Passive Stylus Orientation Detection on Capacitive Sense Arrays
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Solution Overview
Problem
Existing capacitive sense arrays struggle to effectively detect orientation information, such as tilting and rotational angles, of passive styluses without the need for electronic components, limiting user interaction capabilities.
Innovation Solution
Implementing a capacitive sense array that scans and processes capacitive sense signals using machine learning techniques to estimate the tilting and rotational angles of a passive stylus, leveraging a touch map generated from capacitive sense signals to determine orientation parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a passive stylus without electronic components is used, then the production and operating cost is reduced, but the ability to detect orientation information (tilting angle, rotational angle) is limited
Solution Approach 1:
The patent replaces the mechanical/electronic system (active stylus with electronic components) with a capacitive sensing system. The capacitive sense array detects changes in capacitance caused by the passive stylus's position and orientation, translating physical orientation into detectable electrical signals without requiring electronics in the stylus itself.
Solution Approach 2:
The patent introduces capacitive coupling as an intermediary mechanism between the passive stylus and the detection system. The stylus's conductive tip creates capacitive coupling with the capacitive sense array, allowing orientation information to be transmitted without direct electronic communication, thus maintaining passivity while enabling detection.
2Measurement precision
If machine learning techniques are implemented to process capacitive sense signals, then orientation information detection accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent applies machine learning models in advance to train the system on capacitive sense signal patterns corresponding to different orientations. This preliminary training enables the system to automatically recognize and interpret orientation information from raw capacitive signals during actual use, reducing the need for complex real-time processing algorithms.
Solution Approach 2:
The machine learning model performs self-learning and adaptation by processing capacitive sense signals and automatically extracting orientation parameters. The system improves its detection accuracy over time through continuous learning from data, reducing the need for manual programming and complex rule-based processing.
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 user experience by enabling precise emulation of pencil strokes and line variations through accurate detection of stylus orientation, improving interaction efficiency and effectiveness.
Implementation Method 1
capacitive sense array... The capacitances of these capacitive sense elements vary when an object (e.g., a finger, a hand, a stylus, or another object) comes into contact with or hovers above the touch sensing surface
Data Source
AI summary
An electronic device includes a capacitive sense array made of a plurality of sense electrodes. A subset of sense electrodes of the capacitive sense array is scanned to obtain a plurality of capacitive sense signals, and a touch map is generated from at least a subset of the capacitive sense array based on the plurality of capacitive sense signals. The electronic device determines that the touch map corresponds to a passive stylus. In accordance with a determination that the touch map corresponds to the passive stylus, the electronic device determines a stylus position and one or more orientation parameters of the passive stylus with respect to a surface of the capacitive sense array. In some embodiments, a stylus parameter determination model is applied to process the touch map and determine at least the one or more orientation parameters of the passive stylus.