Abstract: An object of the present invention is to provide a material having spectroscopic properties, light resistance, solubility and thermal decomposition properties suitable for recording for DVD-R. More specifically, the present invention provides squarylium compounds in a state of a metal complex represented by the general formula (I): wherein, R1 and R2 are the same or different, and represent an alkyl group optionally having a substituent, an aralkyl group optionally;,having a substituent, an aryl group optionally having a substituent, or a heterocyclic group optionally having a substituent; Q represents a metal atom with a coordination ability; q represents 2 or 3; and A represents an aryl group optionally having a substituent, a heterocyclic group optionally having a substituent, or Y═CH— wherein Y represents an aryl group optionally having a substituent or a heterocyclic group optionally having a substituent.

Abstract: A phase change optical disk has a multilayered structure obtained by sequentially forming at least a lower dielectric layer, recording layer, upper dielectric layer, and reflective layer on a substrate. The reflectance Rc of the disk with respect to light with a wavelength of 380 nm to 430 nm, when the recording layer is in a crystalline state, is lower than the reflectance Ra of the disk when the recording layer is in an amorphous state.

Abstract: Preformatted areas in at least the most distal recording layer from an object lens among a plurality of recording layers in an optical disc include guard areas at both ends of the respective recording layer in the tracing direction. No data is recorded on the guard areas. The guard area length GL is determined to satisfy the following formula: GL≧YL+T×(NA/n)/[1−(NA/n)2]1/2 where YL is a maximum allowable value of position deviation between the preformatted areas in the most distal recording layer and in another recording layer in the tracing direction; NA is the numerical aperture of the object lens; T is a distance between the most distal and the another recording layer; and “n” is an refraction index of a medium between the most distal and the another recording layers.

Abstract: Disclosed herewith is a method for enabling fast and high density recording of information. A voltage is applied to a recording layer formed between a pair of electrodes. The distance between the pair of electrodes is set wider at one of land and groove areas of a subject optical disk and narrower at the other or the distance is set so that light absorption occurs only in either of the land and groove areas. The optical disk is also provided with a layer of which light absorption spectrum changes according to the application of an electric current, thereby absorbing the light. The new layer may be the recording layer itself or a layer adjacent to the recording layer. Because a heat generates only from a small area of the optical disk at the time of recording, the disk can be turned rapidly and permissively to the auto focusing and tracking offsets, thereby enabling fast and high density recording. The disk can thus be formed with easily selectable multiple layers.

Abstract: A digital versatile disc (DVD) includes a read-only ROM area in which video is previously recorded, and a readable/writable RAM area. A lender DVD apparatus writes a playback/recording control program in the RAM area of the DVD to be rented. A user DVD apparatus reads the playback/recording control program from the RAM area of the rented DVD. Following the playback/recording control program, the user DVD apparatus receives digital broadcasting, extracts commercial messages therefrom, and writes the extracted commercial messages in the RAM area. Then, the user DVD apparatus reads the video from the ROM area and the commercial messages from the RAM area for playback. Then, the user DVD apparatus generates history data indicating how many times and which commercial message has been played-back, and writes the generated history data in the RAM area.

Abstract: The optical recording medium of the present invention is a phase change optical recording medium which can be used as a write once medium and which can be recorded at a high recording density. The optical recording medium of the present invention is adapted for recording such that, when the recording beam has a wavelength of &lgr;, and objective lens of recording optical system has a numerical aperture of NA, minimum record marks formed are circular or ellipsoidal marks having a length of 0.4&lgr;/NA or less; and the medium is a write once medium wherein the recorded information can not be erased or rewritten at the minimum linear velocity used.

Abstract: Tracking control is carried out by a push-pull method or by mechanical feed at the time of recording signals, and tracking control is carried out by a phase difference tracking method at the time of reproduction. Thus, a phase change type optical disk which enables phase difference reproduction and is erasable may be realized. In a phase change type optical disk having a phase difference reproduction structure, servo mechanism at the time of reproducing signals may be stably controlled by causing the reflectance of a blank portion to be higher than the reflectance of a recording mark portion.

