JP2002123981A - Optical information recording medium, optical information recording and reproducing method and optical information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a medium itself from being damaged or the recording or reproducing in/from the medium from being disabled even when a condenser lens touches the medium during the focus pull-in operation. SOLUTION: In the optical information recording medium 10, a recording layer 2 to record information, a cover layer 3 to protect the surface of the recording layer 2 and a hard coating layer 4 covering the surface of the focus pull-in exclusive region 101 are successively formed on a substrate 1. The medium has the focus pull-in exclusive region 101 by forming the thick hard coating layer 4 having high hardness on the outermost surface of the medium 10 opposing an optical head 5. This exclusive region is used only for the focus pull-in operation so that even when the optical head 5 touches the medium 10 by some external force, the information recorded in the medium 10 is not influenced. Because the hard coating layer 4 with high hardness is formed thick in the exclusive region, the region has an extremely firm structure against contact by the condenser lens.

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 capable of recording information at a high density by using a laser beam or reproducing information recorded at a high density by using a laser beam. The present invention relates to an information recording / reproducing method for the optical information recording medium and an optical information recording / reproducing apparatus for recording / reproducing on / from the optical information recording medium, and more particularly, to a focus pull-in for focusing a laser beam on an information recording surface of the medium. The present invention relates to an optical information recording medium provided with a dedicated area, an optical information recording / reproducing method using the same, and an optical information recording / reproducing apparatus.

[0002]

2. Description of the Related Art An optical disk recording system using a laser beam is capable of performing large-capacity recording and non-contact high-speed access. Optical disks are classified into a read-only type known as a compact disk and a laser disk, a write-once type that can be recorded by the user himself, and a rewritable type that can be repeatedly recorded and erased by the user. A write-once / rewritable optical disk is used as an external memory of a computer or as a document / image file.

In the read-only type, data files typified by CD-ROMs have rapidly spread, and are used as high-density recording media in the personal field. Also,
Paying attention to the large capacity of this CD-ROM, MPEG-2
The application as a multimedia file including image data using image compression techniques such as the above is being studied. For this purpose, the current capacity of 650 MB / disk is not enough, and DVD-ROMs with a capacity of 4.7 GB have begun to be used. On the other hand, DVD players that provide small, high-quality video have been commercialized for read-only consumer image files such as laser disks, but further densification for high-definition playback remains an important theme. I have.

[0004] In the write-once optical disc, a certain market is secured in an application field in which the merit that recorded information can be stored stably is used to the utmost. And in this application, in the sense of taking advantage of economies of scale,
Large capacity and high density are important issues to consider. Recently, CD-Rs as write-once CDs are rapidly spreading. As rewritable optical disks, there are a phase-change optical disk using a phase change of a recording film and a magneto-optical disk using a change in the magnetization direction of a perpendicular magnetization film. Of these, phase-change optical disks do not require an external magnetic field and can be easily overwritten.
It is expected to become the mainstream of rewritable optical disks.
For a magneto-optical disk, 3.5 GB size is 1.3 GB
Capacity products began to appear.

On the other hand, in a phase change type optical disk, a CD-R
CD-RWs compatible with OM have begun to spread widely, and 4.7 GB capacity DVD-RAM and DVD-
Large-capacity products, such as RW, have begun to be sold. Here, too, large capacity and high density are important keywords. In the reproduction-only type, an Al alloy-based metal reflection film is formed on uneven pits previously formed by injection molding on a substrate and used for reproduction. In write-once type, Te or B
A medium is used in which an alloy material of a low melting point metal such as i, Se, Sn or the like or a dye material having absorption characteristics at a laser wavelength to be used is thinly applied on a substrate.

In the rewritable type, in a magneto-optical disk, a medium in which an alloy thin film of a rare earth metal such as Tb, Gd, Dy, and Ho and a main transition metal such as Fe, Co, and Ni is sandwiched between transparent protective films such as SiN. In the phase-change optical disk, a chalcogenide-based thin film such as GeSbTe or InSbTe is used as a recording film. The recording film of a phase change optical disc, Additional, AgInSbTe based, Sb ₇ Te ₃ + Ge system, InSe system, InTe
System, AsTeGe system, TeOx-GeSn system, TeSeSn system, SbSeBi system, BiS
eGe type or the like is used. The thin film described here is formed by a film forming method such as a resistance heating vacuum evaporation method, an electron beam vacuum evaporation method, or a sputtering method, or a spin coating method.

In a commonly used optical disk, 1.2
Information is formed on a polycarbonate substrate having a thickness of 0.6 mm or 0.6 mm in the form of a pit or a change in the state of a recording film caused by condensed laser light, and the laser light is condensed from the polycarbonate substrate side to reproduce recorded information. Is performed. However, when the numerical aperture (Numerical Aperture) (hereinafter, referred to as NA) of the condenser lens is increased in order to perform higher-density recording, fluctuations in the focused spot diameter shape due to the inclination of the disk itself are caused by the thick substrate. There was a problem of becoming larger. On the other hand, a thin cover layer of about 100 μm thickness is formed on the disk surface,
A method of recording / reproducing / erasing information via a cover layer has been proposed (for example, K. Osato et al., Proceedings of
SPIE, Vol.3041, Optical Data Storage, pp.80-86,19
98). Here, NA larger than that of a normal condenser lens
(For example, a lens of NA 0.85) is used.

