Abstract: An information recording and playback device includes a recording and playback unit, and a controller. The controller divides a recording area of an optical disk into a first recording area which is at an inner circumference side, and a second recording area which is at an outer circumference side. The controller controls the recording and playback unit such that the unit records or plays back data in the first recording area at a first speed, and records or plays back data in the second recording area at a second speed slower than the first speed. The predetermined radius is set to a boundary between an area in which a control residual exceeds a predetermined reference value when servo control related to focusing and tracking is performed on the recording area of the optical disk, and an area in which the control residual does not exceed the predetermined reference value.

Abstract: An optical disc medium includes a land and a groove at which information can be recorded. A predetermined number of address information units which record address information of the land or groove are provided in a circumferential direction of the optical disc medium. The address information unit of the land includes three or more address recording areas capable of recording address information. The address information is recorded on one area selected from among the three or more address recording areas. The address information unit of the land has address information which is recorded, in the same modulation, on the side of the inner adjacent groove and on the side of the outer adjacent groove. The one area to be selected from among the three or more address recording areas for recording the address information of the land is different among three address information units adjacently arranged in a radial direction.

Abstract: An optical disc medium includes a land and a groove at which information can be recorded. A predetermined number of address information units which record address information of the land or groove are provided in a circumferential direction of the optical disc medium. The address information unit of the land includes three or more address recording areas capable of recording address information. The address information is recorded on one area selected from among the three or more address recording areas. The address information unit of the land has address information which is recorded, in the same modulation, on the side of the inner adjacent groove and on the side of the outer adjacent groove. The one area to be selected from among the three or more address recording areas for recording the address information of the land is different among three address information units adjacently arranged in a radial direction.

Abstract: An optical disc medium includes a land and a groove at which information can be recorded. A predetermined number of address information units which record address information of the land or groove are provided in a circumferential direction of the optical disc medium. The address information unit of the land includes three or more address recording areas capable of recording address information. The address information is recorded on one area selected from among the three or more address recording areas. The address information unit of the land has address information which is recorded, in the same modulation, on the side of the inner adjacent groove and on the side of the outer adjacent groove. The one area to be selected from among the three or more address recording areas for recording the address information of the land is different among three address information units adjacently arranged in a radial direction.

Abstract: An information reproducing apparatus includes a photodetector (200A) divided by a dividing line parallel to a recording track scanning direction into a first light-receiving section (202, 203) that receives reflected light of a center section of a recording track and a second light-receiving section (201, 204) that receives reflected light of a portion adjacent, in a radial direction of an optical disc, with respect to the center section, a first adaptive equalization filter (107) that performs waveform equalization of an output signal from the first light-receiving section (202, 203), a second adaptive equalization filter (120) that performs waveform equalization of an output signal from the second light-receiving section (201, 204), and a data decoder (108) that decodes reproduction data based on an output waveform from the first adaptive equalization filter (107) and an output waveform from the second adaptive equalization filter (120).

Abstract: An information reproducing apparatus includes a photodetector (200A) divided by a dividing line parallel to a recording track scanning direction into a first light-receiving section (202, 203) that receives reflected light of a center section of a recording track and a second light-receiving section (201, 204) that receives reflected light of a portion adjacent, in a radial direction of an optical disc, with respect to the center section, a first adaptive equalization filter (107) that performs waveform equalization of an output signal from the first light-receiving section (202, 203), a second adaptive equalization filter (120) that performs waveform equalization of an output signal from the second light-receiving section (201, 204), and a data decoder (108) that decodes reproduction data based on an output waveform from the first adaptive equalization filter (107) and an output waveform from the second adaptive equalization filter (120).

Abstract: This optical read/write apparatus has first and second optical heads 2a, 2b and includes location control sections 4a, 4b which make the relative arrangement of the first and second optical heads 2a, 2b variable according to either the environmental temperature or from one medium to another. The first optical head 2a performs a write operation to record a mark on an optical storage medium 1, and the second optical head 2b reads the information that has been written by scanning the recorded mark. The apparatus further includes a nonvolatile memory which saves the relative arrangement of the first and second optical heads 2a and 2b either on an environmental temperature basis or on a medium by medium basis.

Abstract: An optical read/write apparatus according to an embodiment includes: an optical head unit (2a, 2b) which focuses a write light beam and a read light beam onto an optical storage medium (100) and which generates a signal based on the light beam that has been reflected from the optical storage medium; and a control section (6) which controls the optical head unit (2a, 2b) so that the optical head unit records a mark on the optical storage medium by irradiating the optical storage medium with the write light beam and reads the recorded mark on the optical storage medium with the read light beam. After having started to record the mark on the optical storage medium by irradiating the optical storage medium with the write light beam and before forming the recorded mark completely, the optical head unit (2a, 2b) reads the recorded mark on the optical storage medium with the read light beam.

Abstract: An optical read/write apparatus according to an embodiment includes: an optical head unit (2a, 2b) which focuses a write light beam and a read light beam onto an optical storage medium (100) and which generates a signal based on the light beam that has been reflected from the optical storage medium; and a control section (6) which controls the optical head unit (2a, 2b) so that the optical head unit records a mark on the optical storage medium by irradiating the optical storage medium with the write light beam and reads the recorded mark on the optical storage medium with the read light beam. After having started to record the mark on the optical storage medium by irradiating the optical storage medium with the write light beam and before forming the recorded mark completely, the optical head unit (2a, 2b) reads the recorded mark on the optical storage medium with the read light beam.

