Abstract: A method to produce a wear resistant foil, including providing a first foil including a first thermoplastic material, applying wear resistant particles on the first foil, applying a second foil including a second thermoplastic material on the first foil, and adhering the first foil and the second foil to each other to form a wear resistant foil.

Abstract: A fine concavo-convex structure product (10) is provided with an etching layer (11), and a resist layer (12) comprised of a heat-reactive resist material for dry etching provided on the etching layer (11), a concavo-convex structure associated with opening portions (12a) formed in the resist layer (12) is formed in the etching layer (11), a pattern pitch P of a fine pattern of the concavo-convex structure ranges from 1 nm to 10 ?m, a pattern depth H of the fine pattern ranges from 1 nm to 10 ?m, and a pattern cross-sectional shape of the fine pattern is a trapezoid, a triangle or a mixed shape thereof. The heat-reactive resist material for dry etching has, as a principal constituent element, at least one species selected from the group consisting of Cu, Nb, Sn, Mn, oxides thereof, nitrides thereof and NiBi.

Abstract: A method of forming a chemical mechanical polishing pad. The method includes polymerizing one or more polymer precursors and forming a chemical-mechanical planarization pad including a surface, forming grooves in the surface defining lands between the grooves, wherein the grooves have a first width, and shrinking the lands from a first land length (L1) at the surface to a second land length (L2) at the surface, wherein the second land length (L2) is less than the first land length (L1) and the grooves have a second width (W2) wherein (W1)?(X)(W2), wherein (X) has a value in the range of 0.01 to 0.75.

Abstract: The invention is directed to new nanoimprint resist and thin-film compositions for use in nanoimprinting lithography. The compositions permit economical high-throughput mass production, using nanoimprint processes, of patterns having sub-200 nm, and even sub-50 nm features.

Abstract: Multilayer structure comprising at least one couple (L1-L2) of adjacent layers (L1) and (L2), wherein: the layer (L1) comprises at least one polymer composition (C1) comprising: (i) at least one semi-aromatic polyamide, and (ii) at least one impact modifier (I1); the layer (L2) comprises at least one polymer composition (C2) comprising: (i) at least one un-functionalized polyolefin (PO2); (ii) at least one functionalized polyolefin (FPO2), the functionalized polyolefin comprising functional groups chosen from carboxylic groups, their esters, their anhydrides and their salts. Process for manufacturing such multilayer structure, which comprises co-extruding or co-blowmolding polymer compositions (C1) and (C2) so as to obtain one couple (L1-L2) of adjacent layers (L1) and (L2). Shaped article comprising such multilayer structure and process for manufacturing the shaped article.

Abstract: A BCA mark is applied prior to molding of optical recording media. A stamper including a BCA code is formed. The stamper including the BCA code is used in the molding of optical recording discs. This technique can be used in manufacturing of read-only type discs, recordable discs, rewritable discs, hybrid discs, discs readable from both disc sides, discs having multiple information layers, high-density discs, etc.

Abstract: An imprint embossing alignment system. In one embodiment, the system includes a die having a bottom surface, an embossing foil positioned above the bottom surface, and a mandrel, to receive the substrate, having a rod portion that extends through a central portion of the die. The system also includes a ball bushing positioned around the rod portion and a ring portion positioned between the ball bushing and the embossing foil to hold a precise alignment of a centerline of the rod portion and a centerline of the embossing foil.

Abstract: An apparatus for transferring a pattern of minute surface structures, using a pair of press members which are located opposingly for movements toward and away from each other. One press member is adapted to support thereon a mold having on a transfer surface a master pattern of minute structures to be transferred, while the other press member is adapted to support thereon an annular substrate plate having a curable resin layer coated thereon and to press the resin layer against the transfer surface of the mold to transfer said minute structures to the resin layer. The mold is provided with a circular center hole defining at least three small-diameter segments and three large-diameter segments alternately and at uniform angular intervals along an inner periphery of the mold. The annular substrate plate has an inside diameter exactly matching with the small-diameter segments at the inner periphery of the mold.

