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:
Apr. 04, 1989
Filed:
Dec. 08, 1987
Leybold Aktiengesellschaft, Hanau, DE;
Abstract
The invention relates to a system for determining the current thickness of changing coatings of a material on a substrate, using an electrically excitable, mechanically vibratable element (2) having at least one pronounced resonant frequency, which is excited to a steady vibration by an oscillator circuit (1) at a resonant frequency, and which is covered by the material in the same manner as the substrate. A signal (U.sub.D) is produced which depends on the damping caused by the coating of the vibratable element (2). This signal (U.sub.D) is compared with a known critical value signal (U.sub.DE) whereby it is possible to indicate when the vibratable element (2), which can be coated with the material only to a certain degree, must be replaced with a new vibratable element (FIG. 2).