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
  • G11B7/26—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
  • G11B7/24097—Structures for detection, control, recording operation or replay operation; Special shapes or structures for centering or eccentricity prevention; Arrangements for testing, inspecting or evaluating; Containers, cartridges or cassettes
• • 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
• • 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
  • B29L2017/00—Carriers for sound or information
  • B29L2017/001—Carriers of records containing fine grooves or impressions, e.g. disc records for needle playback, cylinder records
  • B29L2017/003—Records or discs
  • B29L2017/005—CD''s, DVD''s

Definitions

• the invention relates to a method for the manufacture of information carriers such as CDs and DVDs.
• CDs and DVDs usually comprise a circular, translucent plastic disc of standardized cross section, on which a finish layer is provided using sputtering technique.
• the finish layer provides for reflection of light such as laser light for playback of information from and/or providing information on the information carrier.
• This is done in an apparatus in which first a disc-shaped carrier is manufactured, which is subsequently displaced, for instance with a carrousel, to a sputtering chamber in the same apparatus.
• Such apparatuses are relatively slow and moreover the disc-shaped carriers are to be made of relatively thick design in order to obtain the desired thickness of the information carrier.
• the information carrier should be made of particularly flat design, with sufficient stiffness to be able to resist very high rotation speeds when played. It has been found that the known method leads to undesired stresses in the information carriers and surface irregularities, which adversely affect the information density that can be achieved on such an information carrier.
• the object of the invention is to provide an alternative method for the manufacture of information carriers.
• the object of the invention is to provide such a method with which at least one or more of the disadvantages of the known method can be obviated.
• a method according to the invention is characterized in that disc- shaped carriers are manufactured in an apparatus physically separate from the apparatus for providing the or each finish layer.
• the disc-shaped carriers are manufactured in a forming apparatus, after which the carriers are packaged under conditioned conditions, in particular substantially dust-free.
• the package with the or each carrier is then passed to a processing apparatus for providing a finish layer such as the above-mentioned mirroring, light -reflective layer.
• a light-sensitive layer can be provided, for instance for manufacturing writable information carriers.
• An advantage of such a method is that the manufacture of the disc- shaped carriers is physically separated from the provision of the finish layer or layers, so that for each of these processes optimum conditions can be created, for instance in cycle time and numbers of forming apparatuses, or mold cavities, in such an apparatus, and processing apparatuses, or processing stations, included therein.
• a further advantage is that the forming apparatus and the processing apparatus can be set up in differently conditioned spaces, which limits the size of such spaces considerably compared with the known apparatuses which are to be included in their entirety in a clean room.
• a further advantage of a method according to the invention is that for different processing methods, at least finish layers to be provided, the same disc-shaped carriers can be manufactured, in the same forming apparatus, which means that considerable scale advantages can be achieved. In this way, the production costs can be reduced still further.
• Such a method provides the advantage that particularly short cycle times can be achieved, with minimal stresses or even without any stresses in the disc-shaped carriers.
• the carriers can be made of particularly thin design, without surface deformations, without internal stresses and irregularities, and being completely flat. Completely flat should herein be understood to mean at least as acceptable within the tolerances within the industrial standard for the respective information carriers.
• a method and molds for such a forming apparatus are for instance described more in particular in the international patent application WO 2004/024416, which application is incorporated herein by reference, at least in respect of the methods and the molds as forming apparatuses described therein.
• disc-shaped carriers can be used which are considerably thinner than is conventional. Thus, for instance, they can constitute less than half of the thickness of the total information carrier, or even less than a quarter, without this leading to problems when playing it.
• the starting point has been the normal thickness of such information carriers, according to the respective industrial standard.
• the thickness of the carrier can for instance be less than 0.6 mm, in particular less than approximately 0.4 mm and more particularly between approximately 0.2 and 0.4 mm.
• a relatively inexpensive covering can be provided, for instance a second plastic disc, for obtaining the desired thickness of the information carrier. This covering can for instance be glued on the finish layer, but can also be provided, for instance, by injection molding or with the technique described above.
• a lacquer layer can be provided as a protection.
• the slight thickness of the carrier moreover provides the advantage that it transmits light still better, with less fracture or diffusion.
