JPH0966671A - Optical record medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an optical record medium which is stable and can respond to the orange book standard and can record and regenerate even with a shortwave laser by sequentially layering, on a base material, a recording layer and a reflective layer which respectively have different two kinds of coloring matters having real parts and imaginary parts of specified complex indexes of refraction. SOLUTION: A recording layer and a reflective layer are sequentially layered on a base material. The recording layer contains a coloring matter A having a real part (n) of 1.8-2.8 and an imaginary part (k) of 0.15 or below of complex index of refraction at 780nm and a half value width of absorption spectrum of a thin film of 170nm or below, and a coloring matter B having a real part (n) of 1.8-2.8 and an imaginary part (k) of 0.2 or below of complex index of refraction at 630nm or 650nm. As a concrete example of the coloring matter A, a phthalocyanine coloring matter can be named and a trimethylene cyanine coloring matter can be named as a concrete example of the coloring matter B. By using these two kinds of coloring matters, excellent recording and regeneration can be done with a conventional wavelength of about 780nm and a wavelength (about 630-680nm) shorter than that.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium having a dye film as a recording layer, and particularly to a short wavelength (630 nm to 68 nm).
The present invention relates to a write-once type optical recording disk capable of recording and reproducing with two wavelengths of a wavelength of about 0 nm) and a conventional wavelength of about 780 nm.

[0002]

2. Description of the Related Art In recent years, various types of optical recording disks of the write-once type and the rewritable type have been receiving attention as large-capacity information carrying media. Some of such optical recording disks use a dye film containing a dye as a main component as a recording layer.
In terms of structure, a so-called air sandwich structure in which an air layer is provided on a recording layer made of a dye film that has been generally used conventionally, or a dye film that can be reproduced in compliance with the compact disc (CD) standard is used. There is proposed a structure in which a reflective layer is closely adhered to a recording layer made of (Nikkei Electronics, January 23, 1989, No. 4).
65, P107, Kinki Chemical Society Functional Dye Subcommittee, March 3, 1989, Osaka Science and Technology Center, PROC
EEDINGS SPIE-THE INTERNATIONAL SOCIETY FOR OPTICAL
ENGINEERING VOL.1078 PP80-87, "OPTICAL DATA STORAGE
TOPICAL MEETING "17-19, JANUARY 1989 LOS ANGELES
etc).

The above-mentioned recording layer is usually formed by coating a dye coating solution.

Recently, the demand for higher density recording has increased, and the wavelength of laser has been shortened. For example, JP-A-6-40161 and JP-A-6-40162 disclose optical recording media for short wavelength lasers using cyanine dyes.

Thus, recording with a short wavelength laser,
As the reproduction progresses, it is desired that the information recorded at the conventional laser wavelength of about 780 nm be read by the reproducing device using the short wavelength laser of about 630 nm to 680 nm, and vice versa. There is a demand for compatibility between recording / reproducing at a wavelength and recording / reproducing at a short wavelength.

However, although the proposals of Japanese Patent Laid-Open Nos. 6-40161 and 6-40162 can deal with the shortening of the wavelength, recording / reproducing at a wavelength of about 780 nm cannot be performed conventionally.

Further, Japanese Patent Application Laid-Open No. 7-52544 discloses that
An optical recording medium using a phthalocyanine dye having a specific structure is disclosed. By changing the structure of the medium, that is, by providing an air sandwich structure, recording and reproduction at a short wavelength are provided by closely attaching a reflective layer. It is said that such a structure enables recording and reproducing at a wavelength of about 780 nm.

However, in the proposal of Japanese Patent Application Laid-Open No. 7-52544, it is necessary to change the structure of the medium itself. Therefore, there is a demand for performing recording and reproducing on the same medium at different wavelengths of short wavelength and long wavelength. It does not meet.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical recording medium which is stable and capable of complying with the Orange Book standard and which can be recorded and reproduced by a short wavelength laser (wavelength of about 630 nm to 680 nm). Is to provide.

[0010]

This and other objects are achieved by the present invention which is defined below as (1) to (14). (1) In an optical recording medium having a recording layer and a reflective layer on a substrate, the recording layer has a real part n of complex refractive index at 780 nm of 1.8 to 2.8 and an imaginary part k of 0.15. And the real part n of the complex refractive index at 630 nm or 650 nm with the dye A whose half-value width of the absorption spectrum of the thin film is 170 nm or less.
Is 1.8 to 2.8 and the imaginary part k is 0.2 or less, and an optical recording medium containing the dye B. (2) The optical recording medium according to (1) above, wherein the dye A is a phthalocyanine dye represented by the following formula (I).

[0011]

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[In the formula (I), M represents a central atom. X ₁ , X ₂ , X ₃ and X ₄ each represent a halogen atom, which may be the same or different.
p1, p2, p3 and p4 are each 0 or an integer of 1 to 4, and p1 + p2 + p3 + p4 is 0 to 15.
Y ₁ , Y ₂ , Y ₃ and Y ₄ each represent an oxygen atom or a sulfur atom, which may be the same or different. Z ₁ , Z ₂ , Z ₃ and Z ₄ each represent an alkyl group having 4 or more carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group, which may be the same or different. Good. Each of q1, q2, q3 and q4 is 0 or an integer of 1 to 4, and these are not 0 at the same time, and q1 + q2 + q3 + q4 is 1 to 8. (3) The optical recording medium according to the above (2), wherein the bonding positions of the phthalocyanine ring of Y ₁ , Y ₂ , Y ₃ and Y ₄ are the 3-position and / or the 6-position. (4) The optical recording medium according to the above (2) or (3), wherein each of Z ₁ , Z ₂ , Z ₃ and Z ₄ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group. (5) The alicyclic hydrocarbon group or aromatic hydrocarbon group represented by Z ₁ , Z ₂ , Z ₃ and Z ₄ is Y ₁ , Y ₂ ,
The optical recording medium according to the above (4), which has a substituent at a position adjacent to each bonding position with Y ₃ and Y ₄ . (6) The optical recording medium according to any one of (1) to (5) above, wherein the dye B is a trimethine cyanine dye represented by the following formula (II).

[0013]

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[In the formula (II), Q ₁ and Q ₂ represent an atomic group necessary for completing a heterocycle with a carbon atom and a nitrogen atom, respectively, and a heterocyclic skeleton completed by Q ₁ or Q ₂ May be the same or different. R ₁ and R ₂ each represent an aliphatic hydrocarbon group, which may be the same or different. R ₃ represents a hydrogen atom or a monovalent substituent. X ⁻ represents a monovalent anion. (7) The optical recording medium according to (6) above, wherein the dye B is a trimethine indolenine cyanine dye represented by the following formula (III).

[0015]

[Chemical 6]

[In the formula (III), Q ₃ and Q ₄ each represent an atomic group necessary for completing an indolenine ring or a benzoindolenine ring together with a pyrrole ring, and a ring completed by Q ₃ or Q ₄ May be the same or different. R ₃ represents a hydrogen atom or a monovalent substituent. R
₄ and R ₅ each represent an alkyl group. X ⁻ represents a monovalent anion. (8) One of the rings completed with Q ₃ or Q ₄ together with the pyrrole ring is an indolenine ring,
The other is a benzoindolenine ring, and the position where the benzene ring of this benzoindolenine ring is condensed with the indolenine ring is the 4th and 5th positions of the indolenine ring. (9) The optical recording medium according to the above (8), which has a hydrogen atom, a halogen atom or an alkyl group at the 5-position of the indolenine ring. (10) Both the ring completed by Q ₃ or Q ₄ together with the pyrrole ring are benzoindolenine rings, and the position where the benzene ring of this benzoindolenine ring is condensed with the indolenine ring is the indolenine ring. The optical recording medium of (7) above, which is the fourth and fifth positions. (11) The optical recording medium according to any one of (7) to (10), wherein R ₄ and / or R ₅ is an alkoxyalkyl group. (12) The ratio of the dye A to the dye B in the recording layer, and the dye A / dye B in a weight ratio of 80/20 to 20/8
The optical recording medium according to any one of (1) to (11) above, which is 0. (13) The optical recording medium according to any one of the above (1) to (12), wherein the recording layer is formed by using a coating solution containing the dye A and the dye B, and the coating solvent is alkoxy alcohol. (14) The above (6) to (1) using a singlet oxygen quencher as a stabilizer together with the trimethine cyanine dye.
3) Any of the optical recording media.

