Abstract: A camera tube for thermal imaging is disclosed comprising an entrance window of an electrically conductive material, a target for converting the thermal image, and an electron beam system for scanning the target. Incident thermal radiation is modulated by means of a mechanical chopper functioning as a modulator directly in front of the entrance window. The entrance window is electrically isolated from the target and is preferably grounded. By so doing, the target is shielded against electrical influences due to the modulator.

Abstract: A target plate for converting information-carrying thermal radiation to a storable or visual form is a carrier comprising the conversion layer having a grid thereon formed by adjoining regular polygons the borders of which are defined by an array of holes in the conversion layer. The holes may be aligned points or rectangular slots, and are arranged in the conversion layer to minimize lateral thermal transfer within the conversion layer, thereby separating the conversion processes within the conversion layer and resulting in improved resolution of the converted image. For use in a pyroelectric thermal vidicon an electrode layer is applied to one surface of the target plate.

Abstract: A Zr-C sintered body is charged with H.sub.2 to form zirconium hydride within the body and such body is positioned in working association with a heating means within an electronic tube, such as a vidicon tube, which utilizes hydrogen as a supporting gas. During an operation of such tube, the sintered body is heated and releases an amount of H.sub.2 therefrom as a function of the temperature while the sintered body acts as a getter for any residual gases within the tube, other than H.sub.2, at elevated operating temperatures.

Abstract: A passive infrared alarm device evaluates the changes in infrared radiation level of a monitored room or a monitored portion of a room for alarm purposes. In accordance with the invention, an infrared sensing element is employed toward which an optical reflector directs infrared radiation emanating from one or more angles in a room to be monitored. An infrared filter is mounted in the path of the reflected infrared radiation before such radiation reaches the sensing element. The infrared filter is designed to absorb infrared radiation below a predetermined minimum wavelength, and additional means is provided for partially absorbing infrared radiation below the predetermined minimum at the reflector.

Abstract: The invention relates to a "warm light reflector", which reflects infrared radiation and absorbs visible light. More specifically, a reflecting layer of, for example, gold carries a double layer of PbS, which is constructed of one smooth layer and of one fine-flocked layer of agglomerates.The disclosed warm light reflector finds particular application in infrared measurement technology, preferably in a passive infrared alarm generator.