The reflective display technology boosts touchscreen brightness so much, maps and displays are as vivid in full bright sunlight as they are in shade.

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The display self-adjusts to become an ultra-high contrast e-book reader in bright sunlight, and a bright full-color backlit display in normal light.

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The XO-4 Touch will combine the XO's existing laptop functionality and sunlight-usable display with a full-fledged tablet mode.

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From May to March and September through November the sky is so full of migrating cranes, storks, pelicans and flamingos, it is hard for sunlight to peek through.

BBC: Where birds know no borders

You'll have to bump brightness up to max to make out the screen's contents when in direct sunlight, but even then it's advisable to seek shade for full clarity.

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The most compelling remains Pixel Qi -- a hybrid LCD technology that can be switched from a standard, full-color LCD backlit mode to a Kindle-like monochromatic reflective mode viewable in direct sunlight (while consuming 80% less power than standard LCDs).

ENGADGET: The e-Reader story of CES 2010