[0008]

When such a high NA lens is used, the distance between the optical disk and the condenser lens is inevitably reduced. When the conventional NA is around 0.6,
Although the distance between the optical disk and the condenser lens can be ensured to be 1 mm or more, when the NA is 0.85, the distance between the optical disk and the condenser lens is extremely reduced to about 100 μm. In this case, there is a high possibility that the disk and the optical head condenser lens come into contact due to some disturbance. Normally, in an optical disk device, before the optical disk is mounted, the condenser lens of the optical head is retracted to a standby position. When the disk is mounted and recording / reproducing operation starts, an optical spot is first placed on the medium surface. Is performed, that is, a so-called “pull-in” operation of a focus servo is performed. At this time, the condenser lens moves from the standby position to the focus servo pull-in position and starts “pull-in”. However, this involves the movement of the lens, and the fluctuation of the focus pull-in surface of the optical disc itself at this time is large. Is assumed, the operation has a high probability that the condenser lens and the medium are in contact with each other. That is, the conventional low N
Compared with the medium using the condenser lens of A, in the high NA system, the disc and the optical head condenser lens come into contact,
There is a disadvantage that the disc is likely to be damaged.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a medium itself caused by contact between a condensing lens and a medium during a focus pull-in operation in a high NA system. To provide an optical information recording medium capable of stably and reliably performing the recording / reproducing operation of the recorded information by preventing in advance the damage of the recorded information or the inability to record / reproduce the recorded information due to the damage, and adapted the medium accordingly. An object of the present invention is to provide an optical information recording / reproducing method and an optical information recording / reproducing apparatus.

[0010]

According to the present invention, in order to achieve the above object, information which can be read optically is recorded, or information is optically recorded and this is optically recorded. In a readable optical information recording medium, a focus pull-in dedicated area is provided for performing an operation of condensing a light beam having a small aperture with a higher mechanical strength than other areas on an information recording surface. An optical information recording medium is provided.

According to the present invention, in order to achieve the above object, optically readable information is recorded, or information can be optically recorded and read out optically. An optical information recording medium, wherein a donut-shaped focus pull-in-only area for performing an operation of condensing a light beam having a small diameter on the information recording surface is provided,
Is provided.

Preferably, the information recording surface is covered with a cover layer, and a hard coat layer having a higher hardness than the cover layer is formed on the cover layer in the focus pull-in exclusive area. Or the information recording surface is covered with a cover layer and a hard coat layer having a higher hardness than the cover layer, and the thickness of the hard coat layer in the focus pull-in exclusive region is different from that of the hard coat layer. Or the information recording surface is covered with a cover layer and a hard coat layer having a higher hardness than the cover layer, and the total film thickness of the cover layer and the hard coat layer Is constant, and the thickness of the hard coat layer in the focus pull-in exclusive region is made larger than the thickness of the other region of the hard coat layer. Preferably, the focus pull-in exclusive area is provided in a donut shape inside the innermost circumference of the information recording area or between the information recording areas.

According to the present invention, in order to achieve the above object, prior to an operation of reading or erasing information recorded on an optical information recording medium, or an operation of recording information on an optical information recording medium, Prior to the method, there is provided an optical information recording / reproducing method, wherein a focus pull-in operation of focusing a light beam on an information recording surface of the specific area on the optical information recording medium using the specific area is performed. You. Preferably, the linear velocity of the optical information recording medium at the time of reading or erasing information recorded on the optical information recording medium or at the time of recording information on the optical information recording medium is V, at the time of focus pull-in operation. Assuming that the linear velocity of the optical information recording medium is v, one of the following conditions is satisfied: V = v> 0 V>v> 0 V> v = 0.

According to the present invention, there is provided a drive mechanism for driving an optical information recording medium, an optical head for irradiating the optical information recording medium with a light beam, and
The optical head is provided with an actuator for moving a position of a lens provided in the optical head so that a light beam emitted from the optical head is focused on an information recording surface of the optical information recording medium. An optical information recording / reproducing apparatus, wherein the optical information recording / reproducing apparatus reproduces information,
Prior to performing an erasing or recording operation, a mechanism for guiding the optical head onto a focus pull-in dedicated area set on the optical information recording medium is provided, and the actuator is driven on the focus pull-in dedicated area. An optical information recording / reproducing apparatus, wherein a focus pull-in operation is performed so that a light beam emitted by the optical head is focused on an information recording surface on the optical information recording medium.

[0015]

Next, an embodiment of the present invention will be described with reference to the drawings. FIGS. 1A to 1C are cross-sectional views showing an embodiment of the optical information recording medium of the present invention in which the form of forming the hard coat layer is changed. As shown in FIGS. 1A to 1C, the optical information recording medium 10 of the present invention includes at least a substrate 1 made of polycarbonate or the like.
A recording layer 2 for recording information; a cover layer 3 for protecting the surface of the recording layer 2;
01 has a hard coat layer 4 covering the surface. That is, the optical information recording medium 10 of the present invention has the hard coat layer 4 formed of a high-hardness material on the outermost surface facing the optical head 5 of the optical information recording medium 10 in the focus pull-in exclusive area 101. It is characterized by the following.
The focus pull-in exclusive area 101 is an area used only at the time of “focus pull-in” which is one of operations when irradiating the optical information recording medium 10 with the converged spot of the optical head 5. Of the medium 1 even if the condenser lens of
It does not affect the information itself recorded in 0 (that is, the information itself stored in the information recording area). Further, since the hard coat layer 4 is formed thickly with a material having high hardness in this dedicated area, it has extremely high damage resistance against contact with the condenser lens.

In recording / reproducing high-density information, a condensing lens having a large numerical aperture NA is usually used. For example, in a condenser lens having an NA of 0.85, the distance from the front end of the lens to the surface of the medium is extremely narrow, about 100 μm. Therefore, the condenser lens and the medium easily come into contact with each other due to disturbance at the time of focus pull-in. The present invention provides a focus pull-in dedicated area having high damage resistance, thereby preventing damage to the medium itself caused by contact between the condensing lens and the medium during the pull-in operation, or the inability to record and reproduce recorded information due to the damage. This enables stable and reliable information recording / reproducing operations to be performed.

