Through-the-lens thermometer apparatus

DETAILED DESCRIPTION Accordingly, it is an object of the present invention to provide a temperature measuring apparatus which is capable of non-contacting measurement.
It is another object of the present invention to provide a temperature measuring apparatus which is easily aligned with the measurement object.
It is still another object of the present invention to provide a temperature measuring apparatus which can be easily maintained in alignment with the measurement object.
It is yet another object of the present invention to provide a temperature measuring apparatus which has a display superimposed over the scene containing the measurement object.
It is yet still another object of the present invention to provide a temperature measuring apparatus which indicates to the user the exact area within which the instrument is sensitive.
It is still another object of the present invention to provide a temperature measuring apparatus which may be employed both in close-up and distant temperature measurement without parallax error.
Briefly, the present invention accomplishes these and other objects by providing a hand-held, portable, or stationarily mounted through-the-lens temperature measuring apparatus which employs two coaxially mounted optical systems having preferably the same focal length, one adapted to use with infra-red, the other adapted to use with visible light.
Infra-red energy is focused onto an infra-red detector whose output is amplified, linearized, digitized and displayed preferably in numerical form by a digital readout.
The field of view of the infra-red optical system is preferably smaller than the field of view of the visible light optical system, and reticule lines are preferably superimposed over the view through the visible light system to facilitate alignment of the apparatus with the object of interest.
The display is preferably superimposed on the view seen through the visible light optical system.
Coaxial mounting of the optical systems eliminates parallax error and enables simultaneous focusing of the two systems