JPH07201074A - optical disk - Google Patents

Abstract

(57) [Summary] [Purpose] Many people can identify almost perfect golden color,
Moreover, an optical disc having an appearance whose color tone is maintained for a long time is provided at a low cost. A metal reflective layer 4 having a reflectance of 80% or more at a wavelength of 450 to 800 nm is provided on a transparent substrate 2, and a color tone control layer 6 containing a colorant is provided on the metal reflective layer 4, and a color tone control layer 6 is provided. When the light transmittance T (%) at the wavelength λ (nm) of 700 is 80 ≦ T when 700 ≦ λ ≦ 800, 30 ≦ T ≦ 90 when 600 ≦ λ ≦ 700, and T ≦ 60 when 450 ≦ λ ≦ 500 Is an optical disc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc.

[0002]

2. Description of the Related Art In a read-only optical disc such as a compact disc, a pit portion is provided on a transparent substrate, and a metal reflection layer such as Al or Au is provided on the pit portion. In addition, in a write-once type optical recording disc using an organic dye as a recording material, A is recorded on the recording layer.
A metal reflective layer made of a metal having a high reflectance such as u is provided. Further, in a magneto-optical disk, a metal reflective layer is usually provided on a recording layer via a dielectric film. A resin topcoat layer is usually provided on the metal reflective layer of these optical disks.

Au exhibits high reflectance, but is expensive. A
Since g has a high reflectance and is cheaper than Au, Au is
Although it is possible to use g instead of Ag, Ag is inferior in color tone to Au compared to Au, and it is not possible to substitute Ag when the golden color is a part of the design. Therefore, there is a demand for a method of using a metal having a high reflectance other than Au for the metal reflection layer and obtaining a golden color tone.

It has been conventionally known that copper-based alloys have a color similar to golden color, but copper alloys easily form oxides and chlorides and have a problem in corrosion resistance. For example, if the copper alloy is stored at 80 ° C. and 80% RH for 1000 hours, it will not exhibit a golden color.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide at low cost an optical disk which has the appearance that many people can distinguish it as a nearly perfect golden color and the color tone is maintained for a long period of time. .

[0006]

These objects are achieved by the inventions (1) to (7) below. (1) A metal reflective layer is provided on a transparent substrate, the metal reflective layer exhibits a reflectance of 80% or more at a wavelength of 450 to 800 nm, and a color tone control layer containing a colorant is provided on the metal reflective layer. When the light transmittance T (%) of the color tone control layer at the wavelength λ (nm) is 700 ≦ λ ≦ 800, 80 ≦ T, and when 600 ≦ λ ≦ 700, 30 ≦ T ≦ 90, 450 ≦ λ ≦ An optical disk, wherein T ≦ 60 when 500. (2) The coloring agent is an azo pigment, an azo dye, aniline black, alizarin lake, alkali blue, anthranone pigment, anthranone dye, isoindoline pigment, isoindolinone pigment, carbon black, quinacridone pigment, quinophthalone pigment, quinophthalone. Dyes, dioxazine pigments, dichloroquinoxaline dyes, styryl disperse dyes, thioindigo pigments, triazine reactive dyes, nitrodiphenylamine disperse dyes, nitroso pigments, vinyl sulfone reactive dyes, pyrimidine reactive dyes, pyrocholine pigments, From phthalocyanine pigments, fluorbin pigments, bromacrylamide dyes, perinone pigments, perylene pigments, phosphonic acid reactive dyes, metal complex salt azomethine pigments, dyeing lakes, bifunctional reactive dyes and complex reactive dyes Optical disk (1) comprising at least one member-option. (3) The optical disc according to (1) or (2) above, wherein the color tone control layer has a thickness of 1 to 50 μm. (4) The optical disk according to any one of (1) to (3) above, wherein a region containing 80 to 100 atomic% of silver exists up to a depth of 40 nm or more from the surface of the metal reflective layer. (5) The optical disc according to any one of (1) to (4) above, wherein the color tone control layer is obtained by curing a coating film containing an ultraviolet curable resin. (6) The optical disc according to any one of the above (1) to (5), which has a substantially transparent intermediate protective layer between the metal reflection layer and the color tone control layer. (7) The optical disc according to any one of (1) to (6) above, which has a substantially transparent upper protective layer on the color tone control layer.

