Patent attributes
An object is to suppress luminance variation due to change in the amount of current flowing through a light-emitting element, caused by change in environmental temperature. A monitor circuit for compensating the cathode potential of the light-emitting element in accordance with environmental temperature is provided in the vicinity of a pixel portion in order to compensate a change in properties, due to environmental temperature, of a transistor including an oxide semiconductor layer and the light-emitting element. The monitor circuit includes a monitor power supply line, a monitor transistor including an oxide semiconductor layer, a monitor light-emitting element, a current source circuit, and an amplification circuit that compensates the cathode potential of the light-emitting element. The potential of the monitor power supply line is lower than the potential of a power supply line in the pixel.
