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Proceedings Paper

Van der Lugt optical correlation for the measurement of leak rates of hermetically sealed packages
Author(s): Colleen Mary Fitzpatrick; Edward P. Mueller
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Paper Abstract

Van der Lugt optical correlation, involving Fourier transform holography, has been shown to be successful in detecting and accurately measuring leak rates in hermetically sealed packages in the range of 10' to iO6 atm cc/sec. The technique depends on the measurement of the relaxation time of sealed packages under vacuum conditions, from which leak rates can be calculated. This technique has the advantage over conventional 'leak testing, in that it requires no backfilling with tracer gas, and therefore is more cost effective and faster. Also, packages such as pacemakers can be examined at the end of the manufacturing process, after the polymer neck has been inserted, eliminating any absorption of the helium or radioactive tracer gas that normally reduces the accuracy of conventional methods. Furthermore, this new technique can be used to rapidly test packages with large internal free volumes, in that it requires only a small differential pressure across the walls of the package, and avoids measurements depending on slowly changing internal helium or tracer gas concentrations. A comparison will be made between this HNDT technique and other leak testing methods commonly used in the packaging industry, in terms of cost and time factors, and range of accuracy.

Paper Details

Date Published: 1 January 1991
PDF: 8 pages
Proc. SPIE 1332, Optical Testing and Metrology III: Recent Advances in Industrial Optical Inspection, (1 January 1991); doi: 10.1117/12.51068
Show Author Affiliations
Colleen Mary Fitzpatrick, Electro Optic Consulting Services (United States)
Edward P. Mueller, Ctr. for Devices and Radiological Health/FDA (United States)

Published in SPIE Proceedings Vol. 1332:
Optical Testing and Metrology III: Recent Advances in Industrial Optical Inspection
Chander Prakash Grover, Editor(s)

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