JP2005063573A - Manufacturing method of optical disk medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the manufacturing efficiency of an optical disk medium in a manufacturing method of the optical disk medium wherein data are recorded and/or reproduced by an optical system and a magneto-optical system. <P>SOLUTION: The manufacturing method of the optical disk has a step for laminating at least a data recording layer 7, a reflection layer 8 and a protective film 9 on each of a plurality of parts of at least one surface of one large-sized metal substrate 50 to simultaneously work a plurality of optical disk mediums and a step for simultaneously pressing the plurality of optical disk mediums to simultaneously manufacture the plurality of optical disk mediums. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing an optical disc medium for recording and / or reproducing data by an optical method or a magneto-optical method.

As is well known, an optical disk medium such as an optical disk or a magneto-optical disk that records and / or reproduces data by an optical method or a magneto-optical method has a data recording layer such as an optical pit or a magnetic film on one or both sides of the disk substrate. A transparent protective layer is coated on the data recording layer.
In general, this optical disk medium is inserted into the outer periphery of the centering convex portion on the turntable by a center hole, chucked and rotated, and data is recorded on the data recording layer by a light beam or magneto-optical. Recording and / or reproduction is performed.

A magnetic disk that records / reproduces data with a magnetic head usually uses a metal substrate as a disk substrate, and a magnetic film is formed on the surface of the metal substrate. A general method for manufacturing a magnetic disk is to inject and mold a molten metal material such as a magnesium alloy into a mold cavity to solidify the metal substrates one by one. After a center hole is punched out at the center, a magnetic film is formed on the surface (one side or both sides) of the metal substrate by sputtering or the like (for example, Patent Document 1).
JP-A-11-345412

  The problem to be solved is that in the method of manufacturing magnetic disks one by one, the manufacturing (production) efficiency is very low and the manufacturing cost is high. In addition, in an optical disc medium in which a center hole is formed in a metal substrate, the area of a data recording area or an area for displaying pictures / characters is limited.

  The present invention can improve the manufacturing (production) efficiency of an optical disk medium using a metal substrate, and greatly expand the data recording area of the optical disk medium and the display area for pictures, characters, etc. In the method of manufacturing an optical disk medium in which a data recording layer, a reflective film, and a protective film are laminated on at least one side of the optical recording medium, the data recording layer, the reflective film, and the protective film are respectively formed on at least one side of a single large metal substrate. A step of simultaneously processing a plurality of small optical disc media by laminating a film, and a step of simultaneously pressing the plurality of small optical disc media from the large metal substrate; and on at least one surface of the metal substrate. In the method of manufacturing an optical disc medium in which a picture / character layer, a data recording layer, a reflective film, and a protective film on which pictures and characters are drawn / printed are laminated, Laminating the picture / character layer, the data recording layer, the reflective film, and the protective film on each of a plurality of locations on at least one side of a large metal substrate, and simultaneously processing a plurality of small optical disc media; And a step of simultaneously pressing an optical disk medium from the large metal substrate.

  The method for producing an optical disk medium of the present invention can simultaneously produce a plurality of small optical disk media from a single large metal substrate, so that the production (production) efficiency of the optical disk medium is remarkably improved and the cost of the optical disk medium is significantly increased. Down can be realized.

  The purpose of enlarging the data recording area of the optical disk medium and the display area for pictures, characters, etc. is the center of each small optical disk medium when processing multiple small optical disk media on a large metal substrate during the production of the optical disk medium. This was realized by effectively utilizing the entire occupied area of each small optical disk medium without processing the hole.

  The purpose of simultaneously forming a protective layer on the reflective films of a plurality of small optical disk media by spin coating was realized by controlling the rotation in a horizontal plane around the central hole of the large metal substrate.

  When controlling rotation in a horizontal plane around the center hole of the large metal substrate, the purpose of balancing the rotation of the large metal substrate is to be substantially opposite to the positioning holes formed near the outer periphery of the large metal substrate. This was realized by a balancing hole formed near the outer periphery of the large metal substrate.

  For the purpose of efficiently producing a plurality of small optical disk media simultaneously from a single large metal substrate, by setting a plurality of small optical disk medium processing regions arranged in a ring around the rotation center of the large metal substrate, This was realized by processing a small optical disk medium in the plurality of small optical disk medium processing areas, and cutting the plurality of small optical disk medium processing areas simultaneously from the large metal substrate by press working after the processing.

  Simultaneously press in the processing area of multiple small optical disc media to prevent the spin coating material from forming a bulge on the outer periphery of the protective film spin-coated on the reflective film in the processing area of multiple small optical disc media When manufacturing a plurality of small optical disk media by processing, this was realized by pressing a position displaced by 2 mm or more inward from the outermost peripheral position of these small optical disk medium processing regions.

