JPH04131280A - Optical recording medium - Google Patents

Abstract

PURPOSE:To improve the adhesion between an org. dye recording layer and a metal reflecting layer and to enhance reliability by laminating a recording layer consisting of an org. dye and a nitrogen or sulfur-containing heterocyclic compound and a metal reflecting layer constituted of a lower layer part composed of Cu or Ag and an upper layer part based on Au to a transparent substrate. CONSTITUTION:In an optical recording medium constituted by laminating a recording layer 2 based on an org. dye and a metal reflecting layer to a transparent substrate 1, the recording layer 2 is constituted of 50-95wt.% of an org. dye and 5-50wt.% of a heterocyclic compound containing at least one element among nitrogen and sulfur. The metal reflecting layer is constituted of a lower layer part 3 composed of at least one kind of a metal selected from Cu and Ag and an upper layer part 4 based on Au. Further, a protective layer 5 composed of an ultraviolet curable resin may be further formed on the metal reflecting layer 4. The heterocyclic compound is easy to form a chelate compound along with Cu or Ag in general and it is considered that this action contributes to the development of adhesion. Therefore, sufficient recording reproduction characteristics are ensured and excellent durability can be kept even in the use as a single plate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical recording medium on which information is recorded and reproduced using light, particularly laser light.

[Prior Art] Optical recording media are manufactured by irradiating an optical recording layer formed on a substrate with a laser beam, so that the irradiated area undergoes thermal deformation, hole formation, layer change, etc., resulting in optical density changes (reflectance or transmittance). It is used to record information by generating changes in

Materials used for the optical recording layer include metals with low melting points such as tellurium and bismuth, as well as materials in the near-infrared region (wavelengths 700 to 900).
It is known that organic dyes having an absorption range in the range r+m), such as cyanine dyes, merocyanine dyes, and naphthoquinone dyes, are materials that exhibit good properties.

Advantages of using organic dyes as optical recording materials include that they are non-toxic, and that film formation costs can be reduced by forming films using spin cords.As a result of these advantages, they have recently become popular as optical recording layers. Organic dyes are increasingly being used.

On the other hand, it is difficult to obtain a high reflectance with a recording film made only of organic dyes, and in order to increase the reflectance, it is necessary to provide a reflective layer of metal such as aluminum or gold. In particular, with the spread of the compact disc system in recent years, there is a need for a high reflectivity write-once optical recording medium that is compatible with this system.
For this purpose, lamination of an organic dye film and a metal reflective film has become widely used.

[Problems to be Solved by the Invention] However, in general, metal reflective films such as ALAu have weak adhesion to organic dye films, and as a result, noise may increase due to partial peeling of the reflective film around recording bits.
During storage, a phenomenon occurred in which the reflective film peeled off and the disc was damaged, posing a serious problem in its reliability as a recording medium.

[Means for Solving the Problems] In view of these circumstances, the inventors of the present invention conducted extensive studies to develop a highly reliable recording medium with good adhesion between the organic dye recording layer and the metal reflective layer. As a result, we have completed the present invention.

That is, the present invention provides an optical recording medium in which a recording layer A containing an organic dye as a main component and a metal reflective layer B are laminated on a transparent substrate. Heterocyclic compounds 5 to 50 containing at least one of
% by weight, and the metal reflective layer B is made of a metal containing at least one selected from Cu and Ag;
This is an optical recording medium characterized in that it is composed of an upper layer mainly composed of.

The heterocyclic compound used as the recording layer of the present invention includes:
imidazoles, triazoles, tetrazoles, thiazoles, thiadiazoles, thiatriazoles,
There are triazinethiols, and examples include the following compounds.

Imidazole, IH-1,2,4-)riazole, benzotriazole, IH-tetrazole, 1,3-thiazole, 1. 2. 4-thiazoles 4H-1,2,3
, 4-thiatriazole, thiophene, 2-methylimidazole, 2-phenylimidazole, 2. 4. 6
-) dimercapto-1゜3.5-1 liazine, 2-dimethylamino-2゜4-dimercapto-1,3,5-) riazine, 6-[(2-methylimidazolyl)ethyl]-
2゜4-diamino-1,3,5-triazine, 1-phenyl-5-mercaptotetrazole, 1-methyl-5-
Mercaptotetrazole etc.

The composition ratio of the recording layer A of the present invention is as described above, but if the content of the heterocyclic compound is less than 5% by weight, the effect of improving adhesion is small, and if it exceeds 50% by weight, the content of the dye is Due to the insufficient amount, the absorption efficiency of laser light decreases, making it impossible to obtain sufficient recording sensitivity.

