JPH11129626A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive to improve the environmental resistance, C/N characteristics and reading light characteristics of a medium by a method wherein an upper thin layer having a heat conductivity higher than that of a recording layer is provided on the recording layer including a specified indole-based cyanine coloring matter and, at the same time, a cavity-like recording pit is formed in the recording layer. SOLUTION: A recording layer 3 made of an indole-based cyanine coloring matter represented by the formula, in which (T) is a carbon chain for constituting a methine chain or a C3-C17 straight chain or a multi-membered ring and a hydrogen atom connecting to a carbon atom may well be converted with a halogen atom, A and A' respectively represent aromatic rings, which are the same as, or different from, each other and a hydrogent atom connecting to the carbon atom may well be converted with -I, -Br, -Cl, -Cn H2n+1 (n=1-22), -CH3 , is formed on a board 1. An upper thin layer 4 having a high heat conductivity such as a layer made of aluminum, copper, gold or the like is formed on the recording layer. As a result, neither adhesion nor accumulation of dust in a recording pit occurs, resulting in allowing to improve the environmental resistance of a medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium such as an optical disk, and more particularly to an optical information recording medium having a recording layer made of an organic dye and suitable for a write-once (WO) type optical disk. is there

[0002]

2. Description of the Related Art At present, compact discs (CDs) are widely used for music reproduction, but these are dedicated to reproduction, and are so-called direct read-after-write (DRA).
W) Without the function, the user cannot freely record and edit. So CD with DRAW function
The emergence of is desired. In addition, it is expected that an inexpensive optical disk having a DRAW function will be realized for optical disks other than CDs.

[0003]

As an optical recording material having a DRAW function, a perforated optical information recording medium is known. In this optical information recording medium, as shown in FIGS. 16 and 17, a recording layer 22 is formed on a transparent substrate 21, and when the recording layer 22 is irradiated with a laser, the irradiated recording layer 22 is partially irradiated. Upon melting, the thickness of the recording layer 22 is reduced only at that portion, or the substrate 21 is exposed to become recording pits 23 (see FIG. 17). At the time of reproduction, since the reflectance differs only in the recording pit 23, the signal can be read as a signal.

However, in this optical information recording medium,
As shown in FIG. 17, since the recording pit 23 has an open hole shape, dust or the like adheres and accumulates on the recording pit 23, causing an error. Furthermore, the pit ends are likely to be uneven, which causes a decrease in C / N. Further, when the read light is repeatedly irradiated many times, the pit shape changes, thereby causing a pit error.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide an optical information recording medium having excellent environmental resistance, C / N characteristics and read light resistance.

[0006]

According to a first aspect of the present invention, there is provided a light-emitting device comprising an optically transparent substrate and a recording layer formed on the substrate and having a higher refractive index than the substrate. In the information recording medium, the recording layer contains an indole cyanine dye having the following general structural formula, and an upper thin layer having a higher thermal conductivity than the recording layer is provided on the recording layer. In which hollow recording pits are formed.

[0007] General structural formula

[0008]

Embedded image

In the formula

[0010]

Is a carbon chain for constituting a methine chain and C ₃
~ C ₁₇ linear or multiple

A hydrogen atom consisting of a member ring and attached to a carbon element is a halogen atom,

[0012]

Embedded image

(R ″ may be substituted by a C ₁ -C ₆ linear or aromatic ring).

A and A 'may be the same or different;
Each represents an aromatic ring, a hydrogen atom with a carbon atom, -I, -Br, -Cl, -C n H 2n + 1 (n = 1~2
2), - OCH _3,

[0015]

Embedded image

, -NO ₂ ,

[0017]

Embedded image

(

[0019]

Embedded image

May be substituted with a linear hydrocarbon or an aromatic ring).

B and B 'may be the same or different;
-O-, -S-, -Se-, -CH = CH-, or

[0022]

Embedded image

(

[0024]

Embedded image

Are CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H
A C ₁ -C ₄ alkyl group such as ₉ ).

R and R ′ may be the same or different;
Represents a C ₁ -C ₂₂ alkyl group, which may be substituted with a sulfonyl group or a carboxyl group.

X is I, Cl, PF ₆ , ClO ₄ , SC
It represents an anion such as N, CF ₃ SO ₃ , BF _{4 and the} like.

