Touch screen display and method of driving the touch screen display with signal adjustment
View Patent ↗A touch screen display device is described that includes a display panel, a display driver, a sensor circuit and a combination unit. The display panel has a plurality of display elements arranged between a first and a second electrode layer. The display driver is arranged for providing display signals comprising a common display signal and an input control signal to the display panel. The sensor circuit is arranged for providing a probe signal and a shield signal mutually having the same phase and frequency and for generating a touch signal in response to the output signal received from the first electrode layer. The combination unit provides a drive signal to the first electrode layer derived from the common display signal and the probe signal, and further provides an output control signal for the display panel from the input control signal and the shield signal.
1. A touch screen display device comprising:
a display panel comprising a plurality of display elements arranged between a first electrode layer and a second electrode layer having respective pixel electrodes for the display elements;
a display driver for providing display signals to the display panel, said display signals comprising:
a common display signal, and
an input control signal for controlling the display panel;
a sensor circuit for providing a probe signal and a shield signal, and for generating a touch signal in response to an output signal received from the first electrode layer, wherein the phase and frequency of the probe signal are identical to the phase and frequency of the shield signal; and
a combination unit for providing a drive signal to the first electrode layer derived from the common display signal and the probe signal, and for providing the output control signal for controlling the display panel, wherein the output control signal is derived from the input control signal and the shield signal.
2. The touch screen display device according to claim 1 , wherein the display panel includes an active matrix layer for driving the pixel electrodes, wherein the input control signal is an input control signal for the active matrix layer, and wherein the output control signal is for the active matrix layer.
3. The touch screen display device according to claim 2 , wherein the pixel electrodes are coupled to a first side of a respective storage capacitor, a second side of said storage capacitor being coupled to a storage line and wherein the output control signal is a signal for driving the storage line.
4. The touch screen display device according to claim 1 , wherein the combination unit comprises a first multiplexer for deriving the drive signal by multiplexing the common display signal and the probe signal and a second multiplexer for deriving the output control signal by multiplexing the input control signal and the shield signal.
5. The touch screen display device according to claim 1 , wherein the combination unit comprises a first superposition unit for deriving the drive signal by superposing the common display signal and the probe signal and a second superposition unit for deriving the output control signal by superposing the input control signal and the shield signal.
6. The touch screen display device according to claim 1 , wherein the display driver and the sensor circuit have small signal drivers for those signals that are combined by the combination unit and wherein the combination unit has a respective amplifier for amplification of the combined signals.
7. The touch screen display device according to claim 1 , wherein the first electrode layer extends beyond the display area.
8. The touch screen display device according to claim 7 , wherein the first electrode layer extends beyond the display area over an extension distance that is in a range between 5 to 30% of the size of the display area in the direction of the extension.
9. The touch screen display device according to claim 1 , wherein the shield signal is applied to another conductive structure of the display panel.
10. The touch screen display device according to claim 1 , wherein the shield signal is applied to all conductive structures of the display panel having a large overlap with the first electrode layer.
11. A method of driving a touch screen display device, the display device comprising a display panel comprising a plurality of display elements arranged between a first electrode layer and a second electrode layer having respective pixel electrodes for the display elements, the method comprising the steps of:
providing display signals for the display panel, comprising a common display signal and an input control signal for the display panel;
providing a probe signal and a shield signal, wherein the phase and frequency of the probe signal are identical to the phase and frequency of the shield signal;
generating a touch signal in response to an output signal received from the first electrode layer;
providing a drive signal to the first electrode layer derived from the common display signal and the probe signal, and
providing the output control signal for the display panel, wherein the output control signal is derived from the input control signal and the shield signal.
12. The method of claim 11 wherein the display panel includes an active matrix layer for driving the pixel electrodes, wherein the input control signal is an input control signal for the active matrix layer, and wherein the output control signal is for the active matrix layer.
13. The method claim 12 , wherein the pixel electrodes are coupled to a first side of a respective storage capacitor, a second side of said storage capacitor being coupled to the storage line and wherein the output control signal is a signal for driving the storage line.
14. The method of claim 11 wherein a first multiplexer, during the providing a drive signal step, derives the drive signal by multiplexing the common display signal and the probe signal, and wherein a second multiplexer, during the providing an output control signal step, derives the output control signal by multiplexing the input control signal and the shield signal.
15. The method of claim 11 wherein a first superposition unit, during the providing a drive signal step, derives the drive signal by superposing the common display signal and the probe signal, and wherein a second superposition unit, during the providing an output control signal step, derives the output control signal by superposing the input control signal and the shield signal.
16. The method of claim 11 , wherein both a display driver that provides the display signals to the display panel, and a sensor circuit that provides the probe signal and shield signal, have small signal drivers for those signals that are combined, and
wherein a respective amplifier is provided for amplification of the combined signals.
17. The method of claim 11 , wherein the first electrode layer extends beyond the display area.
18. The method of claim 15 , wherein the first electrode layer extends beyond the display area over an extension distance that is in a range between 5 to 30% of the size of the display area in the direction of the extension.
19. The method of claim 11 , further comprising a step of providing the shield signal to another conductive structure of the display panel.
20. The method of claim 11 , further comprising a step of providing the shield signal to all conductive structures of the display panel having a large overlap with the first electrode layer.