An apparatus for producing a magnetic field, which changes as a function of an information signal

摘要

PURPOSE:To reduce the size and weight of the above device and to facilitate the position control to detect a change in the spacing with a recording medium and to maintain the state of adequately approaching the recording medium by providing a capacity detecting electrode part to be disposed to face the recording medium. CONSTITUTION:The recording signal magnetic field generated when the current corresponding to a recording signal is supplied to a coil part 30 wound to enclose a central leg part 29a in a magnetic core part 29 mounted to one surface side of a substrate 25 acts efficiently on the recording medium 10 positioned on the other surface side of the substrate 25 through the central leg part of the magnetic core part 29 penetrating the through-hole provided in the substrate 25. The magnetic core part 29 wound with the coil part 30 is mounted to one surface of the substrate 25 and the capacity detecting electrode part 28 is mounted to the other surface of the substrate 25 as the part to form a prescribed thin-film pattern on the other surface of the substrate 25 and is disposed to face the recording medium 10. The entire part is constituted small in size and weight in this way; in addition, the change in the spacing with the recording medium is easily detected. The position control to maintain the state of adequately approaching the recording medium is facilitated.