JP2002342977A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-density optical disk which is prevented from the intrusion of rubbing flaws into substrate surface, a light transparent sheet and a label layer in temporarily storing substrate during the course of a manufacturing process and completed optical disk. SOLUTION: The optical information recording medium 50 which has a reflecting film 4 deposited on an information signal surface 2 formed on a substrate 1 and is provided with light transparent sheet 9 thinner than the substrate 1 with a light transparent adhesive 11 in the upper part of the reflecting film 4 is provided with a stack rib 3 on the information signal 2 surface side of the substrate 1. The height of the stack rib 3 when the light transparent sheet 9 having a hold diameter grater than the central hole 27 of the substrate 1 is disposed on the side outer than the external diameter side of the stack rib 3 is set higher by at least 0.08 to 0.5 mm than the sum of the thickness of the light transparent sheet 9 and the thickness of the adhesive 11.

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 more particularly, to an optical information recording medium (hereinafter referred to as an optical disk) capable of increasing the recording density by reducing the thickness of a substrate on the reading surface side on which laser light is incident. ).

[0002]

2. Description of the Related Art In recent years, optical discs have been developed for high density, large capacity and small size. Higher density can be achieved by shortening the wavelength of the laser light or increasing the numerical aperture of the objective lens for irradiating light during recording and reproduction of the optical pickup to reduce the spot diameter of the recording and reproduction light. It is possible. As described above, when the numerical aperture of the objective lens is increased, it is necessary to reduce the thickness of the substrate on the incident surface side of the optical disc through which the reproduction light is irradiated and through which the reproduction light passes. This is because the allowable amount of the angle (tilt angle) at which the disk surface deviates from the perpendicular to the optical axis of the optical pickup becomes small, and this tilt angle is easily affected by aberration and birefringence due to the thickness of the substrate. That's why. Therefore, the next-generation optical disk is designed to reduce the tilt angle as much as possible by reducing the thickness of the substrate.

For example, a CD has a substrate thickness of about 1.2 mm on the incident surface side, whereas a DVD having a recording capacity of 6 to 8 times the CD has a thickness of about 0.6 mm, which is half of that of a CD. Is the thickness. Recently, there has been a demand that the recording capacity per disc of the same size as a CD or DVD be increased to a large recording capacity of 15 GB or more. In this case, as an example, the thickness of the substrate on the incident surface side is as follows. DVD mentioned above
Is about 0.3 mm, which is half of the above. If the thickness on the incident surface side is about 0.1 mm, the recording capacity is 20 GB.
Since it is difficult to manufacture such a disk having a high recording capacity by a conventional injection molding method because the substrate is too thin, some other manufacturing methods have been proposed.

[0004] One method is as follows. A substrate containing an information signal is produced by the same injection molding method as in the prior art, a reflective film of aluminum or the like is formed on the information signal surface, and a substrate is formed thereon. A light-transmitting sheet of the same size is bonded with a light-transmitting adhesive by a spin bonding method or the like. Then, the reproduction light is incident on the light transmissive sheet side.

At this time, the outer diameter of the substrate is determined by the CD or D
It is φ120 mm, which is the same as VD, and a thickness of 0.6 mm or more is required to form a substrate of this size by the injection molding method. Therefore, according to the above-described method of the next-generation optical disc, the thickness of the light transmitting sheet provided on the side where the reproduction light is incident is smaller than the thickness of the substrate on which the information signal is formed.

In the manufacturing process of CDs and DVDs, movement and temporary storage between processes are performed by stacking substrates on pins. In this case, the substrate is provided with a ring-shaped convex rib-shaped stack rib so that the signal surface and the incident surface layer of the substrate do not come into contact with each other and are not damaged by rubbing.
Further, a label layer on which a title or the like is written is provided on the surface opposite to the surface on which the stack ribs are provided, and this surface is flat so that label production by screen printing or the like can be performed well.

This point will be described in detail with reference to FIG. FIG. 10 shows a CD form in which an information signal 2 formed by injection molding on a substrate 1 and a stack rib 3 formed on the opposite side of the information signal 2 are provided on the information signal 2 surface of the substrate 1. The optical disk 10 is obtained by forming a metal reflective film 4 by sputtering or the like, forming a protective film 5 of UV resin or the like thereon, and further forming a label layer 6 thereon by screen printing or the like. .

