Abstract: A method of producing a plate-shaped body, particularly a video disc in which circumferential warp in the thicknesswise direction, thickness fluctuation and deflection of the signal track are minimized comprisingThe steps of pressing by a mold a thermoplastic resin which has been heated to a temperature above the softening point thereof, and cooling the thermoplastic resin to solidify the same. During the cooling, the pressure of the mold is decreased to a low level when the thermoplastic resin has been cooled down to a temperature around the softening point. The thermoplastic resin is allowed to be solidified without any substantial and local residual stress to ensure minimal circumferential warp, thickness fluctuation and deflection signal track.

Abstract: A method and device for manufacturing a record carrier is disclosed in which a liquid moulding resin is deposited in a cavity formed in the surface of a mould which also has at least one data track. Thereafter a flexible substrate, having a central projection, is deformed into a convex shape and is pressed against the moulding resin. As the projection on the substrate enters the mating cavity in the mold, the resin is squeezed out of the cavity and rolled out across the mould surface by the substrate which is flattened into a planar form during the pressing step. The moulding resin is then cured and the assembly of the substrate with attached, cured resin layer is removed from the mould.

Abstract: An improved method of reproducing a spiral groove pattern in the surface of a plastic disc wherein the intersections of the surface of a metal article generated during the replication process are filled in to form concave junctions.

Abstract: A two stage moulding procedure for the production of foil video discs. In a first pressing operation a satin finish consisting of a surface irregularity is applied to a surface of the foil, and then, in a second pressing operation, the foil is pressed between stamper plates to impart thereto, at one or both surfaces an impression of the information or data to be recorded. The satin finish may be formed by pressing the foil between stamper plates bearing the satin finish at their inwardly facing surfaces or alternatively between a pair of rollers bearing the satin finish at their surfaces.

Abstract: A preform molding apparatus includes a mold cup which has opposed top and bottom mold members and a carrier arm between the mold members. The top mold member has a concave mold recess in its bottom surface and a semi-cylindrical rim extending downwardly from the edge of the mold recess. The bottom mold member has a concave mold recess in its top surface and a mold material inlet opening into the bottom of the mold recess. The carrier arm has a semi-cylindrical opening therethrough at one edge thereof. Pneumatic cylinders have piston rods connected to the mold members and the carrier arm for moving the mold members toward and away from each other and the carrier arm transversely across and away from the mold members.

Abstract: A record having an information track cut into the surface and a visible pattern formed on surface "lands" bordering the track. The pattern is shallower than the track depth, typically 0.7 micron for a 25 micron sound microgroove record track. A method of providing the marking by applying solvent to a lacquer before cutting a master is described.

Abstract: A conductive video disc replica is cleaned by washing with an aqueous solution comprising an oxidizing agent, a base and a surfactant of a fluorocarbon added in an amount so that the solution has a surface energy of about 35 dynes/cm.sup.2 or less. This solution removes metallic and oxygen-containing impurities from the surface of the disc and leaves a fluorinated surface.

Abstract: Methods and apparatus for making picture records whereby records of a high quality may be mass produced at a faster rate. In accordance with the method, a thin layer of plastic is first laminated over sheets containing the pictures desired. The laminated pictures are then cut from the sheets, preferably to have a diameter slightly smaller than the diameter of the desired finished record. Thereafter, the laminated pictures are placed in the record press two at a time, each with the picutre and plastic lamination thereover facing the adjacent die half. A biscuit, or alternatively a sheet of appropriate size is placed therebetween and the die is closed to press the record, with trimming, etc. proceeding in accordance with prior art techniques. Apparatus for practicing the method on an automatic record press is disclosed, though alternatively the method may be practiced to advantage on manual presses also.

Abstract: A recorded disk preproducing system in which a signal pattern recorded on a master disk is transferred to a reproducing disk positioned in close contact with the master disk upon exposure to flashing light. The master disk includes a thin film of a light screening material such as in organic compound, chalcogen compound, or the like formed on a transparent glass substrate, and an information signal is recorded on the thin film as a pattern of varied light transmission. The reproducing disk has a thin film of a heat sensitive material such as amorphous chalcogen compound formed on a transparent resin substrate, and the optical density and/or a light reflectance of the heat sensitive thin film is varied in accordance with the recorded signal pattern of the master disk upon exposure to the flashing light.

