The Canon patent announces the possibility of building a Dual Pixel BSI sensor

Canon has recently filed a new patent focusing on the design of image sensors, which is very similar to the design  of Sony’s BSI (Backside Illumination ) sensors. Canon’s new patent combines BSI technology with Dual Pixel technology; This issue may eventually lead to a leap forward in night-time shooting, dynamic range and reading speed.

Canon’s new sensor design is pictured in a new patent officially filed by the company. This patent does not explicitly state that we are on the side of the BSI sensor; However, when comparing the Canon sensor with the BSI sensors, the similarities are striking and cannot be ignored. 

In the following design, which belongs to Sony, you can see the structure of the BSI sensor:

^{This image belongs to Sony BSI sensors}

In 2008, Sony developed this type of CMOS sensor. Unconfirmed reports say that since January 2019, Canon has made efforts to design a sensor similar to Sony’s BSI sensors. At the time, only the possibility of building a Dual Pixel BSI sensor was mentioned; But we have never seen the design of this sensor depicted in a separate patent. The new patent shows that Canon intends to build a Dual Pixel BSI sensor more seriously than we thought.

Normally, lenses are made with a formula similar to how the human eye works; In this way, the lens is placed in front of the wiring and we see a photodetector on the back. The BSI sensor uses the same elements but changes the way they are arranged; In this way, the photodiode (Photodiode) is placed in front of the wiring.

With the conventional method called “front lighting”, the elements and the wiring reflect part of the light, reducing the signal that can be recorded. BSI sensors overcome this problem by weakening the uniformity of response ; But at the same time, their performance is improving in a dimly lit environment.

BSI sensors have recently become suitable products for improving imaging in low light environments, as well as improving the dynamic range. This type of sensor has another advantage, and that is to increase the reading speed.

The Sony a9 camera can record a large number of frames per second in all-electronic mode in a quiet way without experiencing blackouts. Experts say one of the main reasons why the camera in question has such a useful capability is the presence of a BSI-CMOS sensor. Keep in mind that Sony has proprietary technologies that can extract information from the sensor twice as fast as competitors; But the benefits that BSI offers in such situations can never be ignored.

A closer look at Canon’s patent reveals that the structure depicted is very similar to the outline of BSI sensors. In a part of the patent, we read: “A structure built in a beneficial way.”