Force touch sensor, display device and driving method thereof

1. A force touch sensor comprising a driving electrode, a sensing electrode, a plurality of piezoelectric material layers and at least one piezoresistive material layer, wherein,

the plurality of piezoelectric material layers and the at least one piezoresistive material layer are disposed between the driving electrode and the sensing electrode; and

the force touch sensor has a structure in which the driving electrode, a first one of the piezoelectric material layers, the piezoresistive material layer, a second one of the piezoelectric material layers and the sensing electrode are laminated in sequence.

2. The force touch sensor according to claim 1 , wherein, the force touch sensor comprises a plurality of driving electrodes, each of which extends along a first direction; and the force touch sensor comprises a plurality of sensing electrodes, each of which extends along a second direction; wherein the first direction intersects with the second direction.

3. The force touch sensor according to claim 1 , wherein, orthographic projections of the piezoelectric material layers and the piezoresistive material layer along a direction perpendicular to the piezoelectric material layer are completely overlapped with each other.

4. The force touch sensor according to claim 1 , wherein, a material of the piezoelectric material layers includes a piezoelectric ceramic material and/or an organic piezoelectric material.

5. The force touch sensor according to claim 1 , wherein, a material of the piezoelectric material layers includes a piezoelectric ceramic material that includes at least one selected from the group consisting of zinc oxide, aluminum nitride and lead zirconate titanate; and the organic piezoelectric material includes polyvinylidene fluoride.

6. A display device comprising a display panel and the force touch sensor according to claim 1 , wherein the force touch sensor is disposed on the display panel.

7. The display device according to claim 6 , wherein, the force touch sensor is integrated into the display panel.

8. The display device according to claim 7 , wherein, the display panel is a flexible organic light emitting diode display panel.

9. The display device according to claim 8 , wherein, the flexible organic light emitting diode display panel comprises a flexible substrate and a light emitting device disposed on the flexible substrate; and

the force touch sensor is disposed on one side of the flexible substrate close to the light emitting device.

10. The display device according to claim 8 , wherein, the flexible organic light emitting diode display panel comprises a flexible substrate and a light emitting device disposed on the flexible substrate; and

the force touch sensor is disposed on one side of the flexible substrate away from the light emitting device.

11. The display device according to claim 8 , wherein, the flexible organic light emitting diode display panel comprises a flexible substrate, a light emitting device disposed on the flexible substrate, and a thin film transistor disposed between the flexible substrate and the light emitting device; and

the force touch sensor is disposed between the flexible substrate and the thin film transistor.

12. The display device according to claim 8 , wherein, the flexible organic light emitting diode display panel comprises a flexible substrate, a light emitting device disposed on the flexible substrate and a thin film transistor disposed between the flexible substrate and the light emitting device; and the light emitting device comprises an anode, an organic material function layer and a cathode;

the force touch sensor is disposed between the thin film transistor and the anode; the thin film transistor, the force touch sensor and the anode are disposed in lamination, and the anode is electrically connected with a drain electrode of the thin film transistor through a via hole.

13. The display device according to claim 8 , wherein, the flexible organic light emitting diode display panel comprises a flexible substrate, a light emitting device disposed on the flexible substrate and a packaging thin film and a packaging cover plate for packaging the light emitting device; and

the force touch sensor is disposed between the packaging thin film and the packaging cover plate.

14. The display device according to claim 13 , wherein, the piezoelectric material layers and the piezoresistive material layer are disposed on a display area of the flexible organic light emitting diode display panel and cover the display area; and

the force touch sensor is transparent.

15. The display device according to claim 13 , wherein, the piezoelectric material layers and the piezoresistive material layer are disposed on a non-light-emitting area of the display area and have a network structure; and

both the driving electrode and the sensing electrode are transparent electrodes.

16. A method for driving a display device, wherein the display device comprises a display panel and a force touch sensor disposed on the display panel, said force touch sensor comprising a driving electrode, a sensing electrode, a piezoelectric material layer and a piezoresistive material layer, with the piezoelectric material layer and the piezoresistive material layer being disposed between the driving electrode and the sensing electrode,

the method comprising:

a touch stage, comprising applying a driving signal to the driving electrode line by line, receiving a touch sensing signal by the sensing electrode, and determining a touch position according to a signal change on the sensing electrode and the driving electrode to which the driving signal is applied; and

a pressure sensing stage, in which the piezoelectric material layer of an area under stress generates an electrical signal, while a resistance of the piezoresistive material layer of the area under stress decreases, comprising inputting a constant voltage signal into the driving electrode, allowing the sensing electrode to receive a voltage signal, and determining a pressure value at the touch position according to the voltage signal.

17. A display device comprising a display panel and a force touch sensor disposed on the display panel,

wherein the force touch sensor comprises a driving electrode, a sensing electrode, a piezoelectric material layer and a piezoresistive material layer, with the piezoelectric material layer and the piezoresistive material layer being disposed between the driving electrode and the sensing electrode;

wherein the force touch sensor is integrated into the display panel;

wherein the display panel is a flexible organic light emitting diode display panel;

wherein the flexible organic light emitting diode display panel comprises a flexible substrate, a light emitting device disposed on the flexible substrate and a thin film transistor disposed between the flexible substrate and the light emitting device; and the light emitting device comprises an anode, an organic material function layer and a cathode; and

wherein the force touch sensor is disposed between the thin film transistor and the anode; the thin film transistor, the force touch sensor and the anode are disposed in lamination, and the anode is electrically connected with a drain electrode of the thin film transistor through a via hole.