JP2002100074A - Molded substrate for lamination type optical information recording medium, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the structure of a molded substrate in such a manner that an adhesive does not give adverse influences to the inner circumference face of a lamination type optical information recording medium having a molded substrate with a flat lamination face and that the adhesion region can be formed near the inner circumference end as close as possible. SOLUTION: On the premise that the molded substrate has a flat face having no trace of the pressing member of a stamper as the master pattern of the relief pattern in the die on the surface having a relief pattern for recording and reproducing of information. Further, an annular minute recess is formed in a little outer circumference part from the center hole of the relief pattern face of the molded substrate. An adhesive is applied in an annular state in the outer part of the recess and spread to form a uniform thin adhesive layer all over the outer region of the annular recess and then two molded substrates are adhered. The inner circumference edge of the adhesive layer is located near the center hole of the molded substrate and further spread inward in the radial direction in the adhesion process. However, the adhesive in inhibited from spreading by the annular recess and is certainly prevented from squeezing to the inner circumference face of the center hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded substrate used for manufacturing a laminated optical information recording medium and a method of manufacturing the same, and more particularly to a molded substrate used in an optical information recording medium driving device of a portable information terminal device. It is possible to effectively avoid the problem that may occur when the optical information recording medium is used, that is, damage to the bonding surface of the inner peripheral portion of the optical information recording medium.

[0002]

2. Description of the Related Art An optical information recording medium such as a DVD employed in a high-density optical information recording medium is the above-described recording medium in which one product is formed by laminating two substrates. The external shape is a conventional compact disk (hereinafter referred to as "CD")
However, since the two substrates are bonded to each other, the following problems have been considered. That is, in the portable optical information terminal device, a special holding method is employed for holding the optical information recording medium 1 in the driving device in order to satisfy the demand for miniaturization. In the method, a slide projection member 3 is provided on a side surface of a center shaft 2 of a turntable T which is fitted to the inner periphery of the optical information recording medium 1 so as to be able to protrude and retract in the radial direction. This is a method in which the projection member 3 presses and holds and fixes the upper end of the inner diameter of the optical information recording medium 1 while properly placed on the T (FIGS. 1a, 1b, 1c). When the attachment / detachment of the optical information recording medium 1 (attachment / removal of the optical information recording medium) is repeated in the reproducing apparatus provided with this holding method, the C
No special problem occurred in D
In this case, the sliding protrusion member 3 tends to push the gap between the adhesive layers of the optical information recording medium 1 in which two substrates are bonded together (FIG. 2A). In the worst case, as shown in an exaggerated manner in the right half of FIG. 2B, the sliding projection member 3 is caught on the inner peripheral edge, deforming the inner peripheral portion, and damaging the optical information recording medium 1. There is a risk of doing it. Such a phenomenon is caused by the fact that the inner peripheral edge of the adhesive layer is withdrawn by several millimeters or more in the radial direction from the inner periphery of the DVD in order to reliably prevent the adhesive from protruding into the inner periphery (for example, the inner diameter of the DVD). 15 mm, the inner diameter of the adhesive layer is 22 to 37 mm). In order to solve the above-mentioned problem, a method of starting the bonding region of the substrate from the inner peripheral edge as much as possible has been attempted. However, according to this method, a part of the adhesive may protrude into the inner peripheral portion (the inner peripheral surface of the center hole) of the optical information recording medium 1 and may be hardened. Optical information recording medium 1 that defines a medium holding reference (center of rotation) for recording medium 1
In this case, the perfect circular shape of the center hole is damaged, and the reproduction accuracy is significantly impaired. On the other hand, if the amount of the adhesive is reduced to prevent the adhesive from protruding to the inner peripheral surface of the center hole, the adhesive region is brought as close as possible to the inner peripheral end due to insufficient adhesive. The intended purpose of preventing biting of the member 3 cannot always be achieved. From the above,
It is difficult to solve the above problem by devising the way of applying the adhesive, it is difficult to ensure the reliability, and since it is inferior in productivity, it is possible to reliably prevent the adhesive from protruding to the center inner surface, Another solution in the direction of devising the substrate so that the adhesive layer can be interposed as much as possible to the vicinity of the inner periphery is required.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention
For the optical information recording medium of the lamination type of the molded substrate having a flat lamination surface side, the laminating adhesive does not adversely affect the inner peripheral surface, so that the bonding area can be brought as close as possible to the inner peripheral edge.
An object of the present invention is to devise the structure of a molded substrate. Still another object of the present invention is to devise a shape of a stamper for molding the molded substrate, and to devise a method of manufacturing the stamper.

