JPH0611586B2 - Optical recording medium - Google Patents

Description

The present invention relates to an optical recording medium containing an indanthrene derivative in a recording layer. More specifically, the recording layer is perforated by irradiation with a high-energy beam to perform recording and read recorded information. The present invention relates to an improvement of an optical recording medium that changes the amount of reflected light due to irradiation with a low output energy beam.

Conventionally, many optical recording media for laser writing are known. Typical examples thereof include a substrate on which a metal, a semimetal, or a nonmetal is vapor-deposited or a substrate on which a dye is vapor-deposited or applied.

However, the method of vapor-depositing metal or the like has a problem in that productivity is poor and the oxidation resistance of the recording layer is poor. Further, most of the dye-coated or vapor-deposited materials do not have absorption in the wavelength range of the semiconductor laser used, and even if they have absorption, the weather resistance is poor.

Therefore, the present inventors have previously proposed a method of forming a metal reflection layer by a coating method and combining it with a light absorption layer, a method of using a dye coating film as a recording layer, and the like. The medium has not been sufficiently satisfactory in that it has low sensitivity or low stability to a semiconductor laser.

In view of the above problems, the present inventors have made further studies on dyes, and as a result, have succeeded in finding a dye having absorption in the near infrared region and high stability. However, the present invention is based on such findings, and an object of the present invention is to provide a recording medium for a semiconductor laser with high sensitivity and stability by using an indanthrene derivative in the recording layer. is there.

That is, according to the present invention, in the optical recording medium in which recording is performed by forming a hole in the recording layer by irradiation of a high energy beam and reading of recorded information is performed by a change in reflected light amount by irradiation of a low output energy beam, The optical recording medium is essentially composed of a substrate and a recording layer, and the recording layer is composed of an indanthrene derivative represented by the following general formula [I] alone or in combination with other components. An optical recording medium is provided.

(In the formula, X ₁ , X ₂ , X ₃ and X ₄ each represent hydrogen, an alkyl group, a hydroxyl group, a nitro group, an amino group, a cyano group or a halogen, and X ₅ represents hydrogen, —S—Ar ₁ or Represents —NH—Ar ₁ , Z is hydrogen, —NH—Ar ₁ —
Represents S-Ar ₁ . Ar ₁ represents hydrogen, a phenyl group or a naphthyl group, and the phenyl group and the naphthyl group are substituted by an alkyl group, an alkoxy group, an amino group, an alkylcarbonyl group, a methylthio group, a halogen, a phenylcarbonyl group or a sulfo group. Good. The indanthrene derivative used in the present invention includes compounds having various substituents on the indanthrene skeleton, and specifically, it can be represented by the above structural formula [I].

The compound having the indanthrene skeleton represented by the general formula [I] has the maximum absorption wavelength around 800 nm, and is therefore optimum as a material for a semiconductor laser.

Examples of the indanthrene derivative represented by the above structural formula [I] are shown below.

