Patent ID: 8749538

Claim:
A display device comprising: an auxiliary light source configured to provide supplemental light to a reflective display; a sensor system configured to determine an illuminance of ambient light illuminating the reflective display; and a controller in communication with the sensor system, the controller configured to adjust the auxiliary light source to provide an amount of supplemental light to the reflective display based at least in part on the illuminance of the ambient light, wherein the amount of supplemental light: remains substantially the same on average or substantially increases on average in response to increasing illuminance of the ambient light when the illuminance of the ambient light is below a first threshold, and substantially decreases on average in response to increasing illuminance of the ambient light when the illuminance of the ambient light is above a second threshold that is greater than or equal to the first threshold, wherein the amount of supplemental light has a peak value in a range from 20 nits to 30 nits for illuminance of the ambient light that is above the first threshold and below the second threshold.