Abstract: Improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure.

Abstract: Improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure.

Abstract: A method to produce improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. The method includes dual and/or dithered beam writing onto the structure and improved composition of the active layer of the structure.

Abstract: An apparatus to produce optical recording structures displaying improvements in the shape of three-dimensional features displayed therein. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. The apparatus may include dual and/or dithered beam writing elements.

Abstract: An embedded system in a communication network includes a memory for storing data received from the communication network, and a media access controller for determining whether the data received from the communication network is broadcast data or non-broadcast data. A data controller is also provided in the embedded system and includes a first channel for storing a predetermined amount of broadcast data received from the communication network in the memory, and a second channel for storing non-broadcast data in the memory.

Abstract: A method to produce improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. The method includes dual and/or dithered beam writing onto the structure and improved composition of the active layer of the structure.

Abstract: Improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure.

Abstract: Disclosed are improvements in the transverse sectional shape of three-dimensional features displayed in optical recording structures—discs, cylinders, cards, multi-layered devices and structures replicated from them—to increase Figure of Merit. The cross-sectional shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure. Disclosed methods include dual and/or dithered beam writing onto the structure and improved composition of the active layer of the structure. Also disclosed are apparatus for producing such improved features on optical recording structures, according to one or more of the disclosed methods.

Abstract: A video disc member is described having a uniform value of birefringence over the entire information storage surface of the disc. This value of birefringence is the same at the inner information storage radius as at the outer information storage radius. The preferable composition of the video disc is a specially prepared polymethylmethacrylate, referred to as PMMA. The method of molding the improved video disc member includes an extended drying time for said composition and increasing the melting temperature. The increase in melt temperature provides a low and uniform value of birefringence. The improved drying cycle eliminates splay marks, blisters and other surface imperfections as compared to manufacturer recommended drying times.

Abstract: An injection molding apparatus for use in producing centrally-apertured video disc records. The apparatus includes first and second mold halves reciprocally movable with respect to each other between a closed position, wherein the two mold halves are in proximity to each other and molten plastic material is injected into a planar, annular cavity defined therebetween to form the record disc, and an open position, wherein the two mold halves are spaced apart from each other and the molded record disc can be removed. The molding apparatus further includes first and second annular rings carried by the respective first and second mold halves and defining the outer perimeter of the cavity.

Abstract: Heated material is injected into an annular cavity, defined by a pair of mold halves, through a sprue passage, defined by a sprue bushing and an end portion of a punch. The annular cavity and the sprue passage form, respectively the centrally apertured part and a sprue. After partial cooling of the heated material, the punch is locked in place while the annular cavity is displaced relative to the sprue passage so that the sprue is severed from the part along the peripheral surface of the punch end portion. The mold halves are separated to open the annular cavity while the sprue is resting on the punch end portion, and while the part is held by the punch end peripheral surface. After the mold halves are separated, a sprue ejector member is actuated to eject the sprue from the punch end portion. The finished video disc is then removed, carried by the moving platen of the moving mold assembly.

Abstract: Heated material is injected into an annular cavity, defined by a pair of mold halves, through a sprue passage, defined by a sprue bushing and an end portion of a punch. The annular cavity and the sprue passage form, respectively, the centrally apertured part and a sprue. After partial cooling of the heated material, the punch is locked in place while the annular cavity is displaced relative to the sprue passage so that the sprue is severed from the part along the peripheral surface of the punch end portion. The mold halves are separated to open the annular cavity while the sprue is resting on the punch end portion, and while the part is held by the punch end peripheral surface. After the mold halves are separated, a sprue ejector member is actuated to eject the sprue from the punch end portion. The finished video disc is then removed, carried by the moving platen of the moving mold assembly.