JP3050252B2 - Magneto-optical disk and magneto-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 a magneto-optical disk and a magneto-optical disk drive.

[0002] Magneto-optical disks are expected to be used for recording image information in the future. For this purpose, it is necessary to further increase the recording capacity.

In general, a magneto-optical disk 1 is constructed as shown in FIG.
0. Reference numeral 2 denotes a data recording area in which data is recorded, and a plurality of data recording areas are formed in the circumferential direction, and information signals are recorded therein as changes in the perpendicular magnetization direction. Reference numeral 3 denotes an SM (sector mark) / ID (address) recording area, which is formed at a position preceding each data recording area 2 and in which SM and ID are recorded.

[0004]

2. Description of the Related Art When a part of a conventional magneto-optical disk 1A is enlarged, as shown in FIGS. 11 and 12, a land 11 between adjacent guide grooves 10 constitutes a track 12, and a guide groove 10 is formed. Is a structure that does not constitute a track.

The distance a between adjacent guide grooves 10 is 1.6 μm.
The width b of the guide groove 10 is about 0.6 μm, and the depth c of the guide groove 10 is about 60 nm.

Reference numeral 13 denotes a data recording area in which data is recorded as a change in the perpendicular magnetization direction (hereinafter referred to as magneto-optical recording).

Reference numeral 14 denotes an SM / ID recording area. At the head of this area 14, SM is recorded as a pit row 15, and subsequently, ID is also recorded as a pit row 16 (hereinafter referred to as pit row recording).

[0008] The SM pit row 15 informs that there is an ID behind the SM pit row 15 and has the same pattern for all tracks.

Therefore, for SM, crosstalk is not a problem.

The ID pit row 16 represents the number of a track, and the pattern differs for each track.

[0011] Therefore, for ID, crosstalk becomes a problem, and it is necessary to suppress this. This is the premise of the present invention.

FIG. 13 shows a magneto-optical disk drive 20 for the magneto-optical disk 1A.

Reference numeral 21 denotes an optical head, which is a semiconductor laser 2
The laser beam emitted from the laser beam 2 passes through the collimator lens 23 and the beam splitter 24 and is condensed as a spot 26 on the disk 1A by the objective lens 25, reflected and returned there, branched by the beam splitter 24, and λ
The beam splitter is split into two light beams by a polarizing beam splitter 28 through a half plate 27, one of which is condensed on a photodetector 30 through a lens 29, and the other is condensed on a split photodetector 32 through a lens 31. The difference between the output of the photodetector 30 and the output of the split photodetector 32 is obtained by the differential amplifier 33, and the information recorded as the change in the perpendicular magnetization direction is reproduced using the change in the rotation of the polarization plane. Signal (hereinafter referred to as magneto-optical signal)
Is output. The amplifier 34 calculates the sum of the output of the photodetector 30 and the output of the divided photodetector 32, and reproduces a signal recorded as a pit string by using a change in reflectance (SM / ID; (Referred to as a reflectance signal).

Further, the divided photodetector 3 is provided by a differential amplifier 36 constituting a tracking servo circuit 35.
The difference between the outputs from the two light receiving units is obtained, and a tracking control signal is obtained. The tracking control signal is applied to the tracking actuator 37 to control the tracking.

Here, in the above-mentioned disk 1A, the land 11 forms a track, and the relationship between the tracking error signal and the output level of the tracking control signal is represented by the line rising to the right as shown by the line I in FIG. Become.

The line 40 from which the magneto-optical signal is output is connected to a demodulator 41.

The line 42 from which the reflectance signal is output is S
It is connected to the M detector 43 and the ID detector 44.

Here, the spot 26 in FIG.
The operation for relatively scanning the ID recording area 14 and subsequently the data recording area 13 will be described.

First, a reflectance signal is output to a line 42, and an SM detector 43 detects SM. Then, the ID detector 44 is activated by the output from the SM detector 43, and the ID detector 44 detects the ID.

When the ID detector 44 detects the ID, the demodulator 41 is activated by the output of the ID detector 44, and the magneto-optical signal output following the reflectance signal is demodulated and recorded in the data recording area 13. The previous data is reproduced.

The output of the ID detector 44 is
It is also supplied to a controller 45 that controls the whole.

