Order Reconstruction In Inverse Twisted Nematic Cell With An Applied Electric Field

The order reconstruction in an inverse twisted nematic(ITN)liquid crystal cell with an applied electric field is investigated based on the Landau–de Gennes theory and the two-dimensional finite-difference iterative method.Main contents are the following four parts:The first part,we study the eigenvalue exchange solutions and twisted solutions about the one dimension model in the absence of any defect and with the increase applied electric field.The Q value(Q value is stands for eigenvalue)in the study of the twisted solution patterns,it observes the change from positive order parameters uniaxial state to negative order parameters uniaxial state.Near the threshold voltage in 20? cell(? is the coherence length for order-parameter changes),the system is always a positive order parameter uniaxial state,but in the 10? cell,there is a negative order parameter uniaxial twisted state.Moreover,two critical cell gaps dc**= 7? and dc* = 12? exist in the study of the ITN cell.When d ? dc**(d is the reduced cell gap),only the eigenvalue change state exists.When d ? dc*,only a positive order parameter uniaxial twisted state exists near the threshold electric field.When dc** < d < dc*,a negative order parameter uniaxial twisted state exists near the threshold electric field.Due to the induced electric field effect,we get the twice eigenvalue exchange and thrice eigenvalue exchange images.In the second part,new Q graphics are combined with the traditional graphics.We mainly explain the emergence of new Q graphics,including twice and thrice eigenvalue exchange,negative order parameters uniaxial state and related parameters of biaxial state change process.In the third part,We study the twisted and eigenvalue exchange solutions in the 20? cell two-dimensional defective model,which is with a increase applied electric field.We can observe defect,defect move,diffusion process and disappear.Due to the electric field,the defect structure is diffusion.With a increase applied electric field,defect finally disappeared.The twice eigenvalue exchange and thrice eigenvalue exchange also come out.The fourth part,we summarize the research results and their regularity.And we discuss the unresolved issues.