Display device, method for driving the same, and electronic device using the display device and the method
View Patent ↗An object is to reduce degradation of display quality due to variation in luminance of light-emitting elements, which is caused by variation in voltage because of wiring resistance of current supply lines, and to improve the display quality. In a voltage program period, a terminal serving as a source of a transistor for driving an EL element is electrically connected to a first wiring to which a first potential is supplied. In a light-emitting period, the terminal serving as the source of the driving transistor is electrically connected to a second wiring to which a second potential is supplied. Accordingly, voltage between a gate terminal and the source terminal of the driving transistor can be held without being adversely affected by wiring resistance of the current supply lines.
1. A display device comprising:
a first wiring;
a second wiring; and
a pixel, the pixel comprising:
a transistor;
a compensation circuit electrically connected to a first terminal, a second terminal, and a gate terminal of the transistor, and configured to hold a threshold voltage applied between the gate terminal and the first terminal of the transistor and a video voltage;
a first switch electrically connected to the first terminal of the transistor and the first wiring, and configured to control electrical conduction between the first wiring and the first terminal of the transistor;
a second switch electrically connected to the first terminal of the transistor and the second wiring, and configured to control electrical conduction between the second wiring and the first terminal of the transistor; and
a light-emitting element having:
a first terminal electrically connected to the first wiring through the compensation circuit, the transistor, and the first switch, and the second wiring through the compensation circuit, the transistor, and the second switch; and
a second terminal electrically connected to a third wiring.
2. The display device according to claim 1 , wherein a width of the first wiring is larger than a width of the second wiring.
3. The display device according to claim 1 , wherein a width of the first wiring and a width of the second wiring vary by color element of the light-emitting element.
4. The display device according to claim 1 , wherein the display device is applied to an electronic device.
5. The display device according to claim 4 , wherein the electronic device is selected from the group consisting of a personal computer, a digital camera, a video camera, a portable information terminal, a navigation system, an electronic game machine, and a player for reproducing a recording medium.
6. The display device according to claim 5 , wherein the portable information terminal is selected from the group consisting of a mobile computer, a mobile telephone, and an electronic book.
7. A display device comprising:
a first wiring;
a second wiring; and
a pixel, the pixel comprising:
a transistor;
a compensation circuit electrically connected to a first terminal, a second terminal, and a gate terminal of the transistor, and configured to hold a threshold voltage applied between the gate terminal and the first terminal of the transistor and a video voltage;
a first switch electrically connected to the first terminal of the transistor and the first wiring, and configured to control electrical conduction between the first wiring and the first terminal of the transistor;
a second switch electrically connected to the first terminal of the transistor and the second wiring, and configured to control electrical conduction between the second wiring and the first terminal of the transistor; and
a light-emitting element having:
a first terminal electrically connected to the first wiring through the compensation circuit, the transistor, and the first switch, and the second wiring through the compensation circuit, the transistor, and the second switch; and
a second terminal electrically connected to a third wiring,
wherein the third wiring is further electrically connected to the compensation circuit.
8. The display device according to claim 7 , wherein a width of the first wiring is larger than a width of the second wiring.
9. The display device according to claim 7 , wherein a width of the first wiring and a width of the second wiring vary by color element of the light-emitting element.
10. The display device according to claim 7 , wherein the display device is applied to an electronic device.
11. The display device according to claim 10 , wherein the electronic device is selected from the group consisting of a personal computer, a digital camera, a video camera, a portable information terminal, a navigation system, an electronic game machine, and a player for reproducing a recording medium.
12. The display device according to claim 11 , wherein the portable information terminal is selected from the group consisting of a mobile computer, a mobile telephone, and an electronic book.
13. A display device comprising:
a first wiring;
a second wiring;
a pixel, the pixel comprising:
a transistor;
a compensation circuit electrically connected to a first terminal, a second terminal, and a gate terminal of the transistor, and configured to hold a threshold voltage applied between the gate terminal and the first terminal of the transistor and a video voltage;
a first switch electrically connected to the first terminal of the transistor and the first wiring, and configured to control electrical conduction between the first wiring and the first terminal of the transistor;
a second switch electrically connected to the first terminal of the transistor and the second wiring, and configured to control electrical conduction between the second wiring and the first terminal of the transistor; and
a light-emitting element having:
a first terminal electrically connected to the first wiring through the compensation circuit, the transistor, and the first switch, and to the second wiring through the compensation circuit, the transistor, and the second switch; and
a second terminal electrically connected to a third wiring; and
a fourth wiring electrically connected to the compensation circuit.
14. The display device according to claim 13 , wherein a width of the first wiring is larger than a width of the second wiring.
15. The display device according to claim 13 , wherein a width of the first wiring and a width of the second wiring vary by color element of the light-emitting element.
16. The display device according to claim 13 , wherein the display device is applied to an electronic device.
17. The display device according to claim 16 , wherein the electronic device is selected from the group consisting of a personal computer, a digital camera, a video camera, a portable information terminal, a navigation system, an electronic game machine, and a player for reproducing a recording medium.
18. The display device according to claim 17 , wherein the portable information terminal is selected from the group consisting of a mobile computer, a mobile telephone, and an electronic book.
19. A method for driving a display device, the display device comprising:
a first wiring;
a second wiring; and
a pixel, the pixel comprising:
a transistor;
a compensation circuit electrically connected to a first terminal, a second terminal, and a gate terminal of the transistor, and configured to hold in a capacitor a threshold voltage applied between the gate terminal and the first terminal of the transistor and a video voltage applied from a signal line through a selection switch;
a first switch electrically connected to the first terminal of the transistor and the first wiring, and configured to control electrical conduction between the first wiring and the first terminal of the transistor;
a second switch electrically connected to the first terminal of the transistor and the second wiring, and configured to control electrical conduction between the second wiring and the first terminal of the transistor; and
a light-emitting element having:
a first terminal electrically connected to the first wiring through the compensation circuit, the transistor, and the first switch, and to the second wiring through the compensation circuit, the transistor, and the second switch; and
a second terminal electrically connected to a third wiring,
the method comprising the steps of:
in a voltage program period, turning on the first switch and turning off the second switch; and
in a light-emitting period, turning off the first switch and turning on the second switch, and making the light-emitting element emit light.
20. The method for driving a display device according to claim 19 , wherein a voltage applied between the gate terminal and the first terminal of the transistor is modified to compensate the mobility of the transistor.