JPH08332772A - Optical recording medium - Google Patents

Abstract

PURPOSE: To eliminate the aging change by incorporating metal-containing azo compound containing specific azo compound and metallic salt in a light absorption layer and forming a light reflecting layer of a thin film of silver or silver alloy in an optical recording medium obtained by sequentially laminating the absorption layer, the reflecting layer and a protective layer on a transparent board. CONSTITUTION: The optical recording medium is obtained by sequentially laminating a light absorption layer, a light reflecting layer and a protective layer on a transparent board. In the medium, the absorption layer contains metal- containing azo compound containing azo compound represented by a formula and metallic salt. The reflecting layer is made of a thin film of silver or silver alloy. In the formula, R<1> and R<2> are independently hydrogen atom, alkyl group, aryl group, alkenyl group or cycloalkyl group which may be substituted, the R<1> and R<2> are cyclized to form a hydrocarbon ring or a heterocyclic ring, and the rings A and B may each has a substituent group. X is hydroxy group, carboxylic acid group, sulfonic group or their salts.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an optical recording medium. Specifically, it relates to an optical recording medium suitable for a write-once compact disc using an organic dye.

[0002]

2. Description of the Related Art An optical disc has a larger recording capacity than a conventional recording medium and can be randomly accessed.
It is widely used as a reproduction-only medium for audio software, computer software, game software, electronic publishing, and the like. On the other hand, write-once and rewritable recordable optical discs having an organic recording layer and an inorganic recording layer based on various recording principles have been developed and some of them have been put to practical use.

One of them is a recordable compact disc (CD-WO), which is capable of additional recording and has a reflectance equivalent to that of a read-only compact disc. It has the feature of being reproducible with. This recordable compact disc is usually produced by sequentially providing a light absorbing layer made of an organic dye such as a cyanine dye, a light reflecting layer made of a metal and a protective layer made of an ultraviolet curable resin on a transparent substrate having a guide groove, The record is 1
Deformation of the light absorption layer and its adjacent layer due to the heat mode using the laser beam narrowed down to about μm
It is performed due to alteration. In recent years, a high density compact disk standard has been proposed in which the track pitch is set to less than 1 μm and the laser light wavelength used is set to 600 to 680 nm, aiming at higher density. (Nikkei Electronics, February 27, 1995, p87-100) In such a high density standard, a recordable medium is also required.

[0004]

In the recordable compact disc which has been put to practical use and commercially available, the light reflection layer has a high reflectance of 65% or more and a high corrosion resistance with respect to the wavelength of the read laser beam (near 780 nm). In many cases, gold and alloys containing gold as a main component are used to obtain good properties, but this is a big problem in terms of cost because gold is expensive. Further, with gold, the reflectance tends to decrease with respect to laser light having a wavelength of 700 to 600 nm, which is considered to be the mainstream in the future.

It is conceivable to use a metal such as silver, copper, or aluminum having a high reflectance similar to that of gold at these wavelengths and an alloy containing them as a main component as the light reflecting layer, but in that case, The organic dye in the adjacent light-absorbing layer promotes corrosion of the light-reflecting layer, which tends to cause changes in disk characteristics over time, such as increased errors and reduced recording sensitivity. It was difficult to make a recordable compact disc.

The present invention solves the above-mentioned conventional problems, and uses a silver or silver alloy film which is a light reflection layer suitable for a high density compact disk utilizing a short wavelength of 700 to 600 nm, and an optical recording medium. It is an object of the present invention to provide a low-cost optical recording medium capable of high-density recording without impairing its life and reliability.

[0007]

As described above, when silver, copper, aluminum or an alloy containing them as a main component is used as the light reflecting layer instead of gold having high corrosion resistance, the light absorbing layer is There is a problem that the corrosion of the light reflecting layer is promoted from the interface between the light reflecting layer and the light reflecting layer, so that the characteristics of the disk tend to change with time such as an increase in errors and a decrease in recording sensitivity. Therefore, in order to overcome the above-mentioned problems, the present inventors have
As a result of earnestly examining the combination of the light reflection layer material and the organic dye effective in the wavelength range of 700 to 600 nm,
When the light reflecting layer is a thin film of silver or an alloy containing silver as a main component, it is easy to obtain a relatively high reflectance (at least 30%), and the organic dye forming the light absorbing layer further contains a metal. We have come to the knowledge that the addition of an azo dye can significantly suppress the change over time in the disk characteristics.

