Laminated Touch Panel With Refractive Index Matching Layer
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Solution Overview
Problem
Conventional touch panel technologies face issues with visibility due to differences in optical properties between conductive and non-conductive layers, leading to pattern emphasis and reduced transmittance, and require high annealing temperatures that can cause substrate deformation and oligomer precipitation.
Innovation Solution
A laminated body with a first layer and a second layer of different refractive indices, containing inorganic particles, is applied on a support substrate, using a coating composition that includes a fluorine polymer and inorganic particles, allowing for lower temperature annealing and improved alkali resistance, reducing pattern visibility and transmittance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transparent conductive films are used, then conductivity is achieved, but pattern visibility increases and transmittance decreases due to great difference in optical properties
Solution Approach 1:
The patent introduces an optically functional layer as an intermediary between the transparent conductive thin-film layer and the substrate film. This layer has a refractive index different from both the conductive layer and substrate, serving as a mediator to reduce optical property differences and minimize pattern visibility while maintaining conductivity.
Solution Approach 2:
The patent changes the refractive index parameter by introducing an optically functional layer with a specific refractive index (1.30-1.60) that differs from both the substrate film (1.50-1.70) and the transparent conductive layer. This parameter change reduces optical contrast and improves transmittance.
2Reliability
If high annealing temperature is used to improve conductivity, then electrical properties improve, but substrate deformation and oligomer precipitation occur
Solution Approach 1:
The patent changes the temperature parameter from conventional high annealing temperatures to a lower range (50-150°C). This parameter change allows sufficient conductivity improvement while preventing substrate deformation and oligomer precipitation that occur at higher temperatures.
Solution Approach 2:
The patent uses a composite structure with multiple layers including the optically functional layer and transparent conductive layer, where each layer contributes specific properties. This composite approach enables lower annealing temperatures while achieving desired conductivity through the synergistic effect of the layered structure.
3Illumination intensity
If refractive index-adjusting layer is added to reduce pattern visibility, then transmittance improves, but alkali resistance decreases
Solution Approach 1:
The patent creates a composite structure where the optically functional layer (providing refractive index adjustment) is combined with an overcoat layer (providing alkali resistance). This composite approach allows the system to simultaneously achieve improved transmittance through refractive index matching and enhanced alkali resistance through the protective overcoat layer.
Solution Approach 2:
The patent segments the optically functional layer into distinct functional components: one layer optimized for refractive index adjustment and another overcoat layer optimized for alkali resistance. This segmentation allows each layer to specialize in its primary function without compromising the other property.
4Adaptability or versatility
If patterned conductive layer is created for touch panel, then touch detection function is achieved, but optical uniformity deteriorates due to pattern emphasis
Solution Approach 1:
The patent introduces the optically functional layer as a mediator between the patterned conductive layer and the substrate. This layer reduces the optical contrast of the conductive pattern through refractive index matching, allowing the touch detection function to be maintained while improving optical uniformity across the display.
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 provides a laminated body with enhanced alkali resistance and reduced observation angle dependence, achieving high light transmittance and conductivity while minimizing pattern visibility, even when subjected to alkaline solutions during patterning.
Implementation Method 1
utilize interference of light with layers having different refractive indices laminated
Implementation Method 2
A laminated body with a first layer and a second layer of different refractive indices, containing inorganic particles, is applied on a support substrate, using a coating composition that includes a fluorine polymer and inorganic particles
Data Source
AI summary
A laminated body is a laminated body that has in this order a second layer and a first layer with different indices of refraction on at least one surface of a supporting base material, and the first layer contains particles X (particles X being particles having at least an inorganic particle part), with the second layer containing particles Y (particles Y being particles having at least an inorganic particle part) and is characterized by the number average particle size (DX in the following) for the inorganic particle parts for the particles X being 5-25 nm and by Equations 1 and 2 being satisfied:1.4≦(LX/DX)≦3 1SLX≦7 2.