Abstract: An optical disc includes a substrate, and a recording layer and transparent layer formed in this order on the substrate. A light is incident from the transparent layer to write and/or read an information signal. The substrate comprises a first resin layer forming a surface of the substrate on which the recording layer is formed, and a second resin layer having a higher flexural modulus is formed on the first resin layer.

Abstract: The present invention relates to an optical recording medium having a protective layer and a phase-change recording layer on a substrate, said protective layer containing a metallic oxysulfide and an optical recording medium having a protective layer and a phase-change recording layer, said protective layer being formed by sputtering using a target comprising a metallic oxysulfide.

Abstract: An information recording medium includes a structure fabricated by successively depositing a first protective layer, a first interface layer, a recording layer, a second interface layer, a second protective layer, an absorptivity control layer and a thermal diffusion layer on a substrate which is placed on a laser-beam-incident side of the medium, in which the first interface layer and the second interface layer are formed so as to contain elements Bi, Sn, Pb, etc. having the effect of promoting the crystallization of the recording layer and the total content of the elements in the first interface layer is set lower than that in the second interface layer, thereby reducing playback signal deterioration after frequent rewriting.

Abstract: The present invention is a multilayer optical disc formed of a plurality of information recording sections having a phase change recording layer. A first information recording section provided at a laser-incident side uses, as a recording material, a phase change recording material which uses Sb and Te as major components and satisfies their ratio of 2.3<Sb/Te≦4.0 according to the atomic ratio. Since this phase change recording material provides a fast crystallization speed, it is possible to stably record, reproduce, and rewrite an information signal at a high transfer rate.

Abstract: An information recording method including irradiating a phase change recording layer of an optical recording medium with either a multi-pulse laser light train having a recording power of Pw or laser light having an erasing power Pe to record a mark having a length nT in the recording layer, wherein n is an integer of from 3 to 14 and T represents a clock cycle, wherein the multi-pulse laser light train has a constitution such that a heating pulse and a cooling pulse are alternated and the number of heating pulses and the number of cooling pulses each increases by 1 when n increases by 2, and wherein when n is from 6 to 14, the last heating pulse and last cooling pulse have a pulse width of from 0.5T to 0.9T and from 0.7T to 1.5T, respectively.

Abstract: A phase change recording medium comprising an as-deposited first recording layer configured to undergo a reversible phase change between an amorphous state and a crystalline state due to light irradiation and thereby change an optical characteristic. The as-deposited first recording layer includes a plurality of fine nuclei having an average size of 0.5 nm to 4 nm in the amorphous state.

Abstract: There is disclosed an optical information recording medium having phase-change recording films whose the transmittance can be made substantially uniform irrespective of the presence or absence of recording. There are also disclosed methods for recording, reading, and erasing information well at a high density on such a medium. Each of the phase-change recording films other than the top one has a phase-change recording film for recording and erasing information by a phase change caused by illumination of laser light. A transparent upper protective film is formed on the phase-change recording film to protect the phase-change recording film mainly against thermal deformation during recording and erasing of information. A transparent lower protective film is formed under the phase-change recording film to protect the phase-change recording film mainly against thermal deformation during recording and erasing of information.

Abstract: A system and method for defining rewriteable data storage media defined by ECMA Standard ECMA-272 2nd edition (1999) for 120 mm DVD rewriteable disk (DVD-RAM) as a write once data storage media and for storing data thereon. The apparatus consists of a data storage device for reading and writing data on the media, the media, a media type indicator in the media, two write protect flags in the user data area of the media, and programming to examine the two write protect flags prior to a write, erase, or format operation. If both flags match and the media type indicator is write once, the drive is prevented from writing to the user data area if both flags are in the data written state. If both flags do not match after two re-reads, an error message is generated. If both flags are in the data unwritten state, data is written to the user data area and both flags are set to the data written state.

Abstract: A multi-layered optical disc having its recording unit comprised of plural information recording layers, in which two or more information recording layers are layered on a substrate 0.3 to 1.2 mm in thickness, with the interposition of a transparent layer, to form a recording unit, a light transmitting protective layer is formed on the recording unit to a thickness of 10 to 177 &mgr;m and in which the light is illuminated from the side of the light transmitting protective layer to effect recording and/or reproduction of information signals. At least one of the information recording layers except the information recording layer formed at a remotest position from the light transmitting protective layer has a phase change material as a recording material.

