Note that as a method for providing a metal auxiliary wiring for a transparent electrode of an electro-optical element, a method by which the metal auxiliary wiring is provided so as to overlap with an upper surface of the transparent electrode or a lower surface of the transparent electrode and to be electrically connected to the transparent electrode has been known (for example, see Patent Document 1).
A structure in which an additional capacitor electrode provided for an active matrix substrate is formed of a conductive film having a light transmitting property of ITO, SnO2, or the like and an auxiliary wiring formed of a metal film is provided in contact with the additional capacitor electrode in order to reduce the electric resistance of the additional capacitor electrode has been known (see Patent Document 2).
Note that it has been known that, as each of a gate electrode, a source electrode, and a drain electrode of a field effect transistor formed using an amorphous oxide semiconductor film, a transparent electrode of indium tin oxide (ITO), indium zinc oxide, ZnO, SnO2, or the like, a metal electrode of Al, Ag, Cr, Ni, Mo, Au, Ti, Ta, or the like, or a metal electrode of an alloy containing any of the above elements can be used; and, by stacking two or more of these layers, contact resistance may be reduced or interface intensity may be improved (for example, see Patent Document 3).
Note that it has been known that, as a material of each of a source electrode, a drain electrode, a gate electrode and an auxiliary capacitor electrode of a transistor formed using an amorphous oxide semiconductor, a metal such as indium (In), aluminum (Al), gold (Au), or silver (Ag), or an oxide material such as indium oxide (In2O3), tin oxide (SnO2), zinc oxide (ZnO), cadmium oxide (CdO), cadmium indium oxide (CdIn2O4), cadmium tin oxide (Cd2SnO4), or zinc tin oxide (Zn2SnO4) can be used; and the same material or different materials may be used for the gate electrode, the source electrode, and the drain electrode (for example, see Patent Documents 4 and 5).