JP2007226888A - Molding die for disk substrate, disk substrate and optical disk product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding die for a disk substrate, for solving the problem that a flat label surface can not be widely secured on the surface opposite to a stack rib and a manufactured optical disk product has a bad appearance. <P>SOLUTION: In the molding die for the disk substrate 11 molding a disk substrate D1 in a cavity 14 formed between first and second metal molds 12 and 13, a stamper 16 forming a signal surface D2 and an annular recessed part 24 forming the stack rib D3 on the inner peripheral side of a part to which the stamper 16 is attached are provided in the first mold 12 and flat label surface forming surfaces 25a, 26a and 27a are formed on a part opposed to the stamper 16 and the annular recessed part 24 in the second mold 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disk substrate molding die, a disk substrate, and an optical disk product, and in particular, when a disk substrate that has been injection molded is held in an overlapping manner, the signal surface of the disk substrate is in contact with another disk substrate. The present invention relates to the formation of stack ribs that are not to be performed.

  Conventionally, as a disk substrate on which a stack rib is formed and a manufacturing method thereof, those disclosed in Patent Documents 1 to 3 are known. Patent Document 1 discloses a disk substrate having stack ribs formed on both sides. However, Patent Document 1 has a problem that since there are stack ribs on both sides, a flat label surface cannot be secured widely on one side, and printing or the like cannot be performed over a wide range, so that an optical disk product manufactured has a poor appearance. It was.

  Patent Document 2 discloses a disk substrate in which a stack rib is formed on the back side of a claw portion of a stamper holder. However, with respect to Patent Document 2, since a concave portion that is a mark of the stamper holder is formed on the opposite surface of the stack rib, the appearance of an optical disk product manufactured without being able to ensure a wide flat label surface on the opposite surface. There was a problem of being bad.

  Further, in Patent Document 3, an example close to Patent Document 1 is disclosed in FIG. 5, and the most general example is disclosed in FIG. And also about patent document 3, the position of the radial direction of a stack rib is provided in the same position as the recessed part formed of the nail | claw part of a stamper holder. However, the cited document 3 changes the width of the stack rib according to the circumferential direction to provide a thick portion and a thin portion, so that a recess that is a mark of the stamper holder is fitted to the stack rib, or two disk substrates are mounted. An example that can be overlapped with an interval is disclosed. However, also in Patent Document 3, since a concave portion formed by a stamper holder claw portion is provided on the opposite surface of the stack rib, a flat label surface cannot be secured widely on the opposite surface of the manufactured optical disc product. There was a problem that it looked bad.

JP 2006-12331 A (Claim 1, FIG. 1, FIG. 3, FIG. 4) JP 2000-207790 (0054, FIG. 10) JP 2002-251784 (Claim 1, FIG. 3, FIG. 5, FIG. 8, FIG. 9, FIG. 10)

In view of the above problems, the present invention provides a molding die for a disc substrate that solves the problem of poor appearance of an optical disc product that cannot be secured with a wide flat label surface on the opposite surface of the stack rib. The purpose is to do. It is another object of the present invention to provide a disk substrate and an optical disk product that solve the above problems. It is another object of the present invention to solve various problems in molding the disk substrate or manufacturing the optical disk product. The subject of the present invention is not limited to a specific disc substrate or a specific optical disc product, but in particular, a Blu-ray disc in which the laser beam used for reading is a short wavelength blue-violet laser beam or blue laser beam. It is suitably used for (Blu-ray Disk).

The disk substrate molding die according to claim 1 of the present invention is a disk substrate molding die for molding a disk substrate in a cavity formed between a first mold and a second mold. The first mold is provided with a stamper that forms a signal surface, and an annular recess that forms a stack rib on the inner peripheral side of a portion to which the stamper is attached, and the second mold is opposed to the stamper and the annular recess. A flat label surface forming surface is formed on the portion to be formed.

According to a second aspect of the present invention, there is provided a molding die for a disk substrate according to the first aspect, wherein the first die is a movable die, and the male cutter that forms the center hole of the disk substrate is disposed so as to be movable forward. An annular recess is provided between the claw portions of the inner peripheral stamper holder that holds the male cutter and the stamper.

