JPH1199747A - Optical-recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with short wave lengths, provide a high sensitivity, and also stabilize a coloring matter film by using a recording layer of which the main component is a styryl-based cyanin coloring matter represented by a specified formula, on a resin substrate. SOLUTION: A recording layer of a resin substrate has a major component of a styryl based cyanin coloring matter represented by a formula (in the formula, R<1> represents an alkyl group or which the number of carbon atoms is 1 through 18, an aryl group or a hydroxyal group, R<2> represents an alkyl group or an aryl group, a negative ion X<-> represents I<-> , Br<-> , or CH3 -C6 H4 -SO3 <-> , Y<1a> and Y<1b> both represent a nitrile group, a hydroxyl group, a carboxyl group, halogen atom, Y<2> represents -NH2 ; -N(R<3> )2 (in the formula, R<3> represents an alkyl group of which the number of carbon atoms is 1 through 7, or an aryl group); -N(R<4> R<5> )2 (in the formula, R<4> and R<5> individually independently represent an alkyl group of which the number of carbon atoms is 1 through 7, or aryl group); an alkyl group having -NH2 , -N(R<3> )2 of which the number of carbon atoms is 1 through 18, an aryl group or an alkoxyl group; a nitrogen composition-containing derivative selected from an acetamide group, and an electron donating group of an alkyl group).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical recording medium for performing high-density writing (recording) and reading (reproduction) with short-wavelength laser light. In particular, using a highly sensitive and highly reliable organic dye thin film whose light reflectivity changes with the wavelength of the laser light, it is possible to reduce the spotlight and record and reproduce information with high density, The present invention relates to a write-once optical recording medium conforming to the DVD standard.

[0002]

2. Description of the Related Art Recordable optical information recording media are extremely widespread. Optical recording has a feature that the recording medium does not wear and deteriorate because the recording medium and the recording / reproducing head are not in contact with each other. By making the spot diameter of the light beam smaller, it is attracting attention as a large-capacity information carrier. Development is underway. In such an optical information recording medium, for example, a laser light beam is focused on a recording layer, converted into thermal energy, and recorded (pits are formed) by changing the properties of the recording film by melting, decomposing, removing, or the like. Reproduction is performed by a change in the amount of reflected light from the portion.

As a recording film, a chalcogenide type metal film typified by tellurium was initially put to practical use. However, it is harmful to the human body, the film formation is a dry method, the production cost is high, and the Due to the increasing necessity for higher density, etc., proposals and reports on media using a recording layer mainly composed of an organic dye instead of a recording layer composed of an inorganic metal thin film represented by tellurium have been made. It has increased. The reason is that the recording layer containing an organic dye as a main component has a lower reflectance than the metal recording layer, but the recording film can be formed into a thin film by a low-cost wet method typified by a spin coating method. It has excellent heat resistance, does not corrode, and has low thermal conductivity compared to metal, so that it can be heated locally without being affected by heat compared to a metal recording film. This is because it has many excellent properties such as formation of recording pits and improvement in sensitivity.

In terms of structure, a so-called air sandwich structure in which an air layer is provided on a recording layer made of a dye film, which has been widely used in the past, or a structure capable of obtaining a reproduction signal conforming to the CD standard, is provided. Many optical information recording media have been proposed (Japanese Patent Publication No. 3-759343, Japanese Patent Laid-Open No. 2-8 / 1990).
No. 7341, JP-A-5-67352 and the like, and Nikkei Electronics, January 23, 1989, NO.
469, 107).

Examples of a medium structure conforming to the CD standard include a light absorbing layer made of an organic dye on a light transmitting resin substrate, a light reflecting layer made of Au or the like directly or through a hard layer,
Further, a resin protective layer formed sequentially is known. That is, since it is not possible to obtain a high reflectance of 65% or more only with the organic dye film, a light absorbing layer made of an organic dye is formed on the translucent resin substrate, and the light absorbing layer is formed thereon directly or through a hard layer. An optical recording disk conforming to the CD standard is manufactured by forming a light reflection layer typified by Au and further forming a resin protective layer thereon.

