JPH08339573A - Optical recording medium - Google Patents

Abstract

PURPOSE: To obtain an optical recording medium with which recording and reproducing using a laser beam of wavelength λ1 are possible and reproducing using a laser beam of wavelength λ2 is possible. CONSTITUTION: This optical recording medium is constituted by providing the surface of a transparent substrate with at least a light absorption layer contg. a dye to absorb the laser beam directly or via another layer and laminating a light interference layer and a light reflection layer on this light absorption layer. The real number part of the double refractive index of the light absorption layer to the light of the wavelength λ1 selected from among 770 to 830nm, defined as n1, the virtual number part thereof, as k1, the real number part of the double refractive index of the light absorption layer to the light of the wavelength λ2 selected from among 630 to 690nm, defined as n2 and the virtual number part thereof, as k2 are n1>=1.8, 0.04<=k1<=0.15, n2>=1.1, 0.04<=k2<=0.6. In addition, the light interference layer consists of two layers composed of an inorg. compd. and org. compd. and the reflectivity measured through the substrate is ∞65% to the light of the wavelength λ1 and >=15% to the light of the wavelength λ2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly to an optical recording medium satisfying the Orange Book standard which is a standard for recordable compact discs (CD-R) and capable of reproducing at two different wavelengths.

[0002]

2. Description of the Related Art Conventionally, a CD-R (CD-R) has been used as a write-once type optical recording medium satisfying the CD (Compact Disc) standard.
The ECORDABLE) has been actively developed and is already on the market. This CD-R has a structure in which an organic dye recording layer, a metal reflection layer, and a protective layer are laminated on a transparent substrate, and the organic dye recording layer is changed by laser light emitted from the transparent substrate side for information. To record.
The reproduction of this recording can be read by a CD player which is widely used due to the high reflectance and contrast of the metal reflection layer.

The conventional CD-R is stipulated in the so-called Orange Book standard on the assumption that recording and reproducing are performed by using a near infrared semiconductor laser having a wavelength of around 780 nm. By the way, there is an increasing demand for recording large-capacity information represented by digital moving images without increasing the size of the medium. In response to such a demand, a red semiconductor laser of 630 to 690 nm having a wavelength shorter than 780 nm has been developed, and since the beam diameter of the laser light can be narrowed down, high density recording and reproducing are possible. .
However, a player with high density equipped with such a red semiconductor laser can reproduce a read-only medium having a high reflectance of 70% or more, which is formed by forming pits on a substrate at the time of molding and providing an aluminum reflection layer. Although designed, it is naturally desired that a medium such as a conventional CD, CD-ROM or CD-R can be played by the high density player.

Since the conventional CD or CD-ROM medium has the pits formed on the substrate and the aluminum reflection layer, the red semiconductor laser light has a reflectance of 70% or more, which is easy for high density players. It can be played back.
On the other hand, a conventional CD-R medium uses a dye in the recording layer, but since the optical characteristics of the dye have a large wavelength dependence, the CD
-R The reflectance of the medium changes greatly with the wavelength. For example, the conventional CD-R medium has a reflectance of 65% or more for light near 780 nm, but the reflectance for red light selected from 630 to 690 nm is 10% or less, and the degree of modulation is small. When the reflectance is 10% or less, it becomes difficult to detect the signal, and even if it can be detected, the error rate and the jitter increase, and it is not easy to reproduce the signal on a high-density compatible player.

Further, for example, Japanese Patent Application Laid-Open Nos. 3-162728 and 5-67352 propose a medium having a structure in which the optical interference layer is one layer, but it is possible to reproduce at a wavelength shorter than the recording wavelength. No conditions are specified for the CD-R medium, and in fact, such a technology has a reflectance of 15% or more at the wavelength of the red semiconductor laser and a large modulation degree, and has a low error rate and a low jitter. It is not possible to obtain a medium with good deviation.

Further, in Japanese Patent Laid-Open No. 2-87339, t-
A medium in which a butyl-substituted phthalocyanine dye is used as a recording layer and SiO ₂ or silicon resin is provided on the recording layer is disclosed. However, when pit edge recording such as CD is performed on this medium, waveform distortion, error rate, and jitter are large, and deviation is not preferable.