[0017]

The optical recording medium of the present invention has a recording layer containing a dye on the substrate. 780nm as dye in the recording layer
The real part n of the complex index of refraction at the wavelength is 1.8 to 2.8,
The imaginary part k is 0.15 or less, the half-value width of the absorption spectrum of the dye thin film is 170 nm or less, and the real part n of the complex refractive index at 630 nm or 650 nm is 1.8 to
2.8, a dye B having an imaginary part k of 0.2 or less is used.
By using two kinds of dyes having such optical characteristics in combination, excellent recording and reproduction can be performed in the conventional wavelength of about 780 nm and a shorter wavelength region (wavelength of about 630 to 680 nm). That is, since the dye A has n and k as described above, 780 nm
Sufficient reflectivity and signal modulation at conventional wavelengths of the order of magnitude are obtained. Further, since the dye A has a full width at half maximum of 170 nm or less in the absorption spectrum of the dye thin film, it does not have large absorption in the short wavelength region, and the real part n of the complex refractive index in the short wavelength region becomes small. Therefore, with the dye A, the degree of modulation of a signal at a short wavelength becomes extremely small, making it impossible to read or degrading the error rate. However, the dye B has n and k as described above, and the dye A does not have the absorption edge of the absorption spectrum of the dye thin film in the wavelength region of the short wavelength laser. Can be utilized as it is, and the reflectance in the short wavelength range is not lowered. Therefore, the reflectance and the degree of modulation at a short wavelength are sufficiently large.

As described above, the dye in the present invention is a CD
It can be used for the recording layer of an optical recording medium conforming to the standard, and recording and reproducing can be performed even with a short wavelength laser.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

The optical recording medium of the present invention has a recording layer on the substrate and a reflective layer on the recording layer.

The recording layer is a dye film containing a dye, and dyes A and B are used as the dye.

The dye A has a real part n of the complex refractive index at 780 nm of 1.8 to 2.8 and an imaginary part (extinction coefficient) k of 0.15.
Below, it is preferably 0.02 to 0.13. By using such n and k, sufficient reflectivity and signal modulation degree can be obtained. On the other hand, when n is less than 1.8, the modulation degree of the signal becomes small, and when k exceeds 0.15, sufficient reflectance cannot be obtained. And n
It is practically impossible to synthesize a dye having a value of more than 2.8.

As for the dyes n and k, a dye film is formed on a predetermined transparent substrate under the same condition as that of the recording layer of the optical recording medium to a thickness of the recording layer, for example, 40 to 100 nm. To prepare a measurement sample, and then measure the reflectance and transmittance at 780 nm of this measurement sample,
From these measured values, for example, it is calculated in accordance with Kyoritsu Zensho "Optical" Kozo Ishiguro P168-178. The reflectance is the reflectance of the measurement sample through the substrate or the reflectance from the dye film side, and is measured by specular reflection (about 5 °).

Dye A has an absorption maximum (λmax) of 680 to 75 when the absorption spectrum of the dye thin film is measured.
Although it is about 0 nm, the full width at half maximum of the absorption spectrum, that is, the full width at half maximum of the spectral line near λmax is 170 nm or less, preferably 150 nm or less. The lower limit of the full width at half maximum is not particularly limited, but is usually 50 nm. By using such a half width, the absorption characteristics of the dye B are not affected and the reflectance and the degree of modulation in the short wavelength region are sufficient. On the other hand, if the full width at half maximum exceeds 170 nm, the absorption edge is in the wavelength range of the short-wavelength laser, and the reflectance is reduced in the short-wavelength range. The half value width was determined by preparing a sample in which a dye film was formed on a transparent substrate so that the transmittance T at the absorption maximum λmax was 25% or less, and measuring the absorption spectrum of this sample. For example, to explain according to the absorption spectrum of FIG. 1, the transmittance T _{1 at} λmax and the transmittance T ₂ which becomes substantially constant without depending on the shift of the wavelength when the wavelength is shifted to the longer wavelength side are obtained. T ₂ and the bottom of the depth of half the width △ lambda half width of up to T ₁ as baseline (base). The thickness of the dye film of the sample is usually about 50 to 150 nm.

On the other hand, the dye B used in combination with the dye A is 630
nm or 650 nm, the real part n of the complex refractive index is 1.8
~ 2.8, imaginary part k is 0.2 or less, preferably 0 to 0.1
Five. By using such n and k, sufficient reflectivity and signal modulation degree can be obtained.
On the other hand, when n is less than 1.8, the modulation degree of the signal becomes small, and when k exceeds 0.2, a sufficient reflectance cannot be obtained. Moreover, it is virtually impossible to synthesize a dye having n of 2.8 or more. In this case, n and k are obtained in the same manner as the dye A except that the measurement wavelength is 630 nm or 650 nm.

The ratio of the dye A to the dye B in the recording layer is such that the weight ratio of dye A / dye B is 80/20 to 20/80.
It is preferred that With such a ratio,
Recording and reproduction can be performed with two wavelengths, a short wavelength and a conventional wavelength, and recording and reproduction can be performed separately for these two wavelengths. On the other hand, if one of the dyes A or B is too much or too little, recording and reproducing at any wavelength becomes difficult. In addition, dye A
Each of B and B may be used alone, or two or more may be used in combination, and when two or more are used in combination, the total amount may be the above weight ratio.

The n and k of such a recording layer are 630
nm or 650 nm, n = 1.8 to 2.3, k =
0.03 to 0.20, n = 1.8 at 780 nm
2.5, k = 0.03 to 0.15, and 630 to 68
It is shown that recording / reproducing can be favorably performed at a wavelength of about 0 nm and a wavelength of about 780 nm. In this case, n and k are obtained in the same manner as the dye film.

As the dye A, it is preferable to use a dye that has a large steric hindrance and is unlikely to cause molecular association when formed into a thin film. This is because the absorption spectrum of a dye thin film in which molecular association does not easily occur tends to have a narrow half width. Further, the solubility when preparing the dye-containing coating liquid is improved.

As the dye A, specifically, a phthalocyanine dye, a naphthalocyanine dye, and the like are preferable, and a phthalocyanine dye is more preferable. In particular, the phthalocyanine dye represented by the formula (I) [listed in Chemical Formula 4 above] is preferable.

Regarding formula (I), M represents a central atom in formula (I). The central atom represented by M includes a hydrogen atom (2H) or a metal atom. As the metal atom at this time, the periodic table groups 1 to 14 (1A to
It may be a metal atom belonging to 7A group, 8 group, 1B-4B group), and specifically, Li, Na, K, Mg, Ca, B.
a, Ti, Zr, V, Nb, Ta, Cr, Mo, W, M
n, Tc, Fe, Co, Ni, Ru, Rh, Pd, O
s, Ir, Pt, Cu, Ag, Au, Zn, Cd, H
g, Al, In, Tl, Si, Ge, Sn, Pb, etc., especially Li, Na, K, Mg, Ca, Ba, Ti, Zr,
V, Nb, Ta, Cr, Mo, W, Mn, Tc, Fe,
Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, C
u, Ag, Au, Cd, Hg, Al, In, Tl, S
Examples thereof include i, Ge, Sn, and Pb. Among these, A
l, Si, Ge, Zn, Cu, Pd, Ni, Fe, Co
Etc. are preferable, and particularly Cu, Pd, Ni, Fe, Co, V
O and the like are preferable in terms of stability over time.