In this optical recording disk, when a laser beam is irradiated, the organic dye layer absorbs the light, melts or decomposes, softens the substrate, and the dye material and the substrate are mixed at the interface. The recording pit is formed by deformation. In the pit portion of the recording deformation layer formed in this manner, the reflectance changes due to the optical phase difference as in the case of the CD, and reading can be performed. The organic dyes used for these are squarylium dyes (JP-A-56-46221 and JP-A-63-46321).
No. 218398, JP-A-1-178494,
JP-A-5-139047, JP-A-7-44904
Publication), naphthoquinone dyes (JP-A-61-2900)
No. 92, JP-A-62-432, JP-A-63-432
168201, JP-A-5-139047, etc.), azo dyes (JP-A-7-16069, JP-A-7-251567, JP-A-8-99467, etc.), phthalocyanine-based dyes (JP 57-820
No. 94, JP-A-57-82095 and JP-A-7-82095.
JP-156550, JP-A-7-16068,
JP-A-7-52544) and the following general formula (I
I), (Wherein, S ¹ and S ² are each an alkyl group, an aryl group or an alkoxyl group, and W ¹ and W ² are a halogen atom, a hydrogen atom, an alkyl group, an alkoxyl group, an aryl group, an alkoxysulfonyl group, a sulfonyl Cyanine dyes represented by an alkyl group, a cyano group or the like, and Z ¹ and Z ² each represent a substituent such as a sulfur atom, an oxygen atom, a selenium atom or ethylene (JP-A-59-24692) Gazette, JP-A-2-873
No. 41, JP-A-6-320869, JP-A-6-320869
-338059, JP-A-6-199045, JP-A-7-262611, JP-A-62-20
JP 1288, JP-B 7-4981, JP-B 8
Japanese Patent No. 2547033).

Of the above-mentioned dye systems, mainly high sensitivity and high S /
An N ratio and the like can be obtained, and a cyanine-based compound is mainly used in terms of thermal characteristics and thinning. Among them, in order to comply with the CD in particular, in general, a dye having absorption and reflectance around 780 nm to 830 nm from the semiconductor laser wavelength, and a methylene chain q at the center of the molecular structure in the above formula (II)
Is generally used in many cases. However, there is a fatal problem that such a dye recording film cannot cope with the short-wavelength laser of the present purpose.

Further, reproduction deterioration, long-term stability of the dye film, C /
It is said that there are problems with the N ratio, the jitter component, and the like.
The causes are (i) a phenomenon in which the dye itself deteriorates and discolors due to heat accumulation in the recording film portion due to exposure of the reading light for a long time, and (ii) recording in which the reading light discriminates between a pit portion and a non-recording portion. Absorption at the boundary surface of the film, causing a phenomenon that gradually causes melting or thermal deformation of the boundary surface, and a phenomenon in which pit contours are destroyed by similar heat accumulation, and (iii) when the dye is photo-excited In addition, oxidative degradation of the dye due to singlet oxygen caused by energy transfer from the dye to oxygen present in the atmosphere (fading of the dye),
(Iv) As a deterioration phenomenon during long-term storage, changes in the transmittance of the dye due to natural light and oxidation of the cyanine dye and the like
It is conceivable that the association and aggregation of the dyes due to moisture and the like may cause a change in transmittance and the generation of noise. In order to solve this problem, various proposals have been made conventionally (for example, Japanese Patent Application Laid-Open No. 62-201288,
JP-A-62-201289, JP-A-57-665
No. 41, JP-A-59-124894, JP-A-59-203247, and JP-A-62-133173.
JP, JP-A-63-198096, JP-A-sho-59
JP-A-21339, JP-A-57-11090,
JP-A-60-44389, JP-A-60-7129
No. 6, JP-A-63-1594, JP-A-57-157.
No. 11090, JP-A-5-38879, JP-A-7-262611, JP-B-7-4981, etc.). However, the reality is that a sufficient solution has not yet been reached.

Further, an optical recording medium having a high recording density conforming to the DVD-ROM standard has been developed. This makes the wavelength of the semiconductor laser shorter than that of the current CD by 60.
In this method, the recording density is increased by setting the wavelength to about 0 to 680 nm, shortening the wavelength of light using an SHG element or the like, and narrowing the objective lens to the laser diffraction limit to reduce the beam spot diameter.

