Abstract: A conventional mechanical precision measuring device is used effectively in the measurement of the eccentricity of a high density optical disc. A DVR optical disc 2 comprises a pattern 4 of fine depressions and protrusions conformed to the intended format of the disc (a first depressions and protrusions: pits and/or grooves) formed within an information recording area 6 of the disc, as well as a pattern 8 of fine depressions and protrusions for measuring the eccentricity (a second depressions and protrusions), which is formed in an area other than the information recording area 6, and is formed in accordance with a CD format having lower recording density than that of the format defined for the DVR optical disc 2. By using this pattern 8 of fine depressions and protrusions for mechanical detection, conventional mechanical precision measuring devices designed for the CD family can be used as it is, for measuring the eccentricity (mechanical precision) of the DVR optical disc 2.

Abstract: A recording layer (2) and a light-transmitting layer (3) are provided on a substrate (1) having a guide groove for tracking a light beam projected in a spot for information recording/reproduction. The spot light beam is projected onto the recording layer (2) through the light-transmitting layer (3) so as to record information in a first portion (G?) of the recording layer corresponding to the inside (G) of the guide groove and a second portion (L?) of the recording layer corresponding to a flat portion (L) between adjacent guide grooves. The depth d of the first portion (G?) with respect to the second portion (L?) on the light-transmitting layer side of the recording layer (2) satisfies the relation ?/5.8nf?d??/5nf where ? is the wavelength of the light and nf is the index of refraction of the light-transmitting layer (3) to the wavelength ?. The reflectance of the recording layer (2) after the recording is larger than that before the recording.

Abstract: A substrate (1) having a guide groove for tracking with spot irradiation light beam for recording/reproduction of information is provided with a recording layer (2) and a light transmitting layer (3). The recording layer (2) is irradiated with a spot light beam through the light transmitting layer (3) to record information on both a first portion (L?) of the recording layer corresponding to a flat section (L) between adjacent guide grooves and a second portion (G?) of the recording layer corresponding to a guide groove inside (G). Recording marks with mark lengths of nT?mT (where T is a unit length, n, m are integers of one or more, n<m) are formed on the first and second portions (L?, G?). The amplitude IL1 of a reproduced signal from the longest recording mark with the mark length of mT recorded on the first portion (L?) and the amplitude IL2 of a reproduced signal from the longest recording mark with the mark length of mT recorded on the second portion (G?) satisfy the relation 1<(IL1/IL2)<1.3.

Abstract: An optical recording and reproduction medium in which pits corresponding to recording information are formed along a recording track, wherein auxiliary pits are formed in at least a portion of the spaces between adjacent pits along the recording track direction; when the pit depth is d1 and the auxiliary pit depth is d2, then d1?d2 is obtained; and both edges of the auxiliary pits along the recording track direction are shaped as simple convex curves.

Abstract: An optical communication system includes at least one optical ID tag and at least one optical reader. Identification information is communicated between the optical ID tag and the optical reader using light as a communication medium. The optical ID tag includes storing means for storing the identification information; reflecting means for reflecting incident light in the incident direction; and modulating means for modulating reflected light on the basis of the identification information stored in the storing means.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by phase shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: An optical recording method to be used for recording at a high data transfer rate length-modulated marks on a recording medium by applying a recording laser beam locally to the recording medium. The recording laser beam has a writing power Pwi, is and a bias power Pbi. A record mark has a length of nT. With respect to at least two record marks, a pulse dividing number m is at least 2, and with respect to all record marks with m being at least 2, 2.5 is smaller than or equal to n/m, in a case where plural different record mark lengths are to be respectively formed by the same pulse dividing number m.

Abstract: An optical disc has a security feature in the form of an RFID tag that communicates with a voltage controlled optical modifier layer in the optical disc. In the presence of an interrogation signal, the RFID tag allows the optical disc to be used normally by outputting a voltage to the optical modifier layer. In the absence of an interrogation signal, the optical modifier layer prevents a laser from reading from or writing on the optical disc. Other embodiments are also disclosed.

