Light-emitting device
View Patent ↗To provide a light-emitting device in which variation in luminance among pixels caused by variation in threshold voltage of transistors can be suppressed. The light-emitting device includes a transistor including a first gate and a second gate overlapping with each other with a semiconductor film therebetween, a first capacitor maintaining a potential difference between one of a source and a drain of the transistor and the first gate, a second capacitor maintaining a potential difference between one of the source and the drain of the transistor and the second gate, a switch controlling conduction between the second gate of the transistor and a wiring, and a light-emitting element to which drain current of the transistor is supplied.
1. A light-emitting device comprising:
a first transistor comprising a first gate, a second gate and a semiconductor film between the first gate and the second gate;
a first capacitor configured to hold a potential difference between one of a source and a drain of the first transistor and the first gate of the first transistor;
a second capacitor configured to hold a potential difference between the one of the source and the drain of the first transistor and the second gate of the first transistor;
a first switch configured to control connection between the second gate of the first transistor and a wiring;
a second switch configured to control connection between the first gate of the first transistor and the one of the source and the drain of the first transistor; and
a light-emitting element to which drain current of the first transistor is supplied.
2. The light-emitting device according to claim 1 , wherein the first transistor is an n-channel transistor.
3. The light-emitting device according to claim 2 , wherein the first transistor includes a channel formation region in an oxide semiconductor film.
4. The light-emitting device according to claim 1 , wherein the first and second switches each includes a second transistor.
5. The light-emitting device according to claim 4 , wherein the second transistor is an n-channel transistor.
6. The light-emitting device according to claim 5 , wherein the second transistor includes a channel formation region in an oxide semiconductor film.
7. A light-emitting device comprising:
a first transistor comprising a first gate, a second gate and a semiconductor film between the first gate and the second gate;
a first capacitor, wherein a first electrode of the first capacitor is electrically connected to the first gate of the first transistor, and a second electrode of the first capacitor is electrically connected to one of a source and a drain of the first transistor;
a second capacitor, wherein a first electrode of the second capacitor is electrically connected to the second gate of the first transistor, and a second electrode of the second capacitor is electrically connected to the one of the source and the drain of the first transistor;
a first switch, wherein a first terminal of the first switch is electrically connected to the second gate of the first transistor, and a second terminal of the first switch is electrically connected to a wiring;
a second switch, wherein a first terminal of the second switch is electrically connected to the first gate of the first transistor, and a second terminal of the second switch is electrically connected to the one of the source and the drain of the first transistor; and
a light-emitting element electrically connected to the one of the source and the drain of the first transistor.
8. The light-emitting device according to claim 7 , wherein the first transistor is an n-channel transistor.
9. The light-emitting device according to claim 8 , wherein the first transistor includes a channel formation region in an oxide semiconductor film.
10. The light-emitting device according to claim 7 , wherein the first and second switches each includes a second transistor.
11. The light-emitting device according to claim 10 , wherein the second transistor is an n-channel transistor.
12. The light-emitting device according to claim 11 , wherein the second transistor includes a channel formation region in an oxide semiconductor film.
13. A light-emitting device comprising:
a first transistor comprising a first gate, a second gate and a semiconductor film between the first gate and the second gate;
a first capacitor, wherein a first electrode of the first capacitor is electrically connected to the first gate of the first transistor, and a second electrode of the first capacitor is electrically connected to one of a source and a drain of the first transistor;
a second capacitor, wherein a first electrode of the second capacitor is electrically connected to the second gate of the first transistor, and a second electrode of the second capacitor is electrically connected to the one of the source and the drain of the first transistor;
a light-emitting element electrically connected to the one of the source and the drain of the first transistor;
a first switch, wherein a first terminal of the first switch is electrically connected to the second gate of the first transistor, and a second terminal of the first switch is electrically connected to a wiring;
a second switch, wherein a first terminal of the second switch is electrically connected to the first gate of the first transistor, and a second terminal of the second switch is electrically connected to the light-emitting element;
a third switch electrically connected to the first gate of the first transistor; and
a fourth switch electrically connected to the light-emitting element.
14. The light-emitting device according to claim 13 , wherein the first transistor is an n-channel transistor.
15. The light-emitting device according to claim 14 , wherein the first transistor includes a channel formation region in an oxide semiconductor film.
16. The light-emitting device according to claim 13 , wherein the first to fourth switches each includes a second transistor.
17. The light-emitting device according to claim 16 , wherein the second transistor is an n-channel transistor.
18. The light-emitting device according to claim 17 , wherein the second transistor includes a channel formation region in an oxide semiconductor film.
19. The light-emitting device according to claim 13 , further comprising a fifth switch, wherein the one of the source and the drain of the first transistor and the light-emitting element are electrically connected to each other through the fifth switch.