On the other hand, however, when the metal-containing azo compound is added to the organic dye forming the light absorbing layer, the recording and reproducing characteristics inherent to the organic dye forming the light absorbing layer may be impaired. As a result of a study on an effective metal-containing azo compound, when a metal-containing azo compound represented by the general formula [I] and a metal salt is used in the light absorbing layer, the recording / reproducing characteristics are hardly changed. It has been found that not only the corrosion of the light reflection layer made of a thin film of silver or a silver alloy is suppressed but also the crystallization and the light deterioration of the light absorption layer are suppressed and the high temperature and high humidity resistance is also improved. Completed

That is, the gist of the present invention is an optical recording medium in which a light absorbing layer, a light reflecting layer and a protective layer are sequentially laminated on a transparent substrate, wherein the light absorbing layer is represented by the general formula [I]. An optical recording medium is characterized by containing a metal-containing azo compound formed from a compound and a metal salt, and wherein the light-reflecting layer comprises a thin film of silver or a silver alloy.

[0010]

[Chemical 2](In the formula, R¹And R²Are independent hydrogen
Child, optionally substituted alkyl group, aryl group,
Represents an alkenyl group or a cycloalkyl group, R ¹When
R²Is cyclized to form a hydrocarbon or heterocycle
Good. Ring A and ring B may have a substituent.
X is a hydroxy group, a carboxylic acid group, a sulfonic acid group or
Represents these salts. ) These dyes are particularly good at 700 to 600 nm.
It has good absorption characteristics and refractive index.

The optical recording medium of the present invention will be described in detail below. Examples of the transparent substrate used in the present invention include plastics such as polycarbonate, polymethylmethacrylate, and amorphous polyolefin, or glass. These transparent substrates preferably have a thickness of 0.4 to 1.4 mm
A spiral guide groove is used.
The optical recording medium of the present invention is characterized in that the light absorption layer contains a metal-containing azo compound formed from the azo compound represented by the general formula [I] and a metal salt.

In the general formula [I], R ¹ and R
² each independently represents a hydrogen atom, an optionally substituted alkyl group, an aryl group, an alkenyl group or a cycloalkyl group, and more specifically, R ¹ and R
² are each independently a hydrogen atom; methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group,
tert-butyl group, sec-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decyl group, n-dodecyl group, n-octadecyl group, etc. An alkyl group having 20 carbon atoms, preferably 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; Vinyl group, 1
-C2-C10 alkenyl groups such as propenyl group, allyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group; or cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl Represents a cycloalkyl group having 3 to 10 carbon atoms such as a group, a cycloheptyl group and a cyclooctyl group. An alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 12 carbon atoms,
The alkenyl group having 2 to 10 carbon atoms and the cycloalkyl group having 3 to 10 carbon atoms are methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, te.
C1-C10 alkoxy groups such as rt-butoxy group, sec-butoxy group, n-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n-decyloxy group; methoxy Carbon number of 2 such as methoxy group, ethoxymethoxy group, propoxymethoxy group, methoxyethoxy group, ethoxyethoxy group, propoxyethoxy group, methoxypropoxy group, ethoxypropoxy group, methoxybutoxy group, ethoxybutoxy group
12 alkoxyalkoxy groups; 3 carbon atoms such as methoxymethoxymethoxy group, methoxymethoxyethoxy group, methoxyethoxymethoxy group, methoxyethoxyethoxy group, ethoxymethoxymethoxy group, ethoxymethoxyethoxy group, ethoxyethoxymethoxy group, ethoxyethoxyethoxy group, etc. To 15 alkoxyalkoxyalkoxy group; allyloxy group; aryl group having 6 to 12 carbon atoms such as phenyl group, tolyl group, xylyl group and naphthyl group; phenoxy group, tolyloxy group, xylyloxy group and naphthyloxy group having 6 carbon atoms 12 aryloxy groups;
Cyano group; nitro group, hydroxy group; tetrahydrofuryl group; methylsulfonylamino group, ethylsulfonylamino group, n-propylsulfonylamino group, isopropylsulfonylamino group, n-butylsulfonylamino group, tert-butylsulfonylamino group, sec -Butylsulfonylamino group, n-pentylsulfonylamino group, n-hexylsulfonylamino group and the like having 1 to 1 carbon atoms
6 alkylsulfonylamino group; halogen atom such as fluorine atom, chlorine atom, bromine atom; methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, tert-butoxycarbonyl group , Sec-butoxycarbonyl group, n-pentyloxycarbonyl group, n-hexyloxycarbonyl group and the like having 2 to 7 carbon atoms
Alkoxycarbonyl group: methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, tert-butylcarbonyloxy group, sec-butylcarbonyloxy group, n- C2-C7 alkylcarbonyloxy groups such as pentylcarbonyloxy group and n-hexylcarbonyloxy group; methoxycarbonyloxy, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, isopropoxycarbonyloxy group, n-butoxycarbonyl Oxy group, tert-butoxycarbonyloxy group, se
It may be substituted with an alkoxycarbonyloxy group having 2 to 7 carbon atoms such as a c-butoxycarbonyloxy group, an n-pentyloxycarbonyloxy group and an n-hexyloxycarbonyloxy group.

