Optical fingerprint sensor illumination using a display

1. A method of providing illumination for an optical fingerprint sensor integrated with a display, the display having a fingerprint (FP) pixel region and an outer pixel region exclusive of the FP pixel region, the method comprising:

processing image data in display driver circuitry configured to drive the display to present an image;

adjusting, via one or more of a gate driver circuit, a greyscale voltage circuit, a gamma circuit, and a voltage supply, a first brightness setting, during the processing of the image data, corresponding to both the FP pixel region and the outer pixel region to provide illumination for the optical fingerprint sensor;

determining, via a localized brightness control circuit, compensation amounts for individual pixel values of the outer pixel region based on the adjusted first brightness setting; and adjusting, via the localized brightness control circuit, a second brightness setting based on the determined compensation amounts, during the processing of the image data, corresponding to only the outer pixel region.

2. The method of claim 1 , wherein the step of adjusting the first brightness setting comprises:

switching from applying a first gamma curve to applying a second gamma curve during the processing of the image data.

3. The method of claim 1 , wherein the step of adjusting the first brightness setting comprises:

increasing greyscale voltage levels used by source line driver circuitry of the display driver circuitry during the processing of the image data.

4. The method of claim 1 , wherein the step of adjusting the first brightness setting comprises:

increasing an emission period of pixels in the display.

5. The method of claim 1 , wherein the step of adjusting the first brightness setting comprises:

increasing a difference between an anode supply voltage and a cathode supply voltage for light-emitting diode (LED) pixels of the display.

6. The method of claim 1 , wherein the step of adjusting the second brightness setting comprises adjusting only those digital samples representing the image data that correspond with the outer pixel region.

7. The method of claim 6 , wherein the step of adjusting the second brightness setting comprises adjusting the digital samples that correspond with the outer pixel region prior to storage in a buffer of the display driver circuitry or adjusting the digital samples stored in the buffer.

8. The method of claim 6 , wherein the step of adjusting the first brightness setting comprises increasing brightness of the image data corresponding to both the FP pixel region and the outer pixel region, and wherein the step of adjusting the second brightness setting comprises adjusting the digital samples that correspond with the outer pixel region using a transform that is an inverse of the increase in the brightness of the image data.

9. A processing system for driving a display having an integrated optical fingerprint sensor, the display having a fingerprint (FP) pixel region and an outer pixel region exclusive of the FP pixel region, the processing system comprising:

display driver circuitry configured to process image data to drive the display to present an image; and

FP illumination logic, disposed in the display driver circuitry, configured to:

adjust, via one or more of a gate driver circuit, a greyscale voltage circuit,

a gamma circuit, and a voltage supply, a first brightness setting, during processing of the image data, corresponding to both the FP pixel region and the outer pixel region to provide illumination for the optical fingerprint sensor;

determine, via a localized brightness control circuit, compensation amounts for individual pixel values of the outer pixel region based on the adjusted first brightness setting; and

adjust, via the localized brightness control circuit, a second brightness setting based on the determined compensation amounts, during processing of the image data, corresponding to only the outer pixel region.

10. The processing system of claim 9 , wherein the gamma circuit is configured to process the image data, wherein the FP illumination logic is configured to control the gamma circuit to switch from a first gamma curve to a second gamma curve during adjustment of the first brightness setting.

11. The processing system of claim 9 , further comprising:

source line driver circuitry configured to drive source lines in the display, wherein the greyscale voltage circuit is configured to provide greyscale reference voltages to the source line driver circuitry, and

wherein the FP illumination logic is configured to control the greyscale voltage circuit to increase the greyscale reference voltages during adjustment of the first brightness setting.

12. The processing system of claim 9 , wherein the gate driver circuit is configured to increase an emission period of pixels in the display during adjustment of the first brightness setting.

13. The processing system of claim 9 , wherein the voltage supply is configured to supply anode and cathode voltages to light-emitting diode (LED) pixels of the display, and

wherein the FP illumination logic is configured to control the voltage supply to increase a difference between the anode and cathode voltages during adjustment of the first brightness setting.

14. The processing system of claim 9 , wherein the FP illumination logic is configured to adjust the second brightness setting by adjusting only those digital samples representing the image data that correspond with the outer pixel region.

15. The processing system of claim 14 , wherein the FP illumination logic is configured to adjust the second brightness setting by adjusting the digital samples that correspond with the outer pixel region prior to storage in a buffer of the display driver circuitry or adjusting the digital samples stored in the buffer.

16. The processing system of claim 14 , wherein the FP illumination logic is configured to adjust the first brightness setting by increasing brightness of the image data corresponding to both the FP pixel region and the outer pixel region, and wherein the FP illumination logic is configured to adjust the second brightness setting by adjusting the digital samples that correspond with the outer pixel region using a transform that is an inverse of the increase in the brightness of the image data.