[0007]

In the optical disk of the present invention, since the color tone control layer having the above-mentioned light transmittance is provided on the metal reflection layer exhibiting the above-mentioned reflectance, when viewed from the metal reflection layer side. In addition, it has a color tone that appears to be gold to many people. Since the color tone control layer used in the present invention has good corrosion resistance, the golden color tone is maintained for a long period of time. In the present invention, since it is not necessary to use Au and the color tone control layer can be formed by a coating method, the optical disc of the present invention can be manufactured at low cost.

When Ag is used for the metal reflection layer, the metal reflection layer is apt to corrode due to the influence of the pigment or dye in the color control layer, but an intermediate protective layer which is almost transparent between the metal reflection layer and the color control layer. By providing, it is possible to suppress such corrosion.

[0009]

Specific Structure The specific structure of the invention of this application will be described in detail below.

The optical disk of the present invention has a metal reflective layer and a color tone control layer in this order on a transparent substrate. The transparent substrate is made of resin or glass, and recording light and reproducing light are emitted from the lower side of the transparent substrate. In the present invention, the structure from the bottom of the metal reflective layer to the substrate is not particularly limited, and it can be applied to various optical disks such as the read-only optical disk and the optical recording disk described above. An example of the structure of the optical disc of the present invention is shown in FIG. The optical disk shown in FIG. 1 is a write-once type having a recording layer 3 containing an organic dye, a metal reflective layer 4, a substantially transparent intermediate protective layer 5, a color tone control layer 6, and a substantially transparent upper protective layer 7 on a transparent substrate 2. It is an optical recording disk.

The metal reflective layer used in the present invention has a wavelength of 450.
It exhibits a reflectance of 80% or more in the entire range of up to 800 nm. When such a metal reflection layer is not used, a golden color does not appear even if the color tone control layer is provided.

The metal used for the metal reflection layer is not particularly limited, but for example, in the Al reflection layer used for compact discs and the like, the region where the reflectance is less than 80% exists in the wavelength range of 450 to 800 nm. , Cannot be used in the present invention. In the present invention, it is preferable to use a silver-based metal, particularly a metal or alloy mainly containing silver. The main content of silver is that the content of silver is 80 to 100 atom%, and particularly preferably 85 to 100 atom%.
It is preferable that such a region mainly composed of silver exists in a region from the surface to a depth of at least 40 nm or more. For example, when a silver film is used as the metal reflection layer, the thickness of the silver film may be usually about 40 nm to 0.5 mm.

The color tone control layer contains a colorant and has a wavelength of λ
The light transmittance T (%) in (nm) is 80 ≦ T when 700 ≦ λ ≦ 800, 30 ≦ T ≦ 90 when 600 ≦ λ ≦ 700, and T ≦ 60 when 450 ≦ λ ≦ 500. If the reflectance in each wavelength range deviates from this range, it becomes impossible to obtain a color tone close to a golden color when the color tone control layer is provided on the surface of the metal reflective layer. Less than 450 nm, more than 500 nm and less than 600 nm, and 8
It has been confirmed that there is no limit for T at λ above 00 nm. According to the present invention, as long as a color tone control layer exhibiting such a transmittance color spectrum is provided on the surface of the above-mentioned metal reflection layer, many people evaluate it as golden color. Such a fact was unexpected.

The light transmittance in each wavelength region is determined by forming a color tone control layer on the transparent substrate surface and measuring the light transmittance of this color tone control layer. At this time, the transparent substrate has a wavelength of 450
Use a material that exhibits a light transmittance of 80% or more in the entire range of up to 800 nm (for example, a glass plate or a resin plate),
The color tone control layer is formed under the same conditions as when forming on the surface of the metal reflection layer.

The wavelength of the color tone control layer is 450 to 800 nm.
It is preferable that the reflectance at 20% is 20% or less.