Incidentally, these metal atoms may be in the form of VO, such as V, and further Si, Al,
It may be in a form in which a ligand such as an ether group, an ester group, pyridine and a derivative thereof is further coordinated to the upper and lower sides or one side of a metal atom such as Ge, Co and Fe.

X _{1 to} X ₄ each represent a halogen atom,
The halogen atom includes F, Cl, Br, I and the like. Particularly, Br and F are preferable.

P1, p2, p3 and p4 are each 0 or an integer of 1 to 4, and p1 + p2 + p3 + p4 is 0 to
15 and preferably 0 to 10.

X _{1 to} X ₄ may be the same or different, and when p1, p2, p3 and p4 are each an integer of 2 or more, X _1's , X _2's , X _3's , X ₄
They may be the same or different.

Y _{1 to} Y ₄ each represent an oxygen atom or a sulfur atom, and particularly preferably an oxygen atom. Y _{1 to} Y
₄ are usually the same, but may be different. Z
_{1 to} Z ₄ each represent an alkyl group having 4 or more carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group,
These may be the same or different.

Q1, q2, q3 and q4 are each 0 or an integer of 1 to 4, and they are not 0 at the same time, and q1 + q2 + q3 + q4 is 1 to 8, preferably 2 to 6.

The bonding position of Y _{1 to} Y ₄ with respect to the phthalocyanine ring is preferably the 3-position and / or the 6-position (see the following structural formula) of the phthalocyanine ring, and at least one such bond is contained. preferable.

[0038]

[Chemical 7]

The alkyl group represented by X _{1 to} X ₄ is preferably one having 4 to 16 carbon atoms, which may be linear or branched, but one having branched is preferred. preferable. It may have a substituent, and examples of the substituent include a halogen atom (F, Cl, Br, I, etc., particularly preferably F, Br, etc.) and the like. Specific examples of such alkyl _{groups, n-C 4 H 9,} i-C 4 H
_{9 -, s-C 4 H} 9 -, t-C 4 H 9 -, n-C 5 H 11
_{-, (CH 3) 2 CHCH} 2 CH 2 -, (CH 3) 3 C
_{CH 2 -, (C 2 H} 5) 2 CH-, C 2 H 5 C (CH
_{3) 2 -, n-C} 3 H 7 CH (CH 3) -, n-C 6 H
_{13 -, (CH 3) 2} CHCH 2 CH 2 CH 2 -, (CH
_{3) 3 C-CH 2 -CH} 2 -, n-C 3 H 7 CH (CH
_{3) CH 2 -, n-} C 4 H 9 CH (CH 3) -, n-C 7
_{H 15 -, [(CH 3} ) 2 CH] 2 -CH-, n-C 4 H
_{9 CH (CH 3) CH 2} -, (CH 3) 2 CHCH 2 C
_{H (CH 3) CH 2 -} , n-C 8 H 17 -, (CH 3) 3
_{CCH 2 CH (CH 3) CH} 2 -, (CH 3) 2 CHC
_{H (i-C 4 H 9} ) -, n-C 4 H 9 CH (C 2 H 5)
_{CH 2 -, n-C 9} H 19 -, CH 3 CH 2 CH (CH
_{3) CH 2 CH (CH 3} ) CH 2 CH 2 -, (CH 3)
_{2 CHCH 2 CH 2 CH 2 CH} (CH 3) CH 2 -, n
_{-C 3 H 7 CH (CH 3} ) CH 2 CH (CH 3) CH 2
_{-, n-C 10 H 21} -, (CH 3) 3 CCH 2 CH 2 C
_{(CH 3) 2 CH 2 -} , n-C 11 H 23 -, n-C 12 H 25
_{-, n-C 13 H 27} -, n-C 14 H 29 -, n-C 15 H
_{31 -, n-C 16 H} 33 -, n-C 4 F 9 -, i-C 4 F 9
_{-, s-C 4 F 9} -, t-C 4 F 9 - , and the like.

Examples of the alicyclic hydrocarbon group represented by Z _{1 to} Z ₄ include a cyclohexyl group and a cyclopentyl group, with a cyclohexyl group being preferred. These may further have a substituent, and examples of such a substituent include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an aralkyl group, a halogen atom, a nitro group, a carboxyl group, an ester group, and an acyl group. Group, amino group, amido group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfo group, sulfino group, arylazo group, alkylthio group, arylthio group, and the like, and among them, an alkyl group having 1 to 5 carbon atoms (for example, methyl group). Group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-
Butyl group, n-pentyl group, iso-pentyl group, ne
o-pentyl group, tert-pentyl group, 1-methylbutyl group), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group), Aryl group (eg phenyl group, tolyl group, biphenyl group, naphthyl group), halogen atom (eg F,
Cl, Br, I, preferably F, Br) and the like are preferable.
The substitution position of these substituents is preferably one or both of the adjacent positions of the bonding positions of Y _{1 to} Y ₄ , and preferably at least one such substitution is included.

The aromatic hydrocarbon group represented by Z _{1 to} Z ₄ may be a monocyclic ring or a condensed ring, and may further have a substituent. The total number of carbon atoms is preferably 6-20. Specific examples thereof include a phenyl group and a naphthyl group, and a phenyl group is preferable. These may further have a substituent, and examples of such a substituent include those similar to those exemplified in the alicyclic hydrocarbon group, and the preferable ones are also the same. The preferred substitution position is also the same, and it is preferably the ortho position of the bonding position of Y _{1 to} Y ₄ , and preferably at least one ortho substitution is included.

The heterocyclic group represented by Z _{1 to} Z ₄ is
It may be a monocyclic ring or a condensed ring, and the hetero atom is preferably oxygen, nitrogen, sulfur or the like, particularly oxygen, nitrogen or the like. Specific examples thereof include a pyridyl group, a furanone-yl group, a pyrazyl group, a pyrazolidyl group, a piperidinone-yl group, a quinoxalyl group, a pyranone-yl group, and a thiophentrione-yl group, and a pyridyl group, 2-
A furanone-yl group is preferred. These heterocyclic groups are
Further, it may have a substituent, and examples of the substituent include those exemplified for the alicyclic hydrocarbon group and aromatic hydrocarbon group, and the preferable ones are also the same. In particular, when a carbon atom is present at a position adjacent to the bonding position of Y _{1 to} Y ₄ , it is preferable to have a substituent at such a position.

As Z _{1 to} Z ₄ , an alicyclic hydrocarbon group and an aromatic hydrocarbon group are particularly preferable, a cyclohexyl group and a phenyl group are more preferable, and at least one of the bonding positions of Y ₁ to Y ₄ is particularly preferable. Those having a substituent (particularly the above-mentioned preferred substituent) at the position adjacent to are preferable.

Specific examples of such phthalocyanine dyes are shown below, but the present invention is not limited thereto. Specific examples include X _{11 to} X ₁₄ in the following formula (Ia) [Chemical formula 8],
_{X 15 ~X 18, X 19 ~X} 22, shows with X ₂₃ to X ₂₆ and M, X ₁₁ when all the to X _14, etc. is H by H, also itself when a substituent Shows only H
Is not shown.

[0045]

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[0046]

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[0047]

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[0048]

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[0049]

[Chemical 12]

[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

[Chemical 21]

[0059]

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These phthalocyanine dyes can be synthesized by referring to the methods described in JP-A-63-313760 and JP-A-63-301261.

A synthesis example is shown below.

