JP3375478B2 - Optical information medium and method for manufacturing optical information medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information medium having two optical information substrates attached to each other, a manufacturing method thereof, and a manufacturing apparatus.

[0002]

2. Description of the Related Art In order to increase the density of optical discs, it is necessary to shorten the wavelength of the reproducing laser and increase the numerical aperture (NA) of the objective lens. However, with a high NA objective lens, the allowable disc tilt is very small. For example, if the same 1.2 mm thick substrate as the CD is used, N
The tilt that can be allowed for an A0.6 objective lens is about 0.25.
This is equivalent to an error in mounting the optical head on the player, and tilt due to the change in shape of the optical disc becomes unacceptable, which is not practical.

By reducing the thickness of the substrate, the allowable range for the tilt of the disk is widened, and a high density of a practical optical disk using a high NA objective lens can be achieved. For example, if the thickness of the substrate is 0.6 mm, which is half of CD, N
The allowable tilt for an A0.6 objective lens is about 0.75
Even if the optical head mounting error is set to 0.25 degree, the tilt due to the actual disc shape change has a margin of up to 0.5 degree.

In the case of an optical disk having a thin substrate, a single plate hangs down by its own weight, and therefore two substrates are bonded together. The capacity is doubled not only by increasing the mechanical strength, but also by using both sides.

FIG. 1 shows a general cross-sectional view of a disk laminated with a radiation curable resin. 1 is the first substrate,
The information signal surface 2 is provided on one surface thereof. On the information signal surface 2, a reflective film 3 such as a metal containing aluminum as a main component is formed. Further, 4 is a second substrate, on one side of which an information signal surface 5 is provided. A reflective film 6 is similarly formed on the information signal surface 5. A radiation curable resin layer 7 is provided between the reflective film 3 and the reflective film 6 facing each other to integrally bond the first and second substrates.

A conventional method of manufacturing this disk will be described with reference to FIG. 2 (Japanese Patent Application No. 6-238846). A substrate 1 having a first information signal surface provided on one surface thereof using a transparent resin such as polycarbonate is manufactured by an injection molding method or the like.
A reflective film is formed on the information signal surface by a sputtering method or a vacuum evaporation method. Further, the substrate 4 having the second information signal surface provided on one surface is formed by injection molding or the like, and the reflection film is formed thereon by the sputtering method or the vacuum evaporation method. For these reflective films, a metal whose main component is aluminum is used. Board 1
While rotating at a low speed, the radiation curable resin 7 is applied in a donut shape (FIG. 2 (A)). The second substrate 4 is placed on top of this so that the reflection film on the information signal surface faces the radiation curable resin 7 (FIG. 2 (B)). The substrates 1 and 4 are integrally rotated at a high speed so that the radiation curable resin diffuses between the substrates 1 and 4 (FIG. 2C), and then the radiation (in FIG. 2) passes through the substrate 4 and the reflective film thereon. UV radiation is used) to cure the radiation-curable resin, and the two substrates are solidified and bonded together (FIG. 2D).

In this conventional example, an information signal is provided on each of the two superposed substrates, and a reflective film is formed on each of the information signals. It can be cured. For example,
When aluminum is used for the reflection film and ultraviolet rays are used as radiation, the transmittance of the aluminum film for ultraviolet rays is 1% or less, but the resin can be sufficiently cured.

Since the laminated disk of the thin substrate has a very large capacity, most of the soft contents are sufficient on one side, and one of the substrates to be superposed may be a mere dummy transparent plate. In this case, the radiation-curable resin can be quickly and easily cured with the radiation that passes through the transparent plate (Japanese Patent Application No. 5-58200).
-63668, Japanese Patent Application No. 5-195011).

It is also possible to form a semi-transparent film on one of the two substrates to reproduce both information surfaces from one side of the disc. In the production of this two-layer disc, one side is semi-transparent. Since it is a film, it is quick and easy to cure by ultraviolet rays.

[0010]

The radiation curable resin is applied in a donut shape while the substrate is rotated at a low speed, and the substrates to be laminated are stacked on top of each other, and the two substrates are integrally rotated at a high speed to apply the radiation curable resin to the substrate. If the substrate is rotated at a high speed before being spread to the inner peripheral side of the substrate when diffusing between the two, the inner periphery of the disc will not be sufficiently filled with the resin and a bonded disc with weak strength will be formed. Further, if the resin is sufficiently diffused between the two substrates, it is difficult to prevent the resin from sticking out of the center hole of the substrates, such as eccentricity when fixing the disc to the turntable of the player. Trouble occurs.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to prevent radiation-curable resin from squeezing out into a central hole of a substrate and to have high mechanical strength and excellent aesthetics. An object is to provide a thin optical information medium, an optical information medium manufacturing method, and an optical information medium manufacturing apparatus.

[0012]

The optical information medium of the present invention comprises:
A first substrate having a central hole, a second substrate having a central hole, and formed between the first substrate and the second substrate,
What is claimed is: 1. A disk-shaped optical information medium comprising a radiation curable resin for bonding the first substrate and the second substrate, further comprising a stopper for preventing the radiation curable resin from protruding from a hole of the substrate. In addition, at least half of the clamp area for clamping the optical information medium is filled with resin between the first substrate and the second substrate , and the stopper is Formed from sealant layer
The sealant layer is a printed radiation curable resin.
The above-mentioned object is achieved thereby. Another optical information medium of the present invention has a central hole
A first substrate, a second substrate having a central hole, and the first substrate
A first substrate and a substrate formed between the substrate and the second substrate;
A radiation-curable resin that is bonded to the second substrate
A disk-shaped optical information medium, wherein the radiation-curable resin is
Further stopper to prevent it from protruding from the hole in the board
Of the first substrate and the second substrate
Clamp for clamping the optical information medium between
At least half of the area is filled with resin.
The stopper is formed of a sealant layer,
The sealant layer is formed from a hot melt agent,
By doing so, the above object is achieved. Optical information medium of the present invention
The manufacturing method includes a first substrate having a central hole and a second substrate having a central hole.
A radiation curable resin is formed between the first and second substrates to form a single layer.
A method for manufacturing an optical information medium as a body, wherein
Radiation-cured resin formed on the outer periphery of the substrate
Use a radiation-curable resin that is higher than that of fat to form a sealant layer
A transparent substrate formed through the first substrate or the second substrate.
The radiation curable resin is cured by a ray of radiation to form the first group.
The plate and the second substrate are attached to each other, so that
Target is achieved. Another optical information medium manufacturing method of the present invention is
Radiation hardening between a first substrate and a second substrate having a central hole
Forming a resin and bonding the first substrate and the second substrate together
A method for manufacturing an optical information medium, comprising: an inner peripheral portion of the substrate
Applying a radiation-curable resin to the sealant layer
By forming and transmitting radiation through the first or second substrate
The radiation-curable resin is cured so that the first substrate and the second substrate are cured.
It is bonded to the substrate, which achieves the above objectives.
Be done. Another optical information medium manufacturing method of the present invention has a center hole.
Radiation curable resin is placed between the first and second substrates.
Form and bond the first substrate and the second substrate together
A method for producing an optical information medium, comprising using a hot melt agent
A sealant layer is formed on the inner periphery of the substrate, and the radiation-cured resin is
The first substrate and the second substrate sandwiching an oil and the sealing agent layer.
After pressing, pass through the first substrate or the second substrate
Curing the radiation curable resin by the radiation
Bonding the first substrate and the second substrate together
The above object is further achieved.