The disk substrate according to claim 3 of the present invention is a disk substrate in which a signal surface is formed on one surface and a label surface is formed on the other surface. A stack rib protruding from the signal surface is formed on the inner peripheral side, and a flat label surface is formed on the other surface at a portion facing the signal surface and the stack rib.

The optical disc product according to claim 4 of the present invention is an optical disc product in which a protective layer for protecting a signal surface of a disc substrate is provided on one side and surface treatment is performed on the other side.
On one surface of the disk substrate, a signal surface and a stack rib protruding from the signal surface on the inner periphery side of the signal surface are formed, and a protective layer is provided on the signal surface excluding the stack rib portion. The other surface of the disc substrate is characterized in that a flat label surface is formed in a portion facing the signal surface and the stack rib, and the label surface is subjected to surface treatment.

The disk substrate molding die of the present invention is a disk substrate molding die for molding a disk substrate in a cavity formed between a first mold and a second mold. Is provided with a stamper that forms a signal surface, and an annular recess that forms a stack rib on the inner peripheral side of the portion to which the stamper is attached, and the second mold has a portion facing the stamper and the annular recess. Since a flat label surface forming surface is formed, the disk substrate to be molded must secure a wide label surface on the other surface facing one signal surface and on the portion facing the signal surface and the stack rib. Thus, it is possible to manufacture an optical disc product that does not interfere with the molding and cooling of the disc substrate and has a good appearance.

A molding die for a disk substrate according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of an essential part of a molding die for a disk substrate according to the present embodiment. The disk substrate molding die 11 of this embodiment is a disk substrate for Blu-ray Disc (compliant with Blu-ray Disc Rewritable Format) (registered trademark) having a plate thickness of 1.1 mm and a diameter of 120 mm (both including molding errors). It is for molding.

As shown in FIG. 1, a disk substrate molding die 11 includes a movable die 12 as a first die and a fixed die 13 as a second die. A cavity 14 having a variable volume is formed between the molds 12 and 13. A movable mold 12 attached to a movable platen of an injection molding machine (not shown) includes a movable mirror plate 15 fixed to a movable back plate (not shown), and a stamper disposed on the surface of the mirror plate 15 to form a signal surface. 16, an inner peripheral stamper holder 17 that is disposed in an inner peripheral hole of the mirror plate 15 and holds the stamper 16, a fixed sleeve 19 that is disposed in an inner peripheral hole of the inner peripheral stamper holder 17, and the fixed sleeve The ejector sleeve 20 disposed in the inner peripheral hole 19, the cylindrical male cutter 21 disposed in the inner peripheral hole of the ejector sleeve 20, the projecting pin 22 inserted into the inner peripheral hole of the male cutter 21, and the stamper The outer peripheral stamper holder etc. which hold | maintain the outer peripheral part of 16 is not shown.

Describing each part of the movable mold 12 as the first mold in detail, the mirror plate 15 is a thin cylindrical member, and the surface 15a on the cavity 14 side is mirror-finished. In addition, a cooling medium flow path 15b for flowing a cooling medium is formed on the back surface of the mirror plate 15 (the side fixed to the movable back plate). The inner peripheral stamper holder 17 is a cylindrical member, and a claw portion 18 for pressing the stamper 16 is provided at the outer peripheral end of the cavity forming surface. In the present embodiment, the outer peripheral end of the claw portion 18 is provided in a portion having a diameter of 22.3 mm. The claw 18 has a shape with a height of 0.1 mm to 0.4 mm, and a projecting dimension from the main body to the stamper 16 is about 0.1 mm to 0.2 mm. The stamper 16 has a plate thickness of about 0.2 mm to 0.6 mm, and has fine projections on the surface for forming signals on the signal surface D2 of the disk substrate D1. The signal surface D2 may be formed with a groove or the like in the case of a recordable disc.

