An electronic device is provided with a display such as a liquid crystal display mounted in an electronic device housing. The display has a layer of liquid crystal material sandwiched between an upper display layer such as a color filter layer and a lower display layer such as a thin-film-transistor layer. An upper polarizer is formed on the upper surface of the color filter layer. A lower polarizer is formed on the lower surface of the thin-film-transistor layer. To protect display layers such as a glass color filter layer substrate for the color filter layer from damage during polarizer trimming operations, a coating is deposited on a peripheral edge of the glass color filter layer substrate. The coating may be formed from an elastomeric polymer such as silicone and may remain in place or may be removed following trimming operations.