Method and apparatus for controlling generation of electrostatic friction effects for a plurality of electrodes

Abstract

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.

1 - 18 . (canceled) 
     
     
         19 . An interface device configured to provide an electrostatic friction (ESF) effect, the interface device comprising:
 a signal generating circuit configured to generate a first drive signal at an output of the signal generating circuit;   a first electrode disposed at a surface of the interface device and permanently electrically connected to a source of ground potential;   a second set of electrodes disposed at the surface of the interface device, wherein the first electrode is not part of the second set of electrodes;   a plurality of gating elements, wherein each gating element of the plurality of gating elements comprises at least one switch and is configured to switch between (a) electronically connecting a respective electrode of the second set of electrodes to the output of the signal generating circuit and (b) electrically connecting the respective electrode to the source of ground potential or leaving the respective electrode in an electrically floating state;   a control circuit configured
 to select one or more electrodes of the second set of electrodes to output the ESF effect with the first drive signal, 
 to control the plurality of gating elements to electrically connect the one or more electrodes that have been selected to the output of the signal generating circuit, and 
 to control the plurality of gating elements to either: electrically connect all unselected electrodes of the second set of electrodes to the source of ground potential, or leave all unselected electrodes of the second set of electrodes in the electrically floating state. 
   
     
     
         20 . The interface device of  claim 19 , wherein the signal generating circuit comprises a signal processor and an amplifier, wherein the signal processor is configured to generate an initial drive signal, and the amplifier is configured to amplify the initial drive signal to generate the first drive signal, and wherein each gating element of the plurality of gating elements is electrically connected to an output of the amplifier. 
     
     
         21 . The interface device of  claim 20 , wherein the amplifier is configured to generate the first drive signal with an amplitude of at least 1 kV. 
     
     
         22 . The interface device of  claim 21 , wherein the signal generating circuit is configured to generate the first drive signal as a pulse with the amplitude of at least 1 kV. 
     
     
         23 . The interface device of  claim 21 , wherein the amplifier is the only amplifier of the signal generating circuit for amplifying any signal from the signal processor. 
     
     
         24 . The interface device of  claim 23 , wherein each electrode of the second set of electrodes is an insulated electrode. 
     
     
         25 . The interface device of  claim 24 , wherein the first electrode is an exposed electrode. 
     
     
         26 . The interface device of  claim 20 , wherein the at least one switch of a respective gating element of the plurality of gating elements is a relay switch or a transistor. 
     
     
         27 . The interface device of  claim 19 , wherein the control circuit is configured
 to select only one electrode of the second set of electrodes to generate the ESF effect with the first drive signal,   to control the plurality of gating elements to electrically connect only the one electrode that is selected to the output of the signal generating circuit, and   to control the plurality of gating elements to electrically connect all unselected electrodes of the second set of electrodes to the source of ground potential.   
     
     
         28 . The interface device of  claim 19 , wherein the interface device is a wearable device having a band, wherein the surface of the interface device includes a surface of the band, and wherein the plurality of electrodes are disposed at the surface of the band. 
     
     
         29 . The interface device of  claim 28 , wherein each electrode of the second set of electrodes is shaped as a strip. 
     
     
         30 . The interface device of  claim 19 , wherein the second set of electrodes are arranged as a two-dimensional array. 
     
     
         31 . The interface device of  claim 19 , wherein the control circuit is configured to determine a spatial relationship between a location of an object or event and a location of the interface device,
 wherein the control circuit is configured to select the one or more electrodes of the second set of electrodes based on the spatial relationship between the location of the object or event and the location of the interface device.   
     
     
         32 . The interface device of  claim 19 , wherein the control circuit is configured to determine a temporal relationship between a time of an event and a current time,
 wherein the control circuit is configured to select the one or more electrodes of the second set of electrodes based on the temporal relationship between the time of the event and the current time.   
     
     
         33 . The interface device of  claim 19 , wherein each gating element of the plurality of gating elements comprises a first switch and a second switch, wherein the first switch is configured to switch between electrically connecting a respective electrode of the second set of electrodes to the output of the signal generating circuit and leaving the respective electrode in the electrically floating state, and wherein the second switch is configured to switch between electrically connecting the respective electrode to the source of ground potential and leaving the respective electrode in the electrically floating state. 
     
     
         34 . The interface device of  claim 19 , wherein the control circuit is configured to select the one or more electrodes from among a subset of the second set of electrodes, the subset of electrodes receiving user contact, such that some electrodes of the second set of electrodes receiving user contact are not selected to generate a respective ESF effect with the first drive signal. 
     
     
         35 . The interface device of  claim 19 , wherein the interface device is a mobile device, and the second set of electrodes are disposed on a back surface of the mobile device. 
     
     
         36 . The interface device of  claim 35 , wherein each electrode of the second set of electrodes is shaped as a circle or as a square.