• the invention furthermore relates to an assembly for the formation of information carriers, characterized by the features according to claim 14. With such an assembly, in a particularly advantageous and economic 21
• a package in which a stack of disc-shaped carriers can be packaged which package can be used for input of the carriers into the processing apparatus.
• a tubular, dust-free package which is placed on an input side of a processing apparatus and from which the carriers are taken out for instance one by one or in pairs and laid in a processing station such as a sputtering chamber.
• a processing station such as a sputtering chamber.
• use can be made of, for instance, a robot or gravity.
• the processing apparatus can be simply dust-tight, at least protected from external influences, so that only the coupling between the package and the processing apparatus needs to be dust-tight. As a consequence, the processing apparatus does not necessarily need to be set up in a clean room.
• the packages can be both single -use packages and returnable packages.
• a forming apparatus for use in an assembly according to the invention is preferably provided with a mold having one or more mold cavities, provided with a movable wall part and means for moving that wall part so fast as to give rise to adiabatic heat development in plastic in the respective mold cavity.
• a carrier can be manufactured, virtually without internal stresses, of a slight thickness, suitable as a basis for an information carrier according to the invention.
• the assembly is arranged for placing behind the finish layer a covering, in particular a further plastic disc, for instance from a cheaper and/or lesser- or non-translucent material such as PP of PS, so that a still less costly information carrier is obtained.
• a multiple mold is provided, for forming a plurality of carriers simultaneously in a cycle.
• the processing apparatus can for instance comprise a sputtering device or molds but can also be designed as a label device.
• the invention furthermore relates to an information carrier, characterized by the features according to claim 21.
• an information carrier provides the advantage that it can be manufactured particularly simply and relatively cheaply.
• such an information carrier is characterized by the features according to claim 22.
• Such an information carrier is cheap and can be provided with a particularly high information density. Nonetheless, the information carrier can have standard dimensions and be sufficiently stiff, homogeneous and stress-free to tolerate the rotary speed when played.
• the invention also relates in particular to an information carrier such as a CD or DVD, where a translucent plastic carrier is provided with a thickness of less than approximately 1.2 mm, more in particular less than approximately 0.6 mm on a side of the information carrier to be read out.
• a carrier of an information carrier can for instance be approximately 0.4 mm or less.
• less relatively costly material can suffice or such a carrier may even be manufactured from for instance PS or PET, without readability being thereby adversely affected.
• FIG. IA-C schematically show in sectional side elevation an advantageous embodiment of an apparatus for manufacturing carriers for use with the invention
• Fig. 2 schematically shows an assembly for manufacturing information carriers such as CDs or DVDs
• Fig. 3 schematically shows in sectional side elevation a package for use in an assembly or method according to the invention.
• Figs. 4A-C shows in side elevation three information carriers according to the invention.
• Fig. 1 shows in sectional side elevation an apparatus 1 for manufacturing carriers 100 according to the invention, provided with a mold 2 having therein a mold cavity 3.
• an apparatus 1 is used that is designed as a multiple mold, which means that more than one mold cavity 3 is provided, preferably equal mold cavities. These can be supplied from a same plasticizing unit 15 or from different such units 15.
• An apparatus 1 as described here is further elaborated both in structure and in use in the International patent application WO 2004/024416, which is incorporated herein by reference.
• the mold 2 comprises a first, movable part 4 and a second, complementary and fixedly set-up part 5.
• the movable part 4 is guided by suitable guides, which are not shown but can be, for instance, sliding pins, rails, guide rods of a press of the like and are readily apparent to one skilled in the art.
• the movable part is movable with the aid of devices suitable therefor, represented in Fig. 1 as piston-cylinder assemblies 7. It is clear that this can be any suitable device, for instance also a simple press, screw means such as spindles, linkages and the like. These can be made of relatively light design, since they are only intended for moving the part 5, and basically not for taking up any tensile or pressure forces in the further cycle.
• a slide 8 movable in the direction S between a retracted position shown in Figs. IA and B, and an extended position shown in Fig. 1C.
• two wedge-shaped elements to be called wedges 9 are provided, which are movable in a direction P with the aid of piston-cylinder assemblies 10 which are, for instance, hydraulically driven from a central control unit 11.
• the wedges 9 move in the direction P approximately at right angles to the direction S.
• the slide 8 is provided with two surfaces 12 inclining in opposite directions, complementary to the top surfaces of the wedges 9, such that if the wedges 9 are moved inwards, towards each other, the slide 8 is moved upwards (directions viewed in the plane of the paper) towards the extended position and vice versa.
