Biuletyn Wojskowej Akademii Technicznej (Jun 2022)
Comparative analysis of selected performance parameters of capacitive touch sensors
Abstract
In the article, various types of touch buttons are presented and compared, including standardself-capacitance buttons and Metal over Cap Technology (MoCT) buttons which work through thedeflection of the additional covering conductive layer.Two types of touch buttons have been simulated. Standard self-capacitance buttons have been simulatedusing built-in CapExt software standard capacitive sensors models while for MoCT buttons, a speciallydesigned simulation model has been developed, which has made a simulation of phenomena occurringin the sensors manufactured in this technology possible. Furthermore, two physical models of capacitivebuttons have been designed and constructed. The parameters of both buttons have been tested andcompared with the simulated results. There is a presentation of a specifically designed and constructedtool which allows simulating a touch event with high accuracy and repeatability. Test results of thetouch force required to activate the sensor, created in the MoCT technology, are presented and theresults are compared against the parameters of classic mechanical buttons.The research has shown that MoCT touch sensors have a high resistance to false detection. Theresearch described in the article allows selecting the effective construction materials for MoCT buttons,depending on the required user parameters such as pressing force and construction parameters suchas required panel thickness (strength). A comparative analysis of the empirical data and the results ofsimulations, conducted with commercially available software, allows accelerating the design processof such buttons and introducing appropriate corrections to the simulation results in the process ofdesigning the final device.Keywords: capacitive touch sensor, parallel plate type capacitive pressure sensor, capacitive pressorsensors, sensing performance
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