Abstract: A method for preparing a substrate sheet for an optical recording medium has the steps of controlling a roll stamper having a preformat pattern on the peripheral surface thereof and a molding roll disposed with a predetermined gap between the same and the roll stamper so that they have a predetermined temperature, feeding a thermoplastic resin heated to a predetermined temperature to the gap from a means for extruding the thermoplastic resin disposed on the upstream side of the gap, while the roll stamper and the molding roll are rotated at a predetermined rotational frequency, and then molding the thermoplastic resin into a sheet by pressing the resin between the roll stamper and the molding roll to transfer the preformat pattern to the resin.

Abstract: A roll stamper used in a process of continuously forming a uniform sheet of a resin from which information recording medium bases are obtained. This roll stamper has a stamper member having in its surface a pattern corresponding to a pre-format pattern of an information recording medium, fixing members fixed on opposite end portions of a reverse surface of the stamper member so as to be integral with the stamper member, and a specular roll base having an engagement groove formed in its circumferential surface parallel to its axis. The stamper member is fixed on the specular roll base by fitting the fixing members in the engagement groove. A recess formed in a circumferential surface of the roll stamper as a gap between the fixing members is filled with a filler so that the roll stamper circumferential surface is substantially smooth. Side surfaces of the fixing members and/or the engagement groove are shaped as to suitably retain the filler.

Abstract: A method for molding a substrate sheet for an optical recording medium by transferring a preformat pattern from a molding roll to a resin sheet molded by melting and extruding a resin. The molding roll has a roll base, a stamper detachably fixed on the peripheral surface of the roll base, and a resin layer interposed between the roll base and the stamper.

Abstract: A signal receiving coil device for an MRI apparatus, to be fitted to a patient for detecting nuclear magnetic resonance signals, comprising a coil member assuming a substantially cylindrical shape when fitted to the patient and having at least one flexible section and at least one rigid section disposed sequentially and alternately in a circumferential direction of said cylindrical shape; a first coil unit disposed on the coil holding member, and having a signal receiving direction thereof crossing substantially orthogonally the direction of a static magnetic field generated by the MRI apparatus when the coil holding member is fitted to the patient; and a second coil system disposed on the coil holding member, and having a signal receiving direction of reception thereof crossing substantially orthogonally both of the direction of the static magnetic field and the signal receiving direction of the first coil unit when the coil holding member is fitted to the patient.

Abstract: A roll stamper which molds a substrate resin sheet into an information recording media by continuously transferring preformat patterns on the substrate resin sheet, and a production process therefor. The preformat pattern on the roll stamper has a value of b/a of greater than 1 when the length of the preformat pattern in a direction parallel to the direction in which the resin sheet is transported is defined as a and the length in a direction perpendicular thereto as b.

Abstract: An apparatus and method for manufacturing a substrate sheet for information recording mediums having a roll stamper consisting of a flexible stamper having a pattern corresponding to a preformat for an information recording medium, the flexible stamper being fixed along the corresponding periphery of a roll substrate. A roll is placed opposite the roll stamper. A molten-resin sheet wider than the flexible stamper member is formed. The apparatus has means for bringing the edges of a resin sheet into contact with the roll substrate before releasing the resin sheet from the roll stamper. The temperature is controlled, so that a temperature difference on the surfaces of edges of a resin sheet and a preformat pattern transfer area of the resin sheet is kept within 30.degree. C. when the resin sheet is separated from the roll stamper after the molten-resin sheet has been pressed between the roll stamper and roll.

Abstract: A roll stamper for forming a substrate sheet for information recording mediums has a flexible stamper member having a pattern corresponding to a preformat for an information recording medium; a first fixing member and a second fixing member respectively joined to both ends of the stamper member in an integral form; and a pair of fit grooves capable of fittingly receiving the fixing members, formed in the periphery of a specular roll substrate in parallel to the axial direction of the specular roll substrate. The fixing members are so fitted to the fit grooves that the stamper member is fixed along the periphery of the specular roll substrate between the fit grooves.The first fixing member has a first member showing a coefficient of linear expansion substantially equal to the coefficient of linear expansion of the stamper member and a second member having a larger coefficient of linear expansion than the coefficient of linear expansion of the first member.

Abstract: A roll stamper for forming an information recording medium substrate has a stamper member having a pattern corresponding to a pre-format for an information recording medium formed in its obverse surface, fixation members fixed to both end portions of a reverse surface of the stamper so as to be integral with the stamper member, and fit grooves formed in a circumferential surface of a specular roll base parallel to the axis of the specular roll base. The fixation members are fitted in the fit grooves, and the stamper member is fixed on the circumferential surface of the specular roll base. The roll stamper also includes a mechanism for applying a tensile force to the stamper member. This roll stamper is used in an apparatus having an extruder for melting and extruding a resin to form a resin sheet and a specular roll facing the roll stamper to continuously form the information recording medium substrate.

