JPH10106037A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance joint force with a recording layer joined to this area by surface machining an area from an outside end part to a side surface of a substrate. SOLUTION: This optical information recording medium 1 is a sandwich type constituted so that a disk like substrate 11 provided with a recording layer 13, a reflection layer 14 and a protection layer 15 in this order and having a hole part 10a on its center is stuck to a disk like protection plate 12 with the same shape as this substrate 11 so that the recording layer 13 side becomes the inside respectively through adhesive 16. Then, an area (a corner part that both surfaces are intersected) from the outside end part surface of the substrate having the recording layer 13 to its side surface is chamfered, and the recording layer 13 is joined to the area 17 performed with the chamfering process. Further, also the outside end part of the inside of the disk like substrate 11 is preferred to be chamfered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to two disk-shaped substrates each having a recording layer, a reflective layer and a protective layer in this order, or a disk-shaped protective plate having the same shape as the substrate. The present invention relates to a sandwich-type optical information recording medium capable of recording and reading information by using a laser beam bonded via an adhesive layer such that the recording layer side is inside.

[0002]

2. Description of the Related Art A write-once optical information recording medium (CD-R) has been put to practical use, in which information can be recorded only once, but once written information cannot be erased. This write-once optical information recording medium has been used as a medium that meets the need to be able to provide a CD on which information is recorded in a small number of units of several to several tens at a reasonable price and quickly. . The general structure of this medium is to provide a recording layer made of a dye and a reflective layer made of a metal on a disc-shaped substrate in this order,
Further, a protective layer made of a resin is provided on the reflective layer by coating so as to cover the reflective layer. The surface of the substrate (the interface between the substrate and the recording layer) usually guides the scanning of the laser beam to be irradiated, and has a concave guide groove (generally, a pre-group) so that the laser beam accurately follows the irradiation target position. ) Is formed. However, there is a problem that the above-described structure cannot be said to have sufficiently high durability and cannot sufficiently cope with recent demands for a high recording capacity.

In response to the above demands, a write-once DVD (digital video disc: DVD-R) has recently been developed as an optical information recording medium having a large recording capacity. This write-once optical information recording medium is expected to be extremely useful for storing a large amount of information such as medical charts, electronic libraries of museums and libraries, and official documents. As a basic structure of a DVD-R, for example, a structure shown in FIG. 17 has been proposed (“Nikkei New Media” separate volume “DVD”, published in 1995).
That is, the DVD-R has a disk-shaped substrate 171a on which a guide groove (pre-group) for tracking is formed, an organic dye layer (recording layer) 173a formed on the disk-shaped substrate by spin coating, and further thereon. And a reflective layer 174a and a protective layer 175a in this order (the description of the reference numeral of the other disk is omitted), and the adhesive layer 176 is attached with the recording layer side inside. Since the writing (recording) and reading (reproduction) of information on the DVD-R can be performed from both sides of the substrate of the disc, the information alone is twice as large as that of the CD-R. It becomes possible to save. As another embodiment of the DVD-R shown in FIG. 17, in the above document, one disk is replaced with a disk-shaped protection plate, and a recording layer, a reflection layer, and a protection layer are sequentially provided only on one substrate. There is also disclosure of an optical information recording medium having a configuration.

[0004]

The present inventors have studied the performance of an optical information recording medium in which two disc-shaped substrates are bonded together with an adhesive layer as described above. According to this, it was found that peeling was likely to occur at the ends of the two substrates, and that the storage stability (durability) was not sufficient. And it discovered that the problem of peeling arises for the following reasons.
That is, as one mode of an optical information recording medium formed by laminating two disc-shaped substrates, for example, as shown in FIG. 16, a recording layer 163 and a reflective layer 164 are provided in this order. A structure in which a disk-shaped substrate 161 provided with a protective layer 165 so as to cover the reflective layer 164 thereon and a disk-shaped protective plate 162 are joined via an adhesive layer 166 is conceivable. The optical information recording medium is generally manufactured by the following steps. First, the recording layer 163
Is formed on the disk-shaped substrate 161. The recording layer 163
Since it is usually formed by applying a coating liquid for a recording layer using a spin coater, it is applied over the entire surface of the disc-shaped resin substrate 161 as shown in the figure. Next, a reflective layer 164 made of metal is provided on the recording layer 163 by a method such as vapor deposition or sputtering so that the outer peripheral edge of the reflective layer is inside the outer peripheral edge of the recording layer. Next, the protective layer 16 is covered with the ultraviolet curable resin so as to cover the reflective layer 164.
After the substrate 5 is provided, the obtained substrate 161 and a protective plate (substrate) 162 having the same shape as the substrate are bonded with an adhesive (adhesive layer 166) with the recording layer 163 inside. Thus, the structure shown in FIG. 16 can be obtained. In a normal disk-shaped substrate, the region other than the region where the pre-groove exists, that is, the end surface and the end surface of the substrate (side surface of the outer periphery of the substrate) have very high precision surface properties. .

