JP4075007B2 - Optical information recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording medium, and more particularly to an optical information recording medium that enables high-density optical recording using laser light having a shorter wavelength than conventional ones.
[0002]
[Prior art]
There is a demand for performing optical information recording with a higher density than conventional optical information recording media.
In order to achieve high-density optical information recording, that is, a large capacity and a high transfer rate, it is effective to reduce the spot size of laser light for recording and improve the recording linear velocity.
In order to reduce the spot size of the laser beam, specifically, the wavelength λ is set to a shorter wavelength side than the conventionally used red light side, and the laser beam is focused on the optical information recording medium. Numerical aperture of the objective lens A. There are ways to increase the size.
[0003]
In particular, the method of shortening the wavelength λ of the laser beam and the numerical aperture N.I. A. By using both of these methods and the method of increasing the spot size, the spot size can be further reduced as compared with the case where each method is applied alone.
For example, as a light source, blue-violet laser light having a wavelength near λ = 400 nm is used and a numerical aperture of N.P. A. It is theoretically possible to achieve higher density recording by using an objective lens in which = 0.85. That is, in order to increase the recording density, it is necessary to increase the value of (NA / λ).
For example, in order to obtain an optical information recording medium having a recording capacity of 8 GB, at least the numerical aperture of the objective lens is N.P. A. Is known to be 0.7 or more, and the wavelength λ of the laser light needs to be 680 nm or less.
[0004]
FIG. 10 is a schematic cross-sectional view showing an example of an optical information recording medium that has been proposed in order to realize high density information recording. The optical information recording medium 1 includes a support substrate 2, a light reflection layer, 3, an optical recording layer 4, and a light transmission layer 5 are sequentially stacked.
[0005]
The support substrate 2 is made of, for example, glass, polycarbonate resin, polyolefin resin or the like excellent in impact resistance, and has a thickness of, for example, about 1.2 mm.
[0006]
The light reflecting layer 3 is formed by depositing gold, silver, copper, aluminum, or an alloy or other metal containing these, which can totally reflect the laser light, by means of vapor deposition, sputtering, or the like. The thickness is, for example, about 50 to 100 nm.
The light reflecting layer 3 is not necessarily required if a predetermined level of reflectance can be obtained in the layer boundary with the support substrate 2 due to the characteristics of the optical recording layer 4 itself.
[0007]
The optical recording layer 4 is a layer capable of recording optical information by absorbing laser light. That is, the optical recording layer 4 is a layer made of a light-absorbing substance (light-absorbing substance) and is a layer that generates heat, melts, sublimates, deforms, or modifies when irradiated with laser light. This optical recording layer 4 is formed by uniformly coating the surface of the light reflecting layer 3 with, for example, a cyanine dye dissolved in a solvent by means such as spin coating.
Although any optical recording material can be adopted as the material used for constituting the optical recording layer 4, a light-absorbing organic dye is desirable. The thickness of the optical recording layer 4 is, for example, about 50 to 100 nm.
[0008]
The light transmission layer 5 protects the optical recording layer 4 from the outside, and irradiates laser light 7 from the surface (main surface) side through the objective lens 6 to perform optical recording and reproduction on the optical recording layer 4. This is a transparent base material that has the same impact resistance as that of the substrate 2 and is coated with, for example, an ultraviolet curable resin by a spin coating method and cured by irradiating it with ultraviolet rays. Form.
The thickness of the light transmission layer 5 is, for example, about 100 μm.
In particular, when the optical information recording medium 1 corresponding to the current red laser to blue laser is considered as the recording light, the thickness of the light transmission layer 5 is preferably 10 to 177 μm.
[0009]
The substrate 2 and the light reflecting layer 3 are in contact with each other through the first layer boundary 8.
The light reflecting layer 3 and the optical recording layer 4 are in contact with each other by the second layer boundary 9.
The optical recording layer 4 and the light transmission layer 5 are in contact with each other by the third layer boundary 10.
