Method of making a rotational optical arrangement, and the optical arrangement made by the method

An optical arrangement including:

• a base for rotation about a mechanism-induced rotational axis;
• an optical pattern layer having a center axis and having at least two portions that each have a different optical characteristic, one of the base and the optical pattern layer having a surface perpendicular to an interface normal direction;
• means for fixing the optical pattern layer to the base for rotation therewith such that the center axis is aligned against radial offset with the rotational axis;
• a mechanism for rotating the base and the optical pattern layer around the mechanism-induced rotational axis;
• and
• means for fixing the base to the mechanism such that the interface normal direction is aligned against skew from the mechanism-induced rotational axis;
• wherein the means for fixing the base to the mechanism includes an adhesive that sets once the interface normal direction is aligned;
• and
• wherein the mechanism includes a shaft, and the base includes an opening, the opening has a taper, the shaft has an end that has a size equal to the opening at some location along the taper, and the base rests upon the shaft at the location where the opening equals the shaft end.