JP2783774B2 - Optical information recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus. [0002] In recent years, as high-density, large-capacity memories,
Optical disks are receiving attention, and information recording / reproducing apparatuses using the optical disks have been put to practical use. In this device,
For example, by irradiating an optical disc with a laser beam carrying image information focused on a spot having a diameter of about 1 μm, a bit having a width of about 0.6 to 1 μm and a length of about 1 to 2 μm is formed and recorded. The reproduction is performed by the reflected light. Conventionally, there have been 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 a plurality of times. In the above information recording / reproducing apparatus, only those using a write-once type recording medium have been put to practical use, but from the viewpoint of economical and effective use of the medium, an erasable type recording medium is superior. Therefore, practical use of a system using this recording medium is expected. [0004] This erasable recording medium is, for example, Gd,
An amorphous alloy film composed of a rare earth such as Tb, Dy, Ho and the like and a transition metal such as Fe and Co is used as a recording film. The feature of this recording film is that it has an easy axis of magnetization in a direction perpendicular to the film surface, and recording and reproduction use 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. By selectively changing the magnetization direction of a specific magnetic domain with respect to this magnetization state, Recording is performed, and reproduction is performed by reading this state. More specifically, the feature of the above-described recording film is that it maintains a magnetically ordered state at room temperature, easily reaches the vicinity of the Curie point by irradiation with a laser beam, and becomes disordered at this time. Accordingly, a laser beam carrying information is irradiated onto the recording film, the recording film is locally raised by the energy of the laser beam, and the coercive force of this portion 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 of only the local part to the specific direction. The recording film other than the one irradiated with the laser beam maintains its initial order state and does not change its magnetization direction even when an external magnetic field acts. Thereby, a pattern of magnetization in different directions is formed during magnetization of magnetization in a uniform direction. That is, recording is performed. Next, information is erased from such a recording according to substantially the same principle, and the applied external magnetic field may be reversed from that at the time of recording. For example, irradiating a laser beam to the portion of the recording film on which the above-described recording was performed,
The temperature of this portion is made to reach near the Curie point, and the coercive force is reduced. Then, a magnetic field in a direction opposite to that in the recording is applied, and the direction of the magnetization of the portion is reversed. As a result, the direction of magnetization becomes the same as before recording, and information is erased. In contrast to such recording and erasing, information is reproduced by utilizing the rotation of the plane of polarization of a laser beam. Magnetic domains are vertically arranged on the recording film surface, and when such a recording surface is irradiated with a laser beam, the plane of polarization of the reflected beam is rotated in the direction of the magnetic domains. Therefore, if this rotation is detected, the direction of the magnetic domain on the recording film is detected. this is,
Reproduction of information. A disk as a memory using a recording film having the above characteristics is called a magneto-optical disk. Let us consider a case where rewriting is performed on the magneto-optical disk. Since recording is being performed, magnetic domains in the second direction opposite to the magnetic domain in the uniform first direction are distributed on the recording film. Further writing on such a recording film corresponds to changing the distribution of magnetic domains in the opposite direction in uniform magnetization. This change in the distribution of magnetization is made up of recording and erasing, but they are largely different in that the directions of the applied external magnetic field are opposite, although they are common in terms of laser beam irradiation. If this is captured by the system, it is necessary to control the direction of the external magnetic field depending on whether recording or erasing. [0010] More specifically, consider a case where a recording of "01100" is made on a film on which a recording of "10001" has already been made. For the first bit, [1] → [0]
The above-described erasing operation requires the above-mentioned recording operation of “0” → “1” for the following two bits, and the next one bit is “0” → “0”. It is not necessary to perform this operation, and an erasing operation of “1” → “0” is finally required again. Therefore, in the case of rewriting to the magneto-optical disk, not only an operation of recording but also an operation of erasing and an operation of not performing anything are required depending on a state before recording. If such an operation is handled from the standpoint of recording accuracy, the size and irradiation position of the laser beam used do not exactly match at the time of recording and erasure, so that the magnetization state of the magnetic domain on the recording medium is completely changed. Otherwise, there was a risk of information errors. 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 selected and executed accordingly. . For this reason, the system needs to manage addresses for recording and erasing,
In addition, the address management is complicated and complicated, and the control of the apparatus is also complicated. Conventionally, in the case of rewriting on a magneto-optical disk, not only the operation of recording but also the operation of erasing further depending on the state before recording, and nothing is performed. Operation is required. If such an operation is treated from the standpoint of recording accuracy, the size and irradiation position of the laser beam used do not exactly match at the time of recording and erasure, so that the magnetization state of the magnetic domain on the recording medium is completely changed. Otherwise, there was a risk of information errors. Further, considering such an operation from the standpoint of the system, it is necessary to manage the state of the previous recording film, and three operations must be selectively executed accordingly. . For this reason, the system needs to manage addresses for recording and erasing,
In addition, there is a problem that the address management is complicated and complicated, and the control of the apparatus is also complicated. An object of the present invention is to provide an optical information recording apparatus which eliminates the above disadvantages and does not require complicated management and control when rewriting information on a magneto-optical disk. The present invention is characterized in that, in an optical information recording apparatus using a magneto-optical disk, an erase mode is performed before a recording mode is performed. That is, when a recording operation is instructed to the optical information recording apparatus, an erasing operation is performed irrespective of the presence / absence of a recorded pattern on the magneto-optical disk, and the operation shifts to a recording operation. FIG. 1 is a diagram showing a schematic configuration of an optical information recording / reproducing apparatus using a magneto-optical disk as a recording medium, which is an apparatus according to an embodiment of the present invention. Magneto-optical disk 1
