Noise reduction for touch sensor system with active stylus
First Claim
1. Apparatus that is responsive to input from a stylus, comprising:
- a touch sensor having edges and having a plurality of electrodes; and
touch sensor circuitry that processes signals from the plurality of electrodes, wherein the touch sensor circuitry obtains signal data from the plurality of electrodes including pen present data from pen present electrodes where the stylus is located on the touch sensor and noise data from noise electrodes adjacent to the pen present electrodes, wherein the touch sensor circuitry includes a processor that removes the noise data from the pen present data to produce noise-removed pen present data, wherein the noise electrodes include at least four electrodes adjacent to the pen present electrodes, and wherein the processor includes a noise correction module that removes the noise data from the pen present data by computing a mean of the noise data on the noise electrodes.
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Accused Products
Abstract
A touch sensor may overlap a display. A transparent shield layer that is grounded around its edges may be interposed between the display and the touch sensor to help prevent noise from display data lines from reaching the touch sensor. The data lines may extend along a first dimension. The touch sensor may have first elongated electrodes that extend along the first dimension and second elongated electrodes that extend along a second dimension that is perpendicular to the first dimension. The second electrodes may be interposed between the first electrodes and the data lines. Pen present electrodes may be used to gather pen present data associated with a stylus on the touch sensor. Adjacent noise sensors may collect noise data that is removed from the pen present data.
17 Citations
22 Claims
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1. Apparatus that is responsive to input from a stylus, comprising:
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a touch sensor having edges and having a plurality of electrodes; and touch sensor circuitry that processes signals from the plurality of electrodes, wherein the touch sensor circuitry obtains signal data from the plurality of electrodes including pen present data from pen present electrodes where the stylus is located on the touch sensor and noise data from noise electrodes adjacent to the pen present electrodes, wherein the touch sensor circuitry includes a processor that removes the noise data from the pen present data to produce noise-removed pen present data, wherein the noise electrodes include at least four electrodes adjacent to the pen present electrodes, and wherein the processor includes a noise correction module that removes the noise data from the pen present data by computing a mean of the noise data on the noise electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A touch sensor display that receives input from a stylus, comprising:
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display layers that produce images, wherein the display layers include data lines and have edges; a conductive transparent shield layer that overlaps the display layers and that is grounded at the edges; touch sensor electrodes on the display layers that receive noise from the data lines; and touch sensor circuitry that processes signals from the electrodes, wherein the touch sensor circuitry obtains pen present data from pen present electrodes associated with presence of the stylus and noise data from noise electrodes adjacent to the pen present electrodes and that removes the noise data from the pen present data, wherein the pen present electrodes have first and second opposing sides, wherein there are at least two adjacent noise electrodes on the first side of the pen present electrodes when the pen present electrodes are located away from the edges of the display layers, and wherein there are at least two adjacent noise electrodes on the second side of the pen present electrodes when the pen present electrodes are located away from the edges of the display layers. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of determining where a stylus is located on a touch sensor, comprising:
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with front end circuitry in a touch sensor circuit, measuring pen present data on at least one pen present touch sensor electrode associated with a presence of the stylus on the touch sensor and measuring noise data on first and second sets of touch sensor noise electrodes that are adjacent to the at least one pen present touch sensor electrode and that are located on opposing sides of the at least one pen present touch sensor electrode, wherein the first and second sets of adjacent touch sensor noise electrodes each include fewer than four touch sensor noise electrodes; and with the touch sensor circuit, removing noise from the pen present data based on the measured noise data. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification