JP2007310994A - Flexible optical disk and holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible optical disk, to which recording and reproduction is possible with a normal optical disk drive by being mounted on a holder and which can be mounted and removed easily and repeatedly, and decrease the errors in recording and reproduction due to the adhesion of dust, scratches, dirt or the like. <P>SOLUTION: The flexible optical disk, which allows recording and reproducing information thereto/therefrom, is provided with a reflecting layer 5, which comprises a flat ferromagnetic body foil, on a protective film 6 side from a recording layer 11, and a holder for mounting the flexible optical disk is provided with a magnet in its inner part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flexible optical disc (hereinafter referred to as a flexible optical disc) capable of recording / reproducing information, and a holder thereof.

   As a substrate for a general optical disk, a resin such as polycarbonate, acrylic, polyolefin, etc. having a thickness of about 1.2 mm, glass or the like is used. However, a flexible optical disk manufactured by a roll-to-roll method using a flexible film having a thickness of about 30 to 300 μm for a substrate has been studied in order to improve productivity and reduce materials.

   As a method of forming information pits and pregrooves (hereinafter referred to as pits) on the film, ultraviolet curable resin is applied to the film surface, and ultraviolet rays are irradiated while pressing a master having pits (hereinafter referred to as stampers). There are a method and a method in which a thermoplastic resin is applied to the film or a thermoplastic resin is used for the film itself, and the stamper and / or the film is pressed while being heated.

   If the pit-formed film is a write-once or rewritable disc, a recording dye is applied or a recording film is formed by sputtering or vapor deposition. If necessary, a reflective film such as an aluminum alloy or a silver alloy is sputtered. Or it forms by vapor deposition and laminates | stacks a protective film and a protective film further. In the case of a read-only disc, the steps of applying a recording dye, sputtering the recording layer, and vapor deposition can be omitted. Thereafter, the inner and outer diameters are punched out to a predetermined size to complete the flexible optical disk.

As a method for recording / reproducing a completed flexible optical disc, for example, a method using a stabilization guide based on Bernoulli's law has been proposed (see, for example, Patent Document 1 and Patent Document 2).
In the method proposed in Patent Document 1 or Patent Document 2, a stabilization guide is provided on the opposite side of the optical pickup device with respect to a flexible optical disk rotating at high speed, and the stabilization guide is brought close to the flexible optical disk to In this method, a difference in air pressure is generated based on Bernoulli's law before and after the pick-up point, thereby correcting the warp, undulation and unevenness of the flexible optical disk.
JP 2003-22651 A JP 2003-68050 A

   However, the above method requires a stabilization guide and is not compatible with an optical disc recorded or reproduced by a general optical disc device such as a Blu-ray disc (BD) as a recording / reproducing device. Furthermore, Bernoulli's law does not hold unless the flexible optical disk is rotated at a high speed at all times, and the flexible optical disk may be bent by its own weight when the flexible optical disk rotates at a low speed, such as when stopped or started, and may come into contact with the pickup or the stabilization guide. Although it is technically possible to make the apparatus have a structure in which the flexible optical disk, the pickup, or the stabilization guide is retracted when the rotation of the flexible optical disk is stopped or when the rotation is low, it causes a cost increase.

As another method, a method of reading in a state where the flexible optical disk is supported by a holder and storing it in an apparatus for writing can be considered.
In order to fix the flexible optical disk to the holder, an adhesive layer or a mechanical claw is provided on the holder, and the flexible optical disk is mounted so as to have the same dimensions as a general optical disk.

However, when an adhesive is used, dust tends to adhere to the adhesive, which causes unevenness of the disk surface. In addition, since the holder and the flexible optical disk are brought into close contact with each other, it is necessary to press the disk against the holder by any method, which is likely to cause scratches and dirt on the signal surface.
In addition, it is difficult to correct the undulation and warpage of the flexible optical disk with mechanical claws, and deformation due to repeated attachment and detachment also occurs.

