A radiation thermometer with sighting means for identifying the radiation target area

摘要

A radiation thermometer comprises a thermal radiation detector assembly 15 having an operative surface area responsive to thermal radiation; a focussing optics assembly 18 adapted to focus both thermal radiation and visible light and form a focussed image of the operative surface area on a focal plane defining a target region TR from which thermal radiation is detected; a visible light source assembly 20 comprising at least one visible light source 21 and a mask 22 adapted to exhibit an illuminated pattern of visible light; and a radiation splitter 30 to transmit/ deflect the thermal radiation and visible light differently, so as to pass them along two equal-length paths such that the focussing optics forms an image of the illuminated pattern on the focal plane to mark the location of the target region. The illuminated pattern includes a primary illumination region having the same lateral extent as the operative surface area of the thermal radiation detector assembly and positioned such that its image is co-incident with the target region; and at least one secondary illumination region being configured such that its image is located outside the target region.