In addition, there are no particular restrictions on the organic dyes contained in Recording JiiA as long as they satisfy the optical properties described above, but preferable dyes in terms of optical properties and film properties include nyanine dyes, merocyanine dyes, naphthoquinone dyes, and phthalocyanine dyes. It is.

The above-mentioned laminated film is used as the metal reflective layer B of the present invention, and the lower layer is a single film of Cu or Ag, or if an alloy is used, the total content of Cu and Ag is 30 atoms. % or more, preferably 50 atom % or more. If it is less than 30 atom %, the effect of improving adhesion is small and sufficient adhesion cannot be obtained. on the other hand,
There are no particular restrictions on the composition other than Cu or Ag in the alloy, but metals with high reflectance such as AI are suitable. Note that the thickness of this lower layer portion is preferably in the range of 1 to 20n+n, more preferably 1 to 5 nm. By setting the film thickness of the lower layer within this range,
Recording layer A and metal reflective layer B without impairing the high reflectivity of the upper layer.
It is possible to improve the adhesion with.

For the upper layer of the metal reflective layer B, a film made of Au alone is used, or when an alloy film is used, the gold content is 50 atomic % or more,
Preferably, it needs to be 70 atom % or more. A
If the u content is less than 50 atomic %, sufficient reflectance cannot be obtained, and the effect of improving reflectance by installing a reflective film is small. There is no particular restriction as long as it is within the range that can be obtained.

The mechanism by which strong adhesion is obtained when recording layer A and metal reflective layer B are formed using the above materials is unknown, but heterocyclic compounds generally tend to form chelate compounds with Cu and Ag; It is thought that these effects contribute to the development of adhesion.

The optical recording medium of the present invention can be manufactured by laminating a recording layer A and a metal reflective layer B in this order on a transparent substrate. Although there are no particular restrictions on the method of forming each layer, it is economically most advantageous to form the recording layer A by a spin cord.

On the other hand, the metal reflective layer B can generally be formed by a vacuum deposition method, a sputtering method, or the like. In addition, metal reflective layer B
A protective layer such as an ultraviolet curing resin may be further formed thereon.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, in the examples and comparative examples, the recording layer was formed by a spin code method, the metal reflective layer was formed by a sputtering method,
All boards are 13oIII115 in diameter and 1°2wa in thickness.
Polycarbonate injection molded substrate (pitch 1.6μm)
, with a grip of width 0.6 μm) was used.

The durability of the produced optical recording medium was determined by measuring the C/N by recording and reproducing a single frequency signal, and then performing an accelerated deterioration test at 60°C and 90% RH to observe changes in the C/N of the recorded signal. was evaluated.

Evaluation of recording and playback characteristics is done using Parstic tester rDDU.
-100J (light source length: 7 g Onm, objective lens NA: 0.5).

The following compounds were used as the organic dye and heterocyclic compound.

CIO, - H3 C84 CIO, - C84 Example 1 80% by weight of the organic dye represented by formula (A) and 20% by weight of the compound represented by formula (1), 20% by volume of N,N-dimethylformamide, 100n by dispersing in a mixed solvent consisting of 80% by volume of 1-butanol and coating it on the substrate.
A film is formed to a thickness of +n, and then sputtering C is applied on top of it.
A film of 5 rv of u and a film of 50+v of Au were formed in this order.Finally, an ultraviolet curable resin was formed as a protective layer to a thickness of 10 μm, and then cured to obtain an optical recording medium.

A single frequency signal of 720 kHz is applied to this medium at a linear velocity of 1
, 3 Ih1s-, recorded under the condition of recording laser power of 6 mW, and reproducing the signal with reproduction laser power of 0.5 mW, the C/N was 52 dB, and this was further increased to 60 mW.
After accelerating for 500 hours at a temperature of 90% RH, the C/N was 49 dB when reproduced under the same conditions.

Example 2 By the same method as in Example 1, 100 n+a of a mixture consisting of 85% by weight of the dye of formula (A) and 15% by weight of the compound of formula (2), 10% by weight of Ag, and 40% by weight of Au were deposited on a substrate. weight m,
Films of ultraviolet curing resin were formed in order to have a thickness of 10 μm. This medium was recorded and reproduced under the same conditions as in Example 1.
The initial value of N was 54 dB, and it was 52 dB after acceleration for 500 hours at 60'C90%RH.

