Abstract: A disc-shaped record carrier is described on which information is recorded in an optical structure of trackwise arranged areas and intermediate areas. By adapting the average dimensions of the areas to the average spatial frequencies on the record carrier a read signal can be obtained of sufficient modulation depth and minimal distortion. This is accomplished by increasing the track width with decreasing radius of the record carrier.

Abstract: A mother for manufacturing long-playing video records is provided by (1) selectively exposing a photoresist disposed as the outer layer on a substrate comprising a disc-shaped plate, a thin layer of base material, e.g., an oxide of nitride, adhering to the plate and a thin metal layer, e.g., chromium, silver, nickel or titanium, coating the base material layer, (2) removing non-activated sections of the photoresist layer and (3) sputter or chemically etching the thin metal and base material layers in sections corresponding to the removed sections of the photoresist layer.