JP3025561B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus using an optical disk capable of recording and reproducing information on both sides.
In particular, the present invention relates to an optical disk device capable of simultaneously recording and reproducing data on both sides.

[0002]

2. Description of the Related Art A conventional optical disk device generally has an optical head mounted on only one side of a disk, as described in, for example, Japanese Patent Application Laid-Open No. 2-281424 (hereinafter referred to as "Document 1"). In the case of recording / reproducing on the back surface of the optical disk, it is necessary to once take the disk out of the apparatus and turn it over (invert). Further, for example, Japanese Patent Application Laid-Open No. Sho 63-24
As described in Japanese Patent No. 4315 (hereinafter referred to as "Document 2"), there is also known an apparatus in which heads are provided on both sides of a disc and recording and reproduction are performed on both sides while the optical disc is attached to the apparatus. When the back side is accessed after the recording / reproducing operation is completed, it is necessary to stop the rotation of the disk and rotate the disk in the opposite direction.

As described in, for example, JP-A-59-38948 (hereinafter referred to as “Document 3”),
It is known that the spiral shape of the front and back tracks is reversed.

Further, in recent years, for example, as described in “Nikkei Electronics, No. 506, August 6, 1990” (pages 173 to 180) (hereinafter referred to as “Document 4”), When initializing (initial erasing) a recording medium using a magneto-optical recording medium in which an auxiliary layer having a high Curie point temperature and a low coercive force and a recording layer having a relatively low Curie point temperature and a high coercive force are stacked. In the first step, a magnetic field having a strength between the holding forces of the two layers is applied in a first direction perpendicular to the recording medium surface, for example, in a direction from the auxiliary layer to the recording layer, using an initialization magnet. When recording data on a recording medium by uniformly magnetizing in the direction of the first direction, a bias magnet that gives a relatively low bias magnetic field in a direction opposite to the first magnetization direction is used. Modulated by low-level light Using a laser beam that heats above the Curie point and heats the auxiliary layer below the Curie point, the magnetization of the auxiliary layer is held at low level light and inverted with high level light, and the exchange coupling force acts between the two layers when the medium is cooled. There is known a two-layer film type magneto-optical recording method using a light intensity modulation method in which the recording layer is transferred in the magnetization direction of the auxiliary layer.

[0005]

In the prior arts of the above-mentioned Documents 1 and 2, an optical disk can be recorded / reproduced only from one side of the optical disk. To record / reproduce the other side of the optical disk, the disk must be taken out and reinserted, or An operation to reverse the motor is required, and when viewed from a host device, the capacity of both sides (double of one side) because both sides of the disk cannot be recorded and reproduced simultaneously.
However, the transfer speed to the host device is also low. Further, in the prior art apparatuses of Documents 2 and 3, when a disk recorded by the apparatus is inserted upside down into the apparatus, there is no problem because there is an information signal for identifying the front and back of the disk surface. When trying to record / reproduce a disc recorded by the device of the reference 3 by the device of the reference 3,
It was not possible to identify the front and back sides, the direction of the spiral, or the recording direction (rotation direction), and therefore, it was not possible to record / reproduce what was recorded in Documents 1 and 2 using the device in Document 3.

[0006] However, none of the above-mentioned documents 1 to 3 considers any attempt to enable recording and reproduction between such devices.

Further, in the magneto-optical recording method of the light intensity modulation method having a two-layer film according to Document 4, if an attempt is made to apply the double-sided recording method, it is necessary to initialize the auxiliary layers on both sides, and the optical disks are formed on both sides of the disk. Not only do you have a head,
It is also necessary to consider the initialization and mounting of the recording magnet and the magnetization direction.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to obtain an apparatus capable of simultaneously recording or reproducing the front and rear surfaces of a disk so that the capacity of both sides of the disk can be utilized and the transfer speed can be increased when viewed from a host device. It is another object of the present invention to provide an optical disk apparatus which can reproduce a conventional disk which is recorded and reproduced one by one.