The inventors of the present invention have disclosed in Japanese Patent Application No. 7-65653 a medium using an inorganic compound for an optical interference layer, and Japanese Patent Application No.
No. 7-65654 proposes a medium using a polymer in the optical interference layer. These media satisfy the Orange Book in the same manner as the present invention, and the reflectance for red light selected from 630 to 690 nm is 15% or more, and can be reproduced even by a high-density compatible player. However, when recording the same EFM modulation signal as CD, these media have a narrow margin of recording power depending on the type of writer. That is, in the Orange Book standard, when the optimum recording power is P0, P0 x 0.85-
The standard must be satisfied with a recording power of P0 × 1.15. However, in these media, the deviation deviates from the standard especially when recording with a high recording power. That is, the length of the shortest pit, 3T, and the longest pit, 11T, is out of the standard, and a commercially available CD or CD-ROM
In some cases, it could not be played on the player.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned novel problems, and a structure in which at least a light absorbing layer, a light interference layer consisting of two layers, and a light reflecting layer are laminated on a transparent substrate. By satisfying the Orange Book standard, which is a CD-R standard, recording and reproduction can be performed with light having a wavelength selected from 770 to 830 nm, and 630 to 690 nm.
An object of the present invention is to provide an optical recording medium capable of reproducing a signal with light having a wavelength selected from

[0009]

In order to solve the above-mentioned problems, the present inventors have optimized the optical characteristics of the light-absorbing layer and used a specific phthalocyanine dye, and used a light-absorbing layer and a light-reflecting layer. By providing two suitable optical interference layers in between,
We have completed an optical recording medium that can reproduce signals satisfactorily at wavelengths shorter than the recording wavelength. That is, the gist of the present invention is specified by the following matters. (1) A light absorbing layer containing a dye that absorbs at least a laser beam is provided on a transparent substrate directly or through another layer, and a light interference layer and a light reflecting layer are laminated on the light absorbing layer. Which is an optical recording medium having a light absorption layer of 770 to 830.
The real part of the complex index of refraction for light of wavelength λ1 selected from nm is n1, the imaginary part is k1, and the real part of complex index of refraction for light of wavelength λ2 selected from 630 to 690 nm is n2.
, Where imaginary part is k2, n1 ≧ 1.8, 0.04 ≦
k1 ≤0.15, n2 ≥1.1, 0.04 ≤k2 ≤0.
6 and the light interference layer is composed of two layers of an inorganic compound and an organic compound, and the reflectance measured through the substrate is 65% or more for light of wavelength λ1 and 15% for light of wavelength λ2. The above is an optical recording medium characterized by being recordable and reproducible using laser light of wavelength λ1 and reproducible using laser light of wavelength λ2. (2) The optical recording medium according to (1), wherein the dye used in the light absorbing layer is a phthalocyanine dye represented by Formula (1) or [Chemical Formula 2].

[0010]

[Chemical 2][In the formula (1), M is two hydrogen, or a metal or a metal.
Of the oxides and metal halides of Y₁, Y₂, Y
₃, Y_FourIs oxygen or sulfur, Z₁, Z₂, Z₃, Z_FourIs
Unsubstituted or substituted hydrocarbon group having 4 to 12 carbons
X₁, X₂, X ₃, X_FourRepresents halogen, l₁,
l₂, L₃, L_FourIs 1 or 2, m₁, M₂, M₃, M
_FourRepresents an integer of 0 to 3. ] (3) The light reflection layer is made of gold and is described in (1) or (2).
Optical recording medium mounted. (4) From the substrate surface at the wavelength λ2 of the laser light
Any of (1) to (3) whose reflectance is 20% or more
An optical recording medium described therein. (5) The optical recording medium according to any one of (1) to (4).
In addition, information is recorded and reproduced using laser light of wavelength λ1.
Playback with a laser beam of wavelength λ2.
Characteristic recording / playback method.