[0010]
In the optical information recording medium 1 having such a configuration, in order to perform optical information recording with higher density than before, the laser light 7 having a shorter wavelength and the larger numerical aperture N.D. A. When the objective lens 6 is used, the converging distance becomes shorter. Therefore, when the laser beam 7 is irradiated from the support substrate 2 side having a relatively large thickness, the optical recording layer 4 is recorded and reproduced. Since it is difficult to focus the laser spot necessary for the optical recording layer 4, the laser beam 7 is directly applied to the optical recording layer 4 from the side of the light transmitting layer 5 having a smaller thickness.
[0011]
Thus, when the optical recording layer 1 is an organic dye film when the optical information recording medium 1 is produced, the optical recording layer 4 is formed in order to stack the light transmission layer 5 thereon. It is necessary to spin coat an ultraviolet curable resin, which is a material of the light transmission layer 5, but when a liquid ultraviolet curable resin is directly laminated on the organic dye optical recording layer 4, it is in a liquid state before the curing is completed. As a result of the optical recording layer 4 being dissolved in the ultraviolet curable resin, there is a problem that the optical recording layer 4 cannot be properly formed, and an adverse effect on optical recording is considered.
[0012]
FIG. 11 is a cross-sectional view showing a spin coating process for forming the light transmission layer 5 in the optical information recording medium 1, and FIG. 12 is a cross-sectional view after the spin coating is completed. The tracking pregroove 11 and its left and right lands 12 are formed in a spiral shape in the circumferential direction.
The light reflecting layer 3 and the optical recording layer 4 are also uneven according to the shape of the pregroove 11 and the land 12, and the pits 13 can be formed on the optical recording layer 4 in the pregroove 11 or the land 12.
[0013]
As shown in FIG. 11, since the liquid ultraviolet curable resin 5A is applied to the formed optical recording layer 4, the liquid ultraviolet curable resin 5A and the optical recording layer 4 are in direct contact with each other.
Therefore, the optical recording layer 4 dissolves in the third layer boundary 10 between the optical recording layer 4 and the light transmission layer 5 and comes out of the dropping portion of the liquid ultraviolet curable resin 5A, or by its rotation in the spin coating method. Along with the liquid UV curable resin 5A shaken off in the outer peripheral direction, a phenomenon occurs that the dissolved material (organic dye) of the optical recording layer 4 flows out in the outer peripheral direction, and as shown in FIG. When the liquid ultraviolet curable resin 5 </ b> A is cured, an indefinite third layer boundary 10 </ b> A is formed between the optical recording layer 4 and the light transmission layer 5.
That is, there is a problem that the optical recording layer 4 and the light transmission layer 5 are not properly formed, and the recording and reproduction of the pits 13 by the laser light 7 are adversely affected.
[0014]
Further, as a method of forming the light transmission layer 5, in addition to the method by the spin coating method as described above, a method of bonding a sheet-like light transmission material film on the optical recording layer 4 via an adhesive layer. There is also.
FIG. 13 is a cross-sectional view showing a process of bonding a sheet-like light-transmitting material film 15 onto the optical recording layer 4 via an adhesive layer 14, and FIG. 14 is a cross-sectional view after the bonding is completed. Since the adhesive layer 14 is applied on the optical recording layer 4 that has been formed, the adhesive layer 14 and the optical recording layer 4 are in direct contact.
[0015]
Therefore, a phenomenon occurs in which the optical recording layer 4 is dissolved at the third layer boundary 16 between the optical recording layer 4 and the adhesive layer 14 and is removed from the contact portion with the adhesive layer 14, as shown in FIG. As described above, an indefinite third layer boundary 16 </ b> A is formed between the optical recording layer 4 and the light transmission layer 5. The adhesive layer 14 and the sheet-like material film 15 are in contact with each other through the fourth layer boundary 17.
That is, there is a problem that the optical recording layer 4 is not properly formed and adversely affects the recording and reproduction of the pits 13 by the laser light 7.
[0016]
[Problems to be solved by the invention]
The present invention has been considered in view of the above problems, and is an optical information recording medium having a structure in which recording light or reproduction light is irradiated from the light transmitting layer side. It is an object of the present invention to provide an optical information recording medium that can suppress dissolution of the optical recording layer due to the material of the layer.
[0017]
Another object of the present invention is to provide an optical information recording medium with high reliability by appropriately forming an optical recording layer and a light transmission layer.