Abstract: This optical read/write apparatus has first and second optical heads 2a, 2b and includes location control sections 4a, 4b which make the relative arrangement of the first and second optical heads 2a, 2b variable according to either the environmental temperature or from one medium to another. The first optical head 2a performs a write operation to record a mark on an optical storage medium 1, and the second optical head 2b reads the information that has been written by scanning the recorded mark. The apparatus further includes a nonvolatile memory which saves the relative arrangement of the first and second optical heads 2a and 2b either on an environmental temperature basis or on a medium by medium basis.

Abstract: An optical head 12 reproduces information recorded on an optical disc 11, a BCA detector 21 and a medium discriminating circuit 22 acquire waveform distortion information for specifying a waveform distortion of a reproduction signal reproduced by the optical head 12, and a variable waveform equalizer 16 changes a parameter used in a distortion reduction processing for reducing the waveform distortion of the reproduction signal based on the waveform distortion information.

Abstract: A reproduction signal evaluation method evaluates the quality of a reproduction signal reproduced from an information recording medium based on a binary signal generated from the reproduction signal using a PRML signal processing system. A pattern extraction step extracts, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step computes a differential metric based on the binary signal; an extraction step extracts the differential metric which is not greater than a predetermined signal processing threshold; a step determines a mean value of the differential metrics which are not greater than the signal processing threshold and extracted in the extraction step; a standard deviation computing step determines a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step evaluates a quality of the reproduction signal using the standard deviation.

Abstract: The present invention provides a method for writing data on a multilayer optical disc with N information storage layers (where N is an integer and N?2). The kth deepest one (where k is an integer and 1?k?N) of the storage layers of the multilayer optical disc is called a kth information storage layer.

Abstract: According to the present invention, a first error pattern caused by a shift of a bit relating to a recording mark or a space of a shortest length and a second error pattern caused by an edge shift of the recording mark are used. For each of a plurality of error patterns, a pattern shift obtained by normalizing a difference between a square of a Euclidean distance between the error pattern and a reproduction signal and a square of a Euclidean distance between a correct pattern and the reproduction signal, using a square of a Euclidean distance between the correct pattern and the error pattern is detected. Length and phase errors are calculated by a sum of, or a difference between, a first pattern shift amount obtained by normalization performed using the first error pattern and a second pattern shift amount obtained by normalization performed using the second error pattern.

Abstract: An information recording medium according to the present invention includes an information recording layer on which information is recordable, and is evaluated using an evaluation index which is found based on a ratio of a center of an amplitude of a reproduction signal corresponding to a second shortest mark and a second shortest space, with respect to a center of an amplitude of a reproduction signal corresponding to a longest mark and a longest space.

Abstract: A most probable path is selected from a number n (where n?2) of paths of state transitions occurring from a first state Sk?j (where k?3 and j?2) at a time k?j into a second state Sk at a time k. The method includes the steps of detecting predetermined combinations of the first and second states Sk?j and Sk defining the n probable paths in a predetermined period j between the times k?j and k, and evaluating the reliability of a read signal, decoded in the period j, by |Pa?Pb|. Pa and Pb indicate the probabilities of state transition of first and second state transition paths in the period j. The first and second state transition paths are estimated to be the most probable and the second most probable, respectively, among the n probable paths defined by the combinations detected.

Abstract: A method for rating an information recording medium according to the present invention includes the steps of: receiving a digital read signal, which has been generated based on an analog read signal representing information that has been read from the information recording medium, and shaping the waveform of the digital read signal; subjecting the shaped digital read signal to maximum likelihood decoding, thereby generating a binarized signal showing a result of the maximum likelihood decoding; and calculating the quality of the digital read signal based on the shaped digital read signal and the binarized signal. If the quality of the read signal is calculated by a PRML method in which a number of zero-cross portions are included in a merging path of a minimum difference metric, the quality is calculated by using only a state transition pattern in which only one zero-cross portion is included in a merging path of a non-minimum difference metric.

Abstract: A reproduction signal evaluation unit includes a pattern detection section for extracting, from a binary signal, a specific state transition pattern which has a possibility of causing a bit error; a differential metric computing section for computing a differential metric based on the binary signal of the extracted state transition pattern; an error computing section for computing an error rate predicted based on an integration value that is integrated by an integration section, a count value that is counted by a pattern count section, an integration value that is integrated by another integration section, and a count value that is counted by another pattern count section, and a standard deviation computing section for computing a standard deviation based on the computed error rate.

Abstract: A reproduction signal evaluation method according to the present invention relates to adjustment of an edge portion between a shortest mark and a shortest space in a data sequence including marks and spaces in combination that is recordable on an information recording medium. In a pattern including a shortest mark and a shortest space adjacent before or after the shortest mark, a shift amount of an edge of the shortest mark is obtained from a differential metric calculated regarding one of a first pattern in which a space adjacent to the shortest mark and not adjacent to the shortest space is longer than the shortest space; and a second pattern in which a mark adjacent to the shortest space and not adjacent to the shortest mark is longer than the shortest mark.

Abstract: A reproduction signal evaluation method evaluates the quality of a reproduction signal reproduced from an information recording medium based on a binary signal generated from the reproduction signal using a PRML signal processing system. A pattern extraction step extracts, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step computes a differential metric based on the binary signal; an extraction step extracts the differential metric which is not greater than a predetermined signal processing threshold; a step determines a mean value of the differential metrics which are not greater than the signal processing threshold and extracted in the extraction step; a standard deviation computing step determines a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step evaluates a quality of the reproduction signal using the standard deviation.