The patent application was first filed in October, 2009, and has been made public just this week. Apple might have invented this new kind of display technology and they now just want to prevent any other company to implement it in their own products that may potentially compete with theirs.
Or, they might actually be working on their own iDevice that will sport such a screen. Now, they have their own iBookstore. But many people say that the iPad makes a very poor reading device with its glossy, eye-straining and power-consuming LCD. The current iPhone has such a small screen with an incredibly low-viewing angle.
E-ink, on the other hand makes such amazing e-book readers. The Amazon Kindle, like other e-readers, has an almost infinite battery life, it doesn't strain your eyes and looks just like paper. However, it does not support smooth moving video and animations because of a really low refresh rate.
If the iPad 3 comes with a hybrid screen like this, it will get the best of both worlds. It will have a lighted, colorful LCD that runs all the apps, plays video and all that. It will also change to an electronic paper display, on which you will be able to read your books.
This might help Apple get into the e-book industry as well, maybe even competing with Amazon.