Another lens patent from Tamron: 10-24mm f/3.5-4.5 DiII VC USD
In addition to the 20mm f/2 Di VC USD, Tamron recently also filed a patent for a 10-24mm f/3.5-4.5 DiII VC USD zoom lens. The patent contains calculations for a 9-18mm f/3.5-4.5 DiII VC USD lens as well.