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:
May. 10, 1988
Filed:
Oct. 26, 1984
Joseph S Eckerle, Redwood City, CA (US);
Mitutoyo Mfg. Co., Ltd., Tokyo, JP;
Abstract
In a capacitance type displacement measuring instrument, wherein a change in electric capacitance between electrodes due to a relative displacement between two members movable relative to each other is detected on the basis of a change in phase of a detection signal, and a relative displacement between the two members is measured from the change in phase, square waveform signals are applied in inversed phase to two transmitting electrodes provided on one of the members and signals induced on two wave pattern electrodes provided on the other of the members are received by receiving electrodes provided on the first of the members. Outputs from the receiving electrodes are successively taken in by a multiplexer, and then the amplitude-modulated square wave signals, outputted from the multiplexer, are demodulated. A phase detector measures the phase of the demodulated waveform, thereby measuring the relative displacement on the basis of change in phase.