In general, in the above-mentioned sandwich type optical information recording medium, since the reflection layer is a layer made of metal, a sufficient bonding is made at the respective interfaces between the reflection layer and the recording layer and between the reflection layer and the protective layer. I cannot gain power. Therefore, the bonding strength between the two substrates is determined by the bonding at the respective interfaces between the layers in the region where the reflective layer is not interposed, that is, the outer region near the peripheral edge of the hole and the inner region near the outer peripheral edge of the substrate. Mainly held by force.
This also means that, for example, when the medium is deformed by impact or bending, the strain appears as peeling at the edge of the substrate, particularly at the outer edge. Therefore, it is desirable that the structure of the end portion sandwiched between the two substrates be designed more firmly. However, further studies by the present inventor show that
Conventionally, at the outer peripheral end of this type of substrate, FIG.
As shown in, the protective layer is not in direct contact with the substrate, is in a state of being bonded to the substrate via the recording layer, and since the recording layer itself is a layer made of a dye, there is sufficient interlayer It was found that no adhesive force could be obtained, and thus peeling was likely to occur at the interface between the substrate and the recording layer or between the recording layer and the protective layer. In the portion where the protective layer is in contact with the recording layer,
It has also been found that the adhesive strength decreases over time, the film easily peels off, and sufficient durability (storage stability) cannot be obtained. Although the reason is not clear, the portion of the recording layer where the protective layer is in contact is susceptible to components in the protective layer, for example, radical components, and the end surface (side surface) of the recording layer is exposed, This is presumably because the recording layer is easily affected by oxygen and the like, so that the recording layer deteriorates over time.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical information recording medium having a structure in which peeling does not easily occur by realizing high adhesiveness at outer end portions of two substrates. Another object of the present invention is to provide an optical information recording medium having good durability (storage stability).

[0007]

According to the research of the present inventors,
By performing surface processing on a region from the outer end surface to the side surface of the substrate having the recording layer, the surface area of the region is increased, and a recording layer (preferably a protective layer together with the recording layer) is bonded to this region. It has been found that higher adhesion can be realized at the edge of the substrate. In particular, in the present invention, when providing a recording layer and a reflective layer on the substrate,
These layers are not provided on the entire surface of the substrate up to the outer edge of the substrate, but the recording layer and the reflective layer are provided on the outer edge of the substrate except for the area where the substrate surface is exposed, and the side surface of the substrate is exposed from the exposed surface. By applying surface processing such as roughening to the area leading to the surface area, the surface area of the area is increased, and by bonding the protective layer to this surface processed area, a high adhesive force can be applied to the end of the substrate, It has been found that an optical information recording medium having a structure in which the edge of the substrate is hard to peel off can be obtained, and the present invention has been completed.

According to the present invention, there are provided two disk-shaped substrates having a hole at the center provided with a recording layer, a reflective layer and a protective layer in this order, or a recording layer, a reflective layer and a protective layer in this order. A sandwich-type optical information in which a disk-shaped substrate having a hole at the center provided and a disk-shaped protection plate having the same shape as the substrate are bonded via an adhesive layer such that the recording layer side is inside. In the recording medium, by performing surface processing on a region from the surface of the outer end portion of the substrate having the recording layer to the side surface of the substrate, the surface area of the region is increased,
An optical information recording medium characterized in that a recording layer is joined to the surface-treated area.

The present invention preferably has the following aspects. (1) By retreating both the outer end of the recording layer and the outer end of the reflective layer to the inside, the surface of the outer end of the substrate is exposed, and the surface from the exposed surface to the side surface of the substrate is subjected to surface processing. The surface area of the region is increased, and the protective layer is bonded to the surface-treated region. (2) Further, by retreating both the inner ends of the recording layer and the reflective layer inward, the substrate surface in the outer region near the periphery of the hole is exposed, and the exposed surface is subjected to surface processing. The surface area of the surface is increased, and a protective layer is bonded to the exposed surface subjected to the surface processing. (3) In the case of the above (1) or (2), the adhesive layer is bonded together with the protective layer to the surface-processed region or the exposed surface. (4) The surface processing is roughening or chamfering. (5) The recording layer is a dye recording layer. (6) The protective layer is a layer made of a UV curable resin. (7) The surface processing is performed using a method of processing a corresponding portion of a mold for molding a substrate.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical information recording medium of the present invention will be described with reference to the accompanying drawings. 1 to 4 are cross-sectional views schematically showing preferred examples of the optical information recording medium of the present invention. The optical information recording media 1 and 3 shown in FIGS. 1 and 3 respectively have recording layers 13 and 33, a reflective layer 14,
The disk-shaped substrates 11 and 31 having holes 10a and 30a at the center and having the same shape as the substrate (having holes 10b and 30b at the center) provided with the protective layers 15 and 35 in this order. This is an example of a sandwich type in which the disk-shaped protective plates 12 and 32 are bonded via adhesive layers 16 and 36 such that the recording layer side is on the inside. In the embodiment shown in FIG. 1, a region (a corner where both surfaces intersect) from the outer end surface of the substrate having the recording layer to the side surface thereof is chamfered, and the recording layer 13 is chamfered. Is bonded to the region 17 to which the. Further, in the embodiment shown in FIG. 3, a region (exposed surface) 38 exposing the end surface of the substrate is provided on the outer end surface of the substrate having the recording layer.
And a region from the exposed surface to the side surface of the substrate (a corner portion where both surfaces intersect) is chamfered. The end of the protective layer 35 is bonded to the chamfered region 37 in a tight contact state. In addition, it is preferable that the chamfering process is performed also in the outer end part inside the disk-shaped protection plate.