Example 3 By the same method as in Example 1, a mixture of 75% by weight of the dye of formula (B) and 25% by weight of the compound of formula (3) was coated on a substrate with 10 Or+m, an alloy of 30 atomic % of Cu and 70 atomic % of Ag. 7r++++, Au and 451111% ultraviolet curable resin were formed into films with a thickness of 10 μm in this order. When this medium was recorded and reproduced under the same conditions as in Example 1, the C/N was an initial value of 5.
1 (IB, 60℃90%RH 50dB after 500 hours acceleration
Met.

Example 4 By the same method as in Example 1, a mixture of 70% by weight of the dye of formula (B) and 30% by weight of the compound of formula (4) was deposited on a substrate to a thickness of 100 nm, and an alloy of 80 atomic % of Ag and 10 atomic % of AlO was deposited on a substrate. 5 nm, Au 45 nm, UV curing resin 1
Films were formed in order of thickness of 0 μm. When this medium was recorded and reproduced under the same conditions as Example 1, the C/N was an initial value of 52 (iB
, 51 dB after acceleration at 60° C., 90% RH, for 500 hours.

Example 5 By the same method as in Example 1, 1100 nm of a mixture consisting of 80% by weight of the dye of formula (A) and 20% by weight of the compound of formula (5), 5 nm of Cu, 30 atomic % of Cu + Au
60 atomic% alloy 451m5 UV curing resin 10μ
The films were formed in the order of thickness m. When this medium was recorded and reproduced under the same conditions as Example 1, the C/N was an initial value of 50 (IB, 6
It was 47 dB after acceleration for 500 hours at 0°C, 90% RH.

Example 6 By the same method as in Example 1, 1100 nm of a mixture consisting of 80% by weight of the dye of formula (B) and 20% by weight of the compound of formula (6), 5 nm of Ag, and 30 atomic % of Ag + Au were placed on a substrate.
45 weight m of 70 atom% alloy, 10 μm of ultraviolet curing resin
The films were formed in the order of thickness m. When this medium was recorded and reproduced under the same conditions as in Example 1, the C/N was an initial value of 53 dB and 60 dB.
It was 51 dB after acceleration for 500 hours at 90% RH.

Example 7 By the same method as in Example 1, a mixture of 75% by weight of the dye of formula (B) and 25% by weight of the compound of formula (7) was deposited on a substrate at 1100n, Cu at 3rrm, Ag at 50 atomic%+A
50 weight m of u50 atomic% alloy, 10 m of ultraviolet curing resin
The films were formed in the order of the thickness of the μ strip. When this medium was recorded and reproduced under the same conditions as in Example 1, the C/N was an initial value of 51 dB, 6
50 (IB) after acceleration at 0° C., 90% RH, and 500 hours.

Comparative Example 1 A dye of formula (A) was formed on a substrate to a thickness of 100 nm+m by the same method as in Example, and on top of that, 50 m of Au and 10 μm of ultraviolet curable resin were applied in Example. A film was formed in the same manner. When this medium was recorded and reproduced under the same conditions as in the example, the initial C/N was 52 dB, but the C/N was 6 dB.
35 dB when accelerated for 500 hours at 0°C and 90% RH.
It dropped to .

Comparative Example 2 A dye of formula (A) was formed on a substrate to a thickness of 10On+m by the same method as in Example, and Cu was deposited on it for 5 nm.
A film of 4,511 m of Au and a film of ultraviolet curing resin of 10 μm was formed in the same manner as in the example. When this medium was recorded and reproduced under the same conditions as in the example, the C/N was an initial value of 52 dB.
However, after accelerating for 500 hours at 60° C. and 90% RH, it decreased to 37 dB.

Comparative Example 3 Dye 8 of formula (A) was deposited on a substrate by the same method as in Example.
A mixture of 0% by weight and 20% by weight of compound (1) at 110%
A film was formed to a thickness of 0 nm, and thereon, a film of 50 rv of Au and a film of 10 rv of ultraviolet curable resin were formed in the same manner as in the example. When this medium was recorded and reproduced under the same conditions as in the example, the C/N was an initial value of 52 dB, but at 60°C90
When accelerated for 500 hours under the condition of %RH, it decreased to 40 dB.

Comparative Example 4 Dye 7 of formula (B) was applied on a substrate by the same method as in Example.
A mixture of 0% by weight and 30% by weight of the compound (2) was formed to a thickness of 10w+, and then Au was formed to a thickness of 50 nm and an ultraviolet curing resin was formed to a thickness of 10 μm in the same manner as in the example. did. When the medium was recorded and reproduced under the same conditions as in the example, the C/N was an initial value of 53 (IB), but at 60℃9
After accelerating for 500 hours under 0% RH conditions, it decreased to 38 dB.

