JPH10199050A - Manufacture of information storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an information storage medium at a low manufacturing cost without warping disk, by forming a label simultaneously with the resin molding of disk. SOLUTION: A resin molding die is constituted of an openable/closable fixed die 1 and a movable die 2, and a cavity 4 is formed on its central void part. A feeding roller 12 and a take-up roller 13 for loading a stamping sheet 11 are installed on the upper part and the lower part of the fixed die 1, and label material is held in the state being laminated on the surface of the stamping sheet 11 opposite to a stamper 3, and is transferred to the disk simultaneously with the molding of an optical disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an information storage medium, and more particularly, to a molding die composed of a separable first die and a second die, and holding a label material. The present invention relates to a method for manufacturing an information storage medium capable of forming a label simultaneously with molding using a stamping sheet.

[0002]

2. Description of the Related Art Generally, an optical disk, which is a large-capacity information storage medium, is manufactured by preparing a metal master, a mother, and a stamper from a master and duplicating a large amount by injection molding. In some cases, a stamper is manufactured. FIG. 1 is a schematic diagram of an injection molding machine.

[0003] 1 is a fixed mold, 2 is a movable mold, 3 is a stamper, 4 is a cavity, 5 is a nozzle, 6 is a heating cylinder,
7 is a screw, 8 is a motor, 9 is a hydraulic circuit and 10
Is a hopper. The resin raw material is stored in a hopper 10 and melted while being transferred by a screw 7 through a heating cylinder 6 to a nozzle 5 side.

In molding, the movable mold 2 is pressed with a weak force to move toward the fixed mold 1 to close the mold, and the movable mold 2 is pressed against the fixed mold 1 with a strong force to tighten the mold. Nozzle 5
Is brought into contact with the center hole of the fixed mold 1, the molten resin is injected into the mold through the hole to be solidified, and the movable mold 2 is separated from the fixed mold 1 to take out the solidified resin. Done in

[0005] The surface of the molded disk that was in contact with the fixed mold 1 was a mirror surface, and the surface that was in contact with the movable mold 2 on which the stamper 3 was mounted was the signal surface of the stamper 3 on which the signal pits were transferred. Has become. When the formed disk is a compact disk (hereinafter referred to as "CD"), a reflection film made of a metal such as aluminum is formed on a signal surface by a sputtering method or the like, and then ultraviolet rays are applied to protect the reflection film. A hard resin film such as a cured resin (hereinafter, referred to as “protective film”) is formed, and a label is printed on the protective film to form a CD. As a printing method of the label, a screen printing method using an ultraviolet curable ink is widely used.

On the other hand, the molded disk is a digital video disk (hereinafter referred to as "DVD"), which has one signal reading surface and records signals in two layers.
In this case, a DVD is obtained as follows. a) According to the molding process of the disk, the thickness is about 0.6
2 mm disks are formed.

B) One of the two disks (hereinafter referred to as "Lay
er0 substrate)). c) The other of the two disks (hereinafter “Layer
(referred to as “r1 substrate”). d) An ultraviolet curable resin is sandwiched between both signal surfaces of the Layer 0 substrate and the Layer 1 substrate, and the resin is cured by irradiating ultraviolet rays from the translucent layer side to bond the two substrates.

E) Layer 1 of the bonded disc
Print the label on the substrate. As a printing method of the label, a screen printing method using an ultraviolet curable ink is used similarly to the CD.

[0009]

However, in the conventional label printing method, which is a screen printing method using an ultraviolet curable ink, the disk is irradiated with ultraviolet light to cure the ink. And the disk itself warps due to the shrinkage of the ultraviolet curable ink.

The warpage of the disk does not occur so much because the thickness of the CD is relatively thick at 1.2 mm.
It does not degrade the playback characteristics of the disc,
The smaller the thickness of the disk itself, the greater the degree of warpage of the disk, and the more the reproduction characteristics deteriorate.
In addition, in the case of DVD, the aperture ratio of the lens is larger than that of the CD, so that the influence of the aberration due to the tilt of the disk with respect to the optical axis becomes remarkable, and even a slight warp of the disk greatly deteriorates the reproduction characteristics of the disk. The standard for warpage of CD is ± 1.6 °, whereas the standard for warpage of DVD is ± 0.8 °, which is very strict.

Therefore, in the case of a thin disk or a disk having a strict warpage standard such as a DVD, a screen printing method using a relatively inexpensive conventional ultraviolet curable ink may be adopted because the yield is deteriorated. There is a problem in that it is difficult and, in turn, must adopt another label printing method whose production cost is very high. The present invention has been made in order to solve the above-mentioned problems, and a method of manufacturing an information storage medium that does not warp a disk and has a low manufacturing cost as compared with a conventional label printing method. The purpose is to provide.

