JPS63139789A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium which has preferable recording characteristics and can be easily corresponding to various types of semiconductor lasers by using asymmetrical phthalo.naphthalocyanine colorant of large cyclic base cyclized compound for a recording layer. CONSTITUTION:An optical recording medium having a recording layer made of large cyclic base cycle organic colorant is provided. The base cycle is novel asymmetrical phthalo.naphthalocyanine colorant molecule which has at least benzene cyclic skeleton and at least one naphthalene cyclic skeleton in the base cycle unit and metal or metal including substituted group disposed in the center of the base cycle. This medium, since having novel large cyclic base cyclized structure in a recording layer itself, has a sufficient reflectively to be able to write or read a signal without a reflecting layer of thin metal film or metal oxide thin film, and can obtain, since its reflectivity is large, large S/N ratio, and simultaneously improves recording density. It is stable for heat and moisture to be available for a long term use to correspond to a semiconductor laser having various oscillation wavelengths while holding the high S/N ratio.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an optical recording medium that can be additionally recorded using a focused beam of a semiconductor laser, and more specifically relates to a computer external memory, various types of information such as images, audio, etc. The present invention relates to an optical recording medium used for recording.

[Prior art]

The above-mentioned recordable optical recording medium includes a recording medium having an inorganic recording layer made of a thin film of a low-melting metal such as tellurium, a tellurium alloy, and a bismuth alloy, and, for example, U.S. Pat.
A recording medium having a phthalocyanine dye film as a recording layer as disclosed in No. 75 has been proposed.

However, these recording media have low productivity because they require formation of the recording layer in a vacuum using vacuum evaporation, sputtering, etc., and media with inorganic recording layers have high thermal conductivity of the recording layer. has a limit in terms of recording density. Furthermore, since these use toxic substances such as tellurium, there are concerns about toxicity.

On the other hand, for media with a phthalocyanine dye as a recording layer, the optical properties of the recording layer do not match the oscillation wavelength of the semiconductor laser, so the recording film, which is usually obtained by vapor deposition, is exposed to heat or organic solvent vapor, a process known as shifting. However, this shifting process is complicated and requires a long process time of 1 to 72 hours, so it has not been put to practical use.

In order to solve the above-mentioned problems, media have been proposed in which a recording film is formed by a coating method using a soluble dye. A method of coating an organic dye that has absorption in the region and is soluble in an organic solvent using a spin coding method has been developed and has been put into practical use to some extent. However, among the dyes that have been proposed so far, for example, cyanine Media with recording layers made of dyes or squalium dyes lacked durability. Further, since the reflectance of a dye film made of a dithiol metal complex alone is essentially low, a separate reflective layer made of an inorganic compound such as a metal thin film or a metal oxide thin film is required.

In contrast, recording media using naphthalocyanine dyes have recently been proposed. For example, U.S. Pat. No. 4,492,75
No. 0 relates to a medium using an alkyl-substituted naphthalocyanine dye, and in this patent, a reflective layer such as A1 was provided on a glass or polymethyl methacrylate substrate, and the layer was treated with organic solvent vapor. , oosμ~0.1
An optical recording medium is disclosed that includes an optical recording layer composition in which alkyl-substituted naphthalocyanine dye particles having a particle size of .mu. are dispersed in a resin binder. In this way, it is not possible to form a recording layer made of an organic dye directly on the substrate, and it is necessary to form a reflective layer made of an inorganic compound such as A1 on the substrate separately from the recording layer using a vacuum process such as vapor deposition. This means that the manufacturing process for optical recording media becomes more complicated. What is even more problematic is that organic pigment films inherently have low thermal conductivity, so they are expected to provide high recording sensitivity, but metallic or inorganic pigment films with high thermal conductivity When a metal reflective layer is provided, due to the high thermal conductivity of the metallic reflective layer, the thermal energy generated by the writing laser beam irradiated to the recording layer is dissipated through the metallic reflective layer, resulting in bits (corresponding to signals). This is because the recording sensitivity is not effectively used to form unevenness (concavities and convexities), resulting in a significant decrease in recording sensitivity. Naturally, when a reflective layer made of an inorganic compound such as A2 is provided,
When a laser beam for recording or reading signals is irradiated from the substrate side, even if the substrate itself is transparent, the laser beam is blocked by a metal reflective layer that does not substantially transmit light and reaches the recording layer. Therefore, when a reflective layer is provided, recording and reproduction of signals cannot be performed through the substrate, and must be performed from the recording layer side. Even dust and scratches can greatly interfere with the normal recording and reproduction of uneven signals.

Therefore, for practical use, an overcoat or the like is required as a protective layer on the recording layer. If it is possible to record and reproduce signals by irradiating a laser beam through a transparent substrate, the presence of dust and scratches on the side where the laser beam enters, that is, on the medium surface before the laser beam is focused, will be eliminated from the substrate. A protective layer is not necessary because it does not substantially affect the recording and reproduction of signals due to the gap equivalent to the thickness of Media provided with this have a number of drawbacks.

It is desired to develop an optical recording medium in which a highly durable organic dye is formed as a recording layer by a coating method, in which signals can be recorded and reproduced without the need for a separate reflective layer made of an inorganic compound. was.

Also, JP-A-61-177287, JP-A-61-17
No. 7288 and JP-A No. 61-235188 also relate to recording media using specific naphthalocyanine dyes, but in reality, reflectance data are only given for silicon naphthalocyanine whose central metal is silicon. Only.

Also, it is true that the absorption wavelength of naphthalocyanine dyes shifts to the long wavelength side compared to phthalocyanine dyes, making it easier to match with the oscillation wavelength of the semiconductor laser, 813s5, but in some cases, the absorption wavelength shifts to the long wavelength side. We have also confirmed that shifting too much often results in gaps.