Abstract: The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a method of fabricating a color filter for an LCD device. A method of fabricating a color filter uses a mold (PDMS mold) having a plurality of grooves. Particularly, the mold (PDMS mold) is attached to a substrate such that the plurality of grooves face into the substrate. When a color resin is dropped into a side opening of each groove, the color resin is injected into each groove of the mold (PDMS mold) by a capillary force. After the mold (PDMS mold) having the injected color resin is cured, the mold (PDMS mold) is detached from the substrate and a color filter pattern is formed at a desired position.

Abstract: A device (4) for transferring a pattern to an object (2). The invention relates especially to production of micro and nanostructures. The device comprises an alignment means (10) arranged in connection with a first contacting means (7) for controlling the motion of the first stamp (8) in a direction perpendicular to the pressing direction (A), and a second contacting means (11) having a second stamp (12) adapted to imprint a second pattern in the second surface (6) of the object (2), and a pressing means (9) further adapted to press the second stamp (12) into contact with the second surface (6) of the object (2) in the pressing direction (A). Hereby is obtained a device of a simple design, which has a high accuracy of the alignment of the stamps in relation to the object.

Abstract: An imprint embossing alignment system. In one embodiment, the system includes a die having a bottom surface, an embossing foil positioned above the bottom surface, and a mandrel, to receive the substrate, having a rod portion that extends through a central portion of the die. The system also includes a ball bushing positioned around the rod portion and a ring portion positioned between the ball bushing and the embossing foil to hold a precise alignment of a centerline of the rod portion and a centerline of the embossing foil.

Abstract: A method of aligning die and stamping substrate for nano-imprint lithography is described. The method includes aligning the die by linearly displacing the die along a first axis using a first flexure member and pressing the die along a second axis substantially perpendicular to the first axis while maintaining coupling of the die with the first flexure member.

Abstract: Binary information previously recorded in an innermost rim side area is enabled to be stably reproduced. A record medium is formed by sequentially laminating a first information layer 2, an intermediate layer 3, a second information layer 4, and a cover layer 5 onto a substrate 1. First grooves are previously formed in the innermost rim area of the substrate 1. Second grooves are previously formed in an area where data is recorded. The first grooves are set to be shallower and narrower than the second grooves. Thus, such a situation that a BCA signal is modulated by diffraction due to the grooves can be reduced.

Abstract: An optical disk is constructed such that a thin film including a reflective layer is formed on a substrate, or on a thermoplastic resin layer on the substrate. A stamper having an asperity pattern corresponding to information signals is directly pressed against the thin film to transfer the asperity pattern on the thin film. Heat-pressing the stamper against the thin film makes it possible to further accurately transfer the asperity of the stamper to the reflective layer with less pressing force, in the case where the reflective layer is formed on the thermoplastic resin layer.

Abstract: In an information storage device, a writing magnetic layer is formed on a substrate and has a magnetic domain wall. A connecting magnetic layer is formed on the writing magnetic layer, and an information storing magnetic layer is formed on an upper portion of side surfaces of the connecting magnetic layer. A reader reads information stored in the information storing magnetic layer.

Abstract: A die for molding a disk substrate capable of forming fine recessed and projected pits and grooves up to the outer periphery of the disk substrate by preventing low heat conductive elements from peeling off and burrs from occurring on the outer periphery thereof. The die includes a first base die, a second base die disposed oppositely to the first base die, a first low heat conductive element fixed to the first base die, a stamper fixed onto the first low heat conductive element, a second low heat conductive element fixed onto the second base die, and a ring-like regulating member fitted to and in slidable contact with either of the first and second low heat conductive elements. The die is characterized in that the end part of the ring-shaped regulating member is positioned within the range of the outer peripheral side face of the low heat conductive element in slidable contact therewith.

