STRUKTUR EINER OPTISCHEN SCHEIBE MIT ZWISCHENRAUM ZWISCHEN DEN AUFZEICHNUNGSSCHICHTEN.

摘要

An optical disc structure for information recording comprising two discs (1,1 min ) in the form of an annular coaxial plate having optical recording thin layers (2,2 min ) on one surface thereof, said discs (1,1 min ) being melt-adhered by ultrasonication via annular coaxial sealing members composed of an outer annular spacer (3) and an inner annular spacer (3 min ) to form an air sandwich structure so that the optical recording thin layers (2,2 min ) face each other through an air space (4), provided that one of the optical recording thin layers (2,2 min ) may be omitted, wherein� (I) said sealing members (3,3 min ) and said discs (1,1 min ) are formed of a copolymer of ethylene with a comonomer of formula (1) �� wherein R<1> to R<1><2>, independently represent hydrogen, halogen or C1-C4 alkyl and R<9> and R<1><0> may be bonded to R<1><1> or R<1><2> to form a trimethylene or tetramethylene group, n represents 0, 1, 2, or 3, and when n represents 2 or 3, two or three of each of R<5> to R<8> groups may be identical or different, and (II) a said copolymer (A) forming said sealing members (3,3 min ) has an ethylene content (a) of 55 to 80 mole%, a said copolymer (B) forming the disks (1,1 min ) has an ethylene content (b) of 50 to 70 mole%, and (a)>(b).