The colorant used in the color tone control layer is an azo pigment, an azo dye, aniline black, alizarin lake, alkali blue, anthranone pigment, anthranone dye, isoindoline pigment, isoindolinone pigment, carbon black, quinacridone pigment. , Quinophthalone pigment, quinophthalone dye, dioxazine pigment, dichlorquinoxaline dye, styryl disperse dye, thioindigo pigment, triazine reactive dye, nitrodiphenylamine disperse dye, nitroso pigment, vinyl sulfone reactive dye, pyrimidine reactive dye , Pyrocholine pigment,
At least one selected from phthalocyanine pigments, fluorobin pigments, bromacrylamide dyes, perinone pigments, perylene pigments, phosphonic acid reactive dyes, metal complex salt azomethine pigments, dyeing lakes, bifunctional reactive dyes, and complex reactive dyes. preferable. The pigments and dyes show various shades. For example, even the same azo pigment may have a yellowish tone or a reddish tone. In the present invention, in order to obtain the above-mentioned light transmittance, it may be appropriately selected from these pigments and dyes. In particular, among the above-mentioned pigments and dyes, those exhibiting a yellowish color tone are used, or In addition, it is preferable to additionally use those exhibiting a red color tone and / or those exhibiting a black or indigo color tone.

Among the above pigments and dyes, those exhibiting a yellow color tone include azo pigments, azo dyes, dyeing lakes, pyrimidine reactive dyes, nitrodiphenylamine disperse dyes, anthranone pigments, anthranone dyes. , Dioxazine pigments, fluorbin pigments, pyrocholine pigments, nitroso pigments, alizarin lakes, metal complex salt azomethine pigments, and those showing a reddish hue include azo pigments, azo dyes, quinophthalone pigments, quinophthalone dyes. , Isoindoline pigments, perylene pigments, quinacridone pigments, isoindolinone pigments, thioindigo pigments, perinone pigments, styryl disperse dyes, and those showing a black or indigo color tone include aniline black and carbon. Black, alkali blue, vinyl sulfo System reactive dye, triazine reactive dye, dichloride Lucino quinoxaline dyes, phosphonic acid reactive dyes, bromine acrylamide dyes, complex type reactive dye, difunctional reactive dyes, phthalocyanine pigments.

In this specification, a yellowish color tone is a color tone which is visually identified as bluish yellow, medium yellow or red yellow. A film containing a pigment or a dye having a yellowish color tone as a simple substance usually exhibits a reflection spectrum having a peak in the wavelength range of 550 to 600 nm. Further, the reddish color tone is a color tone which is visually identified as orange, bright red, red, crimson, and peony. A film containing a single pigment or dye showing a reddish color tone is usually 600 to 700.
The reflection spectrum which has a peak in the wavelength range of nm is shown. Further, the black or indigo color tone is a color tone which is visually identified as black, blue, ultramarine blue or green. In addition, a film that contains a pigment or a dye alone showing a black or indigo color tone as a simple substance usually has almost zero reflection in the entire visible wavelength range or a reflection spectrum having a peak in the wavelength range of 400 to 550 nm. Show.

In the present invention, as a preferable combination of the pigment and the dye, Hostaverm Yellow H3G is used.
Examples thereof include a combination of (yellow azo pigment) and chromophthal red BRN (red quinacridone pigment), and it is also preferable to add carbon black or phthalocyanine blue to this combination. A combination of a disazo pigment and an isoindolinone pigment, a carbon black added to this combination, a combination of a disazo pigment and an anthraquinone pigment, and a carbon black added to this combination are also preferable. .

The pigment used in the present invention preferably has an average particle diameter of 15 μm or less.

The thickness of the color tone control layer is not particularly limited,
Generally, it is preferable that the thickness is 1 to 50 μm. In the present invention, the light that has passed through the color tone control layer and is reflected by the surface of the metal reflection layer is made a pseudo golden color by passing through the color tone control layer again, so that even if the color tone control layer is too thin or too thick, it is transmitted. It becomes difficult to approximate light to a golden color.