In order to develop such a dye material for DVD-ROM, attempts have been made to improve cyanine dyes for CD represented by the general formula (II), and cyanine dyes for short wavelength have been proposed. (For example, JP-A-5-38879, JP-A-6-40162, JP-A-6-320)
869, JP-A-6-186530, JP-A-6-199045, JP-A-7-262611, JP-A-8-306074, Japanese Patent Publication No. 1-217
No. 98, Japanese Patent Publication No. 7-4981 and the like).

[0011]

However, the sensitivity of the recording layer corresponding to the target wavelength and the stability (reliability) of the film cannot be obtained, and when the density is increased, the thermal interference between adjacent pits occurs. However, many problems have not been solved, such as an increase in the jitter component contained in the reproduced signal.

The present invention has been made in view of the above points, and has as its object to provide a short wavelength semiconductor laser (wavelength 500 to 700 nm).
By finding an organic dye thin film and medium composition with good optical properties, chemical, photochemical, physical and thermal stability that can respond to m), high sensitivity and stability of the dye film as characteristics of optical recording media Excellent in high density recording, especially C / N
An object of the present invention is to provide an optical recording medium compliant with the DVD standard, which has a high ratio and can reduce a jitter component included in a reproduction signal.

[0013]

Means for Solving the Problems The present inventor has conducted intensive studies on various dyes in order to solve the above-mentioned problems. As a result, an optical recording system comprising a recording layer containing a specific still-based cyanine dye as a main component was obtained. The medium is short wavelength (500-700n)
m), it is highly sensitive, has long-term reliability with reduced reproduction degradation, and has reduced thermal interference and heat accumulation between pits at high densification.
It has been found that the N ratio can be improved, the jitter component can be reduced, and that the present invention can be applied to DVD, and the present invention has been completed.

That is, the present invention is as follows. (1) In an optical recording medium in which at least a recording layer and a metal reflection layer are laminated on a surface of a resin substrate having a groove and transmitting laser light, the recording layer has the following general formula ( I), (Wherein, R ¹ is a substituent having an unsaturated bond group having 3 to 18 carbon atoms, R ² is an alkyl group or an aryl group, an anion X ⁻ is I ⁻ , Br ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₄ ^-, S
bF ₄ ⁻ , CH ₃ SO ₄ ^— or CH ₃ —C ₆ H ₄ —SO
_{3 ^-,} Y ^1a and Y ^1b are mainly composed of styryl cyanine dyes in which one electron withdrawing group or one both the other is a hydrogen atom with an electron withdrawing group, represented by Y ² represents an electron-donating group) An optical recording medium comprising an organic thin film corresponding to a short wavelength laser.

(2) In the above optical recording medium, both Y ^1a and Y ^1b are nitro, hydroxyl, carboxyl, carbonyl, alkoxy, cyano, alkoxycyano, halogen, or any one of these terminals. Or one of them is the electron-withdrawing group and the other is a hydrogen atom, and Y ² is -NH ₂ ;-
N (R ³ ) ₂ (wherein R ³ is an alkyl group or an aryl group having 1 to 7 carbon atoms); —N (R ⁴ R ⁵ ) ₂ (wherein R ⁴ and R ⁵ are each independently a carbon atom number 1-7 alkyl group or an aryl group); the terminal _{^{-NH 2, -N (R 3)}} 2 ( wherein, ^{R 3} are the same as those described above) or -N ^(R 4 R
⁵ ) ₂ wherein R ⁴ and R ⁵ are the same as defined above, having 1 to 18 carbon atoms, an alkyl group, an aryl group, an arylalkenyl group, an arylazo group or an alkoxyl group; a hydrazinocarbonyl group; An optical recording medium which is a nitrogen-containing compound derivative selected from the group consisting of acetamido groups and an electron donating group of an alkyl group.

(3) The optical recording medium as described above, wherein the recording layer is an organic thin film composed of a composite system containing two or more styryl cyanine dyes represented by the general formula (I).

(4) The optical recording medium, wherein the recording layer contains 1% or more of an oxygen quencher.