Another object of the present invention is to provide an optical disk apparatus using a two-layer type optical intensity modulation type magneto-optical disk recording medium, in which a separate recording head is provided on the front and back and a common initial magnetization head (initialization magnet) is provided on the front and back. ) To provide an optical disk device capable of recording information on both sides simultaneously.

[0010]

In order to achieve the above object, the present invention uses a first optical disk recording medium having a recording surface of a recording track format in the opposite direction on the front and back, and simultaneously records and reproduces both recording surfaces. In an optical disk device having one set of optical heads, each optical disk recording medium is used by using a second optical disk recording medium having a recording surface on one side or a third optical disk recording medium having a recording track format of the same direction on both sides. Each medium has a front and back identification mark for identifying the front and back, and one of the optical disc recording media has a medium identification mark for identifying the third optical disc recording medium and the recording medium of the first or second optical disc. Sometimes, by detecting the front / back identification mark and the medium identification mark, the front / back insertion state of the optical disc and recording are performed. Rack format (to determine the inserted state and format) in accordance with the configured to switch the disk drive unit and the recording reproducing unit. Here, the "recording track format" refers to the recording direction of the track in the case of a concentric track, that is, the direction of relative rotation of the head with respect to the disk, and the spiral track further includes the direction of the spiral. The terms "reverse direction on the front and back" and "same direction on the front and back" refer to the direction in which the recording surface on the front side is viewed from the front side and the recording surface on the back side is viewed from the back side.

A pair of magneto-optical heads for recording signals on both recording surfaces simultaneously using a two-layer type light intensity modulation type magneto-optical disk recording medium having recording surfaces of recording track formats in opposite directions on both sides. Wherein the magneto-optical head comprises a separate recording head for recording a signal on each of the front and back recording surfaces, and a single initialization magnet for applying a unidirectional initial magnetizing magnetic field to both the front and back recording surfaces. The direction of the initial magnetization and the polarity of the recording signal are set to be opposite to each other on the front and back recording surfaces as viewed from each surface. Further, the optical disc apparatus has a two-layer type light intensity modulation in which the recording surface of the recording track format of the opposite direction is provided on the front and back sides, and the initial magnetization direction and the polarity of the recording signal are reversed on the recording surfaces of the front and back sides as viewed from each surface. In addition to the first magneto-optical disk recording medium of the system, the second layer of the two-layer type light intensity modulation system having a recording surface on one side
Or a third magneto-optical disk recording medium having a recording surface of a recording track format in the same direction on the front and rear sides and having the same initial magnetization direction and the polarity of the recording signal on the front and rear recording surfaces when viewed from each surface. The first to third magneto-optical disk recording media each have a front and back identification mark for identifying the front and back, and the third magneto-optical disk is provided on any one of the optical disc recording media. A medium identification mark for identifying the disk recording medium and the first or second magneto-optical disk;
By detecting the front / back identification mark and the medium identification mark, the front / back insertion state, recording track format, initial magnetization direction and recording signal polarity of the magneto-optical disk are determined, and the insertion state, format, and initial magnetization direction are determined. , And the polarity). In this case, the conventional disc front / back discriminating means and the disc discriminating medium medium discriminating means may be combined. Instead, a signal indicating the recording magnetization direction or the initial magnetization direction is applied to the disc recording medium for each of the front and back faces. If it is inserted, it is possible to identify the front and back surfaces and to identify the third magneto-optical recording medium and the other magneto-optical recording media only by detecting each recording magnetization direction or initial magnetization direction on both front and rear surfaces.

[0012]

The operation based on the above configuration will be described.