   The present invention has been made in view of the above circumstances, and can be recorded or reproduced by a normal optical disk drive by being mounted on a holder, and can be easily attached to and removed from the holder repeatedly. An object of the present invention is to provide a flexible optical disk with less errors during recording or reproduction due to adhesion, scratches, dirt, etc.

In order to solve the above problems, the present invention provides the following means.
A flexible optical disc according to the present invention is a flexible optical disc that is flexible and used by being stacked on a disc-shaped holder, and includes a recording layer formed on one surface of a film substrate, and the recording layer. A reflective layer formed on the reflective layer, and a protective film formed on the reflective layer and protecting the recording layer and the reflective layer, and closer to the protective film than the recording layer of the flexible optical disc It has a layer made of a ferromagnetic foil.

  When the flexible optical disk is configured in this manner, the flexible optical disk can be fixed to the holder that attracts the ferromagnetic foil provided on the flexible optical disk by magnetism so as to be peeled off. Information can be recorded or reproduced in the same manner as a conventional optical disk by setting the flexible optical disk together with a holder to which the flexible optical disk is fixed to an existing recording / reproducing apparatus.

  Further, in the flexible optical disc according to the present invention, the recording layer is formed by forming concave pits in a resin layer applied to the film base material, and the reflective layer is formed by the ferromagnetic foil closing the concave pits. It is characterized by.

  A flexible optical disk is formed by closing the opening of a recess formed by a roll-to-roll method on a resin layer applied to one surface of a film base with a reflective layer, and an air layer and a resin layer formed inside the recess. In the case where information is recorded by so-called air pits using the difference in refractive index, a metal thin film reflective layer covering the opening of the recess can be formed of a ferromagnetic foil. By doing so, the flexible optical disk can be fixed to the holder so that it can be peeled off by being attracted to the magnetism of the holder by the reflection layer, which is a ferromagnetic foil.

  Furthermore, the holder for flexible optical disks according to the present invention is a holder for flexible optical disks that releasably supports the flexible optical disk according to claim 1 or 2, and includes a magnet for adhering the ferromagnetic foil. It is characterized by.

  By configuring the flexible optical disk holder in this manner, the flexible optical disk according to claim 1 or 2 can be easily fixed to the holder.

  When the flexible optical disk according to the present invention and the flexible optical disk holder are attached together by magnetism, it can be made the same size as an ordinary optical disk (outer diameter 120 mm, inner diameter 15 mm, thickness 1.2 mm). Recording or reproduction can be performed with the optical disc drive. In addition, the flexible optical disk can be easily attached / detached as compared with an adhesive type or mechanical claw type holder, and can be used repeatedly without causing distortion due to repeated attachment / detachment. Also, errors during recording or reproduction due to dust adhesion, scratches, dirt, etc. can be reduced.

A flexible optical disk according to an embodiment of the present invention and a flexible optical disk holder to which the flexible optical disk is mounted will be described with reference to FIGS.
The flexible optical disk of this embodiment is a flexible optical disk 1 applied to a Blu-ray Disc-ROM (BD-ROM).

As shown in FIG. 1, the flexible optical disk 1 is formed in a thin disk shape as a whole, and a circular alignment hole 2 penetrating the disk is formed at the center. As shown in the cross-sectional view of FIG. 1, the flexible optical disc 1 includes a film base 3, a resin layer 4 laminated on one surface of the film base 3, and a surface of the resin layer 4. The reflective layer 5 is made of a ferromagnetic foil, and a protective film 6 laminated on the surface of the reflective layer 5.
A plurality of recesses 7 are formed in the resin layer 4, and the reflective layer 5 is stretched so as to close the opening of the recess 7, thereby forming a closed space portion inside the recess 7. A recessed pit 9 is provided.

In the flexible optical disk 1 formed in this way, as shown in FIG. 2, the signal can be read by the optical optical path length difference 19 generated by the difference in refractive index between the concave pit 9 and the resin portion 17.
Further, by performing the work of bonding the nickel foil reflective layer 5 and the pit transfer film 15 in an inert gas atmosphere such as nitrogen or argon, the recessed pits 9 are filled with an inert gas, which is more reliable. Discs can be made.
The resin layer 4 in which the concave pits 9 are formed is a recording layer 11.

