JPH09202052A - Optical information recording medium - Google Patents

Abstract

(57) Abstract: An optical information recording medium excellent in light resistance and storage stability applicable to a high density optical disc system using a semiconductor laser having an oscillation wavelength shorter than a conventional wavelength band, and a current system. The present invention provides an optical information recording medium which can be recorded and reproduced by the above method and can be reproduced only in the next-generation high-density optical disc system. A recording layer containing at least one compound represented by the following general formula (I) as a main component or the compound and the recording layer
A recording layer made of a mixture with an organic dye having a maximum wavelength of 80 to 750 nm is provided. Embedded image

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium, and more particularly, to an information recording medium by irradiating a light beam.
The present invention relates to an optical information recording medium capable of recording / reproducing information and additionally recording by causing optical changes such as transmittance and reflectance in a recording material.

[0002]

2. Description of the Related Art The current write-once optical disk system (WO
RM, CD-R), the oscillation wavelength of the laser used is 770.
nm to 790 nm, and the recording medium records at the above wavelength,
It is configured to be able to reproduce. In the future, it is inevitable that the recording medium will have a large capacity as the amount of information increases, and accordingly, it is also essential to shorten the laser wavelength used for recording and reproduction. As a write-once optical disc for data, many proposals have been made using a cyanine dye or a phthalocyanine dye as a recording material.
At present, a recording material which has excellent storage stability and is recordable and reproducible by an optical pickup using a laser of 700 nm or less has not yet been developed.

The current CD-R disk system is also configured so that recording and reproduction can be performed at a laser oscillation wavelength of 770 nm to 790 nm. In this system, similarly to the above, it is essential to increase the capacity and shorten the laser wavelength. In this respect, current CDs and CD-ROMs are coated with Al on the irregularities of the substrate itself, and the wavelength dependence of the reflectance of Al is small. Therefore, even if the laser wavelength is shortened in the future, reproduction will not be possible. It is possible. However, the CD
-R uses a dye having a maximum absorption wavelength at 690 nm to 730 nm in the recording layer, and has a value of 7 from the optical constant and film thickness constitution.
Since it is set to obtain a high reflectance in the range of 70 nm to 790 nm, the reflectance is extremely low in the wavelength range of 700 nm or less, and it cannot cope with the shortening of the laser wavelength.
The information recorded and reproduced by the D-R system cannot be reproduced by the future system. Until now CD-R
As such, many proposals have been made using a cyanine dye / metal reflection layer, a phthalocyanine dye, an azo metal chelate dye, or the like as a recording material, but a solution to such a point has not yet been found.

[0004]

Therefore, the present invention has been made in view of the above situation, and is a high density optical disc using a semiconductor laser having an oscillation wavelength in a shorter wavelength than the conventional system. A CD that can be applied to a system and is provided with a recording material for an optical information recording medium that is excellent in light resistance and storage stability, and that can be recorded and reproduced by the current system and can be reproduced by a next-generation high-density optical disc system. -The purpose is to provide a recording material for R medium.

[0005]

As a result of intensive studies, the present inventors have made a high-density optical disk system using a semiconductor laser having an oscillation wavelength of 700 nm or less by using a recording layer containing a specific dye as a main component. It was found that this compound is applicable, and further, by using this compound in combination with an organic dye currently used as a recording material for CD-R, 7
They have found that it is possible to obtain a high reflectance even in a wavelength range of 00 nm or less, and have completed the present invention.

That is, according to the present invention, firstly, a recording layer is provided directly on a substrate or via an undercoat layer, and if necessary, a metal reflection layer and a protective layer are provided thereon. An optical information recording medium, wherein the recording layer contains at least one of compounds represented by the following general formulas (I), (II) and (III) as a main component. Will be provided. General formula (I)

Embedded image (In the above formula, R ^{1 to} R ⁷ and X respectively represent the following: R ^{1 to} R ³ : hydrogen atom or optionally substituted carbon number 1
To 6 alkyl groups, which may be the same or different. R ^{4 to} R ⁷ : hydrogen atom or optionally substituted carbon number 1
To 12 alkyl groups, which may be the same or different. X: Acid anion. ) General formula (II)

Embedded image (In the above formula, R ^{11 to} R ¹⁵ , X and n represent the following respectively. R ^{11 to} R ¹³ : a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, each of which is R ¹⁴ and R ^{15 are a} halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, an alkylthio group, an aryl group or a dialkylamino group, which may be the same or different. X: acid anion n: 1 or 2.) General formula (III)