Abstract: In a transversal type equalizer having a series connected delay elements, multipliers are coupled with each output of each delay element and an adder adds outputs of the multipliers to provide an equalized output signal for equalizing a time division radio receive signal for every burst in mobile communication. A receive memory (11) stores the receive signal. A transversal type equalization process circuit (77a) is coupled with the output of the memory (11). A output memory (100) stores on equalized output signal. In training tap coefficients of a transversal filter, a tap or a delay element is precluded when an absolute value of a tap coefficient is less than a predetermined value, so that calculation amount for updating tap coefficients is decreased and tracking characteristics are improved.

Abstract: RF coils for a nuclear magnetic resonance device having following features separated or combined at an intersecting portion of two conductive loops disposed so that sensitive directions thereof are substantially perpendicular to a direction of a static magnetic field and that the conductive loops intersect each other with a predetermined interval; (1) conductors of conductive loops are narrowed; (2) neighborhood of intersecting portion is grounded; and (3) a member having a small dielectric constant is put inside of an intersecting portion.

Abstract: A process for producing a resin molding having a concave-convex pattern on the surface includes the steps of providing an original die having a concave-convex pattern on the surface and a substrate having a flat surface, thereby counterposing the concave-convex pattern surface and the flat surface to each other through a spacer and forming a cell with a cavity formed by the original die, the substrate and the spacer; making an internal pressure of the cell cavity lower than an external pressure thereof, thereby filling at least one of a liquid polymerizable component and a liquid resin into the cavity due to a pressure difference between the external pressure and the internal pressure; curing at least one of the polymerizable component and the liquid resin in the cavity, thereby making a replica; and peeling the original die from the replica, thereby obtaining a resin molding.

Abstract: A process for producing a roll stamper which molds a substrate sheet for information recording mediums by continuously transferring preformat patterns on a resin sheet. The roll stamper has the feature that the preformat pattern on the roll stamper has a value b/a of greater than 1, where the length of the preformat pattern in the direction parallel to the direction in which the resin sheet is transported is defined as a and the length in the direction perpendicular thereto as b.

Abstract: A substrate for an optical card having tracking grooves in a stripe form formed on the surface of an extrusion-molded thermoplastic resin sheet is characterized in that the direction of the tracking grooves is in parallel to the extrusion direction of the thermoplastic resin sheet, and the recording or reproduction using the optical card is characterized by that the optical card is bent and reciprocally moved along the direction of tracking grooves.

Abstract: An optical card comprises a transparent substrate having a track groove on its surface, an optical recording layer provided on said track groove, and an opaque card substrate provided in such a manner that it may be contiguous to said optical recording layer, wherein an unrecordable part is provided at an end of said track groove formed on the surface of the transparent substrate.

Abstract: A roll-stamper for forming substrates of an information-recording medium includes at least one stamper being fastened along a peripheral face of a mirror roller, carrying on a surface thereof patterns each corresponding to a preformat for an information recording medium, also having stoppers fixed along both edges on the reverse side thereof, and being fastened to the mirror roller by inserting the stoppers respectively into negative stopping-grooves cut into the mirror roller in parallel with the axis of the mirror roller.

Abstract: Disclosed are a master holder of a stamper electroforming apparatus and an electroforming method using this master holder. The master holder is for use in a stamper electroforming apparatus that forms a metal film by electroforming on a conductive film formed on a master having a minute relief pattern on its surface; and this master includes: a contact ring for electrically connecting the conductive film to a power source; and a structure for controlling the rate at which the metal film is formed, which structure is provided on the contact ring and adapted to control the metal-film-formation rate such that the thickness of a peripheral portion of the metal film gradually decreases in the vicinity of the contact ring.

Abstract: An optical recording medium for performing writing and reading on a pit by use of a light of beam comprises an optical recording layer comprising a porous layer.

Abstract: A process for preparing a substrate sheet for optical recording mediums includes the steps of extruding a molten resin to form a resin sheet and bringing the resin sheet into pressure between a preformat roll and a roll disposed opposingly to said preformat roll to transfer a preformat pattern to the surface of the resin sheet, wherein the roll disposed opposingly to the preformat roll includes a roll whose surface is covered with an elastomeric resin.

Abstract: An optical recording medium for performing writing and reading on a pit by use of a light of beam comprises an optical recording layer comprising a porous layer.

Abstract: An optical recording medium for writing and reading information by use of a beam of light comprises an optical recording layer comprising a light-reflective layer and a light-absorptive layer having been preformatted in the form of grooves.