JP2009224004A - Method for manufacturing optical information recording medium, and device for manufacturing optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-density recordable optical information recording medium, in which an excellent thin resin layer is formed, by eliminating the influence of a micro protrusion formed on the inside of a disk substrate during the in injection molding of the disk substrate. <P>SOLUTION: The method for manufacturing the optical information recording medium comprises steps: to injection-mold a first disk substrate; to injection-mold a second disk substrate which has a circular recession on a section corresponding to a circular protrusion produced on the inner radius side of a signal recording surface of the first disk substrate; to form a resin layer on the signal recording surface of the first disk substrate or on the surface of the second disk substrate having the circular recession; and to place the signal recording surface of the first disk substrate and the recession of the second disk substrate opposite to each other, and superpose the first disk substrate and the second disk substrate in the state in which the first and second disk substrates are aligned in such a way that at least the vertex of the protrusion is nestled in the recession. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical information recording medium and a manufacturing apparatus optical information recording medium suitable for improving the quality of a high quality optical information recording medium, in particular, a high recording density optical information recording medium.

  In recent years, the development of DVD (Digital Versatile Disc) has been remarkable and is becoming widespread, and is being produced on a mass production scale. An example of a DVD manufacturing method that is currently widely used is that a stamper having a groove for forming an information signal is generally attached to an injection mold, and a disk substrate having a thickness of 0.6 mm is formed by injection molding. After a reflective film is formed on the surface where the groove exists, a finished product is obtained by laminating two disk substrates with a light-colored or transparent (hereinafter referred to as transparent) adhesive. As described above, various production line mechanisms have already been proposed for an apparatus for manufacturing a DVD by bonding two disk substrates (see, for example, Patent Document 1 and Patent Document 2).

For example, in the case of a BD (Blue-ray Disc), an optical information recording medium corresponding to a high recording density is from a thin resin layer formed on a disk substrate having a thickness of about 1.1 mm by a laser beam having a wavelength of 405 nm. In order to record and reproduce information, a transparent light transmission layer having a thickness of 100 μm (0.1 mm) is formed on the reflective film of the first signal recording layer on the first layer on the disk substrate formed by the stamper. To do. Further, in an optical information recording medium compatible with high-density recording having two signal recording layers, another light transmission layer having a second signal recording layer on the first signal recording layer on the first layer on the disk substrate. It is necessary to form a layer, a translucent reflection film, and a transparent cover layer, and the light transmission layer and the cover layer must be approximately 100 μm in thickness. In addition, the uniformity of the thicknesses of the light transmission layer and the cover layer has a great influence on the recording / reproduction of information, so that a very high uniformity is required. For example, the thickness of the resin layer serving as the light transmission layer is approximately 25 μm, and the thickness of the resin layer serving as the cover layer is approximately 75 μm.
JP 2002-245692 A JP 2006-252700 A

  However, at the time of injection molding of a disk substrate used in the manufacture of an optical information recording medium compatible with high-density recording, the distortion of the disk substrate generated at the time of injection molding greatly influences, so that the centering accuracy of the holding position of the stamper can be improved. At the same time, it is required that the signal recording area defined by the standard is not distorted. Such a stamper is centered and held in a predetermined position by inserting a stamper holder having a special shape into the center hole on the inner periphery and applying pressure to the inner periphery of the center hole. Therefore, the vicinity of the center hole of the stamper is distorted by the pressure applied to the inner peripheral surface of the center hole of the stamper, and the signal recording of the injection-molded disk substrate 1 as shown in FIG. A minute protrusion Pa is formed on the surface 1A. As shown in FIG. 3A, a minute protrusion Pb is also formed on the signal recording surface 2A of the transfer disk substrate 2 manufactured by the same injection molding method. If the diameters of the disk substrate 1 and the transfer disk substrate 2 are equal to each other, the protrusions Pa and the protrusions Pb are formed at substantially equal positions from the central axis L passing through the centers of the disk substrate 1 and the transfer disk substrate 2, respectively. The

