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. 18, 1981
Filed:
May. 21, 1979
George J Kren, Los Altos, CA (US);
Franklin R Koenig, Palo Alto, CA (US);
Tencor Instruments, Mountain View, CA (US);
Abstract
A gauge for measuring variations in distance of a surface relative to a reference by means of phase shifts in a zone of high acoustic impedance. A gauge head is provided with a first orifice for emitting acoustic waves, driven by a reference signal, toward a surface positioned very close to the gauge head, forming a high impedance zone. A second orifice in the gauge head picks up acoustic waves subjected to the zone and these waves are converted to electrical signals for comparison to the reference signal in a phase detector. The phase error between the two signals is indicative of surface distance variations.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile