Temporal vision-guided energy minimization for portable displays

Abstract

This paper presents a novel backlight driving technique for liquid crystal displays. By scaling the intensity, frequency, and duty cycle of the backlight, this technique not only increases the perceived brightness but also prolongs the service time Of rechargeable batteries. The increased brightness comes from a perceptual effect of temporal vision - a brief flash appears brighter than a steady light of the same intensity, called Brucke brightness enhancement effect. The prolonged service time comes from the relaxation phenomenon - a lithium-ion battery lasts longer by pulsed discharge. Combining these two effects, a great amount of service time can be obtained at the cost of flickering. We performed visual experiments to parameterize the Brucke effect and derived an optimization algorithm accordingly. To demonstrate the potential energy savings of this technique, we profiled the power consumption of an Apple iPod and fabricated an LED driving module. Based on experimental data, 75% of energy consumption can be saved and the service time can be extended to 300%.