R ¹ and R ² may be cyclized to form a hydrocarbon ring or a heterocycle. Of these, an alkyl group having 1 to 5 carbon atoms is particularly preferable. In the general formula [I], the salt of the hydroxy group, the carboxylic acid group or the sulfonic acid group represented by X is Na ⁺ , Li ⁺ ,
Inorganic cations such as K ⁺ or P ⁺ (phenyl),
It represents a cation such as an organic cation such as N ⁺ (C ₂ H ₅ ), N ⁺ (C ₄ H ₉ (n)) ₄ , and (phenyl-N ⁺ ) (CH ₃ ) ₃ .

The metal of the metal salt is not particularly limited as long as it is a metal capable of forming a chelate compound with an azo compound which is a ligand, but nickel, cobalt, iron, ruthenium, rhodium, palladium, copper, osmium. , Transition elements such as iridium, platinum and zirconium are preferable,
Nickel, cobalt and palladium are particularly preferable. Ring A
May have a substituent, and as such a substituent,
Alkyl group, alkoxy group, thioalkoxy group, arylthio group, aryloxy group, aralkyl group, aryl group, halogen atom, cyano group, nitro group, ester group,
Examples thereof include a carbamoyl group, an acyl group, an acylamino group, a sulfamoyl group, a sulfinic acid group, an amino group, a hydroxyl group, a phenylazo group, a pyridinoazo group and a vinyl group, and these substituents may further have a substituent. . Preferred among these substituents are a hydroxyl group, a halogen atom, a cyano group, a nitro group and an optionally substituted alkyl group having 1 to 25 carbon atoms,
Alkoxy group having 1 to 25 carbon atoms, thioalkoxy group having 1 to 25 carbon atoms, arylthio group having 6 to 30 carbon atoms, alkylsulfamoyl group having 1 to 25 carbon atoms, and 6 to 3 carbon atoms
0 phenylsulfamoyl group, C1-25 alkylsulfinic acid group, C6-30 phenylsulfinic acid group, C6-30 pyridinoazo group, C2
~ 26 ester group, C2-C26 alkylcarbamoyl group, C6-C30 phenylcarbamoyl group,
Acyl group of 2 to 26 carbon atoms, acylamino group having 1 to 25 carbon atoms, -NR ³ R ⁴ (R ³ and R ⁴ are each independently a hydrogen atom, which may have a substituent, the carbon Representing an alkyl group or a phenyl group of the formulas 1 to 25, R ³ and R ⁴ may be bonded to each other to form a 5-membered ring or a 6-membered ring.), —CR ⁵ ═C (CN) R ⁶ ( R ⁵ is
Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ⁶
Represents a cyano group or an alkoxycarbonyl group having 2 to 7 carbon atoms. ) And the like, more preferably, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and 1 to 1 carbon atoms, which may have a substituent such as a halogen atom.
The thioalkoxy group of 10 and a halogen atom are mentioned.

Ring B may have a substituent other than the --NR ¹ R ² group and the --X group.
An alkyl group, preferably an alkyl group having 1 to 10 carbon atoms;
An alkoxy group, preferably an alkoxy group having 1 to 10 carbon atoms; a halogen atom and the like, and these alkyl groups,
The substituent such as an alkoxy group may further have a substituent such as a halogen atom. As one embodiment of the preferred compound in the present invention, the following general formula [II]

[0016]

Embedded image (Wherein Y represents a cation such as a hydrogen atom, an inorganic cation or an organic cation, and Z represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom) and a metal. Metal chelate compounds with salts are mentioned. Here, preferable specific examples of the monoazo compound of the general formula [I] are shown below.

