JPH08273168A - Recording and reproducing method of optical disk - Google Patents

Abstract

PURPOSE: To shorten a time required for seek by tracking either a land or a groove at a first step and the target land or groove at a second step. CONSTITUTION: A magnetooptical recording medium is manufactured by forming a silicon nitride layer 2, a TbFeCo recording layer 3 and the silicon nitride layer 2 in this order on a poly-carbonate substrate 1, 1.2mm in thickness, 90mm in diameter, a 1.6μm in track pitch, 0.8μm in widths between a land 4 and a groove. Seeking operation is dividing into two steps, regardless of the location of a target track in a land 4 or in a groove 5 in a first step, an optical pickup is brought close to the vicinity of the target track while counting a number of guide grooves and seeking operation is performed by changing over a tracking circuit if necessary and tracking on the target track in a second step. Seeking operation is randomly performed 110-4 times on the magnetooptical recording medium by a groove recording method in the sequence shown in the figure and the required seek time is secured in such an extend as same as conventional land recording method and groove recording method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording / reproducing method, and more particularly, it is suitable for an optical disk recording / reproducing method in which information is recorded on both land and groove portions of the optical disk.

[0002]

2. Description of the Related Art An optical disk capable of storing information at high density is expected to expand its market as a large capacity external memory. For example, in the size of 3.5 inches in diameter, the read-only ROM type and the magneto-optical type and the partial ROM type in which the magneto-optical and ROM are mixed are standardized by the ISO standard, and it has already become a large market size. There is. In addition, CD-ROMs and MDs (minidiscs) are rapidly becoming popular.

Recording and reproduction are performed on these optical disks by narrowing a laser beam by an optical pickup and irradiating the recording film of the optical disk as a light spot having a small diameter. The recorded portion is called a mark, and the area where the marks are continuously arranged is called a track. In order to achieve high recording density, it is necessary to arrange the tracks in an orderly manner, and therefore it is necessary to guide the beam along the tracks so that the light spot does not enter the adjacent tracks. That is, a guide for tracking is required. This guide is generally in the form of a concave or convex groove,
The disk is formed in a spiral shape from the inner circumference to the outer circumference. This groove is called a guide groove.

The guide groove will be described in more detail. According to the definition of ISO standard, the concave portion when viewed from the optical pickup, that is, the far portion is called a land, and the convex portion when viewed from the pickup, that is, the near portion. The part is called a groove. It has traditionally been common to record information on either lands or grooves. Recording on a land is called a land recording / reproducing method, and recording on a groove is called a groove recording method. A route for recording information is called a track. The distance from the center of a track to the center of the adjacent track is called the track pitch.

The guide groove is generally formed on the master by exposing it with a laser beam when manufacturing the master of the optical disk. A tracking guide is formed on the substrate by using a mold called a stamper to which the pattern of this master is transferred and replicating by plastic injection molding or casting of an ultraviolet curable resin. When recording or reproducing, when the target track is specified, the number of guide grooves between the target position and the current position of the optical pickup is recognized, and then the optical pickup is moved toward the track of the target number. While counting the number of, move it to its vicinity. Then, one track is tracked and the track number is read. If the number is not the target track number, the track is moved to the target track number and the target track is tracked. This operation is called seek.

Further increasing the recording density will further increase the advantages of the optical recording medium. However, if the track pitch is unnecessarily narrowed to increase the recording density, signal crosstalk, which is a phenomenon that information from adjacent tracks leaks in, becomes large, and the probability of information reproduction error increases. Therefore, land / groove recording has been proposed as a technique that has received attention. This is an attempt to double the capacity by recording on both of the land and the groove, which was generally recorded on either of them. In this technique, when the groove depth is appropriately selected, the signal crosstalk between the adjacent land portion and groove portion can be suppressed to a very small level, so that highly reliable high-density recording with few reproduction errors becomes possible.

