JPH0732736A - Recording film material for optical recording medium and optical recording medium using the same - Google Patents

Abstract

PURPOSE:To enhance the humidity resistance of a phthalocyanine dye by using a specific phthalocyanine compd. as a recording film material used in an optical recording medium performing the recording and regeneration of data due to laser beam. CONSTITUTION:In a write-once optical recording medium consisting of a transparent substrate, a recording film, a reflecting film and a protective film and performing recording and regeneration due to laser beam, the recording film is formed from a phthalocyanine compd. represented by formula [wherein M is Si(OH)2, Ge(OH)2, Al (OH), Ga(OH) or In(OH), R1 and R2 are a hydrogen atom, an alkyl group or an aryl group, R3 is a metal or an amino compd., m and n are an integer of 1-4, R3 of a substituent -SO3<-+>R3 is a metal such as Li, Na or K and butylamine or oleylamine is designated as the amino compd.].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention requires a recording film material for an optical recording medium used in an optical recording medium for recording and reproducing information by a laser beam, and more specifically, high speed and high precision recording is required. The present invention relates to a write-once optical disc compatible with a laser disc (LD).

[0002]

2. Description of the Related Art Conventionally, there are various media for recording information by using a laser beam. One of them is a CD composed of a transparent substrate / recording film / reflection film / protective film. Alternatively, there is a write-once optical disc corresponding to a CD-ROM. Organic dyes such as cyanine dyes and phthalocyanine dyes have been proposed as recording film materials for this medium, and have reached the level of practical use. The recording principle of these R-CDs is
In both cases, digital recording is performed by forming pits due to a shape change associated with the conversion of the irradiation laser light into heat energy. However, it is difficult to control the pit shape because this shape change is due to severe chemical changes such as melting and decomposition.
Distortion and asymmetry are inevitable. Therefore, it is difficult to apply it to a recording medium which requires accuracy higher than R-CD because it causes variations in pit length (jitter) and spread of pit width (crosstalk). Also,
Recording with shape change requires high-power laser irradiation, which makes it difficult to support high-speed recording. As a recording film material that can solve these problems, Japanese Patent Publication No. 3-7
8074 and phthalocyanine dyes proposed in JP-A-4-74691. This phthalocyanine dye has a characteristic that the transmittance of the wavelength of the reproducing laser light changes without being changed in shape by the irradiation of the recording laser, and is a material that can solve the above pit accuracy and recording sensitivity.

[0003]

However, these dyes are synthesized by reacting an amino compound after chlorsulfonation. However, since the chlorosulfonate is not very stable under normal conditions, a phthalocyanine skeleton is formed at the time of synthesis. There is a possibility that -SO3H may remain, and there is a risk that the moisture resistance will deteriorate in practice.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have made residual --SO3H into a salt with a metal or a hydrophobic amino compound in order to improve the moisture resistance of the phthalocyanine dye. By using a recording material, the above problems were solved and the present invention was developed.

That is, the first invention is a recording film material for an optical recording medium, which comprises a phthalocyanine compound represented by the general formula [1]. General formula [1]

[0006]

[Chemical 2]

[In the formula, M is Si (OH) ₂ , Ge (O)
H) ₂ , Al (OH), Ga (OH), In (OH). R
1 and R2 each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent. R3 represents a metal or an amino compound. m and n each independently represent an integer of 1 to 4. Further, the second invention is a write-once type optical recording medium comprising a transparent substrate / recording film / reflection film / protective film, and recording / reproducing with a laser beam, the recording film being represented by the general formula [1]. 1 selected from phthalocyanine compounds
It is a write-once type optical recording medium characterized by comprising one or more phthalocyanine compounds.

The substituent --SO2N-(R) introduced into the phthalocyanine compound represented by the general formula [1] of the present invention.
1) R1 and R2 of (R2) will be described in more detail. Examples of the alkyl group which may have a substituent include a methyl group, an ethyl group, a tert-butyl group, an oleyl group,
Stearyl group, trichloromethyl group, pentafluoroethyl group, 2-methoxyethyl group, N, N-dimethylaminopropyl group, N, N-diethylaminopropyl group,
N, N-dibutylaminopropyl group, 2 (N-piperazino) ethyl group, cyclohexyl group, cyclobutyl group, diethylene glycol monoethyl group, and an aryl group which may have a substituent include a phenyl group, a chlorophenyl group and a toluyl group. Examples thereof include, but are not limited to, naphthyl group, anthryl group, dimethylaminophenyl group, diethylaminophenyl group and hydroxyphenyl group.