  On the other hand, the holder 21 as a whole is formed in a disc shape that is thicker than the flexible optical disc 1, and includes an alignment guide 22 that is formed so as to protrude from the center of one surface. The diameter of the alignment hole 2 of the flexible optical disc 1 is slightly larger than the diameter of the alignment guide 22, and the flexible optical disc 1 is mounted on the holder 21 by fitting the alignment hole 2 to the alignment guide 22. Is done.

  As shown in FIG. 3, the holder 21 is formed in a three-layer shape having a disk-shaped magnet 27 inside a disk-shaped case 26 formed of a plastic or the like, and an alignment guide at the center thereof. A center hole 24 having a diameter smaller than 22 is formed so as to penetrate the thickness of the holder 21, and a spindle shaft of the optical disc drive apparatus is fitted into the hole 24.

  In this way, the flexible optical disk 1 and the holder 21 are configured, and fitted into the alignment guide 22 of the holder 21 while being aligned by the alignment hole 2 of the flexible optical disk 1, and between the ferromagnetic reflective film 5 and the magnet 27. When the flexible optical disk 1 is fixed to the holder 21 by the pulling force, the thickness of the flexible optical disk 1 can be adjusted to the same thickness as that of a normal optical disk, and can be recorded or reproduced by a normal optical disk drive device.

In addition, since the flexible optical disk 1 and the holder 21 are only fixed by the force of the magnet 27, the flexible optical disk 1 can be easily detached from the holder 21, and distortion due to attachment / detachment is not likely to occur. Can do.
Further, since the flexible optical disk 1 can be easily attached to and detached from the holder 21, scratches and dirt are hardly attached, and dust may adhere as in the case where the flexible optical disk 1 is bonded to the holder 21 using an adhesive. Therefore, errors during recording or reproduction can be reduced.

A polycarbonate having a thickness of 90 μm is used as the film substrate 3, and 0.05 Pa · s of an acrylic UV curable resin is applied to the surface with a thickness of about 10 μm to form a resin layer 4.
The type of the film substrate 3 is preferably a material that has good adhesion to the acrylic ultraviolet curable resin of the resin layer 4, low birefringence, and transmits ultraviolet rays. For example, acrylic (PMMA), triacetyl cellulose (TAC) Etc. are appropriate.

  The type of UV curable resin of the resin layer 4 is a resin that undergoes a radical polymerization reaction and is an acrylic resin having an acryloyl group in the molecule, and an epoxy acrylate, urethane acrylate, polyester acrylate, polyol acrylate oligomer or polymer. 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, Monomers, oligomers, polymers such as trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate A mixture of can be used. The thickness is preferably 5 to 50 μm, and the viscosity is preferably about 0.003 to 0.5 Pa · s before UV curing.

  Next, using the stamper wound around the cylinder, the resin layer 4 and the stamper surface of the cylinder are pressure-bonded, cured by irradiating with ultraviolet rays on the flat surface, and peeled while being held by a peeling roll, thereby transferring the pits. Film (hereinafter referred to as a pit transfer film) 15. 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 that has been subjected to adhesive processing is bonded to the pit transfer film 15 as the reflective film 5. The foil for the reflective layer 5 may be made of a ferromagnetic material having an appropriate reflectance with respect to the recording / reproducing laser wavelength. Specifically, any one of cobalt (Co), nickel (Ni), and iron (Fe), or any of cobalt (Co), nickel (Ni), and iron (Fe) Alloys containing are preferred.

  On the other hand, if the thickness of the ferromagnetic foil for the reflective layer 5 is too thin, a sufficient tensile force may not be obtained between the magnet 27 of the holder 21 and if it is too thick, the thickness and weight of the flexible optical disc 1 as a whole. Is preferably 5 to 100 μm, and the strength for reading the signal with the optical optical path length difference 19 generated by the difference in refractive index between the concave pit 9 and the resin portion 17 is further preferred. The smoothness (Ra) of the surface of the magnetic foil is required to be 3 nm or less, and preferably 1 nanometer nm.

