JP2503402Y2 - Magneto-optical recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a magneto-optical recording apparatus for recording an information signal on a magneto-optical disk using a light beam and an external magnetic field.

[Conventional technology]

Conventionally, a magneto-optical disk has been proposed as an information signal recording medium that can erase a recorded information signal and re-record a new information signal.

This magneto-optical disk is on one side of the disk substrate,
It is formed by forming a magnetic thin film recording layer having perpendicular magnetization anisotropy. This magnetic thin film recording layer loses its coercive force by being irradiated with a light beam and being heated above the Curie point, and is magnetized in the direction of this magnetic field by applying an external magnetic field with this coercive force lost. The information signal is recorded by utilizing the property of retaining the magnetized state by lowering the temperature below the Curie point in the magnetized state.

As a magneto-optical recording device using a magneto-optical disk having a magnetic thin film recording layer having such a property as a recording medium,
A device configured as shown in FIG. 3 is known.

The magneto-optical recording apparatus shown in FIG. 3 emits a light beam from an exciting coil 20 for generating an external magnetic field and a semiconductor laser, facing one surface of a magneto-optical disk 24 which is rotated by a disk rotation driving device. And a light source emitted from the light source and an optical system 21 including an objective lens 25 for focusing the light beam emitted from the light source on the magnetic thin film recording layer of the magneto-optical disk 24. It becomes.

The exciting coil 20 is wound around a core 22 made of a material having high magnetic permeability.

The magneto-optical recording head device 23 is operated to move in the radial direction of the magneto-optical disk 24 via a head moving means (not shown).

The magneto-optical recording device configured as described above focuses the light beam emitted from the light source of the magneto-optical recording head device 23 by the objective lens 25 and irradiates the magnetic thin film recording layer of the magneto-optical disk 24 with this light beam. The irradiated portion is heated above the Curie point and an external magnetic field in a fixed direction is applied from the exciting coil 20 to erase the information signal recorded in the magnetic thin film recording layer, or the information signal to be recorded. A desired information signal is recorded by applying an external magnetic field modulated according to the above.

[Problems to be solved by the device]

By the way, in the magneto-optical recording device in which the conventional magneto-optical recording head device 23 is arranged on one surface side of the magneto-optical disk 24, the magnetic flux generated from the exciting coil 20 becomes an open loop and the electro-magnetic conversion efficiency is extremely poor, A perpendicular magnetic field cannot be efficiently applied to the magnetic thin film recording layer of the magneto-optical disk 24.

Therefore, the present invention provides a magneto-optical recording device that enables an external magnetic field to be efficiently applied from a magneto-optical recording head device to a magneto-optical disk and enables recording of an information signal with good recording characteristics. It was proposed for that purpose.

[Means for solving the problem]

A magneto-optical recording apparatus according to the present invention, which is proposed to achieve the above-mentioned object, includes a soft magnetic material provided over the entire surface of a recording medium layer provided on one surface of a substrate of a magneto-optical disk. An optical system having an objective lens which is arranged on the other surface side of the substrate on which the recording medium layer of the magneto-optical disk is provided and which faces the other surface, and which irradiates a light beam in a focused state on the recording medium layer. The focus point of the light beam is hollow and surrounds the head part and the objective lens provided on the side where the objective lens is provided in the optical head part, and the tip end side of the position where the objective lens is provided. A magneto-optical head device comprising: a core formed in a taper shape toward the front side; and a magnetic head part including a coil wound around the taper portion of the core along the taper shape. It is intended to.

[Action]

In the magneto-optical recording apparatus according to the present invention, the magnetic flux generated from the coil of the magneto-optical recording head apparatus is concentrated on the recording medium layer of the magneto-optical disk from the tip of the tapered core. Then, the magnetic flux applied to this recording medium layer constitutes a magnetic path to the soft magnetic plate provided over the entire surface of the recording medium layer, and is emitted from the optical head section and irradiated to the recording medium layer. The focused light beam is concentrated near the focus position.

〔Example〕

Hereinafter, a specific embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the magneto-optical recording apparatus according to the present invention is provided with a recording medium layer 22 formed by depositing a magnetic thin film on one surface of a disk substrate 21, and the recording medium layer 22 is formed. A magneto-optical disk 20 provided with a soft magnetic plate 23 having a high magnetic permeability and a high magnetic flux density over the entire surface, and the magneto-optical disk 20 is arranged on the other surface side opposite to one surface provided with the recording medium layer 22. And a magneto-optical recording head device 1 provided.