8,17-bis- (4-methoxyphenylamine) -indanthrene, 8,17-bis (4-methylphenylamino) indanthrene, 8,17-bis (4-chlorophenylamino) indanthrene, 2 , 3,11,12-Tetranitro-8,17-bisanilinoindanthrene, 6,15-bis (2-methylthiophenylamino) indanthrene, 6,15-bis- (3,5-dimethoxyphenylamino) Indanthrene, 8,17-bis (anilino) indanthrene, 8,17-bis (sodium phenylamino 4-phenylsulfonate) indanthrene, 8,17-bisphenylthioindanthrene, 8,17- Bis (2-methoxyphenylamino) indanthrene, 8,17-bis (3-methoxyphenylamino) indanthrene, 8,17-bis (2-methylphenylamino) indanthrene, 8,17-bis ( 3-Methylphenylamino) indanthrene, 8,17-bis (2-chlorophenylamino) indanthrene, 8,17-bis (3- Lolophenylamino) indanthrene, 8,17-bis (2-methylthiophenylamino) indanthrene, 8,17-bis (3-methylthiophenylamino) indanthrene, 8,17-bis (4-methylthiophenyl) Amino) indanthrene, 8,17-bis (4-phenylthiophenylamino) indanthrene, 8,17-bis (2,5-dimethoxyphenylamino) indanthrene, 8,17-bis (4-methyl -2-chlorophenylamino) indanthrene, 8,17-
Bis (2,4,6-trimethylphenylamino) indanthrene, 8,17-bis (1-naphthylamino) indanthrene, 8,1
7-bis (2-naphthylamino) indanthrene, 8,17-bis
(2-Methoxyphenylthio) indanthrene, 8,17-bis
(4-Phenylphenylamino) indanthrene, 8,17-bis (sodium 2-methoxy-4-sulfonate phenylamino) indanthrene, 8,17-bis (3-methoxy-4-sodium phenylphenylamine ) Indanthrene, 8,17-bis (sodium phenylamino-4-methoxy-2-phenylphenyl) indanthrene, 8,17-bis (sodium phenylamino-2-phenyl-4-sulfonate) phenylidene, 8 , 17-bis
(3-Methyl-4-sulfonate sodium phenylamino) indanthrene, 8,17-bis (4-methyl-2-sulfonate sodium phenylamino) indanthrene, 8,17-bis (2-
Methylthio-4-sulfonic acid sodium phenylamino) indanthrene, 8,17-bis (3-Methylthio-4-sulfonic acid sodium phenylamino) indanthrene, 8,17-bis
(4-Methylthio-2-sulfonate sodium phenylamino) indanthrene, 8,17-bis [4- (sodium 4-phenylphenylphenylthio) phenylamino] indanthrene, 8,17-bis (2,5 -Sodium dimethoxy-4-sulfonate phenylamino) indanthrene, 8,17-bis [1- (4-
Sodium sulfonate naphthyl) amino] indanthrene, 8,17-bis [2- (sodium naphthyl 4-sulfonate)
Amino] indanthrene, 8,17-bis (4-hydroxyphenylamino) indanthrene, 8,17-bis (3-hydroxyphenylamino) indanthrene, 8,17-bis (2-hydroxyphenylamino) Indanthrene, 6,15-bis (2-chlorophenylamino) indanthrene, 6,15-bis (3-chlorophenylamino) indanthrene, 6,15-bis (4-chlorophenylamino) indanthrene, 6 , 15-Bis (2-methylphenylamino) indanthrene, 6,15-bis (3-methylphenylamino) indanthrene, 6,15-bis (4-methylphenylamino) indanthrene, 6,15 -Bis (4-chloro-2-methylphenylamino) indanthrene, 6,15-
Bis [3- (methylthio) phenylamino] indanthrene, 6,15-bis [2- (methylthio) phenylamino] indanthrene, 6,15-bis (2-methoxyphenylamino) indanthrene, 6, 15-bis (3-methoxyphenylamine)
Indanthrene, 6,15-bis (4-methoxyphenylamine) indanthrene, 6,15-bis (4-ethoxyphenylamine) indanthrene, 6,15-bis (1-naphthylamino) indanthrene , 6,15-bis (2-naphthylamino) indanthrene, 6,15-bis [4- (phenylthio) phenylamino] indanthrene, 6,15-bis (2-chloro-4-sulfonic acid sodium phenyl Amino) indanthrene, 6,15-bis (sodium 3-chloro-4-sulfonate phenylamino)
Indanthrene, 6,15-bis (sodium phenylamino 4-chloro-2-sulfonate) Indanthrene, 6,15-bis (2
-Sodium methyl-4-sulfonate-phenylamino) indanthrene, 6,15-bis (sodium 3-methyl-4-sulfonate-phenylamino) indanthrene, 6,15-bis (4-methyl-3) -Sodium sulfonate-phenylamino) indanthrene, 6,15-bis (sodium 2-methoxy-4-sulfonate-phenylamino) indanthrene, 6,15-bis (sodium 3-methoxy-4-sulfonate) -Phenylamino) indanthrene, 6,15-bis (sodium 4-methoxy-2-sulfonate-phenylamino) indanthrene.

The optical recording medium of the present invention basically comprises a substrate and a recording layer, but an undercoat layer may be provided on the substrate and a protective layer may be provided on the recording layer according to the purpose. .