  For the purpose of simultaneously manufacturing six small optical disk media from one large metal substrate, the large metal substrate has a diameter of approximately 120 mm, and the small optical disk medium processing region arranged in a ring shape has a diameter of approximately 53 mm or less. Realized by forming into.

Description of optical disk medium manufacturing method

First, an embodiment of an optical disk medium manufacturing method of the present invention will be described with reference to FIGS.
FIG. 1 shows an embodiment in which a plurality of, for example, six small (small-diameter) optical disc media 1 are manufactured simultaneously from a single disk-shaped large (large-diameter) metal substrate 50.
Therefore, a circular center hole 51 or the like is formed at the center of the large metal substrate 50, and six circular small optical disk medium processing regions 52 are arranged at equal intervals (six equally arranged) on the outer periphery of the center hole 51. ) Is arranged in a ring shape. Each of the six small optical disk medium processing regions 52 is configured such that the small optical disk medium 1 is processed substantially concentrically.

  At this time, in terms of dimensions, for example, the diameter D1 of the large metal substrate 50 is configured to be approximately 120 mm, and the diameter D2 of the center hole 51 is configured to be approximately 15 mm. And the diameter D3 of the six small optical disk medium processing areas 52 is configured to be 53 mm or less, and the diameter D4 of the small optical disk medium 1 is 30 mm. Accordingly, there is a difference of 23 mm or less between the diameter D3 of the small optical disk medium processing area 52 and the diameter D4 of the small optical disk medium 1, and the small optical disk medium 1 is processed almost concentrically in the small optical disk medium processing area 52. Therefore, an empty space having a width W1 of 11.5 mm or less exists between the small optical disk medium processing region 52 and the outermost periphery of the small optical disk medium 1.

  In the vicinity of the outer peripheral portion of the large metal substrate 50, there is one positioning hole 53 made of a hole or notch and one or more balancing holes 54 made of a hole or notch or the like. 51 is formed symmetrically. The center hole 51 and the positioning hole 53 are used so as to serve as a positioning reference and a rotation reference for the large metal substrate 50 at the time of injection processing or spin coating, which will be described later. Further, the balancing hole 54 is a rotational balance (the positioning hole 53 is displaced from the center hole 51) when the large metal substrate 50 is controlled to rotate around the center hole 51 in a horizontal plane during spin coating described later. To correct the rotational balance of the large metal substrate 50 lost by being formed in the formed position). Therefore, one balancing hole 54 having the same shape as the positioning hole 53 may be formed at a line symmetrical position with the positioning hole 53 with the center hole 51 interposed therebetween. Two balancing holes 54 may be formed at point-symmetric positions with the center hole 51 in between.

  Next, a method of manufacturing six small optical disk media 1 using one large metal substrate 50 will be described with reference to FIGS. At this time, the six small optical disk media 1 may be single-sided disks as described later, but here, a method for manufacturing a double-sided disk as described later will be described. 2 to 5 are schematic views showing the thickness direction in an enlarged manner in order to clarify the structure.

First, as shown in FIG. 2, for example, SUS430 (magnetic stainless steel material) having a thickness T1 of 0.5 mm or less (see FIG. 3) can be applied to the large metal substrate 50.
Then, on both sides of the large metal substrate 50, on the central side in the six small optical disk medium processing areas 52, as will be described later, a picture / character layer 6 in which pictures / characters are drawn / printed in advance is respectively formed. Has been.

  Further, as shown in FIG. 2, between the pair of molds 61 and 62 of the injection molding machine 60, the positions are respectively opposed to the six small optical disk medium processing regions 52 of the large metal substrate 50 shown in FIG. Six hollow cavities 63 having a shallow cylindrical shape are formed. Each of the six cavities 63 has a diameter of 53 mm or less, which is the same as the diameter D3 of the six small optical disk medium processing regions 52 of the large metal substrate 50.

  Therefore, as shown in FIG. 2, the large metal substrate 50 is mounted between a pair of molds 61 and 62 of the injection molding machine 60, and the large metal substrate 50 is arranged in the thickness direction of the six circular cavities 63. The picture / character layer 6 formed in advance in six locations of the large metal substrate 50 is set so as to cross the center position, and is positioned at the center positions of the six cavities 63, respectively.

  At this time, for example, the center hole 51 of the large metal substrate 50 is inserted into the center pin 64 of one mold 61, and the positioning hole 53 of the large metal substrate 50 is inserted into the positioning pin 65 of the one mold 61. Thus, the large metal substrate 50 is positioned with respect to the six cavities 63. The other mold 62 is also engaged with the center pin 64 of one mold 61 by the center hole 66, and positioning with respect to the one mold 61 is performed by other positioning means (not shown).

