Stylus Tilt Detection via Dual-Electrode Frequency Signals
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Solution Overview
Problem
Existing touch technologies face challenges in achieving high precision and accurately determining the tilt angle of active capacitive styluses relative to touch panels, which is crucial for precise gesture recognition and stroke implementation.
Innovation Solution
The use of a stylus with a first and second emitting electrode, emitting different electrical signals at distinct frequencies, and a touch panel with a processing circuit to detect these signals and calculate the tilt angle, allowing for accurate localization of the stylus tip and recognition of user gestures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single emitting electrode is used in the stylus, then the device structure is simple, but the tilt angle detection precision is insufficient
Solution Approach 1:
The single emitting electrode is segmented into multiple emitting electrodes (first emitting electrode and second emitting electrode) arranged along the extension direction of the stylus. Each electrode emits electrical signals at different frequencies, enabling the touch panel to detect the tilt angle by comparing signal strengths from different positions, thus improving measurement precision while maintaining reasonable device complexity
Solution Approach 2:
The solution transitions from a single-point emission model to a multi-point linear arrangement of emitting electrodes. By distributing electrodes along the stylus extension direction and using frequency differentiation, the system adds spatial dimension information to the signal emission process, enabling tilt angle detection through positional signal comparison
2Measurement precision
If multiple electrical signals with different frequencies are emitted, then the tilt angle can be accurately determined, but the signal processing complexity increases
Solution Approach 1:
Each emitting electrode emits electrical signals in periodic time periods with distinct frequencies (first frequency for first electrode, second frequency for second electrode). The touch panel receives and processes these periodic signals by identifying their respective frequencies and comparing signal strengths, enabling tilt angle calculation through frequency-based signal differentiation without requiring complex simultaneous multi-signal processing
Solution Approach 2:
Frequency serves as an intermediary parameter that distinguishes signals from different emitting electrodes. By assigning unique frequencies to each electrode and using frequency as the identification key in signal processing, the system simplifies the complexity of handling multiple simultaneous signals, as the touch panel can separately process and compare signals based on their frequency characteristics
3Length of moving object
If the emitting electrodes are placed close together, then the stylus length is reduced, but the tilt angle detection resolution decreases
Solution Approach 1:
The system changes the identification parameter from spatial distance alone to a combination of frequency and signal strength. By assigning different frequencies to electrodes regardless of their spacing, the touch panel can accurately distinguish and compare signals from different electrodes even when they are closely positioned, maintaining tilt angle detection resolution without requiring large electrode separation distances
Data Source
AI summary
A stylus (100), a touch panel (200), a display device and a touch sensing method are provided. The stylus (100) includes: a first emitting electrode (12); a second emitting electrode (13), wherein a distance between the first emitting electrode (12) and the second emitting electrode (13) in an extension direction of the stylus (100) is greater than zero; and an emitting circuit (11), which is connected to the first emitting electrode (12) and the second emitting electrode (13), respectively. The emitting circuit (11) is used to emit a first electrical signal outwards through the first emitting electrode (12) and to emit a second electrical signal outwards through the second emitting electrode (13), so that the touch panel (200) determines a tilt angle (A1) of the stylus (100) relative to the touch panel (200) according to the received first and second electrical signals.