Abstract: An apparatus for frequency conversion of a laser (1) in which one or more non-linear crystals (5, 6) are arranged in the laser beam (3), and the necessary power density is produced by an arrangement of a dedicated focussing lens (4), in the region of the focal point (14), with a collimator, which minimizes the divergence of the laser beam (3), an optical corrector, which shapes the cross section of the laser beam (3). A single focussing lens (4) is provided behind which a corrective lens (7) is arranged at an angle to the optical axis and at a distance which corresponds roughly to the sum of both focal lengths such that the focussing lens (4) and the corrective lens (7) form the collimator and the corrective lens (7) also functions as a corrector. In this way a laser is produced which is characterized by small size and a simple and economical construction.

Abstract: A drilling or milling head, especially for printed circuit board milling machines and/or engraving machines, having a collet chuck (11) which can be actuated by a rapid change mechanism and which is driven by a transmission. The collet chuck is opened by an axial displacement relative to a clamping sleeve (50), with the force necessary for the displacement being transmitted via a friction clutch. The transmission includes a ball bearing (9) whose balls (12) are moved around a common axis in a concentric manner by a driving part (6) fixed on a motor drive shaft (5). In addition, the balls are mounted between two bearing surfaces (13, 14) which are aligned in a concentric manner with regard to the axis and which have a circular cross-section. The balls are at least partially engaged with the bearing surfaces in a positive manner.

Abstract: The invention relates to methods for measuring the sorbate content in substrates, using a sensor with a measuring chamber. Said chamber contains a support medium whose partial pressure of sorbate is determined in order to determine the sorbate content of the substrate. According to the first method, the temperature of the support medium is varied up to a value at which the partial pressure of sorbate in the measuring chamber no longer varies with the temperature of the support medium, and slightly over this value. This partial pressure of sorbate is then used to determine the sorbate content of the substrate. According to the second method, the temperature of the support medium is kept essentially constant and the speed at which the partial pressure of sorbate of the support medium approaches the stable end value is determined.

Abstract: A coating for the structured production of conductors on the surface of electrically insulating substrates, in particular for producing sensor elements and printed circuit boards. The coating is formed from a doped tin oxide layer having the composition Sn.sub.1-(y+z) A.sub.y B.sub.z O.sub.2, in which A is Sb or F and B is In or Al. The relative proportions in the coating of the dopants antimony (or fluorine) and indium (or aluminum) are defined by the limits 0.02<y+z<0.11 and satisfy the condition 1.4<y/z<2.2. The coating can be structured by ablation using electromagnetic laser radiation in the wavelength range 157-1064 nm. The creates an economical means for high resolution and waste-free structuring of insulating channels in thin, electrically conductive layers having high chemical, mechanical and thermal resistance on glass or ceramic substrates.