Display with optical sensor for brightness compensation

An electronic device comprising:

• a display panel having an array of pixels;
• an optical sensor that is positioned beneath the display panel, wherein the optical sensor is configured to obtain pixel brightness information;
• and
• control circuitry configured to compensate brightness values for the array of pixels for a given frame based on the pixel brightness information obtained by the optical sensor, wherein the array of pixels is configured to display a watch face image, wherein the optical sensor is overlapped by first pixels in the array of pixels that have a first brightness while displaying the watch face image, and wherein the optical sensor is overlapped by second pixels in the array of pixels that have a second brightness that is different than the first brightness while displaying the watch face image.

A method of operating an electronic device having a display with pixels and an optical sensor, the method comprising:

• displaying images using the display;
• using the optical sensor, measuring a first brightness level of ambient light that passes through the display to the optical sensor;
• performing pixel aging testing operations, wherein performing the pixel aging testing operations comprises using the optical sensor to measure a plurality of second brightness levels each associated with a different subset of pixels in the display;
• and
• performing first global brightness testing operations, wherein performing the first global brightness testing operations comprises using the optical sensor to measure a third brightness level associated with a test image;
• and
• performing second global brightness testing operations, wherein performing the second global brightness testing operations comprises using the optical sensor to measure a fourth brightness level associated with the test image and wherein at least one month elapses between performing the first and second global brightness testing operations.