The oscillation wavelength of semiconductor lasers currently in practical use as laser beam light sources is approximately 750n+s to 850nm, and semiconductor lasers having various oscillation wavelengths are used depending on the design of optical recording medium reproducing and writing devices. Therefore, in consideration of the above issues, we have developed an organic material that best matches the reflection and absorption wavelength ranges to the specific oscillation wavelength of the semiconductor laser used, and that is also capable of recording and reproducing signals while maintaining durability. There has been a desire to develop optical recording using a dye as a recording layer.・ [Basic idea] The present inventors conducted intensive studies to improve the above-mentioned drawbacks of optical recording media with an organic dye film as a recording layer. By using an asymmetric phthalo-naphthalocyanine dye, which is a new macrocyclic returning compound containing both phthalocyanine ring skeletons, in the recording layer, we have achieved durability that could not be achieved with optical recording media using conventional organic dyes. In addition, since the recording layer itself has the function of a reflective layer, it is possible to form an optical recording medium that does not require a separate reflective layer made of an inorganic compound.
By using naphthalocyanine dyes, good recordings that cannot be obtained with conventional recording films using a single phthalocyanine compound or naphthalocyanine compound, or a simple mixture of a phthalocyanine compound and a naphthalocyanine compound can be achieved. The present invention was completed based on the discovery that it is possible to obtain an optical recording medium that has the following characteristics and is easily compatible with various semiconductor lasers.

[Disclosure of the invention]

That is, the present invention provides an optical recording medium having a recording layer made of an organic dye of a macrocyclic ring, wherein the macrocyclic ring has at least one benzene ring skeleton in one unit of the macrocyclic ring. and at least one naphthalene ring skeleton (however, the benzene ring skeleton or the naphthalene ring skeleton may be unsubstituted or have a substituent -Z), and a metal or a substituent at the center of the macrocyclic ring. An optical recording medium characterized by being a novel asymmetric phthalo-naphthalocyanine dye molecule coordinating a metal having .

The present invention will be explained in detail below.

In the present invention, the asymmetric phthalo-naphthalocyanine dye used specifically has the following general formula (Ic formula, where h is 2
hydrogen atoms, metals or metal oxides, Y represents its substituent, n・0.1 or 2, L+, Lm
, Ls, and represent a benzene ring skeleton or naphthalene ring skeleton that is unsubstituted or has a substituent or 2, and Ll
+ At least one of Lg, Ls, and M4 is a benzene ring skeleton, and is represented by a small number (one of which represents a naphthalene ring skeleton).

In the optical recording medium of the present invention, a recording layer made of such an organic color patch is provided on a transparent substrate, and signals are recorded and read out by a light beam passing through the transparent substrate. As a substrate, the light transmittance for writing and reading signals is preferably 85.
% or more and with small optical anisotropy is desirable 0 For example, plastics such as acrylic resin, polycarbonate resin, allyl resin, polyester resin, polyamide resin, vinyl chloride resin, polyvinyl ester resin, epoxy resin, polyolefin resin, etc. Preferred examples include glass. Among these, plastics are particularly preferred from the viewpoints of mechanical strength of the substrate, ease of providing guide grooves, address signals, etc., and economic efficiency.

The shape of these transparent substrates may be plate-like or film-like, or may be circular or card-like.

Of course, the surface may have guide grooves indicating the recording position, irregularities for address signals, etc.

Such guide grooves, address signals, etc. can be added when the substrate is used by injection molding or casting, or they can be added by applying ultraviolet curable 9M resin or the like on the substrate, overlapping it with a stamper, and exposing it to ultraviolet rays. can.

In the present invention, on such a substrate, one macrocyclic ring unit represented by the above formula (1) contains at least one benzene ring skeleton and at least one naphthalene ring skeleton (but the benzene ring skeleton Alternatively, the naphthalene ring skeleton may be unsubstituted or may have a substituent -Z), and a novel asymmetric phthalo-naphthalocyanine dye molecule in which a metal or a metal having a substituent is coordinated to the macrocyclic ring center. A recording layer containing the same is provided.

The most distinctive feature of the present invention is the use of such an "asymmetric phthalo-naphthalocyanine dye", which has never been proposed or even suggested, in the recording layer. However, the term "asymmetric" used here was named to emphasize the structural specificity of conventional phthalocyanine dyes or naphthalocyanine dyes, and the term "asymmetric" is used to emphasize the structural specificity of conventional phthalocyanine dyes or naphthalocyanine dyes. If "all" of the skeleton is a benzene ring skeleton (phthalocyanine compound) or a naphculene skeleton (naphthalocyanine compound), we will call it ``symmetrical.''
It is used as a concept for this.

In other words, a unique structure containing both a phthalocyanine skeleton and a naphthalocyanine skeleton simultaneously in one macrocyclic ring unit is called ``asymmetric J.''

Examples of such "asymmetric phthalo-naphthalocyanine dyes" include the following.

2゜In the asymmetric phthalo-naphthalocyanine dye represented by the general formula (1) used in the recording layer in the present invention, substituent-2 of the benzene ring skeleton or naphthalene ring skeleton
Examples include halogens such as C1, Br, and I, hydroxyl groups,
mercapto groups, carboxyl groups, sulfonic acid groups, amido groups, sulfonamide groups, aldehyde groups, thioaldehyde groups, and those containing carbon atoms and hydrogen atoms, and carbon atoms and hydrogen, silicon, oxygen, nitrogen, selenium, sulfur, and phosphorus. and an organic substituent containing an atom selected from halogen.
Examples include R. Examples of -R include an alkyl group, an aryl group (Aryl), an alkylcarbonyl group, an aroyl group, an alkanethiol group, an alkanimidoyl group, an arylimidoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, and an alkoxy group. , aryloxy group, alkylamino group, arylamino group, alkylamido group, arylamide group, alkylthio group,
Arylthio groups, alkylsulfinyl groups, arylsulfinyl groups, alkylsulfonyl groups, arylsulfonyl groups, alkylsilyl groups, arylsilyl groups, alkylsilyloxy groups, silyloxy groups, alkylselenyl groups, arylselenyl groups, etc. are preferred. It is mentioned as a thing.

Other substituents may be connected to the extension of the main chain or to the side chain, and other substituents may be connected to the aromatic ring if an aryl group is present.

Examples include an alkylaryl group, an alkyl alkyl group, an alkenyl alkyl group, an alkylalkyl group, an alkoxyalkyl group, an alkoxyalkyl group, and the like.

