JPS59146408A - Impressing device of record erasing magnetic field for photomagnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a practical record erasing magnetic field applying device which has a small and lightweight structure and small power consumption, by shifting a permanent magnet for record erasing magnetic field by means of an electromagnet to control the direction and intensity of the impressed magnetic field. CONSTITUTION:A permanent magnet 1 is magnetized with its U-shaped side defind as an S(N) pole, and the recessed part of the magnet 1 is buried by the copper of a rod form having its specific gravity approximately equal to the magnet 1. The rotary shafts 3a and 3b are attached to the magnet 1 with an adhesive. A shaft holder 4 presses a position prescribing part 3b1 of the shaft 3b at its both sides and prescribes the direction of the magnet 1. In a record erasion mode, an electromagnet 5a for revoltion of the magnet 1 revolves the magnet 1 so that the magnetization of the magnet 1 is turned vertical to a photoelectric magnetic recording medium 7. While the magnet 1 is turned by an electromagnet 5b for revolution of magnet 1 in a reproduction mode or other modes so that the magnetic force of the magnet 1 is set parallel to the medium 7. In a recording mode, the S(N) pole of the magnet 1 at the buried side of a copper rod 2 is turned to the discoid medium 7 by means of an electromagnet 5a. While said pole is turned in the opposite side in an erasion mode.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to recording and erasing information thermomagnetically.
(This is related to a recording/erasing magnetic field application device for magnetic recording media.) This IC: 1-Rewriting using a box-plane magnetized film on a magnetic recording medium + iJ function. It:'r + density recording media will be widely used in the first period (JSJ).

1. The 474 composition of the Yangsong Dynasty and its problems. The ease of erasing records varies depending on the type of medium (FJI), but Tb Fe, a rare earth transition metal alloy thin film, is considered to be a promising C1 magnetic recording medium. GdTb Fe
In such cases, a recording magnetic field of about 100 to 3,000 e and an erasing magnetic field of about 150 to 40,008 e are required. Conventionally, such recording erasing magnetic fields were mainly supplied by electromagnets, but in order to obtain a magnetic field of 508, the electromagnets and their power supplies had to be larger and heavier. When an electromagnet and an optical head are integrated, the disadvantage is that the weight prevents high-speed information retrieval. Even when a recording/erasing magnetic field is supplied by a permanent magnet, the method of reversing the direction of the applied magnetic field and adjusting the intensity is manual, which is impractical.

OBJECTS OF THE INVENTION An object of the present invention is to provide a practical recording and erasing magnetic field applying device for magnetic recording media that is small and light and can be driven with low gravity.

Structure of the Invention The present invention is designed to adjust the direction and intensity of the applied magnetic field by moving a permanent magnet for recording/erasing magnetic field using an electromagnet.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is a permanent magnet made of SmCo material, 2 is a copper rod, 3a, 3b are rotating shafts, 4 is a shaft holder, 52L, 5b
6 is a permanent magnet rotating electromagnet, 6 is a bearing and a cover,
These constitute a recording/erasing magnetic field applying device. Numeral 8 is a disk-shaped magneto-optical recording medium, and numeral 8 is an optical head.

A recording/erasing magnetic field is applied to the magneto-optical recording medium 7 by the permanent magnet 1, and its shape is shown in FIG. Magnetic I~
, fill the open part with rod-shaped copper whose specific gravity is almost equal to that of the permanent magnet, and rotate n1 as shown in Fig. 3(a) and (b).
Attach la and 3b with adhesive. The shaft holder 4 presses the position defining portion 3b of the rotating shaft 3b from both sides and holds the permanent magnet 1.
Specifies the orientation of The electromagnet 6a for rotating the permanent magnet during recording and erasing rotates the permanent magnet 1 so that the magnetization of the permanent magnet 1 is directed perpendicularly to the magneto-optical recording medium 7.

On the other hand, during reproduction and other other operations, the permanent magnet 1 is rotated by the permanent magnet rotating electromagnet 6b so that the magnetic force of the permanent magnet 1 is directed horizontally to the magneto-optical recording medium 7.

When recording and erasing using the same laser beam in magneto-optical recording, an erasing magnetic field larger than the recording magnetic field is required. is directed toward the disk-shaped magneto-optical recording medium 7, while the opposite side is directed during erasing.

In the Gd Tb Fe recording film used in this example, the laser power (peak value) smW, laser path/l/swidth Q, 1~
In 1 μsec, a recorded bit with a recording magnetic field of 20 oooe can be completely erased using the same laser beam and an erasing magnetic field of 4000 e. In this embodiment, a permanent magnet 1 having the dimensions shown in FIG. 2 is used, and a recording magnetic field 2000e and an erasing magnetic field 4000e are generated by placing the rotating shafts 3a and 3b of the permanent magnet 1 at a distance between the disk-shaped magnetic recording media 7 and 13. Obtained.

According to the recording/erasing magnetic field applying device for a magneto-optical recording medium of the present invention, which has been described in detail, the components for supplying the recording/erasing magnetic field can be made smaller and lighter, and the driving power can be reduced for recording, erasing, and reproducing. 51
It is needed only when replacing the magnetic field, and can be supplied with a dry cell battery.Also, outside the recording/erasing magnetic field, permanent magnetism (-1 magnetization is directed horizontally to the recording medium, so recorded information is not erroneously affected by the recording/erasing magnetic field. There is no risk of damage due to
, and the effect is a dog.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the device of the present invention.
)) are the shape diagrams of the Hikumamagaki 1 and the rotating shaft, respectively. 1...Permanent magnet, 2...Copper bar, 32L
, 3b...rotating shaft, 4...shaft holder,
5a, 5b... Electromagnet for permanent magnet rotation, 6...
...Bearing is kanka<-, 7...Magneto-optical recording medium, 8...Soto to 0 science. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 (L:L)0)+ Figure 3 (αl (t)1

Claims (1)

[Claims] , Y, is configured to perform the reversal of the horn direction and adjustment of the strength of the applied magnetic field during recording and erasing of permanent origin, which supplies the applied magnetic field necessary for erasing records on the magnetic recording medium. /ζ A recording quenching magnetic field application device for a magneto-optical recording medium characterized by the following.