[0004]

[Means for solving the problem] [Solution for molded substrate] A solution for the molded substrate is a molded substrate for an optical information recording medium in which two substrates are laminated to constitute one recording medium. A molded substrate having a flat surface that does not leave traces of a pressing member of a stamper serving as a base of a relief pattern in a mold on a surface having a relief pattern provided for recording and reproducing information. The premise is that an annular minute recess is provided slightly from the center hole of the relief pattern surface of the molded substrate to the outer periphery.

[0005]

The above-mentioned "slightly outer peripheral portion from the center hole of the relief pattern surface" means a portion as close as possible to the center hole as far as molding of the annular minute concave portion is possible. Then, an adhesive is annularly applied to the outer peripheral side along the annular minute concave portion, and is spread by spin coating or the like to form a uniform thin adhesive layer over the entire outer peripheral region than the annular concave portion, The two molded substrates superimposed on each other are bonded by this adhesive layer. At this time, the inner peripheral end of the adhesive layer is located near the center hole of the molded substrate, and further extends radially inward in the bonding step, but the radially inward extension is prevented by the annular concave portion. Therefore, it is reliably prevented that this protrudes into the inner peripheral surface of the center hole. Therefore, the inner peripheral edge of the adhesive layer can be made as close as possible to the inner peripheral surface of the center hole while preventing the adhesive from protruding. Therefore, biting and catching of the sliding protrusion member 3 on the bonding surface of the molded substrate are significantly reduced.

[0006]

[Embodiment 1] Embodiment 1 is that the inner diameter of the annular minute recess is 1.5 to 2 mm larger than the diameter of the center hole.

By making the inner diameter of the annular minute recess larger by 1.5 to 2 mm than the diameter of the center hole, there is no problem in forming the annular minute recess, and the annular minute recess can be formed. The influence on the inner peripheral portion of the molded substrate due to the above can be suppressed as much as possible. Therefore, the inner diameter of the adhesive layer can be made as close as possible to the inner peripheral surface of the center hole.

[0007]

[Embodiment 2] Embodiment 2 is that the width of the annular minute concave portion is set to 4.0 to 5.0 mm.

The width of the annular minute concave portion is 4.0 to 5.0 mm.
By doing so, the workability of manufacturing the stamper (original mold) is not unreasonable, so that the molding accuracy of the annular minute concave portion can be ensured, and the required damming effect on the adhesive layer by the annular minute concave portion is obtained. Can be secured.

[0008]

Embodiment 3 In Embodiment 3, the inclination angle of the inner peripheral edge of the annular minute concave portion with respect to the horizontal is 2.0 to 5.0 deg, and the inclination angle of the outer peripheral edge with respect to the horizontal is 1.5.
To 3.0 deg.

The size of the inclination angle of the inner peripheral edge of the annular minute concave portion with respect to the horizontal determines the efficiency of introduction of the adhesive into the annular minute concave portion, and the magnitude of the inclination angle of the outer peripheral edge of the annular minute concave portion with respect to the horizontal direction is the adhesive formed by the annular minute concave portion. The effect of the damming is affected. And from this, by making the inclination angle of the inner peripheral edge of the annular minute concave portion to the horizontal larger than the inclination angle of the outer peripheral edge to the horizontal, the adhesive is efficiently introduced into the annular minute concave portion,
In addition, the effect of blocking the adhesive by the annular minute concave portion can be sufficiently ensured. By setting the inclination angle of the outer peripheral edge of the annular minute concave portion to be in a range of 1.5 to 3.0 deg, the adhesive is efficiently introduced into the annular minute concave portion, and the adhesive is reliably and sufficiently applied to the annular minute concave portion. It can be interposed in the recess. Further, by setting the inclination angle of the other inner peripheral edge to 4.0 to 5.0 deg, the adhesive introduced into the annular minute concave portion is reliably blocked at the inner peripheral edge, and the adhesive is applied to the inner periphery of the center hole. It can be reliably prevented from protruding. Although the inclination angle of the outer peripheral edge affects the efficiency of introducing the adhesive into the annular minute concave portion, it does not directly affect the blocking function for preventing the adhesive from protruding into the center hole. Even if the range slightly deviates from the above 1.5 to 3.0 deg, there is no practical problem.

The above is a solution to the main problem and its operation,
As an embodiment, the means for solving the problem relating to the stamper and its operation, and the means for solving the problem regarding the method of manufacturing the stamper and its operation for realizing this solution are as follows.