[0012]

According to a first aspect of the present invention, there is provided a method of manufacturing an information storage medium, comprising: a first mold and a second mold which can be separated into at least two parts; And a stamping sheet for holding a label material, the method for manufacturing an information storage medium for forming a label on a surface opposite to an information reading surface, the method comprising: A first step of separating the mold and the second mold, and a second step of disposing the stamping sheet between the first mold and the second mold separated by the first step. The first and second dies are combined, and the stamping sheet is disposed in the cavity surrounded by the first and second dies by the second step. The third step of positioning Filling the cavity with the resin serving as the base material of the information storage medium, and applying a heat of fusion and a molding pressure of the resin filled in the fourth step to the label material held by the stamping sheet. A second step of forming an information storage medium by curing the resin to which the label material has been transferred in the fifth step; and separating the first mold and the second mold. And a seventh step of taking out the information storage medium formed in the sixth step.

According to a second aspect of the present invention, in the method for manufacturing an information storage medium according to the first aspect, the information reading surface of the information storage medium taken out in the seventh step is: The method includes an eighth step of attaching at least one other information storage medium.
According to a third aspect of the present invention, in the method for manufacturing an information storage medium according to the first or second aspect, the information storage medium stores optically readable information. Characterized by being an optical disk.

[0014]

Embodiments of the present invention will be described in detail with reference to the drawings. However, the information storage medium manufactured by the present manufacturing method is not limited to an optical disk, but an optical disk will be described as an example for simplicity.
FIG. 2 is a schematic diagram of a main part of a manufacturing apparatus used in the method for manufacturing an information storage medium according to the present invention.

1 is a fixed mold, 2 is a movable mold, 3 is a stamper, 4 is a cavity, 11 is a stamping sheet, 12
Is a feed roller, 13 is a take-up roller, and 14 is a resin injection port. The resin mold shown in FIG. 2 is composed of a fixed mold 1 and a movable mold 2 that can be opened and closed. The movable mold 2 is moved to the fixed mold 1 side to join them. At this time, the resin mold is in a so-called closed state. At this time, the abutment surfaces of the fixed mold 1 and the movable mold 2 abut with each other, and the cavity 4 is formed in the central void.

In the drawing, a feed roller 12 and a take-up roller 13 for loading a stamping sheet 11 are attached to an upper portion and a lower portion of the fixed mold 1, and the stamping sheet 11 is movable with the fixed mold 1. The orientation is set between the molds 2. On the surface of the stamping sheet 11 facing the stamper 3, a label material is held in a laminated state. As described in detail below, the label material is transferred to the disk simultaneously with the molding of the disk. Has become.

Feed roller 12 and take-up roller 13
Is rotatable in a direction for moving the stamping sheet 11 from the top to the bottom of the drawing, and includes a fixed mold 1 and a movable mold 2.
In the process of turning from the closed state to the open state, the feed roller 12 and the take-up roller 13 simultaneously rotate, and feed the stamping sheet 11 wound therearound by a predetermined length. The structure is such that the roller 12 is wound around the winding roller 13.

In the manufacturing apparatus having the above-described structure, the disk is formed by moving the movable mold 2 to the fixed mold 1 and closing the movable mold 2 so that the fixed mold 1 and the movable mold 2 meet. Abut the cavity 4 formed centrally by their surroundings
Next, the resin material of the disk via a resin flow path (not shown) is injected from the resin inlet 14 while heating and pressurizing. For example, as a resin material of the disk, a PC (polycarbonate) resin, which is a thermoplastic resin, is used at an injection temperature of 3 ° C.
60 ° C., injection pressure 200 kg / cm ² and cavity 4
The liquid is pressure-filled under various conditions at a mold temperature of about 90 ° C.

However, such a resin material is not limited to a PC resin, but other materials having a high optical property such as a polymethyl methacrylate resin and an AS resin can be used. It is natural that the molding process is performed under the molding conditions that meet the conditions. Other light-transmitting materials include acrylate or methacrylate homo- or copolymers such as polymethyl methacrylate and polymethyl acrylate, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, polycarbonates, and the like. Thermoplastic resins such as polystyrene and polymethylpentene, or acrylates such as polyfunctional urethane acrylates and polyester acrylates cross-linked by ultraviolet rays or electron beams, transparent resins such as unsaturated polyesters, transparent ceramics such as transparent glass, etc. are used. Can be

When the filling is completed as described above, the resin material is cooled and held in the resin mold for a predetermined time period based on a cycle program determined by molding conditions matching the molding characteristics of the resin material, and the predetermined shape is formed. An optical disk is produced by molding. When the movable mold 2 is movably connected to the fixed mold 1 and the abutment surfaces of the respective molds are abutted and the fixed mold 1 and the movable mold 2 are closed, the stamping sheet 11 is fixed to the fixed mold. A surface where the label material of the stamping sheet 11 is laminated on a predetermined position of the cavity 4 formed by the mold 1 and the movable mold 2, that is, the surface of the stamper 3 opposite to the signal surface where the signal pits are transferred (hereinafter, “transfer surface”). ) Facing the signal surface. In this state, as described above, by filling the cavity 4 with the thermoplastic resin in a molten state under pressure, the optical disk is formed into a predetermined shape, and at the same time, the transfer surface of the stamping sheet 11 is processed and processed. A thin film of the label material is released from a release layer (not shown), and a thermal adhesive layer (not shown) or an undercoat layer (see FIG. (Not shown) while being hardened by cooling.