Abstract: An information recording medium has a substrate and a recording layer on the substrate, the recording layer is partially transformable between a crystalline state and an amorphous state by being partially heated and cooled so that a signal is recorded in the recording layer by the partial transformation, and the recording layer includes oxygen.

Abstract: A dye record disc has a disc shape substrate having a track-forming surface divided into a read-only area and a recordable area. A reproducing track is formed on the track-forming surface in the read-only area, and has a plurality of pits, each of the pits comprising a dye material, and having a shape corresponding to the reproducing information. A recording/reproducing track is formed on the track-forming surface in the recordable area, and extends continuously, the recording/reproducing track comprising the same dye material as each of the pits.

Abstract: A multilevel recording method based on a novel principle utilizing a phase change medium. The method comprises the steps of: radiating a recording energy beam against an information recording medium having a recording layer to locally melt the recording layer, the recording layer being adapted to produce a phase change between a crystalline state and an amorphous state upon being radiated with an energy beam; and forming an amorphous mark by cooling during a solidifying process to record information in the medium; wherein the size of the amorphous mark is controlled mainly by a competition between a recrystallization process and an amorphization process during the solidifying process; wherein an intensity of reflected light from a reproducing light beam radiated region is controlled in three or more multiple recording levels according to an optical characteristic difference between a crystalline region and a amorphous region and their areas.

Abstract: A phase-change recording medium of the present invention includes a reflection layer, a first protective layer, a phase-change recording layer which changes in phase between a crystallization state and an amorphous state by irradiation of a laser beam, and a second protective layer. The phase-change recording layer contains a component expressed by MzSiy(SbxTe1-x)1-y-z (where 0.65≦x≦0.8, 0.1≦y+z≦0.2, M represents Ge, AgIn, AuIn, or AgAuIn) as a main component. Further, in the phase-change recording medium of the present invention, an absorptivity Ac of the phase-change recording layer in the crystallization state is set higher than an absorptivity Aa of the phase-change recording layer in the amorphous state.

Abstract: An optical medium uses a single structure or format (such as identical materials, layers and the like) for both a region for holding mastered data and a writeable area. In one aspect, a writeable region of a medium with mastered content is used in connection with paying, collecting or accounting for usage or royalties for proprietary intellectual property embodied in or associated with the content. In one embodiment, the (preferably write-once) writeable area can be used for storing later-written information such as annotations, highlighting, reordering, remixing, modifications, supplements, collections, additions, bookmarks, cross references, hypertext or hyperlinks and the like. Preferably, annotations and similar materials can be associated, by the user, with particular portions or content of the mastered data.

Abstract: To provide a rewritable compact disk having a rewritable area interchangeable with a CD-RW, that is, a RAM area (105), and an area available only for retrieving, that is, a ROM area (104), on the same disk surface, a phase-change recording layer is formed in each of the RAM area and the ROM area, with a wobble groove being made in the RAM area, irradiation is carried out with recording light so that an amorphous mark is formed to record information and information is recorded in the form of a pre-pit string (60) in the ROM area, and further when measured using a wavelength of 770 to 790 nm and an optical pickup whose objective lens numerical aperture is 0.49 to 0.51, a ratio |I1−I2|/|I1−I2|a of values of push pull signals before and after recording in the RAM area is set to be in a range from 1.05 to 2.

Abstract: An optical information recording medium includes a substrate, first information recording layer, and second information recording layer. The first information recording layer includes a recording film, first dielectric film whose complex index has a real part n1, second dielectric film whose complex index has a real part n2, and third dielectric film whose complex index has a real part n3. Relationships n1>n2 and n3>n2 are satisfied.

Abstract: This invention relates to a rewritable optical information recording medium essentially comprising a substrate and a recording layer formed on said substrate, wherein the recording layer has the following composition:

Abstract: An optical information recording medium of this invention includes a substrate, a light incident surface, a first reflecting layer formed between the substrate and the light incident surface, a second reflecting layer formed between the first reflecting layer and the light incident surface and stacked on the first reflecting layer, the second reflecting layer being made of the same material as that of the first reflecting layer, and a phase change optical recording layer formed between the second reflecting layer and the light incident surface, the phase change optical recording layer transiting between a crystal state and an amorphous state when irradiated with a light beam.

