JP2007310995A - Optical disk and holder set for same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk which has a low price ranked with that of a CD or DVD and wherein recording/reproduction can be performed in a usual optical disk drive and to provide a holder set for the optical disk. <P>SOLUTION: In the optical disk provided with a flexible film disk 2 having an information recording layer 12 and a plate-shaped holder 3 on which the film disk is superposed, an adhesive layer 16 peelably sticking the film disk is formed on the surface of the holder at the position on which an information recording region 6 in the information recording layer of the film disk is superposed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc including a flexible film disc and a plate-like holder to which the film disc is bonded, and more particularly to an optical disc suitable for use in a Blu-ray disc as a next generation optical disc.

  In recent years, the capacity of optical discs has been increasing, and as a disc with higher density and larger capacity than DVD (Digital Versatile Disc), a Blu-ray Disc using a blue-violet light source (wavelength of about 405 nm) is used. : Hereinafter referred to as BD) has been commercialized. The BD forms a fine laser spot using a lens having a very thin transparent resin layer of about 0.1 mm from the disk surface to the recording reflective layer and a numerical aperture (NA) of about 0.85. Information is recorded or reproduced in the information recording. BD is a large-capacity medium of about 25 Gbytes for single-sided single-layer recording and about 50 Gbytes for single-sided dual-layer recording, about 5 times that of DVD.

  A method for manufacturing a BD will be described. First, an information recording layer is formed on a substrate having a thickness of 1.1 mm. Next, there is a method in which a 0.1 mm-thick cover layer is produced by laminating a transparent film or applying an ultraviolet curable resin on the information recording layer to obtain a BD having a total thickness of 1.2 mm. This method has a problem that the manufacturing process is complicated and there are many processes. Manufacturing processes such as bonding resin sheets or applying resin are complicated. Furthermore, since it has a multilayer structure, there are many manufacturing processes.

  In another method, first, an information recording layer is formed on a transparent film (0.07 to 0.09 mm thick) to a total thickness of 0.1 mm. Next, there is a method of manufacturing a BD having a total thickness of 1.2 mm by bonding this film and a thick substrate (1.1 mm thick).

  However, since the pits formed in the information recording pattern are extremely small with a length of 0.3 to 0.149 μm and a depth of 50 nm, transfer by the injection molding method is close to the limit, and the recording pattern from the disk surface Since the standard for the thickness is limited to 0.1 mm, the handling in the manufacturing process is difficult and loss is likely to occur.

  In addition, hard coating is essential because it easily affects scratches and dirt on the disk surface. Furthermore, the thickness unevenness from the disk surface to the recording layer is within ± 2 μm tolerance in the multi-layer process such as bonding and resin coating. Therefore, high-precision thickness control is required. The polycarbonate film used for the BD cover film is made by the solvent casting method (a method in which the raw material is dissolved in a solvent and spread into a film, and the solvent is removed to form a film). Although it is small, the productivity is poor and the required quality of the BD product is high, so the loss rate is high and the cost is high.

  In order to spread this BD, cost reduction is indispensable as well as CD and DVD. Therefore, a flexible optical disk having an information recording layer formed on a flexible film and having a thickness of about 0.1 mm has been studied.

  As a method for recording / reproducing the flexible optical disc, for example, a method using a stabilization guide based on Bernoulli's law has been proposed (Patent Document 1, Patent Document 2). This is a method in which an air layer with a certain thickness is generated by bringing the guide closer to the opposite side of the pickup of the flexible optical disk rotated at high speed, thereby correcting the warp, undulation and unevenness of the flexible optical disk.

However, the above method requires a stabilization guide and is not compatible with a general optical disc such as a BD. Furthermore, if the flexible optical disk is not always rotated at a high speed, Bernoulli's law will not be established, and the disk may be bent by its own weight when stopped or rotated at a low speed, and may come into contact with the pickup or the stabilizing guide. Although it is technically possible to retract the disk, the pickup, or the stabilization guide when the rotation of the disk is stopped or when the rotation is low, it causes a cost increase.
JP 2003-22651 A JP 2003-68050 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disc that can be recorded / reproduced with a normal optical disc drive at the same price as a CD or DVD, and a holder set for the optical disc.

