Abstract: Provided are a magnetic recording medium substrate whereupon a magnetic layer can be regularly formed in a recording area, a magnetic recording medium and a method for manufacturing the magnetic recording medium substrate. A plurality of recording areas wherein the magnetic layer is to be formed are formed on the surface of the disk-shaped magnetic recording medium substrate. The size of the recording area is an integral multiple of a lattice constant of a unit lattice of a single crystal structure constituting the magnetic layer. For instance, the width of a protruding section (3) to be used as the recording area is an integral multiple of the lattice constant of the unit lattice of the single crystal structure configuring the magnetic layer.

Abstract: A multi-layered information recording medium including a plurality of recording layers, the multi-layered information recording medium comprising: a user data area for recording user data; and a plurality of spare areas including at least one replacement region, wherein when the user data area includes at least one defect region, the at least one replacement region may be used in place of the at least one defect region, wherein a first spare area of the plurality of spare areas is positioned so as to be contiguous to a first user data area of a first recording layer, a second spare area of the plurality of spare areas is positioned so as to be contiguous to a second user data area of a second recording layer, and the first spare area and the second spare area are positioned approximately at the same radial position on the multi-layered information recording medium.

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 storage medium includes a light transmitting layer, a first information storage layer, an intermediate layer mainly made of resin, a second information storage layer, and a substrate. The light transmitting layer, the first information storage layer, the intermediate layer, the second information storage layer, and the substrate are layered in this order from a reproduction light incident side. Each of the first information storage layer and the second information storage layer includes: a light absorbing film that absorbs reproduction light to generate heat; and a reproduction film that is heated by the heat generated by the light absorbing film so as to reproduce a signal shorter in mark length than a resolution limit of an optical system of a reproducing apparatus.

Abstract: An optical head device according to the present invention includes a splitting section for splitting a light beam having been reflected from an optical storage medium. The splitting section includes: a first main region transmitting a first interfering portion; a second main region transmitting a second interfering portion; and first and second sub-regions through which the first interfering portion is transmitted with a lower rate than in the first main region and through which the second interfering portion is transmitted with a lower rate than in the second main region. The splitting section splits the reflected light beam into: a first main light beam transmitted through the first main region; a second main light beam transmitted through the second main region; a first sub-light beam transmitted through the first sub-region; and a second sub-light beam transmitted through the second sub-region.

Abstract: An optical pickup free from tracking error signal variation when playing back a double-layered disc, and coping with incompatible optical discs, such as BDs and HD DVDs, includes a laser light source, a first polarization rotation element for rotating a polarization direction of an optical beam from the source, an optical branching element disposed in a position after the polarization rotation element to reflect or transmit an optical beam according to polarization of the beam, first and second object lenses for focusing the reflected and transmitted optical beams onto first and second optical discs, respectively, a photodetector for sensing reflected light from the first and second optical discs, and a second polarization rotation element disposed after reflection or transmission of the reflected light from the first and second optical discs conducted by the branching element, to rotate a polarization direction of the reflected light.

Abstract: A recording medium, and a method and apparatus for recording data in the recording medium. The recording medium including an inner area, a data area, and an outer area includes a first test area contained in the inner area, and a second test area contained in the outer area, wherein the first and second test areas are formed by a predetermined wobble modulation method equal to that of the data area. Therefore, the recording medium can be applied to a method for manufacturing a Blu-ray disc, and data can be effectively recorded/reproduced in/from the recording medium, such as the Blu-ray disc.

Abstract: Regarding a signal recorded with a first frequency in a recording area on a specific first recording layer and a signal recorded with a second frequency different from the first frequency in a recording area on a second recording layer which might cause interlayer crosstalk in relation to the first recording layer, a reproducing signal measurement method for a multilayer optical recording medium having at least three recording layers includes reproducing the signal recorded in the recording area on the first recording layer, separating signals recorded respectively with the first and second frequencies, discriminating signal amplitude of the first frequency and a maximum value in signal amplitude of the second frequency, and calculating a signal amplitude ratio between them to measure interlayer crosstalk contained in the signal reproduced from the recording area on the first recording layer. Thus, the interlayer crosstalk quantity caused by unnecessary light can be measured quantitatively.

Abstract: A multilayered optical disk an information recording method and information reproducing method utilizing the disk includes three or more recordable or rewritable information recording layers, which has, among the plurality of information recording layers, at least a first recording layer and a second recording layer located on a side nearer to a light incident surface than the first recording layer, and which respectively has a first test area configured by a plurality of segments in the first recording layer, a second test area configured by a plurality of segments in the second recording layer, and comprising a specific area in which there is recorded information used to determine whether or not the respective segments in the first test area can be used.