FIG. 11 shows a DVD format, in which the substrate 1
A metal reflection film 4 is formed by sputtering or the like on the information signal 2 of the substrate 1 on which the information signal 2 formed by injection molding and the stack rib 3 on the side opposite to the information signal 2 are formed. .

Then, a dummy substrate 7 serving as a dummy is manufactured by injection molding, and the information signal 2 surface of the substrate 1 is turned inside, and a UV adhesive 8 or the like is interposed between the substrate 1 and the dummy substrate 7. The optical disk 20 is obtained by forming the label layer 6 on the upper surface side of the dummy substrate 7 by screen printing or the like.

FIG. 12 is a conceptual diagram of a further improved DVD. In FIG. 12, an information signal 2 formed by injection molding on a substrate 1 and an information signal 2 surface of the one substrate 1 on which a stack rib 3 is formed inside a surface opposite to the information signal 2 are shown. The translucent film 21 is formed by sputtering or the like.

On the other hand, an information signal 22 formed by injection molding on a substrate 24, and a stack rib 23 formed inside the same surface as the information signal 22 on the information signal 22 surface of the other substrate 24, The reflection film 4 is formed by sputtering or the like, and the information signal surfaces 2 and 22 of these two substrates 1 and 24 are opposed to each other, so that
The optical disc 30 is obtained by forming the label layer 6 on the surface of the other substrate 24 opposite to the information signal 22 after bonding the two with the light-transmitting adhesive 8 interposed between them. Things.

An example of this case is a single-sided, dual-layer DVD.
However, a single-layer DVD can be formed by forming a reflective film instead of the translucent film 21 and using the other substrate 24 as a dummy plate.

[0013]

FIG. 13 is a sectional view showing one form of a next-generation high-density optical disk that has been already proposed. For example, a metal reflective film 4 is formed by sputtering or the like on the information signal 2 surface of the substrate 1 on which the information signal 2 is formed by injection molding, and a light transmitting sheet 9 is formed thereon.
Are bonded by a light transmitting adhesive 11. The optical disc 40 is obtained by forming the label layer 6 on the substrate 1 side since the reproduction light incident surface layer is formed from the light transmitting sheet 9 side.

In such a next-generation high-density optical disk, as described above, when moving between processes or temporarily storing the same, the stack ribs for stacking the substrates are opposite to the surface on which the information signal 2 is formed. As described above, since the label layer 6 is formed thereon, the CD (optical disk 10) shown in FIG.
It was difficult to form the stack rib 3 in the same place as D (optical disk 20).

By the way, the places where the substrates need to be stacked in the manufacturing process are described as follows: places during molding, places before and after lamination, places before and after printing, places before and after inspection, before packing, and movements between each step. And so on.
In FIG. 12, since the stack ribs 3 and 23 are provided on the two substrates 1 and 24, the stack ribs 3 and 23 are stocked in the pins before molding and before bonding, respectively. It is lost because it becomes a bonding surface.

That is, as described above, in the embodiment shown in FIG. 12, the stack ribs 3 and 23 are respectively formed on the substrates 1 and 24, and the other substrate 24 is disposed on the one substrate 1 side.
It is necessary to provide a ring-shaped groove 25 for accommodating the stack ribs 23 provided in the above.

Here, a next-generation high-density optical disk in which two substrates are bonded will be considered. As mentioned above,
Since the next-generation high-density optical disk also employs a form in which two substrates are bonded, the forms shown in FIGS. 11 and 12 are conceivable. However, when the stack ribs 3 are provided on the side opposite to the surface on which the information signal 2 is formed in the form as shown in FIG. 11, the label layer is usually there in the next-generation high-density optical disk. Since it is printed, there is a disadvantage that it cannot be performed.

In the embodiment shown in FIG. 12, the substrate 1 is replaced with a light-transmitting sheet, and a convex portion having a thickness approximately equal to that of the stack rib 3 is formed as a separate component. Although it is possible to achieve the purpose by attaching to the surface, in such a case, the yield is increased due to an increase in the number of processes, and the mounting position is varied due to the attachment, resulting in a disadvantage that the product quality is deteriorated.

Therefore, according to the present invention, a stack rib can be formed on the information signal surface side even in a next-generation high-density optical disk,
It is another object of the present invention to provide an optical disk having a disk form in which the stack rib exerts its original function in each of the steps described above.