Substituent introduced into the phthalocyanine compound represented by the general formula [1] of the present invention: R of --SO3- ⁺ R3
To explain 3 in more detail, as metals,
Li, Na, K, Mg, Ca, Ba, Sr, etc., and as the amino compound, butylamine, oleylamine, stearylamine, pentafluoroethylamine, pyridine, pentafluoropyridine, aniline, p-nitroaniline, anisidine, phenylenediamine, etc. However, the present invention is not limited to this. The phthalocyanine compound represented by the general formula [1] of the present invention is synthesized by the following method. First, a compound synthesized by the method described in JP-B-3-78074 is dissolved or reslurried in water, an aqueous acetic acid solution, or an organic solvent, and then a metal salt or an amino compound is added in a large excess and stirred with heating. After cooling
The desired phthalocyanine compound of the general formula [1] is obtained by filtration and washing.

Typical examples of the phthalocyanine compound represented by the general formula [1] used in the present invention include the phthalocyanine compounds (1) to (10) shown below, but are not limited thereto. is not. Further, these phthalocyanine compounds may be a mixture of isomers having different substitution positions of the substituents on the phthalocyanine ring, but there is no problem in using them as the recording layer of the present invention.

Phthalocyanine compound (1)

[Chemical 3]

Phthalocyanine compound (2)

[Chemical 4]

Phthalocyanine compound (3)

[Chemical 5]

Phthalocyanine compound (4)

[Chemical 6]

Phthalocyanine compound (5)

[Chemical 7]

Phthalocyanine compound (6)

[Chemical 8]

Phthalocyanine compound (7)

[Chemical 9]

Phthalocyanine compound (8)

[Chemical 10]

Phthalocyanine compound (9)

[Chemical 11]

In the recording layer using the phthalocyanine compound represented by the general formula [1] in the present invention, the stability such as light resistance and environment resistance of the recording layer is further improved in the repeated reproduction. You may add additives, such as an oxygen quencher and an ultraviolet absorber. The recording layer can be formed by a dry process such as a vacuum deposition method or a sputtering method, but a wet process such as a spin coating method, a dipping method, a spray method, a roll coating method or an LB (Angmuir) method. (Blodget) method is also possible. The phthalocyanine-based compound of the present invention is a general-purpose organic solvent, for example, alcohol-based,
It dissolves in ketone, cellosolve, hydrocarbon, halogenated hydrocarbon, chlorofluorocarbon, etc. at a concentration of about 10 to 100 mg / ml, so a film is formed by a spin coating method from the viewpoint of productivity and uniformity of recording layer. Is most preferred. When forming a film by such a so-called coating method, a polymer binder may be added if necessary.

Acrylic resin as the polymer binder,
Examples thereof include, but are not limited to, polycarbonate resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, vinyl acetate resin, nitrocellulose, and phenol resin. The mixing ratio of the polymer binder is not particularly limited, but is preferably 30% or less with respect to the phthalocyanine compound. The film thickness of the recording layer of the present invention varies depending on the type and combination of the phthalocyanine compound of the present invention used as the recording layer.
Although there is no particular limitation, the average film thickness is preferably 300 to 3000 angstroms, and more preferably 500 to 1500 angstroms is the optimum film thickness range in consideration of the irregularities due to the guide grooves formed on the substrate.

The reflective layer that can be used in the present invention includes metals such as gold, silver, copper, platinum, aluminum, cobalt and tin, alloys containing these as the main components, MgO and Z.
Metal oxides such as nO and SnO, SiN, AlN, TiN
Examples of such nitrides include gold, and gold is most suitable because of its high absolute reflectance and excellent stability. As a method for forming such a reflective layer, a dry process, for example, a vacuum deposition method or a sputtering method is most preferable, but the method is not limited to this. The thickness of the reflective layer of the present invention is not particularly limited, but is preferably in the range of 400 to 1300 angstrom. Further, a protective layer for protecting the medium is provided on the recording layer or the reflective layer in order to prevent chemical deterioration (for example, oxidation, water absorption, etc.) and physical deterioration (for example, scratches, abrasions, etc.) of the medium. As a material for the protective layer, a method of applying an ultraviolet curable resin, applying by spin coating, and curing by ultraviolet irradiation is preferable,
It may be vapor-deposited of SiO2 or may be a resin film attached, but is not limited thereto. Regarding the optimum film thickness of the protective layer, when it is thin, the protective effect decreases, and when it is thick, it causes mechanical properties such as warpage of the medium to deteriorate due to shrinkage during curing of the resin. It is preferable to form a film in the micron range.

