Abstract: On an optical disk medium according to the present invention, address information is recorded along a wobbling track groove 2. The track groove 2 is made up of a plurality of unit sections 22, 23. Each of these unit sections 22, 23 has side faces that are displaced periodically in a disk radial direction. This displacement oscillates at a single period in a tracking direction. However, the displacement pattern differs depending on “each bit of address information (subdivided information)” allocated to each of the unit sections 22, 23.

Abstract: A second layer is a recording-enabled layer (15) where content data can be additionally written or rewritten and a first layer is reproduction-dedicated layer (14) where no wobble is formed.

Abstract: An improved light-readable information recording medium is provided that comprises an optical data storage structure having lands and pits, in which the depth of the pits is about: ? 2 ? n ? m 1 + M T 2 , wherein ? is the wavelength of light used to read the information recording medium, m is the order of interference selected from a group consisting of odd integers, MT is the transverse magnification, and n is the refractive index encountered by the reading light inside the pits. The invention also provides an improved optical reading system with the parameters satisfying the relationship: nd = ? 2 ? n ? m 1 + M T 2 , wherein ? is the wavelength of light used to read the information recording medium, m is the order of interference selected from a group consisting of odd integers, MT is the transverse magnification, n is the refractive index encountered by the reading light inside the pits, and d is the depth of the pits.

Abstract: A recording medium includes a substrate having a microscopic pattern, which includes a shape of continuous substance of approximately parallel grooves formed with a convex shaped section and a concave shaped section alternating on a surface of the substrate. A recording layer is formed on the microscopic pattern and a light transmitting layer has a thickness of 0.05 mm to 0.12 mm formed on the recording layer. The microscopic pattern satisfies a relation of P??/NA, wherein P is a pitch of the convex shaped section, ? is a wavelength of a reproducing light beam and NA is a numerical aperture of an objective lens. The microscopic pattern also includes modulated address information formed on both side walls of the convex shaped section viewed from the light transmitting layer as a wobble, both the side walls being parallel to each other, and furthermore wherein the address information is modulated by the phase-shift keying modulation system.

Abstract: Provided are an optical disk drive and a disk format necessary for the optical disk, which are capable of eliminating or reducing a problem of reduction in an effective transfer rate attributable to track jumps caused at a certain interval when performing recording and reproduction of multiple tracks in parallel by using multiple beams, and thereby achieving a high transfer rate. A block constituting a recording unit is divided into sub-blocks, and the sub-blocks are arranged in a radial direction of a disk. Meanwhile, an optical disk drive includes a means for irradiating a disk with multiple light spots, a means for pulse modulating the spots by using the same frequency and different phases, and a means for receiving light from the spots reflected by the disk by using a single photodetector, and separating the reflected light into independent lines of signals in terms of a time domain.

Abstract: A memory that includes a controller and a media including first information is provided. A first read/write mechanism is provided including an electron emitter configured to read the first information. The controller is configured to receive a first signal generated in response to the first information being read and generate a second signal configured to cause a position of the media to be adjusted relative to the electron field emitter in response to the first signal.

Abstract: The invention provides an optical disk that enables high-speed reproduction of address signals. A wobble address system for optical disk supports various types of synchronization, such as phase synchronization, bit synchronization, word synchronization, etc., to be established easily with high detection reliability with the use of an self-orthogonal code. Thus, the invention provides a method for easily synchronizing an address signal, i.e., high-speed reproduction of the address signal. Further, by virtue of an efficient modulation system of the address signal and redundancy thereof, it becomes possible to detect address information with high reliability. This capability is particularly effective in optical recording/reproduction with a blue light source whose signal light quantity and reproduction quality are prone to reduce.

Abstract: Disclosed is an optical disk barcode forming method wherein, as information to be barcoded, position information for piracy prevention, which is a form of ID, is coded as a barcode and is recorded by laser trimming on a reflective film in a PCA area of an optical disk. When playing back the thus manufactured optical disk on a reproduction apparatus, the barcode data can be played back using the same optical pickup.

Abstract: According to one embodiment, an information recording medium includes a transparent resin substrate having concentric grooves and concentric lands or a spiral groove and spiral land, and a recording layer formed on the groove and land, and capable of recording and reproducing information by using a semiconductor laser of 450 nm or less. When reproducing recorded information, the information recording medium satisfies the following formula (1) 0.87?M4×/M1×?1.

