The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 1978
Filed:
Oct. 28, 1976
Akira Asano, Yokohama, JP;
Keiji Segawa, Yokohama, JP;
Abstract
A stylus for the capacitive pickup of information signals inscribed in a recording medium as a geometrical variation comprises a corundum single crystal rod having two parallel side faces, which are inherently flat and optically smooth, and a thin electrode film coated on one of these two side faces. The electrode film is normal to the c-axis of the crystal, and the longitudinal axis of the rod coincides with one of the a-axes. The rod is formed by the 'edge defined film fed growth' method, wherein corundum melt is made to spread as a film over a flat shape-defining surface and a seed crystal is pulled vertically through a capillary so that an elongated crystal is continuously grown. The c-axes of the grown and seed crystals are parallel to the shape-defining surface and normal to the growth direction. Thereby, the rod is formed without the need of machining and abrading steps, other than steps for the shaping of a tip.