US20010046203A1 - Optical disc and method for manufacturing same - Google Patents
Optical disc and method for manufacturing same Download PDFInfo
- Publication number
- US20010046203A1 US20010046203A1 US09/226,701 US22670199A US2001046203A1 US 20010046203 A1 US20010046203 A1 US 20010046203A1 US 22670199 A US22670199 A US 22670199A US 2001046203 A1 US2001046203 A1 US 2001046203A1
- Authority
- US
- United States
- Prior art keywords
- curable resin
- substrate
- optical disc
- light transmitting
- rotation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 141
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title description 37
- 239000000758 substrate Substances 0.000 claims abstract description 157
- 239000011347 resin Substances 0.000 claims description 146
- 229920005989 resin Polymers 0.000 claims description 146
- 239000011248 coating agent Substances 0.000 claims description 20
- 238000000576 coating method Methods 0.000 claims description 20
- 239000011358 absorbing material Substances 0.000 claims description 2
- 238000002347 injection Methods 0.000 claims 1
- 239000007924 injection Substances 0.000 claims 1
- 239000010410 layer Substances 0.000 description 142
- 239000010408 film Substances 0.000 description 15
- 239000011521 glass Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 6
- 238000005286 illumination Methods 0.000 description 5
- 230000001681 protective effect Effects 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000001746 injection moulding Methods 0.000 description 4
- 238000001659 ion-beam spectroscopy Methods 0.000 description 4
- 239000012782 phase change material Substances 0.000 description 4
- 238000004528 spin coating Methods 0.000 description 4
- 206010010071 Coma Diseases 0.000 description 3
- 230000004075 alteration Effects 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 230000001012 protector Effects 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- 229910000618 GeSbTe Inorganic materials 0.000 description 1
- 230000005374 Kerr effect Effects 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052752 metalloid Inorganic materials 0.000 description 1
- 150000002738 metalloids Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000005411 photomagnetism Effects 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 230000009993 protective function Effects 0.000 description 1
- 238000001552 radio frequency sputter deposition Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/254—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of protective topcoat layers
- G11B7/2542—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of protective topcoat layers consisting essentially of organic resins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D17/00—Producing carriers of records containing fine grooves or impressions, e.g. disc records for needle playback, cylinder records; Producing record discs from master stencils
- B29D17/005—Producing optically read record carriers, e.g. optical discs
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
- G11B7/2531—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising glass
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
- G11B7/2533—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/254—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of protective topcoat layers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
- G11B7/266—Sputtering or spin-coating layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2009/00—Layered products
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
- G11B2007/24304—Metals or metalloids group 2 or 12 elements (e.g. Be, Ca, Mg, Zn, Cd)
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B7/2433—Metals or elements of groups 13, 14, 15 or 16 of the Periodic System, e.g. B, Si, Ge, As, Sb, Bi, Se or Te
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
- G11B7/2533—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins
- G11B7/2534—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins polycarbonates [PC]
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/257—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
- G11B7/2578—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/258—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of reflective layers
- G11B7/2585—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of reflective layers based on aluminium
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Manufacturing Optical Record Carriers (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
Abstract
An optical disc and its manufacturing method in which humps may be prohibited from being formed on an outer rim area of the disc to assure optimum surface properties of a light transmitting layer of the disc to contribute to further increase in recording capacity. On a substrate 2 of an optical disc 1 are sequentially formed a recording portion 6 and a light transmitting layer 5. The light falls on the light transmitting layer 5 to record and/or reproduce information signals for a signal recording area 6 a of the substrate 2. The radial distance D from the outermost rim of the substrate 2 to the signal recording area 6 a is selected to be larger than the radial width L of a hump 5 a formed on the outer rim of the light transmitting layer 5. The hump 5 a has a height h from the surface of the light transmitting layer 5 not larger than 70 μm.
Description
- 1. Field of the Invention
- This invention relates to an optical disc having a substrate and a recording layer and a light transmitting layer formed in this order thereon and which is adapted for recording and/or reproducing information signals on the recording layer by the light incident on the light transmitting layer.
- 2. Description of the Related Art
- Among optical recording mediums for audio or video, adapted for recording the various information thereon, there are, for example, an optical disc on which information signals are pre-recorded by embossed pits, a phase-change disc on which information signals are written by exploiting phase changes of the recording film, and a magneto-optical disc on which information signals are written by exploiting the photomagnetic effect of the recording film. With this type of the optical recording medium, a recording layers, a light reflecting layer and a protective layer are sequentially formed on a transparent substrate, and the laser light is adapted to fall from the transparent substrate side for recording and/or reproducing information signals on the recording layer.
- Meanwhile, with the conventional optical disc, the recording density of the optical disc is determined by the minimum spot diameter of a laser light source employed. That is, the smaller the laser spot diameter, the higher is the recording density that can be achieved. This laser spot diameter is proportionate to the {fraction (λ/NA)} of the of the recording/reproducing optical system, where λ is the wavelength of the laser light and NA is the numerical aperture of an objective lens. Thus, if desired to realize high recording density of the optical disc, the wavelength λ of the laser light needs to be reduced to increase the numerical aperture of the objective lens.
- However, if the numerical aperture of the objective lens is increased, coma aberration poses a problem, since coma aberration is proportionate to [skew angle, that is the tilt angle of the objective lens to the optical axis of the optical disc]×NA3×[thickness of the optical disc traversed by the laser light]. For tackling with this problem of coma aberration, a method of reducing the thickness of the transparent substrate, as a disc substrate, is under consideration.
- However, for the transparent substrate of the optical disc, an injection-molded substrate of plastics, produced by the injection molding method, is predominantly used. It is technically difficult to fabricate the injection-molded substrate to an extremely thin thickness and to high precision. The method for improving the recording density of the conventional optical disc by reducing the wavelength λ of the laser light or by enlarging the numerical aperture of the objective lens is, as it were, approaching a technically unsurmountable limit level.
- The present inventors have proposed an optical disc in which, for possibly improving the recording density further, a light reflecting layer, a recording layer and a light transmitting layer are sequentially formed on a substrate and the laser light is caused to fall from the light transmitting layer to record and/or reproduce information signals on a signal recording area of the signal recording layer.
- In particular, since the optical disc is fabricated by sequentially forming the light reflecting layer, recording layer and the light transmitting layer on the substrate, the light transmitting layer on which falls the laser light can be manufactured to a thin thickness and to high accuracy. The result is that the optical disc can sufficiently cope with the high NA of the objective lens to improve the recording density.
- The methods for forming the light transmitting layer on the optical disc may be exemplified by a first method of sequentially forming a light reflecting layer and a recording layer on a substrate and subsequently affixing a
resin sheet 100 μm in thickness on the recording layer via a transparent adhesive layer several μm in-between to form a light transmitting layer formed by the resin sheet, and a second method of dripping a UV curable resin on the recording layer and stretching the UV curable resin on rotation and illuminating the UV rays on the substrate kept in a stationary state to cure the resin to form the light transmitting layer. - With the first method, the light transmitting layer exhibits optimum thickness evenness. However, this light transmitting layer is difficult to manufacture with respect to handling of the resin sheet and double refraction and hence it has scarcely put to practical use.
