Canon patent application: Sensor stack with self contained memory

Canon is applying for an advanced sensor stacked sensor that includes three layers; the photoelectric conversion layer, the ADC conversion layer and a memory layer.

This would be a welcomed addition for super fast performance in both video and stills performance as we see with the Sony A9,etc.

From the patent application, machine translated.

A plurality of semiconductor substrates laminated each other, 
A picture element part by which a plurality of pixels were arranged by matrix form, 
A plurality of digital disposal circuits where each was provided with an analog signal processing part which performs predetermined processing before performing an AD translation by the aforementioned A/D converter at least to an A/D converter and a signal output from the aforementioned picture element part, 
It has a plurality of memories for memorizing a digital signal generated in said plurality of digital disposal circuits, 
An image sensor, wherein said plurality of digital disposal circuits are formed in a region of a second semiconductor substrate while the aforementioned picture element part is formed in a region of a first semiconductor substrate, and further said plurality of memories are formed in a region of the 3rd semiconductor substrate. 

Japan Patent Application 2018102002