[0011]

DESCRIPTION OF THE SPECIFIC STRUCTURE OF THE INVENTION The optical recording medium of the present invention comprises 7
The reflectance from the substrate surface for light having a wavelength selected from 70 to 830 nm is 65% or more, and 630 to 69.
The reflectance from the surface of the substrate for light having a wavelength selected from 0 nm is 15% or more. CDs and CDs currently on the market
-The ROM player is usually mounted with a semiconductor laser having a wavelength of about 780 nm and is made so as to be compatible with a medium having a reflectance of 65% or more.
It can be played on a D-ROM player. on the other hand,
Currently, there is no particular limitation on the reflectance of a medium that can be reproduced by a high-density compatible player equipped with a laser of a wavelength selected from 630 to 690 nm, but from a medium such as a CD recorded with a pit edge (mark length). When a signal is detected, if the reflectance is very small (10% or less), the signal cannot be actually detected and cannot be reproduced. Further, although a high density player is designed to be able to reproduce a read-only medium having a high reflectance of 70% or more, a medium having a reflectance of 70% or more is required.
In order to be able to reproduce both of the media having the reflectance of less than or equal to%, the dynamic range of the reflectance is too wide, and therefore, it is necessary to change the circuit according to the reflectance of the medium. Therefore, the reflectance for light having a wavelength selected from 630 to 690 nm is preferably 15% or more, more preferably 20% or more.

The optical recording medium of the present invention comprises, on a transparent substrate, a light absorbing layer containing at least a dye that absorbs laser light, and a light interference layer consisting of two layers in which an inorganic compound and an organic compound are laminated. A light reflection layer is sequentially laminated. The transparent substrate used in the present invention is preferably a material having a high transparency with a refractive index of about 1.4 to 1.6 with respect to light in order to record and read a signal. Further, it is desirable that the light transmittance is 85% or more and the optical anisotropy is small. For example, a preferable example is a substrate using a thermoplastic resin such as an acrylic resin, a polycarbonate resin, a polyamide resin, a vinyl chloride resin, or a polyolefin resin. Among these, injection-molded resin substrates of acrylic resin, polycarbonate resin, and polyolefin resin are preferable from the viewpoint of mechanical strength of the substrate, easiness of giving a guide groove or reproduction-only signal, and economical efficiency, and particularly polycarbonate is preferable. A resin substrate is more desirable.

The shape of these transparent substrates may be plate-shaped, film-shaped, circular or card-shaped. The surfaces of these substrates may have guide grooves or pits indicating recording positions. Such guide grooves and pits are preferably provided at the time of molding the substrate, but can also be provided by applying an ultraviolet curable resin layer on the substrate, superposing it on a stamper, and performing ultraviolet exposure. When used as a normal CD, the thickness is about 1.2 mm and the diameter is 80 to 130 m.
It has a disk shape of about m and has a hole with a diameter of about 15 mm in the center.

In the present invention, the light absorbing layer contains a dye, and the optical characteristics of the light absorbing layer are important in terms of reflectance, recording sensitivity, modulation degree, etc., and are 770 to 830 nm.
For light having a wavelength λ1 selected from the above, the real part n1 of the complex refractive index of the light absorption layer is 1.8 or more, and the imaginary part k1 is 0.04.
It is preferable that the real part n2 of the complex refractive index for light of wavelength .lambda.2 selected from .about.0.15 and 630 to 690 nm is 1.1 or more and the imaginary part k2 is 0.04 to 0.6. λ1 when n1 is less than 1.8 or when k1 exceeds 0.15
Light reflectance of less than 65%, k1 is 0.0
When it is less than 4, the recording sensitivity for light of λ1 is lowered.
Further, when n2 is less than 1.1 or when k2 exceeds 0.6, the reflectance for the light of .lambda.2 is less than 15%, which is not preferable. There is no particular limitation on the lower limit of k2, but since it is desirable to be able to record with light of λ2, λ
A value less than 0.04 is not preferable from the viewpoint of recording sensitivity to the light of 2.

In the present invention, the dye used in the light-absorbing layer is a dye having a light-absorbing ability with respect to the laser light wavelength λ1, and specifically, it is a phthalocyanine dye, a polymethine dye, a cyanine dye, an azo dye. , Naphthoquinone dyes and the like, but phthalocyanine dyes are preferable from the viewpoint of the durability of the dye, and further, the optical characteristics of the light absorption layer, the recording sensitivity, the degree of modulation, the distortion of the recording waveform, the error rate and the jitter, etc. From the viewpoint of medium characteristics, the following formula (1),
The phthalocyanine dye represented by [Chemical Formula 3] is most preferable.

