Miniature high frequency coil assembly or transformer

Claim 1

A miniature high frequency coil assembly or transformer, comprising: a substrate having a plurality of electrodes thereon and a first through bore; an external core member mounted on said substrate, said external core member having a second through bore and made of a magnetic material, the arrangement of said external core member on said substrate being such that the longitudinal axis of said second through bore is substantially perpendicular to the surface of said substrate; a coil member having a central bore disposed on said substrate and within said second through bore, and disposed coaxial with longitudinal axes of said first and second through bores; an elastic material casting in said second through bore and about said coil member internally in said central bore and circumferentially thereof, and having a core-receiving bore therein, said core-receiving bore being disposed coaxially with the longitudinal axis of said core member and cast so as to have, in a stepped bore, first and second bore portions each having a different inner diameter, said first bore portion being further disposed axially from said substrate than said second bore portion and having an inner diameter larger than said second bore portion; and a movable core of a magnetic material movably received in said core-receiving bore and having first and second portions each having a different diameter, said first portion of said movable core having a screw thread along its length and with means for turning the same as its one end and having a larger diameter than said second portion of said movable core, and said first and second bore portions of said core-receiving bore respectively receiving said first and second portions of said movable core.