Abstract: A phase-change optical information recording medium including a substrate and a recording layer provided on the substrate, the recording layer including a phase-change recording material capable of recording information, reproducing recorded information, and erasing recorded information reversibly with reversible phase changes in the phase-change recording material, with successive formation of a recording mark with a low reflectivity and a length of at least one unit extending in an optical recording scanning direction, and a space with a high reflectivity and a length of at least one unit extending in the optical recording scanning direction, wherein information is recorded by a plurality of signals being recorded in the recording layer, each signal constituting a recording mark area including a recording initiation marking portion with (a) a length of at least two times a minimum length of the recording mark and (b) a width (W1) of at least 1.

Abstract: An optical recording medium comprising a substrate and a phase-change type recording layer which may have at least two phases provided on the substrate, wherein the phase-change type recording layer has a composition represented by the following formula (1) as the main component:

Abstract: An optical disk includes a standard area of a standard recording density provided on an inner peripheral sided and a high density area of a higher recording density provided on an outer peripheral side. In each of the standard area and the high density area, a program area is provided so that an independent program can be recorded in each program area. In one aspect of the invention, an optical disk includes, from the inner preriphery to the outer periphery of the disk, a ROM area for read-only purpsoe, a RAM area in which information can be rewritten and a WO area in which information can be written only once.

Abstract: A phase change optical information recording medium including: a substrate; and a recording layer which is located overlying the substrate and in which marks are to be formed to store information, wherein the substrate includes plural sessions including a first session in which pits are formed and which includes a RAM region including a groove and a wobble signal, and a program memory area in which pits are formed and which includes position information of the first session and does not include disc ID information of the phase change optical information recording medium.

Abstract: A description is given of a rewritable optical data storage medium having a phase-change recording layer on the basis of an alloy of Ga-In-Sb, which composition is situated within the pentagonal area TUVW in a triangular ternary composition diagram. These alloys show an amorphous phase stability of 10 year or more at 30° C. Such a medium is suitable for high speed recording, e.g. at least 30 Mbits/sec, such as DVD+RW, DVD−RW, DVD-RAM, high speed CD-RW, DVR-red and DVR-blue.

Abstract: A phase change optical recording medium is provided wherein the power of the laser beam per unit area required in the initialization is reduced. The optical recording medium has a phase change recording layer satisfying the relations: AI≦8.0%, and CI/AI≧3.0 when the medium is initialized with a light beam having a wavelength &lgr;I, and said recording layer exhibits a reflectivity AI in amorphous region and a reflectivity CI in crystalline region at said wavelength &lgr;I.

Abstract: An optical recording medium includes a crystallizing layer for enhancing the crystallization of a phase change memory layer, an energy storage layer for aiding the state transformations of a phase change memory layer, and/or a modifying element for increasing absorption and contrast at short wavelengths. An optical data storage and retrieval system containing same. Also a light-plasmon coupling lens including an optically transparent substrate having a light incident surface and a light-plasmon coupling surface opposite the light incident surface. The light-plasmon coupling surface including at least a set of circular concentric peaks/valleys which form a Fourier sinusoidal pattern in the radial direction of the circular concentric peaks/valleys. A conformal layer of metal is deposited on the light-plasmon coupling surface of the substrate and has aperture at the center of thereof through which plasmons are transmitted.

Abstract: A phase change optical recording medium includes at least a supporting substrate and a recording layer essentially consisting of AgInSbTe alloy compositions implementing recording and readout steps utilizing changes in reflectivity. The recording medium is characterized by the relation v0≧0.7 vWH, where the critical relative velocity of phase change, v0, defined by the value of v, at which the differential coefficient, −dR(v)/dv, reaches a maximum, when the recording medium moves against an optical unit during the recording steps at a relative velocity, v, ranging from minimum and maximum relative velocities warranted for the recording medium, vWL and vWH, respectively. When the reflectivity is measured with varying erase power PE at the linear relative scanning velocity v0, the reflectivity of the recording layer as a function of erase power, R(PE), preferably has a minimum. The recording layer has an activation energy of deterioration equal to or greater than 1.

