JPH10244752A - Optical recording medium - Google Patents

Abstract

(57) [Problem] To provide an optical recording medium having an organic dye layer suitable for recording and reproduction with a laser beam of 620 to 690 nm as a recording layer. SOLUTION: The dye of the following formula is used as a dye of an optical recording layer. Embedded image R ¹ and R ² represent an optionally substituted alkyl group, alkenyl group, cycloalkyl group or aryl group.
¹ and R ² may combine to form a heterocyclic ring, or R ¹ and R ³ may combine to form a heterocyclic ring.
R ³ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl or alkoxy group when R ³ does not form a heterocyclic ring with R ¹ .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical recording medium recordable by laser light.

[0002]

2. Description of the Related Art In recent years, attention has been paid to shortening the oscillation wavelength of laser light for high-density recording.
There is a demand for an optical recording medium capable of recording and reproducing with a laser beam having a shorter wavelength. Optical recording media proposed in such a situation include a magneto-optical recording medium, a phase-change recording medium, a chalcogen oxide-based recording medium, an organic dye-based recording medium, and the like. Among these, the organic dye-based recording medium is considered to have an advantage in that it is inexpensive and easy to manufacture.

[0003] By the way, as an organic dye-based optical recording medium, a type in which a highly reflective metal layer is laminated on a thin organic dye layer as a recordable compact disc is widely known. The current proposals have poor recording sensitivity and are disadvantageous for recording at a high linear velocity. In addition, since the substrate is deformed in addition to the dye at the time of recording, the bit length reproduction method has a problem that the bit length varies greatly and the jitter increases.

On the other hand, a great deal of research has been conducted on a recording method using a single layer of organic dye, including a method of recording / reproducing light incident on a film surface, and a part of the method has been put into practical use as an optical recording medium for 780 nm. Have been. However, for short wavelength applications, Japanese Patent Application Laid-Open Nos.
Although various proposals have been made, such as JP-A-238036 and JP-A-5-38878, the light resistance, environmental resistance, etc. are still insufficient, and any problems inherent in short wavelength applications are solved. It is not at present.

[0005]

The conventional organic dye-based optical recording medium has a problem that rim formation caused by recording is disadvantageous for short wavelength applications, that is, high density recording by short bit recording. Was. Also, it was difficult to obtain sufficient recording density and recording characteristics in high linear velocity recording of 10 m / s or more. The present invention seeks to solve such a problem.

[0006]

The optical recording medium according to the present invention has a wavelength of 620 to 69 having an organic dye layer on a substrate.
An optical recording medium for recording / reproducing with a laser beam of 0 nm, wherein the organic dye layer contains a tricyanovinyl compound represented by the following general formula [I].

[0007]

Embedded image

(Where R¹And R^TwoAre independent
An optionally substituted alkyl group, alkenyl group,
Represents a cycloalkyl group or an aryl group;
¹And R ^TwoAre combined to form a heterocyclic ring or R¹When
R^ThreeAre combined to form a heterocyclic ring. R^ThreeIs R¹Combined with
Hydrogen atom, halogen
Or an optionally substituted alkyl group or
Shows an alkoxy group. )

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The optical recording medium according to the present invention basically has a configuration in which an organic dye layer is provided on a substrate. However, if desired, a metal reflective layer is formed on the organic dye layer or an ultraviolet curable resin film is laminated. May be. Alternatively, two media having an organic dye layer provided on a substrate may be attached to each other.

As the substrate, a known transparent substrate having a small birefringence, such as a polycarbonate substrate, an amorphous polyolefin substrate, or a glass substrate, is preferably used. The organic dye layer is usually formed by dissolving the organic dye in a solvent on a substrate and drying it, or by vacuum-depositing the organic dye on the substrate. As the solvent in the case of the coating method, for example,
In the case of a polycarbonate substrate, those which do not attack the polycarbonate substrate such as ethanol, 3-hydroxy-3-methyl-2-butanone, diacetone alcohol, and fluorinated alcohol are preferably used. In the case of a polyolefin substrate, chloroform, methyl ethyl ketone is used. And the like are preferably used.

The organic dye layer has a spectral absorption maximum of 510.
It is preferably in the range of nm to 730 nm. If the absorption maximum is outside this range, sufficient sensitivity may not be obtained, or a good reproduced signal may not be obtained. The thickness of the organic dye layer is preferably in the range of 20 to 100 nm. When the thickness of the organic dye layer is less than 20 nm, the coating film is formed only in the grooves, and it becomes difficult to perform the recording between the grooves. Conversely, 10
If it exceeds 0 nm, the rim becomes thicker or the asymmetry of the recording portion in the scanning direction of the laser beam is emphasized, so that the jitter in the bit length recording tends to deteriorate. In the present invention, a tricyanovinyl dye represented by the above general formula [I] is used in the organic dye layer.

In the above general formula (I), R ¹ and R ² are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec.
-Butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decyl group, n-dodecyl group, n-octadecyl group and other alkyl groups having 1 to 20 carbon atoms, preferably Is an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms; an aryl group having 6 to 12 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; a vinyl group and 1-propenyl Alkenyl group having 2 to 10 carbon atoms such as group, allyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group; arylalkyl group such as benzyl group and phenethyl group; cyclopropyl group And cycloalkyl groups having 3 to 10 carbon atoms, such as cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group.

The substituents bonded to these groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy,
C1-C10 alkoxy groups such as c-butoxy group, n-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n-decyloxy group; methoxymethoxy group, ethoxymethoxy A C2-12 alkoxyalkoxy group such as a group, a propoxymethoxy group, a methoxyethoxy group, an ethoxyethoxy group, a propoxyethoxy group, a methoxypropoxy group, an ethoxypropoxy group, a methoxybutoxy group, an ethoxybutoxy group; a methoxymethoxymethoxy group; C3-C15 alkoxyalkoxy such as methoxymethoxyethoxy, methoxyethoxymethoxy, methoxyethoxyethoxy, ethoxymethoxymethoxy, ethoxymethoxyethoxy, ethoxyethoxymethoxy, ethoxyethoxyethoxy, etc. Alkoxy group; allyloxy group;
An aryloxy group having 6 to 12 carbon atoms such as a phenoxy group, a tolyloxy group, a xylyloxy group, a naphthyloxy group; a cyano group; a nitro group; a hydroxy group; a tetrahydrofuryl group; a methylsulfonylamino group, an ethylsulfonylamino group, and n-propyl Sulfonylamino group, isopropylsulfonylamino group, n-butylsulfonylamino group, tert-butylsulfonylamino group, sec-
1 carbon atom such as butylsulfonylamino group, n-pentylsulfonylamino group, n-hexylsulfonylamino group, etc.
To 6 alkylsulfonylamino groups; halogen atoms such as fluorine, chlorine, and bromine; methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, tert-butoxycarbonyl Group, sec-butoxycarbonyl group, n-pentyloxycarbonyl group, n-hexyloxycarbonyl group, etc.
Alkoxycarbonyl group; methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, tert-butylcarbonyloxy group, sec-butylcarbonyloxy group, n- An alkylcarbonyloxy group having 2 to 7 carbon atoms such as a pentylcarbonyloxy group and an n-hexylcarbonyloxy group; a methoxycarbonyloxy group, an ethoxycarbonyloxy group, an n-propoxycarbonyloxy group, an isopropoxycarbonyloxy group, and an n-butoxy group Carbonyloxy group, tert-butoxycarbonyloxy group, s
Examples thereof include an alkoxycarbonyloxy group having 2 to 7 carbon atoms such as an ec-butoxycarbonyloxy group, an n-pentyloxycarbonyloxy group, and an n-hexyloxycarbonyloxy group.

