Does the glowing apple logo on the back of the screen spend extra battery energy?
I am curious to know if the glowing apple logo of a notebook wastes any electricity.
Someone said it only use the screen LED light, is it true?
It does get light from the backlight. Light it gets from the backlight is less light that is available for your display. if the apple were not there less light would be taken away from the front display. Conceivable, then, you could operate with a lower backlight illumination setting saving energy. In that sense it would save battery energy. But the difference is so small you may not notice.