A novel optical method in micro drop deformation measurements

A novel method was developed to determine the deformation of a micro drop o n a substrate. The principle of the method is based on the scattering of pa rallel fringes pattern from the deformed droplet, Because only a very few c omponents are needed together with a conventional laser Doppler anemometry (LDA) transmitting unit, the newly developed method is very easy to be impl emented. Within the geometrical optics approach, it is possible to reconstr uct the profile of a non-spherical micro drop from the scattered interferen ce fringes. The spatial frequency of the fringes was analyzed using fast Fo urier transform (FFT). The validation experiments for this method in the de termination of micro drop deformation which is affected by gravity, capilla ry Force and surface tension were performed and the results are agreed well with the theoretical analysis. (C) 2001 Elsevier Science Ltd. All rights r eserved.