Any known substrate can be used as the substrate in the present invention as long as it is transparent to the laser used. Typical examples thereof include glass or plastic, and as the plastic, acrylic, polycarbonate, polysulfone, polyimide, or the like is used. An undercoat layer can be appropriately provided on the glass or plastic substrate.

The recording layer in the present invention is roughly classified into one composed of the indanthrene derivative alone or a combination thereof with other components per se, or one composed of a reflective layer and a light absorbing layer containing the indanthrene derivative. To be done. The recording layer composed of the indanthrene derivative alone or a combination of the indanthrene derivative itself and other components can be used by dissolving the indanthrene derivative in a solvent and applying it, by vapor deposition on a substrate, or by mixing with a resin solution. Coating method,
It is formed by a co-evaporation method with another dye, a method of applying a mixed solution with another dye, a method of dissolving the dye together with another dye in a resin solution and applying the solution.

Known resins such as PVA, PVP, polyvinyl butyral, and polycarbonate are used as the resin, and the amount of the indanthrene derivative with respect to the resin is preferably 0.01 or more in weight ratio.

The film thickness is in the range of 0.01 to 1 μm, preferably 0.05 to 0.5 μm.

In addition, the recording layer composed of the reflective layer and the light absorbing layer containing the indanthrene derivative is first provided with the reflective layer, and then the indanthrene derivative alone or in the same manner as described above on the reflective layer. It is formed by providing a light absorbing layer composed of a combination thereof with other components. The reflective layer is, for example, a water-soluble resin (PVP, PVA, etc.)
The metal salt or metal complex salt is dissolved in, and a solution containing a reducing agent is applied to the substrate, and the temperature is 50 ° C to 150 ° C, preferably 60 ° C.
It is formed by heating and drying at -100 ° C.

The weight ratio of metal salt or metal complex salt to resin is 0.
It is 1 to 10, preferably 0.5 to 1.5.

As the metal salt or metal complex salt, silver nitrate, silver cyanide potassium, potassium gold cyanide, silver ammine complex, silver cyan complex, gold salt or gold cyan complex can be used. As a reducing agent, formalin, tartaric acid, tartrate, reducing sugar, hypophosphite, sodium borohydride, dimethylamine borane, etc. can be used. The reducing agent is a metal salt or a metal complex salt 1
It can be used in an amount of 0.2 to 10 mol, preferably 0.5 to 4 mol, per mol.

Further, the reflective layer can be formed by a vapor deposition method or a plating method in addition to the above method.

Information is recorded by irradiating a spot of a high-energy beam such as a laser from the side of the substrate, and the absorbed heat causes a hole in the recording layer to be recorded. Of course, recording from the recording layer side is also possible. Since the recording surface is on the substrate side, no protective layer is required.

Information can be read by irradiating a low-power laser beam and detecting the change in the amount of reflected light.

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited thereto.

Example 1 An acrylic plate was used with 2000 of 8,17-bisanilinoindanthrene.
A recording medium was prepared by vapor deposition to a thickness of Å. The optical characteristics of this recording medium are shown in FIG.

This recording medium was measured by the device shown in FIG.
Irradiation surface energy of 4 mW using a semiconductor laser of 790 nm
When information was recorded from the substrate side with a beam diameter of 1.6 μm, a spot with a diameter of 1.1 μm was formed by irradiation for 0.2 μs (0.8 nJ / Pit).

This recording medium also showed the same characteristics after being stored in room light at 40 ° C and humidity of 90% for 1 month.

Example 2 8,17-bis (4-methylphenylamino) indanthrene
0.5 g Nitrobenzene 10 ml A solution having the above composition was applied on a glass substrate by a spin coating method, and dried at 150 ° C. under reduced pressure to prepare a recording medium. The reflectance and absorptance at 800 nm of this recording medium were 12% and 77%, respectively.

Information was recorded on the recording medium thus obtained in the same manner as in Example 1. Irradiation for 0.2 μsec (0.8 n
J / Pit) formed a spot with a diameter of 1.2μ.

Further, this recording medium showed similar characteristics even after being stored for 1 month at 90% in room light and at 40 ° C. and humidity.

