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 waveform shaping portion receives a digital reproduced signal generated from an analog reproduced signal reproduced from an information recording medium and shapes the waveform of the digital reproduced signal. A maximum likelihood decoding portion applies maximum likelihood decoding to the digital reproduced signal in the shaped waveform and generates a binarized signal indicating the result of the maximum likelihood decoding. A phase detection portion extracts, during the maximum likelihood decoding, a phase error using state transition patterns having only a single zero cross point among differential metrics at a plurality of merging points at which a set of paths branched from a given state merges. A synchronization detection portion generates a reproduction clock signal using the phase error that has been detected and brings the digital reproduced signal into synchronization with the reproduction clock signal that has been generated.

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: 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: 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. The method includes a pattern extraction step of extracting, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step of computing a differential metric based on the binary signal; an extraction step of extracting the differential metric which is not greater than a predetermined signal processing threshold; a step of determining 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 of determining a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step of evaluating 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: 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: A bit pattern for a run-in area which allows data reproduction to be performed stably even when the recording density of an optical disc is increased is provided. An optical disc according to the present invention includes tracks, each of which divided into a plurality of recording blocks. Each of the plurality of blocks includes a run-in area and a data area. In the run-in area, a prescribed run-in bit pattern is recordable; and in the data area, bit patterns having a plurality of bit lengths obtained by modulating data as a recording target in accordance with a prescribed modulation rule are recordable. In this optical disc, at least one of spatial frequencies corresponding to the bit patterns having the plurality of bit lengths is higher than a cutoff frequency. The run-in bit pattern recordable in the run-in area includes the bit patterns having the plurality of bit lengths, from which the bit pattern corresponding to the frequency higher than the OTF cutoff frequency has been excluded.

Abstract: The present invention aims to provide a reproduced signal evaluation method and a write adjustment method for offering a Blu-ray disc having a large storage capacity with excellent media compatibility. An evaluation index L-SEAT is calculated through signed addition using a Euclidean distance difference calculated from at least one of target signals in which a focused edge is shifted to the right and left, and the quality of the reproduced signal is evaluated based on the evaluation index. Write condition adjustment using the index enables write adjustment not depending on SNR and achieving high adjustment accuracy.

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 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: A recording control apparatus includes a waveform rectification section for receiving a digital signal generated from an analog signal representing information reproduced from an information recording medium, and rectifying a waveform of the digital signal; a maximum likelihood decoding section for performing maximum likelihood decoding of the digital signal having the waveform thereof rectified, and generating a binary signal representing a result of the maximum likelihood decoding; a reliability calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the digital signal having the waveform thereof rectified and the binary signal; and an adjusting section for adjusting a shape of a recording signal for recording the information on the information recording medium based on the calculated reliability.

Abstract: An information reproduction device according to the present invention is a device for accessing a recording medium having first address information and second address information recorded thereon. The first address information is represented by a shape formed on the recording medium in advance; and the second address information is recorded on the recording medium together with data. The information reproduction device includes a head section for accessing the recording medium to generate a reproduction signal; a first detection section for detecting the first address information from the reproduction signal; a second detection section for detecting the second address information from the reproduction signal; and a control section for, based on a detection result of either the first detection section or the second detection section which detected the address information first, controlling an access after the detection to the recording medium.

Abstract: A calculation of a reliability value |Pa?Pb|?Pstd, representing represents a maximum likelihood decoding result on a portion which corresponds to a start or termination edge of a recording mark and has a high probability of error occurrence by a maximum likelihood decoding method, is performed on each combination of a predetermined mark length and a space length immediately before the mark and each combination of the mark length and a space length immediately after the mark. Based on the calculation result, a recording parameter is optimized, and recording reflecting the optimized recording parameter is performed.

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: An address format for appropriately controlling the recording linear density and the number of information recording layers is provided in order to increase the recording capacity of an information recording medium such as an optical disc or the like in a range in which a necessary S/N ratio can be guaranteed. An optical disc includes an information recording layer having a concentric or spiral track, and has a format for describing a track address, which is pre-recorded on the track or is to be added to data that is to be recorded on the information recording layer. The format includes layer information regarding the information recording layer and address information regarding the track address.

Abstract: A big pattern for a run-in area which allows data reproduction to be performed stably even when the recording density of an optical disc is increased is provided. An optical disc according to the present invention includes tracks, each of which divided into a plurality of recording blocks. Each of the plurality of blocks includes a run-in area and a data area. In the run-in area, a prescribed run-in bit pattern is recordable; and in the data area, bit patterns having a plurality of bit lengths obtained by modulating data as a recording target in accordance with a prescribed modulation rule are recordable. In this optical disc, at least one of spatial frequencies corresponding to the bit patterns having the plurality of bit lengths is higher than a cutoff frequency. The run-in bit pattern recordable in the run-in area includes the bit patterns having the plurality of bit lengths, from which the bit pattern corresponding to the frequency higher than the OTF cutoff frequency has been excluded.

Abstract: An information processing device is a device for processing specific information recorded to a recording medium, and has a characteristic identification unit and a processing unit. The characteristic identification unit identifies the reflection characteristic of the recording medium. The processing unit processes the specific information recorded to the recording medium according to the identified reflection characteristic. The reflection characteristic is either a first characteristic such that the reflectance of light reflected by a recorded region of the recording medium (referred to as first reflectance) is greater than the reflectance of light reflected by an unrecorded region of the recording medium (referred to as second reflectance), or a second characteristic such that the first reflectance is less than the second reflectance.

Abstract: A waveform shaping portion receives a digital reproduced signal generated from an analog reproduced signal reproduced from an information recording medium and shapes the waveform of the digital reproduced signal. A maximum likelihood decoding portion applies maximum likelihood decoding to the digital reproduced signal in the shaped waveform and generates a binarized signal indicating the result of the maximum likelihood decoding. A phase detection portion extracts, during the maximum likelihood decoding/a phase error using state transition patterns having only a single zero cross point among differential metrics at a plurality of merging points at which a set of paths branched from a given state merges. A synchronization detection portion generates a reproduction clock signal using the phase error that has been detected and brings the digital reproduced signal into synchronization with the reproduction clock signal that has been generated.

Abstract: An information processing device processes specific information recorded on a recording medium, and has a characteristic identification unit and a processing unit. The characteristic identification unit identifies the reflection characteristic of the recording medium. The processing unit processes the specific information recorded on the recording medium according to the identified reflection characteristic. The reflection characteristic is either a first characteristic such that the reflectance of light reflected by a recorded region of the recording medium (referred to as first reflectance) is greater than the reflectance of light reflected by an unrecorded region of the recording medium (referred to as second reflectance), or a second characteristic such that the first reflectance is less than the second reflectance.