Abstract: In step S1, the address generator generates address information composed of a sync signal which is recorded on an optical disc, address data and an error correction code for the address data, pre-encodes and supplies it to a modulator. At the same time, a carrier signal generator generates a carrier signal which is to carry the address information, and supplies it to the modulator. In step S2, the modulator makes MSK modulation of the carrier signal supplied from the carrier signal generator on the basis of the pre-encoded address information supplied from the address generator, and supplies a resultant MSK modulation signal to a wobbling unit. In step S3, the wobbling unit forms, on the optical disc, a spiral groove wobbled adaptively to the MSK modulation signal supplied from the modulator. In this optical disc, a given address can be accessed quickly and accurately.

Abstract: An optical recording medium has a user data area and a lead-out area, wherein the user data area and the lead-out area each has grooves and lands formed thereon. Wobbles are formed on at least one lateral surface of grooves of the user data area and the lead-out area, and configured such that wobble characteristics are made different between the user data area and the lead-out area. Different types of wobbles are formed on the grooves of either the user data area or the lead-out area, thereby preventing an optical pickup that performs recording/reproduction from deviating from the user data area. Also, in a multi-layer optical recording medium, a whole area of a recording layer is configured to have a same condition, thereby preventing deterioration in reproduction and/or recording due to a difference in light power transmittance of another recording layer.

Abstract: A record carrier has a servo track indicating an information track intended for recording information blocks, which servo track has a variation of a physical parameter, referred to as wobble. The wobble is modulated for encoding record carrier information, such as addresses. The servo track is subdivided in non-modulated and parts modulated parts in which the frequency and/or phase of the variation deviates from the wobble frequency. The slope of the wobble is substantially continuous at transitions between the modulated and non-modulated parts by using wobbles starting at the maxima or minima of the wobble.

Abstract: An optical disk has transparent substrate layer provided at light incidence side, first information layer which has first groove of first depth, adhesive layer provided on the first information layer, and second information layer which has second groove of second depth that is deeper than the first depth, and irreversibly records information therein, wherein the first depth and the second depth are ?/2n or less, the width of the first and second grooves is 0.3 ?m or less, the track pitch of the first and second grooves is 0.45 ?m or less, the first and second information layers include organic dye material having light absorption in the range of the wavelength ? of laser beam for use in recording and reproducing information from 390 nm to 420 nm.

Abstract: An optical information storage medium includes a lead-in area, a lead-out area, and a user data area between the lead-in and lead-out areas and in which user data is recorded. Pits are formed in the lead-in area, the user data area, and the lead-out area, and a track pitch in all or a portion of the lead-in area is different from a track pitch in the remaining area of the optical information storage medium.

Abstract: There is provided an optical information detecting method. The method includes: detecting an image of a source data page coded with balanced codewords by the use of 1:N (where N is greater than 1) excessive detection pixels; determining a distribution pattern of valid detection pixels and invalid detection pixels to be corrected in the detected image by the use of a light intensity distribution of the detected image; and dividing the detected image into balanced codeword detecting areas corresponding to the balanced codewords and sampling data of the balanced codeword detecting areas by the use of the determined distribution pattern and an optical distribution characteristic of the balanced codewords. Accordingly, it is possible to efficiently detect optical information by the use of a 1:N over-sampling method. Specifically, the distribution pattern of valid detection pixels and invalid detection pixels in the detected image of a data page can be properly used to sample a balanced code.

Abstract: An automatic detecting device of land pre-pits signal is disclosed. The device adjusts gain of push-pull signals to raise the signal to noise ratio of the land pre-pits signal to the wobble signal. Digital logic computation is also utilized to recognize the practical position of the land pre-pits. The level automatic detection of the RC circuit and the fixed slice level compose an automatic slice level, which is the basis for detecting the land pre-pits. The disclosed device eliminates the drawback of not easy to obtain correct land pre-pits signal from written disks by the conventional of fixed land pre-pits slice level technology.