As shown in FIG. 1, a magneto-optical recording head device 1 constituting this magneto-optical recording device includes a semiconductor laser 2 for emitting a light beam, and a collimator lens for collimating the light beam emitted from the semiconductor laser 2 into parallel light. 3, a polarization beam splitter 4 for separating a light beam emitted from the semiconductor laser 2 and a returning light beam reflected from a magneto-optical disk 20 described later, and a light beam emitted from the semiconductor laser 2 to the magneto-optical disk 20. , An objective lens 5 for irradiating the magnetic thin film recording layer 22 in a focused state, a detector 6 such as a photodetector for detecting the returning light beam from the magneto-optical disk 20 separated by the polarization beam splitter 4. An optical head portion 11, a hollow core 7a made of a high-permeability material and arranged around the outer peripheral side of the objective lens 5 of the optical head portion 11 It consists magnetic head 7 serving as a stray field generating means comprising a wound exciting coil 7b around the outer periphery of 7a composed.

The tip end 7c side of the core 7a forming the magnetic head portion 7 of the magneto-optical recording head device 1 is tapered.
That is, the tip 7c of the core 7a, as shown in FIG.
It is tapered so as to be directed to the focal point of the light beam focused by the objective lens 5 and applied to the magnetic thin film recording layer 22 of the magneto-optical disk 20.

Then, as shown in FIG. 1, the exciting coil 7b is formed on the outer peripheral surface of the tip end portion 7c formed as a tapered portion of the core 7a.
Is wound and provided.

Also, a magneto-optical disk used as a recording medium for information signals.
Reference numeral 20 denotes a drive motor 12 and a spindle shaft 13 of the drive motor 12, which is integrally mounted on the turntable 14 of the disk rotation drive device including a turntable 14 which is rotationally driven by the drive motor 12 to rotate. Operated. The magneto-optical disk 20 is mounted on the turntable 14 with the other surface on the side where the soft magnetic plate 23 is arranged facing the turntable 14.

The magneto-optical recording head device 1 is moved in the radial direction of the magneto-optical disk 20 via a head moving means (not shown).

Next, a state in which an information signal is recorded by the magneto-optical recording device according to the present invention will be described.

In order to record a predetermined information signal, first, an erasing operation is performed on the area of the magnetic thin film recording layer 22 provided on the magneto-optical disk 20 where the information signal is recorded. That is, the magnetic thin film recording layer 22 of the magneto-optical disk 20 is irradiated with the light beam emitted from the semiconductor laser 2 of the magneto-optical recording head device 1 through the objective lens 5, and the area where the information signal is recorded is at the Curie point. In addition to the above heating, an external magnetic field in a fixed direction is applied by the magnetic head unit 7 to make the direction of magnetization of the above-mentioned area portion a fixed direction, thereby erasing the previously recorded information signal.

Then, when recording a desired information signal, the magnetic thin film recording layer 22 of the region where the information signal of the magneto-optical disk 20 is to be recorded is irradiated with a light beam and heated to the Curie point or higher,
An external magnetic field modulated according to an information signal to be recorded is applied from the magnetic head unit 7. Then, by cooling the region, to which the external magnetic field modulated according to the information signal is applied, to the Curie point or lower, the direction of magnetization corresponding to the information signal to be recorded in the magnetic thin film recording layer 22 is coerced. Recording of the desired information signal is performed.

By the way, in the magneto-optical recording apparatus according to the present invention,
Since the soft magnetic plate 23 having high magnetic permeability and magnetic flux density is provided over the entire surface of the recording medium layer 22 provided on the disk substrate 21 of the magneto-optical disk 20, the magnetic flux B generated when the exciting coil 7b is driven is As shown by a broken line in FIG. 1, a magnetic path that penetrates the soft magnetic plate 23 is formed. Further, the tip end portion 7c of the core 7a around which the exciting coil 7b is wound is tapered so as to be directed to the focus point of the light beam focused by the objective lens 5 and applied to the magnetic thin film recording layer 22 of the magneto-optical disk 20. As a result, the magnetic flux generated from the exciting coil 7b is concentrated at the focal point of the light beam. Therefore, the vertical magnetic field generated from the exciting coil 7b can be efficiently applied to the magnetic thin film recording layer 22. Further, since the vertical magnetic field can be efficiently applied to the magnetic thin film recording layer 22, it is not necessary to supply a large current to the exciting coil 7b in order to generate the magnetic flux necessary for recording a desired information signal. Excitation coil during driving
It is possible to suppress the heat generation of 7b.

