JPH09306042A - Production of optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of unequal curing in a photo-curing treatment of the photo-curing adhesive interposed between substrates and to avert the damage and deformation of the substrates by light irradiation. SOLUTION: In this process, the production of an optical recording medium formed by disposing two sheets of the substrates for the optical recording medium, at least one of which have information recording layers, in such a manner that the main surface sides having these information recording layers face each other, is carried out. In such a case, the two substrates for the optical recording medium are aligned by interposing the photo-curing adhesive between the substrates stuck to each other and the photo-curing treatment of the photo- curing adhesive is carried out by executing the light irradiation from both outer sides of the two substrates for the optical recording medium.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a method for manufacturing an optical recording medium.

[0002]

2. Description of the Related Art As an optical recording medium for recording various information for audio, video, and the like, a ROM (Read) such as an optical disk, an optical card, a magneto-optical disk, and a phase change optical recording medium for recording or reproducing by light irradiation.
There are optical recording media such as only memory (write only) type, write-once type, and rewritable type. For example, in a ROM type such as a compact disk, phase pits, pre-grooves for recording data information, tracking servo signals, etc. are recorded on the information recording layer. Fine irregularities such as pre-grooves are also formed in magneto-optical media such as write-once type, rewritable type or phase change, etc.

The information recording layer having fine irregularities can be formed by an injection molding method or a 2P (photopolymerization) method.

In the optical recording medium, as shown in the schematic sectional view of FIG. 1, a first substrate 1 and a second substrate 2 are provided.
On which the first and second information recording layers 11 and 12 are formed, and the transparent intermediate film 33 is interposed between the first and second information recording layers 11 and 12, so that the first and second information recording layers 11 and 12 are formed on both substrates 1 and 2. There has been proposed a structure in which the two are aligned so as to be inside each other.

In this optical recording medium, a data recording pit, or a data recording pit, is formed on one main surface of the first substrate 1 simultaneously with the molding of the first substrate 1 by injection molding of a light transmissive resin such as polycarbonate. A first fine concavo-convex portion 21 such as a pre-groove is formed, and a semitransparent film 13 made of, for example, a sputtered film of SiN is formed on the first fine concavo-convex portion 21 to form the first information recording layer 11.

On the other hand, by the same method as that for the first substrate 1, the second substrate 2 on which the second fine irregularities 22 such as data recording pits or pre-grooves on one main surface are formed by injection molding. Formed, and Al is formed on the second fine irregularities 22.
A second information recording layer 12 is formed by depositing a reflective film 14 such as a vapor deposition film.

Then, as shown in FIG. 2, the second substrate 2 is mounted on the horizontal base 52 of the rotary chuck 50, and the center hole 2 thereof is formed.
The central axis 51 of the rotary chuck is passed through h, and the second information recording layer 12 is placed and held so that the second information recording layer 12 faces upward.
The photo-curable adhesive 3 is applied on the information recording layer 12 of FIG. Next, the first substrate 1 is placed in the center hole 1h thereof so as to penetrate the center axis 51 of the rotary chuck, and the first information recording layer 1 is placed.
1 and the second information recording layer 12 are aligned so that they are on the inner side.

Next, as shown in FIG. 3, the rotary chuck 5
By rotating 0 at a high speed, the photocurable adhesive 3 interposed between the first and second substrates 1 and 2 is uniformly stretched.

Then, as shown in FIG. 4, the first substrate 1
From the side, light irradiation, for example UV irradiation, for example, 2 J / c
m ² integrated light amount to cure the photocurable adhesive 3,
While adhering the first substrate 1 and the second substrate 2 to each other, the transparent intermediate film 33 is formed by the photocurable adhesive 3.
An optical recording medium having a structure in which the first substrate 1 and the second substrate 2 are bonded together is formed.

Information is read from the first information recording layer 11 and the second information recording layer 12 with respect to this optical recording medium, as shown in FIG. 1, for example, from the substrate 1 side by a solid line and a chain line. It is performed by irradiating light L.

