The traditional optomechanical design of the IR temperature measuring systemswas shown to produce inaccurate results when directly ported into handheld mobile devices.
Traditional systems were optimised for situations in which the device is thermally stable and when the measured targets were significantly warmer than the device.
When these assumptions are not valid, the measurement error can be several degrees. Based on first principles, an optomechanical designwasoptimised for handheld mobile use.
The system performance was modelled and then tested by a laboratory prototype.
The attainable repeatability of the implemented sensor prototype using correct calibration curves measured by 2.5 ◦C intervals was better than ±0.5 ◦C in an operational temperature range from +12.6 to +49.3 ◦C and a target range from +10 to +90 ◦C.
Utilizing the correct calibration curve is a necessity in order to attain a repeatability of better than ±1 ◦C in the IR temperature measurement with an operational temperature range of −40 to +80 ◦C and a target temperature range of −40 to 120 ◦C required typically in mobile devices.