Capacitive touch screen with noise suppression

Abstract

A capacitive touch sensor wherein the touch sensitive panel has drive electrodes arranged on the lower side of a substrate and sense electrodes arranged on the upper side. The drive electrodes are shaped and dimensioned to substantially entirely cover the touch sensitive area with individual drive electrodes being separated from each other by small gaps, the gaps being so small as to be practically invisible. The near blanket coverage by the drive electrodes also serves to screen out interference from noise sources below the drive electrode layer, such as drive signals for an underlying display, thereby suppressing noise pick-up by the sense electrodes that are positioned above the drive electrodes.

What is claimed is: 
     
         1 . A mobile electronic device comprising:
 a housing;   a touch-sensitive display comprising a plurality of layers, the plurality of layers comprising:
 a two-dimensional array of pixels configured to produce an image; 
 a substantially transparent cover layer; 
 a first electrode layer comprising a plurality of first conductive electrodes, wherein the plurality of first conductive electrodes comprises indium tin oxide and is substantially transparent and runs along a first direction; 
 a second electrode layer comprising a plurality of second conductive electrodes, wherein the plurality of second conductive electrodes comprises indium tin oxide and is substantially transparent and runs along a second direction, the second direction transverse to the first direction, wherein the second electrode layer further comprises a first plurality of isolated conductive elements disposed between at least a subset of the plurality of second conductive electrodes; and 
 a substrate situated between the first electrode layer and the second electrode layer; 
   one or more processors comprising a voltage driver and configured to apply drive signals to at least a subset of the plurality of first conductive electrodes and to measure sense signals received from the plurality of second conductive electrodes;
 the one or more processors further configured to calculate information about a touch input to the touch-sensitive display from an analysis of the sense signals received from at least one of the plurality of second conductive electrodes obtained by applying drive signals to at least one of the plurality of first conductive electrodes, wherein the analysis comprises measuring the capacitance at one or more nodes; 
 the one or more processors further configured to communicate information about the touch input to one or more components of the mobile electronic device; and 
   a first plurality of tracks connecting the first conductive electrodes to the one or more processors and a second plurality of tracks connecting the second conductive electrodes to the one or more processors;
 wherein the first plurality of tracks and second plurality of tracks are routed to the one or more processors at the periphery of the plurality of first conductive electrodes and plurality of second conductive electrodes. 
   
     
     
         2 . The mobile electronic device of  claim 1 , wherein the plurality of second conductive electrodes is disposed on a first surface of the substrate. 
     
     
         3 . The mobile electronic device of  claim 2 , wherein the second direction is perpendicular to the first direction. 
     
     
         4 . The mobile electronic device of  claim 3 , wherein the information about the touch input comprises a location of the touch input. 
     
     
         5 . The mobile electronic device of  claim 3 , wherein the information about the touch input comprises a magnitude of the touch input. 
     
     
         6 . The mobile electronic device of  claim 4 , wherein the one or more processors is configured to sequentially apply drive signals to at least a subset of the plurality of first conductive electrodes. 
     
     
         7 . The mobile electronic device of  claim 6 , wherein the first plurality of isolated conductive elements is disposed between two adjacent second conductive electrodes. 
     
     
         8 . The mobile electronic device of  claim 6 , wherein the plurality of first conductive electrodes is substantially filling the entirety of the touch-sensitive display. 
     
     
         9 . The mobile electronic device of  claim 8 , wherein the plurality of second conductive electrodes and the first plurality of isolated conductive elements are substantially area filling within the touch-sensitive display relative to the plurality of second conductive electrodes. 
     
     
         10 . The mobile electronic device of  claim 9 , wherein the two-dimensional array of pixels comprises organic light emitting diodes. 
     
     
         11 . The mobile electronic device of  claim 9 , wherein at least one of the outermost first conductive electrodes is about half the width of the other first conductive electrodes. 
     
     
         12 . The mobile electronic device of  claim 9 , wherein the plurality of first conductive electrodes is disposed on a second surface of the substrate. 
     
     
         13 . The mobile electronic device of  claim 9 , wherein the plurality of first conductive electrodes is disposed on a different substrate. 
     
     
         14 . The mobile electronic device of  claim 9 , wherein the first plurality of isolated conductive elements is disposed on the first surface of the substrate. 
     
     
         15 . The mobile electronic device of  claim 9 , wherein the first electrode layer further comprises a second plurality of isolated conductive elements disposed between at least a subset of the plurality of first conductive electrodes. 
     
     
         16 . The mobile electronic device of  claim 14 , wherein the first plurality of isolated conductive elements is square shaped. 
     
