JPH0664767B2 - Optical information recording method and optical information recording device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an optical information recording / reproducing apparatus.

[Technical background of the invention and its problems]

In recent years, an optical disk has been attracting attention as a high-density and large-capacity memory, and an information recording / reproducing apparatus using this optical disk has been put into practical use. In this device, for example, by irradiating the optical disk with a laser beam carrying image information narrowed down to a spot having a diameter of about 1 μm,
A bit having a width of 0.6 to 1 .mu.m and a length of 1 to 2 .mu.m is formed and recording is performed, and on the other hand, reproduction is performed by reflected light from the bit.

Conventionally, there are two types of recording media for forming an optical disk used in such an apparatus. One is a write-once (DRAW) recording medium in which information cannot be erased and rewritten, and the other is an erasable recording medium in which information can be erased and rewritten multiple times. Although only the write-once type recording medium has been put into practical use in the above information recording / reproducing apparatus, the erasable type recording medium is superior from the viewpoint of economical and effective use of the medium. Therefore, it is expected that a system using this recording medium will be put to practical use.

This erasable recording medium uses an amorphous alloy film composed of a rare earth element such as Gd, Tb, Dy and Ho and a transition metal such as Fe and Co as a recording film. The characteristic of this recording film is that it has an easy axis of magnetization in a direction perpendicular to the film surface, and recording / reproducing uses the direction of magnetization of each magnetic domain.

That is, in a recording film on which no recording is performed, all magnetic domains are magnetized in the same direction, and recording is performed by selectively changing the magnetization direction of a specific magnetic domain with respect to this magnetization state. Also, the reproduction is performed by reading this state. Specifically, the characteristic feature of the recording film is that it maintains a magnetically ordered state at room temperature, easily reaches the Curie point by irradiation with a laser beam, and becomes a disordered state at this time.

Therefore, the recording film is irradiated with a laser beam carrying information, the energy of the laser beam locally raises the recording film, and the coercive force of this part is reduced. At this time,
A magnetic field in a specific direction (a direction opposite to the initial magnetization direction) is applied from the outside to match the magnetization only in the local area to the specific direction. The recording film other than the one irradiated with the laser beam maintains the initial order state even when an external magnetic field is applied, and the magnetization direction does not change. This creates a pattern of magnetization in different directions during the uniform magnetization. That is, recording is made.

Next, in such recording, information is erased according to substantially the same principle, and the external magnetic field to be applied may be reversed from that during recording. For example, a laser beam is applied to the portion of the recording film on which the above-mentioned recording is made, the temperature of this portion is made to reach the Curie point vicinity, and the coercive force is reduced.
Then, a magnetic field in the opposite direction to that at the time of recording is applied, and the direction of magnetization of the relevant portion is reversed. As a result, the direction of magnetization becomes the same as before recording, and information is erased.

For such recording and erasing, the reproduction of information utilizes the rotation of the polarization plane of the laser beam. Magnetic domains are vertically arranged on the recording film surface. When a laser beam is applied to such a recording surface, the plane of polarization of the reflected beam is rotated depending on the direction of the magnetic domains. Therefore, if this rotation is detected, the direction of the magnetic domain on the recording film can be detected. This is the reproduction of information.

A disk as a memory using the recording film having the above characteristics is called a magneto-optical disk. Consider the case of rewriting to this magneto-optical disk. Since recording is made, on the recording film,
Magnetic domains in the opposite second direction are distributed in the uniform magnetic domain in the first direction. Further writing to such a recording film corresponds to changing the distribution of magnetic domains in the opposite direction during uniform magnetization. This change in the distribution of magnetization consists of recording and erasing.
It is common in terms of laser beam irradiation, but differs greatly in that the directions of the external magnetic fields applied are opposite. If this is grasped by the system, it is necessary to control the direction of the external magnetic field depending on whether recording or erasing.

More specifically, consider the case where the recording "01100" is made on the film where the recording "10001" has already been made.

The above-mentioned erase operation of "1" → "0" is performed for the first bit, and "0" → "1" for the subsequent two bits.
The above-described recording operation is required, and the next 1 bit does not need to be changed from "0" to "0". Finally, the erase operation of "1" to "0" is required again. Becomes Therefore, in the case of rewriting to the magneto-optical disk, not only the operation of recording, but also the operation of further erasing and the operation of not doing anything are required depending on the state before recording.

