JP2866055B2 - Recording method of 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 having pits recorded by a laser beam and a recording method thereof.

[0002]

2. Description of the Related Art An optical information recording medium on which data can be recorded by irradiating a laser beam has a recording layer composed of a metal layer such as Te, Bi, Mn or the like, or a dye layer such as cyanine, merocyanine or phthalocyanine. A pit is formed by means of deformation, sublimation, evaporation or denaturation of the recording layer by laser light irradiation, and data is recorded. In an optical information recording medium having this recording layer, a gap is generally provided behind the recording layer to facilitate deformation, sublimation, evaporation or denaturation of the recording layer when forming pits. . Specifically, for example, a laminated structure called an air sandwich structure in which two substrates are laminated with a space portion interposed therebetween is employed. In this optical information recording medium, pits are formed by irradiating laser light from the transparent substrate 1 side. And when playing back the recorded data,
A laser beam having a lower power than that at the time of recording is irradiated from the substrate 1 side, and a signal is read based on a difference in reflected light between the pit and other portions.

On the other hand, a so-called ROM type optical information recording medium in which data is recorded in advance and data cannot be written or erased thereafter has already been widely put into practical use in the information processing and audio departments. This type of optical information recording medium has no recording layer as described above, and pits for reproducing recorded data are previously formed on a polycarbonate substrate by means such as pressing, and Au, Ag is formed thereon. , A reflective layer made of a metal film such as Cu, Al or the like is formed, and the reflective layer is further covered with a protective layer.

[0004] The most representative of the ROM type optical information recording medium is a compact disk, so-called CD, which is widely put into practical use in the audio department and the information processing department.
The specification of the recording and reproduction signals of D is standardized as a so-called CD format, and a reproduction apparatus conforming to this is very widely used as a compact disk player (CD player).

[0005]

It is strongly desired that the above-mentioned optical information recording medium has, for example, compatibility with a CD which has already become widespread and can be reproduced by a CD player at the time of reproduction. For that purpose, an optical information recording medium capable of obtaining a reproduction signal having a large modulation degree is required. However, the above-mentioned optical information recording medium has a recording layer which is not provided in a CD, and means for forming and recording pits on the recording layer, not on the substrate. Further, since the recording layer has a gap layer or the like for facilitating the formation of pits, the reproduced signal differs from the CD in terms of the reflectance of the laser beam, the modulation of the reproduced signal, and the like. In particular, a pit formed by irradiating a laser beam is not as clear as a pit formed mechanically like a press, so that it is difficult to obtain a large degree of modulation. For this reason, it is difficult to satisfy the CD format that defines the standard for a so-called CD, and it has not been possible to provide an optical disc that can be reproduced by a CD player.
The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an optical information recording medium capable of obtaining a reproduced signal having a high degree of modulation.

[0006]

According to the present invention, first, a light absorbing layer for absorbing a laser beam directly on a light-transmitting substrate or through another layer, and directly on the light absorbing layer. Alternatively, in an optical information recording medium in which a pit for reproducing data by laser light irradiation and a light reflecting layer for reflecting laser light through another layer are formed, the pit portion is adjacent to the light absorbing layer. The layer on the substrate side to be deformed is deformed, the portion of the light absorbing layer irradiated with the laser light is decomposed, and pits are formed at the position irradiated with the laser light. Further, the present invention is characterized in that the light absorbing layer of such an optical information recording medium is irradiated with laser light to form the pits as described above.

Here, by irradiating the light absorbing layer with a laser beam, the light absorbing layer absorbs the laser beam and generates heat, and is melted, evaporated, sublimated, deformed or denatured. Alternatively, a part of the components constituting the light absorbing layer diffuses or viscously flows into a layer adjacent to the same layer and mixes with components of the layer on the light-transmitting substrate side adjacent to the light absorbing layer. Is partially compounded. Alternatively, the interface between the light-absorbing layer and another layer adjacent to the light-absorbing layer is peeled off, and a void is formed there, or bubbles are generated in the light-absorbing layer and remain. ing.

In such an optical information recording medium, since a layer on the substrate adjacent to the light absorbing layer is locally deformed in the pit, a phase difference between the pit portion and the portion other than the pit portion is generated. Then, the incident laser spot is scattered, and a large difference occurs in the amount of reflected laser light. Therefore, the modulation degree of the reproduced signal can be increased.

In this case, regardless of whether the pit portion is deformed on the substrate side on the side of the light absorbing layer, whether it is convex or concave, the above-mentioned action is substantially the same. Further, in addition to the above-described deformation in the pit portion, the layer on the substrate side has an optical property changing portion in which the optical property is locally changed, or another layer adjacent to the same layer as the light absorbing layer. If a void is formed at the interface of the pit or fine bubbles are dispersed in the light absorbing layer at the pit, the pit and the pit may be affected by the phase difference, absorption, scattering, etc. of the laser spot. A large difference occurs depending on the reflected light amount of the laser beam from other portions, and the modulation degree of the reproduction signal can be increased.

[0010] Further, by providing an optical property modification portion having locally changed optical characteristics in a layer on the substrate adjacent to the light absorption layer in the pit portion, incident laser light is localized at the optical property modification portion. Due to the effects of phase difference, absorption, scattering, etc., a large difference occurs in the optical conditions, particularly the reflection of laser light, between the portion other than the pit and the pit portion. Can be increased.
In such an optical information recording medium in which pits are formed by deforming or changing the layer on the substrate adjacent to the light absorbing layer, a reflective layer can be provided in close contact behind the light absorbing layer.
A recordable optical information recording medium in which a reproduction signal for reading data conforms to, for example, the CD format can be easily obtained.

[0011]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings. FIG. 1 shows an example of a schematic structure of an optical information recording medium according to the present invention.
3 to FIG. In FIG. 1, reference numeral 1 denotes a light-transmitting substrate, and 2 denotes a light-absorbing layer formed thereon, which absorbs the irradiated laser light and generates heat, as described later.
This layer is for melting, evaporating, sublimating, deforming or denaturing, and forming pits 5 at the position irradiated with the laser spot. FIG. 2 shows a state before recording by a laser beam, and FIG.
After recording, that is, when the laser beam 7 was converged and irradiated onto the light absorbing layer 2 from the optical pickup 8, the surface of the light transmitting substrate 1 was partially deformed and / or changed, and the pits 5 were formed. The state is schematically shown.