- With the second method, a center opening in the substrate is temporarily stopped and, in this state, a UV curable resin is dripped onto this center hole and stretched on rotation. The substrate is then kept in a stationary state and irradiated with the UV rays to cure the UV curable resin to form the light transmitting layer. Since this second method represents further development of the technique of forming a protective film for a conventional optical disc, such as compact disc (CD), and hence the stock handling, know-how in coating and designing of the apparatus so far developed can be utilized, it lends itself to mass production.
- However, with this second method, in which the UV curable resin is stretched on rotation, the resin tends to be moved towards the outer rim during the stretching process under the centrifugal force, so that a protuberant portion tends to be produced in an outer rim portion. Moreover, with this second method, since the UV rays are illuminated on the
substrate 101 coated with the UV curable resin by rotational stretching, as the substrate is kept stationary, the resin deposited on the outer rim portion is raised and reverted towards the inner rim side under the surface tension to form ahumped portion 100 of a sizeable width, as a result of which thelight transmitting layer 102 presents ahump 100 on its outer rim portion. - If the UV curable resin s coated to a film thickness of 100 μm on the substrate of the same size as the conventional CD, with the substrate being then rotated for stretching the resin and then being halted to illuminate the UV rays to form the light transmitting layer thereon, there is formed a humped portion in the outer rim area having a radial width of 5 mm or more, thus narrowing the signal recording area.
- If the humped portion having a width sufficient to affect the signal recording area is formed in this manner on the outer rim area of the light transmitting layer, a sufficient signal recording area cannot be obtained to render it impossible to improve the recording capacity or to lead possibly to reduced recording capacity. Specifically, for realizing the high recording capacity, it is necessary to procure a signal recording area comparable to that of the CD or DVD. In order to achieve this, the humped portion formed on the outer rim of the light transmitting layer needs to be of a width of not larger than 1.5 mm.
- It is therefore an object of the present invention to provide an optical disc that can be increased further in recording capacity and that has a light transmitting layer of optimum surface properties free to the utmost extent from humps on its outer rim portion, and method for manufacturing such optical disc.
- In one aspect, the present invention provides an optical disc in which a recording layer and a light transmitting layer are sequentially formed on a substrate and in which light is incident from the side of the light transmitting layer to record and/or reproduce information signals for a signal recording area of the recording layer, wherein a radial distance from the outermost area of the substrate to signal recording area is selected to be larger than a radial width of a hump produced on the outer rim of the light transmitting layer and wherein the height of hump from the surface of the light transmitting layer is 70 μm or less.
- The optical disc of the present invention, in which the width and the height of a hump formed at an outer rim of the light transmitting layer following the manufacture of the disc are limited as described above, has optimum surface properties by having the light transmitting layer free from surface irregularities as far as possible to provide a signal recording area as broad as possible.
- In another aspect, the present invention provides a method for producing an optical disc in which a recording layer and a light transmitting layer are sequentially formed on a substrate and in which light is incident from the side of the light transmitting layer to record and/or reproduce information signals, including the steps of coating, at the time of forming the light transmitting layer, a UV curable resin on the portion of the substrate carrying recording layer and rotating the substrate carrying the UV curable resin coated thereon and concurrently illuminating UV rays on UV curable resin to cure UV curable resin.
- With the optical disc manufacturing method according to the present invention, UV rays are illuminated on the substrate, carrying the UV curable resin, as the disc is run in rotation, thus minimizing the risk of the UV curable resin on the outer rim of the substrate reverting to the inner rim under centrifugal force to produce a hump.
- FIG. 1 is a cross-sectional view of a typical optical disc embodying the present invention.
- FIG. 2 is an enlarged cross-sectional view of an outer rim of an optical disc embodying the present invention.
- FIG. 3 is a cross-sectional view showing a step of coating of a UV curable resin in the manufacturing method of an optical disc embodying the present invention.
- FIG. 4 is a cross-sectional view showing a step of illuminating UV rays on a UV curable resin in the manufacturing method of an optical disc embodying the present invention.
- FIG. 5 is a cross-sectional view showing a step of coating of a UV curable resin in the manufacturing method of an optical disc embodying the present invention.
- FIG. 6 is a cross-sectional view showing a step of setting a glass plate on the coated UV curable resin in the manufacturing method of an optical disc embodying the present invention.
- FIG. 7 is a cross-sectional view showing the state in which the UV curable resin is stretched on the entire surface of the recording layer formed on the substrate.
- FIG. 8 is a cross-sectional view showing a typical substrate having a cut-out in its outer rim portion and which is used in the manufacturing method of the optical disc embodying the present invention.
- FIG. 9 is a cross-sectional view showing a step of illuminating deep UV only in the outermost rim portion of the substrate carrying the recording layer in the manufacturing method of the optical disc embodying the present invention.
- FIG. 10 is a cross-sectional view showing a step of illuminating UV rays only on the UV curable resin positioned on the signal recording area in the manufacturing method of the optical disc embodying the present invention.
- FIG. 11 is a cross-sectional showing a step of exfoliating a mask and rotating the substrate at an elevated speed following the step shown in FIG. 10.
- FIG. 12 is a cross-sectional view showing a step of mounting a ring on the outer rim of the substrate in the manufacturing method of the optical disc embodying the present invention.
- FIG. 13 is a cross-sectional view showing a step of coating a UV curable resin on a substrate carrying the ring and the recording layer following the step of FIG. 12.
- FIG. 14 is a cross-sectional view showing a step of illuminating UV rays on the UV curable resin following the step shown in FIG. 13.
- FIG. 15 is a cross-sectional view showing a step of removing the ring and the UV curable resin thereon following the step shown in FIG. 13.
- FIG. 16 is a cross-sectional view showing a step of forming a light transmitting layer using a substrate larger in size than a routine substrate as an optical disc manufacturing method embodying the present invention.
- FIG. 17 is an enlarged cross-sectional view showing an outer rim portion of a conventional optical disc.
- Referring to the drawings, preferred embodiments of the present invention will be explained in detail. FIG. 1 shows a typical optical disc embodying the present invention.
- An
optical disc 1, embodying the present invention, has a light reflecting layer 3, arecording layer 4 and a light transmittinglayer 5, layered in this order on asubstrate 2. The light reflecting layer 3 and therecording layer 4 make up asignal recording layer 6. With the presentoptical disc 1, light is caused to fall on the light transmittinglayer 5 to record and/or reproduce information signals for thesignal recording layer 6. - On a
major surface 2 a of thesubstrate 2 are formed fine crests and valleys, such as recording grooves or pre-grooves, for recording signals, such as information signals. Thesubstrate 2 preferably has a thickness of 0.3 to 1.2 mm. The materials of thesubstrate 2 may be enumerated by plastics, including acrylic resins, such as polycarbonate or polymethyl methacrylate (PMMA), and glass. The substrate is molded by injection molding and by a photopolymer (2P) method in the former and latter cases, respectively. - The light reflecting layer3, formed on the crests and valleys on the
major surface 2 a of thesubstrate 2, operates not only as a reflecting layer for reflecting the light transmitted through therecording layer 4, but also as a heat sink layer for preventing heat from being generated excessively in therecording layer 4. - The light reflecting layer3 is preferably formed of elements metal, metalloids, semiconductor elements, which may be used singly or in combination.