Further, R¹Is R^TwoBinds to piperidine
Forming a heterocyclic ring such as a ring, a morpholine ring, or R^ThreeConclude with
They may combine to form a heterocyclic ring. R^ThreeIs R¹And join
Hydrogen atom when not forming a heterocyclic ring; methyl group;
1 carbon atom such as ethyl group, n-propyl group, n-butyl group, etc.
To 20 alkyl groups; methoxy group, ethoxy group, n-propyl
Alkoxy having 1 to 20 carbon atoms such as a loxy group and an n-butoxy group.
Coxy group; chlorine atom, bromine atom, iodine atom, fluorine atom
Represents a halogen atom or the like of a child or the like. R¹And R^TwoOr R ¹And R
^ThreeAnd a heterocyclic ring formed by bonding^ThreeDo not form a ring
The alkyl group and the alkoxy group in the above case include the aforementioned R¹,
R^TwoEven if the same substituent as described for is bonded
Good. Of the tricyanovinyl compound used in the present invention.
Some are illustrated in Table 1 below.

[0015]

Table 1 Table 1 Tricyanovinyl dye A-1 1- (P-diethylaminophenyl) -1,
2,2-tricyanoethylene A-21- (P-dimethylaminophenyl) -1,
2,2-Tricyanoethylene A-31- (P-di-n-propylaminophenyl)
-1,2,2-Tricyanoethylene A-41- (P-di-i-propylaminophenyl)
-1,2,2-tricyanoethylene A-5 1- (P-di-n-butylaminophenyl)-
1,2,2-tricyanoethylene A-6 1- (P-di-sec-butylaminophenyl) -1,2,2-tricyanoethylene A-7 1- (P-ethyl-n-butylaminophenyl) ) -1,2,2-Tricyanoethylene A-8 1- (P-ethyl- (2-ethyl-n-hexyl) aminophenyl) -1,2,2-tricyanoethylene A-9 1- (P- Di-n-pentylaminophenyl)
-1,2,2-Tricyanoethylene A-10 1- (P-bis (2-ethyl-n-hexyl)
Aminophenyl) -1,2,2-tricyanoethylene A-11 1- (P-ethyl-phenylaminophenyl)
-1,2,2-tricyanoethylene A-12 1- (P-ethyl- (p-methylphenyl) aminophenyl) -1,2,2-tricyanoethylene A-13 1- (P-ethyl- ( 3,5-dimethylphenyl) aminophenyl) -1,2,2-tricyanoethylene

[0016]

Table 1 (Continued) A-14 1- (P-ethyl-vinylaminophenyl)-
1,2,2-tricyanoethylene A-15 1- (P-ethyl- (2-methylvinyl) aminophenyl) -1,2,2-tricyanoethylene A-16 1- (P-ethyl-allylamino Phenyl)-
1,2,2-tricyanoethylene A-17 1- (P-ethyl- (3-methylallyl) aminophenyl) -1,2,2-tricyanoethylene A-18 1- (P-ethyl-benzylaminophenyl )
-1,2,2-Tricyanoethylene A-19 1- (P-ethyl-phenethylaminophenyl) -1,2,2-tricyanoethylene A-20 1- (P-ethyl-cyclopentylaminophenyl) -1 , 2,2-Tricyanoethylene A-21 1- (P-ethyl-cyclohexylaminophenyl) -1,2,2-tricyanoethylene A-22 1- (P-ethyl- (2-methoxyethyl) aminophenyl ) -1,2,2-Tricyanoethylene A-23 1- (P-ethyl- (2,3-dimethoxypropyl) aminophenyl) -1,2,2-tricyanoethylene A-24 1- (P- Ethyl- (2- (2-methoxyethoxy) ethyl) aminophenyl) -1,2,2-tricyanoethylene A-25 1- (P-ethyl- (2- (2- (2-methoxyethoxy) ethoxy) Ethyl) aminophenyl)-
1,2,2-tricyanoethylene A-26 1- (P-ethyl- (2-hydroxy-3-ethoxypropyl) aminophenyl) -1,2,2-tricyanoethylene

