by slowing down the casting speed or performing strain relief annealing (inventive example) The dislocation density and signal attenuation amount were measured for Nα1 to Nα3) and are summarized in Table 1 together with the manufacturing conditions of the materials. The cycle annealing was carried out by installing a cycle heating heater as shown in FIG. 4 on the upper part of the casting apparatus shown in FIG.

As is clear from Table 1, inventive examples Nα1 to Nα3 with lower dislocation densities all have less signal attenuation and improved signal transmission characteristics than conventional examples No. 4.

〔Effect of the invention〕

The signal transmission conductor according to the present invention has better transmission characteristics for audio, video, and other signals than conventional ones, and can be used not only as a conductor for cables but also as a contact material for connectors, etc., which are the connection parts of various electronic devices. It is also possible to obtain a plate-shaped or even foil-shaped conductor, and it can also be used as a material for lead frames. Specific uses include not only audio and microphone cords, but also video, CT ski gear, and MR.
It has remarkable industrial effects, such as being able to be used as a conductor for various signal transmission purposes, such as for images such as 1, etc., and also for wiring within and between devices such as precision measuring instruments and computers.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing the relationship between casting speed and dislocation density, and dislocation density and signal attenuation, respectively; Figure 3 is an explanatory diagram showing the relationship between annealing time and dislocation density; Figure 4; Fifth
The figure is a schematic explanatory diagram of a heating mold continuous casting apparatus. 1... Heating mold, 2... Ingot, 3... Cycle heat treatment furnace, 4... Heater, 5... Casting furnace,
6... Molten metal, 7... Pinch roll, 8...
Mold, 9... heating device, 10... water cooling device.

Claims (4)

[Claims] (1) A signal transmission conductor characterized by being made of a copper material having a dislocation density of 10^8 cm^3 or less. (2) The signal transmission conductor according to claim 1, characterized in that the dislocation density is reduced to 10^8 cm^3 or less by strain relief annealing. (3) The signal transmission conductor according to claim 1 or 2, wherein the copper material is an ingot or single crystal with a unidirectional solidification structure. (4) The signal transmission conductor according to claim 1 or 2, wherein the copper material is oxygen-free copper.