M and n are each 0 or an integer of 1 to 3, and have a relationship of m + n ≦ 3.

According to a second aspect of the present invention, there is provided an optical information recording medium having an optically transparent substrate and a recording layer formed on the substrate and having a higher refractive index than the substrate. The recording layer contains an indole-based cyanine dye having the following general structural formula, an upper thin layer having higher thermal conductivity than the recording layer is provided on the recording layer, and the heat is applied between the recording layer and the substrate. A lower thin layer made of a material having low conductivity is provided, and hollow recording pits are formed in the recording layer.

General structural formula

[0031]

Embedded image

In the equation

[0033]

Embedded image

Is a carbon chain for forming a methine chain,
A hydrogen atom attached to a carbon element, which is a straight-chain or multi-membered ring of ₃ to ₁₇ carbon atoms, is a halogen atom,

[0035]

Embedded image

(R ″ may be substituted with a C _{1 to} C ₆ linear or aromatic ring).

A and A 'may be the same or different;
Each represents an aromatic ring, a hydrogen atom with a carbon atom, -I, -Br, -Cl, -C n H 2n + 1 (n = 1~2
2), - OCH _3,

[0038]

Embedded image

, -NO ₂ ,

[0040]

Embedded image

(

[0042]

Embedded image

May be substituted with a linear hydrocarbon or an aromatic ring).

B and B 'may be the same or different;
-O-, -S-, -Se-, -CH = CH-, or

[0045]

Embedded image

(

[0047]

Embedded image

Are CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H
A C ₁ -C ₄ alkyl group such as ₉ ).

R and R ′ may be the same or different;
Represents a C ₁ -C ₂₂ alkyl group, which may be substituted with a sulfonyl group or a carboxyl group.

X is I, Cl, PF ₆ , ClO ₄ , SC
It represents an anion such as N, CF ₃ SO ₃ , BF _{4 and the} like.

M and n are each 0 or an integer of 1 to 3, and have a relationship of m + n ≦ 3.

According to a third aspect of the present invention, there is provided an optical information recording medium comprising: an optically transparent substrate; and a recording layer formed on the substrate and having a higher refractive index than the substrate. At least a lower thin layer and an upper thin layer are provided sandwiching the recording layer, and the recording layer contains an indole cyanine dye having the following general structural formula, and is more thermally deformed than the lower thin layer and the upper thin layer. It is characterized in that it is a layer that is easy.

General structural formula

[0054]

Embedded image

In the formula,

[0056]

Embedded image

Is a carbon chain for constituting a methine chain,
A hydrogen atom attached to a carbon element, which is a straight-chain or multi-membered ring of ₃ to ₁₇ carbon atoms, is a halogen atom,

[0058]

Embedded image

(R ″ may be substituted with a C _{1 to} C ₆ linear or aromatic ring).

A and A ′ may be the same or different,
Each represents an aromatic ring, a hydrogen atom with a carbon atom, -I, -Br, -Cl, -C n H 2n + 1 (n = 1~2
2), - OCH _3,

[0061]

Embedded image

, -NO ₂ ,

[0063]

Embedded image

(

[0065]

Embedded image

May be substituted with a linear hydrocarbon or an aromatic ring).

B and B ′ may be the same or different,
-O-, -S-, -Se-, -CH = CH-, or

[0068]

Embedded image

(

[0070]

Embedded image

Are CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H
A C ₁ -C ₄ alkyl group such as ₉ ).

R and R ′ may be the same or different;
Represents a C ₁ -C ₂₂ alkyl group, which may be substituted with a sulfonyl group or a carboxyl group.

X is I, Cl, PF ₆ , ClO ₄ , SC
It represents an anion such as N, CF ₃ SO ₃ , BF _{4 and the} like.

M and n are each 0 or an integer of 1 to 3, and have a relationship of m + n ≦ 3.

[0075]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, since recording pits are hollow, no dust adheres or accumulates in the recording pits unlike conventional hole-shaped recording pits, and is environmentally resistant. Excellent in nature. The recording layer containing the indole cyanine dye paired with the counter ion as described above is easier to locally melt, evaporate, and sublimate than the recording layer made of another material.

Further, since an upper thin layer having a higher thermal conductivity than the recording layer is provided on the recording layer, heat radiation is good when forming the recording pit, and the size of the recording pit can be controlled. Easy. Further, since the recording layer is sandwiched between the upper thin layer and the lower thin layer to form a sandwich structure, a change in pit shape due to read light is small, and pit errors can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a double-sided air sandwich type optical disc according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part of the optical disc.