  On the other hand, as shown in FIG. 2, the opposing surfaces 61a and 62a in the thickness direction in the six cavities 63 of the pair of molds 61 and 62 have a concavo-convex shape of about 50 to 130 nm as data (signal) 7a. The concavo-convex portions 67 and 68 for forming pits for forming are processed in advance.

  Therefore, as shown in FIG. 2, molten resin of transparent resin (for example, PC (polycarbonate)) is injected from the injection gates 69 and 70 of the pair of molds 61 and 62 into the six cavities 63 of the large metal substrate 50. Injected onto the picture / character layer 6 on both sides in the six small optical disk medium processing areas 52 simultaneously, and a pair of concavo-convex shapes 67 and 68 form concavo-convex pits of about 50 to 130 nm as data 7a on the surface. The paired data recording layers 7 are simultaneously subjected to outsert molding (injection molding) in the six small optical disk medium processing regions 52 shown in FIG. 1 on the surface of the picture / character layer 6 on both sides.

  Then, after cooling the pair of data recording layers 7 made of the transparent resin layer, the pair of molds 61 and 62 are released, and the large metal substrate 50 is taken out of the injection molding machine 60. Through the above steps, as will be described later, the molding process of the data recording layer 7 having a light transmittance of 10 to 20 μm or more is completed.

  Next, as shown in FIG. 3, as described later, a pair of reflective films 8 that are light-transmitting thin films with a thickness of about 10 to 20 nm are formed into six small optical disk mediums of a large metal substrate 50 On the surface of the data recording layer 7 on both sides of the region 52, one surface is sequentially formed by sputtering.

  Next, as shown in FIG. 4, as will be described later, the protective film 9 made of a transparent UV resin material or the like is formed on the surface of the reflective film 8 on both sides of the six small optical disk medium processing regions 52 of the large metal substrate 50. Are sequentially formed on each side by spin coating.

  At this time, the large metal substrate 50 is rotationally driven around the center hole 51 at a high speed in a horizontal plane by a rotating means (not shown), and the rotation balance of the large metal substrate 50 lost by the positioning hole 53 is balanced by the balancing hole 54. As described above, the large metal substrate 50 can be stably rotated at a high speed with a stable rotation balance.

  On the other hand, as shown in FIG. 4, due to the centrifugal force at the time of spin coating of the protective film 9, the protective film 9 is placed in the outermost peripheral area on both surfaces of the six small optical disk medium processing areas 52 within a width W of 2 mm or less. Swelled part 15 naturally occurs.

  Therefore, finally, as shown in FIG. 5, the inside of the six small optical disk medium processing regions 52 having a diameter D3 of one large metal substrate 50 of 53 mm or less is circularly formed with a diameter D4 by a press machine, The six small optical disk media 1 having the diameter D4 of 30 mm are simultaneously cut out by pressing almost concentrically, thereby completing the manufacture of the six small optical disk media 1.

According to the manufacturing method of the small optical disk medium 1 as described above, the protective film is formed in the outermost peripheral area of the six small optical disk medium processing areas 52 within the width W within 2 mm during the spin coating shown in FIG. Although the 9 raised portions 15 naturally occur, as shown in FIG. 5, at the time of pressing, the diameter D4 is 30 mm inside the six small optical disk medium processing regions 52 having a diameter D3 of 53 mm or less. By pressing the small optical disk medium 1 substantially concentrically, the bulging portion 15 of the protective film 9 having a width W of 2 mm or less becomes the outermost peripheral area W1 = 11.5 mm in the six small optical disk medium processing areas 52. In the state where it is left in each of the open spaces, the inside is pressed to a diameter D4 = 30 mm.
Therefore, the raised portion 15 of the protective film 9 does not exist at all in the outermost peripheral area of the six small optical disc media 1 manufactured in this way.

Therefore, according to the method for manufacturing an optical disk medium of the present invention, six small optical disk media 1 in which the raised portion 15 of the protective film 9 does not occur (exists) at the outermost peripheral portion can be simultaneously manufactured with high accuracy.
Further, the six small optical disc media 1 manufactured by the optical disc medium manufacturing method of the present invention are optical disc media having no center hole.

Description of optical disc apparatus for reproducing small optical disc media

First, the outline of the main part of the optical disk apparatus for reproducing the small optical disk medium of the present invention will be described with reference to FIG.
The small optical disk medium 1 of the present invention reproduces (reads) data by a light beam represented by CD and DVD. However, there is no denying that data is recorded and / or reproduced (read) by a magneto-optical method such as MO. Although details of the small optical disk medium 1 will be described later, a metal substrate made of a magnetic material is used for the disk substrate of the small optical disk medium 1. A disk substrate of a general optical disk medium is PC (polycarbonate).

