JPH0773508A - Optical recording medium and its recording and reproducing method - Google Patents

Abstract

PURPOSE:To provide an optical recording medium in which high density recording are reproducing of information are performed in a high speed and the method for recording and reproducing. CONSTITUTION:In the optical recording medium, information tracks are provided on the surface of a transparent substrate 1 with alternatively varying heights. Projecting and recessed parts for address recognition are formed in a first block of odd number higher height tracks by varying track widths and in a second block of even number higher height tracks, projecting and recessed parts are formed by varying track widths. Addresses of odd number higher height tracks are recognized from the first block. Addresses of even number higher height tracks are recognized from the second block. Moreover, addresses of lower height tracks are recognized from the first and the second blocks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium for recording / reproducing information with a laser beam and a recording / reproducing method thereof, and more particularly to an additional recordable (including rewritable) optical recording having information tracks of different heights. The present invention relates to a medium and a recording / reproducing method thereof.

[0002]

2. Description of the Related Art An optical disk or the like for recording or reproducing information by laser light has a high recording density and thus has an excellent feature as a mass storage system.

In such an optical disc or the like, a track of about 1 μm is provided spirally or concentrically on an optical recording medium in order to record information at a high density, and recording or reproduction is performed with a laser beam narrowed down. At this time, track servo is performed so that the laser beam does not deviate from a desired track and go to other tracks. Further, in order to record or reproduce information at a high speed, a concavo-convex pre-format for address identification is formed on each track for each unit information section. (For example, Japanese Patent Application Laid-Open Nos. 1-165052 and 4-172623).

FIG. 7 shows a conventional ISO (International Orga
nization for Standardization) compliant 130 mm magneto-optical type optical disc as an optical recording medium partially enlarged view,
(A) is a plan view and (b) is a sectional view.

In the figure, a land portion 101 which is an information track 100 is divided by a V-shaped groove portion 102, and a pit 103 which is an unevenness for address identification is formed in each unit information section in the land portion 101. .

FIG. 8 is a partially enlarged view of another conventional optical recording medium, (a) is a plan view and (b) is a sectional view. In the figure, the land portion 111, which is the information track 110, is divided by a U-shaped groove portion 112.
In the unit, a bent portion 113 of the wall surface is formed as an unevenness for address identification for each unit information section.

Such unevenness is formed on a transparent substrate, and a recording film is formed on this transparent substrate.

Generally, the recording film of an optical recording medium such as a recordable optical disk is a magneto-optical type utilizing the Kerr effect, or a phase change type utilizing the difference in reflectance between crystalline and amorphous. Is used.

Laser light for recording and reproduction enters through a transparent substrate and has a diameter of about 1.4 μm near the recording film.
Is focused by the focus servo so that As the laser light source, a semiconductor laser having a wavelength of about 6700 to 8300 Å is used.

Information is recorded by irradiating a laser beam of high power corresponding to the information so that the recording film absorbs the energy of the laser beam and converts it into heat energy to raise the temperature of the recording film. In the magneto-optical type, information is recorded by applying a recording bias magnetic field to a region including this portion and orienting the magnetization of this portion in a direction opposite to that of the other portions. The phase change type is
Information is recorded by rapidly cooling this temperature-rising portion by stopping the laser light irradiation to change this portion from crystalline to amorphous.

To read information, a low power laser beam is irradiated along the information track to detect a difference in the amount of reflected light due to a difference in the state of the recording film as a signal. The magneto-optical type utilizes the fact that when the recording film is irradiated with a linearly polarized laser beam, the polarization plane of the reflected light from the recording film rotates depending on the magnetization direction. The phase change type utilizes the fact that the reflectance in the crystalline state and the reflectance in the amorphous state are different.

Since such a magneto-optical film and a phase change film are easily oxidized, they are usually sandwiched between dielectric films.

Next, a recording / reproducing method for such an optical recording medium will be described.

When information is recorded or reproduced, the information track is irradiated with a laser beam of low power, and the address identification unevenness is formed in each unit information section of the information track. Is recognized, and the recording / reproducing described above is performed.

On the other hand, as a method for recording and reproducing at high density,
A method has also been proposed in which information tracks are alternately provided with different heights (for example, Japanese Patent Laid-Open No. 2-58732).

[0016]

However, in the above-mentioned conventional optical recording medium and the recording / reproducing method thereof, there is no problem that information can be recorded at high density and the recording / reproducing of information can be performed at high speed. there were.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical recording medium capable of recording / reproducing information at high density and at high speed, and a recording / reproducing method thereof.

