Methods of detecting counterfeit or authentic optical and/or audio discs

#This invention relates to novel, quick, and reliable detection methods for determining the authenticity of optical and/or audio disc articles (such as compact discs, digital video discs, CD-ROM discs, and the like). Such a method basically entails the incorporation of an identifier or marking means within the edges of target optical discs or within any other portion of a target disc such that exposure to non-visible light sources will provide the desired identification upon irradiation or detection of the marking means therein. Such an identifier or marking agent thus may be utilized in conjunction with a transparent holding case whereby the optical discs may be exposed through the transparent walls thereof to permit detection of counterfeit or authentic discs without requiring opening of the case itself. Such a method may also be utilized for discs that are removed from or have not been placed and sealed within such a case as well. Specific methods of utilizing particular transparent cases are thus also encompassed within this invention as are novel storage unit configurations to maximize the benefits of the transparent properties thereof.

#Optical data storage discs, such as compact discs (CDs), digital video discs (DVDs), and compact discs having read-only memory (CD-ROMs), have been utilized within the entertainment and computer field for a number of years, with DVDs recently entering the market with much higher amounts of available encoded information for more impressive video results. Such discs generally comprise a layer of plastic material, on one side of which is formed a micro-relief pattern in the form of indentations which comprise an encoded information signal. This information-containing side exhibiting such a micro-relief pattern is then provided with a lacquer-protected metallized reflective layer to permit reading via a laser sensor. DVDs may contain more than one such layer of micro-relief patterns thus providing increased amount of information. Such DVDs exhibit several formats but always comprise two substrates, each formed with at least one information layer, that are secured to one another. Furthermore, the lacquered portion of the disc, generally being solely on one side, usually is provided with visible printed information for identification, informational, and/or aesthetic purposes to the user. Standard and particular production methods for such discs are disclosed within such documents as U.S. Pat. No. 6,165,391 and European Patent EP 0608358B1 (including the production of discs including holographic images embossed in the lacquer forming the protective layer for the metallized surface in order for the micro-relief pattern to define such an holographic image).

#Such optical discs are normally formed from polycarbonate material which is injected into an injection molding machine in which a stamper is present, the stamper forming the pattern of indentations in the subsequently formed disc to provide the encoded signal. Other techniques utilize compression molding with a specific mold to provide the encoded signals therein.

#The present invention will now be described in more detail by way of example only, with reference to the accompanying drawings wherein:

#FIG. 1 is a cross-sectional view of a compact disc.

#FIG. 2 is a top view of the inventive movable rosette arm storage unit configuration.

#Referring now to FIG. 1, an optical disc is shown which comprises a plastic substrate 10 normally formed from polycarbonate, preferably comprising either at least one iridescent compound, such as an Ultraviolet tag (what type?) which illuminates at the peripheral edge 8 when exposed to an ultraviolet light source, or a bar-code stamped into the peripheral edge 8, or a holographic image present at the peripheral edge 8, the upper surface 11 having a pattern of pits formed therein which define a data recording. The pitted surface 11 is provided with a metallic film 12 so as to provide a light reflecting surface, the metallic layer 12 being covered by a protective layer of lacquer 13 which may be an ultraviolet light curable resin such as that sold under the trade mark RENGOLUX®.

#The resin is normally applied to the disc by spin coating, i.e. the resin is applied to the disc at a position slightly radially inwardly from the radially innermost extremity of the metallized surface, the disc being rotated at speed, such that the resin flows towards the circumference of the disc, and is cured by exposure to ultraviolet light.

#The manner in which the polycarbonate substrate 10 is formed is normally by injection molding. A metal plate known as a stamper having a surface formed with an information layer is placed in the cavity of an injection mould and polycarbonate material is injected into the mould.