Abstract: A servo controlling apparatus of a holographic information recording/reproducing system changes the foci of reference light and signal light in a depth direction of a holographic information storage medium to record information over a plurality of information layers. A servo control is changed from a normal servo operation to a between-movement servo operation while movement between information layers is made during a recording operation, and the servo control is changed back to the normal servo operation when the movement between information layers is completed. The between-movement servo operation maintains a servo control state that exists before the movement between information layers.

Abstract: An information recording and reproducing apparatus records data on and reproduces data from each of a plurality of recording layers of a recording medium. A controller (7) controls a formatting process to format the recording medium (1) by performing a first formatting process on the data area of a recording layer. The first formatting process comprises formatting the data area in a series of recording increments that progress from the inner side of the data area to the outer side of the data area. Within each recording increment the formatting is performed along a path extending from the outer side of the data area to the inner side of the data area. A second formatting process on the data area of another recording layer once the first formatting process has been completed, the second formatting process being performed along a path extending from the inner side of the data area of the other recording layer to the outer side of the data area of the other recording layer.

Abstract: A multilayer optical recording medium having three or more information recording layers is irradiated with a laser beam, and a first signal obtained from the reflected laser beam is subjected to a frequency filter. A second signal obtained by filtration through a high-pass filter is used to evaluate the characteristics of the multilayer optical recording medium. In this manner, even in a multilayer optical recording medium having three or more information recording layers, the influence of the variation of the thickness and material of the information recording layers and the influence of the variation of the thickness of a spacer layer can be clearly determined and evaluated.

Abstract: An optical disc apparatus according to the present invention steadily performs a focus jump operation and a track-crossing seek operation relative to an optical disc having a plurality of recording layers. A signal processing section generates a focus error signal based on a conventional astigmatism detection (CAD) system and a focus error signal based on a differential astigmatism detection (DAD) system from a detection signal generated by an optical detector. When a focus jump is to be performed from one recording layer of the optical disc to another recording layer, a focus drive signal that is generated from the focus error signal based on the CAD system is used. When a read/write operation is to be performed in relation to one recording layer, a focus drive signal that is generated from the focus error signal based on the DAD system is used.

Abstract: An object of the invention is to provide an optical recording medium and an optical information device that enable to improve the quality of a servo signal and a reproduction signal.

Abstract: An additionally recordable information recording medium has a complicated management structure for managing an unrecorded area. Therefore, there are problems that it takes a long time for a disk to startup and it is difficult to build a recording/reproducing system. The additionally recordable information recording medium according to the present invention includes a simple data structure for managing a location information for a recorded area located at the rearmost location in a user data area. An additionally recordable apparatus according to the present invention also includes means for updating the location information of the recorded area so that the recorded area located at the rearmost location in the user data area is always managed.

Abstract: A physical structure, apparatus for recording/reproducing on/from a recording medium using the same and method thereof are disclosed, by which the physical structure suitable for such a recording medium as BD and the like may be provided. The present invention includes a plurality of recording layers. Each of the recording layers includes a power test area not provided to a physically same position and a management area not provided to a physically same position, wherein a layer having the power test zone and the management area allocated consecutively includes a test area buffer allocated to the power test zone.

Abstract: A multi-layered high-density recording medium and an optical power adjusting method therefor. A multi-layered high-density recording medium includes multiple recording layers each of which contains optical power related information for all layers. An optical power adjusting method reading first optical power related information for all layers from a multi-layered optical disk placed in a disk player, storing the read information in another storage device, and making a current optical power apparatus to a moved layer without necessarily having to access the multi-layered optical disk by referring to the stored optical power related information when moving to another layer during record or reproduction.

Abstract: Data is recorded in a phase-change optical storage medium having data layers. A first recording pulse sequence is generated for recording to a first data layer located most remote from a beam-incident surface. The first sequence has a recording pulse carrying an erasing power and a recording power rising from the erasing power, and a cooling pulse carrying a bottom power lower than the erasing power. A second recording pulse sequence is generated for recording to a second data layer. The second sequence has recording pulse carrying an erasing power and a recording power rising from the erasing power, a cooling puse carrying a bottom power lower than the erasing power, and an erasing top pulse carrying an erasing top power higher than the erasing power.

Abstract: To provide an optical head to produce good servo and read signals by reducing the influence of interference by light reflected from a non-read layer of a multilayer optical disc. The head includes: a first optical system for converging light from a light source on a first or second storage layer; a second optical system for receiving and transmitting light reflected from the first layer and stray light reflected from the second layer when the light is converged on the first layer; a photodetector; and a calculator. The photosensitive areas of the photodetector output signals representing intensities of the light incident there through the second system. The reflected and stray light incident on the second system interfere with each other, and the first and second groups of areas are arranged so as to be equally affected by a variation in intensity caused by the interference.

