System and method for detecting grip of a touch enabled device

1. A device comprising:

a front face and a back face, the back face opposite the front face;

a display on the front face of the device;

a controller configured to control the display;

a grid based capacitive sensor integrated with the display, wherein the sensor is configured to sense touch input on the display; and

a circuit in communication with the sensor, the circuit configured to:

perform mutual capacitive detection based on scanning one axis of the grid based capacitive sensor;

detect a heatmap based on the mutual capacitive detection;

identify a thumb or palm on a pre-defined portion of the display based on the heatmap;

detect capacitance (C BD ) between the user and the device based on the heatmap;

identify that a user is touching the back face of the device based on accumulated averages of the C BD being above a pre-defined threshold, wherein the accumulated averages are accumulated over a plurality of refresh cycles of the sensor including refresh cycles during which the thumb or palm is on the pre-defined portion of the display;

detect that the user is gripping the device based on identifying the thumb or palm on the pre-defined portion of the display and based on detecting when the user is touching the back face of the device; and

report the gripping detected to the controller.

2. The device of claim 1 , wherein the C BD is detected based on a number of touched junctions in the heatmap and amplitude of touch junctions in the heatmap.

3. The device of claim 1 , wherein the pre-defined portion of the sensor is along at least one edge of the display.

4. The device of claim 1 , wherein the pre-defined portion of the sensor is dynamically adjusted based on an orientation of the display.

5. The device of claim 1 , wherein the report is input to an application running on the device or to a graphical processing unit of the device.

6. The device of claim 1 , wherein the C BD is also detected based on pre-defined constants, wherein the pre-defined constants are related to physical properties of the grid based capacitive sensor and are defined based on empirical data.

7. A method comprising:

performing mutual capacitive detection based on scanning one axis of a grid based capacitive sensor integrated with a display of a device, wherein the display occupies at least a portion of a first surface of the device, wherein the first surface is opposite a second surface of the device, and wherein the sensor is configured to sense touch input on the display;

detecting when the user is touching a pre-defined portion of the display with a thumb or palm based on a heatmap determined from the mutual capacitive detection;

detecting capacitance (C BD ) between the user and the device based on the heatmap;

detecting when the user is touching the second surface of the device based on accumulated averages of the C BD being above a pre-defined threshold, wherein the accumulated averages are accumulated over a plurality of refresh cycles of the sensor including refresh cycles during which the thumb or palm is on the pre-defined portion of the display;

detecting that the user is gripping the device based on identifying the thumb or palm on the pre-defined portion of the display and based on detecting when the user is touching the back face of the device; and

reporting the gripping detected to a controller of the device.

8. The method of claim 7 , wherein the C BD is detected based on a number of touched junctions in the heatmap and amplitude of touch junctions in the heatmap.

9. The method of claim 7 , wherein the pre-defined portion of the sensor is along at least one edge of the display.

10. The method of claim 7 , wherein the pre-defined portion of the sensor is dynamically adjusted based on an orientation of the display.

11. The method of claim 7 , wherein the report is input to an application running on the device or to a graphical processing unit of the device.

12. The method of claim 7 , wherein the pre-defined threshold is 250 pF.

13. The method of claim 7 , wherein the C BD is also detected based on pre-defined constants, wherein the pre-defined constants are related to physical properties of the grid based capacitive sensor and are defined based on empirical data.

14. The method of claim 7 , wherein the C BD is also detected based on spatial spread of a touched area on the heatmap.