[0011]

However, in the prior art, light irradiation for curing the photocurable adhesive 3 interposed between the first and second substrates 1 and 2 as described above, for example, ultraviolet rays. Irradiate 1 from the first substrate 1 side.
Since it was performed only once, for example, ultraviolet rays were emitted from the first substrate 1
The amount of ultraviolet light that is absorbed by itself and reflected by the semitransparent film 13 and absorbed by the reflective film 14 actually contributes to the photocuring treatment of the photocurable adhesive 3 is considerably reduced. It was

Further, since the photo-curable adhesive 3 itself also absorbs ultraviolet rays, the amount of ultraviolet rays is further increased at a position distant from the ultraviolet irradiation surface side of the first substrate 1, that is, at a deeper position. As a result, there is unevenness in the progress of the photocuring reaction in the depth direction of the photocurable adhesive 3,
Especially in the deep portion, the curing of the photo-curable adhesive 3 is likely to be insufficient, and therefore, the first substrate 1 and the second substrate 2 have had poor adhesion.

The thickness of the transparent intermediate film 33, that is, the photocurable adhesive 3 varies depending on the type of information read from the optical recording medium, but is within a certain limited range of about 1 to 100 μm. In particular, in the case where the transparent intermediate film 33 is of a thick type such as several tens of μm,
At a position farther from the ultraviolet irradiation surface side, that is, at a deeper position, the amount of ultraviolet light further decreases.

For example, in the so-called single-sided read type two-layer optical recording medium of FIG. 1 described above, a semitransparent film is formed on one substrate, and the thickness of the transparent intermediate film 33 is 40.
Since it is required to be at least μm, when UV irradiation is performed from the first substrate 1 side, a photocurable adhesive is provided at a position away from the UV irradiation surface side, for example, near the interface of the reflective film 14 of the second substrate 2. The agent 3 tends to be insufficiently cured.

In order to prevent unevenness in the progress of the photo-curing reaction of the photo-curing adhesive 3 in the depth direction,
When a larger amount of ultraviolet rays are irradiated, the amount of ultraviolet rays absorbed by the substrate also increases, which causes damage to the substrate and causes abnormal deformation such as skewing, which causes recording and reproduction errors.

Therefore, the present invention prevents the occurrence of uneven curing in the photo-curing treatment of the photo-curable adhesive 3 interposed between the first substrate 1 and the second substrate 2 and also during photo-curing. In order to obtain an optically excellent optical recording medium, it is possible to surely cure the photo-curable adhesive 3 without increasing the amount of light irradiation, thereby avoiding damage and deformation of the substrate due to this light irradiation. To do.

[0017]

The present invention provides two optical recording medium substrates, at least one of which has an information recording layer.
In the case of manufacturing an optical recording medium in which the main surfaces having the respective information recording layers are opposed to each other, the two optical recording medium substrates are provided, and a photocurable adhesive is interposed between the bonding surfaces. Then, the photocurable adhesive is subjected to photocuring treatment by irradiation with light from both outer sides of the two optical recording medium substrates.

According to the present invention, the two optical recording medium substrates are aligned on the main surface side having the respective information recording layers with the photocurable adhesive interposed, and the photocurable adhesive is photocured. To
By performing light irradiation from both outer sides of the two substrates for an optical recording medium, the photocurable adhesive is sufficiently cured even at a position distant from the ultraviolet irradiation surface side, that is, at a deeper position. Could be done without causing.

Further, since the amount of ultraviolet rays applied to the substrate itself can be reduced, it is possible to avoid abnormal deformation of the substrate without damaging the substrate.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. Hereinafter, the case of applying to a disc-shaped, so-called disc-shaped optical disc will be described, but the present invention is not limited to such an optical disc and the shape, and a magneto-optical disc, a phase change disc,
In addition, the present invention can be applied to various optical recording media having fine irregularities such as a card shape and a sheet shape in the information recording layer.

In this example, as shown in the schematic sectional view of FIG. 1, the first substrate 1 and the second substrate 2 on which the first and second information recording layers 11 and 12 are formed are transparent intermediate layers. This is a case where an optical recording medium having a matched structure is obtained through the film 33.

In this case, data recording is performed on one main surface of the first substrate 1 simultaneously with the molding of the first substrate 1 by injection molding of a light-transmissive resin such as polycarbonate, as described with reference to FIG. First fine irregularities 21 such as pits or pregrooves are formed, and a semitransparent film 13 made of, for example, a sputtered film of SiN is formed on the first fine irregularities 21 to form the first information recording layer 11.