[0010]

[Solution Means for Stamper] A solution for the stamper is to provide a stamper having a predetermined relief pattern to be transferred to the above-mentioned molded substrate by providing an annular minute convex portion on a slightly outer peripheral portion of an inner diameter portion fitted with a mold member. That is.

[0011]

When the substrate is injection-molded using this stamper, the above-mentioned annular minute convex portion is transferred and an annular minute concave portion is formed at a predetermined position, so that the position and shape of the minute concave portion can be determined with high precision. Can be formed.

[0012]

[Solution Means for Stamper Manufacturing Method] The solution means for the stamper manufacturing method is that, in the step of manufacturing a stamper used for molding an optical disc substrate, an annular minute convex portion corresponding to the annular minute concave portion formed on the substrate surface is formed. The formed donut-shaped member with minute projections is produced, and the member with minute projections is fixed on a glass master disc that has been exposed.

[0013]

If the annular convex portion is provided in advance on the glass master, there is a problem in applying a uniform thickness of the photosensitive agent for forming the relief pattern (the allowable range of the thickness variation is several tens angstroms or less). It is impossible as a practical problem to provide a ring-shaped convex portion in advance on the glass master disk, since it causes a problem in strict photosensitive agent application management. As described above, the portion provided with the ring-shaped microprojections is formed in a processing step separate from the processing step of the relief pattern, so that the processing step of the relief pattern is not affected, and the processing of the ring-shaped microprojections is performed by a dedicated processing apparatus. Can be performed efficiently.
Also, in the step of electroforming the stamper from the glass master, the annular recess is formed on the stamper together with the relief pattern, so that the position and shape of the minute recess can be formed with extremely high precision.

[0014]

Embodiment 1 Embodiment 1 is that the member with minute projections is fixed to the glass master by adhesive bonding.

In the stamper forming step using the glass master, a mechanical load is hardly applied to the fixing portion of the member with minute projections to the glass master, and the work of fixing the member with minute projections to the glass master is small. Since the alignment of the microprojection member with the glass master is not required to be so strict, there is no problem in fixing the adhesive by adhesive fixing. Since the fixing operation can be performed easily and quickly, the operation cost can be reduced.

[0015]

[Embodiment 2] Embodiment 2 is that the material of the member with minute projections is made of nickel metal.

The glass master after the exposure step is almost in contact with nickel metal until the step of forming a stamper for injection molding of a molding substrate. Therefore, the material of the member with minute projections is nickel metal. As a result, the same compatible metal is used.

[0016]

[Embodiment 3] Embodiment 3 is that the thickness of the member with minute projections is 30 to 50 μm.

The thickness of the member with minute projections is 30 to 50 μm.
When the two molded substrates are superimposed,
The minimum height required for sufficiently performing the blocking function of the adhesive can be secured. If the thickness is more than this (for example, 100 μm), the quality of the molded substrate such as poor appearance of the molded substrate (cold slag or defective deflection) is hindered. Inconveniences are avoided.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. An embodiment of the molded substrate is shown in FIG. 3, but the information surface of the molded substrate 10 on which the unevenness necessary for recording and reproducing information is formed is microscopically shown in FIG. As can be seen, the outer peripheral portion is slightly outer peripheral portion of the inner diameter portion (specifically, 1.5 mm to 2 mm radially outward in the center hole space.
5 m m radially outward) to the annular minute recesses 11 (the groove width is specifically 4.5 to 5.0 mm. 4.5 mm in this example)
Is provided. The shape is trapezoidal, with a maximum depth of 30μ
m, the width is 5 mm from the beginning to the end of the inclined portion.
As shown in FIG. 4B, the trapezoidal shape has an inner peripheral edge inclination angle 傾斜 i of 2.0 to 5.0 deg (Θi: 2.0 deg in this example) and an outer peripheral edge inclination angle Θo of 1.5 to 3.0 deg (Θo: 3.0 in this example).
0 deg). The annular concave portion 11 formed on the molded substrate 10 is formed by a minute convex portion 11a provided on an inner peripheral portion of a stamper 12 placed in a mold.

The stamper manufacturing process in this embodiment is based on the following procedure. As usual, a photosensitive agent is applied to the optically polished glass master 20, and a predetermined pattern is exposed and formed by a laser beam or the like. Thereafter, a predetermined relief pattern is formed through a development step and the like. Then, the attachment member 21 provided with the annular minute projection 11b is separately manufactured in advance, and the center of a predetermined relief pattern (generally, a spiral shape) formed in the exposure step and the minute attachment member 21 are formed. Are adhered and fixed in a state where the centers are aligned (FIG. 5). In addition, the above-mentioned member 2 with minute projections
No. 1 is produced by pressing metal.