Abstract: A method for writing a signal on an optical disk is disclosed. The optical disk comprises a track groove on a recording surface thereof, on which information is recorded along the track groove on a block-by-block basis each said block having a predetermined length and where an identification mark indicating the beginning of each said block, has been formed on the track groove. Writing is started before the identification mark, located at the beginning of at least one block on which the signal should be written, is reached and writing is ended after the identification mark located at the end of the at least one block on which the signal should be written has been passed.

Abstract: An apparatus and method to modulate address data of a disc type recording medium, include generating the address data, performing error correction coding of the address data and outputting coded address data, receiving the coded address data in a unit of at least two bits, generating a first modulated signal of the coded address data using a first modulation technique, generating a second modulated signal of the coded address data using a second modulating signal, and generating a unit wobble signal by synthesizing the first and second modulated signals.

Abstract: At the stage where disc substrates are to be manufactured in mass production by using a stamper, a section where pits/lands are not formed is formed in advance as an additional information recording section among recording tracks formed by a recording data sequence of pits/lands. A metal alloy reflection film is coated on the information recording surface including such an additional information recording section 10. Then, thereafter, additional information is recorded in the additional information recording section 10 by forming hole marks 6 by erasing or decreasing a partial area of the metal alloy reflection film. The additional information is recorded in a partial area of recording tracks in the information recording area (the area where information is recorded by a recording data sequence of pits/lands, the area including a content area and a management area such as a lead-in).

Abstract: An optical information recording medium is provided. This medium at least stores information that indicates a maximum recording linear velocity Vh. The medium comprises a substrate having a concentric circular guide groove. This guide grove has land portions and groves portions. At least a phase change type recording layer is formed on the substrate. The recording layer has such a composition and thickness that a dislocation linear velocity V satisfies the relation V?Vh×0.85.

Abstract: It is an object of the present invention to provide an optical recording disc which can record data constituted by a recording mark train including recording marks and blank regions neighboring recording marks therein and reproduce the data therefrom in a desired manner even in the case where the lengths of a recording mark and a blank region between neighboring recording marks are shorter than the resolution limit and whose storage capacity can be markedly increased. An optical recording disc is constituted so that data are recorded therein and data are reproduced therefrom with the irradiation with a laser beam and includes a laminated body formed by laminating a decomposition reaction layer 5 containing platinum oxide as a primary component and a light absorbing layer 7 so as to sandwich a second dielectric layer 6.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: An optical recording medium includes a main-information area in which a metal reflection film is formed on a substrate where a row of pits is formed as main data, and a sub-information area in which is recorded medium identification information, which is used to identify the optical recording medium individually, by removing the metal reflection film partially and forming a plurality of reflection-film removed areas. Information is reproduced by irradiating the metal reflection film with a beam of light. In the sub-information area, a row of pits or a guide groove is formed on the substrate, and a track pitch of the row of pits or the guide groove is at least 0.24 ?m wide and at most 0.45 ?m wide.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: An optical disk includes a first area on which user information is recorded, and a second area in which a plurality of marks radially extending are arranged in a track direction in the optical disk. Information about the reflectance of the optical disk is recorded in the second area. It is intended to optimize the amplification factor of the reproduced signal on the basis of the information about the reflectance of the optical disk in the second area. Control data and user data can be reproduced quickly and highly reliably without depending on the relationship between the reflectances of a recording area and a non-recorded area of the optical disk.

Abstract: An information recording carrier according to one embodiment has minute pattern including plural grooves or lands formed to be substantially in parallel and adjacent each other and comprises a supporting body having the minute pattern, a recording layer formed on the minute pattern formed on the supporting body and a light transmission layer formed on the recording layer. The minute pattern is formed under a relation of P<?/NA, where a pitch of each groove or land is P, a wavelength of a laser beam is ? and a numerical aperture of an objective lens is NA. The plural grooves or lands have at least a wobbling region and data is recorded wobblingly in the wobbling region by frequency shift modulation. A phase relation between a high frequency portion and a low frequency portion composing the frequency shift modulation is ±(?/20.5) to ±(?/0.751).

Abstract: Methods, systems and computer program products for causing recordable DVD storage media to be identified as non-recordable DVD storage media by a DVD drive are described. Data used to identify a recordable DVD storage media (100) as being recordable is occluded (step 190) to prevent correct retrieval from the recordable DVD storage media by the DVD drive. As a consequence, the DVD drive incorrectly identifies the recordable DVD storage media (100) as non-recordable DVD storage media.

