Method and apparatus for controlling generation of electrostatic friction effects for a plurality of electrodes
US Patent 9,928,700, filed January 25, 2017, issued March 27, 2018.download pdf
An interface device configured to provide an electrostatic friction (ESF) effect is disclosed. The interface device comprises a plurality of electrodes disposed at a surface of the interface device. It further comprises a signal generating circuit configured to generate a first drive signal at an output of the signal generating circuit, and comprises a plurality of frequency filter units or delay elements electrically connected to the signal generating circuit and to the plurality of electrodes. The interface device further comprises a control unit configured to use the plurality of frequency filter units or delay elements: (i) to cause only a subset of one or more electrodes of the plurality of electrodes to output one or more respective ESF effects with the first drive signal, or (ii) to cause at least two electrodes to output respective ESF effects with the first drive signal in different respective manners.