Abstract: A multi-layer optical storage medium includes a transparent substrate, a partially reflective layer, a transparent spacer, and a highly reflective layer. One pattern of data pits is provided on the substrate, adjacent the partially reflective layer, and another pattern of pits is provided on the spacer layer, adjacent the highly reflective layer. The partially reflective layer may be made of amorphous selenium (a-Se) and preferably has an index of refraction having a real component, n, greater than 2.8 and an imaginary component, K, less than 0.01. The invention also includes the optical data storage systems compatible with such media.

Abstract: A multi-layer optical storage medium includes a transparent substrate, a partially reflective layer, a transparent spacer, and a highly reflective layer. One pattern of data pits is provided on the substrate, adjacent the partially reflective layer, and another pattern of pits is provided on the spacer layer, adjacent the highly reflective layer. The partially reflective layer may be made of antimony sulfide, such as antimony(III) sulfide, Sb2S3. The invention also includes the optical data storage systems compatible with such media.

Abstract: An optically-readable data disc includes piracy-protection featuring noncontiguously sequenced data files in zones separated by head-derailing barriers. The disc includes a plurality of data-placement zones and read-blocking barriers constructed along the spiral track over gaps which separate the zones. Data files are recorded in each of the zones, and an address-information data file includes data which identifies addresses of data files to be sequentially read in noncontiguous zones. By arranging the data files noncontiguously with barriers in gaps between the data files, efforts to duplicate the master disc by attempting to read the data files contiguously are deterred and/or prevented.

Abstract: A compact disc package made of double paneled paper board and including a base panel assembly and a cover panel assembly that are joined by an edge panel and will fold to overlie each other and to open by hinging at the edge panel. The base panel assembly formed such that the double walls of the base panel assembly are unattached in corner portions of such panel assembly and slots are provided to permit access to a space between the double walls. An insert, which is slightly smaller than the base panel assembly, is flexible such that its corner portions can be inserted through the slots into the spaces between the walls of the inner and outer base panels. The insert includes retainers for holding a compact disc in position on the base panel assembly while the cover panel assembly is hinged over the insert and a compact disc on the insert.

Abstract: A compact disc package made of paper board and including a base panel assembly and a cover panel assembly that are joined by an edge panel and will fold to overlie each other and to open by hinging at the edge panel. The base panel assembly is formed with an outer base panel and two inner base panel sections that fold inwardly from opposite edges of the outer base panel and form pockets for receiving an insert for a compact disc. The insert is flexible such that its corner portions can be inserted through the slots into the pockets formed panel. The insert includes retainers for holding a compact disc in position on the base panel assembly while the cover panel assembly is hinged over the insert and a compact disc on the insert.