Canon Patent Application: Canon researching anti-static coatings for Canon RF lenses

This is an interesting patent application, what Canon is concerned about is that dust has a greater chance of adhering to the back element of a lens as you decrease the distance between the rear element of the lens and the sensor.  Because of this, they are looking at adding an anti-static coating to the rear elements of lenses to help reduce the amount of dust that collects on the rear elements.  With the rear elements of the Canon RF mount being larger than before with the EF mount, it stands to reason that they may collect even more dust than simply because of the distance is reduced.

In awkward machine translated Japanese to English, Canon said this:

When distance becomes short, the influence concerned may become for example, less minor [ even if garbage has adhered to the lens in the case of an interchangeable lens, if the distance from an imaging surface to a lens is a comparatively long lens, the influence of the garbage to the image quality of the photoed image is minor, but ]. For example, garbage is easily reflected in a taken image. 

Also in the imaging device disclosed in the Patent document 1, if the distance from an imaging surface to a lens becomes short, a possibility that the garbage which did not adhere to a solid state imaging element surface will adhere to a lens will become high. 

Japan Patent Application 2019-008147