[0018]
The present invention also provides an optical information recording medium capable of preventing the optical recording layer from being dissolved and obstructing the formation of the optical recording layer when the light transmission layer is formed by spin coating using an ultraviolet curable resin. This is the issue.
[0019]
Another object of the present invention is to provide an optical information recording medium capable of preventing the optical recording layer from being dissolved and obstructing the formation of the optical recording layer when the light transmissive layer is adhered by the sheet-like material film. .
[0020]
[Means for Solving the Problems]
That is, the present invention focuses on providing a protective layer capable of protecting the optical recording layer from dissolution between the optical recording layer and the light transmission layer. The support substrate and the optical recording layer formed on the support substrate And a light transmission layer formed on the optical recording layer, and reproducing or recording information on the optical recording layer by irradiating laser light from the main surface on the light transmission layer side A recording medium, wherein a protective layer made of a light-transmitting resin is provided between the optical recording layer and the light transmission layer.
[0021]
The optical recording layer can be composed of an organic dye.
[0022]
The optical recording layer can be composed of a cyanine dye or an azo dye.
[0023]
The protective layer can be composed of ultraviolet curable urethane acrylate, oligostyrene or silicon resin.
[0024]
A light reflection layer can be formed between the support substrate and the optical recording layer.
[0025]
The light transmission layer can be formed by spin coating.
[0026]
The light transmission layer can be composed of a sheet-like material film.
[0027]
An adhesive layer may be provided between the protective layer and the light transmission layer.
[0028]
The adhesive layer can be composed of an ultraviolet curable resin or an adhesive sheet.
[0029]
In the optical information recording medium according to the present invention, since the protective layer capable of protecting the optical recording layer from dissolution is provided between the optical recording layer and the light transmissive layer, depending on the material of the light transmissive layer, the light transmissive layer is formed. Prevent the optical recording layer from being dissolved by the adhesive layer material when the optical recording layer is dissolved or the light transmitting layer is formed from a sheet-like material film, and the optical recording layer and the light transmitting layer are properly formed. Can do.
Therefore, the optical recording layer and the light transmission layer can be formed as designed, and recording and reproduction by laser light irradiation from the light transmission layer side is performed with good reliability, and high-density optical information recording is realized. Can do.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Next, the optical information recording medium 20 according to the first embodiment of the present invention will be described with reference to FIGS. However, the same parts as those in FIGS. 10 to 14 are denoted by the same reference numerals, and detailed description thereof will be omitted.
1 is a cross-sectional view showing a general configuration of the optical information recording medium 20, FIG. 2 is a cross-sectional view showing a spin coating process for forming the light transmission layer 5 in the optical information recording medium 20, and FIG. 2 is a cross-sectional view of the optical information recording medium 20 in a state where spin coating has been completed. FIG.
As shown in FIG. 1, the optical information recording medium 20 includes a support substrate 2, a light reflecting layer 3, an optical recording layer 4, and a light transmitting layer 5, similarly to the optical information recording medium 1 (FIG. 10) described above. The protective layer 21 is formed between the optical recording layer 4 and the light transmission layer 5, and the pregroove 11 and the land 12 are formed on the support substrate 2 as specifically shown in FIGS. .
The optical recording layer 4 and the protective layer 21 are in contact with each other through the third layer boundary 22.
The protective layer 21 and the light transmission layer 5 are in contact with each other through the fourth layer boundary 23.
[0031]
As the liquid ultraviolet curable resin 5A for forming the light transmissive layer 5, an ultraviolet curable urethane acrylate or other arbitrary ultraviolet curable resin is adopted, and the light transmissive layer 5 is formed on the optical recording layer 4 (protective layer 21) by spin coating. Are stacked.
The optical recording layer 4 is preferably a cyanine dye, an azo dye or other organic dye.
[0032]
As a material for the protective layer 21, a material that is transparent like the light transmission layer 5, does not dissolve the optical recording layer 4, and does not dissolve in the liquid UV curable resin 5 </ b> A in the spin coating of the light transmission layer 5. For example, it is selected from ultraviolet curable urethane acrylate, oligostyrene or silicon resin.