Abstract: An injection-moulding tool for the production of a mould in disc form, in particular in the form of information carriers such as CDs and/or DVDs, wherein the injection-moulding tool comprises a first and a second mirror block, wherein the first and second mirror blocks lie opposite each other and are movable in relation to each other for the opening and closing of the mould, and means for actively controlling the temperature of at least one of the first and second mirror blocks. A method for producing mouldings in disc form utilizing the injection-moulding tool is also disclosed.

Abstract: A method of forming a discrete track recording pattern on a soft magnetic underlayer of a perpendicular magnetic recording disk. In one embodiment, the soft magnetic underlayer is continuous throughout the discrete track recording pattern.

Abstract: A stamper/imprinter for use in performing thermal imprint lithography of a substrate/workpiece surface to form a pattern of features in first portions of the surface intended to receive the pattern, without incurring random formation of undesired, disordered features in second portions of the substrate/workpiece surface not intended to receive the pattern, comprising an imprinting surface configured to substantially prevent formation of gaps between the imprinting surface and the second portions of the surface during stamping/imprinting. Embodiments include stampers/imprinters with a multilevel imprinting surface comprises a first portion having a first level for forming the pattern of features in the first portions of the surface and a second portion having a second level for substantially preventing formation of gaps between the imprinting surface and the second portions of the surface during stamping/imprinting.

Abstract: A stamper-forming electrode material contains Cu as its main ingredient and at least one other element, preferably Ag and/or Ti. It is preferred that the Ag content be 10.0 wt % or less and that the Ti content be 5.0 wt % or less. A stamper-forming thin film is made of this stamper-forming electrode material, whereby its corrosion resistance is improved to suppress damage to itself, and a high-quality stamper can hence be formed.

Abstract: A method of manufacturing a magnetic stamper/imprinter for use in patterning of magnetic recording media by means of a contact printing process, comprising sequential steps of: (a) providing a stamper/imprinter comprising a body of a magnetic material having an imprinting surface including a topographical pattern corresponding to a pattern to be formed in the surface of a magnetic or magneto-optical (MO) recording medium and comprising a patterned plurality of spaced-apart recesses with a plurality of non-recessed areas therebetween, said imprinting surface including a plurality of defects comprising surface blemishes and stains, magnetic particles, and non-magnetic particles; (b) initially removing the surface blemishes, stains, and magnetic particles; and (c) then removing or rendering the non-magnetic particles benign to the contact printing process.

Abstract: A recording medium for information signals including a substrate, a signal recording layer provided on one major surface of the substrate and a clamp member having a positioning unit at its center portion and formed of a material that can be magnetically attracted by a magnet. The clamp member is unified to the center portion of the substrate so that the surface of the clamp member will be flush with the substrate surface.

Abstract: A film layer separation device for multilayer disks is disclosed. With the help of a stamper made of magnetic materials, the film layer separation is achieved through the attractive force imposed on the stamper by electromagnetic tearing. The device contains at least: a stamper supporter for supporting the stamper, an electromagnetic attraction device, and a base fixture. To distribute the electromagnetic force on the stamper evenly, the electromagnetic attraction device can have an array of homogeneously disposed electromagnetic iron cores and a conductive coil that can generate a magnetic force. Thus, there will be no localized stress when tearing.

Abstract: A method and apparatus for making multiple layer optical discs is applied to separate the base plate from the mold plate. The base plate is formed with a first opening, an empty zone and a data zone having a first recording layer. The apparatus includes a first adhesive ending groove, a mold plate, a sealing member and an air-blowing axle. The first adhesive-ending groove is formed on the empty zone of the base plate. The mold plate, movably pressed on the base plate, includes a main body, a second opening, a second adhesive ending groove, a second recording layer and an adhesive layer. The second opening is located on the main body at a position corresponding to the first opening of the base plate. The second adhesive-ending groove is located on the main body at a position corresponding to the first adhesive-ending groove of the base plate.