- Most preferred is a material mainly composed of Al and containing 0.4 to 0.8 wt % of Si, not more than 0.7 wt % of Fe, 0.15 to 0.40 wt % of Cu, not more than 0.15 wt % of Fe, 0.8 to 1.2 wt % of Mg, 0.04 to 0.35 wt % of Cr, not more than 0.25 wt % of Zn and not more than 0.15 wt % of Ti. The light reflecting layer3 is formed as a thin film having a thickness of 50 to 200 nm.
- The above material is preferred in that, if a phase-change recording layer formed of a phase change material is layered as a
recording layer 4 on the light reflecting layer 3, the phase-change recording layer is affected to a lesser extent by the crystallinity of the light reflecting layer 3 or by the interface formed by the crystal grains of the light reflecting layer 3, as a result of which the phase change recording layer correctly reflects the surface state of thesubstrate 2. - The methods for forming the light reflecting layer3 of the above-mentioned material on the
substrate 2 may be enumerated by an ion beam sputtering method, a dc sputtering method and an RF sputtering method. Of these, the ion beam sputtering method is most preferred. - The
recording layer 4 is an optical recording layer for which information signals can be written or erased by illumination of the laser light. This recording layer may be formed of a phase-change material undergoing reversible phase change between crystal and amorphous phases or of a photomagnetic recording material which loses coercivity on temperature increase beyond the Curie temperature to undergo inversion of magnetization to the direction of the external magnetic field. - As a photomagnetic recording layer, there is used a perpendicular magnetic recording film exhibiting photomagnetic characteristics, including Kerr effect or the Faraday effect, such as an amorphous alloy thin film, exemplified by Tb—Fe—Co thin film.
- In the case of a read-only optical disc, a pre-set pattern of lands and recesses corresponding to a signal pattern is formed on the
substrate 2. The recording area is completed by coating the pattern of lands and recesses with the light reflecting layer 3. - The laser light falls on the
light transmitting layer 5 at the time of recording/reproduction of information signals. Thislight transmitting layer 5 also operates as a protective layer to prohibit therecording layer 4 from coming into contact with corrosive factors, such as moisture. - The
light transmitting layer 5 is formed by forming a UV curable resin on asignal recording portion 6 by a manufacturing method of the present invention as will be explained subsequently. - This
light transmitting layer 5 is preferably of a thickness of 3 to 177 μm in consideration that the lower limit of the thickness of thelight transmitting layer 5 is determined in dependence upon whether or not the protective function of the light transmitting layer performing the role of protecting therecording layer 4 or the light reflecting layer 3 can thereby be assured. That is, the thickness of thelight transmitting layer 5 not less than 3 μm is required in consideration of the reliability of the optical disc and the effect of collision of the objective lens on the surface of thelight transmitting layer 5. On the other hand, the maximum thickness of thelight transmitting layer 5 of 177 μm is desirable in consideration that the shorter wavelength of the laser light is realized in future such that the blue laser light thought to be promising in near future is to be coped with rather than the currently used red laser light. - Therefore, the thickness t of the
light transmitting layer 5 ranging between 3 μm and 177 μm is preferred. - The shape of the outer rim of the
optical disc 1 of the present invention, constructed as described above, is hereinafter explained. - FIG. 2 shows, in a cross-sectional view, the outermost rim of the
optical disc 1 of the present invention to an enlarged scale, without, however, showing the lands and recesses of thesignal recording portion 6. In thissignal recording portion 6, an area which actually is used for recording/reproducing the information signals is indicated as asignal recording area 6 a. - In particular, in the
optical disc 1 according to the present invention, a hump 5 a formed on the outer rim of thelight transmitting layer 5 following the end of the manufacturing process has a height h from the surface of thelight transmitting layer 6 equal to 70 μm or less. - For achieving high recording density of an optical disc, the
light transmitting layer 5 illuminated by the light is reduced in thickness, as in the optical disc embodying the present invention, or the numerical aperture NA of the objective lens of the optical pickup is increased. That is, if, in the optical disc in which the light is caused to fall from the side of thelight transmitting layer 5 for recording/reproducing the information signals, a higher recording density is to be achieved, an optical pickup having its objective lens of a higher NA value is to be used, as a result of which the working distance between the optical pickup and the optical disc is reduced. - Specifically, the working distance between the optical pickup and the optical disc is approximately 100 μm, depending on the designing of the optical pickup. This working distance is smaller by one digit of magnitude than that in a compact disc CD or a digital versatile disc DVD. Thus, the optical disc is more susceptible to collision against the optical pickup than the conventional CD or DVD. For reducing the damage possibly inflicted to the optical pickup by such collision, there is provided a protector at a distal end of the usual optical pickup opposite to the optical disc. This protector is mounted at a distance of approximately 30 μm from the optical pickup.
- Therefore, the height of a hump, inevitably formed on the readout surface of the optical disc for the reason pertinent to the optical disc manufacture, needs to be suppressed to be 70 μm or less.
