JPH07110944A - Optical disc - Google Patents

Abstract

PURPOSE:To prevent crosstalk by alternately arranging a groove and a land, providing a header region of the predetermined format for identifying region at the leading area of the user data region of the predetermined length and also arranging header regions on the grooves and lands with a certain deviation in the circumferencial direction of a disc. CONSTITUTION:A land L is formed as a projected region between grooves G and these land and groove are almost equal in size in the radial direction. A land header region HL and a groove header region HG are respectively formed of three regions. Therefore, data may be obtained by tracking the land L. If a laser beam reaches the neighboring groove H under the condition that data are reproduced from the region HL, the laser beam does not detect the region HG. Therefore, data in a proper header region can be obtained when tracking is performed respectively to the land L and groove G. As a result, data can be reproduced adequately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a structure in which grooves and lands are alternately arranged, and in the user data area in which user data of a predetermined data length can be recorded, each user data area is identified at the beginning. And an optical disc in which a header area of a predetermined data format is arranged.

[0002]

2. Description of the Related Art In recent years, optical disk recording apparatuses have tended to have a large data recording capacity. As a method for increasing the capacity, a laser diode used as a light source has a shorter wavelength, a mark edge detection method is applied as a demodulation method during data reproduction, and a track pitch is reduced.

On the other hand, since the phase change type optical disk has a smaller thermal conductivity than the magneto-optical disk, it is possible to form smaller pits (recording marks), and as a result, in principle, data is reproduced from an adjacent recording track when reproducing data. The influence of the crosstalk component can be reduced.

By utilizing such characteristics, as shown in FIG. 5, the groove (guide groove) G used for guiding the laser beam is used as a data recording track together with the land L, thereby increasing the data recording capacity. A recording method that can double the number has also been proposed.

However, when both the land L and the groove G are used as recording tracks in this way,
The following inconveniences occur.

That is, the recording track is divided into sectors having a predetermined data length, and a header area for displaying the sector address of each sector is formed at the head of the user data area of this sector. There is.

The data of the header area is formed by embossing (concavo-convex processing) at the stage of manufacturing the recording medium so that the content is not changed by the optical pickup device. Therefore, in the land L, the header area is formed as a pre-pit, and in the groove G, the header area is formed as a pre-groove including the presence or absence of a groove groove.

On the other hand, when the land L is being tracked, the laser beam reaches the adjacent groove G as well, so that the reflected light component from the pre-groove formed as the header region in the groove G enters the optical system. Returning, as a result, the influence of crosstalk during reproduction of the header area becomes large.

As a method of removing the influence of such crosstalk, for example, as shown in FIG. 5, three laser beams LB1, LB2, and LB3 are used, and data of three adjacent recording tracks are recorded. There is a so-called three-beam method of reproducing and correcting the reproduction signal from the target recording track TT by using the reproduction signals from two adjacent recording tracks TR1 and TR2 other than the target recording track TT (“double track density method”). NEC Iwanaga; Optical Da
(See "Ta Stage '90 Lecture Collection").

[0010]

[Problems to be Solved by the Invention] However, this 3
In order to realize the beam method, a special optical pickup device equipped with a three-beam optical system is required, and the circuit configuration for signal correction becomes complicated, so that the device cost becomes very high. Cause

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical disk capable of suppressing the influence of crosstalk during data reproduction of the header area without using the 3-beam method. I am trying.

[0012]

According to the present invention, grooves and lands are alternately arranged, and user data areas in which user data of a predetermined data length can be recorded are identified at the beginning of each user data area. In the optical disc in which a header area of a predetermined data format for arranging is arranged, the groove and the land are respectively used as data recording areas, and the header area formed in the groove and the header area formed in the land are recorded in the disc. It is arranged such that the arrangement position in the circumferential direction is shifted.