Next, the formation of the hard coat layer 4 will be described. The hard coat layer 4 is formed only on the pull-in only area 101 of the medium 10 as shown in FIG. Alternatively, as shown in FIG. 1B, the hard coat layer 4 may be formed on the entire surface of the medium 10 and only the focus pull-in exclusive region 101 may be formed thick, or as shown in FIG. Then, the cover layer 3 and the hard coat layer 4 are formed so that the thickness from the outermost surface of the medium to the information recording layer 2 is constant, and the cover layer 3 is formed thin on the focus pull-in exclusive area 101. In that region, the hard coat layer 4 may be formed so as to be thicker than other regions.

Optical information recording medium 10 used in the present invention
May be any of a read-only type, a write-once type, and a rewritable type. FIG. 2 to FIG. 5 are cross-sectional views showing embodiments of the optical information recording medium of the present invention in which information recording methods are different.
FIGS. 2 to 5 show only those having the hard coat layer 4 shown in FIG. 1A, but the hard coat layers shown in FIGS. 1B and 1C can be similarly employed. FIG.
Is a cross-sectional view of a read-only medium, and shows information pits 22;
Is adopted in which a reflective film 21, an adhesive layer 31, a cover layer 3, and a hard coat layer 4 are sequentially formed on a substrate 1 having. In the case of the write-once type, as shown in FIG. 3, a write-once type recording film 23, an adhesive layer 31, a cover layer 3, and a hard disk are formed on a substrate 1 having a guide groove (not shown) for tracking a condensed spot. The configuration in which the coat layer 4 is sequentially formed is adopted,
For the write-once recording film 23, an organic dye represented by phthalocyanine, or a low melting point metal alloy thin film represented by TeSn is used. When an organic dye is used, a configuration in which a reflective film is provided below the write-once recording layer 23 is employed.

When a magneto-optical recording method is adopted as a rewritable type, as shown in FIG. 4, a reflective film 21 is formed on a substrate 1 having a guide groove (not shown) for tracking a condensed spot. , Lower protective film 24, magneto-optical recording film 25, upper protective film 26, adhesive layer 31, cover layer 3, hard coat layer 4
Are sequentially formed. As the magneto-optical recording film 25, a rare earth and a main transition metal alloy thin film is used.
Are typical. In some cases, a multilayer recording film is also used. A multilayer structure having a magnetic super-resolution effect can also be applied. Protective films 2 above and below the recording layer
As the layers 4 and 26, nitride dielectric layers such as SiN and AlN are used.

When a phase change recording method is adopted as a rewritable type, as shown in FIG. 5, a reflective film 21 is formed on a substrate 1 having a guide groove (not shown) for tracking a condensed spot. , Lower protective film 24, phase change recording film 27, upper protective film 26, adhesive layer 31, cover layer 3, hard coat layer 4
Are sequentially formed. As the phase change recording film 27, a chalcogenide alloy thin film is used, and a phase change recording film represented by GeSbTe or AgInSbTe is generally used. As protective films 24 and 26 above and below the recording film, SiO ₂ ,
A dielectric layer of ZnS, AlN, GeN, or the like is used, and the dielectric layer can be used in a multilayered configuration.

Next, the optical information recording / reproducing method of the present invention will be described. FIG. 6 is a cross-sectional view showing a driving state of a medium for explaining the optical information recording / reproducing method of the present invention.
The optical information recording medium 10 is attached to a shaft of a motor 6 and is rotated at a desired rotation speed. On the optical information recording medium 10, an optical head 5 that emits laser light and receives reflected light thereof is installed so as to be movable in a direction orthogonal to the rotation axis of a motor 6. The optical head 5 is provided with a condenser lens 52 for focusing a laser beam on the information recording layer of the optical information recording medium 10. Optical information recording medium 10
Is rotated at a constant number of revolutions, a pull-in operation is performed in the pull-in-only area 101 of the medium 10 to focus the condensed spot on the recording layer of the medium 10.

Next, after the focus is pulled in, the optical head 5 is moved to a desired position in the information recording area 102, and a tracking operation for pulling in to a desired track is performed. As a result, a desired track or a desired sector can be accessed, and information can be recorded or reproduced therefrom. Here, the pull-in only area 101
May be provided on the inner peripheral portion of the disk or may be provided on the outer peripheral portion of the disk. Alternatively, a pull-in only area 101 may be provided between the information recording areas.

Next, an optical information recording / reproducing apparatus according to the present invention will be described. FIG. 7 is a schematic configuration diagram of an optical information recording / reproducing apparatus according to the present invention. Here, a case where a disc-shaped optical information recording medium is used will be described. That is, a disc-shaped optical information recording medium 10 having an area dedicated to focus pull-in is mounted on the recording / reproducing apparatus so as to face the optical head 5.

The optical head 5 includes a laser 51 for emitting laser light, a condenser lens 52 for condensing the laser light on the information recording layer of the medium 10, and a beam splitter for guiding reflected light from the medium 10 to a detection circuit. 57, 58 and a signal detection circuit 5 for detecting a signal guided from the beam splitter 57.
5, a beam splitter 59 that divides the signal of the beam splitter 58 into two, a tracking error detection circuit 54 that detects a tracking error from a signal from the beam splitter 59, and a focus error detection circuit 53 that also detects a focus error. , Condenser lens 5
And an actuator 56 for driving the actuator 2.