In addition, double bonds, triple bonds, halogens, hydroxyl groups, mercapto groups, carboxyl groups, sulfonic acid groups, amide groups, sulfonamide groups, aldehyde groups, thioaldehyde groups, sulfonamide groups, and epoxy groups are present at the terminals of these substituents. It may be modified or linked with polymers such as polyamide, polyester, polyurethane, polyether, etc.

In addition, these substituents are usually -valent, but may be divalent or more. For example, in the case of divalent, the substituent is bonded to a carbon atom adjacent to the benzene ring or naphthalene ring, or the same Bonded to other benzene or naphthalene rings in the molecule.

More specific examples of the substituent -R are as follows.

Alkyl groups include methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, decyl, etc.; cycloalkyl groups include dodecylcyclohexyl, methylcyclohexyl, butylcyclohexyl, etc.; alkenyl groups include vinyl, Allyl, etc.; cycloalkenyl groups include cyclohexene,
Methylcyclohexene, butylcyclohexene, etc.;
Aromatic hydrocarbon groups containing aryl groups include phenyl,
Preferred examples include biphenyl, methylphenyl, dimethylphenyl, hexylphenyl, benzyl, phenylbutyl, and naphthyl.

In addition, alkoxy groups include methoxy group, ethoxy group,
n-propioxy group, 1so-propioxy group, n-butoxy group, 5ec-butoxy group tert-butoxy group, 1
so-butoxy group, n-pentoxy group, 1so-pentoxy group, 5ec-pentoxy group, tert-pentoxy group, n-hexoxy group, 1so-hexoxy group, 1-
Methyl-1 ethylpropioxy group, 1,1-dimethylbutoxy group, n-hebutoxy group, 1so-hebutoxy group,
5ec-hebutoxy group, tert-hebutoxy group, octoxy group, 2-ethylhexoxy group, nonyloxy group,
Decyloxy group, dobutyloxy group, cyclohexyloxy group, methylcyclohexyloxy group, etc.; As alkenyloxy group, butenoxy group, hexeneoxy group, octeneoxy group, dodeceneoxy group, cyclohexeneoxy group, methylcyclohexeneoxy group, etc.; as aryloxy group, phenoxy group, group, methylphenoxy group,
Examples include ethylphenoxy group, dimethylphenoxy group, butylphenoxy group, hexylphenoxy group, benzyloxy group, phenylethoxy group, and phenylhexoxy group.

Examples of the alkylsilyl group include trimethylsilyl group, triethylsilyl group, tributylsilyl group, trihexylsilyl group, trioctylsilyl group, and triphenylsilyl group.

Examples of alkylcarbonyl groups and aroyl groups include acetyl group, ethylcarbonyl group, propylcarbonyl group,
Butylcarbonyl group, pentylcarbonyl group, hexylcarbonyl group, heptylcarbonyl group, octylcarbonyl group, nonylcarbonyl group, decadylcarbonyl group,
Examples include a dodecylcarbonyl group, a cyclohexylcarbonyl group, a benzoyl group, a ter't-butylbenzoyl group, a heptylbenzoyl group, an octylbenzoyl group, and a dodecanylbenzoyl group.

As the alkoxycarbonyl group and allyloxycarbonyl group, methoxycarbonyl group, ethyloxycarbonyl group, propyloxycarbonyl group, butyloxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, heptyloxycarbonyl group, octyloxycarbonyl group, Nonyloxycarbonyl group, decasyloxycarbonyl group, dodecasyloxycarbonyl group, cyclohexyloxycarbonyl group, phenyloxycarbonyl group, and tart-butylphenyloxycarbonyl group, heptylphenyloxycarbonyl group, octylphenyloxycarbonyl group, dodeca Examples include nylphenyloxycarbonyl group.

Examples of the alkanethiol group include an ethanethioyl group, a propanethiol group, a hexanethioyl group, an octanethiol group, and a nonanthioyl group.

As the alkanimidoyl group, ethanimidoyl group,
Examples include propaneimidoyl group, hexaneimidoyl group, octaneimidoyl group, and nonaneimidoyl group.

Examples of the alkylamino group and arylamino group include methylamino group, ethylamino group, pro-rulamino group, butylamino group, pentylamino group, hexylamino group,
Heptylamino group, octylamino group, nonylamino group, decasylamino group, dodecasylamino group, cyclohexylamino group, benzylamino group, and tert-butylphenylamino group, heptylphenylamino group, octylphenylamino group, dodecanylphenylamino group , piperidinyl group, etc.

Examples of the alkylcarbonylamino group and arylcarbonylamino group include methylcarbonylamino group, ethylcarbonylamino group, propylcarbonylamino group, butylcarbonylamino group, pentylcarbonylamino group, hexylcarbonylcarbonylamino group, heptylcarbonylamino group, and octylcarbonylamino group. Amino group, nonylcarbonylamino group, decadylcarbonylamino group,
dodecadylcarbonylamino group, cyclohexylcarbonylamino group, benzylcarbonylamino group, and t
Examples include ert-butylphenylcarbonylamino group, heptylphenylcarbonylamino group, octylphenylcarbonylamino group, dodecanylphenylcarbonylamino group.

Examples of the alkylthio group and arylthio group include methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, hexylthio group, heptylthio group,
Octylthio group, nonylthio group, decasylthio group, dodecasylthio group, cyclohexylthio group, benzylthio group, and Lert-butylphenylthio group, heptylphenylthio group, octylphenylthio group, dodecanylphenylthio group, naphthylthio group, anthrylthio group, etc. can be given.

Examples of the alkylsulfinyl group and arylsulfinyl group include methylsulfinyl group, ethylsulfinyl group, propylsulfinyl group, butylsulfinyl group,
Pentylsulfinyl group, hexylsulfinyl group, heptylsulfinyl group, octylsulfinyl group, nonylsulfinyl group, decasylsulfinyl group, dodecasylsulfinyl group, cyclohexylsulfinyl group, benzylsulfinyl group, and tert-butylphenylsulfinyl group, heptyl phenyl group sulfinyl group,
Examples include octylphenylsulfinyl group, dodecanylphenylsulfinyl group, and naphthylsulfinyl group.