According to the present invention, since the recording track format on the front and rear surfaces of the optical disk is reversed, when the optical disk is rotated in one direction, both the front and rear surfaces appear to have the same format on the optical disk device and are simultaneously recorded / reproduced. Can be. In addition, the optical disc or the cartridge is provided with a function of identifying whether the optical disc is the first, second, or third format optical disc, and a function of discriminating the front and back of each type of optical disc. , The optical disk of the third type can be automatically switched to the disk rotation direction and the recording / reproducing means adapted to the third type, and both can be reproduced.

Regardless of the type of optical disk, when the disk is inserted upside down during recording and reproduction, the correct disc rotation direction and the recording / reproducing circuit that match the disc are determined and automatically switched. In any case, recording and reproduction can be performed without changing the disc.

According to the present invention, when a magneto-optical disk recording medium of a two-layer film single-light intensity modulation system is used, a single initialization magnet which applies a unidirectional initial magnetization magnetic field to both front and back surfaces. Is provided, and the polarity of the recording signal is set to the opposite polarity on the front and back, so that the signal can be simultaneously recorded on the front and back with a simple configuration. In this case, by setting the initial magnetization direction to the disk format, the type of the disk at the time of loading the disk (the initial magnetization direction and the recording magnetization direction in the front / back reverse recording format are opposite to the initial magnetization direction and the initial magnetization direction in the front / back same direction recording format). The recording magnetization direction is the same on the front and back, or the recording surface has only one recording surface in one recording format), and the insertion state of the front and back can be determined, and the rotation direction of the disc, signal polarity, reproduction The circuit is automatically switched, and recording and reproduction can be performed under any conditions.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of an optical disk device according to an embodiment of the present invention, showing a state where a disk 4 is set at a recording / reproducing position. The optical disk apparatus 1 includes optical heads 2 and 3 provided on both sides of the disk 4, a drive motor 9 for the disk 4, a disk (cartridge) holding / loading mechanism, a loading mechanism 10 for the upper side head 2,
Cartridge identification sensor 6, optical head support base 1
1 and a control circuit 8. Usually 5 inches I
The optical disk 4 of the SO standard enters the cartridge 5 and is used.

Next, the operation will be described. The cartridge 5 containing the disk 4 is put into the optical disk device 1 by an operator. When it is detected that the cartridge 5 has entered the holder 7 of the loading mechanism, the loading mechanism 7 moves down to the recording / reproducing position. The upper head 2 is lowered by the loading mechanism 10 in synchronization with this operation. When it is detected that the cartridge 5 is set at a predetermined position, the loading mechanism stops. At this time, the upper and lower optical heads 2 and 3 are positioned with respect to the disk 4, respectively. When the loading mechanisms 7 and 10 stop, the motor 9
Rotates clockwise (hereinafter abbreviated as cw) when viewed from above. When it is detected that a predetermined number of rotations has been reached, the laser of the optical heads 2 and 3 emits light, and recording and reproduction can be performed.

FIG. 2 shows a track format (recording groove) 12 of the disk 4. In this example, the lower surface (hereinafter, this surface is referred to as A surface in the following description) has a clockwise (clockwise) format when viewed from this surface side (lower side). In the case of a 5-inch disk, track 0 is on the inner circumference side and the rotation direction 14 of the disk is counterclockwise (counterclockwise), so that the light spot 13 can be accessed from the beginning (inner circumference) of the track. In the case of the upper surface (hereinafter referred to as surface B), the format 12 is counterclockwise as viewed from this surface, and the rotation direction 14 of the disk is clockwise. Week). In this embodiment, since the upper and lower optical heads 2 and 3 can be accessed independently of each other, recording and reproduction can be performed simultaneously on both sides, and a single-sided head device (even if the recording surface has two sides, the capacity for continuous transfer is only one side). The recording capacity on-line viewed from the host device is doubled, and the transfer speed is also improved.

In the illustrated example, the format 12 is spiral, but even in the case of concentric shapes, the recording format (recording direction) on the upper and lower surfaces may be reversed.