Synthesis Example 1 Synthesis of Dye No. A-1 1.73 g of 1,2-dicyano-3-nitrobenzene and 4.12 g of 2,4-di-tert-butyl-hydroxybenzene were mixed with dimethylformamide (DMF). 5 ml
Then, 5.0 g of K ₂ CO ₃ was added and the reaction was carried out at 80 ° C. for 2 hours. After the reaction, water / ethyl acetate (1/1 by volume)
Extract with a mixed solvent twice, and extract the ethyl acetate layer with MgSO _4.
After drying overnight using ethyl acetate, the ethyl acetate was distilled off, and the residue was purified by silica gel column chromatography using chloroform, and 1,2-dicyano-3- (2,4-
2.65 g of tert-butylphenyloxy) benzene
Was obtained (80% yield).

Next, 1.66 g of this compound and CuCl
0.20 g of 1,8-diazabicyclo [5.4.0] -7-undecene (DB) in 10 ml of amyl alcohol
U) In the presence of 1.52 g, the mixture was heated to reflux at 200 ° C. for 5 hours for reaction, and the reaction product thus obtained was separated by silica gel column chromatography using chloroform to obtain 1.22 g of the desired product. (Yield 70
%, Mp 285-290 ° C).

Synthesis Example 2 Synthesis of Dye No. A-3 Synthesis was carried out in the same manner as in Synthesis Example 1 as follows.

1.73 g of 1,2-dicyano-3-nitrobenzene and 4.68 g of 2-tert-butylcyclohexanol were added to 5 ml of dimethylformamide (DMF).
Then, 5.0 g of K ₂ CO ₃ was added and the reaction was carried out at 80 ° C. for 2 hours. After the reaction, water / ethyl acetate (1/1 by volume)
Extract with a mixed solvent twice, and extract the ethyl acetate layer with MgSO _4.
After drying overnight using ethyl acetate, the ethyl acetate was distilled off, and the residue was purified by silica gel column chromatography using chloroform, and 1,2-dicyano-2-tert-
1.41 g of butylcyclohexyloxy) benzene was obtained (yield 50%).

Next, 1.41 g of this compound and CuCl
0.14 g of 1,8-diazabicyclo [5.4.0] -7-undecene (DB) in 10 ml of amyl alcohol
U) In the presence of 0.76 g, the mixture was reacted by heating under reflux at 200 ° C. for 5 hours, and the reaction product thus obtained was separated by silica gel column chromatography using chloroform to obtain 0.97 g of the desired product. (Yield 65
%, Mp 220-222 ° C).

Other dyes exemplified as above or according to the above were synthesized (yield about 45 to 80%).

These dyes can be identified by elemental analysis, visible absorption spectrum, infrared absorption spectrum, mass spectrum, nuclear magnetic resonance absorption spectrum and the like.

The melting point (mp) of these dyes is 60 to 40.
0 ° C.

780 nm of these phthalocyanine dyes
Are shown in Tables 1 and 2. These n and k are obtained by setting the thickness of the dye film to 80 nm. Further, the half width of the absorption spectrum of the dye thin film was determined as described above, and these results and λmax (thin film) are also shown.

[0071]

[Table 1]

[0072]

[Table 2]

As described above, the dye A may be used alone or in combination of two or more. When two or more kinds are used in combination, they may be selected and used so that the half widths of n, k and the absorption spectrum of the thin film fall within the above-mentioned ranges.

On the other hand, as the dye B, n and k described above are used.
There is no particular limitation as long as the above conditions are satisfied, and examples thereof include a trimethine cyanine dye, a metal complex dye, a styryl dye, a porphyrin dye, an azo dye, an azo metal complex dye, and a formazan metal complex. Although these dyes are described above, only one kind may be used or two or more kinds may be used in combination. When two or more kinds are used in combination, they may be selected and used so that the above n and k fall within the above ranges.

Among these dyes, the trimethine cyanine dye and the like are used because of their easy availability. Examples of the trimethine cyanine dye include those represented by the formula (II) [listed in the above chemical formula 5].

The formula (II) will be described below.
Wherein Q ₁ and Q ₂ represent an atomic group necessary for completing a heterocycle with a carbon atom and a nitrogen atom, respectively, and the heterocyclic skeleton completed by Q ₁ or Q ₂ may be the same or different. Although good, it is preferable that they have the same skeleton in terms of synthesis. Such a heterocyclic skeleton is preferably a benzothiazole skeleton, a thiazole skeleton, an oxazole skeleton,
Examples thereof include a benzoxazole skeleton, a pyridine skeleton, a quinoline skeleton, an imidazole skeleton, an indolenine skeleton, a benzoindolenine skeleton, and a dibenzoindolenin skeleton.

The heterocyclic ring completed by Q ₁ or Q ₂ may have a substituent, and such a substituent includes a halogen atom, an alkyl group, an aryl group, an acyl group, an amino group and the like. .

R ₁ and R ₂ each represent an aliphatic hydrocarbon group, which may be the same or different. Examples of the aliphatic hydrocarbon group include an alkyl group and a cycloalkyl group. The alkyl group has 1 to 4 carbon atoms.
Are preferred, methyl group, ethyl group, propyl group,
Butyl group etc. Moreover, a cyclohexyl group etc. are mentioned as a cycloalkyl group. This compound may have a substituent, and examples of the substituent include a halogen atom, an ether group such as an alkyl group, an aryl group, an alkoxy group, an ester group, and a heterocyclic group. Of these, an unsubstituted alkyl group is preferable, and particularly a methyl group,
Ethyl group, butyl group and the like are preferable. From the viewpoint of solubility in the coating solvent, an alkoxyalkyl group having an ether bond, etc., preferably an alkoxyalkyl group having a total carbon number of 3 to 6 is preferable.

R ₃ represents a hydrogen atom or a monovalent substituent. As the monovalent substituent, an alkyl group, an aryl group,
Examples thereof include an azo group, an ester group, an acyl group, a halogen atom and a heterocyclic group, and among these monovalent groups, an alkyl group, an aryl group, an azo group, an ester group, an acyl group and a heterocyclic group may have a substituent. You may have. When it has a substituent, examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an amino group, a heterocyclic group and a nitro group.

X ⁻ represents a monovalent anion, ClO ₄ ⁻ ,
Examples thereof include I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , and paratoluenesulfonate ion.

Among the trimethine cyanine dyes represented by the formula (II), the trimethine indolenine cyanine dye represented by the formula (III) [shown in the above chemical formula 6] is preferable.

Describing formula (III), in formula (III), Q ₃ and Q ₄ each represent a group of atoms necessary to complete an indolenine ring or a benzoindolenine ring together with a pyrrole ring, and Q ₃ or The rings completed in Q ₄ may be the same or different. Moreover, such an indolenine ring or a benzoindolenine ring may have a substituent, and such a substituent includes a halogen atom, an alkyl group, an aryl group, an acyl group, an amino group, and the like.

When the ring completed by Q ₃ or Q ₄ is a benzoindolenine ring, there is no particular limitation on the position of condensation of the benzene ring with respect to the indolenine ring. It is preferable that the rings are condensed (see the following formula (IIIa): Chemical formula 23).

Especially in the case of 630 to 640 nm, Q
_{A combination in which one of 3} , Q ₄ is an indolenine ring and the other is a benzoindolenine ring is preferable, and a combination of more than 640 to 680
In the case of nm correspondence, a combination in which both Q ₃ and Q ₄ are benzoindolenin rings is preferable.

R ₃ represents a hydrogen atom or a monovalent substituent and has the same meaning as R _{3 in} formula (II). R ₃ is preferably a hydrogen atom.

R ₄ and R ₅ each represent an alkyl group.
The alkyl group may have a substituent and preferably has 1 to 4 carbon atoms. Examples of the substituent include the same substituents as R ₁ and R _2. Especially, alkoxy and the like are preferable. The alkyl group represented by R ₄ and R ₅ is a methyl group, an ethyl group, or (n
Examples include-, i-) propyl group, (n-, i-, s-, t-) butyl group, methoxymethyl group, methoxyethyl group and ethoxyethyl group.

