JPH09115191A - Optical information recording medium and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical disk of a multilayered structure having excellent accuracy and productivity. SOLUTION: A substrate 4 and a stamper 21 are superposed on each other interposing a radiation-curing resin 22 between them and, thereafter, the substrate 4 and the stamper 21 are rotated at a high speed. This radiation-curing resin 22 applied on the central part is spread to the outer peripheral part by the centrifugal force of rotation and, further, the excess radiation-curing resin 22 is shaken off toward the outer side and is removed from the end face of the substrate 4 and the stamper 21. Then, a transparent resin layer which has a uniform film thickness and does not contain air bubbles is formed by a uniform outward force in the horizontal direction by the centrifugal force of a high-speed rotation with a short time production process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium and a method for manufacturing the same, and in particular, it has a radiation curable resin layer on a substrate made of a light transmissive material, and the radiation curable resin layer has an uneven shape. The present invention relates to an optical information recording medium having an information recording surface by forming a film and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, there is an optical information recording medium in which optically readable information is recorded, and the recorded information is read out by using a laser beam spot. Optical discs such as CD-ROMs) and CD-ROMs have been remarkably spread. The above CD-ROM is
Not only for computer but recently for multi-function game CD
-ROM has also been introduced, and it can be used for magnetic disks (floppy disks) and ROM cartridges for computers and games.
The transfer to D is progressing.

Further, a high-density optical disc in which information is recorded at a high density by recording pits smaller than a CD with a track pitch narrowed has been proposed, and it is whispered not only to movies but also to multimedia. . Furthermore, the above C
While D has a single-layer information recording surface on which a signal is recorded only on one surface of the substrate, the thickness of the substrate can be increased by stacking a transparent resin layer made of a radiation curable resin on the substrate. A multi-layered optical disc having a plurality of information recording surfaces in the direction has been proposed.

The optical disc having the above-mentioned multilayer structure will be described below with reference to FIG. FIG. 1 is a diagram showing a structure of an optical disc having a multilayer structure. The figure shows a part of a sectional view of the optical disc in the track direction. Further, for the sake of simplicity, the optical disc having a multilayer structure described below will be described as one having two information recording surfaces.

As shown in FIG. 1, a conventional multi-layered optical disc (hereinafter, simply referred to as an optical disc) 1 has a first reflective layer 5, a transparent resin layer 6 and a second transparent layer 4 on a light transmissive substrate 4.
The reflective layer 7 and the protective film 8 are laminated in this order. An uneven pit 4A corresponding to information is formed on the substrate 4, and an uneven pit 4B corresponding to information is formed on the transparent resin layer 6. That is, the optical disc 1 has two information recording layers in the thickness direction of the substrate 4, and the pit 4A forming surface of the light transmissive substrate 4 is the first information recording surface 2 and the transparent The surface of the resin layer 6 on which the pits 4B are formed is the second information recording surface 3.

Further, the first reflective layer 5 formed between the first information recording surface 2 and the second information recording surface 3 prevents the incidence and reflection of light on the second information recording surface 3. It is made of a material having a certain degree of light transmittance so that it can be performed. Hereinafter, the first reflective layer 5 will be referred to as a semitransparent reflective layer 5, and the second reflective layer 7 will be referred to as a reflective layer 7. Then, when forming three or more information recording surfaces, a second transparent resin layer is formed on the reflective layer 7 on the transparent resin layer 6, and pits are formed on the second transparent resin layer. Then, the third information recording surface is formed, and the fourth information recording surface and the subsequent layers are similarly configured.

Reproducing laser light for reading the information recorded on each information recording surface is incident from the lower side of the substrate 4. Here, although the distance between the information recording surfaces of the optical disc 1 is as narrow as several tens of microns, the optical pickup of the reproducing apparatus correctly recognizes the distance and focuses on the desired information recording surface to record each information. The surface information is read out. As described above, by providing the information recording surface of two or more surfaces in the thickness direction of the substrate 4 to form a multilayer structure, it is possible to record a larger amount of information than the conventional single-layer structure optical disk. It becomes.