Abstract: An optical disk has two sides for recording data and at least one recording area for each side. Each recording area is associated with an attribute which designates whether the corresponding recording area is an area which permits rewriting or an area which does not permit rewriting. Data representing the attribute for the at least one recording area of each side is recorded in a structure management table provided in a predetermined part of the disk of each side. The two sides of the disk have different attributes.

Abstract: The present invention relates to a phase-change optical information recording medium comprising a recording layer which reversibly phase-changes between the crystalline phase and the amorphous phase by irradiation of a light having a recording wavelength of 390 to 430 nm, and a light transmittance thermally controllable layer showing a light transmittance varying according to temperature, in which the light transmittance increases at a rate of 0.2 to 0.7% /10° C.

Abstract: An optical disc and a method of recording essential information in and reproducing the essential information from an optical disc are provided. The optical disc includes a pattern of crystalline and amorphous marks representing the essential information. The essential information recording method includes heating an amorphous recording layer above the temperature of crystallization by radiating a laser beam according to a photoelectrically converted signal, and slowly cooling the heated recording layer to the temperature of crystallization or below to form the pattern of crystalline and amorphous marks.

Abstract: A multi-layered optical disc having its recording unit comprised of plural information recording layers, in which two or more information recording layers are layered on a substrate 0.3 to 1.2 mm in thickness, with the interposition of a transparent layer, to from a recording unit, a light transmitting protective layer is formed on the recording unit to a thickness of 10 to 177 &mgr;m, and in which the light is illuminated from the side of the light transmitting protective layer to effect recording and/or reproduction of information signals. At least one of the information recording layers except the information recording layer formed at a remotest position from the light transmitting protective layer has a phase change material as a recording material.

Abstract: A method for sequential reproducing of a rewritable optical disc including a plurality of sessions, each session having at least one attribute information, the method including the steps of a) reading the attribute information of multiple sessions recorded on an optical disc; and b) determining whether to automatically reproduce subsequent sessions based on the read attribute information. Additional key inputs or selection requests, which are conventionally required to invoke reproduction of sessions subsequent to the selected session, can be avoided when the user wishes to reproduce information (e.g., music) from an optical disk in which data is recorded in different sessions by the user and in which data having the same attributes may occur sporadically.

Abstract: An optical information recording medium includes a plurality of recording layers, a reflectance of at least one of the plurality of the recording layers in a non-initialized state with respect to a light beam for initialization being smaller than a reflectance of the same in an initialized state with respect to the light beam for initialization. The recording layers are initialized by irradiating, among the plurality of recording layers, the recording layer positioned farther from a light beam irradiation side with the light beam prior to irradiating the recording layer positioned closer to the light beam irradiation side, so that the initialized recording layers have no initialization irregularities.

Abstract: A phase change optical recording medium is provided wherein the power of the laser beam per unit area required in the initialization is reduced.

Abstract: The present invention provides an optical information recording medium having excellent characteristics in repetitive recording and a sufficient C/N ratio. The optical information recording medium includes a recording layer containing Ge, Te and Sb and a diffusion preventing layers in contact with the recording layer. A composition ratio of Ge, Te and Sb in the recording layer has numerical values which lie within the range represented by the area ABCDE in a ternary phase diagram of Ge, Te and Sb, where the points A, B, C, D and E are as follows: A (Ge50Te50), B (Ge22.5Sb22.0Te55.5), C (Ge17.0Sb41.5Te41.5), D (Ge48.0Sb26.0Te26.0), E (Ge65Te35) The diffusion layer contains at least one compound selected from an oxide, a nitride, a nitrogen oxide, a carbide and a fluoride.

