Infrared temperature sensor system for mobile devices

Kimmo Keränen (Corresponding Author), Jukka-Tapani Mäkinen, Pertti Korhonen, Eveliina Juntunen, Veli Heikkinen, Jakke Mäkelä

Research output: Contribution to journalArticleScientificpeer-review

25 Citations (Scopus)

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 languageEnglish
Pages (from-to)161-167
Number of pages7
JournalSensors and Actuators A: Physical
Volume158
Issue number1
DOIs
Publication statusPublished - 2010
MoE publication typeA1 Journal article-refereed

Keywords

  • Infrared
  • temperature
  • sensor module
  • mobile device
  • calibration

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