  As shown in FIG. 3D, the resin layer 3 is formed so as to cover the signal recording surface 1A of the disk substrate 1 having such a minute protrusion Pa, and as shown in FIG. A thin resin layer 4 is formed so as to cover the signal recording surface 2A of the transfer disk substrate 2 having minute protrusions Pb, and the disk substrate 1 and the transfer disk substrate are interposed between the resin layer 3 and the resin layer 4. 2 are overlapped and pasted. In this bonding step, as shown in FIG. 3E, the center axis L passing through the center of the disc substrate 1 and the center axis L passing through the center of the disc substrate 1 are aligned, and both disc substrates are overlapped. Match. Inevitably, the tops of the protrusions Pa of the disk substrate 1 and the protrusions Pb of the transfer disk substrate 2 abut each other.

  As described above, when the protrusions Pa and the tops of the protrusions Pb are abutted with each other, bubbles V are generated between the resin layer 3 and the resin layer 4 in the vicinity of the protrusions Pa and Pb. In some cases, a resin layer is formed on only one of the disk substrate 1 and the transfer disk substrate 2 and the other is bonded without forming a resin layer. In this case, the resin layer 3 in the vicinity of the protrusion Pa is used. And the signal recording surface 1A of the disk substrate 1, or an air layer remains between the resin layer 4 in the vicinity of the protrusion Pb and the signal recording surface 2A of the transfer disk substrate 2. As described above, there is a problem that when the transfer disk substrate is peeled off, the signal recording area is adversely affected by the mixture of bubbles and air. In addition, there is a problem that the quality is deteriorated, for example, thickness unevenness occurs in the resin layer that finally becomes a light transmission layer, or the appearance of the optical information recording medium is impaired.

  In view of the above-described problems, the present invention relates to a method for manufacturing an optical information medium compatible with high-density recording with a thin light transmission layer as compared with the prior art, and avoids an annular protrusion generated on a disk substrate during injection molding, thereby mixing bubbles. It is an object of the present invention to provide an optical information recording medium manufacturing method and an optical information recording medium manufacturing apparatus capable of preventing the deterioration of quality such as thickness unevenness and appearance deterioration.

  The first invention includes a step of injection-molding the first disk substrate, and an annular protrusion formed on the inner peripheral side of the signal recording surface of the first disk substrate during the injection molding of the first disk substrate, A step of injection-molding a second disk substrate having an annular recess at a location corresponding to, and applying a resin for forming a resin layer between the first disk substrate and the second disk substrate And the signal recording surface of the first disk substrate and the surface having the recess of the second disk substrate are opposed to each other, and at least the top portion of the protrusion is positioned in the recess. Provided is a method for manufacturing an optical information recording medium comprising a step of superposing and bonding the first disk substrate and the second disk substrate in a state of being combined.

  By being configured in this manner, the annular protrusion formed on the first disk substrate is bonded so that it fits in the annular recess of the second disk substrate, so that the resin layer near the protrusion is attached to the resin layer. It can be prevented that bubbles V are generated or an air layer remains between the resin layer in the vicinity of the protruding portion and the disk substrate to adversely affect the signal recording area. Further, it is possible to prevent the quality from being deteriorated, for example, the thickness unevenness of the resin layer that finally becomes the light transmission layer or the appearance of the optical information recording medium is impaired.

  According to a second invention, in the first invention, a first resin layer is formed so as to cover the signal recording surface of the first disk substrate and the annular projection, and the second disk substrate Provided is a method for producing an optical information recording medium, wherein a second resin layer is formed on the outer peripheral side of the annular recess on a surface having the annular recess.

  By comprising in this way, since the 2nd resin layer is formed in the outer peripheral side avoiding the projection part of the 1st disk substrate covered with the 1st resin layer, in addition to the above-mentioned effect, Air bubbles can be prevented from being generated between the protrusions formed on the first disk substrate and the recesses of the second disk substrate, and a uniform resin layer can be formed as a whole.

  According to a third invention, in the first invention, the thickness of the resin layer between the first disk substrate and the second disk substrate is thinner than the height of the protruding portion. A manufacturing method is provided.

