Abstract: According to one embodiment, a multilayer optical recording medium including a substrate, a guide layer group that is provided on the substrate and has guide layers in which positional information in a radial direction is recorded, and a recording layer group that is provided on the substrate and has recording layers in which information can be recorded. In the recording layer group, positional information of the recording layers associated with the positional information recorded in the guide layers and control information of the optical device where reflected light volumes of the laser beams on the guide layers and the recording layers become maximum at the positions in the radial direction are recorded at the positions in the radial direction of the recording layers.

Abstract: An embodiment of the invention, to provide a recording method and a storage medium for BCA data with high reliability for a storage medium and a method for reproducing BCA data from the storage medium, and an information recording apparatus and an information reproducing apparatus. In a conventional optical disk, low reliability data is recorded in a data area of BCA. Thus, the thickness of a film material for use in a recording layer oriented to BCA data or close to the inner periphery of the storage medium in the vicinity thereof is formed in uniform thickness by using a substrate of the storage medium, the substrate being formed by being suctioned by means of adsorbing mechanisms formed in an arc shape so as to integrated two of the adsorbing mechanisms to be adjacent to each other.

Abstract: Efficient recording and reading are achieved in an optical recording medium including servo layers and recording and reading layers. The optical recording medium includes: a first servo layer having a projection and a depression for tracking control that are formed in a first spiral direction; a second servo layer having a projection and a depression for tracking control that are formed in a second spiral direction opposite to the first spiral direction; and a plurality of recording and reading layers having a flat structure with no projection and depression for tracking control. Information is recorded on each of the plurality of recording and reading layers while tracking control is performed using the first servo layer or the second servo layer.

Abstract: A guide-layer separated optical recording medium includes a guide layer with a guide track formed therein and a plurality of recording layers, these layers being separately deposited from each other. A layer position information region for indicating position information of each of the recording layers, is formed on the guide track within a different range of the guide layer for each of the recording layers. Each of the recording layers includes a preformat region having a predetermined signal written on a record track along the guide track, and the preformat region on each of the recording layers is provided in a region corresponding to the layer position information region. An optical recording medium drive apparatus and a recording layer access method for the guide-layer separated optical recording medium are also provided.

Abstract: An optical recording and reading method is provided in which the information necessary for recording and reading layers is quickly acquired to reduce the seek time during reading and recording. The optical recording and reading method is used for an optical recording medium that includes a plurality of recording and reading layers and a servo layer. Information is recorded on or read from the recording and reading layers by irradiating them with a recording and reading beam while the servo layer is irradiated with a servo beam to perform tracking control. When information is recorded on the recording and reading layers, control information necessary for subsequent recording and reading to be performed on the recording and reading layers is recorded on the servo layer 18. When the subsequent recording or reading is performed, the control information on the servo layer is consulted, and then the recording or reading is performed on the recording and reading layers.

Abstract: An optical disc drive according to the present invention can read and/or write data from/on an optical disc with information layers including first and second information layers (L0 and L1). The drive includes: an objective lens for converging a light beam; a lens actuator for driving the lens; a photodetector section that receives the beam reflected from the disc and converts it into an electrical signal; and a control section for determining the values of a first group of parameters, which are set to read data from the first layer (L0), and those of a second group of parameters, which are set to read data from the second layer (L1), during a disc loading process.

Abstract: A fabrication method of a multilayer optical recording medium having a plurality of recording layers, comprises a step of preparing an optical recording medium having at least one record area; a write-position mark generating step of recording write-position marks in the record area beforehand; a step of preparing an optical system including a common objective lens to focus a data recording beam and a position mark recording beam on different positions in a thickness direction of the record area; a first data writing step of writing data between the write-position marks with following the write-position marks by the data recording beam; a position mark recording step of, in parallel with the first data writing step, recording new write-position marks in the record area by the position mark recording beam; and a second data writing step of writing data between the new write-position marks with following the new write-position marks by the data recording beam.