On the other hand, by the same method as the first substrate 1, the second substrate 2 having the second fine irregularities 22 such as data recording pits or pregrooves on one main surface is formed by injection molding. Formed, and Al is formed on the second fine irregularities 22.
A second information recording layer 12 is formed by depositing a reflective film 14 such as a vapor deposition film. This reflective film 14 is actually several tens of nanometers.
Since the reflective film 14 is formed to have a thickness of about m,
Has an ultraviolet transmittance of about 10%.

Then, as shown in FIG. 2, the second substrate 2 is placed in the center hole 2h thereof on the horizontal base 52 of the rotary chuck 50 by the disk-shaped vacuum chuck of the spin coater.
The central axis 51 of the rotary chuck is penetrated, the second information recording layer 12 is placed so as to face upward, and the second chuck is held by the rotary chuck. For example, a liquid photo-curable adhesive is applied on the second information recording layer 12. The agent 3 is placed, for example, by dropping. Then the first
The center hole 1h of the substrate 1 is penetrated through the center axis 51 of the rotary chuck, and the first information recording layer 11 and the second information recording layer 12 are aligned so as to be inside.

Next, as shown in FIG. 3, the rotary chuck 5
By rotating 0 at a high speed of 1000 to 4000 times per minute, for example, the photo-curable adhesive 3 interposed between the first and second substrates is stretched to have a uniform thickness.

Thereafter, the first and second substrates 1 and 2 are
In the state where the photo-curable adhesive 3 is interposed, the photo-curing treatment is performed by irradiating with ultraviolet rays, for example. This ultraviolet irradiation can be performed by an ultraviolet light source 60 such as a metal halide or a high pressure mercury lamp.

In the present invention, this photocuring treatment is the first
Light irradiation from the substrate 1 side and light irradiation from the second substrate 2 side. For example, first, ultraviolet irradiation is performed from the first substrate 1 side, and then at least 2 is irradiated from the second substrate 2 side.
Ultraviolet irradiation can be performed once, or light irradiation from both substrates can be performed simultaneously.

For example, first, as shown in FIG. 4, a first substrate
Ultraviolet irradiation is performed from the 1st side. Ultraviolet irradiation amount at this time
Depends on the sensitivity of the photocurable adhesive 3, but is 1 J /
cm ^TwoCan be used as the integrated light amount. That is, this
From the ultraviolet light of the amount of light, the first substrate 1 and the semitransparent film 13
UV of the amount of light after subtracting the amount of light absorbed or reflected
The line contributes to the curing reaction of the photocurable adhesive 3.
You.

Next, as shown in FIG. 5, the photocurable adhesive 3
The first and second substrates 1 and 2 in the state of interposing the substrate are inverted, and then, for example, irradiation of ultraviolet rays is performed by the same method as described above to form the transparent intermediate film 33, and finally the optical recording medium, For example, an optical disc is formed. At this time, the light irradiation energy of the amount of ultraviolet light irradiated from the second substrate side can be adjusted differently depending on the progress of the curing reaction of the photocurable adhesive 3.

As described above, the photo-curing process is performed from both the first substrate 1 side and the second substrate 2 side from both outsides.
Since the photocurable adhesive 3 can be sufficiently photocured even at a position away from the surface irradiated with ultraviolet rays, the photocurable adhesive 3 can be photocured unevenly. Could be done without.

In addition, as compared with the case where the ultraviolet irradiation is performed only from the first substrate 1 side, when the ultraviolet irradiation is performed from both the first and second substrates, the light amount of the ultraviolet light irradiated to each substrate is increased. Since it is possible to reduce the damage to the substrate due to the irradiation of ultraviolet rays, it is possible to effectively prevent the deformation of the substrate and effectively prevent the occurrence of recording and reproducing errors. I was able to avoid it.

In the above example, the first and second information recording layers are formed simultaneously with the molding of the substrate by injection molding.
The case of forming an optical recording medium having a configuration in which the substrates of (1) and (2) are bonded together with the information recording layers on the inside has been described, but the present invention is not limited to this example, and the information recording layer surface of one substrate is The side and the surface opposite to the surface on which the other information recording layer is formed are matched with each other via a photocurable adhesive,
It can also be applied to the case of manufacturing an optical recording medium having a laminated structure.

The present invention also provides a first substrate or a second substrate.
It is also applicable to the case where one of the substrates is a so-called smooth plate on which an information recording layer is not formed, and these substrates are matched with each other through a photo-curable adhesive to manufacture an optical recording medium having a laminated structure. can do.

