I'm also hoping that the pixels aren't all split in a left/right horizontal pattern, as the video shows, but that half of them are split vertically, because no one would want the AF system to be sensitive to horizontal contrast only.
Based on what I've read, including a statement from Chuck Westfall who was asked for clarification on the matter, they are all split in the same direction. That means the Dual Pixel CMOS phase AF system is a giant vertical line sensor, responsive only to horizontally-oriented details.
That's also what I surmised from Canon's video. However, I believe that in Portrait mode, the sensor would be only seeing vertical details unless the camera is able to switch between the two automatically, which doesn't seem likely - at least not in a mid range model.
I am wondering about things like banding, or a new type of artifact that might appear due to the divided photo sensors. That's pretty dependent on the actual fine details of how it works, something that we are not going to get from Canon.
As to patents, the sensor sounds like it uses this recent patent from Canon. http://translate.google.com/translate?twu=1?sl=auto&tl=en&u=http%3A//egami.blog.so-net.ne.jp/2012-08-12
After reading the patent document, I found it to be very complex, but it is almost certainly what we are seeing.
The wording is very engineering like, and looks like something intended for a mirrorless camera, which is why it was not anticipated to appear in a DSLR first.
While AF is said to be 30% faster, its obviously not yet going to beat conventional phase detect AF for speed. However, with more computing horsepower as might happen with a dual Digic 5+ processor or a newer version of Digic, we might see the mirror go away for good.