[0016]

[Chemical 3][In the formula (1), M is two hydrogen, or a metal or a metal.
Of the oxides and metal halides of Y₁, Y₂, Y
₃, Y_FourIs oxygen or sulfur, Z₁, Z₂, Z₃, Z_FourIs
Unsubstituted or substituted hydrocarbon group having 4 to 12 carbons
X₁, X₂, X ₃, X_FourRepresents halogen, l₁,
l₂, L₃, L_FourIs 1 or 2, m₁, M₂, M₃, M
_FourRepresents an integer of 0 to 3. ] The ingredient of M in the phthalocyanine dye represented by the formula (1)
Examples of the body are Cu, Pd, Ni, Mg, Zn, Pb,
Divalent metals such as Cd, metal oxides such as VO, and AlC
Examples thereof include metal halides such as l. On the other hand, replace
Group Z₂, Z₂, Z₃, Z_FourIs an unsubstituted group having 4 to 12 carbon atoms
Or a substituted hydrocarbon group, specifically, a butyl group,
Pentyl group, hexyl group, heptyl group, octyl group,
Nyl group, dodecyl group, cyclohexyl group, dimethylcyclo
Saturated hydrocarbon groups such as lohexyl group, butenyl group, hex
Cenyl group, octenyl group, dodecenyl group, phenyl group,
Methylphenyl group, butylphenyl group, hexylphenyl
And an unsaturated hydrocarbon group such as a ruthel group. These charcoal
The hydrogen halide group may be linear or branched. Also these charcoal
Hydrogenated groups include halogens, amino groups, ether groups and thioethers.
It may be substituted with a ter group. Amino group, ether group
Or even if it is substituted with a thioether group
All carbon numbers are from 4 to 12. X₁, X₂,
X₃, X_FourHalogen represented by is fluorine, salt
Examples thereof include elemental, bromine and iodine.

The above-mentioned substituents X _{1 to} X ₄ and the substituent Y bonded to the benzene ring constituting the phthalocyanine dye.
The substitution position of _{1 to} Y ₄ is not particularly limited, and the type and number of substituents may be different in the four benzene rings in one molecule.

Among the above-mentioned phthalocyanine dyes, l ₁ to l ₄ are preferably ₁ from the viewpoint of recording characteristics such as reflectance and sensitivity, waveform distortion, error rate and jitter. Specific examples of preferable phthalocyanine dyes include, for example, JP-A-3-62
Known phthalocyanine dyes described in JP-A No. 878, JP-A-3-141582, and JP-A-3-215466 are mentioned.

When the light absorbing layer is formed, it can be formed only by the above-mentioned phthalocyanine dye.
Recording characteristics, other organic dyes such as substituted phthalocyanines other than the above-mentioned structure to improve the optical properties, substituted naphthalocyanines, substituted porphyrin dyes, cyanine dyes, dithiol metal complexes, anthraquinone dyes, and the like,
Organic metal complexes such as metallocene, metal complexes of diketone or resins such as nitrocellulose, ethyl cellulose, acrylic resin, polystyrene resin, urethane resin, and various additives such as leveling agents and defoaming agents within the range that does not impair the effects of the present invention. For example, 70% or less, preferably 50%
The following may be used together.

The light absorbing layer is usually prepared by spin coating,
The film can be formed by means of dip coating, spray coating, roll coating, vapor deposition and the like, but the spin coating method is preferable from the viewpoint of easy film formation. A solvent which does not damage the substrate when the dye is formed by spin coating, for example, hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, an aliphatic or alicyclic hydrocarbon solvent such as dimethylcyclohexane,
Ether-based solvents such as diethyl ether, dibutyl ether and diisopropyl ether, alcohol-based solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, allyl alcohol and methyl cellosolve, halogen-based solvents such as carbon tetrachloride and tetrafluoropropanol are preferable. In addition to the above-mentioned solvents, for example, ester-based, ketone-based, aromatic-based or halogen-based solvents may be mixed and used within a range that does not damage the substrate.
From the viewpoint of solubility in these solvents, in the phthalocyanine dye of formula (1), the groups represented by Z ₁ , Z ₂ , Z ₃ and Z ₄ are preferably groups having 6 to 12 carbon atoms. .

In the present invention, the thickness of the light absorbing layer containing the dye is not particularly limited, but is usually 80.
The range of ˜250 nm is desirable. If the film thickness is much smaller than 80 nm, the degree of modulation (signal amplitude) becomes small and C
When the D standard is no longer satisfied and the film thickness is much thicker than 250 nm, the reflectance is lowered and the CD standard is not satisfied, and the reproduction signal characteristics are deteriorated.