Abstract: An optical information recording medium includes one or more information layers including a recording layer for recording/reproducing an information signal by irradiation with a laser light, and a seperating layer or a protective substate on which a first information layer of the information layer on the irradiation face side is formed. The seperating layer or the protective substrate having a guide groove spirally or concentrically formed on the surface, and the respective inclined planes on the inner perimeter side and the outer perimeter side of the guide groove having inclined angles ? and ? with respect to the bottom face of the guide groove. The guide groove has one or more dissymmetric regions in the radius direction where the inclined angles ? and ? are different. The information layer has roughly agreeing thicknesses in the inclined face portion on the inner and outer perimeter sides in the dissymmetric region.

Abstract: The present invention relates to a holographic disk medium (1) with servo marks (7), and more specifically to a holographic disk medium (1) having a common reflective layer (3) for reflecting a servo beam (9) and object and reference beams (8). According to the invention, a holographic disk medium (1) with a recording layer (2) for recording holograms (6) and a reflective layer (3) for reflecting a servo beam (9) and object and reference beams (8), includes servo marks (7) which are located in the reflective layer (3) at least partly below the holograms (6), wherein the servo marks (7) are designed such that their influence on the object and reference beams (8) is minimized.

Abstract: A hologram recording medium is for recording or reproducing information with light irradiated thereto. The medium has a recording layer made of a photo-sensitive material, a reflective layer disposed on the opposite side of the recording layer from a light irradiated side, tracks formed on the reflective layer such that the tracks are spaced apart by a first pitch from each other to extend without intersection, and positioning marks formed on the reflective layer such that the positioning marks are spaced apart by a second pitch from each other in a direction in which the tracks extend. The second pitch is a function of the first pitch.

Abstract: A magnetic tape comprises a substrate having on one side thereof a magnetic layer serving as a recording surface, and on the other side thereof at least two layers containing inorganic particles which serve as a non-recording surface, wherein said magnetic tape has a region on the side of the non-recording surface along the longitudinal direction of the tape in which a regular pattern for servo tracking having different optical properties from the other major region of the side of the non-recording surface is or can be formed. The layers on the non-recording surface are characterized in that the inorganic particles in the outermost layer are larger than the inorganic particles in the underlying layer(s).

Abstract: A photolithographic process is provided for producing a blank storage disk which includes a reference track pattern. The track pattern provides two edges as reference lines from which distances are determinable for the purpose of laser writing multiple information tracks between adjacent reference track patterns which are preferably spirals (single or interlaced) or concentric circles. The photo-lithographic process is also used to create recording blanks having multiple layers.

Abstract: An optical tape including an optical recording layer for permitting information to be optically recorded thereon and a light-reflective magnetic layer. The light-reflective magnetic layer which reflects light projected onto the recording layer, also permits magnetic recording or magneto-optical recording to be performed thereon, thereby increasing a storage capacity of the optical tape remarkably. Further, the optical tape is provided with a layer to form guiding grooves for tracking control. The layer to form guiding grooves is made up of ultraviolet-hardening resin, photo-resist, or a photochromic material. For example, in the case of using ultraviolet-hardening resin, after a guiding groove pattern has been exposed by projecting an ultraviolet ray on a layer made up of ultraviolet-hardening resin, the exposed areas harden to form areas corresponding to guiding grooves between those exposed areas.

Abstract: An optical recording medium enables an optical pickup to quickly access a plurality of items of information progressing concurrently or to be selected simultaneously. By provision of spiral multitrack formed by multiple winding of a plurality of tracks in a first recording region and concentric-circle track formed in a second recording region adjacent to the first recording region, this invention can implement an optical recording medium in which the distance from the concentric-circle track to each track of the spiral multitrack is shortened, thus enabling an optical pickup to quickly access a desired track at a track jump.

Abstract: An optical recording medium has a track format with a track pitch smaller than a diffraction limit of a light spot so as to realize an increased capacity and a higher density. A guide groove for tracking purposes is formed along each of the concentrically or spirally formed tracks in a periodic intermittent pattern with respect to a circumferential direction of the optical recording medium. The intermittent patterns of the guide grooves adjoining each other with respect to a radial direction of the optical recording medium are displaced in phase from each other. A light spot of a diameter greater than the track width is projected onto the optical recording medium in rotation and the position of the light spot is servo-controlled in the track width direction in such a manner that a light quantity distribution with respect to the track width direction of a reflected or transmitted light of the light spot diffracted by the selected guide groove maintains its symmetry in the track width direction.