R ₄ and R ₅ are unsubstituted alkyl groups,
An alkoxyalkyl group or the like is preferable, and in the sense of improving solubility in a coating solvent, at least one of R ₄ and R ₅ is an alkoxyalkyl group, preferably an alkoxyalkyl group having 3 to 6 carbon atoms in total. Is preferred.

[0088] X ^- represents an anion, X of formula (II) ^- is of the same meaning.

Among the trimethine indolenine cyanine dyes represented by the formula (III), those represented by the following formulas (IIIa) and (IIIb) are preferable.

Those represented by the formula (IIIa) are 630 to 640.
is 640 nm and is represented by formula (IIIb).
It is compatible with ultra-680 nm.

[0091]

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[0092]

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In the formulas (IIIa) and (IIIb), R ₁₁ and R ₁₂ have the same meanings as R ₄ and R _{5 in} the formula (III), respectively.
₃ is of the same meaning as R ₃ of In the formula (III), the is preferably a hydrogen atom, X ^- is X in formula (III) ^- is of the same meaning. In formula (IIIa), R ₁₃ represents a hydrogen atom, a halogen atom or an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms.

[0094] Incidentally, formula (IIIa), an indolenine ring in (IIIb), a benzindolenine ring, in addition to the above R _13,
Further, it may have a substituent such as a halogen atom, an alkyl group, an aryl group, an acyl group and an amino group.

Further, R ₁₁ and R ₁₂ in the formulas (IIIa) and (IIIb) are preferably an unsubstituted alkyl group, an alkoxyalkyl group or the like, which improves the solubility in a coating solvent and obtains a coating film having good properties. From the viewpoint, it is preferable that either one or both of them is an alkoxyalkyl group, and specific examples thereof include a methoxymethyl group, a methoxyethyl group, an ethoxyethyl group, etc. Can be mentioned. The alkoxyalkyl group preferably has 3 to 6 carbon atoms in total.

Specific examples of the trimethine cyanine dye used in the present invention are shown below, but the present invention is not limited thereto.

[0097]

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[0098]

[Chemical formula 26]

[0099]

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[0100]

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[0101]

[Chemical 29]

These trimethine cyanine dyes may be used alone or in combination of two or more. Λ max of trimethine cyanine dye (measured with dye thin film of 80 nm thickness) is 5
60 to 620 nm and its melting point (mp) is 100 to 3
It is 00 ° C.

Table 3 shows λ max of these trimethine cyanine dyes and n and k at 630 nm or 650 nm obtained by setting the thickness of the dye film to 80 nm.

[0104]

[Table 3]

In the present invention, in order to improve the light resistance of the trimethine cyanine dye, it is preferable to use a metal complex quencher which is a singlet oxygen quencher as a stabilizer together with the trimethine cyanine dye. Examples of such a metal complex quencher include JP-A-59-59795,
The compounds described in No. 60-118748, No. 60-18749 and the like can be used.

Examples of such metal complex quenchers include acetylacetonates, bisdithiols such as bisdithio-α-diketones and bisphenyldithiols, thiocatechols, salicylaldehyde oximes and thiobisphenolates. The metal complex quencher of is mentioned. Among them, a bisphenyldithiol-based metal complex quencher is preferable, and N is used as the central metal.
i, Cu, Co, Pd, Pt and the like, Ni, Cu
Etc., and Cu is particularly preferable.

The amount of these metal complex quenchers used may be appropriately determined depending on the dye used.

The metal complex quencher may be used in the form of a conjugate in which the counter anion of the trimethine cyanine dye cation, that is, X ⁻ of formula (II) is the metal complex quencher anion. Preferred in this case are the anions of the same metal complex quenchers as described above, and above all,
Bisphenyldiol-based metal complex quencher anions are preferable, and preferable center metals are also the same as above. The conjugate can be obtained by salt exchange.

The recording layer using the dyes A and B is particularly preferably used for a write-once type optical recording disk (CD-R). Such a recording layer is preferably formed using a dye-containing coating solution. Particularly, it is preferable to use the spin coating method in which the coating liquid is spread and coated on the rotating substrate.

As the coating solvent at this time, specifically,
Alcohol type (including keto alcohol type, alkoxy alcohol type such as ethylene glycol monoalkyl ether type), aliphatic hydrocarbon type, ketone type, ester type,
It may be appropriately selected from ether type, aromatic type, alkyl halide type and the like.

Of these, alcohol type and aliphatic hydrocarbon type are preferable. Among alcohols, alkoxy alcohols and keto alcohols are preferred.
In the alkoxy alcohol system, the alkoxy moiety preferably has 1 to 4 carbon atoms, and the alcohol moiety has 1 to 5 carbon atoms, more preferably 2 to 5 carbon atoms, and the total carbon atom is 3 To 7 is preferable.
Specifically, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (also referred to as ethyl cellosolve, ethoxyethanol), butyl cellosolve, 2-isopropoxy-1-
Ethylene glycol monoalkyl ether (cellosolve) such as ethanol, 1-methoxy-2-propanol, 1-methoxy-2-butanol, 3-methoxy-1
-Butanol, 4-methoxy-1-butanol, 1-ethoxy-2-propanol and the like. Examples of keto alcohol-based compounds include diacetone alcohol.
Further, a fluorinated alcohol such as 2,2,3,3-tetrafluoropropanol can also be used.

Examples of the aliphatic hydrocarbon system are n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, dimethylcyclohexane, n-octane, iso-propylcyclohexane,
T-butylcyclohexane and the like are preferable, and among them, ethylcyclohexane and dimethylcyclohexane are preferable.

Further, examples of the ketone system include cyclohexanone.

In the present invention, an alkoxy alcohol type such as ethylene glycol monoalkyl ether type is particularly preferable, and among them, ethylene glycol monoethyl ether, 1-methoxy-2-propanol, 1-methoxy-
2-Butanol and the like are preferable, and a mixed solvent thereof is also preferable, and examples thereof include a combination of ethylene glycol monoethyl ether and 1-methoxy-2-butanol.

After the spin coating as described above, the coating film is dried if necessary. The thickness of the recording layer thus formed is appropriately set according to the desired reflectance and the like, but is usually 500 to 3000 A, and more preferably about 1000 to 3000 A.

The pigment content in the coating solution is preferably 2-10 wt%. In addition to the above-mentioned stabilizer, the coating liquid may appropriately contain a binder, a dispersant and the like.

FIG. 2 shows an example of the structure of an optical recording disk having such a dye film as a recording layer on a substrate. FIG. 2 is a partial sectional view. The optical recording disc 1 shown in FIG. 2 is a contact type optical recording disc which has a reflective layer in close contact with the recording layer and which is capable of reproduction in accordance with the CD standard. As shown, the optical recording disc 1 is
Recording layer 3 containing a dye as a main component on the surface of the substrate 2
And has a reflective layer 4 and a protective film 5 in close contact with the recording layer 3.

The substrate 2 has a disk shape, and in order to enable recording and reproduction from the back side of the substrate 2,
Recording light and reproducing light (wavelength of 580 to 900 nm, especially laser light of wavelength of 580 to 680 nm and wavelength of 77)
0-900nm semiconductor laser light, especially 635nm,
It is preferable to use a resin or glass that is substantially transparent (preferably a transmittance of 88% or more) for 650 nm and 780 nm. The size is 64 to 20 in diameter.
The thickness is about 0 mm and the thickness is about 1.2 mm.

