JP2003067975A - Laminated optical recording medium and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated optical recording medium and its manufacture method capable of completely curing the resin in a short time without deformation due to heat. SOLUTION: Since at least one of the optical recording layers formed on a first and second plates consists of a metal layer mainly containing Ag, the ultraviolet ray irradiated to the plate can be controlled when curing the ultraviolet-ray curable resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a bonded optical recording medium and a method for manufacturing the same.

[0002]

2. Description of the Related Art Among optical disk recording media, a bonded optical recording medium manufactured by bonding two substrates is
Generally as a hot-melt adhesive,
UV curable resin, double-sided adhesive sheet, etc. are used. When a substrate such as a DVD disc is thin and strength is required to be secured, it is desirable to use an ultraviolet curable resin because the adhesive reliability and the optical characteristics of the adhesive layer after adhesion are good. Further, it is desirable to use an ultraviolet curable resin from the viewpoint of little damage to the organic dye recording material of the write-once type optical recording medium at the time of curing.

Adhesion using the ultraviolet curable resin is
It is carried out by applying an ultraviolet curable resin to one of the two substrates, bonding the substrates via the ultraviolet curable resin, and then irradiating ultraviolet rays from either one of the substrates to cure the resin.

[0004]

However, when an optical recording medium is prepared by bonding two substrates having an optical recording layer made of a metal layer to each other by an adhesive method such as the above method, irradiation in the curing step is performed. Since the ultraviolet rays are reflected and absorbed by the optical recording layer, the ultraviolet ray amount irradiated on the ultraviolet curable resin is remarkably reduced as compared with the incident ultraviolet ray amount. As a result, the resin curing step is either a short-time treatment by high-intensity UV irradiation or a long-term treatment by low-intensity UV irradiation. In this case, the former causes problems such as medium deformation and recording film damage due to UV heating due to high illuminance, and the latter causes problems such as resin uncured portion generation and throughput reduction due to long-time processing due to low illuminance.

Therefore, an object of the present invention is to provide a bonded type optical recording medium which does not have the above problems and a method for manufacturing the same.

[0006]

A bonded optical recording medium according to the present invention comprises a first substrate on which at least one first optical recording layer is formed and at least one second optical recording layer. A second substrate which is a bonding type optical recording medium in which the first and second optical recording layers are bonded to each other via an ultraviolet curable resin layer so as to face each other. At least one of the optical recording layers is made of a metal layer containing Ag as a main component.

Further, in the method of manufacturing the bonded optical recording medium according to the present invention, the first substrate having at least one first optical recording layer and the second optical recording layer having at least one layer are formed. A method for manufacturing a bonded optical recording medium, wherein two substrates are bonded together via an ultraviolet curable resin layer so that the first and second optical recording layers face each other, and at least one substrate is formed on the first substrate. A first step of providing a first optical recording layer of a layer, a second step of providing at least one second optical recording layer on a second substrate, and the first substrate and the second substrate with an ultraviolet curable resin. And a third step of laminating, wherein at least one of the first and second optical recording layers is made of a metal layer containing Ag as a main component.

According to the bonded optical recording medium and the method for manufacturing the same of the present invention, at least one of the optical recording layers formed on the first substrate and the second substrate is Ag.
Since it is composed of a metal layer containing as a main component, it is possible to suppress the dose of ultraviolet rays irradiated toward the substrate during curing of the ultraviolet curable resin, and in a short time without causing thermal deformation of the medium. The resin can be completely cured.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A bonded optical recording medium and a method for manufacturing the same according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an optical recording medium according to the present invention,
It is a figure which shows the Example of the two-layer optical recording medium which stuck together two board | substrates with which the optical recording layer was produced one by one. The two-layer optical recording medium 1 includes a first disc having a first optical recording layer 3 formed on a first transparent substrate 2 and a second disc having a second optical recording layer 5 formed on a second transparent substrate 6. Consists of. First
The transparent substrate 2 and the second transparent substrate 6 are bonded together by the ultraviolet curable resin 4 so that the first optical recording layer 3 and the second optical recording layer 5 face each other.

The first transparent substrate 2 is approximately 0.1 to 1.2 mm.
Thickness of acrylic resin, polycarbonate (P
C) A resin, a resin material such as a polyolefin resin, or a transparent material such as a glass material. For resin materials,
PC resin is preferable in terms of moldability, water absorption, heat resistance, and the like. A pit pattern (unevenness) according to an information signal is formed on the first transparent substrate 2.

The first optical recording layer 3 is a non-rewritable optical recording layer and is, for example, a metal layer of Au, Al, Al alloy or the like.
The first optical recording layer 3 is, for example, a write-once optical recording layer made of an organic dye material such as cyanine or phthalocyanine, or an alloy material of a low melting point metal such as Te, Bi, Se or Sn, or Ge.
It is also possible to form a phase change type optical recording layer using an InSbTe system, AgInSbTe system, GeSbTe system, or the like as a recording layer.

