Noise blanking for capacitive touch displays
AssigneePixart Imaging Inc.
InventorsKenneth Crandall, Michael Brosnan, Sam Sen Li
Life of this patent
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AssigneePixart Imaging Inc.
InventorsKenneth Crandall, Michael Brosnan, Sam Sen Li
Estimating the term…
Disclosed are various embodiments of a capacitive touchscreen or touch panel system comprising a controller operably connected to a first plurality of drive electrodes and a second plurality of sense electrodes. The controller includes a noise disruption detector circuit, a user noise source detector/anticipator circuit, clock control logic circuitry operably connected to the noise disruption detector circuit and to the user noise source detector/anticipator circuit, at least one static-clocked digital filter circuit operably connected to and controlled by the clock control logic circuitry, a central processing unit (CPU) operably connected to the clock control logic circuitry, firmware operably connected to the CPU; and touch position circuitry configured to deliver signals indicative of touch positions on the touchscreen to a host controller. The controller is configured to employ at least one of the CPU and the firmware to cause the clock control logic circuitry to inhibit operation of the digital filter circuit in response to a signal representative of excessive noise levels being provided by either the noise disruption detector circuit or the user noise source detector/anticipator circuit.
A capacitive touchscreen or touch panel system, comprising:
A method of operating a capacitive touchscreen or touch panel system comprising a touchscreen, the touchscreen comprising a first plurality of electrically conductive drive electrodes arranged in rows or columns, and a second plurality of electrically conductive sense electrodes arranged in rows or columns arranged at an angle with respect to the rows or columns of the first plurality of electrodes, mutual capacitances existing between the first and second pluralities of electrodes at locations where the first and second pluralities of electrodes intersect, the mutual capacitances changing in the presence of one or more fingers of a user or touch devices brought into proximity thereto, drive circuitry operably connected to the first plurality of drive electrodes, sense circuitry operably connected to the second plurality of sense electrodes and configured to sense input signals therefrom, and a controller operably connected to the first plurality of drive electrodes and the second plurality of sense electrodes, the controller comprising a noise disruption detector circuit, a user noise source detector/anticipator circuit, clock control logic circuitry operably connected to the noise disruption detector circuit and to the user noise source detector/anticipator circuit, at least one static-clocked digital filter circuit operably connected to and controlled by the clock control logic circuitry, a central processing unit (CPU) operably connected to the clock control logic circuitry, firmware operably connected to the CPU, and touch position circuitry configured to deliver signals indicative of touch positions on the touchscreen to a host controller, wherein the controller is configured to employ at least one of the CPU and the firmware to cause the clock control logic circuitry to inhibit operation of the digital filter circuit in response to a signal representative of excessive noise levels being provided by either the noise disruption detector circuit or the user noise source detector/anticipator circuit, the method comprising causing the clocked control logic circuitry to inhibit operation of the digital filter circuitry in response to the excessive noise signal being provided.
Dependencies are inferred from the claim text.