In the next-generation high-density optical disc, the working distance (distance between the incident surface layer of the substrate and the pickup lens) is small, and depending on the position and shape of the stack rib, the parts such as the stack rib and the pickup lens may be used during reproduction. It is anticipated that the optical discs may come into contact with each other, thereby causing the pickup lens to be tilted and not being able to be reproduced. Therefore, it is an object of the present invention to provide an optical disc that avoids such a problem by specifying the position and height of the stack rib. .

[0021]

As a means for achieving the above object, a reflective film 4 is formed on the surface of the information signal 2 formed on the substrate 1, and an optically transparent film is formed on the reflective film 4. In an optical information recording medium provided with a light transmitting sheet 9 thinner than the substrate 1 by an adhesive 11, a stack rib 3 is provided on the information signal 2 side of the substrate 1;
The height of the stack ribs 3 when the light transmissive sheet 9 having a larger hole diameter than the center hole 27 is provided outside the outer diameter portion of the stack rib 3 is set to the height of the light transmissive sheet 9. The thickness is set to be at least 0.08 mm to 0.5 mm higher than the sum of the thickness and the thickness of the adhesive 11.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. It should be noted that since the following examples are preferred specific examples of the present invention, various technically preferable limitations are added. However, the scope of the present invention is particularly limited in the following description. Are not limited to these embodiments unless otherwise described.

FIG. 1 is a half sectional view of a first embodiment of a next-generation high-density optical disc according to the present invention, and FIG. 2 is a half sectional view of a second embodiment of the next-generation high-density optical disc according to the present invention. FIG. 3 is a half sectional view of a third embodiment of the next-generation high-density optical disc according to the present invention. FIG. 4 is a fourth embodiment of the next-generation high-density optical disc according to the present invention. FIG. 5 is an explanatory diagram showing the relationship between the condition of the stack ribs and the yield rate, and FIG. 6 is a schematic diagram for manufacturing the next-generation high-density optical disk according to the present invention. FIG. 7 is a schematic view for explaining a method of attaching a light transmitting sheet to a substrate.
8 is a cross-sectional view of the optical disc bonded in FIG.
FIG. 9 is a cross-sectional view of an optical disc formed by a method different from the method of manufacturing a next-generation high-density optical disc according to the present invention.
FIG. 3 is a cross-sectional view of an optical disc formed by a method different from the method of manufacturing a next-generation high-density optical disc according to the present invention.
The same components as those in the related art are denoted by the same reference numerals, and detailed description thereof is omitted.

Hereinafter, a preferred embodiment of a next-generation high-density optical disk according to the present invention will be described with reference to FIGS.

FIG. 1 is a half sectional view of a first preferred embodiment of a next-generation high-density optical disk 50 according to the present invention. In FIG. 1, reference numeral 26 denotes a clamping area for clamping the optical disk 50; , This optical disk 50
Center hole. In the first embodiment, the stack rib 3 formed on the side of the information signal 2 is located outside the clamping area 26 (away from the center hole 27,
(A direction approaching the surface side).

FIG. 2 is a half sectional view of a second preferred embodiment of the next-generation high-density optical disk 60 according to the present invention. In the second embodiment, the stack rib 3 formed on the information signal 2 surface side is
In a relatively wide range.

FIG. 3 is a half sectional view of a third preferred embodiment of the next-generation high-density optical disk 70 according to the present invention. In the third embodiment, a plurality of stack ribs 3 formed on the side of the information signal 2 are formed in the clamping area 26.

FIG. 4 is a half sectional view of a fourth preferred embodiment of the next-generation high-density optical disk 80 according to the present invention. In the fourth embodiment, the stack rib 3 formed on the side of the information signal 2 is formed inside the clamping area 26 (in the direction approaching the center hole 27).

The advantages of the optical disk according to the present invention configured as described above will be described below.

The stack rib 3 of the next-generation high-density optical disk is located at the inner side (center hole 27) of the lead-in signal position (not shown) on the information signal side of the substrate 1 on which the information signal 2 is formed.
Side), and has an inner diameter larger than the center hole 27 of the substrate 1, for example, an annular light-transmitting sheet 9.
To the outside of the outer diameter side of the stack rib 3. The height of this stack rib 3 is
It is necessary to make the thickness higher than the sum of the thickness of the light-transmitting sheet 9 and the thickness of the adhesive 11 so as to function in any step.