[0022]

The above-mentioned magneto-optical disk 1A has a problem that the recording capacity is not sufficient because only the lands 11 between the guide grooves are used as tracks.

In order to increase the recording capacity, see, for example,
It is conceivable to apply the concept shown in US Pat. No. 18832 to a magneto-optical disk and to use a guide groove in addition to a land as a track.

FIG. 15 shows a main part of the magneto-optical disk 1B based on the above concept.

The land 52 forms the track T, and the guide groove 53 also forms the track T.

Reference numeral 54 denotes a data recording area.

Reference numeral 55 denotes an ID recording area.
Each time, an ID pit row 56 is formed.

The number of tracks of the magneto-optical disk 1B is twice that of the magneto-optical disk 1A shown in FIG.
Data recording capacity doubles.

In the data recording area 13, since data is magneto-optically recorded, crosstalk, which is leakage from a track adjacent to a track to be reproduced, is -3.
2 dB, no problem.

The present inventor has confirmed that the error starts to increase when the crosstalk becomes about -24 dB as a result of the experiment.

With respect to the ID recording area 56, when a desired track T is reproduced, the crosstalk which is the amount of a signal reproduced from the adjacent track T is -1.
It was as large as 3dB.

For this reason, there is a problem that the ID of the desired track cannot be read correctly and an error occurs in reproduction.

It should be noted that the ID is recorded as a pit string when the stamper is used to mold the substrate of the magneto-optical disk.
It is to build.

It is an object of the present invention to provide a magneto-optical disk capable of suppressing crosstalk of a reproduction ID by forming an ID recording area on adjacent tracks by recording a pit string on one side and magneto-optically recording on the other. And

[0035]

According to the first aspect of the present invention, the land between the adjacent guide grooves forms one track, and the guide groove itself forms another track, and data is perpendicular to the data recording area. A magneto-optical disk recorded as a change in magnetization direction, wherein an address is recorded as a change in the perpendicular magnetization direction for the one track, and an address recording area in which the address is recorded as a pit string for the another track. It has a configuration to have.

According to a second aspect of the present invention, the land between the adjacent guide grooves constitutes one track, and the guide groove itself constitutes another track, and data is recorded in the data recording area as a change in the perpendicular magnetization direction. A magneto-optical disc having an address recording area in which the address of one track is recorded as a pit string and the address of another track is recorded as a change in the perpendicular magnetization direction. is there.

According to a third aspect of the present invention, there is provided a magneto-optical disk drive for reproducing the magneto-optical disk according to the first or second aspect, wherein a portion in which a signal is recorded as a change in the perpendicular magnetization direction is relatively scanned and polarized. The data and address are reproduced by using the change in the rotation of the surface, and the reproduced data and address are output as a first reproduced signal. The portion where the signal is recorded as a pit row is relatively scanned to use the change in the reflectance. An optical head that reproduces the address and outputs the second reproduced signal as a second reproduced signal, and selectively supplies the address reproduced signal and the second reproduced signal of the first reproduced signal to the address detector. And means for performing the operation.

[0038]

According to the first and second aspects of the present invention, the address recording area functions to sufficiently suppress crosstalk from the address of another track when reproducing the address of one track, and to change the address of another track. It works so that crosstalk from the address of one track at the time of reproduction is sufficiently suppressed.

The control means of the present invention operates so that the address is normally reproduced.

[0040]

【Example】

FIG. 1 shows a main part of a magneto-optical disk 60 according to a first embodiment of the present invention.

61 is a guide groove, 62 is an adjacent guide groove 61
It is a land between. The width e of the guide groove 61 is 1 μm, and the interval f between the adjacent guide grooves 61 is 2 μm.

The land 62 constitutes the track T ₁ , and the guide groove 61 constitutes the track T ₂ .

Reference numeral 63 denotes a data recording area, 64 denotes an SM recording area, and 65 denotes an ID recording area.

A magnetic film (not shown) for magnetizing in the vertical direction is formed on the entire surface of the magneto-optical disk 60.

[0045] With regard to SM recording area 64, for the track T _2, SM is are pit string recording. 66
Is an SM recorded in a pit string.

On the track T ₁ , SM is magneto-optically recorded. 67 is a magneto-optically recorded SM. Arrow 68 indicates the direction of perpendicular magnetization.