[0017]

[Chemical 4]

[0018]

Embedded image

[0019]

[Chemical 6]

[0020]

[Chemical 7]

[0021]

Embedded image

[0022]

[Chemical 9]

[0023]

[Chemical 10]

[0024]

[Chemical 11]

[0025]

[Chemical 12]

[0026]

[Chemical 13]

[0027]

Embedded image

[0028]

[Chemical 15]

[0029]

Embedded image

[0030]

[Chemical 17]

Here, with respect to the metal-containing azo compound, particularly preferred R ¹ and R ² , a substituent of ring A, and a substituent of ring B (-
Table 1 shows combinations of metals other than NR ¹ R ² groups and —X groups), X and metal salts.

[0032]

[Table 1]

The metal-containing azo compound may be used alone or in combination of several kinds. Other organic dyes other than the metal-containing azo compound used in the light absorbing layer include cyanine dyes, squarylium dyes, croconium dyes, azulenium dyes, triarylamine dyes, anthraquinone dyes, and dithiol metal complex salt dyes. , Indoaniline metal complex dyes, phthalocyanine dyes, naphthalocyanine dyes, intermolecular CT dyes, etc. are used.
Cyanine dyes and phthalocyanine dyes, among them, cyanine dyes, particularly indolenine cyanine dyes are preferably used.

Other organic dyes other than the metal-containing azo compounds are
You may use each individually or in mixture of several types.
It is effective that the mixing ratio of the metal-containing azo compound in the light absorption layer is 5% by weight or more, more preferably 10 to 90% by weight. The metal-containing azo compound of the present invention is different from usual deterioration inhibitors, and since the metal-containing azo compound itself has good characteristics as an optical recording material, even if the compounding ratio of the metal-containing azo compound is increased. There is little change in the recording and reproducing characteristics, and it has the advantage that the characteristics peculiar to organic dyes are not impaired.

In the light absorption layer, in addition to the above-mentioned organic dye and metal-containing azo compound, a deterioration inhibitor for the organic dye,
A binder or the like may be added. As a method of forming the light absorbing layer, a method of dissolving an object to be coated in an organic solvent and spin coating the transparent substrate is preferably used. A thin film of silver or a silver alloy is used for the light reflection layer, and a method such as a sputtering method or a vacuum deposition method is used for forming the film. Particularly, the sputtering method is preferably used, and the light reflection layer has an incident angle with respect to the substrate surface. In the X-ray diffraction spectrum measured by the θ-2θ method with θ as θ, the X-ray diffraction intensity by the (111) plane is I ₁₁₁ and the X-ray diffraction intensity by the (200) plane is I.
_When it is set to ₂₀₀ , it is preferable to use a polycrystalline silver thin film such that I ₂₀₀ / I ₁₁₁ ≦ 0.2. The thickness of the light reflecting layer is preferably 50 to 200 nm. When a silver alloy thin film is used for the light reflection layer, its alloy composition is not particularly limited as long as it has a high reflectance for the reproduction laser light,
In order to improve corrosion resistance, additional elements such as rhodium, palladium, platinum, titanium, molybdenum, zirconium, tantalum, tungsten and vanadium may be contained in a range of 5 atomic% or less.

Further, in order to improve the corrosion resistance of the surface of the light reflection layer on the protective layer side, it is selected from triazinethiol compounds, triazineamine compounds, mercaptobenzimidazole compounds, thiodipropionate compounds and dithiocarbamate. Surface treatment with at least one compound may be applied. As the material of the protective layer formed on the light reflection layer, it is preferable to use an ultraviolet curable resin, particularly an acrylic ultraviolet curable resin, which is applied to a thickness of 2 to 20 μm by a spin coating method or a screen printing method, It is formed by being cured by ultraviolet irradiation. Further, the ultraviolet curable resin, as an anticorrosive agent for the surface of the protective layer side of the light reflection layer, from triazine thiol compounds, triazine amine compounds, mercaptobenzimidazole compounds, thiodipropionate compounds, dithiocarbamate salts You may use by making it contain at least 1 sort (s) of compound selected. A second protective layer or a printing layer such as a label may be provided on the protective layer, if necessary.

[0037]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Example 1 As a transparent substrate, a remarkably meandering tracking groove for a recordable compact disc was provided with a diameter of 120 mm,
A polycarbonate substrate having a thickness of 1.2 mm was used.

