JPH02203447A - Magneto-optical disk - Google Patents

Abstract

PURPOSE:To shorten the access time by providing pilot land parts previously formed with the one-round component of the land parts corresponding to tracks to the depth different from the depth of preformats or the bit length different therefrom in the positions every predetermined number of unit tracks. CONSTITUTION:The track error signals (TES) obtd., when an optical head applied with focusing servo is accessed in the direction perpendicular to pregrooves 6, are varied in amplitude by the pilot land parts 9 provided at every predetermined number of unit tracks (for example, 1,000 tracks). Jumping at a high speed at every 1,000 tracks is enabled merely by applying a slice level to such TES of the different amplitudes and counting the same. The jumping is switched to an ordinary counting method at the point of the time when the number of the tracks up to the target tracks attains <1,000 tracks. The count number of the pregrooves 6 is decreased in this way and the access time is shortened.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a magneto-optical disk used in a magneto-optical disk device for recording information, and provides a magneto-optical disk that can reduce access time by reducing the number of pregroove counts. In a magneto-optical disk, the land portions and pregrooves for recording information are alternately provided on tracks of a substrate, and preformats for addresses are formed at predetermined intervals on the land portions. , a pilot land portion is provided at a position for each predetermined number of unit tracks, and a pilot land portion is formed with a depth different from that of the preformat or a bit length different from that of the preformat for one circumference of the land portion corresponding to the track, and the optical head Configure for high-speed access when accessing the disk.

[Industrial application field]

The present invention relates to a magneto-optical disk used in a magneto-optical disk device for recording information.

Magneto-optical recording and reproducing devices are a field in which the market is rapidly expanding from recording and reproducing image information to devices that can record computer codes due to their features such as mass storage, non-contact recording, and removable media. It is.

[Conventional technology]

Fig. 3 is a diagram showing the structure of a conventional magneto-optical disk, in which Fig. 3(a) is a partially cutaway perspective view of the magneto-optical disk; An enlarged sectional view of part A is shown.In both figures, reference numeral 1 denotes a magneto-optical disk, which is composed of the following parts (2 to 8).

2 is a transparent substrate formed into a disc shape from a member such as glass or plastic; 3 is a protective film; 4 is a recording layer; and 5 is a protective film. Further, a guide groove (pregroove) 6 for track servo is spirally carved in the substrate 2 from the center toward the outside. Reference numeral 7 denotes a land portion for recording information, and the land portion 7 is provided with preformats 8 provided in advance at predetermined intervals, and data is recorded between the preformats 80.

For example, in the case of a magneto-optical disk having a diameter of 30 cm, the number of the 60 pregrooves is approximately 54,000 at a pitch of 1.6 μm. When the optical head (not shown) accesses the magneto-optical disk from the current track to the target track, an electrical signal is generated by photoelectrically converting the change in the amount of light due to the pregroove 6 traversed by the known bush pull method, that is, the track Error signal (Tr
Track (group; groove) to jump from ack Error Signal H (hereinafter abbreviated as TBS)
It is configured to find the target track while counting the number.

FIG. 4 is a diagram showing a TES using a conventional magneto-optical disk. In this waveform diagram, the horizontal axis represents the position (travel distance) of the optical head, and the vertical axis represents the amplitude (voltage). Pregroove 6
The signal waveform corresponding to the pregroove, which is detected by crossing the
can be known.

[Problem to be solved by the invention]

In the above-mentioned conventional magneto-optical disk 1, when the optical head attempts to access a track on the magneto-optical disk as described above, it is necessary to count all the pregrooves to jump, and this counting operation requires an access time. There was a problem that it took a lot of time.

The present invention has been made in view of the above-mentioned conventional problems.
An object of the present invention is to provide a magneto-optical disk capable of shortening access time by reducing the number of pregroove counts.

[Means to solve the problem]

FIG. 1 is a diagram showing the configuration of the present invention. A magneto-optical disk 1 comprising alternately land portions 7 and pregrooves 6 for recording information on tracks of a substrate 2, and address preformats 8 formed at predetermined intervals on the land portions 7. A pilot land portion 9 is provided at a position for each predetermined number of unit tracks, and a pilot land portion 9 is formed by forming one circumference of the land portion 7 corresponding to the track with a depth different from that of the preformat 8 or a bit length different from that of the preformat 8. When accessing the magneto-optical disk 1, the configuration is such that high-speed access is possible.

