JPH0477675B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to an optical information recording medium having a thin film containing a dye. More specifically, the present invention relates to an optical information recording medium used in a method (so-called optical disk) in which information is reproduced by changes in reflected light recorded directly by a laser beam. Prior Art Conventionally, optical information recording media to which a dye thin film is applied as a recording layer are known (for example,
-16948). In other words, in this type of optical memory medium, a metal reflective film is provided between the dye thin film recording layer of the substrate, and a laser beam of a wavelength at which the light absorption rate of the recording layer is at its maximum is focused and irradiated from the recording layer side. It is used to record and reproduce information. However, in such optical information recording media, it is difficult to protect the dye recording layer, so errors in recording and reproducing information are likely to occur due to small dust adhering to the recording layer, and reflective optical information recording media In order to use it as a medium, a metal reflective film is required, which complicates the structure of the medium, and the recording/reproducing sensitivity is insufficient.
Furthermore, there is a problem that the information recording medium itself cannot withstand long-term storage. Purpose The present invention was made in view of the above problems, and its purpose is to provide an optical information recording medium that has high sensitivity (recording/reproduction) and S/N, and has high thermal stability in storage characteristics. It is in. Structure In order to achieve the above object, the present invention investigated various dyes that absorb near-infrared light, and as a result, a dye with excellent recording/reproducing characteristics and storage stability was discovered.
That is, the optical information recording medium of the present invention is a recording medium containing, on a substrate, a cyanine dye having one or two benzo[c,d]indole nuclei or a benzo[c,d]indole nucleus condensed with an aromatic ring. It has layers. The optical information recording medium of the present invention basically has only a recording layer containing the above-mentioned compound of the present invention provided on a substrate, but if necessary, an undercoat layer (for example, an ultraviolet curing resin) or a protective layer may be provided. Other layers such as can be provided. The recording material used in the recording layer of the present invention contains a cyanine dye having one or two benzo[c,d]indole nuclei or benzo[c,d]indole nuclei further condensed with an aromatic ring. Substituents such as alkyl, alkoxy, hydroxy, carboxyl, halogen, and allyl may be present on the indole nucleus. Further, when only one benzo[c,d]indole nucleus is present in the cyanine dye of the present invention, another nitrogen-containing aromatic nucleus may be present as the other nucleus constituting the cyanine dye. Examples of such nitrogen-containing aromatic nuclei include five-membered heterocycles or thiazole rings (e.g., thiazole, 4-methylthiazole,
5-methylthiazole, 4-phenylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4
-(2-thienyl)thiazole), benzothiazole ring (e.g., benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole,
6-chlorobenzothiazole, 7-chlorobenzothiazole, 4-methylbenzothiazole, 5-
Methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 6-bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzothiazole, 6- Methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, 4,5,6,7-tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5- Hydroxybenzothiazole, 6-hydroxybenzothiazole, 5,6-
methylenedioxybenzothiazole), naphthothiazole rings (e.g., α-naphthothiazole, β
Naphthothiazole, 5-methoxy-β-naphthothiazole, 5-ethoxy-β-naphthothiazole, 7-methoxy-α-naphthothiazole, 8-
methoxy-α-naphthothiazole), thieno[2,
3-e]benzothiazole ring (e.g., 5-methoxythieno[2,3-e]benzothiazole),
Oxazole rings (e.g. 4-methyloxazole, 5-methyloxazole, 4-ethyloxazole, 5-ethyloxazole, 4,5-dimethyloxazole, 4,5-diethyloxazole, 4-phenyloxazole, 5-phenyloxazole) , 4,5-dihephenyloxazole, ), benzoxazole rings (e.g., benzoxazole, 5-methylbenzoxazole, 6-
Methylbenzoxazole, 5-ethylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5-
Phenylbenzoxazole, 5-methoxybenzoxazole, 6-methoxybenzoxazole, 5-ethoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, 5-chlorobenzoxazole, 6-chlorobenzoxazole, 5-carboxy benzoxazole), naphthoxazole rings (e.g. naphtho[2,1-d]oxazole, naphtho[1,2-d]oxazole, naphtho[2,3-d]oxazole), selenazole rings (e.g. 4-methylselenium sol, 4-phenylselenazole), benzoselenazole ring (e.g., benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5
-Hydroxybenzoselenazole, 4,5,6,
7-terolahydrobenzoselenazole), naphthoselenazole ring (e.g. naphtho[2,1-d]
selenazole, naphtho[1,2-d]selenazole), thiazoline ring (e.g. thiazoline, 4-
methylthiazoline), 3,3-dialkylindole ring (e.g. 3,3-dimethylindole,
3,3,5-trimethylindole, 3,3,7
-trimethylindole), 3,3-dialkylbenzo[e]indole rings (e.g., 3,3-dialkylbenzo[e]indole); and six-membered heterocycles, i.e., quinoline rings (e.g., quinoline,
3-methylquinoline, 5-methylquinoline, 7-
Methylquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline), isoquinoline ring (e.g. isoquinoline, 3, 4-dihydroisoquinoline), pyridine rings (e.g. pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 2,3-dimethylpyridine, 2,4-dimesylpyridine, 2,5-dimethylpyridine, 2,6-dimethylpyridine, 3,
4-dimethylpyridine, 3,5-dimethylpyridine, 2-chloropyridine, 3-chloropyridine,
4-chloropyridine, 2-hydroxypyridine,
3-hydroxypyridine, 4-hydroxypyridine, 2-phenylpyridine, 3-phenylpyridine, 4-phenylpyridine). Examples of cyanine dyes used in the present invention include the following. 1-methyl-2-[3-(1-methyl-[c,d]
benzo-2-indolinylidene)-1-propenyl]-[c,d]benzoylidolium perchlorate, 1-ethyl-2-[3-(1-ethyl-[c,d]
Benzo-2-indolinylidene)-1-propenyl]-[c,d]benzoindolium perchlorate, 1-ethyl-2-[3-(1-methyl-[c,d]
benzo-2-indolinylidene)-1-propenyl]-[c,d]benzoylidolium iodide, 1-methyl-2-[3-(1-methyl-6-chloro-[c,d]benzo- 2-indolinylidene)-