Abstract: An extruder control arrangement in which the time taken to deliver a known quantity of extrudate is maintained within closely controlled limits by feedback circuit which controls the rate at which plastics material is fed to the extruder.

Abstract: A process for making a plastic record including the ordered steps of placing a cake of transparent moldable plastic in a record press having grooves for impressing sound grooves into the plastic, placing on opaque sheet of material having a picture printed thereon on at least one side onto the cake in the record press, placing a transparent moldable plastic on top of the opaque sheet of material and pressing the combined cake, sheet and transparent plastic in the record press whereby a transparent record having a picture and sound grooves contained therein is formed.

Abstract: Method and apparatus for removing warps or surface irregularities from polyvinyl phonograph records by exerting forces vertically and/or laterially on a record. The apparatus includes a plurality of plate-like members which are used to engage with the lead-in lips and/or label regions on one or more records and to apply appropriate forces. The effectiveness of the method and apparatus is enhanced by the application of moderate heat from an external source.

Abstract: A picture phonograph record and method of making the same having an imprinted core sheet sandwiched between transparent layers one of which comprises a relatively thin preformed plastic foil and the other of which is a relatively rigid and thick layer dispersed radially over the core sheet from a hot fluent lump of plastic positioned between heated pressurized mold platens. Sound tracks are impressed onto the face of one or both plastic layers concurrently with the extrusion of the lump to form the thick plastic layer. At least the thicker and usually both layers become inseparably adherent to the adjacent face of the core sheet as an incident of the assembly and sound track impressing operation.

Abstract: The metallic surface of a master plate or mother plate is oxidized in a solution of hypochlorite to form a parting layer upon which a metal layer is plated. The metal layer may be stripped from the master plate or mother plate aided by the parting layer to form a matrix or stamper from which a plastic record disc, such as, a video disc, can be molded.

Abstract: A disc-shaped information carrier for high-density storage, in particular for video signals, has the information provided on both sides of the carrier and stored in the form of a beam-relfecting surface structure which is covered by a layer of translucent material. A disc-shaped base element is formed by injection molding, pressing, stamping or the like to exhibit a surface structure corresponding to the information to be stored on both sides thereof. Each side has a thin metallic coating applied thereto which maintains the same surface profile and the information structure is protected on each side with a layer of transparent material.

Abstract: A method of forming a recording disc having a smooth groove suitable for recording video information from a disc having irregularities along the peaks between adjacent groove convolutions by replicating the grooved disc to produce a negative reproduction of the groove and applying an excess of deformable or removable material such as electron beam sensitive material to the surface of the replicated disc while rotating the disc rapidly only long enough to drive off the excess material and allowing the remaining material to dry, partially filling the groove and providing a continuous coating over the wall and valley portions thereof.

Abstract: A method of recovering plastic material from phonograph record center sections and making plastic phonograph records incorporating the recovered material, comprising the steps of:A. recovering the plastic material from the center portions of discarded phonograph records by removing the labels from the center portions after they have been immersed in an aromatic hydrocarbon and crushing the center portions into small particles;B. combining the recovered material with proportions of scrap from phonograph records, briquets of plastic and new polyvinyl chloride to arrive at a new material composition comprising 20% recovered plastic from the center portions, 25% scrap plastic, 25% briquets, and 30% new polyvinyl chloride;C. heating the new material composition in a three temperature zoned furnace with its first zone being heated to a temperature ranging from 215.degree. F-225.degree. F, its second zone being heated to a temperature ranging from 235.degree. F-245.degree.

Abstract: A method of making disc records, particularly video discs from thermoplastic sheet material. In a press a thin flexible matrix is disposed between the sheet, which is backed by a resilient cushion, and a flexible diaphragm which constitutes a wall of a hydraulic pressure chamber.

Abstract: An improvement in phonograph records, and method of making the same dealing particularly with a record formed in a coating applied to paperboard and normally used as a wall of a carton or the like.

Abstract: A device for pressing storage substrates made of thermoplastic material. It comprises: a press having two plates, a matrix attached to one of the plates, the matrix carrying the data to be stored in said substrate, and, arranged between the plates, one rubber sheet, on polyethyleneterephtalate sheet and a metal film. The superimposition of these different materials ensuring a properly uniform pressure over the substrate.