JPS6025002A - Magnetic recording and reproducing device - Google Patents

Abstract

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.

Description

[Detailed description of the invention] The present invention particularly relates to a high-density magnetic recording/reproducing device.

Conventionally, perpendicular magnetization methods and magneto-optical recording methods have been studied as high-density magnetic recording and reproducing apparatuses, but they still have the drawback of not being able to record and reproduce magnetic media at a sufficiently high density.

The present invention is characterized in that it performs extremely fine and high-density recording using an electron beam.

One of the things that has hindered the development of higher density magnetic recording in the past is the difficulty of developing magnetic heads. That is, magnetism has a large fringe effect due to its characteristics, and it is difficult to reduce the effective head gap to about 1 μm or less. Magneto-optical recording performs recording by focusing a laser beam and locally heating a magnetic material, but there are internal problems with the laser and optical system. Furthermore, both methods have great difficulty in reproducing.

The present invention uses an electron beam to heat a very small portion of a magnetic material near the cue point, and simultaneously applies a signal magnetic field to perform high-density recording.

FIG. 1 shows an embodiment of the invention. Reference numeral 1 denotes a vacuum container, which is evacuated through an exhaust pipe 7. 2 is a disk with a magnetic surface,
It rotates from a motor 9 via a drive unit 5. Reference numeral 3 denotes an electron gun whose electron beam 4 passes through a signal coil 6 and hits the disk 2 for rotational scanning.

Note that the potential of 6.2 is set to an appropriate value so as to converge the electron beam. When the magnetic surface of 2 is heated near the cue point by the electron beam and at the same time a magnetic field is applied by the coil 2, strong signal magnetization occurs after cooling, as in the case of magneto-optical recording.6 The configuration may be in the form of a magnetic head so that the electron beam passes through the gap, or the magnetic field may be applied from the back surface of the magnetic material.

Furthermore, as described in the specification of the inventor's earlier patent application No. 1983, a certain signal is recorded on the disk 2 in advance, and the phase portion is partially or completely erased by heating with an electron beam. Good too. In this case, the signal coil is not required; the electron gun, signal coil, motor drive unit, etc. are energized through airtight leads from the vacuum container paper 8 as shown.

FIG. 2 shows a playback device. The recorded magnetic disk 2 is exposed to a light source 10 as in the magneto-optical case. The polarization plates 11 and 12 and the photoelectric converter 13 can be used to rotate the plane of polarization due to the Faraday effect caused by magnetic recording, or to reproduce it by other methods.
As is well known, this method has a poor S/N ratio unless the surface is treated.

Although conventional magnetic heads can also be used for reproduction, it is not easy to manufacture one with an effective gap of a fraction of micrometers.

FIG. 3 shows a magnetic recording and reproducing apparatus according to the present invention. The recorded disk 2 is scanned in a vacuum container by an electron beam 4' of an electron gun 3', but if the beam is oblique to the recording magnetic field, the reflected beam 4'' is deflected by the recording magnetic field. The electron beam 3' should be made much weaker than the beam 3 in Fig. 1 to prevent erasure from occurring.Of course, the device shown in Fig. 1 may be used by changing the voltage. The electron beam 4'' enters the two electrodes 14 and gives a differential output, which is approximately proportional to the recording magnetic field. This differential output is amplified by the operational amplifier 15 and becomes a signal output.

The reproducing apparatus shown in FIG. 3 is suitable for reproducing a disk recorded by the method shown in FIG. 1, but is of course also effective for reproducing other high-density recording or perpendicular magnetization recording.

Conventionally, there was no suitable method for reproducing this type of high-density recording, and S/
N was defective.

FIG. 4 shows an embodiment of the present invention in which the magnetic medium is placed outside the vacuum container. The magnetic tape 23 is wound onto the reels 21 to 22 in contact with the small hole 18 of the vacuum container 8 with its film side facing up.

Although the tape adheres tightly to the small hole 18 due to atmospheric pressure, it is better to prevent leakage with vacuum grease. The electron beam is 1
Recording is performed in the same manner through the tape 8, but by deflecting the beam 4 by the deflection means 20, the tape can perform high-density oblique recording, allowing long-time, large-capacity recording. A characteristic of electron beams is that they can be easily deflected, and any high-speed deflection is possible. The signal magnetic field may be applied from the back side of the tape. The small hole 18 has a width of several tens of μm to reduce leakage.

FIG. 5 shows a magnetic chip 123 recorded by the device shown in FIG.
A recording button 25 is shown, and parallel diagonal recording is performed as shown.

In the apparatus shown in FIG. 4, a thin film may be provided in the small holes 18 to completely maintain the true density.

Figure 6 shows this pattern. The reference numeral 30 is preferably a thin film of metal, semiconductor mica, or the like, which transmits heat without diffusing it as much as possible. 30 may have a width of about 100 μm or less, which is enough for the electron beam to pass through. In addition, since atmospheric pressure is applied via the magnetic tape, the thickness of 30 can be made as thin as about 10 μm.

The device shown in FIG. 4 may of course be a recording medium in the form of a disk, drum, or the like. Although the apparatus of FIG. 4 can be used for reproduction by reducing the beam energy, it may also be used for reproduction using, for example, the magnetic head of FIG. 2 or another magnetic head.

In the present invention, the magnetic recording medium can be automatically moved and set in and out of the vacuum container, and recent vacuum technology can be operated in a short time.

The present invention is not limited to the above-mentioned specific example and can be modified in various ways.

[Brief explanation of the drawing]

FIG. 1 shows a recording/reproducing apparatus according to the present invention. FIG. 2 shows a recording and reproducing apparatus according to the present invention. FIG. 3 shows a reproduction device according to the invention. FIG. 4 shows a recording/reproducing apparatus according to the present invention. FIG. 5 shows a pattern recorded by the apparatus of FIG. FIG. 6 shows a partial modification of FIG. 4.

Claims (1)

[Claims] A magnetic recording and reproducing apparatus comprising a magnetic recording medium, an electron beam generating means, and a means for scanning the recording medium with the electron beam.