Abstract: Quality judgment on a laser beam intensity distribution is performed by taking an observation condition of the laser beam into consideration. A machine learning device includes: a state observing means that acquires data indicating an intensity distribution of a laser beam and data indicating a condition for observing the laser beam, performed to generate the data indicating the intensity distribution as input data; a label acquisition means that acquires an evaluation value related to judgment of the quality of the laser beam as a label; and a learning means that performs supervised learning using a pair of the input data acquired by the state observing means and the label acquired by the label acquisition means as training data to construct a learning model for judging the quality of the laser beam.

Abstract: Quality judgment on a laser beam intensity distribution is performed by taking an observation condition of the laser beam into consideration. A machine learning device includes: a state observing means that acquires data indicating an intensity distribution of a laser beam and data indicating a condition for observing the laser beam, performed to generate the data indicating the intensity distribution as input data; a label acquisition means that acquires an evaluation value related to judgment of the quality of the laser beam as a label; and a learning means that performs supervised learning using a pair of the input data acquired by the state observing means and the label acquired by the label acquisition means as training data to construct a learning model for judging the quality of the laser beam.

Abstract: To obtain a signal quality evaluation value capable of having a high correlation to an error rate and high accuracy for a reproduction signal of high density recording. For the object, an estimated value of a path selection error rate is obtained on the basis of a distribution of a path metric difference between a maximum likelihood path at each time, which is a detection path in maximum likelihood decoding in a PRML decoding system and a second path having a second highest likelihood. Further, an average error bit number in erroneous detection is obtained from a bit difference number between the maximum likelihood path and the second path at the time of path selection of each time in the maximum likelihood decoding. In addition, an estimated bit error rate is obtained from results and an evaluation value according to the estimated bit error rate is generated.

Abstract: Described are embodiments of an invention for a sample assembly with trenches for detection of analytes with electromagnetic read heads. The sample assembly includes an outer layer with at least one sample trench. The sample trench includes a first set of antibodies that are bonded on a first surface of a base layer. Target antigens are bonded with the first set of antibodies, and a second set of antibodies are bonded to the target antigens. Further, the sample trench includes nanoparticles that are bonded to the second set of antibodies. A head module includes a write head for magnetizing nanoparticles and a read sensor for detecting the magnetized nanoparticles, and thus, the target antigens. The sample trench constrains the biological sample, and thus the target antigen, during the preparation and subsequent analysis of the biological sample. Accordingly, the target antigen is aligned with read elements of a head module such that the target antigen is reliably and accurately detected.

Abstract: A testing device for testing performance parameters of a disc player which includes a display, and a storage. The storage at least one sector table associated with a disc in the disc player, each sector table recording sector information corresponding to a plurality of physical sectors of the disc, a testing command associated with each physical sector, and a reference value range of each of performance parameters of the disc player. The testing command corresponding to the physical sector of the disk is obtained to be executed by the disc player to obtain a value of each performance parameter of the disc player. The testing device determines whether the disc player is qualified or not according to the obtained value.

Abstract: A videoconference may be initiated between a plurality of endpoints. At least one of the endpoints may be coupled to a recording server, which may be configured to record the videoconference. A configuration may be selected (e.g., automatically or manually) for performing the recording. The endpoint (e.g., acting as an MCU) may transmit information to endpoints and may transmit recording information to the recording server. The recording information may be different from the videoconference information. For example, it may be in a “streaming friendly” format, at a different bit rate, encoded differently, have different inputs, etc. The manner in which the videoconference is stored and/or recorded may be based on the selected configuration. Clients may be configured to receive and display the videoconference from the recording server and may be configured to change the provided layout to different layouts, e.g., based on user input.

