Stylus Uplink Phase Compensation for Palm Touch Interference
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Solution Overview
Problem
The reception of uplink signals at a stylus is degraded when a user's palm or body part touches the touchscreen, disrupting synchronization and degrading data transfer from the digitizer to the stylus, especially in ungrounded modes.
Innovation Solution
An adaptive uplink signal modification system that detects body touches and applies an antiphase signal selectively to the affected touch area, enhancing the combined signal strength at the stylus by adjusting the phase difference between the digitizer and stylus paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a user's palm or body part touches the touchscreen during stylus operation, then the user can perform body touch input, but the uplink signal reception at the stylus is degraded and synchronization is disrupted
Solution Approach 1:
The touchscreen is divided into multiple touch-sensitive areas with independent control. When a body touch is detected in a specific area, the system selectively modifies the uplink signal only for that particular area rather than the entire screen, allowing body touch input to function while maintaining stylus signal integrity in other regions
Solution Approach 2:
Different regions of the touchscreen are assigned different signal characteristics. The body touch area receives an antiphase signal to cancel unwanted capacitance changes, while other areas maintain normal uplink signal transmission. This local differentiation allows simultaneous body touch functionality and stylus reliability
2Reliability
If the uplink signal phase is modified to compensate for body touch interference, then signal strength at the stylus is enhanced, but the system complexity increases due to phase detection and selective application requirements
Solution Approach 1:
The system continuously monitors touch screen activity and automatically detects when a body touch occurs. Based on this feedback, the controller selectively applies phase modification only to the affected area during the body touch event, then returns to normal operation. This feedback mechanism enables automatic adaptation without requiring complex manual configuration
Solution Approach 2:
The uplink signal phase is made dynamic rather than static. The system can switch between normal phase and antiphase configuration based on real-time detection of body touch events. This dynamic adjustment allows the system to maintain simplicity during normal operation while providing enhanced signal strength only when and where needed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances stylus performance by compensating for signal loss due to body touches, ensuring stable data transfer and synchronization with the touchscreen.
Implementation Method 1
A touch position of the input device can be detected due to a small change in capacitance at a contact point on the touch screen
Implementation Method 2
an uplink signal modulator for changing a phase angle of the uplink signal to obtain an antiphase signal
Data Source
AI summary
An apparatus and method for compensating the effect of a contact by a hand or other body part of a user with a touch screen of a host device while holding an input device on the strength of a capacitively coupled uplink signal provided to the input device (e.g. stylus) by the host device. The compensation is achieved by applying an antiphase signal on a selective contact area (e.g. under a palm area), to increase an overall induced signal collected by the input device from digitizer-to-pen and palm-to-pen paths.