Abstract: In accordance with the teachings of the present invention, a thin optical disc having remote reading capability is provided. In accordance with a particular embodiment of the present invention, the optical disc includes a central clamping area that defines a central aperture operable to be engaged by a spindle mechanism of an optical disc drive, an optically-readable data storage area substantially surrounding the central clamping area, the optically-readable data storage area having a planar thickness of less than 1.20 mm, and an electronic tag coupled to or embedded within the optical disc, the electronic tag comprising a radio frequency tag or radio frequency identification tag.

Abstract: Information carrier, comprising a disc (101) which is provided with at least one data layer (102) for optically reading and/or writing information, wherein the disc comprises an annular clamping part (C), to be held by a clamper (121) during use, wherein the disc comprises at least one integrated circuit (103), wherein said integrated circuit comprises a first communicator (104) for communication with at least a second, external, communicator (111) during use, wherein the first communicator extends in a centre area (T) which is enclosed by said annular clamping part.

Abstract: An optical disc includes a base having a signal reading surface at a first surface; a reflective layer provided on the signal reading surface of the base; a cover layer provided on the reflective layer; and a small memory device having a communication function provided at a side opposing the signal reading surface of the base.

Abstract: A radio frequency identification (RFID) system for discs such as CDs, DVDs or minidiscs includes a special RFID transponder and antenna configuration. The discs normally include an outer metallized annular zone where information is stored, a central hole, and an inner annular zone between the hole and the outer annular zone. The transponder may be located in the inner annular zone, with antenna elements coupled to the transponder extending in opposite directions part way across the outer annular zone. Multilayer labels with a recess for the transponder chip, and antenna elements formed by conductive material may be employed to apply the RFID assembly to the discs. A monopole or dipole mode of antenna operation, prominently involving the metallized disc layer, results from the antenna configuration, and serves to more than double the range of the system.

Abstract: An object of the present invention is to provide a disk structure and a disk-structure manufacturing method that are capable of preventing the degradation of a signal-to-noise ratio resulting from the occurrence of an eddy current. On a disk 101, a thin film of metal 102, a magnetic thin film 103, and an insulating film 104 are formed in this order, and on the insulating film 104, an RF-ID chip 106 and components of an antenna 109 connected to the RF-ID chip 106 are formed.

Abstract: A secure optical data disc comprising an electronic article surveillance tag embedded within a layered disc structure comprising first and second substrates is disclosed. The tag is placed within a non-readable zone (i.e., one that does not have data tracks) of the secure disc. Layer-wise, the tag is either sandwiched between the two substrates or alternatively embedded within one of the two substrates. In the case where the tag is sandwiched between first and second substrates, a bonding layer occupies a space radially outward from the tag. The bonding layer holds the first and second substrates together thereby forming the secure disc.

Abstract: A rectangular image to be imaged on a flat curved surface is received. The rectangular image is converted to a curved image corresponding to the flat curved surface. The curved image is halftoned. The curved image as halftoned is imaged on the flat curved surface.

Abstract: A data storage cartridge includes a housing, a non-tape storage medium contained within the housing, and a stacking feature provided on a top surface of the housing and on a bottom surface of the housing opposite the top surface. The stacking feature is asymmetrical about a first median axis oriented substantially perpendicular to the top surface and the bottom surface of the housing, and asymmetrical about a second median axis oriented substantially perpendicular to a first end of the housing and a second end of the housing opposite the first end. The stacking feature is configured to facilitate positioning of and maintaining a stacked configuration of the data storage cartridge with another data storage cartridge.

Abstract: A universal low cost radio frequency identification (RFID) tag for use with data storage discs includes an RFID chip, e.g., 2.45 GHz mu-RFID chip, coupled to a linear dipole antenna. The antenna length is reduced in length from the expected length for an optimally tuned antenna corresponding to the operating radio frequency of the RFID chip in a free space environment. The antenna is placed in the tag such as to substantially overlap disc hub area and not extend into data area. The combination of the shortened linear dipole antenna and metallization on the disc to which the tag is applied effectively form a complex antenna operational in the RFID chip's frequency range. The RFID tag works on CDs and DVDs with and without substantially metallized hub areas. The RFID tag is less 0.3 mm thick and may include: ring shape, adhesive material, spacing material achieving uniform thickness, a counterbalance provision.

