85results about "Holographic discs" patented technology

A method for irradiating a medium with a wave which is designed to focus on a particular portion in the medium, the method includes: irradiating the medium with an electromagnetic wave which is scattered in the medium, and is not designed to focus on the particular portion in the medium; detecting a first signal caused by irradiating the medium with the electromagnetic waver; irradiating the medium with a reconstructed wave which is designed to focus on the particular portion in the medium; detecting a second signal caused by irradiating the medium with the reconstructed wave; and monitoring, based on the first and second signals, that the particular portion is irradiated by the reconstructed wave.

An apparatus and method for processing optical information using a low density parity check code are suggested. An optical information recording method includes the steps of encoding data to record into a low density parity check code; representing the data, which is encoded into the low density parity check code, to a spatial light modulator in the unit of a data page; and modulating a recording beam into the data page representing the spatial light modulator to be recorded in the form of hologram in a recording medium. By blocking inexact probability information from being concentrated in the LDPC code block, by achieving exact probability information through effective allocation of a mark, and by improving average accuracy of the pixel, which corresponds to the LDPC code, failure rate of decoding can be minimized so that decoding performance can be improved.

Systems and methods for constructing low-density parity check codes for holographic storage are provided. The methods include selecting parameters of a low-density parity check code, determining the number of bit processing elements and the amount of memory in an accompanying decoder, and constructing a mother matrix representation of a quasi-cyclic parity check matrix. The low-density parity check codes are optimized for performance, memory considerations, and throughput.

The present invention provides systems and methods for logically organizing data for storage and on a data storage medium using a multi-level format. The present invention also provides systems and for protecting data stored on data storage medium so that the data may be recovered without errors.

Holographic recording drives encode data for recording into a holographic medium. The steps comprise run length limited encoding three bytes of data into 5×5 matrix information, the data subject to a 4-byte error correction code; and providing the 5×5 matrix information to a spatial light modulator (SLM), as a portion of a two-dimensional pixel matrix of the spatial light modulator, for recording into a holographic image on the holographic medium.

Hologram recording and reconstruction apparatuses and method thereof are provided. The hologram recording apparatus comprises a laser source, a spatial light modulator, and a Fourier lens. The laser source provides a coherent light beam. The spatial light modulator receives m-bits data to only determine a (pxq) block comprising ON-pixels less than OFF-pixels, and receives the coherent light beam to modulate with the (pxq) block to generate the signal beam. The Fourier lens focuses the signal beam on the hologram recording medium, so that when the focused signal beam and a focused reference beam is modulated together, the hologram data is generated to be recorded on the hologram recording medium.

A recording and reproducing device includes: a reference light irradiating section; a spatial light modulating section for generating information light; an information light irradiating section for irradiating the same region as a region irradiated with the reference light, with the information light; a light detecting section for receiving reproduction light; a known data storage section; a defect examining section for examining a defective position of the spatial light modulating section or the light detecting section by irradiating the information light and the reference light to write the known page data to the holographic recording medium, and then irradiating the medium with the reference light to read the known page data written on the holographic recording medium from the reproduction light received by the light detecting section; and a reproducing control section for restoring and reproducing the original data of the defective position using information of the defective position detected by the defect examining section.

There is provided an optical information detecting method. The method includes: detecting an image of a source data page coded with balanced codewords by the use of 1:N (where N is greater than 1) excessive detection pixels; determining a distribution pattern of valid detection pixels and invalid detection pixels to be corrected in the detected image by the use of a light intensity distribution of the detected image; and dividing the detected image into balanced codeword detecting areas corresponding to the balanced codewords and sampling data of the balanced codeword detecting areas by the use of the determined distribution pattern and an optical distribution characteristic of the balanced codewords. Accordingly, it is possible to efficiently detect optical information by the use of a 1:N over-sampling method. Specifically, the distribution pattern of valid detection pixels and invalid detection pixels in the detected image of a data page can be properly used to sample a balanced code.

A method is provided for monitoring degradation of a data storage medium. Multiple reactive elements are provided in the data storage medium. Properties of each one of these elements is determined, prior or subsequent to data being stored in the medium, to generate a baseline map of the medium. Updated properties of at least one of the elements are determined in order to generate an updated map of the medium. A determination can then be made as to whether degradation of the medium has occurred by comparing the baseline map to the updated map.

A portable data storage cartridge comprising a housing, a first information storage medium removeably disposed within the housing, a holographic data storage medium disposed within the housing, wherein the housing is formed to include an aperture, and wherein the holographic data storage medium is disposed adjacent the aperture.