Abstract: A disc player plays a test disc to perform a burn-in test. The disc player includes a driving unit, a timing unit, storage, an input unit and an output unit. The driving unit plays the test disc and generates a first timing signal when begin to play the test disc. The timing unit counts the duration of the burn-in test from a default value in response to the start signal. The storage stores the duration counted by the timing unit in real time. The input unit generates an output signal in response to a first user operation. The output unit outputs the stored duration in response to the output signal.

Abstract: This invention provides an information processing method and apparatus, which can set all extent sizes of data divisionally recorded on a disk to be equal to or larger than the minimum recording unit, and can guarantee continuous reproduction of the divisionally recorded data. Of data divisionally recorded on a recording medium (5), data which corresponds to an end portion of that data and cannot be recorded as a recording area equal to or larger than a minimum recording unit specified in the recording medium (5) due to the presence of a recording area (6) of another data, that has already been recorded on the recording medium (5), is re-recorded on a recording area equal to or larger than the minimum recording unit. At this time, new data is generated by combining data less than the minimum recording unit, and data recorded in another recording area, and the new data is re-recorded on a new recording area.

Abstract: To ensure a favorable recording characteristic for a write-once recording medium for a bluish-purple laser, an optical information recording apparatus includes ways to write power to form recording marks, a space forming power to form spaces, a pulse width of a cooling pulse and ways to record information onto the optical information recording medium according to the setting of the write power, the setting of the space forming power and the setting of the pulse width of the cooling pulse. At this time, the pulse width of the cooling pulse and a ratio whose numerator is the write power and whose denominator is the space forming power have a preferable region of the recording characteristic, and information is recorded onto the optical recording medium by using values in this range.

Abstract: A data recording and reproducing apparatus relative to a data library device includes a plurality of setup units for recording and reproducing data in a record and reproduction condition appropriate to a recording medium, and a storage unit for storing identification information and medium information of the recording medium, in this way, a setup processing is performed to reproduce the identification information from the recording medium when loading the recording medium, the medium information corresponding to the identification information is read out from the storage unit to perform the setup processing by a second setup unit when the medium information corresponding to the identification information is present in the storage unit, and the setup processing is performed by a third setup unit to reproduce the medium information from the recording medium and store in the storage unit together with the identification information, shortening a time period of the setup processing.

Abstract: In an optical disk library device using a plurality of optical disk devices, before optical disk devices execute recording or reproduction of information to or from optical disks, self-monitoring information is acquired from an optical disk monitor, use preferential orders of the optical disk devices are evaluated on the basis of use frequency information or deterioration information included in the self-monitoring information and an optical disk device to be used for recording or reproduction of information is selected on the basis of the use preferential orders.

Abstract: An optical disc type is determined by detecting focus error signals and an amount of returned light, while (i) emitting light having a wavelength maximizing a focal length and (ii) moving an objective lens in a direction of an optical axis. If an S shape and AS immediately after a surface are greater than those at the surface, the optical disc is determined to have a largest capacity. It is also determined whether there is a reflective layer at a depth equal or less than 0.1 mm, if not, then it is determined whether there is a reflective layer at a depth of 0.6 mm. If there is a reflective layer at the depth of 0.6 mm, then the type of the reflective layer is determined based on TE/RF signals, using blue light. If the blue light is not adaptable, red light is emitted to replay at a depth of 0.6 mm.

Abstract: A method and system for obtaining focus optimization in an optical disc system is disclosed. The focus offset of a recording unit is set to a first of a plurality of predetermined values. A HF quality value is measured and stored for the selected focus offset value of the recording unit. The focus offset is then set to a best-known focus offset value. Tracks on the optical media being read are then jumped. The above steps are then repeated for each of the plurality of predetermined focus offset values. The optimal focus setting is then determined from the stored HF quality measurements.