The laser 51 is connected to the laser driver 7, whereby the apparatus controls the laser to output a desired optical output when recording, erasing, or reproducing. Then, the error detection circuits 53, 5
The focus and tracking error signals obtained in 4 are processed by the servo circuit 8 connected to the optical head 5, and a drive signal is supplied to the actuator 56. The condenser lens 52 itself of the optical head 5 is mounted on an actuator 56 that can move the condenser lens 52 in the focus direction and in the direction across the tracking guide groove.
The optical head 5 itself is mounted on a screw screw feed system or a feed system 9 of a linear slider so that the optical head 5 can move from the inner circumference to the outer circumference of the disk.

The operation at the time of recording / reproducing / erasing is as follows. The optical head 5 is once sent to the focus pull-in exclusive area of the medium 10 by the feed system 9, and the reflected light obtained from the exclusive area is collected by the condenser lens 52. , Beam splitters 58 and 59
Through the focus error detection circuit 53.
As a focus error detection method, an astigmatism method, a knife edge method, a critical angle method, and the like are known, and any method can be adopted. An error signal detected by any of the methods is sent to the servo circuit 8, which drives the actuator 56 to perform focus pull-in.

After the completion of the focus pull-in, the optical head 5
Is moved to a desired position in the information recording area of the medium 10 by the feed system 9, and normal operations such as recording, reproduction or erasing of information including tracking are performed. According to the information recording, reproducing or erasing method of the present invention, even if the condenser lens 52 and the medium 10 come into contact during the above-described focus pull-in operation, the information recording area of the disc may have some influence. Can be avoided.

[0028]

Next, embodiments of the optical information recording medium of the present invention will be described in detail. [Example 1] An outer diameter of 120 mm, an inner diameter of 15 mm, in which information pits were previously transferred and formed by an optical disk stamper,
A polycarbonate resin plate having a thickness of 1.1 mm is used as a support substrate, and an Al alloy reflective film is formed on this information pit surface by 100 nm.
Was formed by a sputtering method with a thickness of Next, as a cover layer, a polycarbonate cover film having a thickness of 70 μm was coated with an ultraviolet curable resin (SD manufactured by Dainippon Ink and Chemicals, Inc.).
-523). At this time, the total thickness of the cover film and the ultraviolet curable resin was 101 μm. The information pits previously formed on the substrate are spirally formed on the substrate, and the track pitch, which is the interval between the pit rows, is 0.30 μm, and the minimum pit length is 0.185.
μm.

The inner peripheral portion of the disk on which the cover film is formed, a region having a radius of 20 μm to 25 μm, a thickness of 2 μm
Thus, a hard coat resin film having a hardness higher than that of the polycarbonate after curing was formed. A hard coat resin was applied from the inner periphery in a state where a doughnut-shaped protective film was pasted on the outer periphery from a radius of 25 μm in advance, and the protective film was removed after curing with ultraviolet rays. Dicure (trade name: SD-715, manufactured by Dai Nippon Ink Co., Ltd.) was used as the hard coat resin. Continue with NA 0.85
An attempt was made to reproduce a disc created using an optical head (wavelength 405 nm) equipped with a condenser lens of No. The disk is rotated at a linear velocity of 1.7 m / s and the reproducing power is 0.35 mW
Once the focus pull-in operation was performed at a radius of 22 mm on the inner circumference, the focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm in a state where the focus was pulled, and the reflected light from the information pit was reproduced. As a result, a good eye pattern signal was reproduced.

[Embodiment 2] Using an optical disk stamper,
Outer diameter 1 with guide groove for tracking transferred and formed in advance
20 mm, an inner diameter of 15 mm, and the supporting substrate polycarbonate resin plate having a thickness of 1.1 mm, onto a substrate, Al alloy reflective film, ZnS-SiO ₂ protective underlayer, GeSbTe recording film, a ZnS-SiO ₂ upper protecting layer successively A phase change recording medium formed by sputtering was formed. Next, as a cover layer, a thickness of 70 μ
m of the polycarbonate cover film was bonded with the above-mentioned ultraviolet curable resin. At this time, the total thickness of the cover film and the ultraviolet curable resin was 101 μm. The track guide groove formed in advance on the substrate is
It is formed in a spiral shape on the substrate, and has a land width of 0.
3 μm, groove width 0.3 μm, depth 45 nm.

The formation of the hard coat resin film is performed in the same manner as in the first embodiment.
The same was done. Subsequently, the entire surface of the disk is initialized by a high-power laser to crystallize the recording film, and then recorded on the prepared disk using an optical head (wavelength: 405 nm) equipped with a converging lens of NA 0.85. Tried to regenerate. When the disk was rotated at a linear velocity of 3.5 m / s, the reproducing power was set to 0.40 mW, and the pull-in operation of the focus was once performed at a position of an inner radius of 22 mm, the focus was successfully drawn. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a signal train including a pulse having a shortest mark length of 0.185 μm was recorded on the medium. Recording power is 4.2m
W. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 3] The supporting substrate forming method is the same as that of Embodiment 2.
On this substrate, a magneto-optical recording medium was formed in which an Al alloy reflective film, a SiN underlayer protective film, a TbFeCo recording film, and a SiN upper protective film were sequentially formed by sputtering. Next, as a cover layer, a polycarbonate cover film having a thickness of 70 μm was bonded with the above-described ultraviolet curable resin. At this time, the total thickness of the cover film and the ultraviolet curable resin was 101 μm. Note that the track guide grooves formed in advance on the substrate are the same as those in the second embodiment.