Abstract: The method of the present invention is for recording, reproducing, and deleting information on and from an optical disk including a plurality of tracks each having M guide grooves (M is an integer equal to or larger than 2) and M-1 land(s) interposed between the adjacent guide grooves, at least one of the land(s) having a group of pits for producing address information. The method includes the step of: focusing light beams on the respective guide grooves and land(s) for effecting the recording, reproduction, and deletion of information. Such an optical disk is also provided.

Abstract: When a dye material layer is spin-coated on an optical storage medium of the type having grooves fabricated in a substrate thereof, the dye material layer surface has depressions in the vicinity of the grooves. These depressions have a profile which is a function of the distance from the center of the storage medium. To compensate for the radial dependence of the depressions, the geometry of the grooves is changed by varying the base dimension of the groove as a function of the distance from the center of the storage medium. In this manner, the difference in phase for radiation traversing the storage medium by an optical path that includes a groove as compared to an optical path that does not include an associated groove is constant as a function of distance from the center of the storage medium. The phase difference which is a constant as a function of distance from the center of the storage medium is important in the generation of signals used in tracking the groove.

Abstract: A data recording/reproduction method and apparatus uses an optical disk equipped with wobbling track guide grooves disposed in a track scanning direction and minutely wobbled. The apparatus uses a circuit for detecting and correcting displacement of an optical spot position from the wobbling track, and a system for allowing data to correspond to front and rear edges of recording pits as a recording system, and includes a circuit for independently handling reproduction pulses obtained from reproduction signals of the recording pits on the front and rear edge sides and for generating reproduction clocks. A circuit resynthesizes the two series of reproduction pulse trains by a specific pattern portion in the data. Another optical disk apparatus divides each track into zones, and switches a rate of revolution each zone to attain a substantially equal linear velocity. A servo signal reproduction clock generation circuit and a data signal recording/reproduction clock generation circuit are disposed separately.

Abstract: An optical recording medium formed of a pre-grooved substrate provided with a recording layer formed on the groove, in which the groove has a shape to satisfy the condition I.sub.Gr /I.sub.0 .gtoreq.0.85, where I.sub.0 represents the reflected light quantity from the mirror surface and I.sub.Gr represents the reflected light quantity from the groove surface when the laser beam is concentrated to a spot size of approximately 1 .mu.m on the surface of the medium, and to enable three-spot tracking to be performed. According to this invention, the CN ratio as the measure of noise in an optical recording medium can be improved.

Abstract: An optical recording medium is formed by applying a coating liquid to form a light-reflecting layer on a substrate having a surface provided with a pre-format pattern comprising a concavity and a convexity. The concavity is designed to have a sectional shape of a trapezoid having a pair of parallel opposite sides, a shorter one of which constitutes the bottom of the concavity, and a pair of sloping sides. Each sloping side forms a (solid part) angle .theta. of not larger than 35 degrees with respect to the extension of the substrate surface. The concavity has a depth d larger than .lambda./4n wherein .lambda. is the wavelength of an optical radiation beam with which the optical recording medium is illuminated for recording and/or reproduction and n is the refractive index of the substrate.

Abstract: A write once-type recording medium with a guide groove has a first management data for constantly managing a position of a track in the groove after data-writing/reading is excuted and a second management data for managing the data-writing, both optically recorded on a position in the groove displaced from that position.

Abstract: An optical information recording medium, such as an optical disk, includes a meandering guide groove being varied in period according to first additional information and in amplitude according to second additional information. The optical information recording medium enables recording a plurality of kinds of information in addition to the first and second additional information in accordance with a multiple recording system.