Next, a conventional manufacturing method of the optical disc 1 having the above-mentioned structure will be described with reference to FIG. In addition, in order to simplify the description, a two-layer disc will be described. First, as shown in FIG. 3A, the pit 4A on the first information recording surface
The optical disk substrate 4 having the pits 4A on its surface is formed by, for example, injection molding using a stamper (not shown) having a reverse pattern of. Next, as shown in FIG. 3B, a semitransparent reflective layer 5 is formed on the surface of the substrate 4 on which the pits 4A are formed by sputtering, ion plating, and CV.
It is formed by a film forming method such as D, a vacuum vapor deposition method, or spin coating. The semitransparent reflective layer 5 is a reflective layer having a certain degree of light transmittance as described above.

Next, the second transparent layer 5 is formed on the semitransparent reflective layer 5.
The information recording surface 3 is formed. The second information recording surface 3 is formed by the conventionally known 2P method. That is, the same figure (C)
As shown in FIG. 3, a stamper 21 having a concavo-convex shape 21A having an inverse pattern of the pits 4B on the second information recording surface 3 is prepared, and the ultraviolet curable resin 2 is formed on the semitransparent reflection layer 5 of the substrate 4.
2 is dropped, and then the signal surface of the stamper 21 is pressed onto the substrate 4 onto which the ultraviolet curable resin 22 has been dropped to spread the ultraviolet curable resin 22 to a uniform thickness. When the stamper 21 is pressed, the resin overflowing from the outer peripheral portion of the substrate 4 is sucked by the nozzle 23 as shown in FIG. And
As shown in FIG. 6E, when ultraviolet rays (radiation) is irradiated from the substrate 4 side to cure the ultraviolet curable resin 22 and the stamper 21 is peeled off, as shown in FIG.
As a result, an optical disk substrate having pits 4B which will become the information recording surface 3 is obtained. Finally, a reflective layer 7 is formed on the second information recording surface 3 by vacuum deposition such as sputtering or vacuum vapor deposition of aluminum or gold, and the protective film 8 is further formed on the reflective layer 7. And a label (not shown) is printed on the protective film 8 to complete an optical disc having a multilayer structure as shown in FIG.

[0010]

By the way, in the above-mentioned optical disc having a multi-layered structure, it is necessary to control the distance between the respective information recording surfaces very strictly due to the restriction on the reproducing principle.
For example, with respect to the film thickness of the transparent resin layer of 40 μm, only a film thickness variation of about ± 3 μm is allowed. However, in the above-mentioned 2P method, even if the accuracy of the device is improved, the limit is about ± 5 μm. Further, the above-mentioned 2P construction method is poor in productivity, and it takes about 2 minutes per surface to mold the information recording surface after the second information recording surface. It is possible to increase the molding speed by increasing the pressing force or increasing the resin dropping amount, but the accuracy of the film thickness decreases, air bubbles are trapped and defects occur, and overflow is insufficiently absorbed. Problems such as occur. That is, if an attempt is made to manufacture an optical disc having a multilayer structure as described above by using a conventionally known manufacturing method, there arises a trade-off between accuracy and productivity.

In the case of the above manufacturing method, a silicon oxide film (SiOx) is used as the material of the semitransparent reflective layer 5.
Silicon oxide film-based alloy, silicon nitride film (SiNx),
It is common to use a silicon nitride film-based alloy, etc.
These materials have poor adhesion to the transparent resin layer 6 made of an ultraviolet curable resin, and there is a problem that they may crack during an environmental load test or may be peeled off if they are extremely heavy. It is easy to introduce a special functional group in order to give the resin adhesive strength, but if the semi-transparent reflective layer 5 is designed to have adhesive strength, a stamper (material nickel) is used.
However, there is a new defect that the adhesive force is generated and peeling becomes difficult. Further, an ideal resin that adheres to the semitransparent reflective layer 5 and does not adhere to nickel is very difficult to design, and does not actually exist.

Therefore, the present invention has been made in view of the above points, and an object thereof is to provide an optical disc having a multilayer structure excellent in accuracy, productivity and reliability, and a manufacturing method thereof. is there.

