Abstract: A device (1) for programmed spot treatment of a body with a beam of rays, particularly a laser beam (7), using a lens system (4), in which the point of impact of the beam (7) describes a predetermined pattern on the surface of the body particularly a lacquer sealed rotary screen printing stencil 3a, as a result of a relative movement of the body with respect to the device. According to the invention the device (1) has means for maintaining a constant predetermined distance between the center of the lens system (4) and the center of the point of impact of the beam (7) of rays with the surface of the body.

Abstract: Described is a tensioning roller which can expand under the influence of an inflating pressure and which is used for supporting a medium which is to be treated with high-energy radiation.Such a tensioning roller comprises at the outside a thin walled metal cylinder or sleeve which for the purpose of achieving an increased radial expandability according to the invention is provided with axial slots which are evenly distributed around the periphery of the sleeve.The invention also concerns a device for treating a medium with high-energy radiation which comprises a tensioning roller as described.

Abstract: A method of making a perforated metal foil, especially for screen printing, comprises applying to a metallic surface a photosensitive layer, exposing the photosensitive layer through a screen pattern, developing the exposed photosensitive layer to remove portions surrounding dots of the photosensitive material, and electrodepositing a metal upon the surface in the region surrounding the dots. Prior to or during a galvanic deposition of the screen metal on the surface, the dots of photosensitive material are swelled so that the tendency of the perforation boundaries to be encrusted with metal is reduced and the perforations resulting in the screen have substantially the same cross sections and sizes as the dots of the photosensitive material.