JPH07287871A - Optical information recording medium - Google Patents

Abstract

(57) [Summary] [Structure] In a read-only optical information recording medium comprising a reflective layer 3 formed on a transparent substrate 1 having irregularities corresponding to information signals, a dye material is used as the reflective layer. A dye-containing layer containing a polymer material as a main component and a titanium coupling agent added thereto is used. [Effect] An optical information recording medium using such a dye-containing layer as a reflecting layer can perform signal reproduction by a recording / reproducing apparatus for a low-reflectance medium such as a magneto-optical disk and has scratch resistance. Excellent, and good reproduction characteristics can be maintained even if there is some contact with foreign matter. Further, even when the formed dye-containing layer is dissolved again and reused, reproduction characteristics and scratch resistance characteristics equivalent to those of the original dye-containing layer can be reproduced. Therefore, it greatly contributes to the improvement of the practicality of the optical information recording medium and the reduction of the manufacturing cost.

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,
In particular, the present invention relates to a read-only optical information recording medium capable of reproducing a signal by a recording / reproducing device for a magneto-optical recording medium.

[0002]

2. Description of the Related Art As optical information media, compact discs (CD) for audio, laser disc discs (LD) for video and the like have already been widely spread. These compact discs and laser discs have a reflective layer and, if necessary, a protective layer provided on a substrate on which pits corresponding to information signals have been formed in a concavo-convex shape in advance, and are used for recording information signals. This is a read-only type optical disc that is only played back. The reflective layer has Al, A
A material having a high reflectance such as u, that is, a low absorptivity is used.

On the other hand, in recent years, unlike the above-mentioned read-only type optical disc, a magneto-optical disc is being developed as an optical information recording medium capable of writing and erasing information. This magneto-optical disk has a recording magnetic layer (for example, a rare earth-transition metal alloy amorphous thin film such as TbFeCo) which has an easy axis of magnetization in the direction perpendicular to the film surface and has a large magneto-optical effect on a substrate.
The recording portion is formed by laminating a reflective layer and a dielectric layer. As such a magneto-optical disk, a small-diameter magneto-optical disk (so-called mini disk) having a diameter of 64 mm has begun to be popularized in a form housed in a cartridge.

By the way, it is preferable that the read-only optical disk can be played back by a magneto-optical disk recording / playback apparatus as well, in order to enhance the spread and practicality of both the read-only optical disk and the magneto-optical disk system. I can say.
However, in a read-only type optical disc having a reflection layer such as an Al film or an Au film, the reflectance for laser light is 70% or more, which is significantly higher than the reflectance of a magneto-optical disc of 15 to 25%. A signal cannot be reproduced by a recording / reproducing device for a magneto-optical disk.

Therefore, in a read-only type optical disc, A
Attempts have been made to use a dye-containing layer made of a dye material and a polymer material as a reflective layer instead of the l film or Au film. The dye-containing layer can adjust the reflectance within the range of 15 to 25%, which is the same as the magneto-optical disk, by controlling the optical constant, the film thickness and the like, and is compatible with the magneto-optical disk.

[0006]

However, the dye-containing layer composed of the dye material and the polymer material has low scratch resistance,
It may be worn or scratched by some contact.

In an optical disc having a dye-containing layer as a reflection layer, read light is emitted from the substrate / dye-containing layer interface or the dye-containing layer /
Since signal reproduction is performed by utilizing the multiple reflections at the air interface to cause multiple interference, if the dye-containing layer is scratched or abraded as described above, the multiple interference of light is disturbed and the signal reproduction is performed. Will result in trouble.

Further, in the case of reusing an optical disc that is no longer needed for the purpose of cost reduction, the dye-containing layer made of a dye material and a polymer material is not dissolved in a solvent once it is cured. It is difficult to re-collect the composition because it becomes difficult. Further, even if the dye-containing layer composition was recovered from the optical disc, it was confirmed that the reflective layer formed by reusing it had inferior signal characteristics and scratch resistance characteristics to the original reflective layer. There is.

Therefore, the present invention has been proposed in view of such conventional circumstances, and it is possible to reproduce a signal by a recording / reproducing apparatus for a low reflectance medium such as a magneto-optical disk. Another object of the present invention is to provide an optical information recording medium which has excellent scratch resistance and can be reused.

[0010]

In order to achieve the above-mentioned object, the optical information recording medium of the present invention is mainly composed of a dye material and a polymer material on a transparent substrate on which irregularities corresponding to information signals are formed. An optical information recording medium having a reflective layer having a reflectance of 15 to 25% is characterized in that a titanium coupling agent is added to the reflective layer.

Further, the titanium coupling agent is added to the reflective layer in a ratio of 7 to 10% by weight based on the polymer material.

