| 摘要 |
A coaxial cable has an external diameter no greater than 160 microns (0.16 mm). Preferably it comprises an outer conductor having a metallised layer carried on an insulating member which itself is carried on the inner conductor. It is used with an ultrasound catheter carrying an array of 64 piezo-electric transducers (100, Figure 1). The cable (Figure 7) has an inner Cu-Sn conductor (200), an insulating layer (210) of PFA, an electroless coating (220) of Cu and an outer insulating layer (230). The cable may be made by passing a copper filament 400 through a tube 403 which acts as a sacrificial anode in a sputtering process, or has linings 404 of different materials to give the required layers. Alternatively, in a batch process (Figure 9), a plurality of filaments (500) are arranged around an anode (501) and the required layers sputtered on by a surrounding sacrificial cathode (502) or a cathode having a lining (503). <IMAGE> |
