JPH02306430A - Correctable optical disk and recording and reproducing method - Google Patents

Abstract

PURPOSE:To allow the addition and correction of fixed information by constituting a reproduction only region of a recording medium the reflectivity of which can be changed by irradiation with a laser beam. CONSTITUTION:The pit information formed in the reproduction only region 1 is formed by using a material the reflectivity of which can be changed. For example, materials of a phase change type, such as indium antimony (In-Sb) and germanium tellurium antimony (Ge-Te-Sb) are used as the recording medium. The fixed information is previously formed by the presence and absence of pits formed by using the recording medium the reflectivity of which can be changed. The reflectivity of the recording medium is changed by irradiating only the sectors 3, 4 where the information is recorded when a change arises in a part of the fixed information. The addition or change of the fixed information is easily executed in this way.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to enable modification or addition of fixed information recorded in the read-only area with respect to an optical disc having a read-only area and a recordable area. A playback-only area (1) and a recordable area (2) in which fixed information is recorded.
Among the fixed information recorded in the read-only area (1) on an optical disc equipped with
3), (4)... while changing the reflectance of the beginning or the whole of..., sector (6) of recordable area (2), (
7) Record the change information in the playback-only area (1)
When reproducing the fixed information recorded in the recordable area (2), after reproducing the recorded information up to the sector (3) whose contents need to be changed, move the optical head to the sector (6) of the recordable area (2).
) to play back the changed information recorded in the sector (6), then return the optical head to the next position of the sector (3) in the read-only area (1) and play back the fixed information. After reproducing the recorded information up to the next sector (4) whose contents need to be changed, move the optical head again to the position of sector (7) in the recordable area (2) and repeat the same operation as before. By repeating this, a method for recording and reproducing a modifiable optical disc is constructed.

[Industrial application field]

The present invention relates to an optical disc having a read-only area and a recordable area.

Optical discs include compact discs (abbreviated as CDs), which have a reflective film made of a thin metal film on a disc-shaped resin substrate, and record information in the form of pits or not in tracks on the substrate. Dedicated memory (Re
It is called ad ONLY MEMORY (abbreviated as ROM).

There are also optical discs in which a recording film is formed on a substrate using a material that sublimes easily, such as tellurium (Te), information is formed in the form of pits on the recording film, and information is detected by the presence or absence of pits. Write-once memory
mory).

In addition, the recording film is formed of a magnetic film with perpendicular magnetization, and the rotation direction of polarized light differs depending on the magnetization direction, and the magneto-optical disk that records and reproduces information and changes in the reflectance of the recording film are used. There are phase change optical discs that record and reproduce information using rewritable memory (Eraser).
ble Memory).

As described above, there are various types of optical discs, but they can be broadly classified into read-only memories such as CDs, and recordable memories such as write-once memories and rewritable memories.

The present invention relates to an optical disc provided with both types of memory areas.

[Conventional technology]

As mentioned above, there are different types of optical discs, and depending on the purpose, a read-only memory or a recordable memory is used.

In these optical discs, the entire recordable area formed on the disk surface is used to configure read-only memory or recordable memory, and the read-only area and the recordable area are configured on the same surface. Optical discs equipped with this technology are not yet commercially available.

Due to the high recording density of optical discs, their use as large-capacity memories is increasing, but as a future trend, there will be demand for optical discs that have a recordable area in which users can write information in addition to a read-only area. is expected to increase.

For example, necessary items such as mathematical formulas are recorded in the read-only area, while it is convenient to perform necessary calculations using the recordable area and record the results.

[Problem to be solved by the invention]

As mentioned earlier, it is thought that optical discs with a read-only area and a recordable area on the same disc will be put into practical use in the future, but it will be difficult to add or correct the fixed information recorded in the read-only area. If necessary, conventional methods require the disk to be replaced.

However, it is uneconomical if only a few additions or modifications are required, and it would be extremely effective if conventional disks were utilized.

[Means to solve the problem]

The above problem is an optical disc that has a read-only area in which fixed information is recorded and a recordable area on the same disk, and the fixed information recorded in the read-only area must be changed in sectors that require changes. In addition to changing the reflectance at the beginning or the entire reflectance of the sector, change information is recorded in the sector of the recordable area, and when playing fixed information recorded in the playback-only area, the content must be changed. After playing back the recorded information of the sector,
After moving the optical head to a sector in the recordable area and reproducing the change information recorded in the sector, returning the optical head again to a position next to the sector in the read-only area;
After reproducing the fixed information and reproducing the recorded information of the next sector whose contents need to be changed, move the optical head again to the position of the sector in the recordable area and repeat the same operation to make corrections. This problem can be solved by configuring a recording and reproducing method for an optical disc that allows the recording and reproducing of optical discs.