[0017]

Table 1 (continued) A-27 1- (P-bis (2-methoxyethyl) aminophenyl) -1,2,2-tricyanoethylene A-28 1- (P-bis (2- n-butoxyethyl) aminophenyl) -1,2,2-tricyanoethylene A-29 1- (P-ethyl- (p-methylphenoxy)
Methylaminophenyl) -1,2,2-tricyanoethylene A-30 1- (P-ethyl- (2-phenoxyethyl)
(Aminophenyl) -1,2,2-tricyanoethylene A-31 1- (P-ethyl- (2-cyclohexyloxyethyl) aminophenyl) -1,2,2-tricyanoethylene A-32 1- (P -Ethyl-tetrahydrofurfurylaminophenyl) -1,2,2-tricyanoethylene A-33 1- (P-ethyl- (2-hydroxyethyl)
Aminophenyl) -1,2,2-tricyanoethylene A-34 1- (P-ethyl- (2-cyanoethyl) aminophenyl) -1,2,2-tricyanoethylene A-35 1- (P-ethyl -(2-ethylsulfonylaminoethyl) aminophenyl) -1,2,2-tricyanoethylene A-36 1- (P-ethyl- (2-iodoethyl) aminophenyl) -1,2,2-tricyanoethylene A-37 1- (P-ethyl- (2-acetyloxyethyl) aminophenyl) -1,2,2-tricyanoethylene A-38 1- (P-ethyl- (2-ethoxycarbonylethyl) aminophenyl) -1,2,2-tricyanoethylene A-39 1- (P-ethyl- (2-ethoxycarbonyloxyethyl) aminophenyl) -1,2,2-tricyanoethylene

[0018]

Table 1 (Continued) A-40 1- (P-bis (2-acetyloxyethyl)
Aminophenyl) -1,2,2-tricyanoethylene A-41 1-P-piperidinophenyl-1,2,2-tricyanoethylene A-42 1-P-morpholinophenyl-1,2,2- Tricyanoethylene A-43 3- (3-methyl-4-diethylamino) phenyl-1,2,2-tricyanoethylene A-44 1- (3-chloro-4-diethylamino) phenyl-1,2,2- Tricyanoethylene A-45 1- (3-methoxy-4-diethylamino) phenyl-1,2,2-tricyanoethylene

[0019]

[Table 5]

[0020]

[Table 6]

[0021]

[Table 7]

These dyes may be used alone or
You may mix and use more than one kind. In order to further improve the weather resistance and the like, it may be used in combination with a quencher or a metal-containing azo dye. In order to perform recording and reproduction using the optical recording medium according to the present invention, wavelengths 620-690 n
m laser light is incident. The organic dye layer absorbs the incident laser light and generates heat. When the temperature reaches a temperature exceeding the main weight loss start temperature, the organic dye layer starts to be decomposed into fragments having a low molecular weight, thereby forming a concave portion. Since a slight amount or little of the dye remains in the concave portion, the reflectance decreases when the reproduction light is irradiated, and the concave portion is detected as a recording portion.

In general, in an optical recording medium having an organic dye layer, the shape of the recording portion greatly differs depending on the dye used, and the rim becomes thinner when the thickness of the organic dye layer is reduced.
The asymmetry of the recording section is not always improved. However, the optical recording medium having an organic dye layer containing a tricyanovinyl dye represented by the general formula [I] used in the present invention hardly forms a rim and has good jitter characteristics even at high linear velocity recording. Show.

[0024]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. Examples 1 to 6 As a transparent substrate, a recording groove having a diameter of 120 mm provided with a periodically meandering tracking groove for a recordable compact disc,
A polycarbonate substrate having a thickness of 1.2 mm was used. The organic dye solution shown in Table 2 was applied on this substrate by spin coating. Next, drying was performed in an oven at 100 ° C. for 30 minutes in order to completely evaporate the solvent in the dye layer.