The optical information recording media 2 and 4 shown in FIGS. 2 and 4 have recording layers 23a, 23b and 43, respectively.
a, 43b, reflective layers 24a, 24b, 44a, 44b,
And holes 20a, 20b, 40a, 40b in the center where protective layers 25a, 25b, 45a, 45b are provided in this order.
Disk-shaped substrates 21a, 21b, 41a, 41 having
b so that the recording layer side is inside.
This is an example of a sandwich type that is pasted together via Nos. 6, 46. In the embodiment shown in FIG. 2, a region (a corner where both surfaces intersect) from the outer end surface of the substrate having the recording layer to the side surface of the substrate is chamfered, and the recording layers 23a and 23b are formed. Are joined to the chamfered regions 27a and 27b. Further, in the embodiment shown in FIG. 4, a region (exposed surface) 48 exposing the end surface of the substrate is provided on the outer end surface of the substrate having the recording layer.
a, 48b, and a region from the exposed surface to the side surface of the substrate (a corner portion where both surfaces intersect) is chamfered. The ends of the protective layers 45a and 45b are joined to the chamfered regions 47a and 47b in an intimate contact state.

In the embodiments shown in FIGS. 1 to 4, the layer configuration of the recording layer and the reflective layer at the inner end portion (outer region of the peripheral portion of the hole) of the substrate is arbitrary. As shown, in each of the embodiments, regions (exposed surfaces) 19, 29a, 29b, 39, 49a, and 49 where the substrate surface is exposed.
b, and the protective layers 15, 25a, 25b, 35, 45
a and 45b are connected to the exposed surfaces 19 and 29, respectively.
a, 29b, 39, 49a, and 49b are preferably bonded in close contact with each other. In addition, surface processing may be performed on an exposed region (exposed surface) of the substrate surface at the inner end.

The optical information recording medium of the present invention can be manufactured, for example, by the following method. The manufacturing method of the optical information recording medium of the present invention will be described in detail with reference to FIGS. FIG. 5 shows that a recording layer 13 is formed by applying a recording layer 13 on a disk-shaped substrate 11 having a hole 10a at the center and chamfering a corner formed between an outer end portion and an end surface (side surface) of the substrate surface. It is a fragmentary sectional view which shows the state provided. The chamfered substrate can be obtained by molding using a stamper or a mold (die) designed so that a predetermined corner portion is chamfered in advance. Alternatively, it can be obtained by performing mechanical processing after molding the substrate by a usual method. Usually, a substrate obtained by using the former method is advantageously used. By changing the design of the stamper or mold so as to have a predetermined shape, substrates of various shapes can be manufactured. At the time of chamfering, it is preferable to provide the processing area so as not to overlap the groove or the pit area of the substrate. For example, the chamfer is in the range of 1% to 50% (more preferably, 3% to 30%) of the thickness of the substrate in the thickness direction of the substrate, while the chamfer is in the diameter direction of the substrate. 0.05% to 3% of the diameter (more preferably 0.1 to 2%)
It is preferable to form in the range of.

The recording layer composed of a dye is formed on a disk-shaped substrate by using a coating solution for forming a recording layer, usually by spin coating. The recording layer 13 is formed so as to cover the chamfered area 17 on the outer edge of the substrate as shown in the figure. In addition, by using the spin coating method, the coating can be performed while controlling the coating position (the inner end of the recording layer) in the outer peripheral region of the central hole portion to some extent. Therefore, a region where the recording layer is not formed can be formed outside the peripheral portion of the central hole. However, in order to sufficiently secure the area where the recording layer is not formed, it is preferable to remove a certain area at the inner end of the recording layer after coating the recording layer. The application can be performed by using a method such as a roll coating method or a dip coating method other than the spin coating method, but it is more difficult to control the application region by using these methods as compared with the spin coating method. It is.

Next, a reflective layer made of metal is formed on the recording layer. FIG. 6 is a partial cross-sectional view schematically showing a state in which a reflective layer 14 is further formed on the recording layer 13 and both the outer ends of the recording layer and the reflective layer are retracted inward. As shown in FIG. 6, for providing the recording layer 13 and the reflective layer 14 on the substrate 11 in a predetermined range, for example, the following method can be used. 1) The outer edge of the recording layer (the area including the chamfered portion including the recording layer) is washed down to a predetermined position by a spin coating method using an appropriate solvent (spin cleaning), and the recording layer in that area is washed away. Remove. After that, a reflective layer is formed by masking. The reflective layer is deposited, sputtered,
Alternatively, it can be formed using a method such as ion plating. 2) After forming the reflective layer on the recording layer by masking in the same manner as described above, the recording layer at the portion protruding from the reflective layer (outer edge of the recording layer) is washed away by the spin cleaning described above.
The protruding portion of the recording layer is removed. 3) After the reflective layer is formed on the recording layer by masking in the same manner as described above, in the next step of applying a coating liquid for forming a protective layer, this coating liquid is applied by a spin coating method while simultaneously forming the outer edge. The recording layer is washed away, and the recording layer in that area is removed. By using this method, coating for forming the protective layer can be performed simultaneously with the removal of the recording layer at the outer end.

