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Main >> Applications >> Sample problems >> Touch screen

Touchscreen

QuickField simulation example

This is a simplified model of the capacitive touchscreen, where the capacitance of the finger and human body is replaced by the grounded touch area on the touchscreen surface.
Electric potential is applied to the electrodes in the four corners of the conductive sheet. Conductive object with zero potential boundary touches the sheet and the currents in the electrodes depend on the touch position.

Problem Type
Plane-parallel problem of DC Conduction.

Geometry
Touchscreen This is a simplified model of the capacitive touchscreen, where the capacitance of the finger and human body is replaced by the grounded touch area on the touchscreen surface. Finger A B C D 100 mm 200 mm
Screen thickness is 0.1 mm

Given
Electrical conductivity of the touchscreen 100 S/m.
A,B,C,D electrodes voltage +1V.
Finger voltage 0V.

Task
Determine the currents in A,B,C,D electrodes as a function of the touchosition.

Solution
Different touch positions are simulated by separate models. Creation of the new problems, geometry model modification and results measurements are automated with LabelMover.

Results
Electric field distribution in touch screen.
Touchscreen

Due to symmetry you can use a single chart to measure all electrodes currents. Origin x=0, y=0 correspons to the center of the touch screen.