Light emitting device

A light emitting device comprising:

• a first pixel portion, a second pixel portion, and an amplifier,
• said first pixel portion including:
• a first pixel, and
• a monitoring line,
• said first pixel comprising:
• a first light emitting element,
• a constant current source,
• a switch, and
• a circuit;
• and
• said second pixel portion including:
• a power supply line, and
• a second pixel,
• said second pixel comprising:
• a second light emitting element, and
• a transistor;
• wherein one electrode of the first light emitting element is connected to the monitoring line through the switch;
• wherein the circuit controls on and off of the switch in accordance with a potential of one electrode of the first light emitting element;
• wherein one electrode of the second light emitting element is connected to the power supply line through the transistor;
• wherein the monitoring line is connected to the power supply line through the amplifier;
• and
• wherein the constant current source supplies current to the first light emitting element.

A light emitting device comprising:

• a first pixel portion, a second pixel portion, and an amplifier,
• said first pixel portion including:
• a first pixel, and
• a monitoring line,
• said first pixel comprising:
• a first light emitting element,
• a constant current source,
• a first transistor, and
• an inverter;
• said second pixel portion including:
• a power supply line, and
• a second pixel,
• said second pixel comprising:
• a second light emitting element, and
• a second transistor;
• wherein one electrode of the first light emitting element is connected to the monitoring line through the first transistor;
• wherein the constant current source supplies current to the first light emitting element;
• wherein an input terminal of the inverter is connected to one electrode of the first light emitting element;
• wherein an output terminal of the inverter is connected to a gate electrode of the first transistor;
• wherein the inverter outputs a potential which controls on and off of the first transistor to the gate electrode of the first transistor in accordance with a potential of one electrode of the first light emitting element;
• wherein one electrode of the second light emitting element is connected to the power supply line through the second transistor;
• and
• wherein the monitoring line is connected to the power supply line through the amplifier.

A light emitting device comprising:

• a monitoring pixel comprising a first light emitting element, a constant current source, a switch, and a circuit;
• a pixel comprising a second light emitting element;
• a monitoring line;
• and
• an amplifier,
• wherein one electrode of the first light emitting element is connected to the amplifier through the switch and the monitoring line,
• wherein one electrode of the second light emitting element is connected to the amplifier through the monitoring line,
• wherein the circuit controls on and off of the switch in accordance with a potential of one electrode of the first light emitting element, and
• wherein the constant current source supplies current to the first light emitting element.