Touch Panel Composite Electrodes for Environmental Stability
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Solution Overview
Problem
Conventional touch panels with silver and carbon powder dispersed in resin materials face increased resistance and voltage drop issues, especially in large sizes and harsh environments like high-temperature, high-humidity conditions, affecting detection accuracy and environmental durability.
Innovation Solution
A touch panel design featuring an upper substrate with a highly light-transmitting conductive layer, an intermediate layer containing 40 wt. % to 90 wt. % carbon, and upper and lower electrodes with 70 wt. % to 98 wt. % conductive metal, where the intermediate layer improves electrical stability and resistance to environmental factors by maintaining contact resistance below 3Ω even after 500 hours in challenging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver powder and carbon powder are dispersed in resin to form electrodes, then electrical connection stability in harsh environments is improved, but electrode resistance increases causing voltage drop
Solution Approach 1:
The patent uses a composite material consisting of silver powder (70-98 wt%), carbon powder (1-30 wt%), and resin (2-30 wt%) to create an electrode that combines the high conductivity of silver with the environmental stability of carbon-resin composite, thereby reducing voltage drop while maintaining connection stability in harsh environments
Solution Approach 2:
The patent optimizes the weight percentages of silver powder, carbon powder, and resin within specific ranges to achieve the desired balance between conductivity and environmental resistance, allowing parameter adjustment to meet different performance requirements
2Reliability
If carbon powder particles are made fine to improve conductivity, then electrical connection is enhanced, but particles aggregate reducing effectiveness
Solution Approach 1:
The patent specifies that carbon powder particles with fine粒径 (30-40 nm) should have high specific surface area (BET ≥700 m2/g) to enhance conductivity at critical contact points, while the overall composite structure maintains uniform dispersion through controlled aggregation in the resin matrix
Solution Approach 2:
The combination of fine carbon powder with resin creates a composite structure where the resin acts as a dispersant and binding agent, preventing aggregation of ultra-fine carbon particles while maintaining their high surface area for electrical conduction
3Area of stationary object
If touch panel size is increased for various applications, then functionality is improved, but resistance increases causing detection accuracy to deteriorate
Solution Approach 1:
The patent changes the electrode material parameters by using high silver content (70-98 wt%) composite material that maintains low resistance even over large distances, allowing the touch panel to be scaled up while preserving detection accuracy through superior electrical conductivity
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 design enhances the touch panel's environmental resistance and detection accuracy by stabilizing electrical connections and preventing moisture infiltration, making it suitable for large sizes and harsh environments while maintaining low contact resistance.
Implementation Method 1
The intermediate layer contains a resin and 40 wt. % to 90 wt. % of carbon and has a thickness ranging from 1 μm to 50 μm
Implementation Method 2
connect fine carbon powder particles into chain structures and to disperse the carbon powder particles between silver powder particles
Implementation Method 3
An adhesive agent constituting adhesive layer 3 is applied onto the peripheries of upper substrate 11 and lower substrate 21 to bond substrates 11 to substrate 12
Implementation Method 4
Insulating layer 14 covers upper electrode 13, while insulating layer 24 covers lower electrode 23
Data Source
AI summary
A touch panel includes an upper substrate having insulating property, an upper conductive layer on a lower surface of the upper substrate, an intermediate layer on a lower surface of the upper conductive layer, an upper electrode on a lower surface of the intermediate layer, a lower conductive layer facing the upper conductive layer with a predetermined gap interposed between the conductive layers, a lower electrode on an upper surface of the lower conductive layer, and a lower substrate on a lower surface of the lower conductive layer and having insulating property. The upper and lower electrodes contain 70 wt. % to 98 wt. % of conductive metal. The intermediate layer contains a resin and 40 wt. % to 90 wt. % of carbon and has a thickness ranging from 1 μm to 50 μm. The touch panel has resistance to environment and is applicable to a large size.