Title :
Interdigitated humidity sensors for a portable clinical microsystem
Author :
Laville, Céline ; Pellet, Claude
Author_Institution :
Lab. IXL, Bordeaux I Univ., Talence, France
Abstract :
This paper presents and compares two capacitive humidity sensors with interdigitated electrodes for a portable clinical application. A polyimide-sensitive layer covers the first structures and the optimized ones include a benzocyclobutene-sensitive layer and a heating resistor. Humidity measurements results are presented, in particular sensors response time in absorption, which are very small (inferior to 500 ms). Next, mechanisms of absorption and adsorption in a polymer layer are described and the two structures are compared. Suitability of optimized sensors for our application is discussed: new structures allow us to increase sensitivity and decrease response time. When the structure is maintained at 40°C by its heater, the response time is 200 ms and the total desorption time is 11 s.
Keywords :
biomedical electrodes; biomedical transducers; capacitive sensors; humidity sensors; resistors; 11 s; 200 ms; 40 C; 500 ms; benzocyclobutene-sensitive layer; capacitive humidity sensors; dynamic measurements; heating resistor; interdigitated humidity sensors; medical microsystem; polymer layer; portable clinical microsystem; response time decrease; static measurements; Absorption; Capacitance measurement; Capacitive sensors; Delay; Educational institutions; Electrodes; Humidity measurement; Laboratories; Permittivity measurement; Polymers; Adsorption; Aluminum; Biosensing Techniques; Electric Capacitance; Equipment Design; Equipment Failure; Heating; Humidity; Microelectrodes; Miniaturization; Monitoring, Physiologic; Resins, Synthetic; Sensitivity and Specificity;
Journal_Title :
Biomedical Engineering, IEEE Transactions on
DOI :
10.1109/TBME.2002.802052
