Just because Apple patent something doesn't mean they'll actually use it in a product. And with the way the patent systems in general are broken (the US one in particular), it may be that they haven't done anything new or innovative in this field.

And in other news, Nintendo have developed a glasses-free display for their new handheld console (the 3DS) which they announced in the summer and I believe is due for release in March.

If Apple's display is actually holographic, I'd be interested to see it, but this seems far too gimmicky for Apple, and it is probably something they have patented "just in case", rather than being tech they plan to use.