The ultraviolet curable resin 4 is made of an ultraviolet curable resin, and is preferably an acrylic ultraviolet curable resin from the viewpoint of waterproofness. The second optical recording layer 5 is composed of a metal layer containing Ag as a main component. The metal layer containing Ag as a main component is Ag or an Ag alloy and is disclosed in, for example, US Pat.
No. 007,889, Ag _{100- (X + Y)} Pd _X Cu
_Y (X: about 0.1 to 15 atm%, Y: about 0.01 to 1)
0 atm%) metal layer, or Ag-Nd-Cu system, Ag
It is a metal layer such as -Nd-Au system. The metal layer containing Ag as a main component preferably has an ultraviolet transmittance of 20% or more and a laser light reflectance of 30% or more from the transparent substrate side. The reason why the ultraviolet ray transmittance is 20% or more is that it is possible to efficiently irradiate the ultraviolet ray curable resin with ultraviolet rays at the time of curing and to suppress the integrated irradiation amount of the medium to be small. The reason why the laser light reflectance is 30% or more is that
This is because a sufficient reproduction output can be obtained. The laser beam reflectance is preferably 70% or more in order to obtain compatibility between the obtained laminated recording medium and a CD.

The thickness of the metal layer is preferably about 25 to 150 nm. More preferably 25 to 50n
It is about m, and most preferably 30 to 40 nm.
This is because it is possible to obtain the characteristics that the ultraviolet transmittance is 20% or more and the laser light reflectance is 30% or more. The first optical recording layer 3 may be an optical recording layer containing Ag as a main component, which is similar to the second optical recording layer 5.

The second transparent substrate 6 is the first transparent substrate 2 described above.
The same pit pattern (unevenness) is formed according to the information signal by using the same material as. The above is the configuration of the two-layer optical recording medium according to the present invention. This two-layer optical recording medium is laser light from either the first transparent substrate 2 side or the second transparent substrate 6 side, or both transparent substrates. Can be irradiated.

Next, an embodiment of a method for manufacturing a two-layer optical recording medium according to the present invention will be described with reference to the flow chart shown in FIG. First, a first transparent substrate 7 and a second transparent substrate 9 having a pit pattern on one surface are prepared by injection molding or the like of PC resin or the like. Then, a metal layer of Al or Al alloy is formed on the pit pattern of the first transparent substrate by a film forming method such as sputtering, physical vapor deposition (PVD) such as ion plating, or chemical vapor deposition (CVD) such as plasma CVD. Therefore, the first optical recording layer 8 made of, for example, an Al—Ti alloy is formed and used as the first disk.

On the other hand, on the pit pattern of the second transparent substrate 9, a metal layer of Ag or Ag alloy, for example, Ag _{100- (X + Y)} Pd _X Cu _Y (X: About 0.1 to 15 atm%, Y: About 0.01 to 10 atm
%) To form a second optical recording layer 10, which will be referred to as a second disc. The first optical recording layer 8 may be a metal layer of Ag or Ag alloy, or may be a write-once type optical recording layer or a phase conversion type optical recording layer.

After forming the first and second discs, the ultraviolet curable resin 11 is uniformly applied on the first optical recording layer 8 of the first disc by a spin coating method to a thickness of about 20 to 30 μm on the substrate surface. The first optical recording layer 8 of one disc and the second optical recording layer 10 of the second disc are laminated and laminated so as to face each other. The method of applying the resin is not limited to the spin coating method as long as the resin can be applied to a uniform thickness, and for example, a screen printing method may be used. Although a liquid ultraviolet curable resin is used here, the present invention is not limited to this, and a film-shaped resin may be used, for example. Also, the method of bonding is not limited to this method,
It is also possible to adopt a spin bonding method in which the second disk is superposed after the resin is applied on the first disk, and this is rotated at a high speed to uniformly distribute and bond the resin.

After the bonding, ultraviolet rays are irradiated from the side of the second transparent substrate on which the second optical recording layer, which is a metal layer of Ag or Ag alloy, is formed, and the resin is cured to complete the two-layer optical recording medium. As a modification, for example, when the first optical recording layer is a metal layer of Ag or Ag alloy, it is possible to perform the ultraviolet irradiation from the first substrate side. Further, a modification in which irradiation is performed from both directions on the first substrate side or the second substrate side is also possible.