In the present invention, the light absorbing layer is formed on the substrate as described above. At this time, the solvent resistance of the substrate is improved between the substrate and the light absorbing layer, and the recording characteristics are improved. An intermediate layer may be provided to improve the reflectance. Examples of the material used for the intermediate layer include substances used for the optical interference layer described below and various known thermosetting or thermoplastic polymers.

The optical interference layer used in the present invention is characterized by laminating an inorganic compound and an organic compound, but the laminating order is not particularly limited, and the inorganic compound may be placed on top. It's good or you can put it down.

The material used for the light interference layer is preferably one having a small imaginary part of the complex refractive index and easy film formation. As a preferable inorganic compound material, for example, silicon,
Oxides and nitrides of aluminum, titanium, thallium, zirconium, scandium and the like, for example, silicon nitride and silicon oxide can be used, and further sulfides of zinc, cadmium and tin can be used. Furthermore, these materials can be mixed and used. As a method for producing the optical interference layer made of these inorganic compounds, a known vacuum film forming method such as a vacuum vapor deposition method, a sputtering method or an ion plating method is used.

Examples of preferable organic compound materials used for the light interference layer include organic dyes such as cyanine-based, azo-based, phthalocyanine-based, and porphyrin-based dyes, and polystyrene, polyvinylpyrrolidone, polyvinyl alcohol, methylcellulose, silicone resin, and the like. Examples include polymers. Also, an organic dye and a polymer can be mixed and used. The light interference layer made of these organic compounds can be formed by a method such as spin coating, dip coating, spray coating, roll coating, or vapor deposition as in the case of the above light absorbing layer. Thus, by forming the light interference layer provided between the reflection layer and the dye layer into two layers of an inorganic compound and an organic compound, the recording power margin is widened and the reproduction stability is improved.

The film thickness of the light interference layer depends on the reflectance of the medium, the degree of modulation,
It is specified within a range where various characteristics such as jitter, error rate, and deviation are not impaired, and varies depending on the refractive index of the light interference layer, but the thickness of both layers is usually 20 to 300 nm in terms of reflectance, Preferably 20-260n
m, further 20 nm to 160 nm, more preferably 40 nm to 140 nm. On the other hand, the thicknesses of the inorganic compound layer and the organic compound layer of the light interference layer are 5 nm to 155 nm and preferably 30 nm to 120 nm, respectively, in terms of deviation.

The material of the light reflecting layer used in the present invention is A which exhibits a high reflectance at the laser light wavelengths λ1 and λ2.
Metals such as u, Ag, Pt, Al and Cu, and alloys of these metals are preferable, and Au is more preferable from the viewpoint of reflectance.
As a method for producing the light reflecting layer, a vacuum film forming method such as a vacuum vapor deposition method, a sputtering method, or an ion plating method is used. In the present invention, the film thickness of the light reflection layer is usually 30.
Is about 300 nm, and more preferably about 50 to 150 nm.

In the present invention, a protective layer may be provided on the reflective layer to protect the recording layer or the reflective layer, a film or a resin substrate may be laminated, or two media of the invention may be laminated. good. Materials used for the protective layer include acrylic resin, polycarbonate resin, ultraviolet curable resin,
Electron beam curing resin, polysiloxane resin, etc. are used,
A resin with excellent impact resistance is selected.

The protective layer is generally obtained by coating a monomer and an oligomer which can be polymerized to form a polymer and then performing a crosslinking reaction. The material is not limited to an organic compound, and may be a mixed component of an organic compound and an inorganic compound, or an inorganic material may be formed by a method such as a sputtering method or a vacuum deposition method.

When it is obtained as an organic polymer by a crosslinking reaction, a reactive acryloyl group in the molecule,
Alternatively, a method in which a small amount of a reaction initiator and a reaction catalyst are added to a mixture of monomers and oligomers of a polymerizable organic compound having one or more epoxy groups, a liquid mixture of these is applied, and the mixture is crosslinked by irradiation with ultraviolet rays or electron beams. But,
It is advantageous in terms of workability.

The protective layer is usually prepared by spin coating, dip coating, spray coating, roll coating,
The film can be formed by a means such as a screen printing method, but a spin coating method or a screen printing method is preferable from the viewpoint of easy film formation. The thickness of the protective layer is generally 0.1.
It is in the range of μm to 100 μm. In the present invention, the thickness of the protective layer is preferably 2 to 30 μm and 3 to
20 μm is more preferable. The optical recording medium of the present invention can be further printed with a label or the like on the protective layer.

