Capacitive touch button with guard

Abstract

An apparatus such as a set-top box, includes at least one capacitive touch button with a guard feature that provides, the ability to detect and reject false touches. According to an exemplary embodiment, the apparatus includes a first conductive element that is capacitively isolated from ground, and a second conductive element that is capacitively isolated from ground and located adjacent to the first conductive element. A first sensor is coupled to the first conductive element and measures a change in capacitance between the first conductive element and ground due to a change in physical environment. A second sensor is coupled to the second conductive element and measures a change in capacitance between the second conductive element and ground due to the change in physical environment. A controller is coupled to the first sensor and the second sensor and determines a difference between the measured changes in capacitance.

1 - 21 . (canceled) 
     
     
         22 . An apparatus, comprising:
 a first conductive element, the first conductive element electrically isolated from ground;   a second conductive element, the second conductive element electrically isolated from ground and located adjacent to the first conductive element;   a first sensor coupled to the first conductive element, the first sensor measuring a change in a first sensor output value, the change in the first sensor output value being representative of a change in an electrical characteristic between the first conductive element and ground due to a change in physical environment;   a second sensor coupled to the second conductive element, the second sensor measuring a change in a second sensor output value, the change in the second sensor output value being representative of a change in an electrical characteristic between the second conductive element and ground due to the change in physical environment; and   a controller coupled to the first sensor and the second sensor, the controller determining a difference between the measured changes in sensor output value of the first sensor and sensor output value of the second sensor,   wherein if the determined difference is equal to or exceeds a value, the controller determines that the change in physical environment represents a valid user input to the apparatus.   
     
     
         23 . The apparatus of  claim 22 , wherein if the determined difference is less than the value, the controller determines that the change in physical environment does not represent a valid user input to the apparatus. 
     
     
         24 . The apparatus of  claim 22 , wherein the first conductive element is formed from a plurality of conductive elements and the second conductive element is formed from a different plurality of conductive elements adjacent to the first conductive element. 
     
     
         25 . The apparatus of  claim 22 , wherein:
 the first conductive element represents a first portion of a touch button; and   the second conductive element represents a second portion of the touch button.   
     
     
         26 . The apparatus of  claim 25 , wherein the touch button is formed as part of a touch panel. 
     
     
         27 . The apparatus of  claim 22 , wherein the first conductive element and second conductive element are capacitively isolated from ground, the change in the first sensor output value is representative of a change in capacitance between the first conductive element and ground, and the change in the second sensor output value is representative of a change in capacitance between the second conductive element and ground. 
     
     
         28 . The apparatus of  claim 22 , wherein:
 the first conductive element is circular; and   the second conductive element is concentric with substantially all of the first conductive element.   
     
     
         29 . The apparatus of  claim 22 , wherein the value is twenty percent of the value of the measured change in sensor output value of the second sensor. 
     
     
         30 . The apparatus of  claim 22 , wherein the apparatus is a portable device. 
     
     
         31 . A method, comprising:
 measuring a change in a first sensor output value, the change in the first sensor output value being representative of a change in an electrical value between a first conductive element and ground due to a change in physical environment;   measuring a change in a second sensor output value, the change in the second sensor output value being representative of a change in an electrical value between a second conductive element and ground due to the change in physical environment, wherein the second conductive element is located adjacent to the first conductive element;   determining a difference between the measured changes in the first sensor output value and the second sensor output value; and   determining that the change in physical environment represents a valid user input to an apparatus if the determined difference is equal to or exceeds a value.   
     
     
         32 . The method of  claim 31 , further comprising determining that the change in physical environment does not represent a valid user input to the apparatus if the determined difference is less than the value. 
     
     
         33 . The method of  claim 31 , wherein the first conductive element is formed from a plurality of conductive elements and the second conductive element is formed from a different plurality of conductive elements adjacent to the first conductive element. 
     
     
         34 . The method of  claim 33 , wherein:
 the first conductive element represents a first portion of a capacitive touch button of an apparatus; and   the second conductive element represents a second portion of the capacitive touch button.   
     
     
         35 . The method of  claim 34 , wherein the touch button is formed as part of a touch panel. 
     
     
         36 . The method of  claim 31 , wherein the first conductive element and second conductive element are capacitively isolated from ground, the change in the first sensor output value is representative of a change in capacitance between the first conductive element and ground, and the change in the second sensor output value is representative of a change in capacitance between the second conductive element and ground. 
     
     
         37 . The method of  claim 31 , wherein:
 the first conductive element is circular; and   the second conductive element is concentric with substantially all of the first conductive means.   
     
     
         38 . The method of  claim 31 , wherein the value is twenty percent of the value of the measured change in the second sensor output value. 
     
     
         39 . The method of  claim 31 , wherein the apparatus is a portable device. 
     
     
         40 . An apparatus, comprising:
 at least one first conductive element, the at least one first conductive element electrically isolated from ground, the at least one first conductive element forming a touch button region on a touch panel;   at least one second conductive element, the at least one second conductive element electrically isolated from ground and located adjacent to the at least one first conductive element;   at least one first sensor coupled to the at least one first conductive element, the at least one first sensor each measuring a change in a first sensor output value, the change in the first sensor output value being representative of a change in an electrical characteristic between the at least one first conductive element and ground due to a change in physical environment;   at least one second sensor coupled to the at least one second conductive element, the at least one second sensor each measuring a change in a second sensor output value, the change in the second sensor output value being representative of a change in an electrical characteristic between the at least one second conductive element and ground due to the change in physical environment; and   a controller coupled to the at least one first sensor and the at least one second sensor, the controller determining a difference between the measured changes in sensor output value of the first sensor and sensor output value of the second sensor,   wherein if the determined difference is equal to or exceeds a value, the controller determines that the change in physical environment represents a valid user input to the apparatus.   
     
     
         41 . The apparatus of  claim 40 , wherein if the determined difference is less than the value, the controller determines that the change in physical environment does not represent a valid user input to the apparatus. 
     
     
         42 . The apparatus of  claim 40 , wherein the touch button region includes at least a button for powering the apparatus. 
     
     
         43 . The apparatus of  claim 40 , wherein the at least one first conductive element and at least one second conductive element are capacitively isolated from ground, the change in the at least one first sensor output value is representative of a change in capacitance between the at least one first conductive element and ground, and the change in the at least one second sensor output value is representative of a change in capacitance between the at least one second conductive element and ground. 
     
     
         44 . The apparatus of  claim 40 , wherein the apparatus is a portable device.