[0033]
Further, by making the radii of the support substrate 2 and the light transmission layer 5 larger than the radii for forming the light reflection layer 3, the optical recording layer 4, and the protective layer 21, the support substrate 2 and the light transmission layer 5 are arranged on the outer periphery of each other. The adhesiveness of the support substrate 2 and the light transmission layer 5 can also be improved by allowing direct contact at the part and bonding.
[0034]
With the optical information recording medium 20 having such a configuration, the optical recording layer 4 is protected by the protective layer 21 even when the liquid ultraviolet curable resin 5A is applied to the optical recording layer 4 and spin-coated as shown in FIG. Therefore, the liquid ultraviolet curable resin 5A and the optical recording layer 4 are not in direct contact, and the organic dye of the optical recording layer 4 is not dissolved in the liquid ultraviolet curable resin 5A.
Of course, the optical recording layer 4 is not dissolved by the material of the protective layer 21.
Further, when the liquid ultraviolet curable resin 5A is cured by irradiating with ultraviolet rays, a third layer boundary 22 between the optical recording layer 4 and the protective layer 21 is clearly formed as shown in FIG. Therefore, recording and reproduction with the laser beam 7 can be performed correctly.
[0035]
Next, FIG. 4 is a sectional view showing a general configuration of the optical information recording medium 30 according to the second embodiment of the present invention, and FIG. 5 is for creating the light transmission layer 5 of the optical information recording medium 30. FIG. 6 is a cross-sectional view showing a process of bonding a sheet-like light-transmitting material film 15 onto the optical recording layer 4 via an adhesive layer 14, and FIG. 6 is a cross-section of the optical information recording medium 30 in a state where the bonding has been completed. FIG.
As shown in FIG. 4, the optical information recording medium 30 includes a support substrate 2, a light reflecting layer 3, an optical recording layer 4, and a light transmitting layer 5, similarly to the optical information recording medium 20 (FIG. 1) described above. The protective layer 21 and the adhesive layer 14 are formed between the optical recording layer 4 and the light transmission layer 5, and the light transmission layer 5 is composed of a sheet-like material film 15. As shown in FIG. 2, the pregroove 11 and the land 12 are formed on the support substrate 2.
The optical recording layer 4 and the protective layer 21 are in contact with each other through the third layer boundary 22.
The protective layer 21 and the adhesive layer 14 are in contact with each other through the fourth layer boundary 31.
The adhesive layer 14 and the sheet-like material film 15 (light transmission layer 5) are in contact with each other through the fifth layer boundary 32.
[0036]
The adhesive layer 14 needs to be transparent and capable of adhering the protective layer 21 and the light transmission layer 5. For example, an ultraviolet curable resin or an adhesive sheet can be used.
[0037]
As the sheet-like material film 15 for forming the light transmission layer 5, for example, polycarbonate resin or polyolefin resin having excellent impact resistance is adopted, and the light transmission layer is formed on the optical recording layer 4 by the adhesive layer 14. 5 are stacked.
[0038]
By using the optical information recording medium 30 having such a configuration, as shown in FIG. 5, the protective layer 21 is laminated on the optical recording layer 4, and further the adhesive layer 14 and the sheet-like material film 15 are laminated. Since the optical recording layer 4 is protected by the protective layer 21, the optical recording layer 4 and the adhesive layer 14 are not in direct contact, and by selecting the organic dye of the optical recording layer 4 and the material of the adhesive layer 14 The organic dye is not dissolved in the adhesive layer 14.
Further, if the light transmission layer 5 is formed by adhering the sheet-like material film 15 via the adhesive layer 14, a third layer between the optical recording layer 4 and the protective layer 21 is formed as shown in FIG. The layer boundary 22 can be clearly formed, and recording and reproduction by the laser beam 7 can be performed correctly.
[0039]
【Example】
Next, examples of the optical information recording medium according to the present invention will be described.
Example 1
A polycarbonate support substrate 2 having a thickness of 1.1 mm on which the continuous spiral pregroove 11 was formed was molded by an injection molding method. Gold (Au) was sputtered on the support substrate 2 to form a light reflecting layer 3 having a thickness of 100 nm.