If such an operation is treated from the standpoint of recording accuracy, the size of the laser beam used and the irradiation position do not exactly match at the time of recording and erasing, so the magnetization state of the magnetic domains on the recording medium does not change completely. There was a fear that the information would be incorrect.

Further, considering such an operation from the viewpoint of the system, it is necessary to manage the state of the previous recording film, and three operations must be selectively executed according to this. For this reason, the system needs to manage addresses for recording and erasing, and this address management is complicated and complicated, and the control of the device is also complicated.

[Object of the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above drawbacks and provide an optical information recording apparatus which does not require complicated management and control even when rewriting information.

[Outline of Invention]

The present invention is characterized in that, in an optical information recording device using a magneto-optical disk, an erasing mode is performed before a recording mode is performed. That is, when the recording operation is instructed to the optical information recording device, the erasing operation is performed regardless of the presence or absence of the recorded pattern on the magneto-optical disk, and the recording operation is continued.

〔The invention's effect〕

According to the present invention, since erasing is always performed before recording, management of the recorded area and unrecorded area of the magneto-optical disk is completely unnecessary when rewriting to the magneto-optical disk, and the operation of the device is eliminated. Also, only a fixed erasing operation and recording operation are performed, and control is very easy.

Example of Invention

FIG. 1 is a diagram showing a schematic configuration of an optical information recording / reproducing apparatus which is an apparatus according to an embodiment of the present invention and which uses a magneto-optical disk as a recording medium. The magneto-optical disk 1 is rotationally driven by a rotary motor 3 connected to a rotary motor controller 2 so as to have a predetermined speed. Reference numeral 4a denotes a magnetic field generating element including an electromagnet, and 4b irradiates the magneto-optical disk 1 with a laser beam,
Further, it is an optical head including a laser for performing tracking, focusing control, and signal detection, a photodetector, an optical element, and the like. Hereinafter, the electromagnet 4a and the optical head 4b are collectively referred to as a magneto-optical head 4. The magneto-optical head 4 is held on a feed motor 6 connected to a feed motor controller 5, and moves to an arbitrary radial position of the magneto-optical disk 1.

The optical information recording / reproducing apparatus according to this embodiment has a recording mode and a reproducing mode, and when executing the recording / reproducing mode, a recording / reproducing mode instruction signal, a recording / reproducing sector number, and a recording / reproducing information bit number. The recording information is transferred from the external system to the magneto-optical disk device controller 8 through the interface 7, and each mode is executed by the recording mode controller 9 and the reproduction mode controller 10 in units of sectors having a certain number of information bits. To be done.

FIG. 2 shows a schematic structure of a sector which is a unit for recording and reproducing information, and shows a sync signal (1) 21 for reproducing the address number of the sector and the start position of the address number. Header (1) 22, sector address 23 of the sector, gap 24, sync signal (2) 25 for reproducing recorded information,
It is composed of a header (2) 26 indicating the start position of the record information, an information signal 27 having a fixed number of information bits, and a control signal 28 indicating the correctness of the record information. Here, sync signal (1) 21, header (1) 2
2. The sector address 23 is pre-formatted at the time of manufacturing the magneto-optical disk, or is formatted according to the system specifications before recording the information on the magneto-optical disk.

The operation of executing the recording information transferred from the external system according to the recording mode according to the present invention according to the recording mode control unit 9 will be described in detail with reference to FIG. Figure 3 (a) shows
It is a figure which shows the state before recording mode execution of the recording area on the magneto-optical disc designated by the external system. That is, it is assumed that the number of information bits transferred by the external system corresponds to the number of sectors, and recording to the sectors 33a ₁ to 33a _i is designated. 31a _{1 to} 31a _i are areas in which information relating to sector addresses of 33a ₁ to 33a _i sectors is formatted, and include the sync signal (1) 21, header (1) 22, and sector address 23 shown in FIG. Becomes, 31a ₁ to 31a
Address numbers are increasing to _i- sector. 32a _{1 to} 32a _i
Is a recording area of the information signal, which is composed of the gap 24, the synchronizing signal (2) 25, the header (2) 26, the information signal 27, and the control signal 28 shown in FIG. Further, some information bits have already been recorded in the shaded areas of 32a ₁ , 32a ₃ , ... 32a _2-i , and
No information is recorded in the blank areas of 32a ₂ , ... 32a _i , and the directions of all magnetic domains are uniformly arranged in a fixed direction defined by the system.

