High resolution ultrasonic coating thickness gauge

US5723791A · kind A · utility

Assignee

• DeFelsko Corporation · US

Inventors

• Frank Koch · Osterode, DE
• Leon C. Vandervalk · Brockville, CA
• David Beamish · Mississauga, CA

Key dates

• Filing date: Sep 28, 1993
• Grant date: Mar 3, 1998
• Expiry date: Sep 28, 2013

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B17/025
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A gauge for determining a thickness of a coating on a substrate includes a transducer for emitting ultrasonic signals into the coating and for generating electrical signals proportional to the ultrasonic signals received by the transducer, the received signals include first signals reflected from a transducer/coating interface and second signals reflected from a coating/substrate interface; a pulser for sending pulses to the transducer to trigger the emission of the ultrasonic signals; a sampler for sampling the electrical transducer signals and generating sampled data; a timer for controlling the pulser and the sampler so as to perform an equivalent time sampling of the signals received by the sampler; and a controller for calculating a thickness of the coating based on the sampled data, the controller includes the ability to subject the sampled data to a deconvolution analysis so as to distinguish sampled data corresponding to the first signals from sampled data corresponding to the second signals when the coating is thinner than a wavelength of the ultrasonic signal emitted by the transducer.