In order to solve the above problems, the present invention comprises a flexible film disc having an information recording layer, and a plate-like holder on which the film disc is stacked. An adhesive layer for releasably bonding the film disk is formed at a position where the information recording area in the information recording layer is overlapped.
By adopting such a configuration and forming a disc in which the flexible film disc and the holder are bonded to various dimensions of the BD standard, the disc can be played on a BD standard player.

In this optical disc, a center hole may be formed at the center of the film disc and the holder, and the adhesive layer of the holder may be formed so as to avoid an annular region around the center hole.
That is, when aligning the holder and the film disc, the center hole peripheral portion of the film disc is overlapped with the peripheral portion of the center hole of the holder, and both center holes are aligned. Since there is no adhesive layer in the periphery of the hole, both can be aligned while sliding the film disc on the holder.

Further, an annular protrusion surrounding the center hole is formed in the periphery of the center hole of the holder, and an annular recess is formed in the film disc to fit the annular protrusion of the holder. Further, an annular wall portion for fitting the film disc is provided on the outer peripheral portion of the holder, and the film disc is sandwiched between the top of the annular wall portion and the surface of the adhesive layer. Protrusions are formed radially inward, or engaged on the outer peripheral surface of the holder and the outer peripheral surface of the film disc when the film disc is bonded to the adhesive layer of the holder. It is good also as a structure by which several protrusion and recessed part used as a state are arrange | positioned at intervals in the circumferential direction.
With these configurations, it is possible to reliably prevent the film disc adhered to the holder from being displaced.

Also, as such an optical disc holder set, a plate-like holder having an adhesive layer for releasably attaching a flexible film disc having an information recording layer, and a cleaner having an adhesive layer for releasably attaching the holder The cleaner plate has an adhesive layer having an adhesive force larger than that of the adhesive layer of the holder.
By adhering the adhesive layer of the holder to the adhesive layer of the cleaner plate and then peeling them off, dust and dirt adhering to the adhesive layer of the holder can be attached to the adhesive layer of the cleaner plate.

  According to the present invention, by mounting a flexible film disc having an information recording layer on a holder, it can be played back on a BD standard player. Since the holder of the optical disc can be used repeatedly, the consumer only needs to replace the film disc having the recording layer, and the price of Blu-ray Disc-ROM (hereinafter referred to as BD-ROM) can be greatly reduced. Furthermore, since the film disk having the recording layer is thin and lightweight, a large number of ROMs can be easily carried and the storage space can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The optical disc of this embodiment is designed to be handled as a disc conforming to the BD-ROM standard.

This optical disc 1 has a structure in which a flexible film disc 2 and a relatively rigid plate-like holder 3 are laminated and bonded together, and as shown in FIG. 1, a positioning center hole 4 is provided at the center. It is formed through the film disk 2 and the holder 3.
The optical disc 1 has, for example, an outer diameter of 120 mm and a center hole 4 having a diameter of 15 mm. As shown by a film disc 2 in FIG. 2, the position from the center hole 4 to the outer diameter of 33 mm is a clamp area 5, Further, the position from the 42 mm diameter to 117 mm is the information recording area 6, and the rim area 7 is from the outside to the 120 mm diameter.

In the film disk 2, an information recording layer 12 is formed on the surface of a flexible film substrate 11, a reflective layer 13 is formed on the information recording layer 12, and a protective layer 14 is formed thereon. The thickness is about 0.1 mm.
As the film substrate 11, a highly transparent material that transmits ultraviolet rays and a material having low birefringence are used, and examples thereof include polycarbonate, polymethyl methacrylate, and triacetyl cellulose.

The information recording layer 12 is formed by transferring pits from an original stamper to an ultraviolet (UV) curable acrylic resin layer and curing the ultraviolet rays.
The reflection layer 13 is formed by forming a thin film of aluminum, silver or an alloy thereof on the information recording layer 12 on which pits are formed by sputtering or vapor deposition.
The protective layer 14 is formed by sticking a protective film with adhesive on the surface of the reflective layer 13.

