Element substrate and light-emitting device
A potential of a gate of a driving transistor is fixed, and the driving transistor is operated in a saturation region, so that a current is supplied thereto anytime. A current control transistor operating in a linear region is disposed serially with the driving transistor, and a video signal for transmitting a signal of emission or non-emission of the pixel is input to a gate of the current control transistor via a switching transistor.
1. A semiconductor device comprising:
a light-emitting element;
a first transistor;
a second transistor; and
a third transistor,
wherein one of a source and a drain of the first transistor is electrically connected to the light-emitting element,
wherein the other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the second transistor,
wherein a gate of the second transistor is electrically connected to one of a source and a drain of the third transistor,
wherein the other of the source and the drain of the third transistor is electrically connected to a first line,
wherein a gate of the first transistor is electrically connected to a second line,
wherein the other of the source and the drain of the second transistor is electrically connected to a third line,
wherein the third line comprises a conductive film,
wherein the conductive film overlaps with a channel formation region of the first transistor,
wherein the conductive film overlaps with a channel formation region of the second transistor,
wherein a semiconductor film comprises the channel formation region of the first transistor and the channel formation region of the second transistor, and
wherein a channel length of the first transistor is longer than a channel width of the first transistor.
2. The semiconductor device according to claim 1 , wherein the first transistor comprises silicon.
3. The semiconductor device according to claim 1 ,
wherein the light-emitting element, the first transistor, the second transistor and the third transistor are comprised in a first pixel, and
wherein the first line is electrically connected to a second pixel.
4. The semiconductor device according to claim 1 , wherein the semiconductor film has a winding shape.
5. The semiconductor device according to claim 4 , wherein the first transistor is a P-type transistor.
6. The semiconductor device according to claim 1 , wherein the second transistor is configured to operate in a linear area.
7. The semiconductor device according to claim 1 ,
wherein the light-emitting element comprises a first electrode, a light-emitting layer over the first electrode and a second electrode over the light-emitting layer,
wherein the light-emitting element is configured to pass light through the second electrode.
8. The semiconductor device according to claim 1 , wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
9. The semiconductor device according to claim 1 , wherein the first transistor is formed by using an SOI.
10. The semiconductor device according to claim 1 , further comprising a color filter over the light-emitting element.
11. A semiconductor device comprising:
a light-emitting element;
a first transistor;
a second transistor; and
a third transistor,
wherein one of a source and a drain of the first transistor is electrically connected to the light-emitting element,
wherein the other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the second transistor,
wherein a gate of the second transistor is electrically connected to one of a source and a drain of the third transistor,
wherein the other of the source and the drain of the third transistor is electrically connected to a first line,
wherein a gate of the first transistor is electrically connected to a second line,
wherein the other of the source and the drain of the second transistor is electrically connected to a third line,
wherein the second line comprises a first conductive film,
wherein the third line comprises a second conductive film,
wherein the second conductive film overlaps with a channel formation region of the first transistor,
wherein the second conductive film overlaps with a channel formation region of the second transistor,
wherein the second conductive film overlaps with the first conductive film,
wherein a semiconductor film comprises the channel formation region of the first transistor and the channel formation region of the second transistor, and
wherein a channel length of the first transistor is longer than a channel width of the first transistor.
12. The semiconductor device according to claim 11 , wherein the first transistor comprises silicon.
13. The semiconductor device according to claim 11 ,
wherein the light-emitting element, the first transistor, the second transistor and the third transistor are comprised in a first pixel, and
wherein the first line is electrically connected to a second pixel.
14. The semiconductor device according to claim 11 , wherein the semiconductor film has a winding shape.
15. The semiconductor device according to claim 14 , wherein the first transistor is a P-type transistor.
16. The semiconductor device according to claim 11 , wherein the second transistor is configured to operate in a linear area.
17. The semiconductor device according to claim 11 ,
wherein the light-emitting element comprises a first electrode, a light-emitting layer over the first electrode and a second electrode over the light-emitting layer,
wherein the light-emitting element is configured to pass light through the second electrode.
18. The semiconductor device according to claim 11 , wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
19. The semiconductor device according to claim 11 , wherein the first transistor is formed by using an SOI.
20. The semiconductor device according to claim 11 , further comprising a color filter over the light-emitting element.