JP2001246643A - Recording medium, injection mold, injection molding machine and molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium wherein miaturization and an increase in capacity are achieved and the rotary center axes of both of an optical disk and an optical disk device are accurately aligned with each other, an injection molding machine and a injection molding method. SOLUTION: A positioning mechanism is further formed to a recording medium substrate having no through-hole and the rotary center axis with the optical disk is accurately aligned while a recordable region is magnified. By providing a hot runner in the injection molding machine and the injection molding method for this recording medium, the recording medium substrate having no through- hole is easily formed and a manufacturing process is simplified. A connection part for easily releasing a molded substrate from a mold without dropping the same from the injection molding machine is formed to an injection mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a recording medium, an injection mold and an injection molding machine, and a molding method, and more particularly to a recording medium having a novel shape, a mold for producing the same, and an injection molding machine. And a molding method. The present invention is suitable for, for example, next-generation small optical disks.

[0002]

2. Description of the Related Art In recent years, optical disks have been developed and put into practical use as large-capacity, high-density information recording media. Also,
Further large capacity is required to store image files and moving image files, and miniaturization of optical disks is required to improve portability. An optical disk is a recording medium that uses laser light for recording and / or reproducing data, and includes a magneto-optical disk. Such an optical disk is
Generally, it is used as an audio disk, a video disk, a large-capacity image file, and an auxiliary storage device of a computer.

A typical conventional optical disk has a through hole called a clamp at the center of the disk. Such a clamp unit is used by an optical disk device that records and / or reproduces an optical disk to fix and rotate the optical disk. Further, the clamp part can be divided into a through hole and a transparent part. In particular, the through hole is mainly used for fixing the optical disk, and the transparent portion is mainly used for holding. Such a clamp portion has also been used as a possible positioning mechanism for accurately positioning the rotation center axis of the optical disc and the rotation center axis of the optical disc apparatus. Therefore, the clamp section cannot be a recording area, but is a non-recording area. Also, the area occupied by the clamp portion cannot be generally reduced in proportion to the diameter of the optical disk even if the diameter of the optical disk is reduced. As a result, Japanese Patent No. 2692146 discloses a small-diameter optical disk without the above-mentioned clamp portion for the purpose of reducing the diameter without impairing the large capacity of the optical disk.

FIG. 17 shows a substrate shape of an optical disk having no above-mentioned through hole. FIG. 17 is a schematic sectional view showing the structure of a conventional optical disk substrate 110e. Here, the optical disk was embodied as an optical disk of a single-sided recording system. The optical disk includes, for example, a disk substrate 110e,
It has a recording layer and a protective film. Optical disk substrate 110e
Is a transparent disk-shaped substrate made of plastic, glass or the like. A recording surface is provided on the surface of the substrate 110e, and concentric or spiral guide grooves called grooves and concave portions called pits are formed on the recording surface. A recording layer and a protective film are sequentially formed on the upper surfaces of the grooves and the pits. As a result, the optical disk has a laminated structure including the disk substrate 110e, the recording layer, and the protective film.

An optical disk having no through hole has its outermost end held (clamped) by an optical disk device.
Had been rotated. Here, usually, when the eccentricity of the recording area is generated with respect to the rotation center of the disk substrate, the tracking by the optical disk device is not accurately performed. However, the optical disk having the optical disk substrate 110e is
Since the grooves and pits are formed at positions corresponding to the outer peripheral portion of the substrate 110e, there is a feature that the above-described tracking problem does not occur.

[0006]

According to the above-mentioned optical disk, since the outermost end is held by the optical disk device, the positioning accuracy between the center rotation axis of the optical disk and the center rotation axis of the optical disk device is improved. It was difficult to do. That is, since such an optical disk does not have a positioning mechanism, the track of the optical disk is eccentric and crosstalk occurs, which adversely affects recording and / or reproduction of the optical disk device. In addition, during high-speed reproduction, crosstalk is more likely to occur, so that the influence on the optical disk device is further increased. As a result, it has been difficult to reduce recording and / or reproduction failure of the optical disk device due to crosstalk or the like in the conventional optical disk having no through hole since it does not have a positioning mechanism.

[0007]

SUMMARY OF THE INVENTION Accordingly, it is a general object of the present invention to provide a new and useful recording medium, an injection mold and an injection molding machine, and a molding method for solving such a conventional problem. Aim.

More specifically, the present invention provides a recording medium, an injection mold and an injection molding machine, which are compact and have a large capacity, and in which the rotation center axes of an optical disk and an optical disk device coincide with each other with high precision. It is an exemplary object to provide a molding method.

In order to achieve the above object, a recording medium according to an exemplary embodiment of the present invention is a recording medium having a disk-shaped substrate having no through hole and a recording area provided on the substrate. The substrate is formed on a surface of the substrate opposite to the recording area, and has a function of connecting to a driving unit for driving the recording medium and a function of positioning a rotation center axis with the driving unit. It has a recess and holding means for preventing the substrate from dropping during injection molding. In such a recording medium, the center of rotation with the optical disk device can be accurately matched while allocating the area of the conventional through hole to the recordable area to increase the recording capacity.

An injection mold according to an exemplary aspect of the present invention includes a first mold and a second mold that cooperates with the first mold to define a molding cavity. A disk-shaped substrate having no through-hole, and a disk injection molding die for forming a recording medium having a recording area provided in the substrate, wherein the first die is provided with the recording medium. The first or second mold has a convex portion for forming a concave portion on the substrate having a function of positioning a rotation center axis with the driving portion together with a function of connecting with the driving portion for driving. Is provided with a connecting portion for forming holding means on the substrate for preventing the substrate from dropping when the first and second molds are opened. According to such a mold, it is possible to mold an optical disk having no through-hole and having the rotation center axis coincident with the optical disk device with high accuracy.