(5) In the optical recording medium, Al, Au, A having a melting point higher than that of the recording layer and having a reflectivity of 55% or more with respect to the wavelength of the laser light on the recording layer.
This is an optical recording medium in which a metal reflection layer of a metal thin film made of an alloy or an alloy selected from the group consisting of g, Cu, Ni, Ti and a chalcogenide-based metal is laminated.

(6) The optical recording medium, wherein a metal reflective layer and a protective layer are sequentially laminated on the recording layer.

(7) In the optical recording medium, a recording layer and a metal reflection layer are sequentially laminated on the grooved substrate,
The optical recording medium is obtained by laminating a one-sided substrate on which a protective layer is further laminated and a non-groove substrate with an adhesive.

(8) In the above optical recording medium, a double-sided type obtained by sequentially laminating a recording layer and a metal reflective layer on a substrate and further laminating a protective layer on each other with an adhesive via the protective layer. Optical recording medium.

(9) In the optical recording medium, grooves are formed on both sides of the substrate at the time of molding, and a recording layer, a metal reflective layer, and a protective layer are sequentially laminated on both sides of the substrate. Optical recording medium.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific configuration of the present invention will be described in detail with reference to the drawings. 1 to 4 show a configuration example of the optical recording medium of the present invention. The illustrated substrate 1 has a disk shape, and tracking pre-pits or pre-grooves are formed concentrically or spirally on one surface of the substrate 1 shown in FIGS. The substrate 1 having such pre-pits or pre-grooves is made of an injection-molded resin from the viewpoint of productivity and the like, and is preferably a semiconductor laser beam of recording light and reproduction light (about 500 to 700 nm), particularly 600 to 680 nm. Is formed of a substantially transparent resin (having a laser light transmittance of 85% or more). The thickness of the substrate 1 is about 1.0 to 1.5 mm in the configuration example shown in FIG. 1, and is about 0.5 to 0.65 mm in the types shown in FIGS.

In the configuration example shown in FIG. 4, pre-pits or pre-grooves are simultaneously formed on both surfaces of the substrate 1, and the thickness of the substrate 1 is about 1.0 to 1.5 mm.

The diameter of the substrate 1 shown in FIGS.
It is about 0 to 120 mm. Further, the resin constituting the substrate 1 is not particularly limited, but from the viewpoint of moldability and light transmittance, polycarbonate resin, polyacryl resin, polyester resin, amorphous olefin resin, TPX,
The main component is a thermoplastic resin such as Arton resin.

The track pitch of the substrate 1 is 0.7 to 1.6.
μm. Further, the depth of the groove is used for tracking control, information holding, and the like according to the phase of the laser beam. The depth of the groove is about 50 to 230 nm, preferably about 70 to 200 nm. If the groove is too shallow, the deformation rate of the groove bottom surface and the influence of the deformation on the metal reflection film are likely to increase, the distortion of the reproduced signal is likely to occur, the C / N ratio tends to decrease, and the jitter tends to increase. It causes the size to become smaller. On the other hand, if the groove is too deep, the amount of deformation of the groove bottom surface of the recording mark portion becomes unstable, and the jitter increases. Thereby, the wavelength dependence of the reproduction signal and the tracking signal increases. Therefore, the depth of the groove is important with respect to the wavelength of the semiconductor laser light at the time of high-density recording, and it is necessary to optimize the depth, shape, and the like according to the characteristics and film forming properties of the organic thin film of the recording layer 2. In addition, the material structure and composition of the recording layer 2 greatly affect the groove.

The recording layer 2 formed on the substrates 1 and 1 'is an organic thin film containing a styryl cyanine dye represented by the general formula (I) as a main component. The styryl-based cyanine dyes of the present invention all have 5
It has absorption / reflection wavelengths in the range of 00 to 700 nm, and has sufficient sensitivity and reflectance for the target laser wavelength (600 to 680 nm).

In particular, the substituent R ¹ of the styryl cyanine dye represented by the general formula (I) has 3 to 18 carbon atoms.
Preferable is a substituent having an unsaturated bond group at the 3- to 9-positions. Ethynyl, butenyl, and the like. Such a group affects solubility, in particular, the compatibility between the film forming property and the surface of the substrate becomes very good, and the stability is improved.

