bichromatic interference pyrometer for determination of source temp. - has interferometric device with converging lens producing interference fringes converted to electric signal for comparison with reference

摘要

An bichromatic interference pyrometer is described for standardising the temperature of a source(5). If comprises an interferometric device (D) giving two images (S1, S2) of the sources (S), a convergent objective (o) which produces interference fruges from these two images in its focal image plane (F). TWo periodic gratings (G1, G2, superimposed in the focal image plane, each have a period corresponding to an interference fringe at a particular wavelength. A receiver (R) detects the total flux transmitted by the gratings. A system produces temporal variations of the total flux. transmitted; and an electronic device of the synchronous detection" type treats the photoelectric signal from the receiver using a reference signal. The centre of one grating may be clear while the other is opaque. The interferometric device may be of the polarising type. It may comprise two wollaston prisms whose separation may be modified.