  With this configuration, an optical information recording medium compatible with high-density recording with a thin light-transmitting layer that can achieve the above-described effects can be obtained without being affected by the annular protrusions of the first disk substrate. Can do.

  In a fourth aspect based on the first aspect, the second disk substrate is a transfer disk substrate on which another signal recording layer is formed, which is more than the annular recess of the transfer disk substrate. A second resin layer is formed on the outer peripheral side, a first resin layer is formed so as to cover the signal recording surface and the annular protrusion of the first disk substrate, and the transfer disk substrate is mounted on the first disk substrate. A method for producing an optical information recording medium is provided, wherein the other signal recording layer is transferred to the second resin layer that is peeled off from the second resin layer and remains on the first resin layer. .

By being configured in this manner, the annular protrusion formed on the first disk substrate is bonded so that it fits in the annular recess of the second disk substrate, so that the resin layer near the protrusion is attached to the resin layer. Prevents the generation of air bubbles V or adverse effects on the signal recording area when the transfer disk substrate is peeled off due to an air layer remaining between the resin layer in the vicinity of the protrusion and the disk substrate. can do. Further, it is possible to prevent the quality from being deteriorated, for example, the thickness unevenness of the resin layer that finally becomes the light transmission layer or the appearance of the optical information recording medium is impaired.

  According to a fifth aspect of the present invention, there is provided a first injection molding apparatus for forming a first disk substrate, and an annular shape generated on an inner peripheral side of a signal recording surface of the first disk substrate when the first disk substrate is formed. A second injection molding apparatus for forming a second disk substrate having an annular recess at a position corresponding to the protrusion, and a resin layer between the first disk substrate and the second disk substrate. A resin applying means for applying a resin for forming, the signal recording surface of the first disk substrate and the surface having the recess of the second disk substrate facing each other, and at least a top portion of the protrusion Is provided so as to fit in the recess, and an optical information recording medium manufacturing apparatus is provided that includes a laminating apparatus that superimposes the first disk substrate and the second disk substrate.

  By being configured in this manner, the annular protrusion formed on the first disk substrate is bonded so that it fits in the annular recess of the second disk substrate, so that the resin layer near the protrusion is attached to the resin layer. It can be prevented that bubbles V are generated or an air layer remains between the resin layer in the vicinity of the protruding portion and the disk substrate to adversely affect the signal recording area. Further, it is possible to prevent the quality from being deteriorated, for example, the thickness unevenness of the resin layer that finally becomes the light transmission layer or the appearance of the optical information recording medium is impaired.

  According to the present invention, the other disk substrate is provided with an annular recess at a position corresponding to the annular protrusion formed on the one disk substrate, and the disk substrate and the disk substrate are arranged so that the protrusion is received in the recess. Since a bubble V is generated in the resin layer near the protrusion or an air layer remains between the resin layer near the protrusion and the disk substrate, the transfer disk substrate is It is possible to prevent the signal recording area from being adversely affected when peeled. Further, it is possible to prevent the quality from being deteriorated, for example, the thickness unevenness of the resin layer that finally becomes the light transmission layer or the appearance of the optical information recording medium is impaired.

[Embodiment]
1 and 2, an embodiment of a method for manufacturing an optical information recording medium compatible with high-density recording according to the present invention will be described. FIG. 1 is a diagram showing an example of the present invention relating to a method for bonding both disk substrates. FIG. 2 is a diagram for explaining a manufacturing process from an injection molding process to a bonding process. The disk substrate 1 is injection-molded by the first injection molding apparatus 5A provided with the stamper and the stamper holder as described above (step 1). FIG. 1B shows a disk substrate 1 having an annular protrusion generated during injection molding. The first disk substrate 1 includes a signal recording surface 1A on which an information recording layer having desired information is formed, and a minute protrusion Pa is formed on the signal recording surface 1A side.

  The protrusion Pa is formed with a width W from the position of the distance D with respect to the central axis L passing through the center point of the disk substrate 1. This distance D is approximately 11 mm, for example. The protrusion Pa has an annular shape with a triangular cross section that gently slopes outward from the top located on the central axis L side. The top of the protrusion Pa is, for example, about 30 to 50 μm in height and 150 to 400 μm in width. The disk substrate 1 may be either 1.1 mm thick or 0.6 mm thick, but the first disk substrate 1 of the embodiment has a thickness of 1.1 mm.

