JP2003178489A - Information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium in which a light transmitting substrate is used as a first disk in a single body or a part of a layered structure, a light reflecting layer, a transmitting layer, an organic dye recording layer and a dye protective layer are deposited on a light transmitting substrate as a second disk, and the light reflecting layer of the first disk is laminated with an adhesive layer on the dye protective layer of the second disk and in which favorable recording can be performed in the second disk by allowing laser light to enter the light transmitting substrate side of the first disk. <P>SOLUTION: In the optical recording medium composed of the first disk 1 and the second disk 2 as shown in Fig. 1, an organic dye recording layer 22, a light reflecting layer 32 and a dye protective layer 42 are deposited on a light transmitting substrate 12 to constitute the second disk and the second disk is laminated on the first disk with an adhesive layer 52. Further, a light transmitting layer 62 is formed between the light reflecting layer 32 and the organic dye recording layer 22. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium having a recording layer and a reflecting layer on a transparent transparent substrate.

[0002]

2. Description of the Related Art An organic dye recording layer that absorbs laser light directly or through another layer on a transparent transparent substrate,
A write-once optical disc, which is an optical recording medium having a metal reflection layer directly or on another recording layer, is widely known. DVD as one of the write-once optical discs
-There is R. The DVD-R has a thickness of 0.6 mm and a single side of 4.7.
A disc with a GB recording capacity and a thickness of 0.6 m
Single-sided recording DVD-R with a capacity of 4.7 GB in the form of bonding two unwritable dummy disks.
There are two types, a double-sided recording type DVD-R having a capacity of 9.4 GB in which two discs each having a recording capacity of 4.7 GB on one side are bonded and recording and reproducing are performed by using a laser from both sides.

The double-sided recording type DVD-R which records and reproduces data from both sides using a laser has a large capacity of 9.4 GB, but in the recording and reproducing apparatus, recording and reproducing lasers are installed above and below the surface of the disk. I have to do it. Therefore, the recording / reproducing apparatus becomes expensive, and a commonly used DVD-R is a single-sided recording type DVD-R.
R is often used. This DVD-
R has an authoring standard and a general standard, but there is no difference in terms of capacity.

In an optical recording medium having an organic dye recording layer, pits are formed by a laser irradiated at the time of recording at a temperature at which the applied dye can be decomposed, and recording is performed. Optical recording media having a single-sided, single-layer recording type organic dye recording layer often have the organic dye recording layer directly provided on a transparent substrate. At this time, when pits are formed by the laser irradiated during recording, the amount of heat generated when the dye is decomposed also overlaps, and the substrate is deformed during pit formation. The polycarbonate used for the most transparent substrate has a heat distortion temperature of 145 to 150 ° C., and the heat generated during the decomposition of the dye causes the deformation of the substrate. In the optical disc using the organic dye recording layer, the dye is thermally decomposed during recording, and the substrate is deformed by the generated heat. That is, the substrate deformation is formed at the same position as the pit formed in the organic dye recording layer, and the substrate deformation plays a large role in the formation of the pit.

Considering the structure of a disc having a structure in which two single-sided recording discs are bonded together, when recording is performed on the two discs by using a laser only from one side of the disc, There is a large difference in the substrate deformation method between the first disk near the laser incident side and the second disk far from the incident light. The first disk has a transparent substrate coated with a dye, and a reflective film formed thereon. On the other hand, the second disk has a structure in which a reflective film is formed on a transparent substrate and a dye is applied on the reflective film. The deformation of the substrate during recording is largely due to the decomposition heat of the dye, but the second disk has a structure in which the reflection film radiates the decomposition heat, and the rigidity of the reflection film also adds to the deformation of the substrate. It has a difficult structure. This problem exists regardless of the presence or absence of the recording layer of the first disc, and when aiming for higher density in the future,
This is a problem that can occur even in a film incident type disk having the same structure as the second disk.