Abstract: A compact disc (10) for a computer incorporates a security device for preventing non-authorized reading of data carried by the disc. The security device includes an LCD laser blocker (16) which is activated or deactivated by means of a microchip (13) powered by a cell (14) and/or solar panel (15). Authorized reading of the data is possible by a fingerprint scanner (12) linked to the microchip and causing it to deactivate the blocker (16), when the scanner recognizes a user's fingerprint which the microchip matches to a programmed authorized fingerprint. Also disclosed is a data carrying compact disc (20) which incorporates security means to allow a first reading of the data of the disc, but to prevent such reading thereafter. An area (21) of the disc, such as a FAT file, can be arranged to be destroyed or blocked, to prevent subsequent reading thereof by the disc reading means.

Abstract: Embodiments of methods and systems for controlling access to information stored on memory or data storage devices are disclosed. In various embodiments, fluid-mediated modification of information or access to information is utilized. According to various embodiments, data storage devices designed for rotating access are described which include rotation-activated fluid control mechanisms.

Abstract: An information recording medium capable of displaying multiple labels and a storing case for the information recording medium are provided. The multiple labels are displayed by changing the labels to be displayed while selectively selecting information layers in a multi information recording medium. The medium has a function to receive either voltage or current, and the information layers selectively receive either voltage or current for changing the labels.

Abstract: An optical disk comprises a disk substrate having a hub and an annular optical metallicized data region extending radially outward from the hub. The optical disk further comprises a radio frequency identification (RFID) transponder affixed to the disk substrate, e.g., within the non-data containing hub region. The optical disk further comprises at least one linear antenna element coupled to the transponder, e.g., via pole lead(s), and extending within the data region. The antenna element(s) can be applied to the disk substrate as a patterned antenna layer over a metallicized data region, and can be electrically isolated from the data region. A method and system of identifying an optical disk is provided. A radio frequency (RF) signal can be transmitted to the optical disk at a range of at least five feet, and preferably at a range of at least ten feet. An RF signal with an identification code (e.g., a unique number) can be received from the optical disk in response to the transmitted RF signal.

Abstract: A method and apparatus for activating an optical media device with a conditional access mechanism is presented. The optical media device is configured with a conditional access system such as an optical shutter assembly and the apparatus is configured to receive such an optical media device and establish communication with the optical media device. The apparatus may include one or more electrodes that are positioned such that they come into physical or near physical contact with a corresponding electrode on the optical media device and thereby establish electrical communication. The apparatus may also be configured to send and receive acoustical signals to establish an acoustical communication path with the optical media device. A data communication path may also be established between the optical media device and the apparatus. Upon establishing communication with the optical media device, the apparatus may send an activation signal to the optical media device to activate the conditional access system.

Abstract: Described herein are a molecular memory obtained using DNA strand molecular switches and carbon nanotubes, and a manufacturing method thereof. In particular, the nonvolatile memory is manufactured according to an architecture that envisages the use of carbon nanotubes as electrical connectors and DNA strands as physical means on which to write the information. In other words, the nonvolatile memory is made by means of a set of molecular DNA strand switches, the addressing of which is controlled by molecular wires made up of carbon nanotubes.

Abstract: A system and method for wireless activation of a target. A communication device transmits an ID associated with the target to a network operations center. The network operations center provides an activation signal to the communication device. The communication device wirelessly transmits an acoustic activation signal to a nearby activation device. The activation device is positioned proximate the target and causes a change in at least one physical property of the target. The target may be an optical media containing an electrochromic material with optical properties that change on application of an electric signal.

Abstract: A secure optical data disc comprising an electronic article surveillance tag embedded within a layered disc structure comprising first and second substrates is disclosed. The tag is placed within a non-readable zone (i.e., one that does not have data tracks) of the secure disc. To improve signal quality of the tag, the reflective metal layer thickness is minimized and discontinuities are introduced on the reflective metal layer. A first discontinuity separates a data track region of the disc from a mirror/ID band region. A second, radial discontinuity opens the mirror/ID band ring.

Abstract: A secure optical data disc comprising an electronic article surveillance tag embedded within a layered disc structure comprising first and second substrates is disclosed. The tag is placed within a non-readable zone (i.e., one that does not have data tracks) of the secure disc. Layer-wise, the tag is either sandwiched between the two substrates or alternatively embedded within one of the two substrates. In the case where the tag is sandwiched between first and second substrates, a bonding layer occupies a space radially outward from the tag.. The bonding layer holds the first and second substrates together thereby forming the secure disc.

