US 4,033,592 AGranted

Record disc cutting stylus

AssigneeVictor Company of Japan, Ltd.

InventorsKaoru Totuka, Isao Ohwaki, Masahiro Ohba, Shinji Nakamura

Life of this patent

Estimating the term…

Loading patent…

Abstract

A record disc cutting stylus comprises a cutting stylus body which is held at its upper end by a shank. At its lower end, there is a stylus tip portion which has a mirror surface, a relief surface with a relief angle .gamma., and a burnishing facet with a burnishing angle .beta. and a burnishing facet width d. The burnishing angle .beta. is as large as possible, and the width d and the relief angle .gamma. are as small as possible. The stylus projects distance l between the lower end face of the shank and the extreme tip of the stylus tip portion, which projection is as small as possible. The burnishing angle .beta. has a value substantially within a range of 25.degree. to 40.degree.; the burnishing facet width d is substantially within a range of 0.5 .mu.m to 3.0 .mu.m; the relief angle .gamma. is substantially within a range of 30.degree. to 40.degree.; and the stylus projecting distance l is substantially less than 2.0 .mu.m.

Claims1

Dependent claims

A cutting stylus for recording multiplexed signals on a record disc, said signals comprising a direct wave signal and an angle modulated signal, said stylus comprising a cutting stylus body having a stylus tip portion for cutting a groove on the record disc and a shank holding the upper part of the stylus body, said stylus tip portion having a mirror surface at the front part thereof which faces in the direction in which cutting advances relative to the record disc, a burnishing angle in the range of approximately 25.degree. to 40.degree., a relief surface in the range of approximately 30.degree. to 40.degree. at the rear part of said tip portion, and a burnishing facet having a width in the range approximately 0.5 .mu.m to 3.0 .mu.m between the mirror surface and the relief surface, the distance l from the lower end face of the shank to the extreme tip end of the stylus tip being within a range from approximately 2.0 mm to a lower limit which is determined by factors of fabrication, the stylus operating at a maximum signal level which decreases with a slope of -6dB/octave with increasing frequency.

Dependencies are inferred from the claim text.