Other examples of the irradiation method of ultraviolet irradiation are possible, and for example, there is a two-step ultraviolet irradiation method as shown in FIG. First, an optical recording layer is formed on each of two substrates each having a circular through hole provided in the center of the transparent substrate. At least one of the optical recording layers of the two substrates is A
A metal layer containing g as a main component. Next, as shown in FIG. 3A, the central position of the transparent substrate is fixed by the substrate alignment member 12 having the same shape as the through hole, and the two sheets of ultraviolet curable resin 13 are interposed so that the optical recording layers face each other. Laminate the transparent substrates. At this time, the transparent substrate 14 having the optical recording layer containing Ag as a main component is placed on the UV irradiation side. After that, the outer peripheral portion of the substrate is masked with the ultraviolet ray opaque member 15, and ultraviolet rays of low illuminance are irradiated to temporarily fix the substrate.

After the temporary fixing, as shown in FIG. 3 (b), the substrate alignment member 12 and the ultraviolet ray opaque member 15 are removed, and then high-intensity ultraviolet ray irradiation is performed to completely cure the resin to complete the optical recording medium. . As a further embodiment of the present invention, FIG. 4 shows an embodiment of a three-layer optical recording medium. The three-layer optical recording medium 16 of FIG. 4 includes a first transparent substrate 17, a first optical recording layer 18a,
Intermediate layer 19, first optical recording layer 18b, ultraviolet curable resin layer 2
0, the second optical recording layer 21, and the second transparent substrate 22 are sequentially laminated.

The manufacturing method of the three-layer optical recording medium 16 is as follows.
A first Al or Al alloy or the like is formed on the pit pattern of the first transparent substrate 17 formed by injection molding of C resin by a film forming method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD).
The optical recording layer 18a is formed. On the first optical recording layer 18a,
An ultraviolet curable resin is applied, a transparent stamper pin serving as a master having a pit pattern is formed, ultraviolet irradiation and stamper peeling are performed to form an intermediate layer 19 for transferring the pit pattern. The first optical recording layer 18b made of Al, Al alloy or the like is formed again on the intermediate layer 19 to form a first disc.

On the other hand, the second optical recording layer 21 which is a metal layer of Ag or Ag alloy is formed on the pit pattern of the second transparent substrate 22 by a film forming method such as PVD or CVD. This is the second disk. An ultraviolet curable resin by spin coating is applied to one of the optical recording layers of the first disc and the second disc, and the optical recording layers are bonded so that the optical recording layers face each other.
After the bonding, UV irradiation is performed from the second transparent substrate 22 side to cure the resin and form a three-layer optical recording medium. The curing by ultraviolet irradiation may be the above-described two-step ultraviolet curing method.

In the above three-layer optical recording medium, the first recording layers 18a and 18b may be metal layers of Ag or Ag alloy. When the first recording layers 18a and 18b are metal layers of Ag or Ag alloy, the ultraviolet irradiation can be performed only from the first transparent substrate 17 side. In addition, the first transparent substrate 17
It is also possible to irradiate from both the side and the second transparent substrate 22 side. Further, the first optical recording layers 18a and 18b may be write-once type optical recording layers or phase change type optical recording layers. Also, different types of optical recording layers may be used. For example, the first optical recording layer 18a
Is a write-once type optical recording layer, the first optical recording layer 18b is a phase change type optical recording layer, the second optical recording layer 21 is a metal layer of Ag or Ag alloy,
It is also possible to make a hybrid type optical recording medium.

The structure of the three-layer optical recording medium and the manufacturing method thereof have been described above. As a further application example, as shown in FIG.
Layered optical recording media are possible. Four-layer optical recording medium 23 of FIG.
Is a first transparent substrate 24, a first optical recording layer 25a, a first intermediate layer 26, a first optical recording layer 25b, an ultraviolet curable resin layer 27,
Second optical recording layer 28a, second intermediate layer 29, second optical recording layer 2
8b and the second transparent substrate 30 are sequentially laminated.

In the method of manufacturing the four-layer optical recording medium 23 as shown in FIG. 5, first of all, a first resin layer is formed by injection molding of PC resin or the like.
A first optical recording layer 25a of Al, Al alloy or the like is formed on the pit pattern of the transparent substrate 24 by a film forming method such as PVD or CVD.
To form. On the first optical recording layer 25a, a first intermediate layer 26 for transferring a pit pattern is formed by applying an ultraviolet curable resin, attaching a transparent stamper pin as a master having a pit pattern formed thereon, irradiating ultraviolet rays and peeling the stamper. Form. On the first intermediate layer 26, a first layer of Al, Al alloy, etc. is formed again.
The optical recording layer 25b is formed and used as the first disc.

Next, a second optical recording layer 28b made of a metal layer of Ag or Ag alloy is formed on the pit pattern of the second transparent substrate 30 by a film forming method such as PVD or CVD. Second
The second intermediate layer 29 is formed on the optical recording layer 28b by the same method as the above-mentioned first intermediate layer 26. A metal layer of Ag or Ag alloy is formed again on the second intermediate layer 29 to form a second optical recording layer 28a, which is used as a second disc.