In these figures, reference numeral 1 denotes a disk-shaped substrate made of an optically transparent material, for example, polycarbonate, polymethyl methacrylate, polymethyl pentene,
A transparent resin material such as epoxy or a transparent ceramic such as glass can be used. In this embodiment, a polycarbonate substrate is used. 1a is a center hole of the substrate 1.

Reference numeral 2 denotes a lower thin layer formed on the substrate 1, which is a wavelength 780 of a semiconductor laser used for recording and reproduction.
It is composed of, for example, a phthalocyanine dye, silicon dioxide, squarylium, etc., which have a low absorption rate at around nm or 830 nm, are thermally stable, and have a lower thermal conductivity than metals.

Reference numeral 3 denotes a recording layer, which is composed of an indole cyanine dye having the following general structural formula.

General structural formula

[0082]

Embedded image

In the formula,

[0084]

Embedded image

Is a carbon chain for constituting a methine chain,
A hydrogen atom attached to a carbon element, which is a straight-chain or multi-membered ring of ₃ to ₁₇ carbon atoms, is a halogen atom,

[0086]

Embedded image

(R ″ may be substituted with a C _{1 to} C ₆ linear or aromatic ring).

A and A ′ may be the same or different,
Each represents an aromatic ring, a hydrogen atom with a carbon atom, -I, -Br, -Cl, -C n H 2n + 1 (n = 1~2
2), - OCH _3,

[0089]

Embedded image

, -NO ₂ ,

[0091]

Embedded image

(

[0093]

Embedded image

May be substituted with a linear hydrocarbon or an aromatic ring).

B and B ′ may be the same or different,
-O-, -S-, -Se-, -CH = CH-, or

[0096]

Embedded image

(

[0098]

Embedded image

Are CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H
A C ₁ -C ₄ alkyl group such as ₉ ).

R and R ′ may be the same or different;
Represents a C ₁ -C ₂₂ alkyl group, which may be substituted with a sulfonyl group or a carboxyl group.

X is I, Cl, PF ₆ , ClO ₄ , SC
It represents an anion such as N, CF ₃ SO ₃ , BF _{4 and the} like.

M and n are each 0 or an integer of 1 to 3, and have a relationship of m + n ≦ 3.

FIG. 3 is a view showing a typical example of Τ in the above general structural formula, and other examples may be used. FIG. 4 is a view showing a typical example of A and A 'in the above general structural formula. 5 to 12
FIG. 3 is a diagram showing specific examples of various indole cyanine dyes that can be used.

The concentration of the dye or dye composition at the time of forming the recording layer is preferably from 0.4 to 20% by weight. If it exceeds 20% by weight, the final thickness of the recording layer becomes too large, and the formation of cavities during recording does not proceed well. On the other hand, when the concentration is 0.4
When the content is lower than the weight percentage, defects such as pinholes are generated in the recording layer. The lower thin layer 2 and the recording layer 3 can be uniformly formed by spin coating with good mass productivity.

Referring back to FIG. 2, reference numeral 4 denotes an upper thin layer formed on the recording layer 3. The upper thin layer 4 is made of a material having a high thermal conductivity such as aluminum, copper, gold or an alloy containing them, and is thermally stable and rich in ductility, as shown in FIG. Extends along the shape of the cavity 5 formed in the middle of the recording layer 3 and swells to the opposite side of the recording layer 3 to maintain the swelling state. The upper thin layer 4 is formed to a predetermined thickness by, for example, vapor deposition, sputtering, ion plating, or the like.

In recording a signal, a laser beam is irradiated in a spot shape from the substrate 1 side to the recording layer 3 in FIGS. The recording conditions include, for example, a laser wavelength of 780 nm or 830 nm,
The linear velocity is 1.25 m / sec, and the recording power is 5 mW. By irradiating a laser beam in a spot like this,
The recording layer 3 is locally thermally melted. Simultaneous with this melting, there is slight evaporation and sublimation, and the generated vapor fills the signal cavity 5 formed by the melting, loses a refuge due to the presence of the upper thin layer 4, and loses heat due to the thermal energy of the irradiation beam. The soft upper thin layer 4 is expanded toward the side opposite to the substrate 1 as shown in FIG. Then, an appropriate pressure is generated in the closed cavity 5, and this pressure acts as a force for further expanding the cavity 5 and acts three-dimensionally. Therefore, the diffusion of the melt is promoted, and pits are formed more quickly and clearly.