The stack rib 3 obtained by various experiments
Has a good range from [the thickness of the light-transmitting sheet 9 + the thickness of the adhesive 11 + 0.08 mm the former] to the [thickness of the light-transmitting sheet 9 + the thickness of the adhesive 11 + 0.5 mm the latter]. The result is that it is. In the former,
The height of the stack rib 3 is [the thickness of the light-transmitting sheet 9 +
If the thickness is lower than the sum of the thickness of the adhesive 11 and 0.08 mm], when the substrates 1 on which the light transmitting sheets 9 are bonded by the adhesive 11 are stacked on stock pins (not shown), the substrates come into contact with each other. This is because scratches occur on the light transmitting sheet 9 and the label layer 6.

Further, [thickness of light-transmitting sheet 9 + adhesive 1
1 + 0.5 mm] or more, the interval when the optical disks are stacked is widened, and the number of optical disks stacked on one stock pin (not shown) is reduced, and the storage efficiency is deteriorated. In addition, the flow of the resin in the molding die changes greatly depending on the shape of the stack ribs 3, so that the quality of the information signal at the innermost circumference of the optical disc is deteriorated.

On the other hand, the light transmitting sheet 9 when bonded
May be provided with a light-transmitting protective sheet (not shown). In some cases, bonding may be performed with the protective sheet (not shown) attached. At this time, the height of the stack rib 3 is The thickness of the light-transmitting sheet 9, the thickness of the adhesive 11, the thickness of the not-shown protective sheet, and the sum of the thickness of the light-transmitting sheet 9 and the not-shown adhesive material that are bonded together and the not-shown adhesive material Experimental results indicate that good results can be obtained.

Further, since the position of the stack rib 3 is stable when the optical discs are stacked, the stack rib 3 is located inside the above-described lead-in signal position (not shown) (on the side of the center hole 27), and
It is preferable to provide it near the lead-in signal position.

However, when the working distance (the distance between the incident surface layer of the substrate and the pickup lens) is 0.
There is also a proposal for a next-generation high-density optical disk of about 1 mm,
In this case, if the stack rib 3 is too close to the lead-in signal position (not shown), the stack rib 3 contacts the pickup lens (not shown) and its components, and the pickup lens (not shown) cannot tilt and reproduce. Since a problem occurs, it is necessary to consider that point.

The size of the pickup lens in the current DVD player or the like is generally about 4.6 mm, and the outer diameter of the holder for holding the lens is about 5.6 mm in consideration of the allowance. The distance between the outer diameter of No. 3 and the maximum diameter of the lead-in signal position needs to be larger than the distance of about 2.8 mm from the arrangement of the respective components.

In a commercially available CD player or DVD player, a system in which a pickup lens is incorporated in an actuator is employed, and there is a high possibility that the same system will be employed when mass-producing a next-generation high-density optical disk player.
In this case, the size of the current actuator is more than 10 mm
Since it has a rectangular shape, it is necessary to further open the space between the outer diameter of the stack rib 3 and the lead-in signal position.

Further, in the area inside the lead-in signal position, there is a clamping area 26 area.
When the distance between the outer diameter of the stack rib 3 and the maximum diameter of the lead-in signal position is about 2.8 mm, the stack rib 3 can be formed outside the clamping area 26 as shown in FIG.

Further, the CD player and DVD player described above stipulate that the surface of the clamping area 26 and the surface of the information signal area are flat, but this is compatible with the drive of each company and the disc of each company. In a next-generation high-density optical disk, this may be the same, or if compatibility is obtained, all or one of the clamping areas 26 as shown in FIGS. The portion may be a stack rib 3.

The stack ribs 3 may be located inside the inner circumference of the clamping area 26 (center hole 27 side) as shown in FIG. In this case, since the substrates 1 become unstable when they are stacked, it is necessary to take measures such as increasing the height of the stack ribs 3 so that the substrates do not contact each other. In any case, it is best that the inner diameter of the light-transmitting sheet 9 is in the range from the outer diameter of the stack rib 3 to the lead-in signal position (the inner diameter of the light-transmitting sheet 9 is larger than the lead-in signal position). In this case, the signal in the signal area cannot be read and thus cannot be reproduced. When the diameter is smaller than the outer diameter of the stack rib 3, the light transmitting sheet 9 is distorted. Because it becomes bigger).

At this time, the inner diameter of the light transmitting sheet 9 and the outer diameter of the stack rib 3 do not need to be in contact with each other, and may have a gap. Furthermore, the corners of the stack ribs 3 may be formed perpendicular to the substrate surface, but if the angles are set to be dull, the flow of the resin and the releasability at the time of molding will be improved. desirable.

