Patent ID: 7374714

Claim:
A process for shaping a body with elongate structures on its surface, comprising: providing a preform having the elongate structure, the elongate structures being elongate along one direction; heating the preform in at least one region by radiation which has a spectral distribution such that at most half of a radiation power is absorbed during a single pass through the preform, whereby radiation is impinged on the at least one region after it has been reflected or scattered and whereby radiation components which have already passed through the at least one region to be heated without being absorbed are directed back onto the preform by being scattered or reflected and thereby contribute to heating, whereby a maximum temperature difference along a region cross section in the at least one region being less than 0.5° C. is effected; and drawing the preform until at least part of the preform has adopted a cross section which substantially corresponds to a final cross-sectional shape of the body, the preform being drawn at a viscosity in the range from approximately 10 5 dPas to 10 10 dPas.