Is driven to rotate at a predetermined speed by a rotation motor 3 connected to the rotation motor control unit 2. 4a is a magnetic field generating element composed of an electromagnet. 4b is an optical head composed of a laser for irradiating a laser beam onto the magneto-optical disk 1 and further 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 control unit 5 and moves to an arbitrary radial position on the magneto-optical disk 1. The optical information recording / reproducing apparatus in this embodiment has a recording mode and a reproducing mode. When executing the recording / reproducing mode, a recording / reproducing mode instruction signal, a recording / reproducing sector number, and a recording / reproducing mode are used. The number of information bits, recording information, and the like are transferred from the external system to the magneto-optical disk drive control unit 8 via the interface 7, and the recording mode control unit 9 and the reproduction mode control unit 10 perform each operation in units of sectors having a fixed number of information bits. The mode is executed. FIG. 2 shows a schematic structure of a sector which is a unit when recording and reproducing information. A synchronizing signal (1) 21 for reproducing an address number of the sector, a starting position of the address number are shown. (1) 22, indicating the sector address of the sector
23, gap 24, synchronization signal for reproducing recorded information
(2) 25, (2) 26 indicating the start position of the recording information, an information signal 27 having a fixed number of information bits, and a control signal 28 indicating whether the recording information is correct or not. Here, synchronization signal (1) 21, header (1) 22,
The sector address 23 is pre-formatted at the time of manufacturing the magneto-optical disk, or is formatted according to the system specifications prior to recording information on the magneto-optical disk. The operation of executing the recording information transferred from the above-described external system in accordance with the recording mode according to the present invention in accordance with the recording mode control unit 9 will be described in detail with reference to FIG. FIG.
(a) is a diagram showing a state of a recording area on a magneto-optical disk designated by an external system before a recording mode is executed. That is, it is assumed that the number of information bits transferred by the external system is the number of sectors corresponding to _i sectors, and that recording to 33a ₁ to 33a _i sectors is specified. 31a _{1 to} 31a _i
33a ₁ ~33a _i information on the sector address of the sector is in the region being formatted, FIG. 2 synchronization signal shown in (1) 21, a header (1) 22 consists of a sector address 23, 31a _i from 31a ₁ The address number is increasing to the sector. 32a _{1 to} 32a _i are information signal recording areas,
The gap 24, the synchronization signal (2) 25, and the header shown in FIG.
(2) Consists of 26, information signal 27, and control signal 28. 32a ₁ ,
32a _3, ... already some kind of information bits is recorded in the region indicated by hatched portions 32a _2-i, also 32a _2, ... no record of what such information in a region indicated with a blank 32a _i, all Are uniformly aligned in a fixed direction determined by the system. When a recording mode instruction signal, recording information bits, and a recording sector are transferred by an external system,
The recording mode control unit 9 sets the direction of the magnetic field generated by the electromagnet 4a to the direction of the predetermined information erasure, sends the magneto-optical head 4 to the radius position of the specified sector, and reproduces and detects the sector address. In accordance with the above principle, the areas 32a ₁ to 32a _i of the sector are sequentially erased regardless of the presence or absence of information. 3 (b) is a diagram showing a state of the specified recording sector after the erase operation, and 31b ₁ ~31b _{i
31a i ~31a i, 32b 1 ~32b} i and 32a ₁ ~32a _i, 33
b ₁ ~33b _i and 33a ₁ ~33a _i denotes a same area. 32b ₁ ~32b _i indicates a state in which uniformly be e it in a certain direction that the magnetic domain is defined in the system area for recording information from the erase operation. After the erasing operation is completed, the recording mode control section 9 reverses the direction of the magnetic field generated by the electromagnet 4a and sends the magneto-optical head 4 to the head sector position of the designated sector. 32b ₁ to 32b in which the magnetic domains are aligned in a certain direction by the erase operation
_The information transferred from the external system is sequentially recorded in the area _i , and the recording mode ends. FIG. 3 (c), a diagram showing a state of the specified recording sector after the information recording, 31C ₁ ~31C
_i and _{31b 1 ~31b i, 32c i ~32c} i and 32b ₁ ~32
b _i, 33c ₁ ~33c _i and 33b ₁ ~33b _i each represent the same region, 32C ₁ ~32c _i indicates that new information bits, etc. are recorded. As described above, according to this embodiment, when the recording mode is executed, the erasing operation of the recording area is always performed prior to the recording of the information bit. This eliminates the need for the system to manage whether or not information has already been recorded or has been erased, and provides an easy-to-use optical information recording / reproducing apparatus with easy system management. In this embodiment, the electromagnet 4a is used as an external magnetic field generating element for generating a magnetic field during recording / erasing. However, a permanent magnet whose direction of the external magnetic field can be changed by mechanical movement such as rotation or translation during recording / erasing is used. May be used. In this embodiment, the external magnetic field generating element is also moved in the radial direction by the feed motor 6, but this is also achieved by sufficiently increasing the length of the external magnetic field generating element in the radial direction to prevent the external magnetic field generating element from moving in the radial direction. It can also be fixed. (Other Embodiment 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. The magneto-optical disk 41 is driven to rotate at a predetermined speed by a rotation motor 43 connected to a rotation motor control unit. 44a and 44a 'are magnetic field generating elements made of permanent magnets having opposite polarities, and 44b and 44b' are lasers for irradiating a laser beam on the magneto-optical disk 41 and further detecting signals for tracking and focusing control. An optical head consisting of photodetectors, optical elements, etc., 44a, 44b, 44
a 'and 44b', two sets of magneto-optical heads 44 and 4 respectively.