  When the pit transfer film 5 bonded to the nickel foil reflection film 7 having such a structure is applied to a Blu-ray disc, the wavelength of the laser used for recording and reproduction is 405 nm, and the resin refractive index of the resin layer is about 1.5. Considering that the refractive index of air is about 1.0, the depth of the recessed pit 9 is preferably 50 to 150 nm.

Further, a polycarbonate film having a thickness of 50 μm was bonded as the protective film 13, and the thickness of the entire disk was 180 μm, and punched out to an outer diameter of 119 mm and an inner diameter of 30 mm.
The outer diameter of the flexible optical disk 1 only needs to be equal to or smaller than the value determined in the disk standard, and the inner diameter is made several tens of micrometers larger than the diameter of the alignment guide 22 of the holder 21. When applied to a Blu-ray disc, the outer diameter is preferably 118 to 120 mm, and the inner diameter is preferably 20 to 40 mm.

As shown in FIG. 4, the holder 21 has an outer shape of 120 mm, a center hole diameter of 15 mm, and a thickness of 1.02 mm. The holder alignment guide 22 has a height of 0.2 mm and an outer diameter of a flexible optical disk. It is necessary to make the diameter of one center hole 24 smaller by several tens of micrometers.
Further, it is preferable that the magnetic force of the magnet 27 built in the holder 21 is blocked by the nickel foil of the reflective layer 5 and does not affect the operation of the pickup unit.

  As described above, by mounting the flexible optical disc 1 according to the present invention on the holder 21, the size can satisfy the standard value of the Blu-ray disc, and recording / reproduction with a general Blu-ray disc drive is possible. I was able to.

  The magnet 27 built in the holder 21 is preferably shaped so as to cover the entire surface as shown in FIG. 4, but may be arranged only partially as shown in FIG. 5 depending on the strength of the magnetic force.

  In the embodiment and examples described above, the recording layer 11 of the flexible optical disk 1 is constituted by the recessed pits 9 and the resin layer 4 which are spaces inside. However, as shown in FIG. A reflection layer 31 is formed on the pit transfer film 15 having irregularities formed thereon by sputtering, vapor deposition, or the like, and a recording layer 32 of a method of reading a signal by the effect of canceling the reflected light using the optical path length difference 19 depending on the presence or absence of the pit 34. But it ’s okay. In this case, it is necessary to affix the ferromagnetic foil 33 to the surface of the protective film 6 as shown in FIG.

Cross section of flexible optical disk according to the present invention Signal read conceptual diagram of flexible optical disk shown in the embodiment Sectional drawing of the state which mounted the flexible optical disk by this invention in the holder Holder top view Holder top view General optical disk signal reading concept

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flexible optical disk 2 ... Position alignment hole 3 ... Film base material 4 ... Resin layer 5 ... Reflective layer (ferromagnetic substance foil)
6 ... Protective film 7 ... Concave 9 ... Concave pit 11 ... Recording layer 15 ... Pit transfer film 17 ... Resin part 19 ... Optical path length difference 21 ... Holder 22 ... alignment guide 24 ... center hole 26 ... case 27 ... magnet 31 ... reflective layer 32 ... recording layer 33 ... ferromagnetic foil 34 ... pit

Claims (3)

A flexible optical disk that has flexibility and is used by being stacked on a disk-shaped holder,
A recording layer formed on one surface of the film substrate;
A reflective layer formed on the recording layer;
A protective film that is formed on the reflective layer and protects the recording layer and the reflective layer,
A flexible optical disk comprising a layer made of a ferromagnetic foil on the protective film side of the recording layer of the flexible optical disk. The recording layer is formed by forming concave pits in the resin layer applied to the film substrate,
The flexible optical disk according to claim 1, wherein the reflective layer is made of the ferromagnetic foil that closes the recessed pits. A holder for a flexible optical disk that releasably supports the flexible optical disk according to claim 1 or 2,
A flexible optical disk holder comprising a magnet for adhering the ferromagnetic foil.

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