The light-absorbing layer was prepared by dissolving the metal-containing azo compound represented by the following structural formula (1) in tetrafluoropropanol at a concentration of 2.6% by weight, filtering the solution, and spin-coating it on the substrate. A film was formed. After applying the dye, drying was performed in an oven at 80 ° C. for 10 minutes in order to completely evaporate the solvent in the dye layer.

[0039]

Embedded image

Then, as a light reflecting layer on the light absorbing layer,
Silver having an average thickness of 100 nm was formed by the DC magnetron sputtering method. Further, an ultraviolet curing agent SD-318 (manufactured by Dainippon Ink and Chemicals, Inc.) was applied on the light reflecting layer by a spin coating method to a thickness of 3 μm, and was irradiated with ultraviolet rays by an ultraviolet irradiation device to be cured, A protective layer was formed.

Recording of the EFM signal and evaluation of the initial characteristics of the obtained recordable compact disc with a semiconductor laser of 635 nm were satisfactory. Temperature 8
When the change in block error rate was measured after a high temperature and high humidity test for 500 hours at 0 ° C. and 90% humidity,
Only a slight increase in error was seen. The results are shown in Table-2.

The drive used in this evaluation is basically the optical head of a drive that can be evaluated based on the current compact disk standard, but has 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 also evaluated based on this modulation method. Further, in the present compact disc, by increasing the clock frequency and the track pitch, good characteristics were obtained even with a half pitch (0.8 μm) and half mark length of the current compact disc. Example 2 The following structural formula (2)

[0043]

[Chemical 19]

A recordable compact disc was prepared in the same manner as in Example 1 except that the coating liquid was prepared by dissolving the metal-containing azo compound represented by the formula (3) in octafluoropentanol at a concentration of 1.3% by weight. did. The obtained disc was tested in the same manner as in Example 1 and found to be 650n.
m semiconductor laser, recording of EFM signal and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2. Example 3 The following structural formula (3)

[0045]

Embedded image

A recordable compact disc was prepared in the same manner as in Example 1 except that the coating solution was prepared by dissolving the metal-containing azo compound represented by the formula (3) in octafluoropentanol at a concentration of 1.3% by weight. did. The obtained disc was tested in the same manner as in Example 1 and found to be 650n.
m semiconductor laser, recording of EFM signal and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2. Example 4 The following structural formula (4)

[0047]

[Chemical 21]

A recordable compact disc was prepared in the same manner as in Example 1 except that the coating solution was prepared by dissolving the metal-containing azo compound represented by the formula (3) in tetrafluoropropanol at a concentration of 1.3% by weight. . The obtained disc was tested in the same manner as in Example 1 and found to be 635n.
m semiconductor laser, recording of EFM signal and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2. Example 5 The following structural formula (5)

[0049]

[Chemical formula 22]

A recordable compact disc was prepared in the same manner as in Example 1 except that the coating solution was prepared by dissolving the metal-containing azo compound represented by the formula (3) in tetrafluoropropanol at a concentration of 1.3% by weight. . The obtained disc was tested in the same manner as in Example 1 and found to be 650n.
m semiconductor laser, recording of EFM signal and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2. Example 6 The following structural formula (6)

[0051]

[Chemical formula 23]

A recordable compact disc was prepared in the same manner as in Example 1 except that the coating solution was prepared by dissolving the metal-containing azo compound represented by the formula (3) in octafluoropentanol at a concentration of 1.3% by weight. did. The obtained disc was tested in the same manner as in Example 1 and found to be 635n.
m semiconductor laser, recording of EFM signal and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2.

Example 7 A cyanine dye represented by the following structural formula (7) and a metal-containing azo compound represented by the above structural formula (1) were mixed in a weight ratio of 1: 1.
Then, a recordable compact disc was prepared in the same manner as in Example 1 except that the mixture was dissolved in tetrafluoropropanol at a concentration of 2.4% by weight to prepare a coating solution.

[0054]

[Chemical formula 24]

When the obtained disk was tested in the same manner as in Example 1, a 635 nm semiconductor laser was used.
Recording of EFM signals and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2.

Example 8 A cyanine dye represented by the following structural formula (8) and a metal-containing azo compound represented by the structural formula (4) were mixed in a weight ratio of 1: 1.
Then, a recordable compact disc was produced in the same manner as in Example 1 except that the mixture was dissolved in tetrafluoropropanol at a concentration of 1.3% by weight to prepare a coating solution.

[0057]

[Chemical 25]

When the obtained disk was tested in the same manner as in Example 1, a 635 nm semiconductor laser was used.
Recording of EFM signals and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2.

