| 摘要 |
517,526. Discharge lamps; luminescent materials ; infra-red telephony and telegraphy. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. July 20, 1938, No. 21602. Convention date, July 23, 1937. [Classes 39 (i) and 40 (iii)] A device for producing radiation of infra-red or longer wave length, which may be used for signalling, comprises an evacuated chamber containing a layer of material capable of producing such radiation when excited by electron or ionic bombardment, by X-rays or by a glow discharge, such as a selenide or telluride of zinc, cadmium, or mercury or a mixture of these substances, and exciting means of such nature within the chamber. A mercury telluride produces radiation up to several thousands of a millimetre in wave length. Activating metals such as copper, silver, platinum or yttrium are added to influence the sensitivity of the substances and the wave length produced. The layers of the infra red luminescent substance may be mounted on the inner wall of an evacuated glass or quartz envelope G. An accelerating electrode B, a control grid if desired, and an indirectly heated cathode K are mounted inside the envelope. Instead of the grid B, metallic particles may be embedded in the layer S and connected to a source of positive voltage. Applications to glow discharge tubes and envelopes made mainly of metal are also described. Further, electrons emerging from a, cathode can be used first for producing X-rays and these then employed for exciting the layer. The device may be used as a transmitter for telegraphy or telephony on infra-red waves by fitting it with radiation control means, e.g., by controlling its energization, and placing it at the focus of a parabolic reflector. At the receiving end the radiation may be picked up by a bolometer or ultra short wave demodulator also placed in a reflector.
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