Abstract: The disclosure herein describes coupling a stylus and a computing device. Based on a tip of a stylus being brought proximate to a display of a computing device configured to communicate in accordance with a wireless protocol, the computing device is configured to receive a stylus wireless protocol identifier and transmit a wireless protocol identifier of the computing device and one or more security keys to the stylus via a communication channel in response, whereby the stylus and computing device are coupled. Based on receiving a signal associated with user input from the coupled stylus using the wireless protocol, the computing device performs an operation based on the signal. The described “loose coupling” enables streamlined use of styluses with compatible computing devices without requiring full pairing.

Abstract: Examples are disclosed herein that relate to various operational modes of a capacitive touch sensor. One example provides a touch-sensitive input device comprising receive circuitry, a capacitive touch sensor having a plurality of portions, and a controller. The controller is configured to, responsive to not detecting a finger or a pen, operate the touch sensor in a locating mode by successively driving each portion with a fixed DC voltage and multiplexing the portion to the receive circuitry in a predefined sequence, and responsive to detecting the pen, operate the touch sensor in a tracking mode by driving a selected portion with the fixed DC voltage and multiplexing the selected portion to the receive circuitry to track the pen, the selected portion selected based on a detected location of the pen relative to the touch sensor and being varied as the detected location changes.

Abstract: The disclosure herein describes coupling a stylus and a computing device. Based on a tip of a stylus being brought proximate to a display of a computing device configured to communicate in accordance with a wireless protocol, the computing device is configured to receive a stylus wireless protocol identifier and transmit a wireless protocol identifier of the computing device and one or more security keys to the stylus via a communication channel in response, whereby the stylus and computing device are coupled. Based on receiving a signal associated with user input from the coupled stylus using the wireless protocol, the computing device performs an operation based on the signal. The described “loose coupling” enables streamlined use of styluses with compatible computing devices without requiring full pairing.

Abstract: Detecting touch input includes, over a series of touch-sensing time frames, interpreting electrical conditions of display electrodes of a touch-sensitive display device to estimate frame-by-frame positions of two or more stylus electrodes of an active stylus. Based on the estimated frame-by-frame positions, future positions of each of the two or more stylus electrodes during a future touch-sensing time frame are predicted. Regions of interest on the touch-sensitive display device are identified, each region of interest including a plurality of display electrodes surrounding the predicted future position of a stylus electrode of the two or more stylus electrodes. During the future touch-sensing time frame, display electrodes in the regions of interest are selectively scanned.

Abstract: Detecting touch input includes, over a series of touch-sensing time frames, interpreting electrical conditions of display electrodes of a touch-sensitive display device to estimate frame-by-frame positions of two or more stylus electrodes of an active stylus. Based on the estimated frame-by-frame positions, future positions of each of the two or more stylus electrodes during a future touch-sensing time frame are predicted. Regions of interest on the touch-sensitive display device are identified, each region of interest including a plurality of display electrodes surrounding the predicted future position of a stylus electrode of the two or more stylus electrodes. During the future touch-sensing time frame, display electrodes in the regions of interest are selectively scanned.

Abstract: Examples are disclosed herein that relate to various operational modes of a capacitive touch sensor. One example provides a touch-sensitive input device comprising receive circuitry, a capacitive touch sensor having a plurality of portions, and a controller. The controller is configured to, responsive to not detecting a finger or a pen, operate the touch sensor in a locating mode by successively driving each portion with a fixed DC voltage and multiplexing the portion to the receive circuitry in a predefined sequence, and responsive to detecting the pen, operate the touch sensor in a tracking mode by driving a selected portion with the fixed DC voltage and multiplexing the selected portion to the receive circuitry to track the pen, the selected portion selected based on a detected location of the pen relative to the touch sensor and being varied as the detected location changes.

Abstract: Present disclosure provides techniques to compensate for the above-identified signal processing delays between an in-cell digitizer of the touch screen display system and a stylus (or pen). In one example, the delays may be compensated by estimating the stylus-digitizer phase error on the digitizer side and adjusting for the delay accordingly. Specifically, in this example, the digitizer may utilize a quadratic receiver to perform an in-phase and quadratic detection in time domain in order to estimate the phase error. Based on the in-phase and quadratic detection, the digitizer may adapt the subsequent stylus sampling windows to compensate for the detected phase error. In another example, the stylus may transmit a first signal and a second signal that is 90 degrees delayed during a predetermined time slot, and to adapt the stylus sampling windows on the digitizer side in order to compensate for the phase delay.

Abstract: Present disclosure provides techniques to compensate for the above-identified signal processing delays between an in-cell digitizer of the touch screen display system and a stylus (or pen). In one example, the delays may be compensated by estimating the stylus-digitizer phase error on the digitizer side and adjusting for the delay accordingly. Specifically, in this example, the digitizer may utilize a quadratic receiver to perform an in-phase and quadratic detection in time domain in order to estimate the phase error. Based on the in-phase and quadratic detection, the digitizer may adapt the subsequent stylus sampling windows to compensate for the detected phase error. In another example, the stylus may transmit a first signal and a second signal that is 90 degrees delayed during a predetermined time slot, and to adapt the stylus sampling windows on the digitizer side in order to compensate for the phase delay.