  The second disk substrate 2 is a transfer disk substrate having an outer diameter and an inner diameter that are approximately the same size as the disk substrate 1. The second disk substrate 2 is injection-molded by a second injection molding device 5B different from the first injection molding device 5A for the first disk substrate (step 1). As shown in FIG. 1A, the second disk substrate 2 injection-molded by the second injection molding apparatus 5B includes a signal recording surface 2A on which an information recording layer having desired information is formed. An annular recess Q is formed on the signal recording surface 2A side.

  The annular recess Q is formed with a size of a width X extending in the radial outward direction from a distance d that is approximately the same as or smaller than the distance D from the central axis L of the protrusion Pa of the disk substrate 1. The width X of the recess Q is preferably about the same as the width W of the protrusion Pa of the disk substrate 1, but is not limited to this and may be smaller than the width W of the protrusion Pa. Further, the depth of the recess Q may be approximately the same as the height of the top of the protrusion Pa, but it is not necessary to limit to this. Note that the inner diameter of the second disk substrate 2 may be smaller than the inner diameter of the first disk substrate 1 depending on a peeling method employed for peeling the second disk substrate 2 described later.

  Next, as shown in FIG. 2, a transparent resin layer 3 excellent in light transmittance is formed so as to cover the signal recording surface 1A and the protrusions Pa of the first disk substrate 1 (step 2). The resin layer 3 is formed by a well-known spin coating method, and an ultraviolet curable liquid resin supplied in an annular shape by the nozzle 6 near the protrusion Pa is spread by a centrifugal force to have a desired thickness. Layer 3 is formed. The resin layer 3 covers the entire surface of the signal recording surface 1A outside the first disk substrate 1 from the protrusion Pa. The resin layer 3 is excellent in adhesiveness, and has a thickness of about 20 μm as an example.

  Similarly, a transparent resin layer 4 having excellent light transmittance is formed on the signal recording surface 2A from the vicinity of the outer peripheral end of the recess Q of the second disk substrate 2 (step 2). At this time, it is preferable that the resin of the resin layer 4 does not flow into the recess Q. However, the resin flowing into the recess Q is set by setting the depth of the recess Q in consideration of the flow of the resin. The adverse effects of can be eliminated. The resin layer 4 has low adhesion to the signal recording surface 2A of the second disk substrate 2 and has a characteristic that it can be peeled off from the signal recording surface 2A of the second disk substrate 2 relatively easily. When the resin layer 3 has a thickness of about 20 μm, the resin layer 4 has a thickness of about 5 μm, and the resin layer 3 has a thickness of about 25 μm so that the sum of the thickness of the resin layer 3 and the thickness of the resin layer 4 is about 25 μm. The thickness of the layer 3 and the resin layer 4 is adjusted.

  These numerical values are examples, and the thicknesses of the resin layer 3 and the resin layer 4 are not limited to these numerical values, and the effects of the present invention become more remarkable if the thicknesses are further reduced. Further, the resin layer 3 is formed on the first disk substrate 1 and the resin layer 4 is formed on the transfer disk substrate 2, but the resin layer is formed only on one of the first disk substrate 1 and the transfer disk substrate 2, Even if it is not formed on the other side, the same effect can be obtained.

  Next, as shown in FIG. 2, the first disk substrate 1 and the second disk substrate 2 each having a resin layer formed thereon are superposed and bonded together (step 3). In this embodiment, a vacuum bonding method is used to bond the first disk substrate 1 and the second disk substrate 2 together. As shown in FIG. 1E, the resin layer 3 and the resin layer 4 are brought into contact with each other, and the first disk substrate 1 and the second disk substrate 2 are overlapped. At this time, the central axis L of the first disk substrate 1 and the central axis L of the second disk substrate 2 are made to coincide with each other, and the desired disk space between the first disk substrate 1 and the second disk substrate 2 is obtained. Applying pressure for a short time and bonding. At this time, the resin layer 3 is not cured at least and effectively functions as an adhesive layer.

