Abstract: By means of a method of bonding a first part and a second part together, in which at least one thin layer is provided on at least one of the parts and is activated by a slight polishing treatment, after which the likewise activated surface of the second part is bonded to the activated surface of the first part by mechanical wringing, a rigid bond can be obtained in which the spacing between the parts can be accurately adjusted.

Abstract: By using special dies, lenses from glass can be manufactured with great precision. Such dies are manufactured from quartz glass. Quartz glass can be worked with the required shape accuracy and the required smoothness, for example, by a polishing treatment succeeded by sputtering.

Abstract: A method and device are provided for machining transparent glass and vitreous material by means of a single point cutting tool. A portion of the workpiece to be worked is heated integrally and uniformly by a first heat supply, which is spread along the workpiece, to the softening temperature, and simultaneously the surface to be worked is locally heated in the region of the cutting area at the moment of material removal to a depth equal to the cutting depth by a second concentrated heat supply which is superimposed on the first heat supply. All this is provided in such a manner that a turning operation, as well as simultaneously therewith and immediately thereafter a relaxed flow of the work surface, takes place. By means of the method according to the invention, it is possible to turn workpieces of glass and vitreous materials so that the work surface has a high dimensional accuracy, as well as an optical surface quality in particular, such as a smooth and transparent surface.

Abstract: A method of breaking optical fibers, a fiber being scored over the entire circumference in a plane perpendicular to the fiber axis. By subsequently applying a predetermined axial tensile force to the fiber, fracture is initiated over the entire circumference of the fiber. As a result of this, fibers with a comparatively large diameter can be broken in such a way that a mirror zone is obtained across the entire fracture area. Circumferential scoring also ensures the required accuracy in respect of the perpendicular orientation of the fracture plane relative to the fiber axis.