Therefore, if a layer similar to the substrate deformation is provided between the reflective film of the second disk and the organic dye recording layer, these problems can be solved. The condition of the layer provided at this time is that the deformation of the substrate is similar to that of polycarbonate and that the light transmittance is good. Examples of the resin that satisfies this condition include polycarbonate used for transparent substrates. The heat distortion temperature of polycarbonate is 145 to 150 ° C., and the light transmittance is 87 to 89%. Moreover, polymethacrylate is mentioned as a resin similar to this. Polymethacrylate has a heat distortion temperature of 100 to
The temperature is 110 ° C., and the light transmittance is 92 to 93%. In this case, we decided to focus on these two materials.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to use a light-transmissive substrate as a first disk or as a part of a layer structure, and as a second disk a light-reflective layer on a light-transmissive substrate. , A light transmitting layer, an organic dye recording layer, a dye protective layer are laminated, and a light reflecting layer of the first disc and a dye protective layer of the second disc are bonded together by an adhesive layer,
(EN) Provided is an optical recording medium capable of performing favorable recording on a second disk by injecting a laser from the side of a light transmissive substrate of the first disk.

[0008]

[Means for Solving the Problems] As shown in FIG.
In an optical recording medium composed of a first disc 1 and a second disc 2, a light transmissive substrate 12 is used as a second disc.
In the optical recording medium having a structure in which the organic dye recording layer 22, the light reflection layer 32, and the dye protection layer 42 are formed on the above, and the first disk and the second disk are bonded together with the adhesive layer 52, the following method is used. use. A light transmission layer 62 is formed between the light reflection layer 32 and the organic dye recording layer 22.

By the above-mentioned method, it is possible to provide an excellent optical recording medium which can satisfactorily perform good recording on the second disk.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiments of the present invention will be described below, but the present invention is not limited thereto. First,
As the first step, the method for producing the first disc will be described below. The light transmissive substrate includes a transparent material, a resin typified by a polycarbonate resin, an acrylic resin, an epoxy resin, an ABS resin, glass, or the like. As a resin that can be easily handled, a transparent resin material such as a polycarbonate resin or a polymethylmethacrylate resin can be used. The transparent substrate can be manufactured by injection molding these transparent resin materials, but the manufacturing method is not limited to this.
It may be manufactured by the 2P (Photo-Polymer) method.

At least one surface of the light transmissive substrate has a pregroove for tracking of 0.3 μm to
The grooves may be formed concentrically or spirally at intervals of 1.6 μm, and the groove depth of the pregroove is 100 nm in order to obtain an amplified reproduction signal by utilizing the interference effect of light. It is desirable that the thickness be 250 nm. Pre-pits on which information is recorded or predetermined patterns such as grooves for tracking or addressing are provided on the surface of the light transmissive substrate as required.

Next, an organic dye recording layer is provided directly on the above-mentioned light transmissive substrate or via another inorganic or organic layer. The recording layer can be formed by a spin coating method or a vapor deposition method, and a spin coating method using a solvent is particularly preferable. As the solvent used during the film formation, for example, ethyl cellosolve, methyl cellosolve, methanol, tetrafluoropropanol and the like can be used.

The thickness of the recording layer to be formed is 20 nm to 20
0 nm is preferred. As the dye of the dye thin film forming the organic dye recording layer, one having the property of causing chemical changes such as decomposition, sublimation, melting, and vaporization upon irradiation with a recording laser is used. Organic dyes that meet these conditions include cyanine dyes, squarylium dyes, croconium dyes, azurenium dyes, triarylamine dyes, anthraquinone dyes, metal-containing azo dyes, dithiol metal complex salt dyes, indoaniline metal. Complex dye,
Examples include phthalocyanine dyes, naphthalocyanine dyes, intermolecular CT complex dyes, and porphyrin dyes. In the organic dye recording layer of the present invention, these dyes may be used alone or in combination.