Abstract: There is disclosed a molding die which can prevent or restrain a wedge-like deformation from being formed at an outer peripheral portion of an optical recording disk. The molding die is for molding a thin circular plate optical recording disk by injecting a molten thermosetting resin in a cavity, and an outer peripheral member coming in contact with a portion which becomes an outer peripheral surface of the optical recording disk is made of a material having a thermal conductivity lower than a thermal conductivity of a material of an opposite member coming in contact with a portion which becomes a main surface of the optical recording disk, that is, a stamper, a stationary mirror, and a movable mirror.

Abstract: A molding die apparatus and a method thereof are provided, which ensures for air and gas (or fluid) present in a resin filling space to be exhausted so as to be able to fill molten resin into the cavity smoothly and uniformly thereby enabling production of a high quality molded resin product suitable as an optical disc substrate or the like having optimum optical properties required therefor. The molding die apparatus for obtaining the molded product by injecting the molten resin into a cavity that is formed between dies includes a vacuum apparatus which is disposed in proximity to the cavity, the vacuum apparatus including a vacuum tank, an exhaustion channel and a vacuum valve which controls open and close of a channel between the vacuum tank and the exhaustion channel, and the cavity is exhausted efficiently and rapidly by the vacuum apparatus.

Abstract: Disclosed is a stamper assembly for forming an optical data storage disk in a disk molding process. The stamper assembly includes a block element having a first major surface, and a stamper member having a first major surface and an opposite, second major surface. The first major surface of the stamper member is adapted to contact a disk molding material for forming an optical data storage disk in a disk molding process. The stamper assembly further includes a medium for securing the stamper member to the block element, such that substantially the entire second major surface of the stamper member is affixed to the first major surface of the block element. This arrangement prevents relative movement between the stamper member and the block element. This substantially reduces stamper member wear and increases the useful production lifetime of the stamper assembly.

Abstract: In order to realize a compact construction of an apparatus for producing an optical recording medium while shortening the time required for transporting a mold, there is provided an apparatus for producing an optical recording medium by curing a curable resin (102b) between a substrate (101) and a mold (103), including: a mold fixing mechanism (2) for fixing the mold (103); a transporting mechanism (1) for transporting the substrate (101) to which the curable resin (102b) has been applied to a position where the mold (103) is fixed, and placing the substrate (101) on the mold (103) such that the surface of said substrate to which the curable resin (102b) has been applied faces the mold (103); a resin curing mechanism (3) for curing the curable resin (102b) which has been sandwiched between the mold (103) and the substrate (101) by the action of the transporting mechanism (1); and a separating mechanism (4) for separating the resin (102) that has been cured by said resin curing mechanism (3), together with the

Abstract: An injection moulding unit includes at least two injection moulds for manufacturing disc-like objects. The injection moulds each further include two mould parts which are mutually displaceable between a closed position in which they bound a mould cavity and an opened position in which the disc-like object can be removed. The mould cavity is connected to a pressure line for carrying heated plastic into the mould cavity. A punching means is provided for punching a central hole through the disc-like object. The punching means includes a cylindrical part forming a portion of one of the mould parts and has a leading peripheral edge. The respective pressure lines of the injection moulds are branches of a feed line and together therewith form part of a collective multiple hot runner. The outlet zone of each feed line is configured to couple to an infeed of an injection bush. An outfeed of the injection bush debouches directly into the mould cavity.

Abstract: A nozzle for processing of plastics by way of an injection molding machine comprising a basic body (1), a nozzle head (2) and a thermally conducting torpedo (3) which are heated directly or indirectly respectively by a heating device (8). The thermally conducting torpedo (3) is clamped between the basic body (1) and the nozzle head (2). The thermally conducting torpedo (3) is fixed to an adapter (20). The thermally conducting torpedo (3) is arranged such that plastic molding compound is guided to outlets (21.1, 21.2) which are at a distance to a nozzle axis (15). The plastic molding compound is ejected out of the nozzle in e.g. radial outward direction into forming cavities (23.1, 23.2) of an injection mold (17). The nozzle prevents losses of material due to sprue and bore, is simply producible and at the same time guarantees a good heat transmission into the thermally conducting torpedo (3).