The color tone control layer is formed by a coating method. Specifically, the color tone control layer is formed by applying a coating material containing the above-mentioned colorant on the surface of the metal reflective layer or the surface of the intermediate protective layer. To increase the strength of the color control layer,
It is preferable that the coating liquid contains an acrylic or epoxy type ultraviolet curable resin, and that the coating liquid is cured by ultraviolet rays or the like after coating. The solvent used for preparing the coating material is not particularly limited, but for example, ethyl acetate, MEK, xylene and the like are preferable.
If necessary, a photoreactive monomer or the like may be added to the coating liquid for adjusting the viscosity. The coating method is not particularly limited, and a method such as screen printing or spray coating may be appropriately selected according to various conditions such as the shape of the metal reflective layer and the thickness of the color tone control layer. The viscosity of the coating liquid may be appropriately determined according to the coating method and the like.

The color tone control layer may be formed directly on the surface of the metal reflection layer, but in order to prevent the metal reflection layer from deteriorating, as shown in FIG. 1, it is provided between the metal reflection layer 4 and the color tone control layer 6. It is preferable to form a substantially transparent intermediate protective layer 5. N and k at λ = 450 to 800 nm of the intermediate protective layer is n =
It is preferably 1.0 to 3.0 and k = 0.001 to 2.0, and the film thickness thereof is usually preferably 2 to 5000 nm. Further, it is preferable to provide a substantially transparent upper protective layer 7 on the color tone control layer 6 as shown in the figure. A cured film of an ultraviolet curable resin may be used for the intermediate protective layer and the upper protective layer.

[0024]

EXAMPLES The present invention will be described in more detail below by showing specific examples of the present invention.

<Example 1> A cyanine dye was applied onto a polycarbonate substrate on which continuous grooves having a pitch of 1.6 µm were transferred and dried to form a recording layer. The thickness of the recording layer is
It was set to 200 nm in the smooth region of the substrate. A 100 nm-thick Ag film is formed on this recording layer by a sputtering method,
The metal reflection layer was used. A composition containing an ultraviolet curable resin is applied on the metal reflection layer and cured by ultraviolet rays to have a thickness of 6 μm.
An intermediate protective layer of m 2 was formed. "UV" on the intermediate protective layer
A coating film containing 100 parts by weight of "OPT series transparent yellow" (manufactured by Teikoku Ink Mfg. Co., Ltd.) and 1 part by weight of carbon black was formed by silk screen printing. "UV
The "OPT series transparent yellow" is composed of 7% by weight of a disazo pigment (Disazo Yellow H10G) and 93% by weight of a UV OPT clear (containing a urethane acrylate oligomer and an acetophenone photoinitiator). Then, the coating film was cured by irradiation with 1 J / cm ² of ultraviolet rays to form a color tone control layer having a thickness of 10 μm. Further, a resin film similar to the intermediate layer was formed on the color tone control layer to form an upper protective layer, and optical disc sample No. 1 was obtained.

A sample No. 2 was prepared in the same manner as the sample No. 1 except that the intermediate protective layer was not provided.

Next, a 100 nm-thick Ag film was formed on the polycarbonate substrate on which the CD signal was transferred by a sputtering method to form a metal reflection layer. An intermediate protective layer, a color tone control layer and an upper protective layer were sequentially formed on this metal reflective layer to obtain an optical disc sample No. 3. The intermediate protective layer and the upper protective layer were the same as in Sample No. 1. The color control layer is
Colored top coat agent (SD Nippon 11 made by Dainippon Ink)
Was applied by spin coating and cured by ultraviolet rays to form a film. The thickness of the color tone control layer was 6 μm.

A sample No. 4 was prepared in the same manner as the sample No. 3 except that the intermediate protective layer was not provided.

Next, the metal reflection layer of each of the above-mentioned samples was replaced with Au.
A comparative sample was prepared as a film, and each sample and each comparative sample were alternately shown 5 times to 200 male and female subjects of various age groups. 94% of the subjects were all Au films. I decided.

The light transmittance of the color tone control layer of Sample No. 1 is shown in FIG. Regarding the light transmittance, a color tone control layer having the same thickness as that of Sample No. 1 is formed on the surface of a polycarbonate substrate having a light transmittance of 80% or more at a wavelength of 450 to 800 nm,
This was measured. As shown in FIG. 2, the transmittance T of the color tone control layer is 80 ≦ T when 700 ≦ λ ≦ 800, 30 ≦ T ≦ 90 when 600 ≦ λ ≦ 700, and T when 450 ≦ λ ≦ 500. It satisfies ≦ 60. The transmittance distribution of the color tone control layer used in Sample No. 3 also satisfied the above conditions.