The fixing sleeve 19 is a cylindrical member, and release air can be ejected from a gap 23 of about 20 μm with the inner peripheral stamper holder 17. The position of the gap 23 is preferably provided in the range of 17.0 mm to 20.5 mm in diameter. All the dimensions in these molds are the dimensions at room temperature. A part of an annular recess 24 for forming the stack rib D3 on the disk substrate D1 is formed on the cavity forming surface of the fixed sleeve 19. The ejector sleeve 20 is made of a cylindrical member, and is provided so as to be moved forward by a driving means (not shown) when the disk substrate D1 is released. A part of the annular recess 24 for forming the stack rib D3 is formed on the cavity forming surface of the ejector sleeve 20. Therefore, in this embodiment, the annular recess 24 is formed over both the fixed sleeve 19 and the ejector sleeve 20 provided between the claw portion 18 of the inner peripheral stamper holder 17 and the male cutter 21.

As described in the Background Art section, the purpose of providing the stack rib D3 on the disk substrate D1 is to prevent the disk substrates (particularly the signal surface) from contacting each other when the formed disk substrates D1 are stacked and cooled. It is to make it. In the present invention, the stack rib D3 is preferably provided with an outer peripheral end in a portion having a diameter of 16 mm to 22 mm, and more preferably provided in a portion having a diameter of 17 mm to 19.5 mm. The width of the rib base is preferably 0.5 mm to 5.0 mm, particularly preferably 0.8 mm to 2.0 mm, and the width of the rib top is preferably 0.1 mm to 2.0 mm. The height of the rib is preferably 0.1 mm to 0.3 mm. Accordingly, an annular recess 24 having a size corresponding to the stack rib D3 having the above-described shape is formed on the inner peripheral side of the portion to which the stamper 16 of the movable mold 12 is attached. The annular recess 24 may be provided with a plurality of recesses at an annular position and a plurality of stack ribs D3 arranged in an annular shape, even if the annular recess 24 is not completely continuous. In addition, the cross-sectional shape of the stack rib D3 is a trapezoidal shape in the present embodiment, but various forms are conceivable, such as one in which the upper surface side is an R surface and the top end is a corner.

As for the annular recess 24, any one of the inner peripheral stamper holder 17, the fixing sleeve 19, the ejector sleeve 20, or the like can be used as long as it is provided in a portion between the male cutter 21 and the claw portion 18 of the inner peripheral stamper holder 17. It may be provided over two or more. Furthermore, when the inner peripheral stamper holder and the fixing sleeve are inner peripheral stamper holders made of the same member, they may be provided on the surface of the inner peripheral stamper holder. In such a case, it is desirable to provide a release air ejection hole inside the annular recess or on the outer peripheral side of the annular recess. Furthermore, a part or all of the cavity forming surface of the annular recess 24 or the inner peripheral stamper holder 17 including the annular recess 24, the fixing sleeve 19, and the ejector sleeve 20 is roughened to Rz 0.05 μm to 0.4 μm. Release may be made easier.

On the other hand, a fixed mold 13 as a second mold attached to a fixed plate of an injection molding machine (not shown) includes a fixed mirror plate 25 fixed to a fixed back plate (not shown) and an inner peripheral hole of the mirror plate 25. A gate insert 26, a mescutter 27 disposed in an inner peripheral hole of the gate insert 26, a sprue bush 28 disposed in an inner peripheral hole of the mescutter 27, and the like. The mirror plate 25 is a thin cylindrical member, and the cavity forming surface 25a is mirror-finished. The cavity forming surface 25a may be roughened from Rz 0.05 μm to 0.4 μm to facilitate release, and the label surface D6 may be embossed. Further, a cooling medium flow path 25b for flowing a cooling medium is formed on the back surface (the side fixed to the fixed back plate) of the mirror plate 25. Air can be ejected from the gap 29 between the mirror plate 25 and the gate insert 26 at the time of mold release. A sprue bush 28 is disposed in the inner peripheral hole of the mescutter 27, and the front end surface of the sprue bush 28 is disposed so as to recede from the movable mold facing surface of the mescutter 27. The mescutter may be provided so that the inner peripheral hole side of the movable mold facing surface slightly protrudes as a countermeasure against burrs formed in the center hole D5 of the disk substrate D1.