Comparative Example 5 Dye 8 of formula (A) was deposited on a substrate by the same method as in Example.
110% of a mixture of 5% by weight and 15% by weight of compound (5)
A film was formed to a thickness of 0 nm, and thereon a film of 50 rv of Au and a film of 10 μm of an ultraviolet curable resin were formed in the same manner as in the example. When this medium was recorded and reproduced under the same conditions as in the example, the C/N was an initial value of 51 dB, but at 60°C, 90%
When accelerated for 500 hours under RH conditions, it decreased to 39 (IB).

Comparative Example 6 Dye 8 of formula (B) was applied on a substrate by the same method as in Example.
A mixture of 0% by weight and 20% by weight of compound (6) at 10O
A film was formed to a thickness of r+m, and thereon, a 50 nm thick Au film and a 10 μm thick ultraviolet curable resin film were sequentially formed in the same manner as in the example. When this medium was recorded and reproduced under the same conditions as in the example, the C/N was an initial value of 54 dB.
When accelerated for 500 hours under the condition of %RH, it decreased to 37 dB.

[Effects of the Invention] Since the optical recording medium of the present invention has sufficient recording and reproducing characteristics and excellent durability even when used as a single plate, it is expected that it will be widely used as a recording medium.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the optical recording medium of the present invention, in which 1 is a transparent substrate, 2 is a recording layer, 3 is a lower layer of a metal reflective layer, 4 is an upper layer of a metal reflective layer, and 5 is a protective layer. Patent Applicant: Mitsubishi Rayon Co., Ltd. Procedural Amendment H/1990/Yuhi Patent Application No. 2-254505 Patent Applicant: 2-3-19 Kyobashi, Chuo-ku, Tokyo Spontaneous Issue 5, Specification subject to amendment ``Claims'' and ``Issuance 1) Claims are amended as shown in the appendix. 2) ``Preferably 50 atomic % or more of "is necessary." is corrected to "preferably 50 atom % or more." 3) "The content is preferably 70 atom % or more" written in lines 16 to 17 of page 6 is corrected to "preferably the content is 70 atom % or more." 4) "Greep" stated in the 3rd line of the 8th Summer of the same is amended to "Group J." 5) The formula (B) stated in the 9th N of the same is amended as follows. CIO, - Claims [ 1) In an optical recording medium formed by laminating a recording layer A containing an organic dye as a main component and a metal antifouling layer B on a transparent substrate, the recording layer A contains 50 to 95% by weight of the organic dye and at least one of nitrogen or sulfur. Complex type 1 compound 5Ws containing species.Weight, CA 1.., Group 9 Reflective layer B is composed of a lower layer made of a metal containing at least one selected from Cu or Ag and an upper layer mainly made of Au. 2) The lower layer of the metal reflective layer B is made of Cu and/or Ag.
2. The optical recording medium according to claim 1, wherein the optical recording medium is a metal layer containing 30 atomic % or more of. 3) The optical recording medium according to claim 1, wherein the thickness of the lower layer of the metal reflective layer B is 1 to 200 nm. 4) The optical recording medium according to claim 1, wherein the upper layer of the metal reflective layer B is a metal layer containing 50 atomic % or more of Au. ” Procedural amendment 1990 February 1st, Q day 1, case indication CH3 CH3 Cl0. - Relationship to the case Patent applicant 2-3-19 Kyobashi, Chuo-ku, Tokyo, Voluntary 5, "Detailed description of the invention" column 6 of the specification to be amended, Contents of the amendment

Claims (1)

[Claims] 1) In an optical recording medium formed by laminating a recording layer A containing an organic dye as a main component and a metal reflective layer B on a transparent substrate, the recording layer A contains 50 to 95% by weight of the organic dye. The metal reflective layer B is composed of 5 to 50% by weight of a heterocyclic compound containing at least one kind of nitrogen or sulfur, and the lower layer part is made of a metal containing at least one kind selected from Cu or Ag, and the upper layer is mainly composed of Au. An optical recording medium comprising: 2) The optical recording medium according to claim 1, wherein the lower layer portion of the metal reflective layer B is a metal layer containing 30 atomic % or more of Cu or Ag. 3) The optical recording medium according to claim 1, wherein the thickness of the lower layer of the metal reflective layer B is 1 to 200 nm. 4) The optical recording medium according to claim 1, wherein the upper layer of the metal reflective layer B is a metal layer containing 50 atomic % or more of Au.