This patent application is possibly beyond our pay grade to read through, however the high level summary is that it's a new anti-reflective coating that is designed to reduce ghosting and flare on elements designed to correct the color of light as it passes through the lens.
The lens in which they show in the embodiment is a 400mm 2.8. In this case the film is applied to 101, 102 and 103 surfaces.
Focal Length 390.06
F number 2.8
Half angle of View 3.17
Image Height 21.64
Lens length 365.06
US Patent Application 20180149773
As with all patent applications this may not come to fruition, or in the case of small improvements, many of them may be combined to form the next generation of super telephoto lenses.