Method for forming a narrowed-electrode pickup stylus for video disc systems

A method of fabricating a narrowed-electrode stylus by modifying a tapering dielectric support element having a tip which is defined by a prow and a substantially flat V-shaped rear surface remote from said prow;

• the entire rear surface of said dielectric support element being covered with conductive material to form an electrode;
• said narrowed-electrode stylus being suitable for playing back prerecorded signals from a disc record groove of a given width and a given pitch;
• said method comprising the steps of:
• introducing said tip of said tapering support element in an abrasive groove having a bottom wall, substantially parallel side walls separated by a distance less than said given width and lands extending away from said side walls;
• while
• establishing relative motion between said tapering support element and said abrasive groove along a line which is disposed in a plane substantially perpendicular to said V-shaped rear surface;
• gently tilting said electrode face of said support element toward said abrasive groove until it subtends a shallow angle with the bottom wall of said abrasive groove to form a portion having an arrowhead-shape cross-section in the region of said tip;
• the apex of said arrowhead-shape cross-section being located on said prow;
• the base of said arrowhead-shape cross-section being defined by said substantially flat rear surface;
• said lands of said abrasive grooves forming the shoulders of said arrowhead-shape cross-section;
• said side walls of said abrasive groove forming the sides of said arrowhead-shape cross-section interconnecting said shoulders and said base of said arrowhead-shape cross-section;
• and
• terminating said relative motion subsequent to formation of said tip portion having an arrowhead-shape cross-section.