When recording an information signal on the magneto-optical disk 20 mounted on the turntable 14 and rotated, the returning light beam reflected from the magnetic thin film recording layer 22 is detected by the detector 6. As a result, the focus error signal and the tracking error signal of the light beam with respect to the magneto-optical disk 20 are detected, and the objective lens 5 is controlled in accordance with these error signals.

Further, in the above-mentioned embodiment, the example in which the magneto-optical disk 20 in which the magnetic thin film recording layer 22 is provided only on one surface of the disk substrate 21 is used has been described, but it is configured as shown in FIG. The magneto-optical disk 30 can also be used. This third
The magneto-optical disk 30 shown in the figure has two magnetic thin film layers 32, 32.
And is composed of two disk substrates 31, 31 having a magnetic thin film layer 32 formed on one surface thereof with a soft magnetic plate 33 interposed therebetween. That is, the magnetic thin film layers 32, 32
Two disk substrates with the soft magnetic plates 33 facing each other.
It is a combination of 31,31. In the magneto-optical disk 30 having the above-described structure, the turntable 14 is arranged so that the surfaces facing each other are selected so as to face the magneto-optical recording head device 1.
By mounting it on the magnetic thin film layers 32, 32, desired signals can be recorded.

Even when the magneto-optical disk 30 shown in FIG. 3 is used, the magnetic flux from the exciting coil 7b can be concentrated and applied to each of the magnetic thin film layers 32, 32 in the same manner as described above, which is efficient. Information signals can be recorded.

[Effect of device]

As described above, in the magneto-optical recording apparatus according to the present invention, the recording medium layer and the soft magnetic plate are provided on one surface side of the substrate of the magneto-optical disk, and the optical head section and the magnetic head section are provided on the other surface side of the substrate. Since the recording head device is composed of, the closed magnetic path can be formed between the magnetic head portion and the soft magnetic plate, and thus the magnetic field from the magnetic head portion is efficiently applied to the recording medium layer. be able to.

Furthermore, since the tip side of the core that constitutes the magnetic head part is tapered so as to face the focusing point of the light beam,
The magnetic field from the magnetic head portion can be concentrated on the recording medium layer, and the magnitude of the external magnetic field applied to the recording medium layer can be increased, so that a good information signal can be recorded. Since the exciting coil is provided in the tapered portion of the tip of the core, it can be separated from the means for controlling the drive of the objective lens, and the influence on the drive control mechanism of the objective lens can be reduced. Can be made smaller. Further, the core provided with the exciting coil only needs to have the tapered portion of the tip portion, and the magnetic head portion can be miniaturized.

[Brief description of drawings]

FIG. 1 is a side view showing the essential structure of a magneto-optical recording apparatus according to the present invention. FIG. 2 is a cross-sectional view of essential parts showing another example of the magneto-optical disk constituting the magneto-optical recording device according to the present invention. FIG. 3 is a schematic diagram showing a main part configuration of a conventional magneto-optical recording apparatus. 1 ... Magneto-optical recording head device 7 ... Magnetic head section 11 ... Optical head section 20,30 ... Magneto-optical disk 22,32 ... Magnetic thin film recording layer 23, 33 ... Soft magnetic thin film

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Sokatsu Fukuyama 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (56) References JP-A-57-164418 (JP, A) Sho 59-125728 (JP, U) Actually opened Sho 59-180803 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. A soft magnetic material provided over the entire surface of a recording medium layer provided on one surface of a substrate of a magneto-optical disk, and one of the substrates provided with a recording medium layer of the magneto-optical disk. Of the optical head, the optical head having an objective lens disposed on the other surface facing the surface of the recording medium, which irradiates a light beam in a focused state on the recording medium layer, and the side of the optical head on which the objective lens is provided. A core which is hollow and surrounds the objective lens, and which is formed in a taper shape such that the tip end side of the position where the objective lens is arranged is toward the focusing point of the light beam, and the tapered portion of the core. 2. A magneto-optical recording device comprising: a magneto-optical head device comprising: a magnetic head portion including a coil wound along the tapered shape.