     
         17 . A mobile electronic device comprising:
 a housing;   a touch-sensitive display comprising a plurality of layers, the plurality of layers comprising:
 a two-dimensional array of pixels configured to produce an image; 
 a substantially transparent cover layer; 
 a first electrode layer comprising a plurality of first conductive electrodes, wherein the plurality of first conductive electrodes comprises indium tin oxide and is substantially transparent and runs along a first direction; 
 a second electrode layer comprising a plurality of second conductive electrodes, wherein the plurality of second conductive electrodes comprises indium tin oxide and is substantially transparent and runs along a second direction, the second direction transverse to the first direction, wherein the second electrode layer further comprises a first plurality of isolated conductive elements disposed between at least a subset of the plurality of second conductive electrodes; and 
 an isolation layer situated between the first electrode layer and the second electrode layer; 
   one or more processors comprising a voltage driver and configured to apply drive signals to at least a subset of the plurality of first conductive electrodes and to measure sense signals received from the plurality of second conductive electrodes;
 the one or more processors further configured to calculate information about a touch input to the touch-sensitive display from an analysis of the sense signals received from at least one of the plurality of second conductive electrodes obtained by applying drive signals to at least one of the plurality of first conductive electrodes, wherein the analysis comprises measuring the capacitance at one or more nodes; 
 the one or more processors further configured to communicate information about the touch input to one or more components of the mobile electronic device; and 
   a first plurality of tracks connecting the first conductive electrodes to the one or more processors and a second plurality of tracks connecting the second conductive electrodes to the one or more processors;
 wherein the first plurality of tracks and second plurality of tracks are routed to the one or more processors at the periphery of the plurality of first conductive electrodes and plurality of second conductive electrodes. 
   
     
     
         18 . The mobile electronic device of  claim 17 , wherein the second direction is perpendicular to the first direction. 
     
     
         19 . The mobile electronic device of  claim 18 , wherein the information about the touch input comprises a location of the touch input. 
     
     
         20 . The mobile electronic device of  claim 18 , wherein the information about the touch input comprises a magnitude of the touch input. 
     
     
         21 . The mobile electronic device of  claim 19 , wherein the one or more processors is configured to sequentially apply drive signals to at least a subset of the plurality of first conductive electrodes. 
     
     
         22 . The mobile electronic device of  claim 21 , wherein the plurality of first conductive electrodes is substantially filling the entirety of the touch-sensitive display. 
     
     
         23 . The mobile electronic device of  claim 22 , wherein the plurality of second conductive electrodes and the first plurality of isolated conductive elements are substantially area filling within the touch-sensitive display relative to the plurality of second conductive electrodes. 
     
     
         24 . The mobile electronic device of  claim 23 , wherein the two-dimensional array of pixels comprises organic light emitting diodes. 
     
     
         25 . The mobile electronic device of  claim 23 , wherein at least one of the outermost first conductive electrodes is about half the width of the other first conductive electrodes. 
     
     
         26 . The mobile electronic device of  claim 21 , wherein the first plurality of isolated conductive elements is disposed between two adjacent second conductive electrodes. 
     
     
         27 . An apparatus comprising:
 a housing;   a touch-sensitive display comprising a plurality of layers, the plurality of layers comprising:
 a two-dimensional array of pixels configured to produce an image; 
 a substantially transparent cover layer; 
 a first electrode layer comprising a plurality of first conductive electrodes, wherein the plurality of first conductive electrodes comprises indium tin oxide and is substantially transparent and runs along a first direction; 
 a second electrode layer comprising a plurality of second conductive electrodes, wherein the plurality of second conductive electrodes comprises indium tin oxide and is substantially transparent and runs along a second direction, the second direction perpendicular to the first direction, wherein the second electrode layer further comprises a first plurality of isolated conductive elements disposed between at least a subset of the plurality of second conductive electrodes; and 
 a substrate situated between the first electrode layer and the second electrode layer, wherein the plurality of second conductive electrodes is disposed on a first surface of the substrate; 
   one or more processors comprising a voltage driver and configured to sequentially apply drive signals to at least a subset of the plurality of first conductive electrodes and to measure sense signals received from the plurality of second conductive electrodes;
 the one or more processors further configured to calculate information about a touch input to the touch-sensitive display from an analysis of the sense signals received from at least one of the plurality of second conductive electrodes obtained by applying drive signals to at least one of the plurality of first conductive electrodes, wherein the analysis comprises measuring the capacitance at one or more nodes, wherein the information about the touch input comprises a location of the touch input; 
 the one or more processors further configured to output information about the touch input; and 
   a first plurality of tracks connecting the first conductive electrodes to the one or more processors and a second plurality of tracks connecting the second conductive electrodes to the one or more processors;
 wherein the first plurality of tracks and second plurality of tracks are routed to the one or more processors at the periphery of the plurality of first conductive electrodes and plurality of second conductive electrodes. 
   
     
     
         28 . The apparatus of  claim 27 , wherein the first plurality of isolated conductive elements is disposed between two adjacent second conductive electrodes. 
     
     
         29 . The apparatus of  claim 27 , wherein the plurality of second conductive electrodes and the first plurality of isolated conductive elements are substantially area filling within the touch-sensitive display relative to the plurality of second conductive electrodes. 
     
     
         30 . The apparatus of  claim 29 , wherein the plurality of first conductive electrodes is substantially filling the entirety of the touch-sensitive display.