Touch Screen Panel Sensing Electrode Mesh Structure
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Solution Overview
Problem
Current touch screen panels face limitations such as low recognition speed due to RC delays, potential cracking from bending, and visibility issues due to high reflectivity, particularly in panels with transparent conductive layers or metal mesh structures.
Innovation Solution
The touch screen panel design incorporates a second sensing metal layer with a mesh structure that is thicker than the first sensing metal layer, reducing resistance and improving response speed, while also using transparent conductive oxide layers to minimize reflectivity and enhance absorbance, thereby improving contrast and invisibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent conductive layer or metal mesh structure is used in the touch screen panel, then the sensing electrode can be formed, but the reflectivity increases causing visibility issues
Solution Approach 1:
The patent employs a composite sensing electrode structure consisting of multiple layers: a first transparent conductive layer (ITO), a first metal layer (silver or aluminum), a first transparent insulating layer, a second metal layer (silver or aluminum), and a second transparent conductive layer (ITO). This composite structure achieves both electrical conductivity for sensing and optical transparency by combining materials with complementary properties - the metal layers provide conductivity while the transparent conductive oxide layers and insulating layers control light transmission and reduce reflectivity.
2Speed
If a thicker metal layer is used to reduce resistance, then the response speed improves, but the visibility issues and reflectivity worsen
Solution Approach 1:
The patent divides the sensing electrode into multiple segmented layers rather than using a single thick metal layer. Each layer serves a specific function: the transparent conductive oxide layers provide conductivity with minimal reflectivity, the thin metal layers provide additional conductivity pathways, and the transparent insulating layers electrically isolate components. This segmentation allows the total conductive path to be optimized for low resistance without requiring a single thick reflective layer.
Solution Approach 2:
The patent optimizes the thickness parameters of each layer to achieve the desired balance. The first and second metal layers are each 50-150 nm thick, providing sufficient conductivity while remaining thin enough to minimize reflectivity. The transparent conductive oxide layers are 50-200 nm thick, and the transparent insulating layer is 50-200 nm thick. These parameter optimizations enable low resistance without excessive reflectivity.
3Adaptability or versatility
If the touch screen panel is made flexible to improve user experience, then the form factor improves, but cracking from bending occurs
Solution Approach 1:
The patent employs thin film structures throughout the touch screen panel, including the transparent conductive oxide layers, metal layers, and transparent insulating layers. These thin films are inherently more flexible and resistant to cracking during bending compared to thick rigid structures. The entire sensing electrode is constructed as a thin film stack that can accommodate the mechanical deformation required for flexible displays without cracking.
4Speed
If multiple layers are added to reduce resistance and improve response speed, then the electrical performance improves, but the device complexity increases
Solution Approach 1:
The patent combines multiple functional requirements into a single integrated sensing electrode structure. The first transparent conductive layer, first metal layer, first transparent insulating layer, second metal layer, and second transparent conductive layer work together as one unified sensing electrode that provides both X and Y direction sensing capabilities. This merging approach achieves low resistance and fast response speed without requiring separate structures for different functions, thereby limiting the increase in overall 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 design enhances response speed, reduces visibility issues, and improves contrast by reducing the reflectivity and thickness of the sensing electrodes, leading to a more reliable and user-friendly touch screen experience.
Implementation Method 1
The second sensing metal layer 122b having the mesh structure may have a greater thickness than a thickness of the first sensing metal layer 122a. As such, resistance of the sensing electrode 122 may be reduced, and response speed may be improved
Implementation Method 2
using transparent conductive oxide layers to minimize reflectivity and enhance absorbance, thereby improving contrast and invisibility
Data Source
AI summary
A touch screen panel includes a sensing electrode area, a pad area, and a peripheral wiring area. The sensing electrode area includes first sensing electrodes and second sensing electrodes on a touch substrate and spaced from each other. The peripheral wiring area connects the sensing electrode area to the pad area. Each of the first sensing electrodes includes a first sensing metal layer on the touch substrate, a sensing insulation layer on the first sensing metal layer, and a second sensing metal layer on the sensing insulation layer and having a mesh structure. The second sensing metal layer is thicker than the first sensing metal layer.