JPS60209944A - Device for optomagnetic recording, reproducing and erasing - Google Patents

Abstract

PURPOSE:To enable switching of the magnetic field impressed to a recording medium at a high speed by disposing a magnetic field generating part and a light convergent lend for recording, reproducing and erasing on the sides opposite from each other via a recording medium and using an air core coil as the magnetic field generating part. CONSTITUTION:A laser light source 6 for recording, reproducing and erasing and a light convergent lens 7 are provided above a recording medium 5 having a thin magnetic film for optomagnetic recording. An air core coil 8 for generating a magnetic field, a means 9 for driving the position of said air core coil and a control part 10 which detects the face run-out of the medium 5 and generates the signal for driving the position of the air core oil are provided on the opposite side via the medium 5. The control part 10 detects the face run-out the medium 5 and acts to maintain the specified distance between the coil 8 and the medium 5 at all times by feeding a control signal to the means 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magneto-optical recording, reproducing and erasing device that records, reproduces and erases information using light of a specific wavelength.

(Prior art and its problems) Magneto-optical recording is a type of rewritable optical disk memory. Optical disk memory is considered a new memory to replace the current magnetic disk memory because it is capable of high-density, large-capacity, and high-speed access, and magneto-optical recording is attracting the most attention because of its rewritability.

As shown in FIG. 1, the configuration of a conventionally known magneto-optical recording/reproducing/erasing device includes a recording medium 1. A head section that records, reproduces, and erases information using laser light 2. It consists of a magnetic field generating section 3 for applying a magnetic field to the recording medium 1. In magneto-optical recording, it is necessary to change the direction of the magnetic field applied to the recording medium 1 when recording and erasing information. For this purpose, conventionally, an electromagnet, a permanent magnet, or an air-core coil is used for the magnetic field generating section 3. The magnetic field generating section other than the air-core coil is arranged on the opposite side of the head section 2 with respect to the recording medium 1. A commonly used recording medium 1 is a rare earth transition metal amorphous alloy film, that is, an alloy film of (Gd, Tb, Dy, Ho) and (li'e, Co, Ni) formed on a glass or plastic disk. Recording and erasing each requires an applied magnetic field of 100-200°C. In order to realize recording and erasing at even higher speeds, it is necessary to switch the magnetic field at a speed of 1 μm or less.

When using an electromagnet as the magnetic field generating section 3, 100 to 20
Although it is easy to obtain an applied magnetic field of 0α, there is a limit to responsive operation, and there is a drawback that magnetic field switching cannot be performed at 1 μ(6) or less. Similarly, if a permanent magnet is used as the magnetic field generator 3, it is easy to obtain an applied magnetic field of 100 to 200 µm, but since the switching of the magnetic field relies on mechanical means, the applied magnetic field is less than 1 µ(8). The disadvantage is that magnetic field switching is not possible.

One way to enable fast switching of the magnetic field is to use air-core coils. When using a heart coil, 10
Swipe the magnetic field from 0 to 200α at high speed.

Because the shape of the coil has to be shaped like a hut in order to change the shape of the coil, a method that only fixes the air-core coil near the recording medium will cause fluctuations in the distance between the coil and the recording medium due to surface run-out due to the rotation of the recording medium. This has the disadvantage that it is difficult to apply a constant magnetic field.

(Object of the invention) The object of the present invention is to eliminate such conventional drawbacks,
Sweeps the magnetic field applied to the recording medium at high speed.

It is an object of the present invention to provide a novel magneto-optical recording/reproducing/erasing device which enables the recording and erasing of data.

(Structure of the Invention) According to the present invention, in a magneto-optical recording, reproducing and erasing device that optically detects and reproduces reflected light, a magnetic field generating section and a recording, reproducing and erasing optical converging lens are arranged on opposite sides of each other with a recording medium in between. magneto-optical recording and reproducing, characterized in that the magnetic field generating section is provided with a driving means for keeping the distance between the magnetic field generating section and the recording medium at a predetermined interval, and an air-core coil is used as the magnetic field generating section. An erasing device is obtained.