[0018]

In the optical recording medium of the present invention, tracks for recording information are alternately provided on the surface of a transparent substrate at different heights, and the tracks for address identification are provided for each unit information section. Is a recordable optical recording medium in which a concavo-convex pre-format is formed, and the odd-numbered tracks of the high-altitude tracks [or the low-altitude tracks] have a track width in the first block of each unit information section. To form an unevenness for address identification, and to change the track width to the second block of each unit information section in the even-numbered tracks of the high-altitude track [or the low-altitude track]. It is configured so as to form unevenness for identification.

In the optical recording medium of the present invention, at least the first dielectric film, the phase change film, the second dielectric film and the metal film are laminated on the transparent substrate of the optical recording medium of the first invention. To configure.

In the recording / reproducing method for the optical recording medium of the fifth aspect of the present invention, tracks for recording information are alternately provided on the surface of the transparent substrate at different heights, and the high-side tracks [or the low-side tracks are provided. Unevenness for address identification is formed in the first block of each unit information section by changing the track width in the odd-numbered tracks of [Track], and in the even-numbered tracks of the high-altitude tracks [or low-altitude tracks] An optical recording medium in which unevenness for address identification is formed by changing the track width in the second block of each unit information section is used, and information is recorded in an odd number track of the high place track [or the low place track]. When recording or reproducing the information, the address is recognized from the unevenness for identifying the address of the first block,
When information is recorded on or reproduced from even tracks of the high-altitude track [or the low-altitude track],
The address is recognized from the unevenness for identifying the address of the second block, and the low place track [or the high place track]
When recording or playing back information on
The address is controlled so as to be recognized from the unevenness for identifying the address of the first block and the unevenness for identifying the address of the second block.

[0021]

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

FIG. 1 is a partially enlarged explanatory view of the preformat of the optical recording medium of the present invention, (a) is a plan view and (b) is a plan view.
FIG. 2 is a sectional view showing a schematic flow chart for explaining the address of each track in the recording and reproduction.

On the surface of the transparent substrate 1, high-place tracks (L2m-1, L2m, etc.) and low-place tracks (Gn, etc.) are alternately provided as tracks for recording information. The addressed part of each block has a first block and a second block which are continuous with each other, and 4 bits are recorded in the first block and 4 bits are recorded in the second block. The first block and the second block are unit information sections of the track, and the address bits of each block are present in the section.

In the low-altitude track, both the first and second tracks are used for addressing, and the address codes 1 and 0 are recorded depending on whether or not wide bends are provided at regular intervals on the track wall. Has been done. For example, the address of the low place track Gn-1 is (A1, A2, A
3, A4, K1, K2, K3, K4), low-place truck G
The address of n is (A1, A2, A3, A4, B1, B
2, B3, B4) are each 8 bits. In addition, there are the following conditions in the arrangement of the bent portion of the address of the low-place track. That is, in the first block, the address code and position change every two tracks, and in the second block, the address code and position also change every two tracks, but the change is shifted by one track from the first block.

On the other hand, of the high-altitude tracks, odd high-altitude tracks (L2m-1, L2m + 1, etc.) are addressed to the first block, and even high-altitude tracks (L2m-2, L2m, etc.) are second.
Addresses are assigned to blocks, and the codes 1 and 0 of the respective addresses are recorded depending on whether or not a narrow bent portion is provided at regular intervals on the track wall.
Therefore, the addresses of the high and even tracks are 4 bits. Further, the address of the high-place odd track is the same as the address of the first block part of the adjacent low-place track, and the high-even number track is the same as the address of the second block part of the adjacent low-place track. .

Next, an address detecting method will be described with reference to FIG.

First, the distinction between the high-altitude track and the low-altitude track is judged by the polarity of the push-pull signal obtained from the photodetector when the laser light crosses the wall surface of the track boundary. Here, when it is determined that the track is the high-altitude track and the laser light is scanned in the length direction of the track, addresses of only 4 bits (for example, A1 to A4 or C1 to C4) are detected in the first block. Occasionally, the address is identified as a high-place odd address, and an address in which addresses A1 to A4 and C1 to C4 (or a combination of other addresses) are mixed is detected in the first block, and when a 4-bit address cannot be detected, a high address is detected. As an even-numbered track, no address is detected in the first block, and a 4-bit address is detected in the second block of the same track. After distinguishing the high place track and the low place track, if it is determined that the track is the low place track, an 8-bit address is detected in the first and second blocks.

As described above, the addressing is performed for each track and the address is detected.

When the address signal is subjected to the bi-phase modulation, the continuous carrier waves at the high-numbered odd track numbers are alternately in the opposite phase, and the continuous carrier waves at the high-numbered even track numbers are also in the opposite phase. Since the amplitudes of the address identification signals in the first block on the even-numbered tracks are canceled and are small, it is possible to immediately determine that the even-numbered tracks.

