JPH05242553A - Magneto-optical disk recording device of magnetic flux modulation system - Google Patents

Abstract

(57) [Abstract] [Purpose] In a magneto-optical disk recording apparatus for recording data by applying a light beam and a magnetic field to the disk, the range in which the direction of magnetization is not determined on the recording film of the disk is made extremely small and recording is performed. An object of the present invention is to provide a device capable of accurately recording information and recording at a higher density by reducing the number of unclear contents. [Structure] A current regulator 6 is connected to a current generator 5 for energizing a magnetic head 4, and a magnetic field corresponding to a modulation signal is stronger than a magnetic field corresponding to the modulation signal for a certain period of time immediately after the direction of the magnetic field is reversed according to the modulation signal. The current regulator 6 so that a magnetic field is generated.
The energization of the current generator 5 is adjusted by. This makes it possible to form the recording areas corresponding to the recording signals so that the boundaries between them are clear.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk recording apparatus for recording information by irradiating a disk magnetized by a modulating magnetic field with a light beam, and more particularly to a technique for modulating a magnetic field.

[0002]

2. Description of the Related Art Conventionally, in an optical disk magnetic recording device, an extremely large storage capacity is realized as compared with other recording devices. This is mainly due to its recording density, and the high-density recording makes it possible to access the recording location at high speed. Further, since the recording / reproducing is performed in a non-contact manner, there is an advantage that mechanical deterioration is extremely small.

Various recording methods have been proposed and put to practical use in order to perform the above-mentioned large-capacity and non-contact recording, and one of them is a magnetic field modulation method. In this recording method, an external magnetic field modulated according to 1 or 0 of a recording signal magnetizes a recording film of a disc, and a recording portion on the recording film is magnetized.
Information is recorded by irradiating a light beam having a constant intensity.

A conventional example of a general magnetic field modulation type magneto-optical disk recording apparatus will be described with reference to FIG. The figure shows a block diagram of the recording unit of the apparatus. An optical head 3 for irradiating the recording film 1 with a light beam is arranged below a disc 2 having a recording film 1 for recording encoded information. Further, a magnetic field generator (magnetic head) 4 is provided at a position facing the optical head 3 with the disk 2 interposed therebetween. A current generator 5 is connected to the magnetic field generator 4, and an external magnetic field for magnetizing the recording film 1 is generated by energizing the coil of the magnetic head 4 from the current generator 5.

The direction of energization from the above current generator 5 is
It is controlled in accordance with a recording signal (modulation signal) of encoded information, and by controlling the energizing direction, the external magnetic field generated from the magnetic field generator 4 is modulated, that is, the direction of the magnetic field is changed. .. Further, in order to improve the quality of the reproduction signal of the information recorded on the disc 2, the maximum value of the amount of electricity supplied from the current generator 5 is kept constant.

The energization control will be described with reference to FIG. 2 (b) showing a waveform diagram of energization from the current generator 5 to the magnetic field generator 4. In the figure, at times T1 and T3, the amount of E1 is energized in order to record "1" of the encoded information on the disc 2, and conversely, at times T2 and T4, the encoded information "1" is written. In order to record "0", a current of -E1 has been applied.

[0007]

However, in the magnetic field modulation corresponding to the above recording signal, when switching the direction of the magnetic field, the magnetic field strength as shown by T0 in FIG. Occurs when is zero or very close to zero.
Therefore, on the recording film 1 of the disk 2, there are cases where the direction of magnetization is not fixed, that is, the recorded contents are unclear.

The state of the recording film 1 on which information is recorded is
It is shown in FIG. The A1 and A3 areas are shown in FIG. 2 (b).
During the T1 and T3 hours, the A2 and A4 areas
And recorded at T4 time. The A0 area is a boundary between areas having different magnetization directions, and the strength of the external magnetic field is zero or T0 that is extremely close to zero.
It is the place where the information was recorded at times. This A when playing back information
When the 0 area is read, noise may occur or wrong information may be reproduced because the direction of magnetization is unclear.

The present invention has been made in order to solve the above-mentioned problems, and in the recording film of the disc, the range where the magnetization direction is not determined is made extremely small, and the unclear portion of the recorded contents is reduced. Therefore, it is an object of the present invention to provide a magneto-optical disk recording device in which information can be accurately recorded and which enables high-density recording.

[0010]

In order to achieve the above object, a magneto-optical disk recording apparatus of the present invention comprises an optical head for irradiating a disk with a light beam, and a magnetic head for generating a magnetic field for magnetizing the disk. A current generator for energizing the magnetic head according to a modulation signal, and a current adjusting means for adjusting the energization of the current generator, and a constant value immediately after reversing the direction of the magnetic field according to the modulation signal. In time, the recording film is magnetized by a magnetic field stronger than the magnetic field corresponding to the modulated signal.