The transparent substrate used in the present invention preferably has a light transmittance of 85% or more for writing and reading signals and has a small optical anisotropy. For example, glass or acrylic resin, polycarbonate resin, polyester resin, polyamide resin, vinyl chloride resin, polyvinyl ester resin, polystyrene resin, polyolefin resin (for example, poly-4-methylpentene, etc.), polyester Substrates using a thermoplastic resin such as tersulphone resin or a thermosetting resin such as an epoxy resin or an allyl resin may be mentioned. Also, those obtained by evaporating SiO2 or the like on these substrates may be used. Among these, the above-mentioned thermoplastic resins are preferable because of their ease of molding and the ease of providing guide grooves and address signals. In the present invention, the thickness of these transparent substrates is not particularly limited and may be plate-like or film-like. The shape may be circular or card-like, and the size is not particularly limited. In other words, it is not limited to a disc-shaped recording medium such as a general optical disc, and may be an optical card, a tape-shaped recording medium, or a sheet-shaped recording medium. Further, on the transparent substrate of the present invention, a guide groove for position control at the time of recording and reading, a preform for address signals, various marks and the like.
Although it usually has irregularities for mats, it is preferable to apply these irregularities by using a stamper or the like when molding (injection molding, compression molding) the thermoplastic resin as described above. It can also be carried out by the so-called 2P method using a resin.

The shape of the guide groove of the present invention is not particularly limited, and may be a short shape, a trapezoidal shape, or a U-shape. Regarding the dimensions of the guide groove, the optimum values differ depending on the type and combination of the materials used for the recording layer, but the average groove width (width at half the groove depth) is 0.3 to 0. It is preferably 6 microns and the groove depth is in the range of 500 to 2500 angstroms. As with the protective layer on the reflective layer, the laser light incident surface of the transparent substrate is also used for the purpose of preventing chemical deterioration (eg, oxidation, water absorption, etc.) and physical deterioration (scratches, scratches, etc.) of the medium. A protective layer may be provided. As a material for the protective layer, an ultraviolet curable resin is used and a spin coater is used.
However, the method is not limited to this. Regarding the optimum thickness of the protective layer, if it is thin, the effect of protection decreases,
If it is thick, shrinkage of the resin during curing causes deterioration of mechanical properties such as warpage of the medium. Therefore, it is preferable to form a film within a range of 2 to 20 μm. In addition, for the purpose of functions other than the protective layer, such as antireflection, antistatic, and moisture-proofing, a low refractive index material, a fluororesin or a conductive resin, etc. are formed on the transparent substrate at the laser incident surface side and the recording side, like the protective layer. It may be provided on the layer or on the reflective layer.

Recording on the optical recording medium thus obtained is performed by irradiating the recording layer provided on the transparent substrate with a laser beam focused to about 1 micron, preferably a semiconductor laser beam. The laser light irradiation portion of the recording layer undergoes thermal state change such as decomposition, evaporation, melting or diffusion to the substrate due to absorption of laser energy. The reproduction is performed by reading the difference in reflectance between the portion that has undergone thermal change and the portion that has not. The phthalocyanine-based compound used in the present invention has an extremely large difference in reflectance before and after recording, so that the recording signal becomes large and good electrical characteristics can be obtained. As the laser, various lasers such as He-Ne laser, Ar laser, and semiconductor laser can be used.
A semiconductor laser is preferable in terms of size. The semiconductor laser preferably has a center wavelength in the range of 770 to 830 nm, but a laser having a shorter wavelength than that can be used. Typical examples of the optical recording medium to which the present invention can be applied include a write-once CD and a DRA for document files.
Examples thereof include W-type optical discs and write-once type LDs, but the present invention is not limited to these and can be applied to a wide range of optical recording media such as optical tapes and optical cards.

[0026]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to the following examples. Example 1 1200 Angstroms deep, 0.4 microns wide, 1.20 m thick with 1.6 micron pitch guide grooves.
The phthalocyanine compound (1) was dissolved in diacetone alcohol at a concentration of 60 mg / ml on a polycarbonate substrate having a diameter of m, an outer diameter of 120 mm, and an inner diameter of 15 mm, and the coating liquid was adjusted by filtering 0.2 μm. Was used to form a film having a thickness of 1000 angstrom by a spin coater. Next, gold was formed into a film having a thickness of 800 Å on the recording layer thus obtained by sputtering. Further, an optical disc was prepared by providing a protective layer of 5 μm thick with an ultraviolet curable resin on this. An optical disk evaluation device (DDU-1000) manufactured by Pulstec for the optical disk thus created
And a function generator manufactured by Hewlett-Packard, using a wavelength of 785 nm, N. A. = 0.
5 semiconductor lasers with linear velocities of 11 m / sec and 18
The recording / reproducing characteristics of a single signal with m / sec and a frequency of 8.5 MHz were evaluated.

