A tri wavelength diffracting modulation element, a TWDM imager, and methods of temporally and spatially modulating by using the same are disclosed. However, the alignment film is not formed in a seal portion. According to the invention, the rod is configured as an interior rod with an interior sheathing applied to it. The first welding torch is configured to carry out a welding process and at least a second welding torch is configured to carry out a cold-metal transfer welding process with a forward-backward movement of a welding wire, and that a device for synchronizing the welding processes carried out by the at least two welding torches is provided. 01-20% of a nonionic surfactant, 0. 1 to 14 vol % throughout the production steps.