Abstract: When optical disk defects are managed by using non-defective areas in place of defective areas, different criteria are used for detecting the defects, depending on the type of data recorded on the disk. For example, to avoid interruptions of real-time recording, less strict criteria are used when audio or video data is recorded than when computer data is recorded. The criteria themselves may also be recorded on the disk.

Abstract: An optical disk according to the present invention has data recording tracks of lands and grooves. Each of the data recording tracks has a length corresponding to a revolution of the disk and includes a plurality of track sectors. The data recording tracks of lands and grooves are connected alternately to each other so as to form a continuous data recording spiral. Each of the track sectors has a preformatted identification signal part for representing sector address data and has a data recording part for recording data. The identification signal part has the first address data region and the second address region. The first address data region and the second address data region are shifted by the same predetermined distance from the center of a groove track oppositely in the radial direction of the disk.

Abstract: In a video disk recording/playback device for converting a digital video signal or the like into high-efficiency coded data and recording the coded data on a video disk, or for restoring high-efficiency coded data recorded on the video disk and reproducing an output image, wherein said digital video signal is composed of a succession of video signals of a plurality of frames and including an I picture encoded within a frame, a P picture interframe coded by forward motion compensation with reference to said I picture and/or another P picture, and a B picture interframe coded by motion compensation in both directions with reference to said I and/or P pictures temporally preceding and succeeding the B picture, there are further provided a means for recording in an image information table set up on said video disk all of the start addresses of coded data representing selected images such as images to be retrieved and the start addresses of data containing information required for reproducing the coded data.

Abstract: This invention aims to provide a composite sheet having a layer of inelastically stretchable continuous fibers improved so that a possible unevenness in fiber diameter may be minimized.

Abstract: An optical disk physical has a recording region divided into zones, each zone including physical tracks adjacent to each other. An integer number of sectors are provided in each physical track. The angular recording density is higher in the more outward zones such that the linear recording density is substantially constant throughout the recording region, and logical tracks are formed of a predetermined number of sectors, independent of the physical tracks. The conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from a host device is easy. The addresses written in headers of the sectors in the logical track in which data are actually recorded, including substitute sectors used in place of defect sectors, are preferably consecutive to further facilitate the conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from the host device.

Abstract: A sheet-like fibrous assembly having an inelastic stretchability is intermittently joined to at least one surface of an elastically stretchable sheet. The elastic sheet is elastically stretchable at least 80% in one direction and the fibrous assembly is curved between each pair of binding spots adjacent to each other on the elastic sheet so as to be stretchable in the one direction and comprises ethylene/propylene copolymer, ethylene/propylene/butene copolymer or a mixture of two or more of these copolymers at 100˜10% by weight.

Abstract: An optical disk has a recording region divided into ones, each zone including physical tracks which are divided into a number of sectors. The optical disk further includes a structure management table which stores an attribute for each zone indicating whether the corresponding zone is a recording area which permits rewriting or a recording area that does not permit rewriting.

Abstract: An optical disk according to the present invention has data recording tracks of lands and grooves. Each of the data recording tracks has a length corresponding to a revolution of the disk and includes a plurality of track sectors. The data recording tracks of lands and grooves are connected alternately to form a continuous data recording spiral. Each of the track sectors has a preformatted identification signal part for representing sector address data and has a data recording part for recording data. The identification signal part has a first address data region and a second address region. The first address data region and the second address data region are shifted by the same predetermined distance in opposite directions from the center of a groove track in the radial direction of the disk. The first address data region is set to represent the address of a groove track sector, and the second address data region is set to represent the address of a land track sector adjacent to the groove track sector.

Abstract: In optical disk having a track formed of groove tracks and land tracks connected every revolution to form a single spiral, each revolution-of the tracks is divided into sectors, each having identification signal region at the head of the sector, and the identification signal regions in tracks adjacent to each other are aligned in the radial direction. Prepits are formed in the identification signal region, on an extension of a boundary between groove and land tracks adjacent to each other. The prepits have a width substantially equal to the width of the grooves. The identification signal including address information of the sector. The polarity of tracking error signal is detected at the identification signal region of the recording sector, and whether the recording sector is in a groove track or land track is determined based on the polarity of tracking error signal.

Abstract: An optical disk according to the present invention has data recording tracks of lands and grooves. Each of the data recording tracks has a length corresponding to a revolution of the disk and includes a plurality of track sectors. The data recording tracks of lands and grooves are connected alternately to form a continuous data recording spiral. Each of the track sectors has a preformatted identification signal part for representing sector address data and has a data recording part for recording data. The identification signal part has a first address data region and a second address region. The first address data region and the second address data region are shifted by the same predetermined distance in opposite directions from the center of a groove track in the radial direction of the disk. The first address data region is set to represent the address of a groove track sector, and the second address data region is set to represent the address of a land track sector adjacent to the groove track sector.

Abstract: An optical disc using a single-spiral land and groove track format enabling accurate tracking offset correction and reliable detection of the transition point between a land track and a groove track, and a driving apparatus therefor. Four physical address areas PID1, PID2, PID3, and PID4 are recorded to a header area such that PID1 and PID2 are offset one-half track pitch toward the outside circumference of the disc from the groove track center, and PID3 and PID4 are offset one-half track pitch toward the inside circumference of the disc from the groove track center, and the physical address areas PID1-PID4 can be detected by means of a difference signal in the radial direction. The single frequency pattern area VFO at the beginning of each PID is lengthened by PID1 and PID3, thereby enabling tracking offset correction using a sum signal, and detection of the land-groove transition point using a difference signal obtained from the PID offset.