When the light absorbing layer 2 is irradiated with a laser beam 7,
The irradiated part absorbs the laser beam 7 and generates heat,
The irradiated portion melts and decomposes, and at the same time, the layer adjacent thereto softens and melts. Some of the components constituting the light absorbing layer 2 diffuse or viscously flow into a layer adjacent to the light absorbing layer 2, and are mixed with components of the layer on the light transmitting substrate 1 side adjacent to the light absorbing layer 2. , Partially compound. Accordingly, the light absorbing layer 2
And a convex deformed portion 6 is formed on the surface of the layer adjacent to.
Such a phenomenon is mainly caused, for example, when one layer adjacent to the light absorption layer 2 is the light reflection layer 3 made of a metal layer and the other adjacent layer is the light transmissive substrate 1 made of a resin layer. Although it tends to occur on the light-transmitting substrate 1 side, deformation on the interface side with the light absorbing layer 2 may also occur on the light reflecting layer 3 side. In some cases, the deformed portion 6 may have a wavy shape on the light absorbing layer 2 side, or may have a concave shape.

The light-transmitting substrate 1 is made of a material having high transparency to laser light and mainly made of resin having excellent impact resistance, such as a polycarbonate plate, an acrylic plate, and an epoxy plate. The light absorbing layer 2 absorbs the laser light incident from the light transmitting substrate 1 side, generates heat, and melts and decomposes. For example, a cyanine dye such as indodicarbocyanine is coated on the substrate 1. Alternatively, it is formed by a spin coating method or the like via another layer formed thereon. The reflection layer 3 is formed of a metal film, for example, gold, silver, copper, aluminum, or an alloy film containing them. The protective layer 4 is made of a transparent substrate 1
And most commonly formed by applying a UV-curable resin by a spin coating method and irradiating the UV-curable resin with the UV-curable resin to cure the resin. In addition, epoxy resins, acrylic resins, silicone-based hard coat resins, and the like are generally used.

In the optical information recording medium according to the present invention, ρ = n given by the real part n _abs of the complex refractive index of the light absorbing layer 2, its thickness d _abs and the wavelength λ of the reproduction light.
_It is desirable that _abs d _abs / λ is 0.05 ≦ ρ ≦ 0.6 and that the imaginary part _kabs of the complex refractive index is 0.3 or less. This is to increase the reflectance with respect to the reproduction light, and when the above condition is satisfied, a high reflectance is obtained and the standard characteristics of 70% or more, which is defined in a CD format or the like, are sufficiently secured. it can.

FIGS. 4 to 8 schematically show examples of the state of the pits 5 formed by irradiating a laser beam. FIG. 4 schematically shows a state in which a spot 6 of a laser beam 7 is applied to the light absorbing layer 2 at the pit 5 to deform the substrate 1 adjacent to the light absorbing layer 2.

This will be described more specifically.
(A), when a laser spot is applied to the light absorbing layer 2, the components of the light absorbing layer 2 are melted and decomposed, and the interface side of the light transmitting substrate 1 with the light absorbing layer 2 is softened. This schematically shows a case where the deformation 6 is formed by the components of the light absorbing layer 2 being diffused or viscous flow toward the transparent substrate 1 side. The portion of the modification 6 is simultaneously formed with the light absorbing layer 2.
Is locally mixed with the material constituting the light-transmitting substrate 1 and partially combined, whereby the optical characteristics of the light-absorbing layer 2 and the light-transmitting substrate 1 are different from those of the light-absorbing layer 2 or the light-transmitting substrate 1. It may be the unit 12.

When the light absorbing layer 2 is irradiated with a laser spot in order to form the pits 5, the components forming the light absorbing layer 2 locally generate heat, melt and decompose at that portion. Usually, the optical characteristics also change locally. Furthermore, with such a phenomenon, physically, FIG.
As shown in (b), the interface between the light-absorbing layer 2 and another layer adjacent thereto, for example, the light-reflecting layer 3 is peeled off, and a void 10 is formed there, or the light-absorbing layer 2 Bubbles may be generated inside and may remain after cooling.

The air gap 10 as described above is formed by a layer adjacent to the side of the light absorbing layer 2 on which the laser beam 7 is incident, for example, the substrate 1 is located on the back side of the light absorbing layer 2, for example, the light reflecting layer 3 and the protective layer. The layer can be formed when the layer 4 is relatively easily deformed by heat and the binding property with the light absorbing layer 2 is lower in the latter than in the former. That is, in such an optical information recording medium, when the laser beam 7 of the light absorbing layer 2 is irradiated, energy is generated in the light absorbing layer 2 as described above, and the substrate 1 is deformed 6 at the same time. It is considered that gas is generated in the light absorbing layer 2, whereby the interface between the light absorbing layer 2 having poor binding properties and the light reflecting layer 3 adjacent thereto is separated, and the gas is accumulated there. . The gas generated inside the light absorbing layer 2 remains as bubbles 11.

FIGS. 4C and 4D show other shapes of the deformation 6 on the light-transmitting substrate 1 side. FIG. 4C shows that the top of the convex deformation 6 is split into two. (D) shows the state.
A wavy deformation 6 in which unevenness is alternately repeated is shown.
In these cases, the gap 10 and the bubble 1
1. The optically modified portion 12 may be formed. FIG. 8 shows that a laser spot is irradiated on the light absorbing layer 2 along the pre-groove 13 in order to form the pits 5 along the pre-groove 13 which is a tracking means formed on the surface of the translucent substrate 1. After that, a state in which the protective layer 4 and the light reflecting layer 3 are separated from the light transmitting substrate 1 and the light absorbing layer 2 is removed from the surface of the substrate 1 is schematically shown.

Further, STM (Scanning Tunneling Mic)
FIG. 9 shows an example of observing the state of the surface of the translucent substrate 1 along the pre-groove 13 using a microscope. In the drawing, the direction along the pregroove 13 of the tip (probe) 14, that is, the moving distance in the tracking direction is plotted on the horizontal axis, and the altitude of the surface of the translucent substrate 1 is plotted on the vertical axis. FIG. 9A shows a case where the distance between the pits is relatively short, that is, 10000 angstroms.
It can be seen that a 0 angstrom convex clear deformation 6 is formed. FIG. 6B shows a case where the distance between the pits is relatively long at 40,000 angstroms. Here, a convex deformation 6 having a height of about 200 angstroms is recognized, but the intermediate portion of this deformation is slightly lower. It can be seen that the peak of deformation 6 is divided into two.