Next, a turntable 3 is fixed to the tip of the motor shaft 2a of the spindle motor 2 by press-fitting, bonding, screwing or the like, and details of the turntable 3 will be described later. It consists of
The turntable 3 is magnetized with N and S poles in the thickness direction so that the small optical disk medium 1 is attracted (fixed) on the disk mounting surface 3a of the turntable 3 by the magnetic force MF. It is configured.

The small optical disk medium 1 is rotated integrally with the turntable 3 by a spindle motor 2, and data (signal) recorded concentrically on one or both surfaces of the small optical disk medium 1 is irradiated from the optical pickup 4. It is read (reproduced) by a laser beam LB which is a beam.
At this time, unlike the general optical disk medium, the small optical disk medium 1 of the present invention does not have a center hole as will be described in detail later, and covers a wide range from the outer periphery to the center of the small optical disk medium 1. Since data is recorded over this, the optical pickup 4 reads the data while accessing the small optical disk medium 1 in the radial direction (arrow Aa, b direction) over a wide range from the outer periphery to the center.
At this time, since the turntable 3 exists on the entire lower surface side of the small optical disk medium 1, the optical pickup 4 reads data from the upper side opposite to the turntable 3 of the small optical disk medium 1.

Next, the details of the small optical disk medium 1 of the present invention will be described with reference to FIGS. 7 is a cross-sectional view illustrating details of the small optical disk medium 1 on which data is recorded on only one side, and FIG. 8 is a cross-sectional view illustrating details of the small optical disk medium 1 on which data is recorded on both sides. .
Therefore, the disk substrate of the small optical disk medium 1 is composed of a metal substrate 5 made of a magnetic material such as a thin metal disk. For example, SUS430 (a stainless steel material having magnetism) having a thickness of 0.5 mm or less can be applied to the metal substrate 5.

  A picture / character layer 6 on which a picture or a character is drawn / printed is formed on one side or both sides of the metal substrate 5. Further, a data recording layer 7 made of a transparent resin layer is formed on the picture / character layer 6. In this data recording layer 7, data (signals) 7a are formed concentrically in a concavo-convex shape called a pit having a depth of about 50 to 130 nm. Although FIG. 7 and FIG. 8 schematically show the concavo-convex shape, which is the data 7a, in practice, the shape of the data 7a is so small that it can hardly be identified with the eyes. It is something that looks flat at first glance. The pits are the same as those used for ROM disks such as CDs and DVDs, and are general signal recording information for optical disks.

  As described above, the data recording layer 7 is formed simultaneously with the data 7 a by the injection molding machine 60 by the transparent resin layer injection-molded on the picture / character layer 6. The thickness T of the data recording layer (= transparent resin layer) 7 at this time is 20 μm or more.

Further, in this small optical disc medium 1, a reflective film 8 capable of transmitting light from the data recording layer 7 (on the pit surface) by a sputtering method is formed. Examples of the material of the reflective film 8 include aluminum, an aluminum alloy, silver, a silver alloy, and silicon.
The reflection film 8 is a thin film having a thickness of about 10 to 20 nm, and functions as a reflection film for a laser beam LB irradiated from an optical pickup 4 described later while maintaining the pit shape of the data recording layer 7.

Since the reflection film 8 is a thin film, the reflection film 8 is a film having a partial light transmittance with a reflectance of about 10 to 30%.
Therefore, the picture and characters of the picture / character layer 6 formed on the surface of the metal substrate 5 can be viewed through the reflective film 8.

  A protective film 9 that is a cover coat made of a transparent UV resin material or the like is formed on the reflective film 8. The protective film 9 is formed into a thin film by a spin coating method and is cured by UV (ultraviolet) irradiation.

  As shown in FIG. 9, the optical pickup 4 described later irradiates a laser beam LB from the protective film 9 side of the small optical disk medium 1 through the objective lens 4a. The laser beam LB that has passed through the protective film 9 is reflected by the reflective film 8 and returns to the optical pickup 4. The recorded signal can be read by the change in the amount of reflected light due to the pits in the data recording layer 7. This is the same principle as CD and DVD.

  The small optical disk medium 1 of the present invention has a feature that the small optical disk medium 1 itself is attracted to a magnet because the disk substrate is formed on a magnetic metal substrate 5. Conventional optical disk media, for example, use a metal piece called a magnet called a hub attached to a disk for MD (mini disk), or a disk fixing mechanism such as a disk clamper for CD or DVD. . However, according to the present invention, a magnet attracting hub, a disc clamper and the like are not required, and the small optical disc medium 1 can be attracted to the disc mounting surface 3a by the magnetic force MF of the turntable 3 alone.