Abstract: An optical disc using a single-spiral land and groove track format and an address signal enabling simple sector address management and format compatibility with read-only optical disc media is disclosed. Four physical address areas PID1-PID4 are recorded to a header area such that PID1 and PID2 are offset one-half track pitch toward the outside circumference of the disc from the groove track center, and PID3 and PID4 are offset one-half track pitch toward the inside circumference of the disc from the groove track center, and the header area is shared by groove track sectors and land track sectors. A groove track sector address is written to PID3 and PID4, and the sector address of the land track sector adjacent on the outside circumference side of that groove sector is written to PID1 and PID2. The address of each sector increases 1 in the same sequence as the sectors are formed in the recording spiral.

Abstract: An optical disk physical has a recording region divided into zones, each zone including physical tracks adjacent to each other. An integer number of sectors are provided in each physical track. The angular recording density is higher in the more outward zones such that the linear recording density is substantially constant throughout the recording region, and logical tracks are formed of a predetermined number of sectors, independent of the physical tracks. The conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from a host device is easy. The addresses written in headers of the sectors in the logical track in which data are actually recorded, including substitute sectors used in place of defect sectors, are preferably consecutive to further facilitate the conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from the host device.

Abstract: An optical disk physical has a recording region divided into zones, each zone including physical tracks adjacent to each other. An integer number of sectors are provided in each physical track. The angular recording density is higher in the more outward zones such that the linear recording density is substantially constant throughout the recording region, and logical tracks are formed of a predetermined number of sectors, independent of the physical tracks. The conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from a host device is easy. The addresses written in headers of the sectors in the logical track in which data are actually recorded, including substitute sectors used in place of defect sectors, are preferably consecutive to further facilitate the conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from the host device.

Abstract: Proposed is an acrylic rubber composition suitable for hot-air vulcanization under normal pressure with a greatly increased vulcanization velocity. The composition comprises:(1) 100 parts by weight of an acrylic rubber polymer which is a copolymerization product of a monomer mixture consisting of(a) from 1 to 25% by weight of an alkoxy-substituted alkyl (meth)acrylate,(b) from 55 to 99% by weight of an alkyl (meth)acrylate, and(c) from 0 to 20% by weight of a third comonomer selected from several ethylenically unsaturated monomeric compounds;(2) from 0.1 to 20 parts by weight of an alkoxy silane compound having an unsaturated group;(3) from 10 to 200 parts by weight of a reinforcing filler; and(4) from 0.1 to 10 parts by weight of an organic peroxide.

Abstract: An optical disk physical has a recording region divided into zones, each zone including physical tracks adjacent to each other. An integer number of sectors are provided in each physical track. The angular recording density is higher in the more outward zones such that the linear recording density is substantially constant throughout the recording region, and logical tracks are formed of a predetermined number of sectors, independent of the physical tracks. The conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from a host device is easy. The addresses written in headers of the sectors in the logical track in which data are actually recorded, including substitute sectors used in place of defect sectors, are preferably consecutive to further facilitate the conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from the host device.

Abstract: Proposed is an acrylic rubber-based composition suitable for hot-air vulcanization under normal pressure in a continuous process. The rubber composition comprises, besides an acrylic rubber polymer having, in a molecule, at least two silicon-bonded vinyl groups to serve as the crosslinking sites, reinforcing filler and organic peroxide as a vulcanizing agent, an alkoxy silane compound having a vinyl group or (meth)acryloxy group bonded to the silicon atom, such as vinyl triethoxy silane and 3-methacryloxypropyl trimethoxy silane in a specified amount. This unique ingredient serves as a vulcanization accelerator so that the vulcanization reaction is so rapid as to be freed from foaming of the vulcanizate due to the volatile matters and is complete even in the surface layer without the vulcanization-inhibiting influences by the atmospheric oxygen.

Abstract: An improved flame-retardant composition and method for its use are provided. The composition imparts flame retardency to synthetic thermoplastic resins to prevent dripping of the melt of the resin when the resin is burnt. The composition comprises a flame retardant agent such as phosphate ester compound, optionally combined with a metal hydroxide, and an organopoly-siloxane-based graft copolymer of a (meth)acrylic acid ester such as methyl(meth)-acrylate. The flame retardant is used in an amount from 1-50 parts by weight per 100 parts by weight of the synthetic resin, and the graft copolymer provides 0.5 to 20 parts by weight of an organosilicone group per 100 parts by weight of the synthetic resin.

Abstract: The present invention provides a crosslinkable composition which comprises an internally crosslinked acrylic elastomer which is crosslinkable with a peroxide, a fluoroelastomer and a crosslinking agent for at least one of the elastomers.A crosslinkable composition of the present invention can afford a molding which are excellent in physical properties such as mechanical strength and compression set, heat resistance and workability.

Abstract: An acrylic rubbery polymer having remarkably improved cold resistance can be prepared by modification with an organopolysiloxane by the emulsion copolymerization of a monomeric mixture of two acrylic monomers, of which one is, for example, an alkyl acrylate and the other is an acrylic compound having, in a molecule, at least one ethylenically unsaturated group other than acrylic group in an aqueous emulsion of an organopolysiloxane having a substantial amount of mercapto-substituted monovalent hydrocarbon groups bonded to the silicon atoms.