Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-09-29
2004-06-08
Edun, Muhammad (Department: 2655)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S047100, C369S084000
Reexamination Certificate
active
06747930
ABSTRACT:
FIELD OF INVENTION
The present invention broadly relates to data storage media for use with optical scanning machines, which data storage media are adapted to limit access to information stored thereon. More particularly, the present invention concerns optical disks for use in an optical readout system of a computer to limit continual or repeated unrestricted access to stored data by the optical readout system. A method is also provided for limiting access to data stored in an optical medium environment.
The present invention also relates to a data storage device that provides high data storage capabilities and is easily carried by a user in that the device can be approximately the size of a credit card. In particular, the present invention can be used with both conventional magnetic card swipe readers and optical disk readers. Thus, in one embodiment, the present invention may be viewed as a combination of a typical credit card with a (magnetic or optical) strip that is read via swiping the present invention through a card swipe reader and an optical disk such as a mini compact disc (e.g., DVD).
BACKGROUND OF THE INVENTION
The computer industry has long been plagued by the illegal misappropriation of software products. The Software Publisher's Association (SPA), an organization with devotes significant resources to tracking and analyzing piracy problems, has determined that in 1994 alone the personal computer software industry lost in excess of $8 billion due to illegal copying of business application software. The SPA further estimated that virtually half of the business software in use in 1994 was pirated, and this estimate does not include the illegal copying of operating systems, education, entertainment or personal productivity software. The piracy problem is particularly acute in more developed markets such as the United States.
Many approaches have been implemented by software producers in an effort to combat piracy. Some of these approaches include encryption, special data formatting complex installation procedures, and passwords, to name only a few. Unfortunately, end user resistance to these anti-piracy schemes has been high because they are plagued by one or more limitations, such as an inability to “try before you buy”, restrictions on the generation of legitimate back-up copies, and password protection techniques which fail once the password is divulged or discovered. The inability of copy protection schemes to win end-user acceptance has been so extreme that many publishers have simply abandoned the effort, choosing instead to rely on the integrity of their customers to abide by copyright laws.
The misappropriation of software is rampant irrespective of whether the data storage medium is magnetic or optical. Magnetic storage disks are particularly susceptible to piracy. Commercially available magnetic disks, such as the conventional floppy disk, are read/write/erase memory devices in which data is stored in a magnetizable surface layer as discrete patterns of magnetism. Information is stored and retrieved by a read/write head which contains a coil wound around an iron core.
While the magnetic recording medium remains the most popular, there has been a growing trend in recent years to utilize an optical medium environment for the storage and retrieval of data. The reason for this trend is readily apparent. A commercially available magnetic floppy disk is only capable of storing 1.44 Mb of data, whereas an optical CD-ROM of the same size can have a capacity in excess of 600 Mb.
In a typical optical disk for use in a computer's optical readout system, data is stored as a series of lands and pits. This is accomplished by stamping along spiral tracks on a transparent plastic disk, overlaying this with a reflective coating, and thereafter superimposing a protective layer over this coating. Light from a semi-conductor laser is focused onto either the lands or pits from below and the reflected light impinges upon a photodetector which converts the presence or absence of the pits into a binary electrical signal. Because the focused laser spot is so minute, the amount of information that can be stored onto the surface of the disk is immense. Adjacent tracks need only be spaced apart by approximately 0.6 &mgr;m and, hence, 20,000 tracks may be available on a conventional 120 mm diameter (5 inch) optical disk. The electrical signals delivered to the optical readout system correspond to the magnitude of the reflected light which either increases or decreases due to interference and/or diffraction by the preformatted data structures.
In the 1970's, researchers began attempting to encode information on optical disks with lasers, and the video disk was subsequently developed. In the 1980's, more sensitive materials that could be encoded with a low power diode laser were developed. These diode lasers, operating at a wavelength of approximately 800 nm, are now universally employed to read audio and computer CD's. Following the advent of compact disks which are capable of being read with a laser diode, researchers have now endeavored to develop a marketable compact disk upon which data can be recorded by an end user. The benefit of this capability, as discussed above, is that optical laser recording provides a much higher information density than magnetic recording.
Presently, there is a write once and read many times (WORM) compact disk. This compact disk utilizes a dye that irreversibly changes state when exposed to a high power laser diode and maintains this state when read with a low power reading laser. As such, detection of the encoded data by the optical readout system does not affect the encoded data.
It is anticipated that the next generation of optical disks will be capable of being written on, read, erased and rewritten on, etc. many times, similar to a magnetic disk. A photochromic material, or chromophore, is attractive for this purpose. Photochromism is the phenomenon whereby the absorption spectrum of a molecule or crystal changes reversibly when the material is irradiated by light possessing certain wavelengths. Thus, for example, a colorless compound may change its molecular state to a quasi-stable colored state when radiated by ultraviolet (UV) light, yet be returned to the colorless state upon exposure to visible light. Both organic and inorganic materials which exhibit these properties have been known for years.
Recently, photochromic compounds have attracted much attention in the field of optical recording. As discussed in Jun'Etsu Seto,
Photochromic Dyes
, the photochromic materials initially studied for such an application did not have significant sensitivity in the infrared region near 800 nm, the wavelength region of conventional laser diodes. Seto recognizes, however, that a specific class of photochromic compounds, known as spiropyrans, can be manipulated to exhibit improved sensitivity in the infrared region. Specifically, Seto discusses a class of photochromic spiropyrans with benzothiopyran units in the molecular framework and concludes that the synthesized spirobenzothiopyran is well suited to the requirements of erasable optical recording media for systems using conventional laser diodes.
Another dye of the spiropyran class, having the chemical composition 6-nitro-1′3′3′-trimethylspiro[2H-1-benzothiopyran-2,2′-indoline], or 6-nitro-1-SBIPS for short, is discussed in Tarkka, Richard U., Talbot, Marc E. , et al. , “Holographic Storage in a near-ir sensitive photochromic dye”,
Optic Comm
. 109, 54-58 (1994). This article discusses the use of 6-nitro-1-S-BIPS for use in the holography field wherein the dye becomes colored when exposed to light having a wavelength of 780 nm. The film returns to a quasiclear state upon exposure to an ultraviolet light source at 337 nm.
It is anticipated, based on these recent developments, that the conventional magnetic disk will eventually become obsolete due to the recent developments in optical storage technology. Concurrent with this anticipated phaseo
Lackritz Hilary S.
McLaughlin Mark
Merry J. Bradford
Schneck, Jr. Karl R.
Smith Jerry
Edun Muhammad
Hide & Seek Technologies, Inc.
Sheridan & Ross P.C.
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