When the recording mode instruction signal, the recording information bit, and the recording sector are transferred by the external system, the recording mode control unit 9 sets the direction of the magnetic field generated by the electromagnet 4a as the predetermined information erasing direction. The magneto-optical head 4 is sent to the radius position of the designated sector, the sector address is reproduced and detected, and the regions 32a ₁ to 32a _i of the designated sector are sequentially erased according to the above principle regardless of the presence or absence of information. FIG. 3 (b) is a diagram showing the state of the designated recording sector after this erasing operation, which is 31b _{1 to} 31b _i and 31a _i to 31a _i , 32b _{1 to} 32b.
_i and 32a ₁ to 32a _i , 33b _{1 to} 33b _i and 33a ₁ to 33a _i indicate the same region, respectively. 32b _{1 to} 32b _i indicate a state in which magnetic domains in a region for recording information by this erasing operation are uniformly arranged in a certain direction defined by the system.

After the erasing operation is completed, the recording mode control unit 9
Reverses the direction of the magnetic field generated by the electromagnet 4a,
The magneto-optical head 4 is sent to the head sector position of the designated sector, the sector address is detected, and the data is transferred from the external system to the regions 32b ₁ to 32b _i where the magnetic domains are aligned in a certain direction by the erase operation. The information is recorded in order and the recording mode is ended. FIG. 3 (c) is a diagram showing the state of the designated recording sector after this information is recorded. 31C _{1 to} 31C _i and 31b _{1 to} 31
b _i, 32c _{i ~32c i} and _{32b 1 ~32b i, 33c 1 ~33c} i and 33b ₁ ~33b _i each represent the same region, 32c ₁ ~32c _i be newly information bits or the like is recorded Indicates.

Thus, according to this embodiment, when the recording mode is executed,
Since the erasing operation of the recording area is always performed prior to the recording of the information bit, it is possible to avoid overwriting and forgetting to erase the information bit, as well as whether or not the information is already recorded in the recording area, or whether or not the information has already been erased. It is possible to provide an easy-to-use optical information recording / reproducing apparatus that does not require management on the side of the system and is easy to manage.

Further, in this embodiment, the electromagnet 4a is used as the external magnetic field generating element for generating the magnetic field at the time of recording / erasing, but a permanent magnet capable of changing the direction of the external magnetic field by mechanical movement such as rotation or parallel movement at the time of recording / erasing is used. You may use. Further, in this embodiment, the external magnetic field generating element also has a structure in which it is moved in the radial direction by the feed motor 6, but this is also made possible by moving the external magnetic field generating element in the radial direction to a sufficient length. It can also be fixed.

[Other Embodiments of the Invention]

FIG. 4 is a diagram showing a schematic configuration of an optical information recording / reproducing apparatus according to another embodiment of the present invention. The device in this embodiment has two sets of magneto-optical heads. Magneto-optical disk 41
Is driven to rotate at a predetermined speed by the rotation motor 43 connected to the rotation motor control unit 42. 44a, 44a ′
Is a magnetic field generating element consisting of permanent magnets with opposite polarities,
Reference numerals 44b and 44b 'denote optical heads including a laser, a photodetector, and an optical element for irradiating the magneto-optical disk 41 with a laser beam and further detecting signals for tracking and focusing control. And 44b 'constitute two sets of magneto-optical heads 44 and 44', respectively. The magneto-optical heads 44 and 44 'are held on the feed motors 46 and 46' connected to the feed motor control units 45 and 45 ', respectively, and can be moved to arbitrary radial positions on the magneto-optical disk 41.

The optical information recording / reproducing apparatus according to the present embodiment has a recording mode and a reproducing mode as in the above-mentioned embodiments, and when executing the recording / reproducing mode, a recording / reproducing mode instruction signal,
The recording / reproducing sector number, the number of recording / reproducing information bits, the recording information, etc. are transferred from the external system to the magneto-optical disk device controller 48 via the interface 47, and the recording mode controller in units of sectors having a certain number of information bits. 49, the playback mode control unit 50 executes each mode.

