The SHT3x membrane is a PTFE foil, dedicated to protect the sensor opening from water and dust
according to IP67. It will thus allow for sensor use under harsh environmental conditions, where spray water and high exposure to dust is challenging for accurate sensor performance. The membrane cover is attached to the sensor package by a double faced adhesive tape, which is designed to stay on the package over the whole sensor life time. Due to the minimum enclosed air
volume, the response time of the RH signal is the same as the value achieved by the uncovered sensor.
Sensirion holds an exclusive license for several patents for employing an on-package filter membrane on a humidity sensorl.