Examples of the alkylsulfonyl group and arylsulfonyl group include methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, butylsulfonyl group,
Pentylsulfonyl group, hexylsulfonyl group, heptylsulfonyl group, octylsulfonyl group, nonylsulfonyl group, decasylsulfonyl group, dodecasylsulfonyl group, cyclohexylsulfonyl group, benzylsulfonyl group, and jet-butylphenylsulfonyl group, heptyl phenyl group sulfonyl group,
Examples include octylphenylsulfonyl group, dodecanylphenylsulfonyl group, and naphthylsulfonyl group.

On the other hand, specific examples of h in the asymmetric phthalo-naphthalocyanine dye represented by the general formula (1) include two hydrogen atoms; a group Ib metal of the periodic table such as Cu; Mg;
Group II metals such as Ca, Sr, Zn, and Cd; A
j! , , Ga, In5T l and other group metals;
Si, Ge, Sns Pb, Ti%Zr,) If
Group ■ metals such as Sb, Bi.

Group V metals such as V, Nb%Ta, HSs, Te
, CrSMo.

■Group metals such as Cot Hit Ru, Rh, Pd+
Examples include group II metals such as Os, Ir, and Pt, and oxides of these metals. These metals and metal oxides are usually divalent, but may be a mixture of monovalent and trivalent. The body may be
Alternatively, it may be a dimer in which i is sandwiched between macrocyclic molecules.

h may be a metal or metal oxide having a substituent -Y, but in the present invention, the substituent represented by -Y includes a hydroxyl group, a mercapto group, an isocyano group, a siloxy group,
Halogens such as chlorine, bromine, and iodine, and those mentioned above as substituent -2 of the naphthalocyanine ring skeleton can also be used as -Y as they are. Note that the substituent -V may have one or two chambers I^ depending on the valence of the central metal, but in the case of two substituents, the types of substituents may be different.

In addition, the asymmetric phthalo compound represented by the general formula (1) of the present invention
The total number of carbons contained in all the above-mentioned substituents -Z and -Y in one molecule of the naphthalocyanine dye is preferably 16 or more from the viewpoint of solubility of the dye in a solvent. The total number of substituents-2 is not particularly limited, but from the viewpoint of solubility, it is preferably 3 or more, and more preferably 4 or more.

There are no particular restrictions on the way in which the above-mentioned substituents are introduced, and they may be bonded to any position on the benzene ring or naphthalene ring. The substituents may be bonded to the rings on average, or may be bonded to only one benzene ring or naphthalene ring, or may be in an intermediate state, and even if the types of substituents are the same. It doesn't matter if they are different.

In addition, i in general formula (1) is Cot Hit Mg+
Pd+ Cot Nb+ Sn+ In, Ge,
Ga, VO, TiO and Aj! , Ga, In chloride, boomite, or oxide, and those having a substituent -V are preferable from the viewpoint of absorption and reflection of semiconductor laser light by the dye film.

The asymmetric phthalo-naphthalocyanine dye used in the present invention can be produced by simply reacting precursors having different aromatic rings, such as a benzenedinitrile derivative and a naphthalenedinitrile derivative, and other methods known in the art. For example, phthalocyanine dyes and naphthalocyanine dyes that can be
The asymmetric phthalo-naphthalocyanine of the present invention can also be synthesized according to these methods. can. However, according to the inventors' studies, this method:
- The ratio of the number of benzene ring skeletons and naphthalene skeletons in the molecule (one macrocyclic ring unit) is 4:0, 3:l, respectively.
2:2.1:3 or 0:4 products,
That is, a mixture of several JIB of asymmetric phthalo-naphthalocyanine dyes, phthalocyanine dyes and naphthalocyanine dyes is obtained.

Therefore, after the completion of the synthesis reaction, the benzene ring skeleton and the naphthalene ring skeleton are separated into the molecule by an appropriate separation means such as column separation in a ratio of 4:O, 3:1.2:2.1:3, respectively.
．． It is possible to separate into components containing 0:4.

Conventionally, such asymmetric phthalo-naphthalocyanine compounds have not been known at all, and when precursors having different aromatic rings are mixed and reacted, the phthalocyanine ring changes into a phthalocyanine ring in the process of winding the ring. Since it is generally thought that naphthalocyanine rings are formed as separate molecules, it is extremely surprising that a new asymmetric phthalo-naphthalocyanine dye can be synthesized by the method described above.

These compound groups obtained as described above were confirmed by analytical means such as elemental analysis, infrared spectroscopy, NMR, and FD-MS.

In order to fix (form) the recording layer on the transparent substrate in the optical recording medium of the present invention, for example, an asymmetric phthalo-naphthalocyanine dye can be fixed by methods such as vacuum evaporation, sputtering, and ion blating. Since these methods require complicated scraping and are poor in productivity, so-called coating methods are most preferred.

To fix the recording layer by coating, a dye solution consisting of the above-mentioned asymmetric phthalo-naphthalocyanine dye and an organic solvent described below is brought into contact with the substrate to fix the dye on the substrate. There is a method in which the dye liquid is allowed to flow down onto the surface of the substrate, or after the surface of the substrate is brought into contact with the liquid level of the dye liquid and then the excess liquid is removed while rotating the substrate. There is a method of causing the liquid to flow down onto the substrate. If necessary, forced drying by heating may be performed after this. The organic solvent used at this time may be a conventional solvent that dissolves the asymmetric phthalo-naphthalocyanine dye, such as benzene,
Toluene, xylene, ethylbenzene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetylacetone, ethyl acetate, butyl acetate, amyl acetate, cellosolve, methyl cellosolve, butyl cellosolve,
Examples include cellosolve acetate, diglyme, chloroform, carbon tetrachloride, methylene chloride, methylchloroform, tricrene, and dimethylformamide. In selecting a solvent, it is preferable to use a solvent that does not damage the guide grooves on the transparent substrate in addition to the solubility of the dye.