  That is, as shown in FIG. 12, the turntable 3 is magnetized at the position corresponding to the disk mounting surface 3a of the turntable 3 made of a magnetic material so that the north and south poles are directed vertically. Is formed into a magnet. Then, since the metal substrate 5 of the small optical disk medium 1 is attracted to the turntable 3 side by the magnetic force MF of the magnet, the small optical disk medium 1 is attracted horizontally (parallel) onto the disk mounting surface 7a of the turntable 3. can do.

At that time, the entire metal substrate 5 of the small optical disk medium 1 is adsorbed in parallel on the disk mounting surface 7a of the turntable 3, so that the warp of the small optical disk medium 1 is corrected and the plane of the entire small optical disk medium 1 is corrected. The degree is significantly improved.
Therefore, when the data pickup layer 7 is irradiated with the laser beam LB by the optical pickup 4 and the reflected light is read, the focus error can be reduced, and the data can always be read with high accuracy.

  In addition, since the metal substrate 5 is used for the disc substrate as compared with the conventional optical disc medium in which the disc substrate is made of PC (polycarbonate) such as general CD and DVD, the rigidity of the small optical disc medium 1 as a whole. Goes up. This produces an advantage that the thickness of the entire small optical disk medium 1 can be reduced as compared with equivalent disk rigidity.

  When the optical pickup 4 performs signal reproduction, it is desired to read only the light reflected by the reflective film 8. However, since the reflecting film 8 is a partially transmissive reflecting film, the transmitted light generates unnecessary reflected light in the picture / character layer 6.

  For this reason, in the present invention, unnecessary reflected light is reduced by increasing the thickness T (= the distance between the picture / character layer 6 and the reflective film 8) of the transparent resin layer (data recording layer 7) (FIG. 9). The laser beam LB focused on the reflective film 8 is diffused on the picture / character layer 6 and projected with a larger light diameter as the transparent resin layer (data recording layer 7) is made thicker. The Therefore, the amount of unnecessary reflected light Lb2 reflected by the picture / character layer 6 leaks into the necessary reflected light Lb1 reflected by the reflective film 8, and the data reading accuracy is remarkably improved. can do.

  Taking a two-layer recording disk actually used in a DVD or the like as an example, reproduction is possible with a distance of 20 μm between the first and second layers of the reflective film. As long as an interval of at least 20 μm is provided, even if unnecessary reflected light from another layer exists, the system has a proven track record. The reflective film 8 is partially transparent, and the transparent resin layer (data recording layer 7) is thickened to a level at which unnecessary reflected light Lb2 from the picture / character layer 6 does not cause a problem (20 μm or more). ) Makes it possible to print pictures and characters on the signal recording side of the disc. In the prior art, printing was possible on the back surface of the signal recording surface, but it was impossible to print on the signal recording surface side.

Further, as another feature of the small optical disk medium 1 of the present invention, the disk surface is covered with a protective film 9 which is a protective layer, so that the disk surface has no shape irregularities and the disk surface is formed into a smooth surface. What you can do. As shown in the overall disk diagram of FIG. 6, it can be mentioned that there is no center hole (hole at the center of the disk).
In the conventional optical disk medium, a center hole for performing centering is indispensable when the disk is fixed to the spindle motor.

However, in the small optical disk medium 1 of the present invention, as will be described later, the turntable 3 structure of the spindle motor 2 allows the small optical disk medium 1 to be centered without a center hole. Further, by eliminating the center hole, the data recording layer 7 can be greatly expanded to the disc center portion 1b, and as a result, the recording capacity can be increased.
That is, FIG. 10A shows a general small optical disc medium 101 having a center hole such as a CD or DVD, and the center hole 102 is opened at the center of the disc. The diameter on the inner circumference side of the data recording area 107 formed from the outer circumference portion 103 to the inner circumference portion of the disc cannot be reduced, and there is a limit to the expansion of the recording capacity.

However, in the small optical disk medium 1 of the present invention, as shown in FIG. 10B, since the center hole is not opened at the center of the disk, the data recording layer 7 has a diameter from the disk outer peripheral part 1a to the disk central part 1b. The recording capacity can be greatly increased up to about 0.5 mm toward the center of the disk, and the recording capacity can be greatly increased.
Further, in the conventional optical disk apparatus, generally, the data recording surface of the small optical disk medium 1 rotated by the turntable 3 faces downward, and data is read from the lower side of the small optical disk medium 1 by an optical pickup. For this reason, if the inner diameter of the data recording area 102 is to be reduced, the optical pickup will interfere with the spindle motor, and there is a limit to the expansion of the recording capacity.