Abstract: A product mark including a public key certificate issued with respect to an information-recording-medium manufacturing entity or information-recording-medium manufacturing equipment, and an encrypted volume ID calculated by computation based on a product-mark-associated value such as a hash value generated on the basis of the product mark, and a volume ID as an identifier set with respect to a given set of discs to be manufactured, are generated. The product mark and the encrypted volume ID are set as information for generating a key used for decryption of encrypted content, and recorded onto a disc by a reflective-film-removal recording method. Due to this configuration, the product mark and the encrypted volume ID as key generating information cannot be read from a pirated disc produced by physically copying a pit pattern on the basis of a legitimate commercial disc, thereby making it possible to prevent unauthorized reproduction or use of content.

Abstract: Described is an optical information medium measurement method of measuring a degree of modulation in an optical information medium of a multilayered structure having a plurality of information layers. The method includes measuring the modulation degree of each layer of the optical information medium, by use of a measurement optical system, obtaining a thickness between layers of the optical information medium, obtaining a reflectance of each layer of the optical information medium, and converting the measured modulation degree of each layer into a modulation degree at a reference optical system differing from the measurement optical system, based on a value indicative of the obtained thickness between layers and a value indicative of the obtained reflectance of each layer.

Abstract: A method for determining an eccentricity of an optical disc is provided. The method includes predetermining a plurality of optical disc with known eccentric distances, respectively measuring a ratio of maximum and minimum amplitudes of a tracking error signal of the optical discs, establishing an eccentric distance ratio table or curve, measuring a ratio of maximum and minimum amplitudes of the tracking error signal for an optical disc under test, and comparing the measured ratio with the table or curve to promptly determine the eccentricity distance of the optical disc under test.

Abstract: A calibration circuit and a calibration method thereof for data recovery are provided. The calibration circuit includes an amplitude detector, a period detector, and a compensation circuit. The amplitude detector samples amplitudes of a data signal according to a zero-crossing signal and outputs an amplitude signal accordingly. The period detector counts a clock signal according to the zero-crossing signal and outputs a period signal accordingly. The compensation circuit receives the amplitude signal, the period signal, and the data signal. The compensation circuit adjusts a phase of the data signal by calculating differences between a reference signal and the amplitude signal and between the reference signal and the period signal and outputs a calibrated data signal accordingly. Accordingly, a better recognition performance on the data signal is achieved by calibrating the data signal in real-time.

Abstract: A signal pattern detecting apparatus, which is capable of detecting a physical mark in a read back signal being read from an optical disc, includes a matching signal generator, a signal comparing device, and a decision circuit. The matching signal generator is utilized for generating a matching signal, capable of being utilized to identify the physical mark, according to a reference clock and a wobble clock. The signal comparing device is electrically connected to the matching signal generator, and utilized for comparing the matching signal with a wobble data signal to generate a comparison signal. The decision circuit is electrically connected to the signal comparing device, and utilized for generating an indication signal according to the comparison signal and a threshold value. Both the wobble data signal and the wobble clock are derived from the read back signal.

Abstract: An optical information medium measurement method measures a degree of modulation in an optical information medium of a multilayered structure having a plurality of information layers. The method includes measuring the modulation degree of each layer of the optical information medium, obtaining a thickness between layers of the optical information medium, obtaining a reflectance of each layer of the optical information medium, and converting the modulation degree of each layer. The modulation degree is measured based on a value indicative of the thickness between layers, and a value indicative of the reflectance of each layer.

Abstract: An optical information medium measurement method, for measuring a degree of modulation in an optical information medium of a multilayered structure having a plurality of information layers, includes a first step of measuring a modulation degree of each layer of the optical information medium, and a second step of obtaining a thickness between layers of the optical information medium. Further, the method includes a third step of obtaining a reflectance of each layer of the optical information medium, and a fourth step of converting the modulation degree of each layer, as measured in the first step, into a modulation degree at a reference optical system differing from the measurement optical system, based on a value indicative of the thickness between layers, the thickness being obtained in the second step, and a value indicative of the reflectance of each layer, as obtained in the third step.

