Touch Display Shield Electrode Mesh for EMI and Capacitance Control
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Solution Overview
Problem
Existing display devices face challenges in maintaining sensitivity of electrostatic capacitance type sensors due to capacitive coupling between wiring lines and power lines, which can lead to deteriorated sensitivity and electromagnetic interference noise.
Innovation Solution
A display device with a mesh-patterned first shield electrode in the non-display region, featuring openings and island-shaped electrode portions, is used to reduce parasitic capacitance and block electromagnetic interference noise, while maintaining effective shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the area of the shield electrode is reduced to reduce parasitic capacitance, then parasitic capacitance decreases and sensitivity improves, but electromagnetic interference noise blocking capability deteriorates
Solution Approach 1:
The shield electrode is divided into multiple separate shield electrodes positioned at different locations. Each shield electrode is optimized for specific functions: some are positioned near power lines to block EMI noise, while others are positioned near wiring lines to minimize parasitic capacitance. This segmentation allows each electrode to be sized appropriately for its specific role without compromising overall performance.
Solution Approach 2:
Different regions of the shield electrode structure have different characteristics optimized for local requirements. Shield electrodes near power lines have larger areas for EMI blocking, while shield electrodes near wiring lines have smaller areas to reduce capacitance. The mesh pattern also provides localized shielding with reduced overall capacitance compared to a solid shield electrode.
2Object-affected harmful factors
If a solid shield electrode is used to block electromagnetic interference noise, then EMI blocking capability improves, but parasitic capacitance increases and sensitivity deteriorates
Solution Approach 1:
The shield electrode employs a mesh pattern with holes throughout its structure. This porous configuration provides electromagnetic shielding capability while significantly reducing the overall capacitance compared to a solid electrode. The mesh pattern allows the shield to block EMI noise through the conductive network while maintaining low parasitic capacitance with the wiring lines.
3Object-affected harmful factors
If the shield electrode is positioned closer to the wiring line to improve shielding, then EMI blocking improves, but parasitic capacitance increases
Solution Approach 1:
The shield electrode is segmented into multiple separate electrodes positioned at different distances from the wiring line. Some shield electrodes are positioned closer to provide EMI blocking, while others are positioned farther away to minimize capacitance. This spatial segmentation allows optimization of both shielding effectiveness and capacitance minimization simultaneously.
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 effectively suppresses capacitive coupling and electromagnetic interference, enhancing the detection sensitivity and reliability of the touch detection device.
Implementation Method 1
a mesh-patterned first shield electrode arranged in a non-display region in the second substrate. The first shield electrode has a first opening and an island-shaped first electrode portion
Implementation Method 2
A display device comprising a sensor which detects contact or approach of an object has been developed. As an example of an electrostatic capacitance type sensor
Implementation Method 3
a detection electrode is provided in the other substrate. A power line for supplying a signal potential is electrically connected to the drive electrode, and a wiring line for reading an output signal is electrically connected to the detection electrode
Data Source
AI summary
A display device is provided and includes a plurality of drive electrodes; a mesh-patterned first shield electrode comprising a plurality of first openings and a first electrode portion located between the first openings adjacent to each other, an area of the first electrode portion being greater than an area of the first openings; and a first power line provided with a predetermined voltage, wherein the first openings and the first electrode portion overlap the first power line.