By the way, as described in the above-mentioned conventional technique, for example, when a capacity of 15 GB is obtained, the substrate thickness is about 0.3 mm, and it is difficult to form this by the conventional injection molding method. It is. Further, when considering the total thickness of the high-density optical disk, it is easy to manage the thickness of 1.2 mm which is the same as that of a CD or DVD from the viewpoint of handling. Therefore, as one form of a next-generation high-density optical disc, for example, 15 GB
In order to obtain a capacity of 0.3 mm, the thickness of the incident surface layer is 0.3 mm
Assuming that, after a substrate having a 0.9 mm-thick information signal is formed by injection molding or the like, a reflective film is formed on the information signal surface, and a light-transmitting sheet is further formed thereon. A method in which the light is incident on the light-transmitting sheet from the light-transmitting sheet side is considered.

When the density of the light transmitting sheet 9 is reduced to 0.1 mm as the density is further increased, the substrate containing the information signal is 1.1 mm. That is, the thickness of the light transmissive sheet 9 is considerably smaller than that of the substrate containing the information signal. In this case, the combination of the incident surface layer is 0.1 mm and the substrate thickness is 1.1 mm, but the present invention is not limited to this.

Further, in this embodiment, a read-only type (RO
(M type), but the present invention is not limited to this, and it is needless to say that the present invention can be applied to a write-once type, a rewritable type, and a magneto-optical disk.

Embodiment 1 Hereinafter, a specific embodiment of the present invention will be described in more detail. As described above with reference to FIG. 1, the outside of the clamping area 26 (φ3
At a position of 4 mm to 36 mm), the stack rib 3 was formed to have a height of 0.23 mm and a tapered shape on the information signal 2 surface side.

Embodiment 2 A stack rib 3 having the same shape and a height of only 0.19 mm was formed on the information signal 2 surface side at the same position as in the above-described embodiment 1.

(Embodiment 3) Next, as described with reference to FIGS. 2 and 3 described above, the stack is placed on the information signal 2 side at the same position (φ22 mm to φ33 mm) as the clamping area 26. The rib 3 was formed to have a height of 0.23 mm and a tapered shape.

(Example 4) A stack rib 3 having the same shape and a height of only 0.19 mm was formed on the information signal 2 side at the same position as in Example 3 described above.

(Embodiment 5) Next, as described above with reference to FIG.
19mm ~ φ21mm) on the information signal 2 surface side,
The stack rib 3 was formed to have a height of 0.27 mm and a tapered shape.

(Embodiment 6) A stack rib 3 having the same shape and a height of only 0.23 mm was formed on the information signal 2 surface side at the same position as in the above-described Embodiment 5.

(Comparative Example 1) As described in the first embodiment, the outer side of the clamping area 26 (φ3
At a position of 4 mm to 36 mm, the stack rib 3 was formed to have a height of 0.15 mm and a tapered shape on the information signal 2 surface side.

(Comparative Example 2) As described in Embodiments 3 and 4, the stack rib 3 is provided on the information signal 2 surface side at the same position (φ22 mm to φ33 mm) as the clamping area 26. It was formed as a tapered shape with a height of 0.15 mm.

Comparative Example 3 Examples 5 and 6 described above.
As described above, the information signal 2 is located at a position (φ19 mm to φ21 mm) inside the clamping area 26.
On the surface side, the stack rib 3 was formed in a tapered shape with a height of 0.19 mm and tapered.

(Comparative Example 4) At the same position as that of Comparative Example 3 described above, the stack rib 3 having the same shape was placed on the information signal 2 surface side.
Was formed such that only its height was 0.15 mm.

In the above Examples and Comparative Examples, the disk substrate 1 in which the height and the position of the stack ribs 3 were changed was formed by injection molding, and the thickness of the adhesive 11 was changed using a light-transmitting sheet 9 having a thickness of 0.1 mm. Under a spin coating condition of 0.01 mm, the optical discs 50 and the like completed by bonding the light transmissive sheet 9 to each disc substrate 1 are stacked on stock pins (not shown), and the light transmissivity when 100 discs are stacked The sheet 9 and the surface of the substrate were examined for scratches. The result is shown in FIG.

As is apparent from FIG. 5, in the case of the first to fourth embodiments in which the stack rib 3 is located at the same position as or outside the clamping area 26, if the height of the stack rib is 0.19 mm or more, It can be seen that good results were obtained without scratches on the substrate.

