Touch Sensor Device and Method

Abstract

A common capacitive touch sensor may have a two dimensional array of transparent conductive strips going from edge to edge on a substrate layer or sheet of a touch sensor. According to some aspects, there is provided a capacitive touch sensor device including a substrate layer and a plurality of resonant circuits. Each resonant circuit includes an electrode, and each resonant circuit has a respective resonance frequency that is unique within the plurality of resonant circuits. The electrodes of the resonant circuits are distributed on the substrate layer. A controller for a touch sensor is also provided that includes a signal generator to drive at least one plurality of resonant circuits, where each resonant circuit has a respective resonance frequency. The signal generator is tunable to generate input signals at each of the resonance frequencies. The controller also includes a detector.

1 . A capacitive touch sensor device comprising:
 a substrate layer; and   a plurality of resonant circuits, each comprising at least one respective electrode, the electrodes of the plurality of resonant circuits being distributed on the substrate layer, and   each of the plurality of resonant circuits having a respective resonance frequency that is unique within the plurality of resonant circuits.   
     
     
         2 . The capacitive touch sensor device of  claim 1 , further comprising, a respective circuit input and a respective circuit output, the plurality of resonant circuits being collectively connected to the respective circuit input and collectively connected to the respective circuit output. 
     
     
         3 . The capacitive touch sensor device of  claim 1 , wherein, for each said resonant circuit, the at least one respective electrode comprises at least one electrode strip. 
     
     
         4 . The capacitive touch sensor device of  claim 3 , wherein the at least one electrode strip comprises a first electrode strip and a second electrode strip parallel to and spaced apart from the first electrode strip. 
     
     
         5 . The capacitive touch sensor device of  claim 1 , further comprising a signal generator that selectively generates signals at each of the resonance frequencies to drive the plurality of resonant circuits. 
     
     
         6 . The capacitive touch sensor device of  claim 5 , further comprising a detector that measures output of the plurality of resonant circuits. 
     
     
         7 . The capacitive touch sensor device of  claim 6 , further comprising a processor that controls the tunable signal generator and the detector to scan the plurality of resonant circuits, said scanning comprising sequentially generating the signals at each of the resonant frequencies, and measuring the output of the plurality of resonant circuits. 
     
     
         8 . The capacitive touch sensor device of  claim 6 , further comprising a respective circuit input and a respective circuit output, the plurality of resonant circuits being collectively connected to the respective circuit input and collectively connected to the respective circuit output,
 wherein the touch sensor device comprises a controller that comprises the signal generator, the detector and the processor, the controller being connected to said circuit input to drive the plurality of resonant circuits with the signals, and the controller being connected to said circuit output for the detector to measure the output of the plurality of resonant circuits.   
     
     
         9 . The capacitive touch sensor device of  claim 1 , further comprising at least one additional plurality of resonant circuits, each resonant circuit of the at least one additional plurality of resonant circuits comprising at least one respective electrode, the electrodes of the at least one additional plurality of resonant circuits being distributed on the substrate layer, wherein
 for each said additional plurality of resonant circuits, each said resonant circuit of the additional plurality has a respective resonance frequency that is unique within the additional plurality of resonant circuits.   
     
     
         10 . The capacitive touch sensor device of  claim 9 , further comprising:
 a signal generator that selectively generates signals at each of the resonance frequencies of the pluralities of resonant circuits;   a detector that measures output of each of the pluralities of resonant circuits; and   switching circuitry connected to the signal generator for selectively driving the pluralities of resonant circuits with the signals.   
     
     
         11 . The capacitive touch sensor device of  claim 10 , further comprising a processor that controls the signal generator, the detector and the switching circuity to scan each of the pluralities of resonant circuits, said scanning comprising, for each plurality of resonant circuits, sequentially generating the signals at each of the respective resonant frequencies, and measuring the output of the plurality of resonant circuits. 
     
     
         12 . The capacitive touch sensor device of  claim 9 , wherein at least one of the resonant frequencies for at least two of the pluralities of resonant circuits are substantially similar. 
     
     
         13 . The capacitive touch sensor device of  claim 6 , wherein the detector comprises at least one of: an analog to digital converter (ADC); and a comparator. 
     
     
         14 . The capacitive touch sensor device of  claim 10 , wherein the detector comprises at least one of: an analog to digital converter (ADC); and a comparator. 
     
     
         15 . The capacitive touch sensor device of  claim 1 , wherein each resonant circuit comprises a respective capacitor having a respective capacitance value and a respective inductor having a respective inductance value, a combination of the respective capacitance value and the respective inductance value being unique within the plurality of resonant circuits. 
     
     
         16 . The capacitive touch sensor device of  claim 15 , wherein the inductors of the plurality of resonant circuits are planar inductors, each planar inductor comprising at least one respective conductor layer deposited on the substrate layer. 
     
     
         17 . The capacitive touch sensor device of  claim 16 , wherein, for each said planar inductor, the at least one respective conductor layer comprises at least one spiral shaped inductor coil. 
     
     
         18 . The capacitive touch sensor device of  claim 1 , wherein the resonant frequencies of the at least one plurality of resonant circuits are in the Radio Frequency (RF) range, and the signal generator is a tunable RF signal generator. 
     
     
         19 . A method for a capacitive touch sensor comprising at least one plurality of resonant circuits, each plurality of resonant circuits having a respective plurality of resonance frequencies, the method comprising:
 for each said at least one plurality of resonant circuits:   sequentially generating signals at each of the respective plurality of resonance frequencies for driving the plurality of resonant circuits; and   measuring an output of the plurality of resonant circuits.   
     
     
         20 . The method of  claim 19 , wherein said sequentially generating comprises selectively generating signals at each of the respective plurality of resonance frequencies in a cyclic or random hopping pattern. 
     
     
         21 . A controller for a capacitive touch sensor comprising at least one plurality of resonant circuits, each plurality of resonant circuits having a respective plurality of resonance frequencies, the controller comprising:
 a signal generator to drive the at least one plurality of resonant circuits, the signal generator being tunable to selectively generate signals at each of the resonance frequencies for driving the at least one plurality of resonant circuits; and   a detector to measure output the at least one plurality of resonant circuits.   
     
     
         22 . The controller of  claim 21 , further comprising a processor that controls the signal generator and the detector to scan the at least one plurality of resonant circuits,
 said scanning comprising, for each said plurality of resonant circuits, sequentially generating the signals at each of the resonant frequencies, and measuring the output of the plurality of resonant circuits.   
     
     
         23 . The controller of  claim 21 , further comprising switching circuitry connected to the signal generator for selectively driving the at least one plurality of resonant circuits with the signals. 
     
     
         24 . The controller of  claim 23 , further comprising at least one output, each said at least one output for connecting to a corresponding input of a respective one of the at least one plurality of resonant circuits. 
     
     
         25 . The controller of  claim 21 , wherein the detector comprises at least one of: an analog to digital converter (ADC); and a comparator.