Example 3 Polyvinyl alcohol 1 g Water 15 g A solution having the above composition was spin-coated on an acrylic plate to give a thickness.
A 1.2 μm undercoat layer was obtained. Further, on this, 6,15-bis (4-methylthiophenylamino) indanthrene 0.5 g chlorobenzene 10 ml A solution having the above composition was spin-coated and dried at 100 ° C. under reduced pressure to obtain a recording layer having a thickness of 0.15 μm. It was

The reflectance and absorptance at 800 nm of this recording medium were 11% and 71%, respectively.

Information was recorded on the recording medium thus obtained in the same manner as in Example 1. As a result, irradiation for 0.15 μsec (0.6 nJ
/ Pit) formed a spot with a diameter of 1.1 μm.

Further, this recording medium showed the same characteristics even after being stored for 1 month at 90% in room light and at 40 ° C wet.

Example 4 Polyvinyl alcohol 0.5 g Water 10 g A solution having the above composition was applied onto the recording medium formed in Example 1 by a spin coating method and dried at room temperature to obtain a protective layer having a thickness of 0.6 μm. .

Information was recorded on the recording medium thus obtained in the same manner as in Example 1. As a result, 0.35 μsec irradiation (1.4 nJ
/ Pit) formed a spot with a diameter of 1.2 μm.

Example 5 Polyvinyl butyral 0.5 g Isopropanol 10 g A solution having the above composition was spin coated on the recording medium prepared in Example 3 and dried at 60 ° C. to a thickness.
A protective layer of 0.5 μm was obtained.

Information was recorded on the recording medium thus obtained in the same manner as in Example 1, and it was irradiated with 0.3 μsec (1.2 nJ /
Pit) formed a spot with a diameter of 1.0 μm.

Example 6 8,17-bis (sodium phenylamino 4-sulfonate) indanthrene 1 g polyvinyl butyral 1 g water 10 g A solution having the above composition was spin-coated on an acrylic plate to give a thickness.
A recording layer of 0.3 μm was obtained. The reflectance and absorptance at 800 nm were 12% and 68%.

When information was recorded on the recording medium thus obtained in the same manner as in Example 1, a spot having a diameter of 1.2 μm was formed by irradiation for 0.4 μsec (1.6 nJ / Pit).

Examples 7 to 13 When the compound shown in Table 1 below was used in place of the 8,17-bisanilinoindanthrene used in Example 1, Example 1 was repeated, and the properties shown in Table 1 were obtained. Was obtained (Examples 7 to 10).

In addition, the characteristics shown in Table 1 were obtained when Example 2 was repeated by using the coating solutions shown in Table 1 below instead of the coating solutions used in Example 1 (Examples 11 to 13). .

Example 14 Polyvinyl alcohol 1 g Water 9 g Potassium chloroaurate 1 g Formalin 0.1 ml A solution having the above composition was applied to an acrylic plate by a dipping method, heated at 80 ° C. for 10 minutes and washed with water to obtain a gold particle reflection layer. It was Furthermore, polyvinyl butyral 1g Isopropyl alcohol 2ml Toluene 5ml 8,17-Bis (4-methoxyphenylamino) -indanthrene
1 g A solution having the above composition was applied and dried to obtain a light absorbing layer. The reflectance and absorptance at 800 nm were 30% and 61%, respectively. Recording was performed on this recording medium with a semiconductor laser in the same manner as in Example 13.
Irradiation (3.2 nJ / Pit) for 8 μsec formed a spot with a diameter of 0.9 μm.

The same characteristics were obtained even after storing this recording medium for 1 month at 40 ° C. and 90% humidity in room light.

Example 15 Polyvinyl alcohol 1 g Water 9 g Silver nitrate 2 g 28% Ammonia water 3 ml Formamide 0.5 ml Glucose 1.5 g A solution having the above composition was applied to an acrylic plate by a spin coating method, heated at 60 ° C. for 5 minutes and washed with water to obtain silver particles. A reflective layer was obtained. Further, on this, 8,17-bisanilinoindanthrene was vapor-deposited to obtain a light absorption layer having a thickness of 1500 Å. The optical characteristics of this recording medium are shown in FIG.

