JPH03176834A - Optical disk - Google Patents

Abstract

PURPOSE:To allow production of diversified kinds in a small amount with relatively simple process by constituting the optical disk of an information recording layer consisting of a specific photopolymer agent for replicas and a replica substrate for holding the information record. CONSTITUTION:The photopolymer agent for replicas consists of the 1st polymer which is the acrylate or methacrylate expressed by formula I and contg. no polar group and benzene ring, the 2nd monomer which is the acrylate or methacrylate expressed by formula II and having low shrinkability on curing and the 3rd monomer which is the acrylate or methacrylate expressed by formu la III and having a low dilution viscosity, and a photopolymn. initiator of 1 to 10wt.% of the entire part. The weight rations of this photopolymer agent are the 1st monomer:the 2nd monomer:the 3rd monomer=5 to 30:20 to 70:10 to 60. This optical disk consists of the information recording layer consisting of the above-mentioned photopolymer agent and the replica substrate which holds the information recording layer. In the formula I, R1 is H or CH3; m is 1 to 3 integer; (a) is 1 to 6 integer; (b) is 0 to 6 integer; the sum of (a) and (b) is 6. The production process is simplified in this way and the production of diversified kinds in a small amount is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to optical discs such as video discs and compact discs.

BACKGROUND ART Conventionally, as a method for manufacturing an optical disc, a method as shown in the flowchart of FIG. 5 has been known.

According to this manufacturing method, first, as shown in FIG. 6(a), a photoresist layer 2 is uniformly formed on the main surface of the glass disk 1.
A photoresist master disk having been formed thereon is prepared, and in a laser cutting step So, a latent image of a spot array corresponding to predetermined information is formed in a spiral or concentric shape on the photoresist layer 2 using a laser beam La.

Next, in the developing step S1, the exposed photoresist master disk is mounted on a developing device and developed, thereby forming a row of minute irregularities (hereinafter referred to as pits) corresponding to the signal to be recorded on the photoresist master disk, A photoresist layer 2 having pits, which is an information recording layer, as shown in FIG. 6(a2)
A developing master disk consisting of the glass disk 1 and the glass disk 1 is obtained.

Next, in a post-baking step S2, the photoresist layer 2 of the development master is dried and fixed on the glass disk 1 to obtain a dry master as shown in FIG. 6(b).

Next, in a silver sputtering step S3, silver is sputtered to form a silver conductive film 3 on the photoresist layer 2, thereby obtaining a laminated mastering master 3a as shown in FIG. 6(C). In this manner, the information recording surface having pits is made conductive by sputtering metal onto the photoresist layer having pits. The above process is the mastering master creation process.

Next, regarding the N1 stamper creation process, first in the Ni electroforming process S4, the obtained mastering master is immersed in a nickel electroforming bath and nickel (Nl) is plated on the silver conductive film 3 to form a thick nickel Layer 4, ie, a nickel stamper, is formed to obtain a structure as shown in FIG. 6(d).

Next, in the stamper separation step S5, as shown in FIG.
As shown in the figure, the stamper, which is the nickel layer 4, is separated from the glass disk 1.

Next, in a photoresist stripping step S6, the photoresist layer 2 remaining on the nickel layer 4 is stripped off, as shown in FIG.
A structure as shown in f) is obtained.

Alkaline solutions or commercially available organic solvents are used to remove photoresists.

Next, in a silver peeling step S7, the silver conductive film 3 is peeled off from the nickel layer 4, and in a stamper processing step S8, the periphery of the nickel layer 4 obtained is processed to form a nickel stamper as shown in FIG. 6(g). get.

The above process is the nickel stamper manufacturing process.

Next, before starting the injection molding process as a replica production process, as shown in FIG. 6(h), a nickel stamper is attached to a predetermined position of the injection molding apparatus 5 (stamper attachment process S9).

Next, as shown in FIG. 6(i), after the mold is clamped, the injection molding device 5 is operated to inject molten transparent resin materials such as PMMA (polymethacrylate-1-) and PC (polycarbonate) onto the nickel stamper. After the resin material has hardened, it is taken out to create an optical disk replica having a predetermined information recording surface as shown in FIG. 6(j) (injection molding step 510). The above process is the replica creation process.

For the thus obtained replica, a reflective film of aluminum or the like is formed on the information recording surface of the replica by a known method (S11), and a protective film is further overcoated on the reflective film (S12). ), an optical disc is formed. In addition, two of these optical discs are pasted together (31
3) After a finishing process (S14), the disc is usually made into a double-sided optical disc.

