Display device and driving method

1. A display device comprising:

a display portion comprising a plurality of electrodes which are arranged two-dimensionally on a substrate;

a touch detection circuit which supplies a drive signal for touch detection to an electrode selected from among the plurality of electrodes, receives a signal from the selected electrode, and outputs a guard signal for reducing a parasitic capacitance to unselected electrodes; and

a scanning line drive circuit which supplies a scanning signal to a plurality of scanning lines extending in the display portion, wherein

a frame period, which comprises a display period in which the scanning signal is supplied to the plurality of scanning lines for image display, and a touch detection period related to sensing using the plurality of electrodes, includes a first frame and a second frame, and

the number of scanning lines to which the scanning signal is supplied in each display period included in the first and second frames is adjusted such that a potential of the touch detection period included in the first frame matches a potential of the touch detection period included in the second frame.

2. The display device of claim 1 , wherein the first and second frames each include a plurality of display periods and a plurality of touch detection periods, and the display period and the touch detection period occur alternately.

3. The display device of claim 1 , wherein the potential of each of the touch detection periods included in the first and second frames is equal to a potential of an immediately preceding display period.

4. The display device of claim 1 , wherein:

the number of scanning lines to which the scanning signal is supplied in each of the display periods included in the first and second frames is adjusted to be equal to a multiple of 8 uniformly; and

the scanning line drive circuit supplies the scanning signal to the scanning lines, the number of which is adjusted to be equal to the multiple of 8, in each of the display periods included in the first and second frames, and supplies the scanning signal to remaining scanning lines in a display period provided separately at an end of the second frame.

5. The display device of claim 1 , wherein:

the number of scanning lines to which the scanning signal is supplied in the display period included in the first and second frames is adjusted to be either x which is a multiple of 8 or y which is a multiple of 8 and is different from x; and

the scanning line drive circuit supplies the scanning signal to the x or y scanning lines in each of the display periods included in the first and second frames.

6. The display device of claim 1 , wherein:

the number of scanning lines to which the scanning signal is supplied in the display period included in the first and second frames is adjusted to be either X which is a multiple of 4 and not a multiple of 8, or Y which is a multiple of 4 and not a multiple of 8, and is different from X; and

the scanning line drive circuit supplies the scanning signal to the X or Y scanning lines in each of the display periods included in the first and second frames.

7. The display device of claim 1 , wherein:

the scanning line drive circuit is connected to a driver chip configured to output a control signal; and

a clock signal, which is one kind of the control signal output from the driver chip, is an alternating square wave signal alternating between a high-level potential and a low-level potential for every four scanning lines.

8. The display device of claim 7 , wherein the scanning line drive circuit starts an operation when an input of a start pulse signal, which is one kind of the control signal output from the driver chip, is received.

9. A method of driving a display device which comprises: a display portion comprising a plurality of electrodes arranged two-dimensionally on a substrate; a touch detection circuit which supplies a drive signal for touch detection to an electrode selected from among the plurality of electrodes, receives a signal from the selected electrode, and outputs a guard signal for reducing a parasitic capacitance to unselected electrodes; and a scanning line drive circuit which supplies a scanning signal to a plurality of scanning lines extending in the display portion, in which

a frame period, which comprises a display period in which the scanning signal is supplied to the plurality of scanning lines for image display, and a touch detection period related to sensing using the plurality of electrodes, includes a first frame and a second frame,

the method comprising:

adjusting the number of scanning lines to which the scanning signal is supplied in each display period included in the first and second frames such that a potential of the touch detection period included in the first frame matches a potential of the touch detection period included in the second frame.

10. The method of claim 9 , wherein the first and second frames each include a plurality of display periods and a plurality of touch detection periods, and the display period and the touch detection period occur alternately.

11. The method of claim 9 , wherein the potential of each of the touch detection periods included in the first and second frames is equal to a potential of an immediately preceding display period.

12. The method of claim 9 , further comprising:

adjusting the number of scanning lines to which the scanning signal is supplied in each of the display periods included in the first and second frames to be equal to a multiple of 8 uniformly; and

supplying the scanning signal to the scanning lines, the number of which is adjusted to be equal to the multiple of 8, in each of the display periods included in the first and second frames, and supplying the scanning signal to remaining scanning lines in a display period provided separately at an end of the second frame.

13. The method of claim 9 , further comprising:

adjusting the number of scanning lines to which the scanning signal is supplied in the display period included in the first and second frames to be either x which is a multiple of 8 or y which is a multiple of 8 and is different from x; and

supplying the scanning signal to the x or y scanning lines in each of the display periods included in the first and second frames.

14. The method of claim 9 , further comprising:

adjusting the number of scanning lines to which the scanning signal is supplied in the display period included in the first and second frames to be either X which is a multiple of 4 and not a multiple of 8, or Y which is a multiple of 4 and not a multiple of 8, and is different from X; and

supplying the scanning signal to the X or Y scanning lines in each of the display periods included in the first and second frames.

15. The method of claim 9 , wherein:

the scanning line drive circuit is connected to a driver chip configured to output a control signal; and

a clock signal, which is one kind of the control signal output from the driver chip, is an alternating square wave signal alternating between a high-level potential and a low-level potential for every four scanning lines.

16. The method of claim 15 , further comprising starting an operation when an input of a start pulse signal, which is one kind of the control signal output from the driver chip, is received.

17. A display device comprising:

a display portion comprising a plurality of electrodes which are arranged two-dimensionally on a substrate; and

a scanning line drive circuit which supplies a scanning signal to a plurality of scanning lines extending in the display portion, wherein

the scanning line drive circuit comprises:

a plurality of switch groups including a plurality of switches connected to the plurality of scanning lines, respectively; and

a plurality of shift registers provided for the plurality of switch groups, respectively,

a frame period, which comprises a display period in which the scanning signal is supplied to the plurality of scanning lines for image display, and a touch detection period related to sensing using the plurality of electrodes, includes a first frame and a second frame, and

the scanning line drive circuit selects one of the switch groups and one of the shift registers in sequence so that a potential of the touch detection period included in the first frame matches a potential of the touch detection period included in the second frame, and selects a switch of the plurality of switches included in the selected switch group one by one to supply the scanning signal to the scanning line connected to the selected switch.

18. The display device of claim 17 , wherein:

the number of scanning lines to which the scanning signal is supplied in each of the display periods included in the first and second frames is adjusted to be equal to a multiple of 8 uniformly; and

the scanning line drive circuit supplies the scanning signal to the scanning lines, the number of which is adjusted to be equal to the multiple of 8, in each of the display periods included in the first and second frames, and supplies the scanning signal to remaining scanning lines in a display period provided separately at an end of the second frame.

19. The display device of claim 17 , wherein:

the number of scanning lines to which the scanning signal is supplied in the display period included in the first and second frames is adjusted to be either x which is a multiple of 8 or y which is a multiple of 8 and is different from x; and

the scanning line drive circuit supplies the scanning signal to the x or y scanning lines in each of the display periods included in the first and second frames.

20. The display device of claim 17 , wherein:

the number of scanning lines to which the scanning signal is supplied in the display period included in the first and second frames is adjusted to be either X which is a multiple of 4 and not a multiple of 8, or Y which is a multiple of 4 and not a multiple of 8, and is different from X; and

the scanning line drive circuit supplies the scanning signal to the X or Y scanning lines in each of the display periods included in the first and second frames.