In order to remove the recording layer at the outer end, in addition to the spin cleaning as described above, a method of wiping off the recording layer after the coating and before drying the recording layer or a method of burning with a laser beam is used. May be. These methods can also be used in combination when a region where the recording layer is not formed is formed in the outer peripheral region of the central hole. In addition,
The method of forming the recording layer in a predetermined range by removing the recording layer at the outer end as described above is described in, for example,
These methods are described in JP-A-183442 and JP-A-2-236833, and these methods can be used.
According to the above-described method, both the outer end portions of the recording layer 13 and the reflective layer 14 can be receded inward, and the region (exposed surface) 18 in which the substrate end surface is exposed can be formed. Then, by forming the exposed surface, the exposed surface 18 is formed.
In the region from to the side surface of the substrate, a region 17 subjected to chamfering appears. The area where the chamfering process is performed from the area where the substrate end surface is exposed (the area of the width indicated by L)
Is a region where the protective layer is directly bonded to the substrate surface, and this region is 0.05 m along the outer edge of the entire circumference of the substrate.
Preferably, it is provided with a width in the range of m to 10 mm.
More preferably, this area is between 0.2 mm and 1.0 mm
Is preferably provided in a width in the range of In the case of FIG. 6, the area 1 chamfered from the outer edge of the recording layer
By 7, there is an exposed surface 18 of the substrate, but chamfering may be performed so as to be in contact with the outer end of the recording layer. In the region where the surface of the substrate is exposed (exposed surface), the dye is not completely removed, and there are some portions that remain. However, there is almost no problem in bonding the protective layer.

Next, a protective layer is formed on the recording layer and the reflective layer. FIG. 7 is a partial cross-sectional view schematically showing a state in which the protective layer 15 is provided so that the edge of the protective layer is in contact with a region from the recording layer 13 and the reflective layer 14 to the chamfered region 17. It is. The protective layer is formed by applying a resin such as a thermoplastic resin, a thermosetting resin, or a UV (ultraviolet) curable resin from the reflective layer to the chamfered region, as described later. However, it is preferable to use a UV (ultraviolet) curable resin in terms of productivity, strength of the obtained medium, and the like. UV
When a curable resin is used, a protective layer can be formed by applying the resin liquid by using a spin coating method or the like and then irradiating UV light. At the inner end of the substrate, as shown in the figure, the protective layer 15 is arranged such that the end thereof comes into contact with a region (exposed surface) 19 where the recording layer is not formed in the outer peripheral region of the central hole. Preferably, it is provided.

As shown in FIGS. 5 to 7, the recording layer 13,
The substrate 11 on which the reflective layer 14 and the protective layer 15 are provided in this order is then superimposed on a separately prepared disk-shaped protective plate (substrate) 12 having the same shape as this substrate, with the recording layer inside,
Laminate with adhesive. Two substrates are bonded together on one or both substrates (or on the protective layer)
After applying an adhesive, the bonding surfaces of the substrates are overlapped with each other, and for example, a pressing plate 81 of a pressing device 80 shown in FIG.
a, 81b, and pressurizing. The adhesive can be used by appropriately selecting an adhesive such as a thermoplastic resin, a thermosetting resin, or a UV (ultraviolet) curable resin. However, when producing an optical information recording medium as shown in FIGS. 2 and 4, it is difficult to use a UV-curable resin adhesive because the recording layers are provided on both substrates. Therefore, in the case of the type shown in FIGS. 2 and 4, a material other than the UV curable resin adhesive is used. When a UV-curable resin is used, a transparent material is used for the pressing plate because UV light is irradiated while performing a pressing process. For example, white plate glass, quartz glass,
Blue plate glass can be mentioned as a preferable thing.
The adhesive layer is usually formed so that its end surface (side surface) is substantially the same as the end surface (side surface) of both substrates (the same surface) or slightly inside, but the side surface shape is somewhat concave. There is no particular problem whether it is present or convex.

In the optical information recording medium of the present invention, by adjusting the masking position, for example, as shown in FIG. 9A, a reflective layer 14 having a shape covering the entire recording layer 13 may be formed. it can. Further, as shown in FIG. 9B, the recording layer 13 has a two-layer structure (a recording layer 13A,
13B). Further, as shown in FIG. 9C, the recording layer 13 has a two-layer structure (recording layers 13A and 13B) with an intermediate layer 50 interposed therebetween, and each of the layers located above is the same as the layer located below. It can also be configured to cover. These optical information recording media can also be manufactured by utilizing the manufacturing method described above.

In the optical information recording medium of the present invention, another example of the shape of the surface-processed substrate (the region from the outer end surface to the side surface of the substrate) will be described below. 10 to 14
3 is a partial cross-sectional view schematically showing an example in which various shapes of surface processing are applied to regions from the outer end surface of the substrate to the side surface of the substrate in the optical information recording medium of the embodiment shown in FIG. 3. is there. In FIGS. 10 to 14, the area on which the surface processing has been performed is indicated by 17. As shown in FIG. 10 (a), the surface is processed so as to form a round shape at a corner where an outer end portion (exposed surface) of the substrate and a side surface of the substrate intersect. As shown in FIGS. 10B to 10D,
The surface processing performed on the recording layer side may be similarly performed symmetrically on the opposite side of the substrate (the side on which the recording layer is not provided). As described above, by performing chamfering on the side of the substrate on which the recording layer is not provided, it is possible to suppress the occurrence of burrs that tend to occur at corners of the substrate when the substrate is manufactured.