[0013]

Means for Solving the Problems As a means for achieving the above-mentioned object, the present invention provides a method in which a radiation-curable resin layer is laminated on a substrate made of a light-transmissive material, and the radiation-curable resin layer is formed on the substrate. In a method of manufacturing an optical information recording medium which is used as an information recording surface for recording information by forming an uneven shape by a guide groove or a pit, a surface of a stamper for forming the uneven shape of the radiation curable resin layer or the above A step of dropping a radiation curable resin on a substrate, a step of overlapping the substrate and the stamper so as to sandwich the dropped radiation curable resin, and a high-speed rotation in a state where the substrate and the stamper are superposed on each other. And a step of irradiating with radiation to cure the radiation-curable resin in this order.
It is intended to provide.

As a means for achieving the above-mentioned object, the present invention comprises "a semitransparent reflective layer and a radiation-curable resin layer are sequentially laminated on a substrate made of a light-transmissive material. In an optical information recording medium having an uneven shape formed by guide grooves or pits as an information recording surface for recording information, a primer film is formed between the semitransparent reflective layer and the radiation curable resin layer. An optical information recording medium characterized by the above.

[0015]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings. In the following description, the case of manufacturing the multi-layered optical disc 1 having the two information recording surfaces shown in FIG. 1 will be described. FIG.
FIG. 4 is a diagram for explaining the first embodiment of the method for manufacturing an optical information recording medium of the present invention. Disk substrate 4 having pits 4A engraved on its surface by a molding method such as injection molding
Of the substrate 4, a semitransparent reflective layer 5 is formed on the surface of the substrate 4 on which pits are formed by sputtering, vacuum deposition, ion plating, CVD, spin coating, or the like (a substrate made of a light transmissive material). Up to the step of applying a radiation curable resin to the surface of the semitransparent reflective layer 5 or the stamper 21, or both surfaces, and superposing the stamper 21 and the semitransparent reflective layer 5 (FIG. (A)). This is the same as the conventional method for manufacturing an optical disc having a multilayer structure, but in the present embodiment, the following steps are different.

That is, as shown in FIG. 1B, after the substrate 4 and the stamper 21 are overlapped with each other with the radiation curable resin 22 sandwiched therebetween, the substrate 4 and the stamper 21 are centered by a chain line in the figure. Rotate horizontally at high speed. Then
As shown in the figure, the radiation curable resin 22 applied to the central portion spreads to the outer peripheral portion due to the centrifugal force of rotation, and as shown in FIG.
Then, the stamper 21 is shaken off from the end face to the outside and removed. That is, conventionally, the film thickness of the transparent resin layer 6 was controlled by the pressing force and the pressing time of the stamper 21, and the surplus radiation curable resin 22 at the time of pressing was sucked by the nozzle, but in this embodiment, The film thickness of the transparent resin layer 6 is uniformly controlled by the centrifugal force generated by the high speed rotation, and the excess radiation curable resin 2
2 is removed.

Then, after removing the surplus radiation-curable resin 22, the rotation of the substrate 4 and the stamper 21 which are superposed on each other is reduced or stopped, and radiation is irradiated from the substrate 4 side as shown in FIG. After the radiation curable resin 22 is cured, the stamper 21 is peeled off to form the transparent resin layer 6 having the pits 4B formed on the surface thereof ((E) in the same figure). Then, finally, the reflection layer 7 and the protective film 8 are sequentially formed to manufacture a two-layer disc as shown in FIG.

As described above, the conventional method presses the stamper 21 perpendicularly to the substrate surface, but in the present embodiment, both the substrate 4 and the stamper 21 are rotated at high speed about their centers. Here, the film thickness of the transparent resin layer 6 depends on the pressure for pressing the stamper 21 by the conventional method, the pressing time,
While it largely depends on the resin viscosity, in the present embodiment, it largely depends on the rotational speed of the high speed rotation and the resin viscosity. That is,
In this embodiment, since the pressure and the pressing time for pressing the stamper 21 and the substrate are almost zero, there is no factor of film thickness variation due to pressure unevenness and pressing time error. Further, in the method according to the present embodiment, the uniform outward force in the horizontal direction due to the centrifugal force reduces the film thickness of the radiation curable resin 22 uniformly, so that it is easy to obtain a uniform film thickness.
Furthermore, the bubbles generated when the substrate 4 and the stamper 21 are superposed are discharged from the inner circumference to the outer circumference and to the outside of the disk by high-speed rotation, so that the problem of bubble defects also occurs if the viscosity is appropriate. do not do. Further, the processing time is shorter than that of the conventional method, and it can be made in about 30 seconds to 1 minute per surface.