Abstract: A phase-change optical recording medium capable of implementing record and readout operations of information data through reversible phase transition between amorphous and crystalline states induced by light beam irradiation in a recording layer included in the recording medium, including at least a transparent substrate and contiguous layers formed on the substrate in order as follows, a lower dielectric protective layer, the recording layer, an upper dielectric protective layer, and a reflective/heat dissipating layer, in which the upper dielectric protective layer essentially consists of a mixture of ZrO2 and SiO2, having a composition of (ZrO2)100−x (SiO2)x, where 0<x<60 (mole %).

Abstract: The present invention provides an optical recording medium in which the spot size of incident laser beam, focused on the medium by a far-field optic system characterized by &lgr; and NA, is further reduced and maintained below the diffraction-limited size by means of material characteristics of the medium while reproducing from and recording on the information layer of the recording medium, thus making it possible to record and reproduce a high density of information exceeding the resolution limit of the optic system.

Abstract: A multilevel phase change optical recording medium comprises first to N-th (N≧2) phase change optical recording layers, wherein an i-th recording layer and a j-th recording layer, which are two recording layers arbitrarily selected from the first to N-th recording layers, meet the conditions of Ti>Tmi and &tgr;wi<&tgr;xi, and Tj<Tmj or &tgr;wj>&tgr;xj, with respect to a particular recording laser beam selected from recording laser beams having different power levels, where T is the maximum temperature of the recording layer in a recording operation, Tm is the melting point of the recording layer, Tx is the crystallizing temperature of the recording layer, &tgr;w is a time required for the recording layer to be cooled down from Tm to Tx after the laser beam irradiation, and &tgr;x is the crystallizing time of the recording layer.

Abstract: A multilevel phase change optical recording medium comprises first to N-th (N≧2) phase change optical recording layers, wherein an i-th recording layer and a j-th recording layer, which are two recording layers arbitrarily selected from the first to N-th recording layers, meet the conditions of Ti>Tmi and &tgr;wi<&tgr;xi, and Tj<Tmj or &tgr;wj>&tgr;xj, with respect to a particular recording laser beam selected from recording laser beams having different power levels, where T is the maximum temperature of the recording layer in a recording operation, Tm is the melting point of the recording layer, Tx is the crystallizing temperature of the recording layer, &tgr;w is a time required for the recording layer to be cooled down from Tm to Tx after the laser beam irradiation, and &tgr;x is the crystallizing time of the recording layer.

Abstract: In a phase change optical recording medium, time required for recording the unrecorded area as well as jitter produced are reduced. Provided is an optical recording method for recording an optical recording medium having a phase change recording layer, wherein the recording is conducted such that: VW/Vo>1, and 0.

Abstract: An optical information recording medium includes a substrate for allowing laser light to be transmitted therethrough; a first protective layer for protecting the substrate: a recording layer for allowing information to be recorded thereon by laser light irradiation; a second protective layer for protecting the recording layer: an absorption layer for absorbing heat generated by the laser light, and a reflective layer for reflecting the laser light.

Abstract: An optical disk apparatus for a phase-change optical disk detects the boundary between a first region and a second region prior to detecting a synchronization mark. The synchronization mark is detected in accordance with the position of the detected boundary between the first region and the second region. User data is read from a data region in accordance with the detected synchronization mark.

Abstract: A phase-change optical information recording medium includes, on a transparent substrate, a recording layer in which an optically detectable reversible change between an amorphous phase and a crystalline phase can be caused by irradiation with an energy beam, a reflective layer, and a dielectric layer arranged between the recording layer and the dielectric layer. A main component of the reflective layer is Ag. A main component of the dielectric layer is at least one selected from the group consisting of an oxide of Ta, nitride of Ta and a nitrooxide of Ta. An interface layer may be provided between the recording layer and the dielectric layer. Thus, an optical information recording medium with superior corrosion resistance, improved signal amplitude and high reliability can be provided, as well as a method for manufacturing the same and a method for recording/reproducing the same.

Abstract: A hybrid optical recording disc having a substrate and a recording layer disposed over the substrate, the substrate having a read-only (ROM) area in which a groove is modulated by depressions in the substrate and a recordable area in which the groove from the read-only area extends into the substrate in the recordable area. The groove in the read-only area forming wobbling tracks having a depth greater than 170 nm and wherein the depth d2 of the depression in the groove in the read-only area is in a range greater than 170 nm and less than 350 nm.