This diagram describes a new camera system with two semi-transparent mirrors and a high-resolution EVF that will be implemented in the next a77 and a750 models from Sony:
“Yesterday Sony explained the new system that will be used for the incoming a77 (the a750 will use a regular SLR design). Practically the are using two semi-transparent mirrors and a high-resolution EVF to reinforced the live image. They are using a reflexive technology design called 70/30, between each semi-transparent mirrors. The final image in the viewfinder will have 30% of original image and 70% of electronic reinforced image through the new EVF."