On the other hand, as shown in FIG. 1, the holder 3 is formed with a center hole 4 at the center of the base plate 15 and a thick ring-shaped portion 15a surrounding the periphery of the center hole 4. The adhesive layer 16 is formed on the surface of the thin portion around the portion 15a. The ring-shaped portion 15a and the adhesive layer 16 are flush with each other, for example, with a thickness of 1.1 mm as a whole. Is formed.
The material that can be used for the base plate 15 is not particularly limited as long as it is a smooth base material. For example, polycarbonate, polyethylene terephthalate, acrylic resin, paper, or the like can be used.

  Further, the adhesive layer 16 on the surface of the base plate 15 is formed in an area corresponding to the information recording area 6 and the rim area 7 other than the clamp area 5 in the film disk 2 when the film disk 2 is overlapped. Yes. This adhesive layer 16 is formed by applying a re-peelable weak pressure-sensitive adhesive, and this pressure-sensitive adhesive may be, for example, a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, or a silicone-based pressure-sensitive adhesive. However, among them, an acrylic pressure-sensitive adhesive is suitable because it is environmentally friendly and easily has an arbitrary adhesive property.

  Moreover, it is good also as resin which has adsorptivity as an alternative of the weakly removable adhesive. In the case of these adsorptive resins, there is little adhesive residue and excellent removability. As the adsorptive resin, for example, a fixed film (trade name) manufactured by Fuji Copian Co., Ltd. and a quintack (trade name) manufactured by Nippon Zeon, which is an elastomer having a block structure of polystyrene-polyisoprene, are suitable. In the present invention, this adhesion and adsorption are referred to as adhesion.

  The optical disk 1 configured as described above is handled only by the film disk 2 one by one or as a set of a plurality of films at the time of distribution or the like, and at the time of recording / reproducing, as shown by the arrows in FIG. Is attached to the adhesive layer 16 of the holder 3 for use. This bonded state is shown in FIG. 3, and in this state, the outer diameter is 120 mm, the diameter of the center hole 4 is 15 mm, and the total thickness is the same as that of a normal BD of 1.2 mm. Thus, recording and playback can be performed with a normal BD standard player.

  Further, during the bonding operation, the ring-shaped portion 15 a corresponding to the clamp area 5 of the holder 3 is not provided with the adhesive layer 16, so that the center hole 4 of the film disk 2 is replaced with the center hole 4 of the holder 3. Can be positioned while sliding the film disk 2 on the surface of the ring-shaped portion 15a, the alignment work becomes easy, and the two are integrated in an accurately positioned state. Can do.

  On the other hand, FIG. 4 shows the cleaner plate 21 of the holder 3, and this cleaner plate 21 has a configuration in which a peelable adhesive layer 23 formed by applying a strong adhesive to the surface of the base plate 22 is formed. is there. In this case, examples of the material used for the adhesive layer 23 of the cleaner 21 include adhesives such as rubber adhesives, acrylic adhesives, and silicone adhesives, and fixed films (trade names) manufactured by Fuji Copian Co., Ltd. Although an adsorbent such as ZEON Corporation Quinter (trade name) can be used, a material having an adhesive strength larger than the adhesive strength of the adhesive layer 16 of the holder 3 is used.

  Then, after adhering the adhesive layer 16 of the holder 3 to the adhesive layer 23 of the cleaner plate 21 and then removing them, if the holder 3 has dirt adhering or dirty, foreign matter such as dust or dirt will be removed. It is adhered to the adhesive layer 23 of the cleaner plate 21 and the surface of the adhesive layer 16 of the holder 3 is cleaned. Therefore, the holder 3 may be adhered to the cleaner plate 21 at the time of storage or the like and peeled off from the cleaner plate 21 when used as the optical disc 1. In particular, when the film disk 2 is inserted into the information recording area 6 and adhered to the holder 3, the surface of the film disk 2 is uneven at that portion, which hinders recording and reproduction, but the cleaner plate 21 Thus, the foreign matter on the surface of the holder 3 can be reliably removed.