Further, an injection molding machine as one exemplary embodiment of the present invention has a first mold and a second mold which cooperates with the first mold to define a molding cavity. And a disk-shaped substrate having no through-hole, and an injection mold for forming a recording medium having a recording area provided in the substrate,
An injection molding machine having an injection unit that introduces a molten material into the cavity via a conveyance path, and a mold clamping mechanism that moves the first or second mold, wherein the first mold is A convex portion for forming a concave portion on the substrate having a function of connecting to a driving portion for driving the recording medium and a function of positioning a rotation center axis with the driving portion; The mold is provided with a connecting portion for forming a holding means for preventing the substrate from dropping when the first and second molds are opened. According to such an injection molding machine, the same operation as that of the above-mentioned injection mold is exerted.

[0012] A molding method as one exemplary embodiment of the present invention is a disk-shaped method having a first die and a second die facing the first die, and having no through hole. An injection molding die for forming a recording medium having a substrate and a recording area provided on the substrate; an injection unit for introducing a molten material into the cavity via a transport path;
A molding method using an injection molding machine having a mold clamping mechanism for moving a mold, wherein a step of forming a cavity by engaging a first mold and a second mold, A step of filling the molten material for forming the substrate through a transfer path, and a function of connecting to a drive unit for driving the recording medium by a convex portion provided in the first mold, A step of forming a concave portion having a function of positioning a rotation center axis with a driving portion on the substrate, and a connecting portion provided on the first or second mold, thereby forming a first portion.
Forming a holding means for preventing the substrate from dropping when the mold of the second mold is opened, cooling the inside of the cavity, and solidifying the molten resin; Opening the second mold and the second mold. Such a disk substrate molding method can exhibit the same operation as the above-described injection mold and injection molding machine.

Other objects and further features of the present invention will be made clear by the embodiments described below with reference to the accompanying drawings.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disc 100 as an exemplary embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a plan view of an optical disc 100 as an exemplary embodiment. FIG. 2 shows the optical disk 10 of FIG.
FIG. 3 is a cross-sectional view for explaining a laminated structure of No. 0; FIG. 3 is a cross-sectional view showing the shape of the optical disc substrate 110a having the first exemplary embodiment. FIG. 4 is a cross-sectional view showing the shape of the optical disk substrate 110b having the second exemplary embodiment.
FIG. 5 shows an optical disk substrate 11 having a third exemplary embodiment.
It is sectional drawing which shows the shape of 0c. FIG. 6 is a sectional view showing the shape of an optical disk substrate 110d having the fourth exemplary embodiment.

1 to 6 show, for example, a single-sided recording type rewritable optical disk 100 having a diameter of 50 mm or less.
The thickness of the substrates 100a to 100d is 0.6 mm or less. In each of the drawings, the same reference numerals indicate the same members, and a duplicate description will be omitted. In addition, the same reference numerals with alphabets generally indicate modified examples, and unless otherwise specified, reference numerals without alphabets are intended to collectively refer to all reference numerals with alphabets.

Referring to FIG. 1 and FIG.
00 denotes a substrate 110 and a positioning mechanism (recess) 120
, A holding unit 130, a recording layer 140, and a protective film 150.

As shown in FIG. 1, the optical disc 100
It has a data area 112 formed on a substrate 110. Further, depending on the recording method of the optical disc 100, a groove 114 and pits 116 (not shown) may be provided in the data area 112. For example,
The disc 100 can read information by irradiating the data area 112 with a laser beam and detecting the magnitude of the amount of reflected light that changes depending on the presence or absence of the pits 116. In addition, the optical disc 100 can have a management area for address information and the like. The management area is, for example, an area in which the head of the optical disk drive first accesses the optical disk 100, and is an area that the user cannot access. "Inaccessible" means that access is not possible when the user uses a normal optical disk device, for example, when the user modifies the optical disk device or uses the same equipment as the manufacturer It should be noted that this does not always mean that rewriting is impossible.

The data area 112 is an area that can be used by the user, and the optical disc 100 can use this area to record and / or reproduce video information, audio information, text information, software and other information (user data). it can. According to the optical disc 100 of the present invention, the data area 112 extends to the portion that was the conventional clamp portion, and the recordable area is larger than before.

The groove 114 is a concentric or spiral guide groove (recess). In addition, the protrusion between the guide grooves is called a land. The pit 116 is a concave portion mainly provided on a read-only optical disk, and is provided with a groove 114.
And / or formed on lands. Since the pits 116 reflect laser light differently depending on the presence or absence of the pits, information can be read by detecting the amount of reflected light. The information is represented by the length and interval of the pit 116. A row of pits 116 formed on the substrate 110 is called a track, and information is recorded along the track. The track pitch is usually about 1.5 μm, but the track is becoming narrower in order to increase the recording density.

Referring to FIG. 2, the optical disc 100 includes:
This is a laminate including a substrate 110, a positioning mechanism (recess) 120, a holding unit 130, a recording layer 140, and a protective film 150. The substrate 110 has optical characteristics such as high transmittance and low birefringence because laser light reciprocates during recording and reproduction. In this embodiment, the substrate 110 is made of, for example, a disc-shaped polycarbonate resin (PC) having a thickness of 0.6 mm or less, but is not limited thereto, and is a mixture of polycarbonate and acrylonitrile butadiene styrene. Transparent materials such as PC / ABS, acrylic resin (such as polymethyl methacrylate), glass, and polyolefin resin may be used. An information pattern (a signal surface on which information is recorded) of the data recording area 112 and the like is formed on the substrate 110 by a preformat. A recording layer 140 described later is formed on the information pattern.

