Finger/stylus touch pad

Abstract

A touch pad module to implement user input functions to an electronic device is disclosed. The touch pad module includes a sensor layer which, when used in conjunction with an insulative layer and contiguous conductive layer enable the touch pad module to sense both finger and stylus input data to the electronic device.

1 . A capacitive touch pad module comprising:
 a first set of conductive lines;   a second set of conductive lines insulated from the first set of conductive lines;   an insulating layer disposed over the first and second sets of conductive lines;   a conductive layer placed over the insulating layer, the conductive layer configured such that it would spread out a ground image of a grounded conductive stylus in contact with the conductive layer.   
   
   
       2 . The capacitive touch pad module of  claim 1  wherein the touch pad module further includes a means for distinguishing a characteristic of the conductive object. 
   
   
       3 . The capacitive touch pad module of  claim 2 , wherein the means for distinguishing a characteristic of the conductive object distinguishes between stylus and finger. 
   
   
       4 . The capacitive touch pad module of  claim 1  wherein the conductive layer comprises a conductive material disposed in a plastic carrier. 
   
   
       5 . The capacitive touch pad module of  claim 1  wherein the first set of conductive lines runs in a first direction, wherein the second set of conductive lines runs in a second direction generally perpendicular to the first direction, and wherein the first set of conductive lines and the second set of conductive lines form an electrode grid. 
   
   
       6 . The capacitive touch pad module of  claim 1  wherein a first subset of the first set of conductive lines is configured to have applied to it an oscillating potential of a given frequency and a first phase, and wherein a second subset of the first set of conductive lines is configured to have applied to it an oscillating potential of the given frequency and a second phase, wherein the second phase is opposite to the first phase. 
   
   
       7 . The capacitive touch pad module of  claim 1  wherein the first set of conductive lines comprise printed circuit board traces and the second set of conductive lines comprise printed circuit board traces. 
   
   
       8 . The capacitive touch pad module of  claim 1 , wherein the first set of conductive lines is transparent, the second set of conductive lines is transparent, the insulating layer is transparent, and the conductive layer is transparent. 
   
   
       9 . The capacitive touch pad module of  claim 1 , wherein the touch pad module is transparent, further comprising:
 a display screen under the first set of conductive lines, the second set of conductive lines, the insulating layer, and the conductive layer.   
   
   
       10 . A touch pad module comprising:
 a surface;   a first set of conductive lines located below the surface;   a second set of conductive lines insulated from the first set of conductive lines and located below the surface, wherein the first and second set of conductive lines are configured to detect changes in capacitance resulting from a stylus in contact with the surface;   an insulating layer disposed over the first and second sets of conductive lines; and   a conductive layer placed over the insulating layer, the conductive layer configured such that it would spread a ground image of a grounded object in contact with the conductive layer.   
   
   
       11 . The touch pad module of  claim 10  wherein the touch pad module further includes a means for distinguishing between stylus contact and finger contact. 
   
   
       12 . The touch pad module of  claim 10  wherein the conductive layer comprises a conductive material disposed in a plastic carrier. 
   
   
       13 . The touch pad module of  claim 10  wherein the first set of conductive lines and the second set of conductive lines form an electrode grid. 
   
   
       14 . The touch pad module of  claim 10  wherein a first subset of the first set of conductive lines is configured to have applied to it an oscillating potential of a given frequency and a first phase, and wherein a second subset of the first set of conductive lines is configured to have applied to it an oscillating potential of the given frequency and a second phase, wherein the second phase is opposite to the first phase. 
   
   
       15 . The touch pad module of  claim 10  wherein the touch pad module is transparent, further comprising:
 a display screen under the first set of conductive lines, the second set of conductive lines, the insulating layer, and the conductive layer.   
   
   
       16 . A capacitive touch pad module comprising:
 a surface;   a set of conductive lines disposed under the surface;   an insulating material disposed over the set of conductive lines;   a conductive layer placed over the insulating layer, wherein the set of conductive lines, the insulating layer, and the conductive layer are configured to create a detectable capacitance change when a user places a stylus in contact with the surface, the detectable capacitance change determined in part by the conductive layer, and wherein the conductive layer is configured to create an image of the conductive object to thereby make the detectable capacitance change greater than without the conductive layer.   
   
   
       17 . The capacitive touch pad module of  claim 16  wherein the set of conductive lines, the insulating layer, and the conductive layer are configured to distinguish between stylus and finger. 
   
   
       18 . The capacitive touch pad module of  claim 16  wherein the set of conductive lines form an electrode grid. 
   
   
       19 . The capacitive touch pad module of  claim 16  wherein a first subset of the set of conductive lines is configured to have applied to it an oscillating potential of a given frequency and a first phase, and wherein a second subset of the set of conductive lines is configured to have applied to it an oscillating potential of the given frequency and a second phase, wherein the second phase is opposite to the first phase. 
   
   
       20 . The capacitive touch pad module of  claim 16  wherein the touch pad module is transparent, and further comprising:
 a display screen under the first set of conductive lines, the second set of conductive lines, the insulating layer, and the conductive layer.