As a method for recording information on the optical recording medium of the present invention, for example, while rotating the optical recording medium at a constant linear velocity (preferably 1 to 15 m / sec), the transparent substrate side is moved to the bottom of the guide groove. This is performed by irradiating a laser beam to form a reproducing pit in the light absorbing layer in the guide groove shape and recording a signal. As the signal, for example, E of the CD standard is used.
The method of recording the FM signal is preferable for obtaining the effect of the present invention. The pit means that the organic dye contained in the transparent substrate and / or the light absorbing layer absorbs laser light to generate heat, and melts, evaporates, sublimes, deforms or deteriorates, so that the pit is formed between the transparent substrate and the light absorbing layer. Any change in form such as a convex, wavy, or concave change, a change in the light absorption layer, or a change between the light absorption layer and the light interference layer. say.

The optical recording medium of the present invention has a thickness of 770 to 830 nm.
It is possible to record with a laser beam having a wavelength selected from. Particularly, laser light having a wavelength of about 780 nm is preferable. Further, it is possible to record with light having a wavelength selected from 630 to 690 nm. The laser output at the time of recording varies depending on the rotation speed of the medium, but is usually about 4 to 20 mW. Further, the medium of the present invention has a reflectance of 65% or more for light having a wavelength selected from 770 to 830 nm and a reflectance of light having a wavelength selected from 630 to 690 nm measured by incident light from the substrate side. 15% or more, preferably 20% or more. Therefore, recording / reproduction can be easily performed with a commercially available CD player or CD-ROM player equipped with a laser having a wavelength of about 780 nm. Furthermore, 63
Selected from 0 to 690 nm, for example around 635 nm,
It can be reproduced well even by a high density player equipped with a laser having a wavelength of around 650 nm or around 680 nm.

[0034]

According to the finding of the present inventors, a laser having a wavelength selected from wavelengths 770 to 830 nm is obtained by optimizing the refractive index and the film thickness of the light interference layer for a specific light absorption layer. The reflectance for light is 65% or more, and C
Recording / playback that complies with the D standard is possible, and the wavelength is 630
An optical recording medium (CD-R) that can be favorably reproduced with a laser beam having a wavelength selected from ˜690 nm is realized.

[0035]

EXAMPLES Examples of the present invention will be shown below, but the technical scope of the present invention should not be construed as being limited thereto. Example 1 A 3.5% by weight dimethylcyclohexane solution of Pd.phthalocyanine having one 1-isopropyl-isoamyloxy group at each α-position of each of the four benzene rings constituting phthalocyanine was introduced into a guide groove (width: 0. 4μ
m, depth: 140 nm, pitch: 1.6 μm) polycarbonate resin substrate (diameter 120 mmφ, thickness 1.
2mm disk) and spin coated at 1500rpm.
It dried at 0 degreeC for 2 hours, and formed the light absorption layer with a film thickness of 120 nm. The optical constant of this light absorption layer is 780 nm, the real part of the complex refractive index is 2.0 and the imaginary part is 0.05.
At 35 nm, the real part of the complex refractive index was 1.15 and the imaginary part was 0.36. On this recording layer, a Si ₃ N ₄ film of 35 nm is formed as an interference layer made of an inorganic compound by reactive sputtering using a sputtering device manufactured by Shibaura Seisakusho.
Formed. The refractive index of this thin film measured at 780 nm and 635 nm is 1.83 for both wavelengths.

Further, on the Si ₃ N ₄ film, an azo dye formula (2) having the structure shown below, [Chemical Formula 4] was spin-coated with a tetrafluoropropanol solvent at 2000 rpm, and at 2 ° C. at 70 ° C. The film was dried for a period of time and formed into a film having a thickness of 115 nm to form an interference layer made of an organic compound.