Abstract: Recordable DVD+R and DVD+R/W optical discs with two (or more) information layers are developed to double the data storage capacity and video recording time. A method and device are proposed to make dual layer DVD disc recordings compliant with the dual layer DVD-ROM standard Recording the data in a DVD-ROM compliant way on the dual layer DVD+R or DVD+R/W disc is obtained by shifting the middle zone area towards the inner radius of a disc in such a way that the data zones of both layers are filled up with data.

Abstract: When a hybrid optical disc is loaded on a player, the next generation DVD layer is reproduced in preference to the DVD layer. Jump to the DVD layer is appropriately performed based on the content of the reproduction list held in the next generation DVD. The jump to the DVD layer is performed based on the command information (jump command) held in the reproduction list of the next generation DVD layer. When reproduction of the title specified by the command information is finished after the jump to the DVD layer, the process returns to the HDDVD layer, and reproduction is performed from the position following the reproducing position at the time of the jump. Thus, the content of the HDDVD layer and the content of the DVD layer are reproduced as one stream.

Abstract: A drawing pulse generating unit of an optical disk recording apparatus judges a bit stream of main data contained in a bit stream signal of frame-formatted data, and generates pulse signals DOTX 1 and DOTX 2 based upon the judgment, and then, outputs the generated pulse signals DOTX 1 and DOTX 2 to the gate circuit. In a time period during which a signal level of the pulse signal DOTX 1 is an “H” level, the gate circuit supplies a bit stream signal of the frame-formatted data to a laser driver. In a time period during which a signal level of the pulse signal DOTX 1 is an “L” level, the gate circuit supplies a bit stream signal indicative of an erase level to the laser driver. The laser driver controls an optical pickup so that a laser light having strength indicative of the bit stream signal is irradiated.

Abstract: An optical system for efficiently extracting plural signal beams from a bundle of rays reflected from a multilayer optical disc.

Abstract: On a recording medium, stereoscopic and monoscopic specific areas are located one after another next to a stereoscopic/monoscopic shared area. The stereoscopic/monoscopic shared area is a contiguous area to be accessed both in stereoscopic video playback and monoscopic video playback. The stereoscopic specific area is a contiguous area to be accessed immediately before a long jump occurring in stereoscopic video playback. In both the stereoscopic/monoscopic shared area and the stereoscopic specific area, extents of base-view and dependent-view stream files are arranged in an interleaved manner. The extents on the stereoscopic specific area are next in order after the extents on the stereoscopic/monoscopic shared area. The monoscopic specific area is a contiguous area to be accessed immediately before a long jump occurring in monoscopic video playback. The monoscopic specific area has a copy of the entirety of the extents of the base-view stream file recorded on the stereoscopic specific area.

Abstract: A multilayer optical disk apparatus comprises an optical pickup that emits N (N represents an integer of two or more) laser beams of the same wavelength. The optical pickup emits the N laser beams at the same time, focuses the N laser beams on a first recording layer group alternately configured by N recording layers of the multilayer optical disk and performs a recording operation on the N recording layers at the same time. When changing the recording layers the optical pickup focuses the N laser beams on a second recording layer group configured by recording layers adjacent to the respective recording layers configuring the first recording layer group and performs a recording operation on the N recording layers at the same time.

Abstract: An information recording medium of the present invention is an information recording medium characterized by and including a substrate; and a recording unit capable of recording three-dimensionally a recording pit on the substrate; in which the recording unit has n number of recording layers (n is an integer equal to or larger than 4) and a plurality of intermediate layers laminated with the recording layers one on another; the recording is performed by the condensed recording light using a two photon absorption phenomenon; each of the plurality of intermediate layers is substantially transparent at a wavelength ?1 of the recording light and at a wavelength ?2 of the reproduction light, respectively; the light intensity of the recording light incident into the recording layer nearest to the substrate is more than 0.707 fold as much as the light intensity of the recording light incident into the recording layer farthest from the substrate.

Abstract: An optical recording medium and an optical information device that improve the quality of a servo signal and a reproduction signal. In the optical recording medium, when shape-wise thicknesses tr1, tr2, tr3, and tr4 of a cover layer (42), a first intermediate layer (43), a second intermediate layer (44), and a third intermediate layer (45) are respectively converted into thicknesses t1, t2, t3, and t4 of the respective corresponding layers each having a predetermined refractive index “no”, a defocus amount with respect to a layer having a refractive index nr? and a thickness tr? (satisfying: 1???n (where ? is a positive integer and n is an integer of 4 or more)), and a defocus amount with respect to a layer having the refractive index “no” and a thickness t? (satisfying: 1???n (where ? is a positive integer and n is an integer of 4 or more)) are equal to each other.

