Second Conductive Layer Static Discharge in Display Devices
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Solution Overview
Problem
Touch detection devices with integrated display functions face challenges in effectively managing static electricity, which can degrade display quality and reduce touch detection accuracy due to the conductive film's susceptibility to electro-static discharge (ESD) and the difficulty in discharging static electricity from the polarizing plate and detection electrodes.
Innovation Solution
A display device configuration that includes a substrate with detection electrodes, a first conductive layer in the peripheral region, a protective layer on the detection electrodes, a polarizing plate above the protective layer, and a second conductive layer with higher sheet resistance than the metal wires, electrically coupled to the first conductive layer, which facilitates the discharge of static electricity through the conductive adhesive layer to the shielding layer and ultimately to ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective layer is provided on the detection electrodes to protect them, then the detection electrodes are protected from damage, but the conductive film becomes electrically isolated from the touch detection electrodes and accumulates static electricity on the polarizing plate
Solution Approach 1:
A second conductive layer with higher sheet resistance than the metal wires is introduced as an intermediary between the protective layer and the first conductive layer. This intermediate layer allows controlled discharge of static electricity while maintaining the protective isolation of the protective layer, thus resolving the contradiction between protection and static electricity accumulation.
Solution Approach 2:
The sheet resistance of the second conductive layer is specifically controlled to be higher than that of the metal wires in the detection electrodes. This parameter change enables the layer to function as a static electricity discharge path while maintaining electrical isolation for protection, balancing both requirements.
2Reliability
If the conductive film is used as a preventative measure against electro-static discharge (ESD), then ESD protection is provided, but static electricity still accumulates on the polarizing plate due to electrical isolation
Solution Approach 1:
The second conductive layer serves as a mediator that enables static electricity discharge from the polarizing plate to the first conductive layer while maintaining the protective electrical isolation provided by the protective layer, thus preserving ESD protection functionality while eliminating static electricity accumulation.
Solution Approach 2:
The second conductive layer is provided in the peripheral region located to the outside of the display region, creating a localized discharge path that does not interfere with the touch detection function in the display region while effectively discharging static electricity accumulated on the polarizing plate.
3Object-affected harmful factors
If a second conductive layer with higher sheet resistance than metal wires is provided between the polarizing plate and protective layer, then static electricity discharge is facilitated, but device structure becomes more complex
Solution Approach 1:
The second conductive layer is designed to serve multiple functions: it provides a static electricity discharge path, maintains electrical isolation through its higher sheet resistance, and can be integrated with the peripheral circuit structure. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device 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
This configuration effectively prevents the polarizing plate and detection electrodes from being charged, thereby enhancing display quality and touch detection accuracy by ensuring efficient discharge of static electricity, thus making the display device more resistant to electromagnetic noise.
Implementation Method 1
a second conductive layer provided between the polarizing plate and the protective layer in a direction perpendicular to the substrate. The second conductive layer has a higher sheet resistance than the metal wires and is electrically coupled to the first conductive layer
Data Source
AI summary
A detection device is provided and includes a first substrate; a plurality of detection electrodes arranged in a first direction and a second direction intersecting the first direction, and located in a display region; a second substrate facing the first substrate; a first conductive layer provided in a peripheral region located outside the display region in planar view, and including a plurality of wires forming a mesh-like pattern; and a second conductive layer electrically coupled to the first conductive layer, the second substrate being located between the second conductive layer and the first substrate, wherein the first conductive layer is arranged to be part of an electrically connected loop around the display region.