Canon Patent Application: Dual Pixel APD sensor

This is some cool stuff. Canon has been researching APD sensors.  APD or Avalanche Photo Diode is different in the way that it records how much light the individual photodiode receives.  In a normal sensor, the more voltage, the more photons hit the photodiode.  However, with an APD, each photo triggers a pulse.  It can literally count the number of photons that hits the diode.  How accurate depends on elements such as the quantum efficiency of the sensor.  For instance, if the quantum efficiency is 30%, then for every 3 photons the photodiode would be triggered.

What you end up having is the ultimate in low light photography.

However, even with this, Canon isn't fully happy, so what we have here is an APD sensor arrangement that is designed as a dual pixel AF sensor.  In other words, this sensor is designed to go into your mirrorless cameras sometime in the future.  To hold all the logic that each pixel has, Canon stacks a digital processing layer underneath the photo diode layer.

Could this be the "next big thing"? hard to say, there's global shutter, and a bunch of other technology that may drive the sensors in tomorrow's cameras, however APD is certainly an area in which could led to some interesting capabilities.

Japan Patent Application 2019140537