Light emitting device and driving method of the same

A driving method of a light emitting device comprising a first transistor, a second transistor, a third transistor and a light emitting element,

• wherein the light emitting element comprises a pixel electrode, a counter electrode, and an electroluminescent layer formed between the pixel electrode and the counter electrode,
• wherein the second transistor and the third transistor are electrically connected in series between a first power supply line and the pixel electrode,
• wherein a gate electrode of the third transistor is electrically connected to one of a source electrode and a drain electrode of the first transistor, and
• wherein a gate electrode of the second transistor is electrically connected to a second power supply line, the driving method comprising:
• applying a first potential to the gate electrode of the third transistor by turning ON the first transistor;
• applying a third potential of the first power supply line to the counter electrode while the first potential is applied to the gate electrode of the third transistor;
• turning OFF the first transistor;
• and
• applying a fourth potential to the counter electrode so that a current flows in the light emitting element,
• wherein the first transistor operates in a linear region,
• wherein the second transistor operates in a saturation region,
• wherein the third transistor operates in a linear region,
• wherein a second potential of the second power supply line is fixed,
• wherein an amount of the current is controlled by the second transistor, and
• wherein the current does not flow in the light emitting element while the first transistor and the second transistor are ON.

A driving method of a light emitting device comprising a pixel comprising a first transistor, a second transistor, a third transistor and a light emitting element,

• wherein the light emitting element comprises a pixel electrode, a counter electrode, and an electroluminescent layer formed between the pixel electrode and the counter electrode,
• wherein the second transistor and the third transistor are electrically connected in series between a first power supply line and the pixel electrode,
• wherein a gate electrode of the first transistor is electrically connected to a scan line,
• wherein a gate electrode of the second transistor is electrically connected to a second power supply line having a second potential,
• wherein a gate electrode of the third transistor is electrically connected to one of a source electrode and a drain electrode of the first transistor, and
• wherein the scan line crosses the second power supply line,
• the driving method comprising:
• applying a first potential to the gate electrode of the third transistor by turning ON the first transistor by selecting the scan line, wherein the second transistor is ON when the first transistor is ON;
• making the counter electrode into a floating state while the first potential is applied to the gate electrode of the third transistor;
• turning OFF the first transistor;
• and
• applying a third potential to the counter electrode so that a current flows in the light emitting element,
• wherein the first transistor operates in a linear region,
• wherein the second transistor operates in a saturation region,
• wherein the third transistor operates in a linear region,
• wherein the second potential is a fixed potential,
• wherein an amount of the current is controlled by the second transistor, and
• wherein the current does not flow in the light emitting element while the first transistor and the second transistor are ON.

A driving method of a light emitting device comprising a pixel comprising a first transistor, a second transistor, a third transistor, and a light emitting element,

• wherein the light emitting element comprises a pixel electrode, a counter electrode, and an electroluminescent layer formed between the pixel electrode and the counter electrode,
• wherein the second transistor and the third transistor are electrically connected in series between a first power supply line and the pixel electrode,
• wherein a gate electrode of the first transistor is electrically connected to a scan line,
• wherein a gate electrode of the second transistor is electrically connected to a second power supply line, and
• wherein a gate electrode of the third transistor is electrically connected to one of a source electrode and a drain electrode of the first transistor,
• the driving method comprising:
• applying a first potential to the gate electrode of the third transistor by turning ON the first transistor by selecting the scan line, wherein the second transistor is ON while the first transistor is ON;
• making the counter electrode into a floating state while the first potential is applied to the gate electrode of the third transistor;
• turning OFF the first transistor;
• and
• applying a third potential to the counter electrode so that a current flows in the light emitting element,
• wherein the second power supply line is configured to be supplied with a second potential which is a fixed potential,
• wherein the current does not flow in the light emitting element while the first transistor and the second transistor are ON,
• wherein the first transistor operates in a linear region,
• wherein the second transistor operates in a saturation region, and
• wherein the third transistor operates in a linear region.