The most prominent application for infrared thermometers is measuring body temperature to check for fever and illness. There are three main types of IR fever thermometers: ear thermometers, forehead thermometers, and non-contact, distance-read thermometers. Measurement accuracy depends on the calibration accuracy of the thermometer and how accurately the temperature measured on the patient’s exterior can be translated into an internal body temperature. For most medical applications, a measurement accuracy of ±0.2°C or better is required.
The MLX90615 from Melexis is the world’s first intelligent infrared thermometer integrated into the ultra small TO-46 package commonly used in the manufacture of ear thermometers. This ultra-small and cost effective, non-contact thermometer delivers a fully calibrated digital temperature reading achieved by integrating an infrared sensor with a custom signal conditioning chip in a TO-46 package.
The sensing element in the MLX90615 is a silicon chip with a thin, micro-machined membrane heated by the infrared radiation of the object. This proven Melexis technology has been applied to industrial and automotive temperature measurement challenges for many years. A custom built signal conditioning chip amplifies and digitizes the minute voltages generated by the thermocouples on the sensor membrane and calculates the object temperature using factory set calibration parameters stored in the memory of the chip. The digitized temperature is fully linearized and compensates for ambient temperature. This high level of integration makes the MLX90615 very cost effective compared with previous infrared solutions.
