FIBRE-OPTIC THERMAL DETECTOR Russian patent published in 2012 - IPC G01K11/00 G02B6/26 

FIELD: physics.

SUBSTANCE: thermal detector has an illuminating and a receiving light guide, the first ends of which are connected to a light source and a photodetector, and second ends to a guided Y fibre-optic splitter, the common input/output of which is fitted with a heat-sensitive element, having a mirror surface and made in form of an opaque blind made from material with shape memory effect, attached by one end to the butt-end of a measuring light guide. The blind is given reversible shape memory at flexure. In the initial state, below the direct martensitic transformation temperature, the free end of the blind is tightly pressed by the mirror side to the butt-end of the measuring light guide, thereby completely covering the aperture of the light guide. In a state higher than the inverse martensitic transformation temperature, the free end of the blind deviates by an acute angle from the plane of the butt-end of the measuring light guide.

EFFECT: faster operation owing to reduction of the size and weight of the heat-sensitive element, simplification, reduced loss when transmitting reflected light flux to the receiving light guide and high sensitivity owing to significant change in intensity for small temperature changes.

5 dwg