As described above, the lower thin layer 2 has a low absorptance to laser light, is thermally stable, and has a lower thermal conductivity than metal, so that the heat accumulated in the recording layer 3 Is prevented from being dissipated to the substrate 1, and contributes to the formation of the cavity 5.

On the other hand, since the upper thin layer 4 is thermally stable and has high ductility, the film extends according to the shape of the cavity 5 when the recording pit is formed. In this case, the expanded shape can be maintained. Further, since the upper thin layer 4 is made of a material having a high thermal conductivity such as a metal, heat radiation is good when forming the recording pits, and the size of the recording pits can be easily controlled.

FIG. 14 and FIG. 15 are diagrams for explaining another embodiment of the present invention. In the case of this embodiment, the recording layer 3 is composed of a cyanine-based organic dye similarly to the above-described example, and the lower thin layer 2 and the upper thin layer 4 are made of a metal material having high ductility and malleability such as aluminum and gold. It is configured. Since both the lower thin layer 2 and the upper thin layer 4 are made of a metal material, those layers are formed by a sputtering method or a vapor deposition method.

Also in this embodiment, when the optical information recording medium is irradiated with a laser beam, only the thermally unstable recording layer 3 is thermally deformed as shown in FIG. Pits 5 are formed.

In the above embodiment, the case of a double-sided air sandwich type structure has been described. However, the present invention is not limited to this, and can be applied to other types of optical information recording media.

[0112]

According to the present invention, since the recording pits are hollow, no dust adheres or accumulates in the recording pits unlike the conventional hole-shaped recording pits, and the recording pit has improved environmental resistance. Are better. The recording layer containing the indole cyanine dye paired with the counter ion as described above is easier to locally melt, evaporate, and sublimate than the recording layer made of another material.

Further, since an upper thin layer having higher thermal conductivity than the recording layer is provided on the recording layer, heat radiation is good when forming the recording pits, and the size of the recording pits can be controlled. Easy. Further, since the recording layer is sandwiched between the upper thin layer and the lower thin layer to form a sandwich structure, a change in pit shape due to read light is small, and pit errors can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a double-sided air sandwich type optical disc according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the optical disc.

FIG. 3 is a diagram showing a typical example of Τ in the general structural formula.

FIG. 4 is a diagram showing a typical example of A and A ′ in the general structural formula.

FIG. 5 is a diagram showing specific examples of various indole cyanine dyes.

FIG. 6 is a diagram showing specific examples of various indole cyanine dyes.

FIG. 7 is a diagram showing specific examples of various indole cyanine dyes.

FIG. 8 is a diagram showing specific examples of various indole cyanine dyes.

FIG. 9 is a diagram showing specific examples of various indole-based cyanine dyes.

FIG. 10 is a view showing specific examples of various indole cyanine dyes.

FIG. 11 is a view showing specific examples of various indole cyanine dyes.

FIG. 12 is a diagram showing specific examples of various indole cyanine dyes.

FIG. 13 is a schematic diagram of a recording pit.

FIG. 14 is an enlarged sectional view of a main part of an optical disc according to another embodiment of the present invention.

FIG. 15 is a schematic diagram of recording pits on the optical disc.

FIG. 16 is an enlarged sectional view of a main part of a conventional optical disk.

FIG. 17 is a schematic diagram of recording pits on the optical disc.

[Description of Signs] 1 Substrate 2 Lower thin layer 3 Recording layer 4 Upper thin layer 5 Cavity

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masashi Suenaga 1-1-88 Ushitora, Ibaraki-shi, Osaka Inside Hitachi Maxell Co., Ltd.

