Sony published this video that contains two parts: The first is an interview with the engineer that lead the Sony A1 sensor design. The second part is with another engineer talking about the new 2 layer sensor. This new architecture approximately doubles saturation signal level relative to conventional image sensors, widens dynamic range and reduces noise, thereby substantially improving imaging properties. The new technology’s pixel structure will enable pixels to maintain or improve their existing properties at not only current but also smaller pixel sizes.
I wonder if we will get this new kind of sensor on the future A1II :)