However, in the optical disk apparatus of the present invention, as described with reference to FIG. 12, the spindle motor 2 and the optical pickup 4 are arranged on opposite sides of the small optical disk medium 1 so that the optical pickup 4 is accessed to the inner periphery of the disk. Even so, the optical pickup 4 and the spindle motor 2 do not interfere with each other. Accordingly, the data recording layer 7 is also formed by the absence of the center hole of the small optical disk medium 1 and the fact that the optical pickup 4 can be accessed to the center 1b of the small optical disk medium 1 without causing any interference with the spindle motor 2. The recording capacity can be increased by enlarging.
FIG. 11A shows a general small-sized optical disk medium 101 having a center hole such as a CD or a DVD. A picture or character formed by drawing or printing a picture or character. The layer 106 is greatly limited by the center hole 102 opened in the center of the disk, and the entire area occupied by the disk including the center hole 102 portion can be effectively used to display pictures, characters, etc. in a large and effective manner. Can not.

  However, since the small optical disk medium 1 of the present invention does not have a center hole as shown in FIG. 11B, the picture / character layer 6 is provided within the entire occupied area including the central portion 1b of the small optical disk medium 1. It can be formed over a wide range. Therefore, the display of pictures, characters, etc. is not limited by the center hall, and the pictures, letters, etc. can be displayed large and effectively, and the aesthetics and product value of the optical disk medium can be greatly improved. Can do.

Next, the optimum turntable 3 for the small optical disk medium of the present invention will be described with reference to FIGS.
The turntable 3 is integrally formed with a magnet (bonded magnet, sintered magnet or the like), and has a magnetic force MF in which the N pole and the S pole are magnetized in the vertical direction. Another feature is that the outer diameter of the turntable 3 is larger than the outer diameter of the small optical disk medium 1, and a cylindrical rib 10 for centering the small optical disk medium 1 on the outer periphery of the disk mounting surface 3a. Are integrally formed concentrically. As shown in FIG. 12, the small optical disk medium 1 is positioned so that the outer diameter thereof matches the inner diameter of the rib 10, and is attracted to the disk mounting surface 3a by the magnetic force MF. The outer diameter of the small optical disk medium 1 and the inner diameter of the rib 10 are designed with a gap of about 100 μm in consideration of each component tolerance.

  Even with this centering method, centering accuracy within ± 100 μm can be obtained, and centering can be performed with the same accuracy as the centering method using the conventional center hole. The rib 10 also serves as a stopper for preventing the small optical disk medium 1 from protruding in the circumferential direction during rotation. By this method, even the small optical disc medium 1 without the center hole can be centered with high accuracy on the turntable 3 with the same accuracy as the conventional one.

  Further, the turntable 3 has chamfers 11 at the corners between the inner peripheral surface 10a and the upper surface 10b of the rib 10, and the small optical disk medium 1 is inserted inside the rib 10 and placed on the disk mounting surface 3a. When attracting (attaching), the outer periphery of the small optical disk medium 1 can be guided by the chamfer 11 and smoothly guided to the inside of the rib 10. Therefore, the small optical disk medium 1 can be smoothly mounted on the disk mounting surface 3a of the turntable 3.

  The height of the rib 10 is equal to or less than the thickness of the small optical disk medium 1. When the small optical disk medium 1 is attached to or detached from the turntable 3, the optical pickup 4 moves further outward than the outermost periphery of the disk in order to improve operability. At this time, if the height of the rib 10 is higher than the disc thickness, a portion close to the small optical disc medium 1 such as the objective lens 4a of the optical pickup 4 may be caught by the rib 10 when moving in the radial direction of the turntable 3. Because there is. If the height of the rib 10 is lower than the thickness of the small optical disk medium 1, there is no possibility of being caught.

  Further, one or a plurality of notches 14 are formed on the outer peripheral portion of the turntable 3. This is a portion where a finger for gripping the small optical disk medium 1 enters when the small optical disk medium 1 is attached to or detached from the turntable 3. Without this notch 14, the rib 10 of the turntable 3 gets in the way, which is particularly difficult when removing the small optical disc medium 1.

