基本信息
摘要：1,189,225. Measuring movement. LABORATOIRE CENTRAL DES INDUSTRIES ELECTRIQUES. July 4, 1967 [July 4, 1966], No.30822/67. Heading G1A. Small movements are detected or measured by a device comprising a photo-conductive and Piezo-electric solid, or thin film semi-conductor crystal, a light-source for illuminating at least one face of the crystal, electrical contacts on either side of the one face or faces, and means for varying in accordance with the movement the area of the face or faces illuminated whereby the frequency of oscillation in the output circuit of the crystal is varied. The crystal which may be a cadmium sulphide mono-crystal and parallel to the hexagonal axis is made to oscillate by the application of a stabilized D. C. voltage and changes of frequency arising from changes of area are detected to indicate the movement of a mask between the source and the crystal. White or green light may be used and intensities are specified. The green light or light of a shorter wavelength may be produced by an electro-luminescent diode. A load resistor is included in series with the crystal, and the end of the crystal connected to the negative terminal may be shaped to concentrate the electrical field and thus facilitate the commencement of oscillation. Practical embodiments in which the light source and the crystal are mounted in an evacuated and temperature controlled chamber are described. The application of the invention to seismographic measurements is referred to. The crystal may be mounted in a beryllium oxide substrate and the contacts may be formed of successive films of indium and of indium/gallium eutectic.
摘要附图：