  In this case, the adhesive layer 23 of the cleaner plate 21 has a laminated structure of a plurality of layers. When the adhesive force of the outermost adhesive layer is reduced by repeated use, the outermost adhesive layer is peeled off to form a new adhesive surface. It is good also as a structure which can do.

  FIG. 5 shows a second embodiment of the present invention. In this optical disc 31, an annular portion protruding from the ring-shaped portion 15a of the first embodiment is formed at the clamp area (see FIG. 2) of the holder 32. Providing the protrusion 33 and, on the other hand, providing the annular recess 35 for fitting the annular protrusion 33 on the film disk 34 side is effective as a measure for preventing the positional deviation between the two and the alignment.

  Further, as in the third embodiment shown in FIG. 6, an annular wall 43 is provided along the circumferential direction on the outer periphery of the holder 42 of the optical disc 41, and the top of the annular wall 43 is formed to be slightly wider. Thus, a projection 44 directed radially inward may be formed, and the film disk 45 bonded to the adhesive layer 16 may be sandwiched between the projection 44 and the adhesive layer 16. Further, as shown in the third embodiment of FIG. 7, a plurality of protrusions 53 are provided in the rim area (see FIG. 2) of the holder 52 of the optical disk 51 at intervals in the circumferential direction, and the protrusions 53 are engaged with the film disk 54. It is good also as a structure which provided the recessed part 55 to perform. By adopting these configurations, it is effective as a measure for aligning the holder 52 and the film disk 54 and preventing misalignment. These holders can be molded by injection molding or UV molding using an ultraviolet curable resin.

Next, an example in which the optical disk of the present invention is applied to a BD-ROM will be described.
A polycarbonate having a thickness of 90 μm is used as the film base 11 of the film disk 2, and a 500 cps acrylic ultraviolet curable resin is applied on the surface thereof to a thickness of about 10 μm.
The type of the film substrate 11 is preferably a material that has good adhesion to the resin, low birefringence, and transmits ultraviolet rays. For example, acrylic (PMMA), triacetyl cellulose (TAC), and the like are suitable.

  The type of UV curable resin is a resin that undergoes a radical polymerization reaction, and is an acrylic resin having an acryloyl group in the molecule. Epoxy acrylate, urethane acrylate, polyester acrylate, polyol acrylate oligomers, polymers and monofunctional Bifunctional or polyfunctional polymerizable (meth) acrylic monomers such as tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate , Pentaerythritol triacrylate, pentaerythritol tetraacrylate and other monomers, oligomers and polymers You can use. The thickness is preferably 5 to 50 μm and the viscosity is preferably about 300 to 5000 cps.

  Next, using a stamper wound around the cylinder (both not shown), the ultraviolet curable resin layer and the cylinder stamper surface are pressure-bonded and cured by irradiating with ultraviolet rays on a flat surface, and then peeled while being held by a peeling roll. Thus, the information recording layer 12 having pits transferred to one surface of the film base 11 is formed. In addition, since a drive roll has a cooling effect, it is good to set it as the structure which lets cooling water pass.

Next, a smooth nickel foil having a thickness of 30 μm subjected to adhesive processing is bonded to the information recording layer 12 as the reflective layer 13. The reflective layer foil may be any material having an appropriate reflectance with respect to the recording / reproducing laser wavelength, but the surface smoothness (Ra) is required to be 3 nm or less, and preferably 1 nm or less.
In this case, like a general optical disk, a reflection film is formed on the pits by sputtering or vapor deposition, and the signal is read by the reflected light cancellation effect using the optical path length difference depending on the presence or absence of the pits, or nickel. Either a pit-like space portion that can be obtained by laminating a foil on the information recording layer and a method of reading a signal by a difference in optical optical path length generated by a difference in refractive index between the resin portion can be adopted. . In the latter case, the work is performed in an atmosphere of an inert gas such as nitrogen or argon, whereby the pit is filled with the inert gas, and a more reliable disk can be manufactured. When applied to BD, the pit depth is preferably 50 to 150 nm in consideration of the laser wavelength of 405 mm, the resin refractive index of about 1.5, and the air refractive index of about 1.0.