  As described above, the small optical disk medium 1 has a wide surface from the inner periphery to the outer periphery, and has a method of being attracted to the turntable 3 by the magnetic force MF. In this method, even if the small optical disk medium 1 is warped, it is forcibly copied to the highly rigid disk mounting surface 3a side by the attractive force of the magnetic force MF. This means that if the flatness of the disc mounting surface 3a is improved, the flatness of the small optical disk medium 1 with a large warp can be corrected to a good flatness when actually used. Therefore, the warp of the small optical disk medium 1 is reduced in actual use by improving the flatness of the disk mounting surface 3a rather than the specifications of the surface runout and flatness determined by the standard of the small optical disk medium 1. effective. In other words, it is possible to relax the standard related to the warp of the small optical disk medium 1.

Furthermore, as shown in FIGS. 13 to 15, the turntable 3 can be formed with an annular recess 12 that is a relief in the height direction on the outer peripheral portion of the disk mounting surface 3 a. This dent 12 is a dent 12 for escaping when a portion where the thickness of the disc becomes thicker by about 50 μm or less is formed within a range of 1 to 2 mm from the outer peripheral edge of the small optical disc medium 1.
That is, as described with reference to FIG. 4, the small optical disc medium 1 has the protective film 9 formed by spin coating. In the spin coating method, a film is formed by using centrifugal force. However, only the outermost peripheral portion of the small optical disk medium 1 inevitably accumulates a transparent UV resin material or the like due to the surface tension, and the raised portion 15 becomes thicker. Is formed. Without the escape recess 12, when the small optical disk medium 1 is attracted to the disk mounting surface 3 a of the turntable 3, the raised portion 15 rides on the disk mounting surface 3 a (interference occurs). ) There is a possibility that the warp of the small-sized optical disc medium 1 will become larger.

  However, as described with reference to FIG. 5, the small optical disk medium 1 of the present invention simultaneously presses the six small optical disk medium processing regions 52 of the large metal substrate so that the six small optical disk media are removed from the large metal substrate. At the same time, the small optical disk medium is cut with a diameter D4 (= 30 mm) sufficiently smaller than the diameter D3 (= 53 mm) of the small optical disk medium processing region 52.

In other words, the small optical disk medium 1 is cut from the small optical disk medium processing area 52 by pressing so as to avoid the raised portion 15 of the protective film 9 generated in the outermost peripheral portion of the small optical disk medium processing area 52. The raised portion 15 of the protective film 9 as shown in FIG. 15 does not occur (exists) at the outermost peripheral portion of the small optical disc medium 1 manufactured according to the present invention.
Therefore, in the turntable 3 in which the small optical disk medium 1 of the present invention is used, the small optical disk medium 1 is loaded on the disk without forming an annular recess (relief) 12 on the outer peripheral portion of the disk mounting surface 3a. There exists the characteristic which can be made to contact | adhere with high precision in parallel on the mounting surface 3a.

Modified example

  As described above, the large metal substrate 50 does not necessarily have a disk shape, and may be a polygon as shown in FIGS. 16A and 16B, for example. Also, the plurality of small optical disk medium processing regions 52 arranged in the large metal substrate 50 do not necessarily need to be arranged in an equally spaced ring shape, and as shown in FIGS. A uniform arrangement may be used.

The present invention is not limited to the above-described embodiments, and various effective modifications can be made based on the technical idea of the present invention.
The optical disk medium of the present invention is not limited to an optical disk that records and / or reproduces data by an optical system, but can also be applied to a magneto-optical disk that records and / or reproduces data by a magneto-optical system.
Further, according to the optical disk medium of the present invention, the presence or absence of the center hole is not questioned. However, for example, the center hole of the optical disk medium can be simultaneously pressed during the pressing shown in FIG.
Further, in the above-described embodiments, the method for producing a small optical disk medium having a diameter of 30 cm is described as the optical disk medium of the present invention. However, the present invention is a large disk having a diameter of 12 cm or more such as a general CD or DVD. The present invention can also be applied to an optical disk medium manufacturing method.

It is a top view of the large sized (large diameter) metal substrate explaining the manufacturing method of the optical disk medium of this invention. It is sectional drawing explaining the manufacturing process of the data recording layer in the manufacturing method of the optical disk medium of this invention. It is sectional drawing explaining the process of a reflecting film in the manufacturing method of the optical disk medium of this invention. It is sectional drawing explaining the manufacturing process of the protective film in the manufacturing method of the optical disk medium of this invention. It is sectional drawing explaining the cutting process of the optical disk medium in the manufacturing method of the optical disk medium of this invention. It is the top view and side view which showed the whole optical disk medium manufactured by the manufacturing method of this invention. It is sectional drawing which expanded and showed the principal part at the time of applying the optical disk medium same as the above to a single-sided disk. It is sectional drawing which expanded and showed the principal part at the time of applying an optical disk medium same as the above to a double-sided disk. It is an expanded sectional view of the principal part explaining that the thickness of the data recording layer of an optical disk medium same as the above is enlarged, and the unnecessary reflected light by a picture and a character layer does not enter into required reflected light. It is a top view explaining the difference in recording capacity of the optical disk medium same as the above and a general optical disk having a center hole. It is a top view explaining the difference in display areas, such as a picture and a character, of the optical disk medium same as the above and the general optical disk which has a center hole. It is the partially cutaway side view which showed the principal part of the optical disk apparatus which reproduces | regenerates the optical disk medium same as the above. It is a top view explaining the turntable of an optical disk device same as the above. It is sectional drawing in the AA arrow of FIG. It is an expanded sectional view of the principal part explaining the bulging part of the outer peripheral part of a general optical disc medium, and the dent for escape of the turntable with respect to the bulging part. It is a top view explaining the modification of the large sized metal substrate of this invention.