As shown in FIG. 1, an optical information recording medium to which the present invention is applied has concave pit portions 2a and convex land portions 2b corresponding to information signals, guide grooves, and address code pits. The dye-containing layer 3 having a reflectance of 15 to 25% is formed as a reflective layer on the substrate 1.

In the optical information recording medium having such a structure, the reading light LB emitted from the substrate 1 side is reflected at the substrate 1 / dye-containing layer 3 interface and the dye-containing layer 3 / air interface, respectively, to cause multiple interference. The signal is reproduced by using.
Therefore, the scratch resistance of the dye-containing layer 3 is low, and when the dye-containing layer 3 is scratched or abraded due to contact with a foreign substance, the multiple interference of the light is disturbed and the signal reproduction is hindered. .

In the present invention, as the reflection layer of the optical information recording medium having the above-mentioned structure, the dye-containing layer 3 is mainly composed of a dye material and a polymer material, to which a titanium coupling agent is added.
To use.

The dye-containing layer 3 having such a composition has improved scratch resistance due to the addition of the titanium coupling agent, and scratches and abrasion are less likely to occur. Therefore, under normal usage conditions, good multiplex interference of light is not disturbed, and good reproduction characteristics are maintained.

Moreover, the dye-containing layer 3 formed by containing the titanium coupling agent is soluble in the solvent, and the composition can be recovered. In addition, the dye-containing layer 3 reformed using the recovered composition is the original dye-containing layer 3
Reproduces the reproduction characteristics and scratch resistance comparable to those of. Therefore, after it is no longer needed, it can be reused, which greatly contributes to the reduction of the manufacturing cost of the optical information recording medium.

Any known titanium coupling agent can be used as the titanium coupling agent added to the dye-containing layer 3.
In particular, the titanium coupling agents shown in Chemical formula 1, Chemical formula 2, and Chemical formula 3 are preferable.

[0018]

[Chemical 1]

[0019]

[Chemical 2]

[0020]

[Chemical 3]

It is desirable that these titanium coupling agents be added so as to be 7 to 10% by weight with respect to the polymer material. If the addition amount of the titanium coupling agent is less than 7% by weight of the polymer material, the effect is insufficient and the scratch resistance of the dye-containing layer 3 cannot be sufficiently improved.
On the contrary, when the amount of titanium coupling agent added is more than 10% by weight of the polymer material, the addition of titanium coupling agent rather deteriorates the scratch resistance of the dye-containing layer 3.

As described above, in the present invention, the dye-containing layer 3 to which the titanium coupling agent is added is used as the reflective layer, and the reflectance of the dye-containing layer 3 is regulated to 15 to 25%.
This has a reflectance of 15 to 25% like that of a magneto-optical disk.
This is to enable signal reproduction by the recording / reproducing apparatus for the medium.

Therefore, the types and mixing ratios of the dye material and the polymer material contained in the dye-containing layer 3 are selected according to this reflectance range. Here, when selecting the materials and the mixing ratio, it is desirable to set the real part n of the complex refractive index of the dye-containing layer 3 to 1.84 or more. In the dye-containing layer 3 having a real part n of the complex refractive index of 1.84 or more, the reflectance can be set to 15 to 25% only by adjusting the film thickness within a practical range, and the film forming conditions can be easily set. Is.

As the dye material, whether it is an organic dye or an inorganic dye, the reflectance of the reflective layer can be set within the above range, and preferably the real part n of the complex refractive index of the dye-containing layer 3 is 1.84. Any of the above can be used. For example, examples of the organic dye include cyanine dyes such as NK529 (trade name, manufactured by Japan Photosensitive Dye Company) shown in Chemical formula 4 and SRC-8 (trade name, manufactured by Sony Corporation) shown in Chemical formula 5.

[0025]

[Chemical 4]

[0026]

[Chemical 5]

The polymer material is preferably selected in consideration of compatibility with the dye material and scratch resistance of the dye-containing layer 3, and the silicone varnish represented by Chemical formula 6 is preferable.

[0028]

[Chemical 6]

Further, a light stabilizer may be added to the dye-containing layer 3 for the purpose of preventing photobleaching of the dye material. As the light stabilizer, those having an electron donating property such as amines, materials having an energy level lower than the energy level of the excited state of the dye material such as nickel complex, and the like are used.

As the transparent substrate on which the reflective layer as described above is formed, those used in ordinary optical information recording media can be used. For example, glass, polycarbonate (PC), polyethylene terephthalate (PET). ) And the like.

[0031]

In an optical information recording medium in which a reflective layer is formed on a transparent substrate on which irregularities corresponding to information signals are formed, a dye material and a polymer material are mainly used as the reflective layer, and the reflectance is 15 to When the 25% dye-containing layer 3 is used, signal reproduction can be performed by a recording / reproducing apparatus for a medium having a reflectance of 15 to 25% such as a magneto-optical disk.

