Abstract: A recording and reproducing apparatus includes a light source to emit a laser beam, an information light beam irradiation unit to irradiate a medium with an information light beam, a reference light beam irradiation unit to irradiate the medium with a reference light beam so as to form a specific speckle pattern on the medium. The reference light beam irradiation unit comprises a diffusion board provided in the way of a light path through which the laser beam is passed and generating the reference light beam, a rotation controller to rotate the diffusion board, and an identification information detector to detect identification information previously formed on a surface of the diffusion board. The diffusion board comprises a plurality of encode storage regions in which different identification information is formed and a plurality of diffusion pattern generation regions specified by the identification information.

Abstract: This invention is a holographic recording medium including a track in which position information to specify a recording position and a reproducing position of page data is formed. The position information of the track is formed of position detection patterns. The position detection patterns each including a first detection mark row including center pits arranged at predetermined intervals; and a second detection mark row including side marks arranged at the same intervals as the intervals of the center pits, the side marks having lengths substantially corresponding to integral multiples of the intervals of the center pits. The second detection mark row is arranged adjacent to the first detection mark row such that both ends of the side marks are arranged so as to correspond to the center pits in a track width direction, and page data is recorded and reproduced on the basis of positions of the center pits or positions of the ends of the side marks.

Abstract: A recording and reproducing apparatus includes a reproduction signal detection unit reproducing a two-dimensional pattern previously recorded on a holographic recording medium or user data recorded on the holographic recording medium, a reference pattern storage unit previously storing a reference pattern to be provided when the two-dimensional pattern is reproduced, a correction information generation unit comparing a reproduction reference pattern signal corresponding to the reproduced two-dimensional pattern with the stored reference pattern and removing fixed distortion contained in the reproduction reference pattern signal to generate correction information used for reproducing the reference pattern from the reproduction reference pattern signal, a correction information storage unit storing the correction information, and a distortion correction unit performing a correction calculation for a reproduction data signal using the correction information to generate corrected reproduction data from which the

Abstract: A holographic recording medium according to the present invention includes a holographic material layer in which information is to be recorded by irradiating the same region with information light corresponding to the information to be recorded and reference light to read the recorded information. The holographic material layer is divided into a plurality of recording zones by a plurality of light shielding walls. The light shielding wall is formed of a material which does not transmit bleaching light to be applied to the recording zone in which a recording process has been performed and the recorded information is to be fixed.

Abstract: It is an object of the present invention to provide a phase difference correction apparatus and a data reproduction apparatus including a data header detection apparatus that can synchronize the phase between a clock for reproducing data and an optimum sampling point of a reproduction signal with high accuracy and thus precisely detect a header of reproduced data even in a case where the S/N ratio of a signal is low.

Abstract: A holographic recording medium according to the present invention includes a holographic material layer in which information is to be recorded by irradiating the same region with information light corresponding to the information to be recorded and reference light to read the recorded information. The holographic material layer is divided into a plurality of recording zones by a plurality of light shielding walls. The light shielding wall is formed of a material which does not transmit bleaching light to be applied to the recording zone in which a recording process has been performed and the recorded information is to be fixed.

Abstract: A holographic recording medium is a medium which records and reproduces data by irradiation with an information beam and a reference beam. This medium includes a user region for recording user data; and a calibration region for storing calibration data for calibrating an element which determines a recording and reproducing characteristic of a recording and reproducing apparatus for recording and reproducing data on/from the recording medium. The calibration data stored in the calibration region includes pattern information for measuring the element determining the recording and reproducing characteristic of the recording and reproducing apparatus.

Abstract: A reproducing apparatus for an optical recording medium, comprising: a reference beam irradiator for irradiating an optical recording medium on which information is recorded by holography with a reference beam to generate a reproduction beam; a two-dimensional image pickup device capable of being partially read, which receives the reproduction beam; a partial reading controller for controlling partial reading of information on the two-dimensional image pickup device; and an information processor for performing a predetermined process by using the information to be partially read.

Abstract: A recording and reproducing apparatus according to the present invention includes a light source for emitting a light beam, a spatial modulating part for modulating the light beam to create information light, using spatial information associated with page data A to be recorded on a holographic recording medium, an optical-path changing part for changing an optical path of the information light created by the spatial modulating part, a light detecting part for receiving the information light having the optical path changed by the optical-path changing part, and a diagnosis part for inspecting operations of recording and reproducing components including the spatial modulating part and the light detecting part, using the page data A and page data B obtained from the information light received by the light detecting part.

