Display device having pixel including transistor and driving method of the same
View Patent ↗A first capacitor obtains a gate-source voltage of a first transistor in accordance with a programming current flowing through the first transistor, and a second capacitor obtains a threshold voltage of a second transistor. Then, the electric charges held in the first capacitor and the second capacitor are capacitively coupled. By using the voltage obtained with the capacitively coupling as a gate-source voltage of the first transistor, constant current in accordance with the programming current can be supplied to a light emitting element.
1. A display device comprising:
a pixel comprising:
a first switching element;
a second switching element;
a third switching element;
a fourth switching element;
a fifth switching element;
a first transistor comprising a first terminal connected to a first wire, a second terminal connected to a second wire through the first switching element, and to a gate of the first transistor through the second switching element;
a second transistor comprising a first terminal connected to the first wire and a second terminal connected to a gate of the second transistor through the third switching element;
a first capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the first transistor and to a first terminal of the fourth switching element;
a second capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the second transistor and to a second terminal of the fourth switching element; and
a light emitting element comprising one electrode connected to the second terminal of the first transistor through the fifth switching element.
2. The display device according to claim 1 ,
wherein the first transistor and the second transistor have a same conductive type.
3. The display device according to claim 1 ,
wherein a channel length of the first transistor is longer than a channel length of the second transistor.
4. The display device according to claim 1 ,
wherein a channel width of the first transistor is wider than a channel width of the second transistor.
5. The display device according to claim 1 ,
wherein the first transistor is connected in series to the light emitting element and controls a current flowing through the first transistor to control luminance of the light emitting element.
6. A display device comprising:
a pixel comprising:
a first switching element;
a second switching element;
a third switching element;
a fourth switching element;
a fifth switching element;
a first transistor comprising a first terminal connected to a first wire and a second terminal connected to a gate of the first transistor through the first switching element;
a second transistor comprising a first terminal connected to the first wire, a second terminal connected to a second wire through the second switching element and to a gate of the second transistor through the third switching element;
a first capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the first transistor and to a first terminal of the fourth switching element;
a second capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the second transistor and to a second terminal of the fourth switching element; and
a light emitting element comprising one electrode connected to the second terminal of the first transistor through the fifth switching element.
7. The display device according to claim 6 ,
wherein the first transistor and the second transistor have a same conductive type.
8. The display device according to claim 6 ,
wherein a channel length of the first transistor is longer than a channel length of the second transistor.
9. The display device according to claim 6 ,
wherein a channel width of the first transistor is wider than a channel width of the second transistor.
10. The display device according to claim 6 ,
wherein the first transistor is connected in series to the light emitting element and controls a current flowing through the first transistor to control luminance of the light emitting element.
11. A driving method of a display device comprising:
a pixel comprising:
a first transistor;
a second transistor;
a first capacitor which holds a gate-source voltage of the first transistor in accordance with a current flowing through the first transistor;
a second capacitor which holds a threshold voltage of the second transistor; and
a switching element comprising a first terminal directly connected to a gate of the first transistor and a second terminal directly connected to a gate of the second transistor,
said method comprising:
obtaining a gate-source voltage of the first transistor in the first capacitor;
obtaining a gate-source voltage of the second transistor in the second capacitor; and
turning on the switching element to capacitively couple the first capacitor and the second capacitor.
12. A driving method of a display device according to claim 11 ,
wherein an operation of obtaining the gate-source voltage of the first transistor in the first capacitor and an operation of obtaining the gate-source voltage of the second transistor in the second capacitor are performed at the same time.
13. A driving method of a display device comprising:
a pixel comprising:
a first switching element;
a second switching element;
a third switching element;
a fourth switching element;
a fifth switching element;
a first transistor comprising a first terminal connected to a first wire and a second terminal connected to a second wire through the first switching element and to a gate of the first transistor through the second switching element;
a second transistor comprising a first terminal connected to the first wire and a second terminal connected to a gate of the second transistor through the third switching element;
a first capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the first transistor and to a first terminal of the fourth switching element;
a second capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the second transistor and to a second terminal of the fourth switching element; and
a light emitting element comprising one electrode connected to the second terminal of the first transistor through the fifth switching element,
said method comprising:
obtaining a gate-source voltage of the first transistor in the first capacitor;
obtaining a gate-source voltage of the second transistor in the second capacitor; and
turning on the fourth switching element to capacitively couple the first capacitor and the second capacitor.
14. A driving method of a display device according to claim 13 ,
wherein an operation of obtaining the gate-source voltage of the first transistor in the first capacitor and an operation of obtaining the gate-source voltage of the second transistor in the second capacitor are performed at the same time.
15. A driving method of a display device comprising:
a pixel comprising:
a first switching element;
a second switching element;
a third switching element;
a fourth switching element;
a fifth switching element;
a first transistor comprising a first terminal connected to a first wire and a second terminal connected to a gate of the first transistor through the first switching element;
a second transistor comprising a first terminal connected to the first wire and a second terminal connected to a second wire through the second switching element and to a gate of the second transistor through the third switching element;
a first capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the first transistor and to a first terminal of the fourth switching element;
a second capacitor comprising one electrode connected to the first wire and the other electrode directly connected to the gate of the second transistor and to a second terminal of the fourth switching element; and
a light emitting element comprising one electrode connected to the second terminal of the first transistor through the fifth switching element,
said method comprising:
obtaining a gate-source voltage of the first transistor in the first capacitor;
obtaining a gate-source voltage of the second transistor in the second capacitor; and
turning on the fourth switching element to capacitively couple the first capacitor and the second capacitor.
16. A driving method of a display device according to claim 15 ,
wherein an operation of obtaining the gate-source voltage of the first transistor in the first capacitor and an operation of obtaining the gate-source voltage of the second transistor in the second capacitor are performed at the same time.