[0047] With regard to ID recording area 65, for the track T _2, ID is are pit string recording. 70
Is an ID recorded in a pit string.

[0048] As for the track T _1, ID is a magneto-optical recording. An ID 71 is magneto-optically recorded.

FIG. 8 shows a recording mode of the magneto-optical disk 60.

In the data recording area 63, data is magneto-optically recorded for each of the tracks T ₁ and T ₂ .

The magneto-optical disk 60 having the above configuration is manufactured through the steps shown in FIG.

First, a substrate forming step 75 is performed.

Here, injection molding is performed in a mold into which a stamper is incorporated to form a substrate having guide grooves and pit rows.

Next, a magnetic film forming step 76 is performed to form a perpendicular magnetic film on the entire surface of the substrate.

Next, an SM / ID recording step 77 is performed.

[0056] Here, subjected to a recording apparatus to a disk which is the above semi-finished products, based on the pit row that has already been recorded, SM and the magneto-optical recording in the SM recording area 64 of the track T _1, followed by ID recorded The ID is magneto-optically recorded in the area 65.

Thus, the magneto-optical disk 60 is completed.

Next, a magneto-optical disk drive 80 for reproducing the magneto-optical disk 60 will be described with reference to FIG.

In FIG. 3, portions corresponding to the components shown in FIG. 12 are denoted by the same reference numerals.

The device 80 has a configuration in which three switches 81, 82 and 83 are added to the device 20 of FIG. Switches 81, 82, and 83 are controlled by controller 45A.

[0061] Switch 81 is is provided with an input stage of the SM detector 43, a contact piece is connected to contact 81 _-1 is input reflectance signal, switching switched magneto-optical signal to a contact 81 _-2 side Input.

[0062] Switch 82 is provided with an input stage of the ID detector 44, the contact piece is connected to contact 82 _-1 is input reflectance signal, when connected to the contacts 82 _-2 magneto-optical signal Input.

The switch 83 is provided at the input stage of the tracking servo circuit 35 and reverses the characteristics of the servo circuit 35.

This is because the relationship between the tracking error when the spot scans the track T _{1 of the} land 62 and the output from the divided photodetector 32 and the tracking when the spot scans the track T ₂ of the guide groove 61. This is because the relationship between the error and the output from the divided photo detector 32 is opposite to each other.

Next, reproduction of the magneto-optical disk 60 will be described.

The track T _{1 having the} spot of the land 62
The switch 81 is connected to the contacts 81 _-2 , the switch 82 is connected to the contacts 82 _-2 , and the switch 83 is connected to the contacts _83-1 and 83 _-2 according to the control signal from the controller 45A.

When the spot 26 scans the SM recording area 64, a magneto-optical signal reproduced from the magneto-optical recording SM 67 is input to the SM detector 43 via the switch 81,
Is detected. Pit row recording S adjacent tracks T ₂
The contents of the M66 magneto-optical recording of the tracks T ₁ SM6
Since the content is the same as that of No. 7, the crosstalk is not a problem.

When the SM is detected, the ID detector 44 is activated.

Subsequently, the spot 26 is placed in the ID recording area 65.
Is scanned, a magneto-optical signal obtained by reproducing the magneto-optical recording ID 71 is input to the ID detector 44 via the switch 82, and the ID is detected.

Here, the adjacent track T ₂
The crosstalk leaked from the pit string recording ID 70 will be described.

As a result of the measurement, the crosstalk value was −33.
dB (FIG. 9).

This crosstalk value is the allowable value of −24 dB.
And therefore no error occurs, the magneto-optical recording I
D71 is correctly detected.

[0073] Then, the spot 26 scans the data area 63, signals obtained by reproducing the data that has been magneto-optical recording in the track T ₁ of the land 62 is demodulated by the demodulator 41, the data is output.

[0074] crosstalk value also is a signal amount of read data that is the magneto-optical recording in the track T ₂ adjacent this time is as small as -34 dB (Fig. 9), there is no problem.

The tracking control is normally performed based on the line I in FIG.

The spot is the track T _{2 of the} guide groove 61
When scanning a by the control signal from the controller 45A, switch 81 contacts 81 _-1, the switch 82 contacts 82 _-1, the switch 83 is connected to the contact 83 _-3, 83 _-4 side.

When the spot 26 scans the SM recording area 64, a reflectance signal obtained by reproducing the pit string recording SM 66 is input to the SM detector 43 via the switch 81,
M is detected. At this time, the crosstalk from the magneto-optical recording SM tracks T ₁ adjacent in the same manner as described above is not a problem.

When the SM is detected, the ID detector 44 is activated.

Subsequently, the spot 26 is placed in the ID recording area 65.
Is scanned, a reflectance signal obtained by reproducing the pit string recording ID 70 is input to the ID detector 44 via the switch 82, and the ID is detected.

At this time, the adjacent track T ₁
The crosstalk leaked from the magneto-optical recording ID 71 will be described.

As a result of the measurement, the crosstalk value was −40.
dB (FIG. 9).

This crosstalk value is the allowable value of -24 dB.
Therefore, no error occurs, and the pit string record ID 70 is correctly detected.

[0083] Then, the spot 26 scans the data area 63, signals obtained by reproducing the data that has been magneto-optical recording in the track T ₂ of the guide groove 61 is demodulated by the demodulator 41, the data is output.

At this time, the crosstalk value from the adjacent track T ₁ is as small as −34 dB (FIG. 9), and there is no problem.

In the case of the guide groove 61, the land 62
In this case, the relationship between the direction of the spot shift and the output of the photodetector 32 is reversed.
Are connected as described above, the tracking control is normally performed based on the line I in FIG.

[Embodiment 2] Next, a magneto-optical disk 60A according to a second embodiment of the present invention will be described with reference to FIG.

The magneto-optical disk 60A has a configuration in which the pit row record SM66 and the pit row record ID 70 in FIG.

In FIG. 4, the configuration is the same as that shown in FIG. 1 except for the pit row record SM 66A and the pit row record ID 70A.

The structure of the magneto-optical disk 60A is shown in FIG.
Are shown together.

FIG. 9 shows the crosstalk value of the magneto-optical disk 60A.

[0091] With regard ID recording area 65, the crosstalk value from pit row recording ID70 of the track T ₂ are a -29 dB, the crosstalk value from the magneto-optical recording ID71 of tracks T ₁ was -41 dB.

The crosstalk value in the data recording area 63 was -32 dB.

[Embodiment 3] Next, a magneto-optical disk 90 according to a third embodiment of the present invention will be described with reference to FIG.

The guide groove 91 extends from the data recording area 63 to the SM recording area 64 and the ID recording area 64.

The guide groove 91 forms the track T ₁ and the land 92 forms the track T ₂ .

[0096] As for SM recording area 64 has a pit row recording SM93 to track T _1, having a magneto-optical recording SM94 to track T _2.

[0097] With regard ID recording area 65, as with SM recording area 64 described above, has a pit row recording ID95 in the track T _1, a magneto-optical recording in the track T ₂ ID 96
Having.

The configuration of the magneto-optical disk 90 is also shown in FIG.

FIG. 9 shows the crosstalk value of the magneto-optical disk 90.

[0100] With regard ID recording area 65, the crosstalk value from pit row recording ID96 of tracks T ₁ is -34 dB, the crosstalk value from the magneto-optical recording ID95 of the track T ₂ are was -43 dB.

The crosstalk value in the data recording area 63 was -33 dB.

Embodiment 4 Next, a magneto-optical disk 60B according to a fourth embodiment of the present invention will be described with reference to FIG.

[0103] The optical disk 60B is a SM recording area 64 of the magneto-optical disk 60 in FIG. 1, for the track T _1, is obtained by a structure in which a pit train recording SM66.

The ID recording area 65 is the same as the magneto-optical disk 60 shown in FIG.

The configuration of the magneto-optical disk 60B is shown in FIG.
Are shown together.

In the ID recording area 65, the track T ₂
The crosstalk value from the pit string recording ID 70 is -32
a dB, the crosstalk value from the magneto-optical recording ID71 of tracks T ₁ was -41 dB (see FIG. 9).

Embodiment 5 Next, a magneto-optical disk 90A according to a fifth embodiment of the present invention will be described with reference to FIG.

[0108] The magneto-optical disk 90A is a SM recording area 64 of the magneto-optical disc 90A in FIG. 7, the track T ₂
No pit is recorded, and the pit row record SM93
Is provided.

