Apple has filed a patent for an iPhone display that has two backlights. The idea is to have a second low-power backlight that will be always on. So you can easily check if you have messages, or other stuff without having to turn the main display on.
I think it's time Apple thought about using an OLED - in which no backlight is required, and if you just make a small screensaver with the time and messages status - it will draw very little power.
Posted: Nov 24,2008 by Ron Mertens
A company files a patent for many reasons. Most of the time, the patent doesn't even get used. Apple might just to be doing it to protect their intellectual property.