Embedded image (In the above formula, R ^{21 to} R ²⁵ , X, Y, m and n respectively represent the following: R ²¹ : an alkyl group having 1 to 12 carbon atoms; R ²² , R ²³ : hydrogen atom or substituted R ^{24 is a} halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, an alkylthio group, an aryl group or a dialkylamino group. R ²⁵ : hydrogen atom, halogen atom, nitro group, hydroxy group, substituted or unsubstituted alkyl group, alkoxy group, alkylthio group or carboxylic acid ester residue X: acid anion Y: oxygen atom, sulfur atom or- C (R ²⁶ ) (R ²⁷ )
-Group. R ²⁶ , R ²⁷ : a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, which may be the same or different. m: an integer of 0 to 4. n: 1 or 2. ) Secondly, in the optical information recording medium described in the first,
The recording layer has the general formulas (I), (II) and (III)
Of at least one compound represented by
There is provided an optical information recording medium comprising a mixed layer with an organic dye having a maximum absorption wavelength at 50 nm.
Third, in the optical information recording medium described in the second,
Provided is an optical information recording medium, wherein the organic dye having the maximum absorption wavelength in the range of 680 nm to 750 nm is at least one of pentamethine cyanine dye, phthalocyanine dye and azo metal chelate dye. Fourthly, there is provided an optical information recording medium as described in the above first or second, in which the metal of the metal reflective layer contains at least one of gold, silver and aluminum as a main component. It Fifth, in the optical information recording medium described in the first or second, there is provided an optical information recording medium in which the protective layer is made of an ultraviolet curable resin.

The optical information recording medium of the present invention is provided with a recording layer containing at least one of the compounds represented by the general formulas (I), (II) and (III) as a main component.
Recording and reproduction is possible with laser light in the wavelength range of 0 nm or less,
Moreover, it is excellent in light resistance and storage stability, and further, at least one compound represented by the general formulas (I), (II) and (III), and an organic dye having a maximum absorption wavelength at 680 to 750 nm. Since the recording layer containing a mixture of the above as a main component is provided, it can be used as a CD-R in the current system, and even if it becomes a next-generation high-density optical disc system, it is possible to reproduce the described information. Will be things.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The optical information recording medium of the present invention is characterized in that the recording layer contains at least one of the compounds represented by the general formulas (I), (II) and (III) as a main component. In the general formula (I), R ^{1 to} R ³ represent: a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms,
Each may be the same or different, and R ^{4 to} R ⁷
Represents a hydrogen atom or an optionally substituted alkyl group having 1 to 12 carbon atoms, which may be the same or different. In the general formula (II), R ^{11 to} R ¹³ represent a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, each of which may be the same or different,
R ¹⁴ and R ¹⁵ represent a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, an alkylthio group, an aryl group or a dialkylamino group, and they may be the same or different. In the general formula (III),
R ²¹ represents an alkyl group having 1 to 12 carbon atoms, and R ²² , R ^22
23 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, which may be the same or different, and R ²⁵ represents a hydrogen atom, a halogen atom, a nitro group, a hydroxy group, a substituted or unsubstituted group. Represents a substituted alkyl group, an alkoxy group, an alkylthio group or a carboxylic acid ester residue, and Y represents an oxygen atom, a sulfur atom or -C (R ²⁶ ).
Represents an (R ²⁷ ) -group. R ²⁶ and R ^{27 each} represent a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, which may be the same or different. Further, X common to the general formulas (I) to (III) represents an acid anion such as a halogen ion, a perhalogenate ion, an alkylsulfate anion, a PF ₆ anion, a BF ₄ anion, and a SbF ₆ anion. In addition, m represents an integer of 0 to 4 and n represents 1 or 2.

In the above general formula (I), when R ^{1 to} R ³ have more than 6 carbon atoms and R ^{4 to} R ⁷ have more than 12 carbon atoms, the stability (light resistance, storage stability) is extremely lowered. To do. In the general formula (II), when R ^{11 to} R ¹³ have more than 6 carbon atoms,
Stability (light resistance, storage stability) is extremely reduced. Further, in the general formula (III), when R ²¹ has more than 12 carbon atoms and R ²² , R ²³ , R ²⁶ or R ²⁷ has more than 6 carbon atoms,
Stability (light resistance, storage stability) is extremely reduced.