Abstract: An optical disk drive for optimizing laser power to be used at the time of recording operation. In a DVD-R drive and a DVD-RW drive, a controller performs OPC to set recording power and records RMD serving as recording management data in an RMA serving as a recording management area. The RMD are verified. When the RMD can be read, the number of PI errors in the RMD is detected. If the number of PI errors is equal to or less than an allowable value, data are recorded in a data area at that recording power. If the number of PI errors exceeds the allowable value, OPC is again performed, to thereby reset the recording power.

Abstract: Hardness of a resin substrate of an optical disc is selected to be greater than hardness of a cover layer of the optical disc, at least when information is recorded on the optical disc. A laser beam is transmitted to an organic dye layer of the optical disc through the cover layer and a protection layer when information is recorded on the optical disc. The organic dye layer is sandwiched by the protection layer and a reflection layer. The substrate has grooves on its surface, and information is recorded between the grooves. The organic dye is heated and expands upon information recording, but a stress generated by the deforming organic dye layer is mainly transferred toward the cover layer. Deformation of the reflection layer and crosswrite upon information recording can be prevented. Therefore, the optical disc can record information between the grooves at a high density.

Abstract: A groove track and a land track are alternately and spirally formed on an information recording medium. On the land track neighboring the groove track, pre-information indicating position information of a track on a disc is formed as a prepit. On the information recording medium, an embossed area is formed so that information about a copyright and for preventing an illegal copy cannot be rewritten. In the embossed area, an embossed configuration including a pit and a space of predetermined depths is formed. The prepit in the embossed area is formed so that the prepit has an optimized configuration according to a pit length and a space length in the embossed area which the prepit neighbors. Consequently, interference between the embossed configuration and the prepit can be prevented even in a case that the prepit is formed in addition to the embossed configuration in the embossed area.

Abstract: Multilayered optical recording media having three or more recording layers used to require spacing between recording layers to be accurately controlled to cope with the effect of crosstalk attributable to multiple reflections at plural recording layers. Making reflectivity at a backside of each recording layer lower than reflectivity at a front side thereof can reduce the effect of multiple reflections without requiring technology for highly accurately controlling interlayer spacing, so that medium production cost can be greatly reduced.

Abstract: A magneto-optical recording medium in which the inside of grooves formed along recording tracks is a signal recording area in groove recording, and the domain wall displacement detection method is employed; and a curvature radius R1, in the cross section perpendicular to the recording tracks, of a shoulder portion of a land separating the grooves that is adjacent to the groove is 30 nm or less and a curvature radius R2, in the cross section perpendicular to the recording tracks, of the inside edge portion of the groove for the recording that is adjacent to the land is 20 nm or more, so that a wide recording power margin can be obtained, the jitter can be improved, and the error rate can also be improved.

Abstract: An optical recording and reproducing medium has grooves formed thereon along recording tracks, this optical recording and reproducing medium being recorded and/or reproduced with irradiation of light having a predetermined wavelength ?. Since the grooves are composed of a first groove 2 and a second groove 3 shallower than the first groove 2 and the second groove 3 is disposed adjacent to both sides of the first groove 2, a recorded signal can be suppressed from crossing the tracks and a sufficiently large amplitude amount of a push-pull signal can be obtained. Thus, an optical recording and reproducing medium can produce a stable tracking signal and hence a recording density can be increased.

Abstract: An optical analysis disc includes grooves defining corresponding laser-readable tracks and trigger marks that identify respective target regions on the disc. The trigger marks are implemented as a radial interruption of the grooves to thereby produce an increased reflection of a laser beam. There is also provided an optical analysis disc system including a trigger mechanism having a trigger detector adapted to detect interruptions in grooves of an optical analysis disc. A related method for triggering through interrupted grooves of an optical analysis disc includes detecting interruption in the grooves, generating an electrical reflection signal corresponding to the interruptions detected, and elaborating said reflection signal, so that to generate a trigger signal.