If a titanium coupling agent is further added to the dye-containing layer 3 to be the reflection layer, scratch resistance is improved,
Even if there is some contact with foreign matter, the reproduction characteristics are maintained well.

The dye-containing layer 3 containing the titanium coupling agent is soluble in a solvent, and the dye-containing layer 3 formed by using the dye solution prepared by re-dissolving the solvent is the original dye-containing layer. Reproduces reproduction characteristics and scratch resistance comparable to those of 3. Therefore, it can be reused after it is no longer needed.

[0034]

EXAMPLES Preferred examples of the present invention will be described based on experimental results.

Example 1-1 First, a dye material, a polymer material, a titanium coupling agent and an optical stabilizer were used, and a dye material: polymer material: titanium coupling agent: light stabilizer = 2: 2: 0. A dye solution was prepared by dissolving it in a solvent at a ratio of 0.2: 0.2. The following materials were used for the dye material, polymer material, titanium coupling agent, light stabilizer and solvent.

Dye material: Cyanine dye having an indoline ring (Nippon Photosensitive Dye Company, trade name NK529) Polymer material: Silicone varnish (Shin-Etsu Silicone Company)
Product name KR311) Titanium coupling agent: TOT (product name manufactured by Nippon Soda Co., Ltd.) Light stabilizer: Singlet oxygen quencher (product name IRG003 manufactured by Nippon Kayaku Co., Ltd.) Solvent: 3-hydroxy-3-methyl-2 -Butanone (manufactured by Tokyo Chemical Industry Co., Ltd.) The chemical formulas of cyanine dye, silicone varnish, titanium coupling agent and singlet oxygen quencher are shown in Chemical formulas 7 to 10, respectively.

[0037]

[Chemical 7]

[0038]

[Chemical 8]

[0039]

[Chemical 9]

[0040]

[Chemical 10]

The dye solution thus prepared was directly spin-coated on a substrate having pits cut beforehand to prepare a sample medium. Also, for a dye solution obtained by repeating drying and dissolution at room temperature 1 to 4 times,
Similarly, a substrate on which pits were cut was spin-coated to prepare a sample medium.

Then, the signal characteristics and the scratch resistance of these sample media were examined. The signal characteristics are the signal modulation degree I ₁₁
/ I _TOP was evaluated. Note that the signal modulation I ₁₁ / I _{TO P,} which is the ratio of reflected light I ₁₁ of the pit portion of the reflected light amount I _TOP and the maximum length of the land portion. Further, the scratch resistance was evaluated by incorporating the sample media into a cartridge for a mini disk, performing a shaking test, and visually observing the presence or absence of scratches after the shaking test.

Table 1 shows the examination results of the signal modulation degree I ₁₁ / I _TOP and the presence or absence of scratches after the shaking test.

Example 1-2 A dye solution was prepared in the same manner as in Example 1-1, except that TC-100 (trade name, manufactured by Matsumoto Pharmaceutical Co., Ltd.) was used as the titanium coupling agent. Alternatively, after drying and dissolution were repeated a predetermined number of times, spin coating was performed on the substrate with the pits cut to prepare a sample medium. T used as titanium coupling agent
The chemical formula of C-100 is shown in Chemical formula 11.

[0045]

[Chemical 11]

Then, the signal characteristics and scratch resistance of each of the prepared sample media were examined. The results are shown in Table 2.

Examples 1-3 T-50 (manufactured by Nippon Soda Co., Ltd.) as a titanium coupling agent
A dye solution was prepared in the same manner as in Example 1-1 except that (trade name) was used, and the dye solution was spin-coated on a substrate having pits cut as it was or after repeating drying and dissolution a predetermined number of times. Coated to prepare a sample medium. T-5 used as titanium coupling agent
The chemical formula of 0 is shown in Chemical formula 12.

[0048]

[Chemical 12]

Then, the signal characteristics and scratch resistance of each of the prepared sample media were examined. The results are shown in Table 3.

Comparative Example 1-1 A dye solution is prepared by dissolving a dye material, a polymer material and a light stabilizer in a solvent at a ratio of dye material: polymer material: light stabilizer = 2: 2: 0.2. Was prepared. The dye material, polymer material and optical stabilizer are the same as those used in Example 1-1. Then, in the same manner as in Example 1-1, the prepared dye solution was used as it was, or after drying and dissolution were repeated a predetermined number of times, spin coating was performed on the substrate with the pits cut to prepare sample media.
The signal characteristics and scratch resistance of each of the prepared sample media were examined. The results are shown in Table 4.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

[Table 4]

As can be seen by comparing Tables 1 to 3 with Table 4, in Examples 1-1 to 1-3 in which the titanium coupling agent was added to the dye solution, the dyes obtained by repeating dry dissolution a plurality of times were used. Even when the solution is used, a medium having the same signal characteristics and scratch resistance as when the dye solution that has not been dried and dissolved is used as it is. On the other hand, Comparative Example 1 in which no titanium coupling agent was added to the dye solution
In No. 1, the use of the dye solution that has been dry-dissolved provides only a medium having inferior signal characteristics and scratch resistance as compared with the case of using a dye solution that has not been dry-dissolved.

