| 摘要 |
PURPOSE:To attain high density recording by heating a magnetic body at an extremely small part with an electron beam almost up to a Curie point, and applying a signal magnetic field. CONSTITUTION:A vacuum vessel 1 is evacuated through an air release pipe 7. A disk having a magnetic surface is rotated by a motor 9 through a driving part 5. The electron beam 4 from an electron gun 3 strikes the disk 2 through a signal coil 6 to make a rotary scan. The magnetic surface 2 is heated almost up to the Curie point with the electron beam and when a magnetic field is applied by the coil 6 at the same time, the surface is magnetized intensely with a signal after cooling. The recorded disk 2 is scanned with the electron beam 4' of an electron gun 3' in the vacuum vessel in reproduction, and the reflected beam 4'' is deflected by a recording magnetic field if the beam slants to the recording magnetic field. The electron beam 3 of the gun 3 is so much weaker than that of the gun 3 as to inhibit erasure. The deflected electron beam 4'' enters an electrode 14 to generate a differential output, which is nearly proportional to the recording magnetic field. This differential output is amplified by an operational amplifier 15 into a signal output. |