The above-mentioned roles of the high-altitude track and the low-altitude track may be reversed depending on the method of manufacturing the stamper for forming the preformat, but here, the light of the master exposure machine for manufacturing the stamper is used. The case where the beam is irradiated onto a low-lying track is described.

FIG. 3 is a schematic sectional view showing the basic structure of the film structure of an embodiment of the optical recording medium of the present invention.

In the optical recording medium shown in FIG. 3, a first dielectric film 21 is provided on the transparent substrate 1 shown in FIG. 1, a magneto-optical film 22 is provided thereon, and a second dielectric film 22 is provided thereon. The body membrane 23 is provided in order.

FIG. 4 is a schematic sectional view showing the basic constitution of the film constitution of another embodiment of the optical recording medium of the present invention.

In the optical recording medium shown in FIG. 4, a first dielectric film 31 is provided on the transparent substrate 1 shown in FIG. 1, a magneto-optical film 32 is provided thereon, and a second dielectric film 32 is provided thereon. The body film 33 is provided, and the metal film 34 is sequentially provided on the body film 33.

FIG. 5 is a schematic sectional view showing the basic structure of the film structure of another embodiment of the optical recording medium of the present invention.

In the optical recording medium shown in FIG. 5, a first dielectric film 41 is provided on the transparent substrate 1 shown in FIG. 1, a phase change film 42 is provided thereon, and a second dielectric film is provided thereon. The body membrane 43 is provided in order.

FIG. 6 is a schematic sectional view showing the basic structure of the film structure of another embodiment of the optical recording medium of the present invention.

In the optical recording medium shown in FIG. 6, a first dielectric film 51 is provided on the transparent substrate 1 shown in FIG. 1, a phase change film 52 is provided thereon, and a second dielectric film 52 is provided thereon. The body film 53 is provided, and the metal film 54 is sequentially provided on the body film 53.

Information may be recorded and reproduced by injecting a laser beam through the transparent substrate 1 with these optical recording media having the configurations shown in FIGS. A protective film such as resin may be provided. In addition, a hot-melting agent may be applied onto a protective film such as a UV curable resin to bond the two optical recording media so that the transparent substrate faces outside.

Furthermore, when an antireflection film such as SiO2, a surface-hardened film of a transparent organic resin having high hardness, or a transparent film having high conductivity is provided on the transparent substrate 1 on the side opposite to the recording film. There is also.

As the transparent substrate 1, a polycarbonate resin plate, a polyolefin resin plate, an acrylic resin plate,
A glass plate, an acrylic resin plate with a photopolymer, or a glass plate with a photopolymer is used. The preformat mentioned above is formed on the plate itself or on the surface of the photopolymer. The pitch of the information tracks is approximately 0.5-1.4 μm.

The materials for the first dielectric films 21 and 31 are mainly composed of silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, hydrogenated silicon carbide, and tantalum oxide. Especially desirable.

The material of the first dielectric films 41 and 51 is a mixture of zinc sulfide and silicon dioxide, silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, hydrogenated silicon carbide, or the like. , It is especially desirable to use tantalum oxide as the main component.

The material of the magneto-optical films 22 and 32 is Tb.
Fe, TbFeCo, TbFeTi, TbFeC
oTi, TbFeCr, TbFeCoCr, Tb
FeTa, TbFeCoTa, TbFeNiCr
, TbFeCoNiCr, TbGdFe, TbG
dFeCo, TbGdFeTi, TbGdFeCo
Ti, TbGdFeCr, TbGdFeCoCr
, TbGdFeTa, TbGdFeCoTa, T
bGdFeNiCr, TbGdFeCoNiCr,
TbDyFe, TbDyFeCo, TbDyFeT
i, TbDyFeCoTi, TbDyFeCr,
TbDyFeCoCr, TbDyFeTa, TbD
yFeCoTa, TbDyFeNiCr, TbDy
FeCoNiCr, TbGdNdFe, TbGdN
dFeCo, TbGdNdFeTi, TbGdNd
FeCoTi, TbGdNdFeCr, TbGdN
dFeCoCr, TbGdNdFeTa, TbGd
NdFeCoTa, TbGdNdFeNiCr, T
bGdNdFeCoNiCr, TbGdDyFe,
TbGdDyFeCo, TbGdDyFeTi, T
bGdDyFeCoTi, TbGdDyFeCr,
TbGdDyFeCoCr and TbGdDyFeTa
, TbGdDyFeCoTa, TbGdDyFeN
iCr and TbGdDyFeCoNiCr are particularly desirable. Further, a plurality of other layers may be stacked on these layers.
In addition, GdFe, GdFeCo, GdFeTi,
GdFeCoTi, GdFeCr, GdFeCoC
r, GdFeTa, GdFeCoTa, GdFe
NiCr, GdFeCoNiCr, GdNdFe
, GdNdFeCo, GdNdFeTi, GdN
dFeCoTi, GdNdFeCr, GdNdFe
CoCr, GdNdFeTa, GdNdFeCoT
a, GdNdFeNiCr, GdNdFeCoNi
Read-out layers such as Cr may be stacked.