- That is, with the optical disc embodying the present invention, in which the height h of the hump5 a formed on the outer rim of the
light transmitting layer 5 is set so as to be not larger than 70 μm, it is possible to avoid the phenomenon of the optical pickup and the optical disc colliding against each other even if the objective lens has an enlarged numerical aperture NA to meet the requirement for high recording density and thus the distance between the optical disc and the optical pickup, that is the working distance, is reduced. Therefore, theoptical disc 1 embodying the present invention is able to sufficiently meet the demand for the higher recording density. - As for the height h of the hump5 a of the
light transmitting layer 5, it is preferably not larger than approximately 20 μm, in consideration that contaminants such as dust and dirt tend to be affixed to the surface of the optical disc. It is because the dust and dirt tending to affect the recording/reproducing characteristics are usually of a size of 30 to 40 μm. - Also, with the optical disc according to the present invention, the radial distance from the outermost rim of the
substrate 2 to thesignal recording area 6 a is larger than the width in the radial direction of the hump 5 a formed on the outermost rim of the light transmitting layer. Thus, with theoptical disc 1, thesignal recording area 6 a can be enlarged effectively to increase the recording capacity further. - It is now assumed that the distance from the outermost rim of the
substrate 2 to thesignal recording area 6 a is D mm and that the width of the hump 5 a formed a the outermost rim of the optical disc is L mm. - Meanwhile, in the conventional compact disc, the diameter of the optical disc and that of the signal recording area are approximately 60 mm and approximately 58.5 mm, respectively. That is, with the conventional CD, the distance D from the outermost rim of the disc to the
signal recording area 6 a is approximately 1.5 mm. - Thus, for assuring a recording capacity of the inventive optical disc equivalent to that of the conventional CD, the width L of the hump5 a produced at the outermost rim of the
light transmitting layer 5 needs to be 1.5 mm or less. - In particular, since it is necessary with the optical disc according to the present invention to set the
signal recording area 6 a so as to be broader to achieve the recording capacity larger than that of the conventional CD, the distance D from the outermost rim of the disc to the s6 a needs to be approximately 1.0 mm. - Thus, with the optical disc, a larger recording capacity can be achieved if the width L of the hump5 a at the outermost rim of the
light transmitting layer 5 is 1.0 mm or less. - Also, with the present
optical disc 1, the relation of D−0.5≧L mm is preferably met. That is, the difference between the distance D from the outermost rim of the disc to thesignal recording area 6 a and the width L of the hump 5 a at the outermost rim of thelight transmitting layer 5 is preferably not less than 0.5 mm. The reason is that, in this case, the hump 5 a affects the recording or reproducing characteristics to the least extent to assure optimum recording/reproducing characteristics of theoptical disc 1. - That is, with the present
optical disc 1, the signal recording area can be increased to assure a larger recording capacity. Also, with the presentoptical disc 1, in which thelight transmitting layer 5 is formed which has optimum surface properties and which is thin in film thickness, the light falls from the side of thelight transmitting layer 5 for recording/reproducing information signals for thesignal recording portion 6, the high NA of the objective lens and high recording density can be sufficiently coped with. Moreover, theoptical disc 1 has stable recording/reproducing characteristics and hence high operational reliability. - The method for fabricating the
optical disc 1 constructed as described above is hereinafter explained in detail. - For manufacturing the
optical disc 1,substrate 2, having a pre-set pattern of lands and recesses formed thereon in meeting with the guide groove or the information signals, is fabricated by an injection molding method. - Then, a light reflecting layer3 is formed to a film thickness of 150 nm on the
substrate 2, by an ion beam sputtering method, using a material mainly composed of Al and containing 0.4 to 0.8 wt % of Si, not more than 0.7 wt % of Fe, 0.15 to 0.40 wt % of Cu, not more than 0.15 wt % of Mn, 0.8 to 1.2 wt % of Mg, 0.04 to 0.35 wt % of Cr, not more than 0.25 wt % of Zn and not more than 0.15 wt % of Ti. This film-forming method by ion beam sputtering gives an optical disc having signal properties better than those of the method by dc sputtering. - On the light reflecting layer3, thus formed, a first protective film of a dielectric material composed of a mixture of ZnS and SiO2, a film of a phase-change material, composed of GeSbTe, and a second protective film of a dielectric material, composed of ZnS and SiO2, are sequentially layered to complete the
recording layer 4. - The film thicknesses of the first protective film, film of the phase-change material and the second protective film are 20 nm, 25 nm and 100 nm, respectively.
- Finally, a UV curable resin is formed on the
recording layer 4 by the spin coating method, now to be explained, to form thelight transmitting layer 5 with a film thickness of 0.1 mm, to fabricate theoptical disc 1. - For forming the
light transmitting layer 5 by the optical disc manufacturing method according to the present invention, a spin coating device, shown for example in FIG. 3, is used. Although thelight transmitting layer 5 is formed on thesubstrate 2 carrying therecording layer 4, thisrecording layer 4 is not shown in FIG. 3. - With the optical disc manufacturing method according to the present invention, the
substrate 2, carrying therecording layer 4, is arranged on aturntable 10 rotatably supported on a centerrotation supporting member 11. Thesubstrate 2 is arranged on theturntable 10 so that therecording layer 4 as a film-forming surface is opposite to the substrate surface contacted with theturntable 10. With the center opening portion of thesubstrate 2 being stopped by alid member 12, thesubstrate 2 is run in rotation a an rpm of 800 in the direction indicated by arrow A in the drawing and, under this condition, the UV curable resin is dripped in the direction indicated by arrow B in the drawing onto thelid member 12 disposed at the center of thesubstrate 2. Thesubstrate 2 is then set into rotation for stretching the UV curable resin over therecording layer 4 of thesubstrate 2. - Then, in the optical disc manufacturing method of the present invention, the rpm by the
rotation supporting member 11 is reduced to, for example, 400. As the substrate is rotated in this condition further, UV rays are illuminated on the resin coated on therecording layer 4 of thesubstrate 2. Finally, the UV curable resin is cured to form thelight transmitting layer 5. - The rpm for illumination of UV rays is preferably of the order of 40 to 50% or 40 to 60% of the rpm for stretching of the UV curable resin by rotation if the latter is approximately 1000 or less or not less than 1000, respectively.
- In the conventional spin coating method, the UV rays are illuminated while the
substrate 2 is stationary. However, with the optical disc manufacturing method according to the present invention, the UV rays are illuminated while thesubstrate 2 is kept in rotation. - With the optical disc manufacturing method according to the present invention, as described above, the light transmitting layer is manufactured by the spin coating method by dripping the UV curable resin on the
recording layer 4 of therotating substrate 2 for stretching the resin and by illuminating the UV rays on the UV curable resin, with thesubstrate 2 being kept in rotation at a reduced rpm. - That is, the optical disc manufacturing method according to the present invention is a method of illuminating the UV rays on the rotating substrate to cure the resin. Specifically, the UV curable resin is stretched on rotation on the
recording layer 4 on the substrate rotating at an rpm of 800 and subsequently the UV rays continue to be illuminated on the substrate 3 at a reduced 400 rpm. - An experimental example is now shown in which the optical disc is manufactured using an optical disc embodying the present invention.
- First, a substrate 120 mm in diameter was prepared by injection molding. On this substrate was dripped a UV curable resin 2200 cps in viscosity and stretched on rotation at 810 rpm to apply the UV curable resin to a thickness of 100 μm.
- As the substrate was kept rotating at 400 rpm, UV rays were irradiated thereon for 25 seconds to cure the resin to form the light transmitting layer to produce the ultimate optical disc.
- The optical disc, thus prepared, had the hump with a width L of approximately 3 mm on the outer rim of the light transmitting layer.
- The UV curable resin with a viscosity of 4500 cps was dripped on a similar substrate and coated thereon to a thickness of 100 μm on stretching by rotation at 1200 rpm. The substrate, run in rotation at 500 rpm, was irradiated with UV rays for 25 sec to cure the resin to form the light transmitting layer to produce the ultimate optical disc.
- The optical disc, thus prepared, had the hump with a width L of approximately 2 mm on the outer rim of the light transmitting layer.
- Thus, with the optical disc manufacturing method according to the present invention, in which the UV curable resin is cured as the substrate is kept in a rotating state, it is possible to suppress the phenomenon of the UV curable resin from reverting from the outer rim side to the inner rim side to produce a hump by surface tension as far as possible.
- Thus, with the present optical disc manufacturing method, such
optical disc 1 can be manufactured which has thelight transmitting layer 5 of optimum surface properties and an effectively broadsignal recording area 6 a and which can realize a further increased recording capacity. - Meanwhile, a glass plate may be set on the UV curable resin dripped prior to illuminating the UV rays prior to illumination of UV rays.
