US 8,339,921 B2 · Optical information recording apparatus, optical information recording method, optical information recording/reproducing apparatus and optical information recording/reproducing method

Abstract

An optical information recording/reproducing apparatus using holography comprises a signal generation unit that modulates input data, adds at least one control bit to each group of N bits, performs an NRZI-modulation on the modulated data, determines the at least one control bit such that a digital sum value of the NRZI-modulated data is 0, performs NRZI modulation on the data whose at least one control bit was determined, and rearranges the data to generate 2-dimensional data; a pickup that records the 2-dimensional data in a hologram disc and reproduces the 2-dimensional data from the hologram disc; and a signal processing unit that corrects the 2-dimensional data reproduced by the pickup, performs NRZI-modulation on the 2-dimensional data that has undergone a binarization operation, removes the at least one control bit added during the recording, and demodulates the data according to a modulation rule used during the recording.

Claims18

Dependent claims

An optical information recording apparatus to record information in a holographic memory, the optical information recording apparatus comprising;

a laser light source generating a signal beam and a reference beam;
a signal generation unit adding at least one control bit to an input data and generating a first 2-dimensional page data;
a spatial light modulator adding the first 2-dimensional page data to the signal beam;
and
a control unit controlling the laser light source, the signal generation unit, and the spatial modulator so as to record the information by irradiating the signal beam that is added to the first 2-dimensional page data by the spatial light modulator and the reference beam in the holographic memory,
wherein the signal generation unit adds the at least one control bit so as to keep a ratio of a number of pixels of a first brightness of the spatial light modulator to a number of pixels of a second brightness that is larger than the first brightness in the first 2-dimensional page data equal to a ratio of the number of pixels of the first brightness of the spatial light modulator to a number of pixels of the second brightness in a second 2-dimensional page data that is different from the first 2-dimensional page data, the first 2-dimensional data and the second 2-dimensional data being recorded in the holographic memory.

3 more elements

An optical information recording apparatus to record information in a holographic memory, the optical information recording apparatus comprising:

a laser light source generating a signal beam and a reference beam;
a signal generation unit adding at least one control bit to an input data and generating a first 2-dimensional page data;
a spatial light modulator adding the first 2-dimensional page data to the signal beam;
and
a control unit controlling the laser light source, the signal generation unit, and the spatial modulator so as to record the information by irradiating the signal beam which is added to the first 2-dimensional page data by the spatial light modulator and the reference beam in the holographic memory,
wherein the signal generation unit adds the at least one control bit so as to keep a ratio of a number of pixels of a first brightness of the spatial light modulator to a number of pixels of a second brightness that is larger than the first brightness in the first 2-dimensional page data equal to a ratio of the number of pixels of the first brightness of the spatial light modulator to a number of pixels of the second brightness in a second 2-dimensional page data that is different from the first 2-dimensional page data, the first 2- dimensional data and the second 2-dimensional data being recorded in the holographic memory, and
wherein the signal generation unit adds the at least one control bit so that a number of pixels of the first brightness of the spatial light modulator is larger than a number of pixels of the second brightness that is larger than the first brightness in the first and second 2-dimensional page data.

4 more elements

An optical information recording method to record information in a holographic memory, the method comprising:

generating a signal beam and a reference beam;
adding at least one control bit to an input data and generating a first 2-dimensional page data by a signal generation unit;
adding the first 2-dimensional page data to the signal beam by a spatial light modulator;
and
irradiating the signal beam that is added to the first 2-dimensional page data by the spatial light modulator and the reference beam in the holographic memory for recording the information;
wherein the signal generation unit adds the at least one control bit so as to keep a ratio of a number of pixels of a first brightness of the spatial light modulator to a number of pixels of a second brightness that is larger than the first brightness in a first 2-dimensional page data equal to a ratio of a number of pixels of the first brightness of the spatial light modulator to a number of pixels of the second brightness in a second 2-dimensional page data that is different from the first 2-dimensional page data, the first 2-dimensional data and the second 2-dimensional data being recorded in the holographic memory.