Further, since the surplus resin is spun out, the amount of resin accumulated on the end face can be greatly reduced as compared with the conventional manufacturing method described above. In other words, edge treatment such as sucking is much easier and better. Further, the end surface treatment after the high speed rotation is necessary when the stamper 21 having the same outer diameter as the substrate 4 is used, but when the experiment is attempted using the stamper 21 having various diameters, the end surface treatment is completely unnecessary. It turns out that it is also possible. It is the outer diameter of the stamper 21, the substrate 4
It is the same as or slightly smaller than the outer diameter of. When such a stamper 21 is used, the resin does not accumulate on the end surface, so that burr does not occur during curing of the radiation curable resin, and a disk having a smooth end surface can be obtained. Therefore, by using such a stamper, the productivity of the optical disc can be significantly improved. Furthermore, the radiation curable resin can be shaken off by high-speed rotation as described above even when a transparent resin layer is directly laminated on a flat substrate and an uneven shape is formed by pits or guide grooves on the surface of this transparent resin layer. is there. That is, it can also be used as a method of manufacturing a multi-layered optical disc or a single-layered optical disc in which a transparent resin layer is laminated on a flat substrate and the surface of the transparent resin layer is the first information recording surface.

By the way, the radiation curable resin 21 used in the present invention may be any resin curable by radiation, such as an ultraviolet curable resin and an electron beam curable resin. However, the effect is sufficiently exhibited by the manufacturing method of the present invention. The resin viscosity is important for this. Next, this resin viscosity will be described with reference to FIG. FIG. 3 is a diagram for explaining the resin viscosity of the radiation curable resin used in the method for manufacturing an optical information recording medium of the present invention. Specifically, when radiation-curing resins having various viscosities are used in the above-described manufacturing method of the present invention, how the film thickness of the transparent resin layer 6 formed changes according to the rotation speed of high-speed rotation. Is shown. It is said that the thickness of the transparent resin layer 6 of the above-mentioned optical disc having a multilayer structure is about 35 to 50 μm in terms of signal reproduction, but according to the figure, the viscosity of the radiation curable resin and the number of rotations for shaking off the resin are good. , Shows that you can choose from a relatively wide range. On the other hand, focusing on the film thickness distribution of the formed radiation curable resin 6, the range of resin viscosity and rotation speed is limited to some extent. For example, when the thickness distribution of the formed transparent resin layer 6 is examined to be about 40 μm, the film thickness distribution is as shown in Table 1 below.

[0021]

[Table 1]

As described above, the film thickness distribution of the transparent resin layer 6 leads to fluctuations in the output of the reproduction signal, so it must be suppressed to ± 3 μm or less. When the appropriate resin viscosity and the number of rotations are judged from the above Table 1 from such a viewpoint, the resin viscosity is 80 to 1100.
It can be seen that the range of cP and the rotation speed of 750 to 1500 rpm is suitable. Here, the reason why the film thickness distribution of the formed transparent resin layer 6 changes depending on the conditions of the resin viscosity and the number of revolutions is not clear, but it is related to the rheology of the resin and the steady vibration of the substrate during high-speed rotation. It seems that there is.

On the other hand, regarding the problem of reliability, as a result of intensive studies aimed at solving the problem by subjecting the substrate 4 to a surface treatment, it was found that it can be solved by performing an appropriate primer treatment. The second embodiment of the present invention relating to the improvement of the reliability of this optical disc will be described below. FIG. 4 is a diagram showing the structure of an embodiment of the optical information recording medium of the present invention. As shown in FIG.
No. 0 has a structure in which the coupling film is directly formed between the semitransparent reflection layer 5 and the transparent resin layer 6 of the optical disc 1 or the resin containing the coupling agent is formed into a thin film in a primer film 9. There is.

