Canon Patent: Quarter Wave Element Lenses

In this patent application (2025-040503), Canon further explores this reflective and transmission phased layer to produce some wild lens designs.  I will have to come up with a name for this element, as I have a feeling we will see a lot of it. Now, it's still possible that Canon may never do these lenses with this layer, as we have no idea how difficult it is to mass produce.

Look at the other patent application on some really esoteric ultra-wide lenses using this technique.

All of these lenses, though, would never be in an RF mount configuration.  It would be impossible.  The lens almost touches the sensor, having a back focus distance of only .1mm.  These lenses may make it into a dedicated camera system, but with a .1mm back focus distance, I struggle to even think of a camera system these could be used with, as any vibration or thermal expansion and the element would be touching the sensor.

Looking at the below example, which is a 50mm F1.5 lens for a full-frame sensor but with a back focus distance of .1mm, you can see the HM1, HM2, and QWP elements reflect incoming light and bend it so that the image circle is large enough for a full-frame sensor. That is an amazing feat when the elements are close to the sensor.

This is a Patent Application

As with all patent applications, this is a look into Canon's Research and may not end up in an actual product.