In such conventional manufacturing methods, optical disks are formed by injection molding of replicas, and are made of molten PMMA or PC.
etc. are used as molding materials. In order to manufacture optical discs made of molten molding material, the stamper is made of nickel (Ni), which has excellent durability even in injection molding. For this reason, as described above, the number of electroforming steps is large and plating takes time until the nickel stamper is manufactured. In addition to the injection molding equipment, the electroforming tank is also large, so the factory equipment becomes large-scale. Therefore, there is a problem that the manufacturing cost of the optical disc increases. Conventional optical discs have no problem in mass production, but they are not suitable for producing optical discs that are compatible with the recent small-volume production of a wide variety of video and audio software.

Summary of the Invention [Object of the Invention] An object of the present invention is to provide an optical disk suitable for small-lot, wide-variety production and mass production using a relatively simple process.

[Structure and operation of the invention] In the optical disc according to the present invention, R1 is H or CH3, m is an integer from 0 to 3, a is an integer from 1 to 6, and b is an integer from 0 to 6. , the sum of a and b is 6. A first monomer which is a polyfunctional acrylate or methacrylate without polar group benzene group represented by the following formula (B1), wherein the sum of a and b is 6. A second monomer which is 1. and a third monomer which is a diluted low viscosity acrylate or methacrylate represented by the following formula (B3) where R is H or CH3.
monomer, R1 is H or CH3, R2 is -0C9H,,
CO-, and the sum of m and n is an integer from 2 to 10 (m
≧1. represented by the following formula (B2) where n≧1), and a photopolymerization initiator in an amount of 1 to 10 vt% of the total, and the weight ratio of the first, second, and third monomers is the first monomer. Monomer: Second monomer: Third monomer = 5-30: 20-70: information recording layer 0 consisting of a photopolymer agent for replicas having a ratio of 10-60; a silver layer; and a replica substrate holding the information recording layer. Features.

Here, the photopolymer agent is a substance that hardens from a fluid to a solid upon irradiation with radiation such as ultraviolet rays.

This replica photopolymer agent has an -OH group.

Since it does not use monomers containing polar groups such as COOH groups and -NH groups, it has high releasability to resin standbars. A replica made of a monomer having a similar molecular structure to the component monomer of the resin stamper has poor releasability from the resin stamper. For this reason, photopolymer agents for replicas use monomers that have a different molecular structure from the component monomers of the resin stamper.

Since the main component monomer of the resin stamper has a benzene skeleton, the photopolymer agent for the replica uses a system that does not contain a benzene skeleton, such as an aliphatic monomer or an alicyclic monomer.

Moreover, the photopolymer agent for replicas described above has excellent curability. In order to improve curability, a 2- to 6-functional polyfunctional monomer is used as the first monomer in the pho-11 polymer agent.

Furthermore, the photopolymer agent for replicas has a low curing shrinkage rate and excellent adhesive strength with the PMMA substrate.

A low shrinkage monomer is used as the second monomer in order to suppress the curing shrinkage rate. This is because the skeleton of the second monomer R2 in the formula (B2) suppresses shrinkage during curing. By containing this low-shrinkage monomer, the replica photopolymer agent has improved adhesive strength with the PMMA substrate of the replica substrate. This is because the occurrence of misalignment between the two during curing is reduced. Since the photopolymer agent has the function of lowering the elastic modulus, it has good peelability and transferability from the resin stamper.

Furthermore, since the photopolymer agent for replicas described above contains an aliphatic diluent monomer as the third monomer, the filtration rate is high. This is because it is necessary to reduce the viscosity of the monomer in order to improve the filtration speed and transfer accuracy. The viscosity can be adjusted by changing the composition ratio of the diluting monomer. Even if an aliphatic or 2-like alicyclic monomer is used as the third monomer, it is desirable because it has low absorption in the ultraviolet region and the photopolymer agent layer of the resin stamper has excellent light resistance (iJ discoloration). Further, the weight ratio of the first, second and third monomers is preferably in the range of 5 to 30:20 to 70:10 to 60 (first monomer: second monomer: third monomer).

Here, in the resin stamper resin stamper-use resin stamper agent that has high releasability to the metal forming the resin stamper, R1 is H or CH, and R2 is CH.