That is, the semi-transparent reflection layer 5 is generally made of silicon oxide film (SiOx), silicon oxide film alloy,
The semi-transparent reflection layer 5 and the transparent resin layer 6 are different from each other in that the transparent resin layer 6 is made of a resin such as an ultraviolet curable resin and is made of a silicon nitride film (SiNx), a silicon nitride film-based alloy or the like. Adhesion is poor because it is composed of materials,
During the environmental load test, the transparent resin layer 6 was cracked or the transparent resin layer 6 was peeled off. Therefore,
In the optical disc 10, a primer film 9 that enhances the adhesiveness between different materials is formed between the semitransparent reflective layer 5 and the transparent resin layer 6 to improve the adhesiveness of the transparent resin layer 6. Further, when such a primer film 9 is provided, the resin itself that constitutes the transparent resin layer 6 does not need to have a high adhesive force, and a resin having a low adhesive force can be used. Therefore, when the transparent resin layer 6 is formed by using a resin having such a low adhesive force, the adhesiveness with the stamper becomes small at the time of formation, which is also advantageous in that the stamper can be easily peeled off.

The coupling agent of the primer film 9 is specifically selected from a silane coupling agent, a titanate coupling agent and an aluminate coupling agent, and the curable resin is an ultraviolet curable resin or an electron beam curable resin. , Thermosetting resin, etc. The film thickness of the primer film 9 is appropriately in the range of a single molecule (several angstroms) to several μm. The primer film 9 is applied by a vapor coating method or a spin coating method.

The primer film 9 is formed by the above vapor coating method.
For example, as shown in FIG. 5, the substrate 4 on which the semitransparent reflective layer 5 is formed may be formed by the coupling agent 31.
The semi-transparent reflective layer 5 is held horizontally in the sealed container 32 with a distance from the coupling agent 31 so that the reflective layer 5 is on the lower side. Then, when left for a predetermined time, the vapor of the coupling agent 31 adheres to the surface of the semitransparent reflective layer 5. In this way, the primer film 9 is formed. On the other hand, when the spin coating method is used, the coupling agent itself or the resin containing the coupling agent is dropped on the rotated substrate 4 having the semitransparent reflection layer, and applied to a predetermined thickness, if necessary. Accordingly, it is cured and formed.

After forming the primer film 9 on the semitransparent reflective layer 5 as described above, the primer film 9 is formed by using, for example, the optical disc manufacturing method described in the first embodiment (see FIG. 2). The transparent resin layer 6 having an uneven shape due to pits and guide grooves is formed on the film 9.

The primer film 9 is made of a silicon oxide film, a silicon oxide film-based alloy, a silicon nitride film (SiN).
x), it is provided in order to improve the adhesion between the silicon nitride film-based alloy and the like and the radiation resin. However, the adhesion in the case of directly adhering the substrate 4 and the transparent resin layer 6 like a single-layer disc, You may provide in order to raise.

Next, the present invention will be described in more detail with reference to specific examples. <Example 1> Two stampers having a shortest pit length of 0.451 µm and a track pitch of 0.84 µm were prepared. The inner diameter of the first stamper (for injection molding) is 35.6.
mm, outer diameter 128 mm, second stamper (2P
(For molding) had an inner diameter of 30 mm and an outer diameter of 120 mm. A 1.2 mm thick substrate 4 was manufactured by injection molding of polycarbonate using the first stamper. Subsequently, a semitransparent reflective layer 5 (film thickness 500 angstrom) made of a silicon oxide film (SiOx) was formed on this by sputtering.

Next, an airtight container with a lid having a diameter of 300 mm and a height of 50 mm was prepared, and as shown in FIG. 5, a silane coupling agent OAP (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was added to about 1 cm.
To the depth of. The structural formula of the silane coupling agent OAP is shown in Structural Formula 1 below.

[0031]

Embedded image

Then, the substrate 4 was left with the space of 3 cm from the liquid surface of the silane coupling agent OAP so that the semitransparent reflective layer 5 was on the lower side, and exposed to the vapor of OAP for 5 minutes. By this treatment, a monolayer of primer film 9 was deposited on the surface of the semitransparent reflective layer 5.

