Method and apparatus for thickness determination in multilayer articles
US5974886A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1997 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Sep 15, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/044
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An exemplary apparatus for determining the thicknesses of individual layers in a multilayer article comprises an ultrasonic transducer coupled to the multilayer article with a buffer rod of similar acoustic properties, a pulser-receiver-amplifier which generates ultrasonic waves to produce discernible, time resolved pulse echoes, a digitizing oscilloscope which may be used to view the received pulse echoes, and a computer for controlling data acquisition and analysis. The computer is programmed to execute the exemplary method, which comprises the steps of selecting a center frequency of a transducer such that respective pulse echoes produced at the interfaces between layers of the multilayer article each have a common distinguishing feature with a signal to noise ratio greater than or equal to a predetermined value, and the pulse echoes are resolved in time; determining a transit time correction factor for the layer of the multilayer article based on an actual transit time measured with the transducer adjacent to the layer and an apparent transit time measured with the transducer not adjacent to the layer; propagating a pulse through the multilayer article to produce pulse echoes a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.