Passive Stylus Resonance Circuit for Noise-Resistant Touch Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing passive stylus pens face challenges in signal transmission and reception due to noise interference, particularly when used near conductive objects, leading to reduced touch sensitivity and precision, and require separate components like EMR sensors and ICs, which increase thickness and cost.
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 and reduce noise, featuring a conductive blocking member to prevent eddy currents, and a touch device with dual driving modes to distinguish between stylus and conductive touch signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive stylus pen uses a resonance circuit to generate signals, then touch sensing capability is improved, but noise interference from conductive objects reduces measurement precision
Solution Approach 1:
The patent introduces a blocking member as an intermediary element between the resonance circuit and the external environment. This blocking member specifically blocks eddy currents induced by conductive objects, preventing noise interference while allowing the resonance circuit to function. The blocking member acts as a mediator that protects the sensitive resonance circuit from harmful electromagnetic effects without disrupting the signal generation capability.
Solution Approach 2:
The patent converts the harmful eddy currents induced by conductive objects into a beneficial filtering mechanism. By strategically placing the blocking member, the eddy currents are directed to flow through specific paths that do not interfere with the resonance circuit operation. The harmful electromagnetic induction effect is transformed into a controlled phenomenon that actually helps isolate the resonance circuit from noise.
2Measurement precision
If EMR sensors and ICs are added to improve stylus recognition, then touch sensing capability is improved, but device thickness and manufacturing cost increase
Solution Approach 1:
The patent makes the touch sensor panel serve multiple functions: it acts as both the display interface and the sensing element for the passive stylus pen. The resonance circuit in the stylus interacts with the existing touch sensor electrodes, eliminating the need for separate EMR sensors and ICs. This multi-functional approach allows the same hardware to perform both display and stylus recognition tasks.
Solution Approach 2:
The existing touch sensor infrastructure serves the dual purpose of display control and stylus detection. The resonance circuit in the passive stylus pen generates signals that are detected by the same touch sensor electrodes used for finger touch detection. The system essentially serves itself by using its existing sensing capability to detect the stylus, eliminating the need for dedicated stylus detection hardware.
3Measurement precision
If the resonance circuit output signal is increased to improve detection, then signal sensitivity is improved, but noise interference increases
Solution Approach 1:
The patent applies different properties to different parts of the system. The blocking member is strategically positioned only where eddy currents would interfere with the resonance circuit, while other areas remain open for signal transmission. This localized application of blocking properties allows the resonance circuit to operate at higher signal levels without experiencing noise interference in critical areas.
Solution Approach 2:
The patent segments the electromagnetic environment into distinct zones: a protected zone around the resonance circuit where eddy currents are blocked, and an open zone for signal transmission. The blocking member creates this segmentation, allowing the resonance circuit to generate stronger signals in its protected zone while maintaining communication capability in the open zone without noise interference.
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 solution enhances touch sensing performance by reducing noise, improving signal sensitivity, and allowing simultaneous use with conductive objects, while being thinner and more cost-effective than active stylus pens.
Implementation Method 1
The passive stylus pen generates a signal by resonating with a driving signal applied to the touch sensor
Implementation Method 2
The stylus pen may transmit and receive a signal through an electrical and/or magnetic method with the touch sensor
Implementation Method 3
an inductor part including a coil wound in multiple layers on at least a portion of the ferrite core
Implementation Method 4
a conductive blocking member to prevent eddy currents
Data Source
Figure 1(a)~2
Figure 3(a)~3(b)
Figure 4~5
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.