  If the central axis L of the first disk substrate 1 and the central axis L of the second disk substrate 2 are made to coincide with each other in this bonding step, it is inevitable depending on the position of the protrusion Pa and the position of the recess Q described above. The protrusion Pa of the first disk substrate 1 and the recess Q of the second disk substrate 2 coincide with each other, and at least a part of the resin layer 3 covering the protrusion Pa and the protrusion Pa is in the recess Q. Fit. Therefore, since the resin layer 3 and the resin layer 4 which are in contact with each other in a vacuum are almost flat, no bubbles are generated between them, and the signal recording surface 1A of the resin layer 3 and the first disk substrate 1 is not generated. Or an air layer does not remain between the resin layer 4 and the signal recording surface 2A of the second disk substrate 2.

  Here, the second resin layer 4 is formed on the outer peripheral side of the first disk substrate 1 so as to avoid the protrusion Pa of the first disk substrate 1 covered with the first resin layer 3. It is possible to prevent bubbles from being generated between the protruding portion Pa and the recess Q of the second disk substrate 2. Further, since the protrusion Pa of the first disk substrate 1 is covered with the first resin layer 3, the first resin layer 3 covering the protrusion Pa is located between the protrusion Pa and the recess Q. The air layer can be suppressed to a small level, and the appearance of the optical information recording medium can be prevented from being inferior. Further, the thickness of the resin layer composed of the resin layer 3 and the resin layer 4 between the signal recording surface 1A of the first disk substrate 1 and the signal recording surface 2A of the disk substrate 2 in the vicinity of the protrusion Pa is uniform. . As a result, the quality of the optical information recording medium compatible with high-density recording can be improved.

  As described above, after the first disk substrate 1 and the second disk substrate 2 are bonded together, the resin layers 3 and 4 between the substrates are cured by irradiating with radiation such as ultraviolet rays by a desired method. Let Next, in this embodiment, since the second disk substrate 2 is a transfer disk substrate, the second disk substrate 2 is separated from the first disk substrate 1 by a peeling method combining mechanical force and compressed air, for example. The substrate 2 is peeled off. At this time, peeling occurs between the resin layer 4 formed on the signal recording surface 2 A of the second disk substrate 2 and the second disk substrate 2, and the resin layer 4 remains adhered to the resin layer 3 and the first 1 remains on the disk substrate 1.

  Therefore, information on the signal recording surface 2A of the second disk substrate 2 is transferred to the surface of the resin layer 4 as a signal recording layer. According to this embodiment, the bubble V is generated in the resin layer in the vicinity of the protrusion, or the air layer does not remain between the resin layer in the vicinity of the protrusion and the disk substrate. It is possible to prevent the signal recording area from being adversely affected when peeled. Therefore, a cover layer (not shown) is formed on the resin layer 4 in the subsequent steps, and an optical information recording medium compatible with high density recording having two signal recording layers is obtained.

  In the above-described embodiment, the second disk substrate 2 is a transfer disk substrate, and is finally peeled off, and the recess Q is formed in the disk substrate that does not constitute a part of the optical information recording medium. A recess similar to the recess Q may be formed on a disk substrate constituting a part of the final optical information recording medium.

  In the above embodiment, the recess Q formed in the second disk substrate 2 is described as an annular shape. However, particularly when the second disk substrate 2 is a transfer disk substrate, FIG. The portion from the width X to the inner periphery shown in (A) may be at the same level as the depth of the recess Q, that is, the recess Q may be a recess extending to the inner peripheral end. In this case, since the inner peripheral portion corresponding to the recess Q of the second disk substrate 2 is thin, there is a minute gap on the inner peripheral side of the first disk substrate 1 and the second disk substrate 2. Therefore, when the first disk substrate 2 is peeled off, not only the mechanical initial peeling is easy, but also because the compressed air uniformly enters between the disk substrates, it is easy to peel off uniformly. is there. However, the present invention is not limited to the peeling method.