Specific examples of the compounds represented by the above general formulas (I), (II) and (III) are shown in Tables 1, 2 and 3.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

[Table 3]

In the recording layer, as described above, at least one of the compounds represented by the general formulas (I), (II) and (III) and an organic dye having a maximum absorption wavelength at 680 to 750 nm. CD-based recording and playback with the current system and playback only with the next-generation system by using a mixture of
It becomes an R recording medium. In this case, as the dye having the maximum absorption wavelength at 680 to 750 nm, pentamethine cyanine dye, phthalocyanine dye and azo metal chelate dye are preferable.

Preferred examples of pentamethine cyanine dyes include those represented by the following general formula (IV).

Embedded image In the formula, R ³¹ and R ³² are alkyl groups having 1 to 4 carbon atoms, R ³³ is a hydrogen atom, a methyl group or a phenyl group, R ^{34 to} R ³⁷ are alkyl groups having 1 to 2 carbon atoms, and X is an acid anion. Represent In addition,
The aromatic ring may be fused with another aromatic ring.

Preferred examples of the phthalocyanine dye include those represented by the following general formula (V-1) or (V-2).

Embedded image [In the formula, M is Al, Ga, In, Si, Ge or Sn.
Represents X may be the same or different from each other, and may have an alkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic residue which may have a substituent, Halogen atom, nitro group, cyano group, sulfonic acid group, -OR ⁴¹ , -SR ⁴² , -COOR ⁴³ , -NR
⁴⁴ R ⁴⁵ , -SO ₂ NR ⁴⁶ R ⁴⁷ , -CONR ⁴⁸ R ⁴⁹ , -C
_{^{H 2 NHCOCH 2 N 50 R 51}} , -NHCOR 52, -N = N
Represent R ⁵³ or -N = CHR ^54. R ⁴¹ , R ⁴² , R ⁴³ ,
R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ , R ⁴⁸ , R ⁴⁹ , R ⁵⁰ and R
^{51, which} may be the same or different from each other, represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an acyl group, a cycloalkyl group, or a polyether group; ⁴⁶ and R ⁴⁷ , R ⁴⁸ and R ⁴⁹ , or R ⁵⁰ and R ⁵¹ may form a 4- to 7-membered ring, and these 4- to 7-membered ring is a hetero atom such as a nitrogen atom. It may be a heterocycle containing atoms. R ⁵² , R ⁵³ and R ^{54, which} may be the same or different, each represents an alkyl group having a substituent, a cycloalkyl group or an aryl group. Z is a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group which may have a substituent, R ⁵⁵ , R ⁵⁶ , R ⁵⁷ , R ⁵⁸ , R ⁵⁹ and R ⁶⁰ may be the same or different and may have a substituent, an alkyl group, an aryl group, an acyl group, a cycloalkyl Represents a group, an alkoxy group, an aryloxy group, a polyether group, a hydroxyl group, or a halogen atom. W is O, S, Se
Or represents Te. k, l, m and n each independently represent an integer of 0-8. p represents 0 or 1. ]

[Chemical 6] [In the formula, each R ⁶¹ independently represents a secondary alkyl group having 3 to 20 carbon atoms, and M represents a divalent metal atom or an oxy metal. The substitution positions of the —OR ⁶¹ group are the 1 or 4, 5 or 8, 9 or 12 and 13 or 16 positions. ] The alkoxy phthalocyanine represented by these.

Preferred examples of the azo metal chelate dye include azo metal chelate compounds of an azo compound represented by the following general formula (VI) and a metal.

Embedded image In the formula, A represents a residue which forms a heterocyclic ring together with the carbon atom and the nitrogen atom to which it is bonded, and B represents an aromatic ring together with the two carbon atoms to which it is bonded. Or a residue forming a heterocyclic ring, and X represents a group having active hydrogen.