In addition to introducing an unsaturated bond group into R ¹ , both Y ^1a and Y ^1b are electron-withdrawing groups or one of them is an electron-withdrawing group, and the other is a hydrogen atom. , Hydroxyl group, carboxyl group,
Either a carbonyl group, an alkoxy group, a cyano group, an alkoxycyano group, a halogen atom, or an electron-withdrawing group having any one of them at the terminal, or one of them is the electron-withdrawing group and the other is a hydrogen atom. Y ² is an electron donating group, preferably —NH ₂ ; —N (R ³ ) ₂ (wherein,
R ³ is an alkyl or aryl group having 1 to 7 carbon atoms);
N (R ⁴ R ⁵ ) ₂ (wherein R ⁴ and R ⁵ are each independently an alkyl group or an aryl group having 1 to 7 carbon atoms); —NH ₂ , —N (R ³ ) _{2 at the} terminal Wherein R ³ is the same as described above) or —N (R ⁴ R ⁵ ) ₂ (wherein R ⁴ and R ⁵ are the same as defined above), and an alkyl group having 1 to 18 carbon atoms; A nitrogen-containing compound derivative selected from the group consisting of an aryl group, an arylalkenyl group, an arylazo group or an alkoxyl group; a hydrazinocarbonyl group; and an acetamido group; and an electron donating group of an alkyl group. By introducing these substituents, for example, a spectrogram of a styryl-based cyanine dye represented by the following formula (I-2) becomes excellent in optical characteristics as shown in FIG. Therefore, a high C / N ratio is obtained from the viewpoint that a high sensitivity, a high S / N ratio, and a uniform thin film are easily obtained. In addition, by forming the styryl cyanine dye according to the present invention into a thin film by complexing or the like, aggregation and association of the dye can be suppressed. High sensitivity, high S /
An N recording medium and a high C / N ratio can be obtained, and an optical recording medium having excellent uniform film formation stability and reliability can be obtained.

The styryl cyanine dye according to the present invention can be prepared by a known synthesis method (for example, US Pat. No. 2,734,90).
No. 0, U.S. Pat. No. 2,112,2139, U.S. Pat. No. 2,887,479), and specific examples are shown below.

[0031]

[0032]

[0033]

[0034]

The styryl cyanine dye according to the present invention may be used alone, but by combining two or more kinds,
In addition to being able to adjust the spectrum, for example, the absorption and reflectance of laser light, the stability of the film in an amorphous state during thinning can be obtained. From this function, high sensitivity, suppression of jitter components, and generation of noise Can be prevented, and the long-term storage property is improved.

The recording layer 2 may contain an oxygen quencher (light stabilizer) in an amount of 1% or more, preferably 3 to 20%, together with such a dye. If the content of the oxygen quencher in the recording layer is too large, the quencher may cause bleeding or the like, which may cause noise. This quencher captures radicals generated by the degradation of the styryl cyanine dye due to ultraviolet light, laser light, or the like, and stops the chain reaction. Thereby, light stability can be improved, and in particular, decolorization due to reproduction light can be prevented. As a result, the recording layer according to the present invention can achieve long-term storage properties, can suppress the flow of the film due to heat generated by light, and can suppress the generation of noise and the increase in jitter.

The oxygen quencher used together with the styryl-based cyanine dye according to the present invention can be used alone or in combination, and is not particularly limited, but specific examples include the following commonly used ones.

Metal complex system Q1: bis (4-tetra-butyl-1,2-dithiophenolate) M-tetra-n-butylammonium (M is Cu, Co, Ni, Fe, etc.) Sumitomo Seika Co., Ltd. BBT series Q2: bis [4- (diethylamino) -α, β-stilbenedithiolate] nickel NKX-114 Q3: bis [3-methoxy-4- (2-) (Methoxy ethoxy) -2′-chloro-α, β-stilbene dithiolate] Nickel NKX-1199 Q4: 1,2-benzenedithiol nickel complex manufactured by Japan Photographic Pigment Research Institute Mitsui Toatsu Chemicals, Inc. Company PA-1006 etc.