Abstract: An index print of photographic images is created on a CD containing digital data representing those images. Photographic images are digitized to produce digital image data which is stored on the CD. This digital image data is also used to create an index print containing thumbnail images of all of the photographs stored on the CD. The index print is then affixed to the top surface of the CD either by being printed on a label that is adhered to the disk surface, or by being printed directly on the surface of the disk.

Abstract: A system is designed for highly customizing and personalizing a greeting card through the association with a digital recording media. The CD can include a writable track for recording the user's voice input and a writable track for recording other audio and/or video input. The CD can, additionally be provided with a track prerecorded with words and music based around specific occasions, such as Mother's Day, Christmas, etc. and can be provided with a track on which is prerecorded instrumental music for use karaoke style. As a further option, the CD can be provided with a writable track for recording the user's voice merged with the music on the instrumental track.

Abstract: The invention provides an electrophotographic laminated film and a method for producing the electrophotographic laminated film. The electrophotographic laminated film comprises a substrate and at least one of a coating layer and a function control means provided on a surface of the substrate. The uppermost layer of the coating layer has a surface resistance in a range of 1.0×108 to 1.0×1013 ?/?. The surface of the substrate preferably comprises at least one of a polycarbonate resin and a polyallylate resin. At least one of the coating layer and the function control means is preferably formed by providing a coating liquid. Further, a solvent contained in the coating liquid is preferably permits at least one of the coating layer and function control means to be formed while dissolving the surface of the substrate.

Abstract: An information recording medium including at least one electrophotographic laminate film in which a surface resistance of at least one surface is in a range of 108 to 1013 ?/?, and on which a toner image corresponding to information is formed; and an opaque core base material laminated on the surface of the electrophotographic laminate film, on which surface the toner image is formed.

Abstract: In a digital audio signal player having a simulated analogue record, a high frequency alternator is provided, which is connected to the microprocessor, and constantly sends out a high-frequency signal; the alternator has an output terminal electrically connected to a diode connected to the microprocessor; a control element is also connected to the diode. Music is played in a normal way when the microprocessor receives high-frequency signal in a non-reduced form. The control element will send an interfering signal to the diode to reduce high frequency signal passing through the diode when touched by hands, thus making the microprocessor receive high frequency signal in reduced form; music is played with speed and direction changing according to the movement of the control element when the microprocessor receives the reduced high frequency signal. Music is played normally as soon as hands are removed from the control element.

Abstract: A secure optical data disc comprising an electronic article surveillance tag embedded within a layered disc structure comprising first and second substrates is disclosed. The tag is placed within a non-readable zone (i.e., one that does not have data tracks) of the secure disc. Layer-wise, the tag is either sandwiched between the two substrates or alternatively embedded within one of the two substrates. In the case where the tag is sandwiched between first and second substrates, a bonding layer occupies a space radially outward from the tag. The bonding layer holds the first and second substrates together thereby forming the secure disc.

Abstract: A recording type optical disk on which data is recordable includes a data recording and reproducing area for recording data therein and reproducing data therefrom, and a read-only disk identification information area for recording disk identification information for identifying the optical disk therein. In the optical disk, the disk identification information is formed by removing a reflection film that is formed on the optical disk in a strip shape. The disk identification information includes an inherent disk identifier for each optical disk, and the data recording and reproducing area includes an area for recording encrypted data therein. The encrypted data is encrypted by using information including the disk identification information for identifying the optical disk as a key.

Abstract: An optical disk of the type rotated by a spindle positioned in a centrally-located hole, and including a disk body including an annular data area, and a centrally-located, integrally-formed annular web positioned radially inward from the annular data area and covering a hole formed in the disk body. The annular web is formed sufficiently thin to be deflected upwardly out of the plane of the disk body by the spindle during placement on the spindle and during rotation. The web may be broken away from the disk, or made sufficiently thin and resilient that it will deform upwardly when placed on the spindle and resume its former position when removed.

Abstract: A near-field optical recording medium comprises a recording layer capable of writing, reading and erasing information using an evanescent light, the evanescent light having a beam spot size smaller than the wavelength of a source light, wherein the recording layer is a stable amorphous layer mainly comprising a photochromic compound having a glass transition point of 55° C. or higher and a molecular weight of 3000 or less.