Further, in the user data area in which grooves and lands are alternately arranged and user data of a predetermined data length can be recorded, a header of a predetermined data format for identifying each user data area is provided at the head of the user data area. In the optical disc in which the areas are arranged, the groove and the land are used as data recording areas, respectively, and a common header area composed of common data among the data in the header area is formed in the groove and is included in the data in the header area. The disk circumferential position where the data of the non-common header area consisting of non-common data is arranged in the groove is different from the disk circumferential position where the data of the non-common header area is arranged in the land. It is a thing.

Further, in the user data area in which grooves and lands are alternately arranged and user data of a predetermined data length can be recorded, a header of a predetermined data format for identifying each user data area is provided at the beginning of the user data area. In the optical disc in which the areas are arranged, the groove and the land are used as data recording areas, respectively, and the common header area formed by the common data of the data of the header area is formed in the land and the data of the header area is formed. The disk circumferential position where the data of the non-common header area consisting of non-common data is arranged in the groove is different from the disk circumferential position where the data of the non-common header area is arranged in the land. It is a thing.

[0015]

Therefore, when reproducing the header area of the groove or land, since there is no signal component from the adjacent recording track, the data of the header area can be reproduced from the recording track being tracked without the influence of crosstalk. it can. Also, the data in the common header area can be obtained by the crosstalk component from the adjacent recording tracks.

[0016]

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

For example, in a phase change type optical disc, user data is recorded / reproduced in sector units of a predetermined data length, and an example of the format of the sector is shown in FIG. 4 (a).

In this case, one sector has a header area for storing identification information of the sector and a recording field (user data area) for storing user data.
Consists of.

As shown in FIG. 2B, the header area is composed of a predetermined data pattern and has a sector mark SM for detecting the beginning of a sector and a bit synchronization of the reproducing area of the header area. First bit sync signal V
FOa, a first address mark AM for establishing byte synchronization of the reproducing system in the header area, a first identification data ID composed of identification information such as a sector address, and bit synchronization of the reproducing system in the header area. Second identification data I including identification information such as a second bit synchronization signal VFOb for the purpose, a second address mark AM for establishing the byte synchronization of the reproduction system of the header area, and a sector address.
D, identification of a third bit sync signal VFOc for establishing bit synchronization of the reproduction system of the header area, third address mark AM for establishing byte synchronization of the reproduction system of the header area, sector address, etc. A third identification data ID including information and a preamble PA indicating the end of the header area are arranged.

FIG. 2A shows an arrangement example of the header area of the phase change type optical disk according to one embodiment of the present invention.

In the figure, lands L and grooves G are alternately formed in the recording area of the phase change type optical disk, the grooves G are formed in a groove shape, and the lands L are convex between the grooves. Formed as a strip-shaped portion. Here, the land L and the groove G are formed to have substantially the same radial dimension.

In the land L and the groove G, a land header area HL for a recording track of the land L,
The groove header areas HG for the recording tracks of the grooves G are alternately arranged in a manner that they do not overlap in the circumferential direction of the phase-change optical disk.

Here, each of the land header area HL and the groove header area HG is arranged by being divided into three parts, and these three land header areas HL and the groove header area HG constitute the data of the above-mentioned header area. .

Therefore, for example, when the land L is being tracked, the data of the land header area HL can be obtained by reproducing the data at the data reproduction timing shown in FIG.

Similarly, when the groove G is being tracked, the data is reproduced at the data reproduction timing as shown in FIG.
G data can be obtained.

In this way, in this embodiment, the land header areas HL and the groove header areas HG are alternately arranged in such a manner that they do not overlap with each other in the circumferential direction of the phase change type optical disk. Even if the laser beam (not shown) reaches the adjacent groove G during tracking, the laser beam does not detect the groove header region HG when the data is reproduced from the land header region HL. .

As a result, when the land L is being tracked, there is no influence of the crosstalk component from the groove header area HG, and as a result, the data in the header area can be properly reproduced from the land header area HL. .

Similarly, when the laser beam reaches the adjacent land L when tracking the groove G, the laser beam detects the land header area HL in the state where the data is reproduced from the groove header area HG. Therefore, when tracking the groove G, there is no influence of the crosstalk component from the land header area HL, and as a result, the data in the header area can be properly reproduced from the groove header area HG.