  In the above embodiment, the first disk substrate 1 and the second disk substrate 2 are bonded using a well-known vacuum bonding method. However, bonding is performed using a conventional spin method. May be. In the case of an optical information recording medium with a thin light transmission layer, when the minute protrusions of both disk substrates are brought into contact with each other, this spinning method also causes the resin to spread outward due to centrifugal force. An air layer may be generated between the disk substrate and the resin layer. However, according to the present invention, even if a resin layer having a thickness equal to or less than the height of the minute protrusions is formed between the disk substrates by a spinning method, bubbles may be generated in the resin layer due to the influence of the protrusions. No air remains between the disk substrate and the resin layer.

  Further, as in the above-described embodiment, an optical information recording medium compatible with high-density recording having a structure in which a disk substrate to which a second signal recording layer is transferred is bonded with an adhesive may be used. These structures can be employed for a write-once type high recording density optical information recording medium, a read-only high recording density optical information recording medium, a rewritable high recording density optical information recording medium, or the like. Furthermore, it goes without saying that the manufacturing method of the present invention can also be employed in the manufacturing process of an optical information recording medium having a structure such as a general DVD.

It is a figure for demonstrating the manufacturing method of the optical information recording medium based on this invention. It is a figure for demonstrating the manufacturing process of an optical information recording medium. It is a figure for demonstrating the conventional manufacturing method of an optical information recording medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st disc substrate 1A ... Signal recording surface of 1st disc substrate 2 ... 2nd disc substrate 2A ... Signal recording surface of 2nd disc substrate 3 ... 1st The transparent resin layer formed on the disk substrate 4 ... The transparent resin layer formed on the second disk substrate 5A ... The first injection molding device 5B ... The second injection molding device Pa. ..Protrusions on the disk substrate Q: Recesses formed on the disk substrate W: Width of the protrusions Pa X: Width of the recesses Q

Claims (5)

A step of injection molding a first disk substrate;
A second disk substrate having an annular recess at a position corresponding to an annular protrusion formed on the inner peripheral side of the signal recording surface of the first disk substrate during injection molding of the first disk substrate is injected. Molding process;
Applying a resin for forming a resin layer between the first disk substrate and the second disk substrate;
In a state where the signal recording surface of the first disk substrate and the surface having the recess of the second disk substrate are opposed to each other, and at least the top portion of the protrusion is aligned in the recess. A step of superposing and bonding the first disk substrate and the second disk substrate;
A method for manufacturing an optical information recording medium comprising: In claim 1,
Forming a first resin layer so as to cover the signal recording surface of the first disk substrate and the annular protrusion;
A method of manufacturing an optical information recording medium, wherein a second resin layer is formed on a surface of the second disk substrate having the annular recess on the outer peripheral side of the annular recess. In claim 1,
A method of manufacturing an optical information recording medium, wherein a thickness of a resin layer between the first disk substrate and the second disk substrate is thinner than a height of the protrusion. In claim 1,
The second disk substrate is a transfer disk substrate on which another signal recording layer is formed,
Forming a second resin layer on the outer peripheral side of the annular recess of the transfer disk substrate;
Forming a first resin layer so as to cover the signal recording surface of the first disk substrate and the annular protrusion;
The optical information is characterized in that the transfer disk substrate is peeled off from the second resin layer, and the other signal recording layer is transferred to the second resin layer remaining on the first resin layer. A method for manufacturing a recording medium. A first injection molding apparatus for forming a first disk substrate;
A second disk substrate having an annular recess at a position corresponding to an annular protrusion formed on the inner peripheral side of the signal recording surface of the first disk substrate during the formation of the first disk substrate is formed. A second injection molding device;
A resin application means for applying a resin for forming a resin layer between the first disk substrate and the second disk substrate;
In a state where the signal recording surface of the first disk substrate and the surface having the recess of the second disk substrate are opposed to each other, and at least the top portion of the protrusion is aligned in the recess. A laminating apparatus for superimposing the first disk substrate and the second disk substrate;
An optical information recording medium manufacturing apparatus comprising:

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