Ion trapping films TOP-COAT TA606B20 are installed beneath the polyimide alignment films, which are coated over the ITO electrode films, in a polymer-stabilized ferroelectric liquid crystal display exhibiting V-shaped switching. The ion trapping films are shown to play the following two roles: one is to remove zigzag-defects owing to their planarizing function and the other is to remove mobile ions. The latter effect gives rise to the reduction of the operational voltage and an increase of the voltage holding ratio owing to the removal of the depolarization field.