As a material for the phase change films 42 and 52, a compound of a chalcogen element is desirable, and GeSbTe is particularly desirable. A small amount of element such as nitrogen may be added to the phase change films 42 and 52.

The materials for the second dielectric films 23 and 33 are mainly composed of silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, hydrogenated silicon carbide, and tantalum oxide. Especially desirable.

The material of the second dielectric films 43 and 53 is a mixture of zinc sulfide and silicon dioxide, silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, hydrogenated silicon carbide, or the like. , It is especially desirable to use tantalum oxide as the main component.

An aluminum alloy is desirable as a material for the metal films 34 and 54. Additional elements include Ti and C
Particularly preferred are r, Ta, Ni, and NiCr.

Laser light for recording and reproduction enters through the transparent substrate 1 and is about φ1.0 to φ near the recording film.
Focusing servo is used to focus light to 1.4 μm. The wavelength of the laser light source is 6500-830
A semiconductor laser of about 0 Å is used.

[0050]

The optical recording medium and the recording / reproducing method thereof according to the present invention have an effect that information can be recorded / reproduced at a high density and at a high speed.

[Brief description of drawings]

FIG. 1 is a partially enlarged explanatory view of a preformat of an optical recording medium of the present invention,

FIG. 2 is a flowchart showing an address recording / reproducing method of the optical recording medium of the present invention.

FIG. 3 is a plan view showing a basic structure of an optical recording medium according to an embodiment of the present invention,

FIG. 4 is a plan view showing the basic structure of an optical recording medium according to another embodiment of the present invention,

FIG. 5 is a plan view showing the basic structure of an optical recording medium according to another embodiment of the present invention,

FIG. 6 is a plan view showing the basic structure of an optical recording medium according to another embodiment of the present invention,

FIG. 7 is a partially enlarged explanatory view of a preformat of a conventional optical recording medium,

FIG. 8 is a partially enlarged explanatory diagram of a preformat of a conventional optical recording medium.

[Explanation of symbols]

 1 Transparent Substrate 21, 31, 41, 51 First Dielectric Film 22, 32 Magneto-Optical Film 23, 33, 43, 53 Second Dielectric Film 34, 54 Metal Film 100, 110 Information Track 101, 111 Land Part 102 V-shaped groove portion 103 Pit 112 U-shaped groove portion 113 Bent portion of wall surface

Claims (6)

[Claims] 1. A track for recording information is provided alternately on the surface of a transparent substrate at different heights, and a concavo-convex pre-format for address identification is formed for each unit information section on the track. In this optical recording medium, unevenness for address identification is formed in the first block of each unit information section in the odd numbered tracks of the high-altitude track [or low-altitude track] by changing the track width. An optical recording medium characterized in that on an even-numbered track of a high-altitude track [or low-altitude track], an unevenness for address identification is formed in the second block for each unit information section by changing the track width. . 2. The optical recording medium according to claim 1, wherein at least a first dielectric film, a magneto-optical film, and a second dielectric film are laminated on the transparent substrate. 3. The optical recording according to claim 1, wherein at least a first dielectric film, a magneto-optical film, a second dielectric film, and a metal film are laminated on the transparent substrate. Medium. 4. The optical recording medium according to claim 1, wherein at least a first dielectric film, a phase change film, and a second dielectric film are laminated on the transparent substrate. 5. The light according to claim 1, wherein at least a first dielectric film, a phase change film, a second dielectric film, and a metal film are laminated on the transparent substrate. recoding media. 6. Tracks for recording information are alternately provided on the surface of the transparent substrate with different heights, and odd tracks of high-place tracks [or low-place tracks] have the first track for each unit information section. An unevenness for address identification is formed in the block by changing the track width, and the second track for each unit information section is formed on the even track of the high-altitude track [or the low-altitude track].
By using an optical recording medium in which concavities and convexities for address identification are formed in the blocks of the above, the information is recorded on the odd-numbered tracks of the high-altitude track [or the low-altitude track] or the information is recorded. When playing,
When recognizing the address from the unevenness for identifying the address of the first block and recording or reproducing the information on the even-numbered track of the high-altitude track [or the low-altitude track],
When the address is recognized from the unevenness for identifying the address of the second block, and the information of the low-place track [or the high-place track] is recorded or the information is reproduced, the first block The recording / reproducing method of the optical recording medium, wherein the address is controlled so as to be recognized from the address identification unevenness and the address identification unevenness of the second block.