Patent attributes
A first oxide semiconductor thin-fil transistor includes a top gate electrode, a first metal oxide film, and a top gate insulating film between the top gate electrode and the first metal oxide film. A second oxide semiconductor thin-film transistor includes a bottom gate electrode, a second metal oxide film, and a bottom gate insulating film between the bottom gate electrode and the second metal oxide film. A storage capacitor stores a signal voltage to the bottom gate electrode. A first electrode of the storage capacitor includes a part of the bottom gate electrode. A source/drain region of the first oxide semiconductor thin-film transistor is in contact with the bottom gate electrode in a contact hole in the bottom gate insulating layer. Capacitance per unit area of the bottom gate insulating film is smaller than capacitance per unit area of the top gate insulating film.