• the wedge angles are, for instance, between 1 and 10 degrees, more particularly approximately 4 degrees, and in any case have been chosen such as to enable a desired rapid movement of the slide 8, as will be further elucidated hereinafter.
• a circular inflow opening 14 terminates in the mold cavity 3 and is connected to an injection device 15, for instance a plasticizing unit and optionally a pressing means.
• flanges 16 may be provided which, using blocking means 17, can be pressed onto each other and so held, for keeping the mold closed.
• the blocking means comprise, in the exemplary embodiment shown, brackets 18 which are movable using piston-cylinder assemblies 19, and can be pressed over the flanges 16. In this way, the desired closing pressure can be simply obtained and maintained.
• a conventional pressing device can be used as well.
• a central opening 22 through which extends a central column 21 which is fixedly connected with the part 5 of the mold 2.
• This column can for instance form a fixed, integral part thereof.
• the opposite part 4 of the mold has a central elevation 24 through which extends the opening 14 which terminates in an annular outflow opening 14A or a number of circumferentially distributed outflow openings.
• the distance D between the top surface 20 of the slide 8, leading in the direction of movement, and the opposite surface 23 of the mold cavity, is set with slide 8 in retracted position, depending on the desired product wall thickness and the plastic to be used, with the distance being basically set greater according as the melt of the plastic is higher and/or the melting temperature of the plastic is lower.
• a carrier 30 in the form of a translucent plastic disc can be formed, for instance from Polycarbonate (PC), PS, in particular high impact PS or PET. From the position shown in Fig. IA, the mold 2 is closed, as shown in
• Fig. IB The distance D is then set at a suitable value, such that the space in the mold cavity 3 is relatively great.
• plastic is introduced into the mold cavity under relatively low pressure, for instance at a pressure of between 1 and 10 bars excess pressure.
• the filling pressure is selected such that a desired, short feed time is achieved without the material properties of the plastic being adversely affected and without undesirably high pressure occurring in the mold cavity.
• the slide 208 is moved forward, in the direction of the extended position, as shown in Fig. 1C, by moving the wedges 9.
• the speed is selected depending on the desired adiabatic heat development which should be such that the temperature of the plastic is at least substantially readjusted to approximately the melting temperature thereof.
• any slightly solidified plastic reliquefi.es and can be forced further into the mold so that a complete filling of the mold cavity is obtained while the product can have wall thicknesses which are actually too small for the melt flow index of the respective plastic/product combination.
• some hold pressure can be applied with the aid of the injection device 15, so that undesired stresses can be pressed from the product.
• injection molding can be stressless.
• the mold can be opened again and the product can be taken out.
• the rate of movement of the or each slide is preferably so high that the time of movement of the slide between the retracted and the extended position is relatively short with respect to the cycle time for the manufacture of a product, for instance between 0 and 10% of that time, also depending on the desired adiabatic heating.
• This can be experimentally determined for each plastic/product combination or be calculated with the aid of standard tables regarding plastics, the product properties such as dimensions and flow paths, the friction that will occur when moving the slide, and the heat capacity and melting temperature of the plastic.
• a carrier is manufactured from PC, having a thickness that is smaller than the conventional thickness.
• a thickness can be used of less than 1.2 mm, for instance a thickness of 0.6 mm or less. Thicknesses for such a carrier of, for instance, 0.4 mm or less are possible and advantageous.
• a carrier is used having a thickness of less than approximately 0.6 mm, for instance 0.5 mm or less.
• a carrier 30 according to the invention can also be made with a different production method, for instance conventional injection molding, injection compression molding or the like.
• Use of a type of apparatus described above, however, is advantageous because of, for instance, minimal stress, minimal deformation after demolding, slight required thickness, material saving, short cycle time, relatively low injection temperature and pressure and the like.
• FIG. 2 an assembly is shown for manufacturing information carriers such as CDs or DVDs.
• information carriers such as CDs or DVDs.
• Such information carriers meet world standards as employed by Philip s®/Sony® for, for instance, audio and video CDs, DVDs and like plate-shaped information carriers. Conventionally, these have a circular form with a central opening, but they may also be shaped differently. CDs and DVDs of any type can be manufactured with it.
• the assembly 100 comprises a forming apparatus 101, a packaging apparatus 102 and a processing apparatus 103. Furthermore, an apparatus 104 is provided, with which a covering can be provided, as will be described in more detail below. Packing means 105 as conventionally used may be provided for packing the information carriers in, for instance, transport and storage packages. Such an apparatus, being generally known, will not be further described here.
• the forming apparatus 101 comprises an apparatus 1 as described with reference to Fig. 1 and a transfer device, for instance a robot 106, and is closed off dust-tight in a space suitable therefor, for instance a room or cabinet 107 which the packaging apparatus 102 communicates with or is included in.
