Capacitive Touch Panel Shielding for Electromagnetic Noise
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Solution Overview
Problem
Conventional resistive film touch panels face reduced detection accuracy and durability issues as screen size increases, and capacitive touch panels are prone to noise from external electromagnetic waves when using individual switch electrodes for menu display.
Innovation Solution
A capacitive touch panel design featuring multiple first and second electrodes, wiring lines, a switch electrode, and shield sections, where the shield sections are positioned to cover longer second and third wiring lines to suppress electromagnetic noise, and the switch electrodes are configured for reliable operation and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive touch panel uses individual switch electrodes for menu display, then menu operation reliability is improved, but the panel becomes prone to noise from external electromagnetic waves
Solution Approach 1:
A shield electrode is introduced as an intermediary element between the external environment and the wiring lines/switch electrodes. The shield electrode acts as a mediator that intercepts and grounds electromagnetic waves, preventing them from reaching the sensitive internal components. This resolves the contradiction by adding a protective intermediary that blocks harmful electromagnetic noise while allowing the switch electrode menu operation to function reliably.
2Area of stationary object
If screen size is increased, then display area is improved, but detection accuracy and durability are reduced
Solution Approach 1:
The touch panel surface is segmented into multiple independent first electrodes and second electrodes arranged in grid patterns. This segmentation allows each electrode to maintain precise detection capabilities while collectively covering a larger display area. The divided electrode structure enables the panel to scale up in size without sacrificing detection accuracy, as each segment operates independently with maintained electrode spacing and dimensions.
3Area of stationary object
If wiring lines are extended to cover larger area, then electrode connectivity is improved, but electromagnetic noise interference increases
Solution Approach 1:
The shield electrode serves as a protective intermediary positioned between external electromagnetic sources and the extended wiring lines. By placing the shield electrode closer to the wiring lines and connecting it to ground, the patent creates a protective barrier that intercepts electromagnetic noise before it can interfere with signal transmission, enabling extended wiring coverage without proportionally increased noise interference.
Solution Approach 2:
The harmful electromagnetic noise is extracted and redirected to ground through the shield electrode. The shield electrode captures the electromagnetic interference that would otherwise affect the wiring lines and switch electrodes, separating the noise pathway from the signal pathway. This extraction of harmful factors allows the wiring lines to extend across larger areas without proportionally increasing noise susceptibility.
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 design enhances detection accuracy and durability while preventing faulty operations due to electromagnetic interference, allowing for reliable menu operation and full utilization of the display area.
Implementation Method 1
a shield section insulated from the second wiring lines and the third wiring line, and disposed to cover the second wiring lines and the third wiring line
Data Source
AI summary
A touch panel includes multiple first electrodes, multiple first wiring lines, multiple second electrodes, multiple second wiring lines, a switch electrode, a third wiring line, and a shield section. The first electrodes are disposed parallel to each other in the first direction. The second electrodes intersect with the first electrodes, and are disposed parallel to each other in the second direction. The shield section is insulated from the second wiring lines and the third wiring lines, and is disposed to cover the second wiring lines and the third wiring lines.