Measurement of the thermomechanical strain of electronic devices by shearography

This paper deals with the optical measurement of strain in electronic power devices under normal operating conditions. This non-contact and non-invasi ve method called shearography is based upon speckle interferometry. The tec hnique developed produces images of normal displacement gradient of devices . Numerical processing allows the determination of the surface displacement and its related strain. The main advantages of the measuring tool are to b e a simple optical set-up, to be very robust with a good sensitivity and to measure directly strain. Therefore, his well suited to fit into an industr ial environment. (C) 2000 Elsevier Science Ltd. Ail rights reserved.