17. An input device, comprising:

an optical fingerprint sensor;

a display having the optical fingerprint sensor integrated therein, the display having a fingerprint (FP) pixel region and an outer pixel region exclusive of the FP pixel region; and

a processing system, coupled to the display, the processing system including:

display driver circuitry configured to process image data to drive the display to present an image; and

FP illumination logic, disposed in the display driver circuitry, configured to:

adjust, via one or more of a gate driver circuit, a greyscale voltage circuit, a gamma circuit, and a voltage supply, a first brightness setting, during processing of the image data, corresponding to both the FP pixel region and the outer pixel region to provide illumination for the optical fingerprint sensor;

determine, via a localized brightness control circuit, compensation amounts for individual pixel values of the outer pixel region based on the adjusted first brightness setting; and

adjust, via the localized brightness control circuit, a second brightness setting based on the determined compensation amounts, during processing of the image data, corresponding to only the outer pixel region.

18. The input device of claim 17 , wherein the gamma circuit is configured to process the image data, wherein the FP illumination logic is configured to control the gamma circuit to switch from a first gamma curve to a second gamma curve during adjustment of the first brightness setting.

19. The input device of claim 17 , wherein the gate driver circuit is configured to increase an emission period of pixels in the display during adjustment of the first brightness setting.

20. The input device of claim 17 , wherein the FP illumination logic is configured to adjust the second brightness setting by adjusting only those digital samples representing the image data that correspond with the outer pixel region.

21. The input device of claim 20 , wherein the FP illumination logic is configured to adjust the second brightness setting by adjusting the digital samples that correspond with the outer pixel region prior to storage in a buffer of the display driver circuitry or adjusting the digital samples stored in the buffer.

22. The input device of claim 20 , wherein the FP illumination logic is configured to adjust the first brightness setting by increasing brightness of the image data corresponding to both the FP pixel region and the outer pixel region, and wherein the FP illumination logic is configured to adjust the second brightness setting by adjusting the digital samples that correspond with the outer pixel region using a transform that is an inverse of the increase in the brightness of the image data.

23. A method of providing illumination for an optical fingerprint sensor integrated with a display, the display having a fingerprint (FP) pixel region and an outer pixel region exclusive of the FP pixel region, the method comprising:

processing image data in display driver circuitry configured to drive the display to present an image;

adjusting, via one or more of a gate driver circuit, a greyscale voltage circuit, a gamma circuit, and a voltage supply, a first brightness setting, during the processing of the image data, corresponding to only the FP pixel region to provide illumination for the optical fingerprint sensor;

determining, via a localized brightness control circuit, compensation amounts for individual pixel values of the outer pixel region based on the adjusted first brightness setting; and

adjusting, via the localized brightness control circuit, a second brightness setting based on the compensation amounts, during the processing of the image data, corresponding to only the outer pixel region.

24. The method of claim 23 , wherein the step of adjusting the first brightness setting comprises:

applying a first gamma curve to a first portion of the image data corresponding to only the FP pixel region using a first gamma circuit in the display driver circuitry, the first gamma curve increasing brightness of the first portion of the image data with respect to a second gamma curve.

25. The method of claim 24 , wherein the step of adjusting the second brightness setting comprises:

applying the second gamma curve to a second portion of the image data corresponding only to the outer pixel region using a second gamma circuit in the display driver circuitry.

26. A processing system for driving a display having an integrated optical fingerprint sensor, the display having a fingerprint (FP) pixel region and an outer pixel region exclusive of the FP pixel region, the processing system comprising:

display driver circuitry configured to process image data to drive the display to present an image; and

FP illumination logic, disposed in the display driver circuitry, configured to:

adjust, via one or more of a gate driver circuit, a greyscale voltage circuit,

a gamma circuit, and a voltage supply, a first brightness setting, during the processing of the image data, corresponding to only the FP pixel region to provide illumination for the optical fingerprint sensor;

determine, via a localized brightness control circuit, compensation amounts for individual pixel values of the outer pixel region based on the adjusted first brightness setting; and

adjust, via the localized brightness control circuit, a second brightness setting based on the determined compensation amounts, during the processing of the image data, corresponding to only the outer pixel region.

27. The processing system of claim 26 , wherein the display driver circuitry comprises a first gamma circuit configured to process a first portion of the image data corresponding only to the FP pixel region, and a second gamma circuit configured to process a second portion of the image data corresponding to only the outer pixel region, and wherein the FP illumination logic is configured to adjust the first brightness setting by utilizing a first gamma curve, the first gamma curve increasing brightness of the first portion of the image data with respect to a second gamma curve.

28. The processing system of claim 27 , wherein the FP illumination logic is configured to adjust the second brightness setting by utilizing the second gamma curve.