Amine / ammonium salt system Q5: Bisiminium salt IRG-03 Q6 manufactured by Nippon Kayaku Co., Ltd. N, N, N ', N "-tetrakis (p-dibutylaminophenyl) p-phenylenediamine Teikoku Chemical ( NIR-AM1 Q7: 4-nitroso-4 '-(dimethylamino) diphenylamine NKX-1549 manufactured by Japan Photographic Dye Laboratories

The oxygen quencher is not particularly limited to these specific examples, and may be added alone or in combination.

The recording layer 2 containing the styryl cyanine dye according to the present invention as a main component is laminated on the surfaces of the substrates 1 and 1 'as shown in FIGS. Such a recording layer agent, as a coating solvent that does not attack the substrate, for example, methyl cellosolve, ethyl cellosolve, methanol, ethanol, isopropanol, diacetone alcohol, dimethylformamide, cyclohexanone, acetylacetone, tetrafluoropropanol, dichloroethane, dioxane and the like alone Or, by sufficiently dissolving the dye using a mixed solution, generally by a common means such as spin coating,
Films are formed on the molded substrates 1 and 1 'on which the grooves are formed.

The thickness of the recording layer 2 is about 50 to 500 nm.
And preferably about 50 to 300 nm.
If the thickness is less than 50 nm, recording sensitivity and reflectivity are insufficient, and ideal recording cannot be performed. On the other hand, if this thickness is 50
If it exceeds 0 nm, a tracking signal may not be obtained or pits may overlap. As a result, the jitter increases, the waveform distortion of the reproduced signal easily occurs, and the crosstalk may increase. The thickness of the recording layer 2 can be adjusted in consideration of film forming conditions, dye concentration, and groove shape.

The metal reflection layer (light reflection film) 3 provided on the recording film 2 has a higher melting point than that of the recording layer 2 according to the present invention, and has a reflectance of 55% or more, preferably 60%, with respect to the laser beam. %, Al, Au, Ag, Cu, Ni, T
a metal thin film made of an alloy or an alloy selected from the group consisting of i and a chalcogenide-based metal, having a thickness of 30 to 15
0 nm, preferably about 50 to 100 nm. This metal reflection layer 3 is laminated by sputtering, vacuum deposition, ion plating or the like.

As shown in FIGS. 1 to 4, the protective film 4 provided on the metal reflective layer 3 is generally made of a photocurable (ultraviolet curable resin or visible curable resin) by spin coating, spray coating, or gravure. After being applied by a coating method or the like, it is formed by irradiating ultraviolet light or visible light to cure the coating film. Further, an epoxy resin, an acrylic resin, a silicone resin, or the like can be formed by a wet method. Further, an inorganic film such as an SiOx layer may be formed by sputtering, vapor deposition, or the like, and further, a polymer film obtained by polymerizing a resin such as parylene, polyamide, or polyimide by vapor deposition, plasma, or the like may be used. Further, it may be in the form of a sheet. The thickness of the protective film 4 is 0.5 to 50 μm.
The layer may be formed to a thickness of the order.

The double-sided bonded medium shown in FIGS. 2 and 3 is a high-density optical recording medium that can be double-sided recorded / reproduced by laminating with an adhesive or an adhesive tape such as a hot-melt type or an ultraviolet / visible ray curable type. Can be obtained.

The optical recording medium of the present invention has a structure in which a specific recording layer containing a styryl-based cyanine dye having a specific structure as a main component is provided on a substrate. An optical recording medium having high reflectivity, excellent recording characteristics, excellent reproduction stability, excellent long-term storability, and high reliability is achieved, and a DVD-compliant optical recording medium is provided.

[0047]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the following examples, a polycarbonate substrate having a thickness of 6 mm and a groove track pitch of 0.75 μm was used.

Example 1 A quencher (the above-mentioned Q3 and the above-mentioned Q7 were mixed at a weight ratio of 2: 1) to the styryl cyanine dye represented by the formula (I-2) was adjusted to 10% by weight. And mixed with a mixed solvent solution (ethyl cellosolve / ethanol / diacetone alcohol = 5: 2: 3 weight ratio) to prepare a recording layer material. The obtained recording layer agent is sufficiently dissolved at a concentration of 5% by weight using ultrasonic waves, filtered through a filter, and then applied on the substrate by spin coating to form a uniform layer having a thickness of about 60 nm. The obtained recording layer was obtained. Subsequently, a metal reflective layer was formed as a 60 nm thick Al-Ti alloy thin film by a sputtering method. Further, as a protective film, a polyfunctional epoxy acrylate UV curable paint was applied by a spin coat method and cured. The film thickness at that time was about 6 μm. A single-plate recording medium was obtained by the method described above. In order to obtain a double-sided optical recording medium, a desired double-sided optical recording medium was obtained by using a UV-curable adhesive for the adhesive layer and bonding the protective layers to each other by low-temperature pressure bonding.