UV curable resin by spin coating is applied to one of the optical recording layers of the first disk and the second disk,
The optical recording layers are attached so that they face each other. After the bonding, ultraviolet irradiation is performed from the second transparent substrate 30 side to cure the resin and form a four-layer optical recording medium. The curing by ultraviolet irradiation may be the above-described two-step ultraviolet curing method.

In the above four-layer optical recording medium, the first optical recording layers 25a and 25b may be metal layers of Ag or Ag alloy. When the first optical recording layers 25a and 25b are metal layers of Ag or Ag alloy, the ultraviolet irradiation does not affect the first transparent substrate 24.
It is possible only from the side. Irradiation from both the first transparent substrate 24 side and the second transparent substrate 30 side is also possible. Furthermore, the first optical recording layers 25a and 25b may be write-once type optical recording layers or phase change type optical recording layers. Also, different types of optical recording layers may be used. For example, the first optical recording layer 2
5a is a write-once type optical recording layer, the first optical recording layer 25b is a phase change type optical recording layer, and the second optical recording layers 28a and 28b are Ag or Ag.
A hybrid type optical recording medium having an alloy metal layer can be used.

According to the present invention, it is possible to obtain a multilayer optical recording medium having a larger number of optical recording layers. For example, a plurality of layers of metal optical recording layers containing Ag as a main component are provided on one of the two transparent substrates, a plurality of layers of optical recording surfaces are formed on the other transparent substrate, and the substrates are bonded as described above. It is possible to create.

[0030]

According to the bonded optical recording medium and the method of manufacturing the same of the present invention, at least one of the optical recording layers formed on the first substrate and the second substrate is
Since it is composed of a metal layer containing g as a main component, it is possible to suppress the dose of ultraviolet rays applied to the substrate when the ultraviolet curable resin is cured.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a two-layer optical recording medium according to the present invention.

FIG. 2 is a flowchart showing a method for manufacturing a two-layer optical recording medium according to the present invention.

FIG. 3 is a flow chart showing an example of an ultraviolet irradiation step according to the present invention.

FIG. 4 is an enlarged sectional view showing a three-layer optical recording medium according to the present invention.

FIG. 5 is an enlarged sectional view showing a four-layer optical recording medium according to the present invention.

[Explanation of symbols]

1 2 layer optical recording medium 2, 7 First transparent substrate 3, 18a, 18b, 25a, 25b First optical recording layer 4, 11, 20, 27 UV curable resin 5, 21, 28a, 28b Second optical recording layer 6, 9 Second transparent substrate 12 Board alignment member 15 UV opaque material 16 Three-layer optical recording medium 23 4-layer optical recording medium

Claims (7)

[Claims] 1. A first substrate on which at least one first optical recording layer is formed and a second substrate on which at least one second optical recording layer is formed are the first and second optical recording layers. A bonded optical recording medium in which recording layers are bonded to each other via an ultraviolet curable resin layer, wherein at least one of the first and second optical recording layers is A
A bonded optical recording medium comprising a metal layer containing g as a main component. 2. The metal layer containing Ag as a main component has an ultraviolet transmittance of 20% or more and a laser light reflectance of 30.
The bonded optical recording medium according to claim 1, wherein the content is at least%. 3. The film thickness of the metal layer containing Ag as a main component is 25 to 150 nm.
The laminated optical recording medium described. 4. A first substrate on which at least one first optical recording layer is formed and a second substrate on which at least one second optical recording layer is formed are the first and second optical recording layers. A method of manufacturing a bonded optical recording medium, wherein recording layers are bonded to each other via an ultraviolet curable resin layer, the first step of providing at least one first optical recording layer on a first substrate. And a second step of providing at least one second optical recording layer on the second substrate, and a third step of bonding the first substrate and the second substrate with an ultraviolet curable resin. At least one of the 1st and 2nd optical recording layers consists of a metal layer which has Ag as a main component, The bonding type optical recording medium manufacturing method characterized by the above-mentioned. 5. The metal layer containing Ag as a main component has an ultraviolet transmittance of 20% or more and a laser light reflectance of 30.
% Or more, and the method for producing a bonded optical recording medium according to claim 4, wherein 6. The film thickness of the metal layer containing Ag as a main component is 25 to 150 nm.
A method for manufacturing a bonded optical recording medium as described above. 7. The third step comprises a first irradiation step of irradiating a part of the medium with ultraviolet rays of low illuminance, and a second irradiation step of irradiating ultraviolet rays of high illuminance to the entire surface of the medium after the first irradiation step. 5. The method for producing a bonded optical recording medium according to claim 4, further comprising: