Energy-Adaptive Display System Designs for Future Mobile Environments

The utility of a mobile computer, such as a laptop, is largely constrained by battery life. The display stands out as a major consumer of battery energy, so reducing that consumption is desirable. In this paper, we motivate and study energy-adaptive display sub-systems that match display energy consumption to the functionality required by the workload/user. Through a detailed characterization of display usage patterns, we show that screen usage of a typical user is primarily associated with content that could be displayed in smaller and simpler displays with significantly lower energy use. We propose example energy-adaptive designs that use emerging OLED displays and software optimizations that we call dark windows. Modeling the power benefits from this approach shows significant, though user-specific, energy benefits. Prototype implementations also show acceptability of the new user interfaces among users.