Active Stylus Touch Screen With Synchronized Electric Field
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Solution Overview
Problem
Existing touch screen systems face challenges in accurately recognizing touch positions, particularly with multi-touch recognition using fingers and active styluses, due to difficulties in differentiating between the changes in capacitance caused by fingers and styluses, and in precisely determining touched positions with active styluses that continuously generate electric fields.
Innovation Solution
A touch screen system with an optimized electrode pattern and an active stylus that synchronizes electric field generation with driving signals, allowing for precise multi-touch recognition by differentiating capacitance changes and amplifying the electric field only when necessary to avoid interference with other sensing cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an active stylus continuously generates an electric field to improve touch detection, then the electric field can be sensed by sensing cells, but the continuous electric field interferes with other sensing cells and makes it difficult to determine precise touched positions
Solution Approach 1:
The active stylus generates an electric field periodically in synchronization with the driving signals of the touch screen panel, rather than continuously. This periodic generation allows the stylus to interact with sensing cells only when they are actively being driven, preventing interference with other sensing cells that are not currently being driven.
Solution Approach 2:
The active stylus senses the electric field generated by the driving signal and amplifies it in synchronization with the driving signal. This feedback mechanism ensures that the stylus only generates electric field when the corresponding driving signal is active, creating a coordinated interaction that eliminates interference with other sensing cells.
2Measurement precision
If a passive stylus is used to achieve sharp touch recognition, then the change in capacitance at the touched surface can be detected, but the capacitance change is very slight and difficult to detect
Solution Approach 1:
The active stylus acts as an intermediary by generating its own electric field that interacts with the sensing cells. Instead of relying on the slight capacitance change of a passive stylus, the active stylus creates a measurable electric field that can be detected by the sensing cells, significantly improving detection capability.
Solution Approach 2:
The active stylus changes the electrical parameter by generating an electric field that synchronizes with the driving signal. This parameter change transforms the detection from measuring slight capacitance changes to measuring synchronized electric field interactions, making the signal much more detectable and measurable.
3Measurement precision
If driving electrodes and sensing electrodes have different areas to optimize stylus recognition, then the electrode pattern can be optimized for active stylus, but the electrode structure becomes more complex
Solution Approach 1:
The driving electrodes and sensing electrodes are designed with different areas in specific local regions to optimize stylus recognition. The electrode areas are varied locally where needed for stylus interaction, while maintaining a regular pattern in other regions, thus achieving optimization without excessive overall complexity.
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 system achieves improved accuracy in multi-touch recognition by both fingers and active styluses, enabling precise detection of touch positions and overcoming the limitations of continuous electric field interference.
Implementation Method 1
an active stylus separated from the touch screen panel, the active stylus being configured to output an electric field in synchronization with driving signals that are applied to the driving lines coupled to the driving electrodes adjacent to the active stylus
Implementation Method 2
the capacitive type touch screen panel detects a change in capacitance formed in sensing cells that are positioned at the touched surface to recognize the touched positions
Data Source
Figure 1
Figure 2~3A
Figure 3B
AI summary
A touch screen system (100) according to an exemplary embodiment of the present invention includes: a touch screen panel (110) including a plurality of driving electrodes (170a, 270a, 370a, 370a') coupled to a plurality of driving lines (112, X1, X2, X3, Xn) that extend in a first direction and a plurality of sensing electrodes (170b, 270b, 370b, 370b') coupled to a plurality of sensing lines (114, Y1, Y2, Y3, Ym) that extend in a second direction crossing the first direction, the driving electrodes (170a, 270a, 370a, 370a') and the sensing electrodes (170b, 270b, 370b, 370b') being alternately arranged so as not to overlap with each other; and an active stylus (160) separated from the touch screen panel (110), the active stylus (160) being configured to output an electric field in synchronization with driving signals that are applied to the driving lines (112, X1, X2, X3, Xn) coupled to the driving electrodes (170a, 270a, 370a, 370a') that are adjacent to the active stylus (160), wherein the driving electrodes (170a, 270a, 370a, 370a') and the sensing electrodes (170b, 270b, 370b, 370b') have different areas.