Melexis - Medical Technology | Issue 33

MEDICAL-GRADE TEMPERATURE SENSORS

Medical infrared temperature sensors are accurate and allow non-contact measurement for fast operation. These are key features in situations where people need to be screened for fever symptoms in an eﬃcient and precise way. From complex calibration to medical standards to fulﬁll, manufacturers face multiple challenges in the design as well as in the assembly of such a medical devices. Depending on the speciﬁc needs of the customer, Melexis has several solutions available.

Melexis IC solutions for temperature sensing

Aiming to facilitate the integration of the IC, Melexis not only oﬀers sensors with digital output but also factory-calibrated infrared temperature ICs, allowing medical device manufacturers to design and build medical-grade infrared body thermometers in a fast and simple way in line with medical standards, meeting the medical temperature accuracy of ±0.2 °C.

Depending on the speciﬁc needs of the customer, Melexis has several solutions available.

Thanks to its tiny QFN package size (3 x 3 x 1 mm), the M L X 9 06 32 is well suited for applications such as contactless ear thermometers or any wearable or portable applications. Miniaturized far-infrared sensors are typically sensitive to thermal interferences, however the innovative M L X 9 06 32S L D -D CB -000 mitigates this eﬀect with smart compensation algorithms.

When a narrower ﬁeld of view (FoV) is required, for larger distance between the sensor and the object under a test, the popular M L X 9 06 14ES F -D CC-000 in TO-CAN package is the preferred choice with its 35° ﬁeld of view.

The M L X 9 06 14E S F -D CI -000 variant has a mere 5° ﬁeld of view and therefore allows maximum detection distance. This feature is useful in systems such as automated fever screening of children at school or employees at the factory gate.

ACCURATE SKIN & EAR TEMPERATURE SENSING FOR WEARABLE APPLICATIONS

Continuous health monitoring is becoming part of our daily lives, from remote patient monitoring to wearable health-care devices for self-check and activity tracking. The 2020 health care crisis only accelerated this trend. Of course, the accuracy, reliability and repeatability of the data is crucial for a correct follow-up.

A study* has shown that skin temperature measurement using contact thermometry is facing systematic measurement variations.

In sharp contrast with contact thermometers, contactless infrared-based thermometers inherently do not suffer from issues related to poor thermal contact quality.

Study extract*:

Results: ...Results from these studies indicated minor (<0.5 °C) to practically meaningful (>0.5 °C) measurement bias within the subgroups of attachment type, applied pressure, environmental conditions, and sensor type.

The 95% LoA were often within 1.0 °C for in vivo studies and 0.5 °C for physical models. …

Conclusions: Setup variables and conditions of use can influence the measured temperature from contact Tskin sensors and thus key setup variables need to be appropriately considered and consistently reported.

Contact vs contactless sensing