(Detailed Description of Configuration) The present invention solves the problems of the prior art by adopting the above-mentioned configuration. First, by using an air-core coil as a means for applying a magnetic field to a recording medium, a magnetic field of 100 to 200 mm can be switched at a high speed of 1 μ(6) or less. At the same time, by keeping the distance between the recording medium and the air-core coil constant using the air-core coil movable driving means, a magnetic field of a desired value can be applied to the medium.

The magnetic field generating section, the air-core coil position driving means, and the control section are integrated and have a structure that moves in the radial direction in accordance with the radial movement of the recording/reproducing/erasing laser light source and the light converging lens.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention, in which a laser light source 6 for recording, reproducing and erasing and a light converging lens 7 are provided above a recording medium 5 having a magnetic thin film for magneto-optical recording. On the opposite side are an air-core coil 8 for generating a magnetic field, a position driving means 9 for the air-core coil, and a control unit 10 that detects the leveling up of the recording medium 50 and generates a signal for driving the position of the air-core coil.
This is a configuration with a The recording medium is rotated many times by a rotation motor 11.

The control unit 10 detects the surface runout of the recording medium 5 and sends a control signal to the air-core coil position driving means 9, so as to always keep the distance between the air-core coil 8 and the recording medium 5 constant. As the control section 10, a configuration similar to that of a converging lens focusing point control section of a known optical head is used. The lens 12 is used to detect variations in the distance between recording media attached to the same frame as the air-core coil.

In the embodiment configured as described above, the shape of the air-core coil used and its magnetic properties will be explained. The air-core coil used was a coated copper wire with a wire diameter of 0.11 mφ, an outer diameter of 3.1 nφ, an inner diameter of 0.1 wφ, and a coil length of 0.2111 mm.
The number of turns was 11 m and 30 turns. The inductance of the air-core coil measured with an impedance meter was 1.1 μH. Figure 3 shows the results of the coil-generated magnetic field by varying the distance from the tip of the coil. When the coil current is IA, a magnetic field of 2000 is obtained at 0.2° from the tip of the coil. In addition, by supplying pulsed current to the air-core coil using a current pulser with a load resistance of 50Ω,
It was possible to perform magnetic field switching under
Since the thickness is about 50 μm, a thickness of about 0.2 μm is necessary. Since the distance between the air-core coil and the medium is suppressed to fluctuations of ±1 μm or less by the control unit and position driving means employed in this embodiment, it is possible to stably apply a magnetic field of constant strength to the recording medium. can.

(Effects of the Invention) As explained above, the present invention has the following effects compared to the conventional example.

■By using an air-core coil as the magnetic field generator and employing a mechanism that maintains a constant distance between the air-core coil and the recording medium, it is possible to switch the magnetic field at a high speed of less than 1 μm.

(2) Since the magnetic field generating section is placed on the back surface of the recording medium, it does not interfere with recording, reproducing, or erasing operations, and does not impose restrictions on the head configuration.

(2) By using high-speed magnetic field switching, new data can be recorded by rewriting the already recorded track without erasing one track at a time, and the "erase mode" can be omitted.

(2) Since the magnetic field generated by the air-core coil decreases sharply as the distance from the tip of the coil increases, magnetic interference with the light converging lens focusing drive control means and the air-core coil position drive means does not occur.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional magneto-optical recording/erasing device;
The figure is a block diagram showing one embodiment of the present invention, and FIG. 3 is a diagram showing the generated magnetic field characteristics of the core coil used in the present invention.

Claims (1)

[Claims] In a magneto-optical recording, reproducing and erasing device that optically detects and reproduces reflected light, a magnetic field generating section and an optical converging lens for recording, reproducing and erasing are arranged on opposite sides of the recording medium, and the magnetic field generating section and the recording A magneto-optical recording/reproducing/erasing device characterized in that the magnetic field generating section is provided with a driving means for maintaining a distance from the medium at a predetermined interval, and an air-core coil is used as the magnetic field generating section.