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:
Aug. 13, 1985
Filed:
Jun. 29, 1982
Akiyuki Yoshisato, Soma, JP;
Kohta Iijima, Soma, JP;
Alps Electric Co., Ltd., , JP;
Abstract
A capacitance detector for detecting a capacitance variation from a video disk and demodulating the capacitance variation into an electric signal, comprises a first block which includes a fixed oscillator, and a coupling loop comprised of a coupling coil and a coupling capacitor, the inductance of the fixed oscillator being inductively coupled with the coupling loop; and a second block which includes a disk stylus resonator having its resonance frequency varied by the capacitance variation of the video disk. A shield plate separates the first block from the second block and a coupling window is provided which inductively couples the coupling loop with the resonant inductance of the disk stylus resonator.