The positioning mechanism (recess) 120
It is formed as part of zero. That is, the positioning mechanism 12
0 is formed simultaneously with the injection molding of the substrate 110. The positioning mechanism 120 is used for positioning the rotation center axis of the optical disk device and the rotation center axis of the optical disk. Further, the positioning mechanism 120 corresponds to a part of the area of the conventional clamp portion, and is also used as fixing means for being held and fixed by a driving mechanism 250 described later. In the present embodiment, the shape of the positioning mechanism 120 is embodied as a cylindrical concave portion. However, the shape is not limited to this, and a shape corresponding to the shape may be considered in consideration of the fitting with the driving mechanism 250 such as a tapered shape. Should be fine.

Substrate 110 having positioning mechanism 120
Is manufactured by an injection molding method. Substrate 11 of the present invention
In the case of 0, a pin gate 206 described later during injection molding is provided in the concave portion 120, and molding proceeds so as to have the groove 114 (and the pit 116) from the inner peripheral portion to the outer peripheral portion. Generally, a plastic substrate obtained by an injection molding method tends to have a large substrate birefringence at an inner peripheral portion. That is, the substrate is distorted as it approaches the inner peripheral portion where the injection gate 206 exists. Since such distortion greatly affects the information recording portion such as the groove 116, it becomes more difficult to maintain good recording / reproducing characteristics as it approaches the inner peripheral portion. However, in the present invention, since the pin gate 206 is provided closer to the center (inner peripheral portion) than in the prior art, it is possible to reduce the substrate birefringence generated in the inner peripheral portion. As a result, good recording / reproducing characteristics can be maintained even in the inner peripheral portion.

FIGS. 3 and 4 show the disk substrates 110a and 100b in which the stamper 230 is provided on the movable mold 220 and the positioning mechanism 120 is provided on the fixed mold 210 side. 5 and 6 show the disk substrates 110c and 100d in which the stamper 230 is provided on the fixed mold 210 and the positioning mechanism 120 is provided on the movable mold 220 side.
In addition to the positioning mechanism 120, the fixed disk 2 is not released from the fixed
It is desirable to provide a holding means 122 having a convex shape or a concave shape in order to prevent it from remaining on the upper surface 10. Since the holding unit 122 has an undercut shape, the holding unit 122 can draw the substrate 110 toward the movable mold 220 together with the opening of the movable mold 220. Further, the holding unit 122 can adsorb and hold the molded substrate 110 to the movable mold 220 by such a shape. Thus, the molded substrate 110 having the holding means 122 can be easily released from the fixed mold 210. Also,
When the mold is opened, it is possible to prevent the molded substrate 110 from dropping outside the mold.

The substrates 100a to 100d shown in FIGS.
According to this, the area that can be the data area 112 can be reduced to at least about half the area occupied by the conventional clamp unit. For example, the substrate 110 of FIGS.
5a and 5b, the regions excluding the portion where the auxiliary portion 122 is formed are the substrates 110c and 100d of FIGS.
It is possible to set almost the entire area as the data area 112.

The holding unit 130 records an optical disc and / or
Or, it is provided at the center of the optical disc to rotatably support the optical disc device when reproducing. However, depending on the optical disk device used, the holding unit 13
0 may be usable as the data area (recordable area) 112 in some cases. Therefore, depending on the optical disc device, it can be both a non-recording area and a recordable area. The holding unit 130 may be replaced by the positioning mechanism 120 described above.

The material used for the recording layer 140 depends on the recording method. In this embodiment, for example, a TbFeCo-based material protected by a dielectric layer is used.
An nSbTe-based material, a TbFeCo-based material, or the like can be alternatively used. The rewritable optical disc 100 used in this embodiment uses, for example, a phase change recording layer 140. The recording by the phase change is performed on the recording layer 1 in a crystalline state.
40 is irradiated with a relatively strong laser beam (for example, about 11 mW) for a short time to raise the temperature of the recording layer 140 to a high temperature (about 600 ° C.).
It is performed by quenching after ascending and melting. Due to the rapid cooling, the recording layer 140 becomes amorphous, and the reflectance decreases. The recording is erased by irradiating the recorded area with a laser beam of medium intensity (for example, about 6 mW), heating to a temperature slightly higher than the crystallization temperature, and gradually cooling to crystallize. . The reflectance is restored by crystallization. At the time of reproduction, the fact that the reflectance differs between the crystalline state and the amorphous state is used. At near-infrared wavelength, the crystal state is 2
It has a high reflectance of about 0%. The intensity of the laser beam during reproduction is about 1/10 of that during recording (for example, about 1.5 m
W). Also, a read-only optical disc 100
In such a case, it is not necessary to use the phase change or the like, so that (the formation of) the recording layer 140 can be omitted.

The protective film 150 is provided to protect the recording area. In this embodiment, the protective film 150 is made of an acrylic ultraviolet curable resin and has a thickness of about 10 μm. As another material of the protective film 150, for example, a transparent silicon-based or epoxy-based resin can be used.

The recording layer 140 and the protective film 150 are, for example,
It is formed by spin coating. Here, the spin coating method is a method in which a liquid material (the recording layer 140 or the protective film 150) is dropped on a substrate 150 rotating at a high speed, and the material is spread on the substrate using the centrifugal force. is there.
Since the optical disc 100 of the present invention has no through hole,
A liquid material can be dropped on the center of the optical disc 100,
It is possible to easily apply a uniform layer on the entire disk surface by spin coating. As a result, the high-quality recording layer 140 and the protective film 150 having a uniform thickness can be easily formed, and the cost and the working time can be reduced. In addition, in the formation of the thin film,
A sputtering method or the like is also used.

