Articolo in rivista, 2010, ENG, 10.1063/1.3361512

Measuring liquid crystal anchoring energy strength by spectroscopic ellipsometry

A. Marino 1; V. Tkachenko 1; E. Santamato 2; N. Bennis 3; X. Quintana 3; J.M. Oton 3; G. Abbate 1

1 CNR-SPIN and Dipartimento di Scienze Fisiche, University of Naples Federico II, Via Cintia, I-80126, Italy; 2 CNISM and Dipartimento di Scienze Fisiche, University of Naples Federico II, Via Cintia, I-80126, Italy; 3 Universidad Politécnica de Madrid, 28040 Madrid, Spain

We describe an experimental procedure for accurate measurement of anchoring energy strength of liquid crystal cells. This technique is based on the possibility of gathering a large amount of very precise data about the linear optical response of the cell in different experimental conditions, using spectroscopic ellipsometry. Then, a careful data analysis exploiting data inversion method, supplemented by simulations from the elastic theory, is able to provide the searched information. The technique has been applied to vertical aligned nematic cells, chosen for its widespread use in the present display market. The results obtained in this particular case together with a thorough comparison with existing alternative techniques, suggest that our technique can be an optimum candidate for the industrial implementation of such measurement. A particular example is fully worked out, giving a result with a precision of 1.5% and an accuracy of 10%.

Journal of applied physics 107 , pp. 073109-1–073109-7

Keywords

CNR authors

Abbate Giancarlo, Marino Antigone, Tkachenko Volodymyr

CNR institutes

SPIN – Istituto superconduttori, materiali innovativi e dispositivi