On this light reflecting layer 3, a recording layer coating solution of an organic dye (cyanine dye) having the structure shown in FIG. 7 is spin-coated as a recording dye at a rotational speed of 2000 rpm to form an optical recording layer 4 having a thickness of 50 nm. did.
[0040]
An ultraviolet curable urethane acrylate having the structure shown in FIG. 8 was spin-coated on the optical recording layer 4 at a rotational speed of 5000 rpm and cured by irradiating with ultraviolet rays to form a protective layer 21 having a thickness of 30 nm.
An ultraviolet curable acrylate resin (SD661, manufactured by Dainippon Ink & Chemicals, Incorporated) is applied to the surface of the protective layer 21, and cured by irradiating with ultraviolet rays to form a light transmission layer 5, and an optical information recording medium 20 (FIG. 3) was created.
[0041]
With respect to the optical information recording medium 20 thus obtained, writing of the pits 13 was performed as follows.
First, the shortest pit 13 was measured using an optical disk evaluation apparatus (DDU-1000) manufactured by Pulstec Industrial Co., Ltd. equipped with a blue harmonic conversion laser head having a wavelength of 405 nm (numerical aperture NA = 0.85). Was recorded with a laser power of 10 mV. After recording, the signal was reproduced using the same evaluation apparatus with a laser output of 0.5 mV, and the reflectance, error rate, and jitter were measured. As a result, all showed good values.
[0042]
(Example 2)
In the same manner as in Example 1, a protective layer 21 was laminated, and a polycarbonate sheet material film 15 having a thickness of 100 μm was placed on the protective layer 21 with an ultraviolet curable resin (SD661, Dainippon Ink & Chemicals, Inc.). The light transmission layer 5 was prepared by pasting together with the adhesive layer 14), and the optical information recording medium 30 (FIG. 6) was evaluated in the same manner as in Example 1. The reflectance, error rate, and jitter were measured. As a result, all showed good values.
[0043]
(Example 3)
Instead of the ultraviolet curable urethane acrylate of FIG. 8 in Example 1, a protective layer 21 is formed by applying a cyclohexane solution of oligostyrene (SP-95, manufactured by Sanyo Chemical Industries, Ltd.) to produce the optical information recording medium 20. As shown in FIG. 3, when evaluation was performed in the same manner as in Example 1, the reflectance, error rate, and jitter were measured. As a result, all showed good values.
[0044]
Example 4
In place of the ultraviolet curable urethane acrylate of FIG. 8 in Example 2, a protective layer 21 is formed by applying a cyclohexane solution of oligostyrene (SP-95, manufactured by Sanyo Chemical Industries, Ltd.) to produce an optical information recording medium 30. As shown in FIG. 6, evaluation was performed in the same manner as in Example 1. As a result of measuring the reflectance, error rate, and jitter, all showed good values.
[0045]
(Example 5)
In place of the ultraviolet curable urethane acrylate of FIG. 8 in Example 1, a protective layer 21 is formed by applying an isopropyl ether solution of silicon resin (KR220, manufactured by Shin-Etsu Chemical Co., Ltd.) to produce an optical information recording medium 20 ( As shown in FIG. 3, the evaluation was performed in the same manner as in Example 1. As a result of measuring the reflectance, error rate, and jitter, all showed good values.
[0046]
(Example 6)
In place of the ultraviolet curable urethane acrylate of FIG. 8 in Example 2, an isopropyl ether solution of silicon resin (KR220, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to form a protective layer 21 to produce an optical information recording medium 30 ( As shown in FIG. 6, the evaluation was performed in the same manner as in Example 1. As a result of measuring the reflectance, error rate, and jitter, all showed good values.
[0047]
(Example 7)
The optical recording layer 4 was formed in the same manner as in Example 1 by using the azo dye in FIG. 9 instead of the recording dye (cyanine dye) in FIG. 7 in Example 1.
On the optical recording layer 4, similarly to Example 1, a protective layer 21 made of ultraviolet curable urethane acrylate having the structure shown in FIG. 8 is formed, and an ultraviolet curable acrylate resin (SD661, SD661, Dainippon Ink Chemical Co., Ltd.) was applied and cured by irradiating with ultraviolet rays to form a light transmission layer 5 to obtain an optical information recording medium 20 (FIG. 3), which was evaluated in the same manner as in Example 1. However, as a result of measuring reflectance, error rate and jitter, all showed good values.
