Resonant Stylus Pen Detection Under Noise and Conductive Interference
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Solution Overview
Problem
Existing passive stylus pens face challenges in precise touch sensing due to noise interference and difficulty in signal transmission, and existing technologies have not adequately addressed the need for an effective method to improve touch sensitivity and signal transmission in environments with conductive objects, particularly in foldable and bendable devices.
Innovation Solution
A capacitive resonant stylus pen with a resonance circuit comprising a ferrite core, coil, and capacitor, designed to generate a sufficient output signal, reduce noise, and enhance touch sensing performance, even in the presence of conductive objects, using multiple resonant frequencies and an antenna module for efficient signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive stylus pen uses resonance with touch sensor driving signal, then touch position detection is enabled, but noise in similar frequency band greatly reduces sensing precision
Solution Approach 1:
The system dynamically adjusts the resonant frequency of the stylus pen away from the fixed driving frequency of the touch sensor when noise is detected. The controller monitors the sensing signal quality and modifies the resonant frequency in real-time to avoid frequency bands with high noise levels, thereby maintaining precise touch sensing despite the presence of electromagnetic noise in the environment.
Solution Approach 2:
The patent changes the resonant frequency parameter of the stylus pen based on environmental noise conditions. By measuring the noise spectrum and adjusting the resonant frequency to match cleaner frequency bands, the system optimizes the signal-to-noise ratio and maintains high sensing precision even when noise in the original frequency band interferes with detection.
2Reliability
If passive stylus pen touches with conductive object, then signal transmission occurs, but touch sensor fails to detect stylus touch depending on conductive object location or area
Solution Approach 1:
The system dynamically adjusts its operating parameters when conductive objects are detected near the touch sensor. The controller modifies the driving signal characteristics and resonant frequency to compensate for the capacitive coupling effects introduced by conductive objects, ensuring reliable stylus touch detection regardless of the conductive object's position or size on the screen.
Solution Approach 2:
The touch sensor system uses feedback from the sensing signals to detect the presence and characteristics of conductive objects. Based on this feedback, the controller adjusts the driving signal frequency and amplitude, and modifies the resonant frequency of the stylus pen to maintain reliable touch detection accuracy even when conductive objects are present on or near the display surface.
3Area of stationary object
If display screen size is increased, then user interface capability is improved, but signal transmission distance and precision become more difficult
Solution Approach 1:
The system dynamically adjusts the resonant frequency and signal characteristics based on the display screen size and touch electrode spacing. For larger screens with greater electrode distances, the controller modifies the driving signal amplitude and frequency to compensate for signal attenuation, maintaining precise touch detection across the entire extended display area.
Solution Approach 2:
The patent implements parameter changes in the resonant frequency and driving signal characteristics according to the display screen dimensions. By adapting these parameters to the specific screen size and electrode configuration, the system overcomes signal transmission challenges inherent in large-screen devices and maintains high measurement precision across the full display area.
4Adaptability or versatility
If active stylus pen provides additional functions, then user capability is enhanced, but battery charging becomes difficult and device cost increases
Solution Approach 1:
The passive stylus pen achieves multiple functions including pressure sensitivity, hovering detection, and button input without requiring a battery or complex electronic components. By utilizing the electromagnetic resonance between the stylus and touch sensor, the system provides versatile functionality that would normally require active electronics, thereby simplifying the stylus design while enhancing user capability.
Solution Approach 2:
The passive stylus pen uses the touch sensor's own driving signal to generate resonance and enable all stylus functions. Instead of requiring separate power sources and electronic components for each function, the stylus leverages the existing electromagnetic field from the touch sensor to provide pressure sensitivity, hovering detection, and other advanced features through passive resonance, eliminating the need for batteries and complex circuitry.
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
The capacitive resonant stylus pen effectively improves touch sensing precision and signal transmission, enabling reliable operation in environments with noise and conductive objects, and supports wireless charging and reduced power consumption.
Implementation Method 1
the stylus pen generates a signal by resonating with a driving signal applied to the touch sensor
Implementation Method 2
the stylus pen transmits and receives a signal through an electrical and/or magnetic method with the touch sensor
Implementation Method 3
A capacitive resonant stylus pen with a resonance circuit comprising a ferrite core, coil, and capacitor
Implementation Method 4
resonance circuit comprising a ferrite core, coil, and capacitor
Implementation Method 5
touch sensors are included in various electronic devices... the touch sensor receives the resonance signal of the stylus pen and detects a touch position
Data Source
AI summary
An electronic device according to an embodiment includes: a display panel; a touch electrode layer disposed on the display panel and comprising at least one touch electrode; and a conductive wire disposed on the display panel, disposed on the same layer as the touch electrode layer, and generating a magnetic field signal for driving a stylus pen.