Touch detection device and display device having touch detection function which comprise touch driver updating drive synchronizing signal for producing touch drive signal based on signal input from display driver

1. A display device having touch detection function, comprising:

a plurality of drive electrodes;

a plurality of detection electrodes provided to generate capacitances with the drive electrodes;

a display driver configured to perform a touch scanning drive by supplying a touch drive signal having pulses for detecting proximity of an external object to a target drive electrode to be driven, which is selected from the drive electrodes;

a touch driver configured to transmit and receive a signal to and from the display driver, output a drive synchronizing signal to the display driver for producing the touch drive signal, and acquire detection signals from the detection electrodes at timing corresponding to inputting of the touch drive signal, to detect the proximity of the external object; and

display pixels configured to perform display based on display signals and a display drive signal,

wherein the touch driver determines at least one of the number of pulses of the drive synchronizing signal and a pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver, the touch driver measures a first time based on the signal received from the display driver, makes a calculation using the first time and a constant to determine a longest time during which the drive synchronizing signal is allowed to be output, and also determines a maximum number of pulses which are supplied in the longest time, as the number of pulses of the drive synchronizing signal,

the display driver repeatedly alternately performs a display scanning drive and the touch scanning drive in a time sharing manner, and in the display scanning drive, the display diver supplies the display drive signal to the drive electrodes in turn.

2. The display device having touch detection function, according to claim 1 , wherein in the touch scanning drive, the display driver supplies the touch drive signal to the same drive electrode as the display driver supplies the display drive signal in the display scanning drive, the touch drive signal and the display drive signal being supplied to the same drive electrode in a time sharing manner.

3. The display device having touch detection function, according to claim 2 , wherein in units of at least one frame, the touch driver determines at least one of the number of pulses of the drive synchronizing signal and the pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver.

4. The display device having touch detection function, according to claim 1 , wherein in units of at least one frame, the touch driver determines at least one of the number of pulses of the drive synchronizing signal and the pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver.

5. A touch detection device comprising:

a plurality of drive electrodes;

a plurality of detection electrodes provided to generate capacitances with the drive electrodes;

a display driver configured to perform a touch scanning drive by supplying a touch drive signal having pulses for detecting proximity of an external object to a target drive electrode, which is selected from the drive electrodes; and

a touch driver configured to transmit and receive a signal to and from the display driver, output a drive synchronizing signal to the display driver for producing the touch drive signal, and acquire detection signals from the detection electrodes at timing corresponding to inputting of the touch drive signal, to detect the proximity of the external object,

wherein at least one of the number of pulses of the drive synchronizing signal and a pulse width of each of the pulses of the drive synchronizing signal is determined based on the signal received from the display driver,

the touch driver determines at least one of the number of the pulses of the drive synchronizing signal and the pulse width of the each of the pulses based on the signal received from the display driver, and

the touch driver measures a first time based on the signal received from the display driver, makes a calculation using the first time and a constant to determine a longest time during which the drive synchronizing signal is allowed to be output, and also determines a maximum number of pulses which are supplied in the longest time, as the number of pulses of the drive synchronizing signal.

6. The touch detection device, according to claim 5 , further comprising display pixels configured to perform display based on display signals and a display drive signal,

wherein the display driver repeatedly alternately performs a display scanning drive and the touch scanning drive in a time sharing manner, and in the display scanning drive, the display diver supplies the display drive signal to the drive electrodes in turn.

7. The touch detection device, according to claim 6 , wherein in the touch scanning drive, the display driver supplies the touch drive signal to the same drive electrode as the display driver supplies the display drive signal in the display scanning drive, the touch drive signal and the display drive signal being supplied to the same drive electrode in a time sharing manner.

8. The touch detection device, according to claim 7 , wherein in units of at least one frame, the touch driver determines at least one of the number of pulses of the drive synchronizing signal and the pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver.

9. The touch detection device, according to claim 6 , wherein in units of at least one frame, the touch driver determines at least one of the number of pulses of the drive synchronizing signal and the pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver.

10. The touch detection device, according to claim 5 , further comprising display pixels configured to perform display based on display signals and a display drive signal,

wherein the touch driver determines at least one of the number of pulses of the drive synchronizing signal and a pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver, and

the display driver repeatedly alternately performs a display scanning drive and the touch scanning drive in a time sharing manner, and in the display scanning drive, the display diver supplies the display drive signal to the drive electrodes in turn.

11. The touch detection device, according to claim 10 , wherein in the touch scanning drive, the display driver supplies the touch drive signal to the same drive electrode as the display driver supplies the display drive signal in the display scanning drive, the touch drive signal and the display drive signal being supplied to the same drive electrode in a time sharing manner.

12. The touch detection device, according to claim 11 , wherein in units of at least one frame, the touch driver determines at least one of the number of pulses of the drive synchronizing signal and the pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver.

13. The touch detection device, according to claim 10 , wherein in units of at least one frame, the touch driver determines at least one of the number of pulses of the drive synchronizing signal and the pulse width of each of the pulses of the drive synchronizing signal based on the signal received from the display driver.