1-propenyl]-6-chloro-[c,d]benzoindolium chloride, 1-methyl-2-[5-(3-methyl-6-methoxy)-2-thiazolinylidene)-1,3-pentadienyl]- [c,d]benzoindolium perchlorate, 1-methyl-2-[3-(1-methyl-3,3-
dimethyl-2-indolinylidene)-1-propenyl]-[c,d]benzoindolium paratoluenesulfonate, 1-ethyl-2-[3-(1-ethyl-[1,2,
3-c,d]naphthoindolinylidene)-1-propenyl]-[1,2,3-c,d]-naphthoindolium perchlorate, 1-octyl-2-[3-(1-octyl-[ 3,
2,1-c,d]naphthoindolinylidene)-1
-propenyl]-[3,2,1-c,d]naphthoindolium bromide, 1-methyl-2-[3-(1-methyl-[(c,
d), g] dibenzoindolinylidene)-1-propenyl]-[(c, d), g] dibenzoindolium methyl sulfate, 1-ethyl-2-[3-(1-ethyl-2-quinolinylidene) )-1-propenyl]-[c,d]benzoindolium perchlorate 1-n-octyl-2-[3-(1-n-octyl-6-methoxy-[c,d]benzo-2-indolini lidene)-1-propenyl]-6-methoxy-[c,d]benzoindolium chloride, 1-methyl-2-[3-(3-methyl-2-oxazolinylidene)-1-propenyl]-[ c, d]
Benzoindolium perchlorate, 1-ethyl-2-[3-(1-ethyl-5-methyl-[c,d]benzo-2-indolinylidene)-
1-propenyl]-5-methyl-[c,d]benzoindolium perchlorate, 1-methyl-2-[3-(1-methyl-[(c,
d), f] dibenzo-2-indolinylidene)-1
-propenyl]-[(c,d),f]dibenzoindolium bromide, 1-methyl-2-[3-(3-methyl-4,5-
Diphenyl-2-thiazolinylidene)-1-propenyl]-[(c,d),f]dibenzoindolium chloride, 1-methyl-2-[3-methyl-2-quinolinylidene)-propenyl]-[c,d] Benzoindolium chloride, 1-methyl-2-[3-(1-methyl-6-acetyl-[c,d]benzo-2-indolinylidene)
-1-propenyl]-6-acetyl-[c,d]benzoindolium perchlorate, 1-ethyl-2-[3-methyl-6-phenyl-[c,d]benzo-2-indolinylidene)- 1
-propenyl]-6-phenyl-[c,d]benzoindolium perchlorate, 1-methyl-2-[2-methyl-3-(1-methyl-[c,d]benzo-2-indolinylidene)
1-propenyl]-[c,d]benzoindolium bromide. Further, when forming the recording layer of the present invention, a binder can be mixed with the cyanine dye. The mixing ratio of the cyanine dye to the binder is 10 to 90% by weight, preferably 30 to 90%.
As the binder, for example, nitrocellulose, acrylic resin, urethane resin, butyral resin, polycarbonate resin, etc. can be used. The substrate materials used in the present invention are known to those skilled in the art and can be either transparent or opaque to the laser light used. However, when writing and recording is performed using a laser beam from the substrate side, it must be transparent to the writing laser beam. on the other hand,
When writing and recording is performed from the side opposite to the substrate, that is, from the surface of the recording layer, it is not necessary to be transparent to the writing laser beam. However, when read and reproduced using transmitted light, it must be transparent to the read laser beam. When read and reproduced using reflected light, it may be transparent or opaque to the read laser beam. The substrate material may be a commonly used recording material support such as glass, quartz, ceramic, plastic, paper, plate-shaped or foil-shaped metal. Further, the substrate may be provided with a guide groove formed with unevenness, if necessary. Formation of the recording layer in the present invention mainly depends on a coating method, but can be carried out using vapor deposition, and the thickness thereof is preferably about 1000 Å or less. When using a coating method, examples of organic solvents include acetone,
1,2-dichloroethane and the like can be used. Application is carried out by conventional coating methods such as spraying, roller coating, dipping and spinning. Next, the configuration and recording/reproducing method of the optical information recording medium of the present invention will be explained with reference to the screen. 1st
As shown in the figure, an optical information recording medium 1 basically comprises a substrate 2 and a recording layer 3 containing the cyanine dye of the present invention. Recording and reproduction are performed by condensing the laser beam 4 onto the recording layer 3 to a size of 1 to 2 μm using a condensing lens 5. The recording/reproducing beam may be irradiated from the side of the recording layer 3, but if the substrate is transparent, irradiation from the side of the substrate 2 has the advantage that it is less affected by dust. Information is recorded by forming pits in the recording layer by the thermal action of laser light, and information is reproduced by detecting the difference in reflected light from pit-formed areas and non-pit-formed areas. It will be done.
Although not shown as another embodiment, it is also possible to arrange two recording media 1 having the same configuration with their recording layers 3 facing each other (so-called air sandwich method), and in such a case Since the recording layer 3 is isolated from the outside air and can be protected from dust, scratches, and contact with harmful gases, storage stability is significantly improved. At this time, since the recording layer 3 is protected by the substrate 2, the recorded information is not damaged by physical or chemical effects. The laser beam applied to the information recording medium of the present invention must be selected depending on the absorption wavelength of the dye compound used, but relatively inexpensive He--Ne lasers or semiconductor lasers are preferred. EXAMPLES The present invention will be further explained below using Examples together with Comparative Examples, but the present invention is not limited thereto. Example 1 The above 10 compounds and 2 comparative compounds were each dissolved in dichloroethane to form a 1% by weight solution. Spin coat each solution onto an acrylic plate coated with ultraviolet curing resin, dry it, and measure the thickness.
A recording layer of 480 Å was obtained. These recording media use a semiconductor laser with a wavelength of 790 nm, with an irradiation surface power of 3.7 mW and a beam diameter of 1.54 μm.
A 0.7MHz signal was recorded at a linear velocity of 1.2m/sec. When this recording section was irradiated with a weak laser beam and the signal was reproduced, a signal with a C/N ratio as shown in Table 1 was obtained (IF band width: 30 KHz). When these recording media were left in an oven at 70° C. for 30 days and the signals were reproduced again, C/N signals as shown in Table 1 were obtained. Furthermore, an attempt was made to record a new signal in the unrecorded area, but Comparative Compound 1 had faded and could not be recorded.