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BEST MODE FOR CARRYING OUT THE INVENTION The optical information medium (optical disk) of the present invention comprises a pair of substrates having a central hole bonded by a radiation curable resin, and prevents the radiation curable resin from protruding from the central hole of the substrate. It is further equipped with a stopper that Further, between the pair of substrates, at least half of the clamp area for fixing the optical disc to the turntable is filled with resin. As the stopper, a concave portion or a convex portion formed on the substrate is preferable.

When a groove substantially concentric with the center hole is formed on the substrate as a stopper, the bonding method when this groove is on the inner peripheral side of the clamp region is as follows.
That is, while rotating the substrate at a low speed, the radiation curable resin is applied in a donut shape on the outer side of the groove, and the substrate to be bonded is superposed thereon. Rotate two substrates together at high speed to
The radiation curable resin is diffused substantially uniformly between the substrates and outside the groove, and the radiation curable resin is cured by irradiating the radiation to solidify and bond the two substrates together.

When the groove is located on the outer peripheral side of the clamp area, the bonding method is as follows. While the substrate is rotated at a low speed, the radiation curable resin is applied in a donut shape on the outer side of the groove, and the radiation hardened resin is separately on the inner peripheral side of the groove. The resin layer is formed so as not to come into contact with the central hole, and the substrate to be laminated is stacked on it. The two substrates are rotated together at a high speed so that the radiation-curable resin is almost evenly diffused between the two substrates and outside the groove and on the inner circumference side of the groove in a range not in contact with the central hole, and the radiation is cured. Irradiation is performed to cure the radiation curable resin, and the two substrates are solidified and bonded together.

When the groove is located on the inner side of the clamp area, when the resin diffuses between the substrates after the two substrates are superposed, the groove serves as a reservoir for extra resin, and the inner side of the groove is located. The resin does not spread and prevents the resin from protruding from the center hole of the substrate. In addition, since the resin diffuses into the clamp area and is sufficiently filled, a disk having high strength can be formed.

When the groove is on the outer peripheral side of the clamp region, a thin radiation curable resin layer is previously provided on the inner peripheral side of the groove, separately from applying the radiation curable resin on the outer side of the groove in a donut shape. Since the two substrates are overlaid later, the resin can be sufficiently cured in the clamp area. Since the resin layer on the inner peripheral side is thin from the beginning and is applied so as not to come into contact with the central hole of the substrate, it does not protrude from the central hole.

Embodiments of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) A first embodiment of the optical information medium according to the present invention will be described.

FIG. 3 shows an optical disk of this embodiment. This optical disc is a disc-shaped substrate (thickness: 0.6 mm) 1
And the substrate (thickness: 0.6 mm) 4 is a radiation curable resin 7
It is integrally bonded via. An information signal surface 2 is provided on one surface of the first substrate 1. A reflection film 3 (thickness: 0.03 μm to 0.2 μm) 3 containing aluminum as a main component is formed on the information signal surface 2. An information signal surface 5 is provided on one surface of the second substrate 4, and a reflective film 6 is formed on the information signal surface 5. These information signal surfaces 2 are exposed through the radiation curable resin 7.
The two substrates 1 and 4 are bonded so that the substrates 5 and 5 face each other.

Grooves and pits are formed on the information signal surfaces 2 and 5 of the substrates 1 and 4, respectively. In the case of a rewritable optical disc, a recording film (not shown) or the like is deposited on the information signal surface 2 or 5 of at least one substrate 1 or 4.

Generally, the optical disc is provided with a clamp area (near the arrow in FIG. 3) for fixing the optical disc on the turntable of the recording / reproducing apparatus. The clamp area is an area having a donut shape, and in the case of a DVD, the area is 11 mm measured from the center of the disk.
To 16.5 mm. That is,
In the case of DVD, the clamping area is 22 mm inside diameter and 3 outside diameter.
It is a ring-shaped area of 3 mm.

In this embodiment, grooves 8 and 9 which are substantially concentric with the central circle are formed on the substrates 1 and 4, respectively. The function of the grooves 8 and 9 will be described in detail later. In the optical disc of this embodiment, the grooves 8 and 9 are
It has a depth of 0.3 mm or less and a width of 3 mm or less, and is formed on the inner side (side closer to the disc center) than the outer edge of the clamp region. In order to maintain the strength of the substrate at a sufficient level, it is preferable that the depth of the groove is less than half the thickness of the substrate.

If the grooves 8 and 9 are formed outside the outer edge of the clamp region (outer peripheral side of the substrate), the clamp region is not sufficiently filled with resin. In the case of the present embodiment, since the radiation curable resin is used for bonding the substrates, the substrate interval (about 50 μm) is expanded about 5 times as compared with the substrate interval (about 10 μm) when the hot melt adhesive is used. ing. From the experiments conducted by the inventors of the present application, it was revealed that if the clamp region is not sufficiently filled with the radiation curable resin, the space between the substrates is widened and the optical disc cannot be stably fixed to the turntable.

