| 摘要 |
409,073. Photophones. ZEISS, C., [Firm of], Carl-Zeiss-Strasse, Jena, Germany. Dec. 17, 1932, No. 35814. Convention date, Dec. 23, 1931. [Class 40 (v).] Some parts of an optical signalling apparatus are used for both transmission and reception, and the necessary changes in the other electric and optical parts are made by a single switch k, Fig. 1. For transmission an electromagnet f<1>, traversed by the signals, moves a prism d to and from a reflecting-surface c<1> and thus modulates the reflection of light incident from a source g. For reception a constant current is passed through the electromagnet of such strength the prism is pressed tightly against the reflecting surface so that the received incident light passes uninterruptedly to the selenium cell h. According to a modification, Fig. 2, the light from a source r is modulated by a movable diaphragm p. The side opposite the source has an inclined surface v which, in the position where the light from the source r is completely cut off, deflects the received light to a light-sensitive cell u.
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