In addition, a combination of (a) a disazo pigment (Sandrin Yellow H3G) and an isoindolinone pigment (Irgazin Orange BLT), (b) a disazo pigment (Disazo Yellow HR) and an isoindolinone pigment A combination of a pigment (Irgazin red 2BLT) and carbon black, (c) a combination of a disazo pigment (Disazo yellow 87) and an anthraquinone pigment (chromophthal red A3B), (d) a disazo pigment (Disazo yellow H10G) And a combination of anthraquinone-based pigment (dianthraquinonyl red) and carbon black, even when using in the color tone control layer, the same color tone as in the above-mentioned example is obtained, and the light of the color tone control layer is The transmittance was within the range of the present invention. In addition,
In these combinations, yellow-based: red-based: black or indigo-based = 7: 1: 1 (weight ratio).

In addition to the above, the combinations shown in Table 1 also gave coating films having a color tone very close to that of the Au film.

[0033]

[Table 1]

<Example 2> Sample manufactured in Example 1
CD-R recorders (RPD manufactured by Pioneer Corporation)
-1000) recorded the same CD signal as sample Nos. 3 to 4. Then, sample No. 1 to 4
The sample was stored in a thermo-hygrostat at 80% RH for 200 hours, and the block error rates (BLER) before and after storage were compared.
In addition, each sample used what did not form an upper protective layer. The results are shown below. The CD standard value of BLER is 220 count / s or less.

Sample BLER (count / s) No. After initial storage 1 0.8 1.0 2 0.8 460 3 0.3 2.5 2.5 4 0.3 300

From these results, it is understood that the reliability is remarkably improved by providing the intermediate protective layer between the metal reflection layer and the color tone control layer. From the above results, the effect of the present invention is clear.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of an optical disc of the present invention.

FIG. 2 is a graph showing a transmitted light spectrum of a color tone control layer in an example.

[Explanation of symbols]

 2 transparent substrate 3 recording layer 4 metal reflective layer 5 intermediate protective layer 6 color tone control layer 7 upper protective layer

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

Claims (7)

[Claims] 1. A metal substrate having a metal reflective layer on a transparent substrate, the metal reflective layer having a reflectance of 80% or more at a wavelength of 450 to 800 nm, and a color control layer containing a colorant on the metal reflective layer. And the light transmittance T (%) at the wavelength λ (nm) of the color tone control layer is 700 ≦ λ ≦ 800, 80 ≦ T, and 600 ≦ λ ≦ 700, 30 ≦ T ≦ 90, 450 ≦ An optical disk, wherein T ≦ 60 when λ ≦ 500. 2. The colorant is an azo pigment, azo dye, aniline black, alizarin lake, alkali blue, anthranone pigment, anthranone dye, isoindolin pigment, isoindolinone pigment, carbon black, quinacridone pigment, quinophthalone pigment. , Quinophthalone dyes, dioxazine pigments, dichlorquinoxaline dyes, styryl disperse dyes, thioindigo pigments, triazine reactive dyes, nitrodiphenylamine disperse dyes, nitroso pigments, vinyl sulfone reactive dyes, pyrimidine reactive dyes, pyrocholine dyes Pigments, phthalocyanine pigments, fluorbin pigments, bromacrylamide dyes, perinone pigments, perylene pigments, phosphonic acid reactive dyes, metal complex salt azomethine pigments, dyeing lakes, bifunctional reaction The optical disk according to claim 1, comprising at least one selected from the fees and the composite reactive dye. 3. The optical disk according to claim 1, wherein the color tone control layer has a thickness of 1 to 50 μm. 4. The optical disc according to claim 1, wherein a region containing 80 to 100 atomic% of silver exists up to a depth of 40 nm or more from the surface of the metal reflection layer. 5. The optical disc according to claim 1, wherein the color tone control layer is obtained by curing a coating film containing an ultraviolet curable resin. 6. The optical disc according to claim 1, further comprising a substantially transparent intermediate protective layer between the metal reflection layer and the color tone control layer. 7. The optical disc according to claim 1, further comprising a substantially transparent upper protective layer on the color tone control layer.