US Patent 11520406 Bipolar projected haptics with balanced loading

An indirect haptic device includes a substrate having a top surface and a bottom surface, and a plurality of haptic electrodes and a plurality of island electrodes arranged on the top surface. The device further includes a plurality of transmit electrodes and a plurality of receive electrodes arranged on the bottom surface, a position sensor, and a friction modulator. The device further includes a control device configured to apply bipolar electrical signals to the plurality of transmit electrodes to detect touch locations of a user's appendage and to modulate the friction between the user's appendage and the touch surface. Each of the plurality of haptic electrodes are substantially aligned with and capacitively coupled to a corresponding two of the plurality of transmit electrodes.