Therefore, in this embodiment, when the land L and the groove G are respectively tracked, the data in the proper header area can be obtained, and as a result, the data reproducing operation can be appropriately performed. You can

By the way, of the contents of the data in the header area of FIG. 1B, the contents other than the identification data ID are common to each sector. Therefore, the data of the common header area (hereinafter referred to as common header data) can be shared by the adjacent land L and groove G.

That is, as shown in FIG. 3A, the common header area HC in which the contents of the common header data are recorded is formed on the land L, and the data of the other header areas is
The land header areas HL and the groove header areas HG are arranged alternately in the circumferential direction.

In this case, when the land L is tracked, the data of the common header area HC and the land header area HL can be obtained by reproducing the data at the data reproduction timing as shown in FIG.

Similarly, when tracking the groove G, the data of the common header area HC and the groove header area HG can be obtained by reproducing the data at the data reproduction timing as shown in FIG. . However, in this case, the data reproduction from the common header area HC uses the crosstalk component from the adjacent land L.

FIG. 4A shows another embodiment of the header area.

In this case, the common header area HC in which the contents of the common header data are recorded is formed in the groove G, and the data in the other header areas is the land header areas HL and the grooves alternately arranged in the circumferential direction. Header area H
Place in G.

In this case, when the land L is tracked, the data of the common header area HC and the land header area HL can be obtained by reproducing the data at the data reproduction timing as shown in FIG. However, in this case, the data reproduction from the common header area HC uses the crosstalk component from the adjacent groove G.

Similarly, when tracking the groove G, the data of the common header area HC and the groove header area HG can be obtained by reproducing the data at the data reproduction timing as shown in FIG. .

By the way, in the above-mentioned embodiment, the case where the present invention is applied to the phase change type optical disk has been described.
The present invention can be similarly applied to a magneto-optical disk and the like.

[0039]

As described above, according to the present invention,
When reproducing the header area of the groove or land, since there is no signal component from the adjacent recording track, the data of the header area can be reproduced from the recording track being tracked without the influence of crosstalk. Further, there is an effect that the data in the common header area can be obtained by the crosstalk component from the adjacent recording tracks.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a sector format.

FIG. 2 is a schematic diagram showing a format of a header area according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a format of a header area according to another embodiment of the present invention.

FIG. 4 is a schematic diagram showing a format of a header area according to still another embodiment of the present invention.

FIG. 5 is a schematic partial perspective view showing a conventional example of a recording method in which a groove for guiding a laser beam is used as a data recording track together with a land.

[Explanation of symbols]

 L land G groove HL land header area HG groove header area HC common header area

Claims (3)

[Claims] 1. A user data area in which grooves and lands are alternately arranged and user data of a predetermined data length can be recorded, has a header of a predetermined data format for identifying each user data area at the beginning thereof. In the optical disc in which the areas are arranged, the groove and the land are used as data recording areas, respectively, and the header area formed in the groove and the header area formed in the land are displaced in the disc circumferential direction. An optical disc characterized in that it is arranged. 2. A header of a predetermined data format for identifying each user data area at the beginning of a user data area in which grooves and lands are alternately arranged and user data of a predetermined data length can be recorded. In the optical disc in which the areas are arranged, the groove and the land are used as data recording areas, respectively, and a common header area composed of common data of the data of the header area is formed in the groove and The position of the disk circumferential direction in which the data of the non-common header area consisting of the non-common data is arranged in the groove is different from the position of the disk circumferential direction in which the data of the non-common header area is arranged in the land. Optical disc. 3. A user data area in which grooves and lands are alternately arranged and user data of a predetermined data length can be recorded, has a header of a predetermined data format for identifying each user data area at the head thereof. In the optical disc in which the areas are arranged, the groove and the land are used as data recording areas, respectively, and the common header area composed of common data of the data of the header area is formed in the land and the data of the header area is The position of the disk circumferential direction in which the data of the non-common header area consisting of the non-common data is arranged in the groove is different from the position of the disk circumferential direction in which the data of the non-common header area is arranged in the land. Optical disc.