JP2972900B2 - Optical information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium for recording and reproducing information using a laser beam.

[0002]

2. Description of the Related Art CAV is used as a recording / reproducing method for an optical information recording medium such as an optical disk.
System, CLV system, and MCAV system. Of these, CA
The V system is a system in which recording and reproduction are performed with the rotation speed and recording data rate of the disc being constant at the inner and outer circumferences. This method has a disadvantage that the recording density per track becomes smaller toward the outer periphery. In the CLV method, the number of revolutions is controlled according to the track radius of the disk so that the linear velocity is constant, recording and reproduction are performed at a constant data rate, and the recording capacity is increased while the linear recording density on the inner and outer circumferences is constant. It is. This method has a drawback that the access time is long because the number of rotations is controlled. The MCAV system is a system in which the rotational speed is fixed to compensate for the drawbacks of both the CAV system and the CLV system, and the recording and reproduction are performed by switching the demodulation and modulation frequencies according to the access position. In this system, the disk from the inner circumference to the outer circumference is divided into a plurality of groups in the radial direction, the number of sectors is fixed in each group, and the number of sectors per track is one or more between groups. Has been increased or decreased. However, according to this method, crosstalk occurs in the frequency switching track, which may lead to erroneous recognition of information.

In order to solve the above-mentioned drawback, Japanese Patent Application Laid-Open No. 2-152
No. 031 has a spiral or concentric track, and this track is divided into a plurality of groups in the radial direction, and each of the groups sequentially has the number of sectors per track according to the position in the radial direction. There has been proposed an optical information recording medium in which one or more non-recordable special tracks are provided at the boundary positions between the groups, which are increased or decreased.

[0004] However, according to the technique proposed in the above publication, the use-inhibited track information at the switching boundary may appear as crosstalk when the used track is reproduced, and the address index may be erroneously read. There is a possibility that the jitter of the data part may be increased.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides an optical information recording medium having a minimum configuration, having no crosstalk at the boundary between groups, and having a short access time. The purpose is to do.

[0006]

In order to achieve the above object, an optical information recording medium according to the present invention is an optical information recording medium of the MCAV system having spiral or concentric tracks. It is characterized in that a track consisting of only one or a plurality of guide grooves exists at the boundary position between the divided groups.

Next, the materials constituting the optical information recording medium of the present invention and the necessary characteristics of each layer will be specifically described.

(1) Substrate A required characteristic of the substrate is that it must be transparent to the laser beam used only when recording / reproducing is performed from the substrate side, and need not be transparent when it is performed from the recording layer side. As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, glass, ceramic, metal or the like can be used.

Note that a guide groove or guide pit for tracking and a preformat such as an address signal may be formed on the surface of the substrate.

(2) Undercoating layer The undercoating layer is (a) improvement in adhesiveness, (b) barrier against water or gas, (c) improvement in storage stability of the recording layer, and (d) improvement in reflectance. , (E) protection of the substrate from a solvent, (f) formation of a pre-groove, and the like. For the purpose of (a), polymer materials, for example, various polymer substances such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents. For the purposes of (b) and (c), inorganic compounds other than the above-mentioned polymer materials, for example, Si
Metals or metalloids, such as O ₂ , MgF ₂ , SiO, TiO ₂ , ZnO, TiN, SiN, for example, Zn, Cu, S, Ni, Cr, Ge, Se, Au, A
g, Al or the like can be used. Further, for the purpose of (d), a metal, for example, Al, Ag or the like, or an organic thin film having a metallic luster, for example, a methine dye, a xanthene-based dye, or the like can be used, and (e) and (f) For the purpose (1), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.

(3) Protective layer The protective layer (a) protects the recording layer from scratches, dust, dirt, etc., (b) improves the storage stability of the recording layer, and (c) improves the reflectance. Used for purpose. For these purposes, the materials shown in the undercoat layer can be used.
Inorganic materials such as SiO and SiO ₂ can also be used. As organic materials, polymeryl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon Resin, natural rubber, styrene-butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil, rosin, and other heat-softening and heat-melting resins can also be used.