Abstract: An optical recording medium which comprises a holographic recording layer on which information is recorded by means of holography, a light shield member fixed to at least one of main surfaces of the holographic recording layer, a control electrode for controlling a light transmission state of the light shield member, wherein, the light shield member has a plurality of pixels obtained by dividing the light shield member on a recording unit region basis, and the light transmission state can be controlled pixel by pixel.

Abstract: A data signal processing apparatus is capable of reproducing original data with a small number of repetition times of an iterative decoding process, which is realized by likelihood information operating means that generate updated likelihood information, carry out a predetermined operation on a plurality of pieces of likelihood information corresponding to the original data obtained by the iterative decoding process, and reproduce the original data.

Abstract: It is an object of the present invention to provide a data reproducer in which the quality of a reproduction signal is improved. A data reproducer of the present invention includes a phase-difference detecting section which obtains the cross correlation value between the head pattern in a track to be reproduced and a reproduction signal, synchronous detectors which respectively obtain the cross correlation value between the head pattern of a track adjacent to the track to be reproduced and the reproduction signal, and crosstalk value detector which obtains the direction and ratio of crosstalk in accordance with these cross correlation values. The data reproducer has a correcting function which corrects the offset and gain of a reproduction signal in accordance with a phase difference and cross correlation value obtained by the phase-difference detecting section.

Abstract: Crosstalk cancellation is realized more accurately than ever by considering both magnitude and a phase difference of a crosstalk signal from a recording track adjoining a target track, in comparison with magnitude and a phase of a desired signal from the target track, which is implemented by providing a crosstalk amount detection means, a phase difference measurement means, and a crosstalk component generation means that generates a crosstalk component to be subtracted from a signal obtained by an optical scanning that includes the desired signal and the crosstalk.

Abstract: It is an object of the present invention to provide a phase difference correction apparatus and a data reproduction apparatus including a data header detection apparatus that can synchronize the phase between a clock for reproducing data and an optimum sampling point of a reproduction signal with high accuracy and thus precisely detect a header of reproduced data even in a case where the S/N ratio of a signal is low.

Abstract: An optical disk includes a recording area divided into annular bands and further into sectors. Each sector includes alternating grooves and lands, both serving as data-recording tracks. Each groove includes an address region in which data is recorded by in-phase double wobbles. The address region includes an address selection data recording portion and individual address data recording portions. The address selection data recording portion stores data for selecting one of the individual address data recording portions to read individual address data from the selected recording portion.

Abstract: In an apparatus for reproducing recorded data, a crosstalk signal is generated by converting adjacent data recorded on an adjacent track into a waveform of said reproduction signal and the crostalk signal is deducted from the reproduction signal. Then, the reproduction signal in which the crosstalk signal is eliminated is decoded in accordance with the predetermined algorithm and reproduced.

Abstract: A data reproduction device for sampling a signal reproduced from a recording medium based on a synchronization clock signal synchronized with the reproduced signal includes: an analog-to-digital conversion part converting the reproduced signal into a first digital signal based on a first clock signal; an interpolation part interpolating the first digital signal so that the first digital signal is equalized with a second digital signal sampled based on a second clock signal having a frequency n times the frequency of the first clock signal; an optimum phase detection part receiving the output of the interpolation part and detecting the phase error between the optimum point of the reproduced signal and the synchronization clock signal; a phase correction part correcting the phase of the reproduced signal based on the phase error; and an information data start detection part detecting the start of information data based on the phase error.

Abstract: A data signal processing apparatus is capable of reproducing original data with a small number of repetition times of an iterative decoding process, which is realized by likelihood information operating means that generate updated likelihood information, carry out a predetermined operation on a plurality of pieces of likelihood information corresponding to the original data obtained by the iterative decoding process, and reproduce the original data.

Abstract: Crosstalk cancellation is realized more accurately than ever by considering both magnitude and a phase difference of a crosstalk signal from a recording track adjoining a target track, in comparison with magnitude and a phase of a desired signal from the target track, which is implemented by providing a crosstalk amount detection means, a phase difference measurement means, and a crosstalk component generation means that generates a crosstalk component to be subtracted from a signal obtained by an optical scanning that includes the desired signal and the crosstalk.

Abstract: In an apparatus for reproducing recorded data, a crosstalk signal is generated by converting adjacent data recorded on an adjacent track into a waveform of said reproduction signal and the crostalk signal is deducted from the reproduction signal. Then, the reproduction signal in which the crosstalk signal is eliminated is decoded in accordance with the predetermined algorithm and reproduced.