Touch Sensor Contacting Structure with MoxTay Layer for Stress Compensation
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Solution Overview
Problem
Existing touch sensor configurations face challenges with mechanical stress gradients, corrosion, and electrical conductivity issues due to differences in thermal expansion coefficients and deposition process parameters, leading to substrate distortion, deformation, and potential short circuits, especially in large-area screens and portable devices exposed to environmental stressors.
Innovation Solution
A touch sensor configuration utilizing a contacting structure with a MoxTay layer (0.02≦y≦0.15) for optimal etching behavior, corrosion resistance, and stress compensation, combined with a multilayer structure including Al or Al alloys for high electrical conductivity and reliable adherence, effectively addressing mechanical stress and corrosion concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic contacting structure with high conductivity is used, then electrical conductivity is improved, but mechanical stress gradients cause substrate distortion and deformation
Solution Approach 1:
The patent uses a composite contacting structure consisting of multiple layers: a TCO layer (indium tin oxide) as the base layer, an intermediate layer (chromium or molybdenum), and a top metallic layer (aluminum or copper). This composite structure combines the advantages of each material - the TCO provides good adhesion to the substrate and moderate conductivity, the intermediate layer provides stress compensation and bonding, and the metallic layer provides high conductivity. This multi-layer composite approach resolves the contradiction by distributing mechanical stress across different materials with different thermal expansion coefficients while maintaining overall electrical conductivity.
Solution Approach 2:
The patent optimizes the thickness parameters of each layer in the contacting structure. The TCO layer is kept thin (50-200 nm) to minimize stress, the intermediate layer is optimized (10-50 nm) for stress compensation, and the metallic layer thickness (100-500 nm) is balanced for conductivity versus stress. By carefully controlling these dimensional parameters, the patent achieves both high electrical conductivity and minimal substrate distortion.
2Illumination intensity
If transparent conductive oxide layers are used for electrodes, then optical transparency is improved, but etching behavior and corrosion resistance deteriorate
Solution Approach 1:
The patent applies a multi-layer protective and functional structure on the TCO electrode: the TCO layer itself provides transparency, followed by a protective overcoat layer (such as silicon nitride or silicon oxide) that provides corrosion resistance. Additionally, the intermediate metallic layers (chromium, molybdenum) and top metallic layers (aluminum, copper) form a composite structure that protects the TCO from environmental corrosion while maintaining electrical conductivity. This composite approach allows the TCO to remain transparent while the combined structure provides enhanced corrosion resistance.
3Manufacturing precision
If cathode sputtering and deposition are used for applying layers, then manufacturing precision is improved, but mechanical stress gradients increase
Solution Approach 1:
The patent uses a multi-layer composite contacting structure where each layer is deposited by cathode sputtering with optimized parameters. The different materials (TCO, chromium, molybdenum, aluminum, copper) have different intrinsic stresses from the sputtering process, but the overall composite structure is designed to balance these stresses. The intermediate layers specifically serve to compensate for stress accumulation, allowing precise layer deposition while minimizing net mechanical stress gradients on the substrate.
4Illumination intensity
If the touch sensor configuration is made optically transparent, then visibility of display unit is improved, but structural strength and corrosion resistance worsen
Solution Approach 1:
The patent employs a multi-layer composite structure where transparent layers (TCO, protective overcoats) are combined with metallic layers (chromium, molybdenum, aluminum, copper). The transparent layers maintain optical visibility of the display, while the metallic layers provide structural reinforcement and corrosion protection. The intermediate metallic layers bond the transparent TCO layer to the substrate and provide mechanical strength, creating a composite structure that achieves both transparency and structural integrity.
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 stable and reliable touch sensor configuration with improved etching behavior, corrosion resistance, and stress compensation, ensuring accurate touch detection and preventing substrate distortion and electrical failures, even under environmental stress.
Implementation Method 1
achieves a most advantageous possible etching behavior with at the same time good corrosion resistance and other resistance, highest possible electrical conductivity with lowest possible transfer resistance as well as avoidance as completely as possible of disadvantageous influences caused by mechanical stress gradients in the individual layers
Implementation Method 2
at least one contacting structure for the electrical contacting of the electrically conductive, transparent layer
Implementation Method 3
achieves a most advantageous possible etching behavior with at the same time good corrosion resistance and other resistance
Data Source
AI summary
A touch sensor configuration contains an optically transparent substrate, at least one optically transparent touch sensor element formed on the substrate and has at least one electrically conductive, transparent layer, and at least one contacting structure for the electrical contacting of the electrically conductive, transparent layer. The contacting structure has in direct contact with the electrically conductive, transparent layer at least one layer of MoxTay with 0.02≦y≦0.15.