The formation of the hard coat resin film was performed in the same manner as in Example 1. After that, the whole disk is 20kOe
(1.6MAT / m)
An optical head (wavelength 4
05 nm), recording and reproduction on the created disc was attempted. The disk was rotated at a linear velocity of 3.5 m / s, the reproducing power was set to 0.35 mW, and the inner radius was once 22 mm.
When the focus pull-in operation was performed at the position
The focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a signal train including a pulse having a shortest mark length of 0.185 μm was recorded on the medium. The recording power was 3.9 mW. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 4] The method for forming a supporting substrate is described in Embodiment 2.
A TeSn-based alloy thin film was formed on this substrate by sputtering to obtain a write-once recording film. Next, as a cover layer, a polycarbonate cover film having a thickness of 70 μm was bonded with the above-described ultraviolet curable resin.
At this time, the total thickness of the cover film and the ultraviolet curable resin was 101 μm. Note that the track guide grooves formed in advance on the substrate are the same as those in the second embodiment.

The formation of the hard coat resin film was performed in the same manner as in Example 1. Subsequently, the entire surface of the disk is initialized by a high-power laser to crystallize the recording film, and then the optical disk (wavelength: 405 nm) equipped with a converging lens with an NA of 0.85 is used to write the disk. Attempted recording and playback. The disk is rotated at a linear velocity of 3.5 m / s,
The reproducing power is set to 0.32 mW, and the radius of the inner circumference is once set to 22.
When the focus pull-in operation was performed at the position of mm, the focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a recording signal having a shortest mark length of 0.185 μm was recorded on the medium. The recording power was 3.5 mW. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 5] The supporting substrate forming method is the same as that of Embodiment 1.
An Al alloy reflective film was formed on the information pit surface by sputtering at a thickness of 100 nm. Next, as a cover layer, a polycarbonate cover film having a thickness of 70 μm was bonded with the above-described ultraviolet curable resin. At this time, the total thickness of the cover film and the ultraviolet curable resin was 99 μm. The arrangement of the information pits formed on the substrate is the same as that of the first embodiment.

Next, the entire surface of the cover film (radius 20 mm)
A resin for hard coating was formed to a thickness of 1.5 μm on the entire surface (from the outside to the outside) by a spin coating method, and was cured by irradiation with ultraviolet rays. Further, a hard coat resin was additionally formed on the inner peripheral portion of the disk on which the cover film was formed, in a region having a radius of 20 mm to 25 mm, so that the total thickness became 3.0 μm. At this time, a hard coat resin was applied from the inner periphery in a state where a doughnut-shaped protective film was stuck on the outer periphery from a radius of 25 mm in advance, and the protective film was removed after curing with ultraviolet rays.

Subsequently, an attempt was made to reproduce the created disk by using an optical head (wavelength: 405 nm) equipped with a condenser lens having an NA of 0.85. 1.7m / s linear velocity
, The reproducing power was set to 0.35 mW, and once the focus pull-in operation was performed at a position with an inner radius of 22 mm, the focus was successfully pulled in. After this, a radius of 45 m with the focus retracted
m, and when the reflected light from the information pit was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 6] The supporting substrate forming method is Embodiment 2.
It was carried out in the same manner as, Al alloy reflective film on the substrate, ZnS-SiO ₂ protective underlayer, GeSbTe recording film, thereby forming a phase-change recording medium which was formed by sequentially sputtering the ZnS-SiO ₂ upper protecting film. Next, as a cover layer, a polycarbonate cover film having a thickness of 70 μm was bonded with the above-described ultraviolet curable resin. At this time, the total thickness of the cover film and the ultraviolet curable resin was 101 μm. Note that the track guide grooves formed in advance on the substrate are the same as those in the second embodiment.

The formation of the hard coat resin film was performed in the same manner as in Example 5. Subsequently, the entire surface of the disk is initialized by a high-power laser to crystallize the recording film, and then the optical disk (wavelength: 405 nm) equipped with a converging lens with an NA of 0.85 is used to write the disk. Attempted recording and playback. The disk is rotated at a linear velocity of 3.5 m / s,
The reproduction power is set to 0.40 mW, and the inner radius 22
When the focus pull-in operation was performed at the position of mm, the focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a signal train including a pulse having a shortest mark length of 0.185 μm was recorded on the medium. Recording power is 4.2m
W. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 7] The method of forming a supporting substrate is described in Embodiment 2.
On this substrate, a magneto-optical recording medium was formed in which an Al alloy reflective film, a SiN underlayer protective film, a TbFeCo recording film, and a SiN upper protective film were sequentially formed by sputtering. Next, as a cover layer, a polycarbonate cover film having a thickness of 70 μm was bonded with the above-described ultraviolet curable resin. At this time, the total thickness of the cover film and the ultraviolet curable resin was 101 μm. Note that the track guide grooves formed in advance on the substrate are the same as those in the second embodiment.

The formation of the hard coat resin film was performed in the same manner as in Example 5 described above.
The same was done. Following this, the whole disk is 20kO
e (1.6 MAT / m 2) or more, and magnetized. Then, using an optical head (wavelength 405 nm) equipped with a converging lens of NA 0.85, recording on the created disc,
Tried to regenerate. The disk was rotated at a linear velocity of 3.5 m / s, the reproducing power was set to 0.35 mW, and the pull-in operation of the focus was performed once at a position of an inner radius of 22 mm. . Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a signal train including a pulse having a shortest mark length of 0.185 μm was recorded on the medium. Recording power is 3.9
mW. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 8] The method of forming a supporting substrate is described in Embodiment 2.
A TeSn-based alloy thin film was formed on this substrate by sputtering to obtain a write-once recording film. Next, a cover film made of polycarbonate having a thickness of 70 μm was bonded as the cover layer using the above-described ultraviolet curable resin. At this time, the total thickness of the cover film and the ultraviolet curable resin was 101 μm. Note that the track guide grooves formed in advance on the substrate are the same as those in the second embodiment.