The concentration of the dye solution in the present invention varies depending on the type of solvent and coating method, but is usually 0.1 to 10% by weight, preferably 0.3z to 5% by weight. At this time, in the present invention, in order to increase the reflectance of the recording film or improve sensitivity, other soluble dyes may be added to the dye solution in an amount that does not impede the effects of the present invention, for example, approximately less than 50% of the total amount of dyes used. It is also possible to mix and use within a range. Examples of dyes that can be used in combination include known ones, such as aromatic or unsaturated aliphatic diamine gold IEii, aromatic or unsaturated aliphatic dithiol metal complexes, substituted phthalocyanine dyes, substituted naphthalocyanine dyes, and polymethine dyes. , squalium pigments, naphthoquinone pigments, and anthraquinone pigments.

In the present invention, in order to improve the smoothness of the recording film and reduce defects such as pinholes when forming the recording film, the phthalo-naphthalocyanine dye of the present invention and, if necessary, the phthalo-naphthalocyanine dye described above are used. Addition of soluble resin such as nitrocellulose, ethyl cellulose, acrylic resin, polystyrene, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinyl butyral, polyester resin, leveling agent, antifoaming agent, etc. to the solution with other dyes. However, adding a large amount of these resins or additives may reduce the reflectance of the recording layer, or the dye may not dissolve uniformly in the recording film and become dispersed, resulting in a decrease in recording sensitivity. In addition, the reflectance also decreases. From these points of view, the amount of the resin and additives added is less than 20 weight percent, preferably 10 weight percent or less, and more preferably 5 weight percent or less in the recording film. In other words, in the present invention, the total amount of the phthalo-naphuclocyanine dye in the recording layer and the dye that can be mixed and used as described above is at least 80% by weight to 100 parts by weight, preferably 9.
0% to 100% by weight, more preferably 95% by weight
~100% by weight.

Regarding the optical recording medium of the present invention, as described above, it is preferable to record and reproduce signals using a laser beam (light beam irradiated from the substrate side) through a transparent substrate.In such a case, the recording layer If the film thickness becomes too thick, the writing light will be absorbed and attenuated considerably as it passes through the thick recording layer, and will not sufficiently reach the surface of the recording layer (the surface in contact with air). Therefore, the amount of light on this surface is insufficient and the temperature rise is insufficient, making it impossible to satisfactorily form the unevenness that corresponds to the signal.As a result, the sensitivity decreases, and even if it is possible to record the signal, it is difficult to read out the signal. The S/N value (signal-to-noise ratio) value is small and cannot be put to practical use. On the other hand, if the thickness of the recording layer is too thin, as will be described later, a sufficient reflectance in the recording layer cannot be obtained due to light interference, and therefore a large S/N value cannot be obtained.

Therefore, it is necessary to form a recording layer with an appropriate thickness, and the thickness of the recording layer in the optical recording medium of the present invention is preferably from 50 to 3,000 mm, more preferably from 60 to 250 r++w.

There are various methods for measuring film thickness, and it is quite difficult to obtain an accurate measurement value. Although it is particularly difficult to measure film thickness when there are guide grooves on the substrate, it is preferable to use pregro
It is also possible to use the film thickness obtained when the dye is fixed on a substrate that does not have an ove) as a substitute.

The most characteristic feature of the present invention is that the recording layer formed in this way has a fairly high reflectance, and therefore the recording layer itself also functions as a reflective layer. It is something that we have at the same time.

Therefore, the optical recording medium of the present invention is capable of controlling the focus of a laser beam when recording or reading signals without providing any reflective layer made of an inorganic compound such as a metal thin film, metal oxide, or metal alloy thin film as in the past. This makes it possible to control the writing position of signals.

Generally, in order to write a signal on an optical recording medium, the recording layer is irradiated with a focused laser beam. The dye in the recording layer in the irradiated area absorbs the laser beam and generates heat, causing the recording layer to change in quality, forming irregularities and changing the reflectance, thereby performing writing. Signals are read by detecting this change in reflectance using a laser beam, but generally, if this change in reflectance is small, the signal-to-noise ratio (S/N) is undesirable.

However, what should be noted here is that the mode in which the reflectance of the optical recording medium changes when recording is performed, that is, the way in which the reflectance changes when unevenness is formed, is This is completely different depending on the configuration of the recording layer of the medium. For example, in the case of a medium consisting of two layers, a light-reflecting layer and a light-absorbing layer, as disclosed in US Pat. No. 4,219,826, unevenness is formed in the light-absorbing layer. The covered reflective layer is exposed, and therefore the reflectance of the uneven portion increases after recording. Therefore, in such a case, it is sufficient that the initial reflectance (that is, before the unevenness is formed) is such that the laser beam can be controlled.

On the other hand, as in the present invention, the recording layer having a reflective layer is a so-called single layer (nonolayer) that serves as both a light reflective layer and a light absorbing layer.
), the situation is completely opposite,
Due to the formation of irregularities, the reflectance of that portion decreases. That is, the reflectance of the uneven portion becomes lower than the unique reflectance that the recording layer originally had. In such cases, in order to obtain a large S/N value, the original reflectance through the substrate must be small ((
Both are 10% or more, preferably 15% or more.

This reflectance of 10% or more, preferably 15% or more can be easily achieved by using the dye of the present invention and appropriately selecting the thickness of the recording layer. It changes depending on the film thickness due to interference from reflected light from the front and back sides of the recording layer.

Hereinafter, for convenience, the asymmetric phthalo-naphthalocyanine dye compound of the present invention, that is, a novel macrocyclic compound containing a different type of aromatic ring, will be described with reference to the substituent -phthalo(n).
・It will be expressed as naphthalocyanine-centered metal'. Here, n represents the number of benzene skeletons included in the macrocyclic chain, m represents the number of naphthalene skeletons included in the macrocyclic chain, and ta + nm4
holds true.

For example, tetra-butyl-phthalo (1), naphthalo (3
) Cyanine vanadyl represents an asymmetric phthalo-naphthalocyanine vanadyl represented by formula (n).