When information was recorded on the recording medium thus obtained in the same manner as in Example 13, a spot having a diameter of 1.2 μm was formed by irradiation (2.0 nJ / Pit) for 0.5 μsec.

The same characteristics were obtained even after storing this recording medium for 1 month at 40 ° C. and 90% humidity in room light.

Example 16 Tin was deposited on an acrylic plate to a thickness of 500Å to obtain a metal reflective layer. A solution having the composition of 8,17-bis (sodium 2-methyl-4-sulfonate phenylamino) indanthrene 1g water 5g was spin-coated on this to obtain a light absorption layer having a thickness of 0.2 μm. The reflectance and absorptance at 800 nm were 35% and 58%.

Using a semiconductor laser with a wavelength of 790 nm on the recording medium thus obtained, the irradiation surface energy was 4 mW and the beam diameter was 1.6 μm.
When information of 0.5MHz was recorded from the substrate side with m, 0.8μ
A second spot (3.2 nJ / Pit) formed a spot with a diameter of 1.1 μm.

This recording medium was stored in the same manner as in Example 15, but the characteristics did not change.

Example 17 Silver nitrate 17.5 g Water 600 ml Sodium hydroxide 10 g Polyvinyl alcohol 5 g Formamide 20 ml Ammonia water was added to the solution having the above composition until the solution became transparent to give a solution A. Glucose 45 g Tartaric acid 4 g Alcohol 100 ml Water 100 ml A solution having the above composition was mixed with this solution A and the acrylic plate was immersed for 10 minutes to obtain a silver particle reflection layer.

Furthermore, 8,17-bis (sodium 2-methyl-4-sulfonate phenylamino) indanthrene 1g polyvinyl alcohol 1g water 10g A solution having the above composition was spin-coated and dried at 60 ° C.
A light absorbing layer having a thickness of 0.4 μm was obtained. The reflectance and absorptance at 800 nm were 35% and 63%.

When information was recorded on this recording medium in the same manner as in Example 16, a spot having a diameter of 1.0 μm was formed by irradiation for 0.7 μsec (2.8 nJ / Pit).

This recording medium was stored in room light at 40 ° C. and a humidity of 90% for one month, but the characteristics did not change.

Example 18 A silver particle reflective layer was obtained in the same manner as in Example 15 on an acrylic plate on which a polyvinyl butyral resin was applied in advance to a thickness of 2 μm. Further, polyvinyl alcohol 1g water 10g 8,17-bis (sodium phenylamino 4-phenylsulfonate) indanthrene 0.5g was coated with a solution having the above composition and dried at 60 ° C to obtain a light absorbing layer. . Polycarbonate resin 1 g Dichloroethane 20 ml A solution of the above composition was applied on top of this and dried at 60 ° C to a thickness of
The protective layer has a thickness of 0.9 μm.

When information was recorded on the recording medium thus obtained in the same manner as in Example 16, the diameter was obtained by irradiation for 0.7 μsec (2.8 nJ / Pit).
A 1.1 μm spot was formed.

Example 19 Polyvinyl alcohol 1g Water 10g 8,17-Bis (sodium phenylamino 4-phenylphenyl) indanthrene 0.5g CI Acid Blue 83 (CI42660) 0.7 on the silver particle reflective film prepared in Example 15. g A solution having the above composition was spin-coated and dried at 60 ° C. to obtain a light absorbing layer.

The reflectance and absorptance at 800 nm were 32% and 61%, respectively. The reflectance and absorptance at 630 nm were 27% and 65%, respectively.

When information was recorded on the recording medium thus obtained in the same manner as in Example 16, a diameter of 1.μm was obtained by irradiation for 0.7 μsec (2.8 nJ / Pit).
A spot of 0 μm was formed.

In addition, using a He-Ne laser for this recording medium, we recorded 0.5 MHz information at an irradiation surface energy of 3 mW and a beam diameter of 1.6 μm, and a diameter of 1.2 μ was obtained by irradiation for 0.8 μs (2.4 nJ / Pit).
m spots were formed.

