Substrate Structure with Gradient Refractive Index Layers
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Solution Overview
Problem
Transparent electrodes in touch panels exhibit higher reflectance and lower transmittance due to differences in refractive indexes with upper or lower laminated layers, leading to visible conductive patterns and a compromised appearance.
Innovation Solution
A substrate structure with multiple layers of varying refractive indexes is used between conductive patterns and laminated layers, formed through a sputtering process with controlled gas ratios and power, to minimize refractive index differences and reduce reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transparent electrodes are disposed as conductive patterns in touch panels, then electrical conductivity is improved, but pattern visibility increases due to higher reflectance and lower transmittance
Solution Approach 1:
An intermediate layer with refractive index between that of the transparent electrode and the upper/lower laminated layers is introduced. This intermediate layer acts as a mediator to gradually transition the refractive index, reducing the abrupt difference at interfaces and thereby minimizing reflectance and pattern visibility while maintaining electrical conductivity of the electrode.
Solution Approach 2:
The refractive index parameter is changed by introducing materials with different refractive indices in a gradient manner. By controlling the refractive index of each layer in the laminated structure, the optical properties are optimized to reduce reflectance and improve transparency, thus reducing pattern visibility without affecting the electrical function.
2Object-generated harmful factors
If multiple layers with gradually varying refractive indexes are used, then reflectance is reduced and transmittance is improved, but device complexity increases
Solution Approach 1:
Different layers are assigned different refractive index qualities locally optimized for their position in the structure. The layer adjacent to the electrode has a refractive index closer to the electrode material, while upper layers have refractive indices progressively closer to the surrounding medium, creating a localized gradient that efficiently reduces reflectance without requiring excessive layers.
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 reduces reflectance and improves transmittance, minimizing the visibility of conductive patterns and enhancing the appearance of touch panels.
Implementation Method 1
formed through a sputtering process with controlled gas ratios and power
Data Source
AI summary
A substrate structure with invisible inner electrode patterns is provided. The substrate structure includes a substrate, an electrode pattern, a first laminated structure, and a passivation layer. The electrode pattern is disposed on the substrate. The first laminated structure is disposed on the electrode pattern, in which the first laminated structure includes a first upper layer, a second upper layer, and a third upper layer. The first upper layer is adjoined to the electrode pattern and the substrate. The first upper layer, the second upper layer, and the third upper layer are stacked sequentially. The passivation layer is disposed on the first laminated structure. The refractive indexes of the electrode pattern, the first upper layer, the second upper layer, the third upper layer, and the passivation layer are decreased sequentially.