(4) Recording Layer The recording layer causes some optical change by irradiation of laser light and records information by the change. Organic materials include polymethine dyes, naphthalocyanine, phthalocyanine, and the like. Squarylium-based, croconium-based, pyrylium-based, naphthoquinone-based, anthraquinone-based, xanthene-based, triphenylmethane-based, metal complex compounds, and the like.The above dyes may be used alone or in combination of two or more. Is also good. Further, as inorganic materials, Te, Ge, Se, In, Sb, Sn, Zn, Au, A
Metals such as l, Cu, Pt, and metalloids may be used alone,
An alloy or a laminate of two or more kinds may be used. The optical change may be any of a phase change, a bubble, and a drilling type. Furthermore, a magneto-optical recording layer mainly composed of FeTbCo may be used, or a spiropyran or fluoxide-based photochromic material may be used.

The thickness of the recording layer is suitably from 100 to 10 μm, preferably from 200 to 2 μm. As the film forming method, CVD, sputtering, or solvent coating (eg, dip coating, curtain coating, spray coating, spinner coating, blade coating, roller coating, etc.) can be used.

(5) Reflective layer The reflective layer desirably has high reflectivity and is hardly corroded.
A metal having luster is exemplified, and preferably, Al, Au and the like are exemplified. The thickness is suitably 100 to 50 μm, preferably 200 to 20 μm. Examples of the film forming method include vapor deposition and sputtering.

In addition, the undercoat layer, the recording layer, the protective layer,
The reflective layer may contain stabilizers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, and the like.
The medium of the present invention is a read-only medium, a write-once medium,
Any rewritable medium including magneto-optics may be used.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an improvement of an optical information recording medium of the MCAV system, and several embodiments will be described in detail with reference to the drawings.

First, the technology on which the present invention is based will be described with reference to FIGS. 4 and 5. In FIG. 1, reference numeral 1 denotes an MCAV optical information recording medium in which a metal film is formed on the surface of a disk-shaped substrate made of, for example, glass or plastic. A groove-shaped track 2 is previously formed in a spiral or concentric shape on the surface thereof. Track 2 is divided into a plurality of sectors 3 and each sector 3
Consists of an index information area 4 and a data section 5.
The medium 1 is radially divided into a plurality of groups 6-1, 6-2, 6-3,... From the outer periphery to the inner periphery. Up to this point, the description of the medium of the MCAV system is very general. However, in the above-mentioned publication (Japanese Unexamined Patent Application Publication No. 2-152030), as shown in FIG.・
..Two prohibited special tracks 8-1 at the boundary position
8-2 is provided to prevent erroneous recognition of index information of an adjacent track by crosstalk.

However, according to the technique disclosed in the above publication, when the boundary portion between the groups 6-1, 6-2, 6-3,... In addition to affecting playback information, not only can index (address) information not be reliably played,
Crosstalk also exists in the data part, which causes an increase in data part jitter.

The present invention solves such a problem as follows. FIG. 1 shows an example of an optical information recording medium (groove recording method) according to the present invention, in which two tracks 9 consisting of only grooves are provided at the boundary positions between groups. That is, two grooves are provided between the usable tracks 7 of a certain group and the usable tracks 7 'of an adjacent group. Even if the outermost periphery of the usable track 7 or the innermost periphery of the usable track 7 'thus formatted is reproduced, no different crosstalk component exists in the index information area 4 and the data portion 5 Does not have any crosstalk component. The number of grooves (grooves only) provided at the boundary position may be one or more,
Preferably, it is one or two.

FIG. 2 shows a part of a medium in which land recording is performed by changing the medium system of FIG. 1 to a groove system.

Further, according to the present invention, a configuration as shown in FIG. 3 can be adopted. FIG. 3 shows a land recording type medium.
A mirror portion 9 'corresponding to three track pitches is provided between a usable track 7 of a certain group and a usable track 7' of an adjacent group. The width of the mirror surface portion 9 'may be at least 0.01 track pitch in order to achieve the object of the present invention.
~ 2 bottles. Further, on the outermost periphery of the usable track 7 of a certain group, there is provided an information section 10 indicating that the section is a mirror section. This information section 10 may be provided on the innermost circumference of the usable track 7 'of the adjacent group.