The cavity forming surface 25a of the mirror plate 25 of the fixed mold 13, the cavity forming surface 26a of the gate insert 26, and the cavity forming surface 27a of the mescutter 27 are provided at the same height, and a label surface D6 is formed on the disk substrate D1. The label surface forming surface is configured. Accordingly, when the disk substrate D1 is molded, the label surface D6 where the surface opposite to the signal surface D2 of the disk substrate D1 is all flat (even if there is a slight burr due to the gap between the mold components) Are formed). Further, in the positional relationship between the movable mold 12 and the fixed mold 13, a fixed-side mirror plate 25 is disposed substantially opposite to the movable-side stamper 16. A gate insert 26 is disposed substantially opposite to the inner stamper holder 17 and the fixed sleeve 19. Further, a mescutter 27 is disposed substantially opposite to the ejector sleeve 20. Further, a sprue bush 28 is disposed substantially opposite to the male cutter 21, and the tip of the male cutter 21 provided so as to be able to move forward is fitted into the mescutter 27.

Next, a disk substrate D1 formed by the disk substrate molding die 11 of the present embodiment, and a Blu-ray Disc D (registered trademark) (hereinafter simply referred to as Blu-ray Disc D) which is an optical disk product manufactured using the disk substrate D1. ) And a method of manufacturing the Blu-ray Disc D will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view of the Blu-ray disc of this embodiment.

First, a procedure for forming the disk substrate D1 will be described. A mold clamping device of an injection molding machine (not shown) is operated to move the movable mold 12 attached to the movable platen, thereby closing the mold. As a result, the movable mold 12 is fitted to the fixed mold 13 attached to the fixed platen, and a cavity 14 having a variable volume is formed. Next, the screw of the injection device (not shown) is moved forward, and the molten resin in the heating cylinder of the injection device passes through the nozzle of the injection device and the sprue bush 28 of the fixed mold 13 in contact with the nozzle. 14 is injected and filled. In this embodiment, polycarbonate is used as the thermoplastic transparent resin, and it is injected and filled into the cavity 14 at a nozzle temperature of 300 ° C. to 340 ° C. Then, when the molten resin is injected and filled into the cavity 14, the mold clamping device is restarted at the same time or slightly back and forth to advance the movable mold 12 toward the fixed mold 13, and the molten resin in the cavity 14 is moved forward. So that a good transfer can be performed. In this embodiment, since the disk substrate D1 for the Blu-ray Disc D is molded, the movable mold 12 is located at a position where the distance between the stamper 16 and the cavity forming surface 25a of the mirror plate 25 on the fixed side is close to 1.1 mm. Is to be stopped.

Next, the male cutter 21 of the movable mold 12 is advanced toward the mescutter 27 of the fixed mold 13 to perform gate cutting, thereby opening the center hole D5 of the disk substrate D1. In this embodiment, since the center hole D5 is opened by the male cutter 21 from the side of the movable mold 12 that forms the signal surface D2, the burr on the placement portion D10 of the center hole D5 on which the Blu-ray disc D is placed at the time of reading is formed. It doesn't matter.

The molten resin injected and filled into the cavity 14 is cooled and solidified by the cooled disk substrate molding die 11 in parallel with the compression and the gate cut. Then, when the molten resin is cooled and solidified in the cavity 14, the gap 29 between the mirror plate 25 of the fixed mold 13 and the gate insert 26, the inner peripheral stamper holder 17 of the movable mold 12, and the fixed sleeve 19 are next. The ejection of release air is started from the gap 23 or the like. The movable mold 12 is moved backward while the mold release air is exerted between the cavity forming surface of the mold and the disk substrate D1, and the mold is opened. At that time, since release air is ejected from the gap 23 closer to the outer periphery than the annular recess 24 of the movable mold 12, air is sent to both the signal surface D 2 and the stack rib D 3 of the disk substrate D 1 with respect to the movable mold 12. Can be easily released. In the present embodiment, the molded disk substrate D1 and the sprue (not shown) are moved together with the movable mold 12 when the mold is opened, and the label surface D6 is adsorbed by a take-out robot which is a take-out machine (not shown) at the mold opening completion position. At the same time, the ejector sleeve 20 is completely released from the movable mold 12, and at the same time, the sprue is completely separated from the disk substrate D1 by the protruding pins 22.