FIG. 5 schematically shows a case where the deformation 6 of the light-transmitting substrate 1 adjacent to the light absorbing layer 2 at the pit 5 is formed in a concave shape with respect to the light absorbing layer 2. FIG.
(A) shows a gap 10 at the boundary between the light absorbing layer 2 and the light reflecting layer 3.
. FIG. 3B shows the case where fine bubbles 11, 11... Are dispersed in the light absorbing layer 2 at the same time when the voids 10 are formed, and the deformation 6 is further reduced. The decomposed component of the light absorbing layer 2 diffuses into the formed light-transmitting substrate 1, and this component and the component constituting the light-transmitting substrate 1 are mixed and partially combined to form the optical property modifying portion 12. Are formed. Further, FIG.
Is formed, and at the same time, a gap 10 ′ is formed between the substrate 1 and the light absorbing layer 2.

FIG. 6 shows deformations 6 and 6 ′ in the pit 5.
Indicates a case in which both layers are adjacent to the light absorption layer 2. Such pits are often formed when the layers on both sides sandwiching the light absorbing layer 2, for example, the substrate 1 and the light reflecting layer 2 and the protective layer 4 have substantially the same thermal deformation temperature or hardness. FIG. 6A shows a case where a gap 10 ′ is formed between the light absorbing layer 2 and the substrate 1 in the pit 5, and FIG. FIG. 3C shows a case where voids 10, 10 ′ are formed between the light-absorbing layer 2 and the light-reflecting layer 3. Are respectively shown. FIG. 6D shows a modification 6 on the side of the translucent substrate 1 and the light reflecting layer 3.
6 'shows a state in which each of them is formed in a convex shape toward the light absorbing layer 2 side.

Further, FIG. 7 shows that the layer on the side where the laser beam 7 is incident with respect to the light absorbing layer 2 has an optical property altering section 13 in which the optical property is changed in the pit 5 from the other portions. Is the case. This denaturing section 13 is always
This often reaches the inside of the light absorbing layer 2. In this case, deformation 6 of the layer adjacent to the light absorption layer 2 may be seen, but the deformation is generally unclear due to the presence of the optical property modification portion 13.

FIG. 7A shows a state in which an optical property modifying portion 13 is formed adjacent to the light absorbing layer 2, for example, in a portion of the substrate 1, and FIG. This shows a state in which the optical characteristics gradually change in the thickness direction of the layer 2. Such denaturation of each layer is formed by the action of heat generated when the light absorbing layer 2 is irradiated with the laser beam 7, whereby the light absorbing layer 2 and other layers are decomposed, reacted, and mutually diffused. Therefore, such pits 5 are formed when a material having such an action is selected for the light absorbing layer 2 and the layer adjacent thereto.

Further, specific examples of the present invention will be described below. (Example 1) 0.8 μm in width, 0.08 μm in depth,
A spiral pre-groove 8 having a pitch of 1.6 μm is formed, having a thickness of 1.2 mm, an outer diameter of 120 mmφ, and an inner diameter of 15 mm.
A mmφ polycarbonate substrate 1 was molded by an injection molding method. Rockwell hardness ASTM D785 of this polycarbonate substrate 1 is M75 (equivalent to pencil hardness HB), and heat distortion temperature ASTM D648 is 4.6.
kg / cm ² and 121 ° C.

As an organic dye for forming the light absorbing layer 2, 0.65 g of 1,1′-dibutyl 3,3,3 ′, 3 ′
Tetramethyl 4,5,4 ', 5' dibenzoindodicarbocyanine perchlorate (manufactured by Nippon Kogaku Dyestuff Research Laboratory, product number NK3219) was added to diacetone alcohol solvent 10c.
c, and this was applied to the surface of the substrate 1 by spin coating to form a light absorbing layer 2 having a thickness of 130 nm.

Next, the diameter of this disk is 45 to 118 m.
The film thickness is 80
An Au film having a thickness of 3 nm was formed, and the reflective layer 3 was formed. further,
An ultraviolet curable resin was spin-coated on the reflective layer 3 and irradiated with ultraviolet light to be cured, thereby forming a protective layer 4 having a thickness of 10 μm. The Rockwell hardness ASTM D785 after curing of the protective layer 4 is M90, and the heat deformation temperature ASTM D648 is 4.6 kg / cm ² , 135 ° C.
Met.

The optical disk thus obtained has a wavelength of 78
A 0 nm semiconductor laser was irradiated at a linear velocity of 1.2 m / sec at a recording power of 6.0 mW to record an EFM signal. After that, this optical disc is loaded onto a commercially available CD player (Aure
x XR-V73, the reproduction light wavelength λ = 780 nm), the reflectivity of the semiconductor laser was 72%, and I ₁₁ /
I _top was 0.68, I ₃ / I _top was 0.35, and the block error rate BLER was 1.2 × 10 ⁻² .

According to the CD standard, the reflectance is 70% or more, and I ₁₁
/ I _top is 0.6 or more, I ₃ / I _top is 0.3 to 0.7,
The block error rate BLER is determined to be 3 × 10 ⁻² or less, and the optical disc according to this embodiment satisfies this standard. Further, the protective layer 4 and the light reflecting layer 3 of the optical disk after recording are peeled off, the light absorbing layer 2 is washed and removed with a solvent, and the surface of the light transmitting substrate 1 is subjected to STM (Scanni).
When observed with an ng Tunneling Microscope), convex deformation was observed at the pits.

(Example 2) In Example 1, except that an epoxy resin was spin-coated between the light absorbing layer 2 and the light reflecting layer 3 to provide a hard layer having a thickness of 100 nm.
An optical disk was manufactured in the same manner as in Example 1. The Rockwell hardness AST after curing of this epoxy resin
M D785 is M90 and the heat distortion temperature ASTM D
648 was 4.6 kg / cm ² , 135 ° C.

An EFM signal was recorded on the thus obtained optical disc in the same manner as in the first embodiment. After that, when this optical disc was reproduced by a commercially available CD player, the reflection of the semiconductor laser was the same as in the first embodiment. Rate and playback signal output characteristics, and furthermore, the block error rate BLER
Was 3.0 × 10 ⁻³ . When the surface of the light-transmitting substrate 1 of the optical disk after recording was observed with an STM (Scanning Tunneling Microscope) in the same manner as in Example 1, a convex deformed portion 6 was observed. The middle of the deformed portion 6 was slightly lower, and it was confirmed that the peak of deformation was divided into two.

