Heatable and coolable press mould - made of high compressive strength glass for thermoplastic video discs and other plate-like information carriers

摘要

Plate-like information carriers, made of thermoplastic materials, for high-density optically scanned video or image discs, are produced in presses with moulds in which a cooling and a heating system are incorporated. The block mould is made of glass with a high compressive strength in which ducts for a coolant are enclosed. Heating wires are embedded close to the ace which carries the matrix with the surface structure for the information carrier. The glass surfaces can be ground to a surface roughness of 0.2 u which results in lesser scanning errors than when steel moulds are used.