Abstract: Second digital information serving as copyright protection information can be stably and reliably read without any effect of a defect or pit missing on a disk-shaped recording medium. The second digital information is recorded onto a disk-shaped recording medium by wobbling a pit sequence recorded as a first signal. The second digital information is recorded so that a plurality of bits constituting the second digital information are allocated in a unit period of an identical sync signal contained in the first signal. During playback, the plurality of bits constituting the recorded second digital information are read a plurality of times every unit period of the sync signal, and information of the read bits is then integrated. Thus, information from a large number of wobbled pits across unit periods of a plurality of sync signals can be integrated to determine the bit values.

Abstract: An optical recording medium is provided, which has reduced degradation in jitter caused by manufacturing variations of a semiconductor laser emitting laser beams or variations in output power of laser beams, and which dissipates heat in the recording layer during recording by laser beams to increase the power margin of the laser beam providing playback jitter values at a certain level or less. An optical recording medium 10 has a support substrate 12, on which formed are a reflective film 16, a second dielectric layer 18, a recording layer 20, a first dielectric layer 22, a heat sink layer 24, and a light-transmitting layer 26. The heat sink layer 24 is formed of a material having a thermal conductivity within a certain range, e.g., alumina, to dissipate heat through the heat sink layer 24 when the heat is generated by a laser beam incident from the light-transmitting layer 26, thereby preventing an increase in temperature of the recording layer 20.

Abstract: A method is disclosed to purify a polymeric material by filtering a melt comprising poly(arylene ether) and poly(alkenyl aromatic) through a melt filtration system. The method provides a polymeric material having reduced levels of particulate impurities. The polymeric material prepared is suitable for use in data storage media applications.

Abstract: A high-definition optical disk and a high-definition optical disk drive, which record data on lands and grooves. Wobbles are formed in grooves and lands of an optical disk, and address information is embedded in the wobbles. The wobbles are formed so as to become in phase with each other in the grooves. An address of the land sandwiched between the grooves is detected from the wobble of the groove. When the wobble of the land is not an in-phase wobble but is of opposite phase, a gray code of the wobble is substituted with a binary address such that 0 is achieved when the gray code is converted into the binary address. As a result, even in the case of the wobble of opposite phase, the address information about the land is made coincident with address information about an inner-radius-side adjacent groove, thereby determining address information about the land.

Abstract: An optical recording and reproducing medium has grooves 2 formed along recording tracks and can be recorded and/or reproduced with irradiation of light L having a predetermined wavelength ?. When n assumes a refractive index of a medium extending from a light entrance end face to the grooves 2 of the optical recording and reproducing medium, a phase depth x of this groove 2 satisfies the following inequality: ?/16.14n?x??/4.99n and a ratio w/p between a width w of the groove 2 and a track pitch p satisfies the following inequality: 0.391?(w/p)?0.

Abstract: A recording and reproducing apparatus of the present invention includes a photo-detector having light receiving sections divided along the track direction of an optical disk. The apparatus also includes a wobble signal processing circuit for generating a wobbling polarity judging signal used in judging a wobbling polarity of a track being tracked by comparing phases of a first wobble signal detected from a difference signal of the outputs of the light receiving sections and a second wobble signal detected from a sum signal of the outputs of the light receiving signals. Consequently, whether the wobbled side wall of the track being tracked is the inner or outer radius of track can be judged in real time by a simple structure using one laser beam.