The present invention also forms a multilayer optical recording medium in which three or more layers are formed as a whole by forming a multilayer information recording layer by the 2P method on the information recording layer formed by the above-mentioned injection molding. It can also be applied in cases.

In the above embodiment, 2
In a two-layer optical recording medium, a structure in which a semitransparent film is formed on one information recording layer and a reflective film is formed on the other information recording layer of two optical recording medium substrates will be described. However, the present invention is not limited to this,
In a two-layer optical recording medium, a reflective film is formed on each information recording layer of two optical recording medium substrates, and information is recorded or read by light irradiation from each optical recording medium substrate side. It is also applicable to the case of obtaining a so-called double-sided read type optical recording medium.

Further, as described above, in the present invention, the optical disc, that is, the fine unevenness contains the data information.
The present invention is not limited to this case, and information recording such as a magneto-optical recording layer or a phase change recording layer that causes a phase change by light irradiation, in which fine irregularities have pregrooves or pits for tracking, addresses, etc. The present invention can also be applied to the case of obtaining an optical recording medium with layers, and in this case, a structure in which a magneto-optical material or a phase change material is formed in a layer on which fine irregularities are formed or a layer above the layer can be adopted.

Further, in the above-mentioned example, the case where the first substrate 1 and the second substrate 2 are disks was mainly described, but the present invention is not limited to this example, and various kinds of cards and the like can be used. The structure can be applied.

[0038]

According to the present invention, two optical recording medium substrates are aligned on the main surface side having each information recording layer with a photo-curable adhesive interposed therebetween, and the light of the photo-curable adhesive is adjusted. By performing the curing treatment by irradiating light from both outer sides of the two substrates for optical recording medium, the photocurable adhesive can be photocured without unevenness, which is highly reliable and long-lasting. An optical recording medium with a long life could be obtained.

Further, since the amount of ultraviolet rays applied to the substrate itself can be reduced as compared with the conventional one, it is possible to prevent the substrate from being damaged, thereby preventing abnormal deformation of the substrate. It was possible to effectively avoid the occurrence of an error.

[Brief description of drawings]

FIG. 1 shows a schematic cross-sectional view of a multilayer optical recording medium.

FIG. 2 shows one manufacturing process of a multilayer optical recording medium.

FIG. 3 shows one manufacturing process of a multilayer optical recording medium.

FIG. 4 shows one manufacturing process of a multilayer optical recording medium.

FIG. 5 shows one manufacturing process of a multilayer optical recording medium.

[Explanation of symbols]

1 1st board | substrate, 1h, 2h center hole, 2 2nd board | substrate, 3 photocurable adhesive agent, 11 1st information recording layer, 1
2 second information recording layer, 13 semi-transparent film, 14 reflective film,
21 first fine unevenness, 22 second fine unevenness, 33
Transparent intermediate film, 50 rotary chuck, 51 central axis of rotary chuck, 52 horizontal base 60 light source

Claims (5)

[Claims] 1. A method of manufacturing an optical recording medium, wherein at least one of the substrates for optical recording medium has an information recording layer, and the main surface sides having the respective information recording layers are opposed to each other so as to face each other. The two optical recording medium substrates are matched by interposing a photocurable adhesive between the bonding, and the photocuring treatment of the photocurable adhesive is performed on the two optical recording medium substrates. A method for manufacturing an optical recording medium, characterized in that the irradiation is performed from both outer sides. 2. The photocurable adhesive comprises a liquid photocurable adhesive interposed between the two optical recording medium substrates,
The method for producing an optical recording medium according to claim 1, wherein the substrate for optical recording medium is stretched to a uniform film thickness between the substrates for optical recording medium by high-speed rotation. 3. The information recording layer according to claim 1, wherein a semitransparent film is formed on one information recording layer of the two optical recording medium substrates, and a reflective film is formed on the other information recording layer. 2. The optical recording medium according to claim 1, wherein recording or reading light for a layer is obtained by irradiating light from the optical recording medium substrate side on the side where the semitransparent film is formed. Recording medium manufacturing method. 4. The light irradiation energy from the optical recording medium substrate side is different from each other.
3. The method for producing an optical recording medium according to item 1. 5. A reflection film is formed on each of the information recording layers of the two substrates for optical recording media, and recording or reading light to the information recording layers is transmitted from the side of each of the substrates for optical recording media. The method for producing an optical recording medium according to claim 1, wherein the optical recording medium is obtained by irradiation.