[0037]

[Chemical 4] Next, a 100 nm-thick Au film was formed on the recording layer by using a Balzers sputtering device (CDI-900).
Was sputtered to form a reflective layer. Further, an ultraviolet curable resin SD-17 (manufactured by Dainippon Ink and Chemicals, Inc.) was spin-coated on the reflective layer, and then irradiated with ultraviolet rays to a thickness of 6 μm.
An optical recording medium was produced by forming a protective layer of This optical recording medium was used with a Philips writer (CDD-521) equipped with a 780 nm semiconductor laser head to obtain a linear velocity of 2.8 m / s and E while changing the laser power.
The FM signal was recorded. After recording, a commercially available CD player (Y
AMAHA CDX-1050, laser wavelength 786n
The signal was reproduced using m) and the characteristics were evaluated. The optimum recording power was 9.0 mW. The signals recorded with this optimum recording power and 10.5 mW both satisfy the Orange Book standard in reflectance, modulation, error rate, jitter, and deviation, and the reproduced signals have very good results such as almost no distortion. Obtained.

Next, this medium was recorded at 9.0 mW and 10.5 mW by the writer (CDD-521) using an optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial Co., Ltd. equipped with a 635 nm red semiconductor laser head. The signal was reproduced and evaluated. As a result, the groove reflectance is 29%, the degree of modulation of the shortest pit is large,
There was almost no reproduced waveform distortion, and the jitter, error rate and deviation were also very good.

Comparative Example 1 An optical recording medium similar to that of Example 1 was prepared except that the Si ₃ N ₄ film as an interference layer made of an inorganic compound was not provided. The produced medium was recorded with an EFMS signal with a Philips writer equipped with a 780 nm semiconductor laser head in the same manner as in Example 1, and the above CDX was used.
It was reproduced by -1050 and the above DDU-1000 and evaluated. As a result, the optimum recording power was 9.0 mW. At the optimum recording power, reproduction by CDX-1050 was able to achieve reproduction satisfying the Orange Book standard in reflectance, modulation, error rate, jitter, and deviation. However, when recorded at 10.5 mW, the deviation did not satisfy the standard. DDU-10
At 00, the reflectance was 25%, and at the optimum recording power, the modulation, jitter, error rate and deviation were good, but at the recording power of 10.5 mW, the deviation was poor.

Comparative Example 2 An optical recording medium similar to that of Example 1 was prepared except that the azo dye film as an interference layer made of an organic compound was not provided. The produced medium was recorded and reproduced in the same manner as in Example 1 and evaluated. As a result,
The optimum recording power was 10.0 mW. CDX-
When reproduced at 1050, reflectance, jitter, deviation, etc. satisfied the Orange Book standard at this optimum recording power, but the deviation was out of standard at a recording power of 11.5 mW. With DDU-1000, the reflectance was 21%, and the modulation, jitter, error rate and deviation were good at the optimum recording power, but the deviation was poor at a recording power of 11.5 mW.

[0041] Example 2 replacing the stacking order of the interference layer serving azo dye of interferometric layer serving Si ₃ N ₄ and an organic compound consisting of an inorganic compound used In Example 1 Si ₃
The film thickness of N ₄ is 40 nm, and the film thickness of the azo dye is 110
A medium was prepared and evaluated in the same manner as in Example 1 except that the thickness was changed to nm. Next, recording and reproduction were performed on this medium in the same manner as in Example 1. As a result, the optimum recording power was 9.5 mW. As a result of reproducing with the above CDX-1050, all the characteristics satisfied the Orange Book standard at both the optimum recording power and the recording power of 11.0 mW, and good reproduction could be performed. Next, the reproduction result with DDU-1000 was such that the reflectance was 23%, the waveform distortion was small at both the optimum recording power and the recording power of 11.0 mW, and the modulation factor, jitter, error rate, and deviation were very good. .

Further, signals were reproduced from this medium by a high density player equipped with a 680 nm semiconductor laser. The groove reflectance was 20%, the modulation degree of the shortest pit was 0.6, there was almost no reproduced waveform distortion, and the jitter, error rate, and deviation were very good. Also, good recording was possible with this medium with light of 680 nm. The real number part and the imaginary number part of the complex refractive index of the light absorption layer of this medium for light of 680 nm were 1.20 and 0.49, respectively.