It has been found that to achieve a stable clamp, at least half of the clamp area must be filled with radiation curable resin. That is, in the case of a DVD, in the grooves 8 and 9, the distance between the center (groove center) and the disk center is 13.75 (= 11/2 + 16.5 / 2) m.
It must be arranged so that it is less than or equal to m. When the grooves 8 and 9 having a width of 3 mm are formed such that the groove centers are located within a region of 12.5 mm or less from the center of the disc, the radiation curable resin can substantially fill the entire clamp region. Therefore, it is preferable that the grooves 8 and 9 are provided so that the center thereof is within a range of about 12.5 mm or less from the center of the disk.

Since the radiation curable resin layer 7 does not always completely fill the insides of the grooves 8 and 9, the radiation curable resin layer 7 is outside the outer edges of the grooves 8 and 9 or the inner edge of the groove including the grooves. It will be located outside. FIG. 3 shows, as an example, a case where resin is filled outside the inner edge of the groove.

When the substrates 1 and 4 are formed by injection molding using a stamper provided with an information signal, the grooves 8 and 9 can be formed by a jig for attaching the stamper. By adjusting the shape and size of the mounting jig,
The shape and size of the grooves 8 and 9 can be controlled. The groove 8
The shapes of 9 and 9 are not limited to those shown.
Also, only one groove, not both grooves 8 and 9, may be formed in one of the substrate 1 or the substrate 4. Also,
A plurality of grooves may be formed close to each other on one substrate.

FIG. 4 shows a state of injection molding of the substrate. A doughnut-shaped stamper 12 having a hole in the center is fixed to one surface of a cylindrical movable mold 11 by a mounting jig 13. At the end of the mounting jig 13, a ring-shaped convex portion 13
a is provided, and the convex portion 13 a presses the stamper 12 against the movable-side metal fitting 11. The substrate 1 or the substrate 4 is manufactured by injecting resin from the right side in the drawing into the cavity 15 formed between the movable side mold 11 and the fixed side mold 14 and cooling. At this time, the protrusion 1a of the mounting jig 13 of the stamper 12 causes the substrate 1
Alternatively, the groove 8 or 9 is formed in the substrate 4. Therefore, the shapes and sizes of the grooves 8 and 9 are the same as those of the convex portion 1 of the mounting jig 13.
3a.

Next, an example of the optical disk manufacturing method according to the present invention will be described with reference to FIGS.

First, a substrate 1 having a first information signal surface 2 provided on one surface thereof is manufactured by injection molding using a transparent resin such as polycarbonate. A reflective film is formed on the information signal surface by a sputtering method or a vacuum evaporation method. Also,
The substrate 4 having the second information signal surface provided on one surface is formed by the injection molding method or the like, and the reflection film is formed thereon by the sputtering method or the vacuum evaporation method. For these reflective films, a metal whose main component is aluminum is used.

While rotating the substrate 1 at a low speed (20 to 120 rpm), the radiation curable resin 7 is applied in a donut shape to the region outside the groove 8 of the substrate 1 (FIG. 5A). The second substrate 4 is laid on top of it so that the reflection film on the information signal surface faces the radiation curable resin 7 (FIG. 5 (B)). The radiation-curable resin diffuses between the substrate 1 and the substrate 4, but the grooves 8 and 9 serve as reservoirs for the extra resin, and the resin does not spread to the inner circumference of the groove. It prevents it from protruding. Instead of providing a continuous ring-shaped groove, a plurality of recesses may be arranged so as to be close to each other at positions equidistant from the center of the disc.

The substrates 1 and 4 are integrally and at high speed (300 to 50).
(00 rpm), whereby the radiation curable resin is diffused substantially uniformly between the two substrates and on the outer peripheral side of the groove (FIG. 5 (C)). In this embodiment, this step is performed using the manufacturing apparatus shown in FIG. The device of FIG.
A table 111 for rotating the optical disk, a boss 112 having a suction port 113, and a suction pump 114 connected to the suction port 13 are provided. Since the ultraviolet curable resin has fluidity before being cured, the suction pump 11 is passed through the suction port 113 provided in the boss 112 on the table 111.
If the radiation curable resin is sucked in step 4, the radiation curable resin can be spread evenly between the substrates. Suction port 1 of this embodiment
The size of 13 has an inner diameter of 1 mm or more, and the number thereof is 2 or more. The suction force is experimentally optimized according to the viscosity of the radiation curable resin, the rotation speed and rotation time of the table 111, and the like.

It is preferable that the table 111 has a slightly smaller outer diameter than the first substrate 1 and the second substrate 4.
This is to prevent a part of the radiation curable resin protruding from the outer peripheral ends of the two rotating substrates from spreading to the table 11. In this embodiment, the radius Rt of the turntable 14 is set to 59 mm or less, which is 1 mm or more shorter than the radius Rs (= 60 mm) of the substrate. If the radius Rt of the turntable 114 is too small, the optical disc cannot be stably supported. Therefore, the radius Rt of the table 111 is about 7 times the radius Rs of the optical disc.
It preferably has a size of 0% or more.

As described above, in this embodiment, the centripetal force is applied by sucking the radiation curable resin when the substrate is rotated.
As a result, a large amount of resin is prevented from moving to the outer edge of the optical disc. Further, regarding the resin protruding to the outer edge portion of the optical disc, the size of the table is made smaller than that of the optical disc to prevent the resin from adhering to the table and soiling the disc.

Further, by sucking the resin from the center hole of the optical disk, the resin can be surely retained in the clamp area even at the time of high speed rotation, and the resin can be uniformly diffused. Further, since the excess resin protruding from the end face of the center hole of the optical disc is sucked out from the suction port 113 and is removed cleanly, an optical disc having an excellent appearance is provided.

In place of the suction port 113, the boss 11
Even if a sponge for absorbing the radiation curable resin 5 is attached to the position of the second suction port 113, the extra resin protruding from the end face of the center hole of the optical disc can be removed cleanly.

Next, radiation is applied through the substrate 4 and the reflection film on the substrate 4 to cure the radiation curable resin, and the two substrates are integrally fixed and bonded (FIG. 5D).

