Optical disc structure having an air sandwich structure

摘要

In an optical disc structure for information recording comprising two discs in the form of an annular coaxial plate having optical recording thin layers of one surface thereof, the discs being melt-adhered by ultrasonication via annular coaxial sealing members composed of an outer annular spacer and an inner annular spacer to form an air sandwich structure so that the optical recording thin layers face each other through an air space, provided that one of the optical recording thin layers may be omitted. The sealing members and said discs are formed of a copolymer of ethylene. The ethylene copolymer forming the sealing members has an ethylene content (a) of 55 to 80 mole % and the ethylene copolymer forming the discs has an ethylene content (b) of 50 to 70 mole %, where (a) is larger than (b).