As shown in FIG. 11, the substrate may be roughened. As the rough surface processing, FIG.
As shown in (b), it can be performed on one substrate and the other substrate (protective plate) with different rough surfaces. The protective layer is provided so as to be bonded to the roughened region. However, as shown in FIG. 11D, when the end surface (side surface) of the substrate is roughened, the protective layer becomes It is preferable to be provided so as to be bonded also to this surface. Further, as shown in FIG. 11 (e), it is also possible to chamfer a corner portion of the substrate in advance and further roughen this region. By combining such surface processing, the adhesive strength at the end of the substrate can be further increased. The rough surface processing is preferably performed so that the average roughness is in a range of 0.01 μm to 1 mm (more preferably, in a range of 0.1 μm to 100 μm).

FIG. 12 shows an example in which a region from the outer end surface of the substrate to the side surface of the substrate is surface-processed with a projection or a notch, and the shape and size of the projection and the notch are appropriately set. be able to. In addition, as described in FIG. 11, when the protrusion is formed on the end surface (side surface) of the substrate (FIGS. 12E and 12F), the protective layer is also bonded to this surface. It is preferable to be provided as follows.

FIGS. 13 (a), 13 (b) and 13 (d) show the shape of the surface of the outer end portion of the substrate as having a gentle inclination toward the end portion, a gentle concave shape, or a gentle convex shape. It shows an example of surface processing. Such a shape can also increase the surface area of the substrate. Further, as shown in FIG. 13C, the surface can be processed so that the cross-sectional shape of the side surface of the substrate is obtuse with respect to the outer end surface of the substrate. As shown in FIG. 14, a zigzag may be radially formed along the outer edge of the outer peripheral edge of the substrate as the surface processing. In the present invention, the substrate is formed by chamfering shown in FIG.
It is preferable that the rough surface processing shown in 1 is performed. In addition,
As described above, the shape of the substrate described above can be made a desired shape by changing the design at the stage of molding the substrate. Further, the rough surface processing can be performed by, for example, using a method of treating the surface of the substrate with a solvent, a method of filing using a file or the like to roughen the surface, or a method of sandblasting after molding the substrate.

As shown in FIG. 15, the optical information recording medium of the present invention is provided so as to be in contact with only a part of the outer edge of the substrate in the region 17 on which the surface of the protective layer 15 has been processed, and to cover the remaining region. Can be configured so that the adhesive layer 16 contacts. The formation of the surface-processed region 17 in contact with the adhesive layer 16 is performed by applying the protective layer, dissolving the necessary region of the protective layer by a method such as spin cleaning described above, and starting from the surface-processed region. It can be done by washing away.

The above description of the method for manufacturing an optical information recording medium is for the example of the sandwich type shown in FIG. 3, but a hole is formed at the center where a recording layer, a reflective layer and a protective layer are provided in this order. In the case of a sandwich type (FIG. 4) in which two disk-shaped substrates each having a portion are bonded via an adhesive layer such that the recording layer side is on the inside, the same manufacturing can be performed. In addition, as shown in FIG. 1 or 2, an optical information recording medium in which a recording layer is bonded to a surface-processed region can be similarly manufactured. In this case, when the surface-processed region, particularly the surface-processed region extends to the side surface of the substrate, it is preferable to bond the protective layer together with the recording layer.
When manufacturing these optical information recording media, FIG.
As described in the above, the recording layer may have a two-layer structure with an intermediate layer interposed, or the reflective layer may be provided so as to cover the entire recording layer. Furthermore,
Substrates having various shapes described with reference to FIGS. 10 to 14 can be used. (When used for the optical information recording medium shown in FIG. 1 or 2, recording is performed on the surface-processed region. The layers are joined).

In the production of the optical information recording medium of the present invention, materials conventionally used for optical information recording media can be selected and used. Hereinafter, these materials will be briefly described. As a disc-shaped substrate material, for example,
Acrylic resin; polyvinyl chloride, polyvinyl chloride resin such as copolymer of vinyl chloride and another polymer; epoxy resin; polycarbonate resin; amorphous polyolefin and polyester. Preferred are polycarbonates, polyolefins and cell cast polymethyl methacrylate. The thickness of the disc-shaped substrate is 0.1% to 3.0% of the diameter of the substrate (preferably,
(0.2% to 2.5%).

An undercoat layer may be provided on the surface of the substrate on which the recording layer is provided, for the purpose of improving flatness, improving adhesiveness, improving the form of the substrate, and preventing deterioration of the recording layer. Materials for forming the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol,
N-methylol acrylamide, styrene / vinyl toluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin,
High-molecular substances such as polyester, polyimide, vinyl acetate, vinyl chloride copolymer, ethylene, polypropylene, and polycarbonate, and inorganic oxides (SiO ₂ , Al ₂ O
₃ ) and inorganic substances such as inorganic fluorides (MgF ₂ ). The undercoat layer is formed by using a known method (a coating method such as spin coating, dip coating, or extrusion coating, or a vacuum film forming method such as evaporation, sputtering, or ion plating) using the above materials. be able to.

