Abstract: A device for converting the picture displayed on a screen (3) of a microfilm- or microfiche-reading device (1) into electric signals. In order to permit complete electronic reading of the screen, a bar (4) is provided which has a plurality of juxtaposed picture sensors (5) and which is movably guided by a guide element (6). For the purpose of fitting out the device subsequently, the device also has means for securing the guide element (6) in a specific position in relation to the screen (3).

Abstract: The invention relates to an interferometer head with a rigid bearer or casing to which a beam divider for the spatial division of laser light into a measuring and a reference beam and at least one recombination device are firmly secured (adhesively), where a reference beam guided by a reference path in the interferometer head and a measuring beam or part thereof guided by a movable measuring mirror of reflective measuring surface interfere to form at least one optical interference signal.

Abstract: The device described for the measurement, without physical contact, of the speed, displacement distance and/or range of a reflecting object has a laser diode as light source, transmission and receiver optics for aiming the laser light from the laser diode at the object and for feeding part of the laser light reflected by the object back to the laser resonator, and a detector unit for detecting and analyzing the laser light emitted by the laser diode. Fitted to determine the modulation frequency of the laser light, which is frequency-modulated as a function of the feedback to the laser resonator, is a frequency discriminator, a photodiode and a processing circuit with a spectrum analyzer.

Abstract: An interferometer suitable for length measurements, comprising a laser light source, a beam splitter to divide light stemming from the laser light source into a measuring beam and a reference beam, and recombination means at which the reference beam being guided along a reference path and the measuring beam interfere. The measuring beam travels along a measuring path that leads over a movable measuring reflector and partly through a gaseous ambient medium. The interferometer further comprises photodetector means to analyze optical interference signals stemming from the recombination means. At least one static etalon of a known length is provided to determine or compensate for variable environmental conditions (variable refractive index) of the ambient medium. The etalon comprises two reflection surfaces and is illuminated by light stemming from the laser light source. The space lying inbetween these reflection surfaces is filled with the ambient medium.

Abstract: In an interferometer for measuring displacements of a movable structural component, comprising a measurement interferometer arrangement (1), a partial beam traverses a measurement branch of variable optical length and is guided by an adjustable reflector system (11) connected to the movable structural component. The measurement interferometer arrangement (1) is arranged, together with the adjustable reflector system (11) including the whole measurement branch, in a sealed housing (3) which also contains a wavelength measuring device (2) for measuring the wavelength of the partial beam which travels through the measurement branch in a gaseous medium. A ventilator device (14) produces an air current in the housing (3), so that identical conditions, in particular identical temperature, pressure and humidity, always prevail in the medium in the measurement branch and in the spatially separate wavelength measuring device (2).

Abstract: The invention concerns a device for generating light, in particular light for use in length measurement using an interferometer. The frequency of the laser light emitted is controlled as a function of the wavelength in the surrounding gaseous medium (air) in such a way that the wavelength in the air remains constant. The light source in this device is a laser diode. Located external to the laser resonator is a device for feeding back to the resonator, at selected frequencies, light emitted by the laser diode.