Next, A / B double-side recording was performed using a device having a head on one side. The case where an optical disk of the current ISO (International Standards Organization) format is inserted will be described. FIG. 3 shows the appearance of the current ISO standard cartridge 5. The cartridge 5 has, for example, holes 15 and 15a as marks for identifying the cartridge. This mark 15, 1
5a indicates, in the conventional ISO standard, whether (1) a rewritable disk such as a magneto-optical disk or a non-rewritable disk, or (2) a disk having a double-sided recording surface or a disk having only one surface. It is identified by the presence or absence of a hole. In the case of an ISO standard cartridge,
A / B (front and back) identification marks have notches (not shown).

In this embodiment, the disk is further formed by operating the heads on the front and back surfaces simultaneously to form reverse spiral (reverse format) tracks on the front and back surfaces, or other disks (the single-sided head disk inverted type disclosed in Reference 1). Disc 15) is added as an identification mark for discriminating a disc recorded in the same direction by the device of the above-mentioned type or a disc having a spiral track formed in the same direction by the device of the double-sided head reverse rotation drive type described in Reference 2. (The hole 15b is made in the reverse spiral type disc, and the hole 15b is not made in other types of discs). Thus, when the cartridge is inserted or loaded into the apparatus, it is possible to distinguish between a reverse spiral type (reverse format type) disk and a same direction spiral type (same direction format type) disk. The format direction (spiral direction) 12 of the disk 4 is determined by detecting the reverse spiral (reverse format) / spiral (same direction format) identification mark and the A / B surface (front / rear surface) identification mark. it can. As a result, the rotation direction of the motor 9 can be automatically switched to cw or ccw in accordance with the direction of the format 12, and can be used for either double-sided simultaneous recording / reproduction (reverse format) or single-sided recording / reproduction (same-direction format). The corresponding disk 4 can also be recorded and reproduced. FIG. 4 shows the motor rotation direction in the case of this embodiment. In FIG. 4, “A side” indicates a case where the cartridge is inserted with the A side down (normally), “B side” indicates a case where the cartridge is inserted with the B side down (reverse), and “reverse format” indicates In the case of reproducing a disk of a format formed (recorded) according to the embodiment of FIG. 2, “simultaneous format” indicates a case of reproducing a disk of a format formed (recorded) according to the example of Document 1 or 2 from the lower surface. Further, the rotation directions of cw, ccw, etc. are shown in a state viewed from above.

The identification mark of this double-sided (reverse format) / single-sided head (unidirectional format) disc is as follows.
The information may be recorded at the initial position of the head 3 in the disk 4 instead of the cartridge 5. Further, the identification mark is not limited to the hole, and various means capable of detecting mechanically, electrically, or optically can be applied. Further, a mark for identifying a recording direction (format) can be provided for each recording surface of the cartridge or the disk.

Next, referring to FIGS. 5 and 6, a description will be given of a case where the optical disk device is a light intensity modulation type magneto-optical disk device having a two-layer film. In the case of a two-layer film, the disc 4 has a recording layer (A side 19, B side 18) and an auxiliary layer (A side 17, B side 16). FIG. 6 shows a conventional example in which the optical head 3 is provided on one side. In this embodiment, the optical heads 2 and 3 are provided on both sides of the disk, and the initialization magnet 20 of the auxiliary layer is provided.
FIG. 5 shows a case where is held on one side. 5 and 6, 2
0 is an initialization magnet, 21 is an initial magnetization direction, 22 is an auxiliary layer magnetization force, 23 is an A-side recording magnet, 24 is a magnetization direction by an A-side recording magnet, 25 is a B-side recording magnet, and 26 is a B-side recording magnet. The magnetization direction.
In the case of the conventional example (Document 4), as shown in FIG.
(Relatively high Curie point temperature and low coercive force) were initialized (erased) in the magnetization direction upward to the head, and the magnetization direction of the recording magnet 23 was downward. This is A / B
Both sides are the same (since the disc is turned over and one-sided recording is performed similarly).