In addition to the recording dye, the organic dye recording layer contains an antioxidant, a quencher such as a dithiol complex, and the like.
Nitrocellulose, cellulose acetate, ketone resin, acrylic resin, polyvinyl butyral, polycarbonate,
You may add binders, such as polyolefin.

Next, a light-reflecting layer is formed on the above-mentioned organic dye recording layer by Ag, Al, Au, Cu, Cr, Ni, Pt, Pd.
, Etc. are not particularly limited. The light reflection layer 3 is
The film can be formed by vacuum vapor deposition, sputtering, ion plating or the like. The film thickness of the reflective layer to be formed is preferably 0.01 μm to 0.2 μm.

As a second step, a method for making a second disc will be described below. A light-reflecting layer is formed on the light-transmitting substrate similar to the light-transmitting substrate of the first disc in the same manner as the light-reflecting layer of the first disc. The film thickness of the reflective layer to be formed is
It is preferably 0.1 μm to 0.2 μm. Then, as a light transmitting layer on the light reflecting layer, polymethacrylate or
The polycarbonate is applied using a spin coating method or the like. As the solvent used, tetrahydrofuran, methylene chloride, N, N'-dimethylformamide, chloroform, pyridine, dioxane, thiophene metacresol, or the like can be used. The light transmission layer to be formed is 2
0 nm to 100 nm is preferable.

However, since a solvent is used when applying the light transmitting layer, the light reflecting layer must be formed densely. If the light-reflecting layer is not densely formed, the solvent used for forming the light-transmitting layer enters the gap of the light-reflecting layer through the gap and reaches the light-transmitting substrate, and dissolves the substrate. . Dissolution of the light-transmissive substrate leads to an increase in errors and jitter during recording / reproduction and must be avoided. Examples of (Chemical formula 1) and (Chemical formula 2) used for the light transmitting layer used at this time are shown in Tables 1 and 2, but the present invention is not limited thereto.

[0018]

[Table 1]

[0019]

[Table 2]

An organic dye recording layer is coated on this light transmitting layer in the same manner as the organic dye recording layer of the first disk. A dye protective layer is formed on the organic dye recording layer. The dye protective layer may be an inorganic compound or an organic compound, but is not particularly limited. Examples of inorganic compounds include rare earths containing Yu, A
u, Ag, Al, As, Ba, Be, Bi, Ca, Co, Cu, Fe, Ga, G
e, Hf, In, Mg, Ni, Pb, Pd, Rh, Sc, Si, Sn, Ta, T
Metals such as i, V, W, Zn, and Zr, and their oxides, sulfides, nitrides, halides, fluorides, carbonates, sulfates,
Examples thereof include nitrates and nitrites. Examples of organic compounds include resins such as vinyl acetate resins and vinyl chloride resins, resins such as polydimethylsiloxane, and organic substances such as sucrose, tartaric acid, and paraffin. When used as a separate layer, these may be used alone, or may be mixed and laminated. The film thickness of the dye protective layer to be formed is preferably 0.005 μm to 0.04 μm.

Finally, as a third step, the light reflection layer of the first disk and the dye protection layer of the second disk are attached. As the adhesive layer, an organic material such as an ultraviolet curable acrylic resin, an ultraviolet curable resin of an ultraviolet curable epoxy resin, an ultraviolet curable adhesive, an epoxy adhesive, a silicone resin, a silicone adhesive, or a hot melt adhesive is used. be able to. The thickness of the protective layer is 0.1 μm to 100 μm
m is preferred. The adhesive layer can be formed by a usual method such as spin coating, gravure coating, spray coating, or roll coating.

According to the above method, an organic dye recording layer and a light reflecting layer are laminated on a light transmitting substrate as a first disc,
As a second disc, a light reflective layer, a light transmissive layer, an organic dye recording layer, and a dye protective layer are laminated on a light transmissive substrate, and the light reflective layer of the first disc and the dye protective layer of the second disc are stacked. In the recording medium bonded with the adhesive layer, it is possible to provide an optical recording medium in which a laser is incident from the light transmissive substrate side of the first disc and good recording can be performed on the second disc.

