NOISE REDUCTION IN CAPACITIVE TOUCH SENSORS
First Claim
Patent Images
1. A touch sensing display device, comprising:
- a display;
a display controller circuit including display scanning circuitry and a controller arranged to control a duty cycle of scanning of the display; and
a capacitive touch sensor comprising at least one electrode in proximity to the display;
a touch sensor controller circuit arranged to control a sensor acquisition duty cycle with respect to a signal from the capacitive touch sensor,wherein at least one of the controller circuits is configured such that a portion of each of the sensor acquisition duty cycles occurs within a period of reduced noise from a duty cycle of the scanning of the display.
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Accused Products
Abstract
In touch sensitive display devices, the display scanning circuitry responsible for driving images of the panel screen can cause noise on the electrodes of nearby touch sensors. The display controller circuit and/or the touch sensor controller circuit of the exemplary touchscreen display devices may be configured to reduce such noise during the touch sensor acquisition cycle by implementing one or more of several techniques in which a portion of each of the sensor acquisition cycles occurs within a period of reduced noise from a cycle of the scanning of the display.
87 Citations
37 Claims
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1. A touch sensing display device, comprising:
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a display; a display controller circuit including display scanning circuitry and a controller arranged to control a duty cycle of scanning of the display; and a capacitive touch sensor comprising at least one electrode in proximity to the display; a touch sensor controller circuit arranged to control a sensor acquisition duty cycle with respect to a signal from the capacitive touch sensor, wherein at least one of the controller circuits is configured such that a portion of each of the sensor acquisition duty cycles occurs within a period of reduced noise from a duty cycle of the scanning of the display. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A circuit for controlling a display scanning duty cycle in a device having a capacitive touch sensor and a touch sensor controller circuit configured to control a sensor acquisition cycle, the circuit for controlling display scanning duty cycle comprising:
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display scanning circuitry for connecting to display lines coupled to drive picture elements of the display; scanning select circuitry arranged to select the display lines and hence the picture elements to be driven; and a display controller circuit for initiating and coordinating the driving of display lines, wherein; the display controller circuit is configured to control a display scanning duty cycle to cause periods of reduced display scanning noise, and the periods of reduced noise exceed duration of the sensor acquisition cycle. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A circuit for controlling a touch sensor acquisition duty cycle in a device having a display driven by display scanning circuitry according to a display scanning duty cycle and capacitive touch sensor electrodes, the circuit for controlling the touch sensor acquisition duty cycle comprising:
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a plurality of pins for connecting to the capacitive touch sensor electrodes; sensor drive and sample circuitry connected to the pins, and arranged to measure signals at touch channels and to determine which signals are indicative of a touch event at a channel; and a controller circuit configured to control touch sensor acquisition cycles to occur at least substantially within periods subject to reduced noise from display scanning duty cycles. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method of operating a touch sensing display device having (i) a display with display scanning circuitry for generating visual images on the display and a display controller circuit, and (ii) capacitive touch sensor circuitry including a touch sensor controller circuit capable of driving and sampling to detect touch events relating to the display, the method comprising:
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operating the display controller circuit to control display scanning activities; operating the touch sensor controller circuit to control driving and sampling from at least one touch sensor electrode, wherein; the controller circuits control display scanning and touch sensor acquisition according to regimes to reduce display scanning noise detectable by the touch sensor controller circuit during a sensor acquisition cycle.
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36. A device, comprising:
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an intermittent noise source; a capacitive touch sensor comprising at least one electrode in proximity to the intermittent noise source; a touch sensor controller circuit arranged to control a sensor acquisition duty cycle with respect to a signal from the capacitive touch sensor, wherein at least one of the noise source or the touch sense controller circuit is configured such that a portion of each of the sensor acquisition duty cycles occurs within a period of reduced noise of the intermittent noise source.
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37. A method of operating device having (i) an intermittent noise source, and (ii) capacitive touch sensor circuitry including a touch sensor controller circuit capable of driving and sampling to detect touch events relating to the device, the method comprising:
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operating the noise source for a first purpose within the device; operating the touch sensor controller circuit to control driving and sampling from at least one touch sensor electrode, wherein; the device controls noise generation and touch sensor acquisition according to regimes to reduce noise from the source detectable by the touch sensor controller circuit during a sensor acquisition cycle.
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Specification