Ultraviolet rays (UV) may be used as the radiation, and an ultraviolet curable resin may be used as the resin. If the thickness of the metal reflective film containing aluminum as the main component is 0.1 μm or less, it transmits a small amount of ultraviolet rays (transmittance is 1% or less) to cure the ultraviolet curable resin between the two reflective films. You can

A protective film made of a radiation curable resin may be previously formed on the reflective film of the first or second substrate, and then a radiation curable resin for bonding may be applied, superposed, and irradiated with radiation.

When the radiation curable resin is cured by irradiation with radiation, heat is generally generated, and the heat may cause the substrate to warp slightly. Therefore, while irradiating with radiation, the transparent plate is pressed from above the second substrate by the transparent plate, the second substrate,
When the resin is cured by the radiation that passes through the second reflective film,
It is possible to fabricate a bonded disc in which the tilt of the disc can be almost ignored without warping the substrate. FIG. 7 shows this embodiment, in which the transparent plate 10 holds the integrated first and second substrates. The transparent plate may be a glass plate.

Here, an example in which two substrates on which information signals are recorded is bonded to each other has been described. However, even if one substrate is a dummy substrate on which no information signal is recorded, bonding can be performed in the same manner. it can.

Further, even in the case of a two-layer disc in which a semitransparent film is formed on the information signal surface of the substrate 4, the radiation curable resin can be irradiated with the radiation through the substrate 4 having the semitransparent film, so that it is easy. Can be stuck to.

Although the grooves 8 and 9 of the substrate prevent the excess resin from diffusing toward the inner peripheral side of the groove, there is no guarantee that the resin is uniformly accumulated in the grooves 8 and 9. If the resin in the grooves 8 and 9 becomes non-uniform and the air portion and the resin portion are mixed, the appearance is spoiled. Therefore, the reflective films 3, 6 are also formed on the grooves 8 and 9.
By forming the above, the inside of the grooves 8 and 9 cannot be seen from the outside and the appearance can be maintained. FIG. 3 shows a disk cross section of this structure.

(Embodiment 2) Next, with reference to FIG. 8 and FIG. 9, an optical disk in which the groove on the substrate is formed outside the outer edge of the clamp area will be described.

In order to prevent the resin from protruding from the central hole of the substrate, the resin must be applied to the outside of the outer edge of the groove. However, in this case, there is no resin in the clamp area, and the disc cannot be sufficiently fixed on the turntable. Therefore, before applying the radiation curable resin in a donut shape on the outside of the groove 8, a means for separately forming the radiation curable resin layer 16 on the inner peripheral side of the groove is used. For this purpose, as shown in FIG. 8, the roller 1 having a width of about 5 to 10 mm is used.
7, there is a method of forming a resin layer. Also at this time, it is desirable to form the resin layer 16 at a position not in contact with the center hole so that the resin does not overflow into the center hole of the substrate.

FIG. 9 shows the laminated disk of this embodiment. The names of the respective parts are the same as in the embodiment of FIG. The groove of the optical disk of the present embodiment is formed outside the outer edge of the clamp area (near the arrow in FIG. 9) and is made of the radiation curable resin 7
Is separately applied on the outer peripheral side and the inner peripheral side of the groove. As a result, the resin may be slightly unevenly filled, but the clamp region can be sufficiently filled with the resin and cured.

The above-mentioned first and second embodiments are both double-sided reproduction type optical disks. In the case of a single-sided reproduction type, the substrate 4 may be a transparent plate (dummy plate) having no reflective film or information signal surface. If the substrate 4 is a dummy plate, the radiation curable resin can be irradiated with radiation through the transparent substrate 4,
The radiation-curable resin can be cured in a shorter time than in the case of double-sided reproduction described above, and the production tact can be shortened.

Further, even in the case of a two-layer disc in which a semitransparent film is formed on the information signal surface of the substrate 4, the radiation effect resin can be irradiated with the radiation through the substrate 4 having the semitransparent film, which is easy. Can be stuck to.

(Embodiment 3) A third embodiment of the optical information medium according to the present invention will be described with reference to FIGS. 10, 11, 12 and 13A to 13D.

In the optical disc of the present embodiment, FIG.
As shown in FIG. 1, the information signal surface 2 is provided on one surface of the first substrate 1.
Is provided. On the information signal surface 2, a reflective film 3 such as a metal containing aluminum as a main component is formed. Further, the information signal surface 5 is provided on one surface of the second substrate 4, and the reflective film 6 is formed on the information signal surface 5. Protrusions (height: 0.01 to 0.
2 mm, width: 0.1 to 2 mm) 40 and grooves (depth: 0.
05-0.3 mm, width: 0.3-3 mm) 50. The radiation curable resin layer 7 is provided between the substrate 1 and the substrate 4 and outside the outer edges of the protrusions 40 and the grooves 50, or outside the inner edges of the protrusions and the grooves including the protrusions 40 and the grooves 50. . FIG. 10 shows an example in which resin is filled outside the inner edges of the protrusions and the grooves.

The area indicated by the arrow in FIG. 10 is a clamp area for fixing the optical disk to the turntable of the reproducing apparatus, and it is necessary that the radiation curable resin is sufficiently hardened there. For that purpose, the protrusion 40 and the groove 50 need to be formed closer to the central hole than the center of the clamp region. Further, the two substrates need to be positioned at the center of the center hole and sufficiently cured so that eccentricity does not occur.

The protrusion 40 and the groove 50 of this embodiment function as stoppers for preventing the radiation curable resin from protruding from the central hole, like the grooves 8 and 9 of the optical disk of FIG. The protrusions 40 may be provided on the substrate 1 without providing the grooves 50 on the substrate 4. In that case, only the protrusion 40 functions as a stopper for the radiation curable resin. A protrusion may be provided on the substrate 4 instead of the groove 50. In that case, the protrusion of the substrate 4 needs to be provided at a position where it does not collide with the protrusion 40 of the substrate 1. The protrusion 40 and the groove 50 of this embodiment are in the shape of a continuous ring surrounding the central hole of the substrate. However, the protrusion 40
The groove 50 does not necessarily have to be continuous. For example, the plurality of protrusions may be arranged close to positions equidistant from the center of the disc. Alternatively, two substrates may be attached so that the plurality of protrusions arranged on one substrate and the plurality of protrusions arranged on the other substrate are engaged with each other.

