JPS615442A - Optical disk - Google Patents

Abstract

PURPOSE:To use an optical disk whose track areas can be identified by reproducing information signals for identifying areas with an optical head and in which track areas of reproduction only, postscript only, etc., are mixedly provided, by previously providing the area identifying information signals on part of the track as pits. CONSTITUTION:Annular areas represented by RA, RB, and RC are used as a track area for postscript, area for reproduction only, and area for erasion, respectively. An index field 3 is composed of an index mark 4 and jumping area 5. Each sector 6 has a sector header area 7 followed by a data field (D0-Dn)8 in which recorded data are accumulated at the first section. The index mark 4 of the index field 3 retraces the same track at every turn. It can be discriminated by detecting the reproducing signal of an area identifying signal section 9 that which kind of track area of this optical disk is reproduced and, when the postscript type track area is reproduced, suitable measures and control, such as inhibition of irradiation of an earsing light beam, for performing the recording and reproduction of the postscript type optical disk are performed. Therefore, this optical disk can be operated with one set of optical disk device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical disc used in an optical disc device that reproduces, records, or reproduces information signals such as digital data by narrowing a laser beam to a finely focused laser beam.

Conventional configuration and its problems Optical discs are created by concentrating laser light into a minute light spot with a diameter of approximately 1 μm. Since signals can be recorded and reproduced, the recording density is high and the memory cost per bit is low.
It is attracting attention as a high-density, large-capacity digital memory because of its high-speed access and non-contact recording and reproducing capabilities.

Optical disks used as memory can be roughly classified into three types.

One of them is Digital Audio Disc (DAD).
This is a read-only optical disc in which information signals are provided in advance as pit train tracks on the optical disc. 2
The first is a write-once optical disc, which allows one-time recording by punching holes in the recording layer using the thermal energy of a laser beam or by locally changing the optical density of the recording layer. It is suitable for use as a long-term storage optical disc that can be recorded and played back by the user.

The other type is a rewritable or erasable optical disc.
There are devices that use the thermal energy of a laser to reversibly change the optical density of the recording layer, and optical disk devices use an erasing light beam separate from the recording and reproducing light beam to obtain erasing under suitable erasing conditions. is proposed. By the way, 1
With one optical disk device, without changing the device conditions,
It can be said that it is actually extremely difficult to use the above three types of optical discs. For example, an erase bar is used on a write-once optical disc.
There is a risk of erroneous recording when irradiated with an erasing light beam that has a power, or that in order to obtain a high-quality reproduction signal, it is necessary to control the power of the light beam irradiated to the optical disc, or control such as focus and tracking. It is necessary to vary the gain, and this is necessary because the recording light beam power drop and the reflectance of the optical disc differ depending on the type of optical disc.

Therefore, it is also possible to set the optical disk device each time the user gas is used depending on the optical disk being used, such as prohibiting irradiation of the erasing light beam onto a write-once optical disk, controlling the laser beam such as the irradiation light power, and switching the control gain. However, it is very inconvenient to use.

As a way to solve this problem, the optical disc is stored in a cartridge, and a hole is provided for identifying the disc using light that differs depending on the type of optical disc stored in the cartridge.This hole is detected by a sensor installed in the optical disc device. Based on the identification result, the optical disc adjusting device automatically controls the laser beam and changes the control gain as described above to achieve a state suitable for the loaded optical disc. A method has been proposed.

On the other hand, one optical disc has at least two, and in some cases three, track areas: a track area with the same quality as a read-only optical disc, a track area with the same quality as a write-once optical disc, and a track area with the same quality as an erasable optical disc. Optical discs have very high utility value depending on the purpose of use.

However, for optical discs with a mixture of different track areas, the above-mentioned method in which the user makes adjustments each time or the method using a combination of a cartridge and a sensor are methodologically possible, but are extremely difficult to put into practical use.

Purpose of the Invention The present invention has been made in view of the above-mentioned points, and even if different track areas coexist on one optical disc,
It is an object of the present invention to provide an optical disc whose track area can be easily identified.

Structure of the Invention The optical disk of the present invention has spiral or concentric tracks, and at least two areas, a read-only track area, a write-once track area, and an erasable track area, are provided in one optical disk. The above object is achieved by providing a region identification signal, which is the same in the same track region and different from other track regions, in advance on the track in the form of optically detectable irregularities.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is an external view showing an outline of the disc format of an optical disc according to an embodiment of the present invention.