Therefore, we have the above tetra-butyl-phthalo (1).
FIG. 1 shows the results of measuring the relationship between film thickness and reflectance when a film consisting essentially only of naphthalo(3)cyanine vanadyl was used for the recording layer. In this case, the reflectance was measured using a light source with a wavelength of 830n+w, fixing the recording layer on a transparent substrate with no unevenness such as guide grooves, and using a spectrophotometer equipped with a 5" specular reflection accessory. However, in the present invention, the reflectance refers to the value measured in this way.When light is irradiated through the substrate, the reflection occurs between the substrate and the recording film. This occurs at the interface and the interface between the recording film and air.These two reflected lights interfere with each other and vary depending on the thickness of the recording layer, as shown in Figure 1.Therefore, in the present invention, the film thickness is appropriately selected. By doing so, a desired reflectance can be obtained.

There are still three types of tetra-hebutyl-phthalo (n) and naphthalo (s) cyanine vanadyl [i.e., tetra-hebutyl-phthalo (1), naphthalo (3) cyanine vanadyl, and tetra-hebutyl 1 phthalo (2). Naphthalo(2) cyanine vanadyl, tetra-hebutyl-phthalo(3)/naphthalo(1) cyanine vanadyl] about 110 nm
Figure 2 (1) shows the wavelength dependence of the reflectance and transmittance of the recording layer measured through the acrylic resin plate when a recording layer with a film thickness of 1.2 - 1 is coated on a flat acrylic resin plate.
As is clear from Figure 0 shown in (2), the recording layer has 73
It has a broad absorption of about 100 nm in the range of 0 to 850 nm, shifted by about 20 nm. The wavelength range of this absorption not only closely matches the emission wavelength of the semiconductor laser, but also allows the most suitable macrocyclic phthalo-naphthalocyanine dye to be selected according to the characteristics of the semiconductor laser used.

Further, the reflectance in this wavelength range is 15% or more, and particularly in the 780 to 850 nm range, it has a reflectance of 20% or more. As is clear from FIG. 2, the recording film of the present invention has large absorption and reflectance in the laser emission wavelength range even without organic solvent vapor treatment.

For further comparison, Figure 3 shows the spectrum showing the wavelength dependence of absorption and reflection of a recording layer made by simply mixing tetra-heptyl-naphthalocyanine-vanadyl and tetra-heptyl-naphthalocyanine-vanadyl at a ratio of 1:3. 1),
The substrate shown in (2) is the same acrylic resin plate as in the above example, and the film thickness is approximately Lion-.

As is clear from the comparison between Figure 2, which shows the results when using the asymmetric phthalo-naphthalocyanine dye of the present invention, and Figure 3, which shows the results when the phthalocyanine dye and naphthalocyanine dye were simply mixed, it is clear that the mixture was used. The absorption of the recording layer in this case is broader than that of the asymmetric phthalo-naphthalocyanine dye in the present invention, but the absorption is much weaker with respect to the film thickness. Even in the wavelength range of 780 to 850 mm, the reflectance is It can be seen that this results in a fatal drawback in that it ends up being less than 15%. In other words, the good properties as an optical recording medium as seen in the present invention cannot be achieved by mixing single substances, but can only be achieved by creating an "asymmetric molecule" in which different aromatic ring skeletons are introduced into one molecule. It is.

In addition, in the present invention, the amount of resin binder used is
Preferably, it is unnecessary, and if used, it is at most less than 20%. lIL, U.S. Patent 4,49
As disclosed in No. 2.750, in the region where the amount of resin binder is as high as 40 to 99% by weight, preferably 60 to 90% by weight2, the pigment is not uniformly dissolved in the binder, and the pigment particles are dispersed. As a result, the spectral characteristics of the dye will not match the emission wavelength of the laser unless it is treated with organic solvent vapor.On the other hand, in the region where the amount of resin binder is much smaller, from 0 to less than 20% by weight, as in the present invention. Surprisingly, even though similar dyes are used, they have large absorption in the laser emission wavelength range even without organic solvent vapor treatment. The exact reason for this is unknown, but it is probably because the state of association between dye molecules or the crystal structure varies greatly depending on the amount of resin binder.As a feature of the present invention, the resin binder (binder) is It is also possible to form a recording layer using substantially only an asymmetric phthalo-naphthalocyanine dye without using it. Furthermore, in the present invention, it is thought that by introducing different aromatic rings into the macrocyclic carrier, the state of association between molecules changes and the reflectance is improved. When produced, the resulting membranes are poor in mechanical strength. Therefore, the mechanical strength of the pigment film was improved by adding a large amount of resin as Pai Goo to the organic pigment.
Even though the specific dye of the present invention has a much lower amount of binder or no binder, a recording film made essentially of the phthalo-naphthalocyanine dye alone has sufficient mechanical strength to be used as an optical recording medium. I understand.

When putting the optical recording medium of the present invention into practical use, an antireflection layer may be provided to improve the S/N value, or an ultraviolet curing resin or the like may be coated on the recording layer for the purpose of protecting the recording layer. It is also possible to use a combination of methods such as pasting a protective sheet on the recording layer surface or pasting two sheets together with the recording layer surfaces facing inside, but it is better to create an air gap on the recording layer when pasting them together. desirable.

In addition, the laser beam used for recording and reading in the present invention has a wavelength of 730 to 870 nm, preferably 75 nm.
It is a semiconductor laser having an emission wavelength of 0 to 860n-. For example, when recording with 5w8, the laser output on the substrate surface should be about 41 to 12a+W, and the readout output should be about 1/10 of the recording output.
It may be about 4 mW to 1.2+wW.

[Preferred form for carrying out the invention]

Hereinafter, preferred embodiments of the present invention will be explained with reference to Examples.

In the explanations in the examples, the novel macrocyclic compound of the present invention containing a different type of aromatic ring is expressed as, for example, "substituent - fuculo(n)/naphthalo(m) cyanine central metal", where n is included in the macrocyclic carrier. m represents the number of benzene ring skeletons included in the macrocyclic structure, and m represents the number of naphthalene ring skeletons included in the macrocyclic carrier.

Example 1 (1) A spiral guide groove with a thickness of 1.2m++m and a diameter of 130mm (depth 70nm, width 0.6μ, pitch 1
．． Tetra-butyl-phthalo (1) in the center of the surface with the guide groove of the acrylic resin plate having a
After dropping a solution consisting of 1.2 parts by weight of naphthalo(3) cyanine vanadyl dye and 98.8 parts by weight of carbon tetrachloride, the acrylic resin plate was rotated at a speed of 1100 Orp for 10 seconds.

