Touch Sensor Signal Line Stack for Humidity-Resistant Displays
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Solution Overview
Problem
Existing display devices face challenges in maintaining reliable touch input functionality under harsh conditions such as high humidity or mechanical stress, leading to signal degradation and reduced image quality.
Innovation Solution
The display device incorporates a signal line structure with three metal layers: a first layer of molybdenum-niobium (MoNb) alloy for corrosion resistance and adhesion, a second layer of aluminum-neodymium (AlNd) alloy for high electrical conductivity, and a third MoNb alloy layer for hardness and protection against scratches, along with transparent indium tin oxide (ITO) electrodes for accurate input detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer signal line is used, then the device complexity is reduced, but the reliability deteriorates under harsh conditions such as high humidity or mechanical stress
Solution Approach 1:
The signal line is constructed using a composite structure with three different metal layers: a first metal layer (e.g., MoNb alloy) providing corrosion resistance and adhesion, a second metal layer (e.g., AlNd alloy) providing high electrical conductivity, and a third metal layer (e.g., MoNb alloy) providing hardness and scratch resistance. This composite structure resolves the contradiction by combining materials with different properties to achieve overall reliability without excessive complexity.
2Reliability
If additional metal layers are added to the signal line, then the corrosion resistance and hardness are improved, but the manufacturing complexity increases
Solution Approach 1:
The signal line is segmented into three distinct metal layers, each with a specific thickness and material composition optimized for its function. This segmentation allows each layer to be manufactured and controlled independently, making the overall manufacturing process more manageable despite the increased number of layers.
Solution Approach 2:
The patent specifies precise parameter ranges for each metal layer, including thickness (e.g., first metal layer: 50-200 nm, second metal layer: 200-500 nm, third metal layer: 50-200 nm) and material composition (e.g., MoNb alloy with 1-10 at% Nb, AlNd alloy with 1-5 at% Nd). These parameter specifications standardize the manufacturing process, reducing complexity through defined tolerances and repeatable procedures.
3Reliability
If a complex multi-layer signal line structure is used, then the electrical conductivity and signal transmission are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for each layer thickness and material composition that optimize electrical conductivity while remaining manufacturable. For example, the second metal layer (AlNd alloy) is specified at 200-500 nm to ensure sufficient conductivity, while the outer MoNb layers at 50-200 nm each provide protection without excessive total thickness. These parameter specifications balance performance requirements with manufacturing precision capabilities.
Data Source
AI summary
A display device includes: a display panel including a light-emitting element; and an input sensor disposed on the display panel and including a first insulating layer, a sensing electrode, and a signal line electrically connected to the sensing electrode, wherein the sensing electrode includes: a first sensing conductive layer disposed on the first insulating layer; and a second sensing conductive layer electrically connected to the first sensing conductive layer and disposed on the first insulating layer, and the signal line includes: a first metal layer including molybdenum-niobium (MoNb) alloy; a second metal layer including aluminum-neodymium (AlNd) alloy and disposed on the first metal layer; and a third metal layer including molybdenum-niobium (MoNb) alloy and disposed on the second metal layer.