Abstract: An optical information storage medium is used for recording optical information therein and reproducing optical information therefrom. The optical information storage medium includes parallel, concentric, or helical tracking guide grooves and information tracks defined between the tracking guide grooves. A preformat area composed of discrete pits is disposed on some of the information tracks. The tracking guide grooves and the preformat pits are defined in one surface of a transparent substrate, and a recording film capable of absorbing and reflecting light is disposed on said one surface of the transparent substrate. The ratio of the effective depth of the tracking guide grooves to the wavelength of a recording/reproducing laser beam within the transparent substrate is in a certain range, and the ratio of the effective depth of the preformat pits to the wavelength of the recording/reproducing laser beam within the transparent substrate is also in a certain range.

Abstract: An optical recording disk comprises a base plate, a flat layer, an optical recording layer and a protection layer which are laminated in this order. The flat layer has a flat surface which contacts with the optical recording layer to thereby enable the optical recording layer to have a uniform thickness over the layer and make the surface of the optical recording layer flat. At least one of the other layers constituting the above optical disk other than the optical recording layer comprises a material capable of recording and reproducing information, such as a magnetooptic material, a phase-change material, an organic pigment and a pit-formable material in which the information is recordable.

Abstract: In an optical recording medium a substrate is provided having at least a recording surface and a recording layer on an area of the recording surface having a length in a longitudinal direction. A set of linear continuous tracking tracks is formed on the recording surface. The tracking tracks have a length which is greater in the longitudinal direction than the length of the recording layer with a constant distance between adjacent tracks, which distance is equal to or larger than twice the width of each track. Recording areas are arranged and constructed so as to record information irradiated with a light beam. Each of those areas is positioned between neighboring tracking tracks.

Abstract: An information recording disk for recording an information signal along a track defined by a depression on the disk as a change of physical property of a recording material deposited on the track comprises a disk-shaped glass substrate made of a glass and carries a groove corresponding to the track. The groove has a surface roughness substantially smaller as compared to the surface roughness caused at a bottom surface of a groove on a silica glass substrate when both the disk-shaped glass substrate and silica glass substrate are dry-etched under same conditions. The disk-shaped glass substrate comprises SiO.sub.2 component and one or both of Al.sub.2 O.sub.3 and BaO components with substantially no alkali components. Further, a recording layer comprised of the recording material which changes in physical property responsive to a projected energy beam is deposited on the substrate such that the depression is formed in correspondence with the track.

Abstract: An optical disk of the type including guide grooves is improved by regulating the width of the grooves, and thus the width of the adjacent land portion, in accordance with the type of information recorded at that part of the land.

Abstract: An optical recording medium in tape form which may either be strips of tape or reels of tape, all having preformatted continuous servo tracks from one end to the other. Preformatted servo tracks are spaced-apart lines, so as to permit data spots to be written between or on the tracks. The tracks may extend either longitudinally, parallel to the lengthwise direction of the tape or in a perpendicular direction, extending in directions transverse to the length of the tape, or in a grid-like pattern. The tape web may be joined to a web of transparent protective material over the surface of the strip. A data card may be made using a strip of such tape without regard to registration of the tape with markings on the card. Tracks may be made by directly writing with a laser on direct-read-after-write laser recording material or by photolithography or by embossing.

Abstract: An optical recording medium having a plurality of tracks juxtaposed each other and capable of easily and rapidly detecting a desired track. An optical recording medium includes a data recording region in which the tracks are juxtaposed each other and a track detecting region provided at a part of the data recording region. The track detecting region includes track guides juxtaposed along respective tracks and track number guides corresponding to a locus of the movement of an optical head in the access to a desired track, the track number guides intersecting the track guides.

Abstract: The invention relates to optical memories making use of optical interaction between an incident ray and an information medium (83) capable of having data written thereon and of having data read therefrom, which data is organized in a adjacent track elements which are marked by prerecorded patterns. The invention provides an information medium (83) and a reader device therefor (84, 85, 86, 87, 88) including means (89, 91, 92, 93, 94) for sampled tracking of the track elements on the basis of patterns which are offset from the track scan line, said patterns forming discontinuous periodic wave sequences whose offset edges are symmetrically disposed about the middle of the inter-track gap. The invention is particularly applicable to optical memories using a preformated disk capable of recording, of being read, and where appropriate of being erased, with data in digital form.

