Abstract: A technique for manufacturing a uniform configuration for at least two video disc styli, each stylus having a shank and a tip at one end of the shank, comprising the step of attaching an edge of a first plate of shank material to one edge of a strip of tip material different from the shank material, the strip having a face thereof oriented along a predetermined crystallographic plane. The strip is cut into the individual tips while the plate remains attached to the strip. The plate is then separated into the individual shanks to form the separate styli, whereby the orientation of the crystallographic plane with respect to the shank is uniform for all styli.

Abstract: A test disc record suitable for use in testing a capacitive playback stylus, which includes a stylus shoe which contacts a capacitive information disc record during playback and a stylus electrode which is used to recover information recorded in the capacitive information disc record by means of capacitance variations between the capacitive information disc record and the stylus electrode, wherein the test disc record includes in a major surface a continuous spiral groove which comprises an arrangement of a plurality of spiral groove turns wherein the width of a first spiral groove turn or portion thereof and signal information which can be read out by capacitance means contained in a second spiral groove turn or portion thereof which is contiguous with the first spiral groove turn or portion thereof may be used to test the width of the stylus electrode.A method and an apparatus for testing the capacitive playback stylus which employs the test disc record.

Abstract: A technique for manufacturing a uniform configuration for at least two video disc styli, each stylus having a shank and a tip at one end of the shank, comprising the step of attaching an edge of a first plate of shank material to one edge of a strip of tip material different from the shank material, the strip having a face thereof oriented along a predetermined crystallographic plane. The strip is cut into the individual tips while the plate remains attached to the strip. The plate is then separated into the individual shanks to form the separate styli, whereby the orientation of the crystallographic plane with respect to the shank is uniform for all styli.

Abstract: A system for measuring shoe length of a stylus adapted to track a path along a surface of a video disc comprises positioning the tip of the stylus adjacent the surface of a substrate having a signal therein for effecting capacitive variations between the stylus and the substrate, and measuring the capacitive variations between the stylus and the substrate while they are oriented in a first position to obtain a first signal. The stylus is then tilted an angle of .theta. degrees relative to the substrate, whereby the stylus and substrate are oriented in a second position relative to each other. The capacitive variations are measured while the stylus and substrate are oriented in the second position to obtain a second signal. The first signal is then compared with the second signal to obtain a difference signal proportional to the shoe length of the stylus.

Abstract: A pickup stylus adapted for playing back prerecorded signals from a disc record groove of a given width upon establishment of stylus/record relative motion has a dielectric support element which has a tip. The terminating portion of the tip is shaped to have a prow, a substantially flat rear surface remote from the prow, a pair of substantially parallel side surfaces extending from the side edges of the rear surface, a bottom surface extending from the bottom edge of the rear surface and additional surfaces extending from the prow and intersecting the bottom and the side surfaces. The stylus tip is dimensioned such that the maximum separation between the substantially parallel side surfaces is less than the given width.

Abstract: A novel pickup stylus adapted for playing back prerecorded signals from a video disc has an arrowhead-shape cross-section in the region of its tip. The pickup stylus includes a dielectric support element which has a prow defining the apex of the arrowhead-shape cross-section and a substantially flat rear surface remote from the prow defining the base of the arrowhead-shape cross-section. The entire rear surface is covered with conductive material to form a narrowed-electrode in the region of its tip.

Abstract: A keel-tipped stylus comprises a tapering body, a fore-and-aft constricted terminal portion and shoulders joining the tapering body to the constricted terminal portion. To form a keel-tipped stylus, a tapering support element, made from hard material--such as diamond or sapphire-- is run on an abrasive lapping disc having a deep coarse-pitched groove. The lands on the lapping disc lap the shoulders of the keel-tipped stylus and the walls of the abrasive groove form the substantially parallel fore-and-aft surfaces of the constricted terminal portion. The abrasive groove can be deeper than the height of the keel tip; in that case, the bottom surface of the constricted terminal portion can be lapped later. Alternately, the bottom of the abrasive groove can be positioned such that it laps the bottom surface of the constricted terminal portion during the concluding portion of the keel-lapping procedure.