(Example 3) In Example 1, a 100 nm thick silicon acryl was used between the light absorbing layer 2 and the light reflecting layer 3 and instead of the epoxy resin formed on the upper surface of the light absorbing layer 2. An optical disk was manufactured in the same manner as in Example 1 except that a hard layer of resin was provided, and a binding layer of 20 nm made of epoxy resin was formed on the upper surface of the hard layer by spin coating. The Rockwell hardness ASTM D after curing the silicone acrylic resin layer
785 is M100, heat distortion temperature ASTM D64
8 was 4.6 kg / cm ² and 100 ° C.

An EFM signal was recorded on the thus obtained optical disc at a recording power of 7.0 mW in the same manner as in the first embodiment. Thereafter, this optical disc was loaded into the same CD player (Aurex XR-V73, When reproduction was performed at a wavelength of 780 nm of the reproduction light, the reflectivity of the semiconductor laser was 75%, I ₁₁ / I _top was 0.63, and I ₃ / I _top was 0.
35, block error rate BLER is 2.5 × 10 ^-3
Met. Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is STM (Scanning T).
When observed with an unneling microscope, the same state as in Example 1 was confirmed.

(Embodiment 4) In Embodiment 1, an alloy film of gold and antimony having a ratio of 9: 1 was formed on the light absorbing layer 2 by a vacuum evaporation method as the light reflecting layer 3, and On this reflective layer 3, 20 nm of epoxy resin
An optical disc was manufactured in the same manner as in Example 1 except that the protective layer 4 made of an ultraviolet-curable resin was formed via the binder layer. The light reflection layer 3 has a pencil hardness of "H" or more.

An EFM signal was recorded on the thus obtained optical disc at a recording power of 6.2 mW in the same manner as in the first embodiment. Thereafter, this optical disc was reproduced by the same CD player as in the first embodiment. The reflectance of the laser is 72%, I ₁₁ / I _top is 0.62, and I ₃ / I _top is 0.2.
32, block error rate BLER is 3.5 × 10 ^-3
Met. Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is STM (Scanning T).
When observed with an unneling microscope, the same state as in Example 1 was confirmed.

Example 5 In Example 1, the surface of the polycarbonate substrate 1 was spin-coated with a UV-curable hard coat resin on the light incident side, provided with a 1 μm-thick substrate protection layer, and provided with a pre-groove. The light-absorbing layer 2 was formed thereon, and a 3: 1 alloy film of iridium and gold was formed as a light-reflective layer 3 on the light-absorbing layer 2 by a sputtering method. An optical disk was manufactured in the same manner as in Example 1. The light reflection layer 3 has a pencil hardness of “5H” or more.

An EFM signal was recorded on the thus obtained optical disc in the same manner as in the first embodiment. After that, when this optical disc was reproduced by the same CD player as in the first embodiment, the reflectance of the semiconductor laser was 70%. %, I ₁₁ / I
_{The top} was 0.62, the I ₃ / I _top was 0.37, and the block error rate BLER was 3.7 × 10 ⁻³ . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is applied to an STM (Scanning Tunneling Microscop).
When observed in e), the same state as in Example 1 was confirmed.

(Example 6) In Example 1, the light reflection layer 3 was formed of a silver film having a thickness of 60 nm, and a silicone-based hard coat agent was spin-coated thereon, followed by heating and curing. An optical disk was manufactured in the same manner as in Example 1 except that the hard protective layer 4 having a thickness of 3 μm was formed. The protective layer 4 has a pencil hardness of “HB”.
It has the above hardness.

An EFM signal was recorded on the thus obtained optical disc in the same manner as in the first embodiment. After that, when this optical disc was reproduced by the same CD player as that in the first embodiment, the reflectance of the semiconductor laser was 71%. , I ₁₁ / I _top was 0.63, I ₃ / I _top was 0.35, and the block error rate BLER was 2.8 × 10 ⁻³ . Further, in the same manner as in the first embodiment, the light-transmitting substrate 1
When the surface of the sample was observed with an STM (Scanning Tunneling Microscope), the same state as in Example 1 was confirmed.

Example 7 In Example 1, a polysulfide-added epoxy resin diluted with diglycidyl ether was spin-coated on the light reflecting layer 3 on which a 50 nm-thick Au film was vacuum-deposited. An optical disc was manufactured in the same manner as in Example 1 except that a silicone-based hard coat agent was spin-coated through a 30-nm binding layer, and this was heated and cured to form a hard protective layer 4 having a thickness of 3 μm. did.

An EFM signal was recorded on the optical disk thus obtained in the same manner as in the first embodiment. After that, when this optical disk was reproduced by the same CD player as in the first embodiment, the reflectance of the semiconductor laser was 72%. , I ₁₁ / I _top was 0.65, I ₃ / I _top was 0.35, and the block error rate BLER was 2.5 × 10 ⁻³ . Further, in the same manner as in the first embodiment, the light-transmitting substrate 1
When the surface of the sample was observed with an STM (Scanning Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 8)
1 'dibutyl 3, 3, 3', 3 'tetramethyl 5, 5'
The light-absorbing layer 2 was formed using diethoxyindodicarbocyanine iodide, a 100-nm hard layer made of epoxy resin was formed on the light-reflective layer 3, and an ultraviolet-curing resin was further provided thereon by 10 μm. An optical disk was manufactured in the same manner as in Example 1 except that the protective layer 4 was formed.

An EFM signal was recorded on the optical disk thus obtained in the same manner as in the first embodiment. After that, when this optical disk was reproduced by the same CD player as that in the first embodiment, the reflectivity of the semiconductor laser was 74%. , I ₁₁ / I _top was 0.68, I ₃ / I _top was 0.34, and the block error rate BLER was 8.3 × 10 ⁻³ . Further, in the same manner as in the first embodiment, the light-transmitting substrate 1
When the surface of the sample was observed with an STM (Scanning Tunneling Microscope), the same state as in Example 1 was confirmed.

Ninth Embodiment The procedure of the first embodiment is the same as that of the first embodiment except that an ultraviolet-curing hard coat resin is spin-coated on the light incident side of the polycarbonate substrate 1 to provide a 1 μm-thick substrate protection layer. An optical disk was manufactured in the same manner as in Example 1. An EFM signal was recorded on the optical disk thus obtained in the same manner as in the first embodiment.
When this optical disc was reproduced with the same CD player as in the first embodiment, the reflectance of the semiconductor laser was 70% and I ₁₁
/ I _top was 0.62, I ₃ / I _top was 0.37, and the block error rate BLER was 1.3 × 10 ^-2 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is STM (Scanning Tunneling Mic).
(roscope), the same state as in Example 1 was confirmed.