In the recording layer, not only the compounds represented by the general formulas (I) to (III) or the compound and the specific organic dye are mixed, but also the optical characteristics, recording sensitivity and signal characteristics are obtained. It is of course possible to mix or layer with other organic dyes and metals or metal compounds in order to improve the property. In this case, the organic dyes include polymethine dyes, naphthalocyanine dyes, phthalocyanine dyes, squarylium dyes, coroconium dyes, pyrylium dyes, naphthoquinone dyes, anthraquinone (indanthrene) dyes, xanthene dyes, triphenylmethane dyes, azulene dyes, tetrahydro dyes. Examples thereof include choline-based, phenanthrene-based, triphenothiazine-based dyes, and metal complex compounds. Examples of metals and metal compounds include In, Te, and
Bi, In, Se, Sb, Ge, Sn, Al, Be, T
Examples thereof include eO ₂ , SnO, As, and the like, and each of them can be used in the form of dispersion mixing or lamination. Furthermore, for the purpose of improving the properties, stabilizers (for example, transition metal complexes),
It can be used together with a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer and the like. A solvent casting method can be used as the film forming method, and the film thickness is 100Å to 5
μm, preferably 300 Å to 2 μm.

Next, the structure of the recording medium will be described. The structure of the recording medium of the present invention is as shown in FIGS. 1 to 4 as a write-once type optical disk for data, and a sandwich structure in which these two sheets are bonded together may be used. Also,
The structure shown in FIGS. 3 and 4 can be applied to the write-once compact disc. That is, in FIG. 1, the recording layer 2 is provided on the substrate 1, and the metal reflective layer 5 is provided thereon. FIG.
Is an undercoat layer 3 between the substrate 1 and the recording layer 2 having the structure shown in FIG.
Is provided. FIG. 3 shows the metal reflection layer 5 having the structure shown in FIG.
A protective layer 4 is further provided on the above. FIG.
2 has a structure in which a protective layer 4 is further provided on the metal reflection layer 5 having the structure shown in FIG.

Next, regarding each layer other than the recording layer constituting the recording medium of the present invention, necessary characteristics and examples of constituent materials will be described. <Substrate> A required characteristic of the substrate is that it must be transparent to the laser light used only when recording / reproducing is performed from the substrate side, and need not be transparent when performing recording from the recording layer side. As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, glass, ceramics or metal can be used. Note that a guide groove or guide pit for tracking, and a preformat such as an address signal may be formed on the surface of the substrate.

<Undercoat Layer> The undercoat layer is (a) improved in adhesiveness, (b) barrier for water or gas, (c) improved storage stability of the recording layer, and (d) improved reflectance. , (E) protection of the substrate from solvent, (f) formation of guide grooves, guide pits, preformats, etc. (A)
For the purpose of using a polymer material, for example, various polymer materials such as ionomer resin, polyamide resin, vinyl resin, natural resin, natural polymer, silicone, liquid rubber and silane coupling agent. Can
For the purposes of (b) and (c), in addition to the above polymeric materials, inorganic compounds such as SiO ₂ , MgF ₂ , SiO,
Metals or semi-metals such as TiO ₂ , ZnO, TiN, SiN, etc., for example Zn, Cu, Ni, Cr, Ge, Se, A
u, Ag, Al and the like can be used. Also,
For the purpose of (d), a metal such as Al or Ag, or an organic thin film having a metallic luster such as a methine dye,
A xanthene dye or the like can be used, and for the purposes of (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 1
0 μm is appropriate.

<Metal Reflective Layer> The reflective layer may be made of a metal or a semi-metal which has a high reflectance and is not easily corroded. Examples of the material include Au, Ag, Cu, Cr, Ni and Al. However, in terms of reflectance and productivity, Au, A
g and Al are most preferred. These metals and metalloids may be used alone or as two or more alloys. Examples of the film forming method include vapor deposition and sputtering.
The film thickness is 50 to 5000Å, preferably 100 to 3
000.

<Protective Layer, Substrate Surface Hard Coat Layer> The protective layer or the substrate surface hard coat layer (a) protects the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc. (b)
It is used for the purpose of improving the storage stability of the recording layer (reflection / absorption layer) and (c) improving the reflectance. For these purposes, the materials shown in the undercoat layer can be used. Further, SiO, SiO _2, etc. can be used as the inorganic material, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene,
Heat-softening or heat-melting resins such as polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying fat, rosin, etc. Can be used. Among the above materials, the most preferable material for the protective layer or the substrate surface hard coat layer is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is 0.01 to 30 μm, preferably 0.05 to 10 μm. In the present invention,
The undercoat layer, the protective layer, and the substrate surface hard coat layer, as in the case of the recording layer, a stabilizer, a dispersant, a flame retardant,
An antistatic agent, a surfactant, a plasticizer and the like can be contained.

[0024]

The present invention will be described below in detail with reference to examples.

