Intra-optical light beam sighting system for an infrared thermometer

In an infrared thermometer of the transportable type, housing an infrared detector for generating a signal representative of the infrared energy transmitted to the thermometer from an object of which the temperature is to be measured and having a display for indicating the measured temperature;

• the improvement comprising:
• a source of visible light contained within said thermometer,
• an optical lens apparatus having equal effective spaced aperture means in said thermometer for directing said infrared energy onto said infrared detector and for transmitting said visible light out of said thermometer,
• the beam of infrared energy and visible light being congruent between said thermometer and said object whereby a visible intersection of the infrared field of view of the thermometer with said object is provided, and
• means separating said light source from said detector preventing said visible light from being incident on said infrared detector.