Abstract: The stamper 16 is disposed opposing to the cavity 3 formed between the fixed mold 1 and the movable mold 2, as a holding means of the circumference of the stamper the flat type of holding means 17 is provided, and when using this molded product for molding a disk, the air for releasing the mold is blown out from a plurality of air passages into the cavity. The air from the outer circumference side of the disk is blown out from one of the air supply opening provided on at least one of the recessed portion 28 formed on the holding means 17 and the mirror plate 15 opposing to the recessed portion 28 simultaneously, before or after the operation time of opening the mold during the time of restoring stroke of the holding means from being pushed against the resilient means 32 through the gap 30 between the inside projection wall 27 of the holding means 17 and the stamper surface 16a.

Abstract: A dynamic mold seal for a mold having two relatively movable mold halves is provided. The dynamic mold seal is formed by a sealing ring mounted or secured to a first one of the mold halves. The sealing ring includes a rigid ring portion and a sealing portion including a flexible sealing member for preventing leakage of the pressurized molten material from the mold and thereby preventing the creation of flash about the molded article. The flexible sealing member is preferably formed by a reduced cross section portion of the sealing portion.

Abstract: A mold assembly for forming a replica disk in a disk molding process. The replica disk includes a formatted surface on both sides. The mold assembly includes a disk substrate cavity defined by a first block having a first major surface, a second block having a second major surface, and an outside edge. The first stamper has an outside edge. The first outer holder includes a first holder edge, the first holder edge extends over the outside edge of the first stamper, coupling the first stamper to the first major surface. A second stamper having an outside edge is coupled to the second major surface. A channel is provided in fluid communication with the disk substrate cavity for allowing disk molding material to enter the disk substrate cavity. Further, a stripper mechanism may be located at the outside edge, wherein the stripper mechanism is moveable relative to the first block and the second block.

Abstract: A disc substrate molding metal mold apparatus adapted for molding synthetic resin material to carry out molding of disc substrate of an information signal recording medium. This metal mold apparatus is adapted so that smoothing layers of metal are integrally formed on the molding plane surface sides of a first metal mold serving as the fixed side and a second metal mold serving as the movable side which are butted to each other to constitute a molding portion for molding disc substrate, and uneven patterns corresponding to information signals, etc. formed at the disc substrate are directly formed at the metallic layers, thus to carry out molding of disc substrate in which the surface is flattened with high accuracy, and uneven patterns of the metal mold side are transferred without allowing local undulations and/or projections occurring on the disc surface to take place.

Abstract: A disc is provided which includes a disc body of disc shape having a center hole. An information recording area is formed on one side surface of the disc body. The information recording area has information thereon read by reflection of laser light. The information recording area has an inner circumferential edge positioned adjacent to the center hole. The disc body has a radius ranging from 39 mm to 80 mm, the center hole has a radius ranging from 7.5 mm to 7.55 mm, and the inner circumferential edge of the information recording area being positioned to extend from a radius of 15 mm to 22 mm from the center of the disc body.

Abstract: Into the cavity formed by closing a stationary mold with a movable mold, material is filled through a gate portion of a female cutter. After the material is filled into the cavity, a male cutter is advanced at a high speed from a starting position S to a vicinity position P of the female cutter, at the position P the advance speed is changed to a low speed and the male cutter advances at the low speed to an advancing limit position E to carry out the gate cutting. Then, the filled material solidifies while being cooled.