Grooves 23 for tracking are formed on the surface of the substrate 2 on which the recording layer 3 is formed, as shown in FIG.
The groove 23 is preferably a spiral continuous groove having a depth of 0.1 to 0.25 μm, a width of 0.35 to 0.50 μm, and a groove pitch of 1 to 1.7.
μm is preferred. With such a configuration of the groove, a good tracking signal can be obtained without lowering the reflection level of the groove portion.
In particular, it is important to regulate the groove width to 0.35 to 0.50 μm, and if the groove width is less than 0.35 μm, it is difficult to obtain a tracking signal of sufficient magnitude.
With a slight offset of tracking during recording,
Jitter tends to be large. On the other hand, if it exceeds 0.50 μm, waveform distortion of the reproduced signal is likely to occur, which causes an increase in cross stroke.

As the material of the substrate 2, it is preferable to use a resin, and various thermoplastic resins such as polycarbonate resin, acrylic resin, amorphous polyolefin, TPX, polystyrene resin are suitable. Then, the resin can be manufactured by a known method such as injection molding. The groove 23 is preferably formed when the substrate 2 is molded. The resin layer having the groove 23 may be formed by the 2P method or the like after the substrate 2 is manufactured. In some cases, a glass substrate may be used.

As shown in FIG. 2, the recording layer 3 provided on the substrate 2 is formed by using the above-mentioned dye-containing coating solution, preferably by spin coating, as described above. The spin coating may be performed under normal conditions, for example, by adjusting the number of revolutions from 500 to 5000 rpm from the inner circumference to the outer circumference.

The recording layer 3 thus formed has a dry film thickness of 500 to 3000 A (50 to 300 n).
m) is preferred. Outside this range, the reflectance decreases and it becomes difficult to perform reproduction in accordance with the CD standard. At this time, the film thickness of the recording layer 3 in the recording track in the groove 23 is 1000 A (100 nm) or more, particularly 1300
When it is set to ˜3000 A (130 to 300 nm), the degree of modulation becomes extremely large.

As shown in FIG. 2, on the recording layer 3,
The reflective layer 4 is provided by directly adhering. As the reflective layer 4, it is preferable to use a high reflectance metal or alloy such as Au, Cu, Al or CuAg. The reflective layer 4 preferably has a thickness of 500 A or more, and may be formed by vapor deposition, sputtering or the like. Although the upper limit of the thickness is not particularly limited, it is preferably about 1200 A or less in consideration of cost, production work time and the like. Thereby, the reflectance of the reflective layer 4 alone is 90% or more, and the reflectance of the unrecorded portion of the medium through the substrate is 60% or more, particularly 70% or more, especially at a wavelength of about 780 nm.

As shown in FIG. 2, on the reflective layer 4,
The protective film 5 is provided. The protective film 5 is made of various resin materials such as an ultraviolet curable resin, and is usually 0.5 to 100 μm.
The layer may be formed to a thickness of about m. The protective film 5 may be layered or sheet-shaped. The protective film 5 may be formed by a usual method such as spin coating, gravure coating, spray coating, or dipping.

To perform recording or additional recording on the optical recording disk 1 having such a structure, for example, 780 nm or 635 nm is used.
Recording light having a wavelength of nm or 650 nm is irradiated in a pulse shape through the substrate 2 to change the light reflectance of the irradiation portion. In addition,
When irradiated with recording light, the recording layer 3 absorbs the light and generates heat,
At the same time, the substrate 2 is also heated. As a result, in the vicinity of the interface between the substrate 2 and the recording layer 3, the material of the recording layer such as a dye is melted or decomposed, and pressure is applied to the interface between the recording layer 3 and the substrate 2 to deform the bottom and side walls of the groove. Sometimes. When recording, the substrate rotation linear velocity was 1.2 to 1.4 m / s.
The degree.

The optical recording medium of the present invention is not limited to the contact type optical recording disk as shown in the drawing, but may be any one as long as it has a recording layer containing a dye. Examples of such a material include an pit-formed optical recording disk having an air sandwich structure, and similar effects can be obtained by applying the present invention.

[0127]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention together with comparative examples.

Example 1 Polycarbonate was injection molded to have a diameter of 120 mm and a thickness of 1.
A 2 mm substrate was obtained. Grooves for tracking having a groove pitch of 1.6 μm, a groove width of 0.42 μm and a groove depth of 1550 A were formed on the recording layer formation surface of the substrate.

Next, a mixture of Dye A-1 and Dye B-1 in a weight ratio of 1: 1 was dissolved in ethyl cellosolve,
A dye coating solution having a dye content of 4 wt% was prepared, and a dye film was formed by spin coating using the dye coating liquid, which was used as a recording layer. The thickness of the recording layer (dry film thickness) is 15 in the groove.
00A, 1200A on average. Further, an Au reflection layer having a thickness of 85 nm is formed on the recording layer by a sputtering method,
On top of this, a protective film of ultraviolet curable acrylic resin (film thickness 5
μm) was formed. Thus, an optical recording disk as shown in FIG. 2 was obtained.

About this disk sample No. 1, 7
When the recording / reproducing characteristics were examined at a linear velocity of 1.4 m / s using a semiconductor laser of 80 nm, the optimum recording power was 7.3.
mW, the reflectance of the disc before recording was 70% or more, the modulation degree of the recording signal was 60% or more, and the reflectance (Rtop) of the recording signal was 65%. Therefore, it was found that the optical recording disk complies with the Orange Book standard.

Furthermore, the value recorded at 780 nm is 63
When the reproducing characteristics were examined at a linear velocity of 1.4 m / s using a semiconductor laser of 5 nm, the characteristics of a reflectance of 52% and a degree of modulation of 44% were obtained. Further, the error rate at that time was 10 pieces / s or less when measured according to the C1 error of the Orange Book standard. Therefore, it was found that what was recorded at 780 nm could be well reproduced at 635 nm.

Contrary to the above, when the recording and reproducing characteristics were examined at a linear velocity of 1.4 m / s using a laser beam of 635 nm, the optimum recording power was 5 mW, and the reflectance of the disc before recording was 55%, and the modulation of the recording signal is 45
% And Rtop was 53%. Therefore, it was found that good recording and reproduction were possible at 635 nm.

Furthermore, the value recorded at 635 nm is 780
When the reproducing characteristics were examined at a linear velocity of 1.4 m / s using a semiconductor laser of nm, the characteristics of Rtop was 66% and the degree of modulation was 70%, and the error rate was 10 pieces / s or less for C1 error. Therefore, it was found that the reproduction that satisfies the Orange Book standard can be performed.

As described above, the dye A-1 contains 78
The n and k at 0 nm were 2.2 and 0.08, respectively, and the absorption spectrum of the thin film had a λmax of 724 nm and a full width at half maximum of 130 nm. Further, n and k at 630 nm of dye B-1 (determined at a dye film thickness of 80 nm) were 2.3 and 0.03, respectively, and λmax was 570 nm.

Example 2 A disk was prepared and evaluated in the same manner as in Example 1 except that the dyes were A-2 and B-2 (weight ratio 7: 3), respectively. The thickness of the recording layer (dry film thickness) is 130 in the groove.
0A, 1000A on average.

For this disk sample, 780 nm
When the recording / reproducing characteristics were examined at a linear velocity of 1.2 m / s using the semiconductor laser of No. 6, the optimum recording power was 6.9 m / W, the reflectance was 70% or more, the modulation degree was 60% or more, and Rtop 65
%Met. Therefore, it was found that the optical recording disk complies with the Orange Book standard.

Further, when the reproducing characteristics were examined at a linear velocity of 1.2 m / s using a semiconductor laser of 650 nm, the characteristics of reflectance 45% and modulation degree 40% were obtained. Further, the error rate at that time was the same as that of the first embodiment. Therefore, it was found that what was recorded at 780 nm could be well reproduced at 650 nm.

Contrary to the above, when the recording and reproducing characteristics were examined at a linear velocity of 1.2 m / s using a laser beam of 650 nm, the optimum recording power was 5.3 mW, and the reflection of the disc before recording was The rate is 47%, and the modulation degree of the recording signal is 4
0% and Rtop were 45%. Therefore, it was found that good recording and reproduction were possible at 650 nm.