CH2CH20- or -CH2CHO-, m
and the sum of n is an integer of 2 to 10 (m≧l, n≧1), a main component monomer which is a benzene ring-containing bifunctional acrylate or methacrylate represented by the following formula (AI), and R1 is H or CH, where k is an integer of 1 to 8, and g is an integer of 3 to 8, a subcomponent monomer that is a fluorine-containing monofunctional acrylate or methacrylate represented by the following formula (A2); 1 to 10 wL% of a photopolymerization initiator to .1 is a photopolymer agent.

The photopolymer agent for standbars, which is highly removable to the above-mentioned metals, has hydrophobicity because the fluorine and benzene rings are nonpolar. As described above, since the molecular structures of the sub- and main component monomers include the hydrophobic atomic groups and molecular skeletons of 4 fluorine and benzene rings, photopolymer agents for stampers are desirable because they have high releasability to metals after curing. . Further, the fluorine-containing monomer as a subcomponent is more effective in terms of hydrophobicity if the fluorine atoms are oriented on the surface of the photopolymer agent layer. Therefore, the fluorine-containing monomer is preferably monofunctional. This is to free fluorine in the crosslinked structure. This fluorine-containing monomer also improves releasability from the photopolymer agent that forms the replica during replica creation.

Furthermore, the photopolymer agent for stampers described above improves the transferability during development of the photopolymer agent in the transfer step. That is, the fluorine-containing monomer also has a function as a surfactant, and has the effect of improving wettability with metal films such as silver and aluminum, and lowering the dynamic contact angle during transfer. This also prevents the generation of voids and improves transfer accuracy after curing. On the other hand, since the surface tension of the photopolymer side threads decreases, the filtration rate increases compared to monomers of the same viscosity.

5 Furthermore, the photopolymer agent for stampers has durability as a stamper and has a low curing shrinkage rate. the above(
This is because the main component monomer skeleton of R2 in formula A1) suppresses shrinkage during curing. Furthermore, in order to provide durability, the main component monomer needs to be crosslinked. However, for crosslinking, it is necessary to use a polyfunctional (bifunctional or higher) monomer as the main component monomer, but while trifunctional or higher functional monomers increase the curing speed, they also significantly increase the curing shrinkage rate, lower transfer accuracy, and reduce cupping. The adhesive strength with the ring decreases. Therefore, the bifunctional monomer is the most well-balanced main component monomer.

Furthermore, since the photopolymer agent for the stamper contains a low-viscosity monomer, such as a photopolymerization initiator, at less than 10% by weight, it does not attack the photoresist of the mastering master. Low viscosity monomer (regardless of the type of monomer, 1
This is because photopolymer side yarns containing 10vt, % or more of (00 cps or less) tend to attack the photoresist.

Furthermore, the above photopolymer agent for stampers has good UV curability. The main component monomer having a benzene skeleton exhibits strong absorption in the ultraviolet region, so in a thin film (photopolymer agent layer), the ultraviolet absorption efficiency is high,
Increases curing speed with UV light.

The weight ratio of the main component monomer to the subcomponent monomer is 90 to 99.9:]0 to 0.
It is desirable that the number be within the range of 1.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows a diametrical cross-sectional view of a resin stamper according to the invention. The resin stamper 13a consists of an information recording layer of a stamper photopolymer agent 11 and a glass disk 13 which is a stamper substrate supporting the information recording layer. Furthermore, FIG. 2 shows a diametrical cross-sectional view of an optical disk replica manufactured from a resin stamper according to the present invention. The optical disk replica 23a includes an information recording layer made of a replica photopolymer agent 21 and a PMMA disk 23 that is a replica substrate supporting the information recording layer.
It consists of.

FIG. 3 shows a flowchart 7 of the manufacturing process of an optical disk replica using the resin stamper according to the present invention.

In this manufacturing process, steps up to the silver sputtering step S3 for obtaining a mastering master are carried out in the same manner as in the conventional method shown in FIG. The optical disc manufacturing process of this embodiment differs from the conventional method in the process of manufacturing a nickel stamper and a replica.

First, in the stamper manufacturing process, using the so-called 2P transfer method in which a cured photopolymer agent is used as a transfer layer, information is recorded using a photopolymer agent for the stamper using the silver-coated mastering master obtained in the silver sputtering process S3 as a mold. The surface is transferred onto a stamper substrate, that is, a glass plate, and a resin stamper is formed instead of a nickel stamper.