Abstract: The recording accuracy of information on an optical disc is increased. An information optical system (150) of an optical disc apparatus (110) enables a semiconductor laser (3) to sequentially output specific peak light (LEP) and specific slope light (LES) as an information light beam (LM) and enables the correction lens (162) to change the divergence angle of the specific peak light (LEP) so that an absorption change area (RA) by the specific peak light (LEP) can be positioned at a far position in the recording layer (101). Thus, it is possible to form an energy concentration area (RE) by the specific slope light (LES) in the vicinity of a target position (QG), and the recording accuracy of information on the optical disc (100) can be increased.

Abstract: A method for detecting the obliquity of an optical disc drive is provided. The method includes the steps of calibrating balance gains of TE signals and CE signals with predetermined obliquities of the optical disc drive, curve-fitting and storing a relating function between the predetermined obliquities and the balance gains, calibrating the balance gains of signals for an installed optical disc drive, and acquiring an calibrated balance gain to find the obliquity of the optical disc drive from the relating function.

Abstract: A method of storing a data storage device includes but is not limited to emplacing a data storage device in a container, the container having surfaces; and writing storable data to the data storage device by transmitting energy through a surface of the container. In addition to the foregoing, other method aspects are described in the claims, drawings, and text forming a part of the present application. Other methods and apparatuses are also disclosed.

Abstract: According to one embodiment, an information storage medium includes an organic dye material which records information with a light beam having a wavelength equal to or smaller than 620 nm.

Abstract: Various embodiments herein include one or more of systems, methods, software, and/or data structures to test and evaluate unformatted optical media such as optical tape and optical discs. Advantageously, testing and evaluation can be performed earlier in the manufacturing process of the optical media to locate defects and/or other problems or issues with the optical media that can be addressed before additional manufacturing steps are performed and possible wasted. The systems and methods include at least two optical pickup units (OPUs), a first of which may be dedicated to writing digital data and the second of which may be dedicated to scanning, locating, tracking and/or reading the written data (when the optical media is moving in a first direction) in one of a plurality of manners. Information (e.g.

Abstract: An apparatus and a method for testing spoke sensor are disclosed. A drive unit is started to rotate a test disc to a predetermined rotation speed. A module test unit is electrically connected to a spoke sensor under test of a spindle motor module. The module test unit is started to drive the spoke sensor to detect the spoke signals of the test disc and record the number of detected spoke signals. Within a test time, a comparison unit is used for comparing the number of spoke signals with a threshold, and only when the detected number is larger than a threshold will the spoke sensor be assembled to the product. Thus, the product quality is assured.

Abstract: According to one embodiment, a reproduction apparatus includes an execution unit configured to execute an advanced application, a detection unit configured to detect a series of keys which are operated by a user while the advanced application is executed, a recording unit configured to record key macro information formed of the detected series of keys and operation timings of the series of keys, and a key event generating unit configured to read the key macro information recorded by the recording unit and to generate a series of key events corresponding to the series of keys at the operation timings.

Abstract: An optical disk device which flexibly and efficiently executes verification of recorded data is provided. A drive controller sets an area to be verified and a mode of verification according to a command which is supplied from a host device. For the area to be verified, the user selects one or a plurality of lead-in, inner, middle, and outer areas. For the verification mode, the user selects one of an immediate execution mode and an in-close-command execution mode. In a duplicator or the like in which same data is recorded on a plurality of optical disks, the user can designate an important data portion and selectively execute verification.

Abstract: A signal evaluation method according to the present invention is a method for evaluating a read signal, retrieved from an information recording medium, based on a binarized signal generated from the read signal by a PRML method.