Example 10 In Example 1, a polybutadiene resin dissolved in cyclohexane was spin-coated between the light absorbing layer 2 and the reflecting layer 3 to a thickness of 10 nm.
An optical disk was manufactured in the same manner as in Example 1 except that the polybutadiene resin layer was provided. The optical disk thus obtained was subjected to EFM in the same manner as in the first embodiment.
A signal was recorded, and then this optical disk was reproduced by the same CD player as in the first embodiment. As a result, the reflectance of the semiconductor laser was 72%, I ₁₁ / I _top was 0.65, and I ₃ / I
_Top is 0.35, block error rate BLER is 8.
It was 6 × 10 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is
(Scanning Tunneling Microscope), the same state as in Example 1 was confirmed.

Example 11 The same polycarbonate substrate 1 as used in Example 1 was spin-coated with an acrylic resin dissolved with diisobutyl ketone on the surface thereof.
A resin layer (not shown) having a thickness of 40 nm was formed. The Rockwell hardness ASTM D785 of this resin layer is M85
And the heat distortion temperature ASTM D648 is 4.6 kg.
/ Cm ² and 100 ° C.

As an organic dye for forming the light absorbing layer 2, 0.6 g of 1,1′-dipropyl, 3,3,3 ′,
3 ′ tetramethyl 5,5 ′ dimethoxyindodicarbocyanine iodide was added to isopropyl alcohol solvent 1
The solution was dissolved in 0 cc, and the solution was applied to the surface of the substrate 1 by spin coating to form a light absorbing layer 2 having a thickness of 120 nm. The real part n _abs of the complex refractive index of the light absorbing layer 2
Ρ given by the following _formula and its film thickness d _abs and the wavelength λ of the reproduction light:
n _abs d _abs / λ was 0.41, and the imaginary part k _abs of the complex refractive index was 0.02.

Next, a silicon acrylic resin dissolved in cyclohexane was spin-coated thereon to form a
m hard layers were formed. This hard layer has a pencil hardness of 2H,
Heat deformation temperature ASTM D648 4.6 kg / cm ² , 1
20 ° C. An Au film having a thickness of 50 nm was formed on the hard layer by a sputtering method, and the reflective layer 3 was formed. Further, an ultraviolet curable resin was spin-coated on the reflective layer 3 and irradiated with ultraviolet light to be cured, thereby forming a protective layer 4 having a thickness of 10 μm. The Rockwell hardness ASTM D785 after curing of the protective layer 4 is M90, and the heat deformation temperature ASTM D648 is 4.6 kg / c.
m ² , 135 ° C.

The optical disk thus obtained has a wavelength of 78
A 0 nm semiconductor laser was irradiated at a linear velocity of 1.2 m / sec at a recording power of 7.5 mW to record an EFM signal. Thereafter, when this optical disk was reproduced by the same CD player as in Example 1, the reflectance of the semiconductor laser was 74%, and I ₁₁
/ I _top was 0.62, I ₃ / I _top was 0.31, and the block error rate BLER was 4.0 × 10 ⁻³ . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is STM (Scanning Tunneling Mic).
(roscope), the same state as in Example 1 was confirmed.

(Embodiment 12) In Embodiment 11,
Spin coat a silicone coating agent on the resin layer,
An optical disc was manufactured in the same manner as in Example 11, except that a silicate layer having a thickness of 0.01 μm was provided, and the light absorbing layer 2 was formed thereon. A recording power of 7.8 was applied to the optical disk thus obtained in the same manner as in the eleventh embodiment.
When an EFM signal was recorded at mW, and then this optical disk was reproduced by the same CD player as in Example 11,
Semiconductor laser reflectivity 73%, I ₁₁ / I _top 0.6
2, I ₃ / I _top is 0.31, block error rate BL
The ER was 3.4 × 10 ⁻³ . When the surface of the light-transmitting substrate 1 of the optical disk after recording was observed with an STM (Scanning Tunneling Microscope) in the same manner as in Example 1, the same state as in Example 1 was confirmed.

(Thirteenth Embodiment) In the eleventh embodiment,
A glass substrate was used as the substrate 1, and a 20 nm-thick binding layer formed by spin coating an isocyanate resin dissolved in a 1: 1 solvent of toluene and methyl ethyl ketone was formed on the reflective layer. An optical disk was manufactured in the same manner as in Example 11 except for the above. An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.2 mW in the same manner as in the eleventh embodiment. Thereafter, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Rate is 72%, I
₁₁ / I _top was 0.65, I ₃ / I _top was 0.33, and the block error rate BLER was 3.6 × 10 ⁻³ . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is STM (Scanning Tunneling Mic).
(roscope), the same state as in Example 1 was confirmed.

(Embodiment 14) In the eleventh embodiment,
Spin coat a silicone coating agent on the resin layer,
A silicate layer having a thickness of 0.01 μm was provided, a light absorbing layer 2 was formed thereon, and a binding layer having a thickness of 20 nm formed by spin coating polybutadiene was formed on the light reflecting layer 3. An optical disk was manufactured in the same manner as in Example 11 except for the above.

An EFM signal was recorded on the thus obtained optical disk at a recording power of 7.2 mW in the same manner as in the eleventh embodiment. Thereafter, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Laser reflectivity is 72%, I ₁₁ / I _top is 0.66, I ₃ / I _top is 0.35, and block error rate BLER is 3.5 × 1.
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 15)
Example 11 except that the thickness of the resin layer was set to 20 nm, no silicon acrylic resin layer was provided, and an alloy film of iridium and gold having a ratio of 1: 9 was formed as the reflective layer 3 by a sputtering method. An optical disk was manufactured in the same manner as described above. The alloy film has a pencil hardness of 2
H.

An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.0 mW in the same manner as in the eleventh embodiment. Thereafter, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Laser reflectivity 71%, I ₁₁ / I _top 0.63, I ₃ / I _top 0.32, block error rate BLER 3.3 × 1
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 16) In the eleventh embodiment,
Spin coat a silicone coating agent on the resin layer,
A silicate layer having a thickness of 0.01 μm was provided, a light absorbing layer 2 was formed thereon, no silicon acrylic resin layer was provided, and a 1: 9 mixture of iridium and gold was used as the reflective layer 3.
An optical disc was manufactured in the same manner as in Example 11 except that an alloy film having the following ratio was formed by a sputtering method.