A method of manufacturing the optical disk shown in FIG. 10 will be described below with reference to FIGS. 11, 12 and 13A to 13D.

Using a transparent resin such as polycarbonate,
The substrate 1 having the first information signal surface on one side is manufactured by injection molding or the like. A reflective film is formed on the signal surface by sputtering or vacuum evaporation. Further, the substrate 4 having the second information signal surface provided on one surface is formed by injection molding or the like, and the reflection film is formed thereon by the sputtering method or the vacuum evaporation method.
For these reflective films, a metal whose main component is aluminum is used.

The substrate 1 is provided with a concentric protrusion 40 which is substantially equivalent to the central circle, and the substrate 4 is provided with a groove 50 so as to face the protrusion 40 of the substrate 1. When the injection molding is performed using the stamper provided with the information signal, the projection 40 and the groove 50 can be formed by the jig for mounting the stamper. 11 and 12 show the state of the injection molding. The stamper 12 is fixed to the movable mold 11, the resin is injected into the cavity 15 between the fixed mold 14 and the mold, and the substrate is manufactured by cooling. At this time, the groove 50 of the substrate can be produced by providing the jig 13 shown in FIG.
Further, by providing the recess 13b in the jig 13, the protrusion 40 of the substrate can be manufactured.

While rotating the substrate 1 shown in FIG. 13A at a low speed, the radiation curing resin 7 is applied to the outside of the protrusion 40 in a donut shape or a spiral shape. Then, Figure 1
The second substrate 4 is placed on the upper surface of the substrate 1 shown in FIG. 3B so that the reflection film on the information signal surface faces the radiation curable resin 7.
Then, as shown in FIG. 13C, the radiation curable resin 7
Will diffuse between the substrate 1 and the substrate 4, but the radiation curable resin will stop at the protrusions 40 and will prevent the radiation curable resin from squeezing out from the protrusions to the inner circumference.

The substrate 1 and the substrate 4 are integrally rotated at a high speed for 2
The radiation curable resin 7 is diffused substantially uniformly between the substrates and on the outer peripheral side of the protrusion 40. After that, FIG.
Radiation is irradiated through the substrate 4 shown in (D) and the reflection film on the substrate 4 to cure the radiation curable resin, and the substrate 1 and the substrate 4 are integrally fixed and bonded together.

Ultraviolet rays (UV) may be used as the radiation, and an ultraviolet curable resin may be used as the resin. If the thickness of the metal reflective film containing aluminum as the main component is 0.1 μm or less, it transmits a small amount of ultraviolet rays (transmittance is 1% or less) to cure the ultraviolet curable resin between the two reflective films. You can

After forming a protective film of a radiation curing resin on the reflective film of the first substrate or the second substrate in advance, as shown in FIG.
As shown in 3 (A) to 3 (D), a radiation curable resin for laminating may be applied, superposed, and irradiated with radiation.

Example 4 Next, with reference to FIG. 14, a method of shaping the radiation curable resin on the outer peripheral edge of the substrate will be described.

An optical disc bonded with two substrates must sufficiently withstand mechanical strength such as dropping and impact.
However, the radiation curable resin for bonding two substrates is diffused only to the signal recording portion and the resin does not reach the substrate end face sufficiently, or even if a part of the resin reaches the substrate end face, the resin Uniform diffusion is very difficult. When the resin is cured by irradiation with radiation while the resin is unevenly diffused, both substrates are likely to be peeled off from the end face of the substrate due to dropping or impact, and the mechanical strength of the optical disk is lowered. Therefore, as shown in FIG. 14, the outer diameter φa of the outer peripheral edge on the bonding surface side of both the first substrate 1 and the second substrate 4 is the outer diameter of the outer peripheral edge on the opposite surface side of the bonding surface. The diameter is set to be slightly smaller than φb, and the outer peripheral end surface of each substrate is tapered to form inclined surfaces 18 and 19 diagonally facing each other. As a result, a recess is formed along the outer circumference of the optical disc, and the radiation curable resin is provided so as to fill the recess. At this time, the tapered surface (inclined surface) of the substrate end may be formed on either one of the first substrate and the second substrate.
Further, the shape of the tapered surface (inclined surface) is such that outer diameter φa ≦ outer diameter φb
Any shape may be used as long as it satisfies the relationship.

The radiation curable resin formed on the inclined surfaces 18 and 19 of the substrate ends is not shown, but the radiation curable resin is shaken off by rotating a rotary table provided at the lower part of the substrate at a high speed. Only the edge surface of the substrate is formed, and it is not formed in a uniform state. Therefore, the rotary transfer roller 20 capable of transferring is formed in a relative shape with a recess formed by bonding the first substrate 1 and the second substrate 4, or with a relative shape slightly smaller than the recess.
Is provided and driven in the direction of the arrow shown in FIG. 5 so as to come into contact with the substrate. At this time, it is preferable that the rotary table is switched to low speed rotation, the rotary transfer roller 20 is brought into contact with the rotary table, and the rotary table is rotated in a direction opposite to the rotation direction of the rotary table, but the rotary transfer roller 20 is fixed. good. Further, in order to constantly supplement the radiation-curable resin, the rotary table extracts the radiation-curable resin from the extraction nozzle 21 in a timely manner and keeps the rotation transfer roller 20 always transferable, thereby shaping the substrate end surface. Can be maintained, and by curing by irradiation in that state,
An optical disk with high mechanical strength can be manufactured.

(Embodiment 5) Next, a method of hardening the outer peripheral end portions of two superposed substrates will be described with reference to FIG.

Radiation has a strong linearity, and, for example, the end face portion of the substrate is not sufficiently irradiated and is not cured within a predetermined irradiation time. Therefore, while the rotary table 22 is rotated at a low speed, the reflection plate 2 that can irradiate the end face of the substrate
4 is provided between the two substrates, and
The radiation curable resin 7 on the end surface of the substrate can be uniformly and stably cured.