[0048]
(Example 8)
In the same manner as in Example 7, the protective layer 21 was laminated, and a polycarbonate sheet material film 15 having a thickness of 100 μm was placed on the protective layer 21 with an ultraviolet curable resin (SD661, Dainippon Ink & Chemicals, Inc.). The light transmission layer 5 was prepared by pasting together with the adhesive layer 14), and the optical information recording medium 30 (FIG. 6) was evaluated in the same manner as in Example 1. The reflectance, error rate, and jitter were measured. As a result, all showed good values.
[0049]
Example 9
Instead of the ultraviolet curable urethane acrylate of FIG. 8 in Example 7, a cyclohexane solution of oligostyrene (SP-95, manufactured by Sanyo Chemical Industries Co., Ltd.) was applied to create the protective layer 21 to produce the optical information recording medium 20 As shown in FIG. 3, when evaluation was performed in the same manner as in Example 1, the reflectance, error rate, and jitter were measured. As a result, all showed good values.
[0050]
(Example 10)
In place of the UV curable urethane acrylate of FIG. 8 in Example 8, a cyclohexane solution of oligostyrene (SP-95, manufactured by Sanyo Chemical Industries, Ltd.) was applied to form the protective layer 21 to produce the optical information recording medium 30. As shown in FIG. 6, evaluation was performed in the same manner as in Example 1. As a result of measuring the reflectance, error rate, and jitter, all showed good values.
[0051]
(Example 11)
In place of the ultraviolet curable urethane acrylate of FIG. 8 in Example 7, a protective layer 21 is formed by applying an isopropyl ether solution of silicon resin (KR220, manufactured by Shin-Etsu Chemical Co., Ltd.) to produce an optical information recording medium 20 ( As shown in FIG. 3, the evaluation was performed in the same manner as in Example 1. As a result of measuring the reflectance, error rate, and jitter, all showed good values.
[0052]
(Example 12)
In place of the ultraviolet curable urethane acrylate of FIG. 8 in Example 8, an isopropyl ether solution of silicon resin (KR220, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to create a protective layer 21 to produce an optical information recording medium 30 ( As shown in FIG. 6, the evaluation was performed in the same manner as in Example 1. As a result of measuring the reflectance, error rate, and jitter, all showed good values.
[0053]
(Comparative Example 1)
The UV curable resin (SD661, manufactured by Dainippon Ink & Chemicals, Inc.) was applied to the light without applying the UV curable urethane acrylate of FIG. 8 in Example 1, that is, without forming the protective layer 21. When an attempt was made to form the transmissive layer 5, the optical recording layer 4 was missing at the resin dripping site, and discoloration due to the dissolution of the optical recording layer 4 was observed on the entire surface of the disk at the end of spin coating.
[0054]
(Comparative Example 2)
8 without applying the ultraviolet curable urethane acrylate of FIG. 8 in Example 1, that is, without forming the protective layer 21, an ultraviolet curable resin (DV003, manufactured by Nippon Kayaku Co., Ltd.) is applied to form a light transmission layer. As a result, when the optical recording layer 4 was dissolved, a loss due to dissolution of the optical recording layer 4 was observed, and discoloration due to dissolution of the optical recording layer 4 was observed on the entire surface of the disk at the end of spin coating.
[0055]
【The invention's effect】
As described above, according to the present invention, since the protective layer is provided between the optical recording layer and the light transmission layer, dissolution by the material of the light transmission layer of the optical recording layer or its adhesive layer is avoided, and good characteristics are obtained. The optical information recording medium can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a general configuration of an optical information recording medium 20 according to a first embodiment of the present invention.
2 is a cross-sectional view showing a spin coating process for forming a light transmission layer 5 in the optical information recording medium 20. FIG.
FIG. 3 is a cross-sectional view of the optical information recording medium 20 in a state where spin coating has been completed.
FIG. 4 is a sectional view showing a general configuration of an optical information recording medium 30 according to a second embodiment of the present invention.