Abstract: An optical memory element comprising a substrate with grooves functioning as grooves for, for example, controlling the position of a laser beam, wherein said substrate is composed of a glass containing SiO.sub.2 in the range of 51 to 71% by weight, Na.sub.2 O in the range of 10 to 18% by weight, K.sub.2 O in the range of 0 to 8% by weight, Al.sub.2 O.sub.3 in the range of 12 to 22% by weight, and B.sub.2 O.sub.3 in the range of 0 to 9% by weight.

Abstract: A disc comprises a recording surface which is divided into a plurality of equiangular sectoral regions and a guide track formed on the recording surface. Each track turn of the guide track is constituted by a row of pits formed in every other equiangular sectoral regions, and the pit is only formed in one of two mutually adjacent track turns of the guide track in each equiangular sectoral region so that the pits are formed in every other track turns in a radial direction of the disc in each equiangular sectoral region.

Abstract: An optical disk substrate has a surface on which a pre-groove for light beam tracking is formed. Non-pregrooved regions on the substrate surface on which the pregroove is formed are subjected to surface roughing processing to improve adhesion of the substrate surface in the non-pregrooved regions to a film which is to be overlaid on the optical disk substrate.

Abstract: The invention relates to an article comprising a glass sheet and having an etched pattern, and to a process of manufacturing an article comprising a glass sheet and having an etched pattern.The glass sheet 11 is a chemically tempered glass sheet, and the pattern comprises one or more grooves 10 etched into the article using fluorine ions to a depth of less than 2 .mu.m. The etched grooves 10 constituting the pattern may be formed in a layer 12 of inorganic material such as SiO.sub.2. They may have a width of less than 10 .mu.m and the spacing (p) between two adjacent grooves may also be less than 10 .mu.m.

Abstract: An optical disk exclusively used for reproduction has an optically detectable guide groove in which signals have previously been recorded. One type of optical disk exclusively used for reproduction is interchangeable with an optical disk which allows both recording and reproducing operations or enables information recorded thereon to be erased. If such an optical disk is not provided with a guide groove in an unrecorded region remaining between a data managing information region and a data recording region, problems may arise when the optical head of an optical disk apparatus is positioned in the unrecorded region at the time of starting the operation of the apparatus and when the optical head effects retrieval between the data managing information region and the data recording region.

Abstract: An optical information recording medium in the form of a card having tracking tracks for obtaining a tracking signal and clock tracks for obtaining a clock signal arranged alternately and record zones for recording information between each of the tracking tracks and each of the clock tracks, and apparatus for recording/reproducing information using the recording medium.

Abstract: A digital information recording and reproducing method for significantly improving the transfer rate of digital information, comprises the steps of: forming a plurality of light beam guide tracks on a recording medium capable of multiple light-wavelength recording, the tracks being spaced apart by a predetermined pitch and each of the tracks comprising a series of pre-pits disposed in a scan direction and spaced apart by an interval longer than the diameter of a spot of a light beam for use in recording and reproducing; and recording and reproducing an information bit by changing the light beam to have a different wavelength predetermined n times in a predetermined order while the light beam is scanned by one interval of the pre-pits.

Abstract: A method of manufacturing an optical memory element, which includes the steps of applying a first photo-resist layer onto a glass substrate for an optical memory element, laying a mask plate on the glass substrate applied with the first photo-resist layer, with the mask plate being prepared by covering a surface of a transparent substrate with metallic layers formed into a guide pattern configuration, irradiating ultraviolet rays onto the first photo-resist layer through the mask plate, transferring the guide patterns of the mask plate onto the first photo-resist layer, and engraving the guide patterns in the glass substrate by etching after developing the first photo-resist layer.

Abstract: A reflection-type optical recording medium which has a surface on which track guide grooves are formed and in which a layer of a recording material that has an increased energy reflection coefficient in a write portion. The track guide grooves are formed with a depth .phi..sub.0 so that improved efficiency results because of the selection of various parameters of the system.