Subsequently, a spinner having a flat turntable with an outer diameter of 120 mm was prepared, and a second stamper was attached to the turntable so as to be flat. On the other hand, 97 parts of bifunctional acrylate R684 (manufactured by Nippon Kayaku Co., Ltd.), Darocu as a photopolymerization initiator
An ultraviolet curable resin composition consisting of 3 parts of r1173 (manufactured by Merck Japan Ltd.) was prepared. The viscosity of this ultraviolet curable resin composition was 146 cP at 23 ° C. The structural formula of the acrylate R684 is shown in the structural formula 2 below, and the structural formula of the Darocur 1173 is shown in the structural formula 3 below.

[0034]

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[0035]

Embedded image

Next, while rotating the turntable at 30 rpm, this ultraviolet curable resin composition was dropped onto the surface of the stamper at a position having a diameter of 80 mm for 5 seconds to apply the resin in a ring shape. Next, the substrate 4 on which the primer film 9 is formed is dropped so that the primer film 9 and the rotating ring-shaped resin face each other, and the rotation speed is immediately increased to 1000 rp.
It was raised to m and held for 15 seconds. By this high speed rotation, the surplus UV curable resin and the air bubbles mixed in the UV curable resin were spun out together. Subsequently, the turntable rotation was reduced to 100 rpm, and the ultraviolet light was changed to 10 rpm in the atmosphere.
It was irradiated for 2 seconds to cure the ultraviolet curable resin. Then, when the substrate was peeled off from the stamper, a substrate having the transparent resin layer 6 was obtained. The obtained substrate had no bubbles and no burr on the outer peripheral portion. In addition, the formed transparent resin layer 6
The film thickness was measured and found to be 38 μm ± 2 μm, which was uniform. On the other hand, the stamper after peeling did not have burrs on the outer peripheral portion and was in a surface state that could be reused as it was.

Finally, 700 angstrom of aluminum was formed as a second reflective layer 7 on the surface of the transparent resin layer by sputtering. And SD-1700 is used as the protective film 8.
(Dai Nippon Ink Co., Ltd.) is spin coated to form a film of 10 μm,
The dual layer disc 1 shown in FIG. 1 was completed.

This optical disk is laser wavelength 635n
m, and reproduction evaluation was performed with a disk evaluation machine having an objective lens numerical aperture NA of 0.52. It was possible to observe the signals on the respective information recording surfaces 2 and 3 separately by changing the focus position of the pickup. At this time, mutual interference between the two information recording surfaces 2 and 3 was not found, and the eye pattern was opened neatly on both information recording surfaces 2 and 3, and stable reproduction was possible. The reproduction jitter after passing through the equalizer is the first information recording surface 2
Was 7.5%, and the second information recording surface 3 was 6.8%, which was at a practically sufficient level. Also, 55 ℃, 95% RH,
In the environmental load test for 200 hours, the jitter was 0.
Although it increased by 6% to 0.5%, the reliability could be confirmed without causing problems such as fluffing and film peeling of the transparent resin layer 6.

<Example 2> Semi-transparent reflective layer 5 (film thickness: 500)
The process was performed in the same manner as in Example 1 up to the process of forming a film by sputtering. Next, silane coupling agent A-174 (manufactured by Nippon Unicar Co., Ltd.) 5 parts, 2
Functional acrylate HDDA (manufactured by Nippon Kayaku Co., Ltd.) 92
Part, and a photopolymerization initiator Darocur1173 (manufactured by Merck Japan Ltd.) 3 parts were prepared.
The structural formula of A-174 is shown in Structural Formula 4 below, and the structural formula of HDDA is shown in Structural Formula 5 below.

[0040]

Embedded image

[0041]

Embedded image

The above-mentioned primer solution was dropped on the semitransparent reflective layer 5 using a spinner and shaken off at a high speed of 2000 rpm. Then, the rotation is reduced to 100 rpm, ultraviolet rays are irradiated for 10 seconds in the atmosphere, and the primer film 9 is cured.
Was formed (film thickness of about 1 μm). Then, the rotation of the spinner was reduced to 30 rpm, 97 parts of a bifunctional acrylate R551 (manufactured by Nippon Kayaku Co., Ltd.), and a photopolymerization initiator Darocur.
1173 (manufactured by Merck Japan Ltd.) 3 parts UV curable resin composition (resin viscosity at 23 ° C. is 1100
cP) was applied in a ring shape at a position having a diameter of 70 mm for 5 seconds, and the spinner was stopped. The structural formula of R551 is shown in Structural Formula 6 below.

