Reduction of noise in touch sensors
First Claim
1. A method for providing a cleaned signal in a capacitive touch sensor, the capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix, the method comprising:
- determining a phase of periodic noise on an input of the capacitive touch sensor;
generating a periodic excitation signal having a phase that is locked to the determined phase of the periodic noise;
applying the periodic excitation signal to an excited conductor in the first array;
while the excitation signal is applied, detecting a response signal on a responding conductor in the second array, and generating, based on the detected response signal, a value indicative of a measured capacitance between the excited conductor and the responding conductor;
accessing a threshold value;
determining whether the response signal corresponds to a touch based on a difference between the value and the threshold value; and
producing a signal reflecting results of the determination of whether the response signal corresponds to a touch.
3 Assignments
0 Petitions
Accused Products
Abstract
Techniques are described for providing a cleaned signal in a capacitive touch sensor. A phase of periodic noise on an input of the capacitive touch sensor is determined, and a periodic excitation signal having a phase that is locked to the determined phase of the periodic noise is generated. The periodic excitation signal is applied to an excited conductor in a first array of the touch sensor. While the excitation signal is applied, a response signal on a responding conductor in a second array of the touch sensor is detected, and, based on the detected response signal, a value indicative of a measured capacitance between the excited conductor and the responding conductor is generated. A threshold value is accessed, and a determination is made whether the response signal corresponds to a touch based on a difference between the value and the threshold value.
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Citations
85 Claims
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1. A method for providing a cleaned signal in a capacitive touch sensor, the capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix, the method comprising:
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determining a phase of periodic noise on an input of the capacitive touch sensor; generating a periodic excitation signal having a phase that is locked to the determined phase of the periodic noise; applying the periodic excitation signal to an excited conductor in the first array; while the excitation signal is applied, detecting a response signal on a responding conductor in the second array, and generating, based on the detected response signal, a value indicative of a measured capacitance between the excited conductor and the responding conductor; accessing a threshold value; determining whether the response signal corresponds to a touch based on a difference between the value and the threshold value; and producing a signal reflecting results of the determination of whether the response signal corresponds to a touch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for providing cleaned signals in a capacitive touch screen display having a capacitive touch sensor positioned relative to a display device, the capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix, the method comprising:
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receiving a synchronization signal from the display device; configuring the touch sensor to have a sensor frame rate equal to a rational multiple of a frame rate of the display device; determining a phase of periodic noise generated by the display device based on the synchronization signal; during a first sensor frame of the touch sensor, generating a first periodic excitation signal having a phase that is locked to the determined phase of the periodic noise, and applying the first periodic excitation signal to an excited conductor in the first array; while the first excitation signal is applied during the first sensor frame, detecting a first response signal on a responding conductor in the second array, the responding conductor being capacitively coupled to the excited conductor, and generating, based on the detected first response signal, a first value indicative of a measured capacitance between the excited conductor and the responding conductor; accessing a first threshold value; determining whether the first response signal corresponds to a touch based on a difference between the first value and the first threshold value; and producing a signal reflecting results of the determination of whether the first response signal corresponds to a touch. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for providing cleaned signals in a capacitive touch screen display having a capacitive touch sensor positioned relative to a display device, the capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix, the method comprising:
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receiving a synchronization signal from the display device; configuring the touch sensor to have a ratio of a sensor frame rate to a frame rate of the display device that is equal to x;
y, where x and y are integers and x is greater than one;determining a phase of periodic noise generated by the display device based on the synchronization signal; storing x threshold values in a data store, each of the x threshold values usable for determining touches during a respective one of x sequential sensor frames; and during each nth sensor frame of the x sequential sensor frames, where n is an integer from 1 to x; generating an nth periodic excitation signal having a phase that is locked to the determined phase of the periodic noise, and applying the nth periodic excitation signal to an excited conductor in the first array; while the nth excitation signal is applied during the nth sensor frame, detecting an nth response signal on a responding conductor in the second array, the responding conductor being capacitively coupled to the excited conductor, and generating, based on the detected nth response signal, an nth value indicative of a measured capacitance between the excited conductor and the responding conductor; accessing, from the data store, an nth threshold value; determining whether the nth response signal corresponds to a touch based on a difference between the nth value and the nth threshold value; and producing a signal reflecting results of the determination of whether the nth response signal corresponds to a touch. - View Dependent Claims (36, 37, 38, 39, 40, 41)
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42. A system for providing a cleaned signal in a capacitive touch sensor, the system comprising:
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a capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix; and one or more circuits configured to; determine a phase of periodic noise on an input of the capacitive touch sensor; generate a periodic excitation signal having a phase that is locked to the determined phase of the periodic noise; apply the periodic excitation signal to an excited conductor in the first array; while the excitation signal is applied, detect a response signal on a responding conductor in the second array, and generate, based on the detected response signal, a value indicative of a measured capacitance between the excited conductor and the responding conductor; access a threshold value; determine whether the response signal corresponds to a touch based on a difference between the value and the threshold value; and produce a signal reflecting results of the determination of whether the response signal corresponds to a touch. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63)
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64. A system for providing cleaned signals in a capacitive touch screen display having a capacitive touch sensor positioned relative to a display device, the system including:
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a display device; a capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix; and one or more circuits configured to; receive a synchronization signal from the display device; configure the touch sensor to have a sensor frame rate equal to a rational multiple of a frame rate of the display device; determine a phase of periodic noise generated by the display device based on the synchronization signal; during a first sensor frame of the touch sensor, generate a first periodic excitation signal having a phase that is locked to the determined phase of the periodic noise, and applying the first periodic excitation signal to an excited conductor in the first array; while the first excitation signal is applied during the first sensor frame, detect a first response signal on a responding conductor in the second array, the responding conductor being capacitively coupled to the excited conductor, and generate, based on the detected first response signal, a first value indicative of a measured capacitance between the excited conductor and the responding conductor; access a first threshold value; determine whether the first response signal corresponds to a touch based on a difference between the first value and the first threshold value; and produce a signal reflecting results of the determination of whether the first response signal corresponds to a touch. - View Dependent Claims (65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75)
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76. A system for providing cleaned signals in a capacitive touch screen display having a capacitive touch sensor positioned relative to a display device, the system including:
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a display device; a data store; a capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix; and one or more circuits configured to; receive a synchronization signal from the display device; configure the touch sensor to have a ratio of a sensor frame rate to a frame rate of the display device that is equal to x;
y, where x and y are integers and x is greater than one;determine a phase of periodic noise generated by the display device based on the synchronization signal; store x threshold values in the data store, each of the x threshold values usable for determining touches during a respective one of x sequential sensor frames; and during each nth sensor frame of the x sequential sensor frames, where n is an integer from 1 to x; generate an nth periodic excitation signal having a phase that is locked to the determined phase of the periodic noise, and apply the nth periodic excitation signal to an excited conductor in the first array; while the nth excitation signal is applied during the nth sensor frame, detect an nth response signal on a responding conductor in the second array, the responding conductor being capacitively coupled to the excited conductor, and generate, based on the detected nth response signal, an nth value indicative of a measured capacitance between the excited conductor and the responding conductor; access, from the data store, an nth threshold value; determine whether the nth response signal corresponds to a touch based on a difference between the nth value and the nth threshold value; and produce a signal reflecting results of the determination of whether the nth response signal corresponds to a touch. - View Dependent Claims (77, 78, 79, 80, 81, 82)
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83. A system for providing a cleaned signal in a capacitive touch sensor, the system comprising:
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a capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix; means for determining a phase of periodic noise on an input of the capacitive touch sensor; means for generating a periodic excitation signal having a phase that is locked to the determined phase of the periodic noise; and one or more circuits configured to; apply the periodic excitation signal to an excited conductor in the first array; while the excitation signal is applied, detect a response signal on a responding conductor in the second array, and generate, based on the detected response signal, a value indicative of a measured capacitance between the excited conductor and the responding conductor; access a threshold value; determine whether the response signal corresponds to a touch based on a difference between the value and the threshold value; and produce a signal reflecting results of the determination of whether the response signal corresponds to a touch.
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84. A system for providing cleaned signals in a capacitive touch screen display having a capacitive touch sensor positioned relative to a display device, the system including:
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a display device; a capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix; a receiving circuit configured to receive a synchronization signal from the display device; means for configuring the touch sensor to have a sensor frame rate equal to a rational multiple of a frame rate of the display device; means for determining a phase of periodic noise generated by the display device based on the synchronization signal; means for, during a first sensor frame of the touch sensor, generate a first periodic excitation signal having a phase that is locked to the determined phase of the periodic noise, and applying the first periodic excitation signal to an excited conductor in the first array; and
one or more circuits configured to;while the first excitation signal is applied during the first sensor frame, detect a first response signal on a responding conductor in the second array, the responding conductor being capacitively coupled to the excited conductor, and generate, based on the detected first response signal, a first value indicative of a measured capacitance between the excited conductor and the responding conductor; access a first threshold value; determine whether the first response signal corresponds to a touch based on a difference between the first value and the first threshold value; and produce a signal reflecting results of the determination of whether the first response signal corresponds to a touch.
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85. A system for providing cleaned signals in a capacitive touch screen display having a capacitive touch sensor positioned relative to a display device, the system including:
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a display device; a data store; a capacitive touch sensor including a first array of conductors and a second array of conductors, wherein the conductors in the first array are arranged substantially in parallel with one another, and the conductors in the second array are arranged substantially in parallel with one another, and wherein the conductors in the first array are positioned substantially perpendicular to the conductors in the second array to form a matrix; a receiving circuit configured to receive a synchronization signal from the display device; means for configuring the touch sensor to have a ratio of a sensor frame rate to a frame rate of the display device that is equal to x;
y, where x and y are integers and x is greater than one;means for determining a phase of periodic noise generated by the display device based on the synchronization signal; and one or more circuits configured to; store x threshold values in the data store, each of the x threshold values usable for determining touches during a respective one of x sequential sensor frames; and during each nth sensor frame of the x sequential sensor frames, where n is an integer from 1 to x; generate an nth periodic excitation signal having a phase that is locked to the determined phase of the periodic noise, and apply the nth periodic excitation signal to an excited conductor in the first array; while the nth excitation signal is applied during the nth sensor frame, detect an nth response signal on a responding conductor in the second array, the responding conductor being capacitively coupled to the excited conductor, and generate, based on the detected nth response signal, an nth value indicative of a measured capacitance between the excited conductor and the responding conductor; access, from the data store, an nth threshold value; determine whether the nth response signal corresponds to a touch based on a difference between the nth value and the nth threshold value; and produce a signal reflecting results of the determination of whether the nth response signal corresponds to a touch.
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Specification