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1. WO2018128912 - POSITION, TILT, AND TWIST DETECTION FOR STYLUS

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CLAIMS

1. A touch-sensitive display device, comprising:

a touch sensor having a plurality of display electrodes; and

control logic coupled to the plurality of display electrodes, the control logic being configured to:

receive, for each of a plurality of stylus electrodes of an active stylus interacting with the touch-sensitive display device, a spatial capacitance measurement over the touch sensor for that stylus electrode; and

determine, relative to the touch sensor, and based on spatial capacitance measurements of the stylus electrodes, (i) a tip position of the active stylus, (ii) a tilt parameter of the active stylus, and (iii) a twist parameter of the active stylus.

2. The touch-sensitive display device of claim 1, where the control logic receives two spatial capacitance measurements corresponding to two stylus electrodes of the active stylus, including a tip electrode and a ring electrode.

3. The touch-sensitive display device of claim 2, where the ring electrode of the active stylus is asymmetrical relative to an elongate axis of the active stylus.

4. The touch-sensitive display device of claim 1, where the control logic receives three spatial capacitance measurements corresponding to three stylus electrodes of the active stylus, including a first tip electrode, a second tip electrode, and a ring electrode.

5. The touch-sensitive display device of claim 4, where spatial capacitance measurements received for the first and second tip electrodes are used by the control logic to calculate respective positions of the first and second tip electrodes relative to the touch sensor, and these positions are used collectively by the control logic to calculate the tip position of the stylus.

6. The touch-sensitive display device of claim 4, where the tilt parameter is calculated by the control logic based on a distance between a spatial capacitance measurement received for the ring electrode and spatial capacitance measurements received for the first and second tip electrodes.

7. The touch-sensitive display device of claim 4, where spatial capacitance measurements received for the first and second tip electrodes are used by the control logic to calculate respective positions of the first and second tip electrodes relative to the touch sensor, and the twist parameter of the active stylus is calculated by the control logic based on an angle of a reference line running between the respective positions of the first and second tip electrodes.

8. The touch-sensitive display device of claim 1, where during a single touch-sensing frame, spatial capacitance measurements for each of the plurality of stylus electrodes of the active stylus are made separately during different touch-sensing subframes.

9. The touch-sensitive display device of claim 8, where the spatial capacitance measurements made during each of the different touch-sensing subframes are collectively used by the control logic to determine one or more of the tip position, tilt parameter and twist parameter, and where the control logic is further configured to correct one or more of such determinations based on an estimated velocity of the active stylus.

10. The touch-sensitive display device of claim 1, where the control logic is further configured to apply a drive signal to each of the plurality of display electrodes, thereby influencing electrical conditions at one or more stylus electrodes of the active stylus to enable one or more of the spatial capacitance measurements.

11. The touch-sensitive display device of claim 10, where spatial capacitance measurements received for each of the plurality of stylus electrodes are calculated by the active stylus based on the electrical conditions influenced by the drive signal applied to each of the plurality of display electrodes, and the control logic receives the spatial capacitance measurements calculated by the active stylus via a communications interface of the touch-sensitive display device.

12. The touch-sensitive display device of claim 1, where the control logic is configured to calculate spatial capacitance measurements for each of the plurality of stylus electrodes based on electrical conditions detected at one or more display electrodes, the electrical conditions being influenced by a drive signal applied to one or more of the plurality of stylus electrodes of the active stylus.

13. The touch-sensitive display device of claim 1, where spatial capacitance measurements received for each of the plurality of stylus electrodes are collectively transformed into the tip position, the tilt parameter, and the twist parameter by an iteratively developed interpolation function.