June 10, 2016
Projected capacitive touchscreens are widely used in several modern devices, such as smartphones and tablets. Projected capacitive touchscreen sensors generally consist of two coplanar electrode grids surrounded by dielectric layers. Their operation is based on the reduction of the mutual capacitance between the electrodes as a finger or generally a conductive object comes close to the touchscreen surface.
Touchscreen simulation tool developed by Fieldscale, Sense, helps touchscreen designers to evaluate several touch sensor designs in terms of their performance for several finger positions. Through parametric analysis Sense allows the optimization of touchscreen sensors by combining electrostatic simulation with controller’s specifications.
The present report demonstrates an example on how Sense can be used for the optimization of touchscreen sensors based on a specific controller. Simulation results clearly show that important amount of material of both electrodes (ITO) and dielectrics (PE) can be saved, without losing compatibility between touch sensor and controller. Besides its reduced cost, the thinner touch sensor results in a higher sensitivity, indicating an also higher signal-to-noise ratio (SNR).