Patent ID: 8717547

Claim:
A process for producing an interface unit having comprising: receiving the interface unit comprising a conical spacing element and a contact element, the conical spacing element having an annular flange that defines a first reference surface for beaming in radiation, the contact element defining a second reference surface for emitting the radiation, the interface unit having an axis extending in the direction from the first to the second reference surface, the conical spacing element having an opening that holds the contact element and allows the contact element to be displaceable along the axis, setting an optical path length of the interface unit between the first and second reference surfaces along the axis, so that radiation of a given numerical aperture beamed in at the first reference surface exhibits a focus location that is predetermined with respect to the second reference surface in the direction of the axis, and fixing the set optical path length of the interface unit by fixing the contact element in its position along the axis such that the contact element is no longer displaceable along the axis.