When the recording mode instruction signal, the recording information bit, and the recording sector are transferred by the external system, the recording mode control unit
Reference numeral 49 designates the magneto-optical heads 44, 44 'which send the magneto-optical heads 44, 44' to the designated radial position of the sector, reproduce and detect the sector address, and firstly generate the magnetic field in the erasing direction in the above-described embodiment. Similarly, the direction of the magnetic domain of the information bit recording area of each designated sector is uniformly aligned in a fixed direction. Next, the sector whose information has been erased by the magneto-optical head 44 'is the rotation motor 43.
When rotated to the position of the information recording magneto-optical head 44, the information transferred from the external system is sequentially recorded by the magneto-optical head 44 in the area where magnetic domains are aligned in a certain direction by the erasing operation. .

As described above, according to this embodiment, the same effect as that of the above-described embodiment can be obtained, and by having two sets of magneto-optical heads, the time required for executing the recording mode can be reduced to about half.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, the external magnetic field generating element may be one using an electromagnet or one using a permanent magnet, and is not limited at all. It is also clear that the structure is not limited at all. Further, the magneto-optical head is not limited to the embodiment. For example, the optical head and the external magnetic field generating element may be arranged on the same surface side of the magneto-optical disk. Further, the two magneto-optical heads may be arranged on a diagonal line or may be arranged on a non-diagonal line. The difference in this arrangement may be that the two magneto-optical heads can be accessed independently, or they are provided on the same stage and the magneto-optical head preceding the rotation of the magneto-optical head is set to the erase mode. Good. In the latter case, the access of the two magneto-optical heads is always performed in conjunction.

As described above, any modifications can be made without departing from the spirit of the present invention, and such modifications are included in the present invention.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an optical information recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a sector structure of an embodiment according to the present invention, and FIG. 3 is according to the present invention. FIG. 4 is a diagram showing an operation in the recording mode of the embodiment, and FIG. 4 is a diagram showing a schematic configuration of an optical information recording / reproducing apparatus according to another embodiment of the present invention.

Claims (3)

[Claims] 1. A pre-formatted portion of the recording medium and an information signal recording area for erasing and recording an information signal by applying heat to a recording medium by irradiating a laser beam from a light source. In an optical information recording method for performing a recording area of an information signal in a sector unit consisting of a single unit or a plurality of units corresponding to the newly recorded information amount when newly recording information on the recording medium. Of all the areas consisting of sector units, the information signal recording areas of all the areas are irradiated with the laser beam to apply heat,
All of the area is erased, and subsequently to this erased area, a single laser beam from the light source is applied to the recording area of the erased information signal of the sector unit to add new information. An optical information recording method characterized by recording. 2. An information signal is recorded by irradiating one laser beam to an information signal recording area in a sector unit consisting of a pre-formatted portion of a recording medium and an information signal recording area. And an optical information recording device comprising a light irradiating means for erasing and a control means for controlling the light irradiating means, wherein the control means corresponds to the amount of information to be recorded when the information is recorded. Of all areas consisting of a single or a plurality of sector units, the information signal recording areas of all the areas are irradiated with light by the light irradiating means to erase all the areas, and then erased. An optical information recording apparatus, characterized in that information is recorded by irradiating the information irradiating area of a sector unit with light by the light irradiating means. 3. Information is recorded in an information signal recording area in a sector unit composed of a pre-formatted portion of a recording medium in which all magnetic domains are magnetized in a first direction and an information signal recording area. A single laser beam for recording and erasing data, an external magnetic field applying means for applying a magnetic field in the first direction or the second direction to the recording medium, and an external magnetic field applying means, An optical information recording apparatus comprising: a control unit that controls the light irradiation unit, wherein the control unit is configured to, when recording the information, select from a single or a plurality of sector units corresponding to the newly recorded information amount. Of all areas, information is recorded by irradiating the recording areas of the information signals of all the areas with light by the light irradiating means and applying a magnetic field in the first direction to the recording medium by the external magnetic field applying means. Then, the information is recorded in the area by irradiating light by the light irradiating means and applying a magnetic field in the second direction to the recording medium by the external magnetic field applying means. An optical information recording device characterized by being configured.