Abstract: An optical information recording medium and a method of mastering an optical information recording medium. Cross-talk is avoided even when phase pits flanking a groove are radially aligned so that preformat information can be reliably reproduced after information is recorded at the grooves. A phase pit that encodes preformat information for a groove is radially spaced from that groove by a partition wall but is connected to an adjacent groove. When mastering, respective first and second exposing light beams are used to form the grooves and the phase pits, and the spacing between the two beams and, therefore, the width of the partition walls in the radial direction is precisely and easily controlled by controlling the inclination angle of at least one of the beams relative to an objective lens in the mastering exposure system.

Abstract: On a magneto-optical disk, a first groove Gv1, a second groove Gv2, and a third groove Gv3 are formed so as to be adjacently arranged. The first groove Gv1 and the second groove Gv2 are deep grooves, and the third groove Gv3 is a shallow groove. The first groove Gv1 and the second groove Gv2 are formed by being wobbled. Data is recorded on four recording tracks of the two deep grooves and two lands between the deep grooves and the shallow groove. A CTS signal is obtained by a sum signal (A+B+C+D) of a photo-detector 6, and a push-pull signal is obtained by a difference signal (A+D)?(B+C) of a photo-detector 8.

Abstract: A method and apparatus for recording information by irradiating light onto a medium to form a recorded domain, and method and apparatus for reproducing the recorded information are provided. In one example of the method, a plurality of light spots are modulated synchronously and irradiated onto a recording medium so that the plurality of light spots have an overlapped region on the recording medium. Since the profile of the total energy of the plurality of light spots is varied when the intensities of the plurality of light spots are modulated synchronously, it is possible to move the position where the total energy becomes maximum to any position on the optical recording medium. Thus, by moving the maximum point of the total energy of light spots in a cross-track direction, information can be recorded in a wobbled manner.

Abstract: An optical information recording medium including a ROM region in which pits are previously formed at a track pitch (P); and a RAM region including a groove which is to be exposed to laser light to form at least one of a pit and a mark therein and to record information to be reproduced, wherein the pits in the ROM region are wobbled in a radius direction of the recording medium, a wobbling inter-pit groove is formed along the wobbled pits, wherein the width (W) of the inter-pit groove is narrower than that of the groove in the RAM region. The ratio (W/P) of the width (W) of the inter-pit groove to the track pitch (P) is preferably from 0.2 to 0.4.

Abstract: On an information record medium (1), information is optically recorded and reproduced while a servo control is performed with respect to the information record medium by a push-pull method. The information record medium is provided with: a record/reproduction area (DA) having a groove track (2), which is wobbled and continuously formed and on which the information is recorded and reproduced by a phase changing method by use of a light beam (B) having a wavelength of not less than 630 nm (nanometer) and not more than 680 nm; and a reproduction-dedicated area (RA) where a plurality of phase pits (PI) are wobbled and formed in advance, each having a depth of not less than 60 nm and not more than 90 nm and where only an information reproduction is possible by the light beam.

Abstract: A recording medium and manufacturing method thereof, the recording medium comprising a control data area in which control data is prerecorded; and an information data area in which information data is to be recorded. The control data has a basic portion and an extension portion. The basic portion has a length corresponding to the information data.

Abstract: A first substrate is formed to include a surface on which a first record layer is formed, and which includes an inner circumferential portion on which a ring-shaped member is provided. Ultraviolet curing resin is dropped onto part of the surface which is located inward of the ring-shaped member, and the first substrate is then spun to coat the first record layer with the ultraviolet curing resin. Furthermore, a second substrate is formed to include a surface on which a second record layer is formed, and the second substrate is spun to coat the second record layer with ultraviolet curing resin. Then, the first and second record layers are made to face each other, and the first and second substrates are bonded to each other by the ultraviolet curing resin.

Abstract: A rewritable type optical disc includes recording tracks formed with break portions; and recording marks corresponding to predetermined data and formed on the recording tracks. The recording marks are formed over the break portions on the recording tracks. If the predetermined data, such as control data, recorded as the recording mark is illegally altered, the position of the recording marks are changed and some break portions are not covered by the recording marks. Since the return light level of the break portion, which is not covered by the recording mark, is different from the return light level of the break portion covered by the recording mark, such illegal alteration of the predetermined data such as the control data may be detected.