Example 2 As styryl cyanine dyes, each of the above-mentioned formulas (I-2)
And the same quencher as in Example 1 was added to a system obtained by combining the compound represented by Formula (I-1) and the compound represented by (I-1) at a weight ratio of 2: 1. I got the medium.

Example 3 As styryl cyanine dyes, each of the above-mentioned formulas (I-4)
And a quencher (a mixture of the Cu complex of Q1 and the Q7 at a weight ratio of 2: 1) was used in a system in which the compound represented by the formula (I-10) was compounded at a weight ratio of 2: 1. Example 1
A desired optical recording medium was obtained by the same means and configuration as described above.

Example 4 As styryl-based cyanine dyes, each of the above-mentioned formulas (I-1) was used.
The same quencher as in Example 1 was added to a system in which the compounds represented by 5) and (I-1) were combined at a weight ratio of 1: 1.
A desired optical recording medium was obtained by the same means and configuration as in Example 1.

Comparative Example 1 The following structural formula was used as a laser absorbing dye: Using the dye DY1 (NK-4288, manufactured by Japan Photosensitive Dye Laboratories), using the same quencher as in Example 1, and using the same means and configuration as in Example 1. An optical recording medium was obtained.

Comparative Example 2 The following structural formula was used as a laser absorbing dye: Using the dye DY2 (NK-383 manufactured by Japan Photographic Dye Laboratories Inc.), using the same quencher as in Example 1, and using the same means and configuration as in Example 1. An optical recording medium was obtained.

Comparative Example 3 As a laser absorbing dye, the dye DY2 having the above structural formula and the following structural formula: A quencher similar to that of Example 1 was used in a system in which the dye DY3 (NK-1977, manufactured by Japan Photosensitive Dye Laboratories, Inc.) represented by A desired optical recording medium was obtained by the same means and configuration as described above.

Comparative Example 4 The same quencher as in Example 1 was used as a laser absorbing dye in a system in which the dye DY2 of the structural formula and the dye DY1 of the structural formula were combined at a weight ratio of 1: 1. A desired optical recording medium was obtained by the same means and configuration as in Example 1.

In the above Examples and Comparative Examples, the characteristics of the optical recording medium, that is, the reflectance and the reproduction signal characteristics (C / N,
Era rate) was evaluated. The reproduction signal characteristics are as follows. A semiconductor laser having an oscillation wavelength of 635 nm is condensed at a disc linear velocity of 3.3 m / s at a numerical aperture (NA) of an objective lens of 0.60, recorded at recording Pw, and evaluated using an evaluator. evaluated. In addition, initial characteristics and accelerated light resistance after long-time reproduction (1 × 10 ⁴ times) and high temperature and high humidity (80 ° C., 80%, 24 hours) were tested and evaluated.

As a result, Comparative Example 1 could not be evaluated because the wavelength was different. However, the other media had initial characteristics with a reflectance of 55% or more, a C / N ratio of 52 dB or more, and an error rate of 1 × 10 ⁻⁵ or less. In Examples 1 to 4, particularly, the jitter was about 15%, whereas in Comparative Examples 1 and 2, all were more than 20%. The results of the measurement after the durability test are shown in Table 1 below.

[0058]

[Table 1]

[0059]

The optical recording medium of the present invention has a structure in which a specific recording layer mainly containing a styryl-based cyanine dye having a specific structure is provided on a substrate.
m, with sufficient sensitivity and reflectivity,
It is an optical recording medium that has excellent long-term storage characteristics and reliability, achieves high-density recording by reducing jitter components, and conforms to the DVD standard.