Abstract: Disclosed is a system for generating an output signal indicating a specific area on an optical disc. The system includes an optical pick-up head signal generator, a detecting apparatus, and an output signal generating apparatus. The optical pick-up head signal generator is used for generating an optical pick-up head signal. The detecting apparatus is used for detecting pre-recorded address information on the optical disc to generate a detection signal. Also, a output signal generating apparatus, which is coupled to the optical pick-up head signal generator and the detecting apparatus, is used for receiving the optical pick-up head signal and the detection signal to generate the output signal according to at least one of the optical pick-up head signal and the detection signal, the output signal generating apparatus not generating the output signal according to the optical pick-up head signal after a predetermined time.

Abstract: The data processor of the present invention can play back video and audio synchronously from an optical disk, on which video and audio data are stored in different areas. Each area consists of one or more unit areas. The data processor includes: a playback control section for giving instructions on how to read the video and audio data and how to play back the video and audio based on the read data; a head for reading the data from one of the unit areas after another in accordance with the instructions; and audio and video buffers for retaining the audio and video data read. The playback control section instructs that the audio data be read from a predetermined one of the unit areas to the audio buffer memory, and then instructs that the video data, which is to be played back over first and second periods of time, be read from a number n (where n is an integer equal to or greater than two) of unit areas to the video buffer.

Abstract: A modulation control system for use with a high frequency modulator is described. This system comprises a latch for selectively receiving enable signals, wherein the latch transmits a latched signal in response to receiving at least two of the enable signals; a selection device coupled to the latch for receiving the latched signal, a voltage source, and a terminal for receiving at least one of the enable signals, wherein the selection device transmits a selected signal; and a logic device coupled to the selection device and a terminal for receiving a modulated enable signal, wherein the logic device transmits a synchronized signal for either enabling or disabling the high frequency modulator in response to receiving the selected signal associated with at least one of the enable signals.

Abstract: A calibration circuit and a calibration method thereof for data recovery are provided. The calibration circuit includes an amplitude detector, a period detector, and a compensation circuit. The amplitude detector samples amplitudes of a data signal according to a zero-crossing signal and outputs an amplitude signal accordingly. The period detector counts a clock signal according to the zero-crossing signal and outputs a period signal accordingly. The compensation circuit receives the amplitude signal, the period signal, and the data signal. The compensation circuit adjusts a phase of the data signal by calculating differences between a reference signal and the amplitude signal and between the reference signal and the period signal and outputs a calibrated data signal accordingly. Accordingly, a better recognition performance on the data signal is achieved by calibrating the data signal in real-time.

Abstract: An information processing device may include a first frame provided with a scanner for reading information recorded on a medium, a second frame which faces the first frame across a traveling path and is provided with a pressing member for pressing the medium toward a reading face of the scanner, a support plate which supports the pressing member and whose one end is axially supported with the second frame to be movable between a locked position where the pressing member is protruded in the traveling path and an open position where a reading face of the scanner is exposed, a locking part for locking the support plate to the second frame at the locked position, and a half lock preventing mechanism for preventing a half-lock state when the support plate is locked to the second frame.

Abstract: In a test disc, data (test data) is recorded in such a manner as to fill an entirety of a data region and, next to this test data, border-out data is recorded which contains information indicating that recording is prohibited. By determining whether the data can be played back appropriately from a position in the vicinity of an outer periphery of the disc where playback characteristics are apt to be unstable, whether the data can be played back appropriately from all of the regions is verified. Also, by determining whether it is possible to recognize that test disc is capable of recording, it is verified whether the border-out data can be smoothly acquired from the position in the vicinity of the outer periphery of the disc where playback characteristics are apt to be unstable.

Abstract: An assembly structure and method for an integrated laser/detector device with a mirror at an angle to redirect the laser beam to a medium. The mirror is not attached to the circuit board with the laser/detector as in the prior art, but rather is mounted separately in the housing immediately above the circuit board. This allows the circuit board to be moved laterally toward and away from the mirror during assembly to adjust the reflected beam along a first direction so that it contacts the photodetector. A hologram lens is mounted above the mirror, and can be rotated to adjust the reflected beam to hit the photodetector along a second, orthogonal direction. In one embodiment, two laser beams are generated, and two hologram lenses are used to separately adjust the two beams.