Further, as the first disc, a 0.6 mm light transmissive substrate having no recording layer and no reflective layer and not formed with a tracking pre-groove is used.
An optical recording medium in which a second disc was prepared was also prepared in the same manner as described above. Also in such an optical recording medium, it is possible to provide an optical recording medium capable of performing favorable recording on the second disc by injecting a laser from the light-transmissive substrate side of the first disc.

[0024]

EXAMPLES In order to specifically show the effects of the present invention,
A specific description will be given with reference to the drawings. Although the present invention will be specifically described with reference to examples, the embodiments of the present invention are not limited thereto.

Example 1 FIG. 1 shows an example of the structure of an optical recording medium according to the present invention. First, the manufacturing method of the first disk will be described below. A polycarbonate resin is injection-molded using an injection molding machine equipped with a stamper on which a pre-format pattern is formed to obtain a diameter of 120.
mm, and a plate thickness of 0.6 mm was produced.
On the obtained light transmissive substrate 1, tracking pregrooves were concentrically formed with a track pitch of 0.8 μm and a groove width of 0.3 μm. A solution having a concentration of 1% by weight of an azo dye represented by the structural formula shown in (Chemical Formula 3) below was prepared as a recording layer on the light-transmissive substrate on which the pregroove was formed, and was subjected to a spin coating method. Coating was performed at a film thickness of 200 nm to form an organic dye recording layer.

[0026]

[Chemical 3]

When the dye was applied, tetrafluoropropanol was used as a solvent to make an azo dye solvent, which was filtered through a filter to remove insoluble materials. The light-transmitting substrate coated with this organic dye is 70
It was dried at ℃ for 1 hour. As a light reflecting layer on the organic dye recording layer, Au was sputtered to a film thickness of 0.020 μm.
The film was formed at m.

Next, a method for producing the second disc will be described below. A light transmissive substrate having pregrooves was prepared in the same manner as the light transmissive substrate of the first disk. As a light-reflecting layer on the light-transmissive substrate on which this pre-groove is formed,
Au was formed into a film with a thickness of 0.1 μm by sputtering, similarly to the light reflecting layer of the first disk. On this light reflection layer, as a light transmission layer, polymethacrylate (Chemical formula 1) shown in Table 1 is used.
Dissolved in tetrahydrofuran, polymethacrylate
(Chemical Formula 1) A solution having a concentration of 1% by weight was prepared and applied to have a film thickness of 80 nm by a spin coating method to form a light transmitting layer. An organic dye recording layer was coated on this light transmitting layer in the same manner as the organic dye recording layer of Disc 1. However, as a pigment,
Was used.

(Example 2) to (Example 5) are the polymethacrylates (Chemical formula 1) of Table 1 in the light transmitting layer of the second disk.
Samples were prepared in the same manner as in (Example 1), except that (Chemical Formula 1) was used. Next, instead of the polymethacrylate of Table 1, polycaphobonate (Chemical Formula 2) of Table 2 was used to form a disc in the light transmitting layer of the second disc, and the results were obtained from (Example 6) to (Example 6). Example 13). At this time,
Polycarbonate was dissolved in ethylene chloride to prepare a solution having a concentration of 1% by weight of polycarbonate, and the solution was applied by spin coating. Further, a first disc was prepared by using a 0.6 mm light transmissive substrate having no recording layer and no reflective layer and on which a tracking pre-groove was not formed, and a second disc was prepared (Example 2). To an optical recording medium manufactured as in (Example 13) (Example 1).
4) to (Example 26).