On the other hand, in the embodiment of the present invention, as shown in FIG. 5, the recording heads 2 and 3 are provided on both sides of the disk. The initialization and recording are performed simultaneously on both sides. Accordingly, the initialization magnet 20 on one side (A side) also causes the B side to have an upward initial magnetization direction. For this reason, the magnetization directions 26, 2 of the upper and lower recording magnets 2, 3 are set.
4 is reversed. Therefore, when recording and reproduction are performed by the upper and lower heads 2 and 3, it is necessary to reverse the polarities of the recording signals "0" and "1". If the upper side is provided with an initialization magnet having the same magnetization direction as the one-sided head, it is not necessary to reverse the polarity of the signal.However, when recording, lower the one-sided initialization magnet to a position where there is no influence. It is necessary to take measures to prevent the magnetic field from the initially magnetized magnet from affecting the magnetic layer on the other side, and it is extremely difficult to take such measures in practice. On the other hand, according to the present embodiment, it is not necessary to take such measures, and simultaneous recording and reproduction on both sides can be easily performed.

Next, a case where the disk used (recorded) in the one-sided head apparatus as shown in FIG. 6 is used in the apparatus having the double-sided head according to the present embodiment (FIG. 5) will be described. In the case of a disk used in a double-sided head, information indicating the recorded magnetization direction (signal polarity) is put in the disk format on the disk. For example, a method such as adding a mark such as a hole to a disc or cartridge having a reversal of the polarity of a recording signal, or writing information indicating the polarity of a recording signal at the beginning of a track on a disc. A method is conceivable. If the format is not this (mark), it can be determined that the format has a conventional one-sided head. The polarity of the recording signal can be detected and determined by a combination of this and the determination of the A / B surface (whether the surface is the front surface or the back surface), and thereby the recording signal can be reproduced. Next, a case where a double-sided head (reverse format type) disk is inserted in reverse will be described. In the case of a double-sided head disk, since the signal polarity of the disk is in the disk format, the signal can be reproduced by reading this signal and automatically switching the signal polarity circuit.

Also, in this embodiment, a 5-in ISO optical disk cartridge is used, and one optical head is disposed on each of the upper and lower surfaces of the disk. However, in order to further increase the transfer speed, the head access is required. Additional holes are drilled in the cartridge, and the optical heads are
A method of arranging individual pieces is also conceivable.

[0028]

As described above in detail, according to the present invention, by reversing the recording track format on both sides of the optical disk, both sides can be simultaneously recorded and reproduced by the optical heads on both sides. The observed online capacity and transfer speed can be doubled compared to the method of recording and reproducing one side at a time. This double-sided simultaneous recording / reproducing type optical disk, the conventional optical disk having only one side recording surface, and the recording surface on the front and back sides can be changed to one side. A mark for identifying an optical disk to be recorded and reproduced at a time and a mark for identifying the front and back of these optical disks are provided, so that these optical disks and their insertion states are identified, and various optical disks are set in a mode suitable for the optical disks and the insertion states. This has the effect that recording and reproduction can be performed.

When a two-layer type optical intensity modulation type magneto-optical recording medium is used, a single initialization magnet for supporting a unidirectional initial magnetizing magnetic field is provided on both front and rear surfaces, and the polarity of a recording signal is changed. Are set to reverse polarities on the front and back, and with a simple configuration, there is an effect that two-layer magneto-optical modulation recording for simultaneous recording on the front and back can be easily realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical disk device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a recording groove format of an optical disc recording medium used in one embodiment of the present invention.

FIG. 3 is a perspective view of a general cartridge.

FIG. 4 is a diagram showing a rotation direction of a motor for driving an optical disk in one embodiment of the present invention.

FIG. 5 is an explanatory diagram of an embodiment in which the present invention is applied to a magneto-optical disk drive of a two-layer film light intensity modulation system.

FIG. 6 is an explanatory view of a conventional two-layer film light intensity modulation type magneto-optical disk device.

