Influences of the surface elastic energy term K₁₃ on the critical fields of liquid crystal cells and experimental measurement of K₁₃

Based on the modified formula of Rapini—Papoular, the equation and boundary condition of the director of weak anchoring nematic liquid crystal (NLC) cell have been obtained in the case of existence of the surface elastic energy term K₁₃. The influences of K₁₃ on the threshold field and the saturation field have been studied in detail with the methods of analytical derivation and numerical calculation. A new method of checking whether K₁₃ exists or not is given in theory. Combining with the previous work, we also propose an experimental plan to measure the value of K₁₃ with a wedge-shaped planar-aligned weak anchoring NLC cell. The numerical experiments are carried out to verify the feasibility of our method.