Abstract: A photodetector comprising: a first light-receiving surface configured to receive reflected light of zero-order light generated based on a laser beam, from one information recording layer of a multilayer optical disc; a second light-receiving surface that is adjacent to the first light-receiving surface with a predetermined interval, the second light-receiving surface being configured to receive reflected light of diffracted light generated based on the laser beam, from the one information recording layer; and a third light-receiving surface for canceling out reflected light of the zero-order light from other information recording layer of the multilayer optical disc, received by the first light-receiving surface or the second light-receiving surface, the third light-receiving surface being configured to receive the reflected light of the zero-order light from other information recording layer.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: An optical disc apparatus capable of discriminating swiftly and accurately a dual disc from other discs and an optical disc discriminating method, wherein the optical disc apparatus irradiates laser beams having a different wavelength onto the optical disc, detects the reflected light obtained by the irradiation of the laser beams having the individual wavelengths, determines amplitude of an error signal according to the detected results of the individual reflected lights, and discriminates the optical disc based on a ratio of amplitudes of the individual reflected lights.

Abstract: A recording power adjustment process to adjust a recording power is carried out in each recording layer of a multilayered optical disc, and a shift test writing process to adjust the pulse condition of a recording pulse is carried out only with regard to some of the respective recording layers. Then, based on the processing result of the recording power adjustment process and the processing result of the shift test writing process, a processing result of the shift test writing process in each of the recording layers, to which the shift test writing process has not been performed, is predicted. Then, information is recorded on a corresponding recording layer of the multilayered optical disc while adjusting the pulse condition of the recording pulse based on the processing result of the shift test writing process or the prediction result.

Abstract: According to the present invention, a recording film is partially initialized using a first light beam (A) having a wavelength for initialization, focus adjustment is performed using a second light beam (B) having a wavelength corresponding to a wavelength for recording and reproducing information on and from an information recording medium, and then the recording film is initialized using the first light beam (A), thereby it is possible to securely initialize recording films of all information layers of a multilayer information recording medium.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: A method and apparatus for recording information on a multi-layer record carrier includes recording control information in a control information zone before recording user information after a layer jump. This ensures that all user information can be read and recorded reliably, while the storage capacity of the record carrier for storing user information is not reduced.

Abstract: AV stream files and original management files are initially recorded in a first data recordable area of an optical disc. After the recordation of the original management files in the first data recordable area, at least one backup management file is recorded in a second recordable area of the disc. When associated original file system information is recorded in the first data recordable area after the recordation of the backup management file, backup file system information is recorded in a third data recordable area. All of the first, second, and third data recordable areas are closed after the recordation of the backup file system information.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced.

Abstract: It is an object of the present invention to provide an information recording method for recording information in a data rewritable type optical recording medium having a plurality of information recording layers, which can form recording marks having good shapes. In the information recording method according to the present invention, information is recorded in an optical recording medium 10 having at least a stacked L0 layer 20 and L1 layer 30 by projecting a laser beam thereonto whose power is modulated between a plurality of powers including at least a recording power (Pw) and an erasing power (Pe) via a light incidence plane 13a.

Abstract: An optical pick-up to perform recording or reproducing for an optical recording medium is disclosed, which includes a light source configured to emit a light beam, an objective lens configured to focus the light beam onto the optical recording medium, and an aberration generation device provided between the light source and the objective lens, configured to generate coma aberration for the beam focused by the objective lens, based on a detected value from a device configured to detect a degree of tilt of the optical recording medium, wherein the tilt is compensated for by the coma aberration generated by the aberration generation device.

Abstract: An optical recording medium includes a first half-disc and a second half-disc. The first half-disc includes a substrate and an information layer (including a reflective layer) formed on a first side of the substrate. The second half-disc is bonded by an adhesive to a second side of the substrate of the first half-disc. In addition, a cover layer is formed over the first reflective layer. The cover layer has a thickness of approximately 0.1 mm. The substrate of the first half-disc has a thickness in a range of 0.3 mm to 1.0 mm. The first and second half-discs together have a combined thickness in a range of 0.8 mm to 1.3 mm.

