Electro-optical responses in hybrid TN (HTN) cells constructed with different types of substrates were investigated. The substrate surfaces were coated with PI or PVA for parallel orientation, and silane coupling agents(AY43) for perpendicular orientation. The cells were filled with nematic liquid crystalline mixture including a chiral dopant to exhibit hybrid alignment with a twisted structure. The electro-optical responses depend upon the surface treatment for parallel orientation and the concentration of the chiral dopant.
