Touch input device

Abstract

A touch sensor input device includes a first and second array of electrodes, the electrodes in the first array being orthogonal to the electrodes in the second array. A capacitor sensing arrangement senses an electrode capacitance signal which varies in the presence of a touch input. The capacitance signals for groups of electrodes in each array are combined in order to derive respective individual sense signals. This arrangement has electrodes with a finer resolution than the sensing resolution, and this gives improved ability to sense accurately the position of the touch input.

1 . A display device with touch sensor input, the display device comprising an array display pixels or an array of display sub-pixels with groups of sub-pixels together defining respective display pixels, the device comprising:
 a display layer; and   a touch sensor input device over the display layer for enabling a touch input to the device, wherein the touch sensor input device comprises:
 a first and second array of electrodes, the electrodes in the first array being orthogonal to the electrodes in the second array; and 
 a capacitor sensing arrangement for sensing an electrode capacitance signal which varies in the presence of the touch input, 
 wherein the electrode capacitance signals for groups of the electrodes in each array are combined in order to derive respective individual sense signals, 
   wherein the pitch of the electrodes of the first and second array is the same as a pixel or sub-pixel pitch of the display device.   
     
     
         2 . The device as claimed in  claim 1 , wherein some electrodes of one or both of the first and second arrays of electrodes function as dummy electrodes which are not used in any of the groups of electrodes and thereby are not used to derive any individual sense signals. 
     
     
         3 . The device as claimed in  claim 1 , wherein each group of electrodes comprises an adjacent group of electrodes. 
     
     
         4 . The device as claimed in  claim 1 , wherein each group of electrodes comprises a group of electrodes which are not an adjacent block of electrodes. 
     
     
         5 . The device as claimed in  claim 4 , wherein the different individual sense signals are each derived from different electrodes, so that no electrode is used to derive multiple different sense signals. 
     
     
         6 . The device as claimed in  claim 1 , wherein the electrodes of a group are physically electrically connected together. 
     
     
         7 . The device as claimed in  claim 1 , wherein not all electrodes of a group are physically electrically connected together, and the combination is at least in part implemented by signal processing. 
     
     
         8 . The device as claimed in  claim 1 , wherein the arrays of electrodes each comprise straight electrode lines, with enlarged portions along the lines, with a spacing between the enlarged portions corresponding to the pitch between the electrode lines of other array, the enlarged portions in one array having a different size to the enlarged portions in the other array. 
     
     
         9 . The device as claimed in  claim 8 , wherein the enlarged portions are diamond shapes. 
     
     
         10 . The device as claimed in  claim 1 , wherein the two electrode arrays have the same pitch. 
     
     
         11 . The device as claimed in  claim 1 , further comprising a colour filter arrangement. 
     
     
         12 . The device as claimed in any preceding claim, wherein the touch sensor input device comprises a glass substrate between the first and second arrays of electrodes, and an anti-scratch coating over the second electrode array, which is on the opposite side of the glass substrate to the display layer. 
     
     
         13 . The device as claimed in  claim 1 , wherein the display layer comprises a liquid crystal layer.