Thereafter, the fixed mold 1 and the movable mold 2 that have been closed are in an open state, the optical disk onto which the label has been transferred is taken out, and the feed roller 12 and the take-up roller 13 rotate synchronously. Thus, a new transfer surface of the stamping sheet 11 is set by winding the stamping sheet 11 of a predetermined length from the feed roller 12 side to the winding roller 13 side for the next molding.

The stamping sheet 11 for transferring the label material is usually made of a heat-resistant film sheet such as polyester having a thickness of about 10 μm to 100 μm on a release layer, a top coat layer, an ink layer, an undercoat layer, and a heat bonding layer. (All not shown) are sequentially coated and laminated by continuous processing such as a roll coater method. The structure of the optical disk, which has been subjected to the transfer processing at the same time as the molding by using the stamping sheet 11 for thermal transfer processed in this way, has a heat-adhesive layer and an undercoat layer on a light-transmitting substrate (such as PMMA resin). And an ink layer constituting the characters and graphics of the label and a top coat layer protecting the label from participating and corrosion.

As in the case of a CD or an LD (laser disk), a reflective layer is formed on the signal surface of the optical disk manufactured as described above, and a light-transmitting resin for protecting the reflective layer is overcoated. As a result, the optical disk of the single-sided reading single-layer recording system is completed with the label transferred. Next, a method of manufacturing an optical disk of a single-sided reading dual-layer recording system such as a DVD (hereinafter, referred to as a “single-sided dual-layer recording optical disk”) will be described. However, in this case, the recording is not limited to the two-layer recording, but may be an optical disk recorded over a plurality of layers.

In the manufacturing method according to the present invention, a single-sided dual-layer recording optical disk represented by a DVD is manufactured as follows. a) A disc having a thickness of about 0.6 mm with uneven pits formed on a signal surface according to a conventional disc molding process and having no label printed thereon (hereinafter referred to as “Layer”).
r0 substrate ").

B) A disc having a thickness of about 0.6 mm with a concavo-convex pit formed on the signal surface in accordance with the above-mentioned disc molding step and having a label printed at the same time as the molding (hereinafter referred to as a "Layer 1 base material") Is prepared. c) Form a translucent layer on the signal surface of the Layer 0 substrate. d) A reflective layer is formed on the signal surface of the Layer 1 base material.

E) An ultraviolet curable resin is sandwiched between the two signal surfaces of the Layer 0 base material and the Layer 1 base material,
The two substrates are bonded together by irradiating ultraviolet rays from the translucent layer side to cure the resin.

[0027]

As described above, according to the method for manufacturing an information storage medium according to the present invention, the label material is formed on the label surface of the information storage medium simultaneously with the resin molding by the injection pressure and the heat of fusion. By reducing the number of manufacturing steps, an information storage medium having a low manufacturing cost can be manufactured.

Further, according to the method of manufacturing an information storage medium according to the present invention, since a label is formed simultaneously with resin molding, there is a problem in a screen printing method using an ultraviolet curable ink which is a conventional label printing method. There is no "warping of the disk itself due to ultraviolet light",
It is possible to manufacture an information storage medium, such as a DVD, which greatly deteriorates reproduction characteristics even with a slight warpage of a disk.

[Brief description of the drawings]

FIG. 1 is a schematic view of an injection molding machine.

FIG. 2 is a schematic diagram of a main part of a manufacturing apparatus used in the method for manufacturing an information storage medium according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed mold 2 Movable mold 3 Stamper 4 Cavity 5 Nozzle 6 Heating cylinder 7 Screw 8 Motor 9 Hydraulic circuit 10 Hopper 11 Stamping sheet 12 Feed roller 13 Winding roller 14 Resin injection port

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshiaki Maeno 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (3)

[Claims] 1. A surface facing an information reading surface using a molding die composed of a first die and a second die that can be separated into at least two, and a stamping sheet holding a label material. A method for manufacturing an information storage medium for forming a label, comprising: a first step of separating a first die and a second die of the molding die; and the first die separated by the first step. A second step of arranging the stamping sheet between the first mold and the second mold, and a second step of arranging the stamping sheet between the first mold and the second mold. Inside the cavity surrounded by
A third step of positioning the stamping sheet arranged in the second step, and the cavity formed in the third step,
A fourth step of filling a resin serving as a base material of the information storage medium, and a fifth step of transferring a label material held by the stamping sheet to the resin by a melting heat and a molding pressure of the resin filled in the fourth step. A sixth step of curing the resin to which the label material has been transferred in the fifth step to form an information storage medium; and separating the first mold and the second mold to form the sixth step. 7. A method for manufacturing an information storage medium, comprising: a seventh step of taking out the information storage medium formed by the method. 2. The method according to claim 1, wherein at least one other information storage medium is attached to an information reading surface of the information storage medium taken out in the seventh step. A method for manufacturing an information storage medium, comprising: 3. The method for manufacturing an information storage medium according to claim 1, wherein the information storage medium is an optical disk on which optically readable information is recorded. A method for manufacturing a storage medium.