On the other hand, as in Comparative Examples 1 and 2, when the height of the stack ribs is as low as 0.15 mm, it can be seen that a scratched substrate is generated.

In the case of the fifth and sixth embodiments in which the stack ribs 3 are located inside the clamping area 26, if the height of the stack ribs 3 is 0.23 mm or more, the substrate is not scratched and good results are obtained. It turns out that it has been obtained.

On the other hand, when the height of the stack rib 3 is lower than 0.23 mm as in Comparative Examples 3 and 4, it can be seen that a scratched substrate is generated. still,
The test method and test conditions will be described below.

First, a mold having the above-mentioned groove for stutter crib formed inside a lead-in signal position on a stamper surface side (not shown) is attached to an injection molding machine, and then an optical disk grade polycarbonate melted at a cylinder temperature of 380 ° C. The resin was injected into the cavity of the same mold (mold setting temperature: 115 ° C.), and the polycarbonate resin was cured by cooling to produce a substrate.

Then, a reflective film of aluminum is formed on the information signal surface of the substrate manufactured by injection molding by sputtering, and a light-transmitting sheet is bonded thereon with a light-transmitting adhesive. This completes the next-generation high-density optical disk.

The inner diameter of the light transmitting sheet is as shown in FIGS.
Regardless of the position of the stack rib 3 as shown in FIG. 4, the stack rib 3 can be set to any size within the range of the lead-in signal position from the outer diameter of the stack rib 3. As an example, the stack rib 3 is φ34 mm to φ3
With reference to FIG. 6, a method of bonding the light-transmitting sheet 9 with the substrate at a position of 6 mm will be described.

FIG. 6 is a schematic diagram for explaining a process of bonding the substrate 1 and the light transmitting sheet 9. Note that, for convenience of explanation, the information signal 2, the reflection film 4, and the like are not shown in FIG. First, the outer diameter φ1 is determined by the method described above.
20mm, inner diameter (center diameter) φ15mm, thickness 1.1m
Substrate 1 containing m information signals 2 and stack ribs 3 was prepared. Thereafter, an aluminum reflective film having a thickness of 60 nm was formed on the information signal surface by sputtering. The substrate 1 is placed on a center pin 13 provided at the center of a turntable 12 shown in FIG.
Is mounted thereon as a guide, and the substrate 1 is fixed on the turntable 12 by vacuum suction (not shown).

Next, a guide sleeve 14 is mounted on the substrate 1 from above using the center pin 13 as a guide, and the turntable 12 is rotated at a low speed (60 rpm) by a nozzle 15 on a reflection film (not shown). The turntable 12 is rotated and the UV-curable adhesive 16 is applied to the reflective film 4 while the UV-curable adhesive 16 having a light transmissive property is dropped on the circumference of the reflective film 4. The supply is stopped (see FIG. 6A).

Here, the outer diameter φ11 prepared in a separate process in advance
A light-transmitting sheet 9 having a diameter of 9 mm, an inner diameter of 38 mm, and a thickness of 0.1 mm is placed on the substrate 1 using the guide sleeve 14 as a guide, and after the ultraviolet-curable adhesive 16 is stretched, the turntable 12 is rotated at a high speed ( 3000 in the embodiment
rpm) Excessive ultraviolet curable adhesive 16 and air bubbles are removed (see FIG. 6B).

After that, the rotation of the turntable 12 is stopped, and the integrated substrate 1 and the light-transmitting sheet 9 are moved onto the turntable 18 of the ultraviolet irradiation device 17 via the ultraviolet-curable adhesive 16. By irradiating ultraviolet rays from the light transmitting sheet 9 side while rotating the turntable 18 at a low speed to cure the ultraviolet curing adhesive 16, the substrate 1 and the light transmitting sheet 9 are bonded together (FIG. 6).
(C)).

A title or the like is printed by screen printing on the surface of the substrate 1 opposite to the surface on which the light transmitting sheet 9 is adhered to form a label layer 6, and a next-generation high-density optical disk 90 shown in FIG. I got

As described above, the height of the stack rib 3 is set to [the thickness of the light-transmitting sheet + the thickness of the adhesive + 0.08 m
m] or more, even if the substrate on which the light-transmitting sheet 9 is bonded or the optical disk after printing is stacked on stock pins (not shown), the light-transmitting sheet 9
The surface and the label layer 6 have no scratches due to contact. In addition, the height of the stack ribs 3 provided inside the clamping area 26 is [light transmissive sheet thickness + adhesive thickness + 0.12 mm] or more, so that a good result can be obtained. It is.