Examples 20 to 21 The recording materials shown in Table 2 below were used in place of the 8,17-bisanilinoindanthrene used in Example 15 and Example 15 was used.
When repeatedly carried out, the characteristics shown in Table 2 were obtained.

Example 22 The silver particle reflective layer obtained in the same manner as in Example 15 was added with 6,15-
Bis (phenylthio) indanthrene was vapor-deposited to a thickness of 100 nm to obtain a light absorbing layer.

The reflectance and absorptance at 800 nm were 27% and 66%, respectively.

On the recording medium thus obtained, when information was recorded in the same manner as in Example 16, irradiation for 0.5 μsec (2.0 nJ / Pit)
A spot with a diameter of 0.9 μm was formed.

Further, this recording medium was stored in room light at 40 ° C. and humidity of 90% for one month, but the same characteristics were obtained.

Example 23 A silver particle reflection layer obtained in the same manner as in Example 15 was coated with a solution having a composition of 6,15-bis (sodium phenylthiosulfonate 4-phenylthio) indanthrene (1 g) and water (9 g) by a dipping method. It was dried to obtain a light absorbing layer.

The reflectance and the absorptance at 800 nm were 29% and 59%, respectively.

On the recording medium thus obtained, when information was recorded in the same manner as in Example 16, irradiation for 0.5 μsec (2.0 nJ / Pit)
, A spot with a diameter of 1.0 μm was formed.

In addition, no change in properties was observed due to storage.

For comparison, as a recording material, a cyanine dye 2-
When [7- (3-ethyl-2-benzothiazolinylidene) -1,3,5-heptatrienyl] -3-ethylbenzothiazolium chloride was used, the initial characteristics were the same as in Example 7. However, when it was stored for 1 month under the condition of 40 ° C and 90% in room light, the absorption rate decreased to 23% and recording could not be performed.

With respect to the other indanthrene derivatives used in the present invention, the same characteristics were obtained when an optical recording medium was prepared and information was recorded in the same manner as the method described in the above example.

The optical recording medium of the present invention constructed as described above has absorption in the wavelength region of the semiconductor laser, is highly stable, and has an excellent effect of storing information for a long period of time.

[Brief description of drawings]

1 and 2 show an optical recording medium of the present invention (Example 1).
And the optical characteristics of Example 15) (in the figure, the solid line indicates the reflectance and the dashed-dotted line indicates the absorptance), and FIG. 3 shows a schematic view of a recording / reproducing apparatus used for carrying out the present invention. 1 ... Substrate, 2 ... Recording layer, 3 ... Semiconductor laser, 4
...... Coupling lens, 5 …… Beam splitter,
6 ... λ / 4 plate, 7 ... condenser lens, 8 ... photodiode, 9 ... detection signal, 10 ... turntable.

Front Page Continuation (72) Inventor Yu Ueda 1-3-6 Nakamagome, Ota-ku, Tokyo Reco Ltd. (72) Noriko Obuchi 1-3-6 Nakamagome, Ota-ku, Tokyo Rico Co., Ltd. -In (56) Reference JP-A-50-122936 (JP, A) JP-A-51-83529 (JP, A) JP-A-55-161690 (JP, A)

Claims (1)

[Claims] 1. An optical recording medium in which recording is performed by forming a hole in a recording layer by irradiation of a high energy beam and reading of recorded information is performed by changing a reflected light amount by irradiation of a low output energy beam. For optical recording, which essentially comprises a substrate and a recording layer, and the recording layer is composed of an indanthrene derivative represented by the following general formula [I] alone or in combination with other components. Medium. (In the formula, X ₁ , X ₂ , X ₃ and X ₄ each represent hydrogen, an alkyl group, a hydroxyl group, a nitro group, an amino group, a cyano group or a halogen, and X ₅ represents hydrogen, —S—Ar ₁ or represents -NH-Ar _1, Z is hydrogen, .Ar ₁ representing the -NH-Ar ₁ or -S-Ar ₁ represents hydrogen, a phenyl group or a naphthyl group, and said phenyl and naphthyl groups are alkyl groups, It may be substituted with an alkoxy group, amino group, alkylcarbonyl group, methylthio group, halogen, phenylcarbonyl group or sulfo group.)