The formation of the hard coat resin film was performed in the same manner as in Example 5. Subsequently, the entire surface of the disk is initialized by a high-power laser to crystallize the recording film, and then the optical disk (wavelength: 405 nm) equipped with a converging lens with an NA of 0.85 is used to write the disk. Attempted recording and playback. The disk is rotated at a linear velocity of 3.5 m / s,
The reproducing power is set to 0.32 mW, and the radius of the inner circumference is once set to 22.
When the focus pull-in operation was performed at the position of mm, the focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a recording signal having a shortest mark length of 0.185 μm was recorded on the medium. The recording power was 3.5 mW. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 9] The supporting substrate forming method is the same as that of Embodiment 1.
An Al alloy reflective film was formed on the information pit surface to a thickness of 100 nm by a sputtering method.
Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 20 mm to 25 mm,
(The one processed to have a thickness of 68 μm thinner by 2 μm than the other regions) was bonded by the above-mentioned ultraviolet curable resin. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 99 μm. The arrangement of the information pits formed in advance on the substrate is the same as that of the first embodiment. After the cover film is formed, a radius of 20 mm
A hard coat resin film having a high hardness after curing was formed so as to have a thickness of 4 μm from 25 mm to 25 mm and a thickness of 2 μm at the outer periphery from a radius of 25 mm, and was irradiated with ultraviolet rays to cure the resin.

Subsequently, an attempt was made to reproduce the created disk using an optical head (wavelength: 405 nm) equipped with a condenser lens having an NA of 0.85. 1.7m / s linear velocity
, The reproducing power was set to 0.35 mW, and once the focus pull-in operation was performed at a position with an inner radius of 22 mm, the focus was successfully pulled in. After this, a radius of 45 m with the focus retracted
m, and when the reflected light from the information pit was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 10] The supporting substrate was formed in the same manner as in Embodiment 2. An Al alloy reflective film, ZnS-Si
A phase-change recording medium in which an O ₂ underlayer protective film, a GeSbTe recording film, and a ZnS—SiO ₂ upper protective film were sequentially formed by sputtering was formed. Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 20 mm to 25 mm, which is processed to a thickness of 68 μm thinner by 2 μm than the other regions, is used) and is cured by the above-described ultraviolet curing. Bonded with resin. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 101 μm. The track guide groove formed in advance on the substrate is
This is the same as in the second embodiment.

The formation of the hard coat resin film is performed in the same manner as in the ninth embodiment. After that, the recording film is crystallized by performing an initializing operation using a high power laser over the entire surface of the disk.
An optical head (wavelength 4
05 nm), recording and reproduction on the created disc was attempted. The disk was rotated at a linear velocity of 3.5 m / s, the reproducing power was set to 0.40 mW, and the inner radius was once 22 mm.
When the focus pull-in operation was performed at the position
The focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a signal train including a pulse having a shortest mark length of 0.185 μm was recorded on the medium. The recording power was 4.2 mW. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

[Embodiment 11] The supporting substrate was formed in the same manner as in Embodiment 2. On this substrate, an Al alloy reflective film, a SiN underlayer protective film, a TbFeCo recording film, and a SiN upper protective film were sequentially formed by sputtering. A magneto-optical recording medium was formed. Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 20 mm to 25 mm, which is processed to a thickness of 68 μm thinner by 2 μm than the other regions, is used) and is cured by the above-described ultraviolet curing. Bonded with resin. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 101 μm. Note that the track guide grooves formed in advance on the substrate are the same as those in the second embodiment.

The hard coat resin film was formed in the same manner as in the ninth embodiment.
(1.6MAT / m)
An optical head (wavelength 4
05 nm), recording and reproduction on the created disc was attempted. The disk was rotated at a linear velocity of 3.5 m / s, the reproducing power was set to 0.35 mW, and the inner radius was once 22 mm.
When the focus pull-in operation was performed at the position of, the focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a signal train including a pulse having a shortest mark length of 0.185 μm was recorded on the medium. The recording power was 3.9 mW. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

Example 12 A supporting substrate was formed in the same manner as in Example 2, and a TeSn-based alloy thin film was formed on the substrate by sputtering to obtain a write-once recording film. Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 20 mm to 25 mm, which has been processed to a thickness of 68 μm thinner by 2 μm than other regions, is used) is coated with the above-described ultraviolet curable resin. Adhered. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 101 μm. Note that the track guide grooves formed in advance on the substrate are the same as those in the second embodiment.

The formation of the hard coat resin film is performed in the same manner as in the ninth embodiment. Subsequently, the entire surface of the disk is initialized by a high power laser to crystallize the recording film.
An optical head equipped with a 0.85 condenser lens (wavelength 405
nm), recording and reproduction on the created disc was attempted. The disk was rotated at a linear velocity of 3.5 m / s, the reproducing power was set to 0.32 mW, and once the focus pull-in operation was performed at the inner radius of 22 mm, the focus was successfully pulled in. Thereafter, the lens was moved to a radius of 45 mm with the focus pulled in, and a recording signal having a shortest mark length of 0.185 μm was recorded on the medium. The recording power was 3.5 mW. When the recorded track was reproduced, a good eye pattern signal could be reproduced.

Example 13 The supporting substrate was formed in the same manner as in Example 1, except that an Al alloy reflective film was formed on the information pit surface.
A film having a thickness of 00 nm was formed by a sputtering method. Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 20 mm to 22 mm, which is processed to a thickness of 68 μm thinner by 2 μm than other regions) is used as described above by ultraviolet curing. Bonded with resin. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 99 μm. In addition,
The arrangement of the information pits formed in advance on the substrate is described in Example 1.
Is the same as In addition, a radius of 22 mm to 24 mm
Area is a so-called lead-in area in which data relating to recording information is stored.