The above-described optical disc 100 has a read-only type, a write-once type, and erasable (rewritable) due to the difference in the recording method.
They are roughly divided into types. The read-only optical disk is a music C
D (CD-DA) and LD do not allow a user to write information, but once a master is manufactured, any number of copies can be made from it. Therefore, it is most suitable as a large distribution type media. Write-once C
In a DR (CD-recordable) or DVD-R, a method of forming a burn mark (pit) on a recording layer with a laser is used. This method is suitable for storing and storing important data because it is not possible to overwrite an area once recorded. CD-RW (CD-rewritable)
e) A rewritable type such as a DVD-RAM and a magneto-optical disk (MO) uses a phase change method or a laser beam and a magnetic field, and new information is repeatedly and repeatedly written in a once-recorded area. be able to.

Referring now to FIGS. 7 and 8, an injection molding machine 20 for molding the optical disk substrate 110 of the present invention.
0 will be explained. Here, FIG. 7 is a schematic sectional view of an injection molding machine 200 as an exemplary embodiment of the present invention. FIG.
FIG. 5 is an enlarged view of a main part of a movable mold 210 for forming a convex holding means 122a. FIG. 9 is an enlarged view of a main part of a movable mold for forming the concave holding means 122b. According to FIG. 7, the injection molding machine 200 includes a stationary mold 21.
0, a movable mold 220, a stamper 230, a resin transport section 240, a heating unit 250, and a release section 260.

The fixed mold 210 and the movable mold 220 are arranged to face each other. The fixed mold 210 has a male tapered surface, and the movable mold 220 has a female tapered surface.
However, the fixed mold 210 may have a female taper surface, and the movable mold 220 may have a male taper surface.
The engagement surfaces of the molds 210 and 220 are not limited to the tapered shape as in this embodiment. Also, the fixed mold 210
The fixed mirror surface 212 is used as a surface where the
And a movable mirror surface 222. An optical disk substrate molding cavity 204 is defined by cooperation of the two mirror surfaces 212 and 222 and an outer peripheral ring 202 described later. As described later, a stamper 230 is mounted on one of the fixed mirror surface 212 and the movable mirror surface 222. According to FIG. 7, the fixed mold 210 (fixed mirror surface 212) has a shape in which a central portion (fixed bush 218) protrudes to form the above-described positioning mechanism 120. However, such a protruding shape is not limited to the fixed mold 210 and may be formed on the movable mold 220 side.

Referring to FIG. 8 and FIG.
0 (on the ejector pin 266), a connecting portion 221a for forming the convex holding means 122a,
Alternatively, a connecting portion 122b for forming the concave holding means 122b is formed. More specifically, the connection unit 22
1a, the shape of a movable bush 228 described later is formed in a concave portion, and the concave portion is filled with resin, and a convex holding means 122a corresponding to the shape is formed. In the connecting portion 122b, a tip of an ejector pin 266 described later is formed in a convex shape, and a concave holding means 122b corresponding to the shape is formed. By the injection molding machine 200 having the mold 220 in which the connecting portion 122 is formed,
For example, the substrates 110a and 110b shown in FIGS.
Is molded. Substrate 110 on which holding means 122 is formed
When the holding means is protruded by an ejector pin 266 described later and is released from the movable mold 220,
The injection molding machine 20 is attracted to a take-out member (not shown) or the like.
0 is transported outside.

The fixed mirror surface 212 and the movable mirror surface 222
Are formed with temperature grooves 214 and 224 in which a temperature control medium is stored, so that the temperature inside the cavity 204 can be controlled. For example, the temperature grooves 214 and 224 can cool the molten resin in the cavity 204 by circulating cooling water. The temperature grooves 214 and 224 are all set at the same distance from the surface on which the cavity 204 is formed as shown in FIG. 7, and the volumes of the temperature grooves 214 and 224 are constant.

The fixed mold 210 is attached to the fixed platen 216,
The movable mold 220 is fixed to the movable platen 226, respectively. The movable platen 226 is penetrated by, for example, four tie bars 208 (not shown), and the movable platen can move relative to the fixed platen 216 along the tie bar 208. As a result, the movable mold 220
Can move relative to the fixed mold 210. As a moving mechanism of the movable platen 226, a desired mechanism such as a direct pressure type or a toggle type can be adopted.

The fixed mold 210 and the movable mold 220 have a fixed (mold) -side bush 218 and a movable (mold) -side bush 228, respectively. The fixed side bush 218 stores an air heat insulating material 251, a hot runner 253, and a hot runner heater 255. The movable bush 228 stores a positioning rod 232, an air groove 262 described later, and an ejector pin 266.

The stamper 230 is a mold having a concave and convex shape opposite to a desired product (replica: a record carrier to be mass-produced), and is made of a nickel (Ni) material or the like. The uneven portion of the stamper 230 is provided, for example, for forming a preformat signal or a data signal. In the present embodiment, the stamper 230 is fixed to the movable mirror surface 212, but is not limited thereto, and may be fixed to the fixed mirror surface 222. A method for fixing the stamper 230 will be described below. First, centering and positioning of the stamper 230 are performed using the positioning rod 232 provided at the center of the movable mold 220. Stamper 2 with fixed position determined
30 is vacuum-suctioned and fixed by the inner peripheral suction groove 234 and the outer peripheral suction groove 236. Such a fixing method has an advantage that the fixing and peeling of the stamper 230 are easy. Here, the positioning mechanism 120 formed on the disk substrate 110 of the present invention is formed on the surface opposite to the signal surface formed by the stamper 230.

The resin transport section 240 transports the molten resin M supplied from an injection unit described later into the cavity 204. Here, the resin transport section 240 has a cylinder nozzle 242 and a locate ring 244. In this embodiment, the cylinder nozzle 242 conveys the molten resin M from a heating cylinder (not shown) to a manifold 246 described later. Here, according to FIG. 7, the locate ring 244 is provided inside the movable mold fixing plate 226. Such a locate ring 244 is provided on the cylinder nozzle 242.
And the movable mold 220 and the movable mold fixing plate 226 are provided in order to accurately maintain the positional relationship.