On the substrate (or undercoat layer), a pre-group layer and / or a pre-pit layer may be formed in order to form irregularities indicating information such as tracking grooves or address signals. As a material for forming the pregroup, a mixture of at least one monomer (or oligomer) of acrylic acid monoester, diester, triester, and tetraester and a photopolymerization initiator can be used. The pre-group layer can be formed by a conventional method.

The recording layer is preferably constituted by a layer composed of a dye. The dye used is not particularly limited. For example, cyanine dyes, phthalocyanine dyes,
Imidazoquinoxaline dyes, pyrylium / thiopyrylium dyes, azulenium dyes, squalilium dyes, metal complex dyes such as Ni and Cr, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenyl Examples include methane dyes, triallylmethane dyes, merocyanine dyes, oxonol dyes, aluminum / diimmonium dyes, and nitroso compounds. Among these dyes, cyanine dyes, phthalocyanine dyes, azulhenium dyes, squalilium dyes, oxonol dyes, and imidazoquinoxaline dyes are preferred. The recording layer can be formed by dissolving the dye and, if necessary, the binder in a solvent to prepare a coating solution, applying the coating solution on a substrate by the method described above, and drying. The recording layer generally has a thickness of 10 to 550 nm.
Is provided so as to have a thickness in the range. As shown in FIGS. 9B and 9C, the intermediate layer can be formed using the material used for forming the undercoat layer. The intermediate layer is generally provided in a range of 1 to 100 μm.

The light-reflective substance used as the material of the reflection layer is a substance having a high reflectance with respect to laser light. Specifically, the reflection layer is preferably a layer made of a metal and a metalloid. Examples of these include Mg, Se, Y, Ti, H
f, V, Nb, Ta, Cr, Mo, W, Mn, Re, F
e, Co, Ni, Ru, Rh, Pd, Ir, Pt, C
u, Ag, Au, Zn, Cd, Al, Ga, In, S
i, Ge, Te, Pb, Po, Sn and Bi. Of these, Au, Ag, C
u, Pt, Al, Cr and Ni,
In particular, Au is preferable. These may be used alone or in combination of two or more. The reflective layer is generally provided to have a thickness in the range of 10 to 300 nm.

The material (adhesive) used for forming the protective layer or the adhesive layer may be a thermoplastic resin, a thermosetting resin, a UV (ultraviolet) curable resin, or an adhesive made of these resins. Can be mentioned. In forming the protective layer, it is particularly preferable to use a UV curable resin. Examples of UV-curable resins include oligomers of (meth) acrylates such as urethane (meth) acrylate, epoxy (meth) acrylate, and polyester (meth) acrylate, and monomers such as S (meth) acrylate. Usually, a UV curable resin such as a polymerization initiator can be used. The protective layer is generally 0.1 to 100.
It is provided so as to have a thickness in the range of nm, preferably in the range of 1 to 15 nm. The adhesive layer has an average thickness of generally 0.1 μm to 100 μm, preferably 20 μm to 80 μm, and more preferably 30 μm to 7 μm.
It is provided so as to be in a range of 0 μm.

[0032]

EXAMPLES Examples and comparative examples of the present invention will be described below. [Example 1] A dye represented by the following structural formula

[0033]

Embedded image

Is dissolved in 2,2,3,3-tetrafluoropropanol and a coating solution for forming a dye recording layer (dye 2.65)
% By weight). A tracking guide is provided,
Disc-shaped polycarbonate substrate with chamfered outer edge (outer diameter: 120 mm, thickness: 0.6 mm, inner diameter 15 mm, groove width: 0.4 μm, depth: 200 n
m, shape of chamfer: 0.2 mm in thickness direction x 0 in diameter direction.
5 mm) was applied by spin coating at a rotation speed of 1000 rpm. Subsequently, a certain area outside the vicinity of the periphery of the hole was wiped off, and the inner end of the recording layer was receded outward to form an exposed area of the substrate surface (exposed surface of the inner end). Then, the coating layer is
After drying at a temperature of 10 ° C. for 10 minutes, a recording layer having a thickness of 120 nm was formed (see FIG. 5). Au was vapor-deposited on the dye recording layer using a mask to form a reflective layer having a thickness of 100 nm. By this operation, the reflective layer was provided so that the outer peripheral edge was located inside the outer peripheral edge of the recording layer. On the surface of the substrate provided with the reflective layer, 2, 2, 3,
The solvent of 3-tetrafluoropropanol was sprayed by a spin coating method to remove the recording layer applied to the area other than the area where the reflective layer was provided. As a result, a region where the substrate surface was exposed (exposed surface at the outer end) was formed at the outer end of the substrate. This exposed surface was formed with a width of 0.7 mm along the outer peripheral edge of the substrate (see FIG. 6). The chamfered region appeared on the substrate due to the removal of the recording layer. On the reflective layer, a UV curable resin liquid (trade name:
3070 (manufactured by Three Bond Co., Ltd.) was applied at a rotation speed of 1500 rpm by a spin coating method. The coating layer was cured by irradiating ultraviolet rays from a high-pressure mercury lamp with a high-pressure mercury lamp to form a protective layer so that the layer thickness was 5 μm (FIG. 7).
reference). Next, a UV curable adhesive (trade name: 3070, manufactured by Three Bond Co., Ltd.) was applied on the protective layer at a rotation speed of 1500 rpm by a spin coating method. Then, a substrate coated with the adhesive and a separately prepared disc-shaped polycarbonate substrate (protective plate) (outer diameter: 120 mm, thickness: 0.6 mm, chamfered to the outer end portion in the same manner as the above substrate) Are placed on top of each other with the surface on which the adhesive is applied facing inward. Then, in a pressurized state (0.2 kg / cm ² ), ultraviolet rays are irradiated from a pressure plate in contact with the protection plate with a high-pressure mercury lamp to cure the pressure plate, thereby forming an adhesive layer having a layer thickness of 8 μm. did. Thus, an optical information recording medium having the structure shown in FIG. 3 was manufactured.