Next, this acrylic resin plate was dried in an atmosphere of 40° C. for 10 minutes to fix a recording layer substantially consisting only of tetra-butyl-phthalo(1)/naphthalo(3) cyanine vanadyl dye to the acrylic resin plate. The thickness of this recording layer was 95n+m when measured in cross section using a microscope. Further, the reflectance of light having a wavelength of 830 nm through the acrylic resin plate was 26%.

(2) Place the thus produced optical recording medium on a turntable with the recording layer facing up, and while rotating it at a speed of 900 rpm, a semiconductor laser having an oscillation wavelength of 830 n- and an output of 8 mW at the substrate surface is Using the equipped optical head, a 1 MHz pulse signal (ds+Ly 50
%) was recorded using the same equipment, the output of the semiconductor laser was set at 0°7d on the substrate surface, and the recorded signal was reproduced in the same manner. Signal/noise ratio at this time (
S/N) was 55 dB, and very good signal writing and reading were possible.

(3) 60°C to check the durability of this optical recording medium.
After being left in an atmosphere of 95χRH for 4 months, signals were recorded in the unrecorded area using the same method as above, and the signals recorded before the durability test and the signals recorded after the durability test were played back. S of 53.54 dB each
/N was obtained, and the change in the durability test was sufficiently small.

(4) The shape of the focus of the signal recording section after the durability test was observed using a scanning electron microscope, and the pits recorded before and after the durability test had almost the same shape. In optical recording media whose recording layer is an inorganic thin film such as a Te-based film, there is almost no bulge at the edges of the pits, which is thought to occur due to the high thermal conductivity and causes noise, and the pit shape is very clean. It was confirmed that

Comparative Example 1 A carbon tetrachloride solution of a tetra-butyl-naphthalocyanine-vanadyl dye was used in place of the tetra-butyl-phthalo(1)/naphthalo(3) cyanine-vanadyl dye in Example 1, but substantially the same method as in Example 1 was used. When we attempted to create an optical recording medium with a recording layer consisting only of naphthalocyanine dye, we found that the solubility of tetra-butyl-naphthalocyanine vanadyl dye in carbon tetrachloride was lower than that of tetra-butyl-phthalo(1) and naphthalocyanine. (3) Compared to cyanine vanadyl dyes, the solubility was lower than that of 0.8% by weight or less. Therefore, tetra-butyl-naphthalocyanine vanadyl dye 0.
Using a carbon tetrachloride solution consisting of 5 parts by weight and 99.5 parts by weight of carbon tetrachloride, an optical recording medium having a recording layer consisting essentially only of naphthalocyanine dye was prepared in the same manner as in Example 1 except for the following: The film thickness, reflectance, and S/N were determined by recording/reproducing tests.The film thickness was 60n-, and the reflectance was also lower than that of Example 1, at 13%. The S/N result from the recording/playback test was extremely low at 33 dB.The S/N value required for normal optical recording media is said to be at least 45 dB, so in the case of the comparative example, it is not practical at all as a recording medium. It is clear that it cannot be used for

By comparing Example 1 and Comparative Example 1, it was shown that the present invention provides a recording layer with excellent durability and suitable for coating methods.

Example 2, Comparative Example 2 An example using a carbon tetrachloride solution of the phthalo/naphthalocyanine dye shown in Table 1 instead of the tetra-butyl-phthalo(1)/naphthalo(3) cyanine dye in Example 1. An optical recording medium having a recording layer consisting essentially only of phthalo-naphthalocyanine dye was prepared using the same method as in 1, and the S/N was determined by film thickness, reflectance, and recording/reproduction tests. In recording/playback tests, phthalo-naphthalocyanine with more benzene ring skeletons has a 780n
For phthalo-naphthalocyanine, which has a larger number of naphcrene ring skeletons, a semiconductor laser with an oscillation wavelength of 8 m is used.
Recording and reproduction were performed using a semiconductor laser having an oscillation wavelength of 30 nm. The results are summarized in Table 1.

As is clear from Table 1, S/N values of 50 to 55 dB were obtained in all of the examples of the present invention, and comparative examples consisting of a macrocyclic return ring consisting of only a benzene ring skeleton or only a naphthalene ring skeleton In contrast, it is shown that the reflectance and S/N ratio are improved. In other words, phthalocyanine dyes have a high reflectance but a low S/N value (and naphthalocyanine dyes have a sufficient S/N value but a low reflectance). This shows that by changing the ratio of the rings, it is possible to select an optimal recording layer in the wavelength range of 750 to 850 nm haze, which is convenient in practice.

Example 3, Comparative Example 3 Example 1 was prepared using a carbon tetrachloride solution consisting of the dye used in Example 1 and a resin binder of the type and amount shown in Table 2.
An optical recording medium was prepared and evaluated using the same method as described above. The thickness of the recording layer, the reflectance, and the S/N value obtained by recording and reproducing are
It is summarized in the table.

Table 2: Dimer acid polyamide B: Vinyl chloride feather % (weight 1) Vinyl acetate 17% copolymer Comparative example 3 (experiment numbers 12 to 14) in Table 2 could not be recorded. That is, although it was possible to control the focus of the laser beam during recording and the formation of bits was physically observed, it was not possible to extract a signal during reproduction (reading). This is because in the comparative example, the amount of resin binder is much larger than in the example of the present invention, so the initial reflectance is originally small at 9 to 10%, and even if pits are formed, the reflectance due to this is This seems to be due to the fact that the decrease in reflectance was slight, and therefore a change in reflectance that could be taken out as a signal was not obtained.

Comparative Example 4 After providing an aluminum reflective layer by vapor deposition on the acrylic resin plate used in Example 2, the same procedure as in Example 2 was carried out using the dye solutions of Experiment No. 1 and Experiment No. 7 on this reflective layer. and created an optical recording medium. The thicknesses of the resulting recording layers were 1100 nm and 140 nm, respectively, and the reflectances were 30% and 32%, respectively.