From this, it was found that the addition of the titanium coupling agent is effective in suppressing the deterioration of the characteristics of the dye-containing layer due to dry dissolution, and enables reuse of the dye-containing layer. . In addition, Example 1-1 to Example 1-
The signal modulation degrees I ₁₁ / I _TOP of the sample media prepared in Example 3 and Comparative Example 1-1 all meet the standard of signal modulation degrees in the minidisk system.

Example 2-1 A dye solution was prepared in the same manner as in Example 1-1 except that the addition amount of TOT was changed, and the dye solution was spin-coated as it was on a substrate having pits cut. Then, a sample medium was prepared. Then, the created sample medium was incorporated into an MD cartridge and a shaking test was conducted to examine the scratch occurrence rate.

FIG. 2 shows the relationship between the amount of TOT added and the rate of occurrence of scratches. In addition, in FIG. 2, the addition amount of TOT is shown by weight% with respect to the polymer material.

Example 2-2 Example 1 except that the amount of TC-100 added was changed.
-2, a dye solution is prepared in the same manner as in -2, and this dye solution is
A sample medium was prepared by directly spin-coating on a substrate with pits cut. Then, the created sample medium was incorporated into an MD cartridge and a shaking test was conducted to examine the scratch occurrence rate.

The relationship between the amount of TC-100 added and the rate of scratches is shown in FIG. In addition, the addition amount of TC-100 in FIG.
It is shown in% by weight with respect to the polymer material.

Example 2-3 Example 1-3 except that the amount of T-50 added is changed.
A dye solution was prepared in the same manner as above, and the dye solution was spin-coated on a substrate having pits cut as it was to prepare a sample medium. Then, the created sample medium was incorporated into an MD cartridge and a shaking test was conducted to examine the scratch occurrence rate.

FIG. 4 shows the relationship between the amount of T-50 added and the incidence of scratches.
Shown in. In addition, in FIG. 4, the addition amount of T-50 was shown by weight% with respect to the polymer material.

Referring to FIGS. 2 to 4, the occurrence rate of scratches on the medium is
Titanium coupling agent TOT, TC-100, T
It changes depending on the added amount of -50. From this,
It can be seen that the scratch resistance of the medium can be controlled by adding these titanium coupling agents. And, in the case of any titanium coupling agent, it is 7 to
By adding it in the range of 10% by weight, the scratch occurrence rate of the medium is reduced
It has been found that the scratch resistance can be improved and the scratch resistance can be improved.

[0064]

As is apparent from the above description, the optical information recording medium of the present invention is mainly composed of a pigment material and a polymer material and is reflected on a transparent substrate on which irregularities corresponding to information signals are formed. A reflective layer having a rate of 15 to 25% is formed,
Since the titanium coupling agent is added to the reflective layer, it is possible to perform signal reproduction by a recording / reproducing apparatus intended for a low-reflectance medium such as a magneto-optical disk, and at the same time, it is excellent in scratch resistance, Even if there is some contact, good reproduction characteristics can be maintained. Further, even when the formed dye-containing layer is dissolved again and reused, reproduction characteristics and scratch resistance characteristics equivalent to those of the original dye-containing layer can be reproduced. Therefore, it greatly contributes to the improvement of the practicality of the optical information recording medium and the reduction of the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of essential parts showing a configuration example of an optical information recording medium to which the present invention is applied.

FIG. 2 is a characteristic diagram showing a relationship between the amount of TOT added and the rate of occurrence of scratches.

FIG. 3 is a characteristic diagram showing the relationship between the amount of TC-100 added and the rate of scratches.

FIG. 4 is a characteristic diagram showing the relationship between the amount of T-50 added and the scratch occurrence rate.

[Explanation of symbols]

 1 substrate 2a pit part 2b land part 3 reflective layer

Claims (2)

[Claims] 1. An optical information recording medium comprising a transparent substrate, on which irregularities corresponding to information signals are formed, and a reflective layer, which is mainly composed of a dye material and a polymer material, and has a reflectance of 15 to 25%. An optical information recording medium, wherein a titanium coupling agent is added to the reflective layer. 2. The optical information recording medium according to claim 1, wherein the titanium coupling agent is added to the reflective layer in a ratio of 7 to 10% by weight based on the polymer material.