Non-contact infrared (IR) thermometers use infrared technology to measure the surface temperature of objects so measurement of hot, hazardous, or hard-to-reach surfaces without contaminating or damaging the object is easy. IR energy emitted from a measured object passes through an optical system of the thermometer and is converted to an electrical signal at the detector which is then displayed as a temperature reading. Easily compared to the human eye, the optics is the lens of the eye through which the radiation from the object reaches the photosensitive layer (retina) via the atmosphere. After some conversion, this information is sent to the brain for processing.