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 frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: An information-recording medium having a substrate and a recording part formed on the substrate allowing three-dimensional formation of recording pits, the recording part, comprising multiple recording layers, in which the recording pits are formed with a converged recording light at a wavelength of ?2 and reproduced with a converged reproducing light with a wavelength ?1 shorter than the wavelength ?2, and intermediate layers alternately laminated between the recording layers, wherein the reflectance at the recording light wavelength of ?2 in the unrecorded region is smaller than the reflectance at the reproducing light wavelength of ?1 in the unrecorded regions of the recording layers.

Abstract: The present invention relates to a method of recording secondary information on a record carrier, in particular on an optical record carrier, besides its content information, whereby it is possible to differentiate the record carrier from other record carrier bearing the same content information, for example by recording an individual identifier. The secondary information is recorded by: forming at predetermined positions dummy patterns (23), preferably at the same moment as when recording the content information, and recording the secondary information by selectively modifying the dummy patterns, thereby obtaining modified dummy patterns (24), wherein the dummy patterns as well as the modified dummy patterns correspond to valid channel words. The invention further relates to an apparatus for recording secondary information, to a record carrier, and to a method and to an apparatus for reproducing the secondary information.

Abstract: An optical disc is manufactured under a uniform condition by forming grooves and lands on the entire surface of the disc. The optical disc is configured to obtain a reliable reproduction signal, and the grooves and lands are formed on a lead-in area, a user data area and a lead-out area of the optical disc. Since the same manufacturing condition can be adopted in mastering discs, the yield can be enhanced and the manufacturing cost can be reduced.

Abstract: An optical recording medium and a method for manufacturing the same, which offer to an information layer formed on a spacer layer the same electric characteristics such as a jitter and a noise as those of an information layer formed on a substrate, are provided. A convexo-concave pattern is transferred to a face of a spacer layer, which is opposite to the side of a substrate, so that a radial width of a convex portion is limited to be 53% or larger and 72% or smaller with respect to a radial pitch of concavity and convexity. A second information layer (information layer on the spacer layer) is formed in accordance with the convexo-concave pattern.

Abstract: An optical recording medium has spirally or concentrically formed tracks and capable of an optical recording. The optical recording medium includes a data recording and reproducing area divided into a plurality of zones in the radial direction. One zone is divided into a plurality of sectors respectively having an address area including pits having address information and a data are in which data is only present in grooves. The number of sectors forming each zone is different. An optical disc is formed so that an average reflectance Iadd of the address part and an average reflectance Idata of the data part satisfy a relation expressed by 0.7?(Iadd/Idata)?1.3 or 0.8?(Iadd/Idata)?1.2.

Abstract: In an optical disk including at least a rewritable phase change material and comprising a recording layer having a reflectivity of more than 15%, an address output value as an address pit signal component occupying in a reproduced signal in a non recording state is prescribed to be 0.18 though 0.27 or a numerical aperture of an address pit signal occupying in a reproduced signal in a non recording state is prescribed to be more than 0.3.

Abstract: Provided is an optical information recording medium that can be recorded with data with only a special recording apparatus and the recorded data can be read out with a general recording/reproducing apparatus. The optical information recording medium includes a disc-like light-transmissive substrate having a surface provided with a spiral groove WB having a wobble and a land LN between adjacent segments of the groove WB, a light-absorbing layer disposed on the surface of the light-transmissive substrate, and a light reflection layer disposed on the light-absorbing layer. The groove WB has a depth Ds of about 140 nm?Ds?155 nm, the light-absorbing layer has a recess with a depth Dd of about 95 nm?Dd?105 nm in the groove, and a push-pull signal before recording has a value of about 0.3 or less. The optical information recording medium may include an anti-illegal copy measure.

Abstract: In an optical disk including at least a rewritable phase change material and comprising a recording layer having a reflectivity of more than 15%, an address output value as an address pit signal component occupying in a reproduced signal in a non recording state is prescribed to be 0.18 though 0.27 or a numerical aperture of an address pit signal occupying in a reproduced signal in a non recording state is prescribed to be more than 0.3.