Abstract: In an optical disk, a light reflective layer is formed on a transparent substrate, and a groove serving as a tracking guide is formed on the surface of said light reflective layer, continuously extending along the circumference of the optical disk. Pits are formed in a light reflective layer on the bottom surface of the tracking guide. The depth and width of said groove are ##EQU1## and w0/2, respectively, and those of said pits are ##EQU2## and w0/3, respectively, where .lambda. is the wavelength of a laser beam, w0 is the diameter of a laser beam spot on the optical disk, and n is an integer.

Abstract: An optical storage medium incorporates stacked servo and data layers with the pattern of the servo layer being prepared prior to preparation of the data layer. The servo pattern comprises an undulation in a very thin film of high optical index material on the surface of the substrate of the medium. The undulating layer containing the servo pattern is separated from the active layer of the medium by a thin dielectric spacer film. The data layer is employed for formation of vesicular, or ablative or other marks forming surface discontinuities formed by any of the usual pit forming techniques. The preformatted servo information formed in the servo layer as buried undulations in the thin film is read out in amplitude or phase contrast. The thin undulating layer is of a significantly different index of refraction from the substrate and the next intervening layer. This layer can be transparent or semi-transparent.

Abstract: The invention comprises an improved optical recording medium and information record wherein the light sensitive layer comprises a tracking layer having one or more openings extending therethrough and an absorber layer overlying the tracking layer and the openings therein thereby forming first and second regions of the light sensitive layer having different reflectivities which can be used to provide radial tracking information.The method of the invention includes the steps of depositing a tracking layer onto a light reflective layer, forming one or more openings through the tracking layer and depositing an absorber layer over the tracking layer and into the openings therein.

Abstract: In an optical disk having an optical recording layer which is capable of having information thereon using a laser beam with information superposed by modulation there is formed a spiral protruding or recessed track having a width equal to about half or less of the wavelength of a laser beam to be used, this track being utilized as the guiding track of the laser beam. A method for manufacturing such an optical disk is also disclosed according to which a recessed track for tracking is formed by plastic deformation of the upper surface of an original disk with a hard processing stylus such as a diamond stylus. The original disk thus produced is utilized for forming an optical recording disk having a protruding or recessed guiding track.

Abstract: In an optical disk having an optical recording layer which is capable of having information thereon using a laser beam with information superposed by modulation there is formed a spiral protruding or recessed track having a width equal to about half or less of the wavelength of a laser beam to be used, this track being utilized as the guiding track of the laser beam. A method for manufacturing such an optical disk is also disclosed according to which a recessed track for tracking is formed by plastic deformation of the upper surface of an original disk with a hard processing stylus such as a diamond stylus. The original disk thus produced is utilized for forming an optical recording disk having a protruding or recessed guiding track.

Abstract: A rotary recording medium has an information signal along a spiral main track comprising a multiplicity of successively adjacent track turns of respective track turn numbers, first and second reference signals of different frequencies are recorded alternately in the radial direction of the recording medium and along reference signal tracks disposed centrally between the centerlines of mutually adjacent track turns, and a third reference signal is recorded at points where the track turn numbers change at every revolution of the recording medium. The rotary recording medium comprises, over a plurality of track turns in a specific part of the main track, displacement part for displacement of a reproducing tracing element in which displacement parts only either one of the first and second reference signals has been recorded along reference signal tracks on both sides of each of said plurality of track turns.

Abstract: A holographic video disc system is described in which the baseband information for successive horizontal television line intervals is recorded as successive holograms of one-dimensional line images in a spiral track on the surface of a disc of material. A spiral guiding track is also formed in the surface of the disc immediately adjacent to the spiral track of holograms. The recording system includes a laser beam which is modulated with the baseband video information. The beam is divided into a reference beam and a data beam. A beam deflector scans the data beam through a chosen angle at the horizontal television sweep rate, while the reference beam is unaffected. The reference beam and data beam are intersected at the surface of a record medium and form a surface relief hologram on that surface.