What’s so special in the image shown above? There is no optical viewfinder and no mirror at all! Sony fulfilled a patent for a camera that has a new sensor which contains pairs of phase detection pixels. (Click here to see the original patent on freepatentsonline). There is no need for any mirror (translucent or classic mirror) that reflects light on a dedicated AF sensor. The advantage of such technology is that you can have phase detection on mirrorless systems and unlike the translucent technology you have no light loss because of the semitransparent mirror. Phase detection autofocus is much faster than contrast autofocus. See the image below to see how Sony includes the AF pixels on the sensor:
The only “problem” with the described solution is that you need more pixels on a sensor and you will probably have to use less or smaller RGB pixels compared to classic RGB Bayer sensors.
My two cent on that. It will not take very long to see the technology to be used on real Sony cameras. Simply because that IS the right technology for all mirrorless cameras that want to focus as fast as professional DSLR cameras.