The heating unit 250 can prevent the resin M from solidifying by maintaining the path of the molten resin M such as a spool and a runner at a high temperature. The heating unit 250 is called a hot runner system, and is most commonly used in a runnerless system. As shown in FIG. 7, the heating unit 250 is
51, a hot runner 253, a hot runner heater 255, a manifold 257, and a manifold heater 259.

The air heat insulating material 251 is a hot runner 25
1 and the fixed mirror surface 212 are brought into a non-contact state. This is to prevent the cooling effect of the temperature groove 214 from being transferred to the hot runner 251 and the hot runner heater 255 to solidify the resin M. In addition, the heater 255 for the hot runner and the heater 259 for the manifold can control the temperature of the molten resin M on the transport path at each position. After passing through the resin transport section 240, the molten resin M passes through the hot runner 25 via a manifold 246 whose temperature is controlled by a manifold heater 248.
Transported to 0. Thereafter, the conveyed molten resin M is filled into the cavity 204 via a gate 206 (not shown). As described above, by employing the hot runner method, it is no longer necessary to provide a cut punch and a scalpel cutter which have been conventionally used for forming the through hole.
Here, the gate 206 has a function of sealing the molten resin. Therefore, the gate 206 can be a boundary between the molten state and the solid state of the resin. In the present embodiment, the hot runner 250 is provided in the fixed mold 210. Alternatively, however, the extension nozzle may be used by extending the molding machine nozzle.

The release part 260 has a fixed (die) side air groove 262, a movable (die) side air groove 264, and an ejector pin 266. The fixed air groove 262 and the movable air groove 264 can release the disk substrate 110 formed at the time of opening the mold from the mirror surface 212 and the stamper 230. In addition, the ejector pins 266 drive out the formed disk substrate 110 and help the disk substrate 110 to be transported to the next apparatus. Referring to FIG. 9 again, the ejector pin 266 may be used at the distal end as the connection part 221b.

Hereinafter, a method for molding the optical disk substrate 110 by the injection molding machine 200 will be described with reference to FIGS. Here, FIG. 10 is a cross-sectional view showing the injection molding machine 200 before filling with the molten resin M. FIG. 11 is a sectional view showing the injection molding machine 200 after the injection of the molten resin M is completed. FIG. 12 is a sectional view showing the injection molding machine 200 when the mold is opened. FIG. 13 is a cross-sectional view showing the injection molding machine 200 when the molded substrate 110 is released from the mold. FIG. 14 is a schematic block diagram of an injection molding unit 200A having the injection molding machine 200. The injection molding unit 200A
In addition to the injection molding machine 200 described above, a control unit 270, a temperature control device 280, an injection unit 290, and a servomotor 295 for mold clamping are provided.

Before the injection molding, the fixed mold 210 and the movable mold 220 are adjusted to a predetermined temperature in advance. Further, the heating temperature of the molten resin in the injection unit is set to, for example, 360 ° C., and the temperature is adjusted. Further, the control unit 270 shown in FIG. 14 supplies a current (for example, a variable resistor or the like) supplied to the heating device so that the temperatures of the platens 216 and 226 become a predetermined temperature (both may be different temperatures or the same temperature). Using feedback control. Fixed platen 216
The temperature for adjusting the parallelism of the movable platen 226 and the movable platen 226 is preferably adjusted to the platen temperature at the time of performing the injection molding, and more specifically, a temperature in the range of 25 ° C. to 60 ° C. higher than the normal temperature. Fixed platen 216 and movable platen 2
When the temperatures of the 26 are different, the temperature difference is preferably within 15 ° C. Further, the platen parallelism adjustment temperature may have a temperature range of ± 5 ° C., preferably ± 2 ° C. at the same location. Here, the controller 270 is connected to a temperature controller 280, an injection unit 290, and a mold clamping servomotor 295, which will be described later, and controls these operations. However, one or more control units may be provided to control these operations.

The temperature controller 280 controls the temperatures of the platens 216 and 226 under the control of the controller 270. Temperature control device 280 includes platens 216 and 226.
A pipe is provided in the inside, and is constituted by a heating device such as a heater wire and cooling water. The heating device is composed of, for example, a heater wire wound around a pipe. The platen 21 is controlled by controlling the magnitude of the current flowing through the heater wire.
The temperature of the water flowing through the pipes in 6 and 226 can be adjusted. Other types of refrigerants (alcohol,
Galden, Freon, etc.) can be used. As a result, highly accurate alignment can be performed during mold clamping as shown in FIG.

According to FIG. 10, the fixed mold 210 and the movable mold 220 are clamped, for example, with a clamping pressure of 15 tons. A stamper 230 is mounted on the surface (mirror surface 222) of the movable mold 220 facing the fixed mold 210 by suction grooves 234 and 236. Then, the movable mold 220
And the fixed mold 210 are clamped to form the cavity 204.
To form Here, the stamper 230 has a thickness of 0.3
mm of pure nickel material, the surface of which has a U-shaped groove 114 having a track pitch of 0.8 μm, a width of 0.3 μm, and a depth of 0.2 μm and a preformat pattern such as an address pitch and servo pits 116 on an optical disk substrate. The unevenness to be formed on the surface of 110 is formed. The stamper 230 may be provided on either the fixed mold 210 side or the movable mold 220 side.

According to FIG. 14, the mold clamping is performed by a mold clamping servomotor 295. The mold clamping servomotor 295 is, for example, ROBOSH manufactured by FANUC.
Any motorized clamping mechanism known in the art, such as OT, can be applied. The control unit 270 can control the mold clamping force by controlling the number of revolutions of the servomotor and the current flowing through the motor, for example. Such a mold clamping mechanism is not limited to an electric type, and any mold clamping mechanism known in the art, such as a direct pressure mechanism using a hydraulic cylinder or a toggle mechanism using a magic hand, can be used.