The disc substrate D1 formed by the present embodiment constitutes the Blu-ray disc D shown in FIG. That is, the disk substrate D1 has a thickness of 1.1 mm, a diameter of 120 mm, and the center hole D5 has a diameter of 15 mm (all including a range of allowable molding errors). An outer peripheral end of a concave portion D4 formed by the claw portion 18 of the inner peripheral stamper holder 17 is provided in a portion having a diameter of 22 mm to 23 mm on one surface of the disk substrate D1 (the surface that is lower when reading). A signal surface D2 is formed by the stamper 16 on the outer peripheral side. Further, the outer peripheral end of the stack rib D3 is formed concentrically with the concave portion D4 at a position of a diameter of 16 mm to 22 mm on the inner peripheral side of the concave portion D4. Further, on the other surface (the upper surface when reading) of the disk substrate D1, the portion facing the signal surface D2 and the stack rib D3 is all flat except for slight burrs between members. A simple label surface D6 is formed.

Next, the disk substrate D1 taken out by the take-out robot is stacked on a cooling stocker (not shown) and cooled. The cooling stocker is provided with a vertical support column in the center, and the disk substrate D1 is placed so that the signal surface D2 serving as the lower surface is horizontal, with the center hole D5 being inserted through the support column. At this time, the disc substrate D1 is provided with a stack rib D3, and the front end surface of the stack rib D3 is brought into contact with the label surface D6 of the lower disc substrate D1, so that the disc substrates D1, D1 adjacent to each other vertically The label surface D6 and the signal surface D2 can be stacked so as not to contact each other.

When the cooling of the disk substrate D1 (including the annealing step) is completed, the disk substrate D1 is then transferred to an aluminum vapor deposition apparatus, where signal surface processing is performed by aluminum vapor deposition, and an aluminum vapor deposition layer D7 is formed on the signal surface D2. It is formed. Note that the signal surface processing may be performed by other methods. The disk substrate D1 on which the aluminum vapor deposition layer D7 has been formed is then provided with a protective layer D8 that protects the signal surface D2 (including the aluminum vapor deposition layer D7). In this embodiment, the protective layer D8 has a plate thickness of 0.1 mm, a diameter (outer diameter) that is the same as that of the disk substrate D1, and a diameter (inner diameter) of the center opening is the outer periphery of the recess D4 of the disk substrate D1. A resin plate provided larger than the end is attached with an adhesive. Therefore, since the central opening of the protective layer D8 is excluded from the stack rib D3 portion of the disk substrate D1, the stack rib D3 does not get in the way of bonding. The stack rib D3 in the disk substrate D1 is set to 0.2 mm to 0.3 mm in height so that the disk substrates D1 and D1 can be stacked without contacting each other even after the protective layer D8 is formed. . In addition to the above, the protective layer D8 is formed by applying a liquid resin on the signal surface D2, rotating the disk substrate D1, and curing the liquid resin by photocuring or infrared irradiation to form the protective layer D8. You may do it. The standard thickness of the protective layer D8 is 0.1 mm, but a range of 0.05 mm to 0.2 mm is also assumed.

Printing is performed on the label surface D6 of the disk substrate D1 on which the protective layer D8 is formed. In the present embodiment, the disk substrate D1 is formed from a label surface D6 that is flat in the vicinity of the center hole D5 or up to the center hole D5, and the printing layer D9 is formed on the substantially entire surface including the signal surface D2 and the opposing surface of the stack rib D3. Since the surface treatment such as printing for forming the optical disk is performed, an optical disk product with good appearance can be manufactured. However, it is not necessary to print the entire label surface D6, and printing may be performed within an area ratio of 80 to 100%. Further, the surface treatment of the label surface D6 may be performed by another surface treatment method such as attaching a film or paper regardless of printing. The signal surface processing, protective layer formation, and label surface printing are generally performed in this order, but the order may be changed. The Blu-ray Disc D manufactured through the above process is read using a blue laser beam or a blue-violet laser beam having a short wavelength (405 nm) from the side of one protective layer. Note that the Blu-ray Disc D of this embodiment is packed and distributed as it is and distributed as a product, and only the Blu-ray Disc D is set in a reader and read. However, the Blu-ray Disc D is distributed and stored as a product in a storage case. It does not exclude what is set in the reading device for each case.