Abstract: An optical disk with an embedded security device, or wafer, is presented. The security device includes security features that enable the identification of genuine optical disks versus counterfeit optical disks. Methods for creating optical disks embedded with security devices are also presented. A security device is placed on the center pin of an open mold before the optical disk is formed. Alternatively, an optical disk having a cavity formed on a surface to receive a security device is created. A special mold with a raised platform creates the cavity on the optical disk. As a further alternative, two optical platters, each having a complementary cavity to accommodate a security device are created using a special mold having a raised platform. The security device is inserted into the complementary cavities and the optical platters and security device are bonded together.

Abstract: According to one aspect a method for manufacturing a holographic storage medium includes providing one or more data masks with data to be recorded, illuminating the one or more data masks onto the medium with a plane wave object beam from a laser light source operating at a record wavelength, propagating a reference beam at an incident angle to the medium to record the one or more data masks on the medium, and altering the incident angle of the reference beam for each of the one or more data masks, wherein each of the one or more data masks recorded on said medium can be read bit by bit using a laser light source operating in a readout range of wavelengths different from the record wavelength.

Abstract: An annular protective rim attachment designed to grip the outer peripheral edge of compact discs (CD's) and digital video discs (DVD's), consisting of a flexible, flat top rim (10), the inner periphery of which is molded to form an upper lip (12), lower lip (14), and between these lips, a gripping mouth (16) to securely hold the CD or DVD (28) inside the aperture of said ring. The underside of said ring is shaped in such a way as to create an airfoil (20) adequate to enable the airfoil ring with attached CD or DVD (28) to safely fly and exhibit controllability when tossed into the air. The airfoil ring is made of a soft, flexible non-malleable plastic material which will create a cushioning effect so as not to produce contact impact and resultant injury or damage when tossed into the air.

Abstract: A regeneration device of an exhaust gas purification filter that reduces the regeneration time of the filter. The regeneration device includes a plurality of first temperature detectors arranged in casings to detect the temperature in each casing and a second temperature detector for detecting the temperature of the exhaust gas. A processor is connected to the first temperature detectors and the second temperature detector. The processor compares the temperature of the exhaust gas and the temperature of at least one of the casings, opens the associated switch valve based on the comparison result, and preheats at least one of the filters with the exhaust gas. The heat of the exhaust gas suddenly increases the temperature of the filter from the initial temperature and reduces the filter regeneration time.

Abstract: A CD Card for packaging card like information and digital information in the basic dimensions (length and width) of a business, credit or collectors card. The CD Card is made up of one, two, or three major components. The first component is a small compact disc with dimensions small enough to be contained within the typical dimensions (length and width) of a business card, credit card, or collectors card. The second component is a container shaped like a business, credit, or collectors card in length and width, but with a depth large enough to hold the small compact disc and adaptor (if required) discussed subsequently. The third component is an adaptor designed to position the small compact disc of the first and third embodiments of the present invention correctly in standard CD drives. A second embodiment of the small compact disc may not require an adaptor or case.

Abstract: Disclosed is a method for producing an information-recording medium comprising, on a substrate, a dye recording layer capable of recording information, the method comprising the step of drying the substrate formed with the dye recording layer by allowing clean air to flow while rotating the substrate at a high speed; wherein an intake for introducing the clean air is narrowed by arranging a lid having a circular opening at a central portion, at an opening disposed at an upper portion of an apparatus for rotating the substrate at the high speed.

Abstract: A method of one embodiment of the invention is disclosed that generates a non-Cartesian coordinate system for an optical disc. One or more uniform distances, as well as a plurality of positions on the optical disc, are selected. Each position is separated from adjacent positions by one of the uniform distances, and has a location on the optical disc specifiable to a same degree of precision by at least one integral coordinate.

Abstract: A method for labeling an optically writable label side of an optical disc of one embodiment of the invention is disclosed which includes at least one of the following. First, the method may multiply pass over a track of the optically writable label side of the optical disc with an optical marking mechanism, such that the optical marking mechanism writes to the track during each pass. Second, the method may advance the optical marking mechanism from the track to a next track of the optically writable label side of the optical disc, such that a starting position on the track is radially non-collinear with a starting position on the next track.

