It's patent day, and we have another stacked sensor patent. What's interesting about this one is how detailed it is. It's likely we're going to see some stacked sensor technology in a Canon product sooner than later.
Canon News interprets Japan Patent Application 2018-014519:
This patent is about offloading heat generated from the processing substrate. Heat of any sort is bad for an image sensor, as that turns into noise. As you move more processing into the image sensor substrates you increase the heat generated.
This is the most detailed stacked sensor patent application that I've seen to date, and it gets really specific on the size, depth and measurements of the indidvidual sections of the sensor stack. It also demonstrates in it's embodiments a back side illuminated sensor as the photoelectrical substrate. Read more at Canon News