An EFM signal was recorded on the thus obtained optical disk at a recording power of 7.8 mW in the same manner as in the eleventh embodiment. Thereafter, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Laser reflectance 71%, I ₁₁ / I _top 0.64, I ₃ / I _top 0.32, block error rate BLER 2.8 × 1
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 17) In Embodiment 11,
A silicon acrylic resin layer was not provided, an alloy film of iridium and gold having a ratio of 1: 9 was formed as a reflective layer 3 by a sputtering method, and on the light reflective layer,
Polyisoprene is spin-coated to form a binding layer having a thickness of 20 nm, and a protective layer 4 made of an ultraviolet curable resin is formed thereon.
Except that was formed in the same manner as in Example 11 above.
An optical disk was manufactured.

An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.4 mW in the same manner as in the eleventh embodiment. After that, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Laser reflectivity is 72%, I ₁₁ / I _top is 0.64, I ₃ / I _top is 0.32, and block error rate BLER is 4.1 × 1.
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 18) In the eleventh embodiment,
That no silicon acrylic resin layer is provided, that a copper film having a thickness of 50 nm is formed as the reflective layer 3, and that the protective layer 4
Spin-coated bisphenol-curable epoxy resin diluted in diglycidyl ether solvent to a thickness of 5 μm
Example 1 except that the epoxy resin layer of Example 1 was formed.
An optical disk was manufactured in the same manner as in Example 1. The protective layer has a Rockwell hardness ASTM D785 of M110.
Therefore, it has a function as a hard layer.

An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.0 mW in the same manner as in the eleventh embodiment. Thereafter, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Laser reflectance 75%, I ₁₁ / I _top 0.64, I ₃ / I _top 0.33, block error rate BLER 2.9 × 1
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 19) In the embodiment 11 described above,
Spin coat a silicone coating agent on the resin layer,
A 0.01 μm-thick silicate layer, a light-absorbing layer 2 formed thereon, no silicon-acrylic resin layer provided, a 50 nm-thick copper film formed as a reflective layer 3, and a protective layer 4 An optical disk was manufactured in the same manner as in Example 11 except that a bisphenol-curable epoxy resin diluted in a diglycidyl ether solvent was spin-coated to form a 5 μm-thick epoxy resin layer.

An EFM signal was recorded on the thus obtained optical disk at a recording power of 7.0 mW in the same manner as in the eleventh embodiment. Thereafter, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Laser reflectance is 74%, I ₁₁ / I _top is 0.64, I ₃ / I _top is 0.33, and block error rate BLER is 3.5 × 1.
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Example 20) In Example 11,
A foaming agent was mixed into an acrylic resin, a silicon acrylic resin layer was not provided, a copper film having a thickness of 50 nm was formed as a reflective layer 3 by a vacuum evaporation method, and a 6: 4 mixture of toluene and methyl ethyl ketone was formed on the reflective layer. 20nm thick formed by spin coating polyvinyl acetate resin dissolved in solvent
That the protective layer 4 was formed via the binder layer, and the protective layer 4 was spin-coated with a bisphenol-curable epoxy resin diluted in a diglycidyl ether solvent to a thickness of 5 μm.
An optical disc was manufactured in the same manner as in Example 11 except that an m-th epoxy resin layer was formed.

An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.4 mW in the same manner as in the eleventh embodiment. Thereafter, the optical disk was reproduced by the same CD player as in the eleventh embodiment. Laser reflectance is 74%, I ₁₁ / I _top is 0.64, I ₃ / I _top is 0.33, and block error rate BLER is 3.6 × 1.
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

EXAMPLE 21 A spiral pre-groove 8 having a width of 0.8 μm, a depth of 0.08 μm, and a pitch of 1.6 μm was formed on the surface, a thickness of 1.2 mm, and an outer diameter of 120 m.
As an organic dye for forming the light absorbing layer 2 on a glass substrate 1 having a diameter of 15 mmφ and a diameter of 0.5 g,
1 ', dipropyl 3, 3, 3', 3 'tetramethyl 5,
5 ′ diethoxyindodicarbocyanine perchlorate was dissolved in 10 cc of a dichloroethane solvent, and the solution was applied to the surface of the substrate 1 by spin coating to form a light absorption layer 2 having a thickness of 100 nm.

Next, the diameter of this disk is 45 to 118 m.
A film thickness of 50 m
An Au film having a thickness of 3 nm was formed, and the reflective layer 3 was formed. further,
A urethane resin dissolved with methyl ethyl ketone is spin-coated to a thickness of 100 nm on the reflective layer 3 to form a buffer layer, and an ultraviolet-curable resin is spin-coated thereon and irradiated with ultraviolet light to be cured. A protective layer 4 having a thickness of 10 μm was formed.

The optical disk thus obtained has a wavelength of 78
A 0 nm semiconductor laser was irradiated at a linear velocity of 1.2 m / sec and a recording power of 7.2 mW to record an EFM signal. After that, this optical disc is loaded onto a commercially available CD player (Aure
x XR-V73, the wavelength of the reproduction light λ = 780 nm), the reflectivity of the semiconductor laser was 77%, and I ₁₁ /
I _top was 0.65, I ₃ / I _top was 0.33, and the block error rate BLER was 3.0 × 10 ⁻³ . Also,
In the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is STM (Scanning Tunneling Microsc
ope), the same state as in Example 1 was confirmed.

Example 22 A spiral pre-groove 8 having a width of 0.8 μm, a depth of 0.08 μm and a pitch of 1.6 μm was formed on the surface, a thickness of 1.2 mm, and an outer diameter of 120 m.
A polycarbonate substrate 1 having mφ and an inner diameter of 15 mmφ was injection molded. As an organic dye for forming the light absorbing layer 2, 0.5 g of 1,1 ′, dipropyl 3,3,3 ′,
3 ′ tetramethyl 5,5 ′ diethoxyindodicarbocyanine perchlorate is dissolved in 10 cc of an isopropyl alcohol solvent, and the solution is applied to the surface of the substrate 1 by spin coating to form a light absorbing layer having a thickness of 100 nm. 2
Was formed. Further, an SiO ₂ film was formed thereon to a thickness of 40 nm by a sputtering method.

Next, the diameter of this disk is 45 to 118 m.
A film thickness of 50 m
An Au film having a thickness of 3 nm was formed, and the reflective layer 3 was formed. further,
A urethane resin dissolved with methyl ethyl ketone is spin-coated to a thickness of 100 nm on the reflective layer 3 to form a buffer layer, and an ultraviolet-curable resin is spin-coated thereon and irradiated with ultraviolet light to be cured. A protective layer 4 having a thickness of 10 μm was formed.

