An assembly is adapted for being employed in an optical navigation device, such as that used on a computer or mobile communications device. The assembly includes a housing device and an optical device, wherein the housing device includes a receiving section for receiving the optical device. The receiving section has a first and a second opening. The housing device has first and second vertical registration features for aligning the optical device with the housing device. The first and second vertical registration features are spatially associated with the first and second opening respectively.