- Specifically, a UV
curable resin 14 is dripped on thesubstrate 2 set on theturntable 10, as shown in FIG. 5. At this time, thesubstrate 2 is kept in a stationary state. - Then, a
glass plate 15 is set on the UVcurable resin 14, as shown in FIG. 6. At this time, thesubstrate 2 is run in rotation along with theglass plate 15 to stretch the UVcurable resin 14 on the entire surface of therecording layer 4. - When the UV
curable resin 14 is stretched in this manner on the entire surface of therecording layer 4 on thesubstrate 2, UV rays 13 are illuminated on thesubstrate 2, kept in rotation along with theglass plate 15, to permit the UVcurable resin 14 to be cured to form thelight transmitting layer 5. Any excess UVcurable resin 14 is whirled off to prevent as much as possible the UV curable resin from being formed as a hump on the outer rim portions of thesubstrate 2. - Finally, the
glass palte 15 is peeled off from thelight transmitting layer 5 to produce theoptical disc 1. - By setting the
glass plate 15 in this manner on the UV curable resin, thelight transmitting layer 5 with optimum surface properties can be produced, because the smooth surface properties of theglass plate 15 are directly transferred to the producedlight transmitting layer 5. - For producing the optical disc according to the present invention, it is also possible to mold the outer rim of the
substrate 2 with a cut-out 2 a and to use thissubstrate 2 to perform the steps of coating the UV curable resin and the rotating and curing step as shown in FIGS. 3 and 4. If the height H of thesubstrate 2 is 1.2 mm, the cut-out 2 a may have a radial width W of 1.2 mm and an angle of 45°, as shown in FIG. 8. - By using the
substrate 2 having the cut-out 2 a pre-formed on its outer rim, the light transmitting layer can be produced which can effectively and readily suppress the generation of a humped portion on the outer rim of the substrate. With the present method, the cut-out 2 a can be formed during the molding thesubstrate 2 by a method similar to the method of forming the guide groove or the crests or valleys corresponding to the information signals during molding of thesubstrate 2. Thecutout 2 a may also be formed by etching following molding of theusual substrate 2. - In manufacturing the optical disc according to the present invention, UV rays may be illuminated on the outermost rim of the
substrate 2 before dripping the UV curable resin. Specifically, the portion of thesubstrate 2 excluding its outermost rim portion is covered by amask 16, before proceeding to drip the UV curable resin, and the so-called UV rays (UV rays of short wavelength ranging between 200 and 300 nm) are illuminated on the outermost rim of the disc. The outermost rim denotes an area lying radially outwardly of the signal recording area and specifically the outermost area of thesubstrate 2 and/or therecording unit 6. - The
mask 16 is peeled off and subsequently the steps of coating the UV curable resin and rotation/curing are carried out to form the ultimatelight transmitting layer 5. - With this method, since the UV rays of shorter wavelength are previously illuminated on the outermost portion of the
substrate 2, in which the hump is liable to be formed, in order to keep an optimum wetting properties of this outermost rim portion, it is possible to suppress the formation of the hump in the outermost rim of thelight transmitting layer 5 to the maximum extent possible to form thelight transmitting layer 5 of optimum surface properties. - In the optical disc manufacturing method according to the present invention, the
substrate 2 coated with the UV curable resin, obtained on dripping the UV curable resin and stretching it on rotation, may be run in rotation at an elevated rpm for a short time duration prior to illumination of UV rays. That is, the UV curable resin is dripped on thesubstrate 2 and stretched on rotation, after which therotation supporting member 11 is run in rotation at an elevated speed for short time duration. After running thesubstrate 2 in this manner for short time at an elevated rpm, the UV rays are illuminated as shown in FIG. 4 to perform the rotating curing step for the UV curable resin to form thelight transmitting layer 5. - By running the
substrate 2 in rotation at an elevated rpm before illumination of UV rays, it is possible to whirl off excess UV curable resin collected on the outer rim portion by the centrifugal force on stretching by rotation. - As a method for manufacturing the optical disc according to the present invention, it is also possible to illuminate UV rays first on the UV curable resin in the signal recording area, run the substrate at an elevated speed and to illuminate UV rays on the UV curable resin in an area other than the signal recording area.
- That is, after the UV curable resin is stretched by rotation on the
substrate 2, masks 17, 18 are applied to the UV curable resin lying on the UV curable resin in an area outwardly of thesignal recording area 6 a and in a center area of thesubstrate 2 and UV rays are illuminated on thesubstrate 2 kept in a rotating state. Since the area of thesubstrate 2 outwardly of thesignal recording area 6 a is coated by themask 17, only the UV curable resin which later becomes thesignal recording area 6 a is illuminated and cured by the UV rays. - The
mask 17 is then peeled off and thesubstrate 2 then is run in rotation at an elevated rpm. This whirls off excess UV curable resin lying on the outer rim of the substrate. - The rotation of the
substrate 2 is further continued as the rpm of therotation supporting member 11 is decreased to perform the rotation curing of the UV curable resin shown in FIG. 4 to form thelight transmitting layer 5. - After illuminating the UV curable resin on the
signal recording area 6 a, the substrate is run in rotation at an elevated rpm UVcurable resin 14 to whirl off excess UV curable resin and UV rays are illuminated on the UVcurable resin 14 on the outer rim to produce thelight transmitting layer 5 having of optimum surface properties easily and effectively. This method enables the excess UV curable resin on the outer rim to be whirled off more selectively than is possible with the above-described method of running the substrate in rotation at an elevated speed to whirl off excess resin from the outer rim without applying masks following stretching by rotation of the UV curable resin. - As the optical disc manufacturing method according to the present invention, it is also possible to use a
ring 20 having the same inner diameter as the outer diameter of the manufactured optical disc and the substantially same thickness as the thickness of the optical disc. In this method, thesubstrate 2 is fitted in the center hole of thering 20. - As the
substrate 2 is run in rotation along with thering 20 in the direction indicated by arrow A in FIG. 13, a UVcurable resin 21 is dripped to stretch the resin on rotation. - The
rotation supporting member 11 is kept rotating at a reduced rpm to run thesubstrate 2 along with thering 20 to illuminate UV rays on the UVcurable resin 21 to cure the resin. - Finally, the
ring 20 is dismounted to remove the UV curable resin formed thereon to complete theoptical disc 1. - In this manner, the
ring 20 is first fitted on the outer rim of thesubstrate 2, and UV curable resin is coated and cured on thering 20 and thesubstrate 2. Thering 20 is then dismounted and the UV curable resin thereon is removed to manufacture the optical disc of optimum surface properties freed of surface irregularities, such as humps, to the maximum extent possible. Since the UV curable resin on the outer rim liable to produce surface humps is not used in the present method as the light transmitting layer, the optical disc produced is of optimum surface properties. - With the optical disc manufacturing method according to the present invention, it is possible to use a substrate having an outer diameter slightly larger than the outer diameter of the usual substrate. Specifically, a
substrate 22 having a diameter slightly larger than the outer diameter of the usual substrate is used and, after a recording portion is formed thereon, thesubstrate 22 is kept in rotation to allow the UV curable resin to be cured as shown in FIGS. 3 and 4 to produce alight transmitting layer 23 having a diameter slightly larger than the outer diameter of the usual substrate shown in FIG. 16. Finally, thelight transmitting layer 23 and an excessouter rim 25 of thesubstrate 22 are cut off to give the same size as the usual substrate size, as indicated by arrow c in FIG. 16, to produce theoptical disc 1. - With the present method, in which a light transmitting layer of a larger diameter is previously formed and an excess portion of the light transmitting layer on the outer rim is cut off following curing on rotation, the UV curable resin on the outer rim portion liable to form humps is not used as the light transmitting layer, this realizing optimum surface properties.
