Semiconductor display device and driving method the same
It is an object to provide a semiconductor display device having a touch panel, which can reduce power consumption. The semiconductor display device includes a panel which is provided with a pixel portion and a driver circuit which controls an input of the image signal to the pixel portion, and a touch panel provided in a position overlapping with the panel in the pixel portion. The pixel portion includes a display element configured to perform display in accordance with voltage of the image signal to be input, and a transistor configured to control retention of the voltage. The transistor includes an oxide semiconductor in a channel formation region. The driving frequency of the driver circuit, that is, the number of writing operations of the image signal for a certain period is changed in accordance with an operation signal from a touch panel.
1. A display device comprising:
a pixel portion comprising a pixel;
a driver circuit configured to drive the pixel portion; and
a touch panel overlapping with the pixel portion,
wherein an image signal is written to the pixel in a first period,
wherein supply of a power supply potential and a driving signal to the driver circuit is stopped in a second period, and
wherein the second period is terminated by an operation signal supplied from the touch panel.
2. The display device according to claim 1 , wherein a driving frequency of the driver circuit is changed in accordance with the operation signal supplied from the touch panel.
3. The display device according to claim 1 , wherein a length of displaying a still image in the pixel portion is changed in accordance with the operation signal supplied from the touch panel.
4. The display device according to claim 1 , wherein a driving frequency of the driver circuit when a still image is displayed in the pixel portion is lower than the driving frequency of the driver circuit when a moving image is displayed in the pixel portion.
5. The display device according to claim 1 , wherein the touch panel uses any one of a resistive system, a touch panel capacitance system, an ultrasonic system, an optics system, and an electromagnetic induction system.
6. The display device according to claim 1 , wherein the touch panel comprises a plurality of first electrodes and a plurality of second electrodes.
7. A display device comprising:
a pixel portion comprising a pixel;
a driver circuit configured to drive the pixel portion; and
a touch panel overlapping with the pixel portion,
wherein an image signal is written to the pixel in a first period,
wherein supply of a power supply potential and a driving signal to the driver circuit is stopped in a second period,
wherein the second period is terminated by an operation signal supplied from the touch panel, and
wherein the pixel comprises a transistor comprising an oxide semiconductor.
8. The display device according to claim 7 , wherein a driving frequency of the driver circuit is changed in accordance with the operation signal supplied from the touch panel.
9. The display device according to claim 7 , wherein a length of displaying a still image in the pixel portion is changed in accordance with the operation signal supplied from the touch panel.
10. The display device according to claim 7 , wherein a driving frequency of the driver circuit when a still image is displayed in the pixel portion is lower than the driving frequency of the driver circuit when a moving image is displayed in the pixel portion.
11. The display device according to claim 7 , wherein the touch panel uses any one of a resistive system, a touch panel capacitance system, an ultrasonic system, an optics system, and an electromagnetic induction system.
12. The display device according to claim 7 , wherein the touch panel comprises a plurality of first electrodes and a plurality of second electrodes.
13. The display device according to claim 7 , wherein an off-state current density of the transistor is less than or equal to 100 zA/μm.
14. The display device according to claim 1 , wherein the driving signal comprises a start signal and a clock signal.
15. The display device according to claim 1 , wherein, in the second period, a still image is displayed in the pixel portion.
16. The display device according to claim 7 , wherein the driving signal comprises a start signal and a clock signal.
17. The display device according to claim 7 , wherein, in the second period, a still image is displayed in the pixel portion.
18. A display device comprising:
a pixel portion comprising a pixel;
a driver circuit configured to drive the pixel portion; and
a touch panel overlapping with the pixel portion,
wherein an image signal is written to the pixel in a first period,
wherein supply of a power supply potential and a driving signal to the driver circuit is stopped in a second period,
wherein the second period is terminated by an operation signal supplied from the touch panel,
wherein the pixel comprises a transistor, the transistor comprising:
a gate electrode;
a gate insulating film over the gate electrode;
an oxide semiconductor film over the gate insulating film;
a source electrode over the oxide semiconductor film;
a drain electrode over the oxide semiconductor film;
a silicon oxide film over the oxide semiconductor film, the source electrode, and the drain electrode; and
a silicon nitride film over the silicon oxide film,
wherein the transistor comprises a channel formation region in the oxide semiconductor film, and
wherein the oxide semiconductor film comprises indium, gallium, and zinc.
19. The display device according to claim 18 , wherein a driving frequency of the driver circuit is changed in accordance with the operation signal supplied from the touch panel.
20. The display device according to claim 18 , wherein a length of displaying a still image in the pixel portion is changed in accordance with the operation signal supplied from the touch panel.
21. The display device according to claim 18 , wherein a driving frequency of the driver circuit when a still image is displayed in the pixel portion is lower than the driving frequency of the driver circuit when a moving image is displayed in the pixel portion.
22. The display device according to claim 18 , wherein the driving signal comprises a start signal and a clock signal.
23. The display device according to claim 18 , wherein, in the second period, a still image is displayed in the pixel portion.