A privacy screen for a display that comprises a polarizing film and a birefringent film is described. The method also includes measuring a length of time between receiving a handover command and returning to the base station. Herein the resource blocks of the interfering cell, which are co-located with the resource blocks according to the negotiation, may be allocated to another UE by the interfering cell without being divided. Second selection lines are electrically connected to selection terminals of second unit substrates disposed in even-number layers, pass through some of the unit substrates, and extend to the lowermost substrate of the unit substrates.