Abstract
An infrared (IR) temperature measurement system consists of a
sensor module and electronics as well as an optomechanical system that
guides IR radiation onto the sensor. The geometry and emissivity
of the optomechanics can affect the temperature reading. We show how
the traditional optomechanical design of the IR temperature measuring
systems produce inaccurate results when used in handheld mobile devices.
When the mobile device is not thermally stable and the measured targets
are significantly colder than the device, the measurement error can be
several degrees. Our new optomechanical design was optimised for
handheld mobile use, and its optics performance was modelled and
verified by prototyping. The temperature measurement and sensor
calibration is based on only two signals, namely the thermopile and thermistor
voltages of the IR detector. This is a very attractive method in
high-volume consumer products because no additional components are
needed to improve the measurement repeatability. The attainable
repeatability of the implemented IR temperature sensor on a correct
transferred calibration curve was better than ±0.5 °C in an operational temperature range from +13 to +49 °C and target range from +10 to +90 °C.
| Original language | English |
|---|---|
| Pages (from-to) | 161-167 |
| Number of pages | 7 |
| Journal | Sensors and Actuators A: Physical |
| Volume | 158 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2010 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- Infrared
- temperature
- sensor module
- mobile device
- calibration