Apart from the structure shown in FIG. 15, a truncated cone-shaped mirror may be provided around the substrate. In this case, the table need not be rotated.

(Embodiment 6) FIG. 16 shows another embodiment of the optical information medium of the present invention. 1 and 4 are substrates, 2 and 5 are first
And a second information signal, 3 and 6 are reflective films, 90 is a sealant layer, and 70 is a radiation curable resin layer. Due to the effect of the sealing agent layer 90, an information recording medium can be obtained in which the resin does not protrude into the central hole.

The manufacturing method of the present invention in the case of a double-sided reproduction bonded disk will be described with reference to FIGS. 17 (A) to 17 (D). The substrate 1 provided with the first information signal surface 2 on one surface and the substrate 4 provided with the second information signal surface 5 on one surface are manufactured by injection molding using a transparent resin such as polycarbonate. The reflection films 3 and 6 are formed on the information signal surface 2 and the information signal surface 5 by a sputtering method or a vacuum evaporation method. For these reflective films, for example, a metal whose main component is aluminum is used.

While rotating the substrate 1 at a low speed, the radiation curable resin 70, which is the main adhesive agent, is applied to the outer peripheral portion of the disc, and the radiation curable resin 90 having a higher viscosity than the radiation curable resin 70 is applied to the inner peripheral portion of the disc in a donut shape ( FIG. 17A). On top of that, the second substrate 4 is provided with the information signal surface 5 and the radiation curing resin 7 is provided.
They are piled up toward 0 and 90 (FIG. 17 (B)).

If there is no radiation curable resin 90, the substrate 4
When the above is stacked on the substrate 1, the radiation curable resin 70 diffuses between the substrates 1 and 4 and protrudes from the center hole of the substrates 1 and 4. If the resin is hardened before spreading to the inner circumference, the inner circumference of the disk will not be sufficiently filled with resin and a bonded disk with weak strength will be formed.

On the other hand, when the radiation-curable resin 90 is present, the radiation-curable resin 90 has a high viscosity, so that the radiation-curable resin 90 diffuses little and the substrate 1
And do not protrude from the center holes of 4. Radiation curable resin 70
Is diffused, but since the radiation curable resin 90 is present on the inner circumference, it is not blocked by the radiation curable resin 90 and does not protrude into the central holes of the substrates 1 and 4.

The substrates 1 and 4 are integrally rotated at a high speed so that the radiation curable resin is substantially uniformly diffused between the two substrates (FIG. 17C). Radiation is radiated through the substrate 4 and the reflection film on the substrate 4 to cure the radiation curable resin, and the two substrates are integrally fixed and bonded (FIG. 17D).

Generally, ultraviolet rays are used as the radiation and an ultraviolet curable resin is used as the resin. If the thickness of the metal reflection film containing aluminum as a main component is 0.1 μm or less, it allows a small amount of ultraviolet rays to pass therethrough, so that the ultraviolet curable resin between the two reflection films can be cured.

After forming a protective film of a radiation-curable resin on the reflective film of the first or second substrate in advance, as shown in FIGS. 17A to 17D, a radiation-curable resin for bonding is formed. You may apply | coat, superimpose, and irradiate with radiation. Although there is a drawback that the number of steps for forming the protective film increases, the protective film protects the reflective film, so that the degree of freedom in selection of the radiation curable resin for bonding is increased and the weather resistance of the reflective film can be enhanced.

Although the method of forming the sealing agent layer 90 by the spin coating method using the radiation curable resin has been described, the sealing agent layer 9 may be formed by printing. A radiation-curable resin having a viscosity higher than a certain level is easier to apply by printing than by spin coating.

As the sealant layer 90, a hot melt agent having a viscosity higher than that of the radiation curable resin 70 can be used. The hot melt agent can be applied by, for example, a roll coater.

Here, an example of bonding two substrates on which information signals are recorded has been described. However, even if one of the substrates is a dummy substrate on which no information signal is recorded, the same bonding is possible. it can.

Further, even in the case of a two-layer disc in which a semitransparent film is formed on the information signal surface of the substrate 4, the radiation effect resin can be easily irradiated with the radiation through the substrate 4 having the semitransparent film. Can be stuck to.

Since the optical disk of the present invention has the sealant layer formed on the inner peripheral portion of the substrate, the radiation curable resin coated on the surface of the substrate does not protrude into the center hole even when diffused to the inner periphery. There is no problem such as eccentricity when fixing the disc to the turntable of the player. Also,
Since the resin is sufficiently filled up to the inner circumference of the disc, the bonding strength can be increased.

(Embodiment 7) Next, still another embodiment of the optical information medium according to the present invention will be described.

In the optical disc of this example, a weather-resistant dye is mixed in the radiation curable resin layer formed between the substrates. Here, an example in which ultraviolet rays are used as an example of radiation and an ultraviolet curable resin is used as an example of a radiation curable resin will be described.

In the conventional optical disc, the ultraviolet curable resin is decolorized with the passage of time, and the aesthetic appearance of the bonded substrates is deteriorated with the passage of time.

Since the optical disc of this embodiment contains a UV-curable resin mixed with a weather-resistant dye, the radiation-curable resin is prevented from being decolorized, and the aesthetic appearance of the bonded substrates is impaired by aging. Can be prevented.

An optical disc manufacturing method according to the embodiment of the present invention will be described.

As the UV curable resin, a UV curable resin in which a pigment having weather resistance is uniformly mixed in advance is used. Using this UV curable resin 7
By the same steps as the conventional steps shown in (A) to (D), it is possible to manufacture an optical disc in which a radiation-curable resin layer formed between substrates is mixed with a dye having weather resistance.

Here, an example is described in which two substrates on which information signals are recorded are bonded to each other. However, even if one of the substrates is a dummy substrate on which no information signal is recorded, the same bonding is possible. it can.

The manufacturing method of this embodiment can also be applied to the manufacture of optical disks of other embodiments.

(Embodiment 8) Next, still another embodiment of the optical information medium according to the present invention will be described.

In the optical disk of this embodiment, the radiation curable resin layer formed between the substrates has a radiation curable resin layer whose color density varies depending on the degree of curing. Here, an example in which ultraviolet rays are used as an example of radiation and an ultraviolet curable resin is used as an example of a radiation curable resin will be described.