Tracks on an optical disk are formed in a spiral or concentric shape, but in the following explanation, it is assumed that they are formed in a spiral shape. In this embodiment, the center hole 2 for driving at a constant rotation speed in the direction of arrow R
has.

The annular areas in the disk radial direction denoted by RA, RB, and Rc are here a write-once type track area, a read-only type track area, and an erasing type track area, respectively.

The write-once type track area RA indicates that only the above-mentioned recording is possible on this track, and a C recording layer is provided on this track so that recording and reproduction is possible. The erase type track area RC is also used for the same purpose.

This is a 3Fi index field.

The index field 3 is composed of an index mark 4 and a jumping area 6.

6 is a sector, and one track has sectors from 80 to Sn (n+1
) has equally spaced sectors.

One track in a circular track has a track length equivalent to one revolution of the disk.

Each sector 6 has a sector header area 7 at the beginning,
Data fields (D0 to Dn) for recording data after that or for accumulating already recorded data
It has 8.

The sector header area 7 includes an area identification signal section 9. Sector mark 10. It consists of address fields (Ao-An) 11.

The index mark 4 of the index field 3 is used as a track jumping start signal for always retracing the same track by going back or forward one track each time the optical disk rotates. By driving the aperture lens of the optical head by an amount equivalent to the track pitch in a direction perpendicular to the track using an index signal detected from a reproduction signal reproduced by an optical head provided in an optical disk device (not shown), the track can be tracked within the jumping area 6. Jump back to the original track. Whether or not track jumping has been performed correctly is determined by the address field 11 following the jumping area 6. Read and confirm Ao.

The area identification signal section 9 includes a read-only track area RB.
, write-once type track area RA, erasing type track area RA.
1971 gkli RCK Oi-C4-0) 2
y19J4tltT' is the same, but different signals are provided as uneven pits to be described later in other different areas.

Therefore, even if a large disc has different track areas mixed together, it is possible to identify which type of track area has been modified by reproducing the area identification signal part 9 with an optical head and detecting the reproduced signal. This can be done by The optical disc device detects the playback signal of the area identification signal unit 9, and can identify from the detection signal what type of track area is being played back on the loaded optical disc. If the track area is , appropriate measures and controls for recording and reproducing the write-once optical disc are performed, such as prohibiting the irradiation of the erasing light beam.

The address field 11 contains a preamble for clock synchronization for clock reproduction, an address mark for detecting the start of an address, and a track address assigned to each track.

Each sector has one sector address assigned,
Furthermore, the sector mark 10 is used to provide a higher detection ability for sector addresses, but the details thereof will be omitted.

Next, the disk structure will be explained according to FIG. FIG. 2 is a conceptual perspective view partially showing the radial direction of the optical disc in cross section.

In write-once type, erasing type and track areas, grooved tracks with grooves on the entire recording/reproducing area on the optical disk are used as optical guide tracks, and in read-only type/track areas, the track structure has data in advance in the data field. I have to.

In the figure, the RA area, write-once type or erasing type area indicates a data field 8, and preformatted areas such as the θB area identification signal portion 9 and index mark 4 are shown.

In the figure, the base material 12 is made of a transparent or semi-transparent material. The RA area track 13 has a width W and a depth d.

A continuous spiral track 13 is formed by the groove 14 of the track big p and the uneven pit row 16.

A recording thin film 16 having a thickness t is formed on the track 13 by a method such as vapor deposition, and a protective layer 17 is provided thereon. The depth d9 and width W of the groove 14 are set 4 so that it functions as an optically detectable track.

By irradiating the groove 14 with a finely focused light beam 17, data recording, reproduction, etc. are performed. 18 indicates a focus point where an optical density change has occurred.

Signals to be formatted on the optical disc in advance, such as the area identification signal part 9, are provided with a necessary length as a bit string 15' having an optically detectable uneven structure.