[0007]

In the land / groove recording / reproducing system, the track being tracked may be either a land or a groove, and the target track to be recorded or reproduced next may be either the land or the groove. There is a possibility. However, the land tracking and the groove tracking have different circuit configurations. Therefore, in the land / groove recording / reproducing system, first, it is determined whether the target track is a land or a groove, and the tracking circuit configuration is switched according to it, and then the seek is performed.

Therefore, there is a problem that the time required to complete the seek for the target track becomes longer than that in the land recording method or the groove recording method. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a recording and reproducing method in which the seek time is short even in the land / groove recording method.

[0009]

The present inventor divides the seek operation into two steps. In the first step, regardless of whether the target track is a land or a groove,
While counting the number of guide grooves, the optical pickup is brought close to the target track, and in the second step, the seek operation is performed by switching the tracking circuit and tracking to the target track as needed, so that the seek time is short, Further, they have found that the cost is low and have completed the present invention.

Therefore, the present invention firstly provides a method for seeking an optical pickup for recording on an optical disk which has a spiral or concentric tracking guide groove and which is recordable and reproducible. In one step, tracking is performed on either the land or groove, and in the second step, a tracking method is performed on the target land or groove. In a method of seeking an optical pickup for reproduction on an optical disk that has concentric tracking guide grooves and is capable of recording and reproduction, in the first step, tracking is performed on either a land portion or a groove portion. In the second step, track the target land or groove. A method for reproducing an optical disk, "characterized by Ukoto.

[0011]

In the conventional method, since it is determined whether the target track is a land or a groove, switching is made to the tracking circuit configuration according to the determination, and seek is performed, it takes time to determine and switch the circuit. On the other hand, according to the research by the present inventor, since the above-described operation is not performed in the present invention, the seek time can be shortened and the cost can be suppressed low.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

[0013]

[Example] Thickness 1.2 mm, diameter 90 mm, track pitch 1.6
A magneto-optical recording medium shown in FIG. 2 was manufactured by forming a silicon nitride layer, a TbFeCo recording layer and a silicon nitride layer in this order on a polycarbonate substrate having a land width of 0.8 μm and a land and groove width of 0.8 μm. Next, 1 × 10 ⁻⁴ was applied to the above magneto-optical recording medium by the land / groove recording method in the sequence shown in FIG.
The seek was performed randomly at random, and the average seek time required (average seek time) was measured. As a result, the average seek time was 32 msec, and the seek time comparable to that of the conventional land recording method and groove recording method could be secured.

[0014]

Comparative Example The same recording was performed on the same magneto-optical recording medium by the land / groove recording method by the sequence of the conventional method shown in FIG. 3, and the same measurement was performed. As a result, the average seek time was 52 msec, which was 60% or more as compared with the example.

[0015]

As described above, according to the present invention, it is possible to provide a recording and reproducing method in which the seek time is short even in the land / groove recording method.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating an operation sequence of a seek operation according to the present invention.

FIG. 2 is a conceptual diagram showing a vertical cross section of a magneto-optical recording medium used in the present invention.

FIG. 3 is a conceptual diagram illustrating an operation sequence of a seek operation according to a conventional method.

[Explanation of symbols]

 1 ... Substrate 2 ... Silicon Nitride Layer 3 ... TbFeCo Recording Layer 4 ... Land 5 ... Groove

Claims (2)

[Claims] 1. A method of seeking an optical pickup for recording on an optical disk which has a spiral or concentric tracking guide groove and is capable of recording and reproduction, wherein a land or a groove is formed in the first step. The optical disk recording method is characterized in that either one of the two is tracked, and in the second step, the target land or groove is tracked. 2. A method of seeking an optical pickup for reproduction on an optical disk capable of recording and reproducing, which has a spiral or concentric tracking guide groove, in the first step, a land portion or A method of reproducing an optical disk, wherein tracking is performed on either one of the groove portions and, in the second step, tracking is performed on a target land or groove.