The optical disk thus obtained has a wavelength of 78
A 0 nm semiconductor laser was irradiated at a linear velocity of 1.2 m / sec at a recording power of 6.8 mW to record an EFM signal. After that, this optical disc is loaded onto a commercially available CD player (Aure
x XR-V73, the wavelength of the reproduction light λ = 780 nm), the reflectivity of the semiconductor laser was 77%, and I ₁₁ /
I _top was 0.66, I ₃ / I _top was 0.36, and the block error rate BLER was 3.5 × 10 ⁻³ . Also,
In the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is STM (Scanning Tunneling Microsc
ope), the same state as in Example 2 was confirmed.

(Embodiment 23) In the above embodiment 22,
An optical disk was manufactured in the same manner as in Example 22 except that the SiO ₂ film was formed by the LPD method, and that a dioxane solvent was used as a solvent of the coating agent when forming the light absorbing layer 2. A recording power of 7.2 was applied to the optical disk thus obtained in the same manner as in Example 22.
An EFM signal was recorded at mW, and then this optical disc was reproduced by the same CD player as in Example 22.
Semiconductor laser reflectivity of 77%, I ₁₁ / I _top of 0.6
6, I ₃ / I _top is 0.35, block error rate BL
The ER was 4.0 × 10 ⁻³ . When the surface of the light-transmitting substrate 1 of the optical disk after recording was observed with an STM (Scanning Tunneling Microscope) in the same manner as in Example 1, the same state as in Example 1 was confirmed.

(Embodiment 24) In the above embodiment 22,
Instead of the SiO ₂ film, an epoxy resin dissolved in diglycidyl ether was spin-coated to form an epoxy resin layer having a thickness of 100 nm. As the reflective layer 3, an alloy thin film layer of gold and titanium in a ratio of 9: 1 was used. Was formed, and a polybutadiene resin dissolved in cyclohexane was spin-coated between the light absorbing layer 2 and the reflective layer 3 to obtain a thickness of 12
An optical disc was manufactured in the same manner as in Example 22 except that a 0-nm polybutadiene resin layer was provided.

An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.0 mW in the same manner as in Example 22. Thereafter, the optical disk was reproduced by the same CD player as in Example 22. Laser reflectance is 74%, I ₁₁ / I _top is 0.64, I ₃ / I _top is 0.33, and block error rate BLER is 2.5 × 1
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 25) In the embodiment 22 described above,
Instead of the SiO ₂ film, an epoxy resin dissolved in diglycidyl ether was spin-coated to form an epoxy resin layer having a thickness of 100 nm. As the reflective layer 3, an alloy thin film layer of gold and titanium in a ratio of 9: 1 was used. Was formed, and a polybutadiene resin dissolved in cyclohexane was spin-coated between the light absorption layer 2 and the reflection layer 3 to obtain a thickness of 120 n.
Example 22 except that a polybutadiene resin layer having a thickness of 20 m was provided and that a bisphenol-curable epoxy resin was spin-coated to a thickness of 20 nm between the light reflection layer and the protective layer 4 in order to enhance the binding property. An optical disk was manufactured in the same manner as described above.

An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.2 mW in the same manner as in Example 22. Thereafter, this optical disk was reproduced by the same CD player as in Example 22. Laser reflectance is 74%, I ₁₁ / I _top is 0.64, I ₃ / I _top is 0.33, and block error rate BLER is 3.0 × 1.
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 26) In embodiment 22 above,
In place of the SiO ₂ film, an epoxy resin dissolved in diglycidyl ether was spin-coated to form an epoxy resin layer having a thickness of 100 nm. The epoxy resin layer was dissolved in cyclohexane between the epoxy resin layer and the reflective layer 3. A polybutadiene resin was spin-coated to provide a polybutadiene resin layer having a thickness of 120 nm, and the protective layer had a thickness of 5 μm.
An optical disc was manufactured in the same manner as in Example 22 except that the above-mentioned was used.

An EFM signal was recorded on the thus obtained optical disc at a recording power of 7.2 mW in the same manner as in the twenty-second embodiment. Thereafter, the optical disc was reproduced by the same CD player as in the twenty-second embodiment. Laser reflectance is 74%, I ₁₁ / I _top is 0.64, I ₃ / I _top is 0.32, and block error rate BLER is 3.3 × 1.
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 27) In the above embodiment 22,
Does not form a SiO ₂ film, between the light absorbing layer 2 and the reflective layer 3, the polybutadiene resin dissolved in cyclohexane was spin-coated, provided with a polybutadiene resin layer having a thickness of 120 nm, the reflective layer and the protective layer 4 In the same manner as in Example 22, except that a bisphenol-curable epoxy resin was spin-coated to a thickness of 20 nm in the meantime and the thickness of the protective layer was set to 5 μm in order to enhance the binding property to the optical disk. Was made.

An EFM signal was recorded on the thus obtained optical disk at a recording power of 7.2 mW in the same manner as in the twenty-second embodiment. Thereafter, this optical disk was reproduced by the same CD player as in the twenty-second embodiment. Laser reflectivity is 74%, I ₁₁ / I _top is 0.63, I ₃ / I _top is 0.32, and block error rate BLER is 2.8 × 1.
It was 0 ^-3 . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disc after recording is STM (Scanni).
ng Tunneling Microscope), the same state as in Example 1 was confirmed.

(Embodiment 28) In the above embodiment 22,
Example 2 except that the SiO ₂ film was not formed.
An optical disk was manufactured in the same manner as in No. 2. An EFM signal was recorded on the optical disk thus obtained at a recording power of 7.2 mW in the same manner as in Example 22. Thereafter, the optical disk was reproduced by the same CD player as in Example 22. The rate is 77%, I ₁₁ / I
_{The top} was 0.66, the I ₃ / I _top was 0.35, and the block error rate BLER was 1.0 × 10 ⁻² . Further, in the same manner as in the first embodiment, the surface of the light-transmitting substrate 1 of the optical disk after recording is applied to an STM (Scanning Tunneling Microscop).
When observed in e), the same state as in Example 1 was confirmed.

Example 29 A spiral pre-groove 8 having a width of 0.4 μm, a depth of 0.1 μm, and a pitch of 0.8 μm was formed on the surface, having a thickness of 1.2 mm and an outer diameter of 120 mm.
A polycarbonate substrate 1 having an inner diameter of 15 mmφ was formed by an injection molding method. Rockwell hardness ASTM D785 of this polycarbonate substrate 1 is M75 (equivalent to pencil hardness HB), and heat deformation temperature ASTM D648.
Was 4.6 kg / cm ² and 121 ° C.

