An electronic device display may have a color filter layer, a thin-film-transistor layer, and a layer of liquid crystal material. The display may have a display cover layer such as a layer of glass or plastic. Adhesive may be used to attach the upper polarizer to the display cover layer. The thin-film transistor layer may have a substrate with upper and lower surfaces. Thin-film-transistor circuitry may be formed on the upper surface. A display driver integrated circuit may be mounted to the lower surface or a flexible printed circuit and may be coupled to the thin-film-transistor circuitry using wire bonding wires. Through vias that are formed through the thin-film-transistor layer substrate may be used in coupling the thin-film-transistor circuitry to the display driver integrated circuit.