Conventionally, in order to confirm the degree of curing of the ultraviolet curable resin, the only method is to break the bonded substrates and directly perform the destructive inspection to measure the hardness of the ultraviolet curable resin. It was difficult to obtain a uniform degree of cure with the disc.

The optical disc of this embodiment uses a radiation-curable resin layer whose color density varies depending on the degree of curing, so that the degree of cure of the radiation-curable resin layer can be inspected nondestructively based on the color density. The curing degree of each disk can be made uniform by completing the curing of the radiation curable resin at a constant concentration.

As the ultraviolet curable resin whose color density changes depending on the degree of curing, for example, ultraviolet curable resin SD-1700 manufactured by Dainippon Ink and Chemicals can be used.

The optical disc manufacturing method of this embodiment will be described.

As the ultraviolet curable resin, a resin whose color density changes depending on the degree of curing is used. Using this ultraviolet ray emitting resin, the ultraviolet curing resin is applied to the substrate 1 by the same process as the conventional process shown in FIGS. 2 (A) to 2 (D), and the second substrate 4 is provided thereon with the information signal surface. The upper reflection film is laminated toward the radiation curable resin, and the substrate 1 and the substrate 4 are integrally rotated at high speed so that the radiation curable resin diffuses between the substrate 1 and the substrate 4.

Unlike the conventional process shown in FIG. 2D, when curing the ultraviolet curable resin, an ultraviolet irradiator 35 and a sensor 36 for measuring the color density of the ultraviolet curable resin as shown in FIG. 18 are used. Use the device you have.

When the ultraviolet curing resin is irradiated with ultraviolet rays from the ultraviolet irradiation device 35 through the substrate 4, the color density of the ultraviolet curing resin is measured using the sensor 36. When the color density of the UV curable resin reaches the color density of the UV curable resin at the time of complete curing, which has been measured in advance, the irradiation of UV rays is stopped. At this point, the UV curable resin is completely cured. A color difference meter, for example, can be used as the sensor 36.

As a result, the complete curing of the UV curable resin can be confirmed without performing a destructive inspection, the 100% inspection of manufactured products can be performed, and the curing degree of each disk can be made uniform.

Here, an example is described in which two substrates on which information signals are recorded are bonded to each other. However, even if one substrate is a dummy substrate on which no information signal is recorded, the same bonding is possible. it can.

(Embodiment 9) Next, still another embodiment of the method for manufacturing an optical information medium according to the present invention will be described. here,
An example in which ultraviolet rays are used as an example of radiation and an ultraviolet ray curable resin is used as an example of a radiation curable resin will be described.

When the ultraviolet curable resin is cured, the ultraviolet curable resin layer is cured from the side closer to the light source, so that there is a problem in that the outer peripheral portion of the substrate after bonding is largely warped to the irradiation light source side.

Substrate 1 is manufactured by the same process as the conventional process shown in FIGS.
UV-curable resin is applied to the second substrate 4, and the second substrate 4 is superposed thereon so that the reflection film on the information signal surface faces the radiation-curable resin, and the substrates 1 and 4 are integrally rotated at a high speed to produce the radiation-curable resin 7 Diffuse between the substrate 1 and the substrate 4.

Unlike the conventional process shown in FIG. 2D, when the ultraviolet curable resin 7 is cured, as shown in FIG.
This is performed by using an apparatus having a structure including ultraviolet irradiators 35 and 37. The ultraviolet ray irradiator 35 irradiates the ultraviolet ray curable resin 7 through the substrate 4, and the ultraviolet ray irradiator 37 on the opposite side cures the ultraviolet ray curable resin 7 from the substrate 4 side and from the substrate 1 side of the ultraviolet ray curable resin 7.

When the ultraviolet curable resin 7 is cured, the ultraviolet irradiators 35 and 37 are alternately or simultaneously irradiated for a fixed period of time. As a result, the ultraviolet curable resin 7 cures and contracts substantially evenly from both sides of the substrates 1 and 4, and the warpage of the substrates 1 and 4 due to the uneven curing contraction of the ultraviolet curable resin 7 is eliminated.

By the above method, an optical disk can be obtained in which the first substrate 1 and the second substrate 4 are integrated by the ultraviolet curable resin 7 and the warp amount is small.

When the ultraviolet transmittances of the substrates 1 and 4 are different, the intensity or irradiation time of the ultraviolet irradiators 35 and 37 is adjusted so that the irradiation light amount is adjusted between the substrate 1 side and the substrate 4 side of the ultraviolet curing resin 7. The same effect can be obtained by changing it.

Even when only the ultraviolet irradiator 35 is used, the substrates 1 and 4 may be inverted with the ultraviolet curable resin 7 sandwiched therebetween, or the ultraviolet irradiator 35 may be moved to the ultraviolet irradiator 37 side. The same effect can be obtained with.

The same effect can be obtained by using, as the substrate 1 or the substrate 4, a dummy substrate having no information signal surface or a reflective film.

[0150]

According to the present invention, it is possible to provide a laminating disk for a thin substrate and a manufacturing method and a manufacturing apparatus therefor, in which the resin does not squeeze out into the center hole of the substrate and the appearance is maintained.

According to the optical disc of the present invention, since the radiation curable resin is provided with the stopper for preventing the resin from protruding from the central hole of the substrate and at least half of the clamp region of the optical disc is filled with the resin, the center of the substrate is The resin does not squeeze out into the holes, and the strength of the clamp area is maintained high, so that stable clamping is achieved.

The optical disc of the present invention serves as a stopper.
When the sealant layer is formed on the inner circumference of the substrate, the radiation-curable resin applied to the substrate does not protrude into the center hole even if it is diffused in the direction of the center hole. There will be no trouble.

By sucking the radiation-cured resin before curing from the center hole of the substrate, it is possible to suppress the movement of the resin to the outer peripheral portion of the substrate, and it is possible to remove the resin protruding from the center hole of the substrate. By making the outer diameter of the table for rotating the substrate smaller than the outer diameter of the substrate, it is possible to prevent the resin protruding from the outer peripheral edge of the substrate from adhering to the table.
If the protruding radiation curable resin is removed with a jig or the like before curing, an optical disc with less eccentricity can be obtained.