As an organic dye for forming the light absorbing layer 2, 0.65 g of 1,1 ′ dibutyl 3,3,3 ′, 3 ′
Tetramethyl 4,5,4 ′, 5 ′ dibenzoindomonocarbocyanine perchlorate is dissolved in 10 cc of a diacetone alcohol solvent, and this is dissolved on the surface of the substrate 1.
The light-absorbing layer 2 having a thickness of 100 nm was formed by spin coating.

Next, the diameter of this disk is 45 to 118 m.
The film thickness is 80
An Au film having a thickness of 3 nm was formed, and the reflective layer 3 was formed. further,
An ultraviolet curable resin was spin-coated on the reflective layer 3 and irradiated with ultraviolet light to be cured, thereby forming a protective layer 4 having a thickness of 10 μm. The Rockwell hardness ASTM D785 after curing of the protective layer 4 is M90, and the heat deformation temperature ASTM D648 is 4.6 kg / cm ² , 135 ° C.
Met.

The optical disk thus obtained has a wavelength of 67
A 0 nm semiconductor laser was irradiated at a linear velocity of 2.0 m / sec and a recording power of 8.0 mW to record an EFM signal. Then, when this optical disk was reproduced, the reflectance of the semiconductor laser was 70%, I ₁₁ / I _top was 0.70, I ₃ / I _top
Was 0.32.

In the optical disk according to this embodiment, recording with a large degree of modulation could be performed. Further, the protective layer 4 and the light reflecting layer 3 of the optical disk after the recording were separated, the light absorbing layer 2 was washed and removed with a solvent, and the surface of the light transmitting substrate 1 was analyzed. Decomposition was confirmed. When the surface was observed with an STM (Scanning Tunneling Microscope), convex deformation was observed at the pits.

[0087]

As described above, according to the optical information recording medium of the present invention, it is possible to form pits from which a reproduced signal having a high modulation degree can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic half sectional perspective view showing an example of the structure of an optical information recording medium.

FIG. 2 is a partially enlarged view of a section of the optical information recording medium of FIG. 1 taken along a track before optical recording.

FIG. 3 is a partially enlarged view of a cross section along a track after optical recording of the optical information recording medium of FIG. 1;

FIG. 4 is an enlarged cross-sectional view of a main part taken along a track to show an example of a pit of an optical information recording medium.

FIG. 5 is an enlarged cross-sectional view of a main part taken along a track to show another example of a pit of an optical information recording medium.

FIG. 6 is an enlarged cross-sectional view of a main part taken along a track to show another example of a pit of an optical information recording medium.

FIG. 7 is an enlarged cross-sectional view of a main part taken along a track to show another example of the optical information recording medium pit.

FIG. 8 is an enlarged perspective view of a main part showing a surface of a light transmitting substrate of the optical information recording medium after recording.

FIG. 9 shows the surface of the translucent substrate as STM (Scanning Tun).
7 is an example of a graph showing a relationship between a moving distance of a chip along a tracking direction and an altitude when observed by a neling microscope.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Light absorption layer 3 Light reflection layer 4 Protective layer 5 Pit 6 Deformation part 6 'Deformation part 10 Void part 10' Void part 11 Fine bubble 12 Optical modification part 13 Optical characteristic modification part

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Takashi Ishiguro 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Yuden Co., Ltd. (56) References JP-A-9-138972 (JP, A) JP-A-2 JP-139732 (JP, A) JP-A-58-189851 (JP, A) JP-A-63-259854 (JP, A) JP-A-59-217245 (JP, A) (58) Fields investigated (Int. . ⁶ , DB name) G11B 7/24 G11B 7/00

Claims (5)

(57) [Claims] 1. A light-absorbing layer that absorbs laser light directly on a light-transmitting substrate or through another layer, and reflects the laser light directly on the light-absorbing layer or through another layer. In a recording method for an optical information recording medium in which a pit for reproducing data is formed by irradiating a laser beam with a light reflecting layer, the laser beam is absorbed into the light absorbing layer to generate heat while irradiating the laser beam. Melting, evaporating, sublimating, deforming or denaturing, deforming the layer on the substrate adjacent to the light absorbing layer in the pit portion by laser light irradiation, and decomposing the laser light irradiated portion of the light absorbing layer Forming a pit at a position irradiated with a laser spot. 2. A light-absorbing layer that absorbs laser light directly on a light-transmitting substrate or through another layer, and reflects the laser light directly on the light-absorbing layer or through another layer. In a recording method of an optical information recording medium in which a pit for reproducing data is formed by irradiating a laser beam with a light reflecting layer, the laser beam is absorbed into the light absorbing layer to generate heat while irradiating the laser beam. Melting, evaporating, sublimating, deforming or denaturing, and diffusing or viscous flowing a part of the components constituting the light absorbing layer to a layer adjacent to the same layer by irradiating a laser beam, and passing this to the light absorbing layer. A recording method for an optical information recording medium, comprising: forming a pit at a position irradiated with a laser spot by mixing or partially combining a component of a layer on an adjacent light-transmitting substrate side. 3. A light-absorbing layer that absorbs laser light directly on a light-transmitting substrate or through another layer, and reflects the laser light directly on the light-absorbing layer or through another layer. In a recording method for an optical information recording medium in which a pit for reproducing data is formed by irradiating a laser beam with a light reflecting layer, the laser beam is absorbed into the light absorbing layer to generate heat while irradiating the laser beam. Melting, evaporating, subliming, deforming or denaturing, peeling off the interface between the light absorbing layer and another layer adjacent thereto by irradiating a laser beam, and forming a void there, or forming the light absorbing layer. A recording method for an optical information recording medium, characterized in that bubbles are generated in a layer, and pits are formed at positions irradiated with a laser spot. 4. The light-transmitting layer according to claim 1 , wherein a part of the constituents of the light-absorbing layer diffuses or viscously flows into a layer adjacent to the light-absorbing layer. A recording method for an optical information recording medium, wherein the recording medium is mixed with or partially combined with a component of a layer on the side of a conductive substrate. 5. A Patent paragraph 1 or claim 2, interface with other layers adjacent thereto and the light absorbing layer is peeled off, there? Air gap is formed, or the A recording method for an optical information recording medium, wherein bubbles are generated in the light absorbing layer and remain.