Specifically, the 2P transfer method uses a mask ring master 3a whose information recording surface is coated with a metal film, as shown in FIG. 4(a).
is placed horizontally on the table 10 of the transfer device so that its information recording surface faces upward (master fixing step 521).

After that, as shown in FIG. 4(b), the mastering master 3
On the information recording surface of a, a liquid photopolymer agent 11 for a stamper with high releasability is applied to the metal film (photopolymer agent supply step 522).

Next, as shown in FIG. 4(c), a transparent glass disk 13 coated with a silane coupling agent 12 as a substrate pretreatment is placed on a stamper substrate jig 14 of a transfer device.
While keeping the jig 14 horizontal, lower the jig 14, place it concentrically on the mastering master disk 3a via the stamper photopolymer agent 11, position it, and place the stamper on the entire space between the glass disk 13 and the mastering master disk 3a. Photopolymer agent 11
(photopolymer agent development step 823).

Thereafter, as shown in FIG. 4(d), the stamper photopolymer agent 11 is cured by irradiating ultraviolet rays (arrow) from the glass disk 13 side to the stamper photopolymer agent 11, and is coated on the main surface of the glass disk 13. An information recording layer made of a photopolymer agent for a cured stamper is formed or transferred (ultraviolet irradiation step 524).

Next, as shown in FIG. 4(e), the mask ring master 3a
By peeling off the glass disk 13 together with the information recording layer of the photopolymer agent for stamper from the stamper film 9, a resin stamper 13a consisting of the information recording layer of the photopolymer agent 11 for stamper and the glass disk 13 supporting it is obtained (peeling step 525). In this resin stamper manufacturing process, a so-called 2P transfer device that executes a conventionally known 2P transfer method is used, and the process from fixing the mask ring master 3a to taking out the resin stamper 13a is automatically performed.

Subsequently, a replica is manufactured using the obtained resin stamper 13a as a mold. This replica manufacturing process does not involve conventional injection molding using molten PMMA and PC, but uses a 2P transfer method and equipment similar to the resin stamper manufacturing process described above to transfer the information recording surface onto a replica substrate, that is, a hardened PMMA substrate, using a replica photo. An optical disk replica is formed by transferring with a polymer agent.

Specifically, as shown in FIG. 4(f), the obtained resin stamper 13a is placed horizontally on the table 10 of the transfer device so that its information recording surface faces upward (stamper fixing step 526).

Thereafter, as shown in FIG. 4(g), a liquid replica photopolymer agent 21 having high releasability with respect to the cured stamper photopolymer agent 11 is applied onto the information recording surface of the resin stamper 13a. (Photopolymer agent supply step 5
27). Next, as shown in FIG. 4(h), a transparent PMM was coated with a silane coupling agent 12 as a substrate pretreatment.
Place the A plate 23 on the stamper substrate jig 14 of the transfer device P
Lower the jig 14 while keeping the MMA board 23 at board 3, and place the replica photopolymer agent 21 on the resin stamper 13a.
PMMA board 2 is placed concentrically through the
Spread the replica photopolymer agent 21 all over the space between the three stampers 13a (photopolymer agent development step 5)
28). Thereafter, as shown in FIG. 4(i), ultraviolet rays (arrow) are irradiated from the PMMA board 23 side to the replica photopolymer agent 21 to harden the replica photopolymer agent 21, and the PMMA board 23 is placed on the board 3. Forming or transferring an information recording layer made of a photopolymer agent for a cured replica (
Ultraviolet irradiation step 529). Next, as shown in FIG. 4(j), from the resin stamper 13a, the PMMA disk 2 together with the information recording layer of the photopolymer agent for the replica.
3, a so-called 2P replica of the optical disk replica 23a1, which is the information recording layer of the replica photopolymer agent 21 and the PMMA disk 23 supporting the information recording layer 3, is obtained (peeling step 530). Even in this 2P replica manufacturing process, 2P
A transfer device is used to automatically perform the process from fixing the resin stamper 13a to removing the resin stamper.

The thus obtained replica is manufactured by forming a reflective film of aluminum or the like on the information recording surface of the replica using a known method, and then overcoating the reflective film with a protective film. Two replicas are pasted together and a finishing process is performed to obtain a double-sided optical disc.