5 shows a step of bonding a sheet-like light transmissive material film 15 on the optical recording layer 4 via an adhesive layer 14 in order to form the light transmissive layer 5 of the optical information recording medium 30. FIG. It is sectional drawing.
FIG. 6 is a cross-sectional view of the optical information recording medium 30 in a state where pasting is completed.
7 is a structural formula of an organic dye (cyanine dye) used as a recording dye of the optical recording layer 4 in Examples 1 to 6 of the present invention and Comparative Examples 1 and 2. FIG.
FIG. 8 is a structural formula of an ultraviolet curable urethane acrylate used as an ultraviolet curable resin of the light transmission layer 5 in Examples 1, 3, 5, 7, 9, and 11 of the present invention.
FIG. 9 is a structural formula of an organic dye (azo dye) used as a recording dye of the optical recording layer 4 in Examples 7 to 12 of the present invention.
FIG. 10 is a schematic cross-sectional view showing an example of an optical information recording medium that has been proposed in order to realize high density information recording.
11 is a cross-sectional view showing a spin coating process for forming the light transmission layer 5 in the optical information recording medium 1. FIG.
FIG. 12 is a cross-sectional view showing a state where spin coating is completed.
13 is a cross-sectional view showing a process of bonding a sheet-like light-transmitting material film 15 on the optical recording layer 4 via an adhesive layer 14. FIG.
FIG. 14 is a cross-sectional view showing a state where bonding is completed.
[Explanation of symbols]
1 Optical information recording medium (Fig. 10)
2 Support substrate 3 Light reflection layer 4 Optical recording layer 5 Light transmission layer 5A Liquid ultraviolet curable resin for forming the light transmission layer 5 (FIG. 11)
6 Objective lens 7 Laser light (recording light, reproduction light)
8 First layer boundary 9 between the substrate 2 and the light reflecting layer 3 Second layer boundary 10 between the light reflecting layer 3 and the optical recording layer 4 Between the optical recording layer 4 and the light transmitting layer 5 Third layer boundary 10A An indefinite third layer boundary between the optical recording layer 4 and the light transmission layer 5 (FIG. 12)
11 Pre-groove 12 Land 13 Pit 14 Adhesive layer 15 Sheet-like material film 16 Third layer boundary between the optical recording layer 4 and the adhesive layer 14 (FIG. 13)
16A Indiscriminate third layer boundary between the third layer boundaries 16 (FIG. 14)
17 Fourth layer boundary between the adhesive layer 14 and the sheet-like material film 15 (FIG. 14)
20 Optical information recording medium (first embodiment, FIGS. 1 and 3)
21 Protective layer 22 Third layer boundary 23 between optical recording layer 4 and protective layer 21 Fourth layer boundary 30 between protective layer 21 and light transmission layer 5 Optical information recording medium (second embodiment) Form, FIG. 4, FIG. 6)
31 Fourth layer boundary 32 between the protective layer 21 and the adhesive layer 14 Fifth layer boundary between the adhesive layer 14 and the sheet-like material film 15 (light transmission layer 5)

Claims (7)

A support substrate;
An optical recording layer formed on the support substrate;
A light transmission layer formed on the optical recording layer,
An optical information recording medium for reproducing or recording information on the optical recording layer by irradiating laser light from the main surface on the light transmitting layer side,
Between the light-transmitting layer and the optical recording layer, Rutotomoni a protective layer made of a light transmissive resin,
This protective layer is composed of UV curable urethane acrylate, oligostyrene or silicon resin, and
The optical information recording medium , wherein the optical recording layer is composed of an organic dye .     2. The optical information recording medium according to claim 1, wherein the optical recording layer is composed of a cyanine dye or an azo dye.     The optical information recording medium according to claim 1, wherein a light reflection layer is formed between the support substrate and the optical recording layer.     2. The optical information recording medium according to claim 1, wherein the light transmission layer can be formed by a spin coating method.     2. The optical information recording medium according to claim 1, wherein the light transmission layer is made of a sheet-like material film. 6. The optical information recording medium according to claim 5 , wherein an adhesive layer is provided between the protective layer and the light transmission layer. 7. The optical information recording medium according to claim 6 , wherein the adhesive layer is made of an ultraviolet curable resin or an adhesive sheet.

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