[Brief description of the drawings]

FIG. 1 is a conceptual sectional view of an example optical recording medium of the present invention.

FIG. 2 is a conceptual sectional view of another example of the optical recording medium of the present invention.

FIG. 3 is a conceptual sectional view of still another example of the optical recording medium of the present invention.

FIG. 4 is a conceptual sectional view of an optical recording medium according to still another example of the present invention.

FIG. 5 is a spectrogram of a styryl-based cyanine dye represented by the formula (I-2).

[Explanation of symbols]

 Reference Signs List 1 substrate 1 'groove-free substrate 2 recording layer (organic thin film) 3 metal reflection layer (light reflection film) 4 protective film 6 recording deformation layer pit

Claims (9)

[Claims] 1. An optical recording medium comprising a groove and formed on a surface of a resin substrate that is transparent to a laser beam and at least a recording layer and a metal reflection layer are laminated. Formula (I), (Wherein, R ¹ is a substituent having an unsaturated bond group having 3 to 18 carbon atoms, R ² is an alkyl group or an aryl group, an anion X ⁻ is I ⁻ , Br ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₄ ^-, S
bF ₄ ⁻ , CH ₃ SO ₄ ^— or CH ₃ —C ₆ H ₄ —SO
_{3 ^-,} Y ^1a and Y ^1b are mainly composed of styryl cyanine dyes in which one electron withdrawing group or one both the other is a hydrogen atom with an electron withdrawing group, represented by Y ² represents an electron-donating group) An optical recording medium comprising an organic thin film corresponding to a short wavelength laser. 2. Y ^1a and Y ^1b are each a nitro group, a hydroxyl group, a carboxyl group, a carbonyl group, an alkoxy group, a cyano group, an alkoxycyano group, a halogen atom or an electron-withdrawing group having any of these at the terminal; Alternatively, one of them is the electron-withdrawing group and the other is a hydrogen atom, Y ² is —NH ₂ ; —N (R ³ ) ₂ (where R ³ is an alkyl group or an aryl group having 1 to 7 carbon atoms); −N (R
⁴ R ⁵ ) ₂ (wherein R ⁴ and R ⁵ are each independently an alkyl group or an aryl group having 1 to 7 carbon atoms);
H ₂ , —N (R ³ ) ₂ (wherein R ³ is as defined above) or —N (R ⁴ R ⁵ ) ₂ (where R ⁴ and R
⁵ is the same as described above) and having 1 to 18 carbon atoms
2. A nitrogen-containing compound derivative selected from the group consisting of an alkyl group, an aryl group, an arylalkenyl group, an arylazo group or an alkoxyl group; a hydrazinocarbonyl group; and an acetamido group; and an electron donating group of the alkyl group. Optical recording medium. 3. The optical recording medium according to claim 1, wherein the recording layer is an organic thin film composed of a composite system containing two or more styryl cyanine dyes represented by the general formula (I). 4. The optical recording medium according to claim 1, wherein the recording layer contains 1% or more of an oxygen quencher. 5. An Al, Au, Ag, Cu, Ni, Ti and chalcogenide-based metal having a higher melting point than the recording layer and having a reflectance of 55% or more with respect to the wavelength of the laser light on the recording layer. The optical recording medium according to any one of claims 1 to 4, wherein a metal reflection layer of a metal thin film made of an alloy or an alloy selected from the group consisting of: 6. An optical recording medium according to claim 1, wherein a metal reflective layer and a protective layer are sequentially laminated on the recording layer. 7. A one-sided substrate in which a recording layer and a metal reflective layer are sequentially laminated on a grooved substrate, and a protective layer is further laminated, and a non-groove substrate is bonded with an adhesive. The optical recording medium according to any one of claims 1 to 5, wherein 8. The double-sided type according to claim 1, wherein a recording layer and a metal reflective layer are sequentially laminated on a substrate, and a single-sided type in which a protective layer is further laminated is bonded with an adhesive via a protective layer. An optical recording medium according to any one of the preceding claims. 9. A double-sided type wherein grooves are formed on both sides of a substrate during molding, and a recording layer, a metal reflective layer, and a protective layer are sequentially laminated on both sides of the substrate. The optical recording medium according to any one of claims 1 to 5, wherein