- With the optical disc manufacturing method according to the present invention, it is also possible to get the UV curable resin stretched by rotation on the entire surface on the
substrate 2, to wipe off excess UV curable resin on the outermost rim portion by a resin-absorbing material, such as cloth, before curing the resin, and to then perform the rotating curing step of the UV curable resin, as shown in FIG. 4. - With the optical disc manufacturing method according to the present invention, it is also possible to get the UV curable resin stretched by rotation on the entire surface on the
substrate 2, to suck excess UV curable resin on the outermost rim portion by a vacuum pump etc, before curing the resin, and to then perform the rotating curing step of the UV curable resin, as shown in FIG. 4. - With the optical disc manufacturing method according to the present invention, it is also possible to get the UV curable resin stretched by rotation on the entire surface on the
substrate 2, to blow off excess UV curable resin on the outermost rim portion by nitrogen blowing etc, before curing the resin, and to then illuminate UV rays on therotating substrate 2, as shown in FIG. 4. - In the optical disc manufacturing method according to the present invention, it is desirable to use the UV curable resin of low surface tension since this permits the UV curable resin on the outer rim area to revert t the inner rim area to suppress formation of humps as far as possible.
- Also, in the optical disc manufacturing method according to the present invention, it is desirable to use a UV curable resin of higher viscosity.
Claims (18)
1. An optical disc in which a recording layer and a light transmitting layer are sequentially formed on a substrate and in which light is incident from the side of the light transmitting layer to record and/or reproduce information signals for a signal recording area of the recording layer, wherein
a radial distance from the outermost area of the substrate to said signal recording area is selected to be larger than a radial width of a hump produced on the outer rim of the light transmitting layer and wherein
the height of said hump from the surface of the light transmitting layer is 70 μm or less.
2. The optical disc according to wherein the height of said hump from the surface of the light transmitting layer is 20 μm or less.
claim 1
3. The optical disc according to wherein, with a radial distance from the outermost rim to the signal recording area of said substrate of D mm and a radial width of said hump formed at the outer rim of the light transmitting layer of L mm, the relation
claim 1
D−0.5≧L mm
is met.
4. The optical disc according to wherein the radial width of said hump 1 is 1.5 mm or less.
claim 1
5. The optical disc according to wherein the radial width of said hump 1 is 1.0 mm or less.
claim 1
6. A method for producing an optical disc in which a recording layer and a light transmitting layer are sequentially formed on a substrate and in which light is incident from the side of the light transmitting layer to record and/or reproduce information signals, comprising the steps of:
coating, at the time of forming the light transmitting layer, a UV curable resin on the portion of the substrate carrying said recording layer; and
rotating the substrate carrying the UV curable resin coated thereon and concurrently illuminating UV rays on said UV curable resin to cure said UV curable resin.
7. The method for producing an optical disc according to wherein said step of coating the UV curable resin drips the UV curable resin on a substrate carrying the recording layer and running the substrate in rotation to get the UV curable resin cured on rotation; and wherein said step of curing the UV curable resin runs the substrate carrying the UV curable resin coated thereon in rotation at an rpm smaller than the rpm of rotation of the substrate at the UV curable resin coating step and illuminates UV rays on said UV curable resin.
claim 6
8. The method for producing an optical disc according to wherein said step of coating the UV curable resin drips the UV curable resin on a substrate carrying the recording layer and subsequently sets a light-transmitting plate on the UV curable resin to get said UV curable resin stretched; and wherein
claim 7
said step of curing the UV curable resin runs the substrate and the light-transmitting plate in rotation and concurrently illuminating UV rays on said UV curable resin;
said light-transmitting plate being peeled off after the end of curing of said UV curable resin.
9. The method for producing an optical disc according to wherein a cut-out is formed in the outer rim of said substrate, with a spacing defined by said cut-out being used for accommodating a hump of said UV curable resin.
claim 6
10. The method for producing an optical disc according to further comprising the step of:
claim 6
running the substrate in rotation at an rpm larger than the rpm of said substrate used for coating said UV curable resin, said rotation step being carried out after the step of coating the UV curable resin and before the step of curing the UV curable resin.
11. The method for producing an optical disc according to wherein said step of curing the UV curable resin includes a first sub-step of running the substrate in rotation and illuminating UV rays on only the UV curable resin coated on the signal recording area of the recording layer;
claim 6
a second sub-step of running the substrate in rotation at an rpm larger than the rpm at which the substrate is run in rotation at said first step, for removing part of the UV curable resin on an area other than said signal recording area on an outer rim portion of the substrate; and
a third sub-step, subsequent to said second step, of running the substrate in rotation at an rpm lower than the rpm with which the substrate is run in rotation in said second step and concomitantly illuminating UV rays at least on an area other than the signal recording area for curing the UV curable resin.
12. The method for producing an optical disc according to wherein said step of coating the UV curable resin is carried out after illuminating UV rays on the area of said substrate other than the signal recording area.
claim 6
13. The method for producing an optical disc according to wherein said step of coating the UV curable resin includes a first sub-step of fitting said substrate inside of an annular auxiliary substrate having an inner diameter substantially equal to the outer diameter of an optical disc to be formed for supporting said substrate and a second sub-step of dripping a UV curable resin onto said auxiliary substrate and said substrate to get the UV curable resin stretched on rotation by rotation of said auxiliary substrate and said substrate;
claim 6
there being a further step subsequent to the UV curable resin curing step for dismounting said auxiliary plate and for removing the UV curable resin on said auxiliary substrate.
14. The method for producing an optical disc according to wherein, following the step of coating the UV curable resin and the step of curing the UV curable resin, with the use of a substrate having an outer diameter larger than a desired value, part of the substrate is removed to give a desired outer diameter 15.
claim 6
15. The method for producing an optical disc according to wherein, following the step of coating the UV curable resin, part of the UV curable resin coated on the outermost rim of the substrate is absorbed by a resin-absorbing material.
claim 6
16. The method for producing an optical disc according to wherein, following the step of coating the UV curable resin, part of the UV curable resin coated on the outermost rim of the substrate is sucked by suction means.
claim 6
17. The method for producing an optical disc according to wherein, following the step of coating the UV curable resin, part of the UV curable resin coated on the outermost rim of the substrate is blown off by a gas injection means.
claim 6
18. The method for producing an optical disc according to wherein said UV curable resin has a viscosity not less than 4000 cps.