[0011]

According to the above construction, in the magneto-optical disk recording apparatus of the magnetic field modulation system which irradiates the recording film of the disk with the light beam to record information under the effect of the modulation magnetic field, the direction of the magnetic field is changed in accordance with the modulation signal. At a certain time immediately after reversing,
The current adjusting means adjusts the energization of the current generator so that a magnetic field stronger than the magnetic field corresponding to the modulated signal is generated. This makes it possible to extremely reduce the range in which the direction of magnetization is not determined on the recording film of the disc, and to form recording areas corresponding to recording signals so that the boundaries between them are clear.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magneto-optical disk recording apparatus of the present invention will be described below with reference to the drawings. FIG. 1A is a configuration diagram of a recording unit of a magnetic field modulation type magneto-optical disk recording apparatus according to this embodiment. In the figure, an optical head 3 for irradiating the recording film 1 with a light beam is arranged below a disc 2 having a recording film 1 for recording encoded information. Further, a magnetic field generator (magnetic head) is placed at a position facing the optical head 3 with the disk 2 interposed therebetween.
4 are provided. A current generator 5 is connected to the magnetic field generator 4, and the current generator 5 further includes
A current regulator 6 for regulating the current is connected.

The function of the current regulator 6 will be described. The direction of the current passed from the current generator 5 to the magnetic field generator 4 to form the external magnetic field is sequentially switched according to the recording signal (modulation signal) of encoded information, and The maximum value of the magnitude of the current is usually constant. By the way, when the energizing direction is switched, a state where the magnetic field strength is zero or very close to zero occurs, and the recording film 1
In the above, there is a portion where the recorded content, that is, the magnetization direction does not correspond to either 1 or 0 of the encoded information. Therefore, the current regulator 6 is provided, and the current regulator 6 adjusts the current generator 5 so that the recording film 1 is appropriately magnetized.

FIG. 2A is a waveform diagram of the current generated from the current generator 5 in this embodiment. Figure 2 above
In the conventional example shown in (b), T1, T
The energizing direction is sequentially switched at each time of 2, T3, T4, and the magnitude of the current is E1 or -E.
It was constant at 1 level. On the other hand, in this embodiment,
As shown in FIG. 2A, a certain period of time immediately after reversing the energization direction to the magnetic field generator 4, that is, T1 in FIG.
In 1, T12, T13, T14, a current (adjustment current) of, for example, E2, −E2 level, which is larger than that corresponding to the modulation signal, is supplied from the current generator 5 to the magnetic field generator 4. There is. Since an external magnetic field is generated according to this energization, the adjustment time T11, T immediately after the magnetic field modulation
In 12 and so on, a magnetic field stronger than that required by the modulation signal is formed.

FIG. 3A is a plan view showing a state of the recording film 1 of the disc 2 on which information is recorded in this embodiment. Areas A1 and A3 are T1 and T3 in FIG.
The A2 and A4 areas are the locations recorded at the same T2 and T4 hours, respectively. In the conventional example shown in FIG. 3B, a boundary portion A0 of areas having different magnetization directions is used.
Then, the magnetization direction was unclear, but in this embodiment,
As described above, T11, T immediately after reversing the energizing direction
By passing an adjusting current through T12, T13, and T14, the magnetization direction is clear even in the A0 area. As a result, the area where the magnetization direction is not determined can be made extremely small on the recording film of the disc.

The magnitudes of the adjustment currents E2 and -E2 and the lengths of the adjustment times T1, T2, etc. are appropriate in consideration of the scale and performance of the magnetic field generator installed in the apparatus, the type of recording film, and the like. You can set any value.

[0017]

As described above, according to the present invention, a current larger than the current corresponding to the modulation signal is supplied for a certain period of time immediately after the direction of energization to the magnetic field generator is reversed according to the modulation signal. However, since the external magnetic field acting on the recording film of the disc is adjusted so that a magnetic field stronger than the magnetic field according to the modulation signal is generated, the range in which the direction of magnetization is not determined on the recording film of the disc is made extremely small, It is possible to form the recording areas corresponding to the recording signals so that the boundaries between them are clear. As a result, a magneto-optical disk recording apparatus in which information can be accurately recorded and which can be recorded at higher density is realized.

[Brief description of drawings]

FIG. 1A is a configuration diagram of a recording unit of a magneto-optical disk recording apparatus according to an embodiment of the present invention. FIG. 1B is a configuration diagram of a recording unit of a conventional magneto-optical disk recording device.

FIG. 2 is a waveform diagram of energization from a current generator to a magnetic field generator.

FIG. 3 is a plan view showing a state of a recording film of a disc on which information is recorded.

[Explanation of symbols]

 1 recording film 2 disk 4 magnetic field generator 5 current generator 6 current regulator

Claims (1)

[Claims] 1. An optical head for irradiating a disk with a light beam, a magnetic head for generating a magnetic field for magnetizing the disk, and a current generator for energizing the magnetic head according to a modulation signal are provided. In a magnetic field modulation type magneto-optical disk device that modulates according to a signal and irradiates the recording beam of the disk with the light beam to record information under the action of the modulation magnetic field, current adjustment for adjusting energization of the current generator Means for irradiating the recording film with a magnetic field stronger than the magnetic field corresponding to the modulation signal for a certain period of time immediately after the direction of the magnetic field is inverted according to the modulation signal. Magnetic disk device.