Dynamic Backlight Scaling for Power Minimization in a Backlit TFT-LCD

Description

Dynamic backlight scaling (DBS) technology is a set of techniques that reduce energy consumption of backlit liquid crystal displays (LCDs). The methods use pixel transformation and are designed to minimize image distortion. They can implement any piecewise linear grayscale spreading (transmittance) function by suitably adjusting the brightness and contrast of the displayed image. The approaches take advantage of human visual system characteristics and try to minimize the incurred distortion between the perceived brightness values of the individual pixels in the original image and those of the backlight-scaled image. Experimental results have provided power savings ranging from 35 to 45% with an effective distortion rate of 5%, and from 55 to 65% for a 20% distortion rate.

Advantages

• Significantly higher power savings compared to previously reported backlight dimming approaches.

• Optimization is based on human visual system characteristics, rather than luminance values.

• Minimizes image distortion.

• Power savings are great enough to extend battery life in devices with TFT LCDs by a factor of two or more, without much performance overhead or display quality degradation.

Applications

Laptop computers, handheld portable computers, and other battery-powered devices with liquid crystal displays (LCDs) applicable for both still images and video.

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