Infrared thermogram camera and scanning means therefor

Claim 1

IN A THERMOGRAPH IN WHICH A FIXED INFRARED DETECTOR IS SCANNED ACROSS AN OBJECT TO BE THERMOGRAPHED IN THE FORM OF A RASTER, THE INFRARED DETECTOR OUTPUT IS TRANSFORMED INTO PROPORTIONAL VISIBLE LIGHT, AND THE VISIBLE LIGHT THUS PRODUCED IS SCANNED ACROSS A PHOTOGRAPHICALLY SENSITIVE SURFACE TO PRODUCE A PICTURE IN RASTER FORM CORRESPONDING TO THE TEMPERATURE OF THE OBJECT TO BE SCANNED, THE IMPROVEMENT WHICH COMPRISES, IN OPTICAL ALIGNMENT, (A) A PRISM-SHAPED ELEMENT WITH AN EVEN NUMBER OF EXTERNALLY REFLECTING SURFACES AND MEANS FOR CONTINUOUSLY ROTATING THE ELEMENT ABOUT ITS AXIS, THE ELEMENT BEING ORIENTED SO THAT THE INFRARED DETECTOR IS SCANNED ACROSS THE OBJECT TO BE THERMOGRAPHED IN A SERIES OF HORIZONTAL LINES BY ROTATION OF THE ELEMENT, (B) MEANS FOR TILTING THE PRISM-SHAPED ELEMENT ABOUT AN AXIS AT RIGHT ANGLES TO THE ANGLE OF ROTATION TO PRODUCE VERTICAL DISPLACEMENT OF THE HORIZONTAL LINES, (C) THE VISIBLE LIGHT SOURCE WHICH VARIES IN PROPORTION TO THE INFRARED DETECTOR OUTPUT BEING POSITIONED AND PROVIDED WITH OPTICAL MEANS SO THAT ITS RADIATIONS STRIKE AN OPPOSITE FACE OF THE SCANNING PRISM-SHAPED ELEMENT FROM THAT SCANNING THE INFRARED DETECTOR, AND ARE REFLECTED FROM SAID FACE ONTO THE PHOTOGRAPHIC SURFACE.