Next, a disk substrate molding die 31 according to another embodiment shown in FIG. 3 will be described. FIG. 3 is a cross-sectional view of a main part of a molding die for a disk substrate according to another embodiment. The disk substrate molding die 31 is provided with an annular recess 36 for forming the stack rib D3a across the inner peripheral stamper holder 33, the fixed sleeve 34, and the ejector sleeve 35 provided in the movable die 32 as the first die. It has been. Therefore, the cavity forming surface of the fixed sleeve 34 is at a position (recessed position) that is lower than the fixed mold facing surface on the outer peripheral side of the inner peripheral stamper holder 33 and the fixed mold facing surface on the inner peripheral side of the ejector sleeve 35. It will be. Release air is ejected from a gap 37 between the inner stamper holder 33 and the fixed sleeve 34. Further, in the present embodiment, the claw portion 38 of the inner peripheral stamper holder 33 is not projected to the fixed mold 42 side which is the second mold, and as the back surface of the claw portion 38 goes to the fixed mold 42 side. The taper shape is expanded. The center hole 40 of the stamper 39 that is locked to the claw portion 38 is enlarged in diameter toward the back surface side (movable side mirror surface plate 41 side). Therefore, in the present embodiment, the stamper 39 is held by the claw portion 38 of the inner peripheral stamper holder 33 that does not protrude from the surface of the stamper 39 and has a flat fixed mold facing surface. Therefore, when the molten resin is injected and filled into the cavity 43, the claw portion 38 does not hinder the flow of the molten resin, and the release air blown from the gap 37 is sent between the stamper 39 and the signal surface D2a of the disk substrate D1a. It is easy to affect.

The other members of the movable mold 32 and the fixed mold 42 in the molding die 31 of the disk substrate in FIG. 3 are the same as those in the embodiment shown in FIG. Since the procedure for molding the disc substrate D1a and the procedure for producing the Blu-ray Disc Da, which is an optical disc product produced from the disc substrate D1a, are also the same, description thereof is omitted. Then, the blu-ray disc Da produced by the molding die 31 of the flat disc substrate is formed by the claw portion 38 as shown in FIG. The feature is that the part is flat. Therefore, it is possible to provide the protective layer D8a closer to the stack rib D3a as necessary.

Next, a disk substrate molding die 51 of still another embodiment shown in FIG. 5 will be described. FIG. 5 is a sectional view of an essential part of a molding die for a disk substrate according to still another embodiment. In the disk substrate molding die 51, a stamper 54 for forming a signal surface is disposed on the surface of the fixed-side mirror plate 53 in the stationary die 52 which is the first die. In the fixed mold 52, an inner peripheral stamper holder 55 is disposed in the inner peripheral hole of the mirror plate 53, and the stamper 54 is held by a claw portion 56 of the inner peripheral stamper holder 55. Further, the fixed mold 52 is provided with a mescutter 57 in an inner peripheral hole of the inner peripheral stamper holder 55, and a sprue bush 58 is disposed in the mescutter 57 at a retracted position. An annular recess 59 for forming the stack rib D3 is formed on the cavity forming surface of the mescutter 57. Further, a gap 60 for ejecting release air is provided between the inner peripheral stamper holder 55 and the mesh cutter 57. The annular recess 59 may be provided only on the inner circumferential stamper holder 55 or over both the inner circumferential stamper holder 55 and the mescutter 57. The inner circumferential stamper holder 55 and the mescutter 57 are formed from the same member, and It may be provided. When the annular recess 59 is provided in the mescutter 57, release air from the gap 60 between the mescutter 57 and the inner peripheral stamper holder 55 is supplied to both the stamper 54 side and the annular recess 59 side, so that good release can be performed.