Abstract: Artwork is imparted to plastic discs such as CDs, CD ROMs, and DVDs (digital video discs) by exposing a layer of photoresist material on a substrate to light from an original image of the artwork. The material of the photoresist layer is exposed to different depths by different intensity light from different image regions. Where the image is dark, the exposure is to relatively shallow, random depths. Where the image is light, the full thickness of the photoresist layer is exposed. Development of the photoresist layer removes the exposed photoresist material. The surface features of the developed photoresist layer and any uncovered substrate are transferred to a member used in forming a surface of the plastic disc, thereby visibly embossing the image in the disc.

Abstract: A prescribed molded substrate is molded out of a melted resin with a stamper having projections for forming pits with the shape of the projections preliminarily set to be greater than the shape of pits of the substrate to be molded. The relationship between the height H of the projections for forming the pits to the stamper and the depth d of the molded substrate is such that H/d=1.3 to 1.8.

Abstract: A valve gate injection nozzle includes a valve stem for guiding molten resin to a molding area. The valve stem includes an input area for receiving the molten resin, a central area following the input area for processing the molten resin and an output area following the central area for connection of the nozzle with the molding area. The central area includes a first zone for splitting the molten resin into a plurality of streams, a second zone for mixing and homogenizing the molten resin, and a third zone for combing the plurality of streams and forming recombined molten resin for subsequent direction in a homogenized state to the output area. The nozzle further includes a nozzle body portion for enclosing the valve stem, wherein the nozzle body portion preferably includes means for heating the resin. An injection molding system incorporating this nozzle as well as a method for homogenizing molten resin are also disclosed.

Abstract: An optical disc molding device has a pair of molds for injection molding a disc substrate within cavities, and a stamper supported within at least one cavity, for molding a data recording surface in such a manner that the inside diameter side of the stamper supporting surface of the cavity protrudes inwardly in the disc thickness direction from the data recording surface. The flatness of a laminated reference plane has thus been deteriorated by burrs occurring on a disc substrate.

Abstract: The invention covers an injection molding apparatus and injection molding process. The apparatus has at least a first and second injection molding machine adjacent one another, with each machine including upper and lower mold elements operative to form molded products; and robot adjacent said injection molding machines operative to remove and replace at least a portion of one of said mold elements from a first of said injection molding machines while the second of said injection molding machines continues to form molded products.

Abstract: A multi-layer optical recording medium manufacturing method and apparatus thereof forms a resin layer having a second recording layer on a first recording layer. The first recording layer includes a reflecting layer and a first recording layer sequentially formed on a transparent substrate. The multi-layer optical recording medium manufacturing apparatus includes an upper and a lower mold on which is respectively fixed the transparent substrate and a stamp such that they are facing each other. Communicating holes formed in the transparent substrate and the stamp are formed in center portions of each of the molds. A punch member capable of vertical movement is established in the communicating hole of the lower mold, and resin supply established in the communicating hole of the upper mold. The above apparatus has the advantage of improving productivity of the manufacture of a multi-layer optical recording medium.

Abstract: An optical disk metal mold apparatus includes a fixed cavity plate; a movable cavity plate facing the fixed cavity plate; a disk-shaped plate disposed on at least one of the fixed and movable cavity plates such that it is movable with respect thereto; a stamper plate concentrically supported on the at least one of the fixed and movable cavity plates by the disk-shaped plate such that it is movable with respect to the disk-shaped plate and the at least one of the fixed and movable cavity plates; wherein the stamper plate and the disk-shaped plate are each made of a material and further configured such that a difference between respective deformations of the disk-shaped plate and the stamper plate caused by expansion and contraction thereof due to temperature changes during a molding cycle is smaller than a difference between respective deformations of the stamper plate and the at least one of the fixed and movable cavity plates caused by expansion and contraction thereof due to temperature changes during a mol

Abstract: An optical disk molding apparatus is provided which includes a fixed side mold assembly and a movable side mold assembly. Each mold assembly has a mounting plate, a disk cavity plate, a temperature control liquid passage, and a temperature control liquid sealing device. The temperature control liquid sealing device is comprised of at least one annular aperture formed between the mounting plate and the disk cavity plate around the inner or the outer circumference of the temperature control liquid passage in each of the mold assemblies, a rigid ring fitted within the annular aperture such that there is only a minute clearance between the inner wall of the annular aperture and the rigid ring, and a heat resistant sealing filler charged between the inner wall of the annular aperture and the rigid ring.