Abstract: An apparatus for modulating an incident beam includes a body that is non-transmissive and rotatable about an axis perpendicular to a surface of the body. The body has a first set of features including transmissive features with respect to the incident beam along a first radial path at a first radial distance from the axis and a second set of features including data storage features along a second radial path at a second radial distance from the axis. The apparatus also includes a reference sensor disposed over a first position along the second radial path. In the apparatus. the radial distances are different and the numbers of transmissive features and data storage features are relatively prime. When the body is rotating, the first set of features modulate the incident beam and the reference sensor generates a reference signal based on the data storage features traversing the first position.

Abstract: The disclosure provides an encoding device comprising a reflector, a rotating disk having at least one aperture; and an optical unit comprising a light emitter and a light detector. Said disk being positioned between said reflector and said optical unit whereby rotation of said disk causes the movement of said at least one aperture in an alternating manner into a path of said light, such that said path is periodically interrupted and reestablished.

Abstract: In an optical disk drive that is equipped with a binarization circuit by the PRML method and carries out record/reproduction at a speed higher than a standard speed, to realize reproduction compatibility between the drive and another optical disk drive by the ordinarily adopted direct slice method. It can be realized by applying verification judgment equivalent to reproduction at a standard speed in accordance with a reproduction speed. More specifically, it is realized by counting 2 T data number by the direct slice method, using a Viterbi decoder that validates a run length shorter than the minimum run length, and adopting other measures. A higher record/reproduction speed is realized while reproduction compatibility, which is an important original function of an interchangeable optical disk, is secured.

Abstract: An optical information medium measurement method of the present invention, for measuring a degree of modulation in an optical information medium of a multilayered structure having a plurality of information layers, includes a first step of measuring the modulation degree of each layer of the optical information medium, by use of a measurement optical system, a second step of obtaining a thickness between layers of the optical information medium, a third step of obtaining a reflectance of each layer of the optical information medium, and a fourth step of converting the modulation degree of each layer, the modulation degree being measured in the first step, into a modulation degree at a reference optical system differing from the measurement optical system, based on a value indicative of the thickness between layers, the thickness being obtained in the second step, and a value indicative of the reflectance of each layer, the reflectance being obtained in the third step.

Abstract: An optical disk drive, and a method of determining a write strategy thereof. In the method of determining a write strategy of an optical disk drive where a mark and a space are formed on an optical disk by a laser beam to display write information and information is written or reproduced, write quality is evaluated by combining at least two of power- and pulse-based parameters defining a writing multi pulse, and the at least two parameters are changed on a 2-dimensional matrix. The power- and pulse-based parameters indicating specific write quality are determined as strategy parameters, based on evaluated results of the write quality.

Abstract: An equalizer (22) performs a PR equalization of a reproduced signal waveform output from an A/D converter (21). A reference-waveform generation unit (42) generates a reference reproduced-waveform based on a recording data train estimated from the reproduced signal waveform by a recognition unit (30). An equalization-error calculation unit (43) calculates an equalization error between the reference reproduced-waveform and the reproduced signal waveform. A transient equalization-error detector (44) extracts equalization error information, as a transient equalization error, at the time instant at which the reference reproduced-waveform assumes a specific level, and at which the specific level-value and a level-value of the reference reproduced-waveform at one channel clock before or after the time instant satisfy therebetween a specific relative relationship. The extracted transient equalization error is used as an index showing the quality of the recorded mark.

Abstract: An optical disk device which quickly detects that a transparent disk is loaded is provided. When an optical disk is loaded, a drive controller of an optical disk device drives a spindle motor and checks existence of an optical disk based on a driving result. In addition, the drive controller drives an optical pickup to apply a focus control, to detect whether or not focusing is possible. When it is determined from the driving result that there is an optical disk and that focus is not possible, the drive controller judges that the optical disk (D) is a transparent disk.

