Translucent Backs for Laptops?
Which suggests an interesting possibility. Why not make the whole lid out of a translucent material, thus providing a brighter background at no cost in power. It would only work in a bright environment—but then, that's when it is most needed.
Eventually it occurred to me to check the setting for screen brightness. With that turned up, the rest of the screen is readable too. But the translucent back still seems as though it might make sense.
Perhaps under some circumstances it would be a disadvantage, although I'm not sure what those would be. If so, use the high tech version. Two layers of polarizing material, one of which can have its polarization switched, vertical to horizontal or left handed to right, to make the combination opaque.