US Patent 9921649 Electrostatic haptic based user input elements

A user input element includes a first part having a first capacitive surface, a second part having a second capacitive surface configured to be movable relative to the first capacitive surface, and an insulator positioned in between the first capacitive surface and the second capacitive surface so that a haptic effect is generated when the second capacitive surface is moved relative to the first capacitive surface from a first position to a second position. The user input element may be part of a haptic feedback interface system configured to provide haptic effects to a user operating the system.