An optical disk reproducing device includes a division element that divides a reflected light reflected and diffracted by an optical disk into a light flux in a central region and light fluxes in end regions; a photodetector that has a central light receiver that receives the light flux in the central region and at least two end light receivers that receive the light fluxes in the end regions, and outputs a light amount signal corresponding to a light amount of each of the received light fluxes; a non-linear processor that receives each of the light amount signals from the central light receiver and the end light receivers, and outputs linear signals and non-linear signals obtained by processing the light amount signals by linear and non-linear arithmetic operations; an equalization processor that receives the linear signals and the non-linear signals and outputs signals each amplified with a predetermined gain; an adder that adds the amplified signals and outputs an equalization signal; a reproduction signal processor that processes the equalization signal and outputs a reproduction signal and an equalization error signal; and a gain controller that receives the equalization error signal and controls an amplification gain of the non-linear signals.

There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.

Provided is a reproducing apparatus including: a reproduction signal generating circuit that calculates a first difference signal which is a difference between a first light receiving signal obtained by the first light receiving element and a second light receiving signal obtained by the second light receiving element, and a second difference signal which is a difference between a third light receiving signal obtained by the third light receiving element and a fourth light receiving signal obtained by the fourth light receiving element, and uses the first difference signal, the second difference signal, a phase difference between a crosstalk component and an average phase of the signal light beam, and an optical path length difference between the signal light beam and the reference light beam to obtain a reproduction signal; and a phase extraction circuit that obtains a successive change amount and updates with a successive variation.

Amplitude or phase modulated uncompensated wobble patterns representing address patterns for track addresses of optical media are generated or applied to the media. A filter is applied to the un-compensated wobble patterns to detect a threshold value to signal the existence of a synchronization pattern. A pair of filters can be used to detect the threshold and a zero-crossing. This methodology can detect the existence and timing of the wobble pattern. This can eliminate the need for a timing recovery subfield in the wobble pattern of the prior art.

An optical recording medium includes a light-receiving surface that receives incident light and at least three information signal layers on which information signals are to be optically recorded. Among the at least three information signal layers, the information signal layer closest to the light-receiving surface has a reflectance in a range of 4% to 11%.

Provided is a reproducing apparatus including: a reproduction signal generating circuit that calculates a first difference signal which is a difference between a first light receiving signal obtained by the first light receiving element and a second light receiving signal obtained by the second light receiving element, and a second difference signal which is a difference between a third light receiving signal obtained by the third light receiving element and a fourth light receiving signal obtained by the fourth light receiving element, and uses the first difference signal, the second difference signal, a phase difference between a crosstalk component and an average phase of the signal light beam, and an optical path length difference between the signal light beam and the reference light beam to obtain a reproduction signal; and a phase extraction circuit that obtains a successive change amount and updates with a successive variation.

An optical medium reproduction apparatus for optically reproducing an optical medium, including: a detection unit for splitting a cross section of a beam returned from the optical medium into a plurality of regions and for forming respective detection signals; a multiple input adaptive equalizer having a plurality of adaptive equalizer units, wherein the respective detection signals are inputted into the adaptive equalizer units, and the outputs of the adaptive equalizer units are computed to form equalization signals; a binarization unit for binarizing the equalization signals to provide binary data; and an equalization error computing unit for determining an equalization error from equalization target signals provided based on the binary data from the binarization unit and the equalization signals, and providing the adaptive equalizer units with the equalization error as control signals for adaptive equalization.

On each of a plurality of recording layers of a write-once optical disc, two tracks constituted of adjacent land and groove are formed in a spiral shape. A writing method of data includes: a step of receiving data and a writing instruction of the data; and a step of recording management information, wherein the management information includes: virtual sequential recording range information that manages a last recorded address of the data as a virtual physical sector number; defect list that indicates a replacement correspondence relationship between the virtual physical sector number and an actually recorded physical sector number; and real next writable address information that indicates a real next writable address that is actually recordable subsequently to the physical sector number.

There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.

An information recording method of the present disclosure is an information recording method for recording information on a write-once information recording medium, including one or more recording layers, each of the recording layers being spiral-shaped on which a land track and a groove track are alternately repeated as recording tracks, each of the recording tracks being divided into blocks, each of the blocks being a minimum unit in which recording is performed. The information recording method includes: recording the information on the information recording medium in a unit of each of the blocks; and controlling recording on the information recording medium. In the control step, switching is performed whether to perform recording in a block to be recorded in which the information is to be recorded next among the blocks based on recording conditions of the recording tracks adjacent on both sides of the block to be recorded.