[Explanation of symbols]

 Reference Signs List 1 optical disk device 2 upper (front) optical head 3 lower (back) optical head 4 optical disk 5 cartridge 6 cartridge identification sensor 7 cartridge loading mechanism 8 control circuit 9 spindle motor (optical disk drive motor) 10 head loading mechanism 11 (of head) Base 12 Format (recording groove) 13 Light spot (recording start position) 14 Disk rotation direction 15 Cartridge identification hole 16 B-side auxiliary layer 17 A-side auxiliary layer 18 B-side recording layer 19 A-side recording layer 20 Initializing magnet 21 Initial magnetization Direction 22 Auxiliary layer magnetization direction 23 A-side recording magnet 24 A-side recording magnet magnetization direction 25 B-side recording magnet 26 B-side recording magnet magnetization direction

────────────────────────────────────────────────── (5) Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G11B 19/12 501 G11B 19/12 501M (56) References JP-A-59-94242 (JP, A) JP-A-3-150736 (JP, A) JP-A-2-33751 (JP, A) JP-A-2-156452 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 19/02 501 G11B 11 / 105 G11B 19/12 501

Claims (2)

(57) [Claims] 1. A signal is simultaneously recorded on both front and rear recording surfaces by using a two-layer type optical intensity modulation type magneto-optical disk recording medium having recording surfaces of recording track formats in opposite directions on both sides.
An optical disc device for reproduction , wherein the two-layer magneto-optical disc recording medium is formed from an auxiliary layer uniformly magnetized initially and a recording layer on which information is recorded, and one of the front and back of the recording medium At least a first recording magnet that applies a bias magnetic field to the recording layer in a direction opposite to the initial magnetization direction. The other side of the front and back of the recording medium has a first recording magnet opposite to the initial magnetization direction. At least a second recording magnet for applying a bias magnetic field to the recording layer in a direction, and a single initialization magnet for simultaneously applying a unidirectional initial magnetization magnetic field to each of the auxiliary layers on the front and back of the recording medium, Light, wherein the direction of the initial magnetization in the auxiliary layer and the polarity due to the bias magnetic field in the recording layer are set to be opposite to each other on the front and back recording surfaces as viewed from each surface. Disk device. 2. An auxiliary layer which is uniformly magnetized and a recording of information.
The recording layer is formed from the recording layer to be recorded, and has a recording surface of a recording track format in the opposite direction on the front and back , and the direction of the initial magnetization and the polarity due to the bias magnetic field in the recording layer are viewed from each surface on the front and back recording surfaces. An optical disc device for recording and reproducing signals using a first magneto-optical disc recording medium of a two-layer type light intensity modulation method in which the directions are reversed.
Therefore, instead of the first magneto-optical disk recording medium, a uniform
From the auxiliary layer that is initially magnetized and the recording layer on which information is recorded
A second magneto-optical disk recording medium of a two-layer type light intensity modulation system formed and having a recording surface on one side of the disk , or a recording surface of a recording track format in the same direction on both sides, and the direction of the initial magnetization and A third magneto-optical disk recording medium of a two-layer type light intensity modulation system in which the polarity of the recording layer due to the bias magnetic field is the same in the front and back recording surfaces when viewed from each surface, The first, second, and third magneto-optical disk recording medium may be any one of the first, second, and third magneto-optical disks.
A medium identification mark for identifying whether the medium is a recording medium is provided, and a front / back identification mark for identifying the front / back is provided for each of the first, second and third magneto-optical discs.
When using a recording medium, the medium identification mark and the front and back
By detecting the identification mark, the recording track flag is detected.
The direction of the format and the polarity of the bias magnetic field, and
Drive the disc according to the insertion state of the magneto-optical disc.
Magneto-optical disk recording medium using moving part and recording / reproducing part
An optical disk device characterized in that switching is performed so as to conform to the requirements.