Cryocooler-Cooled Split-Paired Magnet for Anisotropic Conductive Sheet Production

A magnet that allows horizontal as well as vertical access to the magnet center is suitable for industrial applications. We designed and fabricated a split-paired magnet cooled with two G-M refrigerators. The magnet has a vertical room-temperature bore of 400 mm in diameter and a horizontal room-temperature gap of 73 mm. Its design value of field uniformity around the magnet center is 0.53% in a space 200 mm in diameter and 50 mm in height. The magnet successfully operated up to 3 T. It was applied to produce anisotropic conductive sheets. Anisotropic conductive materials that are composed of dispersed contacts in polymer film are indispensable for electrical connections in multimedia devices. The magnet was combined with a sheet-forming machine that could press a mold up to 5 tons and 473 K. By using the mold with finely arranged ferromagnetic pins, the production of anisotropic conductive sheets with highly dense contacts and high reliability was successfully achieved.