Example 2 In Example 1, a disc-shaped polycarbonate substrate having a roughened outer end portion (outer diameter: 120 mm, thickness: 0.6 mm, inner diameter 15 mm, grooved Width: 0.4 μm, depth: 200
nm, average roughness of rough surface: 1 μm) and a disc-shaped polycarbonate substrate (protective plate) with a roughened outer edge
(Outer diameter: 120 mm, thickness: 0.6 mm, average roughness of the rough surface: 1 μm)), except that the optical information recording medium was manufactured in the same manner as in Example 1. Thus, FIG.
An optical information recording medium having the structure shown in FIG.

[Comparative Example 1] In Example 1, as a disc-shaped polycarbonate substrate, a substrate whose outer end portion was not chamfered (outer diameter: 120 mm, thickness: 0.6)
mm, inner diameter 15 mm, groove width: 0.4 μm, depth: 200 nm), and a substrate whose outer end is not chamfered as a protective plate. An optical information recording medium was manufactured in the same manner as in Example 1, except that the recording layer applied to the area other than the area where the layer was provided was not removed.
Thus, an optical information recording medium having the structure shown in FIG. 16 was manufactured.

[Evaluation as Optical Information Recording Medium] With respect to the optical information recording medium obtained as described above, (1) drop test and (2) C / N of the outer edge of the substrate were measured. Each was evaluated. (1) Drop test Drops were dropped onto a concrete floor 20 times from a height of 1 m, and peeling of the outer end of the substrate was observed. The evaluation criteria are as follows. A: Almost no peeling of the outer edge of the substrate was observed. B: Peeling of the outer edge of the substrate was slightly observed. C: Peeling of the outer edge of the substrate was considerably observed. (2) C / of the outer edge of the substrate (the outermost peripheral portion of the groove)
Measurement of N Using DDU1000 (manufactured by Pulstec), 1.2 m
After recording at 11 T / sec, the data was reproduced and measured with a spectrum analyzer TR4135 (manufactured by Advantest Corporation). After the production, 24 hours at 80 ° C. and 85% RH.
The medium obtained after storage for 0 hours was subjected to a drop test and a measurement of C / N at the outer edge of the substrate in the same manner as described above, and evaluated according to the same criteria. Table 1 shows the results.

[0038]

[Table 1] Table 1 落下 Drop test after storage after storage End C / N Drop Test End C / N 実 施 Example 1 A 56 dB A 53 dB Example 2 A 56 dB A 53 dB Comparative Example 1 C 53 dB C 49 dB ─────────────────────────────── ─────

From the results in Table 1 above, this surface processing was performed using a substrate whose outer end was subjected to surface processing (chamfering processing (Example 1), rough surface processing (Example 2)). In the optical information recording medium according to the present invention (Examples 1 and 2) in which a protective layer is directly bonded to a region which has been provided, a substrate whose outer end is not subjected to surface processing is used, and the protective layer is Compared to a comparative optical information recording medium (Comparative Example 1) provided so as to be joined to the substrate end via the recording layer, the outer end of the substrate hardly peeled off, and the value of the high end C / N was high. It can be seen that can be obtained. Further, the optical information recording medium according to the present invention also has a higher performance after storing these optical information recording media for a long time (particularly, storage under high temperature and high humidity) as compared with the optical information recording medium of the comparative example. There is almost no peeling of the substrate edge, and similarly, a high edge C / N value is maintained. Therefore, it can be said that the optical information recording medium according to the present invention also has high storage stability.

[0040]

According to the optical information recording medium of the present invention, the surface is processed in the region from the outer end to the side surface of the substrate, thereby increasing the surface area of the region. The bonding strength with the recording layer can be increased. In particular, by retreating the outer end of the reflective layer and the recording layer on the substrate, the surface of the outer end of the substrate is exposed, and a surface processing is performed on a region from the exposed surface to the side surface of the substrate,
In the aspect in which the protective layer is provided so as to be directly bonded to the surface-treated area, a high adhesive force can be applied to the outer end of the substrate, and therefore, peeling at the end of the substrate hardly occurs. Further, in this embodiment, since the recording layer and the reflection layer are completely covered with the protective layer, the recording layer and the reflection layer are directly shielded from the outside air, and high storage stability can be secured. Therefore, high durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a preferred example of an optical information recording medium of the present invention.

FIG. 2 is a sectional view schematically showing another preferred example of the optical information recording medium of the present invention.

FIG. 3 is a sectional view schematically showing another preferred example of the optical information recording medium of the present invention.

FIG. 4 is a sectional view schematically showing another preferred example of the optical information recording medium of the present invention.