[For production]

The TBS obtained when the optical head to which the focus servo is applied accesses the pregroove 6 in the perpendicular direction has a different amplitude depending on the pilot land portion 9 provided for each predetermined number of unit tracks (for example, 10001-rack). TBS is obtained.

By simply multiplying and counting these TESs with different amplitudes by the slice level as shown in Figure 2, it became possible to jump every 1000 tracks at high speed, and the number of tracks to reach the target track was less than 1000 ranks. By switching to the conventional counting method at this point,
It is possible to reduce the number of pregroove counts and shorten the access time.

〔Example〕

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

In order to make the explanation of the configuration and operation easier to understand, the same parts are given the same reference numerals throughout the series, and repeated explanation thereof will be omitted.

FIG. 1 is a diagram showing the structure of the magneto-optical disk of the present invention, in which FIG. 1(a) is a partially cutaway perspective view of the magneto-optical disk, and FIG. 1(b) is a diagram showing the structure of the magneto-optical disk of the present invention. An enlarged sectional view of part B is shown. In both figures, reference numeral 9 denotes a pilot land portion, and the depth Hb of its recording bits with respect to the recording layer 4 is different from the depth Ila of the recording bits of the preformat 8 provided in advance with respect to the recording layer 4. ′γ is formed.

Further, the bit length may be formed to be longer than the preformat 8.

FIG. 2 is a diagram showing the principle of the present invention, and shows the waveform of TBS obtained from the magneto-optical disk of the present invention. Here, 1 and a indicate the number of tracks between adjacent pilot land parts, and this LaO value is the predetermined unit track number (
For example, set to 1ooot-rank). That is, 1
One round of the land portion 7 for every 000 tracks is formed as a pilot land. It can be seen that the amplitudes of T E and S obtained by accessing the optical head perpendicularly to the tracks of the magneto-optical disk 1 formed in this way are reduced in amplitude corresponding to the pilot land portion 9.

It should be noted that there is a concern that the amplitude will decrease when the preformat 8 is crossed to the optical path, but compared to the case when the virion strand section 9 is crossed, the amplitude is much smaller and can be distinguished.

Therefore, by setting the amplitude corresponding to the pilot land portion 9 as P, providing slice levels Va and νh, and detecting the amplitude P that satisfies νa<P<Vb using a comparator (not shown), it is possible to 1 - A signal can be obtained.

That is, the target track position is approached while counting in 10001-rank units, and when the number of tracks to the target track becomes less than 1000 ranks, the count is completed in the cylinder by switching to the conventional counting method. High-speed access is possible.

Note that it is preferable that the pilot land portion 9 be formed at the same time as the preformat 8 is formed.

In FIG. 1, 1 is a magneto-optical disk, 2 is a substrate, 6 is a pregroove, 7 is a land portion, 8 is a brief mat, and 9 is a pilot land portion.

[Effects of the Invention] As is clear from the explanation below-1-, according to the present invention, by setting a predetermined land portion as a pilot land portion, track counting can be omitted, and compared to the conventional method, the track count can be omitted. This has the effect of enabling high-speed access.

[Brief explanation of the drawing]

Fig. 1 shows the configuration of the present invention, Fig. 2 shows the principle of the invention, Fig. 3 shows the structure of a conventional magneto-optical disk, and Fig. 4 shows a TBS using a conventional magneto-optical disk. It is a diagram. 1 Hoshiya appetizer 77 B +Ql -fPφ~town [77 f1 summon 1ri tb) (al figure cq BllPm) <#itt (
! 1 Introduction The depths of the invention 1 Kei 2 Ending 1st figure (Ql -fP- New to the group (Figure tb> Tree 10 Fig. 3Principle to invention

Claims (1)

[Claims] Land portions (7) and pregrooves (6) for recording information are provided alternately on the tracks of the substrate (2), and addresses are provided on the land portions (7) at predetermined intervals. In a magneto-optical disk (1) on which a preformat (8) is formed, one round of the land portion (7) corresponding to a predetermined unit number of tracks is formed on the preformat (8). ) is provided with a pilot land portion (9) formed with a different depth or a different bit length, and is configured to enable high-speed access when an optical head accesses the magneto-optical disk (1). magneto-optical disk.