Dielectric and pseudo-dielectric heating effects in a dual-frequency liquid crystal cell

Abstract

The dielectric heating (DH) effect is a common phenomenon observed in dual-frequency liquid crystal (DFLC) cells. The heating is caused by dielectric loss resulting from the hindered reorientation about the short molecular axes of the permanent dipoles under an alternating-current (AC) electrical stimulus. Recently, we have confirmed that pseudo-dielectric heating (PDH), in association with the pseudo-dielectric relaxation, occurs readily in a sandwiched LC cell with indium–tin-oxide (ITO) electrodes. This very heating effect, primarily originating from the nonnegligible resistivity of the electrode material, has long been misinterpreted as DH governed by the intrinsic dielectric property of the LC in an AC electric field. Since previous studies have suggested the presence of only DH in DFLC cells, the clarification and differentiation of PDH are highly desired. Providing compelling evidence for the independent existence of both the intrinsic DH and less-known PDH effects, this letter represents a pioneering study to demonstrate that the two heating effects exhibiting dissimilar behaviors can be unambiguously distinguished in a sandwich-type DFLC cell.