Shield Wiring Line for Touch Panel Signal Isolation
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Solution Overview
Problem
In touch panels that detect both the position and pressing force of a pointer, the proximity of position sensor wiring lines and pressing force sensor wiring lines leads to capacitive coupling, which deteriorates the accuracy of force and position detection.
Innovation Solution
Incorporating a shield wiring line between the position sensor wiring line and the pressing force sensor wiring line to inhibit capacitive coupling, ensuring accurate detection of pointer position and pressing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the position sensor wiring line and the pressing force sensor wiring line are disposed adjacent to each other on the same surface, then the device complexity is reduced and ease of manufacture is improved, but capacitive coupling occurs between the wiring lines which deteriorates the measurement precision of pointer position and pressing force
Solution Approach 1:
A shield wiring line is introduced as an intermediary element between the position sensor wiring line and the pressing force sensor wiring line. This shield wiring line acts as a mediator that blocks capacitive coupling between the two sensor wiring lines, thereby preventing signal interference while maintaining the compact layout structure.
Solution Approach 2:
The shield wiring line is extracted as a separate functional element from the sensor wiring lines. By isolating the shielding function into a dedicated component, the patent prevents capacitive coupling between the position and pressing force sensor wiring lines, thus improving measurement precision without complicating the overall manufacturing process.
2Device complexity
If the position sensor wiring line and the pressing force sensor wiring line are disposed adjacent to each other on the same surface, then the device structure is simplified, but the reliability of signal detection is worsened due to capacitive coupling affecting signal accuracy
Solution Approach 1:
The shield wiring line serves as a protective intermediary that blocks capacitive coupling between adjacent sensor wiring lines. This intermediary structure maintains signal integrity and detection reliability while preserving the simplified device architecture with all wiring lines on the same surface.
Solution Approach 2:
The shield wiring line converts the potential harmful effect of capacitive coupling into a beneficial shielding effect. By strategically placing the shield wiring line between the position and pressing force sensor wiring lines, the harmful capacitive interference is blocked, thereby improving signal detection reliability.
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 shield wiring line effectively reduces capacitive coupling, enhancing the detection accuracy of both pointer position and pressing force, thereby improving overall touch panel performance.
Implementation Method 1
the position sensor wiring line and the pressing force sensor wiring line are disposed adjacent to each other. In this case, it is considered that, as a result of the position sensor wiring line and the pressing force sensor wiring line being capacitively coupled, the change in the signal of the pressing force sensor electrode may affect the signal of the position sensor electrode
Data Source
AI summary
A touch panel includes a first substrate and a second substrate. The touch panel includes a drive electrode formed on a surface of the first substrate, a position sensor electrode and a pressing force sensor electrode formed on a surface of the second substrate, a position sensor wiring line that connects the position sensor electrode to a terminal portion, a pressing force sensor wiring line that connects the pressing force sensor electrode to the terminal portion, and a shield wiring line disposed between the position sensor wiring line and the pressing force sensor wiring line in a plan view.