Canon Patent Application: High Speed Stacked Sensor

This patent application from Canon is focusing on increasing the speed while managing the power requirements of a sensor. As the sensor increases in resolution, the problem of power management, and speed exasperates.  This patent application is attempting to make a sensor that is high speed, high in resolution, and lower or manageable power requirements.

This is a stacked sensor as you can see from the above diagram, with 201 and 202 being the two laminates.

The  solid-state image sensor 101 has a laminated structure including a first substrate 201 and a second substrate 202. The first substrate 201 includes a pixel unit 102, which is a pixel array in which unit pixels 203 are arranged in a matrix, and a control unit 204 that controls the pixels.

The bottom layer includes the ADC for converting the analog pixel values to digital, and also memory for both storing the values, and also the black level correction amounts.

As far as this patent, in Canon's words;

In the prior art, while the pixel signal can be read out at high speed, the number of vertical output lines in each pixel row increases, so that the number of constant current circuits to be connected increases and the power consumption increases. In particular, the increase in power consumption during Live View shooting greatly affects the number of shots that can be taken. Further, as the vertical output line of each pixel sequence increases, the scale of the correction circuit for correcting the offset to the pixel signal and the gain variation caused by the vertical output line increases. Correction circuit after the image sensor.

If it cannot cope with the increase in the vertical output line, it is necessary to mount a correction circuit on the image sensor. In this case, it is necessary to also mount a memory for storing the correction value, the power due to the read / write of the memory also increases, and the power consumption increases more and more.
The   present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an image pickup apparatus capable of achieving both high-speed reading of a pixel signal and reduction of power consumption.

Also of note, this patent application is also describing a DPAF sensor.  Photodiode 302a and 302b the pair of photodiodes that exist underneath each microlens.

Will something like this be featured in the high megapixel EOS R camera? it's entirely possible.  While Canon has experimented with high MP sensors before, this camera combined with DIGIC X could technically reach speeds of 10 fps at 80 to 90MP.  To process data that quickly of the sensor may require Canon to do a more clever sensor design.

I think personally we won't see this in the R5s but may see something of the sort in an R1.  The reason being is that this is a much more advanced sensor than Canon has ever produced commercially, it may require more time.

As with all patent applications, it's something that Canon is researching, there is no guarantees that it will end up in a product, and if it does, it may not even be recognizable.  However, this patent shows that Canon is continuing to do stacked sensor R&D.

Canon Patent Application 2021-002807