[Effect]

In a read-only optical disk, as typified by a CD-ROM, fixed information is usually formed in the form of pits or not on tracks over which a metal film is formed.

However, in the optical disc according to the present invention, the pit information formed in the read-only area is formed using a material whose reflectance can be changed.

For example, the recording medium is made of indium aunchimon (In-
3b) and germanium tellurium antimony (Ge-T
Formed using a phase change material such as e-3b).

That is, in the former case, the reflectance differs depending on the crystal phase, and in the latter case, the reflectance differs between the amorphous state and the crystalline state.

The present invention uses such materials to construct a recording medium for a read-only area of an optical disc.

The optical disc according to the present invention is provided with a read-only area 1 and a recordable area 2 as shown in FIG.
The recording media constituting the two may be the same or different.

For example, the read-only area 1 may be formed of a phase change material such as In-3b, and the recordable area 2 may be formed of a perpendicularly magnetized film such as terbium-iron-cobalt (Tb-Fe-Co). However, it is advantageous to use the same material because it simplifies the manufacturing process of the optical disc and the recording and reproducing means.

Fixed information is formed using a recording medium whose reflectance can be changed in this way, depending on the presence or absence of pits, as in the past, and when a part of the fixed information changes, the sector in which that information is recorded is The reflectance of the recording medium is changed by irradiating only the areas 3 and 4 with laser light.

In this way, it is possible to easily detect a changed position when reproducing fixed information by irradiating a low-power laser beam.

Next, in the optical disc according to the present invention, this changed content is recorded in the recordable area 2, and as a method of doing so, an address table 5 is provided at the beginning of the recordable area 2 adjacent to the read-only area 1, The address of sector 3.4 in the read-only area whose contents are to be changed and the address of sector 6.7 in which the changed contents are to be newly recorded in recordable area 2 are recorded here.

Then, the changed contents are recorded in the sector 6.7 of the address position of the recordable area 2 recorded here.

Next, the reproduction operation of such a modifiable optical disc is as follows.

FIG. 2 is a diagram showing the driving method of the fixed information reproducing circuit 9. Recordable area reproduction circuit 10° reflectance detection circuit 11. Laser control circuit 12. Servo system drive circuit 13
etc. are controlled by the control circuit 14.

At the knee, the fixed information reproducing circuit 9 is connected to the recordable area reproducing circuit 1.
The difference from 0 is that the recordable area is Tb-Fe-C.

This is because there are cases where the recording medium is composed of a recording medium that uses a different detection method, such as when it is composed of a film.

Next, the reflectance detection circuit 11 detects sectors that require addition or modification by detecting the level of reflected light, separately from the fixed information reproducing circuit 9 that reproduces information depending on the presence or absence of pits.

Further, when recording information, the laser control circuit 12
Optical head 1 emits a high-power laser beam that is intermittently turned on and off.
This circuit emits light from the laser beam 5 to the track of the optical disk, and scans a low-output laser beam during reproduction.

In addition, the servo system drive circuit 13 directs the laser beam from the read-only area 1 to the address table 5, and from the address table 5 to the address table 5.
This is a circuit for moving the stage 16 from the recordable area 2 to the recordable area 2.

Now, the reproduction operation according to the present invention will be explained as follows.

To reproduce the fixed information recorded in the reproduction-only area 1, the stage 16 is moved by the servo drive circuit 13 controlled by the control circuit 14, as shown in FIG.
The laser control circuit 12 sends a continuous low-output laser beam to the read-only area 1 of the optical disc 17 using the optical head 15.
The fixed information reproducing circuit 9 reproduces the pit information.

When the laser beam emitted from the optical head 15 reaches a sector where information needs to be corrected or added, the reflectance of that part is different, so the reflectance detection circuit 1
1 detects this and immediately operates the servo system drive circuit 13 to move the stage 16 so that the laser beam scans the address table 5. When the address written there is read, the servo system drive circuit 13 operates. In operation, the laser beam flies to the address position in the recordable area 2 and reproduces corrected or additional information.

When the reproduction of the specified address position is completed, the stage 16 is moved by the servo drive circuit 13, and the laser beam moves to the next sector position of the reproduction-only area 1 where the information was previously reproduced, and the fixed information is reproduced. Continue.

By using such a method, fixed information can be easily added or changed.

〔Example〕

Example 1: 100 Mbytes of data was edited in accordance with the CD-ROM format and stored on a magnetic disk.