4 '. Magneto-optical heads 44 and 44 'are respectively provided with feed motors 46 and 46' connected to feed motor control units 45 and 45 '.
It can be moved to an arbitrary radial position of the magneto-optical disk 41 while being held above. The optical information recording / reproducing apparatus according to the present embodiment has a recording mode and a reproducing mode as in the above-described embodiment.
When executing the recording / reproducing mode, a recording / reproducing mode instruction signal, a recording / reproducing sector number, a recording / reproducing information bit number, recording information, and the like are transmitted from an external system to the magneto-optical disk device controller 48 via an interface 47. Transferred,
Each mode is executed by the recording mode control unit 49 and the reproduction mode control unit 50 in a unit of a sector having a fixed number of information bits. When the external system transfers the recording mode instruction signal, the recording information bit, and the recording sector, the recording mode control unit 49 sends the magneto-optical head 44, 44 'to the radius position of the specified sector, and sends the sector address. Playback detected, 1st
The direction of the magnetic domain of the information bit recording area of each designated sector is uniformly aligned in a certain direction by the magneto-optical head 44 'which generates a magnetic field in the erasing direction. Next, when the sector from which information has been erased by the magneto-optical head 44 'is rotated by the rotary motor 43 and reaches the position of the magneto-optical head 44 for information recording, the information transferred from the external system is sequentially processed by the magneto-optical head 44. Are recorded in the area where the magnetic domains are aligned in a certain direction by the erasing operation. As described above, according to this embodiment, the same effects as those of the above-described embodiment can be obtained. Further, by having two sets of magneto-optical heads, the time required for executing the recording mode can be reduced to approximately half. Can be. 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 use an electromagnet or 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 side of the magneto-optical disk. Further, in order to arrange the two magneto-optical heads, they may be arranged diagonally or non-diagonally. This difference in arrangement may be such that the two magneto-optical heads may be independently accessible, or may be provided on the same stage, and the magneto-optical head preceding the rotation of the magneto-optical head may be set to the erase mode. Is also good. In the latter case, the access of the two magneto-optical heads is constantly performed in conjunction with each other. As described above, any modifications can be made without departing from the spirit of the present invention.
This is included in the present invention. According to the present invention, since erasure is always performed before recording, management of the recorded area and unrecorded area of the magneto-optical disk is completely performed when rewriting is performed on the magneto-optical disk. It becomes unnecessary, and the operation of the device is also constant erase operation,
Only the recording operation is performed, and the control becomes very easy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a schematic configuration of an optical information recording / reproducing apparatus according to one embodiment of the present invention. FIG. 2 is a diagram showing a sector structure according to an embodiment of the present invention. FIG. 3 is a diagram showing an operation in a recording mode of the embodiment according to the present 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. [Description of Signs] 1 ... Magneto-optical disk 4 ... Magneto-optical head

Claims (1)

(57) [Claims] Light for irradiating one laser beam for recording and erasing the information in the information recording area in the sector unit composed of the pre-formatted portion of the recording medium and the information recording area Irradiating means; external magnetic field applying means for applying a magnetic field in a first direction or a second direction to the recording medium; and optical information recording comprising control means for controlling the external magnetic field applying means and the light irradiating means. An apparatus, comprising: a recording area for recording information of all areas of all areas composed of a single or a plurality of sector units corresponding to an amount of information to be newly recorded when recording the information. After erasing the information signal by irradiating light to the recording medium with the light irradiating means and applying a magnetic field in the first direction to the recording medium by the external magnetic field applying means, According irradiation of light, and the external magnetic field applying means according to a second direction the optical information recording apparatus characterized by being configured to perform recording of information by the application of magnetic field to the recording medium.