Explanation of symbols

1 Optical disk medium (small optical disk medium)
5 Metal substrate 50 Large metal substrate 51 Center hole of large metal substrate 52 Small optical disk medium processing region of large metal substrate 53 Positioning hole of large metal substrate 54 Hole for balancing large metal substrate 6 Picture / character layer 7 Data recording layer 8 Reflective film 9 Protective film 60 Injection molding machine 61, 62 Mold of injection molding machine 63 Cavity of injection molding machine 64 Center pin of injection molding machine 65 Positioning pin of injection molding machine

Claims (11)

In the method of manufacturing an optical disk medium in which a data recording layer, a reflective film, and a protective film are laminated on at least one surface of a metal substrate,
A process of simultaneously processing a plurality of small optical disk media by laminating the data recording layer, the reflective film, and the protective film on each of a plurality of locations on at least one side of a single large metal substrate;
And a step of simultaneously pressing the plurality of small optical disk media from the large metal substrate. In a method of manufacturing an optical disk medium in which a picture / character layer, a data recording layer, a reflective film, and a protective film in which a picture, characters, etc. are drawn / printed on at least one surface of a metal substrate,
A process of simultaneously processing a plurality of small optical disc media by laminating the picture / character layer, the data recording layer, the reflective film, and the protective film on each of a plurality of locations on at least one side of a single large metal substrate;
And a step of simultaneously pressing the plurality of small optical disk media from the large metal substrate. 3. The method of manufacturing an optical disk medium according to claim 1, wherein the large metal substrate is controlled to rotate around a central hole in a horizontal plane. When the large metal substrate is rotationally controlled around the center hole in a horizontal plane, positioning in the rotational direction is performed by a positioning hole formed by a hole or a notch formed in the vicinity of the outer periphery of the large metal substrate. The method of manufacturing an optical disk medium according to claim 3, wherein the optical disk medium is configured as follows. When the large metal substrate is controlled to rotate around the central hole in a horizontal plane, the large metal substrate is formed of a hole or a notch formed at a position near the outer periphery of the large diameter metal substrate and substantially opposite to the positioning hole. 5. The method of manufacturing an optical disk medium according to claim 4, wherein the large metal substrate is rotationally balanced by a balancing hole comprising one or a plurality of holes or notches. 6. The optical disk medium according to claim 3, wherein the protective film is formed by a spin coating method while rotating the large metal substrate around the center hole in a horizontal plane. Method. A plurality of small optical disk medium processing regions in which the data recording layer, the reflective film, and the protective film formed by the spin coating method are laminated at the same time at a plurality of locations on at least one side of the single large metal substrate. The optical disk medium manufacturing method according to claim 6, wherein the optical disk medium is arranged in a ring shape around a rotation center of the large metal substrate. A plurality of small-size layers in which the picture / character layer, the data recording layer, the reflective film, and the protective film formed by the spin coating method are laminated simultaneously at a plurality of locations on at least one side of the single large metal substrate. The optical disk medium processing region is arranged in a ring shape around the rotation center of the large metal substrate,
The method of manufacturing an optical disk medium according to claim 6. 9. The method of manufacturing an optical disk medium according to claim 7, wherein a plurality of the small optical disk media are simultaneously manufactured by simultaneously pressing a plurality of the small optical disk medium processing regions. The large metal substrate has a diameter of approximately 120 mm or less,
10. The method of manufacturing an optical disk medium according to claim 9, wherein the plurality of small optical disk medium processing regions are formed to have a diameter of approximately 53 mm or less. When manufacturing the plurality of small optical disk media by simultaneously pressing the inside of the plurality of small optical disk medium processing regions, press the regions that are displaced by 2 mm or more inward from the outermost peripheral position of the small optical disk medium processing regions. The method of manufacturing an optical disk medium according to claim 10, wherein the optical disk medium is processed.

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