Abstract: A writing scheme for writing an information to an optical recording medium by forming mark areas, e.g. pit areas, corresponding to a predetermined state of said information on a recording surface of said optical recording medium. The writing scheme is adapted to modulate the shape of said mark areas in a predetermined manner so as to obtain incomplete mark areas which do not fully cover the size which is allocated to the channel bit to be written. The incomplete mark areas may be obtained by modulating their shape in any manner suitable to reduce the reflection surface and/or to increase diffraction. Additionally, a multi-level modulation or a binary modulation may be achieved by controlling the shape or number of the incomplete mark areas, respectively, in accordance with the level of a multi-level coded information.

Abstract: A rewritable data storage medium has a rewritable recording layer provided with a tracking structure. The recording layer has a data recording area. An erasable identification mark is present in an identification mark area other than the data recording area. The data recording area has a first tracking structure, whereas the identification mark area is substantially free from a tracking structure or has a second tracking structure substantially different from the first tracking structure, such as including concentric or interrupted spiral grooves. Thus erasure of the identification mark is practically impossible, because the location of the erasing spot of a recorder cannot be controlled precisely in radial direction in the identification mark area.

Abstract: An optical data storage medium (20) for recording by means of a focused radiation beam (29) is described. The radiation beam having a wavelength ? enters through an entrance face (28) of the medium during recording. The medium has a substrate (21) with a surface (24) including a guide groove with a depth g. An inverted stack of layers is present on the substrate (21) including a reflective layer (24a) with a complex refractive index ñM?=nM??i*kM?, in substantial conformity with the surface (24) of the substrate, a transparent layer (22) through which the radiation beam (29) is incident with a complex refractive index ñT?=nT??i*kT? and a recording layer (25) of a material having a complex refractive index ñR?=nR??i*kR? and having a thickness dRG in the groove portion and a thickness dRL in the portion between grooves. The recording layer is interposed between the reflective layer (24a) and the transparent layer (22). When 0.25/(3.0+kM?2)+0.17<g*nT/?<0.22/(3.0+kM?2)+0.45 and 0.2<(dRG?dRL)/g<0.

Abstract: An optical disc for storage and retrieval of digital data, and a system and method for protecting the optical disc is disclosed. The optical disc has projections or embossments on one or both surfaces. When the optical disc is placed on a substantially flat surface such as a tabletop or a desktop, the projections act as pedestals that elevate the optical disc above the flat surface. The resulting gap or clearance helps prevent damage to the optical disc caused by contaminants on the flat surface or by defects in the flat surface. The projections are sized to provide adequate clearance between the disc and the flat surface, while minimizing interference between the projections and components of optical disc readers and drives. The optical disc may also include one or more depressions that are sized and configured to receive projections from another disc, which facilitates stacking of the optical discs.

Abstract: A recording and reproducing method for a record medium including the steps of reading type information from the record medium when data is recorded to or reproduced from the record medium on which the type information is recorded; reading type information from a recording and reproducing apparatus for the record medium; comparing the type information read from the record medium with the type information read from the apparatus; and performing a recording or reproducing process for the record medium using information corresponding to the type information stored in the apparatus when the type information read from the record medium matches the type information read from the apparatus.

Abstract: In an information recording medium comprising at least a substrate, a recording layer, and a resin layer, the substrate is formed with at least a pit corresponding to a read only area 31 and a groove corresponding to a recording/reproducing area 32 without overlapping with each other. A reflectivity of the recording layer is specified to be more than 10%. The recording layer and the resin layer are continuously adhered over both the read only and recording/reproducing areas 31 and 32. The information recording medium is characterized in that both push-pull signal outputs T1 and T2, which are reproduced from the read only area 31 and the recording/reproducing area 32 respectively, are more than 0.1 and satisfy an inequality 1.5?T1/T2?0.5.

