Video discs mass-produced by a casting process - have relatively thick plastic support layer bonded to relatively thin information layer

摘要

Video disc consists of a combination of (I) a support layer of a relatively thick flexible material, e. g. polyester film, and (II) a relatively thin information layer of a synthetic resin with a high casting sharpness e. g. a polyurethane acrylic or epoxy resin, bonded to (I) and having surface discontinuities on its outer face representing video information. The high quality video discs are easily mass produced. Specif. (II) may be coated with a very think reflecting film (III) e. g. of aluminium. (III) may be coated with a protective layer with a relatively low reflection, e.g. a transparent synthetic resin, that protects (III) against abrasion and provides a uniform flat outer surface.