Further, the value recorded at 650 nm is 780
When the reproduction characteristics were examined at a linear velocity of 1.2 m / s using a semiconductor laser of nm, the characteristics of Rtop 67% and modulation degree 73% were obtained, and the error rate was 10 pieces / s or less for C1 error. , It was found that the reproduction that satisfies the Orange Book standard can be performed.

As described above, the dye A-2 contains 78
The n and k at 0 nm were 2.3 and 0.05, respectively, and the absorption spectrum of the thin film had a λmax of 715 nm and a full width at half maximum of 140 nm. Further, n and k at 650 nm of dye B-2 (determined at a dye film thickness of 75 nm) were 2.5 and 0.08, respectively, and λmax was 610 nm.

Example 3 A disk was prepared and evaluated in the same manner as in Example 1 except that the dyes were A-3 and B-3 (weight ratio 3: 7), respectively.
The recording layer thickness (dry film thickness) is 1500A in the groove.
The average was 1300A.

For this disk sample, 780 nm
Using a semiconductor laser of, recording at a linear velocity of 4.8 m / s and examining reproduction characteristics at 1.2 m / s, optimum recording power was 12 mW, reflectance was 70% or more, modulation degree was 60% or more, Rtop was 65%. Therefore, it was found that the optical recording disk complies with the Orange Book standard.

Further, when the reproducing characteristics were examined at a linear velocity of 1.2 m / s using a semiconductor laser of 635 nm, the characteristics of reflectance of 45% and modulation degree of 40% were obtained. Further, the error rate at that time was equivalent to that of the first embodiment. Therefore,
It was found that what was recorded at 780 nm could be sufficiently reproduced at 635 nm.

Contrary to the above, when the recording and reproducing characteristics were examined at a linear velocity of 1.2 m / s using a laser beam of 635 nm, the optimum recording power was 5.5 mW, and the reflection of the disc before recording was The rate is 48%, and the modulation of the recording signal is 4
0% and Rtop were 45%. Therefore, it was found that good recording and reproduction were possible at 635 nm.

Further, the value recorded at 635 nm is 780
When the reproducing characteristics were examined at a linear velocity of 1.2 m / s using a semiconductor laser of nm, the characteristics of Rtop 65% and modulation degree 63% were obtained, and the error rate was 10 pieces / s or less for C1 error. , It was found that the reproduction that satisfies the Orange Book standard can be performed.

As described above, the dye A-3 contains 78
The n and k at 0 nm are 2.4 and 0.10, respectively, and the absorption spectrum of the thin film has a λmax of 725 nm and a full width at half maximum of 125 nm. Further, n and k at 630 nm of Dye B-3 (determined at a dye film thickness of 80 nm) were each 2.
3, 0.05 and λmax was 575 nm.

Example 4 In Example 1, instead of Dye A-1, Dye A-
4, A-5, A-7, A-8, A-9, A-13, A-
When a disk sample was prepared in the same manner except that 27, A-28, and A-24 were used and evaluated in the same manner, the same result as the sample of Example 1 was obtained.

Example 5 Dye A-1 in place of Dye A-2 in Example 2
When a disk sample was prepared in the same manner as in Example 9 except that each of A and A-34 was used and evaluated in the same manner, the same result as the sample of Example 2 was obtained.

Example 6 In Example 3, instead of Dye A-3, Dye A-4,
A-5, A-7, A-8, A-9, A-13, A-2
A disk sample was prepared in the same manner as in Example 7, except that A, A-28, and A-24 were used, and the same evaluation was performed.

Comparative Example 1 A disk was prepared in the same manner as in Example 1 except that only the dye A-1 was used, and the characteristics were evaluated. The evaluation at 780 nm was the optimum recording power of 7 mW, and the reflectance was 72%, the modulation degree was 65%, and the Rtop was 67%. It was found that the optical recording disk complies with the Orange Book standard.

Next, evaluation at 635 nm was performed in the same manner as in Example 1. When the reproducing characteristics were examined at a linear velocity of 1.4 m / s, it was found that the reflectance was 20% and the modulation was 10%.
It was not possible to reproduce what was recorded in nm at 635 nm.

On the other hand, recording at 635 nm requires a recording power of 7
It was not possible to obtain a sufficient signal even with mW.

Comparative Example 2 A disk was prepared in the same manner as in Example 1 except that B-1 was used as the dye, and the characteristics were evaluated. The evaluation at 780 nm could not be performed because recording could not be performed even when a recording power of 12 mW was applied.

On the other hand, the recording / reproducing at 635 nm was almost the same as that of the disc sample of Example 1, but it was impossible to reproduce the recording at 635 nm at 780 nm.

Comparative Example 3 A disk was prepared in the same manner as in Example 1 except that the dye A-1 was changed to the following pentamethinecyanine dye C-1, and the characteristics were evaluated. At 780 nm, the optimum recording power was 6 mW, the reflectance was 68%, the modulation was 75%,
Rtop was 68%. It was found that the optical recording disk complies with the Orange Book standard.

Next, evaluation at 635 nm was performed in the same manner as in Example 1. When the reproduction characteristics were examined at a linear velocity of 1.4 m / s, the reflectance was 13% and it was impossible to read the signal.

On the other hand, when the recording / reproducing characteristics at 635 nm were examined at a linear velocity of 1.4 m / s, the recording power was 4 mW.
The reflectivity of the disk before recording was 15%, the modulation degree of the recording signal was 50%, and Rtop was 13%, indicating insufficient characteristics.

[0158]

Embedded image

The n and k of the pentamethinecyanine dye C-1 at 780 nm were 2.45 and 0.05 (determined in the same manner as above with a dye film thickness of 75 nm). The absorption spectrum of the thin film has a λmax of 702n.
The m and half-value width (determined in the same manner as above with a dye film thickness of 80 nm) were 185 nm.

Example 7 In Example 1, a mixture of the dye A-3 and the dye B-8 at a weight ratio of 3: 2 was dissolved in 1-methoxy-2-butanol to give a dye content of 2.3 wt. % Dye coating solution was prepared, a dye film was formed by spin coating using this, and an optical recording disk was obtained in the same manner except that this was used as a recording layer. Good results equivalent to or better than those of Example 1 were obtained. In addition, 63 of dye B-8
N and k at 0 nm (determined at a dye film thickness of 80 nm)
Were 2.45 and 0.09, respectively, and λmax was 582 nm.

Example 8 In Example 7, a mixture of Dye A-3 and Dye B-15 at a weight ratio of 3: 1 was dissolved in 1-methoxy-2-butanol to give a dye content of 2.2 wt. % Dye coating solution was prepared, a dye film was formed by spin coating using this, and an optical recording disk was obtained in the same manner except that this was used as a recording layer. Good results equivalent to or higher than those of Example 7 were obtained. In addition, the dye B-15 had better solubility than the dye B-8, and the coating film properties were better. In addition, n of dye B-15 at 630 nm
And k (determined at a dye film thickness of 80 nm) are 2.3 and
It was 0.02 and λmax was 570 nm.

Example 9 In each of Examples 7 and 8, the same procedure was performed except that a recording layer was formed by replacing 15% by weight of each of the dyes B-8 and B-15 with the following quencher Q-1. Get an optical recording disc,
When the characteristics were examined in the same manner, it was found that good results equivalent to those of Examples 7 and 8 were obtained and the light resistance was further improved.