Abstract: Described herewith is an optical disk manufacturing apparatus for reading recorded digital data from an optical disk, comprising an encryption unit (22, 23) for encrypting entered digital data according to a plurality of key information; an optical disk substrate manufacturing unit 2 for manufacturing an optical disk substrate 4 on which the encrypted digital data and key information are recorded in the form of physical form changes; a reflection film forming unit 41 for forming a reflection film on the optical disk substrate 4; and a key information recording unit 7 for recording key information on the optical disk substrate on which the reflection film is formed. The reflection factor of the optical disk is changed locally, thereby giving a jitter to the position information of each pit edge, and desired data is recorded additionally according to this jitter. Pits, etc.

Abstract: In an optical recording medium including a grooved light-transparent substrate, a phase change recording layer, a dielectric layer and a reflective layer, recording is carried out by irradiating a laser beam to the recording layer through an objective lens in an optical system. The recording is carried out in a groove recording mode under the conditions: 0.48?PT/(?/NA)?0.74, and PT?0.50 ?m wherein ? is a laser beam wavelength, NA is an objective lens numerical aperture, and PT is a track pitch, thereby forming a recorded mark having opposite ends extending out of the groove. This enables high density recording and increases the data transfer rate of a phase change optical recording medium.

Abstract: The present invention provides a method of manufacturing an optical recording medium having two recording layers on a supporting substrate and an optical recording medium obtained according to the method.

Abstract: An optical information-recording medium has a plurality of lands and grooves formed on a substrate. In-groove pits are formed at the bottom of a part of the grooves. The widths of the in-groove pits in the radial direction of the substrate are suppressed from being widened irrelevant to the lengths in the groove direction. Predetermined shapes of the land and the groove are maintained for the shape of the land disposed adjacently to the in-groove pit without greatly eroding or scraping the side wall. A recording signal obtained from land prepits can be reliably detected on the optical information-recording medium manufactured by using the substrate formed with the land prepits disposed adjacently to the in-groove pits.

Abstract: A code disk for a high-resolution encoder that can detect an absolute position and a method for manufacturing a mold to produce the code disk are provided. The code disk is formed by using transparent substrate. The code disk includes a plurality of tracks provided on the transparent substrate and an area provided between the plurality of tracks. Each surface of the plurality of tracks has a different pattern. A level of the area is different from that of the each surface of the plurality of tracks. The method for manufacturing the mold includes steps of processing a plurality of tracks with a flat surface on material; processing an area with a level different from that of each surface, between the plurality of tracks; forming different patterns on the each surface; plating the first material; and peeling plating from the first material to obtain a mold.

Abstract: An optical recording medium of the present invention includes a substrate (202), a protection plate (205), and a plurality of information layers (203) sandwiched between the substrate and the protection plate. An information signal is recorded as a length of a mark and a length of a space between two marks. The mark is formed when the information layer is irradiated by light received through the substrate. The information layers have a management region (206) recording a leading edge recording condition and a trailing edge recording condition. The leading edge recording condition is used to change a recording start position for forming a leading edge of the mark. The trailing edge recording condition is used to change a recording end position for forming a trailing edge of the mark. Each of the leading and trailing edge recording condition is depending on which information layer is recorded.

Abstract: An edge position of a recording pulse is corrected according to multi-valued information for determining the width of a mark in an edge position correction circuit, thereby it is possible to form a mark edge in a correct position when a mark with any width is to be corrected to enable a correct multi-valued recording/reproducing.

Abstract: Improvements in the shape of three-dimensional features displayed in optical recording structures, particularly in such structures displaying features of differing dimensional characteristics. The shape improvements include reductions in berm height and width, dual level data marks and tracking guides, and land areas projecting above or into the surface of the recording structure.