claim 6
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/552,220 US6613396B1 (en) | 1998-01-09 | 2000-04-19 | Optical disc and method for manufacturing same |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JPP10-003485 | 1998-01-09 | ||
JP10003485A JPH11203724A (en) | 1998-01-09 | 1998-01-09 | Optical disk and its production |
JP10-003485 | 1998-01-09 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/552,220 Division US6613396B1 (en) | 1998-01-09 | 2000-04-19 | Optical disc and method for manufacturing same |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010046203A1 true US20010046203A1 (en) | 2001-11-29 |
US6349086B2 US6349086B2 (en) | 2002-02-19 |
Family
ID=11558650
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/226,701 Expired - Lifetime US6349086B2 (en) | 1998-01-09 | 1999-01-07 | Optical disc and method for manufacturing same |
US09/552,220 Expired - Lifetime US6613396B1 (en) | 1998-01-09 | 2000-04-19 | Optical disc and method for manufacturing same |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/552,220 Expired - Lifetime US6613396B1 (en) | 1998-01-09 | 2000-04-19 | Optical disc and method for manufacturing same |
Country Status (2)
Country | Link |
---|---|
US (2) | US6349086B2 (en) |
JP (1) | JPH11203724A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7041333B2 (en) | 2001-07-05 | 2006-05-09 | Samsung Electronics Co., Ltd. | Method of and apparatus for manufacturing optical disc |
US20070020561A1 (en) * | 2005-07-21 | 2007-01-25 | Kazuya Hisada | Manufacturing method and manufacturing apparatus for an optical data recording medium, and an optical data recording medium |
US20160250838A1 (en) * | 2006-05-30 | 2016-09-01 | Mitsubishi Heavy Industries Machine Tool Co., Ltd. | Device manufactured by room-temperature bonding, device manufacturing method, and room-temperature bonding apparatus |
Families Citing this family (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1203482C (en) * | 2000-02-25 | 2005-05-25 | 皇家菲利浦电子有限公司 | Circular optical storage disc and method for producing it |
ATE354166T1 (en) * | 2000-04-25 | 2007-03-15 | Matsushita Electric Ind Co Ltd | METHOD FOR PRODUCING A DISK SUBSTRATE AND METHOD AND APPARATUS FOR PRODUCING AN OPTICAL DISC |
JP2002063737A (en) * | 2000-06-09 | 2002-02-28 | Tdk Corp | Optical information medium and method of manufacturing the same |
EP1363280A4 (en) | 2001-02-23 | 2007-05-30 | Tdk Corp | Optical information medium manufacturing method and optical information medium |
TW584848B (en) | 2001-03-30 | 2004-04-21 | Tdk Corp | Moulding die, metallic mould system, recording medium base plate, recording medium, optical disc base plate, optical disc, moulding die making method |
DE60217116T2 (en) * | 2001-06-06 | 2007-08-09 | Matsushita Electric Industrial Co., Ltd., Kadoma | MANUFACTURING METHOD AND MANUFACTURING DEVICE FOR AN OPTICAL INFORMATION RECORDING MEDIUM |
US20040184397A1 (en) * | 2001-07-27 | 2004-09-23 | Kazuta Saito | Optical recording medium, method of producing the same and protective film-forming resin |
JPWO2003017267A1 (en) | 2001-08-21 | 2004-12-09 | Tdk株式会社 | Optical recording medium |
JP3833506B2 (en) | 2001-08-28 | 2006-10-11 | Tdk株式会社 | Stamper for manufacturing optical recording medium, method for forming information recording area and light transmission layer, and optical recording medium |
JP2003203401A (en) * | 2001-12-28 | 2003-07-18 | Matsushita Electric Ind Co Ltd | Coating method and method of forming resin layer |
KR100878519B1 (en) * | 2002-01-19 | 2009-01-13 | 삼성전자주식회사 | Manufacturing method for optical disk |
JP2003233936A (en) * | 2002-02-07 | 2003-08-22 | Pioneer Electronic Corp | Method of manufacturing optical disk and apparatus for manufacturing the same |
JP2003272237A (en) * | 2002-03-20 | 2003-09-26 | Sony Corp | Optical recording medium and manufacturing method thereof |
MXPA03005877A (en) | 2002-07-04 | 2006-04-24 | Matsushita Electric Ind Co Ltd | Optical data recording medium and manufacturing method for the same. |
JP4221455B2 (en) * | 2002-10-23 | 2009-02-12 | 三星電子株式会社 | Pattern forming material and pattern forming method |
TWI294125B (en) * | 2003-06-24 | 2008-03-01 | Ind Tech Res Inst | Manufacturing method of cover layer of optical information storage media |
JP2005038491A (en) * | 2003-07-18 | 2005-02-10 | Idemitsu Technofine Co Ltd | Manufacturing method of information recording medium, and information recording medium |
US6866887B1 (en) * | 2003-10-14 | 2005-03-15 | Photon Dynamics, Inc. | Method for manufacturing PDLC-based electro-optic modulator using spin coating |
KR100831109B1 (en) * | 2004-04-08 | 2008-05-20 | 포톤 다이나믹스, 인코포레이티드 | Polymer dispersed liquid crystal formulations for modulator fabrication |
TWI307505B (en) * | 2006-03-08 | 2009-03-11 | Ind Tech Res Inst | Apparatus for fabricating coverlayer of optical information storage media and operating method of the same |
JP4715657B2 (en) * | 2006-07-07 | 2011-07-06 | ソニー株式会社 | Optical disk medium and optical disk medium manufacturing method |
MX2009006182A (en) * | 2007-02-02 | 2009-06-26 | Tokuyama Corp | Method for manufacturing lens having coated layer. |
US8801964B2 (en) | 2010-12-22 | 2014-08-12 | Photon Dynamics, Inc. | Encapsulated polymer network liquid crystal material, device and applications |
Family Cites Families (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60256946A (en) * | 1984-06-01 | 1985-12-18 | Matsushita Electric Ind Co Ltd | Formation of cured protective film for disc |
JPS6288156A (en) * | 1985-10-14 | 1987-04-22 | Mitsubishi Chem Ind Ltd | Optical disk substrate |
JPS62155965A (en) * | 1985-12-27 | 1987-07-10 | Sony Corp | Spin coater for ultraviolet-curing type resin |
JPS6310348A (en) * | 1986-06-30 | 1988-01-16 | Konica Corp | Production of optical disk |
JPH01248339A (en) * | 1988-03-28 | 1989-10-03 | Canon Inc | Production of substrate for optical recording medium |
JPH01181129U (en) * | 1988-06-10 | 1989-12-27 | ||
JPH02167789A (en) * | 1988-12-22 | 1990-06-28 | Toshiba Corp | Information recording medium |
JPH02223480A (en) * | 1989-02-27 | 1990-09-05 | Hitachi Maxell Ltd | Optical information recording medium and production thereof |
US5188863A (en) * | 1989-06-30 | 1993-02-23 | E. I. Du Pont De Nemours And Company | Direct effect master/stamper for optical recording |
US5202863A (en) * | 1990-09-11 | 1993-04-13 | Matsushita Electric Industrial Co., Ltd. | Magneto-optical disk unit compatible with different two types of magneto-optical disks and a magnetic-field generator suitable thereof |