The member 21 with fine projections is made of Ni metal and has a thickness of about 40 μm. In the early stage of the invention, a method was adopted in which a glass master having annular protrusions having the above-mentioned shape was adopted, a photosensitive agent was applied thereto, and a predetermined pattern was exposed and formed by a laser beam or the like. In this case, it was confirmed that there was a problem in making the coating thickness of the photosensitive agent required to control the film thickness in angstrom units due to the annular protrusion becoming an obstacle, so that a separate process was performed as described above. A method of producing an annular projection member and assembling it with a glass master having been subjected to exposure and integrating it with the glass master has been adopted, thereby irrespective of the above-mentioned problem, the glass to be subjected to stamper molding having an intended annular projection. The master could be produced.

Further, the shape of the member with the annular projection is determined for the following reasons. That is, in the initial stage of creation of the present invention, the shape of the annular concave portion, ie, the annular convex portion on the stamper, is a trapezoid whose rising (radially inner inclined surface) and falling (radially outer inclined surface) inclination angles are almost equal. Or it had an arc shape. However, when the substrate was molded with a stamper with a certain inclination angle,
The function of suppressing (stopping) the flow of the adhesive, which is the original purpose, was not sufficiently achieved. For this reason, when the inclination angle is steep, the function of suppressing the flow of the adhesive is exhibited as expected,
Some molding defects occurred during substrate molding. That is, "cold slug" or "defective polarization". In order to achieve both the prevention of molding failure and the suppression of the flow of the adhesive, the relationship between the rising and falling inclination angles of the annular concave shape is defined as "inner peripheral inclination angle> outer peripheral inclination angle" (FIG. 4 (a)). (B)), it is confirmed that the flow of the adhesive can be more reliably suppressed by increasing the inclination angle Θi on the inner peripheral side of the annular recess in the above range based on this finding. What is necessary is just to set the inclination angle Θo on the outer peripheral side of the annular concave portion to an obtuse angle. In this example, it was confirmed that the intended function was achieved by setting the angle as described above.

Next, the depth of the annular concave portion of the substrate, that is, the height of the annular convex portion on the stamper is determined for the following reason.
At the beginning of the invention, the thickness was set at about 100 μm in order to more reliably control the flow of the adhesive. However, at about 100 μm, the height of the annular convex portion was too high, and the product was completed. There is a problem in the flatness of the stamper, and further, it has an adverse effect on the birefringence characteristics of the molded substrate. As a result of performing a trial in a direction in which the height of the annular convex portion is reduced in order to solve this problem, it has been confirmed that the above problem is eliminated if the height is reduced to 50 μm or less at the maximum. Note that this is for the case where the shape of the annular projection is trapezoidal, but it is necessary to make the same dimensional relationship also for the case where the shape is circular. On the other hand, in order to ensure the desired function of the micro annular concave portion of the molded substrate, the width is at least 4.0 mm.
Is necessary. In consideration of the above, various dimensional relationships in actual implementation may be appropriately determined.

The glass master 20 is provided with a member 2 with an annular projection.
After fixing and integrating the same, the intermediate replication member 22 is formed as shown in FIG. 6A in the steps of conductive film formation, electroforming, etc. in the same manner as in a normal stamper manufacturing step. 6
As shown in (b), the stamper 12 is formed using the intermediate duplication member. Then, the stamper 12 is placed in a mold and the substrate is molded, whereby the molded substrate 10 having a predetermined annular concave portion is obtained. The lamination type optical information recording medium formed by laminating the two sheets has a cross-sectional shape as shown in FIG. 7, and since the adhesive layer has reached very close to the center hole, the same optical information recording medium is obtained. The sliding projection member 4 does not bite into the inner peripheral end of the joining surface of the recording medium. Therefore, even if the optical information recording medium is repeatedly attached and detached, the sliding projection member 4 is caught and the optical information recording is performed. The inner peripheral edge of the medium is not damaged.

[0023]

The effects of the present invention described above are summarized below for each of the main claims. [Effect of the invention according to claim 1] For a laminated optical information recording medium of a molded substrate having a flat lamination surface (information surface) side, it is possible to effectively suppress the flow of the adhesive and not to affect the inner diameter portion. Can be matched. Therefore, when the optical information recording medium is mounted on a drive device of a portable information terminal device and used, there is no possibility that the inner peripheral portion of the optical information recording medium is damaged by the holding device, and high reproduction accuracy is achieved. Can be used safely while maintaining.

