Development of copper-coated aluminum-shielded wire

Aluminum-shielded wires are usually used in short lengths of about 200 millimeters in many electronic devices because of their easy termination. However, some problems have occurred in shield effect. The authors have found that this is due to the increase of contact resistance between the aluminum and the drain wire, which is caused by aluminum oxide. To overcome this problem, they developed a new shield tape composed of aluminum foil laminated with polyester film and having a copper layer over the aluminum face. The contact resistance between the shield tape and the drain wire could thus be reduced and was found to be very stable. A wire spirally wrapped and shielded with this new tape has very stable shield effect when subjected to a humid environment or H2S environment, even in short lengths of 100 mm. The authors also developed a new construction for the spirally wrapped shield which is very useful and reliable for multi-conductor wires having individually insulated and shielded conductors.