A cavity 204 is formed, and a mold 210 is formed.
And 220 have reached the predetermined temperature, the injection unit 290 immediately injects the polycarbonate resin M heated and melted to 380 ° C. Here, the injection unit 290 has the same structure as that used in a normal injection molding machine, and includes a heating cylinder, a screw, a hydraulic cylinder (or a servomotor) and the like, not shown. The temperature of the heating cylinder, the number of rotations of the screw, and the hydraulic cylinder (or servomotor) can be controlled by the control unit 270 to control the emission power.

The molten resin M flows into the cavity 204 through the cylinder nozzle 242. As shown in FIG.
When the filling of the molten resin is completed, the resin is filled with the temperature grooves 21.
4 and 224 are cooled to the same temperature as the temperature control medium circulating. As a result, the disk substrate 110 is formed. At this time, when the supply of the resin ends, only the disk substrate 110 is formed by the hot runner 251. As a result, unnecessary solids are not formed on the disk substrate 110, so that the step of cutting off such portions can be omitted.

When the cooling is completed, the injection molding machine 200 opens the mold as shown in FIG. At the same time as the mold opening,
The fixed side air groove 262 blows out air at a predetermined pressure,
The forming substrate 110 is released from the fixed mold 210. Here, as described above, the disk substrate 110 of the present invention can be easily released from the fixed mold 210 without dropping from the injection molding machine 200 due to having the holding means 122. The mold opening is completed with the disk substrate 110 fixed to the stamper 230.

As shown in FIG. 13, the formed disk substrate 1
When the mold 10 is released from the injection molding machine 200, a movable air groove 264 and an ejector pin 266 are used. The movable air groove 264 blows out air having a predetermined pressure. In addition, at the same time, the substrate 110 is protruded by the ejector pins 266. Thereby, the holding means 122
Disk substrate 110 having a stamper 23
0 (movable mold 220).
The substrate 110 in the state shown in FIG. 13 is taken out of the injection molding machine 200 by a take-out device (not shown) or the like, and is conveyed to the next-stage device. In the next-stage apparatus, the recording layer 140 and the protective film 150 are formed. As a result, a laminated structure of the optical disc 100 as shown in FIG. 2 can be formed.

Hereinafter, the drive mechanism 250 of the optical disc 100 according to the present invention will be described with reference to FIG. FIG. 15 is a schematic sectional view showing the structure of a driving mechanism 250 as an exemplary embodiment of the present invention. The driving mechanisms 250 are respectively
It has a spindle 260 and a clamp 270. According to FIG. 15, the laser light passes through the objective lens 280 from below the optical disc 100 and is irradiated.

The spindle 260 is a member for holding and fixing the optical disc 100 from below, and is connected to a motor shaft of a motor (not shown). Therefore, when the spindle 210 rotates, the optical disc 100 rotates synchronously. According to FIG. 15, a holding section 262 and a fixing section 264 are provided at the tip of the spindle 260. The holding unit 262 hits and holds the disk 100. In order to hold the disk 100 with good stability, the holding unit 2
It is preferable to increase the contact area between 62 and disk 100. For example, according to FIG. 15, since the laser light is irradiated from below the optical disc 100, the objective lens 28
0 is also provided below the disk 100. In order to enlarge the recording area, the objective lens 280 must be able to move as close to the inner periphery as possible.
(Spindle 260) needs to be reduced. Holder 2
The reduction of 62 is achieved by making the contact surface between the holding section 262 and the optical disc 100 as close to the inner periphery as possible.

The fixing portion 264 has a convex shape as shown in FIG.
And fit. As a result, the center of the disc 100 and the center of the fixed part 264 coincide, and the
Eccentricity is prevented. Here, the eccentricity of the optical disk 100 has a problem that the laser light is deviated from the track when information is recorded, and the accuracy is lacking. The fixed part 264 enables accurate information recording. Further, the holding section 262 and / or
Alternatively, the fixing portion 264 may have a projection (not shown) because the disk 100 rotates without idling. Such projections are also provided on the optical disc 100, and the rotation of the motor can be transmitted to the disc using the engagement between the projections.

The clamp 270 is a member for holding the optical disk 100 between itself and the spindle 260. According to FIG. 15, the clamp 270 includes a retaining portion 272, a ball bearing 274, a ball receiver 276, and a leaf spring 2
78. The retaining portion 272 is made of metal or plastic (resin), and directly contacts the center of the optical disc 100. The fastening portion 272 is also provided for the optical disc 1.
Rotates in synchronization with 00.

Ball bearing 274 and ball receiver 2
76 is a member for rotating the optical disc 100 freely. Since the clamp 270 fixes the disk 100 by applying a force from the upper surface, if the applied force is too large, the rotation becomes difficult. Therefore, the rotation of the disk 100 is stabilized by providing the ball bearing 274 between the rotating retaining portion 272, the non-rotating force applying member (the plate spring 278 in this embodiment) and the ball receiver 276. . The leaf spring 278 is a force applying member. The force applied in the spindle direction by the leaf spring 278 is determined by the shape (sphere) of the ball bearing 274.
To overlap the rotation axis of the spindle 260. With these constituent members, the clamp 270 is
0 can be fixed and rotated with high precision.

The objective lens 280 can move up and down with the radius of the disk 100. The laser light must be converted to spot light when incident on the disk 100. For this purpose, the objective lens is provided between the laser irradiation port and the disc 100, and has a role of converting incident light into spot light. Also, make the light spot smaller,
In order to increase the recording density, the laser beam must be focused on the recording layer. Therefore, the objective lens 280
Can move up and down with respect to the surface of the disk 100 to form an appropriate focal point, and also follow a surface runout due to the rotation of the disk 100, so that it can be focused at an appropriate position. In FIG. 15, the objective lens 280 and the laser irradiation light are provided below the disk. However, the present invention is not limited to this, and may be provided above the disk.