Claims (4)

[Claims] 1. An optical information recording medium having an optically transparent substrate and a recording layer formed on the substrate and having a higher refractive index than the substrate, wherein the recording layer has an indole type having the following general structural formula: Optical information recording comprising a cyanine dye, an upper thin layer having a higher thermal conductivity than the recording layer is provided on the recording layer, and hollow recording pits are formed in the recording layer. Medium. General structural formula Embedded image in the formula is a carbon chain for constituting a methine chain and C ₃
~ C ₁₇ linear or multiple A hydrogen atom consisting of a membered ring and attached to the carbon element may be substituted with a halogen atom, wherein R ″ is a C ₁ -C ₆ linear or aromatic ring. A and A ′ may be the same or different, each represents an aromatic ring, and the hydrogen atom attached to the carbon atom is represented by -I,-
_{Br, -Cl, -C n H 2n} + 1 (n = 1~22), - OC
H ₃ , embedded image, —NO ₂ , Embedded image ( May be substituted with a linear hydrocarbon or an aromatic ring). B and B 'may be the same or different, and -O-,
-S-, -Se-, -CH = CH-, or ( Represents C ₁ such as CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉
ＣC ₄ alkyl group). R and R ′ may be the same or different, represent a C ₁ -C ₂₂ alkyl group, and may be substituted with a sulfonyl group or a carboxyl group. X represents I, Cl, PF ₆ , ClO ₄ , SCN,
Represents anions such as CF ₃ SO ₃ and BF ₄ . m and n are each an integer of 0 or 1 to 3, and m +
It has a relationship of n ≦ 3. 2. An optical information recording medium having an optically transparent substrate and a recording layer formed on the substrate and having a higher refractive index than the substrate, wherein the recording layer has an indole type having the following general structural formula: An upper thin layer containing a cyanine dye and having a higher thermal conductivity than the recording layer on the recording layer, and a lower thin layer made of a material having a low thermal conductivity between the recording layer and the substrate. And an optical information recording medium, wherein a hollow recording pit is formed in the recording layer. General structural formula In the formula, Is a carbon chain for constituting a methine chain, which is a C ₃ -C ₁₇ linear or multi-membered ring, wherein the hydrogen atom attached to the carbon element is a halogen atom, (R ″ may be substituted with a C _{1 to} C ₆ linear or aromatic ring.) A and A ′ may be the same or different;
Each represents an aromatic ring, a hydrogen atom with a carbon atom, -I, -Br, -Cl, -C n H 2n + 1 (n = 1~2
2), -OCH ₃ , , -NO ₂ , ( May be substituted with a linear hydrocarbon or an aromatic ring). B and B 'may be the same or different, and -O-,
-S-, -Se-, -CH = CH-, or ( Represents C ₁ such as CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉
ＣC ₄ alkyl group). R and R ′ may be the same or different, represent a C ₁ -C ₂₂ alkyl group, and may be substituted with a sulfonyl group or a carboxyl group. X represents I, Cl, PF ₆ , ClO ₄ , SCN,
Represents anions such as CF ₃ SO ₃ and BF ₄ . m and n are each an integer of 0 or 1 to 3, and m +
It has a relationship of n ≦ 3. 3. The method according to claim 1, wherein
The optical information recording medium, wherein the upper thin layer is made of a metal material. 4. An optical information recording medium having an optically transparent substrate and a recording layer formed on the substrate and having a higher refractive index than the substrate, wherein at least a lower thin layer and an upper thin layer sandwich the recording layer. Wherein the recording layer contains an indole cyanine dye having the following general structural formula, and is a layer that is more easily thermally deformed than the lower thin layer and the upper thin layer. Medium. General structural formula In the formula, Is a carbon chain for constituting a methine chain, which is a C ₃ -C ₁₇ linear or multi-membered ring, wherein the hydrogen atom attached to the carbon element is a halogen atom, (R ″ may be substituted with a C _{1 to} C ₆ linear or aromatic ring.) A and A ′ may be the same or different;
Each represents an aromatic ring, a hydrogen atom with a carbon atom, -I, -Br, -Cl, -C n H 2n + 1 (n = 1~2
2), -OCH ₃ , , -NO ₂ , ( May be substituted with a linear hydrocarbon or an aromatic ring). B and B 'may be the same or different, and -O-,
-S-, -Se-, -CH = CH-, or ( Represents C ₁ such as CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉
ＣC ₄ alkyl group). R and R ′ may be the same or different, represent a C ₁ -C ₂₂ alkyl group, and may be substituted with a sulfonyl group or a carboxyl group. X represents I, Cl, PF ₆ , ClO ₄ , SCN,
Represents anions such as CF ₃ SO ₃ and BF ₄ . m and n are each an integer of 0 or 1 to 3, and m +
It has a relationship of n ≦ 3.