NON-CONTACT INFRARED THERMOMETER

Description

An
infrared thermometer
is a
thermometer
which infers temperature from a portion of the
thermal radiation
sometimes called
black-body radiation
emitted by the object being measured. They are sometimes called
laser thermometers
as a
laser
is used to help aim the thermometer, or
non-contact thermometers
or
temperature guns
, to describe the device's ability to measure temperature from a distance. By knowing the amount of
infrared
energy emitted by the object and its
emissivity
, the object's temperature can often be determined within a certain range of its actual temperature. Infrared thermometers are a subset of devices known as "thermal radiation thermometers".
Sometimes, especially near ambient temperatures, readings may be subject to error due to the reflection of radiation from a hotter body—even the person holding the instrument
[
citation needed
]
— rather than radiated by the object being measured, and to an incorrectly assumed emissivity.
The design essentially consists of a lens to focus the infrared
thermal radiation
on to a
detector
, which converts the radiant power to an
electrical
signal that can be displayed in units of temperature after being compensated for ambient temperature. This permits temperature measurement from a distance without contact with the object to be measured. A non-contact infrared thermometer is useful for measuring temperature under circumstances where
thermocouples
or other probe-type sensors cannot be used or do not produce accurate data for a variety of reasons.