Further, the movable mold 61 which is the second mold of the embodiment shown in FIG. 5 is provided with a movable mirror plate 62 at a position facing the stamper 54, and the inner periphery of the mirror plate 62. A fixing sleeve 63 is disposed in the hole at a position facing the inner circumferential stamper holder 55. In addition, an ejector sleeve 64 is disposed in the inner peripheral hole of the fixed sleeve 63 at a position facing the mescutter 57. The cavity forming surface 62a of the mirror plate 62, the cavity forming surface 63a of the fixing sleeve 63, and the cavity forming surface 64a of the ejector sleeve 64 are provided at the same height, and a flat label surface D6 can be formed on the disk substrate D1. ing. The point that the cavity 65 having a variable volume is formed between the fixed mold 52 and the movable mold 61 is the same as the disk substrate molding mold 11 shown in FIG.

Therefore, the disk substrate D1 formed by the disk substrate molding die 51 is substantially the same as the disk substrate D1 shown in FIG. If the shape of the stamper holder and the shape of the center hole of the stamper are changed, a disk substrate D1a as shown in FIG. 4 can be formed. Further, the forming procedure of the disk substrate D1 and the manufacturing procedure of the optical disk product D manufactured from the disk substrate D1 are substantially the same, and thus the description thereof is omitted.

The present invention is not enumerated one by one, but is not limited to the one in the above-described embodiment, and it goes without saying that the present invention is applied to those modified by a person skilled in the art based on the gist of the present invention. It is. The kind of resin used is not limited to the above-mentioned polycarbonate, and other resins excellent in optical properties may be used. Further, the signal surface is not formed by a stamper of a molding die for the disk substrate, but may be formed by performing transfer using a photo-curing resin on the stamper surface in a subsequent process.

It is principal part sectional drawing of the shaping | molding die of the disc substrate of this embodiment. It is an expanded sectional view of the Blu-ray disc of this embodiment. It is principal part sectional drawing of the shaping | molding die of the disc substrate of another embodiment. It is an expanded sectional view of the Blu-ray disc of another embodiment. It is principal part sectional drawing of the shaping | molding die of the disc substrate of another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Disc substrate shaping die 12 Movable die 13 Fixed die 14 Cavity 15, 25 Mirror plate 15a Surface 15b, 25b Cooling medium flow path 16 Stamper 17 Inner peripheral stamper holder 18 Claw part 19 Fixed sleeve 20 Ejector sleeve 21 Oscutter 22 Projection pin 23, 29 Gap 24 Annular recess 25a, 26a, 27a Cavity forming surface 26 Gate insert 27 Mess cutter 28 Sprue bush D Blu-ray disc (optical disc product)
D1 Disc substrate D2 Signal surface D3 Stack rib D4 Concavity D5 Center hole D6 Label surface D7 Aluminum vapor deposition layer D8 Protective layer D9 Print layer D10 Place

Claims (4)

In a disk substrate molding die for molding a disk substrate in a cavity formed between a first mold and a second mold,
The first mold is provided with a stamper that forms a signal surface, and an annular recess that forms a stack rib on the inner peripheral side of a portion to which the stamper is attached,
2. A disk substrate molding die characterized in that a flat label surface forming surface is formed in a portion facing the stamper and the annular recess in the second die. The first mold is a movable mold;
The male cutter that forms the center hole of the disk substrate is arranged to be movable forward,
2. The disk substrate molding die according to claim 1, wherein the annular recess is provided between the claw portions of the inner peripheral stamper holder that holds the male cutter and the stamper. In the disk substrate in which the signal surface is formed on one surface and the label surface is formed on the other surface,
The one surface is formed with a signal surface and a stack rib protruding from the signal surface on the inner peripheral side of the signal surface,
2. A disk substrate according to claim 1, wherein a flat label surface is formed on a portion facing the signal surface and the stack rib on the other surface. In an optical disc product in which a protective layer for protecting the signal surface of the disc substrate is provided on one side and surface treatment is performed on the other side,
On one surface of the disk substrate, a signal surface and a stack rib projecting from the signal surface on the inner peripheral side of the signal surface are formed, and the signal surface is formed by excluding the stack rib portion. Is provided with a protective layer,
An optical disc product, characterized in that a flat label surface is formed on the other surface of the disc substrate at a portion facing the signal surface and the stack rib, and the label surface is subjected to a surface treatment.

Images