Abstract: A super resolution information storage medium capable of reproducing information recorded thereon as a mark with a size less than the resolution limit of an incident light beam, includes marks of varying sizes recorded thereon, excluding marks with a size in the vicinity of the resolution limit, where the resolution limit depends on the wavelength of a light source irradiating light on the information storage medium and the numerical aperture of an object lens focusing the light irradiated from the light source on the information storage medium. By adjusting the size of or excluding a mark with a size in the vicinity of the limit of the resolution that has a low C/N ratio, the C/N ratio is improved and the performance of super resolution information reproduction is improved such that high density and high capacity information storage medium can be implemented.

Abstract: A recording medium, such as a high-density and/or read-only recording medium, such as BD-ROM, which includes an identification information, which can identify whether optional information, such as copy protection information, is needed or not for the playback of contents stored on the recording medium, and to methods and apparatuses for forming, recording, and reproducing data on the recording medium.

Abstract: The present invention relates to a method and to an apparatus for manufacturing a record carrier having stored a content information in the form of a modulated bitstream 29 obtained from the content information by steps of encoding 21 and modulating 26. The record carrier has a number of dummy patterns at predetermined locations, allowing for the post-recording of secondary information, e.g. an individual code, whereby the secondary information is recorded by selectively modifying the dummy patterns. The method and apparatus according to the invention foresee that the modulated bitstream 29 with dummy patterns at the predetermined positions id obtained by inserting data word corresponding to the dummy patterns in a sequence of data words before the modulation takes place, so as to make sure that the dummy patterns are compliant with the modulation employed.

Abstract: A visible image forming method is performed for forming a visible image on an optical disk by an optical disk recording apparatus, which is designed for applying a laser beam onto an optical disk according to first recording data of a predetermined format to form pits having lengths specified by the first recording data. First, a generating step is performed for generating second recording data by embedding image formation data of a visible image in a part of a predetermined format which is the same as predetermined for the first recording data. Second, an extracting step is performed for extracting the image formation data of the visible image from the second recording data of the predetermined format. Then, a forming step is performed for forming pits in the optical disk according to the extracted image formation data so as to form the visible image on the optical disk.

Abstract: A processor-readable medium comprises processor-executable instructions. The instructions are configured for scanning a reference pattern on a disc to determine a first radial position of the laser, wherein the reference pattern is located at a first nominal distance from a center of the disc and extends to a second nominal distance from the center of the disc, wherein the first and second nominal distances are accurate to within a nominal runout tolerance. The instructions are also configured for reading media ID data on the disc only when the radial position is greater than or equal to the first nominal distance plus the nominal runout tolerance and is less than or equal to the second nominal distance minus the nominal runout tolerance.

Abstract: Data is recorded on an optical disc using a combination of a user data area where user data is recorded, a control data area for reproduction provided on an inner radius side of the user data area, and an outer guard zone provided on an outer radius side of the user data area as a unit of one recording operation. In this configuration, a track pitch TP of the optical disc is greater than or equal to 0.3 ?m and smaller than or equal to 0.4 ?m, and the width of the outer guard zone along a radius direction of the optical disc is greater than or equal to a value of (100×TP) and smaller than or equal to a value of (125×TP).

Abstract: A recording medium includes a substrate having a microscopic pattern, which includes a shape of continuous substance of approximately parallel grooves formed with a convex shaped section and a concave shaped section alternating on a surface of the substrate. A recording layer is formed on the microscopic pattern and a light transmitting layer has a thickness of 0.05 mm to 0.12 mm formed on the recording layer. The microscopic pattern satisfies a relation of P??/NA, wherein P is a pitch of the convex shaped section, ? is a wavelength of a reproducing light beam and NA is a numerical aperture of an objective lens. The microscopic pattern also includes modulated address information formed on both side walls of the convex shaped section viewed from the light transmitting layer as a wobble, both the side walls being parallel to each other, and furthermore wherein the address information is modulated by the phase-shift keying modulation system.

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 frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: There is provided an optical disc having preformed thereon a spiral wobbled track as a grove and/or land along with data is to be recorded. The track is wobbled for a series of predetermined signal units each composed of an FSK information bit part based on a waveform resulted from FSK modulation of information bit and a singe-frequency part based on a waveform of a single frequency. The FSK modulation uses two different frequencies of which the one is the same as the single frequency and the other is different from the single frequency. These different frequencies are in such a relation that each of them has an even number of wobbles and an odd number of wobbles alternately in a predetermined cycle.