As a form of a high-density optical disk other than the above, as shown in FIG.
(Ultraviolet curable resin: Photo Polymeriza
information signal 2 is formed by a molding method, and a reflective film 4 (for a reproduction-only type) is formed on the information signal 2 by sputtering or the like. The optical disc 100 in the form of being bonded to the
A first information signal 22 is formed on the light-transmitting sheet 9 by a 2P molding method as described above, and a semi-transparent film 21 (for a reproduction-only type) is formed on the first information signal 22 by sputtering or the like. On the other hand, in a separate step, a second information signal 2 is formed by an injection molding method or the like, and a reflective film 4 (for a read-only type) is formed on the second information signal 2 by sputtering or the like. There is an optical disk 110 of a two-layer type in which the signal surfaces of the optical disks are opposed to each other, and it goes without saying that the present invention is also applicable to a high-density optical disk of these types.

[0070]

As described above in detail, according to the present invention, a reflective film is formed on an information signal surface formed on a substrate, and the reflective film is thinner than the substrate by a light transmitting adhesive on the reflective film. In an optical information recording medium provided with a light transmitting sheet,
A stack rib is provided on the information signal side of the substrate, and the stack rib is provided when the light-transmitting sheet having a larger hole diameter than a center hole of the substrate is provided outside an outer diameter portion of the stack rib. Is at least 0.08 m from the sum of the thickness of the light transmitting sheet and the thickness of the adhesive.
By setting the height higher by m to 0.5 mm, scratches may occur on the substrate surface, light-transmitting sheet and label layer even when the substrate during the manufacturing process or the completed optical disk is stacked on stock pins and temporarily stored. It is possible to provide a good high-density optical disk without any problem.

[Brief description of the drawings]

FIG. 1 shows a first example of a next-generation high-density optical disk according to the present invention.
It is a half sectional view of an example.

FIG. 2 shows a second example of a next-generation high-density optical disk according to the present invention.
It is a half sectional view of an example.

FIG. 3 shows a third example of the next-generation high-density optical disk according to the present invention.
It is a half sectional view of an example.

FIG. 4 shows a fourth example of the next-generation high-density optical disk according to the present invention.
It is a half sectional view of an example.

FIG. 5 is an explanatory diagram showing the relationship between stack rib conditions and non-defective products.

FIG. 6 is a schematic diagram for manufacturing a next-generation high-density optical disk according to the present invention, and particularly a schematic diagram for explaining a method of bonding a substrate and a light-transmitting sheet.

FIG. 7 is a cross-sectional view of the optical disc bonded in FIG.

FIG. 8 is a cross-sectional view of an optical disc formed by a method different from the method of manufacturing a next-generation high-density optical disc according to the present invention.

FIG. 9 is a cross-sectional view of an optical disk formed by a method different from the method of manufacturing a next-generation high-density optical disk according to the present invention.

FIG. 10 is a cross-sectional view of a CD manufactured by a conventional manufacturing method.

FIG. 11 is a cross-sectional view of a DVD manufactured by a conventional manufacturing method.

FIG. 12 is a conceptual diagram as an improved form of FIG. 11;

FIG. 13 is a cross-sectional view showing one form of a next-generation high-density optical disk that has already been proposed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Information signal 3 Stack rib 4 Reflection film 5 Protective film 6 Label layer 7 Dummy substrate 8 UV adhesive 9 Light transmissive sheet 10, 20, 30, 40 Optical information recording medium 11 Light transmissive adhesive 12 Turntable 13 Center pin 22 Information signal 23 Stack rib 24 Substrate 26 Clamping area 27 Center hole 50, 60, 70, 80, 90, 100, 110 Optical information recording medium

Claims (1)

[Claims] 1. An optical information apparatus comprising: a reflective film formed on an information signal surface formed on a substrate; and a light transmitting sheet thinner than the substrate provided on the reflective film by a light transmitting adhesive. In the recording medium, a stack rib is provided on the information signal side of the substrate, and the light-transmitting sheet having a hole diameter larger than a center hole of the substrate is provided outside an outer diameter portion of the stack rib. An optical information recording medium, wherein the height of the stack ribs is set at least 0.08 mm to 0.5 mm higher than the sum of the thickness of the light transmissive sheet and the thickness of the adhesive.