Using these optical recording media, signals were recorded and reproduced in the same manner as in Example 1 except that semiconductor laser light was irradiated from the recording layer side, and the S/N value was 28 dB, respectively.
When recording and reproducing the signal at a rotational speed of 450 rpm when recording the 0th order, which was very low at 22 dB, the S/N value increased, but the S/N value was 39 dB and 3, respectively.
It was still low at 5 dB.

From the above, when a reflective layer made of metal or the like is separately provided, the recording sensitivity decreases due to the high thermal conductivity of the reflective layer, making it impossible to record signals at high speed rotation, and even when recording at low speed rotation, the S/R is extremely small. It can be seen that only the N value can be obtained.

Comparative Example 5 In place of each asymmetric phthalo-naphthalocyanine dye used in Experiment No. 1.2.3 of Example 2, tetra-t
Using a carbon tetrachloride solution in which ert-butyl-phthalocyanine vanadyl dye and tetraoctylnaphthaloleanine vanadyl dye were mixed at a molar ratio of 3:1.2:2.1:3, the others were as in Example. Create an optical recording medium having a recording layer consisting essentially of a mixture of phthalocyanine dye and naphthalocyanine dye by the same method as in 2.
The film thickness and reflectance were measured, and signals were recorded and reproduced in the same manner as in Example 2. The results are shown in Table 3.

As is clear from the comparison with the results of Example 2, the absorption wavelength range of such a mixed recording layer is broader than that of Fukuro-naphthalocyanine, but the reflectance is 16%.
It can be seen that a sufficient S/N ratio cannot be obtained because the absorption is relatively small.

Example 5, Comparative Example 6 In place of the tetra-butyl-phthalo(1)/naphthalo(3) cyanine dye in Example 1, a phthalo-naphthalocyanine having a substituent -Y shown in Table 4 on the central metal An optical recording medium having a recording layer consisting essentially of phthalo-naphthalocyanine dye was prepared in the same manner as in Example 1 using a carbon tetrachloride solution of the dye, and film thickness, reflectance, and recording/reproduction tests revealed that S /N ratio was calculated using a semiconductor laser having the oscillation wavelength shown in Table 4, depending on the number of benzene ring skeletons and the number of naphthalene skeletons in the dye used. In addition, the results are shown in Table 4. As is clear from Table 4, the substituent -Y
Phthalo-naphthalocyanine, which is coordinated around a metal having

However, the naphthalocyanine compound shown in Experiment No. 24 has a maximum absorption wavelength of b<, around 860n*, which is probably why the reflectance was not sufficient and the S/N ratio was low. be done. On the other hand, experiment number 2
It can be seen that the compound of 0.21 has a spectrum shifted to the shorter wavelength side due to the inclusion of a benzene ring skeleton in the molecule, and exhibits very good compatibility with semiconductor lasers.

〔Effect of the invention〕

The optical recording medium of the present invention has sufficient reflectance because the recording layer itself has a novel macrocyclic mother ring structure, and does not require the provision of a reflective layer such as a thin metal film or a thin metal oxide film (although it is difficult to write signals). It is possible to perform readout, and a large reflectance allows a large S/N ratio to be obtained.Furthermore, the shape of the pit in the recording section has no raised edges, resulting in a large S/N ratio.
This confirms that N can be obtained and at the same time indicates the possibility of improving recording density.

The optical recording medium of the present invention has improved solubility in a solvent, can be easily mass-produced by a coating method, is stable against heat and humidity, and can be used for a long period of time.

The optical recording medium of the present invention can be compatible with semiconductor lasers having various oscillation wavelengths while maintaining a high S/N ratio.

[Brief explanation of the drawing]

Figure 1 shows the results of tetra-butyl-phthalo(1) and naphthalo(3) of the present invention when 830 na light was irradiated through the substrate.
) is a graph showing the film thickness dependence of reflectance when cyanine vanadyl dye is used as a recording film. Figure 2 (1) and (2) show the tetra-hebutyl-
In the phthalo-naphthalocyanine vanadyl dye, the number of benzene ring skeletons and naphthalene ring skeletons in the molecule is 1 = 3, such as tetra-hebutyl-phthalo (1), naphthalo (3) cyanine vanadyl (a), 2:2 tetra- Heptyl-phthalo (2), naphthalo (2) cyanine vanadyl (b
) and 3:1 Tetlerhep, Chiruftaro (3).
1 is a graph showing the wavelength dependence of the transmittance and reflectance of each recording layer of naphthalo(1) and cyanine vanadyl (C). FIGS. 3(1) and 3(2) are graphs showing the wavelength dependence of the transmittance and reflectance of a recording layer containing a 1:3 mixture of tetraheptyl-phthalocyanine vanadyl and tetra-heptylnaphthalocyanine vanadyl. Patent applicant: Mitsui Toatsu Kagaku Co., Ltd. Figure 1 Film thickness Figure 2 (1) Figure 2 (2) Wavelength (n, m) Figure 3 (1) ・ Figure 3 (2) Wavelength (nm)

Claims (3)

[Claims] (1) An optical recording medium having a recording layer made of an organic dye of a macrocyclic parent ring, wherein the macrocyclic parent ring has at least one benzene ring skeleton and at least one benzene ring skeleton in one unit of the macrocyclic parent ring. It contains a naphthalene ring skeleton (however, the benzene ring skeleton or the naphthalene ring skeleton may be unsubstituted or have a substituent -Z), and the macrocyclic mother ring center has two hydrogen atoms, a metal Or an optical recording medium characterized by being a novel asymmetric phthalo-naphthalocyanine dye molecule that coordinates a metal having a substituent. (2) The asymmetric phthalo-naphthalocyanine dye molecule has the following general formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, M represents two hydrogen atoms, a metal, or a metal oxide. , Y represents the substituent, n = 0, 1 or 2, L_1, L_2, L_3 and L_4 represent a benzene ring skeleton or naphthalene ring skeleton which is unsubstituted or has a substituent -Z, L_1, L_2 , L_3, and L_4 are benzene ring skeletons, and at least one is a naphthalene ring skeleton. (3) The optical recording medium according to claim 1, in which signals can be recorded and read by a light beam passing through a transparent substrate.