Abstract: An optical rotary joint having a housing, a hollow shaft, a bevel gear, a prism and two collimators. The housing includes two sections, each holding a collimator and separated by a gap in an axial direction from each other and rotatable against each other and around the center axis. The hollow shaft is aligned with the center axis, and has two ends extending into the housing sections. The housing sections are supported via bearings by the hollow shaft. The hollow shaft further contains a prism holder with a Dove prism. The bevel gear is located in the gap between the housing sections and includes two wheels at the housing sections in mesh with two third wheels, which have an axis oriented radially to the center axis and fixedly attached to the hollow shaft, such that a rotation of the housing sections against each other results in a rotation of the hollow shaft with half of the angular speed.

Abstract: An optical rotary joint having a housing, a hollow shaft, a bevel gear, a prism and two collimators. The housing includes two sections, each holding a collimator and separated by a gap in an axial direction from each other and rotatable against each other and around the center axis. The hollow shaft is aligned with the center axis, and has two ends extending into the housing sections. The housing sections are supported via bearings by the hollow shaft. The hollow shaft further contains a prism holder with a Dove prism. The bevel gear is located in the gap between the housing sections and includes two wheels at the housing sections in mesh with two third wheels, which have an axis oriented radially to the center axis and fixedly attached to the hollow shaft, such that a rotation of the housing sections against each other results in a rotation of the hollow shaft with half of the angular speed.