Stylus Touch Shielding Structure for Stable Inductance Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing touch input devices experience signal attenuation and inductance value variation in resonance circuits due to stylus pen motions, making it difficult to distinguish between approaching or tilting motions and pen-pressure motions.
Innovation Solution
A touch input device with a shielding unit comprising a magnetic shielding sheet and conductive layer, having specific permeability and thickness, to minimize signal attenuation and inductance value changes caused by stylus pen motions, ensuring a ±10% change rate in inductance value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shielding unit is added to minimize signal attenuation, then signal amplitude is improved, but device complexity increases
Solution Approach 1:
A shielding unit comprising a magnetic shielding sheet and a conductive layer is introduced as an intermediary component between the stylus pen and the sensor unit. This shielding unit minimizes signal attenuation by controlling electromagnetic interference while maintaining signal transmission, thus improving signal amplitude without requiring fundamental changes to the touch input device architecture.
2Measurement precision
If shielding materials are added to maintain inductance stability, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The shielding unit acts as a mediator that stabilizes the inductance value of the resonance circuit unit during stylus pen motions. By incorporating specific magnetic shielding materials and conductive layers, the system maintains measurement precision without requiring complex control algorithms or additional sensing components.
3Measurement precision
If the shielding unit parameters are optimized to minimize inductance variation, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies optimal parameter ranges for the shielding unit (permeability: 10-300, thickness: 10-300 μm) that balance measurement precision and manufacturing feasibility. By defining these parameter ranges, the patent enables manufacturers to achieve inductance stability without requiring extreme manufacturing precision, as the system performs adequately within these specified ranges.
Solution Approach 2:
The shielding unit employs a composite structure combining magnetic shielding sheet and conductive layer, which together provide complementary functions. This composite approach allows each layer to be manufactured within reasonable precision tolerances while achieving the combined effect of signal shielding and inductance stabilization that would be difficult with a single material.
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 device effectively minimizes signal attenuation and distinguishes between stylus pen motions, maintaining signal amplitude and inductance stability during approaching or tilting, enhancing motion recognition accuracy.
Implementation Method 1
a shielding unit disposed below the display unit, in which the shielding unit has a permeability and a thickness, which allow a change rate of an inductance value of the resonant circuit unit to be -10% to +10% of a reference inductance value
Data Source
AI summary
A touch input device according to an embodiment of the present invention drives a stylus pen including a resonance circuit unit and senses a pen signal from the stylus pen, and comprises: a cover layer; a sensor unit which is arranged below the cover layer, and which includes at least one pattern for driving the stylus pen and sensing the pen signal; a display unit arranged below the sensor unit; and a shielding unit arranged below the display unit, wherein the shielding unit has a permeability and a thickness that allows the change rate of an inductance value of the resonance circuit unit to be −10% to +10% of a reference inductance value.