FIG. 5 is a partial cross-sectional view schematically showing a state in which a recording layer is provided by coating on a disk-shaped resin substrate having a hole at the center and a chamfered outer edge of the substrate. is there.

FIG. 6 is a diagram showing a state in which a reflective layer is further formed on the recording layer, and both the outer end of the recording layer and the outer end of the reflective layer are receded inward; It is a fragmentary sectional view showing typically the state where the chamfering performed appears.

FIG. 7 is a partial cross-sectional view schematically showing a state in which a protective layer is provided from above the recording layer and the reflective layer to a region where chamfering has been performed.

FIG. 8 is a diagram schematically showing a state in which two substrates are sandwiched between pressure plates of a pressure bonding apparatus and pressure processing is performed.

FIG. 9A is a partial cross-sectional view schematically showing an optical information recording medium having a reflective layer having a shape covering the entire recording layer. FIG. 9B is a partial cross-sectional view schematically showing an optical information recording medium when the recording layer has a two-layer structure with an intermediate layer interposed. FIG. 9C is a partial cross-sectional view schematically showing an optical information recording medium in which a recording layer is formed as a reflective layer covering the entire surface, and the recording layer has a two-layer structure with an intermediate layer interposed therebetween. .

FIG. 10 is a partial cross-sectional view schematically showing another example in which various types of surface processing (chamfering) are performed on a region from the outer end surface to the side surface of the substrate.

FIG. 11 is a partial cross-sectional view schematically showing another example in which various shapes of surface processing (rough surface processing) are performed on a region from the outer end surface to the side surface of the substrate.

FIG. 12 is a partial cross-sectional view schematically showing another example in which various shapes of surface processing are performed on a region from the outer end surface to the side surface of the substrate.

FIG. 13 is a partial cross-sectional view schematically showing another example in which various shapes of surface processing are applied to a region from the outer end surface to the side surface of the substrate.

FIG. 14 is a diagram schematically showing an example in which an optical information recording medium is provided with a surface processing in a zigzag shape along the outer peripheral edge along the outer peripheral edge in a region from the outer peripheral surface to the side surface of the substrate. It is. FIG. 14A is a plan view thereof,
(B) is the figure seen from the side.

FIG. 15 is a partial cross-sectional view schematically showing a state in which a protective layer and an adhesive layer are provided so as to be in contact with a surface-processed region.

FIG. 16 is a partial cross-sectional view schematically showing a conventional optical information recording medium in which a recording layer is provided up to a tip of an outer end of a substrate.

FIG. 17 is a partial cross-sectional view schematically illustrating a basic structure of a conventionally proposed optical information recording medium (DVD-R).

[Explanation of symbols]

1, 2, 3, 4 Optical information recording media 10a, 10b, 20a, 20b, 30a, 30b, 4
0a, 40b Holes 11, 21a, 21b, 31, 41a, 41b, 16
1, 171a Disc-shaped substrate 12, 32, 162 Disc-shaped protective plate 13, 13A, 13B, 23a, 23b, 33, 43
a, 43b, 163, 173a Recording layer 14, 24a, 24b, 34, 44a, 44b, 16
4, 174a Reflective layer 15, 25a, 25b, 35, 45a, 45b, 16
5, 175a Protective layer 16, 26, 36, 46, 166, 176 Adhesive layer 17, 27a, 27b, 37, 47a, 47b Surface-treated regions 18, 19, 29a, 29b, 38, 39, 48a , 4
8b, 49a, 49b Exposed surface 50 Intermediate layer 80 Crimping device 81a, 81b Pressing plate

Claims (7)

[Claims] 1. A disk-shaped substrate having a hole at the center where a recording layer, a reflective layer and a protective layer are provided in this order, or a recording layer, a reflective layer and a protective layer are provided in this order. Sandwich-type optical information recording medium in which a disc-shaped substrate having a hole in the center and a disc-shaped protective plate having the same shape as the substrate are bonded via an adhesive layer such that the recording layer side is inside. In the above, by performing surface processing on a region from the surface of the outer end portion of the substrate having the recording layer to the side surface of the substrate, the surface area of the region is increased, and the recording layer is bonded to the region on which the surface processing has been performed. An optical information recording medium, characterized by being made to work. 2. The method according to claim 1, wherein both the outer edge of the recording layer and the outer edge of the reflective layer are retracted inward, thereby exposing the outer edge surface of the substrate and performing surface processing on a region extending from the exposed surface to the side surface of the substrate. 2. The optical information recording medium according to claim 1, wherein the surface area of the region is increased, and a protective layer is bonded to the surface-treated region. 3. The substrate surface in the outer region near the peripheral edge of the hole is exposed by retreating both the inner end of the recording layer and the inner end of the reflective layer inward, and the exposed surface is subjected to surface processing. The optical information recording medium according to claim 1, wherein the surface area of the surface is increased, and a protective layer is bonded to the exposed surface subjected to the surface processing. 4. The optical information recording medium according to claim 2, wherein an adhesive layer is bonded to the surface-processed region or the exposed surface together with the protective layer. 5. The optical information recording medium according to claim 1, wherein the surface processing is roughening or chamfering. 6. The optical information recording medium according to claim 1, wherein the recording layer is a dye recording layer. 7. The optical information recording medium according to claim 1, wherein the protective layer is a layer made of a UV curable resin.