  Further, a polycarbonate film having a thickness of 50 μm was bonded as the protective layer 14, the thickness of the entire disk was set to 180 μm, and the film was punched into an outer diameter of 119 mm and an inner diameter of 30 mm to obtain a film disk 2. When applied to BD, an outer diameter of 118 to 120 mm and an inner diameter of 20 to 40 mm are preferable.

  On the other hand, the holder 3 is formed by applying an adhesive made of an acrylic emulsion around the ring-shaped portion 15a of the base plate 15 made of polycarbonate or polyethylene terephthalate, acrylic resin, paper or the like having an outer diameter of 120 mm and a center hole diameter of 15 mm. The total thickness of the adhesive layer 16 was 1.02 mm. By mounting the film disc 2 on the holder 3, the dimensions satisfy the BD standard value, and recording / reproduction with a general BD drive becomes possible.

It is a half section perspective view of the state where the optical disk in one embodiment of the present invention was disassembled. FIG. 2 is a plan view of the film disc of FIG. FIG. 2 is a half cross-sectional perspective view in which the optical disk of FIG. 1 is bonded. FIG. 2 is a half sectional perspective view showing a holder and a cleaner in the optical disc of FIG. 1. FIG. 5 is a half sectional perspective view showing an optical disc in a second embodiment of the present invention. FIG. 5 is a half sectional perspective view showing an optical disc in a third embodiment of the present invention. It is a semi-sectional perspective view which shows the optical disk in 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 .... Film disc 3 .... Holder 4 .... Center hole 5 ... Clamp area 6 ... Information recording area 7 ... Rim area 11 ... Film base material 12 ... Information recording layer 13 ... Reflective layer 14 ... Protective layer 15 ... Base Material plate 15a ... Ring-shaped portion 16 ... Adhesive layer 21 ... Cleaner plate 22 ... Base plate 23 ... Adhesive layer 31 ... Optical disc 32 ... Holder 33 ... Circular projection 34 ... Film disc 35 ... Annular recess 41 ... Optical disc 42 ... Holder 43 ... Annular wall 44 ... Projection 45 ... Film disc 51 ... Optical disc 52 ... Holder 53 ... Projection 54 ... Film disc 55 ... Recess

Claims (6)

  A flexible film disc having an information recording layer and a plate-like holder on which the film disc is stacked, and on the surface of the holder, an information recording area in the information recording layer of the film disc is stacked. An optical disk, wherein an adhesive layer for releasably bonding the film disk is formed.   2. The optical disk according to claim 1, wherein a center hole is formed in the center of the film disk and the holder, and an adhesive layer of the holder is formed so as to avoid an annular region around the center hole.   An annular protrusion surrounding the center hole is formed on the periphery of the center hole of the holder, and an annular recess for fitting the annular protrusion of the holder is formed on the film disc. The optical disk according to claim 2.   An annular wall portion that fits the film disc is erected on the outer peripheral portion of the holder, and a projection that sandwiches the film disc between the surface of the adhesive layer and the top surface of the annular wall portion is radially inward. 4. The optical disk according to claim 1, wherein the optical disk is formed toward the head.   On the outer peripheral surface of the holder and the outer peripheral surface of the film disc, a plurality of protrusions and concave portions that are engaged when the film disc is bonded to the adhesive layer of the holder are arranged at intervals in the circumferential direction. 5. The optical disc according to claim 1, wherein the optical disc is provided. A plate-like holder having an adhesive layer for releasably attaching a flexible film disc having an information recording layer, and a cleaner plate having an adhesive layer for releasably attaching the holder, and an adhesive layer for the cleaner plate Is a holder set for an optical disc characterized by having an adhesive force larger than the adhesive force in the adhesive layer of the holder.

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