Effects of the Invention As described above, according to the optical disc of the present invention, it is possible to obtain an optical disc made of a photopolymer agent that has high releasability to a resin stamper made of a photopolymer agent that has releasability to metals. Therefore, in the optical disc manufacturing process, replicas can be created using the 2P transfer method from the resin 2 stamper, and furthermore, the optical disc manufacturing process can be simplified while achieving accurate transfer of the information recording surface. To facilitate the manufacture of optical discs compatible with a wide variety of video and audio software.

Example Photopolymer agent for stamper In general formula (A1), R+ = CH3, R2 = -CH2CH2-0-m+
97 parts by weight of methacrylate monomer which is n-6, R+=H in general formula (A2).

Mix 3 parts by weight of acrylate monomer with K-1, F = 3 and 2 parts by weight of benzophenone and 1-hydroxycyclohexyl ketone as photopolymerization initiators to obtain a viscosity of 400 cp.
A solution of s was prepared.

After pouring this solution in a ring shape around the periphery of the master link master disk 3a whose information recording surface is coated with silver according to the process shown in FIG. A stamper photopolymer agent 1 is pressed between the glass disk 13 and the mastering master disk 3a so that the distance is 150 μm.
1 over the glass plate 13, then place a metal noride lamp (5
The photopolymer agent 11 was cured by irradiating ultraviolet rays with a line of ff 1150 nJ/c+# (wavelength: 365 nm) at a wavelength of 0 W/cm.

Next, the glass disk 13 was peeled off from the mastering master disk 3a to create a resin stamper 13a having an information recording layer made of photopolymer.

Subsequently, a photopolymer agent for replicas (0V-1,022 manufactured by Hitachi Chemical Co., Ltd.) was poured in a ring shape onto the obtained resin stamper 13a, and then a transparent PMM with a thickness of 1.2 mm was poured.
Press A board 23 so that the distance between boards 3 is 50μ, PM
The photopolymer agent 21 for replica is spread between the three resin stampers 13a between the MA boards 23, and then the PMMMA board 2.
3 Line from above ff1150 mJ/am (wavelength 3B5
The photopolymer agent 21 was cured by irradiating the photopolymer agent 21 (nm).

Next, from the resin stamper 13a to the PMMA board 23
An optical disk replica 23a having an information recording layer made of photopolymer was obtained.

As a result, the optical disk manufacturing method using the resin stamper of the present invention is about half or less of the conventional manufacturing method in which a nickel stamper is created by electroforming and a replica is created from the nickel stamper by injection molding. It was possible to manufacture a replica of an optical disc in just a few hours.

[Brief explanation of drawings]

FIG. 1 is a diametrical cross-sectional view of a resin stamper according to the present invention;
FIG. 2 is a diametrical cross-sectional view of an optical disk replica manufactured from the resin stamper according to the present invention, FIG. 3 is a flowchart showing the main steps of the method for manufacturing an optical disk using the resin stamper according to the present invention, and FIG. 3 is a schematic sectional view of members in the 2P transfer step, FIG. 5 is a flowchart showing a conventional optical disc manufacturing method, and FIG. 6 is a schematic sectional view of members in each step of FIG. 5. Explanation of symbols of main parts 3a...Mastering mastering disc 11...Stamper photopolymer agent 13...
... Glass disk 21 ... Photopolymer agent for replica 5 23 ... PMMA disk

Claims (1)

[Claims] R_1 is H or CH_3, m is an integer from 1 to 3, a is an integer from 1 to 6, b is an integer from 0 to 6, and the sum of a and b is 6, the following formula (B1
) The first monomer is a polyfunctional acrylate or methacrylate that does not contain a polar group benzene ring. R_1 is H or CH_3, R_2 is -OC_
5H_1_0CO-, and the sum of m and n is 2 to 1
The second monomer is an acrylate or methacrylate with low shrinkage during curing, represented by the following formula (B2), which is an integer of 0 (m≧1, n≧1), ▲There are mathematical formulas, chemical formulas, tables, etc.▼...( B2) and a third diluted low viscosity acrylate or methacrylate represented by the following formula (B3) where R is H or CH_3
There are monomers, ▲mathematical formulas, chemical formulas, tables, etc.▼...(B3) and 1 to 10 wt. % photopolymerization initiator, and the weight ratio of the first, second and third monomers is: first monomer: second monomer: third monomer = 5-30:20-70:10-60. Information recording layer made of photopolymer agent for replicas,
and an optical disc comprising a replica substrate holding the information recording layer.