Abstract: An apparatus for holding a stamper plate in a molding metal die is provided which comprises a cavity plate having a cavity center hole, a stamper plate press member having a flange portion larger than the stamper plate center hole, a vacuum evacuation device, a compressed air supply device, a first connecting device for connecting the cavity center hole to the vacuum evacuation device, and a second connecting device for connecting the cavity center hole to the compressed air supply device. The stamper plate is mounted by inserting the stamper plate press member within the cavity center hole and the stamper plate center hole, such that the flange portion is engaged on the upper surface of the stamper plate and a space is formed between the stamper plate press member and the cavity center hole. The vacuum evacuation device is then connected to the cavity center hole through the first connecting device, so that the stamper plate press member is sucked into the cavity center hole.

Abstract: A mold is for molding DVD discs to be joined together, back-to-back, to make a single disc. The mold includes a movable moldhalf and a stationary moldhalf. On one of the half-molds an inserting block extends a small distance into the mold cavity, so that the central part of the cavity is thinner than the outer part. The inner part and the outer part correspond approximately to the outer information band and the inner portion of the disc which is grasped. The mold is preferably used in a method using first a lower compression force during resin injection and then an increased force.

Abstract: An injection mold for molding discs is provided, wherein the injection mold comprises a base die, a board fitted inside the base die, a stamper in the form of a doughnut fitted to the front surface of the board, an outer ring fitted to the front end of the base die, and a sleeve having a flange fitted to the center of the board, the ring and/or the flange fixing the stamper to the board. The injection mold further comprises a thin disc thicker than the stamper interposed closely between the stamper and the board so as that the front surface of the thin disc contacts with the back surface of the stamper. According to the thus constructed injection mold of the present invention, it is possible to prevent dust or dirt from sticking when the stamper is replaced in the field, and to make it unnecessary to replace the mirror surface board, by mounting the combination of the stamper and thin disc on the mold.

Abstract: A novel and improved metal mold for molding a runnerless product can be provided. The metal mold according to the present invention comprises a stationary and a movable mold halves, one of which is provided at the center thereof with a recess and the other of which is provided with a compression core to be retractably received by said recess, said stationary and movable mold halves defining a cavity for the runnerless product, and further comprises a hot nozzle inserted into the recess or the compression core and having a tip projecting therefrom to allow resin to be left around the nozzle. In such a construction, a runner section and a gate are defined by said recess and the compression core so as that they are closable by the movement of said compression core, and thereby the center of the final product, e.g. a disc can certainly be finished without punching, cutting or the like.

Abstract: An optical disk records digital information in optically-reflective layers that each vary in thickness between constructive interference of a monochromatic light and destructive interference of the said monochromatic light. The difference in the intensity of a reflected light beam subjected to interferometric constructive and destructive interference is used to communicate digital data from the optically-reflective layers and a detector. The optical disk provides for multiple layers of digital information that are tuned for interferometric response at correspondingly different monochromatic wavelengths of light. Another embodiment of the present invention is a mass-production process for making such an interferometric optical disk. Another embodiment of the present invention is a variation that includes layers that are emitting or absorbing depending on dopants.

Abstract: A multilayer information disc formed by joining a plurality of disc units and a manufacturing method thereof are provided. The plurality of disc units contain information tracks which have the same spiral directions relative to an optical pickup device when the plurality of the disc units are joined. As a result, information recorded on all of the disc units can be reproduced by rotating the multilayer information disc in a single direction. Consequently, the structure and cost of the recording/reproducing apparatus which reproduces the information is reduced.