Optical unit and its use

Not Applicable An optical unit () comprising a plurality of optical elements, a receiving structure () with a plurality of element supports () for receiving the optical elements. The element supports () are in the form of a plate or shell or tube, whose dimensions are greater than the dimensions of the optical elements to be received, and is connected to another element support. At least one element support () comprises temperature elements () that can be heated and/or cooled. The optical unit () furthermore comprises a control unit for driving the temperature elements () in order to locally change the temperature of the at least one element support () so as to influence in a controlled manner the shape of the at least one element support ().