Touch Panel Protective Layer Refractive Index Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional touch panels suffer from visibility issues due to the difference in refractive indices between the transparent electrode and substrate, leading to framework visibility and taper visibility, as well as high total reflection of visible light, making them difficult to use outdoors.
Innovation Solution
A touch panel member with a protective layer comprising three or more layers of different refractive indices, where the difference between adjacent layers is within specific ranges, and the refractive index of each layer is carefully controlled to minimize reflection and visibility, with the transparent electrode having a refractive index between 1.76 and 2.30, and the protective layer covering the electrode to reduce external light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single protective layer is used, then the structure is simple, but the visibility of the transparent electrode and total reflection are not suppressed
Solution Approach 1:
The protective layer is divided into multiple sub-layers (first protective layer, second protective layer, third protective layer) with different refractive indices. This segmentation allows each layer to contribute differently to suppressing visibility and reflection, with the first layer having refractive index closest to the transparent electrode, the second layer having intermediate refractive index, and the third layer having refractive index closest to the substrate, creating a gradient that progressively reduces optical discontinuities.
Solution Approach 2:
The refractive indices of the protective layer sub-layers are specifically controlled to satisfy defined relationships with the transparent electrode and substrate refractive indices. The first protective layer has refractive index n1 satisfying |n1 - nelectrode| ≤ 0.20, the second protective layer has refractive index n2, and the third protective layer has refractive index n3 satisfying n3 - nelectrode ≥ 0.20, creating an optimized optical parameter gradient.
2Object-affected harmful factors
If the refractive index difference between layers is large, then the visibility suppression is effective, but the total reflection increases
Solution Approach 1:
Each protective layer sub-layer is designed with specific local optical properties (refractive index) tailored to its position in the stack. The first protective layer has refractive index optimized for matching the transparent electrode, the second protective layer has intermediate properties, and the third protective layer has refractive index optimized for matching the substrate, creating localized optimization at each interface.
Solution Approach 2:
The multiple protective layers with intermediate refractive indices act as optical mediators between the transparent electrode and the substrate. Rather than a single abrupt interface, the intermediate layers gradually transition the refractive index, reducing both visibility discontinuities and total reflection through progressive optical matching.
3Object-affected harmful factors
If the transparent electrode refractive index is high, then the visibility is suppressed, but the total reflection increases
Solution Approach 1:
The refractive index of the transparent electrode is controlled within a specific range (1.76 ≤ nelectrode ≤ 2.30) to balance visibility suppression and reflection characteristics. Additionally, the protective layers have refractive indices specifically related to the electrode refractive index through defined mathematical relationships, creating an optimized parameter set that simultaneously achieves both goals.
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 the visibility of the transparent electrode and reduces total reflection, enhancing the usability of touch panels, especially in outdoor conditions by minimizing light reflection and framework visibility.
Implementation Method 1
the protective layer comprising three or more layers having different refractive indices, all of the different refractive index layers of the protective layer satisfying Expression (1)... the refractive index of an a-th layer of the protective layer is defined as n(a)... 0(n(x))-n(x+1)≤0.20
Data Source
AI summary
The object of the present invention is to provide a touch panel member that is excellent in terms of suppression of visibility of a transparent electrode and has low total reflection for visible light, and a touch panel and a touch panel display device having the touch panel member.The touch panel member of the present invention comprises, in order, at least a transparent substrate, a transparent electrode, and a protective layer provided so as to cover the transparent electrode, the protective layer comprising three or more layers having different refractive indices, all of the different refractive index layers of the protective layer satisfying a specific expression, and the protective layer satisfying another specific expression.