As a result, the reflection level of the laser-irradiated recording area was higher than that of the non-irradiated area, and the C / N ratio was 45 dB or more at a power of 10 mW even at 18 m / sec, and the jitter was 5 nsec or less. This recording / reproducing characteristic is
The characteristics are such that they can be sufficiently applied to high-density recording, and the levels are such that they can be applied to ordinary LD recording signals that FM-modulate video, analog audio, and digital audio signals in the LD-format. In addition, 50
When stored in a high humidity environment of ℃ / 90% RH, 10
The initial C / N ratio was maintained even after 0 hour, and no signal deterioration was observed. Further, as a result of removing the protective film and the reflective film of the optical disk recorded in this way and observing the recording film with a microscope, no pit formation due to the shape change was observed in the recording portion irradiated with the laser. It was Example 2 Depth 1000 Å, width 0.4 micron, pitch 1.6 micron with guide grooves 1.20 m thick
m, an outer diameter of 120 mm, an inner diameter of 15 mm, a 3: 1 mixture of the phthalocyanine compound (2) and an epoxy resin was dissolved in ethyl cellosolve at a concentration of 50 mg / ml, and 0.2 micron filtering was performed to obtain a coating liquid. Was adjusted, and using this coating solution, a film was formed in a thickness of 1000 angstrom by a spin coater. Next, gold was formed into a film having a thickness of 800 Å on the recording layer thus obtained by sputtering. Further, an optical disc was prepared by providing a protective layer of 5 μm thick with an ultraviolet curable resin on this.

Recording and reproduction characteristics of the optical disc thus prepared were evaluated by the same method as in Example 1. As a result, the reflection level of the laser-irradiated recording area is higher than that of the unirradiated area, and the power is 10 m even at 18 m / sec
C / N ratio at W is 50 dB or more, and jitter is 5 ns
It was ec or less. This recording / reproducing characteristic is a characteristic that can sufficiently cope with high-speed and high-density recording, and at a level that can sufficiently cope with a recording signal of a normal LD that FM-modulates each signal of video, analog audio, and digital audio in LD-format. there were. In addition, this optical disc
When stored in a high humidity environment of 90% RH, the initial C / N ratio was maintained even after 100 hours, and no signal deterioration was observed. Further, as a result of removing the protective film and the reflective film of the optical disk recorded in this way and observing the recording film with a microscope, no pit formation due to the shape change was observed in the recording portion irradiated with the laser. It was

Comparative Example 1 Depth of 1000 Å, width of 0.4 μm, pitch of 1.6 μm and guide grooves of 1.20 m thickness.
m, an outer diameter of 120 mm, and an inner diameter of 15 mm, the phthalocyanine compound (10) was dissolved in ethyl cellosolve at a concentration of 30 mg / ml, and the coating liquid was adjusted by filtering 0.2 μm. Then, a film was formed in a thickness of 1000 angstrom using a spin coater. Next, gold was formed into a film having a thickness of 800 Å on the recording layer thus obtained by sputtering. Further, an optical disc was prepared by providing a protective layer of 5 μm thick with an ultraviolet curable resin on this. The optical disk thus produced was evaluated for recording and reproducing characteristics in the same manner as in Example 1. As a result, the reflection level of the laser-irradiated recording area was higher than that of the non-irradiated area, and even at 18 m / sec, C /
The N ratio was 45 dB or more, and the jitter was 5 nsec or less. Furthermore, this optical disk is 50 ° C / 90% R
When stored under a high humidity environment of H, the C / N ratio decreased to 10 dB after 100 hours, and clear signal deterioration was confirmed.

Phthalocyanine compound (10)

[Chemical 12]

[0031]

By the constitution of the optical recording medium using the optical recording material of the present invention, moisture resistance is improved by stabilizing residual substituents unstable in the recording film with respect to humidity, and the conventional laser light is used. It is possible to provide an optical recording medium having moisture resistance that can be used at a practical level while maintaining high-speed and high-precision recording characteristics that do not cause shape change due to.

Claims (2)

[Claims] 1. A recording film material for an optical recording medium comprising a phthalocyanine compound represented by the general formula [1]. General formula [1] [In the formula, M is Si (OH) ₂ , Ge (OH) ₂ , Al (O
H), Ga (OH) and In (OH). R1 and R2
Each independently represents a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent. R3 represents a metal or an amino compound. m and n each independently represent an integer of 1 to 4. ] 2. A write-once type optical recording medium comprising a transparent substrate / recording film / reflection film / protective film for recording / reproducing with a laser beam, the recording film being selected from a phthalocyanine compound represented by the general formula [1]. A write-once type optical recording medium comprising one or more phthalocyanine compounds described above.