JP2774877B2 (en) * | 1991-03-19 | 1998-07-09 | 富士通株式会社 | Optical disc manufacturing method |
JP2633106B2 (en) * | 1991-05-24 | 1997-07-23 | シャープ株式会社 | Resist coating equipment |
JPH0547050A (en) * | 1991-08-09 | 1993-02-26 | Dainippon Ink & Chem Inc | Method for applying hard coating material or protective coating material of optical disk |
JP3104092B2 (en) * | 1991-11-30 | 2000-10-30 | ソニー株式会社 | Optical disc manufacturing method |
JP3208583B2 (en) * | 1991-11-30 | 2001-09-17 | ソニー株式会社 | optical disk |
US5312663A (en) * | 1991-12-27 | 1994-05-17 | Eastman Kodak Company | Optical element having durability enhancing layer |
JP3407316B2 (en) * | 1991-12-28 | 2003-05-19 | ソニー株式会社 | Magneto-optical disk |
JPH05266513A (en) * | 1992-03-19 | 1993-10-15 | Ricoh Co Ltd | Optical disk and its production |
JPH05325287A (en) * | 1992-05-15 | 1993-12-10 | Sony Corp | Optical disk medium and its production and optical disk system |
JP3443867B2 (en) * | 1992-06-26 | 2003-09-08 | ソニー株式会社 | Image signal encoding / decoding method and image signal recording medium |
JP3277951B2 (en) * | 1992-09-18 | 2002-04-22 | ソニー株式会社 | Method of forming protective film for optical disk |
JPH06150402A (en) * | 1992-10-30 | 1994-05-31 | Sony Corp | Production of optical disk |
JPH06302020A (en) * | 1993-04-15 | 1994-10-28 | Dainippon Ink & Chem Inc | Rotary coating method and rotary coater |
JPH0757297A (en) * | 1993-08-13 | 1995-03-03 | Sony Corp | Optical disk |
JPH0863815A (en) * | 1994-08-18 | 1996-03-08 | Sony Corp | Production of magnetooptical disc |
JPH0877629A (en) * | 1994-08-31 | 1996-03-22 | Sony Corp | Optical disc and its manufacture |
US5714222A (en) * | 1995-01-23 | 1998-02-03 | Canon Kabushiki Kaisha | Optical recording medium and process for producing same |
US5681634A (en) * | 1995-02-15 | 1997-10-28 | Matsushita Electric Industrial Co., Ltd. | Optical information medium, and method and apparatus for fabricating the same |
JPH0997452A (en) * | 1995-09-29 | 1997-04-08 | Sony Corp | Production of multilayered optical recording medium |
JP3449848B2 (en) * | 1995-12-11 | 2003-09-22 | 株式会社ソニー・ディスクテクノロジー | Apparatus and method for forming light transmitting layer in optical disc |
JPH09167382A (en) * | 1995-12-14 | 1997-06-24 | Tosoh Corp | Laminated disk and its manufacture |
US6495205B1 (en) * | 1998-02-17 | 2002-12-17 | Fastar, Ltd. | Linear extrusion coating system and method |
-
1998
- 1998-01-09 JP JP10003485A patent/JPH11203724A/en not_active Abandoned
-
1999
- 1999-01-07 US US09/226,701 patent/US6349086B2/en not_active Expired - Lifetime
-
2000
- 2000-04-19 US US09/552,220 patent/US6613396B1/en not_active Expired - Lifetime
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7041333B2 (en) | 2001-07-05 | 2006-05-09 | Samsung Electronics Co., Ltd. | Method of and apparatus for manufacturing optical disc |
US20070020561A1 (en) * | 2005-07-21 | 2007-01-25 | Kazuya Hisada | Manufacturing method and manufacturing apparatus for an optical data recording medium, and an optical data recording medium |
WO2007011042A2 (en) * | 2005-07-21 | 2007-01-25 | Matsushita Electric Industrial Co., Ltd. | Manufacturing method and manufacturing apparatus for an optical data recording medium, and an optical data recording medium |
WO2007011042A3 (en) * | 2005-07-21 | 2007-05-18 | Matsushita Electric Ind Co Ltd | Manufacturing method and manufacturing apparatus for an optical data recording medium, and an optical data recording medium |
US20160250838A1 (en) * | 2006-05-30 | 2016-09-01 | Mitsubishi Heavy Industries Machine Tool Co., Ltd. | Device manufactured by room-temperature bonding, device manufacturing method, and room-temperature bonding apparatus |
US10112376B2 (en) * | 2006-05-30 | 2018-10-30 | Mitsubishi Heavy Industries Machine Tool, Co., Ltd. | Device manufactured by room-temperature bonding, device manufacturing method, and room-temperature bonding apparatus |
Also Published As
Publication number | Publication date |
---|---|
US6349086B2 (en) | 2002-02-19 |
JPH11203724A (en) | 1999-07-30 |
US6613396B1 (en) | 2003-09-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6613396B1 (en) | Optical disc and method for manufacturing same | |
US4778747A (en) | Method of manufacturing optical memory element | |
US6077349A (en) | Method and apparatus for manufacturing disc-shaped recording medium | |
US5980985A (en) | Method and apparatus for forming protective film | |
JPH1173691A (en) | Production of optical disk and optical disk produced by that method | |
JPH0358333A (en) | Optical information recording medium | |
JP2000280255A (en) | Production of master disk | |
JP3557863B2 (en) | Protective film forming apparatus and protective film forming method | |
JP3986875B2 (en) | Optical disc and manufacturing method thereof | |
JPH0685237B2 (en) | Method of manufacturing magneto-optical memory device | |
JP4284888B2 (en) | Optical information recording medium | |
JP2001023243A (en) | Information recording carrier and information recording carrier reproducing device | |
JP2665281B2 (en) | Method for manufacturing optical memory device | |
JPH09134547A (en) | Optical recording medium and its manufacture | |
EP1756821A1 (en) | Apparatus for optical disc spin-coating | |
KR20050120206A (en) | Apparatus for attaching and detaching cap for optical disc spin-coating, apparatus for optical disc spin-coating using the same and method for preparing an optical disc using the same | |
JPH05159394A (en) | Production of optical disk | |
WO2001027919A1 (en) | Magnetooptic recording medium and magnetooptic recorder | |
JPH05325287A (en) | Optical disk medium and its production and optical disk system | |
JPH0855370A (en) | Production of optical disk and stamper, metal mold, and optical disk | |
KR100922428B1 (en) | Apparatus for attaching and detaching cap for optical disc spin-coating, apparatus for optical disc spin-coating using the same and method for preparing an optical disc using the same | |
JPH0585972B2 (en) | ||
JP2002163842A (en) | Optical recording medium of surface-reproduction type | |
JP2002150610A (en) | Information recording carrier and its manufacturing method | |
JP2003272241A (en) | Optical recording medium and drive unit thereof |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SONY CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NISHIDA, MASATO;SAKAMOTO, TETSUHIRO;KASHIWAGI, TOSHIYUKI;AND OTHERS;REEL/FRAME:009836/0001;SIGNING DATES FROM 19990304 TO 19990305 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FEPP | Fee payment procedure |
Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
FPAY | Fee payment |
Year of fee payment: 12 |