【table】

[Table] Comparison 2 No sensitivity − −
Example 2 2% by weight of compound 1 using acetone as solvent
A coating solution consisting of 4% by weight of nitrocellulose was prepared, and this was spin-coated onto an acrylic plate. After drying, a recording layer of 400 Å was obtained. In addition, Example 1
When I recorded and played back the signal in the same way,
A C/N of 46 dB was obtained. When this was left at 70°C for 30 days and then played again, a C/N of 46 dB was obtained. It was also possible to record new signals in unrecorded areas. Example 3 Using 1,2-dichloroethane as a solvent 1.5
A coating solution consisting of 6% by weight of compound 6 and 3% by weight of acrylic resin was prepared, and this was spin-coated onto an acrylic plate. After drying, a recording layer of 450 Å was obtained. When a signal was recorded and reproduced on this in the same manner as in Example 1, a C/N of 45 dB was obtained. Heat this to 70℃ for 30
When I played it again after leaving it for a day, a C/N of 45 dB was obtained. It was also possible to record new signals in unrecorded areas. Example 4 The coating solution used in Example 3 was spin-coated onto a glass plate provided with guide grooves made of ultraviolet curable resin. After drying, a recording layer of 450 Å was obtained. When a signal was recorded and reproduced on this in the same manner as in Example 1, a C/N of 46 dB was obtained. After leaving this at 70℃ for 30 days,
When I played it again, a C/N of 46 dB was obtained.
It was also possible to record new signals in unrecorded areas. Effects The optical information recording medium of the present invention configured as described above can exhibit high thermal stability and storage stability.

[Brief explanation of the drawing]

The drawings are schematic diagrams showing the basic structure and recording/reproducing method of the optical information recording medium of the present invention. DESCRIPTION OF SYMBOLS 1... Information recording medium, 2... Substrate, 3... Recording layer, 4... Laser beam, 5... Condensing lens.

Claims (1)

[Scope of Claims] 1. Having a recording layer on a substrate containing a cyanine dye having one or two benzo[c,d]indole nuclei or benzo[c,d]indole nuclei further condensed with an aromatic ring. An optical information recording medium characterized by: