Rca Inc.

Leonard P Fox

Pabitra Datta

Istvan Gorog

Dennis Lee Matthies

Richard William Nosker

Hirohisa Kawamoto

Louis A DiMarco

Frederick L Dixon

Edward G Trachman

A video disc comprises a grooved disc having video information in the form of a surface relief pattern within the groove, the disc made from a plastic material containing finely divided conductive particles such that the bulk resistivity at 900 MHz is less than 500 ohm-centimeters.

Conductive video disc

A high density capacitive information disc recording medium fabricated from a conductive plastic molding composition including a moldable plastic and conductive carbon black particles having a volatiles content at 950.degree. C. of less than about 1 percent.

Conductive molding composition and discs therefrom

In accordance with the present disclosure recorded metallic recording substrates made of a relatively soft metal are coated with a conformal 200 to 400 angstroms thick layer of chromium, chromium oxide, or a mixture thereof, and then preferably passivated prior to being used as matrixes in the replication process.

Method for the manufacture of a metallic recording substrate for a

A pad for wiping the surface of a high-density information disc wherein information is recorded in a groove on the surface of the disc, comprises a plurality of fibers, projecting from a backing element and having ridged outer surfaces. The diameter of each of the fibers is greater than the width of the groove, while the width of at least some of the ridges is narrower than the width of the groove. One wiping method involves manually bringing the pad's fibers into contact with the grooved surface of the disc while establishing relative motion therebetween. In an alternative method, the wiping function is automatically implemented in a disc player by means mounted on the player lid for bringing the pad's fibers into and out of contact with the grooved surface of a disc carried by a rotating turntable, responsively to the travel of a signal pickup carriage.

Wiping apparatus and method for a high-density information record

A method of forming a disc having an information recording groove of regular cross-sectional shape by forming a preliminary spiral groove of trapezoidal cross-section in a disc having a relatively flat surface, and then flowing an excess of viscous material on the groove surface of the disc while rotating the disc rapidly and long enough to flow off the excess viscous material so as to leave a continuous coating of viscous material over the surface of the disc, the trapezoidal regions being covered by a coating having a relatively constant radius of curvature.

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Cherry Hill, NJ, United States of America

Leonard P Fox