Electronic device and method of processing user actuation of a touch-sensitive input surface

1. An electronic device, comprising:

a proximity-sensitive touch sensor array which extends along an input surface of the electronic device and having a conductive pattern, and

a processing device coupled to the touch sensor array, the processing device being configured to:

sense capacitance values of the conductive pattern of the touch sensor array,

determine a variation in perpendicular distance of a finger from the input surface as a function of position on the input surface in a spatially resolved manner from the sensed capacitance values,

process the sensed capacitance values to determine a finger angle at which the finger is directed towards the input surface and an actuation position on the input surface, wherein the finger angle defined by the variation in perpendicular distance is derived from a spatial gradient of the sensed capacitance values,

derive a finger orientation from the sensed capacitance values, the finger orientation defining a direction of a projection of the finger onto the input surface, and

use the determined finger angle and the derived finger orientation when processing user actuation of a touch-sensitive input surface.

2. The electronic device of claim 1 ,

wherein the processing device is configured to determine the finger angle based on self-capacitance measurements of the plurality of rows and self-capacitance measurements of the plurality of columns.

3. The electronic device of claim 2 ,

wherein the processing device is configured to derive the finger angle from a gradient of self-capacitances of rows and a gradient of self-capacitances of columns.

4. The electronic device of claim 2 ,

wherein the processing device is configured to carry out a row scan to perform the self-capacitance measurements for the plurality of rows and a column scan to perform the self-capacitance measurements for the plurality of columns, and to derive the finger angle from data obtained in the row scan and data obtained in the column scan.

5. The electronic device of claim 1 , further comprising a force sensor configured to determine a force with which a finger is pressed against the input surface or multiple fingers are pressed against the input surface,

wherein the processing device is configured to establish an offset-corrected actuation position as a function of the actuation position and the finger angle by adding an offset to the actuation position on the input surface or subtracting an offset from the actuation position on the input surface, wherein the processing device is configured to establish a magnitude of the offset as a function of the finger angle, and determine a force offset as a function of the finger angle and to derive an offset-corrected force value from an output of the force sensor and the force offset.

6. The electronic device of claim 5 ,

wherein the processing device is a controller coupled to the conductive pattern and configured to provide the offset-corrected actuation position to an application processor of the electronic device.

7. The electronic device of claim 5 ,

wherein the processing device is configured to derive a direction of the force sensed by the force sensor based on the finger angle.

8. The electronic device of claim 5 ,

wherein the electronic device is configured to perform an operation in response to the offset-corrected force value.

9. The electronic device of claim 5 ,

wherein the processing device is configured to establish the magnitude of the offset such that it approximately corresponds to a discrepancy between a position where a user thinks that the finger has touched the input surface and the actuation position determined based on the sensed capacitance values.

10. The electronic device of claim 5 ,

wherein the processing device is further configured to establish a direction of the offset as a function of the finger orientation.

11. The electronic device of claim 5 , further comprising:

an application processor coupled to the processing device to receive the offset-corrected actuation position, the application processor being configured to perform an operation which is selected in dependence on the offset-corrected actuation position.

12. The electronic device of claim 5 , wherein the processing device is configured

to detect a multi-touch input operation in which at least one further finger touches the input surface at least one further actuation position,

to determine at least one further finger angle at which the at least one further finger is directed towards the input surface, and

to establish at least one further offset-corrected actuation position as a function of the at least one further actuation position and the at least one further finger angle.

13. The electronic device of claim 1 ,

wherein the processing device is configured to predict an expected fingerprint of the finger using the finger angle.

14. The electronic device of claim 1 ,

wherein the actuation position comprises a z-coordinate which depends on a force applied by the finger onto the input surface,

wherein the processing device is configured to establish an offset-corrected z-coordinate as a function of the z-coordinate of the actuation position and the finger angle.

15. The electronic device according to claim 1 , wherein the finger angle comprises an angle between a plane of the input surface and a longitudinal axis of the finger.

16. A method of processing a user actuation of an input surface of an electronic device, the method comprising:

sensing capacitance values of a conductive pattern of a proximity-sensitive touch sensor array which extends along the input surface of the electronic device,

determining a variation in perpendicular distance of a finger from the input surface as a function of position on the input surface in a spatially resolved manner from the sensed capacitance values,

processing the sensed capacitance values to determine a finger angle at which a finger is directed towards the input surface and an actuation position on the input surface, wherein determining the finger angle includes deriving the finger angle defined by the variation in perpendicular distance from a spatial gradient of the sensed capacitance values,

deriving a finger orientation from the sensed capacitance values, the finger orientation defining a direction of a projection of the finger onto the input surface, and

using the determined finger angle and the derived finger orientation when processing user actuation of a touch-sensitive input surface.

17. The method of claim 16 , further comprising predicting an expected fingerprint of the finger using the finger angle.

18. The method of claim 16 , wherein the actuation position comprises a z-coordinate which depends on a force applied by the finger onto the input surface, the method further comprising establishing an offset-corrected z-coordinate as a function of the z-coordinate of the actuation position and the finger angle.

19. The method according to claim 16 , wherein the finger angle comprises an angle between a plane of the input surface and a longitudinal axis of the finger.