[0163]

[Chemical 31]

Example 10 In Example 2, a mixture of Dye A-3 and Dye B-4 at a weight ratio of 1: 1 was dissolved in 1-methoxy-2-butanol to give a dye content of 2.5 wt. % Dye coating solution was prepared, a dye film was formed by spin coating using this, and an optical recording disk was obtained in the same manner except that this was used as a recording layer. Good results equivalent to or higher than those of Example 2 were obtained. In addition, 65 of dye B-4
N and k at 0 nm (determined at a dye film thickness of 80 nm)
Were 2.5 and 0.09, respectively, and λmax was 612 nm.

Example 11 A 1-methoxy-2-butanol dye coating solution having a dye content of 2.3 wt% in which Dye A-3 and Dye B-5 were mixed in a weight ratio of 2: 3 in Example 10 was used. An optical recording disk was obtained in the same manner except that a dye film for the recording layer was formed using
When the characteristics were examined in the same manner, good results equivalent to or higher than those in Example 10 were obtained. In addition, the dye B-5 had better solubility than the dye B-4, and the coating film properties were better. In addition, n and k of dye B-5 at 650 nm
(Determined at a dye film thickness of 80 nm) is 2.45 and 0.0, respectively.
9 and the λmax was 611 nm.

Example 12 In Example 10, a 1-methoxy-2-butanol dye coating solution having a dye content of 3 wt% in which Dye A-3 and Dye B-6 were mixed in a weight ratio of 3: 2 was used. An optical recording disk was obtained in the same manner as above except that the dye film for the recording layer was formed, and the characteristics were examined in the same manner. The dye B-6 had better solubility than the dye B-4, and the coating film properties were better. The n and k of the dye B-6 at 650 nm (obtained at a dye film thickness of 80 nm) were 2.45 and 0.08, respectively, and the λmax was 614 nm.

Example 13 A 1-methoxy-2-butanol dye coating solution having a dye content of 2 wt% in which Dye A-3 and Dye B-7 were mixed in a weight ratio of 1: 1 was used in Example 10. An optical recording disk was obtained in the same manner except that the dye film for the recording layer was formed, and the characteristics were examined in the same manner. As a result, good results equivalent to or better than those of Example 10 were obtained. In addition, the dye B-7 had better solubility than the dye B-4, and the coating film properties were better. The n and k of the dye B-7 at 650 nm (determined at a dye film thickness of 80 nm) were 2.40 and 0.09, respectively, and the λmax was 612 nm.

Example 14 In each of Examples 10 to 13, dyes B-4 and B-
An optical recording disk was obtained in the same manner except that 30 wt% of each of the dyes 5, B-6 and B-7 was replaced with the same quencher Q-1 as in Example 9 to form a dye film for the recording layer. Similarly, the characteristics were examined. As a result, it was found that good results equivalent to those of the respective examples were obtained and the light resistance was further improved.

[0169]

According to the present invention, in the conventional wavelength range of about 780 nm, the reflectance is 65% or more, the modulation degree is 60% or more, and the R
A medium having a top of 65% or more is obtained, these characteristic values satisfy the Orange Book standard, and further, in the short wavelength region (630
It is possible to obtain an optical recording medium compatible with two wavelengths capable of recording and reproducing even at a wavelength of about nm to 680 nm.

[Brief description of drawings]

FIG. 1 is a graph illustrating a method of obtaining a half width of an absorption spectrum of a thin film of a phthalocyanine dye according to the present invention.

FIG. 2 is a partial sectional view showing an example of the optical recording disk of the present invention.

[Explanation of symbols]

 1 Optical Recording Disk 2 Substrate 23 Groove 3 Recording Layer 4 Reflective Layer 5 Protective Film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriyoshi Nanba 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDC Corporation

Claims (14)

[Claims] 1. An optical recording medium having a recording layer and a reflective layer on a substrate, wherein the recording layer has a real part n of complex refractive index at 780 nm of 1.
8 to 2.8, the imaginary part k is 0.15 or less, the absorption spectrum of the thin film has a full width at half maximum of 170 nm or less, and the real part n of the complex refractive index at 630 nm or 650 nm is 1.
An optical recording medium containing 8 to 2.8 and a dye B having an imaginary part k of 0.2 or less. 2. The optical recording medium according to claim 1, wherein the dye A is a phthalocyanine dye represented by the following formula (I). Embedded image [In Formula (I), M represents a central atom. X ₁ , X
₂ , X ₃ and X ₄ each represent a halogen atom, which may be the same or different. p1, p2,
p3 and p4 are each 0 or an integer of 1 to 4,
1 + p2 + p3 + p4 is 0 to 15. Y ₁ , Y ₂ ,
Y ₃ and Y ₄ each represent an oxygen atom or a sulfur atom,
These may be the same or different. Z ₁ , Z
₂ , Z ₃ and Z ₄ each represent an alkyl group having 4 or more carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group, which may be the same or different. q1, q2, q3 and q4 are each 0 or 1-4.
Which are not simultaneously 0, and q
1 + q2 + q3 + q4 is 1 to 8. ] 3. The optical recording medium according to claim 2, wherein the bonding positions of the phthalocyanine ring of Y ₁ , Y ₂ , Y ₃ and Y ₄ are the 3-position and / or the 6-position. 4. The optical recording medium according to claim ₂ , wherein each of Z ₁ , Z ₂ , Z ₃ and Z ₄ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group. 5. The alicyclic hydrocarbon group or aromatic hydrocarbon group represented by Z ₁ , Z ₂ , Z ₃ and Z ₄ is Y
The optical recording medium according to claim 4, which has a substituent at a position adjacent to each bonding position with ₁ , Y ₂ , Y ₃ and Y ₄ . 6. The optical recording medium according to claim 1, wherein the dye B is a trimethine cyanine dye represented by the following formula (II). Embedded image [In the formula (II), Q ₁ and Q ₂ represent a group of atoms necessary for completing a heterocycle with a carbon atom and a nitrogen atom, respectively, and the heterocyclic skeleton completed by Q ₁ or Q ₂ may be the same. It may be different. R ₁ and R ₂ each represent an aliphatic hydrocarbon group, which may be the same or different. R ₃ represents a hydrogen atom or a monovalent substituent. X ⁻ represents a monovalent anion. ] 7. The trimethine indolenine cyanine dye represented by the following formula (III):
Optical recording medium. Embedded image [In the formula (III), Q ₃ and Q ₄ each represent an atomic group necessary for completing an indolenine ring or a benzoindolenine ring together with a pyrrole ring, and the rings completed by Q ₃ or Q ₄ are the same. It may be different. R ₃
Represents a hydrogen atom or a monovalent substituent. R ₄ and R ₅
Each represents an alkyl group. X ⁻ represents a monovalent anion. ] 8. Q ₃ or Q ₄ together with the pyrrole ring
One of the rings completed in 1. is an indolenine ring, the other is a benzoindolenine ring, and the position at which the benzene ring of this benzoindolenine ring is fused to the indolenine ring is the indolenine ring. The optical recording medium according to claim 7, which is the fourth and fifth positions. 9. A hydrogen atom at the 5-position of the indolenine ring,
The optical recording medium according to claim 8, which has a halogen atom or an alkyl group. 10. Q ₃ or Q together with the pyrrole ring
Both of the rings completed in ₄ are benzoindolenine rings, and the positions where the benzene ring of the benzoindolenine ring is fused to the indolenine ring are the 4th and 5th positions of the indolenine ring. 7. Optical recording medium of 7. 11. The optical recording medium according to claim 7, wherein R ₄ and / or R ₅ is an alkoxyalkyl group. 12. The ratio of the dye A to the dye B in the recording layer, the dye A / dye B being 80/20 by weight.
The optical recording medium according to claim 1, which is 20/80. 13. The optical recording medium according to claim 1, wherein the recording layer is formed using a coating solution containing a dye A and a dye B, and the coating solvent is an alkoxy alcohol. 14. A singlet oxygen quencher is used as a stabilizer together with the trimethine cyanine dye.
The optical recording medium of any one of 13 to 13.