Example 1 A compound specific example No. was formed on a substrate on which a guide groove having a depth of 1200Å, a half value width of 0.4 μm and a track pitch of 1.4 μm was formed on a PMMA plate having a thickness of 1.2 mm by a photopolymer. ． The 1,2-dichloroethane solution of No. 4 was applied to a spinner to form a recording layer having a thickness of 800 Å to obtain a recording medium.

Examples 2 to 4 Specific examples of compounds in Example 1 No. 4 instead of Compound No. 4 respectively. 8, No. 9 and No. 9 12
A recording medium was formed in the same manner as in Example 1 except that was used.

Comparative Example 1 Specific example No. of the compound in Example 1 A recording medium for comparison was formed in the same manner as in Example 1 except that the compound (formula VII) shown below was used instead of 4.

Embedded image

<Evaluation> The recording media of Examples 1 to 4 and Comparative Example 1 produced as described above were evaluated for reflectance and recording and reproducing characteristics including a light resistance test and a storage test. The results are shown in Table 4. <Measurement method> Recording conditions Laser oscillation wavelength: 680 nm Recording frequency: 1.25 MHz Recording linear velocity: 1.2 m / sec Reproduction conditions Laser oscillation wavelength: 680 nm Reproduction power: Continuous light of 0.25 to 03 mW Scanning band width: 30 KHz Light resistance Test conditions Light resistance test: 40,000 Lux, Xe light, 200 hours continuous irradiation Storage test: 85 ° C, 85% RH, 720 hours storage

[0029]

[Table 4]

Example 5 Depth of 1000 Å, Half-width of 0.4 μm, Pitch of 1.6 μm
On the 1.2 mm thick injection-molded polycarbonate substrate having the guide groove of Example, the compound No. 1, 2, 2, 3,
3-Tetrafluoropropanol solution is applied by spinner to form an organic dye layer with a thickness of 1600Å, then a reflective layer of gold with a thickness of 2000Å is formed by a sputtering method, and an acrylic photopolymer with a thickness of 2 μm is formed on the reflective layer. A layer was provided to make a recording medium.

Examples 6 and 7 Specific examples of compounds in Example 5 No. 1 instead of compound specific example No. 1. 6 and no. A recording medium was formed in the same manner as in Example 5 except that 16 was used.

Comparative Example 2 As the organic thin film in Example 5, the compound specific example No.
A recording medium for comparison was formed in the same manner as in Example 5 except that the compound represented by the formula (VII) was used in place of 1.

<Evaluation> The recording media of Examples 5 to 7 and Comparative Example 2 produced as described above were evaluated for reflectance and recording and reproducing characteristics. Table 5 shows the results
Shown in <Measurement method> A semiconductor laser having an oscillation wavelength of 680 nm and a beam diameter of 1.4 μm was recorded on this recording medium, and an EFM signal was recorded while tracking (linear velocity 1.4 m / sec).
The reproduced waveform was observed by reproducing with the continuous light of the same laser.

[0034]

[Table 5]

Example 8 Depth 1000Å, Half-Width Width 0.45 μm, Pitch 1.6 μ
m and a 1.2 mm thick injection-molded polycarbonate substrate having guide grooves, the compound represented by the formula (VII) and the compound No. 2 and 4 in a weight ratio (1/1)
A 2,3,3-tetrafluoropropanol solution is applied by spinner to form an organic dye layer with a thickness of 1600Å, then a gold and 2000Å reflective layer is formed by a sputtering method, and an acrylic photopolymer is applied on top of it. 2μ
A protective layer of m was provided to obtain a recording medium.

Examples 9 and 10 Specific examples of compounds in the recording layer of Example 8 4 instead of Compound No. 4 respectively. 8 and No. A recording medium was formed in the same manner as in Example 8 except that 9 was used.

Comparative Example 3 A recording medium for comparison was formed in the same manner as in Example 5 except that the compound represented by the following formula (VIII) was used as the organic thin film in Example 5.

Embedded image

<Evaluation> The recording media of Examples 8 to 10 and Comparative Example 3 manufactured as described above were evaluated for reflectance and recording and reproducing characteristics. Table 6 shows the results. <Measurement Method> An EFM signal was recorded while tracking using a semiconductor laser having an oscillation wavelength of 780 nm and a beam diameter of 1.6 μm on this recording medium (linear velocity 1.4 m / sec).
Same laser and oscillation wavelength 680nm, beam diameter 1.4μ
The reproduced waveform was observed by reproducing with continuous light of a semiconductor laser of m.