If a weather-resistant dye is mixed in the radiation-curable resin, decolorization of the radiation-curable resin can be prevented, and the aesthetic appearance of the bonded substrates can be prevented from being impaired due to aging.

If a radiation-curable resin whose color density changes depending on the degree of cure of the radiation-curable resin is used, the color density is measured and the degree of cure of the radiation-cured resin between the bonded substrates is measured nondestructively. Therefore, the curing degree of each optical disk can be made uniform by completing the curing at a certain concentration.

When curing the radiation-curable resin, the radiation-curable resin layer is irradiated with the radiation by transmitting the radiation through both the first and second substrates at least once at the same time or one at a time. It is possible to prevent the warp of the bonded substrates, which is caused by the shrinkage of the radiation curable resin, by curing from both the first substrate side and the second substrate side.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional optical disc.

2A to 2D are perspective views showing a manufacturing process of a conventional optical disc.

FIG. 3 is a sectional perspective view of an embodiment of an optical disc according to the present invention.

FIG. 4 is a partial cross-sectional view of an injection molding apparatus used for manufacturing the substrate of the optical disc of the present invention.

5A to 5D are perspective views showing a manufacturing process of an optical disc according to the present invention.

FIG. 6 is a partial cross-sectional view of an apparatus used to manufacture the optical disc of the present invention.

FIG. 7 is a cross-sectional view showing a manufacturing process of an optical disc according to the present invention.

FIG. 8 is a perspective view showing a manufacturing process of an optical disc according to the present invention.

FIG. 9 is a sectional perspective view of another embodiment of the optical disc according to the present invention.

FIG. 10 is a sectional perspective view of still another embodiment of the optical disc according to the present invention.

FIG. 11 is a partial cross-sectional view of another injection molding apparatus used for manufacturing the substrate of the optical disc of the present invention.

FIG. 12 is a partial cross-sectional view of still another injection molding apparatus used for manufacturing the substrate of the optical disc of the present invention.

13A to 13D are perspective views showing a manufacturing process of another optical disc according to the present invention.

FIG. 14 is a sectional perspective view showing a manufacturing process of the optical disc according to the present invention.

FIG. 15 is a cross-sectional view showing the manufacturing process of the optical disc according to the present invention.

FIG. 16 is a sectional perspective view of still another embodiment of the optical disc according to the present invention.

17A to 17D are perspective views showing a manufacturing process of still another optical disc according to the present invention.

FIG. 18 is a perspective view showing a manufacturing process of the optical disc according to the present invention.

FIG. 19 is a perspective view showing a manufacturing process of an optical disc according to the present invention.

[Explanation of symbols]

1 Substrate on which the first information signal surface is formed 2, 5 Information signal surface 3, 6 reflective film 4 Substrate on which the second information signal surface is formed 7 Radiation curable resin 8 and 9 grooves 10 transparent plate 11 Movable mold 12 stampers 13 Stamper mounting jig 14 Fixed mold 15 cavities 16 Radiation curable resin layer 17 Laura

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sakae Noda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 4-10242 (JP, A) JP 5- 20714 (JP, A) JP-A-2-21438 (JP, A) JP-A-2-94040 (JP, A) JP-A-62-231436 (JP, A) JP-A-63-63146 (JP, A) JP-A-62-195738 (JP, A) JP-A-63-50929 (JP, A) JP-A-63-239628 (JP, A) JP-A-63-9046 (JP, A) JP-A-63-275052 (JP, A) Actual Kaihei 1-133227 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B 7/24 G11B 7/26

Claims (5)

(57) [Claims] 1. A first substrate having a central hole, a second substrate having a central hole, and a first substrate formed between the first substrate and the second substrate.
A disk-shaped optical information medium, comprising: a radiation-curable resin for bonding the substrate to the second substrate, and a stopper for preventing the radiation-curable resin from protruding from the hole of the substrate. Moreover, between the first substrate and the second substrate, at least half of the clamp region for clamping the optical information medium is filled with resin , and the stopper is a sealant. Formed of a layer, the sealant layer being formed by a printed radiation curable resin
Optical information media that are being used . 2. A first substrate having a central hole, a second substrate having a central hole, and a first substrate formed between the first substrate and the second substrate.
A disk-shaped optical information medium, comprising: a radiation-curable resin for bonding the substrate to the second substrate, and a stopper for preventing the radiation-curable resin from protruding from the hole of the substrate. Moreover, between the first substrate and the second substrate, at least half of the clamp region for clamping the optical information medium is filled with resin , and the stopper is a sealant. An optical information medium , which is formed of a layer , and the sealant layer is formed of a hot melt agent . 3. A method for manufacturing an optical information medium in which a radiation curable resin is formed between a first substrate and a second substrate having a central hole to integrate the first and second substrates, the substrate comprising: A sealant layer is formed on the inner peripheral portion of the substrate by using a radiation curable resin having a viscosity when uncured is higher than that of the radiation curable resin formed on the outer peripheral portion of the substrate, and the first substrate or the second substrate is formed. curing the radiation curable resin by radiation transmitted, an optical information medium manufacturing method to align Ri bonded to said first substrate and the second substrate. 4. A radiation curable resin is formed between a first substrate having a center hole and a second substrate to form the first substrate and the second substrate.
A substrate and bonded Ri matching the optical information medium manufacturing method, to form a sealant layer by printing a radiation curable resin to the inner peripheral portion of the substrate, the radiation transmitted through the first or second substrate the radiation curable resin is cured, the optical information medium manufacturing method combining Ri stuck to the substrate of the substrate and the second first. Between the first substrate and a second substrate having a 5. A center hole, an optical information medium manufacturing method combining Ri stuck to the substrate of the substrate and the second first forming a radiation-curable resin A sealant layer is formed on the inner peripheral portion of the substrate using a hot melt agent, and the radiation curable resin and the sealant layer are sandwiched between the first substrate and the second substrate. Then, the radiation-curable resin is cured by the radiation that passes through the first substrate or the second substrate to separate the first substrate and the second substrate.
The optical information medium manufacturing method is laminated Ri.