• a transfer device for instance a robot 106
• a space suitable therefor for instance a room or cabinet 107 which the packaging apparatus 102 communicates with or is included in.
• a transfer device for instance a robot 106
• Carriers 30 can be taken out of the mold 2 with the robot 106 and be placed on a spindle 108, so that a stack is formed thereon.
• a tube 110 is slipped over the spindle 108 and the carriers 30 placed thereon.
• the tube 110 has a closed first end 11 and at the opposite second end is connected dust-tightly to the spindle 108, at least a base 111 thereof.
• a processing apparatus 103 for instance a sputtering device or a device in which foil is processed.
• the spindle is placed in a dust -tight housing 112 and the tube 110 is removed, so that the carriers can be taken off the spindle 108, for instance with a robot, and can be laid in the processing apparatus 103, for instance a traditional sputtering station.
• a finish layer is provided on a side of the carrier, for instance a light-sensitive layer and/or a mirroring layer and/or a lacquer layer or combinations thereof, depending on the type of CD or DVD being manufactured.
• finish layers are readily apparent to one skilled in the art and are not further elucidated here.
• the carrier with the finish layer which is either a complete information carrier or an intermediate product, is taken from the processing apparatus and packed in, for instance, a package 109 as described earlier, a box or other suitable type of package.
• post-operations may follow, such as the provision of a print, lacquer layer, label or the like.
• a covering layer 32 may be provided, for instance a plastic disc which may or may not be of translucent design.
• a covering layer 31 may be designed in transparent or non-translucent PE or PS, PET or ABS.
• High Impact PS is particularly suitable for this because of the high strength and stiffness and the relatively low price in proportion to for instance PC.
• Fig. 4 three different information carriers 40 according to the invention are shown. Thicknesses are given in the direction D.
• Fig. 4A shows an information carrier 40 with a carrier 30 and a finish layer 31 which has been provided thereon by sputtering or possibly labeling.
• a lacquer layer (not shown) is provided for protection.
• This is for instance a CD recordable or rewriteable or a common CD.
• This has a total thickness of approximately 1.2 mm, which is virtually wholly determined by the carrier 30 which is preferably manufactured from PC.
• Fig. 4B shows an information carrier 40 with a carrier 30 and a finish layer 31.
• a covering layer 32 is provided in the form of a plastic disc which has an equal section to the carrier 30 and a same central opening, as in conventional CDs and DVDs, so that it can be played back in normal playback equipment.
• the covering layer, at least the disc 32 is for instance manufactured from PS, in particular HIPS, PET or PE and may be fixed on the finish layer, for instance through injection molding technique or, preferably, through gluing.
• the carrier 30 has for instance a thickness of 0.6 mm or less, more in particular 0.5 mm or less and may be for instance between 0.1 and 0.4 mm thick.
• the total thickness of the information carrier is then approximately 1.2 mm, the thickness of the covering layer 32 then depending on the thickness of the carrier 30.
• a DVD-type information carrier is shown, where two carriers 30, each with a finish layer 31, are placed, for instance glued, onto each other, so that a multilayer information carrier 40 is obtained.
• a covering layer 32 may be provided, for instance manufactured from PE, PS, HIPS or PET but also other materials are possible, even paper or cardboard.
• the thickness of the carriers 30 may be, for instance, less than 0.6 mm, more in particular 0.5 mm or less, and may be, for instance, between 0.1 and 0.4 mm.
• the total thickness of the information carrier is then approximately 1.2 mm, so, with the thickness of the covering layer 32 depending on the thickness of the carriers 30.
• the carrier can also be manufactured from other plastic than PC, for instance PS, in particular High Impact PS (HIPS) or PET, which makes the information carrier still cheaper.
• PS High Impact PS
• PET High Impact PS
• the information density can be considerably greater than is conventional in comparable information carriers manufactured in conventional manner.
• the invention is not limited in any way to the examples given in the drawing and description. Many variations thereon are possible within the framework of the invention outlined by the claims. Thus, other dimensions and materials can be used and other setups within an assembly. Different parts of an assembly according to the invention can be integrated, such as processing apparatus and packaging apparatus, possibly with the forming apparatus. Other dust-free packages or different ways of transferring the carriers can be used.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Manufacturing Optical Record Carriers (AREA)
• Optical Record Carriers And Manufacture Thereof (AREA)
• Packaging For Recording Disks (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34974988

Family Applications (1)

Country Status (5)

Citations (5)

• 2004
  • 2004-12-01 NL NL1027638A patent/NL1027638C2/nl not_active IP Right Cessation
• 2005
  • 2005-11-30 EP EP05813721A patent/EP1829036A1/en not_active Withdrawn
  • 2005-11-30 JP JP2007544290A patent/JP2008522344A/ja active Pending
  • 2005-11-30 WO PCT/NL2005/000821 patent/WO2006059901A1/en active Application Filing
  • 2005-12-01 TW TW094142276A patent/TW200634813A/zh unknown

Patent Citations (5)

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