[0043]

[Chemical 6]

Subsequently, the inner diameter is 25 mm and the outer diameter is 119 m.
A spinner having a turntable with an outer diameter of 119 mm in which a second stamper machined to m was attached flat was prepared. Then, the surface of the second stamper and the ring-shaped resin surface coated on the substrate were superposed so as to face each other, and immediately subjected to high-speed rotation at 1500 rpm for 30 seconds. As a result, the surplus UV curable resin and the mixed air bubbles were also spun out. Finally, ultra-high speed rotation of 5000 rpm was performed for 1 second to stop the rotation. Subsequently, this set was placed in a nitrogen atmosphere and irradiated with ultraviolet rays for 5 seconds to cure the ultraviolet curable resin. Then, when the substrate was peeled from the stamper, the substrate 4 having the transparent resin layer 6 in which the pits 4B were formed was obtained. When the formed transparent resin layer 6 was observed, there were no bubbles and no burrs on the outer peripheral portion. Further, the film thickness of the transparent resin layer 6 was measured and found to be 40 μm ± 3 μm, which was uniform. On the other hand, the stamper after peeling did not have burrs on the outer peripheral portion and was in a surface state that could be reused as it was. Finally, in the same manner as in Example 1, the reflective layer 7 and the protective film 8 were formed to complete the optical disc 1.

After the high speed rotation of 1500 rpm, 5
The reason why the ultra-high speed rotation of 000 rpm is applied is that the resin having a high viscosity is likely to swell at the outer peripheral end due to the surface tension. The rise of the outer peripheral end portion due to the surface tension is not such an amount that it becomes a burr after the radiation curable resin is cured, but an extra mold releasing force is required when the stamper is peeled off. So 4000-10000 rpm
The ultra-high speed rotation was added for a very short time to completely shake off the resin that swelled up at the edges. The reason for UV curing in a nitrogen atmosphere is that oxygen in the air is shut off,
Although it is for increasing the curing speed, similar effects can be obtained not only with nitrogen but also with argon, carbon dioxide, or the like.

When the optical disk manufactured as described above was reproduced and evaluated by a disk evaluation machine having a laser wavelength of 635 nm and an objective lens numerical aperture NA of 0.52 as in Example 1, it was found to be stable as in Example 1. I was able to play it. The reproduction jitter after passing through the equalizer was 7.7% on the first information recording surface 2 and 7.1% on the second information recording surface 3,
It was at a level where it was practically used. Also 55 ℃, 95% R
In the environmental load test for H and 200 hours, the jitter increased by 0.8% and 0.7%, respectively, but there was no problem such as fluffing or film peeling of the transparent resin layer 6, and the reliability could be confirmed. .

The two embodiments have been described above.
The present invention is not limited to these two examples. For example, in Examples 1 and 2 described above, an ultraviolet curable resin was used as the radiation curable resin for forming the transparent resin layer 6, but the composition is not limited to the sensitive unsaturated resin and the photopolymerization initiator, and the polymerization is not limited. A small amount of additives such as an accelerator, a releasing agent and an anti-yellowing agent may be added. Further, as described above, an electron beam curing resin or the like may be used. Further, the resin applied as the primer film 9 is not limited to the ultraviolet curable resin, and an electron beam curable resin, a thermosetting resin or the like may be used, and may be diluted with a solvent or the like and used as necessary. In addition to the silane coupling agent, a titanate coupling agent, an aluminate coupling agent, or the like can be used as the coupling material. Further, after applying the primer film 9, baking may be performed if necessary to enhance the adhesion.