[Effect of the invention according to claim 6] An annular convex portion for forming an annular minute concave portion for suppressing the flow of the adhesive is formed on the stamper in a stamper duplication step, and the annular minute concave portion is formed by using this stamper. Since the molded substrate having the concave portion can be molded, the molded substrate according to claim 1 can be molded with high accuracy and efficiency.

According to the seventh aspect of the invention, an annular projection is provided on a glass master to form the annular minute projection on a stamper, and an intermediate replica member having an annular minute recess is formed using the glass master. Further, since the stamper is duplicated by using the stamper, the stamper according to claim 6 can be molded with high accuracy and efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a mounted state of an optical information recording medium in a portable optical information recording medium reproducing apparatus.

FIGS. 2A and 2B are cross-sectional views schematically showing problems of the related art.

FIG. 3 is a schematic perspective view of a molded substrate according to an embodiment of the present invention.

4A is an enlarged sectional view of a portion A in FIG.
FIG. 4B is an enlarged view of a main part of FIG.

FIG. 5 is a perspective view of a glass master for forming a stamper according to an embodiment of the present invention.

6A is a cross-sectional view schematically showing a replication process of an intermediate replication member using the glass master of FIG. 5, and FIG. 6B is a stamper replication using the intermediate replication member of FIG. 6A. It is sectional drawing which shows a process typically.

FIG. 7 is a sectional view of a laminated optical information recording medium according to the present invention.

[Explanation of symbols]

 1: optical information recording medium 2: center axis of a turntable of a portable reproducing apparatus 3: sliding projection member 10: molded substrate 11: minute annular concave portion 11a: minute annular convex portion of a stamper 11b: annular minute projection portion of a glass master 20: Glass master 21: Member with annular minute projection T: Turntable

Claims (12)

[Claims] 1. A molded substrate for an optical information recording medium, comprising two substrates bonded together to form one recording medium, on a surface having a relief pattern provided for recording and reproducing information. In a molded substrate having a flat surface that does not leave a trace of the stamper holding member that becomes the base of the relief pattern in the mold, an annular minute recess is formed slightly from the center hole of the relief pattern surface of the molded substrate to the outer periphery. A molded substrate for a laminated optical information recording medium, wherein the molded substrate is provided. 2. The molded substrate for a laminated optical information recording medium according to claim 1, wherein the inner diameter of the annular minute concave portion is larger by 1.5 to 2 mm than the diameter of the center hole. 3. The width of the annular minute concave portion is 4.0 to 5.0.
2. The molded substrate for a laminated optical information recording medium according to claim 1, wherein the thickness is in mm. 4. The method according to claim 1, wherein the cross-sectional shape of the annular minute concave portion formed on the surface of the molded substrate is substantially trapezoidal or arcuate, and the inclination angle with respect to the horizontal direction has a relationship of “inner side> outer side”. The molded substrate according to claim 1, characterized in that: 5. The inclination angle of the inner peripheral edge of the annular minute concave portion with respect to the horizontal is 2.0 to 5.0 deg, and the inclination angle of the outer peripheral edge with respect to the horizontal is 1.5 to 3.0 deg.
The molded substrate for a laminated optical information recording medium according to claim 4. 6. A stamper having a predetermined relief pattern to be transferred to a molded substrate, characterized in that the stamper has an annular minute convex portion at a slightly outer peripheral portion of an inner diameter portion fitted with a mold member. A stamper for forming a molded substrate. 7. In a step of manufacturing a stamper used for molding an optical disk substrate, a donut-shaped member with minute projections having an annular minute convex portion corresponding to the annular minute concave portion formed on the substrate surface is produced. The member with minute projections,
7. The stamper manufacturing method for manufacturing a stamper according to claim 6, wherein an original master fixed on a glass master that has been exposed is used. 8. The stamper manufacturing method according to claim 7, wherein the fixing of the member with minute projections to the glass master is performed by adhesive bonding. 9. The stamper manufacturing method according to claim 7, wherein a material of said member with minute projections is nickel metal. 10. The thickness of the member with minute projections is 30 to 5
The method for producing a stamper according to claim 7, wherein the thickness is 0 μm. 11. The method according to claim 1, wherein the cross-sectional shape of the annular minute concave portion formed on the surface of the molded substrate is substantially trapezoidal or arcuate, and the height in the vertical direction is “less than 50 μm”. Molded substrate. 12. A laminated optical information recording medium wherein two molded substrates according to claim 1 formed by using the stamper according to claim 6 produced by the production method according to claim 7.