Appareil détecteur de radiations infrarouges

摘要

780,594. Detecting infra-red. BRINRO, Ltd. Aug. 31, 1954 [Sept. 14, 1953], No. 25279/54. Class 40 (3). [Also in Group XXXVI] Apparatus for detecting infra-red comprises a condenser the capacity of which varies in response to infra-red rays and which forms part of an electronic device for producing an audible indication of the ray intensity. As shown (Fig. 1) the apparatus comprises a pair of condensers 7, 71, both of which have dielectric constants variable by incident infra-red. A "Lenard" phosphor which may include zinc and/or cadmium combined with sulphur selenium or tellurium may be used. Condenser 7 is arranged to receive infra-red rays while condenser 71 is shielded from them and is used to provide temperature compensation. Each condenser controls the oscillation frequency of one of a pair of electron-coupled oscillators I and II which, in the absence of infra-red, both oscillate at the same frequency. Infra-red incident on condenser 7 changes the frequency of oscillator I. The outputs of the oscillators are combined in a mirror 3 and the beat frequency is audible in a telephone receiver 4. In a modification (Fig. 4) the condensers are replaced by a network comprising tube 17, condenser C1 and infra-redsensitive resistor R, the whole circuit acting as a capacity. Resistor R may be of PbS, PbSe or PbTe. Fig. 3 shows the mounting of the infrared sensitive condensers 7, 71 in the housing. Capacitor 7 is subject to the action of infra-red passing through a filter 5 which may be closed by a shutter 14. Capacitor 71 is mounted behind a screen and coils L1, L2 are carried by support plates 15, 16. The housing 8 may be mounted in a soldier's helmet or on a rotating support such as an automatically controlled gun.