Although the preferred embodiment of the present invention has been described above, the present invention can be variously modified and changed within the scope of the invention. For example, in the present embodiment, the description has been made with reference to the rewritable disc.
A write-once type may be used. Further, the rewritable disk may be, for example, a magneto-optical recording type.

Needless to say, the write-once type is not limited to the phase change type, but can be applied to a punch type, an alloy type, and a bubble type. Here, a punch type refers to a method in which a recording layer is melted with a laser beam, holes (pits) are formed in the recording layer by surface tension, signals are recorded, and a difference in reflectance between a holed portion and a flat portion is measured. A method of reproducing a signal by using the same. The recording layer is made of a Se—Te alloy film, a Te alloy (TeC, PbTeSb).
And organic dye films such as cyanine.
The alloy type refers to a method in which a multilayer film is alloyed with a laser beam to record a signal, and a signal is reproduced using a difference in reflectance between an alloy portion and a non-alloy portion, and a low oxide of Te (TeO) is used. _x ) or Sb-Se / Bi-Te can be used for the recording layer. The bubble type is a method of forming a bubble (bubble) in a recording layer by irradiating a laser beam, recording a signal, and reproducing a signal by utilizing a difference in reflectance between a bubble portion and a non-bubble portion. A two-layer film in which a film and a metal reflection film are stacked can be used for the recording layer.

Hereinafter, a schematic configuration of an optical disk device (removable memory drive) 300 as an exemplary embodiment compatible with the optical disk 100 and the movable mechanism 250 of the present invention will be described with reference to FIG. here,
FIG. 16 is a schematic block diagram of the optical disk device 300. The optical disk device 300 is configured as an optical disk drive connected to an external device 400 embodied as a personal computer in the present embodiment, and includes a control unit 270, a memory 320, a head 330, and a signal processing device 340. are doing. In addition, the driving device 300
Can have input means such as buttons and a keyboard, not shown, and display means such as a liquid crystal display.

The control unit 270 controls the operation of the head 330 and the signal processing device 340 under the control of the firmware stored in the memory 320. Here, “firmware” refers to software stored in the memory 320 regardless of the name. The firmware includes a utility program for formatting the optical disc 100, a utility program for reading the optical disc 100, a utility program for writing on the optical disc 100, and a security program for performing security management.

The utility program and the security program are programs supplied from the manufacturer of the optical disk device 300 or a company entrusted by the manufacturer. According to this embodiment, the user can use the normal format and the security format. The purpose of the security program is to prevent a user who does not have a proper right from accessing not only user data but also the optical disk 100. Details of the firmware processing will be described later.

The head 330 reads out the management data, security data and user data of the optical disc 100 and sends them to the signal processing device 340. However, as will be described later, when the security data is present on the optical disc 100, the head 330 according to the present embodiment controls the control unit 27 according to the firmware stored in the memory 320.
0, the security data or the management data is first extracted and subjected to a predetermined process, and then the external device 400 is allowed to access the user data. It is not supplied to the device 340. The signal processing device 340 is connected to the SCSI interface 412 of the external device 400, and can demodulate management data, security data, and user data to extract original information.

The external device 400 includes a PCI bus 410,
SCSI interface 412 and IDE bus 414
, A main memory 420, a control unit 430, a hard disk drive 440, a removable memory drive 450, a removable memory 452, and a display 460. Note that the removable memory 45
2 and 100, removable memory drives 450 and 30
0 may be the same.

The PCI bus 410, the SCSI interface 412, and the IDE interface 414 are well known in the art and will not be described in detail here. The main memory 420 includes, for example, a RAM and a ROM, and a program necessary for the operation of the control unit 430 is temporarily loaded from the hard disk 440 or an input from an input unit (not shown) such as a keyboard, a mouse, and a joystick. It is temporarily stored or stores information necessary for system operation. The control unit 430 controls the operation of each unit, and the hard disk 440 stores an OS such as Windows 98 and other programs (various drivers and the like) necessary for the operation of each unit. The removable memory drive 450 and the removable memory 452 can be used for recording and reproducing user data. The display is composed of, for example, a CRT display.

[0064]

According to the optical disc as an exemplary embodiment of the present invention, the recording area on the optical disc can be increased more than before by not providing a through-hole which is a non-recording area. Therefore, the rotation center axes of the optical disk device and the optical disk are accurately matched to each other, thereby preventing the recording and / or reproducing capability from being reduced.

According to the injection molding die, the injection molding machine, and the molding method as an exemplary embodiment of the present invention, by providing the hot runner, an optical disk having no through hole can be easily molded. Therefore, since the punching step using the cut punch can be omitted, the manufacturing process can be simplified. Further, since the connection portion for forming the holding means is formed in the injection mold, the molded substrate can be easily released from the mold without falling from the injection molding machine.

[Brief description of the drawings]

FIG. 1 is a plan view of an optical disc 100 as an exemplary embodiment.

FIG. 2 is a cross-sectional view of the optical disc 100 of FIG.

FIG. 3 shows an optical disc substrate 1 having a first exemplary embodiment.
It is sectional drawing which shows the shape of 10a.

FIG. 4 shows an optical disc substrate 1 having a second exemplary embodiment.
It is sectional drawing which shows the shape of 10b.

FIG. 5 shows an optical disc substrate 1 having a third exemplary embodiment.
It is sectional drawing which shows the shape of 10c.

FIG. 6 shows an optical disc substrate 1 having a fourth exemplary embodiment.
It is sectional drawing which shows the shape of 10d.

FIG. 7 shows an injection molding machine 2 according to an exemplary embodiment of the present invention.
It is a schematic sectional drawing of 00.