The formation of the hard coat resin film was performed in the same manner as in the ninth embodiment. Subsequently, the optical information recording / reproducing apparatus according to the present invention having an optical head (wavelength: 405 nm) equipped with a converging lens having an NA of 0.85 was used. I tried to play the created disc. When the disk was rotated at a linear velocity of 1.7 m / s, the reproducing power was set to 0.35 mW, and the pull-in operation of the focus was performed once at the inner radius of 21 mm, the focus was successfully pulled in. Thereafter, the disk was moved to a radius of 22 mm while the focus was pulled in, and the reflected light from the information pit from the lead-in area was reproduced. By forming the pull-in area in the area inside the lead-in as in the present embodiment, it is possible to smoothly shift to the recording and reproducing operations.

Example 14 A supporting substrate was formed in the same manner as in Example 1, and an Al alloy reflective film having a thickness of 100 nm was formed on the information pit surface by a sputtering method. Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 55 mm to 56 mm, which has been processed to a thickness of 68 μm thinner by 2 μm than the other regions, is used) and is cured by the above-described ultraviolet ray curing. Bonded with resin. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 99 μm.
The arrangement of the information pits formed in advance on the substrate is described in Example 1.
Is the same as After the cover film is formed,
A radius of 55 mm over the entire surface of the disc at an outer radius of 20 mm
To 56 mm, a hard coat resin film having a high hardness after curing was formed so as to have a thickness of 4 μm and a thickness of 2 μm in the other area, and the resin was cured by irradiation with ultraviolet rays.

Subsequently, an attempt was made to reproduce the disc produced using an optical information recording / reproducing apparatus according to the present invention having an optical head (wavelength: 405 nm) equipped with a converging lens having an NA of 0.85. The disc was rotated at a linear velocity of 1.7 m / s, the reproducing power was set to 0.35 mW, and the
When the focus pull-in operation was performed at a position of 5 mm, the focus was successfully pulled in. After that, the lens was moved to a radius of 56 mm with the focus pulled in, and the reflected light from the information pit was reproduced.
A good eye pattern signal could be reproduced. The outermost peripheral portion of the disk has a relatively large surface runout of the disk itself, and the probability of contact between the head and the medium at the time of focus pull-in becomes higher. By performing the focus pull-in operation slightly inside, stable recording and reproduction can be realized.

Example 15 A supporting substrate was formed in the same manner as in Example 1, and an Al alloy reflective film having a thickness of 100 nm was formed on the information pit surface by a sputtering method. Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 55 mm to 56 mm, which has been processed to a thickness of 68 μm thinner by 2 μm than the other regions, is used) and is cured by the above-described ultraviolet ray curing. Bonded with resin. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 99 μm.
The arrangement of the information pits formed in advance on the substrate is the same as that of the first embodiment.

The formation of the hard coat resin film was carried out in the same manner as in Example 14, and subsequently, an optical information recording / reproducing apparatus according to the present invention having an optical head (wavelength: 405 nm) equipped with a converging lens having an NA of 0.85 was used. Tried playing the created disc. The disk was rotated at a linear velocity of 0.5 m / s, the reproducing power was set to 0.35 mW,
When the focus pull-in operation was performed at a position of 5.5 mm, the focus could be pulled in more favorably than at a linear velocity of 1.7 m / s. Thereafter, the lens is moved to a radius of 56 mm with the focus being pulled, and the linear velocity is set to 1.7.
When the reflected light from the information pits was reproduced at a setting of m / s, a good eye pattern signal could be reproduced in a region up to a radius of 58 mm which is the outermost information pit formation portion. The outermost peripheral portion of the disk has relatively large surface runout of the disk itself, and the probability of contact between the head and the medium at the time of focus pull-in increases, but as in this embodiment of the present invention,
Once the focus pull-in operation is performed under a linear velocity condition lower than the used linear velocity, stable recording and reproduction can be realized.

Example 16 A supporting substrate was formed in the same manner as in Example 1, and an Al alloy reflective film having a thickness of 100 nm was formed on the information pit surface by a sputtering method. Next, as a cover layer, a polycarbonate cover film (here, a region having a radius of 55 mm to 56 mm, which has been processed to a thickness of 68 μm thinner by 2 μm than the other regions, is used) and is cured by the above-described ultraviolet ray curing. Bonded with resin. At this time, the total thickness of the 70 μm thick cover film and the ultraviolet curable resin was 99 μm.
The arrangement of the information pits formed in advance on the substrate is described in Example 1.
Is the same as

The formation of the hard coat resin film was carried out in the same manner as in Example 14, and the optical information recording / reproducing apparatus according to the present invention having an optical head (wavelength: 405 nm) equipped with a converging lens having NA of 0.85 was used. I tried to play the created disc. With the reproducing power set to 0.2 mW, once at a position of a radius of 55.5 mm, with the disc still,
When the focus pull-in operation was performed, the focus could be drawn much better than when the disk was rotated. Then, instantaneously, with the focus pulled in, the rotational linear velocity of the disk was increased to 1.7 m / s, and the disk was further moved to a radius of 56 mm to reproduce the reflected light from the information pits. 58m radius
In the region up to m, a good eye pattern signal could be reproduced.
The outermost portion of the disk has relatively large surface runout of the disk itself and a high probability of contact between the head and the medium during focus pull-in. However, as in this embodiment of the present invention, the focus pull-in By performing the operation, stable recording and reproduction can be realized.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be appropriately modified without departing from the gist of the present invention. Things. For example, it goes without saying that the present invention is also applied to devices in forms other than the optical disk shown here, their recording / reproducing methods, or optical disks and optical information recording media having configurations other than those described in the embodiments of the present application.