Abstract: An annular protective ring attachment designed to grip the outer peripheral edge of all compact discs (CDs) and digital video discs (DVDs) which, when used in combination with said CD or DVD, creates an airfoil. The airfoil ring consists of an inner periphery, which is molded to form a top lip (3) and bottom lip (4), and between these lips, a gripping mouth (6), which securely holds the CD or DVD (7,76) inside the aperture of the airfoil ring. The body of the airfoil ring is curved in such a way as to create an airfoil adequate to enable the airfoil ring with inserted CD or DVD to be safely tossed into the air and to exhibit controllability in flight. The airfoil ring is constructed of a soft, flexible plastic material, and uses a hinge groove (5) on the top side of the airfoil skirt (1) and a hinge groove reaction area (9) on the underside of the airfoil skirt (1) to dissipate the contact force upon impact and create a cushioning effect so as to avoid resultant injury or damage when tossed into the air.

Abstract: A system for recording data to a disc shaped record medium. The data is recorded according to a universal disc format employing a hierarchical file system, and data within the hierarchical structure is referenced using pointer information. The pointer information includes a file identifier descriptor and a file entry and is recorded such that the pointer information and its corresponding substantive data are stored at successive addresses.

Abstract: A promotional article and a method for assembling the promotional article is disclosed. The promotional article includes a product, a flexible data carrier placed over the product, and a cover which secures the flexible data carrier to the product. The promotional article may further include advertising indicia on the flexible data carrier. The method includes the steps of: providing a product, placing a flexible data carrier on the product, and covering the flexible data carrier and product with a cover.

Abstract: An information disk has a disk structure with a metalized data storage area. A radio frequency identification processor that is activatable by light, such as laser light, is coupled to the disk structure to prevent copying of copyrighted or otherwise secured data, and to prevent unauthorized use of the information disk. The processor may be positioned at a variety of locations on the information disk, including in the inner non-conductive area, and the outer non-conductive ring, as well as within the metalized data storage area. A process for enabling an information disk with an RFID processor includes providing a disk structure having a metalized data storage area, and positioning a short wavelength electromagnetic light activated radio frequency identification processor on the disk structure.

Abstract: An information disk includes an annular disk structure having a surface with a metalized data storage area coupled to the surface. An antenna is affixed to the disk surface and positioned radially inwardly from the metalized data storage area. A radio frequency identification processor is coupled to the disk surface and the antenna. A non-conductive gap is positioned between the metalized data storage area and the antenna and the processor is positioned in the gap. A protective coating is positioned on the disk structure The processor may also be positioned radially inwardly from the antenna. A process for enabling an information disk with a radio frequency identification processor is also described. The process includes providing a disk with an outer metalized data storage portion and an inner antenna portion, with the portions separated by a gap for accommodating a processor.

Abstract: A harmonic responsive electronic article surveillance marker is associated with a central, non-recorded region and/or a peripheral non-recorded region of an optically recorded or recordable media. The marker comprising at least one elongated strip, optionally having an arcuate configuration, and composed of soft magnetic material adapted to generate a harmonic signal voltage in the presence of an applied magnetic field which provides the marker with signal identity. Advantageously, the marker is inexpensive to construct. It is readily attached to or embedded in the non-recorded region and/or the peripheral non-recorded region, and generates a high amplitude, harmonic signal voltage having significantly increased detection sensitivity. With these attributes, the marker is especially suited for electronic surveillance of recorded media such as compact disks, digital video disks, laser disks and the like.

Abstract: A recording disk having a recording medium and a memory assembly which is disposed in an annular or spiral form at a certain position on the disk. The memory assembly which a memory which stores information, a signal processor which writes or reads out information to/from the memory, a transmitter-receiver for transacting information with an exterior of the disk, a controller which controls the memory, signal processor and transmitter-receiver, a receiver which receives power in the form of a signal supplied from an exterior of the disk for the operation of the memory, signal processor, transmitter-receiver and controller, and a rectifier converts the signal received by the receiver into power. The memory, signal processor, controller, rectifier, and transmitter-receiver and/or receiver are at least partially formed of a semiconductor integrated circuit and at least portions of the memory, signal processor and controller are covered with light-blocking resin.

Abstract: The present invention provides a rewritable compact disk (CD-RW) having determining function for record data comprising a transparent substrate, a recording layer, a reflection layer, a protection layer, and a labeling layer, the improvement includes an uncovered scale portion located in said labeling layer for determining record data of said CD-RW from a side of said labeling layer.