Abstract: A file-based recordable disc playback apparatus includes a signal decrypting means 4 for decrypting a signal read from a recordable disc 1, a subcode analyzing means 5 for extracting subcode data from the decrypted signal, and for analyzing the subcode data, a decoding means 6 for decoding the decrypted signal, a file system analyzing means 10 for analyzing a file system on the basis of a decoded output, a TOC information processing means 11 for analyzing TOC data from a subcode analyzed output, a session information processing means 12 for processing session information on the basis of the analyzed data, a memory for storing various data from the above-mentioned analyzing means 10 and processing means 11 and 12, and an external interface 14 for changing a procedure for analyzing the file system according to an instruction from outside the apparatus.

Abstract: A combined digital versatile disc (DVD)/hard disk drive (HDD) system controls a HDD assembly and a DVD assembly comprises a DVD/HDD control module controls operation of the HDD assembly and the DVD assembly. Volatile memory communicates with the DVD/HDD control module and stores volatile data relating to the operation of the DVD assembly and the HDD assembly. Nonvolatile memory communicates with the DVD/HDD control module and stores nonvolatile data relating to the operation of the DVD assembly and the HDD assembly.

Abstract: A multi-layered recording medium, and a method and apparatus for recording data in the recording medium are disclosed. A multi-layered recording medium, each of which includes an inner area, a data area, and an outer area, includes: first layer having at least a test area assigned to the inner area; and second layer having at least a management area assigned to the inner area, wherein the test area in the first layer is not physically located at the same location as the management area assigned to the second layer adjacent to the first layer with respect to an incident beam.

Abstract: This invention provides an information processing method and apparatus, which can set all extent sizes of data divisionally recorded on a disk to be equal to or larger than the minimum recording unit, and can guarantee continuous reproduction of the divisionally recorded data. Of data divisionally recorded on a recording medium (5), data which corresponds to an end portion of that data and cannot be recorded as a recording area equal to or larger than a minimum recording unit specified in the recording medium (5) due to the presence of a recording area (6) of another data, that has already been recorded on the recording medium (5), is re-recorded on a recording area equal to or larger than the minimum recording unit. At this time, new data is generated by combining data less than the minimum recording unit, and data recorded in another recording area, and the new data is re-recorded on a new recording area.

Abstract: The invention comprises a method and device for application in a near-field optical system such that the robustness of the optical system and the system performance are enhanced. Use or threshold values, in combination with signals already present in the system, facilities protection by implementation of corrective actions to be taken in the event of the distance between refractive element and record carrier being determined to be outside threshold boundaries.

Abstract: A disk-shaped recording medium includes a transparent substrate, and an optical recording layer formed on the transparent substrate. A light source emits light. An optical head is operative for applying the light to the optical recording layer from the light source via the transparent substrate, for focusing the light on the optical recording layer, and for reproducing information from the optical recording layer. A position detecting device is operative for detecting at least one of a pit depth and a physical position of information which has a first given relation with a specified address and which is recorded on the recording medium, and for generating first positional information representing at least one of the pit depth and the physical position. A previously-recorded secret code is reproduced from the recording medium. The secret code represents second positional information. The secret code is decoded into the second positional information.

Abstract: A disk-shaped recording medium includes a transparent substrate, and an optical recording layer formed on the transparent substrate. A light source emits light. An optical head is operative for applying the light to the optical recording layer from the light source via the transparent substrate, for focusing the light on the optical recording layer, and for reproducing information from the optical recording layer. A position detecting device is operative for detecting at least one of a pit depth and a physical position of information which has a first given relation with a specified address and which is recorded on the recording medium, and for generating first positional information representing at least one of the pit depth and the physical position. A previously-recorded secret code is reproduced from the recording medium. The secret code represents second positional information. The secret code is decoded into the second positional information.