The track of the RB area reproduction-only track area is shown, and in the θA area, that is, the data field 9, the data to be reproduced is preliminarily set as a focus line with an optically detectable uneven structure like track 13'. Alternatively, data to be reproduced may be further provided as a bit string with a concave-convex structure in a groove 14' similar to the groove 14 in area A, as shown by track 13''. The vapor deposited film in the track area may be the same as the recording thin film 17 described above, but in order to improve the reproduction signal quality, it is preferable to vapor deposit a thin Al film.

FIG. 3 is an external view schematically showing the disc format of an optical disc according to another embodiment of the present invention.

Components that are considered to be the same as those explained in FIG. 1 are given the same reference numerals.

The optical disk according to the embodiment shown in FIG. 3 has a smaller data capacity than the one shown in FIG. 1, but the optical disk can be manufactured more easily.

As shown in FIG. 3, a boundary track area RD is provided at the boundary between different track areas, a write-once type track area RA and a read-only type track area RB.

A boundary track area RD is provided between a read-only track area RB and an erase-type track area RC.

The boundary track area Rp connects the different track areas mentioned above at a continuous track pitch.

In the embodiments shown in FIGS. 1 and 3, an area identification signal is provided for each header area of each sector.
``This has the advantage that the reliability of identification is increased because the track area can be identified for each sector, which is the smallest unit in which data is recorded and reproduced, and the waiting time for disk rotation for identification is reduced. There is. However, it goes without saying that the gist of the present invention does not depart from the spirit of the present invention by providing one location per track, for example, immediately before the index mark.

12' is a base material already provided with tracks formed in a spiral shape. A write-once recording thin film 16' is first deposited in an area wider in the disk radial direction than the write-once track area. A deposited film 16'' such as A1 is also deposited on the read-only track area RB in an area wider than RB, and an erasable recording thin film 16'' is similarly deposited on the erasable track area RC.

The boundary area between different track areas, which is deposited outside the respective track areas of Rp, 'RB, and RC, is the boundary track area RD. Often a mixture of both. Therefore, although the boundary track area RD is optically effective as described above, it is an invalid area in terms of data storage capacity. In disk manufacturing, a desired track area RA can be achieved even if there is disk eccentricity or the mask position during deposition of a recording thin film or vapor deposition film does not have to be highly accurate.

RB and RC are obtained, making it easy to manufacture optical discs.

Effects of the Invention The optical disk of the present invention has a track formed in a spiral or concentric pattern, and has a structure in which an information signal for area identification is provided in advance as pits in the form of convexes and convexes in a part of the track. Since the above-mentioned signal is reproduced by the head and the identification of the above-mentioned area can be detected from the reproduced signal, a special detection sensor for identification is not required.
A playback-only type with different conditions such as disc irradiation light power.

Its practical value is great, as it allows optical discs with a mix of recordable and erasable track areas to be used in a single optical disc device without any adjustment by the user.

[Brief explanation of drawings]

FIG. 1 is a plan view of an optical disk according to an embodiment of the present invention, and FIG.
3 is a plan view of an optical disk according to another embodiment of the present invention, and FIG. 4 is a sectional view for explaining the track area. . 1...Optical disc, RA, RB, Rc
...Track area, RD...Boundary track area, 6...Sector, 7...Sector header area, 9...Area identification signal . Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 13'' Rs R4 ←--←-1 Figure 3 Figure 4

Claims (4)

[Claims] (1) An optical disc having spiral or concentric tracks, in which at least two different tracks among a read-only track area, a write-once track area, and an erasing track area are arranged annularly in the radial direction of the disc. 1. An optical disc characterized in that an area identification signal, which is the same in the same track area and different from other track areas, is provided in advance on the track in the form of optically detectable unevenness. . (2) There is a boundary track area at the boundary between different track areas, and a boundary area identification signal different from the read-only type, write-once type, and erase type track areas is in the form of optically detectable unevenness. The optical disc according to claim 1, wherein the optical disc is provided in advance in a track in a boundary track area. (3) A patent claim characterized in that a track area identification signal or a boundary track identification signal is provided at one location in at least one track of a read-only type, a write-once type, and an erase type track area or a boundary track area, respectively. The optical disc according to item 1 or 2 of the range. (4) The track is provided with a sector having a sector header area and a data field in the disk rotation direction, and an area identification signal and a boundary area identification signal are provided in the sector header area. Range 1
2. The optical disc according to item 2 or item 2.