Abstract: The present invention relates to improved methods and systems for manufacturing optical storage media from which information can be read out and/or into which information can be recorded by means of a beam of electromagnetic radiation. Furthermore, the present invention relates to an improved optical storage medium which can be obtained with the method and system of the present invention. The optical storage medium comprises various layers (1, 5, 7), wherein at least two of them are bonded by means of a pressure sensitive adhesive layer (4). At least the adhesive layer is cut by means of a laser beam so that the disadvantages of mechanical cutting tools are overcome.

Abstract: A first surface optical disk is disclosed that has machine readable code information, such as bar code information, disposed thereon to permit a disk drive or other device to obtain certain basic information regarding the disk in an efficient and reliable manner. The machine readable code may include error detection and error correction code to correct errors, such as those caused by surface dust, that may arise during reading the machine readable code. The machine readable code may be disposed within a portion of a ring on the optical disk. Human readable alphanumeric characters, including graphics, identifying the side of the optical disk and other basic information may also be disposed within the ring.

Abstract: A compact disc (10) for a computer incorporates a security device for preventing non-authorised reading of data carried by the disc. The security device includes an LCD laser blocker (16) which is activated or deactivated by means of a microchip (13) powered by a cell (14) and/or solar panel (15). Authorised reading of the data is possible by a fingerprint scanner (12) linked to the microchip and causing it to deactivate the blocker (16), when the scanner recognises a user's fingerprint which the microchip matches to a programmed authorised fingerprint. Also disclosed is a data carrying compact disc (20) which incorporates security means to allow a first reading of the data of the disc, but to prevent such reading thereafter. An area (21) of the disc, such as a FAT file, can be arranged to be destroyed or blocked, to prevent subsequent reading thereof by the disc reading means.

Abstract: An optical disk includes a disk substrate made of synthetic resins and an elastic/non-elastic film for label printing. The disk substrate has a chucking central aperture, and the peripheral portion of the chucking central portion constitutes a clamping area. The film is fixed on an upper surface of the disk substrate so as to cover the chucking central aperture. In case of the elastic film, at least a portion of the film corresponding to the chucking central aperture expands/contracts in accordance with the movement of a disk chuck into/out of the chucking central aperture. On the other hand, in case of the non-elastic film, cuts are made in a portion corresponding to the chucking central aperture, whereby the cut portion of the film opens/closes in accordance with the movement of a disk chuck into/out of the chucking central aperture.

Abstract: A digital business card has a rectangular substrate and a magnetic stripe. The substrate has a printing surface disposed on a surface of the substrate for printing visual data, and a photo-recording region disposed on the rear of the substrate for storing digital data. The magnetic stripe is disposed on the surface of the substrate adjacent to a short side of the substrate for recording magnetic recording data and storing a specific encoded password. The digital business card effectively controls reading data in the digital business card through the combination of the magnetic stripe and the photo-recording region so as to prevent the data from being stolen. Besides, the digital business card has the same size as a conventional printed business card, so that the digital business card is carried handily and has high capacity of storing data.

Abstract: The present invention is an interactive transaction card having an optical disk which is readable by a CD ROM drive. A coded strip, such as a magnetic strip, is disposed on one side of the optical disk. The magnetic strip has an identification code, such as an account number, which identifies a user's credit or debit account. The optical disk is further configured so that by inserting it into a magnetic card reader, the reader is able to derive the identification information for a transaction. The same identification code may also be stored on the optical disk to allow the CD ROM drive to read and utilize the identification information. The optical disk may contain multimedia modules including various audio, moving or still pictures, graphics, and video files. The optical disk may also contain additional modules programmed to connect to the Internet to facilitate electronic commerce or to provide additional information on a web site.

Abstract: An object of the present invention is to provide a marking forming apparatus, a method of forming a laser marking on an optical disk, a reproduction apparatus, an optical disk, and a method of manufacturing an optical disk, capable of providing a greatly improved copy prevention capability as compared to prior known construction. To achieve this object, in the optical disk of the invention, for example, a marking is formed by a laser on a reflective film of a disk holding data written thereon and at least position information of the marking or information concerning the position information is written on the disk in an encrypted form or with a digital signature appended thereto.