Then, as in the past, the old CD-RO name was reproduced from a magnetic disk, and the rotating photoresist-coated glass substrate was irradiated with laser light while modulating it in pulses.
Fixed information consisting of (Identification) information and data was recorded on the inner circumference.

In this embodiment, the number of sectors is approximately 20 o, o
There are oo sectors, and each sector consists of 2048 bytes of user data.

Next, the recordable area at the outer periphery was irradiated with laser light to record pre-groups (guide grooves) and ID information in the same manner as in the past, and developed to create a resist master.

Next, after electroforming nickel (Ni) on the surface of the resist master, it was peeled off to make a stamper, and polycarbonate (abbreviated as PC) was injection molded using this to make an outer diameter of 120 mm.
A disk substrate with an inner diameter of 15 mm and a thickness of 1.2 mm was made.

The disk substrate was placed in a vacuum evaporation device, and a silicon dioxide (SiO□) film with a thickness of 10 nm was deposited as an underlayer film, and indium antimony (InSb) was deposited with a thickness of 50 nm as a recording film.
It was formed to a thickness of nm, and an ultraviolet curing resin was applied thereon and cured to form an optical disk.

When this disc was loaded into a commercially available CD-ROM player and information was reproduced, there was no problem in reproducing information.

Next, as a method for correcting the information recorded in the read-only area, first, in order to correct the information in the 1000th sector, this sector was irradiated with a strong laser beam of 4 mW.

As a result, the reflectance of this sector was increased by 1.5 times that of the conventional one.

Note that the laser power applied during reproduction is 1 mW or less.

Next, the modified information was recorded in the recordable area, and then the address of the modified fixed information, that is, the track number, the sector number, and the address of the modified information recorded in the recordable area were recorded in the address table.

In this way, even if it is necessary to change the ROM information, the existing optical disc can be used as is.

Example 2: Using the same PC board as in Example 1, the same In-3b alloy thin film as in Example 1 was formed in the read-only area, while terbium (Tb) and terbium (Tb) were formed in the recordable area by sputtering. S
A base layer consisting of a mixed layer of iO□ is formed to a thickness of loonm,
A recording layer made of terbium-iron-cobalt (TbFeCo) was made to a thickness of 1100 nm, and an ultraviolet curable resin was applied thereon and cured to form a protective film to produce a magneto-optical disk.

Next, in order to modify the information on the 1000th sector in the read-only area as in the first embodiment, this sector is
After irradiating a strong mW laser beam to improve the reflectance, and then recording the correction information within the recordable area, the address of the fixed information that has been corrected in the address table and the change information recorded in the recordable area are recorded. I recorded the address.

When this optical disk was installed in a player that could play back CD-ROMs and was also capable of recording and playing back magneto-optical disks and played back fixed information, no problems occurred.100
I was able to reproduce the modified information for the 0th sector.

〔Effect of the invention〕

As described above, according to the present invention, even if it becomes necessary to add, modify, or change playback-only fixed information, the correction can be made without creating a new master disc, making optical discs economical and convenient. It can be used for.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of an optical disc showing a method of implementing the present invention. In the figure, 1 is a playback-only area, 2 is a recordable area, and 3.4
, 6.7 is a sector, 5 is an address table, 9 is a fixed information reproducing circuit, 10 is a recordable area reproducing circuit, 11 is a reflectance detection circuit, and 14 is a control circuit. 〉

Claims (1)

[Scope of Claims] [1] In an optical disc comprising a read-only area (1) in which fixed information is recorded and a recordable area (2) within the same disc, the read-only area (1) is irradiated with laser light. A modifiable optical disc comprising a recording medium whose reflectance can be changed. [2] In an optical disc equipped with a read-only area (1) and a recordable area (2) in which fixed information is recorded within the same disc, the content of the fixed information recorded in the read-only area (1) is Sectors (3) and (4) that require changes to
For..., the reflectance of the beginning or the entire sector (3), (4)... is changed, and the recordable area (2) is changed.
) in sectors (6), (7)..., and when reproducing the fixed information recorded in the reproduction-only area (1), the sector (3) whose contents need to be changed.
After reproducing up to the recorded information, move the optical head to sector (6) of recordable area (2) and read the recorded information in sector (6).
After reproducing the change information recorded in the , the optical head is returned to the position next to the sector (3) in the read-only area (1), the fixed information is reproduced, and the next time the content needs to be changed. After reproducing the recorded information up to sector (4), the optical head is moved again to the position of sector (7) of recordable area (2) and the same operation is repeated. Recording and playback method.