FIG. 8 is an enlarged view of a main part of a movable mold 210 for forming a convex holding means 122a.

FIG. 9 is an enlarged view of a main part of a movable mold for forming a concave holding means 122b.

FIG. 10 is a cross-sectional view showing the injection molding machine 200 before filling of the molten resin M.

FIG. 11 shows an injection molding machine 20 after the completion of injection of the molten resin M.
FIG.

FIG. 12 is a sectional view showing the injection molding machine 200 when the mold is opened.

FIG. 13 shows an injection molding machine 20 when the molded substrate 110 is released from the mold.
FIG.

FIG. 14 is a schematic block diagram of an optical disc device 300.

FIG. 15 shows a driving mechanism 2 as an exemplary embodiment of the present invention.
It is a schematic sectional drawing which shows the structure of 50.

FIG. 16 is a schematic block diagram of an optical disc device 300.

FIG. 17 is a sectional view showing the structure of a conventional optical disk substrate 110e.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 optical disk 110 substrate 120 positioning mechanism (recess) 130 holding unit 140 recording layer 150 protective film 200 injection molding machine 200A injection molding unit 210 fixed mold 220 movable mold 230 stamper 240 resin transport unit 250 heating unit 260 release unit 270 control Unit 280 Temperature control device 290 Injection unit 295 Servo motor for mold clamping 300 Optical disk device (removable memory drive) 310 Control unit 320 Memory 330 Head 340 Signal processing device 400 External device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) G11B 7/26 511 G11B 7/26 511 521 521 // B29L 17:00 B29L 17:00 (72) Inventor Koji Takasawa 1-88 Ushitora, Ibaraki-shi, Osaka Prefecture, Hitachi Hitachi, Ltd. (72) Inventor Koichi Otsuka 1-188 Ushitora, Ibaraki-shi, Osaka Prefecture, Hitachi Hitachi Ltd. 1-88 Ushitora, Ibaraki-shi, Osaka F-term (reference) in Hitachi Maxell, Ltd. 4F202 AA28 AG19 AH79 CA11 CB01 CK03 CK32 CN01 CN21 4F206 AA28 AG19 AH79 JA07 JN41 JQ69 JQ81 5D029 KB01 KB12 KB15 KB20 PA05 5D121 AA DD DD18 DD20 GG24 JJ02

Claims (14)

[Claims] 1. A recording medium having a disk-shaped substrate having no through-hole and a recording area provided on the substrate, wherein the substrate is formed on a surface of the substrate opposite to the recording area. A recording unit having a function of connecting to a driving unit for driving the recording medium, a function of positioning a rotation center axis with the driving unit, and a holding unit for preventing the substrate from dropping during injection molding. Medium. 2. The recording medium according to claim 1, wherein the recording medium is an optical disk for recording and / or reproducing information by light. 3. The recording medium according to claim 1, wherein said holding means is formed on the same surface as said recording area. 4. The recording medium according to claim 1, wherein said holding means is formed in said recess. 5. The recording medium according to claim 3, wherein said holding means has a convex or concave shape. 6. A disk-shaped substrate having a first mold, a second mold defining a molding cavity in cooperation with the first mold, and having no through-hole; A disk injection molding die for forming a recording medium having a recording area provided on a substrate, wherein the first die has a function of connecting to a driving unit for driving the recording medium, A convex portion for forming a concave portion having a function of positioning a rotation center axis with a driving portion on the substrate, wherein the first or second mold is a mold of the first and second molds; An injection mold provided with a connection portion for forming a holding means for preventing the substrate from dropping when opened on the substrate. 7. The injection molding die according to claim 6, wherein when the connection portion is provided on the first mold, the connection portion is provided on the projection of the first mold. 8. The injection molding die according to claim 6, wherein said connecting portion has a convex or concave shape. 9. A disk-shaped substrate having a first mold, a second mold that defines a molding cavity in cooperation with the first mold, and having no through-hole; An injection mold for forming a recording medium having a recording area provided on a substrate; an injection unit for introducing a molten material into the cavity via a conveyance path; and moving the first or second mold. An injection molding machine having a mold clamping mechanism, wherein the first mold has a function of connecting to a drive unit for driving the recording medium and a function of positioning a rotation center axis with the drive unit. The first or second mold has a holding means for preventing the substrate from dropping when the first and second molds are opened. An injection molding machine provided with a connection part for forming on a substrate. 10. The injection molding for a disk according to claim 9, wherein when the fitting portion is provided on the first mold, the fitting portion is provided at the center of the convex portion of the first mold. Mold. 11. The injection molding machine according to claim 9, wherein the joining portion has a convex or concave shape, and the fitting portion has a concave or convex shape fitted to the joining portion. 12. The injection molding machine according to claim 9, wherein said injection molding machine further comprises a heating unit of a hot runner type or an extension nozzle type. 13. A disk-shaped substrate having a first die, a second die facing the first die, and not having a through hole, and a recording area provided on the substrate. An injection molding die for forming a recording medium having: an injection unit for introducing a molten material into the cavity via a transport path; and a mold clamping mechanism for moving the first or second die. A molding method using a molding machine, comprising: a step of forming a cavity by engaging a first mold and a second mold; and a conveying path of the molten material for molding the substrate in the cavity. And a function of connecting to a drive unit for driving the recording medium by a protrusion provided on the first mold, and a function of positioning a rotation center axis with the drive unit. Forming a recess in the substrate; Or a step of forming holding means for preventing the substrate from dropping when the molds of the first and second molds are opened on the substrate by a connecting portion provided in the second mold, and cooling the inside of the cavity, A molding method, comprising: a step of solidifying a molten resin; and a step of opening the first mold and the second mold. 14. The molding method according to claim 13, further comprising a step of heating the transport path by a hot runner type or extension nozzle type heating unit to prevent the molten material from solidifying.