Abstract: An optical disc recording medium is irradiated with laser light having a predetermined laser power to deform an irradiated portion of a substrate into a protruding portion. Since the substrate is deformed so as to have protruding portions, a reflecting layer arranged on the substrate is also deformed so as to have protruding portions. For a pit, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each land. For a land, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each pit. Since the deformed state of each protruding portion can be controlled on the basis of the power of the laser light for irradiation, pit-to-land deformation and land-to-pit deformation can be performed by setting the laser power. Thus, recorded data can be rewritten on the optical disc recording medium recorded with the data using a combination of pits and lands formed in the substrate.

Abstract: An information recording medium (100) is provided with: a recording track (GT), which is wobbled, on which information is recorded by forming a recording pit row thereon, the recording pit row is formed to be wobbled in an opposite phase to a phase of the wobbling of the recording track.

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: 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 information recording medium 1 at least comprises a substrate 13 having a microscopic pattern 20, which is constituted by a shape of continuous substance of approximately parallel grooves formed with a groove section G and a land section L alternately, a recording layer 12 formed on the microscopic pattern 20 and a light transmission layer 11 formed on the recording layer. The microscopic pattern 20 is formed so as to satisfy a relation of P<?<NA and a thickness of the light transmission layer 11 is within a range of 0.07 to 0.12 mm, wherein P is a pitch of the groove section G or the land section L, ? is a wavelength of reproducing light beam and NA is a numerical aperture of an objective lens. Further, there provided an information recording medium, which is improved in cross erase and recorded in high density, and a reproducing apparatus and a recording apparatus for the information recording medium.

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 information recording medium 1 at least comprises a substrate 13 having a microscopic pattern 20, which is constituted by a shape of continuous substance of approximately parallel grooves formed with a groove section G and a land section L alternately, a recording layer 12 formed on the microscopic pattern 20 and a light transmission layer 11 formed on the recording layer. The microscopic pattern 20 is formed so as to satisfy a relation of P<?<NA and a thickness of the light transmission layer 11 is within a range of 0.07 to 0.12 mm, wherein P is a pitch of the groove section G or the land section L, ? is a wavelength of reproducing light beam and NA is a numerical aperture of an objective lens. Further, there provided an information recording medium, which is improved in cross erase and recorded in high density, and a reproducing apparatus and a recording apparatus for the information recording medium.

Abstract: There is provided an optical disk which adopts a PRML (Partial Response and Maximum Likelihood) method for reproduction of recorded information and whose shortest pit has a conical shape without a bottom surface. If the PRML method is adopted, since it is not necessary to assure a large amplitude of a reproduction waveform of the shortest pit, the pit may have a conical shape. The conical pit enables recording with the dense shortest pit even in a conventional original disk recorder and original disk exposure process, thereby increasing a recording density in a dividing direction.

Abstract: The present invention relates to an optical recording medium having at least two information carrier layers, on which information can be written by means of a focused light beam. In this case, a separating layer is arranged between the information carrier layers and a respective transparent covering layer is arranged between the information carrier layer and the surface of the recording medium, the thickness of which covering layer substantially exceeds that of the information carrier layer. One object of the present invention is to propose an optical recording medium in the case of which it is possible to write to both information carrier layers using a low optical power. Further objects of the invention are to specify an apparatus and also a suitable method for writing to a recording medium of this type. A recording medium according to the invention has information carrier layers which are both semi-transparent.

Abstract: In an optical disk, a substrate has main data recorded in the form of a combination of pits and lands on one side thereof, and at least a reflective layer and cover layer are stacked on the substrate to cover the pits and lands on the substrate. To the optical disk, sub data is recorded in the form of marks formed by irradiating writing-power laser light to the reflective layer. The marks are formed so that reading signal level will be raised where the marks are formed while it will be lowered where the marks are formed in a counterfeit disk produced based on an authenticated disk, namely, the reading signal level where the marks are formed is different in polarity between in the authenticated and counterfeit disks. Further, in a player for the optical disk, discrimination is made between the authenticated and counterfeit disks by detecting the sub data recorded in the optical disk and judging whether the value of the detected sub data has been read at a correct polarity.

Abstract: An optical disc having marks for dispersed addresses that can be easily detected with high precision. A dispersed address comprises synchronization marks, positive marks, and negative marks. Synchronization marks, positive marks, and negative marks are formed along a groove as partial discontinuities or partial modifications in the wobbled groove.