(Comparative Example 1) and (Comparative Example 2) are disks in which the light transmitting layer of the second disk is not formed in (Example 1) and (Example 13), and (Comparative Example 3) and (Comparative Example 4) includes (Example 14) and (Example 26).
In the above, the disc in which the light transmission layer of the second disc is not formed. Data was recorded / reproduced on / from the optical disks of the samples of (Example 1) to (Example 26) and (Comparative Example 1) to (Comparative Example 4) using an optical disk evaluation device DDU1000 manufactured by Pulstec Industrial Co., Ltd. Optical recording medium radius 40m
At m, a laser beam having a wavelength of 650 nm was irradiated as a recording laser beam with a power having an optimum jitter value to record image data information. After that, wavelength 650nm
The recorded laser beam was irradiated with laser power of 0.5 mW to reproduce the recorded image data information, and the jitter value was measured. The results are shown in Table 3.

[0031]

[Table 3]

In the samples of the present invention in which the light transmitting layer was formed on the second disk as in (Example 1) to (Example 26), the jitter was 8% or less in the second disk, which was excellent. I was able to record and play. On the other hand, as in (Comparative Example 1) to (Comparative Example 4), good recording / reproducing could not be performed in the samples in which the light transmitting layer was not formed on the second disk. From the above results, the present invention can provide an optical recording medium that performs good recording when good recording is performed on the second disc from the light transmissive substrate side of the first disc. It became clear that it is possible.

[0033]

According to the above-mentioned inventions of claims 1 to 5, the light-transmissive substrate is used as the first disk alone or as a part of the layer structure, and the light-transmissive substrate is used as the second disk. Light reflection layer, light transmission layer, organic dye recording layer on the substrate,
In a recording medium in which a dye protection layer is laminated and the light reflection layer of the first disc and the dye protection layer of the second disc are bonded together with an adhesive layer, a laser is incident from the light transmissive substrate side of the first disc. Then, there is an effect that good recording can be performed on the second disk.

[Brief description of drawings]

FIG. 1 is a sectional view of an information recording medium according to the present invention.

[Explanation of symbols]

1 first disc 2 second disk 12 Light-transmissive substrate (second disk) 22 recording layer (second disc) 32 reflective layer (second disc) 42 Dye protection layer (second disc) 52 Adhesive layer 62 Light transmission layer (second disc)

Claims (5)

[Claims] 1. A light-transmissive substrate is used alone or as part of a layer structure as a first disc, and a light-reflecting layer, an organic dye recording layer, and a dye protective layer are provided on a light-transmissive substrate as a second disc. In a recording medium in which the dye protective layers of the first disc and the second disc are laminated and adhered by an adhesive layer, light transmission is performed between the organic dye recording layer of the second disc and the light reflecting layer. An optical recording medium forming a layer. 2. A first disc having an organic dye recording layer and a light reflecting layer laminated on a light transmissive substrate, and a second disc having a light reflecting layer, an organic dye recording layer and a dye protection on the light transmissive substrate. Between the organic dye recording layer of the second disc and the light reflection layer in a recording medium in which the layers are laminated and the light reflection layer of the first disc and the dye protection layer of the second disc are bonded by an adhesive layer. An optical recording medium on which a light transmitting layer is formed. 3. A light transmissive substrate is used as the first disc, and a light reflective layer is provided on the light transmissive substrate as the second disc.
In a recording medium in which an organic dye recording layer and a dye protective layer are laminated, and the dye protective layers of the first disc and the second disc are bonded by an adhesive layer, the organic dye recording layer of the second disc and the light reflection An optical recording medium in which a light transmitting layer is formed between the layers. 4. An optical recording medium according to claim 1, claim 2 or claim 3, wherein the polymethacrylate represented by the formula (1) is used in the light transmitting layer. [Chemical 1] [In (Formula 1), n represents an integer. R ₁ is CH ₃ , C
Represents ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉ , and C ₅ H ₁₁ . ] 5. An optical recording medium according to claim 5, claim 6 or claim 7, wherein the polycarbonate represented by the chemical formula (2) is used for the light transmitting layer. [Chemical 2] [In (Formula 2), n represents an integer. R ₂ represents a compound containing a benzene ring. ]