US Patent 7898712 Risley integrated steering module

A Risley integrated steering module is disclosed. The beam steering device consists of an outer assembly rotatable about an axis, and an inner assembly rotatable about the axis and positioned radially within the outer assembly. The beam steering device also includes a first prism connected to the outer assembly and a second prism connected to the inner assembly, and a stationary assembly, with the outer and inner assemblies being rotatable about the portion of the stationary assembly. In an alternative embodiment, the inner assembly rotates within the stationary assembly. The beam steering device also consists of beam expansion optics carried by either the inner assembly or the stationary assembly.