Example 9 A cyanine dye represented by the following structural formula (9) and a metal-containing azo compound represented by the above structural formula (5) were mixed in a weight ratio of 1: 1.
Then, a recordable compact disc was produced in the same manner as in Example 1 except that the mixture was dissolved in tetrafluoropropanol at a concentration of 1.3% by weight to prepare a coating solution.

[0060]

[Chemical formula 26]

When the obtained disk was tested in the same manner as in Example 1, a 650 nm semiconductor laser was used.
Recording of EFM signals and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2.

Example 10 A cyanine dye of the following structural formula (10), a dithiol nickel complex salt of the following structural formula (11) and a metal-containing azo compound of the above structural formula (1) were mixed in a weight ratio. After mixing 6: 1: 3, the mixture is added to 2.4 wt%
A recordable compact disc was produced in the same manner as in Example 1 except that the coating solution was prepared by dissolving the solution in tetrafluoropropanol at the concentration of.

[0063]

[Chemical 27]

When the obtained disk was tested in the same manner as in Example 1, a 635 nm semiconductor laser was used.
Recording of EFM signals and evaluation of initial characteristics were good. Further, when the test was conducted in the same manner as in Example 1, a slight increase in error was observed. The results are shown in Table-2.

Comparative Example 1 The procedure of Example 1 was repeated except that the cyanine dye represented by the structural formula (7) was dissolved in tetrafluoropropanol at a concentration of 2.4% by weight to prepare a coating solution. A recordable compact disc was prepared. When the obtained disc was tested in the same manner as in Example 1,
A large increase in errors was seen. The results are shown in Table-2.

Comparative Example 2 The cyanine dye shown by the structural formula (10) and the dithiol nickel complex salt dye shown by the structural formula (11) were mixed at a weight ratio of 6: 1, and then the mixture was mixed with 2.4. A recordable compact disc was prepared in the same manner as in Example 1 except that the coating solution was prepared by dissolving the solution in tetrafluoropropanol at a concentration of wt%. When the obtained disk was tested in the same manner as in Example 1, a large increase in errors was found. The results are shown in Table-2.

Comparative Example 3 The procedure of Example 1 was repeated except that the cyanine dye represented by the structural formula (8) was dissolved in tetrafluoropropanol at a concentration of 1.3% by weight to prepare a coating solution. A recordable compact disc was prepared. When the obtained disc was tested in the same manner as in Example 1,
A large increase in errors was seen. The results are shown in Table-2.

Reference Example In each of Examples 1 to 10 and Comparative Examples 1 to 3, recordable compact discs were manufactured in the same manner except that the light reflecting layer was made of gold. Each of the obtained disks was tested in the same manner as in Example 1. The results are shown in Table 2 in correspondence with each Example and Comparative Example.

[0069]

[Table 2]

The following is clear from Table-2. In Comparative Examples 1 to 3, after the high temperature and high humidity test, a great increase in block error due to corrosion of the light reflecting layer is observed. On the other hand, in Examples 1 to 10 to which the present invention was applied, the increase in block error was small even after the high temperature and high humidity test, and the disk reliability equivalent to that of the reference example using gold as the light reflecting layer was obtained. Has been obtained. The optical recording medium according to the present invention has a short wavelength (700 to 600 n) in addition to the EFM modulation method.
m) It is applicable to general mark length recording at high density using a laser.

[0071]

According to the present invention, a highly reliable optical recording medium having excellent durability can be manufactured at low cost and is industrially very useful.

Claims (2)

[Claims] 1. A light absorbing layer, a light reflecting layer, and a light absorbing layer on a transparent substrate.
In an optical recording medium in which protective layers are sequentially laminated, the optical absorption
An azo compound represented by the following general formula [I] and a metal salt
Containing a metal-containing azo compound formed from
Characterized in that the emissive layer is made of a thin film of silver or silver alloy
Optical recording medium. [Chemical 1](In the formula, R¹And R²Are independent hydrogen
Child, optionally substituted alkyl group, aryl group,
Represents an alkenyl group or a cycloalkyl group, R ¹When
R²Is cyclized to form a hydrocarbon or heterocycle
Good. Ring A and ring B may have a substituent.
X is a hydroxy group, a carboxylic acid group, a sulfonic acid group or
Represents these salts. ) 2. The optical recording medium according to claim 1, wherein the light absorbing layer contains a cyanine dye as an organic dye other than the metal-containing azo compound.