Rca Inc.

Pierre V Valembois

Hirohisa Kawamoto

Gunter John

Cheryl A Deckert

James H Rainey

Edward J Holub

Edward W Maby

A cutting stylus adapted for mechanically cutting a deep groove, which may be used in lapping the keel on a playback stylus, is provided. The stylus includes a tapering body, a constricted terminal region and shoulders joining the tapering body and the constricted terminal region. The shape of the constricted terminal region is complementary to the shape of the keel tip on the playback stylus. The terminating portion of the stylus tip has a substantially flat cutting face, a pair of side surfaces extending from the side cutting edges of the cutting face which taper at a slight angle to provide clearance to the side cutting edges, and a bottom surface extending from the bottom cutting edge of the cutting face at an angle which provides relief to the bottom cutting edge.

Cutting stylus for mechanically cutting masters for keel-lapping

In a method for determining the machinability of a metal substrate for use in an electromechanical recording apparatus a surface of a foundation is coated with a layer of metal. The metal layer is machined such that the metalized surface of the foundation is substantially flat and smooth. After the machining step, the metal surface is inspected for depressions with a microscope using a differential interference contrast technique. The number of depressions observed is indicative of the machinability of the coated foundation.

Optical inspection method for determining machinability

An improved method for fabricating a diamond video disc playback stylus. The method comprises the steps of preparing a bottom surface which contacts the video disc and producing a conductive layer adjacent to the bottom surface by ion implantation. The improvement lies in annealing the diamond at about 850.degree. to about 1500.degree. C.

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Cranbury, NJ, United States of America

Pierre V Valembois