Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Patent
1998-04-27
2000-11-28
Edun, Muhammad
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
369112, G11B 700
Patent
active
061544329
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to an optical storage system incorporating a compact optical storage means and an optical head. In particular it relates to a holographic optical storage card able to store large amounts of data in a relatively small area and a read/write/erase head for use with the storage card.
BACKGROUND TO THE INVENTION
Current electronic parallel computers are capable of processing data at rates well into the GFLOP range. These peak rates can be achieved only when the data involved reside in the main memory of the system and can be transferred to the processing units at high speeds.
This is typically the case with numerically intensive problems such as scientific simulations and floating point calculations. A different class of problems, known collectively as non-numerical processing, includes data and knowledge base management, logic inferencing, image processing, machine vision, computer-generated holographic storage, and document retrieval. These applications are input/output intensive and rely on the computer's ability to process a vast amount of data which cannot fit in main memory but must be retrieved from secondary storage.
Therefore, the performance of the secondary memory system becomes critical and is usually determined by two factors: storage capacity (in Mbytes) and data transfer rates (in Mbytes per second). Both of these quantities must be as high as possible. In order for storage devices to keep up with the constant increase in database volumes, they must allow access to Terabytes of data in a relatively short time.
With existing technology the most inexpensive means of storing information is magnetic storage. Magnetic storage allows the storage of large amounts of data but has a number of limitations. Magnetic or electric fields can erase or corrupt the data, the storage medium can be tampered with, and the read/write process limits the data transfer rate achievable.
Optical storage media based on holographic data storage have greatly increased the amount of data which can be stored as well as improving security and data access time. The most common application of this technology is in audio or video compact disks.
The audio CD was introduced jointly by Philips and Sony in 1982. It stores digital bits as pits (or the absence of pits) impressed in its reflective surface along concentric tracks. Transparent plastic protects the surface, which is scanned by the beam of a solid-state laser having a 780-nm wavelength. The audio CD stores 640-680 MB of information, or about 74 minutes of music, assuming standard sampling rate, frequency, and encoding.
Two computing proposals for high-density disks have been announced: the Sony/Philips MultiMedia CD (MMCD) and the Toshiba/Time Warner Super-Density (SD) disk. As currently proposed, the latter is a two-layer disk that can hold 3.7 GB on a single layer, for a total capacity of 7.4 GB. The proposed SD disk stores 5 GB on each side, for a total of 10 GB.
Storage capacities on compact disc systems are large and thus very useful but limited by the mechanical parts and, to some extent, by the cost. Furthermore, the majority of known holographic data storage systems are read only. Such systems include CD ROM and WORM (write once read many).
Among various other storage systems, three-dimensional (3-D) optical memories, such as volume holograms and two-photon memories, appear very attractive. Holographic storage offers large digital storage capacity, fast data transfer rates, and short access times. Current storage technologies are limited in that they do not simultaneously provide each of these three features.
Erasable devices based on thermoplastic have been developed quite recently. One such device is that described in EP 256554 in the name of Teijin KK This patent describes a thermoplastic substrate for use in optical memory cards. The patent details a laminated card structure having defined lamination thicknesses to improve image contrast.
A random access optical memory device has been described by Uban and Urban i
REFERENCES:
patent: 4737745 (1988-04-01), Eich et al.
patent: 4837745 (1989-06-01), Eich et al.
patent: 5148421 (1992-09-01), Satoh et al.
patent: 5311474 (1994-05-01), Urban
patent: 5319629 (1994-06-01), Henshaw et al.
patent: 5450378 (1995-09-01), Hekker
patent: 5489451 (1996-02-01), Omeis et al.
patent: 5978112 (1999-11-01), Psaltis et al.
"Spiropyran-doped poly(vinyl carbazole): a new photopolymer recording medium for erasable holography," Fatema Ghailane, et al., Feb. 1995, pps. 480-485, Optical Engineering.
Faruqi Farhan Ahmed
Martin Donna Kourtessis
Edun Muhammad
Yenploy Pty Ltd.
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