Abstract: Provided herein is an optical disc having: an optical plotting layer 17 which is formed at a label surface B-side and on which an image is formed by heat change with a laser beam 28 emitted from a recording surface A-side; a protective layer 18 which is formed at the label surface B-side of the optical plotting layer 17, protects the optical plotting layer 17, and through which the image can be viewed from the label surface B-side; a substrate 15 which supports the protective layer 18 and the optical plotting layer 17; and a guide track 24 which is formed on the optical plotting layer 17 so as to be intermittent in a guide direction.

Abstract: An optical disk compliant with both a conventional optical disk such as a BD, HD DVD, and the like and a next-generation high-density optical disk according to a near-field light recording system and the like is provided. An information recording medium includes a first information recording layer and a second information recording layer, to/from which information is recorded or reproduced using laser beam. The first information recording layer is formed at a laser beam entrance surface, and is configured so that information can be recorded thereupon and/or reproduced therefrom using a first objective lens having a first numerical aperture NA1 and laser beam of a first wavelength ?1. The second information recording layer is formed so as to have a distance to the laser beam entrance surface is 0.05 mm to 1.

Abstract: Performing sequential recording to alternate destinations of an information recording medium and improving access performance of accessing the information recording medium are achieved by estimating sequential defective areas of the information recording medium based on prescribed conditions, allocating blocks of a spare area as alternate destinations of the defective areas, and performing alternate recording to the allocated alternate destinations, in response to a recording request to record information to the sequential defective areas. The above can be achieved because the use of the alternate destinations will help to prevent a time-out from occurring due to he the defective areas.

Abstract: A recording apparatus with a device for recording information onto a medium, provided with: (i) a first layer irradiated with laser light to record information on a first area; and (ii) a second layer irradiated with laser light through the first layer and having a second area whose edge on an inner circumferential side corresponds to an edge on an outer circumferential side of the first area; and a controlling device for controlling the recording device to pre-record, into an area portion of the first area, other than an area portion having a size corresponding to a tolerance length, which indicates an acceptable range of a relative position shift between an address defined on the predetermined position in the first layer and an address related to the predetermined position in the second layer, with the edge on the outer circumferential side of the first area as a starting point.

Abstract: An optical pickup device radiates laser light to a disc having a plurality of recording layers in a direction of lamination. The optical pickup device includes an astigmatic element and a spectral element. The astigmatic element allows reflected light from the disc to converge in a first direction and form a first focal line at a first position, and allows reflected light to converge in a second direction and form a second focal line at a second position closer to the disc than the first position. The spectral element splits a reflected light flux in two along a straight line parallel to the first direction and turns traveling directions of the split two light fluxes into directions separated from each other. Here, the spectral element is interposed between the second focal line of the reflected light from a target recording layer and the second focal line of the reflected light from a deeper recording layer than the target recording layer.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: An information recording apparatus is for recording user data and recording management data onto an information recording medium being provided with: a first recording layer; and a second recording layer, each of the first recording layer and the second recording layer having a user data area to record therein at least the user data and a recording management area to record therein at least the recording management data for managing recording of the user data, the information recording apparatus is provided with: a recording device for dividing the recording management area into a plurality of recording management segments and for recording the recording management data into at least one of the plurality of recording management segments; and a first controlling device for controlling the recording device to dispose each of the plurality of recording management segments in a single recording layer.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: A holographic recording apparatus is provided and includes: a signal light generation section that generates signal light modulated according to digital data; a reference light generation section that generates reference light modulated by means of a pixel pitch; a adding section that adds, in proximity to a light-convergence position where the signal light and the reference light come close to each other or overlap each other, a low-order component of the signal light obtained by Fourier transform and a high-order component of the reference light obtained by Fourier transform, the high-order component of the reference light having a spatial frequency region differing from that of the low-order component of the signal light; and an illumination optical system that irradiate an optical recording medium with the added signal and reference light.

Abstract: A method of recording data in a multilayered recordable optical recording medium is disclosed. When test recording is executed in a multilayered recordable optical recording medium having N recording layers (N is an integer of 2 or more), a test recording range in a test recording area of an (m+1)th recording layer is shifted relative to a test recording range in a test recording area of an mth recording layer by an amount greater than a difference of decentration amounts between the mth and the (m+1)th recording layers or a maximum decentration amount in the N recording layers. The shifting direction is inverse to a test recording range adding direction in a radius direction of the recording medium.

Abstract: An information recording apparatus and method can prevent an information recording medium having a plurality of recording layers from being incompatible with a reproduction-only information recording medium due to an unrecorded area, which is produced by completion of recording in a middle of a data area of the recording layer. The recording layers include at least a first recording layer and a second recording layer, the first recording layer providing a reference with respect to a position of said data area in each of the recording layers. The user data is recorded in response to a recording request. After recording the user data, predetermined data is recorded in a predetermined unrecorded area in the second recording layer.