[0062]

As described above, the optical information recording medium according to the present invention is provided with the focus pull-in exclusive area having higher mechanical strength than other areas for performing the focus pull-in. Even if contact between the lens and the medium occurs due to external disturbance, damage to the medium can be suppressed. Also, even if contact between the lens of the optical head and the medium occurs during focus pull-in, the information recording area of the medium is not affected, so that an optical information recording medium suitable for highly reliable high-density recording is provided. Can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an optical information recording medium according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a read-only medium according to the present invention.

FIG. 3 is a sectional view showing an embodiment of a write-once medium according to the present invention.

FIG. 4 is a sectional view showing an embodiment of a magneto-optical medium according to the present invention.

FIG. 5 is a sectional view showing an embodiment of a phase change type medium according to the present invention.

FIG. 6 is a cross-sectional view showing a medium driving state for describing an optical information recording / reproducing method according to the present invention.

FIG. 7 is a schematic configuration diagram of an optical information recording / reproducing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording layer 21 Reflecting film 22 Information pit 23 Write-once recording film 24 Lower protective film 25 Magneto-optical recording film 26 Upper protective film 27 Phase change recording film 3 Cover layer 31 Adhesive layer 4 Hard coat layer 5 Optical head 51 Laser 52 Condenser lens 53 Focus error detection circuit 54 Tracking error detection circuit 55 Signal detection circuit 56 Actuator 57, 58, 59 Beam splitter 6 Motor 7 Laser driver 8 Servo circuit 9 Feed system 10 Optical information recording medium 101 Focus pull-in exclusive area 102 Information recording region

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 7/004 G11B 7/004 C 7/085 7/085 B 7/09 7/09 B F term (reference 5D029 LA02 LB04 LB08 LB13 LC13 5D090 AA01 BB02 BB03 BB04 CC01 CC04 CC09 CC14 DD01 FF05 GG25 HH01 LL04 5D117 AA02 CC01 CC04 CC05 CC07 DD03 5D118 AA14 AA16 BA01 BB01 BB02 BC05 BC14 BF12 BF12

Claims (13)

[Claims] 1. An optical information recording medium on which optically readable information is recorded, or on which information is optically recorded and which is optically readable.
An optical information recording medium, comprising: a focus pull-in-only area for performing an operation of converging a light beam having a small aperture having a higher mechanical strength than another area on an information recording surface. 2. An optical information recording medium on which optically readable information is recorded, or on which information is optically recorded and which is optically readable,
An optical information recording medium comprising a donut-shaped focus pull-in-dedicated area for performing an operation of condensing a light beam having a small diameter on an information recording surface. 3. The information recording surface is covered with a cover layer, and a hard coat layer having a higher hardness than the cover layer is formed on the cover layer in the focus pull-in exclusive area. 3. A method according to claim 1, wherein
The optical information recording medium according to the above. 4. The information recording surface is covered with a cover layer and a hard coat layer having a higher hardness than the cover layer.
The optical information recording medium according to claim 1, wherein the thickness of the hard coat layer in the focus pull-in exclusive area is larger than the thickness of another area of the hard coat layer. 5. The information recording surface is covered with a cover layer and a hard coat layer having a higher hardness than the cover layer.
The total thickness of the cover layer and the hard coat layer is constant, and the thickness of the hard coat layer in the focus pull-in exclusive region is larger than the thickness of other regions of the hard coat layer. 3. The optical information recording medium according to claim 1, wherein: 6. A substrate on which information pits are formed, a reflection film,
The recording medium according to claim 1, further comprising one of a phase change recording film, a magneto-optical recording film, and a write-once recording film.
6. The optical information recording medium according to any one of 5. 7. A reflective film, a lower protective film, a phase-change type recording film and an upper protective film, or a reflective film, a lower protective film, a magneto-optical recording film and an upper protective film, or a reflective film on a substrate. 6. The optical information recording medium according to claim 1, wherein any one of a type recording film is formed. 8. The optical information recording medium according to claim 7, wherein a tracking guide groove is formed on the substrate. 9. An optical information recording medium in the form of a disk, wherein the focus pull-in only area is provided inside the innermost circumference of the information recording area or between the information recording areas. 9. The optical information recording medium according to any one of claims 8 to 8. 10. A disc-shaped optical information recording medium, wherein the focus pull-in-dedicated area is provided between information recording areas and near the outermost periphery of the information recording area. 9. The optical information recording medium according to any one of claims 8 to 8. 11. A specific area on the optical information recording medium prior to an operation of reading or erasing information recorded on the optical information recording medium or prior to an operation of recording information on the optical information recording medium. An optical information recording / reproducing method, wherein a focus pull-in operation for condensing a light beam on an information recording surface of the area is performed using the method. 12. When the information recorded on the optical information recording medium is read or erased, or when the information is recorded on the optical information recording medium, the linear velocity of the optical information recording medium is V, and when the focus pull-in operation is performed. 12. The optical information according to claim 11, wherein when the linear velocity of the optical information recording medium is v, one of V = v> 0 V>v> 0 V> v = 0 is satisfied. Recording and playback method. 13. An optical information recording medium, comprising: a drive mechanism for driving the optical information recording medium; and an optical head for irradiating the optical information recording medium with a light beam, wherein the optical head emits a light beam emitted from the optical head. In an optical information recording / reproducing apparatus provided with an actuator for moving a position of a lens provided in the optical head so as to converge on an information recording surface of an information recording medium, the optical information recording / reproducing apparatus reproduces information, Prior to performing an erasing or recording operation, a mechanism for guiding the optical head onto a focus pull-in dedicated area set on the optical information recording medium is provided, and the actuator is driven on the focus pull-in dedicated area. Focus pull-in operation so that the light beam emitted by the optical head is focused on the information recording surface on the optical information recording medium. An optical information recording / reproducing apparatus characterized by being performed.