Example 3 Instead of the dye used in Example 1, Ni having one octylthio group at each α-position of four benzene rings constituting phthalocyanine was used.
・ Using a phthalocyanine dye, the above-mentioned Si ₃
A medium was prepared and evaluated in the same manner as in Example 1 except that SiO ₂ was deposited in a thickness of 40 nm instead of N ₄ and polyvinyl alcohol was deposited in a thickness of 35 nm by a spin coating method instead of the azo dye. The optical constant of the light absorption layer is 780 nm, the real part of the complex refractive index is 2.3, and the imaginary part is 0.12.
At 635 nm, the real part of the complex refractive index was 1.2 and the imaginary part was 0.30. Recording and reproduction were performed on this medium in the same manner as in Example 1. As a result, the optimum recording power is 1
It was 0.5 mW. As a result of reproducing with the above CDX-1050, all the characteristics satisfy the Orange Book standard at both the optimum recording power and the recording power of 12.0 mW,
Good reproduction was possible. Further, the reproduction result with the above DDU-1000 shows that the reflectance is 25%, there is almost no waveform distortion at both the optimum recording power and the recording power of 12.0 mW, and the degree of modulation, jitter, error rate, and deviation are extremely high. Was very good.

Example 4 The stacking order of polyvinyl alcohol and SiO ₂ used in Example 3 was exchanged, and polyvinyl alcohol was 100 nm and SiO ₂ was 110 n.
A medium was prepared and evaluated in the same manner as in Example 3 except that m was used. Recording and reproduction were performed on this medium in the same manner as in Example 1. As a result, the optimum recording power was 10.0 mW. When reproduced with the above CDX-1050, results were obtained in which all the characteristics satisfied the Orange Book standard at both the optimum recording power and the recording power of 11.5 mW. Next, above D
When reproduced with DU-1000, the reflectance was 21%, there was almost no waveform distortion at both the optimum recording power and the recording power of 11.5 mW, and the degree of modulation, jitter, error rate and deviation were good.

[0045]

The optical recording medium having a light absorbing layer containing a specific phthalocyanine dye, a light interference layer consisting of two layers of an inorganic compound and an organic compound, and a light reflecting layer on a substrate has a thickness of 770 to 780. By making the reflectance for the light having the wavelength λ1 selected from 830 nm 65% or more and the reflectance for the light having the wavelength λ2 selected 630 to 690 nm of 15% or more, particularly the light interference layer is made of an inorganic compound and an organic compound. By recording with light of λ1 by using two layers of
The recording power margin is widened, and recording and reproduction satisfying the Orange Book can be performed. In addition, there is an effect that the light of λ2 can be reproduced well.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideki Umehara 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (5)

[Claims] 1. A light absorbing layer containing a dye that absorbs at least a laser beam is provided on a transparent substrate directly or through another layer, and a light interference layer and a light reflecting layer are laminated on the light absorbing layer. The optical recording medium having the structure of
The real part of the complex index of refraction for light of wavelength λ1 selected from 830 nm is n1, the imaginary part is k1, and 630 to 690 nm
When the real part and the imaginary part of the complex index of refraction for light of wavelength λ2 selected from are n2 and k2, n1 ≧ 1.8, 0.0
4≤k1 ≤0.15, n2 ≥1.1, 0.04 ≤k2 ≤
0.6, and the optical interference layer is composed of two layers of an inorganic compound and an organic compound, and the reflectance measured through the substrate is 65% or more for light of wavelength λ1 and for light of wavelength λ2. An optical recording medium, which is 15% or more, is recordable and reproducible by using a laser beam having a wavelength λ1, and is reproducible by using a laser beam having a wavelength λ2. 2. The dye used in the light absorbing layer is represented by the formula (1),
A phthalocyanine dye represented by [Chemical Formula 1].
The optical recording medium according to 1. [Chemical 1][In the formula (1), M is two hydrogen, or a metal or a metal.
Of the oxides and metal halides of Y₁, Y₂, Y
₃, Y_FourIs oxygen or sulfur, Z₁, Z₂, Z₃, Z_FourIs
Unsubstituted or substituted hydrocarbon group having 4 to 12 carbons
X₁, X₂, X ₃, X_FourRepresents halogen, l₁,
l₂, L₃, L_FourIs 1 or 2, m₁, M₂, M₃, M
_FourRepresents an integer of 0 to 3. ] 3. The light reflecting layer is made of gold.
The optical recording medium according to 1. 4. The optical recording medium according to claim 1, wherein the reflectance of the laser beam from the substrate surface at a wavelength λ2 is 20% or more. 5. The optical recording medium according to any one of claims 1 to 4, wherein information is recorded and reproduced by using a laser beam of wavelength λ1 and further reproduced by using a laser beam of wavelength λ2. Recording and playback method.