[0039]

[Table 6]

[0040]

According to the optical information recording medium of claim 1, since the recording layer containing at least one of the compounds represented by the general formulas (I), (II) and (III) as a main component is provided, 7
Recording and reproduction are possible with a laser beam in the wavelength range of 00 nm or less, and the light resistance and storage stability are excellent.

In the optical information recording medium of claim 2, the recording layer has at least one compound represented by the general formulas (I), (II) and (III) and a maximum absorption wavelength in the range of 680 nm to 750 nm. Since it is composed of a mixed layer with an organic dye, it can be used as a CD-R in the current system, and it becomes possible to reproduce recorded information even if it becomes a next-generation high-density optical disc system. .

The optical information recording medium according to claim 3 is the 680.
Since the organic dye having the maximum absorption wavelength in the range of nm to 750 nm is at least one of pentamethine cyanine dye, phthalocyanine dye and azo metal chelate dye, high-quality signal characteristics can be recorded.

In the optical information recording medium according to claim 4, since the metal of the metal reflection layer contains at least one of gold, silver and aluminum as a main component, it is possible to improve the productivity and the reflectivity of the CD. -R media conversion is possible.

In the optical information recording medium according to the fifth aspect, since the protective layer is made of the ultraviolet curable resin, it is possible to form the protective layer medium with good productivity.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a recording medium of the present invention.

FIG. 2 is a schematic sectional view showing another example of the recording medium of the present invention.

FIG. 3 is a schematic sectional view showing still another example of the recording medium of the present invention.

FIG. 4 is a schematic sectional view showing still another example of the recording medium of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording layer 3 Undercoat layer 4 Protective layer 5 Metal reflective layer

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yasunobu Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (5)

[Claims] 1. An optical information recording medium in which a recording layer is provided on a substrate directly or via an undercoating layer, and if necessary, a metal reflective layer and a protective layer are provided on the recording layer. An optical information recording medium containing at least one of the compounds represented by the following general formulas (I), (II) and (III) as a main component. General formula (I) (In the above formula, R ^{1 to} R ⁷ and X respectively represent the following: R ^{1 to} R ³ : hydrogen atom or optionally substituted carbon number 1
To 6 alkyl groups, which may be the same or different. R ^{4 to} R ⁷ : hydrogen atom or optionally substituted carbon number 1
To 12 alkyl groups, which may be the same or different. X: Acid anion. ) General formula (II): (In the above formula, R ^{11 to} R ¹⁵ , X and n represent the following respectively. R ^{11 to} R ¹³ : a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, each of which is R ¹⁴ and R ^{15 are a} halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, an alkylthio group, an aryl group or a dialkylamino group, which may be the same or different. X: acid anion, n: 1 or 2.) General formula (III) (In the above formula, R ^{21 to} R ²⁵ , X, Y, m and n respectively represent the following: R ²¹ : an alkyl group having 1 to 12 carbon atoms; R ²² , R ²³ : hydrogen atom or substituted R ^{24 is a} halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, an alkylthio group, an aryl group or a dialkylamino group. R ²⁵ : hydrogen atom, halogen atom, nitro group, hydroxy group, substituted or unsubstituted alkyl group, alkoxy group, alkylthio group or carboxylic acid ester residue X: acid anion Y: oxygen atom, sulfur atom or- C (R ²⁶ ) (R ²⁷ )
-Group. R ²⁶ , R ²⁷ : a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, which may be the same or different. m: an integer of 0 to 4. n: 1 or 2. ) 2. The recording layer comprises the general formulas (I) and (I
At least one compound represented by I) and (III),
2. The optical information recording medium according to claim 1, comprising a mixed layer with an organic dye having a maximum absorption wavelength in the range of 680 nm to 750 nm. 3. The optical information recording medium according to claim 2, wherein the organic dye having a maximum absorption wavelength in the range of 680 nm to 750 nm is at least one of pentamethine cyanine dye, phthalocyanine dye and azo metal chelate dye. 4. The optical information recording medium according to claim 1, wherein the metal of the metal reflective layer contains at least one of gold, silver and aluminum as a main component. 5. The optical information recording medium according to claim 1, wherein the protective layer is made of an ultraviolet curable resin.