The ID recording area 65 is the same as in FIG.

The structure of this magneto-optical disk 90A is shown in FIG.
Are shown together.

In the ID recording area 65, the track T ₁
The crosstalk value from the pit row record ID 96 of the − is -34.
a dB, the crosstalk value from the magneto-optical recording ID95 of the track T ₂ are was -42 dB (see FIG. 9).

In the magneto-optical disks 60A, 90, 60B and 90B of the second to fifth embodiments, the ID is normally detected without any error.

[0113]

As described above, according to the first or second aspect of the present invention, an address can be read out normally without error, and the recording capacity can be increased while ensuring stable recording and reproduction. Can be realized.

According to the third aspect of the present invention, it is possible to normally perform data recording and reproduction on a magneto-optical disk with an increased recording capacity.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a magneto-optical disk according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the magneto-optical disk of FIG.

FIG. 3 is a diagram showing an embodiment of a magneto-optical disk device according to the present invention.

FIG. 4 is a diagram showing a main part of a magneto-optical disk according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a main part of a magneto-optical disk according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a main part of a magneto-optical disk according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a main part of a magneto-optical disk according to a fifth embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a magneto-optical disk according to each embodiment of the present invention.

FIG. 9 is a table showing crosstalk when reproducing an ID recording area and a data recording area of a magneto-optical disk according to each embodiment of the present invention.

FIG. 10 is a diagram showing the appearance of a general magneto-optical disk.

FIG. 11 is an enlarged view showing a part of a conventional magneto-optical disk.

FIG. 12 is an enlarged view showing a part of FIG. 11;

FIG. 13 is a diagram showing an example of a conventional magneto-optical disk device.

FIG. 14 is a diagram illustrating a relationship between a tracking error amount and an output level of a tracking control signal.

FIG. 15 is an enlarged view showing a part of the magneto-optical disk devised by the present inventors.

[Explanation of symbols]

 Reference Signs List 21 optical head 35 tracking servo circuit 40 magneto-optical signal output line 42 reflectance signal output line 43 SM detector 44 ID detector 45A controller 60, 60A, 60B, 90 magneto-optical disk 61, 91 guide groove 62, 92 land 63 data Recording area 64 SM recording area 65 ID recording area 66, 93 Pit-row recording SM 67, 94 Magneto-optical recording SM 68 Arrow indicating the direction of perpendicular magnetization 70, 96 Pit-row recording ID 71, 95 Magneto-optical recording ID 75 Substrate forming step 76 Magnetic film forming process 77 SM / ID recording process 80 Magneto-optical disk device 81, 82, 83 Switch

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI G11B 7/004 G11B 7/004 Z 7/007 7/007

Claims (3)

(57) [Claims] A land (6) between adjacent guide grooves (61).
2) constitute _one track (T ₁ ) and the guide groove (6)
1) A magneto-optical disk in which another track (T ₂ ) itself constitutes, and data is recorded in a data recording area (63) as a change in the perpendicular magnetization direction, and the one track (T ₁ ) The address was recorded as a change in the perpendicular magnetization direction (71), and for the other track, the address was recorded as a pit string (7).
0) A magneto-optical disk characterized by having an address recording area (65). 2. A land (9) between adjacent guide grooves (91).
2) constitute _one track (T ₁ ) and the guide groove (9)
1) itself constitutes a different track (T _2), data in the data recording area (63) is a magneto-optical disc which is recorded as a change in the perpendicular magnetization direction, for the one of the tracks (T ₁₎ is The address is recorded as a pit string (96), and for the other track, the address is recorded as a change in the perpendicular magnetization direction (9).
5) A magneto-optical disk having an address recording area (65). 3. A magneto-optical disk apparatus for reproducing a magneto-optical disk according to claim 1, wherein a portion where a signal is recorded as a change in a perpendicular magnetization direction is relatively scanned to change a rotation of a polarization plane. And reproduces the data and address as a first reproduced signal, and relatively scans a portion where the signal is recorded as a pit row to reproduce the address using a change in reflectance. Optical head (2)
1), the address reproduction signal of the first reproduction signal and the second
(45A, 81, 82) for selectively supplying the reproduced signal to the address detector (44).