[0048]

As described above, according to the method for manufacturing an optical information recording medium of the present invention, a radiation curable resin layer is laminated on a substrate made of a light transmissive material, and the radiation curable resin layer is formed on the radiation curable resin layer. In a method for manufacturing an optical information recording medium which is used as an information recording surface for recording information by forming a concavo-convex shape by a guide groove or a pit, after a substrate and a stamper are superposed on each other with a radiation curable resin sandwiched therebetween, Since the substrate and the stamper are rotated at a high speed in a superposed state, it is possible to form a radiation curable resin layer having a uniform film thickness and containing no bubbles in a short manufacturing process.

Further, a semi-transparent reflective layer and a radiation curable resin layer are sequentially laminated on a substrate made of a light transmissive material, and an uneven shape is formed on the radiation curable resin layer by a guide groove or a pit to provide information. In the optical information recording medium used as the information recording surface for recording, since the primer film is formed between the semitransparent reflection layer and the radiation curable resin layer, the radiation curable resin layer may be cracked or radiation cured. The resin layer can be prevented from peeling off, and the reliability of the optical information recording medium can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the structure of an optical disc having a multi-layered structure manufactured by the present invention and a conventional optical information recording medium.

FIG. 2 is a first method of manufacturing an optical information recording medium of the present invention.
It is a figure for explaining the Example of.

FIG. 3 is a diagram for explaining the resin viscosity of the radiation curable resin used in the method for producing an optical information recording medium of the present invention.

FIG. 4 is a diagram showing the structure of an embodiment of the optical information recording medium of the present invention.

FIG. 5 is a second manufacturing method of the optical information recording medium of the present invention.
It is a figure for explaining the Example of.

FIG. 6 is a diagram showing an example of a conventional method for manufacturing an optical information recording medium.

[Explanation of symbols]

 1, 10 Optical disc (optical information recording medium) 2 First information recording surface 3 Second information recording surface 4 Light transmissive substrate 5 Semitransparent reflective layer 6 Transparent resin layer (radiation curable resin layer) 7 Reflective layer 9 Primer Membrane 21 Stamper 22 Radiation curable resin 31 Primer solution

Claims (6)

[Claims] 1. An information recording for recording information by laminating a radiation curable resin layer on a substrate made of a light transmissive material, and forming an uneven shape by guide grooves or pits on the radiation curable resin layer. In the method for producing an optical information recording medium having a surface, a step of dropping a radiation curable resin on the surface of the stamper or the substrate for forming the uneven shape of the radiation curable resin layer, and the dropped radiation curable resin A step of superposing the substrate and the stamper so as to face each other with the substrate sandwiched therebetween, a step of rotating the substrate and the stamper at high speed in a state of being superposed, and a step of irradiating radiation to cure the radiation curable resin. A method for manufacturing an optical information recording medium, characterized by having in this order. 2. The method for manufacturing an optical information recording medium according to claim 1, wherein the radiation curable resin has a viscosity of 80 to 1100 cP. 3. The method for manufacturing an optical information recording medium according to claim 1, wherein the outer diameter of the stamper is the same as or slightly smaller than the outer diameter of the substrate. Optical information recording medium manufacturing method. 4. A semitransparent reflective layer and a radiation curable resin layer are sequentially laminated on a substrate made of a light transmissive material, and an uneven shape is formed on the radiation curable resin layer by a guide groove or a pit to provide information. An optical information recording medium used as an information recording surface for recording, wherein a primer film is formed between the semitransparent reflective layer and the radiation curable resin layer. 5. The optical information recording medium according to claim 4, wherein the primer film comprises a coupling agent selected from a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, or a resin containing the coupling agent. An optical information recording medium, which is a coated film. 6. A translucent reflective layer, a primer film, and a radiation curable resin layer are sequentially laminated on a substrate made of a light transmissive material, and an uneven shape is formed on the radiation curable resin layer by guide grooves or pits. A method of manufacturing an optical information recording medium, comprising the step of forming the primer film on the semitransparent reflective layer on the substrate, and the surface of a stamper for forming the uneven shape of the radiation curable resin layer or A step of dropping a radiation curable resin on the primer film, and a step of forming the uneven shape on the radiation curable resin layer by facing and superposing the substrate and the stamper to cure the radiation curable resin. A method for manufacturing an optical information recording medium, characterized by having in this order.