Next, an average thickness of 100
The light reflecting layer was formed by depositing gold by a DC magnetron sputtering method so as to have a thickness of nm. Further, an ultraviolet curing agent SD-318 (Dainippon Ink Chemical Co., Ltd.) is provided on the light reflecting layer.
Was applied in a thickness of 4 μm by spin coating, and was cured by irradiating it with an ultraviolet ray using an ultraviolet ray irradiator to form a protective layer.

With respect to this optical recording medium, 635 nm
The recording of the EFM signal and the evaluation of the initial characteristics were performed using the semiconductor laser of No. 1, and the bit length jitter was good, and a recording portion having a good rim shape was obtained. Temperature 80 ° C, humidity 90
After a 500-hour high-temperature and high-humidity test under the conditions of%, the change in the block error rate was measured, and only a slight increase in error was found. The drive used in this evaluation is basically a drive in which only the optical head of the drive based on the current compact disc standard is changed to a 635 nm laser. The EFM signal modulation method and the like are the same as those of the current compact disc, and the block error rate was evaluated according to this modulation method.

[0027]

[Table 8] The indication of the dye is shown in Table 1.

Example 7 A groove having a depth of 150 nm and a width (half-width at half maximum) of 0.25 μm was formed at 0.1 mm.
A polycarbonate substrate having a thickness of 0.6 mm having a U-shaped guide groove formed at a pitch of 80 μm was used, and the dye of A-23 in Table 1 was added to octafluoropropanol at 2.5% by weight. A disk having a protective layer on the surface was manufactured in the same manner as in Example 1 except that the dissolved solution was used. The two disks were bonded with a hot melt adhesive to obtain an optical recording medium.

The recording medium was subjected to EF using a 640 nm semiconductor laser evaluator (numerical aperture NA = 0.6).
When the M signal was recorded and the initial characteristics were evaluated, the bit length jitter was good, and a recording portion having a good rim shape was obtained. After a high-temperature and high-humidity test for 500 hours at a temperature of 80 ° C. and a humidity of 90%, a change in the block error rate was measured. As a result, only a slight increase in the error was observed.

[0030]

As described above, the optical recording medium according to the present invention has a good minute recording portion having almost no rim, has a small bit length jitter, and can be suitably applied to short wavelength recording at a wavelength of 620 to 690 nm. So-called DVD-W / O, DVD-R
It is suitable for the standard called. Also, by increasing the clock frequency and the track pitch, good characteristics are exhibited even with a pitch of about half and a mark length of about half that of the current compact disc.

[Brief description of the drawings]

FIG. 1 shows spectral characteristics of a dye used in Example 1, and a broken line shows a spectrum of a chloroform solution (λmax = 524n).
m), the solid line is the spectrum (635) of the one applied to the substrate.
0.06).

FIG. 2 shows spectral characteristics of a dye used in Example 7, and a broken line shows a spectrum of a chloroform solution (λmax = 522n).
m), the solid line is the spectrum (635) of the one applied to the substrate.
0.06).

Claims (1)

[Claims] 1. Optical recording having an organic dye layer on a substrate
In the medium, the organic dye layer is represented by the following general formula [I].
Characterized by containing tricyanovinyl compounds
Recording / reproducing with laser light having a wavelength of 620 to 690 nm
Optical recording medium for short wavelength recording. Embedded image(Where R¹And R^TwoAre each independently substituted
Alkyl group, alkenyl group, cycloalkyl
Represents an aryl group or an aryl group;¹And R ^TwoTied
Together form a heterocycle or R¹And R^ThreeAre combined
To form a heterocycle. R^ThreeIs R¹To form a heterocyclic ring
If not, a hydrogen atom, a halogen atom, or
An alkyl group or an alkoxy group which may be substituted
Is shown. )