Even in the configuration shown in FIG. 3, there is no crosstalk in the data portion of the boundary track as in the case of FIG. 1, so that it is very advantageous for data reproduction. Further, when the information section 10 is provided, it is necessary to take care that the crosstalk component of the information section 10 is applied to the index information area 4 when reproducing a track inside the one track so that an address reading error does not occur. .

The access time of the track 9 or the mirror surface 9 'provided at the boundary can be shortened if the laser beam is scanned while the drive is in a focus-in state and a tracking-off state while waiting for access.

Next, a specific production example will be described. Figure 1,
Formats shown in 2, 3, and 4, track pitch
A cyanine dye represented by the following formula 1 was added to an 8 μm polycarbonate injection molded plate by methanol: methyl ethyl ketone = 9: 1.
Dissolved in a solvent mixture of
The film was formed such that Using a pair of such substrates with a recording film, an optical disk having an air sandwich structure was manufactured.

Embedded image

Each of the optical disks manufactured as described above is mounted on a turntable of an optical disk drive and tilted for 15 minutes, and the outermost track of the usable track 7 in each figure (the track where the information section 10 is present in FIG. 3). Was reproduced 10,000 times, there were no reading errors in the optical disks of the formats of FIGS. 1 and 2, and there were 5 reading errors in the optical disk of the format of FIG. 3 and 7 times in the optical disk of the format of FIG.

Also, when data was written to the 7 track portions of each of the optical disks produced above and the jitter at that time was measured, the optical disk of the format of FIG. 4 showed a 25% jitter compared to the optical disks of FIGS. Increased.

[0027]

As described above in detail, according to the present invention, since the above-mentioned configuration is employed, the crosstalk component is small (at all), the information index is hardly erroneously read, and the jitter due to the crosstalk in the data portion is increased. Is prevented, and an optical information recording medium capable of high-speed access can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an optical information recording medium according to the present invention.

FIG. 2 is a diagram showing another example of the optical information recording medium according to the present invention.

FIG. 3 is a diagram showing still another example of the optical information recording medium according to the present invention.

FIG. 4 is a diagram showing an example of a conventional optical information recording medium.

FIG. 5 is an enlarged view showing a part of the optical information recording medium of FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical information recording medium 2 track 2 sector 4 Index information area 5 Data part 6 Group 7, 7 'Usable track 9 Track at boundary position 9' Mirror part at boundary position 10 Information part indicating that it is a mirror part afterwards

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) G11B 7/007 G11B 7/00 G11B 7/24 G11B 20/12

Claims (5)

(57) [Claims] 1. In an MCAV optical information recording medium having spiral or concentric tracks, one or a plurality of guide grooves are provided at a boundary position between each of a plurality of radially divided tracks. An optical information recording medium, characterized in that a track consisting of only one exists. 2. The method according to claim 1, wherein a mirror portion having no preformat pre-groove is present at the boundary position at a width of 0.01 times or more of a track pitch, instead of a track having only one or a plurality of guide grooves. Claim 1
An optical information recording medium according to claim 1. 3. At least one of a starting point and an ending point of a track or a mirror part existing at the boundary position is provided with information for recognizing that the track or the mirror part is before or after the point. Claim 1.
Or the optical information recording medium according to 2. 4. A track or a mirror portion existing at the boundary position rotates the optical information recording medium, keeps reproduction light on, and causes a pickup to wait on the track or the mirror portion while waiting for access. The optical information recording medium according to claim 1 or 2, wherein 5. A track or mirror portion existing at the boundary position is a use prohibited area, and at least one of a start point and an end point of the track or mirror is provided with information for recognizing that the use area is before and after the use prohibited area. 3. The optical information recording medium according to claim 1, wherein: